This study focuses on analyzing the factors affecting the production and business efficiency of cement manufacturing enterprises in Tuyen Quang province. Production and business efficiency is measured by profitability...This study focuses on analyzing the factors affecting the production and business efficiency of cement manufacturing enterprises in Tuyen Quang province. Production and business efficiency is measured by profitability ratios including return on assets (ROA), return on equity (ROE) and return on sales (ROS). Using a quantitative research method through estimating a linear regression model based on data of two cement manufacturing companies in the period 2019-2021, the research results show that the factors affecting business efficiency of cement manufacturing enterprises in Tuyen Quang province include size of enterprise, cost ratio, average collection period, inventory turnover, fixed assets turnover and debt ratio.展开更多
Background:With increases in global travel and trade,the spread of arboviruses is undoubtedly alarming.Pathogen detection in field-caught mosquitoes can provide the earliest possible warning of transmission.Insect-spe...Background:With increases in global travel and trade,the spread of arboviruses is undoubtedly alarming.Pathogen detection in field-caught mosquitoes can provide the earliest possible warning of transmission.Insect-specific flavivirus(ISFV)has been first detected in 1991 and documented worldwide in the latest ten years.Although infection with ISFVs is apparently limited to insects,an increase in the infection rate of mosquito-borne flaviviruses may be able to induce cytopathic effects in vertebrate cells during co-infection with other human pathogens.However,little is known whether ISFVs persist in most regions of China.Methods:During the mosquito activity season in 2016,a surveillance program was carried out to detect ISFVs in mosquitoes in metropolitan Shanghai,China.The presence of ISFVs was randomly tested in different species of mosquitoes using RT-PCR-based and hemi-nested PCR assays,following by the sequencing of PCR products.Sequences from positive pooled samples were compared with those deposited in GenBank.Thereafter,sequences of representative insect flaviviruses were used for further phylogenetic and molecular evolutionary analyses.Results:Our investigations showed:(1)the presence of Aedes flavivirus(AEFV)in 11/161 pooled samples(nine pools in Songjiang District,one pool in Huangpu District,and one pool in Qingpu District)of Aedes albopictus,(2)the presence of Quang Binh virus(QBV)in 10/195 pooled samples(all in Chongming District)of Culex tritaeniorhynchus;and(3)the presence of Culex flavivirus(CxFV)in 9/228 pooled samples(six pools in Pudong New Area,two pools in Huangpu District,and one pool in Chongming District)of Cx.pipiens.Furthermore,phylogenetic analyses of the gene sequences of envelope proteins indicated that Shanghai CxFV strains belonged to the Asia/USA genotype.The overall maximum likelihood estimation values(and 95%confidence interval)for CxFV,QBV,and AEFV in mosquitoes collected in Shanghai in 2016 were 1.34(0.66-2.45),1.65(0.87-2.85),and 1.51(0.77-2.70)per 1000,respectively.Conclusions:This study reveals the presence and the geographical distribution of ISFVs,and determines the genetic variation and the infection rate of ISFVs in Shanghai,China.At least,three insect flaviviruses including ISFVs,AEFV,CxFV,and QBV,co-circulate in this area.To our knowledge,this is the first report of AEFV in China.展开更多
Agent Blue, a mixture of cacodylic acid (CH<sub>3</sub>) As O<sub>2</sub>H) and sodium cacodylate (C<sub>2</sub>H<sub>6</sub> AsNaO<sub>2</sub>), was a tacti...Agent Blue, a mixture of cacodylic acid (CH<sub>3</sub>) As O<sub>2</sub>H) and sodium cacodylate (C<sub>2</sub>H<sub>6</sub> AsNaO<sub>2</sub>), was a tactical arsenic-based herbicide used during the Vietnam War to destroy grasses and rice crops. Natural and synthetic sources of arsenic can degrade into water-soluble forms and persist in groundwater and potentially contribute to elevating As levels in drinking water. The United States Department of Defense (DOD) and United States Department of Agricultural (USDA) Operation Ranch Hand records for tactical herbicides including Agent Blue sprayed in southern Vietnam during the Vietnam War (1961-1971) are very detailed, rather complete and publicly available. The same is not true for tactical herbicides sprayed by the Republic of Vietnam (RV) during the Khai Quang program which was supported by the U.S. Army, U.S. Navy and Central Intelligence Agency (CIA) in the Mekong Delta. Agent Blue was sprayed by the RV military for three years before the official start of the American-Vietnam War. Few, if any, RV military, US Army, US Navy and CIA spray records exist from 1962 to 1965. Vietnam War veterans, historians and scholars have reported the spraying of 3.2 million liters (468,008 kg As) of Agent Blue on rice paddies and mangrove forests in the Mekong Delta and Central Highlands by the RV military with the support of the US Army, US Navy and CIA. The Institute of Medicine estimated that 3.2 million liters (468,000 kg As) were sprayed during the RV Khai Quang program. This was in addition to the U.S. Air Force’s Operation Ranch Hand spraying of the tactical herbicide Agent Blue primarily by C-123 aircraft. The Operation Ranch Hand missions maintained location and quantities of herbicides sprayed (over 4,712,000 liters (664,392 kg As) from 1961-1971. The RV military and US military (Army and Navy) spray equipment included hand and backpack sprayers, sprayers mounted on Brown Water Navy boats, on Army track vehicles and Army land-based helicopters and helicopters based on the decks of Blue Water Navy ships. Some of these spray missions were a military secret and spray records were classified or if kept were not maintained. Agent Blue containing cacodylic acid had a short half-life and degraded to water-soluble arsenic, which was released into the surface water and/or leached into the groundwater. Once the water-soluble arsenic leached into the Vietnam Mekong Delta groundwater, the arsenic-rich water was pumped back to the surface by tens of thousands of tube wells for urban and agricultural use. The primary objectives of this research are to explore the conditions during the Vietnam War under which 1) the RV military herbicide spray program with the support of the US Navy, CIA and US Army, and 2) the US Air Force spray program during Operation Ranch Hand may have significantly contributed to the natural and anthropic As spikes found in the Mekong Delta today. The environmental impacts of Agent Blue, on the Menominee River at manufacturing sites in the United States, were studied to identify possible As remediation and mitigation strategies. The lessons previously learned at the manufacturing sites in Wisconsin and Michigan, United States can be considered and applied to the Mekong Delta to help mitigate and remediate the arsenic-rich surface water, soil, sediment and groundwater found in the Mekong Delta.展开更多
The central provinces in Vietnam always suffer from the negative impacts of floods every year,especially in the downstream areas.Quang Tri province in the TBRB(Thach Han-Ben Hai River Basin)is one of the provinces suf...The central provinces in Vietnam always suffer from the negative impacts of floods every year,especially in the downstream areas.Quang Tri province in the TBRB(Thach Han-Ben Hai River Basin)is one of the provinces suffering heavy damage caused by floods.A 1-dimensional hydrodynamic model was researched and applied connecting 2 dimensions in the MIKE model set(MIKE FLOOD)to simulate inundation level,inundation time,flood flow velocity for communes in TBRB.Simulation results for 111 communes in Quang Tri province show that:39 communes(35%)are not flooded;3 communes are flooded below 0.5 m;15 communes are flooded from 0.5-1.0 m,flooding time is about 1 day;30 communes are flooded from 1.0-2.0 m,inundation time is about 2 days;30 communes are flooded over 2.0 m,flooded for about 3 days,especially 3 communes are flooded over 4.0 m.This result helps to develop flood prevention plans for localities in the province.展开更多
Background Chongming Island in China serves as a breeding and shelter point on the East Asian–Australasian Flyway.The resting frequency of migratory birds,abundance of mosquito populations,and the popular domestic po...Background Chongming Island in China serves as a breeding and shelter point on the East Asian–Australasian Flyway.The resting frequency of migratory birds,abundance of mosquito populations,and the popular domestic poultry industry pose a potential risk of mosquito-borne zoonotic diseases.The aim of this study is to explore the role of migratory birds in the spread of mosquito-borne pathogens and their prevalent status on the island.Methods We conducted a mosquito-borne pathogen surveillance in 2021,in Chongming,Shanghai,China.Approxi‑mately 67,800 adult mosquitoes belonging to ten species were collected to investigate the presence of faviviruses,alphaviruses,and orthobunyaviruses by RT-PCR.Genetic and phylogenetic analyses were conducted to explore the virus genotype and potential nature source.Serological survey was performed by ELISA to characterize Tembusu virus(TMUV)infection among domestic poultry.Results Two strains of TMUV and Chaoyang virus(CHAOV)and 47 strains of Quang Binh virus(QBV)were detected in 412 mosquito pools,with the infection rate of 0.16,0.16,and 3.92 per 1000 Culex tritaeniorhynchus,respectively.Fur‑thermore,TMUVs viral RNA was found in serum samples of domestic chickens and faecal samples of migratory birds.Antibodies against TMUV were detected in domestic avian serum samples,generally ranging from 44.07%in pigeons to 55.71%in ducks.Phylogenetic analyses indicated that the TMUV detected in Chongming belonged to Cluster 3,Southeast Asia origin,and most closely related to the CTLN strain,which caused a TMUV outbreak in chickens in Guangdong Province in 2020,but distant from strains obtained previously in Shanghai,which were involved in the 2010 TMUV outbreak in China.Conclusions We speculate that the TMUV was imported to Chongming Island through long-distance spreading by migratory birds from Southeast Asia,followed by spill over and transmission in mosquitoes and domestic avian species,threatening the local domestic poultry.In addition,the expansion and prevalence of insect-specifc favivi‑ruses and its simultaneous circulation with mosquito-borne virus are worthy of close attention and further study.展开更多
Fishing with artificial light has become one of the most advanced,efficient,and common methods for the night-time purse seining in Vietnam.This study evaluated the radiation spectrum,CIE chromaticity coordinates,corre...Fishing with artificial light has become one of the most advanced,efficient,and common methods for the night-time purse seining in Vietnam.This study evaluated the radiation spectrum,CIE chromaticity coordinates,correlated color temperature(CCT),catch rate,fuel consumption,and CO_(2)emissions when using Light emitting diode(LED)lamps(0.196 kW)in comparison with the use of metal halide(MH)lights(1 kW)in the offshore purse seine fishery in Quang Tri province,Vietnam.The fishing efficiency of the purse seine fishing boats using LED lamps has increased 1.58 times in catch rate than MH lights,although the energy consumption of LED lamp is 4 times smaller.Fuel consumption of boats per trip using LED lamps was one third of that using MH lights.The use of LED reduced the radiation spectrum,especially the intense UV radiation which negatively affects the health of fishermen.This study also showed the potential of CO_(2)emission reduction up to 1.09 tons of CO_(2)per trip per boat from the use of LED lamps in the offshore purse seine fishing boats.展开更多
文摘This study focuses on analyzing the factors affecting the production and business efficiency of cement manufacturing enterprises in Tuyen Quang province. Production and business efficiency is measured by profitability ratios including return on assets (ROA), return on equity (ROE) and return on sales (ROS). Using a quantitative research method through estimating a linear regression model based on data of two cement manufacturing companies in the period 2019-2021, the research results show that the factors affecting business efficiency of cement manufacturing enterprises in Tuyen Quang province include size of enterprise, cost ratio, average collection period, inventory turnover, fixed assets turnover and debt ratio.
基金This study was supported by the National Key Research and Development Program of China(No.2016YFC1202000,2016YFC1202002,2016YFC1202003)the Fourth Shanghai Public Health Three-Year Action Plan(No.GWIV-29).
文摘Background:With increases in global travel and trade,the spread of arboviruses is undoubtedly alarming.Pathogen detection in field-caught mosquitoes can provide the earliest possible warning of transmission.Insect-specific flavivirus(ISFV)has been first detected in 1991 and documented worldwide in the latest ten years.Although infection with ISFVs is apparently limited to insects,an increase in the infection rate of mosquito-borne flaviviruses may be able to induce cytopathic effects in vertebrate cells during co-infection with other human pathogens.However,little is known whether ISFVs persist in most regions of China.Methods:During the mosquito activity season in 2016,a surveillance program was carried out to detect ISFVs in mosquitoes in metropolitan Shanghai,China.The presence of ISFVs was randomly tested in different species of mosquitoes using RT-PCR-based and hemi-nested PCR assays,following by the sequencing of PCR products.Sequences from positive pooled samples were compared with those deposited in GenBank.Thereafter,sequences of representative insect flaviviruses were used for further phylogenetic and molecular evolutionary analyses.Results:Our investigations showed:(1)the presence of Aedes flavivirus(AEFV)in 11/161 pooled samples(nine pools in Songjiang District,one pool in Huangpu District,and one pool in Qingpu District)of Aedes albopictus,(2)the presence of Quang Binh virus(QBV)in 10/195 pooled samples(all in Chongming District)of Culex tritaeniorhynchus;and(3)the presence of Culex flavivirus(CxFV)in 9/228 pooled samples(six pools in Pudong New Area,two pools in Huangpu District,and one pool in Chongming District)of Cx.pipiens.Furthermore,phylogenetic analyses of the gene sequences of envelope proteins indicated that Shanghai CxFV strains belonged to the Asia/USA genotype.The overall maximum likelihood estimation values(and 95%confidence interval)for CxFV,QBV,and AEFV in mosquitoes collected in Shanghai in 2016 were 1.34(0.66-2.45),1.65(0.87-2.85),and 1.51(0.77-2.70)per 1000,respectively.Conclusions:This study reveals the presence and the geographical distribution of ISFVs,and determines the genetic variation and the infection rate of ISFVs in Shanghai,China.At least,three insect flaviviruses including ISFVs,AEFV,CxFV,and QBV,co-circulate in this area.To our knowledge,this is the first report of AEFV in China.
文摘Agent Blue, a mixture of cacodylic acid (CH<sub>3</sub>) As O<sub>2</sub>H) and sodium cacodylate (C<sub>2</sub>H<sub>6</sub> AsNaO<sub>2</sub>), was a tactical arsenic-based herbicide used during the Vietnam War to destroy grasses and rice crops. Natural and synthetic sources of arsenic can degrade into water-soluble forms and persist in groundwater and potentially contribute to elevating As levels in drinking water. The United States Department of Defense (DOD) and United States Department of Agricultural (USDA) Operation Ranch Hand records for tactical herbicides including Agent Blue sprayed in southern Vietnam during the Vietnam War (1961-1971) are very detailed, rather complete and publicly available. The same is not true for tactical herbicides sprayed by the Republic of Vietnam (RV) during the Khai Quang program which was supported by the U.S. Army, U.S. Navy and Central Intelligence Agency (CIA) in the Mekong Delta. Agent Blue was sprayed by the RV military for three years before the official start of the American-Vietnam War. Few, if any, RV military, US Army, US Navy and CIA spray records exist from 1962 to 1965. Vietnam War veterans, historians and scholars have reported the spraying of 3.2 million liters (468,008 kg As) of Agent Blue on rice paddies and mangrove forests in the Mekong Delta and Central Highlands by the RV military with the support of the US Army, US Navy and CIA. The Institute of Medicine estimated that 3.2 million liters (468,000 kg As) were sprayed during the RV Khai Quang program. This was in addition to the U.S. Air Force’s Operation Ranch Hand spraying of the tactical herbicide Agent Blue primarily by C-123 aircraft. The Operation Ranch Hand missions maintained location and quantities of herbicides sprayed (over 4,712,000 liters (664,392 kg As) from 1961-1971. The RV military and US military (Army and Navy) spray equipment included hand and backpack sprayers, sprayers mounted on Brown Water Navy boats, on Army track vehicles and Army land-based helicopters and helicopters based on the decks of Blue Water Navy ships. Some of these spray missions were a military secret and spray records were classified or if kept were not maintained. Agent Blue containing cacodylic acid had a short half-life and degraded to water-soluble arsenic, which was released into the surface water and/or leached into the groundwater. Once the water-soluble arsenic leached into the Vietnam Mekong Delta groundwater, the arsenic-rich water was pumped back to the surface by tens of thousands of tube wells for urban and agricultural use. The primary objectives of this research are to explore the conditions during the Vietnam War under which 1) the RV military herbicide spray program with the support of the US Navy, CIA and US Army, and 2) the US Air Force spray program during Operation Ranch Hand may have significantly contributed to the natural and anthropic As spikes found in the Mekong Delta today. The environmental impacts of Agent Blue, on the Menominee River at manufacturing sites in the United States, were studied to identify possible As remediation and mitigation strategies. The lessons previously learned at the manufacturing sites in Wisconsin and Michigan, United States can be considered and applied to the Mekong Delta to help mitigate and remediate the arsenic-rich surface water, soil, sediment and groundwater found in the Mekong Delta.
文摘The central provinces in Vietnam always suffer from the negative impacts of floods every year,especially in the downstream areas.Quang Tri province in the TBRB(Thach Han-Ben Hai River Basin)is one of the provinces suffering heavy damage caused by floods.A 1-dimensional hydrodynamic model was researched and applied connecting 2 dimensions in the MIKE model set(MIKE FLOOD)to simulate inundation level,inundation time,flood flow velocity for communes in TBRB.Simulation results for 111 communes in Quang Tri province show that:39 communes(35%)are not flooded;3 communes are flooded below 0.5 m;15 communes are flooded from 0.5-1.0 m,flooding time is about 1 day;30 communes are flooded from 1.0-2.0 m,inundation time is about 2 days;30 communes are flooded over 2.0 m,flooded for about 3 days,especially 3 communes are flooded over 4.0 m.This result helps to develop flood prevention plans for localities in the province.
文摘Background Chongming Island in China serves as a breeding and shelter point on the East Asian–Australasian Flyway.The resting frequency of migratory birds,abundance of mosquito populations,and the popular domestic poultry industry pose a potential risk of mosquito-borne zoonotic diseases.The aim of this study is to explore the role of migratory birds in the spread of mosquito-borne pathogens and their prevalent status on the island.Methods We conducted a mosquito-borne pathogen surveillance in 2021,in Chongming,Shanghai,China.Approxi‑mately 67,800 adult mosquitoes belonging to ten species were collected to investigate the presence of faviviruses,alphaviruses,and orthobunyaviruses by RT-PCR.Genetic and phylogenetic analyses were conducted to explore the virus genotype and potential nature source.Serological survey was performed by ELISA to characterize Tembusu virus(TMUV)infection among domestic poultry.Results Two strains of TMUV and Chaoyang virus(CHAOV)and 47 strains of Quang Binh virus(QBV)were detected in 412 mosquito pools,with the infection rate of 0.16,0.16,and 3.92 per 1000 Culex tritaeniorhynchus,respectively.Fur‑thermore,TMUVs viral RNA was found in serum samples of domestic chickens and faecal samples of migratory birds.Antibodies against TMUV were detected in domestic avian serum samples,generally ranging from 44.07%in pigeons to 55.71%in ducks.Phylogenetic analyses indicated that the TMUV detected in Chongming belonged to Cluster 3,Southeast Asia origin,and most closely related to the CTLN strain,which caused a TMUV outbreak in chickens in Guangdong Province in 2020,but distant from strains obtained previously in Shanghai,which were involved in the 2010 TMUV outbreak in China.Conclusions We speculate that the TMUV was imported to Chongming Island through long-distance spreading by migratory birds from Southeast Asia,followed by spill over and transmission in mosquitoes and domestic avian species,threatening the local domestic poultry.In addition,the expansion and prevalence of insect-specifc favivi‑ruses and its simultaneous circulation with mosquito-borne virus are worthy of close attention and further study.
基金This study was funded by the Hue University DHH 2019-02-109 grant for the project:“Study on the applied LED lamps in offshore seine fishery in Quang Trịprovince”from Hue University,Hue city,Vietnam.
文摘Fishing with artificial light has become one of the most advanced,efficient,and common methods for the night-time purse seining in Vietnam.This study evaluated the radiation spectrum,CIE chromaticity coordinates,correlated color temperature(CCT),catch rate,fuel consumption,and CO_(2)emissions when using Light emitting diode(LED)lamps(0.196 kW)in comparison with the use of metal halide(MH)lights(1 kW)in the offshore purse seine fishery in Quang Tri province,Vietnam.The fishing efficiency of the purse seine fishing boats using LED lamps has increased 1.58 times in catch rate than MH lights,although the energy consumption of LED lamp is 4 times smaller.Fuel consumption of boats per trip using LED lamps was one third of that using MH lights.The use of LED reduced the radiation spectrum,especially the intense UV radiation which negatively affects the health of fishermen.This study also showed the potential of CO_(2)emission reduction up to 1.09 tons of CO_(2)per trip per boat from the use of LED lamps in the offshore purse seine fishing boats.
