The characteristics of water-soluble ions in airborne particulate matter in Beijing were investigated using ion chromatography. The results showed that the total concentrations of ions were 83.7 ± 48.9 μg/m3 in ...The characteristics of water-soluble ions in airborne particulate matter in Beijing were investigated using ion chromatography. The results showed that the total concentrations of ions were 83.7 ± 48.9 μg/m3 in spring, 54.0 ± 17.0 μg/m3 in summer, 54.1 ± 42.9 μg/m3 in autumn, and 88.8 ± 47.7 μg/m3 in winter, respectively. Furthermore, out of all the ions, NO3-,SO42-and NH4＋accounted for 81.2% in spring, 78.5% in summer, 74.6% in autumn, and 76.3%in winter. Mg2＋and Ca2＋were mainly associated with coarse particles, with a peak that ranged from 5.8 to 9.0 μm. Na＋, NH4＋and Cl-had a multi-mode distribution with peaks that ranged from 0.43 to 1.1 μm and 4.7 to 9.0 μm. K＋, NO3-, and SO42-were mainly associated with fine particles, with a peak that ranged from 0.65 to 2.1 μm. The concentrations of Na＋, K＋,Mg2＋, Ca2＋, NH4＋, Cl-, NO3-and SO42-were 2.69, 2.32, 1.01, 4.84, 16.9, 11.8, 42.0, and 44.1 μg/m3 in particulate matter（PM） on foggy days, respectively, which were 1.4 to 7.3 times higher than those on clear days. The concentrations of these ions were 2.40, 1.66, 0.92, 4.95, 17.5,7.00, 32.6, and 34.7 μg/m3 in PM on hazy days, respectively, which were 1.2–5.7 times higher than those on clear days.展开更多
Features of structure and propagation of the 30 to SO day atmospheric oscillations are investigated using the ECMWF analysis of 1980-1983. Evidence is provided to confirm the characteristics of the oscillation in the... Features of structure and propagation of the 30 to SO day atmospheric oscillations are investigated using the ECMWF analysis of 1980-1983. Evidence is provided to confirm the characteristics of the oscillation in the equatorial region. Those in the mid-high latitudes, however, are revealed to be very different from the tropics and pose a strong barotropic structure. Horizontal coherence shows teleconnection patterns which can be identified as EAP and PNA. The wind field of the specified time scale of the oscillation appears as long-lived vortices and vortex pairs. Mid-latitude perturbations propagate clearly westwards, especially during the winter season. In the high latitudes, they propagate westwards in the winter but eastwards in the summer. Meridional propagations are rather different from region to region.展开更多
Size-resolved aerosol samples were collected by MOUDI in four seasons in 2007 in Beijing. The PM10 and PM1.8mass concentrations were 166.0 ± 120.5 and 91.6 ± 69.7 μg/m^3, respectively,throughout the measure...Size-resolved aerosol samples were collected by MOUDI in four seasons in 2007 in Beijing. The PM10 and PM1.8mass concentrations were 166.0 ± 120.5 and 91.6 ± 69.7 μg/m^3, respectively,throughout the measurement, with seasonal variation： nearly two times higher in autumn than in summer and spring. Serious fine particle pollution occurred in winter with the PM1.8/PM10 ratio of 0.63, which was higher than other seasons. The size distribution of PM showed obvious seasonal and diurnal variation, with a smaller fine mode peak in spring and in the daytime. OM（organic matter = 1.6 × OC（organic carbon）） and SIA（secondary inorganic aerosol） were major components of fine particles, while OM, SIA and Ca^2＋were major components in coarse particles. Moreover, secondary components, mainly SOA（secondary organic aerosol） and SIA,accounted for 46%-96% of each size bin in fine particles, which meant that secondary pollution existed all year. Sulfates and nitrates, primarily in the form of（NH4）2SO4, NH4NO3, Ca SO4, Na2SO4 and K2SO4, calculated by the model ISORROPIA II, were major components of the solid phase in fine particles. The PM concentration and size distribution were similar in the four seasons on non-haze days, while large differences occurred on haze days, which indicated seasonal variation of PM concentration and size distribution were dominated by haze days. The SIA concentrations and fractions of nearly all size bins were higher on haze days than on non-haze days, which was attributed to heterogeneous aqueous reactions on haze days in the four seasons.展开更多
In a simple semi-geostropic model on the equatorial β-plane, the theoretical analysis on the 30-60 day oscillation in the tropical atmosphere is further discussed based on the wave-CISK mechanism. The convection hea... In a simple semi-geostropic model on the equatorial β-plane, the theoretical analysis on the 30-60 day oscillation in the tropical atmosphere is further discussed based on the wave-CISK mechanism. The convection heating can excite the CISK-Kelvm wave and CISK-Rossby wave in the tropical atmosphere and they are all the low-frequency modes which drive the activities of 30-60 day oscillation in the tropics. The most favorable conditions to excite the CISK-Kelvin wave and CISK-Rossby wave are indicated: There is convection heating but not very strong in the atmosphere and there is weaker disturbance in the lower troposphere.The influences of vertical shearing of basic flow in the troposphere on the 30-60 day oscillation in the tropics are also discussed.展开更多
Hernia is a common problem of the modern world with its incidence more in developing countries. Inguinal hernia is the most common groin hernia repaired worldwide. With advancement in technology operative techniques o...Hernia is a common problem of the modern world with its incidence more in developing countries. Inguinal hernia is the most common groin hernia repaired worldwide. With advancement in technology operative techniques of repair have also evolved. A Pub Med and COCHRANE database search was accomplished in this regard to establish the current status of laparoscopic inguinal hernia repair in view of recent published literature. Published literature support that laparoscopic hernia repair is best suited for recurrent and bilateral inguinal hernia although it may be offered for primary inguinal hernia if expertise is available.展开更多
The probability distribution of precipitation in the Huaihe basin （HB） is analyzed with the shape and scale parameters of a Gamma distribution. The summer daily precipitation records of 158 meteorological raingauges...The probability distribution of precipitation in the Huaihe basin （HB） is analyzed with the shape and scale parameters of a Gamma distribution. The summer daily precipitation records of 158 meteorological raingauges are applied over the HB during the period of 1980-2007, and the precipitation samples are classified into unconditional rainy days and conditional rainy days which have a dry or wet preceding day over the years. The Kolmogorov-Smirnov （K-S） test and the comparison between the Gamma distribution probability density function and the sample frequency of daily precipitation records of five representative stations are conducted and analyzed. The results show that the HB is a ＂scale-dominated＂ region characterized with large scale parameters of the Gamma distribution, where rainfall is likely to exhibit large variability leading to extreme wet or dry conditions. Fklrther analysis shows that the confluence area of Sha River and Ying River within the stream between Wangjiaba dam and Bengbu station, the eastern branch of the Huaihe River （HR） between Bengbu station and the Hongze Lake, and the downstream area below the Hongze Lake, are all the areas with a high probability of large precipitation under the condition that the rainy day has a dry preceding day. The eastern part of the Yishu River watershed and the region near Wangjiaba dam are the center of a high probability of large precipitation under the condition that the rainy day has a wet preceding day. Moreover, the day following a dry preceding day has a greater probability of small rainfall. The probability distribution of summer daily precipitation of the HB is significantly skewed. The probability distribution could be more applicable if the rainy days are preceded by a dry or wet day.展开更多
The southern coast of the Gulf of Maine in the United States is prone to flooding caused by nor＇easters. A state-of-the-art fully-coupled model, the Simulating WAves Nearshore （SWAN） model with unstructured grids a...The southern coast of the Gulf of Maine in the United States is prone to flooding caused by nor＇easters. A state-of-the-art fully-coupled model, the Simulating WAves Nearshore （SWAN） model with unstructured grids and the ADvanced CIRCulation （ADCIRC） model, was used to study the hydrodynamic response in the Gulf of Maine during the Patriot＇s Day storm of 2007, a notable example of nor＇easters in this area. The model predictions agree well with the observed tide-surges and waves during this storm event. Waves and circulation in the Gulf of Maine were analyzed. The Georges Bank plays an important role in dissipating wave energy through the bottom friction when waves propagate over the bank from offshore to the inner gulf due to its shallow bathymetry. Wave energy dissipation results in decreasing significant wave height （SWH） in the cross-bank direction and wave radiation stress gradient, which in turn induces changes in currents. While the tidal currents are dominant over the Georges Bank and in the Bay of Fundy, the residual currents generated by the meteorological forcing and waves are significant over the Georges Bank and in the coastal area and can reach 0.3 m/s and 0.2 m/s, respectively. In the vicinity of the coast, the longshore current generated by the surface wind stress and wave radiation stress acting parallel to the coastline is inversely proportional to the water depth and will eventually be limited by the bottom friction. The storm surge level reaches 0.8 m along the western periphery of the Gulf of Maine while the wave set-up due to radiation stress variation reaches 0.2 m. Therefore, it is significant to coastal flooding.展开更多
The accumulation of thermal time usually represents the local heat resources to drive crop growth.Maps of temperature-based agro-meteorological indices are commonly generated by the spatial interpolation of data colle...The accumulation of thermal time usually represents the local heat resources to drive crop growth.Maps of temperature-based agro-meteorological indices are commonly generated by the spatial interpolation of data collected from meteorological stations with coarse geographic continuity.To solve the critical problems of estimating air temperature(T a) and filling in missing pixels due to cloudy and low-quality images in growing degree days(GDDs) calculation from remotely sensed data,a novel spatio-temporal algorithm for T a estimation from Terra and Aqua moderate resolution imaging spectroradiometer(MODIS) data was proposed.This is a preliminary study to calculate heat accumulation,expressed in accumulative growing degree days(AGDDs) above 10 ℃,from reconstructed T a based on MODIS land surface temperature(LST) data.The verification results of maximum T a,minimum T a,GDD,and AGDD from MODIS-derived data to meteorological calculation were all satisfied with high correlations over 0.01 significant levels.Overall,MODIS-derived AGDD was slightly underestimated with almost 10% relative error.However,the feasibility of employing AGDD anomaly maps to characterize the 2001-2010 spatio-temporal variability of heat accumulation and estimating the 2011 heat accumulation distribution using only MODIS data was finally demonstrated in the current paper.Our study may supply a novel way to calculate AGDD in heat-related study concerning crop growth monitoring,agricultural climatic regionalization,and agro-meteorological disaster detection at the regional scale.展开更多
The general regression neural network(GRNN) model was proposed to model and predict the length of day(LOD) change, which has very complicated time-varying characteristics. Meanwhile, considering that the axial atmosph...The general regression neural network(GRNN) model was proposed to model and predict the length of day(LOD) change, which has very complicated time-varying characteristics. Meanwhile, considering that the axial atmospheric angular momentum(AAM) function is tightly correlated with the LOD changes, it was introduced into the GRNN prediction model to further improve the accuracy of prediction. Experiments with the observational data of LOD changes show that the prediction accuracy of the GRNN model is 6.1% higher than that of BP network, and after introducing AAM function, the improvement of prediction accuracy further increases to 14.7%. The results show that the GRNN with AAM function is an effective prediction method for LOD changes.展开更多
Hard coal mining in the German Ruhr district has a tradition of more than 200 years. Starting in the south near the river Ruhr with mining of seams near to the surface, mining wandered to the north with coal seams dee...Hard coal mining in the German Ruhr district has a tradition of more than 200 years. Starting in the south near the river Ruhr with mining of seams near to the surface, mining wandered to the north with coal seams deeper and deeper. In the same way all environmental effects of mining wandered from south to north, as there are abandoned mining sites, contaminated areas, burning mining dumps, subsided areas and gas accesses at day ground. This all happened in a very high populated area with more than four million inhabitants. Therefore Germany has a long tradition in solving environmental problems of mining activities. The very good interaction of mine authority, mining companies and the mine workers’ union is the main reason why the problems of decreasing mining activities in Germany were solved without economic, environmental or social hazards.展开更多
How animals allocate their time to various activities has significant consequences for their survival because they reflect the different constraints on time-energy balances. Many ecological variables, such as day leng...How animals allocate their time to various activities has significant consequences for their survival because they reflect the different constraints on time-energy balances. Many ecological variables, such as day length, temperature, food availabil- ity, are supposed to effect on activity budgets allocation of temperate primates. To examine the potential influence of these three variables, the activity budgets ofRhinopithecus bieti was studied at Xiaochangdu, Tibet from June 2003 to March 2005. Pearson correlations were utilized to assess potential relationships between activity budget and day length, food availability and temperature, and stepwise multiple regressions to identify the priority of resting and other activities （activities besides feeding, moving and resting）. Time spent resting and doing ＂other activities＂ is positively related to day length, temperature and food availability. No significant correlations were found between feeding/moving time and any of these variables. This suggests that foraging time （feeding ＋ moving） takes priority over rest and other activities. Day length and foraging time （as independent variables） were related to the time spent in the other two activities besides feeding/moving （as dependent variables）. Both time spent resting and in ＂other activities＂ were highly significant positive functions of day length, with the latter a highly significant negative function of feeding time and moving time. Resting time may therefore be interpreted as taking priority over ＂other activities＂ time. These results provide further evidence of the importance of day length, temperature and food availability to seasonal activity budgets [Current Zoology 56 （6）： 650q559, 2010].展开更多
The photoperiodic control of flowering time is essential for the adaptation of plants to variable environments and for successful reproduction. The identification of genes encoding florigens, which had been elusive bu...The photoperiodic control of flowering time is essential for the adaptation of plants to variable environments and for successful reproduction. The identification of genes encoding florigens, which had been elusive but were supposedly synthesized in leaves and then transmitted to shoot apices to induce floral transitions, has greatly advanced our understanding of the photoperiodic regulation of flowering. Studies on the photoperiodism of Arabidopsis, a model long-day plant, revealed the molecular mechanisms regulating the expression of the Arabidopsis florigen gene FT, which is gradually induced in response to increase in day length. By contrast, in rice, a model short-day plant, the expression of the florigen gene Hd3a （an FTortholog in rice） is regulated in an on/off fashion, with strong induction under short-day conditions and repression under long-day conditions. This critical day length dependence of Hd3a expression enables rice to recognize a slight change in the photoperiod as a trigger to initiate floral induction. Rice possesses a second florigen gene, RFT1, which can be expressed to induce floral transition under non-inductive long-day conditions. The complex transcriptional regulation of florigen genes and the resulting precise control over flowering time provides rice with the adaptability required for a crop species of increasing global importance.展开更多
AIM: To evaluate the applicability and safety of ambulatory laparoscopic cholecystectomy (LC) and to compare day case and overnight stay LC. METHODS: Data were collected retrospectively and consecutively for day case ...AIM: To evaluate the applicability and safety of ambulatory laparoscopic cholecystectomy (LC) and to compare day case and overnight stay LC. METHODS: Data were collected retrospectively and consecutively for day case and overnight stay LC patients from July 1, 2009 to April 30, 2011. Outcomes were analyzed for patient demographics, operation time, blood loss during operation and frequency and reasons for unexpected or prolonged hospitalization in each group. RESULTS: There was no hospital mortality and no patient was readmitted with serious morbidity after discharge. 50 patients received a day case LC and 19 had an overnight stay LC. There was a significant difference in age between both groups (P < 0.02). There were no significant differences between the day case LC performed (n = 41) and failed (n = 9) groups and between the day case LC performed and the one night stay LC (n = 12) groups. There was a significant difference in age between the one night stay and more nights stay LC groups (P < 0.05). Thus, elderly patients showed a tendency to like to stay in hospital rather than being a day case. The proportion of unexpected or prolonged hospitalization was not significantly different between the day case and overnight stay LC groups, when the patient’s request was excluded. CONCLUSION: Day case LC can be performed with a low rate of complications. In overnight stay patients, there are many who could be performed safely as a day case. Moreover, we need to take special care to treat elderly patients.展开更多
基金supported by the National Natural Science Foundation of China (No.41105089)the National Environmental Protection Commonweal Research Project (No.201409073)the Beijing Natural Science Foundation (No.8121002)
文摘The characteristics of water-soluble ions in airborne particulate matter in Beijing were investigated using ion chromatography. The results showed that the total concentrations of ions were 83.7 ± 48.9 μg/m3 in spring, 54.0 ± 17.0 μg/m3 in summer, 54.1 ± 42.9 μg/m3 in autumn, and 88.8 ± 47.7 μg/m3 in winter, respectively. Furthermore, out of all the ions, NO3-,SO42-and NH4＋accounted for 81.2% in spring, 78.5% in summer, 74.6% in autumn, and 76.3%in winter. Mg2＋and Ca2＋were mainly associated with coarse particles, with a peak that ranged from 5.8 to 9.0 μm. Na＋, NH4＋and Cl-had a multi-mode distribution with peaks that ranged from 0.43 to 1.1 μm and 4.7 to 9.0 μm. K＋, NO3-, and SO42-were mainly associated with fine particles, with a peak that ranged from 0.65 to 2.1 μm. The concentrations of Na＋, K＋,Mg2＋, Ca2＋, NH4＋, Cl-, NO3-and SO42-were 2.69, 2.32, 1.01, 4.84, 16.9, 11.8, 42.0, and 44.1 μg/m3 in particulate matter（PM） on foggy days, respectively, which were 1.4 to 7.3 times higher than those on clear days. The concentrations of these ions were 2.40, 1.66, 0.92, 4.95, 17.5,7.00, 32.6, and 34.7 μg/m3 in PM on hazy days, respectively, which were 1.2–5.7 times higher than those on clear days.
文摘 Features of structure and propagation of the 30 to SO day atmospheric oscillations are investigated using the ECMWF analysis of 1980-1983. Evidence is provided to confirm the characteristics of the oscillation in the equatorial region. Those in the mid-high latitudes, however, are revealed to be very different from the tropics and pose a strong barotropic structure. Horizontal coherence shows teleconnection patterns which can be identified as EAP and PNA. The wind field of the specified time scale of the oscillation appears as long-lived vortices and vortex pairs. Mid-latitude perturbations propagate clearly westwards, especially during the winter season. In the high latitudes, they propagate westwards in the winter but eastwards in the summer. Meridional propagations are rather different from region to region.
基金supported by the National Natural Science Foundation of China (Nos. 41175018, 41475113)the special fund of the State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry (No. LAPC-KF-2014-01)
文摘Size-resolved aerosol samples were collected by MOUDI in four seasons in 2007 in Beijing. The PM10 and PM1.8mass concentrations were 166.0 ± 120.5 and 91.6 ± 69.7 μg/m^3, respectively,throughout the measurement, with seasonal variation： nearly two times higher in autumn than in summer and spring. Serious fine particle pollution occurred in winter with the PM1.8/PM10 ratio of 0.63, which was higher than other seasons. The size distribution of PM showed obvious seasonal and diurnal variation, with a smaller fine mode peak in spring and in the daytime. OM（organic matter = 1.6 × OC（organic carbon）） and SIA（secondary inorganic aerosol） were major components of fine particles, while OM, SIA and Ca^2＋were major components in coarse particles. Moreover, secondary components, mainly SOA（secondary organic aerosol） and SIA,accounted for 46%-96% of each size bin in fine particles, which meant that secondary pollution existed all year. Sulfates and nitrates, primarily in the form of（NH4）2SO4, NH4NO3, Ca SO4, Na2SO4 and K2SO4, calculated by the model ISORROPIA II, were major components of the solid phase in fine particles. The PM concentration and size distribution were similar in the four seasons on non-haze days, while large differences occurred on haze days, which indicated seasonal variation of PM concentration and size distribution were dominated by haze days. The SIA concentrations and fractions of nearly all size bins were higher on haze days than on non-haze days, which was attributed to heterogeneous aqueous reactions on haze days in the four seasons.
文摘 In a simple semi-geostropic model on the equatorial β-plane, the theoretical analysis on the 30-60 day oscillation in the tropical atmosphere is further discussed based on the wave-CISK mechanism. The convection heating can excite the CISK-Kelvm wave and CISK-Rossby wave in the tropical atmosphere and they are all the low-frequency modes which drive the activities of 30-60 day oscillation in the tropics. The most favorable conditions to excite the CISK-Kelvin wave and CISK-Rossby wave are indicated: There is convection heating but not very strong in the atmosphere and there is weaker disturbance in the lower troposphere.The influences of vertical shearing of basic flow in the troposphere on the 30-60 day oscillation in the tropics are also discussed.
文摘Hernia is a common problem of the modern world with its incidence more in developing countries. Inguinal hernia is the most common groin hernia repaired worldwide. With advancement in technology operative techniques of repair have also evolved. A Pub Med and COCHRANE database search was accomplished in this regard to establish the current status of laparoscopic inguinal hernia repair in view of recent published literature. Published literature support that laparoscopic hernia repair is best suited for recurrent and bilateral inguinal hernia although it may be offered for primary inguinal hernia if expertise is available.
基金Supported by the China Meteorological Administration Special Public Welfare Research Fund (GYHY201006037,GYHY200906007,and GYHY(QX)2007-6-1)
文摘The probability distribution of precipitation in the Huaihe basin （HB） is analyzed with the shape and scale parameters of a Gamma distribution. The summer daily precipitation records of 158 meteorological raingauges are applied over the HB during the period of 1980-2007, and the precipitation samples are classified into unconditional rainy days and conditional rainy days which have a dry or wet preceding day over the years. The Kolmogorov-Smirnov （K-S） test and the comparison between the Gamma distribution probability density function and the sample frequency of daily precipitation records of five representative stations are conducted and analyzed. The results show that the HB is a ＂scale-dominated＂ region characterized with large scale parameters of the Gamma distribution, where rainfall is likely to exhibit large variability leading to extreme wet or dry conditions. Fklrther analysis shows that the confluence area of Sha River and Ying River within the stream between Wangjiaba dam and Bengbu station, the eastern branch of the Huaihe River （HR） between Bengbu station and the Hongze Lake, and the downstream area below the Hongze Lake, are all the areas with a high probability of large precipitation under the condition that the rainy day has a dry preceding day. The eastern part of the Yishu River watershed and the region near Wangjiaba dam are the center of a high probability of large precipitation under the condition that the rainy day has a wet preceding day. Moreover, the day following a dry preceding day has a greater probability of small rainfall. The probability distribution of summer daily precipitation of the HB is significantly skewed. The probability distribution could be more applicable if the rainy days are preceded by a dry or wet day.
基金supported by the project funded by the Maine Sea Grant and National Oceanic and Atmospheric Administration(Grant No.NA10OAR4170072)the Ensemble Estimation of Flood Risk in a Changing Climate(EFRa CC)project funded by the British Council under its Global Innovation Initiative
文摘The southern coast of the Gulf of Maine in the United States is prone to flooding caused by nor＇easters. A state-of-the-art fully-coupled model, the Simulating WAves Nearshore （SWAN） model with unstructured grids and the ADvanced CIRCulation （ADCIRC） model, was used to study the hydrodynamic response in the Gulf of Maine during the Patriot＇s Day storm of 2007, a notable example of nor＇easters in this area. The model predictions agree well with the observed tide-surges and waves during this storm event. Waves and circulation in the Gulf of Maine were analyzed. The Georges Bank plays an important role in dissipating wave energy through the bottom friction when waves propagate over the bank from offshore to the inner gulf due to its shallow bathymetry. Wave energy dissipation results in decreasing significant wave height （SWH） in the cross-bank direction and wave radiation stress gradient, which in turn induces changes in currents. While the tidal currents are dominant over the Georges Bank and in the Bay of Fundy, the residual currents generated by the meteorological forcing and waves are significant over the Georges Bank and in the coastal area and can reach 0.3 m/s and 0.2 m/s, respectively. In the vicinity of the coast, the longshore current generated by the surface wind stress and wave radiation stress acting parallel to the coastline is inversely proportional to the water depth and will eventually be limited by the bottom friction. The storm surge level reaches 0.8 m along the western periphery of the Gulf of Maine while the wave set-up due to radiation stress variation reaches 0.2 m. Therefore, it is significant to coastal flooding.
基金Project supported by the National Key Technology R&D Program of China (No. 2012BAH29B02)the PhD Programs Foundation of Ministry of Education of China (No. 200100101110035)
文摘The accumulation of thermal time usually represents the local heat resources to drive crop growth.Maps of temperature-based agro-meteorological indices are commonly generated by the spatial interpolation of data collected from meteorological stations with coarse geographic continuity.To solve the critical problems of estimating air temperature(T a) and filling in missing pixels due to cloudy and low-quality images in growing degree days(GDDs) calculation from remotely sensed data,a novel spatio-temporal algorithm for T a estimation from Terra and Aqua moderate resolution imaging spectroradiometer(MODIS) data was proposed.This is a preliminary study to calculate heat accumulation,expressed in accumulative growing degree days(AGDDs) above 10 ℃,from reconstructed T a based on MODIS land surface temperature(LST) data.The verification results of maximum T a,minimum T a,GDD,and AGDD from MODIS-derived data to meteorological calculation were all satisfied with high correlations over 0.01 significant levels.Overall,MODIS-derived AGDD was slightly underestimated with almost 10% relative error.However,the feasibility of employing AGDD anomaly maps to characterize the 2001-2010 spatio-temporal variability of heat accumulation and estimating the 2011 heat accumulation distribution using only MODIS data was finally demonstrated in the current paper.Our study may supply a novel way to calculate AGDD in heat-related study concerning crop growth monitoring,agricultural climatic regionalization,and agro-meteorological disaster detection at the regional scale.
基金Projects(U1231105,10878026)supported by the National Natural Science Foundation of China
文摘The general regression neural network(GRNN) model was proposed to model and predict the length of day(LOD) change, which has very complicated time-varying characteristics. Meanwhile, considering that the axial atmospheric angular momentum(AAM) function is tightly correlated with the LOD changes, it was introduced into the GRNN prediction model to further improve the accuracy of prediction. Experiments with the observational data of LOD changes show that the prediction accuracy of the GRNN model is 6.1% higher than that of BP network, and after introducing AAM function, the improvement of prediction accuracy further increases to 14.7%. The results show that the GRNN with AAM function is an effective prediction method for LOD changes.
文摘Hard coal mining in the German Ruhr district has a tradition of more than 200 years. Starting in the south near the river Ruhr with mining of seams near to the surface, mining wandered to the north with coal seams deeper and deeper. In the same way all environmental effects of mining wandered from south to north, as there are abandoned mining sites, contaminated areas, burning mining dumps, subsided areas and gas accesses at day ground. This all happened in a very high populated area with more than four million inhabitants. Therefore Germany has a long tradition in solving environmental problems of mining activities. The very good interaction of mine authority, mining companies and the mine workers’ union is the main reason why the problems of decreasing mining activities in Germany were solved without economic, environmental or social hazards.
基金supported by the Chinese Academy of Sciences (KSCX2-1-09)the National Natural Science Foundation of China (30870375,31071937)
文摘How animals allocate their time to various activities has significant consequences for their survival because they reflect the different constraints on time-energy balances. Many ecological variables, such as day length, temperature, food availabil- ity, are supposed to effect on activity budgets allocation of temperate primates. To examine the potential influence of these three variables, the activity budgets ofRhinopithecus bieti was studied at Xiaochangdu, Tibet from June 2003 to March 2005. Pearson correlations were utilized to assess potential relationships between activity budget and day length, food availability and temperature, and stepwise multiple regressions to identify the priority of resting and other activities （activities besides feeding, moving and resting）. Time spent resting and doing ＂other activities＂ is positively related to day length, temperature and food availability. No significant correlations were found between feeding/moving time and any of these variables. This suggests that foraging time （feeding ＋ moving） takes priority over rest and other activities. Day length and foraging time （as independent variables） were related to the time spent in the other two activities besides feeding/moving （as dependent variables）. Both time spent resting and in ＂other activities＂ were highly significant positive functions of day length, with the latter a highly significant negative function of feeding time and moving time. Resting time may therefore be interpreted as taking priority over ＂other activities＂ time. These results provide further evidence of the importance of day length, temperature and food availability to seasonal activity budgets [Current Zoology 56 （6）： 650q559, 2010].
文摘The photoperiodic control of flowering time is essential for the adaptation of plants to variable environments and for successful reproduction. The identification of genes encoding florigens, which had been elusive but were supposedly synthesized in leaves and then transmitted to shoot apices to induce floral transitions, has greatly advanced our understanding of the photoperiodic regulation of flowering. Studies on the photoperiodism of Arabidopsis, a model long-day plant, revealed the molecular mechanisms regulating the expression of the Arabidopsis florigen gene FT, which is gradually induced in response to increase in day length. By contrast, in rice, a model short-day plant, the expression of the florigen gene Hd3a （an FTortholog in rice） is regulated in an on/off fashion, with strong induction under short-day conditions and repression under long-day conditions. This critical day length dependence of Hd3a expression enables rice to recognize a slight change in the photoperiod as a trigger to initiate floral induction. Rice possesses a second florigen gene, RFT1, which can be expressed to induce floral transition under non-inductive long-day conditions. The complex transcriptional regulation of florigen genes and the resulting precise control over flowering time provides rice with the adaptability required for a crop species of increasing global importance.
文摘AIM: To evaluate the applicability and safety of ambulatory laparoscopic cholecystectomy (LC) and to compare day case and overnight stay LC. METHODS: Data were collected retrospectively and consecutively for day case and overnight stay LC patients from July 1, 2009 to April 30, 2011. Outcomes were analyzed for patient demographics, operation time, blood loss during operation and frequency and reasons for unexpected or prolonged hospitalization in each group. RESULTS: There was no hospital mortality and no patient was readmitted with serious morbidity after discharge. 50 patients received a day case LC and 19 had an overnight stay LC. There was a significant difference in age between both groups (P < 0.02). There were no significant differences between the day case LC performed (n = 41) and failed (n = 9) groups and between the day case LC performed and the one night stay LC (n = 12) groups. There was a significant difference in age between the one night stay and more nights stay LC groups (P < 0.05). Thus, elderly patients showed a tendency to like to stay in hospital rather than being a day case. The proportion of unexpected or prolonged hospitalization was not significantly different between the day case and overnight stay LC groups, when the patient’s request was excluded. CONCLUSION: Day case LC can be performed with a low rate of complications. In overnight stay patients, there are many who could be performed safely as a day case. Moreover, we need to take special care to treat elderly patients.
