期刊文献+
共找到2,195篇文章
< 1 2 110 >
每页显示 20 50 100
Forest characteristics,population structure and growth trends of threatened relict Pseudotsuga forrestii in China 被引量:1
1
作者 Cindy Q.Tang Shi-Qian Yao +8 位作者 Peng-Bin Han Jian-Ran Wen Shuaifeng Li Ming-Chun Peng Chong-Yun Wang Tetsuya Matsui Yong-Ping Li Shan Lu Yuan He 《Plant Diversity》 SCIE CAS CSCD 2023年第4期422-433,共12页
Pseudotsuga forrestii is a relict evergreen coniferous tree species in Pinaceae endemic to China.P.forrestii tree numbers have greatly decreased due to deforestation,over-utilization and habitat degradation.Here we cl... Pseudotsuga forrestii is a relict evergreen coniferous tree species in Pinaceae endemic to China.P.forrestii tree numbers have greatly decreased due to deforestation,over-utilization and habitat degradation.Here we clarify P.forrestii community types,structure,species diversity,seedling recruitments and growth trends.We identified four P.forrestii community types:(1)Pseudotsuga forrestii-Quercus guyavifolia-Acer davidii evergreen coniferous and broad-leaved mixed forest;(2)Pseudotsuga forrestii-Pinus yunnanensis-Quercus guyavifolia evergreen coniferous and broad-leaved mixed forest;(3)Pseudotsuga forrestii evergreen coniferous forest;(4)Pseudotsuga forrestii-Abies georgei var.smithii evergreen coniferous forest.P.forrestii forests are characterized by both warm temperate and temperate affinities.Simpson diversity,Pielou evenness,Shannon-Wiener diversity indices ranged from 0.75 to 0.76,0.74-0.81,and 1.62-1.93,respectively,with no significant differences among the four forest types.The forest stratification was multilayered.The canopy layer was generally 10-25 m tall,with the emergent layer reached 25-42 m.DBH and age structures of P.forrestii showed multimodal distributions.Its maximum age P.forrestii was 570 years with a DBH of 143 cm.The growth of annual ring width of P.forrestii was slow,and generally decreased with age,whereas the basal area at the breast height increased with age.Established seedlings/saplings were mainly found in unstable micro-habitats.Regeneration of P.forrestii depends on moderate natural disturbances.Finally,we provide recommendations for P.forrestii conservation. 展开更多
关键词 Pseudotsuga forrestii Community structure Species diversity population structure Regeneration Growth trend
下载PDF
Physical activity, physical fitness, and body mass index in the Chinese child and adolescent populations: An update from the 2016 Physical Activity and Fitness in China The Youth Study 被引量:33
2
作者 Peijie Chen 《Journal of Sport and Health Science》 SCIE 2017年第4期381-383,共3页
In this special issue of the Journal of Sport and Health Science,analyses of the most recent national prevalence estimates from the 2016 Physical Activity and Fitness in China—The Youth Study(PAFCTYS)are presented.Th... In this special issue of the Journal of Sport and Health Science,analyses of the most recent national prevalence estimates from the 2016 Physical Activity and Fitness in China—The Youth Study(PAFCTYS)are presented.These include the prevalence of moderate-to-vigorous physical activity(MVPA)。 展开更多
关键词 ACTIVITY An update from the 2016 Physical Activity and Fitness in China Physical activity The Youth Study and body mass index in the Chinese child and adolescent populations physical fitness
下载PDF
Population trends, threats, and conservation recommendations for waterbirds in China 被引量:14
3
作者 Xiaodan Wang Fenliang Kuang +1 位作者 Kun Tan Zhijun Ma 《Avian Research》 CSCD 2018年第2期89-101,共13页
Background: China is one of the countries with abundant waterbird diversity. Over the past decades, China's waterbirds have suffered increasing threats from direct and indirect human activities. It is important to... Background: China is one of the countries with abundant waterbird diversity. Over the past decades, China's waterbirds have suffered increasing threats from direct and indirect human activities. It is important to clarify the population trends of and threats to waterbirds as well as to put forward conservation recommendations.Methods: We collected data of population trends of a total of 260 waterbird species in China from Wetlands International database. We calculated the number of species with increasing, declining, stable, and unknown trends. We collected threatened levels of waterbirds from the Red List of China's Vertebrates(2016), which was compiled according to the IUCN criteria of threatened species. Based on literature review, we refined the major threats to the threatened waterbird species in China.Results: Of the total 260 waterbird species in China, 84 species(32.3%) exhibited declining, 35 species(13.5%) kept stable, and 16 species(6.2%) showed increasing trends. Population trends were unknown for 125 species(48.1%). There was no significant difference in population trends between the migratory(32.4% decline) and resident(31.8% decline) species or among waterbirds distributed exclusively along coasts(28.6% decline), inland(36.6% decline), and both coasts and inland(32.5% decline). A total of 38 species(15.1% of the total) were listed as threatened species and 27 species(10.8% of the total) Near Threatened species. Habitat loss was the major threat to waterbirds, with 32 of the total 38(84.2%) threatened species being affected. In addition, 73.7%(28 species), 71.1%(27 species), and 57.9%(22 species) of the threatened species were affected by human disturbance, environmental pollution, and illegal hunting, respectively.Conclusions: We propose recommendations for waterbird conservation, including(1) strengthening conservation of nature wetlands and restoration of degraded wetlands,(2) enhancing public awareness on waterbird conservation,(3) improving the enforcement of Wildlife Protection Law and cracking down on illegal hunting,(4) carrying out longterm waterbird surveys to clarify population dynamics,(5) restoring populations of highly-threatened species through artificial intervention, and(6) promoting international and regional exchanges and cooperation to share information in waterbirds and their conservation. 展开更多
关键词 水鸟 多样性 中国 动物学
下载PDF
Long-term trends in the abundance and breeding performance in Adélie penguins:the Argentine Ecosystem Monitoring Program
4
作者 Mariana A.JUÁRES AnahíM.SILVESTRO +1 位作者 Brenda C.ALFONSO M.Mercedes SANTOS 《Advances in Polar Science》 CSCD 2024年第1期132-140,共9页
In this work,we report long-term trends in the abundance and breeding performance of Adélie penguins(Pygoscelis adeliae)nesting in three Antarctic colonies(i.e.,at Martin Point,South Orkneys Islands;Stranger Poin... In this work,we report long-term trends in the abundance and breeding performance of Adélie penguins(Pygoscelis adeliae)nesting in three Antarctic colonies(i.e.,at Martin Point,South Orkneys Islands;Stranger Point/Cabo Funes,South Shetland Islands;and Esperanza/Hope Bay in the Antarctic Peninsula)from 1995/96 to 2022/23.Using yearly count data of breeding groups selected,we observed a decline in the number of breeding pairs and chicks in crèche at all colonies studied.However,the magnitude of change was higher at Stranger Point than that in the remaining colonies.Moreover,the index of breeding success,which was calculated as the ratio of chicks in crèche to breeding pairs,exhibited no apparent trend throughout the study period.However,it displayed greater variability at Martin Point compared to the other two colonies under investigation.Although the number of chicks in crèche of Adélie penguins showed a declining pattern,the average breeding performance was similar to that reported in gentoo penguin colonies,specifically,those undergoing a population increase(even in sympatric colonies facing similar local conditions).Consequently,it is plausible to assume a reduction of the over-winter survival as a likely cause of the declining trend observed,at least in the Stranger Point and Esperanza colonies.However,we cannot rule out local effects during the breeding season affecting the Adélie population of Martin Point. 展开更多
关键词 long-term monitoring Adélie penguin breeding pairs chicks crèched breeding success population trends
下载PDF
Lion Hunting and Trophy Quality Records in Zambia for the Period 1967-2000: Will the Trends in Trophy Size Drop as Lion Population Declines?
5
作者 Chansa Chomba Ramadhani Senzota +1 位作者 Harry Chabwela Vincent Nyirenda 《Open Journal of Ecology》 2014年第4期182-195,共14页
Data on lion skull measurements taken were collected and analyzed to determine trends in trophy size as an indicator of population size, and area of origin among the concessioned hunting areas in Zambia for the period... Data on lion skull measurements taken were collected and analyzed to determine trends in trophy size as an indicator of population size, and area of origin among the concessioned hunting areas in Zambia for the period 1967-2000. A comparison of trophy quality was also made with Tanzania and Zimbabwe which were the other two key sources of lion trophies in Africa. It was assumed that a comprehensive analysis of lion trophy sizes obtained from trophy hunting would be used as an indicator of hunting pressure on lion populations in Zambia. This approach was used because trophy size is an index of abundance particularly for species such as lion which are difficult to count using conventional census methods. Record lion trophies from Safari Club International rating were also collected and assessed to compare trophy quality obtained from Zambia and those of Tanzania and Zimbabwe for the same period 1967-2000 (33 years). Results obtained suggested that Zambia’s contribution to the record trophies under Safari Club International did not decline in the intervening period 1967-2000 and could not be used as an effective indicator of lion population in Zambia. At regional level, Zambia had second highest 24%, after Tanzania 56%, while Zimbabwe was third, 20%. It was found that the size of skulls could not be used as an effective indicator of population size as the record trophies did not decline while the population was alleged to have declined on the continent. Other factors, such as genetic, low prey densities, snaring, poisoning and problem animal control needed to be investigated to determine their impact on the lion population status. 展开更多
关键词 LION Trophy Measurement trend DECLINE population SIZE
下载PDF
Is hepatic steatosis associated with left ventricular mass index increase in the general population?
6
作者 Katharina Piontek Carsten O Schmidt +5 位作者 Sebastian E Baumeister Markus M Lerch Julia Mayerle Marcus Dorr Stephan B Felix Henry Volzke 《World Journal of Hepatology》 CAS 2017年第19期857-866,共10页
AIM To investigate the association between hepatic steatosis and change in left ventricular mass index(LVMI) over five years, and examine whether systolic and diastolic blood pressures are mediators of the association... AIM To investigate the association between hepatic steatosis and change in left ventricular mass index(LVMI) over five years, and examine whether systolic and diastolic blood pressures are mediators of the association between hepatic steatosis and LVMI using a general population sample.METHODS We analyzed data from the Study of Health in Pomerania. The study population comprised 1298individuals aged 45 to 81 years. Hepatic steatosis was defined as the presence of a hyperechogenic pattern of the liver together with elevated serum alanine transferase levels. Left ventricular mass was determined echocardiographically and indexed to height2.7. Path analyses were conducted to differentiate direct and indirect paths from hepatic steatosis to LVMI encompassing systolic and diastolic blood pressure as potential mediating variables.RESULTS Hepatic steatosis was a significant predictor for all measured echocardiographic characteristics at baseline. Path analyses revealed that the association of hepatic steatosis with LVMI change after five years was negligibly small(β =-0.12, s.e. = 0.21, P = 0.55). Systolic blood pressure at baseline was inversely associated with LVMI change(β =-0.09, s.e. = 0.03, P < 0.01), while no association between diastolic blood pressure at baseline and LVMI change was evident(β = 0.03, s.e. = 0.05, P = 0.56). The effect of the indirect path from hepatic steatosis to LVMI via systolic baseline blood pressure was small(β =-0.20, s.e. = 0.10, P = 0.07). No indirect effect was observed for the path via diastolic baseline blood pressure(β = 0.03, s.e. = 0.06, P = 0.60). Similar associations were observed in the subgroup of individuals not receiving beta-blockers, calcium channel blockers, or drugs acting on the reninangiotensin system.CONCLUSION Baseline associations between hepatic steatosis and LVMI do not extend to associations with LVMI change after five years. More studies are needed to study the longitudinal effects of hepatic steatosis on LVMI. 展开更多
关键词 Hepatic steatosis Left ventricular mass index Blood pressure General population Study of Health in Pomerania
下载PDF
Population dynamics and condition index of natural stock of blood cockle,Tegillarca granosa(Mollusca,Bivalvia,Arcidae)in the Marudu Bay,Malaysia
7
作者 Joanna W.Doinsing Vienna Anastasia Admodisastro +1 位作者 Laditah Duisan Julian Ransangan 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2021年第8期89-97,共9页
The population parameters of blood cockles,Tegillarca granosa in the intertidal zone of Marudu Bay,Sabah,Malaysia were investigated based on monthly length-weight frequency data(July 2017 to June 2018).A total of 279 ... The population parameters of blood cockles,Tegillarca granosa in the intertidal zone of Marudu Bay,Sabah,Malaysia were investigated based on monthly length-weight frequency data(July 2017 to June 2018).A total of 279 cockle individuals with shell length and weight ranging from 27.7 mm to 82.2 mm and 13.11 g to 192.7 g were subjected to analysis.T.granosa in Marudu Bay showed a consistent moderately high condition index 4.98±0.86 throughout the year.The exponent b of the length-weight relationship was 2.6 demonstrating negative allometric growth.The estimated asymptotic length(L_(∞)),growth coefficient(K)and growth performance(Ф)of the T.granosa population in Marudu Bay were estimated at 86.68 mm,0.98 a^(-1) and 3.87,respectively.The observed maximum shell length was 82.55 mm and the predicted maximum shell length was 84.44 mm with estimated maximum life span(t_(max))of 3.06 years.The estimated mean lengths at the end of 2,4,6,8,10 and 12 months of age were 21.31 mm,31.16 mm,39.53 mm,46.63 mm,52.67 mm and 57.79 mm.Total,natural,and fishing mortalities were estimated at 2.39 a^(-1),1.32 a^(-1) and 1.07 a^(-1).The exploitation level(E)was 0.45.Results of the current study also demonstrated that T.granosa in the Marudu Bay has two major recruitment peaks;one in March and another in October.The exploitation level revealed that natural stock of T.granosa in the Marudu Bay was approaching the maximum exploitation level.If such trend continues or demand for T.granosa is increasing,coupled with no effective fisheries management in place,possibility of the T.granosa population in the Marudu Bay to collapse is likely to elevate. 展开更多
关键词 Arcidae population dynamics condition index Marudu Bay
下载PDF
Self-similarity of spanwise rotational motions’population trends in decelerating open-channel flow
8
作者 Peng Zhang Yanchong Duan +4 位作者 Qiang Zhong Danxun Li Shengfa Yang Jiang Hu Wenjie Li 《Theoretical & Applied Mechanics Letters》 CAS CSCD 2022年第3期213-219,共7页
Decelerating open-channel flow is a type of flow that gradually moves forward with decreasing velocity and increasing water depth.Although all flow parameters change along the streamwise direction,previous studies hav... Decelerating open-channel flow is a type of flow that gradually moves forward with decreasing velocity and increasing water depth.Although all flow parameters change along the streamwise direction,previous studies have revealed that these parameters’vertical distributions at different sections can be universally described with a single profile when being nondimensionalised by appropriate scales.This study focuses on the population trends of spanwise rotational motions at various sections along the main flow direction by particle imaging velocimetry(PIV)measurement.The wall-normal population distributions of density,radius,swirling strength,and convection velocity of the prograde and retrograde motions show similar trends in uniform open-channel flows.The dimensionless representation is invariant along the main flow direction.This study’s results indicate the self-similar characteristic of population trends of spanwise rotational motions prevails in decelerating open-channel flow. 展开更多
关键词 SELF-SIMILARITY population trends Spanwise rotational motions Decelerating open-channel flow Equilibrium flow
下载PDF
Characteristics of Dry and Wet Climate in Shandong Province Based on Standardized Precipitation Index
9
作者 Ningxin ZHANG Fengling ZENG Fang LI 《Meteorological and Environmental Research》 2024年第3期6-15,共10页
Based on the monthly precipitation data of 116 meteorological stations in Shandong Province during 1970-2021,standardized precipitation index(SPI)was calculated,and the methods of linear fitting,mutation test and Morl... Based on the monthly precipitation data of 116 meteorological stations in Shandong Province during 1970-2021,standardized precipitation index(SPI)was calculated,and the methods of linear fitting,mutation test and Morlet wavelet analysis were used to analyze the change trend and temporal and spatial distribution characteristics of SPI index in the past 52 years.The results show that there were more normal years in Shandong Province,and the frequency reached 38.46%.There was severe drought in the 1980s and more wet years after 2003.SPI index showed an upward trend in spring,summer and winter but a weak arid trend in autumn.In addition,intense dry weather was more frequent in summer.Spatially,the climate was normal or humid in most areas of Shandong Province.The regions with more wet years were located in the central and northeast Shandong and the peninsula,while the climate was normal in the southwest and north of Shandong.The areas with more dry years were mainly located in the northwest of Shandong Province.There was mainly local and global drought in Shandong Province,and the arid area showed a decreasing trend.In the past 52 years,Shandong Province experienced quasi-4 times of alternation between dry and wet climate.The long period of 21 a was the first main period,and the climate would be still wet in Shandong Province in the future.In terms of mutation,the climate in Shandong Province became humid after 2003,and 2003 was the mutation point.After the abrupt change,the climate changed from gradually drying to wetting. 展开更多
关键词 Standardized precipitation index Shandong Province Dry and wet climate characteristics trend analysis
下载PDF
Population Status and Trend of Water Dependent Grazers (Buffalo and Waterbuck) in the Kenya-Tanzania Borderland
10
作者 Moses Makonjio Okello Lekishon Kenana +12 位作者 Hanori Maliti John Warui Kiringe Erastus Kanga Fiesta Warinwa Samwel Bakari Nathan Gichohi Stephen Ndambuki Hamza Kija Noah Sitati David Kimutai Machoke Mwita Daniel Muteti Philip Muruthi 《Natural Resources》 2015年第2期91-114,共24页
Even though over many years the IUCN has considered the African buffalo and waterbuck and abundant species in Africa with no conservation concern, the situation is rapidly changing. Using aerial counts in wet and dry ... Even though over many years the IUCN has considered the African buffalo and waterbuck and abundant species in Africa with no conservation concern, the situation is rapidly changing. Using aerial counts in wet and dry season in 2010 and 2013, this study assessed the trend, population status and distribution of the African buffalo and common waterbuck in the Northern Tanzania and Southern Kenya borderland. Both species were rare in the borderland, with the Amboseli region had the highest number of buffalo (241.5 ± 29.9), followed by Magadi/Namanga (58.0 ± 22.0), West Kilimanjaro (38.8 ± 34.9), and lastly Lake Natron (14.5 ± 9.0) areas. In terms of density, Amboseli also led with 0.03 ± 0.00 (buffalo per km2), but rest had similar densities of 0.01 ± 0.00 buffalo per km2. In terms of percent changes in buffalo, Amboseli area had a positive increase (+10.59 ± 27.71), but with a negative growth of -17.12 in the dry season. All other changes in all locations had negative (decline) buffalo numbers over time. For waterbuck numbers, Amboseli area also led with 12.3 ± 3.9 waterbuck), followed by Magadi/Namanga (10.3 ± 3.7.0), Lake Natron (3.8 ± 3.4), and lastly West Kilimanjaro (0.5 ± 0.5) areas. In terms of waterbuck density, they were low and less than 0.00 ± 0.00 per km2. For percent changes in waterbuck numbers, Magadi/Namanga had higher positive change (+458.33 ± 291.67), but all other locations had negative (decline) changes with the worst being West Kilimanjaro and Lake Natron areas. Further, buffalo number was dependent (p = 0.008) on the season, with numbers being higher in the wet season than dry season. For waterbuck, numbers were independent (p = 0.72) of the season, with numbers being similar across seasons. The findings of this study showed that both species were negatively affected by drought. We recommend a constant joint monitoring program between Kenya and Tanzania, and jointly combat poaching, habitat fragmentation and encroachment to build viable populations in the borderland. 展开更多
关键词 AFRICAN BUFFALO Common Waterbuck BORDERLAND Kenya population trend and Status Tanzania
下载PDF
Trends of Population Growth in China:Maximum Number Will Exceed 1.5 Billion
11
《China Population Today》 1996年第1期16-17,共2页
TrendsofPopulationGrowthinChina:MaximumNumberWillExceed1.5BillionⅠ.TheTrendofChina'sPopulationGrowthataLowFe... TrendsofPopulationGrowthinChina:MaximumNumberWillExceed1.5BillionⅠ.TheTrendofChina'sPopulationGrowthataLowFertilityRateThemos... 展开更多
关键词 trends of population Growth in China
下载PDF
Population Status and Trend of the Maasai Ostrich in the Mid Kenya—Tanzania Borderland
12
作者 Moses Makonjio Okello John Warui Kiringe +12 位作者 Lekishon Kenana Fiesta Warinwa Hanori Maliti Noah Wasilwa Sitati Erastus Kanga Samwel Bakari Stephen Ndambuki Philip Muruthi Nathan Gichohi Edeus Massawe David Kimutai Machoke Mwita Daniel Muteti 《Natural Resources》 2016年第10期558-579,共22页
The Maasai ostrich (Struthio camelus) is a the largest avian species in East Africa and though it’s not considered to be a species of conservation concern, some populations are on the decline and this is attributed t... The Maasai ostrich (Struthio camelus) is a the largest avian species in East Africa and though it’s not considered to be a species of conservation concern, some populations are on the decline and this is attributed to bush meat activities, predation on their eggs illegal consumption by humans, habitat destruction and forage competition with other large wildlife species. Climate change is also emerging to be another major threat due to interference with food availability which in turn interferes with the breeding rhythm. Thus, this study examined the population status, trend and distribution of the Maasai ostrich in the Southern Kenya and Northern Tanzania borderland after the 2007 to 2009 drought. The results showed that the species was found across the entire borderland but the Amboseli region had the highest number and density of Maasai ostrich (726.00 ± 100.9;0.08 ± 0.01 ostriches per km<sup>2</sup>), followed by Lake Natron area (330.8 ± 69.8;0.05 ± 0.01 ostriches per km<sup>2</sup>) and the least was in West Kilimanjaro (85.5 ± 18.0;0.03 ± 0.01 ostriches per km<sup>2</sup>). Drought caused a decline in the population of the Maasai ostrich but the Amboseli area experienced the highest decline in density (?13.44 ± 12.61) compared to other borderland sectors. However, the populations increased in most sectors after the drought, and wet season numbers and densities were higher than the dry season. The highest positive increase in number and density was in Lake Natron area (+85.65 ± 91.06) followed by West Kilimanjaro (+68.39 ± 59.54), and the least was in the Magadi area (+22.26 ± 32.05). There is a need to enhance conservation of avian species like the Maasai ostrich other than just focusing on the charismatic species such as the African elephant and black rhino. We therefore recommend joint collaboration in monitoring all large wildlife populations across the Kenya-Tanzania borderland with a view of understanding their status, trend and best management actions that can enhance their conservation. 展开更多
关键词 BORDERLAND Kenya Maasai Ostrich population trend and Status Tanzania
下载PDF
Post Drought Population Status and Trend of Specialized Browsers in the Mid Kenya-Tanzania Borderland
13
作者 Moses Makonjio Okello John Warui Kiringe +12 位作者 Philip Muruthi Lekishon Kenana Hanori Maliti Noah Wasilwa Sitati Erastus Kanga Fiesta Warinwa Samwel Bakari Stephen Ndambuki Nathan Gichohi Edeus Massawe David Kimutai Machoke Mwita Daniel Muteti 《Natural Resources》 2016年第10期580-610,共31页
We examined the population status, trend and distribution of Gerenuk, Fringe-eared Oryx and Lesser kudu in the Northern Tanzania and Southern Kenya borderland after the 2007 to 2009 drought. The species were character... We examined the population status, trend and distribution of Gerenuk, Fringe-eared Oryx and Lesser kudu in the Northern Tanzania and Southern Kenya borderland after the 2007 to 2009 drought. The species were characterized by low numbers and sparsely distributed in the borderland but were more prevalent and abundant in the Amboseli region. However, West Kilimanjaro had the highest positive change in density between 2010 and 2013 [Gerenuk = +1650.48 ± 1150.31, lesser kudu = +912.78 ± 487.63 and Fringe-eared Oryx = +366.65 ± 233.32]. Changes in density and composition varied seasonally among the different sectors of the borderland, with Gerenuk having the highest change in the Amboseli area during the wet season. Lesser kudu had the highest change in Amboseli and Kilimanjaro during the wet season while Fringe-eared Oryx had the highest change in the wet season in West Kilimanjaro area. Spatial distribution of the species varied seasonally and across different sectors of the borderland. In the dry season, Gerenuk exhibited a clumped distribution mainly in Amboseli National Park, and between Natron and West Kilimanjaro but in the wet season, it spread out more though higher concentrations were still found Amboseli and West Kilimanjaro. Lesser concentrated in mostly in West Kilimanjaro and Amboseli during the dry season but was widely dispersed during the wet season. Similarly, during the dry season, the Fringe-eared Oryx was confined in the Amboseli and West Kilimanjaro areas but during the wet season, it much more spread out with clusters in the Mbirikani area of the Amboseli region and a few places in Magadi, Natron and West Kilimanjaro. Management implications of the findings obtained in this study area here-in discussed. 展开更多
关键词 BORDERLAND Fringe-Eared Oryx Gerenuk Kenya Lesser Kudu population trend and Status Tanzania
下载PDF
Sex modification of the association of the radial augmentation index and incident hypertension in a Chinese community-based population
14
作者 Qiao QIN Fang-Fang FAN +11 位作者 Meng-Yuan LIU Bo LIU Jia JIA Long ZHANG Yu-Xi LI Yi-Meng JIANG Peng-Fei SUN Dan-Mei HE Jian-Ping LI Ming CHEN Bo ZHENG Yan ZHANG 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2021年第1期39-46,共8页
BACKGROUND Arterial stiffness,as assessed by aortic ultrasound and pulse wave velocity,is associated with incident hypertension.However,there is still no consensus on whether the augmentation index(AI)affects new onse... BACKGROUND Arterial stiffness,as assessed by aortic ultrasound and pulse wave velocity,is associated with incident hypertension.However,there is still no consensus on whether the augmentation index(AI)affects new onset of hypertension.This study investigated the relationship of radial AI(r AI)and incident hypertension in a Chinese community-based population without hypertension at baseline.METHOD A total of 1,615 Chinese non-hypertensive participants from an atherosclerosis cohort in Beijing,China were included in our analysis.Baseline r AI normalized to heart rate of 75 beats/min(r AIp75)was obtained using HEM-9000 AI.New-onset hypertension was defined as blood pressure≥140/90 mm Hg or self-reported hypertension or taking anti-hypertensive medications at the follow up survey.Multivariate regression models were used to evaluate the impact of r AIp75 on the risk of new-onset hypertension.RESULTS After a mean 2.35-year follow-up,213(13.19%)participants developed incident hypertension.No significant relation between r AIp75 and incident hypertension was observed in the whole population after adjustment for possible confounders(adjusted odds ratio(OR)and 95%confidence interval(CI):1.09[0.95-1.27];P=0.2260).However,r AIp75 was significantly associated with incident hypertension in women,but not in men(adjusted OR and 95%CI:1.29[1.06-1.56],P=0.0113 for women;0.91[0.72-1.15],P=0.4244 for men;P for interaction=0.0133).CONCLUSIONS Sex modified the effect of the r AI on incident hypertension in a Chinese,community-based,non-hypertensive population.Screening of the r AI could be considered in women with a high risk of hypertension for the purpose of primary intervention. 展开更多
关键词 Sex modification of the association of the radial augmentation index and incident hypertension in a Chinese community-based population
下载PDF
Variations and trends of the freezing and thaw- ing index along the Qinghai-Xizang Railway for 1966-2004 被引量:8
15
作者 JIANG Fengqing HU Ruji LI Zhen 《Journal of Geographical Sciences》 SCIE CSCD 2008年第1期3-16,共14页
Annual freezing and thawing index of 7 meteorological stations along the Qing- hai-Xizang Railway were calculated based on daily maximum and minimum temperature records for 1966-2004. Trends of annual freezing and tha... Annual freezing and thawing index of 7 meteorological stations along the Qing- hai-Xizang Railway were calculated based on daily maximum and minimum temperature records for 1966-2004. Trends of annual freezing and thawing index were analyzed using the Mann-Kendall test and a simple linear regression method. The results show that: 1) The mean annual freezing indices range from 95 to 2300℃·d and the mean annual thawing indices range from 630 to 3250℃·d. The mean annual freezing index of the 7 stations exhibited decreasing trends with decreasing rate of -16.6- -59.1 ℃·d/10a. The mean annual thawing index of these 7 stations showed increasing trends with the related decreasing rate is 19.83-45.6℃·d/10a. 2) The MK trend test indicated the significant decreasing trends (significant at 〈 0.05 significant level) in the annual freezing index for most stations except for Golmud. The significant increasing trends can be observed in the annual thawing index for 4 stations except Golmud and Tuotuohe. Golmud was the only station with no trends in both annual freezing and annual thawing index. 展开更多
关键词 freezing and thawing index global warming trends Qinghai-Xizang Railway
下载PDF
Characteristics and dynamics analysis of Populus euphratica populations in the middle reaches of Tarim River 被引量:11
16
作者 Wu, JunXia Zhang, XiMing +2 位作者 Deng, ChaoZhou Liu, GuoJun Li, Hong 《Journal of Arid Land》 SCIE 2010年第4期250-256,共7页
关键词 populus euphratica population static life table survivorship curve survival analysis development index time sequence
下载PDF
The Control Efficiency of Plant Alcohol Extracts on the Laboratory Populations of Myzus persicae(Sulzer)and Lipaphis erysimi (Kaltenbach) 被引量:8
17
作者 ZHOU Qiong, LIANG Guang-wen ,ZENG Ling and SHEN Shu-ping(Department of Biology, Xiangtan Normal University, Xiangtan 411201 , P. R. China Laboratory of Insect Ecology , South China Arigcultural University ,Guangzhou 510642 , P. R. China) 《Agricultural Sciences in China》 CAS CSCD 2002年第11期1199-1203,共5页
The effects of semiochemicals extracted from 63 species of plants, on peach aphid (Myzus per-sicae) and mustard aphid (Lipaphis erysimi), were studied in laboratory. The deterrent rate, reproduction deterrent index an... The effects of semiochemicals extracted from 63 species of plants, on peach aphid (Myzus per-sicae) and mustard aphid (Lipaphis erysimi), were studied in laboratory. The deterrent rate, reproduction deterrent index and the interferential index of population control (IIPC) was used to evaluate the efficiency of semiochemicals on population control of the two target aphids. The results showed that the extracts of 34 species of common plants have noticeable effect on both aphid populations, especially, Xanthium sibiricum Petr. Et Widd. and Syngonium podophyllum Schott. These plant extracts could be used to construct the plant pro-tectant to protect crops. 展开更多
关键词 Plant alcohol extracts Peach aphid [Myzus persicae(Sulzer)] Mustard aphid [Lipaphis erysimi (Kaltenbach)] Deterrent rate Interferential index of population control (IIPC)
下载PDF
Climate Change and Livelihood Vulnerability of the Local Population on Sagar Island, India 被引量:2
18
作者 MUKHERJEE Nabanita SIDDIQUE Giyasuddin +2 位作者 BASAK Aritra ROY Arindam MANDAL Mehedi Hasan 《Chinese Geographical Science》 SCIE CSCD 2019年第3期417-436,共20页
This paper attempts to assess the vulnerability to climate change of human communities in selected mouzas of Sagar Island,South 24 Parganas District of India. A primary household survey has been conducted to collect d... This paper attempts to assess the vulnerability to climate change of human communities in selected mouzas of Sagar Island,South 24 Parganas District of India. A primary household survey has been conducted to collect data on socio-demographic profile, livelihood strategy, health, food, water, social network, natural disaster and climate variation indicators, were selected for Livelihood Vulnerability Index(LVI) and Livelihood Vulnerability Index-Intergovernmental Panel on Climate Change(LVI-IPCC) analyses to measure and compare the vulnerability of mouzas(administrative unit) currently suffering from frequent flooding, coastal erosion and embankment breaching on an annual basis. Secondary data collected from the Indian Meteorological Department, the Water Resources Information System of India and the Global Sea Level Observing System have been used to identify dynamics of climate change by employing statistical and Geographic Information System(GIS) techniques. A GPS survey has been conducted to identify locations of embankment breaching, and satellite images obtained from the National Aeronautics and Space Administration and U.S. Geological Survey(NASA USGS) Government website have been applied to shoreline and land use change detection, using a supervised maximum likelihood classification. The results indicate that the study area has experienced increasing temperature, changing precipitation patterns, rise in sea level, higher storm surges, shoreline change, constant land loss, embankment breaching and changing land use, which have had impact on vulnerability, particularly of poorer people. The LVI(0.48 to 0.68) and LVI-IPCC(0.04 to 0.14) scores suggest that the populations of Dhablat, Bankimnagar, Sumatinagar, Muri Ganga and Sibpur mouzas are highly vulnerable(LVI scores of 0.60 to 0.68 and LVI-IPCC scores of 0.11 to 0.14) to climate change both because the communities are more exposed to it, and because poor access to food, health facilities and water makes them extremely sensitive to it and lowers their adaptive capacity. The findings of this study could be crucial to framing further development and adaptation strategies relating to climate change, and to safeguarding the estuarine ecosystem and the vulnerable population. 展开更多
关键词 climate change LIVELIHOOD VULNERABILITY index(LVI) adaptation strategies ESTUARINE ECOSYSTEM VULNERABLE population
下载PDF
POPULATION DISTRIBUTION AND ITS CHANGE IN GUANGZHOU CITY 被引量:1
19
作者 周春山 许学强 司徒诗敏 《Chinese Geographical Science》 SCIE CSCD 1998年第3期2-12,共0页
I.POPULATIONDISTRIBUTIONCHARACTERISTICSBytheendof1994,thepopulationofGuangzhouCityhadincreasedto3.803milion,... I.POPULATIONDISTRIBUTIONCHARACTERISTICSBytheendof1994,thepopulationofGuangzhouCityhadincreasedto3.803milion,apopulationsizera... 展开更多
关键词 population DISTRIBUTION population DISTRIBUTION characteristics CHANGE trend
下载PDF
Space-time analysis of the changing patterns of population pressure on the ecological environment in China 被引量:1
20
作者 Dongqi Sun Jinliang Jiang +2 位作者 Jianbin Xu Liang Zhou Yi Hu 《Chinese Journal of Population,Resources and Environment》 2015年第4期341-348,共8页
This paper examines the temporal change and spatial variation of population pressure on the ecological environment in China.We have collected sufficient data from the statistical yearbooks of 31 provincial administrat... This paper examines the temporal change and spatial variation of population pressure on the ecological environment in China.We have collected sufficient data from the statistical yearbooks of 31 provincial administrative areas in 1990,1995,2000,2005,and 2010.Using a geographic information system(GIS) and relevant models,we analyzed the trend of the population pressure on ecological environment and the change of the gravity center of ecological environment quality.We conclude that:(1) generally,population pressure on the ecological environment in China was becoming higher during1990-2010,especially in some areas where the population and environment were in serious imbalance and the ecological environment experienced severe pollution;(2) during a certain period,population pressure on the ecological environment was becoming lower in some areas,but the ecological environment was getting worse;(3) the areas with super-high population pressure on the ecological environment were Beijing,Tianjin,and Shanghai;(4) the gravity center of population pressure on the ecological environment and the center of ecological environment quality move differently during the study time period,but the general trend was similar- both of them were moving from west to east.Based on the analysis,this paper also provides some policy suggestions on the control of ecological environment quality. 展开更多
关键词 Chinese population ECO-ENVIRONMENT ECO-ENVIRONMENTAL pressure CHANGING trend SPACE-TIME analysis
下载PDF
上一页 1 2 110 下一页 到第
使用帮助 返回顶部