Lattice Boltzmann very large eddy simulations of a turbulent flow over covered and uncovered cavities

Microphone measurements in a closed test section wind tunnel are affected by turbulent boundary layer (TBL) pressure fluctuations. These fluctuations are mitigated by placing the microphones at the bottom of cavities, usually covered with a thin, acoustically transparent material. Prior experiments showed that the cavity geometry affects the propagation of TBL pressure fluctuations toward the bottom. However, the relationship between the cavity geometry and the flowfield within the cavity is not well understood. Therefore, a very large-eddy simulation was performed using the lattice Boltzmann method. A cylindrical, a countersunk and a conical cavity are simulated with and without a fine wire-cloth cover, which is modeled as a porous medium governed by Darcy’s law. Adding a countersink to an uncovered cylindrical cavity is found to mitigate the transport of turbulent structures across the bottom by shifting the recirculation pattern away from the cavity bottom. Covering the cavities nearly eliminates this source of hydrodynamic pressure fluctuations. The eddies within the boundary layer, which convect over the cover, generate a primarily acoustic pressure field inside the cavities and thus suggesting that the pressure fluctuations within covered cavities can be modeled acoustically. As the cavity diameter increases compared to the eddies’ integral length scale, the amount of energy in the cut-off modes increases with respect to the cut-on modes. Since cut-off modes decay as they propagate into the cavity, more attenuation is seen. The results are in agreement with experimental evidenc

Herança citoplasmática de pesos ao nascimento e à desmama em bovinos da raça Charolesa.

Efeitos da herança citoplasmática sobre os pesos ao nascimento (PN;N=1521) e aos 205 dias de idade de bezerros da raça Charolesa

Automated, high accuracy classification of Parkinsonian disorders: a pattern recognition approach

Progressive supranuclear palsy (PSP), multiple system atrophy (MSA) and idiopathic Parkinson’s disease (IPD) can be clinically indistinguishable, especially in the early stages, despite distinct patterns of molecular pathology. Structural neuroimaging holds promise for providing objective biomarkers for discriminating these diseases at the single subject level but all studies to date have reported incomplete separation of disease groups. In this study, we employed multi-class pattern recognition to assess the value of anatomical patterns derived from a widely available structural neuroimaging sequence for automated classification of these disorders. To achieve this, 17 patients with PSP, 14 with IPD and 19 with MSA were scanned using structural MRI along with 19 healthy controls (HCs). An advanced probabilistic pattern recognition approach was employed to evaluate the diagnostic value of several pre-defined anatomical patterns for discriminating the disorders, including: (i) a subcortical motor network; (ii) each of its component regions and (iii) the whole brain. All disease groups could be discriminated simultaneously with high accuracy using the subcortical motor network. The region providing the most accurate predictions overall was the midbrain/brainstem, which discriminated all disease groups from one another and from HCs. The subcortical network also produced more accurate predictions than the whole brain and all of its constituent regions. PSP was accurately predicted from the midbrain/brainstem, cerebellum and all basal ganglia compartments; MSA from the midbrain/brainstem and cerebellum and IPD from the midbrain/brainstem only. This study demonstrates that automated analysis of structural MRI can accurately predict diagnosis in individual patients with Parkinsonian disorders, and identifies distinct patterns of regional atrophy particularly useful for this process

Enhancement of the Magnetocaloric Effect in Geometrically Frustrated Cluster Spin Glass Systems

In this work, we theoretically demonstrate that a strong enhancement of the Magnetocaloric Effect is achieved in geometrically frustrated cluster spin-glass systems just above the freezing temperature. We consider a network of clusters interacting randomly which have triangular structure composed of Ising spins interacting antiferromagnetically. The intercluster disorder problem is treated using a cluster spin glass mean-field theory, which allows exact solution of the disordered problem. The intracluster part can be solved using exact enumeration. The coupling between the inter and intracluster problem incorporates the interplay between effects coming from geometric frustration and disorder. As a result, it is shown that there is the onset of cluster spin glass phase even with very weak disorder. Remarkably, it is exactly within a range of very weak disorder and small magnetic field that is observed the strongest isothermal release of entropy.Comment: 10 pages, 7 figures. Provisionally accepted in Journal of Physics: Condensed Matte

Uso de drone no levantamento de ninhos de jacaré-do-pantanal.

Resumo: O manejo de populações de animais silvestres, seja para a finalidade de conservação ou para o aproveitamento econômico, demanda informações sobre sua biologia reprodutiva. A obtenção de informações sobre a reprodução de jacarés do Pantanal é importante tanto para a conservação como para o manejo em vida livre ou para a produção em sistemas onde os ovos são retirados dos ambientes naturais. O modelo oficial de manejo para o uso econômico da espécie em Mato Grosso do Sul permite a coleta de ovos em uma fração do número de ninhos de jacarés encontrados nas propriedades cadastradas a cada ano pelo produtor. Como contrapartida, o órgão licenciador/controlador da atividade no estado, demanda que o produtor forneça informações biológicas verificáveis sobre a população manejada, como a localização individual de cada ninho e número de ovos por ninhos. Entre os habitats usados pelo jacaré-do-pantanal, os tapetes de vegetação flutuantes têm sido especialmente desafiantes para a localização, o monitoramento e o aproveitamento dos ninhos, devido à dificuldade de acesso e de visualização. O estudo apresenta uma metodologia baseada em uma ferramenta nova, barata, eficaz e segura para avaliar o número e a localização individual de ninhos dos jacarés encontrados nos, até então inacessíveis, tapetes de vegetação flutuantes, tanto no Pantanal, como em outras áreas úmidas do Brasil. Abstract: The management of wild animal populations, whether for the purpose of conservation or with a view to economic exploitation, requires information about their reproductive biology. Obtaining information about the reproduction of Yacare caiman is important for both conservation and management in the wild and for production in captivity systems where eggs are removed from natural environments. In this case, the official management model for economic use used in Mato Grosso do Sul allows the collection of a fraction of the number of alligator nests found each year in the ranch by the producer. In counterpart, the licensing / controlling body of the activity demands that the producer provide verifiable biological information about the managed population, e.g., the individual location of each nest and the number of eggs in the nests. Among the habitats used by the Pantanal caiman, the floating vegetation mats have been especially challenging for the location, monitoring and use of the nests, due to their difficulty of access and in viewing. The study presents a methodology based on a new, inexpensive, effective, and safe tool to assess the number and individual location of caimans nests found in hitherto inaccessible floating vegetation mats, both in the Pantanal wetland and in other humid areas in Brazil.bitstream/item/214826/1/Uso-drone-jacare-2020.pd

Yes, they can! Three-banded armadillos Tolypeutes sp. (Cingulata: Dasypodidae) dig their own burrows.

It is believed that the two species of Tolypeutes Illiger, 1811are the only armadillos that do not dig their own burrows, and that these species simply re-use burrows dug by other species. Here, we show that Tolypeutes matacus (Desmarest, 1804) and Tolypeutes tricinctus (Linnaeus, 1758) dig their own burrows. We describe the burrows and three other types of shelters used by them, and provide measurements and frequency of use of the different types of shelter. We have studied free-ranging individuals of T. matacus in two locations in Central Brazil and individuals of T. tricinctus in semi-captivity in the Northeast of Brazil. Individuals of T. matacus were found primarily in small burrows (76%), straw nests (13%), shallow depressions covered with leaf-litter (7%) or in straw nests made on shallow depressions (4%). Adult males and females of T. matacus did not differ in frequency of use of different types of shelter. Sub-adults T. matacus used shallow depressions and nests more often (40%) than adults (22%) and nurslings (10%). Nurslings of T. matacus reused the shelters more frequently (66%), than sub-adults (46%) and adults (35%). Adult females reused burrows and other types of shelter more frequently than adult males. Tolypeutes tricinctus rested mainly in burrows and under leaf-litter, but did not dig depressions or build nests. Tolypeutes tricinctus occasionally used burrows dug by Euphractus sexcinctus (Linnaeus, 1758), but T. matacus never used burrows dug by other species. Nursling T. matacus always shared shelter with an adult female therefore, both used shelters with similar frequency. Adult females and nurslings of T. matacus reused shelters in higher frequency. That can be explained by the fact that adult females with offspring tend to remain for consecutive nights in the same burrow when cubs are recently born. Due to their smaller body size, subadult T. matacus used shelter strategies that require less energetic effort more frequently than adults and nurslings. The habit of covering the burrow entrance with foliage and the burrow?s reduced depth, indicates that Tolypeutes use of burrows is more likely to be related to parental care behavior and thermoregulation strategies than to defense mechanisms. We are confident that the burrows used for resting were indeed dug by Tolypeutes because, besides the direct observation of armadillos digging burrows, the measures of the burrows are very distinctive from those presented as characteristic for the co-occurring burrowing species and are congruent with Tolypeutes size and carapace shape. The newly acquired knowledge that species of Tolypeutes dig burrows can be used to increase the well-being of individuals kept in captivity by adapting enclosures to enable their digging behavior. In addition, this information contributes not only to the study of the ecology and natural history of the species, but can shed new light on the study of the anatomy of specialized diggers. Tolypeutes spp. can comprise the least fossorial of all living armadillo species, but they can no longer be classified as non-diggers

Triatominae (Hemiptera, Reduviidae) in the Pantanal region: association with Trypanosoma cruzi, different habitats and vertebrate hosts.

The transmission cycle of Trypanosoma cruzi in the Brazilian Pantanal region has been studied during the last decade. Although considerable knowledge is available regarding the mammalian hosts infected by T. cruzi in this wetland, no studies have investigated its vectors in this region. This study aimed to investigate the presence of sylvatic triatomine species in different habitats of the Brazilian Pantanal region and to correlate their presence with the occurrences of vertebrate hosts and T. cruzi infection. Methods: The fieldwork involved passive search by using light traps and Noireau traps and active search by visual inspection. The light traps were placed at five selected points along forested areas for seven nights during each of the nine excursions. At each point where a light trap was set, eight Noireau traps were placed in palm trees and bromeliads. Results: In all, 88 triatomine bugs were collected: two and one individuals from light traps and Noireau traps, respectively; three from peridomestic areas; 23 in coati nests; and 59 in thornbird nests. In this study, active search in microhabitats showed higher efficiency than passive search, since 95% of the triatomine bugs were caught in nests. Further, triatomine bugs were only found to be infected by T. cruzi in coati nests. Conclusions: Coati nests might act as a point of convergence and dispersion for triatomine bugs and mammal hosts infected by T. cruzi, thereby playing an important role in the sylvatic cycle of T. cruzi in the Pantanal region

Manejo das forrageiras dos gêneros Brachiaria e Panicum consorciadas com o milho em sistemas de Integração Lavoura-Pecuária.

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