Understanding the levels,causes,and sources of fluoride in groundwater is critical for public health,effective water resource management,and sustainable utilization.This study employs multivariate statistical methods,...Understanding the levels,causes,and sources of fluoride in groundwater is critical for public health,effective water resource management,and sustainable utilization.This study employs multivariate statistical methods,hazard quotient assessment,and geochemical analyses,such as mineral saturation index,ionic activities,and Gibbs diagrams,to investigate the hydrochemical characteristics,causes,and noncarcinogenic risks of fluoride in Red bed groundwater and geothermal water in the Guang'an area and neighboring regions.Approximately 9%of the Red bed groundwater samples contain fluoride concentrations exceeding 1 mg·L^(-1).The predominant water types identified are Cl-Na and HCO_(3)-Na,primarily influenced by evapotranspiration.Low-fluoride groundwater and high-fluoride geothermal water exhibit distinct hydrochemical types HCO_(3)-Ca and SO_(4)-Ca,respectively,which are mainly related to the weathering of carbonate,sulfate,and fluorite-containing rocks.Correlation analysis reveals that fluoride content in Red bed groundwater is positively associated with Na^(+),Cl^(-),SO_(4)^(2-),and TDS(r^(2)=0.45-0.64,p<0.01),while in geothermal water,it correlates strongly with pH,K^(+),Ca^(2+),and Mg^(2+)(r^(2)=0.52-0.80,p<0.05).Mineral saturation indices and ionic activities indicate that ion exchange processes and the dissolution of minerals such as carbonatite and fluorite are important sources of fluoride in groundwater.The enrichment of fluorine in the Red bed groundwater is linked to evaporation,cation exchange and dissolution of fluorite,caused by the lithologic characteristics of the red bed in this area.However,it exhibits minimal correlation with the geothermal water in the adjacent area.The noncarcinogenic health risk assessment indicates that 7%(n=5)of Red bed groundwater points exceed the fluoride safety limit for adults,while 12%(n=8)exceed the limit for children.These findings underscore the importance of avoiding highly fluoridated red bed groundwater as a direct drinking source and enhancing groundwater monitoring to mitigate health risks associated with elevated fluoride levels.展开更多
Americans have always been proud of their democratic system. Since the end of World War Ⅱ, the United States has even used its democratic system as a template to “democratize” some other countries. However, in rece...Americans have always been proud of their democratic system. Since the end of World War Ⅱ, the United States has even used its democratic system as a template to “democratize” some other countries. However, in recent years, the domestic democratic chaos in the United States has intensified, causing widespread doubts about the American political system and its democratic model.展开更多
BACKGROUND Mediastinal lymph nodes(MLNs)can be enlarged due to various benign or malignant causes.Endoscopic ultrasound(EUS)is often employed for the acquisition of tissue specimens of the enlarged MLN(EMLN).AIM To de...BACKGROUND Mediastinal lymph nodes(MLNs)can be enlarged due to various benign or malignant causes.Endoscopic ultrasound(EUS)is often employed for the acquisition of tissue specimens of the enlarged MLN(EMLN).AIM To determine the causes,document the symptoms,and determine factors predicting good yield of EUS-guided EMLN biopsy.METHODS All patients having EMLN(>10 mm)on thoracic imaging and referred for EUSguided biopsy were included in this retrospective observational study.Adequacy of the tissue specimen was assessed by the endoscopist with macroscopic on-site evaluation(MOSE)and then sent to a histopathologist for final diagnosis.Analysis for factors predicting good biopsy yield was then performed.RESULTS Of the total 243 patients with EMLN,131(53.9%)were males.The mean age was 47.6(±14.7)and range 14-86 years.Commonest causes of EMLN were tuberculosis 82(33.7%),anthracosis 53(21.8%),neoplastic disease 43(17.7%)and sarcoidosis 14(5.8%).Among the 43 patients with neoplastic diseases:40 had metastatic disease(breast 9,lung 7,pancreatobiliary 6,esophagus 5,kidney 5,hepatocellular 2,neuroendocrine 2,gastrointestinal stromal 1,undetermined 3)and 3 had primary malignancies(lymphoproliferative disorder 2,Kaposi sarcoma 1).Chest related clinical symptoms were absent in more than half the patients with tuberculosis 51/82(62.2%),anthracosis 31/53(58.5%)and neoplastic disease 28/43(65.1%).Factors associated with good biopsy yield were:Subcarinal location of MLN(P=0.026),MLN size>12 mm(P<0.0001),use of fine-needle biopsy(vs fine-needle aspiration)(P=0.049)and satisfactory MOSE(P<0.0001)on univariate analysis;while MLN size>12 mm(P=0.005)and satisfactory MOSE(P<0.0001)on multivariate analysis.CONCLUSION Tuberculosis,anthracosis and metastatic disease were the commonest causes of EMLN.More than half the cases with EMLN had no chest-related symptoms.Large MLN size and satisfactory MOSE observation predicted a good biopsy yield.展开更多
Based on the monitoring data of air quality and conventional meteorological data in Shaoyang City,a severe pollution weather process in Shaoyang from December 25,2023 to January 1,2024 was analyzed from the aspects of...Based on the monitoring data of air quality and conventional meteorological data in Shaoyang City,a severe pollution weather process in Shaoyang from December 25,2023 to January 1,2024 was analyzed from the aspects of changes in pollutant concentration,circulation background,and changes in various meteorological elements.The results show that this severe pollution weather process was a compound pollution process caused by accumulation of local pollutants and transportation of external pollutants,during which the primary pollutant was PM_(2.5).During the accumulation stage,the ground was controlled by a uniform pressure field,and the conditions of atmospheric diffusion were poor.During the outbreak stage,the wind on the ground was from the northeast,which was conducive to the input of upstream pollution clusters into the city.Pollutant concentration was inversely correlated with daily average sea-level pressure,and positively correlated with daily average temperature.Wind speed and direction were closely related to PM_(2.5)concentration.During the accumulation stage,the ground was mainly dominated by weak winds,and the conditions of atmospheric diffusion were poor.During the outbreak stage,the continuous northeastward wind continuously transported upstream pollutants to Shaoyang area.Local pollutants accumulated in the previous stable weather process and the terrain led to the outbreak of local pollution.展开更多
From 10 to 15 April 2025,China experienced a rare persistent extreme wind-dust compound disaster that swept from north to south.Based on observational data,historical disaster records,and situations of various exposed...From 10 to 15 April 2025,China experienced a rare persistent extreme wind-dust compound disaster that swept from north to south.Based on observational data,historical disaster records,and situations of various exposed elements,this study analyzed the formation mechanisms and evolution of this extreme event and conducted a rapid assessment of the associated loss and damage.The results indicate that the direct cause of this extreme wind-dust compound disaster was a strong cold vortex system generated in Mongolia,which moved eastward and southward,combined with the amplification effects of topography and urban structures,and the downward transmission of momentum from higher troposphere.The analysis revealed that approximately 697.47 million people were exposed to strong winds,while about 1,374.54 million people were exposed to high concentrations of PM10.The strong winds also caused varying degrees of damage to buildings,transportation networks,agricultural greenhouses,and forests.Based on vulnerability curves for wind-related loss and damage,it was estimated that the number of victims affected by this extreme wind-dust compound disaster ranged from 0.209 to 1.044 million,with casualties between 5 and 13 individuals.The number of damaged buildings was estimated to be between 2115 and 4607,and the area of affected crops was between 229 and 783 km2.The direct economic losses could reach as high as RMB 0.076–3.501 billion yuan.This study revealed the causes of this extreme wind-dust compound disaster and quantified the disaster loss and impact,providing new insights for the prevention of associated disasters.展开更多
Based on abnormalities in tear film structure and dynamics,dry eye syndrome is primarily classified into five types:aqueous-deficient,mucin-deficient,evaporative/lipid-deficient,tear dynamics disorder,and mixed type.T...Based on abnormalities in tear film structure and dynamics,dry eye syndrome is primarily classified into five types:aqueous-deficient,mucin-deficient,evaporative/lipid-deficient,tear dynamics disorder,and mixed type.The disease has diverse triggers,commonly including:lacrimal gland dysfunction;meibomian gland dysfunction accelerating tear evaporation;reduced blinking due to prolonged electronic device use;contact lens wear interfering with the tear film;medication side effects;environmental factors;hormonal fluctuations;certain ophthalmic surgeries,for example,LASIK.Treatment requires targeting specific pathogenic mechanisms,with the core focus on controlling inflammation,restoring tear film stability,and improving related gland function.展开更多
A survey conducted on the premature bolting of Huarong large leaf mustard from 2018 to 2024 revealed that Huarong large leaf mustard sown in middle August was associated with a higher propensity for premature bolting....A survey conducted on the premature bolting of Huarong large leaf mustard from 2018 to 2024 revealed that Huarong large leaf mustard sown in middle August was associated with a higher propensity for premature bolting. Furthermore, it was observed that the earlier being sown, the greater the rate of premature bolting when being sown prior to middle August. The rate of premature bolting observed in seedlings sown on August 8 was recorded at 35.6%. It was noted that as the age of the seedlings increased, the rate of premature bolting correspondingly increased. There were notable differences in the tolerance of various cultivars to elevated temperatures and prolonged sunlight exposure. For instance, cultivars such as Zhangjie 1 and Sichuan Shaguodi, which exhibit greater heat resistance, did not demonstrate premature bolting when sown in early August. The prolonged exposure to elevated temperatures, drought conditions, and extended periods of sunlight during the seedling stage of Huarong large leaf mustard, coupled with delayed irrigation and transplantation, contributed to the occurrence of premature bolting. The Huarong large leaf mustard, when been sown from late August to early September and transplanted at the appropriate time, exhibited normal growth and development, with no instances of premature bolting observed. It is advisable to select heat-resistant varieties, such as Zhangjie 1, prior to middle August. Huarong large leaf mustard should be sown in early to middle September. Additionally, it is essential to ensure centralized production and timely release of seeds, prompt transplantation and harvesting, and enhance the management of pests and diseases.展开更多
BACKGROUND Unicompartmental knee arthroplasty(UKA)has great advantages in the treatment of unicompartmental knee osteoarthritis,but its revision rate is higher than that of total knee arthroplasty.AIM To summarize and...BACKGROUND Unicompartmental knee arthroplasty(UKA)has great advantages in the treatment of unicompartmental knee osteoarthritis,but its revision rate is higher than that of total knee arthroplasty.AIM To summarize and analyse the causes of revision after UKA.METHODS This is a retrospective case series study in which the reasons for the first revision after UKA are summarized.We analysed the clinical symptoms,medical histories,laboratory test results,imaging examination results and treatment processes of the patients who underwent revision and summarized the reasons for primary revision after UKA.RESULTS A total of 13 patients,including 3 males and 10 females,underwent revision surgery after UKA.The average age of the included patients was 67.62 years.The prosthesis was used for 3 d to 72 months.The main reasons for revision after UKA were improper suturing of the surgical opening(1 patient),osteophytes(2 patients),intra-articular loose bodies(2 patients),tibial prosthesis loosening(2 patients),rheumatoid arthritis(1 patient),gasket dislocation(3 patients),anterior cruciate ligament injury(1 patient),and medial collateral ligament injury with residual bone cement(1 patient).CONCLUSION The causes of primary revision after UKA were gasket dislocation,osteophytes,intra-articular loose bodies and tibial prosthesis loosening.Avoidance of these factors may greatly reduce the rate of revision after UKA,improve patient satisfaction and reduce medical burden.展开更多
In this study,the characteristics and preliminary causes of tropical cyclone remote precipitation(TRP)over China during the period from 1979 to 2020 are investigated.Results indicated that approximately 72.42%of tropi...In this study,the characteristics and preliminary causes of tropical cyclone remote precipitation(TRP)over China during the period from 1979 to 2020 are investigated.Results indicated that approximately 72.42%of tropical cyclones(TCs)in the Western Pacific produce TRP over China.The peak months for TRP are July and August.The four key regions of TRP are the adjacent areas between the Sichuan and Shaanxi Provinces,the northern coast of the Bohai Sea,the coast of the Yellow Sea,and the southern coast area.The typical distance between the station with TRP and the TC center ranges from 1500 to 2500 km.Most of these stations are situated north to 60°west of north of the TC.The south–west water vapor transportation on the west side of the TC is crucial to TRP.TRP has a decreasing trend because of the decrease in the number of TCs that generate TRP.From the perspective of large-scale environmental conditions,a decrease in the integrated horizontal water vapor transport in China' Mainland,the weakening of upward motion at approximately 25°–35°N,which is inconducive to convection,and an increase in low-level vertical wind shear,which is unfavorable for the development of TC in areas with high frequencies of TRP-related TCs,are the factors that result in the decreasing trend of TRP.展开更多
This report provides an overall assessment of land fragmentation problems in East Africa. Many parts of East Africa have become highly fragmented, putting development systems and activities in these areas at risk of c...This report provides an overall assessment of land fragmentation problems in East Africa. Many parts of East Africa have become highly fragmented, putting development systems and activities in these areas at risk of complete collapse. Land fragmentation occurs when land gets converted for agriculture, industrialization, or urbanization, invaded by non-local plants, or enclosed for individual use and by subdividing farmlands into subsequent smaller units called parcels with varying average farm sizes. Fragmentation results from inappropriate agricultural development processes and ineffective land use planning that fails to recognize how farmland is used, and the importance of its interconnected areas. Insecurity of tenure and resource rights are key factors in making this possible. Land fragmentation is one of the key reasons why the ability of most resources in East Africa becomes scarcer, and those remaining become “privatized” by more powerful community members—keen to maintain their access to them. Such individualistic attitudes are new and disadvantage the poorest even further by affecting the traditional customary safety nets and agricultural outputs. Neither the government nor customary governance systems effectively protect resource access for the poorest. This review summary report identifies the key causes, measures, and implications, government interventions, and the common remedies to land fragmentation problems in the East African Countries of Kenya, Uganda, Rwanda, and Tanzania including neighboring Ethiopia, and the Sudan. The findings indicated from 2005 to 2015, the population kept increasing for all the named countries in East Africa with Rwanda and Uganda having a substantial increase in population density. The study review further explores the trend in the performance of agriculture by average farm sizes within the intervals of five years by highlighting their strong linkages and found that the average farm size has declined drastically, especially for Kenya. This can only mean that small farms kept becoming smaller and smaller and that there were more small-scale farmers. The results further depicted that the major and commonly cultivated food crops among the East African countries include maize, sorghum, rice, cassava, sweet potatoes, bananas, Irish potatoes, beans, peas, etc., with maize yields (Mt/ha) in 2003 for Uganda being the highest (1.79 Mt/ha) and the lowest in Rwanda (0.77 Mt/ha) respectively. Therefore, from the review results, recommendations are being made as to how the negative impacts of land fragmentation on agricultural productivity can be reduced or mitigated. One way is by community sensitization and awareness about the importance of land consolidation and its proposition on farm productivity.展开更多
It is an objective fact that the weather is unpredictable.Even the famous meteorologist,Academician Chu Ko Chen,has only a partial understanding of the changing laws of wind and rain.Even though ancient people summari...It is an objective fact that the weather is unpredictable.Even the famous meteorologist,Academician Chu Ko Chen,has only a partial understanding of the changing laws of wind and rain.Even though ancient people summarized the 24 solar terms by observing the annual activities of the sun for a long time,because they ignored the impact of the activities of the moon on the Earth’s climate change on a small scale,the 24 solar terms they summarized often could not accurately predict the change of the Earth’s climate.Therefore,the author studied the influence of lunar activities on the Earth’s climate change,finds out the law of the influence of lunar activities on the Earth’s climate change on a small scale,and summarizes the eternal climate change pattern determined by the activities of the sun and the moon.In addition,the author also reveals the causes and countermeasures of global warming and the frequent occurrence of extreme weather as well as environmental change.展开更多
Fine particulate matter(PM_(2.5))and ozone(O_(3))double high pollution(DHP)events have occurred frequently over China in recent years,but their causes are not completely clear.In this study,the spatiotemporal distribu...Fine particulate matter(PM_(2.5))and ozone(O_(3))double high pollution(DHP)events have occurred frequently over China in recent years,but their causes are not completely clear.In this study,the spatiotemporal distribution of DHP events in China during 2013–20 is analyzed.The synoptic types affecting DHP events are identified with the Lamb–Jenkinson circulation classification method.The meteorological and chemical causes of DHP events controlled by the main synoptic types are further investigated.Results show that DHP events(1655 in total for China during 2013–20)mainly occur over the North China Plain,Yangtze River Delta,Pearl River Delta,Sichuan Basin,and Central China.The occurrence frequency increases by 5.1%during 2013–15,and then decreases by 56.1%during 2015–20.The main circulation types of DHP events are“cyclone”and“anticyclone”,accounting for over 40%of all DHP events over five main polluted regions in China,followed by southerly or easterly flat airflow types,like“southeast”,“southwest”,and“east”.Compared with non-DHP events,DHP events are characterized by static or weak wind,high temperature(20.9℃ versus 23.1℃)and low humidity(70.0%versus 64.9%).The diurnal cycles of meteorological conditions cause PM_(2.5)(0300–1200 LST,Local Standard Time=UTC+8 hours)and O_(3)(1500–2100 LST)to exceed the national standards at different periods of the DHP day.Three pollutant conversion indices further indicate the rapid secondary conversions during DHP events,and thus the concentrations of NO_(2),SO_(2) and volatile organic compounds decrease by 13.1%,4.7%and 4.4%,respectively.The results of this study can be informative for future decisions on the management of DHP events.展开更多
Introduction: Neonatal mortality represents a global health problem that has been at the core of programs developed by the World Health Organization (WHO) for more than 30 years. In our country, it represents a real s...Introduction: Neonatal mortality represents a global health problem that has been at the core of programs developed by the World Health Organization (WHO) for more than 30 years. In our country, it represents a real scourge and remains high despite the efforts made by the Ministry of Health. The goal of this study was to investigate the prevalence and causes of neonatal mortality at CHU-MEL of Cotonou in 2023. Material and Methods: This was a cross-sectional and descriptive study with retrospective data collection, carried out in the neonatology unit of the Mother and Child Teaching Hospital of Lagune (CHU-MEL) in Cotonou over a period of six months from January 1, 2023 to June 30, 2023. All neonates, premature or full-term, born alive and who died during hospitalization in the unit were included. Results: 211 cases of neonatal deaths were recorded among the 2884 neonates hospitalized in the unit during the study period, representing a hospital prevalence of 7.31%. Early neonatal mortality represented 81.5% of cases. The average age at admission was 4.6 days ± 5.3. The average weight of deceased neonates was 1609.08 ± 798.35 g. The most frequent reasons for hospitalization were represented by prematurity (60.66%) and respiratory distress (23.22%), respectively. Prematurity was the leading cause of neonatal mortality (41.7%), followed by neonatal infections (29.4%) and perinatal asphyxia (10.9%). Conclusion: The prevalence of neonatal mortality in the neonatology unit of CHU-MEL is high. Efforts to improve the quality of perinatal care departments must be intensified to reduce this prevalence.展开更多
Environmental problem is one of three major issues of common concern in the world today.Being a developing socialist country,the environmental problems in china are even more prominent,mainly in population expansion,s...Environmental problem is one of three major issues of common concern in the world today.Being a developing socialist country,the environmental problems in china are even more prominent,mainly in population expansion,sharp decrease of global forest areas,soil erosion,acid rain pollution,water pollution and so on.This essay is to introduce the present status,formation causes and hazardous condition of acid rain pollution in china.Some feasible and effective control measures are put forward according to the actual situation in China.展开更多
Cloudy-rainy weather for several days in 2007 was featured with the longest duration and the most serious extent of injury since the time from which there was meteorology observation record in Shandong.The causes of t...Cloudy-rainy weather for several days in 2007 was featured with the longest duration and the most serious extent of injury since the time from which there was meteorology observation record in Shandong.The causes of this process were analyzed in this article in terms of general circulation,character of physical quantity and tropical cyclone.The result showed that the precipitation process was a long wave adjustment process and it took place during the transformation process of general circulation turning from the zonal to the radial.During the cloudy-rainy weather process,the Ural mountain ridge and the Western Pacific subtropical high were more abnormally strong and in the further north than that in any other years.The tropical cyclone in the south of the subtropical cyclone activity was more frequent.There was more shortwave in middle latitudes of Asian.The cold air masses Siberia went down south.The cold air masses joined with the current of air in the Lower Yellow River.This led to the lasting cloudy-rainy weather for several days in Shandong.展开更多
Non-variceal upper gastrointestinal bleeding(NVUGIB)is a common gastroenterological emergency associated with significant morbidity and mortality.Gastroenterologists and other involved clinicians are generally assiste...Non-variceal upper gastrointestinal bleeding(NVUGIB)is a common gastroenterological emergency associated with significant morbidity and mortality.Gastroenterologists and other involved clinicians are generally assisted by international guidelines in its management.However,NVUGIB due to peptic ulcer disease only is mainly addressed by current guidelines,with upper gastrointestinal endoscopy being recommended as the gold standard modality for both diagnosis and treatment.Conversely,the management of rare and extraordinary rare causes of NVUGIB is not covered by current guidelines.Given they are frequently lifethreatening conditions,all the involved clinicians,that is emergency physicians,diagnostic and interventional radiologists,surgeons,in addition obviously to gastroenterologists,should be aware of and familiar with their management.Indeed,they typically require a prompt diagnosis and treatment,engaging a dedicated,patient-tailored,multidisciplinary team approach.The aim of our review was to extensively summarize the current evidence with regard to the management of rare and extraordinary rare causes of NVUGIB.展开更多
After the illustration of the development of quadrangle courtyards,the paper has analyzed the emergence of square architectural form and the formation of axial symmetrical pattern with the hall in the front and room a...After the illustration of the development of quadrangle courtyards,the paper has analyzed the emergence of square architectural form and the formation of axial symmetrical pattern with the hall in the front and room at the back and with wing rooms on the left and right side.It has analyzed the formation,development,climax,damage and inheritance of quadrangle courtyard,and considered that it could manifest Chinese traditional humanistic idea and aesthetic idea,and is in possession of profound cultural connotation and regional feature.On this basis,causes for quadrangle courtyards have been studied.The primary cause at the initial stage lies in human body structure theory and the perfection of quadrangle courtyards at later stage depends on ethic order theory.展开更多
The <strong><em>purpose</em></strong> of this research was to ascertain causes of Restocking Delays in a Distributor Company of Airtel Airtime (<em>AA</em>) that give justification ...The <strong><em>purpose</em></strong> of this research was to ascertain causes of Restocking Delays in a Distributor Company of Airtel Airtime (<em>AA</em>) that give justification for benefits of using Real Time Inventory Tracking (<em>R.T.I.T</em>) in an attempt to mitigate Restocking Delays. From a study out at the Private Marketing and Trading Services (<em>PMTS</em>) an Authorized Distributor of Airtel Products undertaken in 2017 evidenced by Airtime scratch card and Electronic, <strong><em>E-Recharge</em></strong> Airtime among other forms to encourage <em>R.T.I.T</em> among other products in Telecom Companies and other Business Enterprises. The research comprises of the following areas among which included a detailed focus on a <strong><em>Qualitative</em></strong> and <strong><em>Quantitative approach</em></strong> in obtaining different <strong><em>categories</em></strong> of Restocking Delays in form of <strong><em>Themes</em></strong> and <strong><em>Sub Themes</em></strong> encountered in the Distribution Supply Chain (<em>SC</em>) of <em>AA</em> that is contained in this paper. This research continues to capture an in-depth explanation of the <strong><em>Managerial</em></strong> and <strong><em>Operational</em></strong> causes of restocking delays in respect to <em>AA</em>. Similarly, fast consumer products and services other than <em>AA</em> require a solution to <strong><em>Restocking Delays</em></strong> through implementation of Real Time Inventory Tracking Model (<em>R.T.I.T.M</em>) of <em>AA</em> among Distributor Companies (<em>DCs</em>). This paper also elaborated on Literature, Methodology and Findings obtained from the study. The <strong><em>results</em></strong> were obtained from <strong><em>regression analysis</em></strong> by using the Statistical Package for Social Sciences (<em>SPSS</em>) that showed a higher significance of <strong><em>Stock Turnover Period</em></strong> and<strong><em> Airtime Denomination</em></strong> as a contributor to Restocking Delays whereas <strong><em>Messages from Airtel</em></strong> Head office to the Distributor had a non-significant contribution to restocking Delays as in Figure 9. The research recommends a Model for <em>R.T.I.T</em> in Telecom Distribution <em>SC</em> of <em>AA </em>and Omnichannel Inventory Management (<em>OIM</em>) as a significant contributor to timely reliable inventory restocking and promotes higher sales among <em>DCs</em> and retailers through minimized Restocking Delays. It shows that the forces of Demand and Supply change over time with different tastes and preferences of customers. The imbalance in <em>AA</em> stock levels changes at given times due to unforeseen forces of consumer demand experienced by <em>DCs</em>, explained by the “<strong><em>Bullwhip Effect</em></strong>” due to information distortion in the Supply Chain (<em>SC</em>).展开更多
基金supported by the China Geological Survey Project(Nos.DD20220864 and DD20243077).
文摘Understanding the levels,causes,and sources of fluoride in groundwater is critical for public health,effective water resource management,and sustainable utilization.This study employs multivariate statistical methods,hazard quotient assessment,and geochemical analyses,such as mineral saturation index,ionic activities,and Gibbs diagrams,to investigate the hydrochemical characteristics,causes,and noncarcinogenic risks of fluoride in Red bed groundwater and geothermal water in the Guang'an area and neighboring regions.Approximately 9%of the Red bed groundwater samples contain fluoride concentrations exceeding 1 mg·L^(-1).The predominant water types identified are Cl-Na and HCO_(3)-Na,primarily influenced by evapotranspiration.Low-fluoride groundwater and high-fluoride geothermal water exhibit distinct hydrochemical types HCO_(3)-Ca and SO_(4)-Ca,respectively,which are mainly related to the weathering of carbonate,sulfate,and fluorite-containing rocks.Correlation analysis reveals that fluoride content in Red bed groundwater is positively associated with Na^(+),Cl^(-),SO_(4)^(2-),and TDS(r^(2)=0.45-0.64,p<0.01),while in geothermal water,it correlates strongly with pH,K^(+),Ca^(2+),and Mg^(2+)(r^(2)=0.52-0.80,p<0.05).Mineral saturation indices and ionic activities indicate that ion exchange processes and the dissolution of minerals such as carbonatite and fluorite are important sources of fluoride in groundwater.The enrichment of fluorine in the Red bed groundwater is linked to evaporation,cation exchange and dissolution of fluorite,caused by the lithologic characteristics of the red bed in this area.However,it exhibits minimal correlation with the geothermal water in the adjacent area.The noncarcinogenic health risk assessment indicates that 7%(n=5)of Red bed groundwater points exceed the fluoride safety limit for adults,while 12%(n=8)exceed the limit for children.These findings underscore the importance of avoiding highly fluoridated red bed groundwater as a direct drinking source and enhancing groundwater monitoring to mitigate health risks associated with elevated fluoride levels.
文摘Americans have always been proud of their democratic system. Since the end of World War Ⅱ, the United States has even used its democratic system as a template to “democratize” some other countries. However, in recent years, the domestic democratic chaos in the United States has intensified, causing widespread doubts about the American political system and its democratic model.
文摘BACKGROUND Mediastinal lymph nodes(MLNs)can be enlarged due to various benign or malignant causes.Endoscopic ultrasound(EUS)is often employed for the acquisition of tissue specimens of the enlarged MLN(EMLN).AIM To determine the causes,document the symptoms,and determine factors predicting good yield of EUS-guided EMLN biopsy.METHODS All patients having EMLN(>10 mm)on thoracic imaging and referred for EUSguided biopsy were included in this retrospective observational study.Adequacy of the tissue specimen was assessed by the endoscopist with macroscopic on-site evaluation(MOSE)and then sent to a histopathologist for final diagnosis.Analysis for factors predicting good biopsy yield was then performed.RESULTS Of the total 243 patients with EMLN,131(53.9%)were males.The mean age was 47.6(±14.7)and range 14-86 years.Commonest causes of EMLN were tuberculosis 82(33.7%),anthracosis 53(21.8%),neoplastic disease 43(17.7%)and sarcoidosis 14(5.8%).Among the 43 patients with neoplastic diseases:40 had metastatic disease(breast 9,lung 7,pancreatobiliary 6,esophagus 5,kidney 5,hepatocellular 2,neuroendocrine 2,gastrointestinal stromal 1,undetermined 3)and 3 had primary malignancies(lymphoproliferative disorder 2,Kaposi sarcoma 1).Chest related clinical symptoms were absent in more than half the patients with tuberculosis 51/82(62.2%),anthracosis 31/53(58.5%)and neoplastic disease 28/43(65.1%).Factors associated with good biopsy yield were:Subcarinal location of MLN(P=0.026),MLN size>12 mm(P<0.0001),use of fine-needle biopsy(vs fine-needle aspiration)(P=0.049)and satisfactory MOSE(P<0.0001)on univariate analysis;while MLN size>12 mm(P=0.005)and satisfactory MOSE(P<0.0001)on multivariate analysis.CONCLUSION Tuberculosis,anthracosis and metastatic disease were the commonest causes of EMLN.More than half the cases with EMLN had no chest-related symptoms.Large MLN size and satisfactory MOSE observation predicted a good biopsy yield.
文摘Based on the monitoring data of air quality and conventional meteorological data in Shaoyang City,a severe pollution weather process in Shaoyang from December 25,2023 to January 1,2024 was analyzed from the aspects of changes in pollutant concentration,circulation background,and changes in various meteorological elements.The results show that this severe pollution weather process was a compound pollution process caused by accumulation of local pollutants and transportation of external pollutants,during which the primary pollutant was PM_(2.5).During the accumulation stage,the ground was controlled by a uniform pressure field,and the conditions of atmospheric diffusion were poor.During the outbreak stage,the wind on the ground was from the northeast,which was conducive to the input of upstream pollution clusters into the city.Pollutant concentration was inversely correlated with daily average sea-level pressure,and positively correlated with daily average temperature.Wind speed and direction were closely related to PM_(2.5)concentration.During the accumulation stage,the ground was mainly dominated by weak winds,and the conditions of atmospheric diffusion were poor.During the outbreak stage,the continuous northeastward wind continuously transported upstream pollutants to Shaoyang area.Local pollutants accumulated in the previous stable weather process and the terrain led to the outbreak of local pollution.
基金supported by the National Natural Science Foundation of China(Grant No.42330502)the Central Government Guided Local Science and Technology Development Fund of Qinghai Province—Science and Technology Innovation Base Construction Project(Grant No.2025ZY017)。
文摘From 10 to 15 April 2025,China experienced a rare persistent extreme wind-dust compound disaster that swept from north to south.Based on observational data,historical disaster records,and situations of various exposed elements,this study analyzed the formation mechanisms and evolution of this extreme event and conducted a rapid assessment of the associated loss and damage.The results indicate that the direct cause of this extreme wind-dust compound disaster was a strong cold vortex system generated in Mongolia,which moved eastward and southward,combined with the amplification effects of topography and urban structures,and the downward transmission of momentum from higher troposphere.The analysis revealed that approximately 697.47 million people were exposed to strong winds,while about 1,374.54 million people were exposed to high concentrations of PM10.The strong winds also caused varying degrees of damage to buildings,transportation networks,agricultural greenhouses,and forests.Based on vulnerability curves for wind-related loss and damage,it was estimated that the number of victims affected by this extreme wind-dust compound disaster ranged from 0.209 to 1.044 million,with casualties between 5 and 13 individuals.The number of damaged buildings was estimated to be between 2115 and 4607,and the area of affected crops was between 229 and 783 km2.The direct economic losses could reach as high as RMB 0.076–3.501 billion yuan.This study revealed the causes of this extreme wind-dust compound disaster and quantified the disaster loss and impact,providing new insights for the prevention of associated disasters.
文摘Based on abnormalities in tear film structure and dynamics,dry eye syndrome is primarily classified into five types:aqueous-deficient,mucin-deficient,evaporative/lipid-deficient,tear dynamics disorder,and mixed type.The disease has diverse triggers,commonly including:lacrimal gland dysfunction;meibomian gland dysfunction accelerating tear evaporation;reduced blinking due to prolonged electronic device use;contact lens wear interfering with the tear film;medication side effects;environmental factors;hormonal fluctuations;certain ophthalmic surgeries,for example,LASIK.Treatment requires targeting specific pathogenic mechanisms,with the core focus on controlling inflammation,restoring tear film stability,and improving related gland function.
基金Supported by Key R&D Projects of Hunan Provincial Department of Science and Technology"Study on Key Modern Processing Techniques and Product Development of Huarong Mustard"(2023NK2039).
文摘A survey conducted on the premature bolting of Huarong large leaf mustard from 2018 to 2024 revealed that Huarong large leaf mustard sown in middle August was associated with a higher propensity for premature bolting. Furthermore, it was observed that the earlier being sown, the greater the rate of premature bolting when being sown prior to middle August. The rate of premature bolting observed in seedlings sown on August 8 was recorded at 35.6%. It was noted that as the age of the seedlings increased, the rate of premature bolting correspondingly increased. There were notable differences in the tolerance of various cultivars to elevated temperatures and prolonged sunlight exposure. For instance, cultivars such as Zhangjie 1 and Sichuan Shaguodi, which exhibit greater heat resistance, did not demonstrate premature bolting when sown in early August. The prolonged exposure to elevated temperatures, drought conditions, and extended periods of sunlight during the seedling stage of Huarong large leaf mustard, coupled with delayed irrigation and transplantation, contributed to the occurrence of premature bolting. The Huarong large leaf mustard, when been sown from late August to early September and transplanted at the appropriate time, exhibited normal growth and development, with no instances of premature bolting observed. It is advisable to select heat-resistant varieties, such as Zhangjie 1, prior to middle August. Huarong large leaf mustard should be sown in early to middle September. Additionally, it is essential to ensure centralized production and timely release of seeds, prompt transplantation and harvesting, and enhance the management of pests and diseases.
基金Supported by National Natural Science Foundation of China,No.82004386and Guangdong Basic and Applied Basic Research Foundation,No.2022A1515011700.
文摘BACKGROUND Unicompartmental knee arthroplasty(UKA)has great advantages in the treatment of unicompartmental knee osteoarthritis,but its revision rate is higher than that of total knee arthroplasty.AIM To summarize and analyse the causes of revision after UKA.METHODS This is a retrospective case series study in which the reasons for the first revision after UKA are summarized.We analysed the clinical symptoms,medical histories,laboratory test results,imaging examination results and treatment processes of the patients who underwent revision and summarized the reasons for primary revision after UKA.RESULTS A total of 13 patients,including 3 males and 10 females,underwent revision surgery after UKA.The average age of the included patients was 67.62 years.The prosthesis was used for 3 d to 72 months.The main reasons for revision after UKA were improper suturing of the surgical opening(1 patient),osteophytes(2 patients),intra-articular loose bodies(2 patients),tibial prosthesis loosening(2 patients),rheumatoid arthritis(1 patient),gasket dislocation(3 patients),anterior cruciate ligament injury(1 patient),and medial collateral ligament injury with residual bone cement(1 patient).CONCLUSION The causes of primary revision after UKA were gasket dislocation,osteophytes,intra-articular loose bodies and tibial prosthesis loosening.Avoidance of these factors may greatly reduce the rate of revision after UKA,improve patient satisfaction and reduce medical burden.
基金supported by the Postgraduate Research&Practice Innovation Program of Jiangsu Province (No.KYCX22_1136)the National Natural Scientific Foundation of China (No.42275037)+2 种基金the Basic Research Fund of CAMS (No.2023Z016)the Key Laboratory of South China Sea Meteorological Disaster Prevention and Mitigation of Hainan Province (No.SCSF202202)supported by the Jiangsu Collaborative Innovation Center for Climate Change。
文摘In this study,the characteristics and preliminary causes of tropical cyclone remote precipitation(TRP)over China during the period from 1979 to 2020 are investigated.Results indicated that approximately 72.42%of tropical cyclones(TCs)in the Western Pacific produce TRP over China.The peak months for TRP are July and August.The four key regions of TRP are the adjacent areas between the Sichuan and Shaanxi Provinces,the northern coast of the Bohai Sea,the coast of the Yellow Sea,and the southern coast area.The typical distance between the station with TRP and the TC center ranges from 1500 to 2500 km.Most of these stations are situated north to 60°west of north of the TC.The south–west water vapor transportation on the west side of the TC is crucial to TRP.TRP has a decreasing trend because of the decrease in the number of TCs that generate TRP.From the perspective of large-scale environmental conditions,a decrease in the integrated horizontal water vapor transport in China' Mainland,the weakening of upward motion at approximately 25°–35°N,which is inconducive to convection,and an increase in low-level vertical wind shear,which is unfavorable for the development of TC in areas with high frequencies of TRP-related TCs,are the factors that result in the decreasing trend of TRP.
文摘This report provides an overall assessment of land fragmentation problems in East Africa. Many parts of East Africa have become highly fragmented, putting development systems and activities in these areas at risk of complete collapse. Land fragmentation occurs when land gets converted for agriculture, industrialization, or urbanization, invaded by non-local plants, or enclosed for individual use and by subdividing farmlands into subsequent smaller units called parcels with varying average farm sizes. Fragmentation results from inappropriate agricultural development processes and ineffective land use planning that fails to recognize how farmland is used, and the importance of its interconnected areas. Insecurity of tenure and resource rights are key factors in making this possible. Land fragmentation is one of the key reasons why the ability of most resources in East Africa becomes scarcer, and those remaining become “privatized” by more powerful community members—keen to maintain their access to them. Such individualistic attitudes are new and disadvantage the poorest even further by affecting the traditional customary safety nets and agricultural outputs. Neither the government nor customary governance systems effectively protect resource access for the poorest. This review summary report identifies the key causes, measures, and implications, government interventions, and the common remedies to land fragmentation problems in the East African Countries of Kenya, Uganda, Rwanda, and Tanzania including neighboring Ethiopia, and the Sudan. The findings indicated from 2005 to 2015, the population kept increasing for all the named countries in East Africa with Rwanda and Uganda having a substantial increase in population density. The study review further explores the trend in the performance of agriculture by average farm sizes within the intervals of five years by highlighting their strong linkages and found that the average farm size has declined drastically, especially for Kenya. This can only mean that small farms kept becoming smaller and smaller and that there were more small-scale farmers. The results further depicted that the major and commonly cultivated food crops among the East African countries include maize, sorghum, rice, cassava, sweet potatoes, bananas, Irish potatoes, beans, peas, etc., with maize yields (Mt/ha) in 2003 for Uganda being the highest (1.79 Mt/ha) and the lowest in Rwanda (0.77 Mt/ha) respectively. Therefore, from the review results, recommendations are being made as to how the negative impacts of land fragmentation on agricultural productivity can be reduced or mitigated. One way is by community sensitization and awareness about the importance of land consolidation and its proposition on farm productivity.
文摘It is an objective fact that the weather is unpredictable.Even the famous meteorologist,Academician Chu Ko Chen,has only a partial understanding of the changing laws of wind and rain.Even though ancient people summarized the 24 solar terms by observing the annual activities of the sun for a long time,because they ignored the impact of the activities of the moon on the Earth’s climate change on a small scale,the 24 solar terms they summarized often could not accurately predict the change of the Earth’s climate.Therefore,the author studied the influence of lunar activities on the Earth’s climate change,finds out the law of the influence of lunar activities on the Earth’s climate change on a small scale,and summarizes the eternal climate change pattern determined by the activities of the sun and the moon.In addition,the author also reveals the causes and countermeasures of global warming and the frequent occurrence of extreme weather as well as environmental change.
基金supported by the National Natural Science Foundation of China(Grant Nos.41830965 and 41905112)the Key Program of the Ministry of Science and Technology of the People’s Republic of China(Grant No.2019YFC0214703)+2 种基金the Hubei Natural Science Foundation(Grant No.2022CFB027)supported by the State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry(Grant No.LAPC-KF-2023-07)the Key Laboratory of Atmospheric Chemistry,China Meteorological Administration(Grant No.2023B08).
文摘Fine particulate matter(PM_(2.5))and ozone(O_(3))double high pollution(DHP)events have occurred frequently over China in recent years,but their causes are not completely clear.In this study,the spatiotemporal distribution of DHP events in China during 2013–20 is analyzed.The synoptic types affecting DHP events are identified with the Lamb–Jenkinson circulation classification method.The meteorological and chemical causes of DHP events controlled by the main synoptic types are further investigated.Results show that DHP events(1655 in total for China during 2013–20)mainly occur over the North China Plain,Yangtze River Delta,Pearl River Delta,Sichuan Basin,and Central China.The occurrence frequency increases by 5.1%during 2013–15,and then decreases by 56.1%during 2015–20.The main circulation types of DHP events are“cyclone”and“anticyclone”,accounting for over 40%of all DHP events over five main polluted regions in China,followed by southerly or easterly flat airflow types,like“southeast”,“southwest”,and“east”.Compared with non-DHP events,DHP events are characterized by static or weak wind,high temperature(20.9℃ versus 23.1℃)and low humidity(70.0%versus 64.9%).The diurnal cycles of meteorological conditions cause PM_(2.5)(0300–1200 LST,Local Standard Time=UTC+8 hours)and O_(3)(1500–2100 LST)to exceed the national standards at different periods of the DHP day.Three pollutant conversion indices further indicate the rapid secondary conversions during DHP events,and thus the concentrations of NO_(2),SO_(2) and volatile organic compounds decrease by 13.1%,4.7%and 4.4%,respectively.The results of this study can be informative for future decisions on the management of DHP events.
文摘Introduction: Neonatal mortality represents a global health problem that has been at the core of programs developed by the World Health Organization (WHO) for more than 30 years. In our country, it represents a real scourge and remains high despite the efforts made by the Ministry of Health. The goal of this study was to investigate the prevalence and causes of neonatal mortality at CHU-MEL of Cotonou in 2023. Material and Methods: This was a cross-sectional and descriptive study with retrospective data collection, carried out in the neonatology unit of the Mother and Child Teaching Hospital of Lagune (CHU-MEL) in Cotonou over a period of six months from January 1, 2023 to June 30, 2023. All neonates, premature or full-term, born alive and who died during hospitalization in the unit were included. Results: 211 cases of neonatal deaths were recorded among the 2884 neonates hospitalized in the unit during the study period, representing a hospital prevalence of 7.31%. Early neonatal mortality represented 81.5% of cases. The average age at admission was 4.6 days ± 5.3. The average weight of deceased neonates was 1609.08 ± 798.35 g. The most frequent reasons for hospitalization were represented by prematurity (60.66%) and respiratory distress (23.22%), respectively. Prematurity was the leading cause of neonatal mortality (41.7%), followed by neonatal infections (29.4%) and perinatal asphyxia (10.9%). Conclusion: The prevalence of neonatal mortality in the neonatology unit of CHU-MEL is high. Efforts to improve the quality of perinatal care departments must be intensified to reduce this prevalence.
文摘Environmental problem is one of three major issues of common concern in the world today.Being a developing socialist country,the environmental problems in china are even more prominent,mainly in population expansion,sharp decrease of global forest areas,soil erosion,acid rain pollution,water pollution and so on.This essay is to introduce the present status,formation causes and hazardous condition of acid rain pollution in china.Some feasible and effective control measures are put forward according to the actual situation in China.
文摘Cloudy-rainy weather for several days in 2007 was featured with the longest duration and the most serious extent of injury since the time from which there was meteorology observation record in Shandong.The causes of this process were analyzed in this article in terms of general circulation,character of physical quantity and tropical cyclone.The result showed that the precipitation process was a long wave adjustment process and it took place during the transformation process of general circulation turning from the zonal to the radial.During the cloudy-rainy weather process,the Ural mountain ridge and the Western Pacific subtropical high were more abnormally strong and in the further north than that in any other years.The tropical cyclone in the south of the subtropical cyclone activity was more frequent.There was more shortwave in middle latitudes of Asian.The cold air masses Siberia went down south.The cold air masses joined with the current of air in the Lower Yellow River.This led to the lasting cloudy-rainy weather for several days in Shandong.
文摘Non-variceal upper gastrointestinal bleeding(NVUGIB)is a common gastroenterological emergency associated with significant morbidity and mortality.Gastroenterologists and other involved clinicians are generally assisted by international guidelines in its management.However,NVUGIB due to peptic ulcer disease only is mainly addressed by current guidelines,with upper gastrointestinal endoscopy being recommended as the gold standard modality for both diagnosis and treatment.Conversely,the management of rare and extraordinary rare causes of NVUGIB is not covered by current guidelines.Given they are frequently lifethreatening conditions,all the involved clinicians,that is emergency physicians,diagnostic and interventional radiologists,surgeons,in addition obviously to gastroenterologists,should be aware of and familiar with their management.Indeed,they typically require a prompt diagnosis and treatment,engaging a dedicated,patient-tailored,multidisciplinary team approach.The aim of our review was to extensively summarize the current evidence with regard to the management of rare and extraordinary rare causes of NVUGIB.
文摘After the illustration of the development of quadrangle courtyards,the paper has analyzed the emergence of square architectural form and the formation of axial symmetrical pattern with the hall in the front and room at the back and with wing rooms on the left and right side.It has analyzed the formation,development,climax,damage and inheritance of quadrangle courtyard,and considered that it could manifest Chinese traditional humanistic idea and aesthetic idea,and is in possession of profound cultural connotation and regional feature.On this basis,causes for quadrangle courtyards have been studied.The primary cause at the initial stage lies in human body structure theory and the perfection of quadrangle courtyards at later stage depends on ethic order theory.
文摘The <strong><em>purpose</em></strong> of this research was to ascertain causes of Restocking Delays in a Distributor Company of Airtel Airtime (<em>AA</em>) that give justification for benefits of using Real Time Inventory Tracking (<em>R.T.I.T</em>) in an attempt to mitigate Restocking Delays. From a study out at the Private Marketing and Trading Services (<em>PMTS</em>) an Authorized Distributor of Airtel Products undertaken in 2017 evidenced by Airtime scratch card and Electronic, <strong><em>E-Recharge</em></strong> Airtime among other forms to encourage <em>R.T.I.T</em> among other products in Telecom Companies and other Business Enterprises. The research comprises of the following areas among which included a detailed focus on a <strong><em>Qualitative</em></strong> and <strong><em>Quantitative approach</em></strong> in obtaining different <strong><em>categories</em></strong> of Restocking Delays in form of <strong><em>Themes</em></strong> and <strong><em>Sub Themes</em></strong> encountered in the Distribution Supply Chain (<em>SC</em>) of <em>AA</em> that is contained in this paper. This research continues to capture an in-depth explanation of the <strong><em>Managerial</em></strong> and <strong><em>Operational</em></strong> causes of restocking delays in respect to <em>AA</em>. Similarly, fast consumer products and services other than <em>AA</em> require a solution to <strong><em>Restocking Delays</em></strong> through implementation of Real Time Inventory Tracking Model (<em>R.T.I.T.M</em>) of <em>AA</em> among Distributor Companies (<em>DCs</em>). This paper also elaborated on Literature, Methodology and Findings obtained from the study. The <strong><em>results</em></strong> were obtained from <strong><em>regression analysis</em></strong> by using the Statistical Package for Social Sciences (<em>SPSS</em>) that showed a higher significance of <strong><em>Stock Turnover Period</em></strong> and<strong><em> Airtime Denomination</em></strong> as a contributor to Restocking Delays whereas <strong><em>Messages from Airtel</em></strong> Head office to the Distributor had a non-significant contribution to restocking Delays as in Figure 9. The research recommends a Model for <em>R.T.I.T</em> in Telecom Distribution <em>SC</em> of <em>AA </em>and Omnichannel Inventory Management (<em>OIM</em>) as a significant contributor to timely reliable inventory restocking and promotes higher sales among <em>DCs</em> and retailers through minimized Restocking Delays. It shows that the forces of Demand and Supply change over time with different tastes and preferences of customers. The imbalance in <em>AA</em> stock levels changes at given times due to unforeseen forces of consumer demand experienced by <em>DCs</em>, explained by the “<strong><em>Bullwhip Effect</em></strong>” due to information distortion in the Supply Chain (<em>SC</em>).
