Macroecology of parental care in arthropods: higher mortality risk leads to higher benefits of offspring protection in tropical climates

The intensity of biotic interactions varies around the world, in such a way that mortality risk imposed by natural enemies is usually higher in the tropics. A major role of offspring attendance is protection against natural enemies, so the benefits of this behaviour should be higher in tropical regions. We tested this macroecological prediction with a meta-regression of field experiments in which the mortality of guarded and unguarded broods was compared in arthropods. Mortality of unguarded broods was higher, and parental care was more beneficial, in warmer, less seasonal environments. Moreover, in these same environments, additional lines of defence further reduced offspring mortality, implying that offspring attendance alone is not enough to deter natural enemies in tropical regions. These results help to explain the high frequency of parental care among tropical species and how biotic interactions influence the occurrence of parental care over large geographic scales. Finally, our findings reveal that additional lines of defences – an oftentimes neglected component of parental care – have an important effect on the covariation between the benefits of parental care and the climate-mediated mortality risk imposed by natural enemies

Dynamics of gyrostat satellite subject to gravitational torque: Investigation of equilibria

Dynamics of gyrostat satellite moving along a circular orbit in the central Newtonian gravitational field is investigated. A symbolic-numerical method for determining all equilibrium orientations of gyrostat satellite in the orbital coordinate system with given gyrostatic torque and given principal central moments of inertia is proposed. Conditions of equilibriums existence are obtained depending on four dimensionless parameters of the system. All bifurcational values of parameters at which there is a change of numbers of equilibrium orientations are determined. Evolution of domains in the space of parameters which correspond to various numbers of equilibria are carried out in detail. Relationship with axisymmetrical cases of satellite gyrostat is considered. It is shown that the number of equilibria of the gyrostat satellite in general case not be less than 8 and not more than 24.Исследована динамика спутника-гиростата, движущегося в центральном ньютоновом силовом поле по круговой орбите. Предложен метод определения всех положений равновесия спутника-гиростата в орбитальной системе координат при заданных значениях вектора гиростатического момента и главных центральных моментов инерции и получены условия их существования в зависимости от четырех безразмерных параметров системы. Найдены бифуркационные значения параметров, при которых изменяется число положений равновесия. Проведен детальный численный анализ эволюции областей существования различного числа равновесий в пространстве безразмерных параметров. Рассмотрена взаимосвязь полученных областей существования с областями существования равновесий осесимметричного спутника. Показано, что число положений равновесия спутника-гиростата в общем случае не превышает 24 и не может бытьменьше 8.Fundação para a Ciência e a Tecnologiainfo:eu-repo/semantics/publishedVersio

Temperature inversion symmetry in the Casimir effect with an antiperiodic boundary condition

We present explicitly another example of a temperature inversion symmetry in the Casimir effect for a nonsymmetric boundary condition. We also give an interpretation for our result.Comment: 4 page

Métodos de regiões de confiança para resolução do problema de quadrados mínimos: implementação e testes numéricos

The least squares problem has many applications in the field of optimization. In the present work, we use two strategies for its resolution: Levenberg-Marquardt and Conjugate Gradients. Each one exploits some problem features, and both are globalized by the trust-region strategy. Our contribution consists in the implementation of both methods using the CAS Maxima and in the comparative analysis of these methods in the resolution of a family of least squares problems from the literature.O problema de quadrados mínimos possui várias aplicações no campo de otimização. No presente trabalho, abordamos duas estratégias para sua resolução: Levenberg-Marquardt e Gradientes Conjugados. Cada uma explora características próprias do problema, e ambas usam regiões de confiança para a globalização. Nossa contribuição está na implementação de ambos os métodos no CAS Maxima e na análise comparativa do desempenho desses métodos na resolução de uma família de problemas de quadrados mínimos da literatura.698

POTENCIALIDADES EDUCATIVAS DE ASPECTOS GEOMORFOLÓGICOS DA SERRA DOS TAPUIAS – BAHIA.

O presente artigo discute a potencialidade didática de dois sítios geomorfológicos da Serra dos Tapuias, município de Riachão das Neves, Bahia. Para sua realização foram realizadas busca de referencial teórico, reconhecimento em campo para compartimentação da paisagem e técnicas de inventariação e avaliação de patrimônio geológico segundo seu caráter educativo. Após análise percebe-se que as áreas configuram-se com potencial para a instituição de práticas ligadas a educação ambiental

A spherical perfect lens

It has been recently proved that a slab of negative refractive index material acts as a perfect lens in that it makes accessible the sub-wavelength image information contained in the evanescent modes of a source. Here we elaborate on perfect lens solutions to spherical shells of negative refractive material where magnification of the near-field images becomes possible. The negative refractive materials then need to be spatially dispersive with $\epsilon(r) \sim 1/r$ and $\mu(r)\sim 1/r$. We concentrate on lens-like solutions for the extreme near-field limit. Then the conditions for the TM and TE polarized modes become independent of $\mu$ and $\epsilon$ respectively.Comment: Revtex4, 9 pages, 2 figures (eps

Preservation of sliced cooked ham at 25, 30 and 37°C under moderated pressure (hyperbaric storage) and comparison with refrigerated storage

The feasibility of hyperbaric storage (HS) to substitute refrigeration as a lower energetic cost alternative to refrigeration, for sliced cooked ham preservation was assessed by using temperatures and pressures ranging 25–37◦C and 25–150 MPa for 4 and 8 h. At microbiological level, storage at 25 ◦C, 30 ◦C, and 37 ◦C, showed no effect on microbial growth at 25 MPa reaching levels similar to atmospheric pressure storage, around 5 log CFU/g for both total aerobic mesophiles (TAM) and lactic acid bacteria (LAB). Nevertheless, the storage at 50 MPa and 30 ◦C resulted in microbial growth inhibition, resulting in TAM and LAB counts similar to refrigeration, of about 3.8 log CFU/g for both the microorganisms. Additionally, the increase of the storage pressure to 100–150 MPa resulted in microbial inacti-vation, leading to microbial loads of almost 1 log CFU/g lower than refrigeration. In general, hyperbaric stored sliced cooked ham showed physicochemical parameters similar to the refrigerated samples. In conclusion, these results show that HS at uncontrolled (naturally variable room tem-perature conditions at 25–37 ◦C) is a promising alternative to refrigeration for cooked ham preservation. To this new preservation technology, no energetic costs are associated throughout storage, compared to refrigeration, needing only energy to generate the pressure and decompress, since no energy is required to maintain the pressure

Shelf-life extension of watermelon juice preserved by hyperbaric storage at room temperature compared to refrigeration

This work reports Hyperbaric Storage (HS) preservation of raw watermelon juice at variable/uncontrolled room temperature (RT,z21 C) for 7 days at 100 MPa and compared it with refrigeration (RF). At the end of storage, there was an increase in microbial counts (total aerobic mesophiles, psychrophiles, and yeasts and moulds) to above 6 log10 CFU/mL for samples stored at atmospheric pressure (RF and RT), while juice stored under HS/RT showed maximum values of about 2 log10 CFU/mL for total aerobic mesophiles/ psychrophiles and below the detection limit for yeasts and moulds. HS/RT juice showed also physicochemical parameters at levels similar to the initial juice. Thus, HS/RT can not only be used to preserve foods with no refrigeration energetic costs (since it does not require temperature control), but additionally, has also a great potential to extend the shelf-life of food products, compared to RF. This is the first case in the literature showing this additional potential/advantage of HS/RT