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.

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.

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.

Bowel preparation protocol for hospitalized patients ages 50 years or older:A randomized controlled trial

BACKGROUND The incidence and mortality rate of colorectal cancer progressively increase with age and become particularly prominent after the age of 50 years.Therefore,the population that is≥50 years in age requires long-term and regular colonoscopies.Uncomfortable bowel preparation is the main reason preventing patients from undergoing regular colonoscopies.The standard bowel preparation regimen of 4-L polyethylene glycol(PEG)is effective but poorly tolerated.AIM To investigate an effective and comfortable bowel preparation regimen for hospitalized patients≥50 years in age.METHODS Patients were randomly assigned to group 1(2-L PEG+30-mL lactulose+a lowresidue diet)or group 2(4-L PEG).Adequate bowel preparation was defined as a Boston bowel preparation scale(BBPS)score of≥6,with a score of≥2 for each segment.Non-inferiority was prespecified with a margin of 10%.Additionally,the degree of comfort was assessed based on the comfort questionnaire.RESULTS The proportion of patients with a BBPS score of≥6 in group 1 was not significantly different from that in group 2,as demonstrated by intention-to-treat(91.2%vs 91.0%,P=0.953)and per-protocol(91.8%vs 91.0%,P=0.802)analyses.Furthermore,in patients≥75 years in age,the proportion of BBPS scores of≥6 in group 1 was not significantly different from that in group 2(90.9%vs 97.0%,P=0.716).Group 1 had higher comfort scores(8.85±1.162 vs 7.59±1.735,P<0.001),longer sleep duration(6.86±1.204 h vs 5.80±1.730 h,P<0.001),and fewer awakenings(1.42±1.183 vs 2.04±1.835,P=0.026)than group 2.CONCLUSION For hospitalized patients≥50 years in age,the bowel preparation regimen comprising 2-L PEG+30-mL lactulose+a low-residue diet produced a cleanse that was as effective as the 4-L PEG regimen and even provided better comfort.

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.

Effects of Different Planting Years on Physicochemical Properties and Enzyme Activities in Soil of Rice-Cherry Tomato Rotation

Crop rotation periodicity has always been one of the research focuses currently. In this study, the physicochemical properties, nutrient contents and enzyme activities were investigated in soils from rice-cherry tomato rotation for one year (1a), three years (3a), five years (5a), seven years (7a) and ten years (10a), respectively. The major objective was to analyze the optimal rotation years of rice-cherry tomato from soil perspective, so as to provide theoretical basis for effectively avoiding continuous cropping obstacles of cherry tomato via studying the response characteristics of soil physicochemical properties, nutrient contents and enzyme activities to planting years of rice-cherry tomato rotation system. The results were as follows: 1) Soil pH value was increased year by year during 1a to 5a, reached the highest value 5.32 at 5a. However, soil acidity was sharply enhanced during 7a to 10a (P P •kg-1 at 5a. 3) The content of soil available phosphorus was increased year by year with increasing of crop rotation years, and increased by 110% to 173% during 3a to 10a (P P P < 0.05). In conclusion, long-term single rotation pattern of rice-cherry tomato would aggravate soil acidification, prompt soil nutrient imbalance and reduce soil enzyme activity. 5a to 7a would be the appropriate rotation period for rice-cherry tomato, or else it would reduce soil quality, resulting in a new continuous cropping obstacle of cherry tomato.

Improving the Use of Insecticide-Treated Nets among Children under Five Years Old in Benin, West Africa

Background: In Benin, malaria represents the first cause of consultation and hospitalization (48% for children under 5 years old) in health units. It also accounts for 23.1% of deaths recorded in health facilities (MoH, 2019). Between the two main components of vector control adopted by Benin government, the mass distribution campaigns of Insecticide-Treated Nets (ITNs) remained the only proven cost-effective way to rapidly achieve high and equitable coverage (WHO, 2017). After the fourth mass distribution campaign conducted in 2017, the Demographic and Health Survey (DHS) data indicated that the percentage of children who slept under an ITN has increased from 20% in 2006 to 70% in 2011-2012 and to 76% in 2017-2018 while the incidence of malaria (tested positive) is increasing rapidly among children under 5 years old, growing from 36.5% in 2009 to 28.8% in 2012 and then to 51.4% in 2019. This study aims to understand this contrast by identifying the origin of the increase in ITN use over time among children under five years old and the factors which determine this use. Methods: Data from the Demographic and Health Survey (DHS) conducted in Benin respectively in 2006 and in 20018 were used during the analysis, which covered 13,445 children under five years old from 2006 DHS and 12,255 children from 2017-2018 DHS. Firstly, the data were analyzed using decomposition method to highlight the origin of the increase of ITN use over time among children under five years old. Secondly, the chi-square test analysis estimated the association between ITN use and some characteristics (wealth index, maternal or caregiver education level and child age). Finally, the logistic regression model was used to identify the main factors, which influence the net use over the study period. Results: This study shows that the improvement of basic conditions is the main origin of behavior change in the use of ITNs among children under five years old. This improvement of the basic conditions consists of making ITNs available in households and informing household members about the benefits of ITN use. So, the free ITN distribution campaigns, routine distribution, awareness campaigns about the benefits of ITN use are the strategies, which increase the household capacities and knowledge, allowing household members to make their children sleep under net. The analysis also shows that region of residence, wealth index of household, household size, religion, and child age continue to determine the ITN use among children under age 5 years old and MNCP will integrate the factors in malaria prevention strategies in order to achieve universal use of ITNs. Conclusions: Although, sleeping under ITN behavior has indeed spread among children under 5 years old, policymakers and other stakeholders should design strategies to maintain and improve the current level of ITN use to reach the collective protection threshold (80% according to WHO). Therefore, to address the challenges of universal use of ITN, the study recommends expanding the routine distribution system to private sector health centers;discussing issues related to health service utilization (particularly ITN use) within a consultation framework at the communal level. In addition, collecting qualitative and quantitative data in the Oueme region will allow better understanding of all aspects of the ITN use gap among children under 5 years.

The Prevalence and Risk Factors Associated with Otitis Media in Children under Five Years of Age in Mogadishu, Somalia: A Hospital-Based Cross-Sectional Study

Background: Otitis media (OM) is highly prevalent and is one of the most important causes of preventable hearing loss in developing countries and it may have long-term impacts on the children. Several hospital-based cross-sectional studies have been conducted in East African countries to assess the prevalence of OM;however, no similar studies have been conducted in Somalia. Therefore, we conducted a hospital-based cross-sectional study to identify the prevalence and the underlying risk factors of OM among children under the age of five in Mogadishu, Somalia. Methodology: A hospital-based cross-sectional study was conducted from July 2022 to November 2022 at three main hospitals in Mogadishu, Somalia. A total of 384 children aged less than 5 years were included. Parents of these children were interviewed with a questionnaire and a clinical examination was performed for each child. The Statistical Package for Social Sciences, SPSS (Version 22, IBM, Inc.), was used for the statistical analysis. Result: The prevalence of otitis media among the 384 children recruited was 31.25% (120/384). Otitis media was significantly associated with age less than one year (P = 0.006), malnutrition (P Conclusion: In summary, the present study found that otitis media was highly prevalent (31.25%) in Mogadishu, Somalia. The majority of the affected children were younger than one year. Age of the child, malnutrition, upper respiratory tract infections, feeding in lying position, and dripping something into a child’s ear were found to significantly increase the risk of developing otitis media in children. In contrast, breastfeeding for more than one year has been found to reduce the risk of developing otitis media in children.

Mental Health Consequences among Sudanese Due to the Armed Conflicts and Civil Unrest of 2023: One Year Later

Aim: To investigate depression, anxiety, PTSD, and insomnia levels among Sudanese citizens after a year has passed since the start of Armed Forces conflict in Sudan. Methods: An online survey was distributed. It is composed of five parts, covering the following areas: 1) sociodemographic data;2) depression assessment;3) generalized anxiety disorder assessment;4) post-traumatic stress disorder assessment;and 5) insomnia assessment. Statistical Package for Social Sciences version 27 was used for data analysis;frequency and percentage were used to describe the qualitative variables. Spearman’s correlation analysis and Chi-square test were used for correlation and association analysis;a P-value equal to or less than 0.05 was considered statistically significant. Results: The study included 283 participants, primarily female (76.0%), with a mean age of 35.26 ± 6.96 years. The majority of participants were married (50.5%) and had a university level of education (50.2%). At the start of the war, 70.3% of participants were inside the war zones, and at the time of data collection, 73.5% were outside Sudan. The length of stay in the war zone ranged from 1 to 300 days, with a mean of 48.59 ± 70.284 days. Additionally, 63.3% of participants stated that they did not receive any form of mental health intervention, and the remaining did not provide an answer. There was a high prevalence of moderate-severe depression (50.5%), moderate anxiety (35.3%), PTSD (56.5%), and sub-threshold insomnia (53.4%) among the participants. Correlation analyses revealed associations between demographic factors such as sex, age, marital status, and education and mental health issues. Notably, female participants showed a higher prevalence of PTSD (53.0%) compared to male participants (67.6%). Conclusions: There is a substantial impact of war-related trauma on mental health, revealing a high prevalence of moderate-severe depression, moderate anxiety, PTSD, and sub-threshold insomnia among the participants. This emphasizes the importance of tailored interventions and support systems to address the unique needs of individuals affected by war trauma.

PACT/WAR工艺在腈纶污水处理工程中的应用

丙烯腈/腈纶污水污染物浓度高,含难生化处理的低聚物,处理难度大,成为困扰企业污水达标排放的难题。介绍了国内企业腈纶污水处理的工程实践及实验研究,采用PACT/WAR工艺处理腈纶污水的工程实例。工程运行表明:该工艺处理包括丙烯腈/腈纶污水在内的炼油、化工污水,处理效果良好,能够达到一级直排标准。针对运行中出现的问题,提出相应的解决方案及优化建议。

LESSONS FROM THE 50 POSTWAR YEARS

Fifty years is but a twinkle of the eye in the long stream ofhuman history,but each 50 year period is one of the links in thechain that connects the past to the present,and each link has itown significance.At the turn of the century it is fit for us to re-view cool-headly the changes in world politics in the last 50 yearsso as to be able to explore on the world of the 21st century.

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.

Remote forcing of Indian Ocean warming on Northwest Pacific during El Nio decaying years:a FOAM model approach

This paper attempts to analyze in detail the remote influence of the Indian Ocean Basin warming on the Northwest Pacific(NWP) during the year of decaying El Ni o.Observation data and the Fast Ocean- Atmosphere coupled Model 1.5 were used to investigate the triggering conditions under which the remote influence is formed between the positive sea surface temperature(SST) anomaly in the North Indian Ocean and the Anomalous Northwest Pacific anticyclone(ANWPA).Our research show that it is only when there is a contributory background wind field over the Indian Ocean,i.e.,when the Indian Summer Monsoon(ISM) reaches its peak,that the warmer SST anomaly in the North Indian Ocean incites significant easterly wind anomalies in the lower atmosphere of the Indo-West tropical Pacific.This then produces the remote influence on the ANWPA.Therefore,the SST anomaly in the North Indian Ocean might interfere with the prediction of the East Asia Summer Monsoon in the year of decaying El Ni o.Both the sustaining effect of local negative SST anomalies in the NWP,and the remote effect of positive SST anomalies in the North Indian Ocean on the ANWPA,should be considered in further research.

Wells评分、Geneva评分和YEARS法对疑似肺栓塞住院患者诊断价值的对比研究

目的探讨Wells评分、Geneva评分和YEARS法对疑似肺栓塞(PE)住院患者的诊断价值。方法回顾性分析2017年1月至2020年6月因胸痛、呼吸困难和咯血于湖南省人民医院住院治疗的946例疑似PE患者。记录所有入组患者病史、临床表现和辅助检查结果等指标。入组患者均接受Wells评分、Geneva评分和YEARS法评估。以CT肺血管造影(CTPA)为标准,分析3种评分诊断PE的灵敏度、特异度、准确度和Youden指数,同时将3组评分结果与CTPA结果进行一致性分析,并绘制受试者工作特征曲线(ROC),计算曲线下面积(AUC),评估3种评分系统诊断PE价值。结果 946例患者中CTPA确诊为PE患者257例(27.2%)。Wells评分、 Geneva评分、YEARS法诊断PE灵敏度分别为88.72%、75.88%、93.00%,特异度分别为35.37%、59.36%、25.11%,准确度分别为50.11%、63.85%、43.55%,Youden指数分别为0.24、0.35、0.18。Wells评分、Geneva评分、YEARS法与CTPA的Kappa值分别为0.16、0.28、0.11。3种评分准确度两两比较差异均有显著统计学意义(P<0.01)。Wells评分、Geneva评分、YEARS法诊断PE的AUC分别为0.622±0.019、0.676±0.019、0.591±0.020,其中Geneva评分AUC最大,与Wells评分、YEARS法差异均有统计学意义(P<0.0167),Wells评分与YEARS法差异无统计学意义(P>0.0167)。结论 3种评分对疑似PE住院患者均有一定的诊断价值,Geneva评分整体诊断价值最高,Wells评分和YEARS法诊断均不理想。

Wells评分和YEARS法对肺栓塞诊断价值的比较

目的:探讨深静脉血栓可能性评分(Wells评分)和简便诊断处理可疑肺栓塞(YEARS法)对肺栓塞患者的诊断价值,应用受试者工作特征(ROC)曲线对比Wells评分和YEARS法诊断肺栓塞的曲线下面积(AUC),以期发现更适用于临床的肺栓塞评分方法。方法:选取因疑似肺栓塞的住院患者139例,其中临床确诊肺栓塞患者48例,收集所有入选患者的病史、临床表现和辅助检查等结果,所有入选研究对象均进行Wells评分和YEARS法评估,将肺动脉血管造影(CTPA)作为诊断的金标准,应用SPSS 22.0统计软件分析2组患者Wells评分和YEARS法诊断肺栓塞的灵敏度、特异度、误诊率、漏诊率和准确度,并对Wells评分、YEARS法和CTPA的结果进行一致性分析,进一步绘制Wells评分和YEARS算法诊断肺栓塞的ROC曲线,计算并比较AUC。结果:与YEARS法比较,Wells评分对肺栓塞诊断的特异度和准确度明显升高(P<0.05),误诊率明显降低(P=0.037),而灵敏度和漏诊率差异无统计学意义(P>0.05)。Wells评分与CTPA的Kappa值为0.45,一致性强度为中度;YEARS法与CTPA的Kappa值为0.22,一致性强度尚可;Wells评分与YEARS法的Kappa值为0.11,一致性较差。Wells评分方法诊断肺栓塞的AUC为0.753±0.044 (P<0.01),YEARS法诊断肺栓塞的AUC为0.585±0.049 (P=0.101)。结论:Wells评分在肺栓塞诊断评估方面总体上优于YEARS法。

可疑肺栓塞诊断新策略--YEARS评分

肺栓塞是一种误诊率、漏诊率极高的常见肺血管病,早期识别、早期诊治对改善患者预后至关重要。肺动脉造影是确诊肺栓塞的“金标准”,因其昂贵、有创、有辐射暴露风险,在临床已经逐渐被CT肺血管造影取代。但可疑肺栓塞的患者如果未经有效评估,可能导致过度检查及不必要的医疗资源浪费,也增加了患者辐射暴露的风险。为了有效筛查可疑肺栓塞,目前有多种评分模型对可疑肺栓塞进行评估,但传统评分法相对较复杂,不易在临床工作广泛推广使用。YEARS评分是近年来针对可疑肺栓塞进行评估的新型评分模型,其是一种简单、快速的评估肺栓塞可能性的工具,可以安全有效排除可疑肺栓塞患者,该评分标准更为简便,易于记忆和临床推广。但因目前其临床应用研究有限,有待进一步在临床验证该评分的诊断价值。本文就YEARS评分的临床研究做一综述,以期为肺栓塞的诊断提供新思路、新方法。

Forest change of China in recent 300 years

Based on historical documents, modern survey and statistics, as well as the result of predecessor studies, the trend and main process of forest dynamics are recognized. The forest area and forest coverage rates for each province of China from 1700 to 1949 are estimated backward by every 50 years. Linking the result with modern National Forest Inventory data, the spatial-temporal dynamics of Chinese forest in recent 300 years （AD 1700-1998） is quantitatively analyzed. The study shows that in recent 300 years, the forest area in current territory of China has declined by 0.95×10^8 hm^2 （or 9.2% of the coverage rate） in total, with a trend of decrease and recovery. Before the 1960s, there was a trend of accelerated descending. The forest area was reduced by 1.66×10^8 hm^2 （or 17% of the coverage rate） in 260 years. While after the 1960s, there has been a rapid increase. The forest area increased by 0.7×10^8 hm^2 （or 8% of the coverage rate） in 40 years. The study also shows that there is a significant spatial difference in the dynamics of forest. The amplitudes of increasing and decreasing in western China are both smaller than the ones in eastern China. During the rapid declining period from 1700 to 1949, the most serious decrease appeared in the Northeast, the Southwest and the Southeast, where the coverage rate in most provinces dropped over 20%. In Heilongjiang Province, the coverage rate dropped by 50%. In Jilin Province, it dropped by 36%. In Sichuan Province and Chongqing Municipality, it dropped by 42%. In Yunnan Province, it dropped by 35%. During the recovery period 1949-1998, the western provinces, municipality and autonomous regions, including Ningxia, Gansu, Inner Mongolia, Sichuan-Chongqing, Yunnan, Tibet, Xinjiang and Qinghai, etc, the increase rates are all below 5%, while the eastern provinces, municipality and autonomous regions （except Heilongjiang, Hubei, Jiangsu-Shanghai） have achieved an increase over 5%, among which the Guangdong-Hainan, Guangxi, Anhui, Beijing-Tianjin-Hebei, Shandong, Henan, Zhejiang, and Fujian have an increase over 10%.

The ostracod assemblages and their environmental significance in the Chen Co area, southern Tibet in recent 1400 years

The CC1 core, with a length of 216 cm, was drilled in the west part of the Chen Co (Lake) in southern Tibet Plateau. The210Pb and137Cs measurement indicated that it was a consecutive sedimentary sequence since ca. 1400 years. The ostracoda and their assemblages under the level of 1 cm samples’ cutting interval were finished for this core to reveal the past environmental changes in the lake area. A total of 15 species of ostracods belonging to 7 genera in the core sediments had been identified. According to the ostracod distributions, abundances and preservations in the core, seven ostracod assemblages had been distinguished. The ostracod assemblages and their ecological features, together with the sediments dating decision were used to infer the past ca. 1400 years environmental changes of the Chen Co environmental evolutions in three stages, which had responded to the Medieval Ages Warm-period (MAW), the Little Ice Age (LIA) and modern warm period. The results show that the changes of the Chen Co environment had been mainly influenced by the climatic variations. The trend of the lake level fluctuations had been accorded with that of climatic variation during the past 1400 years.

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.