Reevaluating health metrics:Unraveling the limitations of disabilityadjusted life years as an indicator in disease burden assessment

In 1993,the World Bank released a global report on the efficacy of health promotion,introducing the disability-adjusted life years(DALY)as a novel indicator.The DALY,a composite metric incorporating temporal and qualitative data,is grounded in preferences regarding disability status.This review delineates the algorithm used to calculate the value of the proposed DALY synthetic indicator and elucidates key methodological challenges associated with its application.In contrast to the quality-adjusted life years approach,derived from multi-attribute utility theory,the DALY stands as an independent synthetic indicator that adopts the assumptions of the Time Trade Off utility technique to define Disability Weights.Claiming to rely on no mathematical or economic theory,DALY users appear to have exempted themselves from verifying whether this indicator meets the classical properties required of all indicators,notably content validity,reliability,specificity,and sensitivity.The DALY concept emerged primarily to facilitate comparisons of the health impacts of various diseases globally within the framework of the Global Burden of Disease initiative,leading to numerous publications in international literature.Despite widespread adoption,the DALY synthetic indicator has prompted significant methodological concerns since its inception,manifesting in inconsistent and non-reproducible results.Given the substantial diffusion of the DALY indicator and its critical role in health impact assessments,a reassessment is warranted.This reconsideration is imperative for enhancing the robustness and reliability of public health decisionmaking processes.

Characteristics of the HIV/AIDS Epidemic among People Aged≥50 Years in China during 2018–2021

Objective This study aimed to determine the current epidemiological status of PLWHA aged≥50 years in China from 2018 to 2021.It also aimed to recommend targeted interventions for the prevention and treatment of HIV/AIDS in elderly patients.Methods Data on newly reported cases of PLWHA,aged≥50 years in China from 2018 to 2021,were collected using the CRIMS.Trend tests and spatial analyses were also conducted.Results Between 2018 and 2021,237,724 HIV/AIDS cases were reported among patients aged≥50 years in China.The main transmission route was heterosexual transmission(91.24%).Commercial heterosexual transmission(CHC)was the primary mode of transmission among males,while non-marital non-CHC([NMNCHC];60.59%)was the prevalent route in women.The proportion of patients with CHC decreased over time(Z=67.716,P<0.01),while that of patients with NMNCHC increased(Z=153.05,P<0.01).The sex ratio varied among the different modes of infection,and it peaked at 17.65 for CHC.The spatial analysis indicated spatial clustering,and the high-high clustering areas were mainly distributed in the southwestern and central-southern provinces.Conclusion In China,PLWHA,aged≥50 years,were predominantly infected through heterosexual transmission.The primary modes of infection were CHC and NMNCHC.There were variations in the sex ratio among different age groups,infected through various sexual behaviors.HIV/AIDS cases exhibited spatial clustering.Based on these results,the expansion of HIV testing,treatment,and integrated behavioral interventions in high-risk populations is recommended to enhance disease detection in key regions.

Effect of a Nutrition Education Intervention on Food Safety Knowledge, Attitudes and Practices of Mothers of Children under 5 Years in the Peri-Urban Areas of Bobo-Dioulasso: Before and after Study

Background: This study assessed the effect of a nutrition education intervention. This intervention aimed to improve the knowledge, attitudes, and practices of mothers on food safety in the peri-urban areas of Bobo-Dioulasso in Burkina Faso. Methods: A total of 243 mothers of children under 5 years in the peri-urban of Bobo-Dioulasso were administered the FAO questionnaire for food safety knowledge, attitudes, and practices assessment during two cross-sectional surveys, before and after the intervention, in January and October 2017. The intervention included two components consisting of a theoretical phase (counselling and discussion) and cooking demonstrations implemented for ten months. To account for the before-and-after design of the study, the McNemar’s test was used to assess the effect of the intervention on food safety KAP of mothers of children under 5 years. Results: The mean age of mothers was 29 ± 6.2 years and 50.6% of them were between 20 and 29 years old. One for knowledge (cooking thoroughly with, p-value = 0.0001) and another for attitudes (perceived benefits of reheating leftovers before eating them, p-value = 0.0001), significantly increased after the intervention. In terms of food safety practices, all the indicators (cleaning of dirty surfaces, plates and utensils and storage of perishable foods) significantly increased (all p = 0.0001 Conclusion: This study provided some evidence of an effective nutrition education intervention for improving maternal KAP on food safety for their child’s feeding.

Factors Associated with Mortality in Children Aged 1 Month to 15 Years Hospitalized in the Pediatric Ward of the Kalaban-Coro Reference Health Center: Cross-Sectional Study

Introduction: Infant and child mortality is a worldwide concern, but developing countries such as Mali are more affected. The aim of this study was to investigate morbidity and factors associated with mortality in children aged 1 month to 15 years. Methodology: This was a cross-sectional study which took place from January 1 to December 31, 2020 covering children aged 1 month to 15 years hospitalized at the Kalaban-Coro CSRéf. Data were entered into Excel and analyzed using SPSS version 20 software. Results: Five hundred children aged 1 months to 15 years were included. The age range 1 to 5 years (53.6%) and male sex (58.2%) were the most represented. Malaria (72.2%), acute respiratory infections (6.2%) and diarrhea/dehydration (3%) were the main morbidities. Mortality was estimated at 10.6%, and the two main causes of death were malaria (56.6%) and acute respiratory infections (7.54%). Univariate analysis revealed a statistically significant association between the dependent variable (death) and age (p Conclusion: This study confirms the high rate of infant and child morbidity and mortality in our health facilities. Strengthening human resources and intensifying behavior-change communication can help reverse the trend.

Quality-adjusted life years and surgical waiting list:Systematic review of the literature

BACKGROUND The quality-adjusted life year(QALY)is a metric that is increasingly used today in the field of health economics to evaluate the value of different medical treatments and procedures.Surgical waiting lists(SWLs)represent a pressing problem in public healthcare.The QALY measure has rarely been used in the context of surgery.It would be interesting to know how many QALYs are lost by patients on SWLs.AIM To investigate the relationship between QALYs and SWLs in a systematic review of the scientific literature.METHODS The study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement.An unlimited search was carried out in PubMed,updated on January 19,2024.Data on the following variables were investigated and analyzed:Specialty,country of study,procedure under study,scale used to measure QALYs,the use of a theoretical or real-life model,objectives of the study and items measured,the economic value assigned to the QALY in the country in question,and the results and conclusions published.RESULTS Forty-eight articles were selected for the study.No data were found regarding QALYs lost on SWLs.The specialties in which QALYs were studied the most in relation to the waiting list were urology and general surgery,with 15 articles each.The country in which the most studies of QALYs were carried out was the United States(n=21),followed by the United Kingdom(n=9)and Canada(n=7).The most studied procedure was organ transplantation(n=39),including 15 kidney,14 liver,5 heart,4 lung,and 1 intestinal.Arthroplasty(n=4),cataract surgery(n=2),bariatric surgery(n=1),mosaicplasty(n=1),and septoplasty(n=1)completed the surgical interventions included.Thirty-nine of the models used were theoretical(the most frequently applied being the Markov model,n=34),and nine were real-life.The survey used to measure quality of life in 11 articles was the European Quality of Life-5 dimensions,but in 32 articles the survey was not specified.The willingness-to-pay per QALY gained ranged from$100000 in the United States to€20000 in Spain.CONCLUSION The relationship between QALYs and SWLs has only rarely been studied in the literature.The rate of QALYs lost on SWLs has not been determined.Future research is warranted to address this issue.

A Study on the Pedagogical Application of Chinese New Year Culture in International Chinese Language Education

Culture teaching is an inseparable part of International Chinese Language Education,and it has great significance in international Chinese language teaching.Students can enhance their interest in Chinese language learning and improve their learning effect through understanding the excellent traditional Chinese culture,at the same time,culture teaching can help to disseminate the Chinese culture and promote the development of a multicultural world.Taking the teaching of Chinese New Year culture as an example,we analyze the current teaching materials involving Chinese New Year culture with high popularity and acceptance,put forward effective teaching methods matching the feasibility of teaching Chinese New Year culture,and then present the specific teaching design of Chinese New Year culture,in order to provide references for the teaching of culture in International Chinese Language Education.

Analysis of the Spirit of Struggle in the New Era Based on General Secretary Xi Jinping’s New Year’s Greetings in the Past Decade

In order to realize the national rejuvenation,General Secretary Xi Jinping attaches great importance to the spiritual strength of struggle,and has repeatedly advocated that all people should exalt the spirit of strive on different occasions.According to his New Year’s greetings since 2014,Xi Jinping has illustrated the connotation of the spirit of enterprising,the necessity of carrying forward and the requirements for practicing the spirit of struggle from different perspectives,pointing out that all Chinese must keep in mind both domestic and international situations,strive in unity,work creative and industrious with the enthusiasm of seizing every minute,catch the opportunity and solve the problem,make substantial progress on the new journey to construct China into a great modern socialist country in all respects.

The influence of Nitrogen Nutrition on Starch Accumulation in the Process of Tuber Development in Autumn Solanum tuberosum L.

Taking two varieties, high and low starch content respectively, as tested materials, experiments were conducted to study the effects of nitrogen fertilizer in different levels on tuber starch accumulation characteristics under autumn planting condition, and thus to provide technical support in optimized planting techniques of autumn potato. The results showed that during tuber development the changes in concentrations of total starch, amylopectin and amylose were ＂S＂ shaped curve un-der different nitrogen fertilizer treatments, in line with the Logistic equation Y=K/（1＋ae-bT）, but both starch accumulation intensity and the time reaching to maximum ac-cumulation intensity were not exactly the same in different nitrogen fertilizer levels so is it with different varieties. Furthermore, high starch concentration variety ‘XS-1’, the largest accumulation of strength of amylase was the lower in the middle fertil-ization and higher in low and high fertilization treatments. The contents of amy-lopectin, total starch were first increasing and then dropping with the amount of ni-trogen increasing. To low starch concentration variety ‘XS-2’, with nitrogen fertilizer content increase, the largest accumulation of strength was reducing in amylose, but was rising in amylopectin and changed from rising to fal ing in total starch. The time reaching to maximum accumulation strength in amylose and total starch changed from increasing to decreasing and amylopectin kept declining.

Morphological changes of silver and bighead carp in the Yangtze River over the past 50 years

Multivariate analysis was adopted to analyze 30 morphometrical characteristics of 121 one-year-old juvenile silver carp （Hypophthalmichthys molitrix） and bighead carp （Aristichthys nobilis） bred during the 1950s （＂the former population＂） and 2008 （＂the current population＂） and collected from the middle reach of the Yangtze River. The average discriminant accuracies of the former and current silver and bighead carp population were 94.2% and 98.0%, respectively. Discriminant analysis also revealed that significant differences in morphology occurred between the former and current populations of both carp in overall characteristics. One-way analysis of variance indicated that between former and current populations, silver carp showed highly significant differences （P0.01） in twelve of their characteristics and significant differences （P0.05） in eight of their characteristics, while bighead carp showed highly significant differences （P0.01） in eight of their characteristics and significant differences （P0.05） in eight of their characteristics. Six head morphology variables of the current silver and bighead carp were significantly or highly significantly larger than the former populations; fourteen characteristics of silver carp and ten characteristics of bighead carp of the current populations, mainly reflecting truck and tail morphology, were significantly or very significantly smaller than the former populations. Our results indicate that silver and bighead carp have developed a larger head and smaller truck and tail during the last 50 years. Due to such morphological changes, it seems apparent that the heads of these fish species need to be considered in regards to human diets, particularly in relation to economic and nutritious value.

Review of Two Years of Surgical Activities of the General Surgery Department of the Reference Health Center of Commune I of Bamako Mali

The objectives of this work were to evaluate the surgical activities carried out in the general surgery department of the Reference Health Center of Commune I of Bamako, to describe the sociodemographic characteristics of the operated patients, to determine the main pathologies encountered and to evaluate qualitatively the result of the treatment. In order to improve performance, and the quality of care, and to identify common pathologies in the surgical department, we undertook a retrospective study on surgical activities from January 2009 to December 2010. At the end of this study, out of 474 men and 187 women (equal sex ratio 2.53);we were able to determine the frequency of surgical pathologies. Farmers, housewives and pupils/students were the most represented with 25.9% respectively;20% and 13.3%. The most frequently observed pathologies were wall hernia (44.8%), prostate adenoma (12%) and acute appendicitis (10.5%). The average length of hospitalization was 3.43 days. Infectious complications affected 25 patients (3.8% of cases) and a death rate of 0.45% (i.e. 3 patients). The average cost of care was 53,500 FCFA. Indeed, the reality of surgical practice in health centers was not the same because of the level of skills of practicing surgeons.

Introducing a 2nd Universal Space-Time Constant Can Explain the Observed Age of the Universe and Dark Energy

The purpose of this paper is to introduce new theoretical concepts as opposed to accepting the existence of dark entities, such as dark energy. This research sought to introduce a 2nd universal space-time constant, besides having a finite speed constant (speed of light in vacuum c). A finite universal age constant b is introduced. Namely, this paper shows that the changes in the Earth’s anomalistic year duration over time support the hypothesis of the age of the universe correlating with a maximum number of orbital revolutions constant. Neglecting the gravitational influence of other cosmological entities in the proximity of the Earth, the constant maximum number of revolutions is herewith determined solely by the Earth’s orbital revolutions around the Sun. The value of the universal age constant b is calculated to be around 13.8 billion orbital revolutions, derived out of an equation related to the changes in the Earth’s anomalistic year duration over time and the so-called Hubble tension. The above-mentioned calculated value b correlates well with the best fit to measured data of the cosmic microwave background radiation (CMBR) by the Planck spacecraft, the age of the observed universe is measured to be approximately 13.787 ± 0.020 billion years (2018 final data release). Developing a theory with this 2nd universal space-time constant b, being covariant with respect to the Lorentz transformations when time spans are large, gives results such as: A confirmation of the measured CMBR value of 13.787 ± 0.020 billion years. Correlating well with the observed expansion rate of the universe (dark energy). The universe’s expansion accelerating over the last four to five billion years.

Nowcasting and forecasting global aging and cancer burden:analysis of data from the GLOBOCAN and Global Burden of Disease Study

Objective:To analyze the impact of global population aging on cancer epidemiology,with a focus on the incidence and mortality rates among individuals aged 60 years and above.Methods:We utilized open-source data,retrieving population age estimates from the United Nations Population Division website.The GLOBOCAN 2020 database provided estimates for cancer cases and deaths in 2020 and 2040,while the Global Burden of Disease 2019 database supplied estimates of new cancer cases worldwide from 2000 to 2019.Inclusion criteria considered individuals aged 60 years and over,focusing on the top five deadliest cancers.The cohort-component method was employed for population prediction,with age-specific incidence and mortality rates estimated for 2020 used to forecast the cancer burden.Results:In 2021,the global population aged over 60 years accounted for 13.7%,with Europe/North America and Australia/New Zealand having the highest proportions.The older population is predicted to reach 19.2%by 2040.In 2020,of the 19.3 million new cancer cases worldwide,64%occurred in individuals aged 60 and above,contributing to 71.3%of cancer-related deaths.The five most common cancer sites were the lung,colorectum,prostate,breast,and stomach.Cancer incidence and deaths are projected to rise significantly among older indi-viduals,reaching 20.7 million new cases and 12.7 million deaths by 2040.Older age,tobacco use,dietary factors,alcohol consumption,and high body mass index(BMI)were identified as major risk factors for various cancers in this demographic.Conclusions:This study reveals a significant rise in cancer incidence and mortality among the elderly due to global population aging.The urgency for targeted interventions in cancer prevention,screening,and treatment for older individuals is emphasized.Despite acknowledged limitations,these findings contribute valuable insights to inform strategies for managing cancer in the elderly amidst evolving demographic trends.

Relationship between gene expression and the accumulation of catechin during spring and autumn in tea plants (Camellia sinensis L.)

The tea plant(Camellia sinensis L.)is an important commercial crop with remarkably high catechin concentrations.Tea is popular worldwide given the plant's health benefits.Catechins are the main astringent substance in tea and are synthesized mainly via the phenylpropanoid pathway.In this study,eight cultivars of tea plants harvested both in spring and autumn were used to investigate differences in catechin concentrations by using high-performance liquid chromatography.The expression levels of genes associated with catechin biosynthesis were investigated using reverse transcription-quantitative polymerase chain reaction.The results indicated that the total catechin(TC)concentrations were significantly higher in tea plants harvested in autumn than in those harvested in spring,based on higher concentrations of epigallocatechin(EGC)in autumn tea(P<0.01).The expression of the genes phenylalanine ammonia-lyase(PAL),flavanone 3-hydroxylase(F3H),flavonoid 3′,5′-hydroxylase(F3′5′H),dihydroflavonol 4-reductase(DFR),and anthocyanidin synthase(ANS)is closely related to the TC content of tea plants in both spring and autumn.Positive correlations between PAL,cinnamate 4-hydroxylase(C4H),F3H,and DFR expression and EGC accumulation in autumn tea were identified,with correlation coefficients of 0.710,0.763,0.884,and 0.707,respectively.A negative correlation between ANS expression level and EGC concentrations in tea plants harvested in spring was noted(r=−0.732).Additionally,negative correlations between F3H and ANS expression levels and the catechin content were identified in spring tea,whereas the correlations were positive in autumn tea.Significant differences in the F3H and ANS expression levels between spring and autumn tea indicate that F3H and ANS are potentially key genes affecting catechin accumulation in tea plants.

The prevalence of vision impairment and refractive error in 3654 first year students at Tianjin Medical University

AIM：To determine the prevalence of vision impairment（VI）and refractive error in first year university students at the Tianjin Medical University.METHODS：This is a cross-sectional observational cohort study of VI and refractive error among first year university students at the Tianjin Medical University.The first year university students were involved in this study and were given a detailed questionnaire including age,birth date,and spectacle wearing history.A standardized ophthalmologic examination including visual acuity（VA）,slit-lamp examination,non-cycloplegic auto-refraction,objective refraction,fundus photography,and examination of their spectacles were recorded.RESULTS：A total of 3654 participants were included in this study.Totally 3436（94.03%） individuals had VI in this population.Totally 150（4.10%） individuals had VI due to ocular disease,including amblyopia,congenital cataract,retinal atrophy or degeneration,strabismus,congenital nystagmus,refractive surgery orthokeratology.Totally 3286（89.93%） subjects had VI due to refractive error.Only 218（5.97%） students were emmetropia.Moreover,refractive error was the main cause for the VI（95.63%）.Totally 3242（92.52%） students were myopia and the prevalence of mild,moderate,and high myopia subgroup was 27.05%,44.35%,and 21.26% respectively.Totally 44（1.29%） subjects were hyperopic.The rates of uncorrected visual acuity（UCVA）,presenting visual acuity（PVA）and best corrected visual acuity（BCVA）which better than 20/20 in both eyes were 5.65%,22.32% and 82.13% respectively.The rates of correction,under correction and well correction in myopia subjects were 82.73%,84.39% and 15.61%,respectively. CONCLUSION：We present a high prevalence of refractive errors and high rates of under correction refractive error among first year university students.These results may help to promote vision protection work in young adults.

The Interdecadal Variation Characteristics of Arctic Sea Ice Cover-ENSO-East Asian Monsoon and Their Interrelationshipat Quasi-Four Years Time Scale

Interdecadal and quasi-four years variation characterstics of Arctic sea for cover, ENSO and East Asian monsoon index(EAMI) are analyzed based on Singular Spectrum Analys. (SSA), lead-lag correlation and EOF for the past four decades. Results show that the Arctic sea for cover decreased in the early 1970s, several years earlier than that of global SSTA increase in the mid 1970s, which indicates that recent warming over the Northern Hemisphere firstly begins in the Arctic region in the 1970s. Great change of the East Asian monsoon intensity from stronger to weaker in summer (from weaker to stronger in winter) took place in the mid 1970s response to the abrupt modulation of SSTA particularly in the tropical eastern Pacific.Focus on the quasi-four years oscillation,close relationship is found among the sea ice cover, ENSO and EAMI based on lead-lag correlation. In which, the correlation coefficient reaches its maximum when the index of NINO3 SSTA variation takes 6 and 9 months lead of the western Pacific subtropical high and sea for cover index in Section-Ⅲ. Their interaction can be explained in the framework of asymmetric Walker circulation anomaly and Western Pacific Northern Pole (WPN) teleconnection pattern in the context of quasi-four years oscillation.

Observed characteristics of atmospheric ducts over the South China Sea in autumn

The observed characteristics of lower atmospheric ducts over the South China Sea(SCS) were analyzed based on Global Position Systerm(GPS) radiosonde data collected four times daily during autumn open cruises from 2006 to 2012.Duct occurrence,thickness,and strength over the SCS were about 40%,150-m thick,and 8 M units,respectively,which were larger than during the summer monsoon period.Most ducts occurred at heights <1 500 m and these ducts easily trap electromagnetic wave clusters with wavelengths <2 m.Diurnal variation of the SCS ducts appeared evident.They occurred more often at midnight at higher altitudes(about 1 100 m),with a thickest layer of about 145 m and less frequently during the evening at lower altitudes(about 800 m),with a thinnest layer of about 125 m.Moreover,ducts during the daytime at a mean height of about 900 m,with the greatest strength of about 10 M units.Furthermore,all duct variables observed over the SCS in autumn decreased from north to south.These findings are useful not only in the design of radar and communication systems,but also for evaluating possible effects of anomalous propagation on meteorological radar and military applications.

Characterization of longshore currents in southern East China Sea during summer and autumn

Current characteristics and vertical variations during summer and autumn in the southern East China Sea were investigated by measuring current profile, tide, wind, and wave data for 90 d from July 28 to October 25, 2015. Our results are:(1) The current was mainly a(clockwise) rotating flow, displaying reciprocating flow characteristics,and vertically the current directions were the same throughout the vertical profile.(2) The horizontal current speed was strongest during August(summer) with an average speed of 51.8 cm/s. The average current speeds during spring tides were highest in August and weakest in September, with speeds of 59.9 and 42.8 cm/s,respectively.(3) Considerable differences exist in average current speeds in different layers and seasons. The highest average current speeds were found in the middle–upper layers in August and in the middle–lower layers in September and October.(4) The residual current speed was highest in August, when the speed was 12.5–47.1 cm/s,whereas the vertical average current speed was 34.3 cm/s. The depth-averaged residual current speeds in September and October were only 50% of that in August, and the residual current direction gradually rotated in a counter-clockwise direction from the lower to surface layers.(5) Typhoon waves had a significant influence on the currents, and even affected the middle and lower water layers at depths of >70.0 m. Our results showed that the currents are controlled by the dynamic interplay of the Taiwan Warm Current, incursion of the Kuroshio Current onto the continental shelf, and monsoonal changes.

Characteristics of Temperature Change in China over the Last 2000 years and Spatial Patterns of Dryness/Wetness during Cold and Warm Periods

This paper presents new high-resolution proxies and paleoclimatic reconstructions for studying climate changes in China for the past 2000 years. Multi-proxy synthesized reconstructions show that temperature variation in China has exhibited significant 50–70-yr, 100–120-yr, and 200–250-yr cycles. Results also show that the amplitudes of decadal and centennial temperature variation were 1.3℃ and 0.7℃, respectively, with the latter significantly correlated with long-term changes in solar radiation, especially cold periods, which correspond approximately to sunspot minima. The most rapid warming in China occurred over AD 1870–2000, at a rate of 0.56°± 0.42℃（100 yr）^（-1）; however, temperatures recorded in the 20 th century may not be unprecedented for the last 2000 years, as data show records for the periods AD 981–1100 and AD1201–70 are comparable to the present. The ensemble means of dryness/wetness spatial patterns in eastern China across all centennial warm periods illustrate a tripole pattern： dry south of 25°N, wet from 25°–30°N, and dry to the north of 30°N. However, for all centennial cold periods, this spatial pattern also exhibits a meridional distribution. The increase in precipitation over the monsoonal regions of China associated with the 20 th century warming can primarily be attributed to a mega El Nino–Southern Oscillation and the Atlantic Multidecadal Oscillation. In addition, a significant association between increasing numbers of locusts and dry/cold conditions is found in eastern China. Plague intensity also generally increases in concert with wetness in northern China, while more precipitation is likely to have a negative effect in southern China.

The sub-fossils of leaf fragments in sediments as an indicator of mangrove development in the Yingluo Bay, Guangxi, Southwest China over the last 130 years

Located in the intertidal zone of the tropical and subtropical coasts, mangrove forests are an important ecosystem in the global carbon cycle and serve as a protector of local seashores. Under the double impacts of climate change,especially sea-level rise, and human activity, mangrove forests around the world have faced degradation, against which the reconstruction of the historical development of mangrove forests using an effective indicator has been regarded as a necessary strategy for designing a predictable model. As the primary product of mangrove forest, it is reasonable that the content of leaf fragments of mangrove(CLFM) buried in sediments in the form of sub-fossils potentially has the same indicative function for the development of mangrove forests as that of widely-used mangrove pollen. In this study, the leaf fragments of mangrove in two sediment cores(YLW02 and YLW03) drilled in the Yingluo Bay in Guangxi, Southwest China were picked out and weighted for calculation of CLFM, which was used as an indicator of mangrove development after examination of parallelism and a statistical correlation of the CLFM with the concentration of mangrove pollen. The results clearly show that the vertical distribution of the CLFM for the core taken from the landward margin of mangrove forests(YLW03) only parallels that of the local mangrove species(Rhizophora. stylosa) with a significantly positive correlation(R=0.56, P=0.05), while the vertical distribution of the CLFM for the core taken from the interface between seaward margin of mangrove forest and the trunk of tidal creeks of the bay(YLW02) parallels the summed concentration of mangrove pollen(SCMP) with a more positive correlation than that of YLW03(R=0.85, P=0.01), indicating that the trunk outlet of tidal creeks must have been the site where mangrove production gathered from the overall forest rather than from local production. The variations in the CLFM of both cores indicate that overall the mangrove forests in the Yingluo Bay have increasingly flourished over the last 130 years except for the interval of 1940–1950 AD in response to an increase in air temperature and decrease in rainfall, which would have resulted in an increase in seawater salinity;while the coupled extreme increases in air temperature and in rainfall in summer, which would have resulted in extreme decreases in seawater salinity, would be responsible for the relative degradation of mangrove forests in the interval of 1940–1950 AD.

Effect of Autumn Cutting Date on Regrowth, Turning Green, Yield and Quality of <i>Leymus chinensis</i>Grassland in Songnen Plain, Northeast China

A field study was carried out to quantify the effects of different cutting time on Leymus chinensis population and community characteristic in Songnen grassland of northeast China from August, 2006 to August, 2007. The treatment interval was ten days with the remaining stubble height of 5 cm from 15th August to 4th October in 2006. Results showed that the L. chinensis made up about 90% of the dry matter of aboveground biomass, and there were about ten species in the L. chinensis community in the 1 m × 1 m plot. The L. chinensis and Kalimeris integrifolia regrew rapidly after autumn cutting in 2016. In the second year, the coefficients of the community similarity were high between the different cutting time treatments. The density, height, aboveground biomass, stem/leaf ratio, and crude protein of L. chinensis were not significant at the turning green stage and harvesting stage, the companion species of L. chinensis community contained higher crude protein, but the crude protein of the plant community were not significant. Thus, considering the weather factor for haymaking, the harvest dates should be concentrated from the middle ten days of August to the first ten days in September.