História de vida de Laetacara aff. araguaiae Ottoni & Costa, 2009 (Perciformes, Cichlidae) em dois riachos no Noroeste do Estado de São Paulo, Brasil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estrutura e composição da ictiofauna de riachos da bacia do Rio Grande no estado de São Paulo, sudeste do Brasil

O ponto médio de cada trecho foi georreferenciado via satélite com receptor GPS e o uso de metodologia padronizada de coleta de dados ambientais e peixes (baseada principalmente na pesca elétrica), possibilitou a obtenção das seguintes informações em cada local: 1) composição taxonômica da ictiofauna e contribuição, em termos de número de indivíduos e biomassa, de cada espécie para a ictiofauna local como um todo; 2) documentação fotográfica de espécimes representativos de cada espécie coletada com sua coloração natural; 3) descrição de cada ambiente coletado, com ilustrações fotográficas coloridas, e seus principais parâmetros bióticos e abióticos. No total foram coletados 3.070 exemplares, pertencentes a seis ordens, 18 famílias, 44 gêneros e 64 espécies, com biomassa total de 14,3 kg. Das espécies coletadas, aproximadamente 50% pertencem a ordem Characiformes, 26,5% a Siluriformes, 11% a Perciformes, 6% a Gymnotiformes, 5% a Cyprinodontiformes e 1,5% a Synbranchiformes. As espécies mais abundantes em termos de número de indivíduos foram Astyanax altiparanae (17,4%) e Hypostomus ancistroides (9%); aquelas com maior biomassa foram A. altiparanae (35%) e Geophagus brasiliensis (9%). em termos de abundância e biomassa por família, a composição da fauna de peixes estudada indica a predominância expressiva de Characidae, seguida por Loricariidae e Cichlidae. Dentre os trechos amostrados, o trecho SG6 (26 espécies) e o PG4 (três espécies), apresentaram a maior e a menor riqueza em espécies, respectivamente, coincidindo com os valores obtidos para o índice de diversidade específica de Shannon-Wiener (H'= 1,08 e 0,26, respectivamente). A riqueza média encontrada foi de 12 espécies por trecho de riacho. Na estimativa de riqueza por extrapolação para o conjunto total de riachos amostrados na bacia do Rio Grande, obtivemos um valor de 93 espécies (erro padrão igual a três) indicando ser necessário um esforço amostral adicional moderado para atingir a assíntota da curva. Das 64 espécies coletadas, quatro (aproximadamente 6% do total) são seguramente novas, sete (aproximadamente 11% do total) possuem status taxonômico ainda indefinido, enquanto outras duas (aproximadamente 3% do total) são espécies certamente introduzidas. Analisando a estrutura trófica e espacial da ictiofauna estudada as 10 espécies numericamente dominantes nos riachos amostrados dividem-se, com base em dados de literatura, em ordem decrescente de importância numérica, em cinco guildas: onívoros nectônicos; invertívoros bentônicos; perifitívoros; algívoros e onívoros bentônicos. Uma chave de identificação para todas as espécies de peixes coletadas durante este estudo é fornecida ao final deste trabalho.

Scaling invariance for the escape of particles from a periodically corrugated waveguide

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The fate of copepod populations in the Paranapanema River (São Paulo, Brazil), downstream from the Jurumirim dam

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Jaguarundi (Puma yagouaroundi) (Geoffroy, 1803) (Carnivora, Felidae) food habits in a mosaic of Atlantic Rainforest and eucalypt plantations of southeastern Brazil

A dieta de uma população de jaguarundi (Puma yagouaroundi) (Geoffroy, 1803) (Carnivora, Felidae) foi estudada entre novembro de 2000 e novembro de 2001, em 24,9 km² de mosaico de Mata Atlântica secundária e reflorestamento de eucalipto na Serra de Paranapiacaba, São Paulo, Brasil. A análise das 26 amostras fecais e regurgitadas, obtidas em 570.1 km de percurso, indicou o consumo de 19 itens alimentares em um total de 74 ocorrências de presas. Pequenos mamíferos foram os itens mais frequentemente encontrados na dieta (42,5%), seguidos por aves (21%), répteis (14%) e mamíferos de tamanho médio (3%). A porcentagem de ocorrência (PO) sugere que a dieta concentra-se, principalmente, em pequenos roedores (30%) e aves (21%). Foi também registrada a predação sobre serpentes da família Viperidae. A amplitude de nicho alimentar padronizada (Bsta = 0,76) mostra uma dieta generalista, entretanto, os dados sugerem que o jaguarundi consome principalmente pequenos vertebrados (mamíferos, aves ou répteis), sobretudo, espécies terrestres.

Description and relationships of Otothyropsis marapoama, a new genus and species of hypoptopomatine catfish (Siluriformes: Loricariidae) from rio Tietê basin, southeastern Brazil

Otothyropsis marapoama, novo gênero e espécie, é descrito baseado em espécimes recentemente coletados em um riacho de cabeceira da porção media do rio Tietê, um rio da bacia do alto rio Paraná no sudeste do Brasil. O novo táxon pertence a um clado que inclui também os gêneros Schizolecis, Otothyris e Pseudotothyris. Otothyropsis marapoama é considerado o grupo-irmão de Pseudotothyris e Otothyris baseado principalmente na presença de vários caracteres derivados da cápsula da bexiga natatória e ossos associados. Vários caracteres pedomórficos compartilhados por Pseudotothyris e Otothyris e seu significado filogenético para a posição deste novo gênero são discutidos.

Estimated frequency of B-chromosomes and population density of Astyanax scabripinnis paranae in a small stream

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Monte Carlo renormalization group with evolution in the space of parameters

Using data from a single simulation we obtain Monte Carlo renormalization-group information in a finite region of parameter space by adapting the Ferrenberg-Swendsen histogram method. Several quantities are calculated in the two-dimensional N 2 Ashkin-Teller and Ising models to show the feasibility of the method. We show renormalization-group Hamiltonian flows and critical-point location by matching of correlations by doing just two simulations at a single temperature in lattices of different sizes to partially eliminate finite-size effects.

Effects of intra-PAG infusion of ovine CRF on defensive behaviors in Swiss-Webster mice

The midbrain dorsal periaqueductal gray (DPAG) is part of the brain defensive system involved in active defense reactions to threatening stimuli. Corticotrophin releasing factor (CRF) is a peptidergic neurotransmitter that has been strongly implicated in the control of both behavioral and endocrine responses to threat and stress. We investigated the effect of the nonspecific CRF receptor agonist, ovine CRF (oCRF), injected into the DPAG of mice, in two predator-stress situations, the mouse defense test battery (MDTB), and the rat exposure test (RET). In the MDTB, oCRF weakly modified defensive behaviors in mice confronted by the predator (rat); e.g. it increased avoidance distance when the rat was approached and escape attempts (jump escapes) in forced contact. In the RET, drug infusion enhanced duration in the chamber while reduced tunnel and surface time, and reduced contact with the screen which divides the subject and the predator. oCRF also reduced both frequency and duration of risk assessment (stretch attend posture: SAP) in the tunnel and tended to increase freezing. These findings suggest that patterns of defensiveness in response to low intensity threat (RET) are more sensitive to intra-DPAG oCRF than those triggered by high intensity threats (MDTB). Our data indicate that CRF systems may be functionally involved in unconditioned defenses to a predator, consonant with a role for DPAG CRF systems in the regulation of emotionality. (c) 2006 Elsevier B.V. All rights reserved.

Kinetics of photoinduced birefringence in the guest-host system of poly(methyl methacrylate) doped with azobenzene-containing crown ethers

The kinetics of the buildup and decay of photoinduced birefringence was examined in a series of host-guest systems: azobenzene-containing crown ethers, differing in the size of the crowns, dissolved in a poly (methyl methacrylate) matrix. In all samples, the kinetics of the buildup of the birefringence was reasonably described by a sum of two exponential functions, the time constants being inversely proportional to the intensity of the pumping light and the magnitudes of the signals at the saturation level depending on the pumping light intensity and sample thickness. The dark decays were best described by the stretched exponential function, with the characteristic parameters (time constant and stretch coefficient) being practically independent of the type of crown ether. The time constants of the signal decay were orders of magnitude shorter than the respective constants of the dark isomerization of the azo crown ethers, thus indicating that the process controlling the decay was a relaxation of the polymer matrix and/or a rearrangement of the flexible parts of the crowns. (C) 2007 Wiley Periodicals, Inc.

NUMERICAL DETERMINATION OF THE ORDER OF PHASE-TRANSITIONS IN ISING SYSTEMS WITH MULTISPIN INTERACTIONS

The method of the fourth-order cumulant of Challa, Landau, and Binder is used together with the Monte Carlo histogram technique of Ferrenberg and Swendsen to study the order of the phase transitions of two-dimensional Ising systems with multispin interactions in the horizontal direction and two-body interactions in the vertical direction.

On epidote fission track dating

The use of epidote in fission track dating was abandoned since the beginning of the 1980s due to difficulties like absence of a standard etching procedure, obtainment of different closure temperatures and the percentage of the datable samples. The results become much more reproducible when restricting fission track analysis to a peculiar kind of track. We are also studying confined track length, what makes possible to obtain information about fossil track annealing. Fission tracks in epidote were successfully etched with 48% HF at 35 degrees C for 12.5 min. Dating samples by the external detector method was not possible due to problems in measuring the efficiency factor held between the number of fossil fission tracks and tracks induced in mica. Dating a sample from Brejui, RN, Brazil with the population method gave a corrected age of 510 +/- 69Ma, in agreement with published U/Th-Pb ages. From the fact that the fossil track length histogram was bimodal, we were able to infer that this sample registered a thermal episode during its history.These preliminary results indicate that epidote deserves further studies to establish whether it can be employed as a thermochronological tool. (c) 2005 Elsevier Ltd. All rights reserved.

First-order-like transition in salt-induced macroion-polyelectrolyte desorption

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Muscle Activation During Four Pilates Core Stability Exercises in Quadruped Position

Queiroz BC, Cagliari MF, Amorim CF, Sacco IC. Muscle activation during four Pilates core stability exercises in quadruped position. Arch Phys Med Rehabil 2010;91: 86-92.Objective: To compare the activity of stabilizing trunk and hip muscles in 4 variations of Pilates stabilizing exercises in the quadruped position.Design: Repeated-measures descriptive study.Setting: A biomechanics laboratory at a university school of medicine.Participants: Healthy subjects (N=19; mean age +/- SD, 31 +/- 5y; mean weight +/- SD, 60 +/- 11 kg; mean height +/- SD, 166 +/- 9cm) experienced in Pilates routines.Interventions: Surface electromyographic signals of iliocostalis, multifidus, gluteus maximus, rectus abdominis, and external and internal oblique muscles were recorded in 4 knee stretch exercises: retroverted pelvis with flexed trunk; anteverted pelvis with extended trunk; neutral pelvis with inclined trunk; and neutral pelvis with trunk parallel to the ground.Main Outcome Measures: Root mean square values of each muscle and exercise in both phases of hip extension and flexion, normalized by the maximal voluntary isometric contraction.Results: The retroverted pelvis with flexed trunk position led to significantly increased external oblique and gluteus maximus muscle activation. The anteverted pelvis with trunk extension significantly increased multifidus muscle activity. The neutral pelvis position led to significantly lower activity of all muscles. Rectus abdominis muscle activation to maintain body posture was similar in all exercises and was not influenced by position of the pelvis and trunk.Conclusions: Variations in the pelvic and trunk positions in the knee stretch exercises change the activation pattern of the multifidus, gluteus maximus, rectus abdominis, and oblique muscles. The lower level of activation of the rectus abdominis muscle suggests that pelvic stability is maintained in the 4 exercise positions.

Escape of particles in a time-dependent potential well

We investigate the escape of an ensemble of noninteracting particles inside an infinite potential box that contains a time-dependent potential well. The dynamics of each particle is described by a two-dimensional nonlinear area-preserving mapping for the variables energy and time, leading to a mixed phase space. The chaotic sea in the phase space surrounds periodic islands and is limited by a set of invariant spanning curves. When a hole is introduced in the energy axis, the histogram of frequency for the escape of particles, which we observe to be scaling invariant, grows rapidly until it reaches a maximum and then decreases toward zero at sufficiently long times. A plot of the survival probability of a particle in the dynamics as function of time is observed to be exponential for short times, reaching a crossover time and turning to a slower-decay regime, due to sticky regions observed in the phase space.