Infanticide and infant defence by males--modelling the conditions in primate multi-male groups

Infanticide by primate males was considered rare if groups contain more than one adult male because, owing to lower paternity certainty, a male should be less likely to benefit from infanticide. Guided by recent evidence for strong variation of infanticide in primate multi-male groups, we modelled the conditions for when infanticide should occur for a group with a resident and an immigrant male. Setting the parameters (e.g. infant mortality, reduction of interbirth interval, life-time reproductive success, genetic representation) to fit the conditions most commonly found in nature, we develop a game-theoretic model to explore the influence of age and dominance on the occurrence of infanticide and infant defence. Male age strongly impacts the likelihood of an attack which is modified by the father's defence. If the new male is dominant he is likely to attack under most circumstances whereas a subordinate male will only attack if the father does not defend. These model scenarios fit the conditions under which infanticide is known to occur in primate multi-male groups and offer an explanation why infanticide is common in some multi-male groups and rare in others. Overall, the benefits for infanticidal males are strongly governed by a reduced interbirth interval while advantages via improved genetic representation in the gene pool contribute but a minor fraction

Forecast of Total Electron Content over Europe for disturbed ionospheric Conditions

A general picture of the occurrence of ionospheric storms as function of local time, season and location is known from numerous studies over the past 50 years. Nevertheless, it is not yet possible to say how the ionosphere will actually respond to a given space weather event because the measurements of the onset time, location of maximum perturbation, amplitude and type of storm (positive or negative) deviate much from the climatology. However, statistical analyses of numerous storm events observed in the Total Electron Content (TEC) since 1995 enable to estimate and predict a most probable upcoming perturbed TEC over Europe based on forecasts of geomagnetic activity. A first approach will be presented here. The forecast of perturbed TEC is part of the Forecast System Ionosphere build under the umbrella of the FP7 project AFFECTS∗ (Advanced Forecast For Ensuring Communication Through Space). It aims to help users mitigating the impact on communication system

Quantum Quench of an Atomic Mott Insulator

We study quenches across the Bose-Hubbard Mott-insulator-to-superfluid quantum phase transition using an ultra-cold atomic gas trapped in an optical lattice. Quenching from the Mott insulator to superfluid phase is accomplished by continuously tuning the ratio of Hubbard tunneling to interaction energy. Excitations of the condensate formed after the quench are measured using time-of-flight imaging. We observe that the degree of excitation is proportional to the fraction of atoms that cross the phase boundary, and that the quantity of excitations and energy produced during the quench have a power-law dependence on the quench rate. These phenomena suggest an excitation process analogous to the Kibble-Zurek (KZ) mechanism for defect generation in non-equilibrium classical phase transitions

Structure and Activation Mechanism of the Drosophila Initiator Caspase Dronc

Activation of an initiator caspase is essential to the execution of apoptosis. The molecular mechanisms by which initiator caspases are activated remain poorly understood. Here we demonstrate that the autocatalytic cleavage of Dronc, an important initiator caspase in Drosophila, results in a drastic enhancement of its catalytic activity in vitro. The autocleaved Dronc forms a homodimer, whereas the uncleaved Dronc zymogen exists exclusively as a monomer. Thus the autocatalytic cleavage in Dronc induces its stable dimerization, which presumably allows the two adjacent monomers to mutually stabilize their active sites, leading to activation. Crystal structure of a prodomain-deleted Dronc zymogen, determined at 2.5 Å resolution, reveals an unproductive conformation at the active site, which is consistent with the observation that the zymogen remains catalytically inactive. This study revealed insights into mechanism of Dronc activation, and in conjunction with other observations, suggests diverse mechanisms for the activation of initiator caspases

Early Warning of ionospheric disturbances for GNSS users

Temporal and spatial gradients in the ionosphere can cause major threats on communication and navigation satellite systems, because the propagation of transionospheric radio signals is influenced by the ionospheric electron content. Space weather events are often the source of strong ionospheric disturbances. Forecasting ionospheric perturbations related to space weather events is therefore a crucial task being of special interest for GNSS users. The climatology of ionospheric storms seen in the Total Electron Content (TEC) over Europe as a response of the ionosphere towards Earth oriented space weather events is well known. It depends on season, elapsed time from event arrival, location and local time. However, the deviation of a single storm to the mean behavior can be large. A good correlation between strength of the ionospheric storm, i.e. the maximum deviation of the TEC to 27 day median, to solar wind or geomagnetic activity indices is hard to define. Hence forecasting TEC for disturbed conditions is a challenging task. However, the storm climatology and comprehensive correlation studies allow forecasting of the most probable TEC perturbation amplitude for the European region. GNSS users are in need of information about arriving threads due to space weather events as early as possible. Therefore, an Early Warning message for GNSS users has been developed at the DLR within the FP7-Project AFFECTS. It provides information about Earth endangering space weather events to interested GNSS users up to two days before their arrival. Additional information are now added by a second warning message distributed thirty minutes before arrival at Earth giving more specific information like exact arrival time, forecasts of geomagnetic indices, approximate TEC perturbation and range error for the European region. An overview on the Early Warning for GNSS user service provided by DLR is presented in this paper

Bolivia en el contexto de la crisis económica internacional

The current research has the aim to identify and evaluate the impacts of external shocks related to the new economic context of world-wide deceleration in the Bolivian economy. It is assumed for this scenario that Bolivia would face a reduction in the export prices, a reduction in the level of foreign direct investment, a fall in the remittances and a decline in the government expenditure. In order to evaluate these effects in the short and medium term, we use a dynamic General Equilibrium Computable Model (CGE), in a horizon of ten years. The exercise was realized on the basis of the following experiments: i) an adverse shock in terms of trade, ii) a negative shock in the level of government spending, iii) a negative shock in the level of remittances and direct foreign investment (DFI

Uso reflexivo de los manuales escolares de historia: Resultados de una encuesta realizada a docentes, alumnos y universitarios

Este estudio forma parte de un amplio proyecto, «PARA la conciencia histórica», y se centra en los manuales escolares. Los autores se preguntan: ¿Qué esperan los alumnos de los libros de texto? ¿Cómo se utilizan realmente? ¿Hasta qué punto se comprenden e introducen una concepción adecuada de la historia? Como resultado de reunir diversos materiales, rigurosamente construidos y analizados, los autores llegan a conclusiones poco satisfactorias respecto a la posible construcción de la «conciencia histórica» a través de los libros de texto.This paper is part of a wide project «FOR historical consciousness» and focuses on school manuals. The authors ask the following questions: What do students expect from textbooks? How are they really used? How far are they understood and up to what point do they introduce an adequate concept of history? After having gathered different materials and rigorously built and analysed them, the authors reach not very satisfactory conclusions with respect to a possible building of a «historical consciousness» through textbooks.Este estudio forma parte de un amplio proyecto, «PARA la conciencia histórica», y se centra en los manuales escolares. Los autores se preguntan: ¿Qué esperan los alumnos de los libros de texto? ¿Cómo se utilizan realmente? ¿Hasta qué punto se comprenden e introducen una concepción adecuada de la historia? Como resultado de reunir diversos materiales, rigurosamente construidos y analizados, los autores llegan a conclusiones poco satisfactorias respecto a la posible construcción de la «conciencia histórica» a través de los libros de texto