NEAR's flyby of 253 mathilde: images of a C asteroid

On 27 June 1997, the Near Earth Asteroid Rendezvous (NEAR) spacecraft flew within 1212 kilometers of asteroid 253 Mathilde. Mathilde is an irregular, heavily cratered body measuring 66 kilometers by 48 kilometers by 46 kilometers. The asteroid's surface is dark (estimated albedo between 0.035 and 0.050) and similar in color to some CM carbonaceous chondrites. No albedo or color variations were detected. The volume derived from the images and the mass from Doppler tracking of the spacecraft yield a mean density of 1.3 +/- 0.2 grams per cubic centimeter, about half that of CM chondrites, indicating a porous interior structure.     

野生龙葵果中营养成分的研究

本研究对野生龙葵果营养成分进行了比较全面地分析测试，对矿物质及维生素含量进行分析的基础上，对野生龙葵果的其它营养成分进行了分析，并与一些常用果蔬进行了对比研究。结果表明，野生龙葵果含有丰富的营养成分。     

云南农业大学信息服务与用户调查研究分析

 通过对云南农业大学的教师、研究生和本科生的信息需求调查,了解到各类用户利用文献信息的状况和对文献信息的需求,为图书馆开展信息服务提供了依据。     

烤烟新品种南江3号在贵州烟区的生态适应性研究

以K326为对照,研究了烤烟新品种南江3号在贵州五大具有生态代表性烟区的农艺性状、生育期性状、抗病特征、经济性状、外观质量及吸食品质等指标。结果表明:与K326相比,南江3号在贵州烟区长势强、生育期长、抗病力强、产量和产值高、烟叶外观质量好,吸食品质与K326相当,在贵州烟区具有很好的生态适应性。     

Bird habitat preferences drive hemoparasite infection in the Neotropical region

The role that the environment plays in vector-borne parasite infection is one of the central factors for understanding disease dynamics. We assessed how Neotropical bird foraging strata and habitat preferences determine infection by parasites of the genera Haemoproteus, Plasmodium, Leucocytozoon, and Trypanosoma and filarioids, and tested for phylogenetic signal in these host–parasite associations. We performed extensive searches of the scientific literature and created a database of hemoparasite surveys. We collected data on host body mass, foraging strata, habitat preference, and migratory status, and tested if host ecological traits predict each hemoparasite occurrence and prevalence using a phylogenetic Bayesian framework. Species of Plasmodium tend to infect birds from tropical forests while birds from altitudinal environments are likely to be infected by species of Leucocytozoon. The probability of a bird being infected by filarioid or Trypanosoma is higher in lowland forests. Bird species that occur in anthropic environments and dry habitats of tropical latitudes are more susceptible to infection by species of Haemoproteus. Host foraging strata is also influential and bird species that forage in the mid-high and canopy strata are more prone to infection by species of Haemoproteus and filarioids. We also identified phylogenetic signal for host–parasite associations with the probability of infection of Neotropical birds by any hemoparasite being more similar among more closely related species. We provided a useful framework to identify environments that correlate with hemoparasite infection, which is also helpful for detecting areas with potential suitability for hemoparasite infection due to land conversion and climate change.     

Changes in the Chemistry of Precipitation in the United States, 1981–1998

Regulatory measures in the United States, such as Title IV of the Clean Air Act Amendments of 1990, have primarily restricted sulfur dioxide emissions as a way to control acidic deposition. These restrictions, coupled with increasing concentrations of NH₄ ⁺ in wet deposition in some regions of the U.S. and continued high emissions of nitrogen oxides have generated a significant shift in the chemistry of precipitation as measured at National Atmospheric Deposition Program/National Trends Network sites. Trends in precipitation chemistry at NADP/NTN sites were evaluated for statistical significance for the period 1981–1998 using a Seasonal Mann-Kendall Test, a robust non-parametric test for detection of monotonic trends. SO₄ ^2? declines were detected at 100 of the 147 sites examined while no sites exhibited increasing SO₄ ^2? trends. On average, SO₄ ^2? declined 35% over the period 1981–1998 with downward SO₄ ^2? trends being most pronounced in the north-eastern United States. In contrast, no consistent trends in NO₃ ^? concentrations were observed in precipitation in any major region of the United States. Although the majority of sites did not exhibit significant trends in NH₄ ⁺ concentration, 30 sites exhibited upward trends. For Ca²⁺ concentration in precipitation, 64 sites exhibited a significant decreasing trend and no sites exhibited an upward trend.     

Field comparison of the interferon-gamma assay and the intradermal tuberculin test for the diagnosis of bovine tuberculosis

An extensive field comparison of the gamma interferon (IFN-gamma) assay and the single intradermal tuberculin test for the diagnosis of bovine tuberculosis was conducted in Australia. The specificity of the IFN-gamma assay was determined by testing more than 6000 cattle from tuberculosis-free herds and varied from 96.2% to 98.1%, depending on the cut-off point chosen to define a positive reactor. For the sensitivity trial, cattle from herds being de-populated because of bovine tuberculosis were examined with both assays. The sensitivity of the IFN-gamma assay was shown to be significantly higher than the single intradermal tuberculin test and varied from 76.8% to 93.6% depending on the method of interpretation. A maximum overall sensitivity of 95.2% was obtained by testing with the IFN-gamma and the tuberculin test in parallel. The superior sensitivity of the IFN-gamma assay and the ability to adjust the sensitivity of the system depending on the task involved, will provide the Australian Tuberculosis Eradication Campaign with a valuable additional test to enable it to accomplish its goals.