535 research outputs found

    Electronic Structure of Nearly Ferromagnetic compound HfZn2_{2}

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    The electronic structure of HfZn2_{2} has been studied based on the density functional theory within the local-density approximation. The calculation indicates that HfZn2_{2} shows ferromagnetic instability. Large enhancement of the static susceptibility over its non-interacting value is found due to a peak in the density of states at the Fermi level

    Basic Issues in Economic Comparisons of Commercial and Sport Fisheries: A Study of Allocation Alternatives for Alaska Kenai River Sockeye Salmon Fisheries

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    Allocation between commercial and sport fisheries is becoming an increasingly difficult and divisive issue in fisheries management. As conflicts over allocation have increased, so has interest in the relative economic contributions of commercial and sport fisheries. This paper describes eight basic issues in economic comparisons of commercial and sport fisheries. These basic issues should be considered in evaluating or planning any economic comparison of commercial and sport fisheries--from a back-of-the-envelope comparison to a formal study. We illustrate these issues by describing how they arose in an economic comparison o f commercial and sport fisheries for Alaska's Kenai River sockeye salmon. Prepared for presentation at a session on "The Role of Economics in Fisheries Management" at the 1998 Annual Meeting of the American Fisheries Society Hartford, Connecticut August 24, 199

    Abnormal distribution of CD8 subpopulation in B-chronic lymphocytic leukemia identified by flow cytometry

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    We studied the occurrence of T-cell subpopulations for patients with B-cell chronic lymphocytic leukemia. The CD8+ population was divided into CD8+ suppressor (CD8a+) and CD8+ cytotoxic (CD8b+) lymphocytes using difference in orthogonal light scattering.\ud \ud Average CD4+/CD8+ratios determined for all patients were decreased. For individual patients this sometimes was not true. In contrast CD4+/CD8a+ ratios were markedly increased in all individual patients. The CD8+ lymphocytes appeared to consist mainly of CD8b+lymphocytes. Moreover the CD8b+/CD8+ ratio correlated with clinical stage: untreated patients (stage 0 of Rai) have smaller CD8b+/CD8+ ratios than patients with advanced stages of Rai

    Psychological factors associated with uptake of the childhood influenza vaccine and perception of post-vaccination side-effects : a cross-sectional survey in England

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    Objectives To identify predictors of: uptake of the childhood influenza vaccine in the 2015–2016 influenza season, parental perceptions of side-effects from the influenza vaccine and intention to vaccinate one's child for influenza in the 2016–2017 influenza season. Design Cross-sectional online survey. Setting Data were collected in England shortly after the end of the 2015–2016 immunization campaign. Participants 1001 parents or guardians of children aged between two and seven. Main outcome measures Self-reported uptake of the childhood influenza vaccine in the 2015–2016 influenza season, perception of side-effects from the influenza vaccine and intention to vaccinate one's child in the 2016–2017 influenza season. Results Self-reported uptake of the childhood influenza vaccine was 52.8%. Factors strongly positively associated with uptake included the child having previously been vaccinated against influenza, perceiving the vaccine to be effective and perceiving the child to be susceptible to flu. Factors strongly negatively associated with uptake included perceiving the vaccine to be unsafe, to cause short-term side-effects or long-term health problems and believing that yearly vaccination may overload the immune system. Predictors of intended vaccine uptake in 2016–2017 were similar. Participants who perceived side-effects after the 2015–2016 vaccination reported being less likely to vaccinate their child next year. Side-effects were more likely to be reported in first-born children, by participants who knew another child who had side-effects, those who thought that the vaccine would interact with medication that the child was currently taking, and those who believed the vaccine causes short-term side-effects. Conclusions Perceptions about the childhood influenza vaccine show strong associations with uptake, intended uptake and perception of side-effects. Attempts to improve uptake rates from their current low levels must address these perceptions

    Development of a dynamic energy-partitioning model for enteric methane emissions and milk production in goats using energy balance data from indirect calorimetry studies

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    [EN] The main objective of this study was to develop a dynamic energy balance model for dairy goats to describe and quantify energy partitioning between energy used for work (milk) and that lost to the environment. Increasing worldwide concerns regarding livestock contribution to global warming underscore the importance of improving energy efficiency utilization in dairy goats by reducing energy losses in feces, urine and methane (CH4). A dynamic model of CH(4)emissions from experimental energy balance data in goats is proposed and parameterized (n= 48 individual animal observations). The model includes DM intake, NDF and lipid content of the diet as explanatory variables for CH(4)emissions. An additional data set (n= 122 individual animals) from eight energy balance experiments was used to evaluate the model. The model adequately (root MS prediction error,RMSPE) represented energy in milk (E-milk;RMSPE = 5.6%), heat production (HP;RMSPE = 4.3%) and CH(4)emissions (E-CH4; RMSPE = 11.9%). Residual analysis indicated that most of the prediction errors were due to unexplained variations with small mean and slope bias. Some mean bias was detected for HP (1.12%) and E-CH4(1.27%) but was around zero for E-milk (0.14%). The slope bias was zero for HP (0.01%) and close to zero for E-milk (0.10%) and E-CH4(0.22%). Random bias was >98% for E-CH4, HP and E-milk, indicating non-systematic errors and that mechanisms in the model are properly represented. As predicted energy increased, the model tended to underpredict E-CH(4)and E-milk. The model is a first step toward a mechanistic description of nutrient use by goats and is useful as a research tool for investigating energy partitioning during lactation. The model described in this study could be used as a tool for making enteric CH(4)emission inventories for goats.This study was supported by LOW CARBON FEED Project reference LIFE2016/CCM/ES/000088.Fernández Martínez, CJ.; Hernando, I.; Moreno-Latorre, E.; Loor, J. (2020). Development of a dynamic energy-partitioning model for enteric methane emissions and milk production in goats using energy balance data from indirect calorimetry studies. Animal. 14:s382-s395. https://doi.org/10.1017/S1751731120001470Ss382s39514Agricultural and Food Research Council (AFRC) 1997. The nutrition of goats. Nutrition Abstract and Reviews (Series B) 67, 776–861.Aguilera, J. F., Prieto, C., & FonollÁ, J. (1990). Protein and energy metabolism of lactating Granadina goats. British Journal of Nutrition, 63(2), 165-175. doi:10.1079/bjn19900104Bannink, A., France, J., Lopez, S., Gerrits, W. J. J., Kebreab, E., Tamminga, S., & Dijkstra, J. (2008). 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KL Blaxter ), pp. 441–443. Academic Press, London, UK.Criscioni, P., Marti, J. V., Pérez-Baena, I., Palomares, J. L., Larsen, T., & Fernández, C. (2016). Replacement of alfalfa hay ( Medicago sativa ) with maralfalfa hay ( Pennisetum sp.) in diets of lactating dairy goats. Animal Feed Science and Technology, 219, 1-12. doi:10.1016/j.anifeedsci.2016.05.020Ellis, J. L., Kebreab, E., Odongo, N. E., McBride, B. W., Okine, E. K., & France, J. (2007). Prediction of Methane Production from Dairy and Beef Cattle. Journal of Dairy Science, 90(7), 3456-3466. doi:10.3168/jds.2006-675Statistical data base Food and Agriculture Organization (FAOSTAT) 2018. FAO Statistical data base Food and Agriculture Organization of the United Nations, Rome, Italy. Retrieved on 25 June 2018 from http://faostat.fao.org/FERNÁNDEZ, C., LÓPEZ, M. C., & LACHICA, M. (2015). Low-cost mobile open-circuit hood system for measuring gas exchange in small ruminants: from manual to automatic recording. The Journal of Agricultural Science, 153(7), 1302-1309. doi:10.1017/s0021859615000416Fernández, C., Martí, J. V., Pérez-Baena, I., Palomares, J. L., Ibáñez, C., & Segarra, J. V. (2018). Effect of lemon leaves on energy and C–N balances, methane emission, and milk performance in Murciano-Granadina dairy goats. Journal of Animal Science, 96(4), 1508-1518. doi:10.1093/jas/sky028Fernández, C. (2018). Dynamic model development of enteric methane emission from goats based on energy balance measured in indirect open circuit respiration calorimeter. Global Ecology and Conservation, 15, e00439. doi:10.1016/j.gecco.2018.e00439Fernández, C., Pérez-Baena, I., Marti, J. V., Palomares, J. L., Jorro-Ripoll, J., & Segarra, J. V. (2019). Use of orange leaves as a replacement for alfalfa in energy and nitrogen partitioning, methane emissions and milk performance of murciano-granadina goats. Animal Feed Science and Technology, 247, 103-111. doi:10.1016/j.anifeedsci.2018.11.008Fernández, C., Gomis-Tena, J., Hernández, A., & Saiz, J. (2019). An Open-Circuit Indirect Calorimetry Head Hood System for Measuring Methane Emission and Energy Metabolism in Small Ruminants. Animals, 9(6), 380. doi:10.3390/ani9060380Grainger, C., & Beauchemin, K. A. (2011). Can enteric methane emissions from ruminants be lowered without lowering their production? Animal Feed Science and Technology, 166-167, 308-320. doi:10.1016/j.anifeedsci.2011.04.021Howarth, R. (2015). Methane emissions and climatic warming risk from hydraulic fracturing and shale gas development: implications for policy. Energy and Emission Control Technologies, 45. doi:10.2147/eect.s61539Hristov, A. N., Kebreab, E., Niu, M., Oh, J., Bannink, A., Bayat, A. R., … Yu, Z. (2018). Symposium review: Uncertainties in enteric methane inventories, measurement techniques, and prediction models. Journal of Dairy Science, 101(7), 6655-6674. doi:10.3168/jds.2017-13536Ibáñez, C., López, M. C., Criscioni, P., & Fernández, C. (2015). Effect of replacing dietary corn with beet pulp on energy partitioning, substrate oxidation and methane production in lactating dairy goats. Animal Production Science, 55(1), 56. doi:10.1071/an13119Institute Nationale Recherche Agronomique (INRA) 2017. Feeding system for ruminants. Wageningen Academic Publishers, Wageningen, the Netherlands.Jørgensen, S. E. (2015). New method to calculate the work energy of information and organisms. Ecological Modelling, 295, 18-20. doi:10.1016/j.ecolmodel.2014.09.001Kebreab, E., Johnson, K. A., Archibeque, S. L., Pape, D., & Wirth, T. (2008). Model for estimating enteric methane emissions from United States dairy and feedlot cattle1. Journal of Animal Science, 86(10), 2738-2748. doi:10.2527/jas.2008-0960Knapp, J. R., Laur, G. L., Vadas, P. A., Weiss, W. P., & Tricarico, J. M. (2014). 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Replacement of barley grain with lemon pulp on energy partitioning in lactating goats. Unpublished.Merino, P., Ramirez-Fanlo, E., Arriaga, H., del Hierro, O., Artetxe, A., & Viguria, M. (2011). Regional inventory of methane and nitrous oxide emission from ruminant livestock in the Basque Country. Animal Feed Science and Technology, 166-167, 628-640. doi:10.1016/j.anifeedsci.2011.04.081Mills, J. A. N., Kebreab, E., Yates, C. M., Crompton, L. A., Cammell, S. B., Dhanoa, M. S., … France, J. (2003). Alternative approaches to predicting methane emissions from dairy cows1. Journal of Animal Science, 81(12), 3141-3150. doi:10.2527/2003.81123141xMoorby, J. M., Fleming, H. R., Theobald, V. J., & Fraser, M. D. (2015). Can live weight be used as a proxy for enteric methane emissions from pasture-fed sheep? Scientific Reports, 5(1). doi:10.1038/srep17915Niu, M., Kebreab, E., Hristov, A. N., Oh, J., Arndt, C., Bannink, A., … Yu, Z. (2018). Prediction of enteric methane production, yield, and intensity in dairy cattle using an intercontinental database. Global Change Biology, 24(8), 3368-3389. doi:10.1111/gcb.14094Patra, A. K., & Lalhriatpuii, M. (2016). Development of statistical models for prediction of enteric methane emission from goats using nutrient composition and intake variables. Agriculture, Ecosystems & Environment, 215, 89-99. doi:10.1016/j.agee.2015.09.018Pérez-Baena I, Martí JV and Fernández C 2012. Effect of replace barley grain with beet pulp in lactating goats diet; energy balance and milk performance. Unpublished.R Core Team 2016. R: A language and environment for statistical computing. Version 1.1.447. R Foundation for Statistical Computing, Vienna, Austria. Retrieved from https://www.R-project.org/Ramin, M., & Huhtanen, P. (2013). Development of equations for predicting methane emissions from ruminants. 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    Unlocking Antarctic molecular time-capsules – Recovering historical environmental DNA from museum-preserved sponges

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    Marine sponges have recently emerged as efficient natural environmental DNA (eDNA) samplers. The ability of sponges to accumulate eDNA provides an exciting opportunity to reconstruct contemporary communities and ecosystems with high temporal and spatial precision. However, the use of historical eDNA, trapped within the vast number of specimens stored in scientific collections, opens up the opportunity to begin to reconstruct the communities and ecosystems of the past. Here, we define the term ‘heDNA’ to denote the historical environmental DNA that can be obtained from the recent past with high spatial and temporal accuracy. Using a variety of Antarctic sponge specimens stored in an extensive marine invertebrate collection, we were able to recover information on Antarctic fish biodiversity from specimens up to 20 years old. We successfully recovered 64 fish heDNA signals from 27 sponge specimens. Alpha diversity measures did not differ among preservation methods, but sponges stored frozen had a significantly different fish community composition compared to those stored dry or in ethanol. Our results show that we were consistently and reliably able to extract the heDNA trapped within marine sponge specimens, thereby enabling the reconstruction and investigation of communities and ecosystems of the recent past with a spatial and temporal resolution previously unattainable. Future research into heDNA extraction from other preservation methods, as well as the impact of specimen age and collection method, will strengthen and expand the opportunities for this novel resource to access new knowledge on ecological change during the last century

    Carbon sequestration in the deep Atlantic enhanced by Saharan dust

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    Enhanced atmospheric input of dust-borne nutrients and minerals to the remote surface ocean can potentially increase carbon uptake and sequestration at depth. Nutrients can enhance primary productivity, and mineral particles act as ballast, increasing sinking rates of particulate organic matter. Here we present a two-year time series of sediment trap observations of particulate organic carbon flux to 3,000 m depth, measured directly in two locations: the dust-rich central North Atlantic gyre and the dust-poor South Atlantic gyre. We find that carbon fluxes are twice as high and a higher proportion of primary production is exported to depth in the dust-rich North Atlantic gyre. Low stable nitrogen isotope ratios suggest that high fluxes result from the stimulation of nitrogen fixation and productivity following the deposition of dust-borne nutrients. Sediment traps in the northern gyre also collected intact colonies of nitrogen-fixing Trichodesmium species. Whereas ballast in the southern gyre is predominantly biogenic, dust-derived mineral particles constitute the dominant ballast element during the enhanced carbon fluxes in the northern gyre. We conclude that dust deposition increases carbon sequestration in the North Atlantic gyre through the fertilization of the nitrogen-fixing community in surface waters and mineral ballasting of sinking particles

    Measuring enteric methane emissions from individual ruminant animals in their natural environment

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    Ruminant livestock are an important source of meat, milk, fiber, and labor for humans. The process by which ruminants digest plant material through rumen fermentation into useful product results in the loss of energy in the form of methane gas from consumed organic matter. The animal removes the methane building up in its rumen by repeated eructations of gas through its mouth and nostrils. Ruminant livestock are a notable source of atmospheric methane, with an estimated 17% of global enteric methane emissions from livestock. Historically, enteric methane was seen as an inefficiency in production and wasted dietary energy. This is still the case, but now methane is seen more as a pollutant and potent greenhouse gas. The gold standard method for measuring methane production from individual animals is a respiration chamber, which is used for metabolic studies. This approach to quantifying individual animal emissions has been used in research for over 100 years; however, it is not suitable for monitoring large numbers of animals in their natural environment on commercial farms. In recent years, several more mobile monitoring systems discussed here have been developed for direct measurement of enteric methane emissions from individual animals. Several factors (diet composition, rumen microbial community, and their relationship with morphology and physiology of the host animal) drive enteric methane production in ruminant populations. A reliable method for monitoring individual animal emissions in large populations would allow (1) genetic selection for low emitters, (2) benchmarking of farms, and (3) more accurate national inventory accounting
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