Background:Human cystic echinococcosis(CE)and alveolar echinococcosis(AE)are highly endemic in Tibetan communities of Sichuan Province.Previous research in the region indicated that domestic dog was the major source o...Background:Human cystic echinococcosis(CE)and alveolar echinococcosis(AE)are highly endemic in Tibetan communities of Sichuan Province.Previous research in the region indicated that domestic dog was the major source of human infection,and observations indicated that domestic dog could have more access to intermediate hosts of Echinococcus spp.:both domestic livestock(CE)viscera and small mammals(AE),in early winter and again in spring.We hypothesized that there would therefore be a significant increase in the risk of canine infection with Echinococcus spp.in these two seasons and conducted a reinfection study to investigate this further.Methods:Faecal samples were collected from owned dogs in seven townships in Ganze Tibetan Autonomous Prefecture(Sichuan Province,China),and Echinococcus spp.infection status was determined using copro-antigen ELISA.Dogs were sampled in April(spring),July(early summer),September/October(autumn/early winter)and December(winter)in 2009;and in April(spring)2010.Dogs were treated with praziquantel following each of the five sample collections to eliminate any tapeworms.Information on dog sex,age and body weight was also collected.The t-test,Fisher’s exact test,Poisson regression and logistic regression were used to compare means and prevalences,and to identify factors associated with infection status.Results:The proportion of female dogs was significantly lower than that of male dogs;female dogs had significantly higher(22.78%)baseline copro-ELISA prevalence than males(11.88%).Dog body weight,sex,age,county and previous infection status at any sampling point had no influence on the re-infection prevalence in general.Poisson regression did not found a significant influence on the re-infection prevalence due to different deworming/sampling time spans.Dogs exhibited significantly higher re-infection prevalences in spring and early summer of 2009 and in early winter between September/October and December of 2009,suggesting a higher infection pressure in these seasons comparing with other seasons.Conclusion:Following praziquantel treatment,dog body weight,sex,age,county,deworming time span and previous infection status at any sampling point had no influence on the re-infection prevalence in the region in general.The differences between re-infection prevalences were probably due to the seasonality in Echinoccocus spp.infection pressure in the region.Early winter,spring and early summer should be important seasons for optimal dog deworming intervention in these Tibetan communities.展开更多
The purpose of this paper is to provide understanding of the seasonal pattern of air leakage(infiltration)in Chinese vernacular buildings across China’s five climate regions.In achieving the set purpose,a grand exten...The purpose of this paper is to provide understanding of the seasonal pattern of air leakage(infiltration)in Chinese vernacular buildings across China’s five climate regions.In achieving the set purpose,a grand extensive literature survey was conducted and supported with data drawn from established Meteonorm V6.1 on sensible heat and psychrometric variables.Numerical computations for normalized and specific infiltration from stack effects followed the Gowri method in line with ASHRAE reference 2004.Solar energy admittance into building followed Bouger’s model form Angstrom properties.From the distribution of vernacular buildings across five climate regions of China,evidence from computational and numerical values showed symmetries in terms of minimums and maximums times of occurrence.Further,a reciprocal pattern exists between solar radiative admittance and region’s temperature profile.Knowing that Chinese vernacular building heritage extended to further Asia,this research became limited to only the Chinese region.It became difficult to report if the construction culture away from China has correlation with infiltration and energy admittance value.Earlier works on Chinese climate and vernacular dwellings reported a climate responsive dwelling designed by passive cooling strategy;a gap was closed by extending the previous work to specific infiltration pattern and energy admittance level.Chinese vernacular buildings by virtue of research outcomes are and should be adoptable to modern housing needs for cultural integration.展开更多
Nitrogen deposition has a considerable impact on biogeochemical cycling in terrestrial ecosystems.However,how litter production and element return respond to N addition remains poorly understood in nitrogen-rich subtr...Nitrogen deposition has a considerable impact on biogeochemical cycling in terrestrial ecosystems.However,how litter production and element return respond to N addition remains poorly understood in nitrogen-rich subtropical regions.In this study,a 4-year nitrogen addition experiment explored its eff ects on foliar litter production and carbon,nitrogen and phosphorus in a subtropical Michelia wilsonii forest.A clear seasonal pattern in foliar litterfall was observed,regardless of nitrogen treatments,with a peak in spring and a smaller one in autumn.Foliar litter increased with increasing nitrogen but did not aff ect litter carbon concentrations and often decreased nitrogen and phosphorous concentrations.The eff ect of nitrogen addition was dependent on time(month/year).Carbon,nitrogen and phosphorous return showed similar bimodal seasonal patterns.Nitrogen addition increased carbon and nitrogen return but did not aff ect phosphorous.Our results suggest that the addition of nitrogen stimulates carbon and nutrient return via litterfall.展开更多
Although pruning is important to obtain highquality,large-diameter timber,the effects of pruning on nonstructural carbohydrates(NSC)in aboveground organs of many timber species are not well understood.Three intensitie...Although pruning is important to obtain highquality,large-diameter timber,the effects of pruning on nonstructural carbohydrates(NSC)in aboveground organs of many timber species are not well understood.Three intensities of pruning(none,moderate and severe)were tested on poplars(Populus alba×P.talassica)in the arid desert region of northwest China to compare the concentrations of soluble sugar(SS),starch(ST)and total nonstructural carbohydrate(TNC)in leaves,branches and trunks during the growing season.The concentration of NSC components after different pruning intensities varied similarly in seasonal patterns,increasing slowly at the beginning of the growing season,continuously declining in the middle,then gradually recovering by the end of the growing season.The monthly mean NSC concentration in poplar differed significantly among the three pruning intensities(p<0.05).The SS concentration in pruned trees was higher than in unpruned trees(p<0.05).For moderately pruned trees,the concentrations of ST and TNC in trunks and branches were higher than in unpruned and in severely pruned trees(p<0.05).Compared with no pruning,pruning changed the seasonal variation in NSC concentration.The orders of SS and TNC concentrations in aboveground organs were leaf>branch>trunk,while the order of ST concentration was trunk>leaf>branch,which was related to functional differences of plant organs.The annual average growth in height of unpruned,moderately pruned,and severely pruned poplars was 0.21±0.06,0.45±0.09 and 0.24±0.05 m,respectively,and the annual average growth in DBH were 0.92±0.04,1.27±0.06 and 1.02±0.05 cm,respectively.Our results demonstrate that moderate pruning may effectively increase the annual growth in tree height and DBH while avoiding damage caused by excessive pruning to the tree body.Therefore,moderate pruning may increase the NSC storage and improve the growth of timber species.展开更多
The purpose of this paper is to develop Advanced Very High Resolution Radiometer(AVHRR)Global Inventory Modelling and Mapping Studies(GIMMS)Normalised Difference Vegetation Index(NDVI;AVHRR GIMMS NDVI for short)based ...The purpose of this paper is to develop Advanced Very High Resolution Radiometer(AVHRR)Global Inventory Modelling and Mapping Studies(GIMMS)Normalised Difference Vegetation Index(NDVI;AVHRR GIMMS NDVI for short)based fraction of absorbed photosynthetically active radiation(FPAR)from 1982 to 2006 and focus on their seasonal and spatial patterns analysis.The available relationship between FPAR and NDVI was used to calculate FPAR values from 1982 to 2006 and validated by Moderate-resolution Imaging Spectroradiometer(MODIS)FPAR product.Then,the seasonal dynamic patterns were analysed,as well as the driving force of climatic factors.Results showed that there was an agreement between FPAR values from this study and those of the MODIS product in seasonal dynamic,and the spatial patterns of FPARvary with vegetation type distribution and seasonal cycles.The time series of average FPAR revealed a strong seasonal variation,regular periodic variations from January 1982 to December 2006,and opposite patterns between the Northern and Southern Hemispheres.Evergreen vegetation FPARvalues were close to 0.7.A clear single-peak curve was observed between 308N and 808N?an area covered by deciduous vegetation.In the Southern Hemisphere,the time series fluctuations of FPAR averaged by 0.78 latitude zones were not clear compared to those in the Northern Hemisphere.A significant positive correlation(PB0.01)was observed between the seasonal variation of temperature and precipitation and FPAR over most other global meteorological sites.展开更多
<span style="font-family:Verdana;">To explore the differences of male semen parameters in different seasons of the year, so as to explore the potential climatic factors affecting spermatogenesis and ma...<span style="font-family:Verdana;">To explore the differences of male semen parameters in different seasons of the year, so as to explore the potential climatic factors affecting spermatogenesis and male reproductive ability</span><span style="font-family:Verdana;">,</span><span style="font-family:;" "=""><span style="font-family:Verdana;"> we retrospectively analyzed 21,715 semen analysis data from January 2018 to February 2021, grouped by year and season, and finally the relationships among semen parameters and semen and meteorological parameters were compared. Environmental exposures prior to 3 months were analyzed and correlation analysis was performed.</span><span style="font-family:Verdana;">The semen concentration decreased year by year (p < 0.01). However, the Progressive motility (PR) and total PR number had been increased (p < 0.01). There were statistical differences in sperm parameters which include semen volume, sperm concentration, total sperm number, progressive motility (PR), total PR number and total motility in different seasons, winter and spring were better than summer and autumn (p < 0.01). Total sperm number and sperm concentration were positively correlated with PR (R = 0.420, R = 0.440, p < 0.01). There was no correlation between daylight duration and semen parameters. Sperm parameters were positively or negatively correlated with environmental temperature, air pressure or humidity which had an overall effect on semen quality. It is suggested that seasonal factors should be considered when evaluating male reproductive ability. Besides referring to conventional semen parameters, other factors such as season and climate should also be considered.</span></span>展开更多
基金supported by a project grant(#2014SZ0151)the Sichuan Bureau of Science and Technologyand in part by a project grant(#094324/Z/10/Z)from the Wellcome Trust(UK).
文摘Background:Human cystic echinococcosis(CE)and alveolar echinococcosis(AE)are highly endemic in Tibetan communities of Sichuan Province.Previous research in the region indicated that domestic dog was the major source of human infection,and observations indicated that domestic dog could have more access to intermediate hosts of Echinococcus spp.:both domestic livestock(CE)viscera and small mammals(AE),in early winter and again in spring.We hypothesized that there would therefore be a significant increase in the risk of canine infection with Echinococcus spp.in these two seasons and conducted a reinfection study to investigate this further.Methods:Faecal samples were collected from owned dogs in seven townships in Ganze Tibetan Autonomous Prefecture(Sichuan Province,China),and Echinococcus spp.infection status was determined using copro-antigen ELISA.Dogs were sampled in April(spring),July(early summer),September/October(autumn/early winter)and December(winter)in 2009;and in April(spring)2010.Dogs were treated with praziquantel following each of the five sample collections to eliminate any tapeworms.Information on dog sex,age and body weight was also collected.The t-test,Fisher’s exact test,Poisson regression and logistic regression were used to compare means and prevalences,and to identify factors associated with infection status.Results:The proportion of female dogs was significantly lower than that of male dogs;female dogs had significantly higher(22.78%)baseline copro-ELISA prevalence than males(11.88%).Dog body weight,sex,age,county and previous infection status at any sampling point had no influence on the re-infection prevalence in general.Poisson regression did not found a significant influence on the re-infection prevalence due to different deworming/sampling time spans.Dogs exhibited significantly higher re-infection prevalences in spring and early summer of 2009 and in early winter between September/October and December of 2009,suggesting a higher infection pressure in these seasons comparing with other seasons.Conclusion:Following praziquantel treatment,dog body weight,sex,age,county,deworming time span and previous infection status at any sampling point had no influence on the re-infection prevalence in the region in general.The differences between re-infection prevalences were probably due to the seasonality in Echinoccocus spp.infection pressure in the region.Early winter,spring and early summer should be important seasons for optimal dog deworming intervention in these Tibetan communities.
文摘The purpose of this paper is to provide understanding of the seasonal pattern of air leakage(infiltration)in Chinese vernacular buildings across China’s five climate regions.In achieving the set purpose,a grand extensive literature survey was conducted and supported with data drawn from established Meteonorm V6.1 on sensible heat and psychrometric variables.Numerical computations for normalized and specific infiltration from stack effects followed the Gowri method in line with ASHRAE reference 2004.Solar energy admittance into building followed Bouger’s model form Angstrom properties.From the distribution of vernacular buildings across five climate regions of China,evidence from computational and numerical values showed symmetries in terms of minimums and maximums times of occurrence.Further,a reciprocal pattern exists between solar radiative admittance and region’s temperature profile.Knowing that Chinese vernacular building heritage extended to further Asia,this research became limited to only the Chinese region.It became difficult to report if the construction culture away from China has correlation with infiltration and energy admittance value.Earlier works on Chinese climate and vernacular dwellings reported a climate responsive dwelling designed by passive cooling strategy;a gap was closed by extending the previous work to specific infiltration pattern and energy admittance level.Chinese vernacular buildings by virtue of research outcomes are and should be adoptable to modern housing needs for cultural integration.
基金supported by the National Natural Science Foundation of China(grants 32071745,32001165,31901295 and 31800519)the Program of Sichuan Excellent Youth Sci-Tech Foundation(2020JDJQ0052)+1 种基金the Applied Basic Research Program of Sichuan of China(2021YJ0340)the National Key Research and Development Program of China(2016YFC0502505 and 2017YFC0505003).
文摘Nitrogen deposition has a considerable impact on biogeochemical cycling in terrestrial ecosystems.However,how litter production and element return respond to N addition remains poorly understood in nitrogen-rich subtropical regions.In this study,a 4-year nitrogen addition experiment explored its eff ects on foliar litter production and carbon,nitrogen and phosphorus in a subtropical Michelia wilsonii forest.A clear seasonal pattern in foliar litterfall was observed,regardless of nitrogen treatments,with a peak in spring and a smaller one in autumn.Foliar litter increased with increasing nitrogen but did not aff ect litter carbon concentrations and often decreased nitrogen and phosphorous concentrations.The eff ect of nitrogen addition was dependent on time(month/year).Carbon,nitrogen and phosphorous return showed similar bimodal seasonal patterns.Nitrogen addition increased carbon and nitrogen return but did not aff ect phosphorous.Our results suggest that the addition of nitrogen stimulates carbon and nutrient return via litterfall.
基金supported by Key Projects of Universities for Foreign Cultural and Educational Experts Employment Plan in 2018(T2018013)granted from Special Funds for Sustainable Development of Science and Technology Platform for Fundamental Research Business Expenses of Central Universities(2572018CP05).
文摘Although pruning is important to obtain highquality,large-diameter timber,the effects of pruning on nonstructural carbohydrates(NSC)in aboveground organs of many timber species are not well understood.Three intensities of pruning(none,moderate and severe)were tested on poplars(Populus alba×P.talassica)in the arid desert region of northwest China to compare the concentrations of soluble sugar(SS),starch(ST)and total nonstructural carbohydrate(TNC)in leaves,branches and trunks during the growing season.The concentration of NSC components after different pruning intensities varied similarly in seasonal patterns,increasing slowly at the beginning of the growing season,continuously declining in the middle,then gradually recovering by the end of the growing season.The monthly mean NSC concentration in poplar differed significantly among the three pruning intensities(p<0.05).The SS concentration in pruned trees was higher than in unpruned trees(p<0.05).For moderately pruned trees,the concentrations of ST and TNC in trunks and branches were higher than in unpruned and in severely pruned trees(p<0.05).Compared with no pruning,pruning changed the seasonal variation in NSC concentration.The orders of SS and TNC concentrations in aboveground organs were leaf>branch>trunk,while the order of ST concentration was trunk>leaf>branch,which was related to functional differences of plant organs.The annual average growth in height of unpruned,moderately pruned,and severely pruned poplars was 0.21±0.06,0.45±0.09 and 0.24±0.05 m,respectively,and the annual average growth in DBH were 0.92±0.04,1.27±0.06 and 1.02±0.05 cm,respectively.Our results demonstrate that moderate pruning may effectively increase the annual growth in tree height and DBH while avoiding damage caused by excessive pruning to the tree body.Therefore,moderate pruning may increase the NSC storage and improve the growth of timber species.
基金funded by the National Basic Research Program of China(contract:2009CB723902),Key Project of Digital Earth Science Platform CEODE(contract:Y01002101A),National Natural Science Foundation of China(contract:41001205/D0106).The authors acknowledge the following data support:the AVHRR GIMMS NDVI from Global Land Cover Facility(GLCF)Globcover products from European Space Agency(ESA)and the ESA Globcover Project led by Medium Resolution Imaging Spectrometer Instrument(MERIS)France+1 种基金temperature,precipitation from National Climatic Data Center(NCDC)MODIS FPAR product from the Warehouse Inventory Search Tool provides access to a complete data record of all MODIS and ASTER products available from the LP DAAC,respectively.
文摘The purpose of this paper is to develop Advanced Very High Resolution Radiometer(AVHRR)Global Inventory Modelling and Mapping Studies(GIMMS)Normalised Difference Vegetation Index(NDVI;AVHRR GIMMS NDVI for short)based fraction of absorbed photosynthetically active radiation(FPAR)from 1982 to 2006 and focus on their seasonal and spatial patterns analysis.The available relationship between FPAR and NDVI was used to calculate FPAR values from 1982 to 2006 and validated by Moderate-resolution Imaging Spectroradiometer(MODIS)FPAR product.Then,the seasonal dynamic patterns were analysed,as well as the driving force of climatic factors.Results showed that there was an agreement between FPAR values from this study and those of the MODIS product in seasonal dynamic,and the spatial patterns of FPARvary with vegetation type distribution and seasonal cycles.The time series of average FPAR revealed a strong seasonal variation,regular periodic variations from January 1982 to December 2006,and opposite patterns between the Northern and Southern Hemispheres.Evergreen vegetation FPARvalues were close to 0.7.A clear single-peak curve was observed between 308N and 808N?an area covered by deciduous vegetation.In the Southern Hemisphere,the time series fluctuations of FPAR averaged by 0.78 latitude zones were not clear compared to those in the Northern Hemisphere.A significant positive correlation(PB0.01)was observed between the seasonal variation of temperature and precipitation and FPAR over most other global meteorological sites.
文摘<span style="font-family:Verdana;">To explore the differences of male semen parameters in different seasons of the year, so as to explore the potential climatic factors affecting spermatogenesis and male reproductive ability</span><span style="font-family:Verdana;">,</span><span style="font-family:;" "=""><span style="font-family:Verdana;"> we retrospectively analyzed 21,715 semen analysis data from January 2018 to February 2021, grouped by year and season, and finally the relationships among semen parameters and semen and meteorological parameters were compared. Environmental exposures prior to 3 months were analyzed and correlation analysis was performed.</span><span style="font-family:Verdana;">The semen concentration decreased year by year (p < 0.01). However, the Progressive motility (PR) and total PR number had been increased (p < 0.01). There were statistical differences in sperm parameters which include semen volume, sperm concentration, total sperm number, progressive motility (PR), total PR number and total motility in different seasons, winter and spring were better than summer and autumn (p < 0.01). Total sperm number and sperm concentration were positively correlated with PR (R = 0.420, R = 0.440, p < 0.01). There was no correlation between daylight duration and semen parameters. Sperm parameters were positively or negatively correlated with environmental temperature, air pressure or humidity which had an overall effect on semen quality. It is suggested that seasonal factors should be considered when evaluating male reproductive ability. Besides referring to conventional semen parameters, other factors such as season and climate should also be considered.</span></span>