University of Science Ho Chi Minh City

Ho Chi Minh City, Vietnam

University of Science Ho Chi Minh City

Ho Chi Minh City, Vietnam
SEARCH FILTERS
Time filter
Source Type

Khoi D.N.,Yamanashi University | Suetsugi T.,University of Science Ho Chi Minh City
Journal of Water and Climate Change | Year: 2012

The Be River Catchment was studied to quantify the potential impact of climate change on the streamflow using a multi-model ensemble approach. Climate change scenarios (A1B and B1) were developed from an ensemble of four GCMs (general circulation models) (CGCM3.1 (T63), CM2.0, CM2.1 and HadCM3) that showed good performance for the Be River Catchment through statistical evaluations between 15 GCM control simulations and the corresponding time series of observations at annual and monthly levels. The Soil and Water Assessment Tool (SWAT) was used to investigate the impact on streamflow under climate change scenarios. The model was calibrated and validated using daily streamflow records. The calibration and validation results indicated that the SWAT model was able to simulate the streamflow well, with Nash-Sutcliffe efficiency exceeding 0.78 for the Phuoc Long station and 0.65 for the Phuoc Hoa station, for both calibration and validation at daily and monthly steps. Their differences in simulating the streamflow under future climate scenarios were also investigated. The results indicate a 1.0-2.9 WC increase in annual temperature and a -4.0 to 0.7% change in annual precipitation corresponding to a change in streamflow of -6.0 to -0.4%. Large decreases in precipitation and runoff are observed in the dry season.© IWA Publishing 2012.


Stuart B.L.,North Carolina Museum of Natural science | Rowley J.J.L.,College Street | Tran D.T.A.,University of Bonn | Le U.T.T.,University of Science Ho Chi Minh City | Hoang H.D.,University of Science Ho Chi Minh City
Zootaxa | Year: 2011

We sampled two forms of Leptobrachium in syntopy at the type locality of L. pullum at upper elevations on the Langbian Plateau, southern Vietnam. The two forms differed in morphology (primarily in coloration), mitochondrial DNA, and male advertisement calls. One form closely agrees with the type series of L. pullum (but not to its original description due to error), and the other is described as new. Leptobrachium leucops sp. nov. is distinguished from its congeners by having small body size (males with SVL 38.8-45.2), the upper one-third to one-half of iris white, a blue scleral arc, a dark venter, and sexually active males without spines on the upper lip. Leptobrachium pullum and L. mouhoti, a recently described species from low-elevation slopes of the Langbian Plateau in eastern Cambodia, are morphologically divergent but genetically similar, warranting further investigation into geographic variation in the red-eyed Leptobrachium of southern Indochina. © 2011 Magnolia Press.


Khoi D.N.,Yamanashi University | Khoi D.N.,University of Science Ho Chi Minh City | Suetsugi T.,Yamanashi University
Water and Environment Journal | Year: 2012

This paper focuses on the uncertainty in climate change impacts on streamflow in Be River Catchment. Uncertainty associated with GCM structure from a subset of CMIP3 (CCCMA CGCM3.1, CSIRO Mk30, IPSL CM4, MPI ECHAM5, NCAR CCSM3.0, UKMO HadGEM1, and UKMO HadCM3), SRES emission scenarios (A1B, A2, B1, and B2), and prescribed increases in global mean temperature (0.5°C to 6°C) using SWAT model is investigated. For prescribed warming scenarios using HadCM3, linear decreases in mean annual streamflow range from 3.1 to 16.7%. Differences in projected annual streamflow between SRES emission scenarios using HadCM3 are small (-5.6% to -4.6%). Under the A1B scenario and 2°C increase in global mean temperature using seven GCMs, there is substantial disparity, by -2.9-25.5% and -8.3-19.1%, respectively. It is generally reasonable to conclude that GCM structure-related uncertainty is greater than that associated with the emission scenarios and climate sensitivity. © 2012 The Authors. Water and Environment Journal © 2012 CIWEM..


Rowley J.J.L.,College St | Le D.T.T.,University of Science Ho Chi Minh City | Hoang H.D.,University of Science Ho Chi Minh City | Dau V.Q.,Institute of Ecology and Biological Resources | Cao T.T.,Vinh University
Zootaxa | Year: 2011

Two new species of rhacophorid frogs in the genus Theloderma are described from high-elevation montane forest on the Kon Tum and Langbian Plateaus in Vietnam, on the basis of morphological and molecular evidence. Both new species are differentiated morphologically from their congeners by their small body size (<30 mm SVL); absence of vomerine teeth; rugose skin texture with minute, calcified dorsal asperities; no webbing on hands; brownish dorsum; and a bicoloured iris (pale gold in upper third and reddish brown in lower two-thirds). Molecular evidence supports that both new species are members of genus Theloderma, and are distinct from all congeners sampled (uncorrected sequence divergences at the 16S rRNA gene of >8.5% for all Theloderma for which homologous 16S rRNA sequences are available). The new species are differentiated from each other by dorsal pattern, extent of dorsal asperities, and by mitochondrial DNA. Copyright © 2011, Magnolia Press.


Rowley J.J.L.,College St | Rowley J.J.L.,James Cook University | Hoang H.D.,University of Science Ho Chi Minh City | Dau V.Q.,Institute of Ecology and Biological Resources | And 2 more authors.
Zootaxa | Year: 2012

We describe a new species of Leptolalax from central Vietnam. Leptolalax firthi sp. nov. is distinguished from its congeners by a combination of the following characters: an absence of distinct dark brown or black dorsolateral markings; toes with rudimentary webbing and wide lateral dermal fringes in males and weak or absent lateral dermal fringes in females; most males with wide lateral dermal fringes on Finger II; medium size (26.4-29.2 mm in 21 adult males, 25.7-36.9 mm in 14 females); and near immaculate white chest and belly. The male advertisement call of the new species, consisting of 2-5 notes with a dominant frequency of 5.4-6.6 kHz (at 18.3-21.2° C) is also unique among Leptolalax species for which calls are known. Uncorrected sequence divergences between L. firthi and all homologous 16S rRNA sequences available were >10%. At present, the new species is known from montane evergreen forest between ∼860-1720 m elevation in Kon Tum and Quang Nam Provinces. The extreme sexual dimorphism observed in L. firthi in terms of lateral dermal fringing, a morphological character often used to distinguish Leptolalax species, highlights the importance of ensuring interspecific comparisons in the genus are performed separately for each sex. Copyright © 2012 · Magnolia Press.


Nguyen T.H.,University of Science Ho Chi Minh City | Hoang D.,University of Science Ho Chi Minh City | Le L.,Ho Chi Minh City International University
IFMBE Proceedings | Year: 2013

M2 protein plays as an proton channel in influenza virus, and many candidates were proposed to inhibit its activity. Three new inhibitors were proposed recently by Du Q-S, et al. (2010), and their biding energy was higher than two commercial drug, Amantadine and Rimantadine. To investigate the potency of the new compound on drug-resistant variants, molecular docking was used to investigate how they bind in two positions of M2 proton channel and its mutants of H3N2 virus. The global docking on the M2 protein (residues 22-46) showed that the coexistence of two binding positions in NMR structure is possible, but the inhibitors favor the in pore position more than the outside of the pore. In the detail docking, mean binding energies of the new inhibitors were lower the commercial drugs, Rimantadine. The comparison between mean binding energy and intermolecular energy indicated that the torsional free energy has caused this decreasing energy. In another word, the adding new groups actually increase binding energy of inhibitors but it also makes them heavy and hard to rotate. In other hand, these new inhibitors were failed in binding on mutant D44A, and their binding energies were no different between wild type and mutants V27A, S31N and L26F. These mutants have suggested some hints to improve inhibitors' structure, and chosen a choice about how these mutants resist the inhibitors. © 2013 IFMBE.


Rowley J.J.L.,College St | Le D.T.T.,University of Science Ho Chi Minh City | Tran D.T.A.,University of Bonn | Hoang H.D.,University of Science Ho Chi Minh City
Zootaxa | Year: 2011

We describe a new species of small megophryid frog from the Langbian Plateau in southern Vietnam, the southernmost record of Leptolalax from Vietnam. Leptolalax bidoupensis sp. nov. is distinguished from its congeners by a combination of a dark brownish red ventral surface with white speckling on entire ventral surface including throat, arms and legs, small size (23.6-24.6 mm in four adult males and 29.2-29.4 mm in two adult females), bicoloured iris (coppery red upper half, fading to pale silver ventrally), a mostly smooth skin texture with no skin ridges, and relatively short tibia (male TIB:SVL 0.44-0.46). The male advertisement call of the new species, consisting of 6-9 single-pulsed notes with a dominant frequency of 1.9-3.8 kHz, is also unique among Leptolalax species for which calls are known. From the morphologically similar L. applebyi and L. melicus, L. bidoupensis sp. nov. differs by 9.3% and 9.6% sequence divergence at the 16S mtDNA gene. At present, the new species is known from montane evergreen forest between 1620-1730 m elevation, within an area of 1 km2. We suggest the species should be considered Data Deficient following IUCN's Red List categories. © 2011 Magnolia Press.


Rowley J.J.L.,College St | Tran D.T.A.,University of Bonn | Hoang H.D.,University of Science Ho Chi Minh City | Le D.T.T.,University of Science Ho Chi Minh City
Journal of Herpetology | Year: 2012

We describe a new species of Rhacophorus from lowland forests in southern Vietnam. The new species is most similar to Rhacophorus kio, but differs from this and all other Rhacophorus from Southeast Asia by a combination of its large body size (males 72.3-85.5 mm; females 89.4-90.7 mm snout-vent length); green dorsum; white venter; black patch at axilla; bluish-green posterior surface of thighs with pale yellow marbling; low, single-lobed supracoloacal dermal ridge, and white sclera. In contrast to the widely distributed R. kio, the new species is known only from two fragments of disturbed, low-elevation forest approximately 30 km apart in a highly modified agricultural landscape. The continued survival of the new species is threatened by ongoing habitat loss and degradation. © 2012 Society for the Study of Amphibians and Reptiles.


Le T.K.,University of Pau and Pays de l'Adour | Flahaut D.,University of Pau and Pays de l'Adour | Martinez H.,University of Pau and Pays de l'Adour | Pigot T.,University of Pau and Pays de l'Adour | And 2 more authors.
Applied Catalysis B: Environmental | Year: 2013

Fluorinated TiO2 was prepared from anatase and rutile monophasic TiO2 nanopowders by thermal shock method at different temperatures (400-950°C), then characterized by XRD, SEM, XPS in order to elucidate the influences of thermal shock fluorination on the crystallite structure, morphologies and surface structure of TiO2 in different phases. Their photocatalytic activities were evaluated via the degradation of methylene blue. According to the results, the fluorination below 600°C did not change the crystallite structure or the particle size. However, the surface hydroxyl groups content is increased with the creation of fluoride ions and oxygen/titanium vacancies on the surface of anatase/rutile TiO2 which are all involved in the improvement of the photocatalytic activity. The TiO2 anatase fluorinated at 500°C showed the best photocatalytic behaviour under UV light whereas the TiO2 rutile fluorinated at 500°C is the best photocatalyst under visible light. At higher thermal shock temperatures, the photocatalytic activity decreased, which was assigned to the decrease of the surface hydroxyl groups and vacancies content and the formation of the K2Ti6O13 phase. © 2013 Elsevier B.V.


Ly T.,University of Science Ho Chi Minh City | Hoang H.D.,University of Science Ho Chi Minh City | Stuart B.L.,North Carolina Museum of Natural science
Biological Conservation | Year: 2011

Asian turtles are overharvested for food, medicinal purposes and pets, and most species are now at risk of extinction ('Asian turtle crisis'). As a result of high levels of trade, some species of Asian turtles are known to science mostly or only from animals found in trade. The Vietnamese box turtle (Cuora picturata) was described in 1998 and is known only from markets. This species is likely to be highly threatened, and identifying the origin of this " market species" is imperative if it is to be conserved. We used evidence from phylogeny, biogeography and trade patterns to focus field searches for this species, and in July 2010-January 2011 found it in the wild at three localities on the Langbian Plateau of southern Vietnam. This discovery provides the first opportunity to conserve the Vietnamese box turtle, and provides hope for determining the wild origin of other rare Asian turtles that remain known only from commercial trade. © 2011 Elsevier Ltd.

Loading University of Science Ho Chi Minh City collaborators
Loading University of Science Ho Chi Minh City collaborators