The Dst index has been commonly used to measure the geomagnetic effectiveness of magnetic storm events for several decades.Based on Burton’s empirical Dst model and the global magneto-hydrodynamic(MHD)simulation of E...The Dst index has been commonly used to measure the geomagnetic effectiveness of magnetic storm events for several decades.Based on Burton’s empirical Dst model and the global magneto-hydrodynamic(MHD)simulation of Earth’s magnetosphere,here we proposed a semi-empirical model to forecast the Dst index during geomagnetic storms.In this model,the ring current contribution to the Dst index is derived from Burton’s model,while the contributions from other current systems are obtained from the global MHD simulation.In order to verify the model accuracy,a number of recent magnetic storm events are tested and the simulated Dst index is compared with the observation through the correlation coefficient(CC),prediction efficiency(PE),root mean square error(RMSE)and central root mean square error(CRMSE).The results indicate that,in the context of moderate and intense geomagnetic storm events,the semi-empirical model performs well in global MHD simulations,showing relatively higher CC and PE,and lower RMSE and CRMSE compared to those from the empirical model.Compared with the physics-based ring current models,this model inherits the advantage of fast processing from the empirical model,and easy implementation in a global MHD model of Earth’s magnetosphere.Therefore,it is suitable for the Dst estimation under a context of a global MHD simulation.展开更多
Background:Congenital heart disease(CHD)remains a significant global health concern,with considerable heterogeneity across age groups,genders,and regions.Objective:This study aimed to investigate the global epidemiolo...Background:Congenital heart disease(CHD)remains a significant global health concern,with considerable heterogeneity across age groups,genders,and regions.Objective:This study aimed to investigate the global epidemiological patterns,inequalities,and socio-demographic determinants of CHD burden from 1990 to 2021 to inform targeted interventions.Methods:We utilized data from the Global Burden of Disease 2021 study to assess CHD prevalence,incidence,and mortality rates.Trends were analyzed using Joinpoint regression,age-period-cohort models and autoregressive integrated moving average(ARIMA)forecasting.Health inequality was quantified using the slope index of inequality(SII)and the concentration index(CI),and associations with the Socio-Demographic Index(SDI)were explored.Results:CHD burden increased with age,peaking among individuals aged 70 years and older.This does not reflect new-onset disease,but rather the accumulation of late diagnoses,long-term complications,and healthcare encounters in aging individuals with CHD.Males consistently exhibited higher incidence and mortality rates than females.From 1990 to 2010,global age-standardized prevalence and incidence rates increased steadily and declined slightly thereafter.Joinpoint and age-period-cohort analyses revealed inflection points post-2010 and suggested cohort-related effects.Although SII trends indicated rising inequality over time,that disease burden has become more concentrated in low-SDI regions.ARIMA projections estimated a stable or marginally declining CHD burden by 2030.Regional analyses showed that high-SDI countries experienced significant reductions in CHD mortality,whereas low-SDI regions continued to bear a disproportionate burden.Conclusions:CHD burden has shifted in recent decades,influenced by demographic transitions,healthcare access,and socio-economic development.Despite progress,persistent health inequalities remain.Continued investment in early detection,maternal care,and public health infrastructure is essential to reduce CHD disparities globally.展开更多
A new monsoon index, the dynamical normalized seasonality (DNS), is introduced to study the issue of monsoons. This DNS index can describe both seasonal variation and interannual variability of different monsoon regio...A new monsoon index, the dynamical normalized seasonality (DNS), is introduced to study the issue of monsoons. This DNS index can describe both seasonal variation and interannual variability of different monsoon regions. It can also be used to delimit the geographical distribution of the global monsoon systems. Furthermore, it is pointed out that the index is very useful for understanding deeply the monsoons to study the difference, relationship, and interactions among the classical monsoon, ordinary monsoon and monsoon-like system.展开更多
Objective：To validate malnutrition screening tool of nutrition risk index （NRI） against patent-generated subjective global assessment （PG-SGA） as a gold standard tool in colorectal cancer patients before radiothe...Objective：To validate malnutrition screening tool of nutrition risk index （NRI） against patent-generated subjective global assessment （PG-SGA） as a gold standard tool in colorectal cancer patients before radiotherapy.Methods：Nutritional status of 52 volunteer colorectal cancer patients with a mean age of 54.1±16.8 years who referred to radiotherapy center were assessed by PG-SGA （gold standard method） and NRI.Serum albumin levels of patients were determined by colorimetric method.A contingency table was used to determine the sensitivity,specificity,and predictive value of the NRI in screening patients at risk of malnutrition,in comparison with the PG-SGA in patients before radiotherapy.Results：The findings of PG-SGA and NRI showed that 52％ and 45％ of patients in our study were moderately or severely malnourished respectively.The NRI had a sensitivity of 66％ and a specificity of 60％ against PG-SGA.The positive predictive value was 64％ and the negative predicative value was 62％.The agreement between NRI and PG-SGA was statistically insignificant （kappa =0.267; P＞0.05）.Conclusions：The findings of present study showed that the prevalence of malnutrition was high in patients with colorectal cancer.Moreover,NRI method had low sensitivity and specificity in assessing nutritional status of patients with cancer.It seems that the combination of anthropometric,laboratory parameters and a subjective scoring system may be helpful tools in screening of malnutrition in cancer patients.展开更多
This paper presents the global solar radiation (GSR) and cloud transmittance factor (cf) measured at the horizontal surface over a period of one year from 2009 to 2010 using CMP6 Pyranometer and NILUUV Irradiance Mete...This paper presents the global solar radiation (GSR) and cloud transmittance factor (cf) measured at the horizontal surface over a period of one year from 2009 to 2010 using CMP6 Pyranometer and NILUUV Irradiance Meter at Lukla (Latitude 26.69oN,Longitude 86.73?E and Altitude 2850 m) in the foothills of the Mt Everest (8850 m high). Monthly and seasonal variations of global solar radiation as well as correlation between clearness index and cloud transmittance factor at Lukla are presented. The annual average daily global solar radiation is about 3.83 kWh/sq·m/day which is sufficient to promote solar active and passive energy technology at high mountain terrain where there is no other viable alternative sources of energy. The maximum and minimum global solar radiation of 5.33 and 2.08 kWh/sq·m/day is recorded in April and September 2010 respectively. The seasonal variation of solar energy is about 2.87 kWh/sq·m/day and 4.83 kWh/sq·m/day in summer and spring respectively which is not in line with the general trend. The coefficient of determination (R2) between cloud transmittance factor (cf) and clearness factor (K) is found to be 0.97. This novel result can be utilized to estimate the global solar radiation at the horizontal surface where K and cf are available.展开更多
Crystallographic stability is an important factor that affects the stability of perovskites.The stability dictates the commercial applications of lead-based organometal halide perovskites.The tolerance factor(t)and oc...Crystallographic stability is an important factor that affects the stability of perovskites.The stability dictates the commercial applications of lead-based organometal halide perovskites.The tolerance factor(t)and octahedral factor(μ)form the state-of-the-art criteria used to evaluate the perovskite crystallographic stability.We studied the crystallographic stabilities of halide and chalcogenide perovskites by exploring an effective alternative descriptor,the global instability index(GII)that was used as an indicator of the stability of perovskite oxides.We particularly focused on determining crystallographic reliability by calculating GII.We analyzed the bond valence models of the 243 halide and chalcogenide perovskites that occupied the lowest-energy cubic-phase structures determined by conducting the first-principles-based total energy minimization calculations.The decomposition energy(ΔHD)reflects the thermodynamic stability of the system and is considered as the benchmark that helps assess the effectiveness of GII in evaluating the crystallographic stability of the systems under study.The results indicated that the accuracy of predicting thermodynamic stability was significantly higher when GII(73.6%)was analyzed compared to the cases when t(55%)andμ(39.1%)were analyzed to determine the stability.The results obtained from the machine learning-based data mining method further indicate that GII is an important descriptor of the stability of the perovskite family.展开更多
Time series for the Southern Oscillation Index and mean global near surface temperature anomalies are compared for the 1950 to 2012 period using recently released HadCRU4 data. The method avoids a focused statistical ...Time series for the Southern Oscillation Index and mean global near surface temperature anomalies are compared for the 1950 to 2012 period using recently released HadCRU4 data. The method avoids a focused statistical analysis of the data, in part because the study deals with smoothed data, which means there is the danger of spurious correlations, and in part because the El Ni?o Southern Oscillation is a cyclical phenomenon of irregular period. In these situations the results of regression analysis or similar statistical evaluation can be misleading. With the potential controversy arising over a particular statistical analysis removed, the findings indicate that El Nino-Southern Oscillation exercises a major influence on mean global temperature. The results show the potential of natural forcing mechanisms to account for mean global temperature variation, although the extent of the influence is difficult to quantify from among the variability of short-term influences.展开更多
Objective To compare the value and consistency among the Patient Generated-Subjective Global Assessment(PG-SGA)and the Prognostic Nutrition Index(PNI)for assessing nutritional status in gastrointestinal tumor patients...Objective To compare the value and consistency among the Patient Generated-Subjective Global Assessment(PG-SGA)and the Prognostic Nutrition Index(PNI)for assessing nutritional status in gastrointestinal tumor patients.Methods 251 patients from gastric cancer surgical ward from January 2019 to January 2020 were recruited through convenience sampling in this respective study.Nutritional screening and assessment were conducted for 251 gastrointestinal tumor patients using the nutritional risk screening 2002(NRS 2002)PG-SGA,and the PNI.PNI was calculated using the serum albumin level and the total lymphocyte count obtained from the patients’routine laboratory examination when they were admitted to the hospital.The receiver operating characteristic(ROC)of the PG SGA and the PNI were plotted with the NRS 2002 used as the gold standard,and the diagnostic value of the PG-SGA and PNI was reflected by the area under the curve(AUC),sensitivity,specificity and Youden index.We then determined the optimal cut-off for the PNI and tested the consistency of the PG-SGA and PNI.Results The optimal cut-off point for the PNI was calculated to be 50.78.The AUC of the PG-SGA was 0.908(95%CI 0.871-0.944).The sensitivity was 89.9%,specificity was 76.2%and the Youden index was 0.661.The AUC of the PNI was 0.594(95%CI 0.516-0.572).The sensitivity was 73.8%,specificity was 44.3%and the Youden index was 0.181.In the consistency test,the kappa value was 0.838(P<0.001).Conclusion The PNI is of limited value for assessing malnutrition,although it did have good consistency with the PG-SGA.The combination of the PNI and PG-SGA can be used for diagnosing assessing malnutrition in clinical practice.展开更多
基金supported by NNSFC grants 42150101,42188105,42304189National Key R&D program of China No.2021YFA-0718600the Pandeng Program of National Space Science Center,Chinese Academy of Sciences.
文摘The Dst index has been commonly used to measure the geomagnetic effectiveness of magnetic storm events for several decades.Based on Burton’s empirical Dst model and the global magneto-hydrodynamic(MHD)simulation of Earth’s magnetosphere,here we proposed a semi-empirical model to forecast the Dst index during geomagnetic storms.In this model,the ring current contribution to the Dst index is derived from Burton’s model,while the contributions from other current systems are obtained from the global MHD simulation.In order to verify the model accuracy,a number of recent magnetic storm events are tested and the simulated Dst index is compared with the observation through the correlation coefficient(CC),prediction efficiency(PE),root mean square error(RMSE)and central root mean square error(CRMSE).The results indicate that,in the context of moderate and intense geomagnetic storm events,the semi-empirical model performs well in global MHD simulations,showing relatively higher CC and PE,and lower RMSE and CRMSE compared to those from the empirical model.Compared with the physics-based ring current models,this model inherits the advantage of fast processing from the empirical model,and easy implementation in a global MHD model of Earth’s magnetosphere.Therefore,it is suitable for the Dst estimation under a context of a global MHD simulation.
文摘Background:Congenital heart disease(CHD)remains a significant global health concern,with considerable heterogeneity across age groups,genders,and regions.Objective:This study aimed to investigate the global epidemiological patterns,inequalities,and socio-demographic determinants of CHD burden from 1990 to 2021 to inform targeted interventions.Methods:We utilized data from the Global Burden of Disease 2021 study to assess CHD prevalence,incidence,and mortality rates.Trends were analyzed using Joinpoint regression,age-period-cohort models and autoregressive integrated moving average(ARIMA)forecasting.Health inequality was quantified using the slope index of inequality(SII)and the concentration index(CI),and associations with the Socio-Demographic Index(SDI)were explored.Results:CHD burden increased with age,peaking among individuals aged 70 years and older.This does not reflect new-onset disease,but rather the accumulation of late diagnoses,long-term complications,and healthcare encounters in aging individuals with CHD.Males consistently exhibited higher incidence and mortality rates than females.From 1990 to 2010,global age-standardized prevalence and incidence rates increased steadily and declined slightly thereafter.Joinpoint and age-period-cohort analyses revealed inflection points post-2010 and suggested cohort-related effects.Although SII trends indicated rising inequality over time,that disease burden has become more concentrated in low-SDI regions.ARIMA projections estimated a stable or marginally declining CHD burden by 2030.Regional analyses showed that high-SDI countries experienced significant reductions in CHD mortality,whereas low-SDI regions continued to bear a disproportionate burden.Conclusions:CHD burden has shifted in recent decades,influenced by demographic transitions,healthcare access,and socio-economic development.Despite progress,persistent health inequalities remain.Continued investment in early detection,maternal care,and public health infrastructure is essential to reduce CHD disparities globally.
基金This work was supported jointly by the National Natural Science Foundation of China under Grant Nos. 40233027 and 40275025, and ZKCX2-SW-210.
文摘A new monsoon index, the dynamical normalized seasonality (DNS), is introduced to study the issue of monsoons. This DNS index can describe both seasonal variation and interannual variability of different monsoon regions. It can also be used to delimit the geographical distribution of the global monsoon systems. Furthermore, it is pointed out that the index is very useful for understanding deeply the monsoons to study the difference, relationship, and interactions among the classical monsoon, ordinary monsoon and monsoon-like system.
基金the financial support of Nutrition Research Center,Tabriz University of Medical Sciences
文摘Objective：To validate malnutrition screening tool of nutrition risk index （NRI） against patent-generated subjective global assessment （PG-SGA） as a gold standard tool in colorectal cancer patients before radiotherapy.Methods：Nutritional status of 52 volunteer colorectal cancer patients with a mean age of 54.1±16.8 years who referred to radiotherapy center were assessed by PG-SGA （gold standard method） and NRI.Serum albumin levels of patients were determined by colorimetric method.A contingency table was used to determine the sensitivity,specificity,and predictive value of the NRI in screening patients at risk of malnutrition,in comparison with the PG-SGA in patients before radiotherapy.Results：The findings of PG-SGA and NRI showed that 52％ and 45％ of patients in our study were moderately or severely malnourished respectively.The NRI had a sensitivity of 66％ and a specificity of 60％ against PG-SGA.The positive predictive value was 64％ and the negative predicative value was 62％.The agreement between NRI and PG-SGA was statistically insignificant （kappa =0.267; P＞0.05）.Conclusions：The findings of present study showed that the prevalence of malnutrition was high in patients with colorectal cancer.Moreover,NRI method had low sensitivity and specificity in assessing nutritional status of patients with cancer.It seems that the combination of anthropometric,laboratory parameters and a subjective scoring system may be helpful tools in screening of malnutrition in cancer patients.
文摘This paper presents the global solar radiation (GSR) and cloud transmittance factor (cf) measured at the horizontal surface over a period of one year from 2009 to 2010 using CMP6 Pyranometer and NILUUV Irradiance Meter at Lukla (Latitude 26.69oN,Longitude 86.73?E and Altitude 2850 m) in the foothills of the Mt Everest (8850 m high). Monthly and seasonal variations of global solar radiation as well as correlation between clearness index and cloud transmittance factor at Lukla are presented. The annual average daily global solar radiation is about 3.83 kWh/sq·m/day which is sufficient to promote solar active and passive energy technology at high mountain terrain where there is no other viable alternative sources of energy. The maximum and minimum global solar radiation of 5.33 and 2.08 kWh/sq·m/day is recorded in April and September 2010 respectively. The seasonal variation of solar energy is about 2.87 kWh/sq·m/day and 4.83 kWh/sq·m/day in summer and spring respectively which is not in line with the general trend. The coefficient of determination (R2) between cloud transmittance factor (cf) and clearness factor (K) is found to be 0.97. This novel result can be utilized to estimate the global solar radiation at the horizontal surface where K and cf are available.
基金supported by the National Natural Science Foundation of China(62004080 and 92061113)the Postdoctoral Innovative Talents Supporting Program(BX20190143)the China Postdoctoral Science Foundation(2020M670834)。
文摘Crystallographic stability is an important factor that affects the stability of perovskites.The stability dictates the commercial applications of lead-based organometal halide perovskites.The tolerance factor(t)and octahedral factor(μ)form the state-of-the-art criteria used to evaluate the perovskite crystallographic stability.We studied the crystallographic stabilities of halide and chalcogenide perovskites by exploring an effective alternative descriptor,the global instability index(GII)that was used as an indicator of the stability of perovskite oxides.We particularly focused on determining crystallographic reliability by calculating GII.We analyzed the bond valence models of the 243 halide and chalcogenide perovskites that occupied the lowest-energy cubic-phase structures determined by conducting the first-principles-based total energy minimization calculations.The decomposition energy(ΔHD)reflects the thermodynamic stability of the system and is considered as the benchmark that helps assess the effectiveness of GII in evaluating the crystallographic stability of the systems under study.The results indicated that the accuracy of predicting thermodynamic stability was significantly higher when GII(73.6%)was analyzed compared to the cases when t(55%)andμ(39.1%)were analyzed to determine the stability.The results obtained from the machine learning-based data mining method further indicate that GII is an important descriptor of the stability of the perovskite family.
文摘Time series for the Southern Oscillation Index and mean global near surface temperature anomalies are compared for the 1950 to 2012 period using recently released HadCRU4 data. The method avoids a focused statistical analysis of the data, in part because the study deals with smoothed data, which means there is the danger of spurious correlations, and in part because the El Ni?o Southern Oscillation is a cyclical phenomenon of irregular period. In these situations the results of regression analysis or similar statistical evaluation can be misleading. With the potential controversy arising over a particular statistical analysis removed, the findings indicate that El Nino-Southern Oscillation exercises a major influence on mean global temperature. The results show the potential of natural forcing mechanisms to account for mean global temperature variation, although the extent of the influence is difficult to quantify from among the variability of short-term influences.
文摘Objective To compare the value and consistency among the Patient Generated-Subjective Global Assessment(PG-SGA)and the Prognostic Nutrition Index(PNI)for assessing nutritional status in gastrointestinal tumor patients.Methods 251 patients from gastric cancer surgical ward from January 2019 to January 2020 were recruited through convenience sampling in this respective study.Nutritional screening and assessment were conducted for 251 gastrointestinal tumor patients using the nutritional risk screening 2002(NRS 2002)PG-SGA,and the PNI.PNI was calculated using the serum albumin level and the total lymphocyte count obtained from the patients’routine laboratory examination when they were admitted to the hospital.The receiver operating characteristic(ROC)of the PG SGA and the PNI were plotted with the NRS 2002 used as the gold standard,and the diagnostic value of the PG-SGA and PNI was reflected by the area under the curve(AUC),sensitivity,specificity and Youden index.We then determined the optimal cut-off for the PNI and tested the consistency of the PG-SGA and PNI.Results The optimal cut-off point for the PNI was calculated to be 50.78.The AUC of the PG-SGA was 0.908(95%CI 0.871-0.944).The sensitivity was 89.9%,specificity was 76.2%and the Youden index was 0.661.The AUC of the PNI was 0.594(95%CI 0.516-0.572).The sensitivity was 73.8%,specificity was 44.3%and the Youden index was 0.181.In the consistency test,the kappa value was 0.838(P<0.001).Conclusion The PNI is of limited value for assessing malnutrition,although it did have good consistency with the PG-SGA.The combination of the PNI and PG-SGA can be used for diagnosing assessing malnutrition in clinical practice.
