65 research outputs found
CAMELLIA HOAANA (THEACEAE, SECTION CORALLINA), A NEW SPECIES FROM BU GIA MAP NATIONAL PARK IN SOUTHERN VIETNAM
Camellia hoaana, a new species of the Camellia sect. Corallina (Theaceae) from Bu Gia Map National Park, Vietnam, is described and illustrated. Morphological features of this species are young branches pubescent and glabrescent. Leaves elliptic to obovate-elliptic; apex bluntly cuspidate, base wide cuneate; above dark green, shiny and glabrous; below paler green and sparsely pubescent along midrib; petiole sparsely pubescent. Flowers solitary or geminate, axillary or terminal; pedicel pubescent. Bracteole 1 (or none),pubescent on both sides, persistent. Sepals 4–5(–6), pubescent on both sides, persistent. Petals 5–6, white, outermost 1–2 pubescent at the apex on both sides, the rest glabrous on both sides. Androecium numerous, 2–3 whorls, glabrous. Ovary 3-locular, white silky tomentose; styles 3, free to the base, glabrous. Capsule subglobose, sparsely pubescent, furfuraceous. Seeds 1–2 per locule, semiglobose or globose, densely brown villous. This new species is assessed as Data Deficient (DD) according to the IUCN categories and criteria
Statistical evaluation of the geochemical data for prospecting polymetallic mineralization in the Suoi Thau – Sang Than region, Northeast Vietnam
In Northeast Vietnam, Suoi Thau-Sang Than is considered as a high potential area of polymetallic deposits. 1,720 geochemical samples were used to investigate polymetallic mineralization; thereby polymetallic ore occurrences in this study region were discovered and the statistical and multivariate analysis helps to define geochemical anomalies in some northeastern regions, namely Suoi Thau, Sang Than, and Ban Kep. The statistical method and cluster analysis of geochemical data indicate that the Cu, Pb, and Zn elements are good indicators, and most of them comply with the lognormal or gamma distribution. Based on the third-order threshold, the geochemical anomalies of the content of the Cu, Pb, and Zn elements reflect the concentration of copper forming ore bodies in the mineralized zone, and clearly show the concentration in three distinct zones. The trend surface analysis which was employed to determine spatial variations and relationships among these good indicator elements and anomalous areas revealed relative changes in the content of the indicator elements, and they can be considered as regular. Moreover, the goodness of fit obtained trend functions of Pb and Zn, and Cu elements is a third-degree trend surface model. These results indicate that the models can be useful in studying geochemical anomalies and analyzing the tendency of the concentration of indicator elements in the Suoi Thau-Sang Than region. Additionally, it is suggested that the statistical analysis shows a remarkable potential to use the bottom river sediments in the region to investigate polymetallic mineralization. Moreover, geochemical data can help to evaluate geochemical anomalies of the pathfinder elements and potential mineral mapping of the Suoi Thau-Sang Than region in Northeast Vietnam
Rainfall variability and internal migration: the importance of agriculture linkage and gender inequality
This paper investigates the extent to which exposure to climate volatility can in-fluence individual migration decisions in Vietnam, based on the historical rainfall data from 70 weather stations in Vietnam and the Vietnam Access to Resources House-hold Survey. Utilizing the exogenous variation in the rainfall deviation from the local norms within an individual fixed-effects framework, we uncover the negative associa-tion between rainfall and the probability of individual migration. Individual migration probability drops by 7.5 percentage points when the amount of rainfall relative to the long-run local average doubles. This reduction could potentially be driven by individ-uals who work in the agricultural sector and are less likely to migrate as more rainfall could increase their agricultural incomes. Furthermore, our heterogeneity analyses sug-gest that rainfall shocks could perpetuate gender inequality in Vietnam since women cannot cope with climatic shocks through migration. Policy-makers could shift their focus on flood control and water management in affected areas, where people’s liveli-hoods depend on agriculture, to efficiently address issues related to climate-induced internal migration
Geology, Pb and S Isotope Geochemistry, and Genesis of the Na Bop-Pu Sap Lead-Zinc Deposit in the Cho Don area, Northeastern Vietnam
The Na Bop-Pu Sap Pb-Zn ore bodies represent a typical vein-type lead-zinc deposit situated in the Cho Don area and are currently being extracted for their lead and zinc resources. This deposit is characterized by its significant scale and quality and is considered one of the prominent lead-zinc deposits in the Cho Don area. Despite its significance, this deposit has not received adequate attention, resulting in limited knowledge of its geology, mineralization, and deposit genesis model. To address this knowledge gap, our study utilized several methodologies, including field surveying, ore mineral analysis under a microscope, and S and Pb isotopic geochemistry. By employing these approaches, we were able to obtain specific insights into the origin of mineralization and the deposit model. Our field survey suggests that the ore deposits are formed as Pb-Zn-bearing veins along Devonian shale, claystone, and limestone faults. Microscopic analyses of the veins reveal the presence of galena, sphalerite, chalcopyrite, pyrite, arsenopyrite, and pyrrhotite as ore minerals, and quartz, calcite, dolomite, and chalcedony as gangue minerals. Sulfur-isotope values (δ34SCDT) of galena 5.3 to 0.1‰ (average 2.8‰), sphalerite 6.8 to 2.5‰ (average 5.3‰), and pyrite 5.8 to 4.1‰ (average 4.9‰) indicate that the sulfide mineralization may be related to a deep source, possibly originating from magmatic activity in the region and contaminated by carbonate-bearing marine sedimentary rocks. Lead-isotope studies indicate a model age of 598-424 Ma for the lead reservoir, consistent with the possible presence of local source rocks containing sulfur. The lead and sulfur in the ore veins were probably contaminated by Devonian carbonate-bearing marine sedimentary rocks and leached from Neoproterozoic to Cambrian magmatic activity. The lead-zinc deposits in Na Bop-Pu Sap do not display any Mississippi valley-type (MVT) or Sedimentary exhalative (SEDEX) lead-zinc deposit characteristics, as they appear to be related to shear zone-hosted lead-zinc deposits
PATHOGENICITY OF EIMERIA SPECIES ISOLATED FROM CHICKEN IN THUA THIEN HUE PROVINCE
Abstract: The present study clarifies the effect of locally isolated Eimeria species on chickens in central Vietnam. Oocysts of Eimeria species were isolated from feces suspected to be infected with coccidiosis in 3 farms in Huong Thuy district, Thua Thien Hue province. A total of 54 2-week-old chickens were randomly allocated to 2 groups: 3 replicates containing 9 chickens in each replicate. The chicken in group 1 were orally inoculated with 2×104 isolated oocysts of Eimeria species, while the chickens in group 2 were inoculated with PBS as a control. Growth performance, oocyst output, gross lesions, and histopathological lesions were measured at 5, 10 and 28 days after infection. The chicks in group 1 showed general signs of ruffled feathers, anorexia, huddling together with diarrhea and/or bloody dropping from 4–7 days post-infection. Feed intake, growth performance and body weight in group 1 were lower than those of the control chicks. The oocyst was detected in the feces of chicks in group 1 from 6–14 days post-infection, among them, the number of oocysts reach the peak at 8 days post-infection. At day 5 post-infection, the most damaged part of the intestine is the ceca with a large amount of blood in the ceca content. The histopathological lesions were detected clearly by HE staining at day 5 and 10 post-infection. In conclusion, the locally isolated oocysts of Eimeria species have high virulence to the chickens. The present study provides useful information related to the pathogenicity of Eimeria species which may contribute to coccidiosis diagnosis and treatment in poultry production.Keywords: Eimeria, coccidiosis, infection, central Vietna
Extreme temperature impairs growth and productivity in a common tropical marine copepod
Abstract Shallow, tropical marine ecosystems provide essential ecosystem goods and services, but it is unknown how these ecosystems will respond to the increased exposure to the temperature extremes that are likely to become more common as climate change progresses. To address this issue, we tracked the fitness and productivity of a key zooplankton species, the copepod Pseudodiaptomus annandalei, acclimated at two temperatures (30 and 34 °C) over three generations. 30 °C is the mean temperature in the shallow water of the coastal regions in Southeast Asia, while 34 °C simulated a temperature extreme that occurs frequently during the summer period. For each generation, we measured the size at maturity and reproductive success of individuals. In all three generations, we found strong negative effects of warming on all measured fitness-related parameters, including prolonged development time, reduced size at maturity, smaller clutch sizes, lower hatching success, and reduced naupliar production. Our results suggest that P. annandalei are already exposed to temperatures that exceed their upper thermal optimum. Increased exposure to extreme temperatures may reduce the abundance of these tropical marine copepods, and thus reduce the availability of resources to higher trophic levels
Antibiotic use and prescription and its effects on Enterobacteriaceae in the gut in children with mild respiratory infections in Ho Chi Minh City, Vietnam. A prospective observational outpatient study.
BACKGROUND AND OBJECTIVES: Treatment guidelines do not recommend antibiotic use for acute respiratory infections (ARI), except for streptococcal pharyngitis/tonsillitis and pneumonia. However, antibiotics are prescribed frequently for children with ARI, often in absence of evidence for bacterial infection. The objectives of this study were 1) to assess the appropriateness of antibiotic prescriptions for mild ARI in paediatric outpatients in relation to available guidelines and detected pathogens, 2) to assess antibiotic use on presentation using questionnaires and detection in urine 3) to assess the carriage rates and proportions of resistant intestinal Enterobacteriaceae before, during and after consultation. MATERIALS AND METHODS: Patients were prospectively enrolled in Children's Hospital 1, Ho Chi Minh City, Vietnam and diagnoses, prescribed therapy and outcome were recorded on first visit and on follow-up after 7 days. Respiratory bacterial and viral pathogens were detected using molecular assays. Antibiotic use before presentation was assessed using questionnaires and urine HPLC. The impact of antibiotic usage on intestinal Enterobacteriaceae was assessed with semi-quantitative culture on agar with and without antibiotics on presentation and after 7 and 28 days. RESULTS: A total of 563 patients were enrolled between February 2009 and February 2010. Antibiotics were prescribed for all except 2 of 563 patients. The majority were 2nd and 3rd generation oral cephalosporins and amoxicillin with or without clavulanic acid. Respiratory viruses were detected in respiratory specimens of 72.5% of patients. Antibiotic use was considered inappropriate in 90.1% and 67.5%, based on guidelines and detected pathogens, respectively. On presentation parents reported antibiotic use for 22% of patients, 41% of parents did not know and 37% denied antibiotic use. Among these three groups, six commonly used antibiotics were detected with HPLC in patients' urine in 49%, 40% and 14%, respectively. Temporary selection of 3rd generation cephalosporin resistant intestinal Enterobacteriaceae during antibiotic use was observed, with co-selection of resistance to aminoglycosides and fluoroquinolones. CONCLUSIONS: We report overuse and overprescription of antibiotics for uncomplicated ARI with selection of resistant intestinal Enterobacteriaceae, posing a risk for community transmission and persistence in a setting of a highly granular healthcare system and unrestricted access to antibiotics through private pharmacies. REGISTRATION: This study was registered at the International Standard Randomised Controlled Trials Number registry under number ISRCTN32862422: http://www.isrctn.com/ISRCTN32862422
Height and body-mass index trajectories of school-aged children and adolescents from 1985 to 2019 in 200 countries and territories: a pooled analysis of 2181 population-based studies with 65 million participants
Summary Background Comparable global data on health and nutrition of school-aged children and adolescents are scarce. We aimed to estimate age trajectories and time trends in mean height and mean body-mass index (BMI), which measures weight gain beyond what is expected from height gain, for school-aged children and adolescents. Methods For this pooled analysis, we used a database of cardiometabolic risk factors collated by the Non-Communicable Disease Risk Factor Collaboration. We applied a Bayesian hierarchical model to estimate trends from 1985 to 2019 in mean height and mean BMI in 1-year age groups for ages 5–19 years. The model allowed for non-linear changes over time in mean height and mean BMI and for non-linear changes with age of children and adolescents, including periods of rapid growth during adolescence. Findings We pooled data from 2181 population-based studies, with measurements of height and weight in 65 million participants in 200 countries and territories. In 2019, we estimated a difference of 20 cm or higher in mean height of 19-year-old adolescents between countries with the tallest populations (the Netherlands, Montenegro, Estonia, and Bosnia and Herzegovina for boys; and the Netherlands, Montenegro, Denmark, and Iceland for girls) and those with the shortest populations (Timor-Leste, Laos, Solomon Islands, and Papua New Guinea for boys; and Guatemala, Bangladesh, Nepal, and Timor-Leste for girls). In the same year, the difference between the highest mean BMI (in Pacific island countries, Kuwait, Bahrain, The Bahamas, Chile, the USA, and New Zealand for both boys and girls and in South Africa for girls) and lowest mean BMI (in India, Bangladesh, Timor-Leste, Ethiopia, and Chad for boys and girls; and in Japan and Romania for girls) was approximately 9–10 kg/m2. In some countries, children aged 5 years started with healthier height or BMI than the global median and, in some cases, as healthy as the best performing countries, but they became progressively less healthy compared with their comparators as they grew older by not growing as tall (eg, boys in Austria and Barbados, and girls in Belgium and Puerto Rico) or gaining too much weight for their height (eg, girls and boys in Kuwait, Bahrain, Fiji, Jamaica, and Mexico; and girls in South Africa and New Zealand). In other countries, growing children overtook the height of their comparators (eg, Latvia, Czech Republic, Morocco, and Iran) or curbed their weight gain (eg, Italy, France, and Croatia) in late childhood and adolescence. When changes in both height and BMI were considered, girls in South Korea, Vietnam, Saudi Arabia, Turkey, and some central Asian countries (eg, Armenia and Azerbaijan), and boys in central and western Europe (eg, Portugal, Denmark, Poland, and Montenegro) had the healthiest changes in anthropometric status over the past 3·5 decades because, compared with children and adolescents in other countries, they had a much larger gain in height than they did in BMI. The unhealthiest changes—gaining too little height, too much weight for their height compared with children in other countries, or both—occurred in many countries in sub-Saharan Africa, New Zealand, and the USA for boys and girls; in Malaysia and some Pacific island nations for boys; and in Mexico for girls. Interpretation The height and BMI trajectories over age and time of school-aged children and adolescents are highly variable across countries, which indicates heterogeneous nutritional quality and lifelong health advantages and risks
Heterogeneous contributions of change in population distribution of body mass index to change in obesity and underweight NCD Risk Factor Collaboration (NCD-RisC)
From 1985 to 2016, the prevalence of underweight decreased, and that of obesity and severe obesity increased, in most regions, with significant variation in the magnitude of these changes across regions. We investigated how much change in mean body mass index (BMI) explains changes in the prevalence of underweight, obesity, and severe obesity in different regions using data from 2896 population-based studies with 187 million participants. Changes in the prevalence of underweight and total obesity, and to a lesser extent severe obesity, are largely driven by shifts in the distribution of BMI, with smaller contributions from changes in the shape of the distribution. In East and Southeast Asia and sub-Saharan Africa, the underweight tail of the BMI distribution was left behind as the distribution shifted. There is a need for policies that address all forms of malnutrition by making healthy foods accessible and affordable, while restricting unhealthy foods through fiscal and regulatory restrictions
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