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Improvement of cotton fibre yield and quality is challenging due to the narrow genetic base of modern cotton cultivars, which emphasizes the great need to effectively explore the existing germplasm resources. With major objective to assess the genetic diversity and population structure at DNA level, 302 elite upland cotton germplasm accessions (253 Chinese and 49 different exotic origins), were genotyped using 198 simple sequence repeats (SSRs) markers. Each of the 198 markers differed greatly in its ability to detect variations in the panel of cotton germplasm. The SSRs amplified 897 alleles, of which 77.7% were polymorphic. The number of alleles varied from 2 to 12 (mean 4.53). Gene diversity ranged from 0.020 to 0.492 with a mean of 0.279. The polymorphic information content (PIC) values ranged from 0.371 to 0.019 (mean 0.225). Genetic distances in the whole cotton germplasm ranged from 0.451 to 0.052 (mean 0.270), demonstrating relatively wider genetic diversity range. Chinese-origin cotton germplasm showed the highest level of SSR polymorphisms (gene diversity $$=$$ 0.268, PIC $$=$$ 0.218), whereas American-origin revealed the highest mean genetic distance (0.274). Model-based Bayesian analysis clustered the whole cotton germplasm into three subpopulations, and the highest molecular variation ws revealed between subpopulations (4%, $$P{

The existing methods of projection for solving convex feasibility problem may lead to slow convergence when the sequences enter some narrow“corridor” between two or more convex sets. In this paper, we apply a technique that may interrupt the monotonity of the constructed sequence to the sequential subgradient projection algorithm to construct a non-monotonous sequential subgradient projection algorithm for solving convex feasibility problem, which can leave such corridor by taking a big step at different steps during the iteration. Under some suitable conditions, the convergence is proved.We also compare the numerical performance of the proposed algorithm with that of the monotonous algorithm by numerical experiments.

To analyze the malaria situation in Shaanxi Province during 2005-2014, in the aim of providing reference for improving malaria elimination strategies and measures.Data on malaria control and malaria epidemic reports during 2005-2014 were collected, and analysis was made on prevalence and regional distribution of malaria, species of plasmodium, diagnosis of patients, and sources of imported malaria.Four hundred and fifty three cases of malaria were reported in Shaanxi Province during 2005-2014, consisting of 73 local cases （16.1%） and 380 imported cases （83.9%） of which 141 were falciparum malaria （37.1%, 141/380）. Three patients died and they all were imported cases of falciparum malaria. No indigenous infection had been reported since 2011. Most of the cases were laboratory-confirmed（71.5%, 324/453）. The falciparum malaria cases accounted for 31.1%（141/453） of all the cases, and they all were imported cases. No cases of quartan malaria and ovale malaria were reported. The 73 indigenous cases distributed in 25 districts (counties) of 7 cities, including 3 cities in South Shaanxi (Shangluo, Hanzhong, Ankang)（61.6%, 45/73） and four cities in Central Shaanxi (Xi′an, Weinan, Xianyang, Baoji) (38.4%, 28/73）. The imported cases showed an increasing trend from 24 in 2005 to 59 in 2014. The 380 imported cases were mainly from over 20 countries in Africa （72.6%, 276/380）, with top sources of Angola （64 cases）, Cameroon （26）, Ghana （24）, and Equatorial Guinea （23） accounting for 36.0% （ 137/380）. The median of interval from onset to diagnosis was 5 d. The cases were mainly reported by clinical medical institutions （87.6%, 397/453）, only 7.5% （34/453） were reported by disease control institutions.No indigenous cases have been reported since 2011, but the imported malaria cases show a trend of increase with a major source of Africa.

Association mapping is a useful tool for the detection of genes selected during plant domestication based on their linkage disequilibrium (LD). This study was carried out to estimate genetic diversity, population structure and the extent of LD to develop an association framework in order to identify genetic variations associated with drought and salt tolerance traits. 106 microsatellite marker primer pairs were used in 323 Gossypium hirsutum germplasms which were grown in the drought shed and salt pond for evaluation. Polymorphism (PIC=0.53) was found, and three groups were detected ( K =3) with the second likelihood ΔK using STRUCTURE software. LD decay rates were estimated to be 13-15 cM at r 2 ≥0.20. Significant associations between polymorphic markers and drought and salt tolerance traits were observed using the general linear model (GLM) and mixed linear model (MLM) ( P ≤0.01). The results also demonstrated that association mapping within the population structure as well as stratification existing in cotton germplasm resources could complement and enhance quantitative trait loci (QTLs) information for marker-assisted selection.

Cotton is the most important textile crop in the world due to its cellulose-enriched fibers. Sucrose synthase genes (Sus) play pivotal roles in cotton fiber and seed development. To mine and pyramid more favorable alleles for cotton molecular breeding, single nucleotide polymorphisms (SNPs) of GhSus family genes were investigated across 277 upland cotton accessions by EcoTILLING. As a result, a total of 24 SNPs in the amplified regions of eight GhSus genes were identified. These SNPs were significantly associated with at least one fiber- or seed-related trait measured in Nanjing, Anyang and Kuche in 2007–2009. Four main-effect quantitative trait nucleotides (QTNs) and five epistatic QTNs, with 0.76–3.56% of phenotypic variances explained by each QTN (PVE), were found to be associated with yield-related traits; six epistatic QTNs, with the 0.43–3.48% PVE, were found to be associated with fiber quality-related traits; and one main-effect QTN and one epistatic QTN, with the PVE of 1.96% and 2.53%, were found to be associated with seed oil content and protein content, respectively. Therefore, this study provides new information for molecular breeding in cotton.

Background: The elimination of malaria requires high-quality surveillance data to enable rapid detection and response to individual cases. Evaluation of the performance of a national malaria surveillance system could identify shortcomings which, if addressed, will improve the surveillance program for malaria elimination.Methods: Case-level data for the period 2005–2014 were extracted from the China National Notifiable Infectious Disease Reporting Information System and Malaria Enhanced Surveillance Information System. The occurrence of cases, accuracy and timeliness of case diagnosis, reporting and investigation, were assessed and compared between the malaria control stage (2005–2010) and elimination stage (2011–2014) in mainland China.Results: A total of 210 730 malaria cases were reported in mainland China in 2005–2014. The average annual incidence declined dramatically from 2.5 per 100 000 people at the control stage to 0.2 per 100 000 at the elimination stage, but the proportion of migrant cases increased from 9.8 % to 41.0 %. Since the initiation of the National Malaria Elimination Programme in 2010, the overall proportion of cases diagnosed by laboratory testing consistently improved, with the highest of 99.0 % in 2014. However, this proportion was significantly lower in non-endemic provinces (79.0 %) than that in endemic provinces (91.4 %) during 2011–2014. The median interval from illness onset to diagnosis was 3 days at the elimination stage, with one day earlier than that at the control stage. Since 2011, more than 99 % cases were reported within 1 day after being diagnosed, while the proportion of cases that were reported within one day after diagnosis was lowest in Tibet (37.5 %). The predominant source of cases reporting shifted from town-level hospitals at the control stage (67.9 % cases) to city-level hospitals and public health institutes at the eliminate stage (69.4 % cases). The proportion of investigation within 3 days after case reporting has improved, from 74.6 % in 2010 to 98.5 % in 2014.Conclusions: The individual case-based malaria surveillance system in China operated well during the malaria elimination stage. This ensured that malaria cases could be diagnosed, reported and timely investigated at local level. However, domestic migrants and overseas populations, as well as cases in the historically malarial non-endemic areas and hard-to-reach area are new challenges in the surveillance for malaria elimination.

The present study was conducted to evaluate genetic analysis of fuzzless seed trait in cotton. One hundred and two upland cotton (G. hirsutum) and eighty-five island cotton (G. barbadense) were used to cross with the same lines, TM-1 (G. hirsutum) and Xinhai 13 (G. barbadense), respectively. Two different F1 populations obtained were assessed to specify the dominant and recessive inheritance of fiber fuzziness in these lines. Three F1 populations (Kuguangzi × TM-1, Luwuxu × TM-1, and SA65 × TM-1) displaying recessive fiber fuzziness inheritance were selected to construct the F2 population for a further genetic study of fuzzless seed trait. The results of this study indicated that (1) the same materials showed different quantities of fuzzy fiber in different environments. Less fuzzy fiber was found in Xinjian and Hainan compared to Anyang. Thus, the quantity of fuzzy cotton seed depends on ecological environment. (2) In upland cotton, the inheritance of fiber fuzziness was dominant for 26 accessions (25.49%), incompletely dominant for 8 accessions (7.84%), and recessive for 22 accessions (21.57%). The inheritance of fiber fuzziness in island cotton was dominant for 5 accessions (5.88%), incompletely dominant for 16 accessions (18.82%), and recessive for 9 accessions (10.59%). Analysis of F2 population indicated that the fiber fuzziness of Kuguangzi was controlled by two recessive complementary effect alleles. The fiber fuzziness of Luwuxu was controlled by two recessive additive effect alleles, and a single recessive gene controlled the same trait for SA65. Fiber fuzziness evaluation in cotton germplasm provides the genetic and basic information for cotton fiber development study and breeding.

The impact of alien DNA fragments on plant genome has been studied in many species. However, little is known about the introgression lines of Gossypium. To study the consequences of introgression in Gossypium, we investigated 2000 genomic and 800 epigenetic sites in three typical cotton introgression lines, as well as their cultivar (Gossypium hirsutum) and wild parents (Gossypium bickii), by amplified fragment length polymorphism (AFLP) and methylation-sensitive amplified polymorphism (MSAP). The results demonstrate that an average of 0.5% of exotic DNA segments from wild cotton is transmitted into the genome of each introgression line, with the addition of other forms of genetic variation. In total, an average of 0.7% of genetic variation sites is identified in introgression lines. Simultaneously, the overall cytosine methylation level in each introgression line is very close to that of the upland cotton parent (an average of 22.6%). Further dividing patterns reveal that both hypomethylation and hypermethylation occurred in introgression lines in comparison with the upland cotton parent. Sequencing of nine methylation polymorphism fragments showed that most (7 of 9) of the methylation alternations occurred in the noncoding sequences. The molecular evidence of introgression from wild cotton into introgression lines in our study is identified by AFLP. Moreover, the causes of petal variation in introgression lines are discussed.

With 1 figure and 8 tables Abstract The genetic effects and heterosis of the colour and quality of brown fibres were analysed in this paper through the complete 5 × 5 diallel crossing among two brown cotton cultivars and three white cotton cultivars in upland cotton (Gossypium hirsutum). Parents and F1 were arranged in a randomized block design in three locations. The results showed that the inheritability for all the traits has exceeded 50%, with significant dominance effect at the 0.01 level. The additive effect of fibre colour, lint percentage, elongation and strength was also significant at the 0.01 level, reaching 85.6%, 29.7%, 16.1% and 19.1%, respectively. The ratio of residual variance of lint percentage and fibre qualities was 29.5 – 45.9%, that of colour was only 1.1%. Fibre colour had significant negative correlation with lint percentage, fibre length, uniformity, elongation and strength. The mid-parent heterosis of fibre colour was negative, which was −0.7%; those of lint percentage, fibre length, uniformity and strength were 3.5%, 4.2%, 1.7% and 2.6%, respectively, reaching the significant level. The simple correlation coefficient between heterosis of fibre length and strength and SSR genetic distance was 0.718 and 0.724, respectively, with a significant level. For the heterosis utilizing, the fibre quality of F1 could be predicted via the mean value of the fibre qualities of parents or the SSR genetic difference among varieties (lines). Selection among the early hybrid generations was suggested. Regional planning could be applied to improve lint percentage and fibre qualities by taking advantage of environmental variation.

With 2 figures and 4 tables Abstract A novel super-dwarf mutant, named AS98, was discovered from an interspecific hybrid in 1998. Compared to the normal line LHF10W99, plant height and internode length were significantly shorter in AS98, but it had only slightly (3–5%) fewer internodes. Therefore, the shorter plant height was the result of shorter internodal length. AS98 was crossed with LHF10W99, and the F1, F2, BC1, and BC2 populations were used for genetic analysis of the dwarf trait. The results showed that the trait was controlled by a single incomplete-dominant gene. Exogenous application of gibberellin acid (GA3), brassinosteroid and indol acetic acid showed a significant response to GA3, which could restore plant height in AS98. The results thus provide a basis for utilizing the dwarf trait in breeding and studying the biosynthesis of GA or signal transduction in cotton.

Through analyzing the national statutory reporting data on typhoid, paratyphoid fever in 2012, we were trying to understand the whole picture of typhoid, paratyphoid fever at the national level as well as to understand the trends and characteristics of typhoid and paratyphoid fever in provinces with high incidence rate, so as to the development of prevention and control strategies of the diseases in those high-incidence rate provinces.We descriptively analyzed the national typhoid and paratyphoid fever statutory reporting data which was reported through disease surveillance information reporting system in 2012.11 998 cases with typhoid and paratyphoid fever were reported with 3 fatal ones, in 2012 in the whole country. The incidence rate was 0.89 per 100 000. Compared to the data gathered in 2011, the incidence rates of typhoid/ paratyphoid fever increased by 1.20%. The total number of the confirmed cases on typhoid and paratyphoid fever was 6522 and was accounted for 54.36% of the total cases, in which paratyphoid fever accounted for 36.86%. Cases were mainly involved farmers and followed by students and children. Incidence rates of typhoid and paratyphoid fever in children aged 0-4 years old appeared the highest (respectively 1.31/100 000 and 0.46/100 000). Yunnan,Guizhou,Guangdong,Guangxi, Zhejiang, Hunan and Xinjiang provinces (autonomous regions)were identified as provinces with high-incidence rates of typhoid and paratyphoid fever. During 2005-2012, the incidence rates in most of the above high-incidence provinces showed a downward trend, except for in Guangdong which had only showed a slight change. There were variations on peak period and highly-hit population in seven high-incidence provinces.The incidence rate of typhoid/paratyphoid fever was in a relatively low level in China. Prevention and control strategies on the diseases in children under 5 years old remained a challenge, warranted more work to be done. The epidemiological situation is still severe in some high-incidence rate provinces.

To understand the incidence rates of both typhoid fever and paratyphoid fever in the high prevalent areas of Guizhou province so as to provide evidence for the development of programs on comprehensive intervention and effectiveness evaluation.Six townships in Pingba county were selected as intervention areas while six townships in Kaiyang county were taken as control. All hospitals and clinics were classified into A, B and C types according to its level and the capacity of the blood culture. Surveillance on typhoid and paratyphoid fever was conducted based on all population and all hospitals, clinics and county CDCs among the patients with unknown fever.In the surveillance area in those two counties, there were 12 944 blood samples from patients with unknown fever which have been tested and cultured. Among them, 200 strains of Salmonella including 16 typhoid strains, 184 paratyphoid A strains were identified, with the total positive rate as 1.55%. The positive rate before the intervention program was higher than the after. The detection rate was 1.91% in the type A hospitals. 39 strains of Salmonella have been cultured from 2039 samples which accounting for 19.50% (39/200) of the total strains. 4315 blood samples were cultured at the 'Class B' sites which isolated 82 strains of Salmonella, accounting for 41.00% (82/200), with a detection rate as 1.90%. 6590 samples were cultured at the 'Class C' sites, which identified 79 strains of Salmonella, accounting for 39.50% (79/200), with a detection rate as 1.20%. The detection rate was much higher before the use of antibiotics than after using them (P0.05). The annual peak time of positive detection was in spring and fall. The outbreaks or epidemics often appeared in the same places, with farmers, students as the high-risk populations. Symptoms of both typhoid and paratyphoid fever were not typical.Typhoid and paratyphoid monitoring programs which covered primary health care institutions in the high incidence area seemed to be effective in reflecting the pictures as well as the burden of both typhoid and paratyphoid.

To evaluate the burden of paratyphoid fever A in Hongta district, Yuxi city, Yunnan province from May 1, 2008 to April 30, 2009 so as to provide information for the development of comprehensive intervention measures.Based on the Fever Syndromic Surveillance System, information as attendance rate of patients with fever, rate of patients being sampled, laboratory testing rate, sensitivity on the detection of blood culture and the rate of case reporting etc. were calculated. According to the pyramid model of food-borne disease on disease burden, the local actual incidence of paratyphoid fever A was estimated and analyzed.Under the Fever Syndromic Surveillance System, there were 6642 fever cases being detected, among whom 6570 cases were sampled and undergone testing, with the sampling rate as 98.92% and all the samples received laboratory testing. There were 354 positive cases of paratyphoid fever A reported, all from the Hongta district. Data showed that the attendance rate of the feverish patients was 73.53%, with the highest rate seen in whose under 10 years old (100%). Assumed that the sensitivity of paratyphoid fever blood culture was 70%, and the case reporting rate was 90%, we estimated that the annual incidence of paratyphoid fever A in Hongta was 220.33 (95%CI: 170.1 - 521.4) per 100 thousand, with 965 (95%CI: 745 - 2284) as new cases. Among all the age groups, the incidence in the age group from 15 to 44 years old was estimated to be at the highest (318.27 per 100 thousand).Hongta seemed to be an endemic region for paratyphoid fever A, with the highest incidence occurred in the age group of between 15 and 44 years old. These findings highlighted the urgent need to carry out further investigation on the risk factors and to implement targeted effective prevention and control measures.

To clarify the seasonal and geographical difference and pathogen patterns so as to provide reference of prevention and control of the disease through analyzing the epidemic characteristics of reported hand-foot-mouth disease (HFMD) cases in China, 2008 - 2009.We analysed the epidemiological data of HFMD from the Chinese national notifiable infectious diseases reporting system in 2008 and 2009.There were 488 955 and 1 155 525 reported HFMD cases in 2008 and 2009, in China, of which 1165 and 13 810 were severe and 126 and 353 were fatal, respectively. The notification rates were 50.09/10 million, 68.47/10 million and 59.04/10 million in high, medium and low latitudes areas, respectively. The epidemic periods in Medium and Low latitude were from 12 to 24 weeks in 2009, and in high latitude it was from 23 to 35 weeks. HFMD cases were concentrated mainly in 5 year-old or even younger children, accounted for 92.23% of the total cases. The incidence rate of two years old appeared to be the highest. The features of severe and death case concentrated in lower age groups were more evident, and the proportion of severe case and case fatality rate under 1 years old was higher than that in other age groups. We also noticed that with the increasing of age, the proportion of severe case and case fatality rate had a decreasing trend. There was a difference between the pathogens seen. The relative risk (RR) for an human enterovirus 71 (HEV71) isolate was higher among severe case than in common cases (RR = 1.82), whereas the RR for an EV71 isolate was higher among the death cases than in common cases (RR = 2.11). There was seasonal variation of pathogen composition. There were 477 clusters of cases from 2008 to 2009, of which 389 found in preschools, 47 in rural villages, outbreaks of clusters were mainly from April to July.The HFMD epidemics was increasing in 2009. The epidemic of HFMD in different latitudes area and seasons was different. Children of five year old or under were the major population groups at risk, of HFMD. The younger ones had higher risk of becoming severe and death cases. HEV71 and coxsackievirus A16 were both the major etiologic agents of HFMD. The preschool and rural villages were the main settings of clusters of cases.

That is a good way that use the ARCH family models to describe the time-varying characteristic of the return sequence on stocks. Intuitively, the influence to present from the long history data should not bigger than the short history data. So the order restriction to the parameter is according to the fact better. This paper researched the maximum likelihood estimator (MLE) of the parameters in the β - ARCH(0,q) model under the nonnegative restriction. At last we use the model in Chinese stock market.

To characterize the spatial distribution of typhoid and paratyphoid fever (TPF) in Yunnan province, China and to determine the effectiveness of meteorological factors on the epidemics of TPF.Data of reported TPF cases in Yunnan province (2001 - 2007) from the China Information System for Diseases Control and Prevention was applied to GIS-based spatial analyses to detect their spatial distribution and clustering of TPF incidence at the county level. Panel data analysis was used to identify the relationships between the TPF incidence and meteorological factors including monthly average temperature, monthly cumulative precipitation and monthly average relative humidity.During the study period, the average incidence of TPF in Yunnan province was 23.11/100 000, with majority of the TPF cases emerged in summer and autumn. Although widely distributed, two TPF clusters were detected in Yunnan province based on the spatial analysis: one area around Yuxi city with the average annual incidence as 207.45/100 000 and another at the junctions of Yunnan province with Burma and Laos. Based on results from panel data analysis, the incidence of TFP was shown to be associated with meteorological factors such as temperature, precipitation, relative humidity and one month lag of temperature increase [10°C increase in the monthly average temperature: IRR = 1.30 (95%CI: 1.24 - 1.36); 10% increase in monthly average relative humidity: IRR = 1.07 (95%CI: 1.05 - 1.09); 100 mm rise in monthly cumulative precipitation: IRR = 1.02 (95%CI: 1.00 - 1.03); and 10°C average temperature increase, the last month: IRR = 1.73 (95%CI: 1.64 - 1.82)].Areas with high TPF incidence were detected in this study, which indicated the key areas for TPF control in Yunnan province. Meteorological factors such as temperature, precipitation and humidity played a role in the incidence of TPF.

To acknowledge the epidemiology of gastroenteritis outbreaks caused by noroviruses and their genotypes.Epidemiologic data and specimens were collected from 19 gastroenteritis outbreaks. 201 specimens were detected for norovirus, rotavirus, astrovirus, adenovirus and sapovirus by RT-PCR methods and PCR products were sequenced. Sequence alignment and phylogenetic analysis were performed by Clustal X 1.83 and MEGA 4.0 programs.Noroviruses were one of the most predominant pathogens causing viral gastroenteritis outbreaks (12 of 19 outbreaks, accounting for 63.2%). Variant GII-4/2006b was the predominant strain responsible for 11 of the 12 NV-associated outbreaks. Other genotypes would include GII-17, GII-6 and GII-3. The NV-associated gastroenteritis outbreaks occurred mainly in winter and spring between December 2006 and April 2007. These gastroenteritis outbreaks caused by noroviruses would involve all age groups in various locations. Meantime, 2 out of 12 outbreaks were caused by norovirus or other viruses. In addition, multiple viruses and multiple genotypes of noroviruses were found in the same outbreak.Noroviruses were one of the most major pathogens causing gastroenteritis outbreaks while GII-4/2006b variant was identified as the predominant strain in China.

By analyzing the group variations of Chinese school-aged youth, to gather scientific bases for establishing a screening norm for obesity.More than 228,250 students aged 6 through 18 years participated in the 2000 National Surveillance on Students Health and Physical Fitness were enrolled as subjects, and were divided into various groups. The P(5), P(50) and P(95) of BMI were calculated and compared.The differences of BMI among various groups were mainly reflected in the P95 high level of BMI, e.g., the means of BMI of boys aged 13 in large cities and in relatively underdeveloped rural areas were 25.7 and 21.1 with a difference of 4.6, and 22.8 and 20.3 for girls aged 11 with a difference of 2.5. Evident north-south differences were also found, especially during adolescent growth spurt. The means of BMI of those lived in the north and south China were 22.3 and 21.0 for girls aged 11 (difference 1.3), and 25.4 and 23.5 for boys aged 14 (difference 1.9), respectively. These findings clearly showed that much more obese youth exist in the metropolis than in the rural areas, and in the north than in the south China. The difference in BMI between the developed areas and developing areas could be found in early school ages. They were 22.5 and 16.7 for boys aged 7, and 19.8 and 16.7 for girls aged 7, respectively, which is a dominant difference among Chinese youth groups. However, that the BMI differences in the P(5) level were not as evident as in the high level means that malnutrition and under-weight were still popular in all Chinese youth groups.In making a national norm for screening obesity in China, we'd better take high-level growth population as reference, to adapt the secular growth changes of Chinese youth. However, the huge urban-rural, north-south, developed-developing differences shown in this study should also be taken into full consideration, in order to make the screen norm be accepted by most of the Chinese youth groups.

In order to develop strategies on prevention and cure for obesity, a study regarding dynamic analyses on the prevalence of obesity and overweight of Chinese children and adolescents was carried out.Data of more than 980 thousands students of Han nationality, aged 7 through 18 years old were collected from National Surveys on Chinese Students' Constitution and Health which were carried out in 1985, 1991, 1995 and 2000. Samples were divided into four groups as "metropolis", "medium and small sized cities", "prosperous village" and "below-averaged village". Study targets were screened using the new criterion-the "Reference Norm for Screening Overweight and Obesity in Chinese Children and Adolescents" which was set up by the Working Group on Obesity in China. The prevalence of overweight and obesity in various groups in different years were compared and analyzed.The prevalence rates of obesity in 1985 including from the metropolis area, were only 0.2% and 0.1% for boys and girls, and the prevalence of overweight was between 1% and 2% indicating that was no trend of obesity epidemic then. However, a rapid increase of overweight prevalence has been noticed since the early 1990s, and the increments were more seen in the urban than in the rural areas and more in boys than in girls. In the most developed cities including Beijing, the prevalence rates of obesity appeared to be 4.7%, 3.8% and 3.2%, among three groups with higher risk: the 7 - 9, 10 - 12 year-old boys and 7 - 9 year-old girls, respectively. Both high prevalence rates of malnutrition and overweight were also found in that period. Around 1995, a large scale of increments of overweight were found both in the urban and rural groups. In the most developed metropolis, the prevalence of overweight was two to three folds more than that of 10 years ago. The prevalence of obesity were 6% - 8% for boys and 4% - 6% for girls, respectively. Since 2000, most of the Chinese metropolis have started the so called 'overall increment period' of obesity. The prevalence rates of obesity plus overweight had reached 25.4%, 25.5%, 17.0% and 14.3% for boys aged 7 - 9 years and 10 - 12 years, and girls aged 7 - 9 years and 10 - 12 years, respectively. Among them, the prevalence rates of obesity were 12.9% and 9.1% for boys aged 7 - 9 and 10 - 12 years, which had already reached the average level seen in the medium-developed countries in the world. Although the increments of overweight were high, the prevalence of obesity was still low in most of the other groups: 4.8% for boys and 2.6% for girls in the "medium sized" group, 1.5% for boys and 1.7% for girls in the "prosperous village" group, and 0.9% for boys and 1.2% for girls in the "below-averaged village" group, respectively.The prevalence of obesity in Chinese children and adolescents was considered to be still relatively low. However, the rapid increasing of both obesity and overweight, in both urban and rural areas would arouse special attention. Comprehensive strategies of intervention should include periodical monitoring, education on pattern of nutrition, oxygen-consuming physical exercises and healthy dietary behavior. Two areas on obesity prevention to protect the child from becoming overweight in early ages, and to control the tendency of obesity from overweight, should be emphasized in order to improve the health status and life quality of the Chinese children and adolescents.

To analyze the epidemiological status of overweight and obesity in various student groups and the prevalence changes in recent 15 years, in order to take effective preventive measures against obesity.Students aged 7 through 22 years participated in the 1985 and 2000 National Surveys on Students Constitution and Health were used as subjects. The newly established BMI screening criteria for overweight and obesity, to analyze the prevalence among various populations.In 2000, the prevalence rates of obesity were 4.37%,1.46%,2.32% and 0.92% and that of overweight were 10.38%,4.34%,5.94% and 3.67% for the urban boys, rural boys urban girls and rural girls, respectively, which were all significantly increased in multiple times as compared with those in 1985. However, significant differences could be found among various areas. The prevalence rates of obesity in several metropolitans have reached 9.63% for males and 4.50% for females, and those of overweight have reached 15.29% for males and 8.77% for females, respectively. Most of the other areas are still staying at the early prevalence stage. The prevalence of obesity in the Western China is generally low, and actually no prevalence of obesity is found in the rural female population.It's an urgent task to act on a series of comprehensive measures to prevent and cure the obesity of youth in China's developed areas from now on. However, corresponding effective measures of obesity prevention are also needed in other areas of this country.