Obesity in childhood or adolescence has been recognized to be a risk factor for the onset of lifestyle-related diseases, not only in healthy children, but also in children with developmental disorders. Therefore, this...Obesity in childhood or adolescence has been recognized to be a risk factor for the onset of lifestyle-related diseases, not only in healthy children, but also in children with developmental disorders. Therefore, this study was conducted to examine the characteristics of obesity and thinness as assessed by the body fat percentage among children with developmental disorders during certain growth periods. It was also designed to investigate those factors associated with obesity and thinness based on a lifestyle and behavioral questionnaire. The subjects included 260 children from 5 to 18 years old with developmental disorders. The results of the study showed that a decrease in thinness and increase in obesity with ageing exhibited more noticeable trends among those children with mental retardation. The factors associated with obesity in children with developmental disorders were characterized by the dietary content, eating behaviors, and food preferences particular to such children, as well as low physical activity and a family history of obesity. The results of this study suggested the importance of continuous guidance along with family participation in order to improve obesity among children with developmental disorders, while focusing on the characteristics of certain growth periods.展开更多
The aim of this study was to investigate the relationship among body image perceptions, a desire for thinness, and dieting behavior in young females in Japan. The subjects were 302 Japanese female university students ...The aim of this study was to investigate the relationship among body image perceptions, a desire for thinness, and dieting behavior in young females in Japan. The subjects were 302 Japanese female university students (age 19.9 ± 1.4 years). An anonymous, self-administered questionnaire survey was conducted between July and August 2011. The questionnaire clarified the subjects’ physical status, perception about personal body shape, desired body shape, the time frame when they first thought about body shape dieting, exercise habits, and eating behaviors. The results revealed that many of the underweight or normal weight subjects perceived themselves as obese, and often the reasons for the perception of obesity were comparisons with others or with themselves in the past. The scores of EAT-26 in those who perceived themselves as obese were higher than the scores in those who did not. Those who perceived themselves as obese had a desire to become slim, were concerned about body shape at an early age, were concerned about dieting, had dieting experience, and were willing to increase daily exercise. These results indicated that incorrect perceptions about body shape have connection to a desire for thinness and dieting behavior.展开更多
Light levels determine regeneration in stands and a key concern is how to regulate the light environment of different stand types to the requirements of the understory.In this study,we selected three stands typical in...Light levels determine regeneration in stands and a key concern is how to regulate the light environment of different stand types to the requirements of the understory.In this study,we selected three stands typical in south China(a Cryptomeria japonica plantation,a Quercus acutissima plantation,and a mixed stand of both)and three thinning intensities to determine the best understory light environ-ment for 3-year-old Phoebe bournei seedlings.The canopy structure,understory light environment,and photosynthe-sis and growth indicators were assessed following thin-ning.Thinning improved canopy structure and understory light availability of each stand;species composition was the reason for differences in the understory light environ-ment.Under the same thinning intensity,the mixed stand had the greatest light radiation and most balanced spectral composition.P.bournei photosynthesis and growth were closely related to the light environment;all three stands required heavy thinning to create an effective and sustained understory light environment.In a suitable understory light environment,the efficiency of light interception,absorption,and use by seedlings was enhanced,resulting in a higher carbon assimilation the main limiting factor was stomatal conductance.As a shade-avoidance signal,red/far-red radia-tion is a critical factor driving changes in photosynthesis and growth of P.bournei seedlings,and a reduction increased light absorption and use capacity and height:diameter ratios.The growth advantage transformed from diameter to height,enabling seedlings to access more light.Our findings suggest that the regeneration of shade-tolerant species such as P.bournei could be enhanced if a targeted approach to thinning based on stand type was adopted.展开更多
Thinning is an effective management step for sustainable forest development,yet less attention is paid to the restoration of soil microbiota after thinning.In this study,both abundant and rare soil microbial communiti...Thinning is an effective management step for sustainable forest development,yet less attention is paid to the restoration of soil microbiota after thinning.In this study,both abundant and rare soil microbial communities(i.e.,bacterial,fungal),were evaluated under various thinning treatments in a mixed stand of Cunninghamia lanceolata and Sassafras tzumu using Mi Seq sequencing.Thinning did not significantly change either abundant or rare bacterial and fungal community composition,but affected their alpha diversity.The Shannon–Wiener indexes of rare fungal taxa under medium thinning were significantly lower than in the light thinning(P<0.05 level).Xanthobacteraceae dominated the abundant bacterial taxa,and Saitozyma and Mortierlla the abundant fungal taxa.The most common rare bacterial taxa varied;there was no prevalent rare fungal taxa under different thinnings.In addition,soil available nitrogen,total phosphorus,and p H had significant effects on rare bacterial taxa.Nutrients,especially available phosphorus,but not nitrogen,affected abundant and rare soil fungi.The results indicate that soil properties rather than plant factors affect abundant and rare microbial communities in soils of mixed stands.Thinning,through mediating soil properties,influences both abundant and rare bacterial and fungal communities in the mixed C.lanceolata and S.tzumu stand.展开更多
Interest in the dynamics of soil respiration(R_(S))in subalpine forest ecosystems is increasing due to their high soil carbon density and potential sensitivity to environmental changes.However,as a principal silvicult...Interest in the dynamics of soil respiration(R_(S))in subalpine forest ecosystems is increasing due to their high soil carbon density and potential sensitivity to environmental changes.However,as a principal silvicultural practice,the long-term impacts of thinning on R_(S) and its heterotrophic and autotrophic respiration components(R_(h) and Ra,respectively)in subalpine plantations are poorly understood,espe-cially in winter.A 3-year field observation was carried out with consideration of winter CO_(2) efflux in middle-aged sub-alpine spruce plantations in northwestern China.A trench-ing method was used to explore the long-term impacts of thinning on Rs,Rn and R_(a).Seventeen years after thinning,mean annual Rs,Rn and R_(a) increased,while the contribu-tion of R_(h) to R_(s) decreased with thinning intensity.Thinning significantly decreased winter R,because of the reduction in R_(n) but had no significant effect on Ra.The temperature sensitivity(Q_(10))of R_(h) and R_(a) also increased with thinning intensity,with lower Q_(10) values for R_(h)(2.1-2.6)than for Ra(2.4-2.8).The results revealed the explanatory variables and pathways related to R_(n) and R_(a) dynamics.Thinning increased soil moisture and nitrate nitrogen(NO_(3)^(-)-N),and the enhanced nitrogen and water availability promoted R_(h) and R_(a) by improving fine root biomass and microbial activity.Our results highlight the positive roles of NO_(3)^(-)-N in stimulating R_(s) components following long-term thinning.Therefore,applications of nitrogen fertilizer are not recommended while thinning subalpine spruce plantations from the perspective of reducing soil CO_(2) emissions.The increased Q_(10) values of R_(s) components indicate that a large increase in soil CO_(2) emissions would be expected following thinning because of more pronounced climate warming in alpineregions.展开更多
Understanding the relationship between forest management and water use efficiency(WUE)is important for evaluating forest adaptability to climate change.However,the effects of thinning and understory removal on WUE and...Understanding the relationship between forest management and water use efficiency(WUE)is important for evaluating forest adaptability to climate change.However,the effects of thinning and understory removal on WUE and its key controlling processes are not well understood,which limits our comprehension of the physiological mechanisms of various management practices.In this study,four forest management measures(no thinning:NT;understory removal:UR;light thinning:LT;and heavy thinning:HT)were carried out in Pinus massoniana plantations in a subtropical region of China.Photosynthetic capacity and needle stable carbon isotope composition(δ^(13)C)were measured to assess instantaneous water use efficiency(WUE_(inst))and long-term water use efficiency(WUE_(i)).Multiple regression models and structural equation modelling(SEM)identified the effects of soil properties and physiological performances on WUE_(inst)and WUE_(i).The results show that WUE_(inst)values among the four treatments were insignificant.However,compared with the NT stand(35.8μmol·mol^(-1)),WUE_(i)values significantly increased to 41.7μmol·mol^(-1)in the UR,50.1μmol·mol^(-1)in the LT and 46.6μmol·mol^(-1)in HT treatments,largely explained by photosynthetic capacity and soil water content.Understory removal did not change physiological performance(needle water potential and photosynthetic capacity).Thinning increased the net photosynthetic rate(A_n)but not stomatal conductance(g_s)or predawn needle water potential(ψ_(pd)),implying that the improvement in water use efficiency for thinned stands was largely driven by radiation interception than by soil water availability.In general,thinning may be an appropriate management measure to promote P.massoniana WUE to cope with seasonal droughts under future extreme climates.展开更多
Background:As is widely known,an increasing number of forest areas were managed to preserve and enhance the health of forest ecosystems.However,previous research on forest management has often overlooked the importanc...Background:As is widely known,an increasing number of forest areas were managed to preserve and enhance the health of forest ecosystems.However,previous research on forest management has often overlooked the importance of structure-based.Aims:Our objectives were to define the direction of structure-based forest management.Subsequently,we investigated the relationships between forest structure and the regeneration,growth,and mortality of trees under different thinning treatments.Ultimately,the drivers of forest structural change were explored.Methods:On the basis of 92 sites selected from northeastern China,with different recovery time (from 1 to 15years) and different thinning intensities (0–59.9%) since the last thinning.Principal component analysis (PCA)identified relationships among factors determining forest spatial structure.The structural equation model (SEM)was used to analyze the driving factors behind the changes in forest spatial structure after thinning.Results:Light thinning (0–20%trees removed) promoted forest regeneration,and heavy thinning (over 35% of trees removed) facilitated forest growth.However,only moderate thinning (20%–35%trees removed) created a reasonable spatial structure.While dead trees were clustered,and they were hardly affected by thinning intensity.Additionally,thinning intensity,recovery time,and altitude indirectly improve the spatial structure of the forest by influencing diameter at breast height (DBH) and canopy area.Conclusion:Creating larger DBH and canopy area through thinning will promote the formation of complex forest structures,which cultivates healthy and stable forests.展开更多
Designing a sparse array with reduced transmit/receive modules(TRMs)is vital for some applications where the antenna system’s size,weight,allowed operating space,and cost are limited.Sparse arrays exhibit distinct ar...Designing a sparse array with reduced transmit/receive modules(TRMs)is vital for some applications where the antenna system’s size,weight,allowed operating space,and cost are limited.Sparse arrays exhibit distinct architectures,roughly classified into three categories:Thinned arrays,nonuniformly spaced arrays,and clustered arrays.While numerous advanced synthesis methods have been presented for the three types of sparse arrays in recent years,a comprehensive review of the latest development in sparse array synthesis is lacking.This work aims to fill this gap by thoroughly summarizing these techniques.The study includes synthesis examples to facilitate a comparative analysis of different techniques in terms of both accuracy and efficiency.Thus,this review is intended to assist researchers and engineers in related fields,offering a clear understanding of the development and distinctions among sparse array synthesis techniques.展开更多
Management of the Pointe-Noire Forest requires high-performance tools for simulating tree and stand growth and assessing the sustainability of plantations. Modelling the dynamics of even-aged and mono-species stands i...Management of the Pointe-Noire Forest requires high-performance tools for simulating tree and stand growth and assessing the sustainability of plantations. Modelling the dynamics of even-aged and mono-species stands is a very active research topic. The approaches adopted by researchers vary according to the objectives and species considered: dendrometrical, Eco physiological or architectural. Thanks to the particular nature of these plantations and the trial set-up, it will be possible to explore the various aspects of production, clearly separating the part linked to genetics (three clones tested) from the part linked to the environment (via fertilisation) and the part associated with competition between trees (via planting densities and thinning regimes). This study will make a major contribution to the applicability of the self-thinning line and the RDI (Reineke Density Index) (Reineke, 1933) to fast-growing plantations. This research work will contribute to two points: 1) product diversification, which is a way of coping with international variations in timber markets, and 2) understanding how ecosystems function in exceptionally poor conditions, which will then enable the environmental impacts of the various recommended silvicultural itineraries to be assessed. The results obtained show that competition between trees in a stand of eucalyptus at very high density (10,000 stems/ha) and in two environments of very contrasting fertility is different depending on the clone. The decision on the date of the first thinning with a view to silviculture for timber and energy wood, which aims to ensure sustained and sustainable production of eucalyptus wood in these soils, should be taken between 12 and 14 months. The competition band is strong between 14 and 17 months, when the RDI = 0.8 is double that observed at 12 months.展开更多
Thinning is a widely used forest management tool but systematic research has not been carried out to verify its eff ects on carbon storage and plant diversity at the ecosystem level.In this study,the eff ect of thinni...Thinning is a widely used forest management tool but systematic research has not been carried out to verify its eff ects on carbon storage and plant diversity at the ecosystem level.In this study,the eff ect of thinning was assessed across seven thinning intensities(0,10,15,20,25,30 and 35%)in a low-quality secondary forest in NE China over a ten-year period.Thinning aff ected the carbon storage of trees,and shrub,herb,and soil layers(P<0.05).It fi rst increased and then decreased as thinning intensity increased,reaching its maximum at 30%thinning.Carbon storage of the soil accounted for more than 64%of the total carbon stored in the ecosystem.It was highest in the upper 20-cm soil layer.Thinning increased tree species diversity while decreasing shrub and herb diversities(P<0.05).Redundancy analysis and a correlation heat map showed that carbon storage of tree and shrub layers was positively correlated with tree diversity but negatively with herb diversity,indicating that the increase in tree diversity increased the carbon storage of natural forest ecosystems.Although thinning decreased shrub and herb diversities,it increased the carbon storage of the overall ecosystem and tree species diversity of secondary forest.Maximum carbon storage and the highest tree diversity were observed at a thinning intensity of 30%.This study provides evidence for the ecological management of natural and secondary forests and improvement of ecosystem carbon sinks and biodiversity.展开更多
Background:Chinese pine(Pinus tabuliformis Carr.)is one of the major afforestation species in northern China and plays a key role in restoring forest ecosystems and preserving soil and water.However,most Chinese pine ...Background:Chinese pine(Pinus tabuliformis Carr.)is one of the major afforestation species in northern China and plays a key role in restoring forest ecosystems and preserving soil and water.However,most Chinese pine plantations are experiencing ecological problems such as the low diversity of understory plants and difficulty in natural regeneration.Thinning has been widely used to maintain and improve a variety of forest ecosystem services from plantations.To date,however,few studies have been conducted to systematically determine the effects of thinning on understory plant diversity and the regeneration of Chinese pine in plantations.Methods:We conducted a literature search,and selected 22 publications covering a total of 83 treatments related to thinning effects on the species richness of understory plants and 15 publications covering a total of 43 treatments related to thinning effects on the regeneration of Chinese pine,in tree plantations of northern China.The data from the literature were synthesized and evaluated with meta-analysis approach to determine the treatment effects.Results:Compared with the control stands,thinning increased the species richness of shrubs and herbs by an average of 25.3%and 26.5%,respectively.While the varying thinning intensities all had significantly positive effects on the species richness of understory plants,only moderate thinning(30%–50%)had a positive effect on the density of regenerating seedlings and saplings of Chinese pine(60.2%).The species richness of understory plants was greatest after 14 years of thinning with an increase of 36.3%,whereas the density of regenerating Chinese pine seedlings and saplings reached a maximum after≥11 years of thinning with an increase of 76.5%,compared to that of the unthinned stands.Thinning in the half-mature plantations had the greatest effects on the understory shrub richness(44.1%)and the density of regenerating Chinese pine seedlings and saplings(86.5%).Both single and multiple thinning were found to significantly promote the species richness of understory plants and the density of regenerating Chinese pine seedlings and saplings,and the positive effects of thinning were greater in areas with a humidity index(HI)<30 than in areas with an HI≥30.In general,age group,planting density and recovery time were prominent factors affecting the species richness of understory plants,whereas the slope,HI and recovery time were the dominant controls of the density of regenerating Chinese pine seedlings and saplings,indicating differential effects of thinning on the species richness of understory plants and the regeneration capacity of Chinese pine in plantations.Conclusion:Thinning appears to be a feasible management measure to improve the understory plant diversity and regeneration capacity of Chinese pine in plantations.We postulate that moderate thinning in half-mature forest stands with an HI<30 can help effectively promote the species diversity of understory plants and the natural regeneration of Chinese pine,thereby maintaining a more resilient stand structure and the development of Chinese pine plantations.展开更多
To explore how to respond to seasonal freeze–thaw cycles on forest ecosystems in the context of climate change through thinning,we assessed the potential impact of thinning intensity on carbon cycle dynamics.By varyi...To explore how to respond to seasonal freeze–thaw cycles on forest ecosystems in the context of climate change through thinning,we assessed the potential impact of thinning intensity on carbon cycle dynamics.By varying the number of temperature cycles,the eff ects of various thinning intensities in four seasons.The rate of mass,litter organic carbon,and soil organic carbon(SOC)loss in response to temperature variations was examined in two degrees of decomposition.The unfrozen season had the highest decomposition rate of litter,followed by the frozen season.Semi-decomposed litter had a higher decomposition rate than undecomposed litter.The decomposition rate of litter was the highest when the thinning intensity was 10%,while the litter and SOC were low.Forest litter had a good carbon sequestration impact in the unfrozen and freeze–thaw seasons,while the converse was confi rmed in the frozen and thaw seasons.The best carbon sequestration impact was identifi ed in litter,and soil layers under a 20–25%thinning intensity,and the infl uence of undecomposed litter on SOC was more noticeable than that of semi-decomposed litter.Both litter and soil can store carbon:however,carbon is transported from undecomposed litter to semi-decomposed litter and to the soil over time.In summary,the best thinning intensity being 20–25%.展开更多
Elevation gradients within forested wetlands have long been recognized for their role in defining species composition through factors such as hydrology and soil characteristics.Greentree reservoirs(GTRs)are leveeimpou...Elevation gradients within forested wetlands have long been recognized for their role in defining species composition through factors such as hydrology and soil characteristics.Greentree reservoirs(GTRs)are leveeimpounded tracts of bottomland hardwood forest flooded throughout the winter months to provide habitat for overwintering waterfowl.Artificial flooding of GTRs alters the forest composition due to flood frequency,depth,and duration in combination with slight changes in topography.To evaluate the effect of elevation gradients,soil properties,and management techniques in the overstory species composition and red oak(Quercus spp.)species abundance,we inventoried 662 plots across 12 independent GTRs in eastern Arkansas.In the lower elevations ranging from 50.98 to 54.99 m above sea level,the importance value index(IVI)was highest for nuttall oak(Quercus texana)and overcup oak(Quercus lyrata),whereas IVI shifted to cherrybark oak(Quercus pagoda)in the higher elevations ranging from 54.99 to 58.00 m.Alpha diversity did not differ by elevation gradient,soil property,or management technique within GTRs.Beta diversity,using non-metric multi-dimensional scaling(NMDS)analysis,indicated site-specific variability significantly correlated with the environmental predictors,including elevation(R^(2)=0.57),easting(R^(2)=0.47),soil texture(R^(2)=0.21),and pH(R^(2)=0.12).Red oak species-specific mixed-effects modeling of abundance response using Poisson distribution suggested an inverse correlation of nuttall oak and a direct correlation of cherrybark oak abundance with elevation.However,willow oak(Quercus phellos)abundance was not significantly affected by elevation but was by silt loam soil texture and restoration management techniques.These findings will aid management efforts to reduce the dominance of less desirable species that are prominent under specific environmental conditions and promote the dominance of more desirable species.Ultimately GTR sustainability is increasingly important amid the unpredictable impacts of climate change on the preferred red oak species that are economically,ecologically,and environmentally valuable to the sustaining economy of the local community and managing habitats for wildlife.展开更多
In order to ensure the effective analysis and reconstruction of forests,it is key to ensure the quantitative description of their spatial structure.In this paper,a distance model for the optimal stand spatial structur...In order to ensure the effective analysis and reconstruction of forests,it is key to ensure the quantitative description of their spatial structure.In this paper,a distance model for the optimal stand spatial structure based on weighted Voronoi diagrams is proposed.In particular,we provide a novel methodological model for the comprehensive evaluation of the spatial structure of forest stands in natural mixed conifer-broadleaved forests and the formulation of management decision plans.The applicability of the rank evaluation and the optimal solution distance model are compared and assessed for different standard sample plots of natural mixed conifer-broadleaved forests.The effect of crown width on the spatial structure unit of the trees is observed to be higher than that of the diameter at breast height.Moreover,the influence of crown length is greater than that of tree height.There are nine possible spatial structure units determined by the weighted Voronoi diagram for the number of neighboring trees in the central tree,with an average intersection of neighboring crowns reaching 80%.The rank rating of natural forest sample plots is correlated with the optimal solution distance model,and their results are generally consistent for natural forests.However,the rank rating is not able to provide a quantitative assessment.The optimal solution distance model is observed to be more comprehensive than traditional methods for the evaluation of the spatial structure of forest stands.It can effectively reflect the trends in realistic stand spatial structure factors close to or far from the ideal structure point,and accurately assesses the forest spatial structure.The proposed optimal solution distance model improves the integrated evaluation of the spatial structure of forest stands and provides solid theoretical and technical support for sustainable forest management.展开更多
The rheological behavior of low consistency thermomechanical pulp of Chinese fir harvested by intermediate thinning was analyzed. The results show that the apparent viscosity of pulp changed along with the beating deg...The rheological behavior of low consistency thermomechanical pulp of Chinese fir harvested by intermediate thinning was analyzed. The results show that the apparent viscosity of pulp changed along with the beating degree, pulp consistency and shearing velocity. With the increasing of pulp consistency, the apparent viscosity of pulp increased gradually. Beating degree of pulp had an effect on microstructure of pulp. The apparent viscosity of pulp declined as beating degree of pulp increased, and the apparent viscosity of pulp fell along with the shearing velocity increasing. Based on the results, the rheological models are set up. The models showed that the fluid types of the low consistency pulp could be described as pseudoplastics fluids (non-Newtonian fluids).展开更多
AIM: To assess the prevalence of nutritional disorders in children with inflammatory bowel disease(IBD) in Saudi Arabia.METHODS: The data from a national cohort of children newly diagnosed with IBD between 2003 and 20...AIM: To assess the prevalence of nutritional disorders in children with inflammatory bowel disease(IBD) in Saudi Arabia.METHODS: The data from a national cohort of children newly diagnosed with IBD between 2003 and 2012 were analyzed. The diagnosis of IBD and the differentiation between Crohn's disease(CD) and ulcerative colitis(UC) were confirmed by gastroenterologists according to the standard criteria. The body mass index(BMI) of each child [weight(kg)/height^2(m)] was calculated at the time of diagnosis. The World Health Organization standards and references were used and the BMI for age > +1 and <-2 standard deviation score were used to define overweight and thinness, respectively. Age stratification analysis was performed to investigate any age-related variation in the prevalence of nutritional status between children < 10 years of age and older.RESULTS: There were 374 children from 0.33 to 17 years of age, including 119(32%) children with UC and 255(68%) with CD. All of the children were Saudi nationals, and 68(57%) of the UC and 150(59%) of the CD children were males. A positive history of anorexia at the time of diagnosis was found in 30(25%) patients with UC and 99(39%) patients with CD. The prevalence of thinness was 31%, 35% and 24% in children with IBD, CD and UC, respectively, with a significantly higher prevalence of thinness in children with CD than in children with UC(P = 0.037) only in the age group of 10-17 years(P = 0.030). The prevalence of overweight was 16 %, 15% and 20 % in the children with IBD, CD and UC, respectively, indicating a higher prevalence in UC that was statistically significant only in the age group of 10-17 years(P = 0.020). CONCLUSION: A high proportion of children with IBD presented with overweight instead of the classical underweight. Awareness of this finding is important for patient care.展开更多
AIM:To study the prevalence of functional dyspepsia(FD)(Rome Ⅲ criteria) across eating disorders(ED),obese patients,constitutional thinner and healthy volunteers.METHODS:Twenty patients affected by anorexia nervosa,6...AIM:To study the prevalence of functional dyspepsia(FD)(Rome Ⅲ criteria) across eating disorders(ED),obese patients,constitutional thinner and healthy volunteers.METHODS:Twenty patients affected by anorexia nervosa,6 affected by bulimia nervosa,10 affected by ED not otherwise specified according to diagnostic and statistical manual of mental disorders,4th edition,nine constitutional thinner subjects and,thirtytwo obese patients were recruited from an outpatients clinic devoted to eating behavior disorders.Twentytwo healthy volunteers matched for age and gender were enrolled as healthy controls.All participants underwent a careful clinical examination.Demographic and anthropometric characteristics were obtained from a structured questionnaires.The presence of FD and,its subgroups,epigastric pain syndrome and postprandial distress syndrome(PDS) were diagnosed according to Rome Ⅲ criteria.The intensity-frequency score of broader dyspeptic symptoms such as early satiety,epigastric fullness,epigastric pain,epigastric burning,epigastric pressure,belching,nausea and vomiting were studied by a standardized questionnaire(0-6).Analysis of variance and post-hoc Sheffè tests were used for comparisons.RESULTS:90% of patients affected by anorexia nervosa,83.3% of patients affected by bulimia nervosa,90% of patients affected by ED not otherwise specified,55.6% of constitutionally thin subjects and 18.2% healthy volunteers met the Postprandial Distress Syndrome Criteria(χ 2,P < 0.001).Only one bulimic patient met the epigastric pain syndrome diagnosis.Postprandial fullness intensity-frequency score was significantly higher in anorexia nervosa,bulimia nervosa and ED not otherwise specified groups compared to the score calculated in the constitutional thinner group(4.15 ± 2.08 vs 1.44 ± 2.35,P = 0.003;5.00 ± 2.45vs 1.44 ± 2.35,P = 0.003;4.10 ± 2.23vs 1.44 ± 2.35,P = 0.002,respectively),the obese group(4.15 ± 2.08vs 0.00 ± 0.00,P < 0.001;5.00 ± 2.45vs 0.00 ± 0.00,P < 0.001;4.10 ± 2.23 vs 0.00 ± 0.00,P < 0.001,respectively) and healthy volunteers(4.15 ± 2.08 vs 0.36 ± 0.79,P < 0.001;5.00 ± 2.45 vs 0.36 ± 0.79,P < 0.001;4.10 ± 2.23 vs 0.36 ± 0.79,P < 0.001,respectively).Early satiety intensity-frequency score was prominent in anorectic patients compared to bulimic patients(3.85 ± 2.23 vs 1.17 ± 1.83,P = 0.015),obese patients(3.85 ± 2.23 vs 0.00 ± 0.00,P < 0.001) and healthy volunteers(3.85 ± 2.23 vs 0.05 ± 0.21,P < 0.001).Nausea and epigastric pressure were increased in bulimic and ED not otherwise specified patients.Specifically,nausea intensity-frequencyscore was significantly higher in bulimia nervosa and ED not otherwise specified patients compared to anorectic patients(3.17 ± 2.56 vs 0.89 ± 1.66,P = 0.04;2.70 ± 2.91 vs 0.89 ± 1.66,P = 0.05,respectively),constitutional thinner subjects(3.17 ± 2.56 vs 0.00 ± 0.00,P = 0.004;2.70 ± 2.91 vs 0.00 ± 0.00,P = 0.005,respectively),obese patients(3.17 ± 2.56 vs 0.00 ± 0.00,P < 0.001;3.17 ± 2.56 vs 0.00 ± 0.00,P < 0.001 respectively) and,healthy volunteers(3.17 ± 2.56 vs 0.17 ± 0.71,P = 0.002;3.17 ± 2.56 vs 0.17 ± 0.71,P = 0.001,respectively).Epigastric pressure intensityfrequency score was significantly higher in bulimic and ED not otherwise specified patients compared to constitutional thin subjects(4.67 ± 2.42 vs 1.22 ± 1.72,P = 0.03;4.20 ± 2.21 vs 1.22 ± 1.72,P = 0.03,respectively),obese patients(4.67 ± 2.42 vs 0.75 ± 1.32,P = 0.001;4.20 ± 2.21vs 0.75 ± 1.32,P < 0.001,respectively) and,healthy volunteers(4.67 ± 2.42 vs 0.67 ± 1.46,P = 0.001;4.20 ± 2.21vs 0.67 ± 1.46,P = 0.001,respectively).Vomiting was referred in 100% of bulimia nervosa patients,in 20% of ED not otherwise specified patients,in 15% of anorexia nervosa patients,in 22% of constitutional thinner subjects,and,in 5.6% healthy volunteers(χ 2,P < 0.001).CONCLUSION:PDS is common in eating disorders.Is it mandatory in outpatient gastroenterological clinics to investigate eating disorders in patients with PDS?展开更多
The excessive staminate catkin thinning (emasculation) of proterandrous walnut is an important management measure for improving yield. To improve the excessive staminate catkin thinning efficiency, the model of quad...The excessive staminate catkin thinning (emasculation) of proterandrous walnut is an important management measure for improving yield. To improve the excessive staminate catkin thinning efficiency, the model of quadratic polynomial regression equation and BP artificial neural network was developed. The effects of ethephon, gibberel in and mepiquat on shedding rate of staminate catkin of pro-terandrous walnut were investigated by modeling field test. Based on the modeling test results, the excessive staminate catkin thinning model of quadratic polynomial regression equation and BP artificial neural network was established, and it was validated by field test next year. The test data were divided into training set, vali-dation set and test set. The total 20 sets of data obtained from the modeling field test were randomly divided into training set (17) and validation set (3) by central composite design (quadric rotational regression test design), and the data obtained from the next-year field test were divided into the test set. The topological struc-ture of BP artificial neural network was 3-5-1. The results showed that the pre-diction errors of BP neural network for samples from the validation set were 1.355 0%, 0.429 1% and 0.353 8%, respectively; the difference between the predicted value by the BP neural network and validated value by field test was 2.04%, and the difference between the predicted value by the regression equation and validated value by field test was 3.12%; the prediction accuracy of BP neural network was over 1.0% higher than that of regression equation. The effective combination of quadratic polynomial stepwise regression and BP artificial neural network wil not only help to determine the effect of independent parameter but also improve the prediction accuracy.展开更多
文摘Obesity in childhood or adolescence has been recognized to be a risk factor for the onset of lifestyle-related diseases, not only in healthy children, but also in children with developmental disorders. Therefore, this study was conducted to examine the characteristics of obesity and thinness as assessed by the body fat percentage among children with developmental disorders during certain growth periods. It was also designed to investigate those factors associated with obesity and thinness based on a lifestyle and behavioral questionnaire. The subjects included 260 children from 5 to 18 years old with developmental disorders. The results of the study showed that a decrease in thinness and increase in obesity with ageing exhibited more noticeable trends among those children with mental retardation. The factors associated with obesity in children with developmental disorders were characterized by the dietary content, eating behaviors, and food preferences particular to such children, as well as low physical activity and a family history of obesity. The results of this study suggested the importance of continuous guidance along with family participation in order to improve obesity among children with developmental disorders, while focusing on the characteristics of certain growth periods.
文摘The aim of this study was to investigate the relationship among body image perceptions, a desire for thinness, and dieting behavior in young females in Japan. The subjects were 302 Japanese female university students (age 19.9 ± 1.4 years). An anonymous, self-administered questionnaire survey was conducted between July and August 2011. The questionnaire clarified the subjects’ physical status, perception about personal body shape, desired body shape, the time frame when they first thought about body shape dieting, exercise habits, and eating behaviors. The results revealed that many of the underweight or normal weight subjects perceived themselves as obese, and often the reasons for the perception of obesity were comparisons with others or with themselves in the past. The scores of EAT-26 in those who perceived themselves as obese were higher than the scores in those who did not. Those who perceived themselves as obese had a desire to become slim, were concerned about body shape at an early age, were concerned about dieting, had dieting experience, and were willing to increase daily exercise. These results indicated that incorrect perceptions about body shape have connection to a desire for thinness and dieting behavior.
基金This study was supported by the National Natural Science Foundation of China(Grant No.31870613)Guizhou Province High-level Innovative Talents Training Plan Project(2016)5661.
文摘Light levels determine regeneration in stands and a key concern is how to regulate the light environment of different stand types to the requirements of the understory.In this study,we selected three stands typical in south China(a Cryptomeria japonica plantation,a Quercus acutissima plantation,and a mixed stand of both)and three thinning intensities to determine the best understory light environ-ment for 3-year-old Phoebe bournei seedlings.The canopy structure,understory light environment,and photosynthe-sis and growth indicators were assessed following thin-ning.Thinning improved canopy structure and understory light availability of each stand;species composition was the reason for differences in the understory light environ-ment.Under the same thinning intensity,the mixed stand had the greatest light radiation and most balanced spectral composition.P.bournei photosynthesis and growth were closely related to the light environment;all three stands required heavy thinning to create an effective and sustained understory light environment.In a suitable understory light environment,the efficiency of light interception,absorption,and use by seedlings was enhanced,resulting in a higher carbon assimilation the main limiting factor was stomatal conductance.As a shade-avoidance signal,red/far-red radia-tion is a critical factor driving changes in photosynthesis and growth of P.bournei seedlings,and a reduction increased light absorption and use capacity and height:diameter ratios.The growth advantage transformed from diameter to height,enabling seedlings to access more light.Our findings suggest that the regeneration of shade-tolerant species such as P.bournei could be enhanced if a targeted approach to thinning based on stand type was adopted.
基金the Sino-German Cooperation Forestry Major Scientific Research Project(zdczhz2021ky09)the National Natural Science Foundation of China(31971487 and 42277245).
文摘Thinning is an effective management step for sustainable forest development,yet less attention is paid to the restoration of soil microbiota after thinning.In this study,both abundant and rare soil microbial communities(i.e.,bacterial,fungal),were evaluated under various thinning treatments in a mixed stand of Cunninghamia lanceolata and Sassafras tzumu using Mi Seq sequencing.Thinning did not significantly change either abundant or rare bacterial and fungal community composition,but affected their alpha diversity.The Shannon–Wiener indexes of rare fungal taxa under medium thinning were significantly lower than in the light thinning(P<0.05 level).Xanthobacteraceae dominated the abundant bacterial taxa,and Saitozyma and Mortierlla the abundant fungal taxa.The most common rare bacterial taxa varied;there was no prevalent rare fungal taxa under different thinnings.In addition,soil available nitrogen,total phosphorus,and p H had significant effects on rare bacterial taxa.Nutrients,especially available phosphorus,but not nitrogen,affected abundant and rare soil fungi.The results indicate that soil properties rather than plant factors affect abundant and rare microbial communities in soils of mixed stands.Thinning,through mediating soil properties,influences both abundant and rare bacterial and fungal communities in the mixed C.lanceolata and S.tzumu stand.
基金supported by the National Natural Science Foundation of China (Grant Nos.41701296 and 42277481)the Natural Science Foundation of Gansu Province (GrantNo.22JR5RA058)the Youth Science and Technology Fund Program of Gansu Province (Grant No.22JR5RA087).
文摘Interest in the dynamics of soil respiration(R_(S))in subalpine forest ecosystems is increasing due to their high soil carbon density and potential sensitivity to environmental changes.However,as a principal silvicultural practice,the long-term impacts of thinning on R_(S) and its heterotrophic and autotrophic respiration components(R_(h) and Ra,respectively)in subalpine plantations are poorly understood,espe-cially in winter.A 3-year field observation was carried out with consideration of winter CO_(2) efflux in middle-aged sub-alpine spruce plantations in northwestern China.A trench-ing method was used to explore the long-term impacts of thinning on Rs,Rn and R_(a).Seventeen years after thinning,mean annual Rs,Rn and R_(a) increased,while the contribu-tion of R_(h) to R_(s) decreased with thinning intensity.Thinning significantly decreased winter R,because of the reduction in R_(n) but had no significant effect on Ra.The temperature sensitivity(Q_(10))of R_(h) and R_(a) also increased with thinning intensity,with lower Q_(10) values for R_(h)(2.1-2.6)than for Ra(2.4-2.8).The results revealed the explanatory variables and pathways related to R_(n) and R_(a) dynamics.Thinning increased soil moisture and nitrate nitrogen(NO_(3)^(-)-N),and the enhanced nitrogen and water availability promoted R_(h) and R_(a) by improving fine root biomass and microbial activity.Our results highlight the positive roles of NO_(3)^(-)-N in stimulating R_(s) components following long-term thinning.Therefore,applications of nitrogen fertilizer are not recommended while thinning subalpine spruce plantations from the perspective of reducing soil CO_(2) emissions.The increased Q_(10) values of R_(s) components indicate that a large increase in soil CO_(2) emissions would be expected following thinning because of more pronounced climate warming in alpineregions.
基金supported by the National Key Research and Development Program of China(2016YFD0600201)the National Nonprofit Institute Research Grant of CAF(CAFYBB2017ZB003)+1 种基金the National Natural Science Foundation of China(3187071631670720)。
文摘Understanding the relationship between forest management and water use efficiency(WUE)is important for evaluating forest adaptability to climate change.However,the effects of thinning and understory removal on WUE and its key controlling processes are not well understood,which limits our comprehension of the physiological mechanisms of various management practices.In this study,four forest management measures(no thinning:NT;understory removal:UR;light thinning:LT;and heavy thinning:HT)were carried out in Pinus massoniana plantations in a subtropical region of China.Photosynthetic capacity and needle stable carbon isotope composition(δ^(13)C)were measured to assess instantaneous water use efficiency(WUE_(inst))and long-term water use efficiency(WUE_(i)).Multiple regression models and structural equation modelling(SEM)identified the effects of soil properties and physiological performances on WUE_(inst)and WUE_(i).The results show that WUE_(inst)values among the four treatments were insignificant.However,compared with the NT stand(35.8μmol·mol^(-1)),WUE_(i)values significantly increased to 41.7μmol·mol^(-1)in the UR,50.1μmol·mol^(-1)in the LT and 46.6μmol·mol^(-1)in HT treatments,largely explained by photosynthetic capacity and soil water content.Understory removal did not change physiological performance(needle water potential and photosynthetic capacity).Thinning increased the net photosynthetic rate(A_n)but not stomatal conductance(g_s)or predawn needle water potential(ψ_(pd)),implying that the improvement in water use efficiency for thinned stands was largely driven by radiation interception than by soil water availability.In general,thinning may be an appropriate management measure to promote P.massoniana WUE to cope with seasonal droughts under future extreme climates.
基金financially supported by the Innovation Foundation for Doctoral Program of Forestry Engineering of Northeast Forestry University,grant number:LYGC202117the China Scholarship Council(CSC),grant number:202306600046+1 种基金the Research and Development Plan of Applied Technology in Heilongjiang Province of China,grant number:GA19C006Research and Demonstration on Functional Improvement Technology of Forest Ecological Security Barrier in Heilongjiang Province,grant number:GA21C030。
文摘Background:As is widely known,an increasing number of forest areas were managed to preserve and enhance the health of forest ecosystems.However,previous research on forest management has often overlooked the importance of structure-based.Aims:Our objectives were to define the direction of structure-based forest management.Subsequently,we investigated the relationships between forest structure and the regeneration,growth,and mortality of trees under different thinning treatments.Ultimately,the drivers of forest structural change were explored.Methods:On the basis of 92 sites selected from northeastern China,with different recovery time (from 1 to 15years) and different thinning intensities (0–59.9%) since the last thinning.Principal component analysis (PCA)identified relationships among factors determining forest spatial structure.The structural equation model (SEM)was used to analyze the driving factors behind the changes in forest spatial structure after thinning.Results:Light thinning (0–20%trees removed) promoted forest regeneration,and heavy thinning (over 35% of trees removed) facilitated forest growth.However,only moderate thinning (20%–35%trees removed) created a reasonable spatial structure.While dead trees were clustered,and they were hardly affected by thinning intensity.Additionally,thinning intensity,recovery time,and altitude indirectly improve the spatial structure of the forest by influencing diameter at breast height (DBH) and canopy area.Conclusion:Creating larger DBH and canopy area through thinning will promote the formation of complex forest structures,which cultivates healthy and stable forests.
基金supported by the National Natural Science Foundation of China under Grant No.U2341208.
文摘Designing a sparse array with reduced transmit/receive modules(TRMs)is vital for some applications where the antenna system’s size,weight,allowed operating space,and cost are limited.Sparse arrays exhibit distinct architectures,roughly classified into three categories:Thinned arrays,nonuniformly spaced arrays,and clustered arrays.While numerous advanced synthesis methods have been presented for the three types of sparse arrays in recent years,a comprehensive review of the latest development in sparse array synthesis is lacking.This work aims to fill this gap by thoroughly summarizing these techniques.The study includes synthesis examples to facilitate a comparative analysis of different techniques in terms of both accuracy and efficiency.Thus,this review is intended to assist researchers and engineers in related fields,offering a clear understanding of the development and distinctions among sparse array synthesis techniques.
文摘Management of the Pointe-Noire Forest requires high-performance tools for simulating tree and stand growth and assessing the sustainability of plantations. Modelling the dynamics of even-aged and mono-species stands is a very active research topic. The approaches adopted by researchers vary according to the objectives and species considered: dendrometrical, Eco physiological or architectural. Thanks to the particular nature of these plantations and the trial set-up, it will be possible to explore the various aspects of production, clearly separating the part linked to genetics (three clones tested) from the part linked to the environment (via fertilisation) and the part associated with competition between trees (via planting densities and thinning regimes). This study will make a major contribution to the applicability of the self-thinning line and the RDI (Reineke Density Index) (Reineke, 1933) to fast-growing plantations. This research work will contribute to two points: 1) product diversification, which is a way of coping with international variations in timber markets, and 2) understanding how ecosystems function in exceptionally poor conditions, which will then enable the environmental impacts of the various recommended silvicultural itineraries to be assessed. The results obtained show that competition between trees in a stand of eucalyptus at very high density (10,000 stems/ha) and in two environments of very contrasting fertility is different depending on the clone. The decision on the date of the first thinning with a view to silviculture for timber and energy wood, which aims to ensure sustained and sustainable production of eucalyptus wood in these soils, should be taken between 12 and 14 months. The competition band is strong between 14 and 17 months, when the RDI = 0.8 is double that observed at 12 months.
基金supported by the Applied Technology Research and Development program of Heilongjiang Province(GA19C006)the Innovation Foundation for Doctoral Program of Forestry Engineering of Northeast Forestry University(LYGC202112).
文摘Thinning is a widely used forest management tool but systematic research has not been carried out to verify its eff ects on carbon storage and plant diversity at the ecosystem level.In this study,the eff ect of thinning was assessed across seven thinning intensities(0,10,15,20,25,30 and 35%)in a low-quality secondary forest in NE China over a ten-year period.Thinning aff ected the carbon storage of trees,and shrub,herb,and soil layers(P<0.05).It fi rst increased and then decreased as thinning intensity increased,reaching its maximum at 30%thinning.Carbon storage of the soil accounted for more than 64%of the total carbon stored in the ecosystem.It was highest in the upper 20-cm soil layer.Thinning increased tree species diversity while decreasing shrub and herb diversities(P<0.05).Redundancy analysis and a correlation heat map showed that carbon storage of tree and shrub layers was positively correlated with tree diversity but negatively with herb diversity,indicating that the increase in tree diversity increased the carbon storage of natural forest ecosystems.Although thinning decreased shrub and herb diversities,it increased the carbon storage of the overall ecosystem and tree species diversity of secondary forest.Maximum carbon storage and the highest tree diversity were observed at a thinning intensity of 30%.This study provides evidence for the ecological management of natural and secondary forests and improvement of ecosystem carbon sinks and biodiversity.
基金supported by Natural Science Basic Research Program of Shaanxi(2021JQ-155)National Natural Science Foundation of China(32101511)Chinese Universities Scientific Fund(2452020137 and 2452021073)。
文摘Background:Chinese pine(Pinus tabuliformis Carr.)is one of the major afforestation species in northern China and plays a key role in restoring forest ecosystems and preserving soil and water.However,most Chinese pine plantations are experiencing ecological problems such as the low diversity of understory plants and difficulty in natural regeneration.Thinning has been widely used to maintain and improve a variety of forest ecosystem services from plantations.To date,however,few studies have been conducted to systematically determine the effects of thinning on understory plant diversity and the regeneration of Chinese pine in plantations.Methods:We conducted a literature search,and selected 22 publications covering a total of 83 treatments related to thinning effects on the species richness of understory plants and 15 publications covering a total of 43 treatments related to thinning effects on the regeneration of Chinese pine,in tree plantations of northern China.The data from the literature were synthesized and evaluated with meta-analysis approach to determine the treatment effects.Results:Compared with the control stands,thinning increased the species richness of shrubs and herbs by an average of 25.3%and 26.5%,respectively.While the varying thinning intensities all had significantly positive effects on the species richness of understory plants,only moderate thinning(30%–50%)had a positive effect on the density of regenerating seedlings and saplings of Chinese pine(60.2%).The species richness of understory plants was greatest after 14 years of thinning with an increase of 36.3%,whereas the density of regenerating Chinese pine seedlings and saplings reached a maximum after≥11 years of thinning with an increase of 76.5%,compared to that of the unthinned stands.Thinning in the half-mature plantations had the greatest effects on the understory shrub richness(44.1%)and the density of regenerating Chinese pine seedlings and saplings(86.5%).Both single and multiple thinning were found to significantly promote the species richness of understory plants and the density of regenerating Chinese pine seedlings and saplings,and the positive effects of thinning were greater in areas with a humidity index(HI)<30 than in areas with an HI≥30.In general,age group,planting density and recovery time were prominent factors affecting the species richness of understory plants,whereas the slope,HI and recovery time were the dominant controls of the density of regenerating Chinese pine seedlings and saplings,indicating differential effects of thinning on the species richness of understory plants and the regeneration capacity of Chinese pine in plantations.Conclusion:Thinning appears to be a feasible management measure to improve the understory plant diversity and regeneration capacity of Chinese pine in plantations.We postulate that moderate thinning in half-mature forest stands with an HI<30 can help effectively promote the species diversity of understory plants and the natural regeneration of Chinese pine,thereby maintaining a more resilient stand structure and the development of Chinese pine plantations.
基金funded by the National Key R&D Program of China(2017YFC0504103)Project for Applied Technology Research and Development in Heilongjiang Province(GA19C006).
文摘To explore how to respond to seasonal freeze–thaw cycles on forest ecosystems in the context of climate change through thinning,we assessed the potential impact of thinning intensity on carbon cycle dynamics.By varying the number of temperature cycles,the eff ects of various thinning intensities in four seasons.The rate of mass,litter organic carbon,and soil organic carbon(SOC)loss in response to temperature variations was examined in two degrees of decomposition.The unfrozen season had the highest decomposition rate of litter,followed by the frozen season.Semi-decomposed litter had a higher decomposition rate than undecomposed litter.The decomposition rate of litter was the highest when the thinning intensity was 10%,while the litter and SOC were low.Forest litter had a good carbon sequestration impact in the unfrozen and freeze–thaw seasons,while the converse was confi rmed in the frozen and thaw seasons.The best carbon sequestration impact was identifi ed in litter,and soil layers under a 20–25%thinning intensity,and the infl uence of undecomposed litter on SOC was more noticeable than that of semi-decomposed litter.Both litter and soil can store carbon:however,carbon is transported from undecomposed litter to semi-decomposed litter and to the soil over time.In summary,the best thinning intensity being 20–25%.
基金Financial and logistic support for this research was provided by Five Oaks Ag Research&Education Center(DS18849)University of Arkansas Division of Agriculture(PR02276)University of Arkansas at Monticello.Funding support was provided by U.S.Department of Agriculture,National Institute of Food and Agriculture,McIntire-Stennis Capacity Grant(2729 YR21-25 and ARK02594).
文摘Elevation gradients within forested wetlands have long been recognized for their role in defining species composition through factors such as hydrology and soil characteristics.Greentree reservoirs(GTRs)are leveeimpounded tracts of bottomland hardwood forest flooded throughout the winter months to provide habitat for overwintering waterfowl.Artificial flooding of GTRs alters the forest composition due to flood frequency,depth,and duration in combination with slight changes in topography.To evaluate the effect of elevation gradients,soil properties,and management techniques in the overstory species composition and red oak(Quercus spp.)species abundance,we inventoried 662 plots across 12 independent GTRs in eastern Arkansas.In the lower elevations ranging from 50.98 to 54.99 m above sea level,the importance value index(IVI)was highest for nuttall oak(Quercus texana)and overcup oak(Quercus lyrata),whereas IVI shifted to cherrybark oak(Quercus pagoda)in the higher elevations ranging from 54.99 to 58.00 m.Alpha diversity did not differ by elevation gradient,soil property,or management technique within GTRs.Beta diversity,using non-metric multi-dimensional scaling(NMDS)analysis,indicated site-specific variability significantly correlated with the environmental predictors,including elevation(R^(2)=0.57),easting(R^(2)=0.47),soil texture(R^(2)=0.21),and pH(R^(2)=0.12).Red oak species-specific mixed-effects modeling of abundance response using Poisson distribution suggested an inverse correlation of nuttall oak and a direct correlation of cherrybark oak abundance with elevation.However,willow oak(Quercus phellos)abundance was not significantly affected by elevation but was by silt loam soil texture and restoration management techniques.These findings will aid management efforts to reduce the dominance of less desirable species that are prominent under specific environmental conditions and promote the dominance of more desirable species.Ultimately GTR sustainability is increasingly important amid the unpredictable impacts of climate change on the preferred red oak species that are economically,ecologically,and environmentally valuable to the sustaining economy of the local community and managing habitats for wildlife.
基金funded by National Key Research and development project(2022YFD2201001)。
文摘In order to ensure the effective analysis and reconstruction of forests,it is key to ensure the quantitative description of their spatial structure.In this paper,a distance model for the optimal stand spatial structure based on weighted Voronoi diagrams is proposed.In particular,we provide a novel methodological model for the comprehensive evaluation of the spatial structure of forest stands in natural mixed conifer-broadleaved forests and the formulation of management decision plans.The applicability of the rank evaluation and the optimal solution distance model are compared and assessed for different standard sample plots of natural mixed conifer-broadleaved forests.The effect of crown width on the spatial structure unit of the trees is observed to be higher than that of the diameter at breast height.Moreover,the influence of crown length is greater than that of tree height.There are nine possible spatial structure units determined by the weighted Voronoi diagram for the number of neighboring trees in the central tree,with an average intersection of neighboring crowns reaching 80%.The rank rating of natural forest sample plots is correlated with the optimal solution distance model,and their results are generally consistent for natural forests.However,the rank rating is not able to provide a quantitative assessment.The optimal solution distance model is observed to be more comprehensive than traditional methods for the evaluation of the spatial structure of forest stands.It can effectively reflect the trends in realistic stand spatial structure factors close to or far from the ideal structure point,and accurately assesses the forest spatial structure.The proposed optimal solution distance model improves the integrated evaluation of the spatial structure of forest stands and provides solid theoretical and technical support for sustainable forest management.
基金This study was sponsored by the Research Funding for Outstanding Young University Faculty of China Ministry of Education (No. 2001-39), Fujian Provincial Innovation Fundation for Young Science and Technology Talents (No. 2004J012), and the National Natural Science Funda-tion of China (No. 30571461)
文摘The rheological behavior of low consistency thermomechanical pulp of Chinese fir harvested by intermediate thinning was analyzed. The results show that the apparent viscosity of pulp changed along with the beating degree, pulp consistency and shearing velocity. With the increasing of pulp consistency, the apparent viscosity of pulp increased gradually. Beating degree of pulp had an effect on microstructure of pulp. The apparent viscosity of pulp declined as beating degree of pulp increased, and the apparent viscosity of pulp fell along with the shearing velocity increasing. Based on the results, the rheological models are set up. The models showed that the fluid types of the low consistency pulp could be described as pseudoplastics fluids (non-Newtonian fluids).
基金Supported by The Deanship of Scientific Research at King Saud University through Research GroupNo.RG-1436-007
文摘AIM: To assess the prevalence of nutritional disorders in children with inflammatory bowel disease(IBD) in Saudi Arabia.METHODS: The data from a national cohort of children newly diagnosed with IBD between 2003 and 2012 were analyzed. The diagnosis of IBD and the differentiation between Crohn's disease(CD) and ulcerative colitis(UC) were confirmed by gastroenterologists according to the standard criteria. The body mass index(BMI) of each child [weight(kg)/height^2(m)] was calculated at the time of diagnosis. The World Health Organization standards and references were used and the BMI for age > +1 and <-2 standard deviation score were used to define overweight and thinness, respectively. Age stratification analysis was performed to investigate any age-related variation in the prevalence of nutritional status between children < 10 years of age and older.RESULTS: There were 374 children from 0.33 to 17 years of age, including 119(32%) children with UC and 255(68%) with CD. All of the children were Saudi nationals, and 68(57%) of the UC and 150(59%) of the CD children were males. A positive history of anorexia at the time of diagnosis was found in 30(25%) patients with UC and 99(39%) patients with CD. The prevalence of thinness was 31%, 35% and 24% in children with IBD, CD and UC, respectively, with a significantly higher prevalence of thinness in children with CD than in children with UC(P = 0.037) only in the age group of 10-17 years(P = 0.030). The prevalence of overweight was 16 %, 15% and 20 % in the children with IBD, CD and UC, respectively, indicating a higher prevalence in UC that was statistically significant only in the age group of 10-17 years(P = 0.020). CONCLUSION: A high proportion of children with IBD presented with overweight instead of the classical underweight. Awareness of this finding is important for patient care.
文摘AIM:To study the prevalence of functional dyspepsia(FD)(Rome Ⅲ criteria) across eating disorders(ED),obese patients,constitutional thinner and healthy volunteers.METHODS:Twenty patients affected by anorexia nervosa,6 affected by bulimia nervosa,10 affected by ED not otherwise specified according to diagnostic and statistical manual of mental disorders,4th edition,nine constitutional thinner subjects and,thirtytwo obese patients were recruited from an outpatients clinic devoted to eating behavior disorders.Twentytwo healthy volunteers matched for age and gender were enrolled as healthy controls.All participants underwent a careful clinical examination.Demographic and anthropometric characteristics were obtained from a structured questionnaires.The presence of FD and,its subgroups,epigastric pain syndrome and postprandial distress syndrome(PDS) were diagnosed according to Rome Ⅲ criteria.The intensity-frequency score of broader dyspeptic symptoms such as early satiety,epigastric fullness,epigastric pain,epigastric burning,epigastric pressure,belching,nausea and vomiting were studied by a standardized questionnaire(0-6).Analysis of variance and post-hoc Sheffè tests were used for comparisons.RESULTS:90% of patients affected by anorexia nervosa,83.3% of patients affected by bulimia nervosa,90% of patients affected by ED not otherwise specified,55.6% of constitutionally thin subjects and 18.2% healthy volunteers met the Postprandial Distress Syndrome Criteria(χ 2,P < 0.001).Only one bulimic patient met the epigastric pain syndrome diagnosis.Postprandial fullness intensity-frequency score was significantly higher in anorexia nervosa,bulimia nervosa and ED not otherwise specified groups compared to the score calculated in the constitutional thinner group(4.15 ± 2.08 vs 1.44 ± 2.35,P = 0.003;5.00 ± 2.45vs 1.44 ± 2.35,P = 0.003;4.10 ± 2.23vs 1.44 ± 2.35,P = 0.002,respectively),the obese group(4.15 ± 2.08vs 0.00 ± 0.00,P < 0.001;5.00 ± 2.45vs 0.00 ± 0.00,P < 0.001;4.10 ± 2.23 vs 0.00 ± 0.00,P < 0.001,respectively) and healthy volunteers(4.15 ± 2.08 vs 0.36 ± 0.79,P < 0.001;5.00 ± 2.45 vs 0.36 ± 0.79,P < 0.001;4.10 ± 2.23 vs 0.36 ± 0.79,P < 0.001,respectively).Early satiety intensity-frequency score was prominent in anorectic patients compared to bulimic patients(3.85 ± 2.23 vs 1.17 ± 1.83,P = 0.015),obese patients(3.85 ± 2.23 vs 0.00 ± 0.00,P < 0.001) and healthy volunteers(3.85 ± 2.23 vs 0.05 ± 0.21,P < 0.001).Nausea and epigastric pressure were increased in bulimic and ED not otherwise specified patients.Specifically,nausea intensity-frequencyscore was significantly higher in bulimia nervosa and ED not otherwise specified patients compared to anorectic patients(3.17 ± 2.56 vs 0.89 ± 1.66,P = 0.04;2.70 ± 2.91 vs 0.89 ± 1.66,P = 0.05,respectively),constitutional thinner subjects(3.17 ± 2.56 vs 0.00 ± 0.00,P = 0.004;2.70 ± 2.91 vs 0.00 ± 0.00,P = 0.005,respectively),obese patients(3.17 ± 2.56 vs 0.00 ± 0.00,P < 0.001;3.17 ± 2.56 vs 0.00 ± 0.00,P < 0.001 respectively) and,healthy volunteers(3.17 ± 2.56 vs 0.17 ± 0.71,P = 0.002;3.17 ± 2.56 vs 0.17 ± 0.71,P = 0.001,respectively).Epigastric pressure intensityfrequency score was significantly higher in bulimic and ED not otherwise specified patients compared to constitutional thin subjects(4.67 ± 2.42 vs 1.22 ± 1.72,P = 0.03;4.20 ± 2.21 vs 1.22 ± 1.72,P = 0.03,respectively),obese patients(4.67 ± 2.42 vs 0.75 ± 1.32,P = 0.001;4.20 ± 2.21vs 0.75 ± 1.32,P < 0.001,respectively) and,healthy volunteers(4.67 ± 2.42 vs 0.67 ± 1.46,P = 0.001;4.20 ± 2.21vs 0.67 ± 1.46,P = 0.001,respectively).Vomiting was referred in 100% of bulimia nervosa patients,in 20% of ED not otherwise specified patients,in 15% of anorexia nervosa patients,in 22% of constitutional thinner subjects,and,in 5.6% healthy volunteers(χ 2,P < 0.001).CONCLUSION:PDS is common in eating disorders.Is it mandatory in outpatient gastroenterological clinics to investigate eating disorders in patients with PDS?
基金Supported by Key Science and Technology Program of Shanxi Province,China(002023)~~
文摘The excessive staminate catkin thinning (emasculation) of proterandrous walnut is an important management measure for improving yield. To improve the excessive staminate catkin thinning efficiency, the model of quadratic polynomial regression equation and BP artificial neural network was developed. The effects of ethephon, gibberel in and mepiquat on shedding rate of staminate catkin of pro-terandrous walnut were investigated by modeling field test. Based on the modeling test results, the excessive staminate catkin thinning model of quadratic polynomial regression equation and BP artificial neural network was established, and it was validated by field test next year. The test data were divided into training set, vali-dation set and test set. The total 20 sets of data obtained from the modeling field test were randomly divided into training set (17) and validation set (3) by central composite design (quadric rotational regression test design), and the data obtained from the next-year field test were divided into the test set. The topological struc-ture of BP artificial neural network was 3-5-1. The results showed that the pre-diction errors of BP neural network for samples from the validation set were 1.355 0%, 0.429 1% and 0.353 8%, respectively; the difference between the predicted value by the BP neural network and validated value by field test was 2.04%, and the difference between the predicted value by the regression equation and validated value by field test was 3.12%; the prediction accuracy of BP neural network was over 1.0% higher than that of regression equation. The effective combination of quadratic polynomial stepwise regression and BP artificial neural network wil not only help to determine the effect of independent parameter but also improve the prediction accuracy.