期刊文献+
共找到985篇文章
< 1 2 50 >
每页显示 20 50 100
Extended finite element-based cohesive zone method for modeling simultaneous hydraulic fracture height growth in layered reservoirs 被引量:1
1
作者 Lei Yang Baixi Chen 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第8期2960-2981,共22页
In this study,a fully coupled hydromechanical model within the extended finite element method(XFEM)-based cohesive zone method(CZM)is employed to investigate the simultaneous height growth behavior of multi-cluster hy... In this study,a fully coupled hydromechanical model within the extended finite element method(XFEM)-based cohesive zone method(CZM)is employed to investigate the simultaneous height growth behavior of multi-cluster hydraulic fractures in layered porous reservoirs with modulus contrast.The coupled hydromechanical model is first verified against an analytical solution and a laboratory experiment.Then,the fracture geometry(e.g.height,aperture,and area)and fluid pressure evolutions of multiple hydraulic fractures placed in a porous reservoir interbedded with alternating stiff and soft layers are investigated using the model.The stress and pore pressure distributions within the layered reservoir during fluid injection are also presented.The simulation results reveal that stress umbrellas are easily to form among multiple hydraulic fractures’tips when propagating in soft layers,which impedes the simultaneous height growth.It is also observed that the impediment effect of soft layer is much more significant in the fractures suppressed by the preferential growth of adjoining fractures.After that,the combined effect of in situ stress ratio and fracturing spacing on the multi-fracture height growth is presented,and the results elucidate the influence of in situ stress ratio on the height growth behavior depending on the fracture spacing.Finally,it is found that the inclusion of soft layers changes the aperture distribution of outmost and interior hydraulic fractures.The results obtained from this study may provide some insights on the understanding of hydraulic fracture height containment observed in filed. 展开更多
关键词 Hydraulic fracturing Layered reservoir Simultaneous height growth In situ stress Fracture spacing Extended finite element method(XFEM) Cohesive zone method(CZM)
下载PDF
Study on height growth model of Pinus koraiensis 被引量:1
2
作者 邓红兵 郝占庆 王庆礼 《Journal of Forestry Research》 SCIE CAS CSCD 2001年第3期192-194,210,共3页
Growth model is an efficient way to study growing process of some factors of plants quantitatively. Height growth of Korean pine (Pinus koraiensis) was studied by using Hyperbola equation, Logistic equation, Richards ... Growth model is an efficient way to study growing process of some factors of plants quantitatively. Height growth of Korean pine (Pinus koraiensis) was studied by using Hyperbola equation, Logistic equation, Richards equation with three parameters, and Richards equation with four parameters in this paper. The results showed that Richards equation with four parameters was the most suitable and could be turned into other theoretical equations when some parameters were given different value. The maximum height of trees could be given in advance when using Richards equation with four parameters, and it was even more corresponding to reality. In addition, a height growth model with real height of fixed age as a parameter was discussed in this paper. This kind of growth model could be used to calculate height growth of a given tree effectively. 展开更多
关键词 Korean pine height growth MODEL
下载PDF
Comparative Analyses of Height Growth Velocities of School Boys in South Korea and Japan in the Past 50 Years
3
作者 Hiroshi Mori 《Food and Nutrition Sciences》 2020年第7期659-668,共10页
The paper compares the height growth velocities of male schoolchildren in South Korea and Japan over the period 1961-2018. Growth in height was measured with the same birth cohorts, not by comparing mean height of asc... The paper compares the height growth velocities of male schoolchildren in South Korea and Japan over the period 1961-2018. Growth in height was measured with the same birth cohorts, not by comparing mean height of ascending ages in the same year. Starting from a lower economic base and mean height in the 1960s, high school males aged 17 in South Korea became 3 cm taller in mean height than their Japanese peers in the mid-2000s versus 2 - 3 cm shorter in the 1960s through 1970s. Children in Japan ceased to grow taller by the end of the 1980s, not because they quit taking more animal-sourced foods, meat and milk, but because they had drastically steered away from fruit and vegetables in their diets since the end of the 1970s. Having largely converged economically with Japan, South Korean children ceased to grow any taller in the mid-2000s. More importantly, it was discovered in this study that successive cohorts in South Korea started to fall gradually but steadily in height growth velocity from 1<sup><span style="font-family:Verdana;font-size:12px;">st</span></sup><span style="font-family:Verdana;font-size:12px;"> graders in middle school, aged 12 years to 3</span><sup><span style="font-family:Verdana;font-size:12px;">rd</span></sup><span style="font-family:Verdana;font-size:12px;"> graders in high school, </span><span style="font-family:Verdana;">and </span><span style="font-family:Verdana;">aged 17 years, to be once again 3 cm below their Japanese peers in the early-2010s. Analysis of Korea Household Expenditure Surveys classified by age groups of household head, decomposed by the author, revealed that children under 20 years of age in South Korea began to steer away from fruit and, particularly, vegetables in their at-home consumption in the mid-1990s, to average only 15% of the level of older adults in their 50s in the mid-2010s. These results lend supports to the importance of fruit and vegetables as determinants in height and its growth velocities in two genetically similar nations over time and stages of economic growth.</span> 展开更多
关键词 height School Boys growth Velocities Birth Cohort South Korea JAPAN Vegetables and Fruit
下载PDF
Study of the Effects of Glucocorticoid on Growth and Adult Final Height in Children with Primary Nephrotic Syndrome
4
作者 Fazhan Zhong Miao Zhang Yan Gao 《Open Journal of Nephrology》 2024年第1期1-9,共9页
Objective: To analyze the epidemiological characteristics of growth, as well as factors associated with growth retardation in children with primary nephrotic syndrome (PNS), and to investigate the effect of glucocorti... Objective: To analyze the epidemiological characteristics of growth, as well as factors associated with growth retardation in children with primary nephrotic syndrome (PNS), and to investigate the effect of glucocorticoid (GC) use duration on growth retardation in these children. Methods: Clinical and laboratory data of 353 PNS children treated at our hospital from July 2014 to June 2015 were collected through the medical record management system. Height, weight, and GC usage were recorded. Follow-up assessments were conducted in August 2022 for the original group, recording height, weight, and GC usage. Height and weight were evaluated using standard deviation scores (SDS). Categorical data were analyzed using chi-square test while continuous measurement data were analyzed using t-test or rank-sum test. Linear regression was used to assess the association between two single independent variables, and logistic regression analysis was used to screen for risk factors related to growth retardation in children with PNS. Results: Among the 353 PNS children enrolled in this study, male-to-female ratio of 2.64:1 (256 males vs 97 females). A total of 119 children exhibited growth retardation, incidence rate of 33.71%. The duration of GC usage among those with growth retardation was significantly longer compared to those without it (762.81 ± 934.50 days vs 263.77 ± 420.49 days;p Conclusion: PNS children treated with GC have a high incidence of growth retardation, and a high proportion of short stature in adulthood, especially in children with growth retardation in childhood, most of them have short stature after grown up. Time of GC usage is a risk factor for growth retardation in children with PNS. 展开更多
关键词 Primary Nephrotic Syndrome GLUCOCORTICOID CHILDREN growth Retardation Adult height
下载PDF
Height/Length and Weight Growth Curves and Growth References of Children Aged 0 - 7 in Chongqing by GAMLSS
5
作者 Qian Chen Jiaxiu Liu +1 位作者 Kaocong Tian Zhaohai Liu 《Health》 2020年第2期86-98,共13页
Aim: Using the generalised additive model for location, the scale and shape (GAMLSS), the standard of height (length), weight and percentage curve of children were formulated to understand the growth law in Chongqing ... Aim: Using the generalised additive model for location, the scale and shape (GAMLSS), the standard of height (length), weight and percentage curve of children were formulated to understand the growth law in Chongqing and to provide a reference for clinical and preventive health care work of paediatrics in West China. Methods: Data were collected from the health clinic dataset of children aged 0 - 7 years in the Department of Child Health Care of a Third-Class A hospital in Chongqing from 2010 to 2017. By applying the GAMLSS technology and taking D(μ, σ, ν, τ) as the specific distribution form, BCT as the link function, P-spline function and cubic splines function as the smoothing function, the unit value of age-specific standard deviation of height (length) and weight were obtained, and the percentile map was drawn. Results: Based on the principle of minimum AIC and SBC values, BCT distribution was chosen as the model of the link function. Fitting results of height (length) and weight parameters of boys and girls, standard deviation tables of age and percentile curves were obtained. Conclusions: This study was an exploration of using GAMLSS method to establish a reference value range in the field of children’s growth and development in China. It could supplement the relevant data of Chongqing area for Reference standard for growth and development of children under 7 years of age in China, and also provide a reference for the rational diagnosis of children’s short stature and malnutrition in Chongqing. 展开更多
关键词 CHILDREN height WEIGHT growth Curve GAMLSS
下载PDF
Mining Applicable Elite Alleles of Growth Duration, Plant Height and Panicle Number per Plant by Conditional QTL Mapping in Japonica Rice 被引量:2
6
作者 Jian-hua JIANG Qi-bing ZHAO +4 位作者 Qiang-ming LIU Lan CHEN Fu-long CHEN Bao-jian QIAO De-lin HONG 《Rice science》 SCIE 2011年第3期196-203,共8页
Unconditional and conditional QTL mapping were conducted for growth duration (GD), plant height (PH) and effective panicle number per plant (PN) using a recombinant inbred line (RIL) population derived from a cross be... Unconditional and conditional QTL mapping were conducted for growth duration (GD), plant height (PH) and effective panicle number per plant (PN) using a recombinant inbred line (RIL) population derived from a cross between two japonica rice varieties Xiushui 79 and C Bao. The RIL population consisted of 254 lines was planted in two environments, Nanjing and Sihong, Jiangsu Province, China. Results showed that additive effects were major in all of QTLs for GD, PH and PN detected by the two methods, and the epistatic effects explained a small proportion of phenotypic variation. No interactions were detected between additive QTL and environment, and between epistatic QTL pairs and environment. After growth duration was adjusted to an identical level, RM80-160bp was detected as an applicable elite allele for PN, with an additive effect of 0.71. When effective panicle number per plant was adjusted to an identical level, RM448-240bp was detected as an applicable elite allele for GD, with an additive effect of 4.64. After plant height was adjusted to an identical level, RM80-160bp was detected as an applicable elite allele for PN, with an additive effect of 0.62, and RM448-240bp was detected as an applicable elite allele for GD, with an additive effect of 3.89. These applicable elite alleles could be used to improve target traits without influencing the other two traits. 展开更多
关键词 japonica rice growth duration plant height effective panicle number per plant unconditional QTL mapping conditional QTL mapping recombinant inbred line
下载PDF
Effects of Lithological Characters on the Growth of Cunninghamia lanceolata
7
作者 刘映良 谢双喜 丁贵杰 《Agricultural Science & Technology》 CAS 2009年第6期94-96,107,共4页
Objective The aim was to reveal relationship between lithological character soil and productivity of Cunninghamia lanceolata and lay a foundation for systemic management of C. lanceolata fast-growing and high yield pl... Objective The aim was to reveal relationship between lithological character soil and productivity of Cunninghamia lanceolata and lay a foundation for systemic management of C. lanceolata fast-growing and high yield plantation. Method By using experimental ecology method and variance analysis, the biomass and growth of planting eleven years' C. lanceolata on the soils with six different lithologicel characters were studied. Result The effects of soils with six different lithological characters on the height, diameter growth and biomass of C. lanceolata were different, in which the growth order of C. lanceolata was: Feldspathic quartzy sandstone ( average height 523. 270 cm, average diameter 4.720 cm, average individual biomass 5.059kg) 〉 Basalt ( average height 511. 570 cm, average diameter 4.650 cm, average individual biomass 4.848 kg) 〉 Quartzy sandstone 〉 Blastopsammite 〉 The Quarternary Period red clay 〉 Coal-series siliceous sand-shale, and the difference was smaller between the last two lithological characters. Conclusion Feldspathic quartzy sandstone and Basalt are beneficial to C. lanceolata. 展开更多
关键词 Cunninghamia lanceolata Lithological character height growth Diameter growth BIOMASS
下载PDF
Effect of first thinning and pruning on the individual growth of Pinus patula tree species 被引量:4
8
作者 Edward Missanjo Gift Kamanga-Thole 《Journal of Forestry Research》 SCIE CAS CSCD 2015年第4期827-831,共5页
The effect of first thinning and pruning on height, diameter at breast height (DBH), and volume growth was studied in individual trees of Pinus patula Schiede and Deppe in Chongoni Plantation, using four plots for t... The effect of first thinning and pruning on height, diameter at breast height (DBH), and volume growth was studied in individual trees of Pinus patula Schiede and Deppe in Chongoni Plantation, using four plots for thinning trials. Each of the plots was 0.5 ha and subjected to one of the fol- lowing silvicultural treatments: first thinning and pruning, first thinning and no pruning, pruning and no thinning, and control (no pruning and no thinning). The silvicultural treatments were randomized in four replicates. Fourteen years after planting, the following parameters were measured including total height, DBH, and volume. The highest DBH and volume growth was observed in thinning and pruning, while the highest growth in height was observed where there was pruning and no thinning. Clearly, both thinning and pruning are an important manage- ment option in pine species plantations in Malawi to maximize the increase in volume productivity. 展开更多
关键词 Pinus patula Thinning and pruning Diameter growth height growth VOLUME
下载PDF
Growth and ecophysiology of seedlings of Podocarpus falcatus in plantations of exotic species and in a natural montane forest in Ethiopia 被引量:1
9
作者 Desalegn Tadele Masresha Fetene 《Journal of Forestry Research》 SCIE CAS CSCD 2013年第1期29-35,共7页
The potential role of exotic tree plantations in facilitating successional processes on degraded areas was evaluated in southern Ethiopia by comparing seedling characteristics, transpiration and photosynthetic perform... The potential role of exotic tree plantations in facilitating successional processes on degraded areas was evaluated in southern Ethiopia by comparing seedling characteristics, transpiration and photosynthetic performance of Podocarpus falcatus seedlings in Eucalyptus plantation, Pinus plantation, adjacent natural forest and clear-felled plantation site. P. falcatus seedlings exhibited differences in architecture between Eucalyptus and Pinus plantations. They had higher leaf area, shorter internode length and greater number of lateral branches in Eucalyptus plantation. At similar vapor pressure deficit (VPD), P. falcatus transpired much less than E. saligna, especially at higher VPDs. Analysis of fluorescence parameters in the leaves showed no significant differences in the level of dark-adapted and light-adapted fluorescence yield (Fv/Fm and ΔF/Fm′, respectively), electron transport rate (ETR) and nonphotochemical quenching (NPQ) among seedlings grown inside plantations and adjacent natural forest, indicating similar photosynthetic performance. Nevertheless, there was evidence of photoinhibition in P. falcatus in the clear-felled site which had low fluorescence yield but high values of NPQ as protection from photoamage. The light response curves of ETR, NPQ and ΔF/Fm′ showed similar light saturation behavior among the seedlings grown inside plantations and natural forest and suggested a sequence of light-adapted to shade-adapted behavior in Natural forest 〉 Eucalyptus plantation 〉 Pinus plantation. The results show the structural flexibility, better water-use and adaptability of P. falcatus in its use of the understory environment of plantation species. 展开更多
关键词 chlorophyll fluorescence height growth lateral growth light response curves TRANSPIRATION
下载PDF
Response of photosynthesis,growth,and acorn mass of pedunculate oak to diff erent levels of nitrogen in wet and dry growing seasons 被引量:1
10
作者 Krunoslav Sever Saša Bogdan ŽeljkoŠkvorc 《Journal of Forestry Research》 SCIE CAS CSCD 2023年第1期167-176,共10页
The objective was to examine the effects of optimal leaf nitrogen levels>2.0%and suboptimal levels<2.0%,nitrogen nutrition on net photo synthetic rate,stem diameter increment,height growth increment and acorn ma... The objective was to examine the effects of optimal leaf nitrogen levels>2.0%and suboptimal levels<2.0%,nitrogen nutrition on net photo synthetic rate,stem diameter increment,height growth increment and acorn mass of pedunculate oak during 2010 in the absence of drought stress and during 2011 under the impact of moderate drought stress.According to the results,moderate drought stress significantly reduced net photo synthetic rate,stem diameter increment and height growth increment,while acorn mass was not affected.Suboptimal nitrogen nutrition significantly reduced the net photo synthetic rate and stem diameter increment only in the wet year,acorn mass in both wet and dry years,while height growth increment was not significantly reduced by suboptimal nitrogen nutrition in either year.The results indicate that optimal nitrogen levels can stimulate photo synthetic rate and stem diameter increment of pedunculate oak only in the absence of moderate drought stress.Moreover,the results show that moderate drought stress is a more dominant stressor for photosynthesis and growth of pedunculate oak than suboptimal nitrogen nutrition,while for acorn development,it is the more dominant stressor. 展开更多
关键词 Quercus robur L. Drought stress Net photosynthic rate Stem diameter increment height growth increment Acorn mass
下载PDF
Impacts of Primo MAXX Growth Regulator on the Growth of Bermuda Grass
11
作者 李战胜 张海娟 陈勇 《Agricultural Science & Technology》 CAS 2010年第9期180-182,共3页
[Objective] The aim was to investigate the effects of Primo MAXX growth regulator on growth of Bermuda grass,explore appropriate application concentration of Primo MAXX on Bermuda grass,and provide basis for the appli... [Objective] The aim was to investigate the effects of Primo MAXX growth regulator on growth of Bermuda grass,explore appropriate application concentration of Primo MAXX on Bermuda grass,and provide basis for the application of Primo MAXX in Bermuda meadow.[Method]The height,leaf colour and the aerial part's fresh weight of Bermuda grass treated with different concentrations were researched using single factor random block test.[Result]Primo MAXX application effectively reduced the height in all treatment without significant difference;appropriate application of Primo MAXX can enrich the color;and 35 days after application,Bermuda grass roots were become thicker.[Conclusion]The application of Primo MAXX with effective dose of 150-300 g/hm2 on Bermuda grass in southern China is more appropriate. 展开更多
关键词 Primo MAXX Bermuda grass growth height Leaf color Fresh weight of aerial part
下载PDF
GROWTH OF MONGOLIAN OAK
12
作者 赵惠勋 王传宽 刘滨辉 《Journal of Northeast Forestry University》 SCIE CAS CSCD 1994年第1期10-17,共8页
The height fast growing period of oak seedling (Quercus mongolica) was between 25 to 30 years old but the diameter varied greatly. The maximum diurnal height increment of the investigated oak tree reached 3. 3 cm, but... The height fast growing period of oak seedling (Quercus mongolica) was between 25 to 30 years old but the diameter varied greatly. The maximum diurnal height increment of the investigated oak tree reached 3. 3 cm, but at daytime it was much greater than at night. The oak trees usually sprouted twice and even treble in the growing season. In natural oak stands. the volume rarely exceeded 200 m3/hm2 and the mean volume increment was only about 2 m3/hm2 展开更多
关键词 Mongolian oak Grand period of growth Seasonal growth Diurnal height growth Stand growth
下载PDF
Crohn's disease and growth deficiency in children and adolescents 被引量:8
13
作者 Marco Gasparetto Graziella Guariso 《World Journal of Gastroenterology》 SCIE CAS 2014年第37期13219-13233,共15页
Nutritional concerns, linear growth deficiency, and delayed puberty are currently detected in up to 85% of patients with Crohn's disease(CD) diagnosed at childhood. To provide advice on how to assess and manage nu... Nutritional concerns, linear growth deficiency, and delayed puberty are currently detected in up to 85% of patients with Crohn's disease(CD) diagnosed at childhood. To provide advice on how to assess and manage nutritional concerns in these patients, a Medline search was conducted using "pediatric inflammatory bowel disease", "pediatric Crohn's disease", "linear growth","pubertal growth", "bone health", and "vitamin D" as key words. Clinical trials, systematic reviews, and metaanalyses published between 2008 and 2013 were selected to produce this narrative review. Studies referring to earlier periods were also considered if the data was relevant to our review. Although current treatment strategies for CD that include anti-tumor necrosis factor-αtherapy have been shown to improve patients' growth rate, linear growth deficiencies are still common. In pediatric CD patients, prolonged diagnostic delay, high initial activity index, and stricturing/penetrating typeof behavior may cause growth deficiencies(in weight and height) and delayed puberty, with several studies reporting that these patients may not reach an optimal bone mass. Glucocorticoids and inflammation inhibit bone formation, though their impact on skeletal modeling remains unclear. Long-term control of active inflammation and an adequate intake of nutrients are both fundamental in promoting normal puberty. Recent evidence suggests that recombinant growth factor therapy is effective in improving short-term linear growth in selected patients, but is of limited benefit for ameliorating mucosal disease and reducing clinical disease activity. The authors conclude that an intense initial treatment(taking a "top-down" approach, with the early introduction of immunomodulatory treatment) may be justified to induce and maintain remission so that the growth of children with CD can catch up, ideally before puberty. Exclusive enteral nutrition has a key role in inducing remission and improving patients' nutritional status. 展开更多
关键词 Bone health Enteral nutrition growth height Pediatric inflammatory bowel disease Pediatric Crohn's disease Linear growth Pubertal growth Vitamin D Weight loss
下载PDF
Growth of Scotch Pine (Pinus sylvestris L.) Plantation in Northern Mongolia 被引量:2
14
作者 S. Gerelbaatar N. Baatarbileg 《Journal of Agricultural Science and Technology(B)》 2011年第8期1205-1210,共6页
The growth of Scotch pine in Northem Mongolian plantations was studied to determine variation in heights, diameters at breast height (DBH), and main and annual volume increment of stem volumes in relation to plantat... The growth of Scotch pine in Northem Mongolian plantations was studied to determine variation in heights, diameters at breast height (DBH), and main and annual volume increment of stem volumes in relation to plantation age. The study was conducted in the Tujyin Nars region, where six plantations ranging from 9 to 25 years old were selected for the assessment. Results indicate that the growth of Scotch pine on the plantations did not vary by site, and that more intensive annual increment in height was observed on Scotch pine plantations between the ages of 8 to 15 years. The amount of annual height increment and radial growth improves regularly up to 9 to 11 years of age and then the intensity of annual increment declines due to competition for light and nutrients. Additionally, there was a reduction in the number of trees per ha. Results suggest that it is necessary to implement forestry thinning which aimed at improving growth of Scotch pine on the plantations because intensity of annual increment in height and diameter reduces regularly due to restriction of growing condition. 展开更多
关键词 SEEDLING annual increment height and radial growth volume survival.
下载PDF
Physical Growth of Children in Urban,Suburban and Rural China's Mainland:A Study of 20 Years' Change 被引量:3
15
作者 LI Hui ZONG XinNan +1 位作者 ZHANG Jing ZHU ZongHan 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2011年第1期1-11,共11页
Objective To describe secular trends on physical growth of children in China during the year of 1985‐2005 and to analyze the urban‐suburban‐rural difference and its change. Methods The measurements of height, weigh... Objective To describe secular trends on physical growth of children in China during the year of 1985‐2005 and to analyze the urban‐suburban‐rural difference and its change. Methods The measurements of height, weight and chest circumference obtained from two serial national cross‐sectional surveys for children aged 0 to 7 years in China were used to analyze the secular trends, and the growth differences among urban, suburban and rural children were compared. Results The average weight and height for both boys and girls from urban, suburban and rural areas have significantly increased in most age groups during the past 20 years; The average chest circumference increased slightly, ranging from 0.0 to 2.0 cm. From 1985 to 2005, the urban‐suburban difference in height had become smaller, and that in weight showed similar trend for children under 3 years old but became larger after 3 years old; the suburban‐rural difference both in height and weight became larger after 6 months old. The increment per decade in height was the greatest in the suburban group while the greatest increment in weight was the urban group. Conclusion Positive secular trends were observed among urban, suburban and rural areas in Chinese children under 7 years old during the 1980s and the 2000s, reflecting a rapid socio‐economic development in China. 展开更多
关键词 growth Secular trends height WEIGHT Chest circumference
下载PDF
Study on the Influence of Climatic Change on Pasture Growth in Inner Mongolia Grassland 被引量:1
16
作者 Li Xinghua Liu Xiurong +1 位作者 Cao Yanfang Sun Xiaolong 《Meteorological and Environmental Research》 CAS 2014年第5期43-47,52,共6页
Through analyzing statistically metrological observation data from 1971 to 2010 and pasture data from 1983 to 2012 at 6 animal husbandry meteorological testing stations of Inner Mongolia grassland, the conclusions wer... Through analyzing statistically metrological observation data from 1971 to 2010 and pasture data from 1983 to 2012 at 6 animal husbandry meteorological testing stations of Inner Mongolia grassland, the conclusions were drawn. Those were that annual average temperature rose in a straight line in Inner Mongolia grassland, and the increase rates of annual average temperature in meadow steppe and typical steppe were 0.40 and 0.34 ℃/10 a respectively. Annual rainfall had 10-year cyclical characteristics, and precipitation in the 1990s was the most but reduced significantly after 2000. Climate experienced the cold wet -cold dry -warm wet -warm dry periods. Warm and dry climate made the average heights of pasture in meadow steppe and typical steppe of Inner Mongolia cut down 2.4 and 9.3 cm in nearly 12 years than that in the 1990s; the average coverage of herbage decreased by 11% and 13%; the average hay yields reduced by 1 019.8 and 671.4 kg/hm^2. 展开更多
关键词 Climatic change Pasture growth period Pasture height Grass coverage Hay yield China
下载PDF
Pre-sowing treatments for improved germination and growth of two rare native species of Bangladesh
17
作者 M.A.Hossain K.S.Islam +2 位作者 N.Rajasree M.K.Hossain M.S.Alam 《Journal of Forestry Research》 SCIE CAS CSCD 2018年第5期1277-1282,共6页
Pre-sowing treatments are expected to increase seed germination.This evaluates response to pre-sowing treatments and the growth performance of two native and rare tree species,Garuga pinnata Roxb.and Vitex glabrata R.... Pre-sowing treatments are expected to increase seed germination.This evaluates response to pre-sowing treatments and the growth performance of two native and rare tree species,Garuga pinnata Roxb.and Vitex glabrata R.Br.The hard seed coats were treated by rubbing with sand paper,nail clipping,and immersion in water and acid(H_2SO_4).Results indicate that G.pinnata showed a 90% germination rate and 30% germination energy when seed coats were nicked with a nail clipper.Rubbing with sand paper was the best pre-sowing treatment for V.glabrata,resulting a 80% germination rate and 30% germination energy.G.pinnata and V.glabrata seedlings from seeds soaked 24h in water resulted in maximum heights and collar diameters.These were significantly higher(at p〈0.05) than those of other treatments.The results indicate that scarification or nicking of seeds may have some negative impacts on seedling growth.Therefore,it is difficult to recommend a pre-sowing treatment of seeds for achieving both maximum germination and good early seedling growth. 展开更多
关键词 GERMINATION Early seedling growth height Native species Garuga pinnata Vitex glabrata
下载PDF
Characteristics Analysis of Extreme Circulation at 500 hPa of Height Field in Eurasian Region during Recent 20 Years
18
作者 Quan Shan 《Meteorological and Environmental Research》 CAS 2013年第11期12-15,21,共5页
[ Objective] The research aimed to analyze extreme circulation characteristics at 500 hPa of height field in Eurasian region in recent 20 years. [ Method ] Based on NCEP/NCAR reanalysis daily data at 500 hPa of height... [ Objective] The research aimed to analyze extreme circulation characteristics at 500 hPa of height field in Eurasian region in recent 20 years. [ Method ] Based on NCEP/NCAR reanalysis daily data at 500 hPa of height field from 1961 to 2009 of Eurasia (15° -80° N, 40° -150° E), seasonal and monthly change situations of extreme circulation in Eurasia were studied by the method of climatologically equally likely intervals ( CE- Ll). [Result] Growth rate of extremely low circulation increased in Eurasia in the last 20 years, but the rise amplitude was smaller. In the middle of China and Mongolia, grow rate change of extremely low circulation was the smallest. The growth rates of extremely high circulation in spring, au- tumn and winter gradually decreased as latitude rose. The maximum growth rate of extremely high circulation in summer was in Qinghai -Tibet Plat- eau, which corresponded with the climate characteristics of summer subtropical high going northward and then retreating southward. By contrasting the growth rates of extremely low and high circulation, it was clear that the growth rate of high circulation was higher than that of the low circulation. [Conusion] The research could be as a reference for studying change characteristics of the extreme climate event in China. 展开更多
关键词 Extreme circulation 500 hPa of height field CELL growth rate China
下载PDF
Indoor smoke and prenatal and childhood growth:The role of (gestational) age
19
作者 Rakesh Ghosh 《World Journal of Clinical Pediatrics》 2013年第4期31-35,共5页
Growth at birth and during infancy predicts several outcomes in the immediate future as well as in the long term. Weight and height are commonly used surrogates of growth, however, infants and young children are const... Growth at birth and during infancy predicts several outcomes in the immediate future as well as in the long term. Weight and height are commonly used surrogates of growth, however, infants and young children are constantly growing unlike adults. Hence, weight and height alone are insufficient measures of growth if the time component is not associated with them. Recent studies have investigated the relationship between indoor air pollution and growth using height and weight. In this commentary, I have argued using a directed acyclic graph, that a causal association between indoor pollution exposure and growth at birth cannot be established unless birth weight is adjusted for gestational age. Furthermore, to make any causal inference between growth during the first few years of life and indoor exposure, in addition to age standardization, studies must also account for fetal growth to discount any continuation of prenatal effects, which may be in the causal pathway. A careful consideration is warranted from future studies investigating these relationships. 展开更多
关键词 BIOFUEL Coal SMOKE Wood SMOKE BIRTH weight FETAL growth height
下载PDF
Estimating Pinus palustris tree diameter and stem volume from tree height,crown area and stand-level parameters 被引量:15
20
作者 C.A.Gonzalez-Benecke Salvador A.Gezan +3 位作者 Lisa J.Samuelson Wendell P.Cropper Daniel J.Leduc Timothy A.Martin 《Journal of Forestry Research》 SCIE CAS CSCD 2014年第1期43-52,共10页
Accurate and efficient estimation of forest growth and live biomass is a critical element in assessing potential responses to forest management and environmental change. The objective of this study was to develop mode... Accurate and efficient estimation of forest growth and live biomass is a critical element in assessing potential responses to forest management and environmental change. The objective of this study was to develop models to predict longleaf pine tree diameter at breast height (dbh) and merchantable stem volume (V) using data obtained from field measurements. We used longleaf pine tree data from 3,376 planted trees on 127 permanent plots located in the U.S. Gulf Coastal Plain region to fit equations to predict dbh and V as functions of tree height (H) and crown area (CA). Prediction of dbh as a function of H improved when CA was added as an additional independent variable. Similarly, predic- tions of V based on H improved when CA was included. Incorporation of additional stand variables such as age, site index, dominant height, and stand density were also evaluated but resulted in only small improvements in model performance. For model testing we used data from planted and naturally-regenerated trees located inside and outside the geographic area used for model fitting. Our results suggest that the models are a robust alternative for dbh and V estimations when H and CA are known on planted stands with potential for naturally-regenerated stands, across a wide range of ages. We discuss the importance of these models for use with metrics derived from remote sensing data. 展开更多
关键词 Longleaf pine diameter-height relationships crown area individual-tree stem volume growth and yield modeling
下载PDF
上一页 1 2 50 下一页 到第
使用帮助 返回顶部