Simulating Male Selfish Strategy in Reproduction Dispute

We introduce into the Penna Model for biological ageing one of the possible male mechanisms used to maximize the ability of their sperm to compete with sperm from other males. Such a selfish mechanism increases the male reproduction success but may decrease the survival probability of the whole female population, depending on how it acts. We also find a dynamic phase transition induced by the existence of an absorbing state where no selfish males survive.Comment: 7 pages, latex including 2 eps figure

Caracterização da variação diária e sazonal do CO2 atmosférico em cultivo da palma de óleo com híbridos interespecíficos (Elaeis guineensis X Elaeis oleifera) no Leste da Amazônia.

Estudos acerca das mudanças climáticas constataram que o aumento substancial da concentração de gases do efeito estufa na atmosfera (GEE), como o dióxido de carbono (CO2), poderá causar consequências ao meio ambiente e aos seres vivos em diversos aspectos, sobretudo em regiões de grande biodiversidade, como a Amazônia. A região possui uma grande extensão de áreas degradadas oriundas principalmente de desmatamentos. Atualmente têm-se investido no cultivo de culturas perenes como a palma de óleo (Elaeis guineensis Jacq.) visando recuperar estas áreas. Medidas contínuas do perfil vertical da concentração do CO2 atmosférico ([CO2]) foram obtidas durante os meses de março a junho de 2014 em plantio com híbridos interespecíficos da palma de óleo, na empresa Marborges Agroindústria S.A., Moju, Pará. Esse período compreendeu o máximo da estação chuvosa e a transição para a estação seca no leste da Amazônia. Durante o período noturno, [CO2] aumentou nos níveis próximos do solo, atingindo valores de até 393 ppm. E, durante o diurno, a menor [CO2] foi igual a 379 ppm, observada à altura média da copa (~6 m). A curva média da variação diária da [CO2] mostrou um decréscimo próximo às 7h30 e voltou a aumentar às 18h

GHASP: an H{\alpha} kinematic survey of spiral and irregular galaxies -- IX. The NIR, stellar and baryonic Tully-Fisher relations

We studied, for the first time, the near infrared, stellar and baryonic Tully-Fisher relations for a sample of field galaxies taken from an homogeneous Fabry-Perot sample of galaxies (the GHASP survey). The main advantage of GHASP over other samples is that maximum rotational velocities were estimated from 2D velocity fields, avoiding assumptions about the inclination and position angle of the galaxies. By combining these data with 2MASS photometry, optical colors, HI masses and different mass-to-light ratio estimators, we found a slope of 4.48\pm0.38 and 3.64\pm0.28 for the stellar and baryonic Tully-Fisher relation, respectively. We found that these values do not change significantly when different mass-to-light ratios recipes were used. We also point out, for the first time, that rising rotation curves as well as asymmetric rotation curves show a larger dispersion in the Tully-Fisher relation than flat ones or than symmetric ones. Using the baryonic mass and the optical radius of galaxies, we found that the surface baryonic mass density is almost constant for all the galaxies of this sample. In this study we also emphasize the presence of a break in the NIR Tully-Fisher relation at M(H,K)\sim-20 and we confirm that late-type galaxies present higher total-to-baryonic mass ratios than early-type spirals, suggesting that supernova feedback is actually an important issue in late-type spirals. Due to the well defined sample selection criteria and the homogeneity of the data analysis, the Tully-Fisher relation for GHASP galaxies can be used as a reference for the study of this relation in other environments and at higher redshifts.Comment: 16 pages, 6 figures. Accepted for publication in MNRA

Marcadores moleculares em morangueiro.

bitstream/item/98228/1/Documento-379-WEB.pd

Ising Ferromagnet: Zero-Temperature Dynamic Evolution

The dynamic evolution at zero temperature of a uniform Ising ferromagnet on a square lattice is followed by Monte Carlo computer simulations. The system always eventually reaches a final, absorbing state, which sometimes coincides with a ground state (all spins parallel), and sometimes does not (parallel stripes of spins up and down). We initiate here the numerical study of ``Chaotic Time Dependence'' (CTD) by seeing how much information about the final state is predictable from the randomly generated quenched initial state. CTD was originally proposed to explain how nonequilibrium spin glasses could manifest equilibrium pure state structure, but in simpler systems such as homogeneous ferromagnets it is closely related to long-term predictability and our results suggest that CTD might indeed occur in the infinite volume limit.Comment: 14 pages, Latex with 8 EPS figure

Water diffusion in rough carbon nanotubes

We use molecular dynamics simulations to study the diffusion of water inside deformed carbon nanotubes with different degrees of deformation at 300 K. We found that the number of hydrogen bonds that water forms depends on nanotube topology, leading to enhancement or suppression of water diffusion. The simulation results reveal that more realistic nanotubes should be considered to understand the confined water diffusion behavior, at least for the narrowest nanotubes, when the interaction between water molecules and carbon atoms is relevant.Comment: 17 pages, 8 figure