304 research outputs found

    On the stochastic mechanics of the free relativistic particle

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    Given a positive energy solution of the Klein-Gordon equation, the motion of the free, spinless, relativistic particle is described in a fixed Lorentz frame by a Markov diffusion process with non-constant diffusion coefficient. Proper time is an increasing stochastic process and we derive a probabilistic generalization of the equation (dτ)2=1c2dXνdXν(d\tau)^2=-\frac{1}{c^2}dX_{\nu}dX_{\nu}. A random time-change transformation provides the bridge between the tt and the τ\tau domain. In the τ\tau domain, we obtain an \M^4-valued Markov process with singular and constant diffusion coefficient. The square modulus of the Klein-Gordon solution is an invariant, non integrable density for this Markov process. It satisfies a relativistically covariant continuity equation

    Diversidade de espécies e densidade de ninhos de abelhas sociais sem ferrão (Hymenoptera, Apidae, Meliponinae) em floresta de terra firme na Amazônia Central.

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    Stingless bees were collected between 1984 and 1990 in continuous forest, forest fragments and cleared areas 90 Km north of Manaus, Amazonas, Brazil. Several methods were employed. a total of 54 species of 21 genera were collected including two undescribed species of Plebeia Schwarz, 1938. The most abundant genera were Trigona Jurine, 1807; Melipona Illiger, 1806; Partamona Schwarz, 1939 and Tetragona Lepeletier, 1825. The most abundant species were Trigona crassipes (Fabricius, 1793) and T. fulviventris Guérin, 1835. Fruit fly traps baited with fragrances for euglossine bees showed to be an useful method for stingless bee collection too. The study area showed a great richness in relation to other regions of the world. However the density of nests found from a 100ha area of continuous forest were low (1 nest/6.67ha). The consequences of deforestation on stingless bees populations and of the decrease of these on the forest conservation are also discussed

    Educação, pesquisa, extensão e conservação na paisagem fragmentada, uma conciliação necessária.

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    A Fazenda Experimental Catuaba (FEC), o antigo seringal, é um sítio consolidado para ações de ensino, pesquisa e extensão da Universidade Federal do Acre (UFAC). Ela provê suporte para atividades de grupos de pesquisa, para estudantes do ensino médio e de cursos de graduação e de pós-graduação, e para treinamentos, oficinas e cursos de capacitação, todas alinhadas com um dos principais objetivos da Convenção da Diversidade Biológica, a conservação da biodiversidade e dos serviços ecossistêmicos. Este capítulo sintetiza os resultados principais dos 30 anos de pesquisas realizadas na FEC e alerta para a diminuição do número de fragmentos e para o aumento da extensão das bordas no seu entorno e para a perda de biomassa, de biodiversidade e de serviços ecossistêmicos, em função dos efeitos do fogo e do desmatamento. Ele destaca a importância da UFAC efetuar o Cadastro Ambiental Rural e o Plano de Recuperação Ambiental (PRA) da FEC, e aponta para a perspectiva de abertura de um caminho para a integração com os PRAs do entorno e a viabilização da tão necessária conectividade com fragmentos vizinhos. A conectividade dos remanescentes da paisagem fragmentada é possível, envolve a integração de propriedades e a restauração de área de preservação permanente dos igarapés da FEC, e pode integrar, de fato, pelo menos dois fragmentos de cerca de 900 hectares, dobrando a sua efetividade. The Fazenda Experimental Catuaba (FEC), the former rubber production forest, is a consolidated site for teaching, research and extension activities at the Federal University of Acre (UFAC). It provides support for activities of research groups, for high school students and for undergraduate and graduate courses, and for training, workshops and courses, all aligned with one of the main objectives of the Convention on Biological Diversity, the conservation of biodiversity and ecosystem services. This chapter summarizes the main results of the 30 years of research carried out at FEC and presents warnings and concerns of the decrease in the number of fragments and the increase in the extent of the edges in its surroundings and the loss of biomass, biodiversity and ecosystem services due to the effects of fire and deforestation. It also highlights the importance of UFAC making the Rural Environmental Registry and the Environmental Recovery Plan (PRA) of the FEC, and points to the prospect of opening a path for integration with the surrounding PRAs and enabling the much needed connectivity among neighboring fragments. The connectivity of the remnants of the fragmented landscape is possible and it involves the integration of properties and the restoration of the permanent preservation area of the FEC streams, and can in fact integrate at least two fragments of around 900 hectares, doubling their effectiveness.bitstream/item/219530/1/27084.pd

    NEOTROPICAL CARNIVORES: a data set on carnivore distribution in the Neotropics

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    Incluye contenido parcial de los autoresAbstract.Mammalian carnivores are considered a key group in maintaining ecologicalhealth and can indicate potential ecological integrity in landscapes where they occur. Carni-vores also hold high conservation value and their habitat requirements can guide managementand conservation plans. The order Carnivora has 84 species from 8 families in the Neotropicalregion: Canidae; Felidae; Mephitidae; Mustelidae; Otariidae; Phocidae; Procyonidae; andUrsidae. Herein, we include published and unpublished data on native terrestrial Neotropicalcarnivores (Canidae; Felidae; Mephitidae; Mustelidae; Procyonidae; and Ursidae). NEOTRO-PICAL CARNIVORES is a publicly available data set that includes 99,605 data entries from35,511 unique georeferenced coordinates. Detection/non-detection and quantitative data wereobtained from 1818 to 2018 by researchers, governmental agencies, non-governmental organi-zations, and private consultants. Data were collected using several methods including cameratrapping, museum collections, roadkill, line transect, and opportunistic records. Literature(peer-reviewed and grey literature) from Portuguese, Spanish and English were incorporated inthis compilation. Most of the data set consists of detection data entries (n=79,343; 79.7%) butalso includes non-detection data (n=20,262; 20.3%). Of those, 43.3% also include count data(n=43,151). The information available in NEOTROPICAL CARNIVORES will contribute tomacroecological, ecological, and conservation questions in multiple spatio-temporal perspec-tives. As carnivores play key roles in trophic interactions, a better understanding of their distri-bution and habitat requirements are essential to establish conservation management plans andsafeguard the future ecological health of Neotropical ecosystems. Our data paper, combinedwith other large-scale data sets, has great potential to clarify species distribution and relatedecological processes within the Neotropics. There are no copyright restrictions and no restric-tion for using data from this data paper, as long as the data paper is cited as the source of theinformation used. We also request that users inform us of how they intend to use the data

    The Schroedinger Problem, Levy Processes Noise in Relativistic Quantum Mechanics

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    The main purpose of the paper is an essentially probabilistic analysis of relativistic quantum mechanics. It is based on the assumption that whenever probability distributions arise, there exists a stochastic process that is either responsible for temporal evolution of a given measure or preserves the measure in the stationary case. Our departure point is the so-called Schr\"{o}dinger problem of probabilistic evolution, which provides for a unique Markov stochastic interpolation between any given pair of boundary probability densities for a process covering a fixed, finite duration of time, provided we have decided a priori what kind of primordial dynamical semigroup transition mechanism is involved. In the nonrelativistic theory, including quantum mechanics, Feyman-Kac-like kernels are the building blocks for suitable transition probability densities of the process. In the standard "free" case (Feynman-Kac potential equal to zero) the familiar Wiener noise is recovered. In the framework of the Schr\"{o}dinger problem, the "free noise" can also be extended to any infinitely divisible probability law, as covered by the L\'{e}vy-Khintchine formula. Since the relativistic Hamiltonians |\nabla | and +m2m\sqrt {-\triangle +m^2}-m are known to generate such laws, we focus on them for the analysis of probabilistic phenomena, which are shown to be associated with the relativistic wave (D'Alembert) and matter-wave (Klein-Gordon) equations, respectively. We show that such stochastic processes exist and are spatial jump processes. In general, in the presence of external potentials, they do not share the Markov property, except for stationary situations. A concrete example of the pseudodifferential Cauchy-Schr\"{o}dinger evolution is analyzed in detail. The relativistic covariance of related waveComment: Latex fil

    Paternity testing and behavioral ecology: a case study of jaguars (Panthera onca) in Emas National Park, Central Brazil.

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    We used microsatellite loci to test the paternity of two male jaguars involved in an infanticide event recorded during a long-term monitoring program of this species. Seven microsatellite primers originally developed for domestic cats and previously selected for Panthera oncawere used. In order to deal with uncertainty in the mother?s genotypes for some of the loci, 10000 values of Wwere derived by simulation procedures. The male that killed the two cubs was assigned as the true sire. Although the reasons for this behavior remain obscure, it shows, in principle, a low recognition of paternity and kinship in the species. Since the two cubs were not very young, one possibility is that the adult male did not recognize the cubs and killed them for simple territorial reasons. Thus, ecological stress in this local population becomes a very plausible explanation for this infanticide, without further sociobiological implications

    Monitoring the complex benthic habitat on semi-dark underwater marine caves using photogrammetry-based 3D reconstructions

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    Marine caves are dark environments considered a priority habitat for conservation included in the EU Habitats Directive (H8330). They harbor fragile benthic communities and represent a major reservoir of marine biodiversity. However, there is a lack of knowledge of these habitats due to the difficulties of creating detailed benthic maps and characterizing the biodiversity, structure, and dynamics of their communities. The uniqueness of marine caves fosters their popularity among recreational divers, who can cause disturbances through abrasion of the biota, resuspension of sediment, and accumulation of exhaled air bubbles in the caves' ceilings. This study aims to build a monitoring framework to characterize the structure and temporal dynamics of this complex habitat using Structurefrom- Motion (SfM) photogrammetry. SfM is a novel, non-invasive technique that allows a major advancement in the monitoring of changes in the cave’s community assemblages. This method relies on images acquired by 4K video footage to build fine-scaled 3D digital models of the substrate using overlapping imagery. For this study, we combined SfM photogrammetry and photo quadrats extracted from the video recordings. We evaluate the effectiveness of this methodology in a marine cave highly frequented by divers, located in Illa de l’Aire (Balearic Islands, Spain), and carried out two surveys before and after the diving season (2019-2021). As a result, we found a loss of 25 colonies of bryozoans with fragile skeletons, like Schizoretepora sp., and 8 individual sponges with globose morphotypes. Our results indicate that this methodology enables accurate and efficient monitoring of benthic communities in underwater caves that allow us to better understand their dynamics and, therefore, to develop the need management measures

    The step of incorporation of Bacillus coagulans GBI-30 6086 into “requeijão cremoso” processed cheese does not affect metabolic homeostasis of rats

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    Dairy product consumption is a common habit in Brazil. These products present a good matrix for probiotic incorporation. Thus, in this study the feasibility of producing a probiotic "requeijao cremoso" incorporated with Bacillus coagulans GBI-30 6086 in three different steps and its metabolic effect in an animal model for 2 weeks has been evaluated. Wistar adult health rats were randomized into one to five groups (n = 8 for each group): Control (C); "requeijao cremoso" without probiotic (RC); probiotic inoculated in the milk before pasteurization at 65 degrees C/30 min (RPP); "requeijao cremoso" inoculated before the fusion step and consequently exposed to 90 degrees C/5 min (RPF); and "requeijao cremoso" inoculated after fusion step, i.e., once the product temperature reached 50 degrees C (RPAF). At the end of treatment, analysis of molecular markers of proteins of stress and antioxidant system, HSP 25, 60, 70 and 90, SOD and catalase were performed in the animals' muscles by Western Blot technique. The HSP25, HSP90 and catalase levels of C, RPP, RPF, and RPAF were similar, indicating that the homeostasis remained unchanged. The incorporation of B. coagulans GBI-30 6086 in the "requeijao cremoso" was shown to be stable and the microorganism remained viable in all steps tested. The incorporation of the probiotic strain in the fusion stage facilitated the technological process, since it allowed a better homogenization of the product and did not affect the maintenance of the metabolic homeostasis of rats10CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPsem informação302763/2014-7; 305804/2017-013/21544-9; 18/24540-8; 2019/21188-
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