31,373 research outputs found
Global priorities for conservation across multiple dimensions of mammalian diversity
Conservation priorities that are based on species distribution, endemism, and vulnerability may underrepresent biologically unique species as well as their functional roles and evolutionary histories. To ensure that priorities are biologically comprehensive, multiple dimensions of diversity must be considered. Further, understanding how the different dimensions relate to one another spatially is important for conservation prioritization, but the relationship remains poorly understood. Here, we use spatial conservation planning to (i) identify and compare priority regions for global mammal conservation across three key dimensions of biodiversity-taxonomic, phylogenetic, and traits-and (ii) determine the overlap of these regions with the locations of threatened species and existing protected areas. We show that priority areas for mammal conservation exhibit low overlap across the three dimensions, highlighting the need for an integrative approach for biodiversity conservation. Additionally, currently protected areas poorly represent the three dimensions of mammalian biodiversity. We identify areas of high conservation priority among and across the dimensions that should receive special attention for expanding the global protected area network. These high-priority areas, combined with areas of high priority for other taxonomic groups and with social, economic, and political considerations, provide a biological foundation for future conservation planning efforts
Knowledge Acquisition by Networks of Interacting Agents in the Presence of Observation Errors
In this work we investigate knowledge acquisition as performed by multiple
agents interacting as they infer, under the presence of observation errors,
respective models of a complex system. We focus the specific case in which, at
each time step, each agent takes into account its current observation as well
as the average of the models of its neighbors. The agents are connected by a
network of interaction of Erd\H{o}s-Renyi or Barabasi-Albert type. First we
investigate situations in which one of the agents has a different probability
of observation error (higher or lower). It is shown that the influence of this
special agent over the quality of the models inferred by the rest of the
network can be substantial, varying linearly with the respective degree of the
agent with different estimation error. In case the degree of this agent is
taken as a respective fitness parameter, the effect of the different estimation
error is even more pronounced, becoming superlinear. To complement our
analysis, we provide the analytical solution of the overall behavior of the
system. We also investigate the knowledge acquisition dynamic when the agents
are grouped into communities. We verify that the inclusion of edges between
agents (within a community) having higher probability of observation error
promotes the loss of quality in the estimation of the agents in the other
communities.Comment: 10 pages, 7 figures. A working manuscrip
Determinação dos constituintes do leite de vacas de corte de acordo com o período de lactação.
SIEPE. Online
Característica fisico-mecânicos do couro de bovinos cruzados terminados em pastagem recebendo diferentes suplemento.
Avaliaram-se os efeitos do sexo e do nível de proteína bruta no suplemento sobre as características do couro de bovinos em pastejo. Foram utilizados 20 bovinos cruzados (Beefalo x Nelore), sendo 10 machos castrados e 10 fêmeas, terminados em pastagem de Brachiaria decumbens e suplementados por um ano com suplemento (1-kg/animal/dia) contendo 75% NDT (isoenergéticos) e 18% ou 40% de proteína bruta. A taxa de lotação praticada foi 1,5 animal/hectare. Os animais foram abatidos aos 26 meses e tiveram seus couros identificados e processados até a etapa de couro semiacabado (Wet-blue), onde foram retiradas as amostras (25 x 25 cm) da região do dorso-lombar para os ensaios físico-mecânicos, de tração e rasgamento. Foram avaliados o peso da pele ao abate (PPo1), peso da pele padronizada (PPo2), área do couro processado até a etapa de Wet-blue e perdas com o prédescarne. Não houve interação entre sexo e porcentagem de proteína bruta no suplemento. Houve efeito de tratamento para o peso da pele padronizada (PPe2) e para perdas (%). As fêmeas que receberam suplemento com 40% PB apresentaram a menor média para o peso da pele padronizada (25,45 kg) e os machos deste mesmo tratamento apresentaram a maior média (31,60 kg). Não há efeito de sexo e de nível de proteína no suplemento nas características físico-mecânicas do couro de bovinos terminados em pastagem de Brachiaria decumbens
Physicochemical characterization of chondroitin sulfate-co-n-isopropylacrylamide for pharmaceutical purposes.
Realization of Rectangular Artificial Spin Ice and Direct Observation of High Energy Topology
In this letter, we have constructed and experimentally investigated
frustrated arrays of dipoles forming two-dimensional artificial spin ices with
different lattice parameters (rectangular arrays with horizontal and vertical
lattice spacings denoted by and respectively). Arrays with three
different ratios , and are
studied. Theoretical calculations of low-energy demagnetized configurations for
these same parameters are also presented. Experimental data for demagnetized
samples confirm most of the theoretical results. However, the highest energy
topology (doubly-charged monopoles) does not emerge in our theoretical model,
while they are seen in experiments for large enough . Our results also
insinuate that magnetic monopoles may be almost free in rectangular lattices
with a critical ratio , supporting previous
theoretical predictions
Composição do leite de vacas de corte de diferentes grupos genéticos criadas no sul do Brasil.
Genetic association between growth and maternal ability traits in Nelore cattle.
Although body weight traits have been widely used in animal breeding programs due to their importance to beef cattle systems, the use of maternal ability traits, which highly affect the profitability in livestock, is still incipient. As the knowledge of genetic parameters of economic important traits may aid genetic gains, this study was carried out to estimate genetic parameters for weight at 120 and 210 days of age (W120 and W210), pre-weaning average daily gain (PreDG), real fertility (RF), accumulated productivity (AP) and weaning rate (WR). The data set was obtained from Vera Cruz Ranch, a cattle ranch that participates in the Brazilian National Association of Breeders and Researchers (ANCP). Heritabilities and correlations were estimated using univariate and bivariate linear mixed model. The model included contemporary groups (year and season of birth, sex and management group), cow age at calving (in classes and as linear and quadratic covariate) as fixed effects, and genetic and residual components as random effects. Estimates of heritability for between growth and maternal ability traits ranged from 0.22 to 0.32, indicating that they could be improved by direct selection. Estimates of genetic correlation between W120-W210, W120-PreDG, W120-RF, W120-AP, W120-WR were 0.90, 0.54, 0.16, 0.45 and 0.24, respectively. Estimates of genetic correlation between W210-PreDG, W210-RF, W210-AP, W210-WR were 0.63, 0.27, 0.53 and 0.21, respectively. Estimates of genetic correlation between PreDG-RF, PreDG-AP, PreDG-WR were 0.23, 0.16 and 0.28, respectively. Positive genetic correlations were observed between RF, CAP and RD (0.28 to 0.78). Therefore, genetic selection having one of these characteristics as the criterion of selection will lead to an indirect response in the same direction in the others. These results indicate that the use of animals with high breeding values for weights and pre-weaning gain may lead to increase maternal ability traits due to correlated responses. Such responses tend to be bigger when using weight compared to the pre-weaning gain
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