Pathogenicity of H5N1 influenza A viruses isolated in Vietnam between late 2003 and 2005

Since late 2003, highly pathogenic H5N1 influenza A viruses have spread among poultry and wild aquatic birds in Asian countries. Transmission of these viruses to humans can be lethal. Most human cases of infection with H5N1 viruses have occurred in Vietnam. Therefore, to understand the pathogenicity in mammals of these H5N1 viruses, we took viruses isolated from poultry (5 strains) and humans (2 strains) in Vietnam and tested their virulence in mice. The results showed that the H5N1 viruses from humans were pathogenic in mice and that one avian isolate was also pathogenic. These findings suggested that the H5N1 viruses circulating in poultry adapted during replication in humans or that strains pathogenic in mice were transmitted directly to humans.     

Molecular characterization of the hemagglutinin and neuraminidase genes of H5N1 influenza A viruses isolated from poultry in Vietnam from 2004 to 2005

Highly pathogenic H5N1 avian influenza A viruses have been spreading among domestic poultry, wild aquatic birds, and humans in many Asian countries since 2003. The largest number of patients, to date, infected with the H5N1 viruses are in Vietnam, where these viruses continue to cause outbreaks in domestic poultry. Here, we molecularly characterized the hemagglutinin and neuraminidase genes of nine H5N1 viruses isolated between January 2004 and August 2005 from domestic poultry in Vietnam. We found that several groups of highly pathogenic H5N1 avian influenza viruses are circulating among these birds, which suggests that H5N1 viruses of different lineages have been introduced into Vietnam multiple times.     

Spatial optimization procedure for land-use arrangement in a community based on a human comfort perspective

The arrangement of land use substantially affects outdoor human comfort. The purposes of this study were to develop a spatial optimization procedure that involves combining simulated annealing algorithm with a microclimate model (ENVI-met) and to identify the relationship between the spatial pattern of the major cooling source and human comfort. The procedure is an assessment tool for appropriately designing living space on a community scale. The physiological equivalent temperature (PET) was used as the index of human comfort, and the objective of optimization was to minimize the difference in the PET to 23 °C within the study area. Four types of land use, namely buildings, paddies, parks, and ponds, were considered. Given the types of land use and the land areas, the procedure is used to determine the optimal layout that provides the most comfortable environment. The results revealed that the optimal design effectively improved the homogeneity of human comfort quantitatively and spatially in summer. Human comfort in the entire area was improved when the prevailing wind first passes through cooling sources, such as the paddies, and the walkways are easier to cool when the cooling sources are located nearby. The results of the spatial optimization procedure can further be applied to determine the relationship between the spatial pattern of land use and human comfort, and the relationship can be used as a reference for future research on community design.     

Evaluation of Soil Organic Matter Content under Topographic Influences in Agroforestry Ecosystems: a Study in Central Vietnam

Eurasian Soil Science - We investigate the key predictors that influence the soil organic matter (SOM) content in higher altitude plantations. This is to study the potential of carbon sequestration...     

Observation and Measurement of Residual Bran on Milled Rice Using Hyperspectral Imaging

Residual bran on milled rice is directly related to its quality. This study proposes a method to measure the residual bran patterns on a single rice grain by using hyperspectral imaging (HSI). HSI is a sensing technique that combines both spatial and spectral information and may be used for chemical compound identification and quantification. In this study, HSI was applied to assess rice bran residue nondestructively. In the experiment, rice samples were milled and scanned with an HSI system. Afterward, the rice samples were dyed to enable the residual bran to be identified with optical microscopy and image processing algorithms. Classifiers were then developed to predict the rice bran residue by using the HSI measurements as inputs. The predicted images were compared with the micrograph images for classifier performance evaluation. The proposed approach can estimate the residual bran distribution on milled rice surface with an accuracy of 93.5%.     

Atrazine residues in estuarine water and the aerial deposition of atrazine into Rhode River,Maryland

Water samples from the Rhode River, an estuary situated on the western shore of the Chesapeake Bay, were analyzed for atrazine residues twice a week for 2 yr. Precipitation samples; which included dryfall, rainfall, and snowfall were collected with wide-mouth stainless steel collection pans situated about 20 m above ground in an open space. A total of 68 precipitation samples was collected from December 1976 to February 1979. Atrazine residues were detectable in estuarine water and in rainwater year-round. Atrazine residues in estuarine water were generally 6 to 190 ng 1^?1 atrazine residues in rainwater (bulk precipitation) were 3 to 2190 ng 1^?1. Atrazine residues in rainwater samples collected during the winter season (January to April 1977) were unexpectedly high (e.g., 3 to 970 ng 1^?1). The highest atrazine concentration of 2190 ng 1^?1 was detected from a 0.76 cm rainfall event collected on May 19, 1977. Intermittent spraying operations of atrazine within the cornfields were generally done during May of each year. Rain samples collected during May of 1978 also showed higher atrazine residues than the rest of the 1978 growing season, but at levels much less than those detected in 1977 rainwater. Although high atrazine concentrations were detected in winter rainfall, these did not result in similarly higher atrazine concentrations in estuarine receiving waters. Our data showed a decline of atrazine concentrations in estuarine water in October and November which continued until a rainfall following Spring herbicide applications. Atrazine is enriched at the microsurface layer of estuarine water, but direct atmospheric input of atrazine did not seem to contribute significantly to the enrichment mechanism. Atrazine is believed to be transported long distances in polluted air masses. The estuarine microsurface layer could be a source of atmospheric atrazine, but the importance of the source is yet to be determined. Atrazine was quantitatively determined by GC using a nitrogen specific electrolytic detector and was confirmed by GC/Mass.     

山东省临沂地区杨树人工林地位指数表的编制

山东省临沂地区杨树人工林地位指数表是于1986年冬至1987年春,收集了25株69杨、72杨和健杨优势木树干解析和104块临时标地材料编制而成。选用lgH=a+b(1/A)公式为导向曲线数学模型;标准年龄定为8a;指数级距2m;级数8个(12—26m)。采用树高相对值法导出各指数级各年龄树高值,经检验此法精度较高,符合生长快、伐期短的杨树生长规律,可供该地区林业部门试用。