106 research outputs found
AMMONIA REMOVAL FROM SWINE WASTEWATER USING AN AEROBIC, ANOXIC FILTER AT A PILOT-SCALE IN THANH LOC BIOSTATION
Joint Research on Environmental Science and Technology for the Eart
R-matrix method and the nonlocal nucleon optical potential
The calculable R-matrix method is applied to solve the Schr Ìodinger equationin the optical model (OM) analysis of the elastic nucleon-nucleus scatter-ing using a nonlocal nucleon optical potential (OP). The phenomenologicalnonlocal nucleon OP proposed by Perey and Buck (PB), and the two recentversions of the PB parametrization were used in the present OM study of theelastic nucleon scattering on 208 Pb and 27 Al targets at different energies. Thecomparison of the OM results given by the calculable R-matrix method withthose given by other methods confirms that the calculable R-matrix methodis an efficient tool for the OM study of the elastic nucleon-nucleus scatteringusing a nonlocal nucleon OP
Hygiene and microbial contamination along the pork value chain in Vietnam
In Vietnam, pork accounts for 75% of total meat consumed
daily at households. However, pork may contain high levels of
microbial contamination such as Salmonella and Escherichia coli
which might cause harm to consumers. To determine microbial
contamination along the pork value chain, we collected 216
samples from 72 pig farms (floor swab, drinking and waste
water), 545 from 49 slaughterhouses (carcass swab, lymph node,
rectal feces, floor swab and washing water) and 514 from 220
pork shops in the informal markets (pork cuts, ground pork and
cutting board swab) in two provinces of Vietnam (Hung Yen
and Nghe An). Samples were analyzed to detect qualitatively
and quantitatively Salmonella and E. coli. Overall prevalence of
Salmonella combined from all types of above mentioned samples
at pig farms, slaughterhouses and pork shops were 35%, 30%
and 37%, respectively. Salmonella contamination in the final
product (pork at market) was 45% and an average concentration
of 9 MPN/g was recorded. E. coli average load along different
points of the chain was 5.3 ± 1.4 (farm floor swabs), 2.9 ± 0.9
(carcass swabs), 3.1 ± 1.0 (slaughterhouse floor swabs), and
3.3 ± 1.1 (market shop cutting board swabs) logCFU/cm2,
whereas pork from the market had 3.4 ± 0.9 logCFU/g. Demonstrated
high levels of Salmonella in the final product (pork at
market) induces the potential health risks for the consumers.
High values for E. coli indicates general poor hygiene along the
chain. Appropriate hygiene practices and management are
required to achieve better pork quality and reduce the risk for
the consumer. These data will serve as inputs for health risk
assessments related to pork consumption
Design and fabrication of the trapezoidal electrostatic comb-drive actuator
This paper reports the design, fabrication and characterization process of the trapezoidal Electrostatic Comb-drive Actuator (ECA) with the slope angle α=20. Together with the trapezoidal ones, the rectangular ECA with identical dimension was also designed and fabricated for comparison purpose. In order to reduce calculating deviation, the fringing effect was also taken into consider while carrying out theoretical analysis. The obtained results pointed out the fact, that the trapezoidal ECA excels the rectangular ones with the same numbers of teeth in electrostatic force and displacement generation, while requires relatively low driving voltage. But it is also observed that with higher driving voltage (larger than 50V), the trapezoidal ECA starts to lose its stability (the lateral pull-in phenomenon occurs)
A community participatory intervention model to reduce the health risks from biogas wastewater in Hanam Province, Vietnam
In Vietnam, using biogas to treat livestock waste is common, in particular on small holder farms. However, most small holder farms do not know how to use biogas correctly and wastewater can affect health and the environment. Using a participatory approach with farmers and other stakeholders we developed and implemented a set of interventions in Hanam province to reduce health risks from biogas wastewater. Twenty-four pig farmers were selected as a "core group" to be instrumental in developing the interventions and training other farmers to correctly use biogas. The intervention model was piloted for 6 months. Several outputs were obtained including i) approval and enforcement of a "huong uoc - village law" on environmental protection; ii) training of 24 farmers from the core group in communication skills to share information on using biogas; iii) development of a 6-step program of pig cage cleaning to limit waste loaded to biogas to improve the efficiency of biogas production; iv) a health monitoring books for humans and animals for use by families in the community. The results provided evidence that applying the participatory approach can lead to improved knowledge and practices of farmer using biogas and can reduce the health risks from biogas wastewater
THE RELATIONSHIPS BETWEEN STUDENTSâ SELF-CONFIDENCE AND THEIR ENGLISH-SPEAKING PERFORMANCE: A CASE STUDY OF ENGLISH-MAJORED STUDENTS AT A PRIVATE UNIVERSITY IN VIETNAM
This research aimed to discover the relationships between students' self-confidence and their English-speaking performance. In our research, self-confidence was divided into three components which are affective confidence, behavioral confidence, and cognitive confidence. In addition, speaking performance included eight components which are vocabulary, grammar, pronunciation, fluency, coherence, comprehension, task, and content. A sample of 150 English-majored students at a university in Vietnam was surveyed in this study by using a convenience sampling technique, and then conducting semi-structured interviews to seek for qualitative information from 10 participants out of 150. The result from our study showed that there are significant relationships between the two variables. The more confident the students are, the more accomplished they would be in the presenting procedure since they have superior cognition and understand how to modify their learning methods to build a comprehensive individual in learning English language. We expect that these findings can help students adjust their learning methods to improve their self-confidence as well as English speaking performance and by that way, universities can add more speaking-related subjects so that students can have more opportunities to speak and learn more speaking skills. Article visualizations
ASSESSMENT OF GEOMORPHIC PROCESSES AND ACTIVE TECTONICS IN CON VOI MOUNTAIN RANGE AREA (NORTHERN VIETNAM) USING THE HYPSOMETRIC CURVE ANALYSIS METHOD
the Day Nui Con Voi (DNCV) area of Vietnam. For this purpose, a spatial database was collected and constructed, including DEM (Digital Elevation Model) and a geological map. The hypsometric curve (HC) analysis method and its statistical moments were adopted to use for the assessment. These methods have been widely used for the assessment of geomorphic processes and active tectonics in many areas in the world showing promising results. A total of 44 sub-basins of the Red River and the Chay river were analyzed. The result shows that 3 curve-types such as "straight- shape", "S- shape", and concave were found; with the concave curve being the dominant and widely distributed in the northeast side and in the south of the southwestern side of the study area. The hypsometric integral (HI) values are rather small with the largest value is 0.37 and the smallest one is 0.128. Other statistical moments of the hypsometric curve, i.e. skew (SK), kurtosis (KUR), and the density function (density skew - DSK and density kurtosis-DKUR) show great values, which increased in the south direction of the area study. Accordingly, recent active tectonics (uplift-lower) in the study area is generally weak; however, they are also not completely homogeneous and can be distinguished by different levels. The southwestern side is being lifted higher than the northeastern side. The northern part is being lifted larger than the southern part. In the region, the uplift activities were increased gradually in the Pliocene-Quaternary and could have stopped at certain time in the past. The current geomorphic processes are mainly headward erosion in the upstream.References Allen, C.R., Gillepie, A.R., Han, Y., Sieh, K.E., Zhu, C., 1984. 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Effect of Silica Nanoparticles on Properties of Coatings Based on Acrylic Emulsion Resin
Effect of nanosilica size on physic-mechanical properties, thermal stability and weathering durability of coating based on acrylic emulsion. Nanocomposite coating formulas were filled by 2 wt.% nanosilica particles which were used in this study, namely: nanosilica from Sigma (15-20nm), nansilica from rice husk (~70-200 nm) and nanosilica from Arosil â Belgium (7-12 nm). Obtained results showed that viscosity flow of coating formula containing nanosilica from Arosil saw the highest flow-time while coating formulas filled other nanosilica and unfilled nanosilica experienced similar flow-time. In presence of nanosilica, coating properties were improved in comparison with neat coating. However, coating filled by nanosilica from rice husk indicated the best properties in studied coating formula. It may explained that size of nanosilica from rice husk was the largest in studied nanosilica particles and thus easily dispersing into coating formula
Monitoring for Plasmodium falciparum drug resistance to artemisinin and artesunate in Binh Phuoc Province, Vietnam: 1998-2009
<p>Abstract</p> <p>Background</p> <p>Artemisinin derivatives have been used for malaria treatment in Vietnam since 1989. Reported malaria cases have decreased from 1,672,000 with 4,650 deaths in 1991, to 91,635 with 43 deaths in 2006. Current national guidelines recommend artemisinin-based combination therapy (ACT), although artesunate is still available as monotherapy through the private sector. Recent reports suggest that effectiveness of ACT and artesunate monotherapy has declined in western Cambodia. This study examined <it>Plasmodium falciparum </it>resistance patterns over 10 years in southwest Vietnam in infected patients treated with artemisinin compounds.</p> <p>Methods</p> <p>The study was conducted in two communes in Phuoc Long district, Binh Phuoc province, 100 km west of the Cambodian border. This was chosen as a likely site for emerging artemisinin resistance because of the high prevalence of <it>P. falciparum </it>malaria, and the length of time that artemisinin had been in use. In <it>vivo </it>and <it>in vitro </it>monitoring of <it>P. falciparum </it>susceptibility to anti-malarial drugs was conducted in 1998, 2001, 2004/5, and 2008/9. Patients with confirmed <it>P. falciparum </it>malaria received therapy with 5 or 7 days of artemisinin (1998 and 2001 respectively) or 7 days of artesunate</p> <p>Results</p> <p>In the four surveys, 270 patients were recruited and treated. The mean parasite clearance times differed between 1998, 2001 and 2004/5 (1.8, 2.3 and 2.1 days, P < 0.01) but not between 1998 and 2008/2009. The mean parasite clearance times were correlated with parasite density at day 0 (r = 0.4; P < 0.001). Treatment failure rates after PCR adjustment were 13.8%, 2.9%, 1.2%, and 0% respectively. Susceptibility of <it>P. falciparum </it>to artemisinin in <it>in vitro </it>tests was stable during the period, except for a rise in EC90 and EC99 in 2001.</p> <p>Conclusions</p> <p>This study showed stable levels of <it>P. falciparum </it>sensitivity to artemisinin compounds in the two sites over a ten-year period. The introduction of ACT in this area in 2003 may have protected against the development of artemisinin resistance. Adherence to the latest WHO and Vietnamese guidelines, which recommend ACT as first-line therapy in all malarious areas, and continued monitoring along the Vietnam-Cambodia border will be essential to prevent the spread of artemisinin resistance in Vietnam.</p
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