1,220 research outputs found

    Application of chicken microarrays for gene expression analysis in other avian species

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    BACKGROUND: With the threat of emerging infectious diseases such as avian influenza, whose natural hosts are thought to be a variety of wild water birds including duck, we are armed with very few genomic resources to investigate large scale immunological gene expression studies in avian species. Multiple options exist for conducting large gene expression studies in chickens and in this study we explore the feasibility of using one of these tools to investigate gene expression in other avian species. RESULTS: In this study we utilised a whole genome long oligonucleotide chicken microarray to assess the utility of cross species hybridisation (CSH). We successfully hybridised a number of different avian species to this array, obtaining reliable signals. We were able to distinguish ducks that were infected with avian influenza from uninfected ducks using this microarray platform. In addition, we were able to detect known chicken immunological genes in all of the hybridised avian species. CONCLUSION: Cross species hybridisation using long oligonucleotide microarrays is a powerful tool to study the immune response in avian species with little available genomic information. The present study validated the use of the whole genome long oligonucleotide chicken microarray to investigate gene expression in a range of avian species

    VLT Diffraction Limited Imaging and Spectroscopy in the NIR: Weighing the black hole in Centaurus A with NACO

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    We present high spatial resolution near-infrared spectra and images of the nucleus of Centaurus A (NGC 5128) obtained with NAOS-CONICA at the VLT. The adaptive optics corrected data have a spatial resolution of 0.06" (FWHM) in K- and 0.11" in H-band, four times higher than previous studies. The observed gas motions suggest a kinematically hot disk which is orbiting a central object and is oriented nearly perpendicular to the nuclear jet. We model the central rotation and velocity dispersion curves of the [FeII] gas orbiting in the combined potential of the stellar mass and the (dominant) black hole. Our physically most plausible model, a dynamically hot and geometrically thin gas disk, yields a black hole mass of M_bh = (6.1 +0.6/-0.8) 10^7 M_sun. As the physical state of the gas is not well understood, we also consider two limiting cases: first a cold disk model, which completely neglects the velocity dispersion; it yields an M_bh estimate that is almost two times lower. The other extreme case is to model a spherical gas distribution in hydrostatic equilibrium through Jeans equation. Compared to the hot disk model the best-fit black hole mass increases by a factor of 1.5. This wide mass range spanned by the limiting cases shows how important the gas physics is even for high resolution data. Our overall best-fitting black hole mass is a factor of 2-4 lower than previous measurements. With our revised M_bh estimate, Cen A's offset from the M_bh-sigma relation is significantly reduced; it falls above this relation by a factor of ~2, which is close to the intrinsic scatter of this relation. (Abridged)Comment: 12 pages, 14 figures, including minor changes following the referee report; accepted for publication in The Astrophysical Journa

    Radiolysis of water ice in the outer solar system: Sputtering and trapping of radiation products

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    We performed quantitative laboratory radiolysis experiments on cubic water ice between 40 and 120 K, with 200 keV protons. We measured sputtering of atoms and molecules and the trapping of radiolytic molecular species. The experiments were done at fluences corresponding to exposure of the surface of the Jovian icy satellites to their radiation environment up to thousands of years. During irradiation, O2 molecules are ejected from the ice at a rate that grows roughly exponentially with temperature; this behavior is the main reason for the temperature dependence of the total sputtering yield. O2 trapped in the ice is thermally released from the ice upon warming; the desorbed flux starts at the irradiation temperature and increases strongly above 120 K. Several peaks in the desorption spectrum, which depend on irradiation temperature, point to a complex distribution of trapping sites in the ice matrix. The yield of O2 produced by the 200 keV protons and trapped in the ice is more than 2 orders of magnitude smaller than used in recent models of Ganymede. We also found small amounts of trapped H2O2 that desorb readily above 160 K.Fil: Bahr, D.A.. University of Virginia; Estados UnidosFil: Famá, M.. University of Virginia; Estados UnidosFil: Vidal, Ricardo Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Baragiola, Raul Antonio. University of Virginia; Estados Unido

    Расчет ГИН по схеме Аркадьева-Маркса

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    Объектом исследования является генератор импульсного напряжения по схеме Аркадьева-Маркса. Цель работы: спроектировать и рассчитать генератор импульсных напряжений. В процессе работы рассчитаны количественные значения элементов ГИНа: значения коэффициентов использования разрядной схемы и волны; емкость и индуктивность конденсатора; количество ступеней; фронтовое и разрядное сопротивления. Был выполнен расчет ресурсов, ставки налогов, отчислений. Так же было описаны рабочее место и законодательные и нормативные документы.The object of study is the generator of pulse voltage according to the scheme Arkadiev-Marx. Objective: to design and calculate the voltage impulse generator. In the process, the calculated quantitative values of the elements of a Hin: the coefficients of use of the discharge circuit and wave; the capacitance and inductance of the capacitor; number of steps; the front and discharge resistors. Calculated resources, tax rates, deductions. As described workplace and legislative and regulatory documents

    The Forest Economy of Haines, Alaska

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    The Institute of Social, Economic and Government Research of the University of Alaska carries on a series of study programs supporting the development of the state's natural resources. One such program is directed at improving the utilization of Alaska's valuable forest resource, the role by Alaska's timber industry. A Survey of the Alaskan Products Industry, published in 1966, provided a review and analysis of the growth and development of the pulp and lumber industry. Marketing Hardwoods from Alaska's Susitna Valley (1966) was the first in the Institute's study series on "Marketing Alaska's Timber Products" and focused attention on utilization in a particular geographic area, with emphasis on investigation of markets and marketing procedures. This report completes Phase II of the Institute's marketing series. It examines the timber resources and current utilization activity of the Haines area and utilizes the potential for pulp chip production. Other possible manufacturing alternatives are also investigated. Particular attention is paid to the role of the forestry sector in the community's economy. Phase III of the "Marketing Alaska's Timber Products" series is entitled "Analysis of Integrated Forest Utilization in the Railbelt Area of Alaska." The study, currently underway, is evaluating alternative methods of integrated utilization of forest land and timber in the railbelt area. Dr. Michael R. C. Massie has primary responsibility for the Institute's forestry research program. He was assisted in this study by Dr. Robert C. Haring, Head of the University of Alaska's Department of Business Administration. The study was financed by McIntire-Stennis cooperative forestry research i monies and State of Alaska matching funds, with additional support for this project from the Institute of Northern Forestry, Forest Service, U.S. Department of Agriculture. The analyses, conclusions, and recommendations of this report were reviewed by professionals and technical specialists in industry, government, and university research; their criticisms and helpful suggestions were most helpful and thoroughly appreciated. It is recognized that some of the issues dealt with are somewhat controversial and that not everyone may be fully satisfied by the findings of the authors. The purpose of the study has been to take a comprehensive and objective look at forest utili zation in one area of the state, and any disagreements engendered are likely to result from differing opinions and points of view. In any case, the important consideration must be the extent to which a report such as this contributes to better understanding and future progress. It is our belief that on these counts the Haines study makes a major contribution to more effective utilization of Alaska's forest resources.The State of Alask

    Resilience to loss and chronic grief: A prospective study from preloss to 18-months postloss

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    The vast majority of bereavement research is conducted after a loss has occurred. Thus, knowledge of the divergent trajectories of grieving or their antecedent predictors is lacking. This study gathered prospective data on 205 individuals several years prior to the death of their spouse and at 6- and 18-months postloss. Five core bereavement patterns were identified: common grief, chronic grief, chronic depression, improvement during bereavement, and resilience. Common grief was relatively infrequent, and the resilient pattern most frequent. The authors tested key hypotheses in the literature pertaining to chronic grief and resilience by identifying the preloss predictors of each pattern. Chronic grief was associated with preloss dependency and resilience with preloss acceptance of death and belief in a just world. The death of a spouse is generally assumed to be one of the most stressful experiences that people encounter during the course of their lives (Holmes & Rahe, 1967). However, there are marked individual differences in how much and for how long people grieve (Bonanno & Kaltman, 1999, 2001; Wortman & Silver, 1989, 2001). In addition to what is assumed to be the typical or common reaction, an initial increase in depression that gradually subsides over time, several other patterns of grief have been discussed in the literature. These include prolonged or chronic grieving, the noticeable absence of grief symptoms, and delayed grief responses. Social and personality psychologists have become increasingly interested in these different trajectories, and how they compare with those observed for other marital transitions and othe

    The influence of executive capacity on selective attention and subsequent processing

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    Recent investigations that suggest selective attention (SA) is dependent on top-down control mechanisms lead to the expectation that individuals with high executive capacity (EC) would exhibit more robust neural indices of SA. This prediction was tested by using event-related potentials (ERPs) to examine differences in markers of information processing across 25 subjects divided into two groups based on high vs. average EC, as defined by neuropsychological test scores. Subjects performed an experimental task requiring SA to a specified color. In contrast to expectation, individuals with high and average EC did not differ in the size of ERP indices of SA: the anterior Selection Positivity (SP) and posterior Selection Negativity (SN). However, there were substantial differences between groups in markers of subsequent processing, including the anterior N2 (a measure of attentional control) and the P3a (an index of the orienting of attention). EC predicted speed of processing at both early and late attentional stages. Individuals with lower EC exhibited prolonged SN, P3a, and P3b latencies. However, the delays in carrying out SA operations did not account for subsequent delays in decision making, or explain excessive orienting and reduced attentional control mechanisms in response to stimuli that should have been ignored. SN latency, P3 latency, and the size of the anterior N2 made independent contributions to the variance of EC. In summary, our findings suggest that current views regarding the relationship between top-down control mechanisms and SA may need refinement
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