Morphological variation of the skull was examined in the northern treeshrew (Tupaia belangeri) from various localities across Southeast Asia. Through a multivariate analysis, the treeshrews from South Vietnam exhibited distinct morphological characteristics compared to other populations from Thailand and Laos, and Malaysia. The plots of the specimens of North Vietnam are not randomly mixed with Thailand plots segregation in the scatteregrams of canonical discriminant analysis. Since the skulls of the population from North Vietnam were morphologically similar to those form central Laos and northern and northeastern Thailand, the zoogeographical barrier effect of Mekong River was not clearly confirmed. The population of the Kanchanaburi in western Thailand is clearly smaller in size compared to the other populations. The southern border of the distribution of this species is determined by the Isthmus of Kra or Kangar-Pattani Line. In the northern treeshrew, which is distributed from southern China to Bangladesh and southern Thailand, we have detected osteometrical geographical variation driven by geography. These results indicate that the skull morphology in the Tupaia glis-belangeri complex distinctively differs in South Vietnam, western Thailand, and southern Thailand. The zoogeographical barrier and factor separating these districts are expected to clarify in the future. 相似文献
Paddy and Water Environment - In the Northern Vietnamese Mountains, paddy fields are the main source of foods and an important indicator to define wealth in ethnic communities. This paper deals... 相似文献
Fineroots (≤ 2 mm diameter) are dynamic components of the forest ecosystems and play important role in water and nutrient acquisition in forests. These roots are sensitive to forest fertilization and therefore, the response of fineroots to nutrient application would provide better understanding of the forest carbon and nutrient dynamics that will be helpful in sustainable forest management plans. Two fertilization treatments, including (1) F400: 400 g P2O5 (16.5%)/tree and (2) F600: 600 g P2O5 /tree, and F0: control (without fertilization), were applied in an Acacia mangium plantation with a planting density of 1100 trees/ha (3 m?×?3 m). The evaluation of fineroot growth across seasons showed that fertilization significantly increased production and subsequent mortality and decomposition. The total decomposition associated with F600 application was 7.95 tons ha?1 year?1, equaling 121% of F400 and 160% of the control. Mortality in F600 was 8.75 tons ha?1 year?1, equaling 111% of F400 and 198% of F0, while production in F600 was 10.40 tons ha?1 year?1, equaling 127% of F400 and 143% of F0. Fineroot production, mortality, and decomposition are seasonally dependent, with higher values measured in the rainy season than in the dry season. Stand basal area increment was significantly correlated with fineroot production (R2?=?0.75), mortality (R2?=?0.44), and decomposition (R2?=?0.48). This study showed that fertilization could facilitate fineroot production, which can then lead to a higher turnover of carbon and nutrients through the decomposition of the greater mass of the fineroots.
An unique procedure for the mass shoot propagation of Gerbera using receptacle transverse thin cell layer (tTCL) culture procedure was developed. Genotype, flower bud age, explant size, position of receptacle tTCLs and culture media were found to affect the success of culture. Ten interspecific crosses of Gerbera showed different shoot regeneration rates and callus induction via receptacle tTCL culture, all of which had shoot regeneration rates higher than 57%. Flower buds collected on the 10th day resulted in 91% shoot regeneration after 6 weeks of culture on basal MS medium [Murashige, T., Skoog, F., 1962. A revised medium for rapid growth and bioassay with tobacco tissue cultures. Physiol. Plant. 15, 475–497] supplemented with 0.02 mg l−1 thidiazuron (TDZ), 0.8 mg l−1 adenine and 10% (v/v) coconut water (CW). This was significantly higher than those from flower buds on the 7th and 14th days (22% and 54%), respectively. Shoot regeneration rate was the highest (94–100%) in the middle layers of the receptacle. For mass shoot propagation, shoot clusters were subcultured on half-strength MS medium supplemented with 0.5 mg l−1 indole-3-butyric acid (IBA), 0.5 mg l−1 6-benzyladenine (BA) and 2.0 mg l−1 kinetin after every 4 weeks. Plantlets formed when single shoots were cultured on half-strength MS medium containing 1 mg l−1 IBA. All plantlets acclimatized well in the greenhouse. 相似文献
Village communities are not homogeneous entities but a combination of complex networks of social relationships. Many factors such as ethnicity, gender, socio-economic status, and power relations determine one’s access to information and resources. Development workers’ inadequate understanding of local social networks, norms, and power relations may further the interests of better-off farmers and marginalize the poor. This paper explores how social networks function as assets for individuals and households in the rural areas of developing countries and influence access to information and benefits from research and development. A case study of such networks in Phieng Lieng village, in the northern mountains of Vietnam, provides evidence for the need for the efficient delivery of extension services and research and development interventions at the micro level.
Lan Anh Hoangis a social scientist with a special interest in social networks and gender and power relations in rural areas. She is currently working on her PhD at the School of Development Studies, University of East Anglia (UK) on “Gender relations, household power hierarchies, and social norms in migration decision-making in rural Vietnam.” She was involved in the Mountain Agrarian Systems Program in Bac Kan Province from 1999 to 2002.Jean-Christophe Castellais a production systems agronomist from the Institut de Recherche pour le Développement (IRD, France). Between 1998 and 2003, he coordinated a joint research program on “comprehensive study of land use changes in northern Vietnam uplands” in partnership with the Vietnam Agricultural Science Institute (VASI, Hanoi, Vietnam) and the International Rice Research Institute (IRRI, Philippines).Paul Novosadwas involved with the Mountain Agrarian Systems program from January to July 2002. He helped to synthesize the results of field research and also was involved in analyzing data related to social networks. Since fall 2002 he studies Public Administration and International Development at the Kennedy School of Government in the United States (Cambridge, Massachusetts).相似文献
A 34‐day‐old, male, white‐bellied caique (Pionites leucogaster) was presented for a complaint of bilateral buphthalmos. Clinical examination was unremarkable apart from the ophthalmic findings. The ophthalmologic examination was negative for direct, consensual, and dazzle reflexes in both eyes. The intraocular pressure exceeded 40 mm Hg OU. Fluorescein stain demonstrated corneal surface lesions suggestive of exposure keratopathy subsequent to bilateral buphthalmos. Diagnostic imaging tests were conducted to perform ocular biometric measurements and investigate the intraocular structures, including the iridocorneal angle and lens, by means of high‐resolution ultrasonography (HRUS). The presence of congenital glaucoma in this young parrot was strongly suspected after clinical and ophthalmological examination and the results of diagnostic imaging. Pharmacological treatment to reduce intraocular pressure was initiated using dorzolamide hydrochloride 2% and timolol maleate 0.5%. A month later, the parrot's eyes did not show any visual improvement, but the intraocular pressure had returned to normal. The parrot was unable to feed itself and died during a feeding procedure. Postmortem examination revealed ab ingestis pneumonia. Both eyes were submitted for histopathology, with severe anterior segment dysplasia and goniodysgenesis found OU. Histological findings added to the clinical presentation, the ophthalmologic examination and the imaging findings, confirmed the presence of congenital glaucoma. 相似文献
This study was conducted in 20 reservoirs, ranging in size from 4 to 30 ha, in the mountainous, northern region of Vietnam, in ThaiNguyen and YenBai provinces, over two growth cycles in 2002/03 and 2003/04. The reservoirs are leased by farmers for fishery activities from the provincial administration, and the trials were managed by the lessee farmers. Three species combinations in ratios (by fingerling weight) of grass carp: silver carp: bighead carp: common carp: mrigal 1:2:1:1:3 (A), 1:3:1:1:2 (B) and 1:2:1:1:2 (C) were used as seed stock. The overall mean yield of stocked fish in 2002/03 and 2003/04 growth cycles in reservoirs in ThaiNguyen and YenBai provinces was 165 (±21) and 190 (39), and 287 (±22) and 325 (±24) kg ha?1 respectively. The yield in reservoirs in both provinces, in both growth cycles and irrespective of the species combinations, increased in relation to stocking density. In reservoirs in ThaiNguyen Province, the species combination B gave the lowest yield (both growth cycles and overall), and differed significantly (P<0.05) from combinations A and C. The stocking efficiency (ratio of the yield of stocked fish in kg ha?1 to the weight of the stocked fish in kg ha?1) in reservoirs in ThaiNguyen Province ranged from 2.9 to 5.1 over the two growth cycles and that in YenBai from 2.8 to 3.9. There was no discernible trend between growth cycles and/or between species combinations. The major cost incurred was for fingerling procurement. In all instances, a net profit was accrued. The mean (±standard error (SE)) net profit ha?1 (in 103VN dong; approximately 15 500 VND=1 US$) was 885 (±270) and 864 (±214), and 1322 (±176) and 1600 (±150) for the growth cycles 2002/03 and 2003/04 for reservoirs in ThaiNguyen and YenBai provinces respectively. Between the two growth cycles, the net profit increased in eight and three reservoirs from YenBai and ThaiNguyen, respectively, the maximum increase being recorded in Khuan Gio (165%) and Dong Man (39%) reservoirs. 相似文献
Diseases in shrimp farms in the Mekong Delta of Vietnam cause significant crop losses and are therefore of great concern to producers. Once a pond becomes infected, it is difficult to prevent spread of the disease to nearby shrimp farming areas. Thus, predicting the occurrence of disease is an essential part of reducing the risk for shrimp farmers. In this study, we applied an integrated geographic information system and machine learning system to predict three serious diseases of shrimp, namely, acute hepatopancreatic necrosis, white spot syndrome disease, and Enterocytozoon hepatopenaei infection, based on data collected from shrimp farms in the Tra Vinh, Bac Lieu, Soc Trang, and Ca Mau provinces of Vietnam. We first constructed a map showing the distribution of these diseases using the locations of affected farms, and then we conducted spatial analysis to acquire the geographical features of the affected locations. This latter information was combined with environmental factors and clinical signs to form the set of independent variables affecting the outbreak of diseases. The neural network model outperformed the logistic regression, random forest, and gradient boosting methods in terms of predicting infection to estimate the probability of disease occurrence in farmed areas. Acute hepatopancreatic necrosis disease infected farms downstream of the Co Chien and Hau Rivers of Tra Vinh and west of Ca Mau. Enterocytozoon hepatopenaei infection is distributed in Soc Trang Province, while white spot syndrome virus has spread to the coastal districts of Soc Trang and Bac Lieu Provinces, where it is highly associated to water from a complex canal system.