Segregação de recursos por diferentes espécies de morcegos (Mammalia: Chiroptera) na Reserva Biológica de Sooretama

Em ecologia, uma das ideias mais importantes é o princípio da exclusão competitiva, ou Lei de Gause, que afirma que duas espécies competindo pelos mesmos recursos não podem coexistir de modo estável se todos os outros fatores ecológicos forem constantes. Um dos competidores vai sobrepor-se ao outro, levando a um deslocamento evolutivo, morfológico ou comportamental, a um nicho ecológico diferente, ou mesmo à extinção. O horário de atividade diferenciado pode ser um importante fator para evitar competição por espécies proximamente relacionas, sendo assim motivo de interesse nos estudos de exclusão competitiva. O ciclo lunar é importante fator modulador de mamíferos noturnos, podendo também exercer influência na partilha de recursos, onde espécies relacionadas podem responder de diferentes maneiras à iluminação lunar. Analisar as diferenças no horário de atividade de espécies próximas de morcegos trará respostas sobre como uma comunidade partilha a disponibilidade de alimento sobre o critério de tempo. O objetivo foi testar a hipótese de que espécies próximas de morcegos usam o horário de atividade como fator de segregação de recursos. O estudo se deu na Reserva Biológica de Sooretama, importante fragmento de Mata Atlântica ombrófila densa localizada numa região plana no norte do estado do Espírito Santo. A hipótese foi descartada para os grupos de morcegos frugívoros, em análises intra e intergenéricas. Porém, para grupos de insetívoros e nectarívoros, a hipótese de segregação de recursos pelo variável tempo foi sustentada por todos os testes e análises, levando a crer que seja um fator importante nesses grupos

Monitoring of Iberian wolf expansion in Sabugal: Malcata Region

Relatório de projecto no âmbito de Bolsa Universidade de Lisboa/Fundação Amadeu Dias (2008/2009)Departamento de Biologia Animal, Faculdade de Ciências da Universidade de LisboaScholarship Fundação Amadeu Dias/Universidade de LisboaWind farm construction may cause an effect of repulse on the wildlife. Sabugal – Malcata region has a new wind farm in a zone where the situation of the Iberian wolf (Canis lupus signatus, Cabrera 1907) is considered as precarious. In this context a monitoring project was begun to assess the impact of this infrastructure on the Iberian wolf population. Here are presented the results of eight months of monitoring and some information received during the project about the wolf presence in this region. Every month, signs of wolf presence were prospected in twelve transects in the wind farm adjacent area and fourteen inquires were done to people that can contact with this predator. In all the eight months only two scats were detected and two wolf tracks after a snowfall. The presence of wolves was referred in the inquires as constant before 1990. However, some recent livestock damages were reported. The Roe deer (Capreolus capreolus) seems to be in expansion in this area, being reported in more than half of the inquires. This situation may reveal a new opportunity for settlement of dispersing wolves. The occurrence of the Iberian Wolf in Sabugal – Malcata region continues not to be confirmed, but the designation of probable presence is reinforced.Universidade de Lisboa; Fundação Amadeu Dia

Multi-agents adaptive estimation and coverage control using Gaussian regression

We consider a scenario where the aim of a group of agents is to perform the optimal coverage of a region according to a sensory function. In particular, centroidal Voronoi partitions have to be computed. The difficulty of the task is that the sensory function is unknown and has to be reconstructed on line from noisy measurements. Hence, estimation and coverage needs to be performed at the same time. We cast the problem in a Bayesian regression framework, where the sensory function is seen as a Gaussian random field. Then, we design a set of control inputs which try to well balance coverage and estimation, also discussing convergence properties of the algorithm. Numerical experiments show the effectivness of the new approach

MARTA: A high-energy cosmic-ray detector concept with high-accuracy muon measurement

A new concept for the direct measurement of muons in air showers is presented. The concept is based on resistive plate chambers (RPCs), which can directly measure muons with very good space and time resolution. The muon detector is shielded by placing it under another detector able to absorb and measure the electromagnetic component of the showers such as a water-Cherenkov detector, commonly used in air shower arrays. The combination of the two detectors in a single, compact detector unit provides a unique measurement that opens rich possibilities in the study of air showers.Comment: 11 page

Nonuniform Coverage Control on the Line

This paper investigates control laws allowing mobile, autonomous agents to optimally position themselves on the line for distributed sensing in a nonuniform field. We show that a simple static control law, based only on local measurements of the field by each agent, drives the agents close to the optimal positions after the agents execute in parallel a number of sensing/movement/computation rounds that is essentially quadratic in the number of agents. Further, we exhibit a dynamic control law which, under slightly stronger assumptions on the capabilities and knowledge of each agent, drives the agents close to the optimal positions after the agents execute in parallel a number of sensing/communication/computation/movement rounds that is essentially linear in the number of agents. Crucially, both algorithms are fully distributed and robust to unpredictable loss and addition of agents

Strong magnetic exchange and frustrated ferrimagnetic order in a weberite-type inorganic-organic hybrid fluoride

LC acknowledges the University of Liverpool for start-up funding and support. Work at the University of St Andrews was supported by a Leverhulme Research Project Grant. Access to beam time at the ISIS Neutron and Muon Facility was supported by the Science and Technology Facilities Council. The authors also gratefully acknowledge Delphine Toulemon, ITODYS, UMR7086 CNRS, Université Paris VII, for assistance with magnetisation measurements.We combine powder neutron diffraction, magnetometry and 57Fe Mössbauer spectrometry to determine the nuclear and magnetic structures of a strongly interacting weberite-type inorganic-organic hybrid fluoride, Fe2F5(Htaz). In this structure, Fe2+ and Fe3+ cations form magnetically frustrated hexagonal tungsten bronze (HTB) layers of corner sharing octahedra. Our powder neutron diffraction data reveal that, unlike its purely inorganic fluoride weberite counterparts which adopt a centrosymmetric Imma structure, the room- temperature nuclear structure of Fe2F5(Htaz) is best described by a non centrosymmetric Ima2 model with refined lattice parameters a = 9.1467(2) Å, b = 9.4641(2) Å and c = 7.4829(2) Å. Magnetic susceptibility and magnetisation measurements reveal that strong antiferromagnetic exchange interactions prevail in Fe2F5(Htaz) leading to a magnetic ordering transition at TN = 93 K. Analysis of low-temperature powder neutron diffraction data indicates that below TN, the Fe2+ sublattice is ferromagnetic, with a moment of 4.1(1) μB per Fe2+ at 2 K, but that an antiferromagnetic component of 0.6(3) μB cants the main ferromagnetic component of Fe3+, which aligns antiferromagnetically to the Fe2+ sublattice. The zero-field and in-field Mössbauer spectra give clear evidence of an excess of high-spin Fe3+ species within the structure and a non collinear magnetic structure.PostprintPeer reviewe