Diversity and health traits of local landraces of runner bean (Phaseolus coccineus L.) from Spain

Diversity and health traits of local landraces of runner bean (Phaseolus coccineus L.) from Spain

Local variability of serotinous cones in a Canary Island pine (Pinus canariensis) stand

The endemic Canary Island pine (Pinus canariensis) has an effective strategy to counteract fire disturbance in the short term. It has a mixed strategy that combines the presence of serotinous cones and thick barks with the ability to re-sprout from the trunk after a fire, a rare trait in pine species. High frequency of fires in the Canary Islands is related to human action, as natural fires by lightning or vulcan activity have very low frequency; hence, the how and whys of the presence of serotinous cones in the species is still a topic of debate. Previous studies showed that the frequency of serotinous cones varies from stand to stand. Here, we analyzed the presence of serotinous cones at a local scale. We selected a Canary Island pine stand in the transition zone between dry and humid forests in the south of Tenerife. Branches were pruned from 20 trees in order to evaluate the presence of serotinous vs. non-serotinous cones by direct verticile counting on the branches. The opening temperature of serotinous cones was assessed in the laboratory. Percentages of serotinous vs. non-serotinous cones varied from 0 to 93 %, showing high variability between trees. Opening temperatures were very high (above 65 ºC) as compared to other Mediterranean pine species with serotinous cones

Computational Schemes for Optimizing Domains of Attraction in Dynamical Systems

In this paper, several computational schemes are presented for the optimal tuning of the global behavior of nonlinear dynamical sys- tems. Specifically, the maximization of the size of domains of attraction associated with invariants in parametrized dynamical sys- tems is addressed. Cell Mapping (CM) tech- niques are used to estimate the size of the domains, and such size is then maximized via different optimization tools. First, a ge- netic algorithm is tested whose performance shows to be good for determining global maxima at the expense of high computa- tional cost. Secondly, an iterative scheme based on a Stochastic Approximation proce- dure (the Kiefer-Wolfowitz algorithm) is eval- uated showing acceptable performance at low cost. Finally, several schemes combining neu- ral network based estimations and optimiza- tion procedures are addressed with promising results. The performance of the methods is illus- trated with two applications: first on the well-known van der Pol equation with stan- dard parametrization, and second the tuning of a controller for saturated systems.

Local effects of depth-dependent water content of ice and snow and firn layers temperature on a conjectured subglacial lake below Amundsenisen Icefield (Svalbard)

It is known that the Amundsenisen Icefield in Southern Spitzbergen (Svalbard achipelago) is temperate with an upper layer of snow and firn. It is an accumulation area and, though ice/water mass balance is clearly subject to time evolution, observation data on the long-term elevation changes over the past 40 years (Nuth et al., 2010) allow to assume constant icefield surface. Within our study of the plausibility of a subglacial lake (Glowacki et al., 2007), here, we focus on the sensitivity of the system to the thermal effect of the firn and snow layers.

One or two poles of attraction in the international technological cooperation process?

In recent years, international cooperation processes have become a key mechanism for companies to internationalise their innovative activities, par ticularly in the case of small businesses whose size reduces their possibilities of developing internationalisation strategies autonomously in the same way as larger companies. In Spain, the existence of two parallel programmes with similar structures oriented towards Europe (EUREKA) and Latin America (IBEROEKA) raises the question as to whether the fact that companies participate in only one (unipolar) or both (bipolar) of these programmes is the result of a selection process, which, in turn, results in the existence of different collectives with different efficiency parameters. The aim of this study is to provide a comparative analysis based on the final reports of Spanish companies that have participated in the EUREKA programme. Two groups of companies were compared: one comprising companies that have only had international experience in Europe (EUREKA); and another formed by companies that have also carried out IBEROEKA projects. The conclusions confirm that the behaviour of both groups of companies differs substantially and reveal the importance of geographical perspective in the analysis of international cooperation in technology. This disparate behaviour is a relevant aspect that must be taken into account when designing policies to promote international technological cooperation.

Local experiences of liberal peace : marketization and emergent conflict dynamics in Sierra Leone

Peer reviewed

Termination of Ca2+ release by a local inactivation of ryanodine receptors in cardiac myocytes

In heart, a robust regulatory mechanism is required to counteract the regenerative Ca2+-induced Ca2+ release from the sarcoplasmic reticulum. Several mechanisms, including inactivation, adaptation, and stochastic closing of ryanodine receptors (RyRs) have been proposed, but no conclusive evidence has yet been provided. We probed the termination process of Ca2+ release by using a technique of imaging local Ca2+ release, or “Ca2+ spikes”, at subcellular sites; and we tracked the kinetics of Ca2+ release triggered by L-type Ca2+ channels. At 0 mV, Ca2+ release occurred and terminated within 40 ms after the onset of clamp pulses (0 mV). Increasing the open-duration and promoting the reopenings of Ca2+ channels with the Ca2+ channel agonist, FPL64176, did not prolong or trigger secondary Ca2+ spikes, even though two-thirds of the sarcoplasmic reticulum Ca2+ remained available for release. Latency of Ca2+ spikes coincided with the first openings but not with the reopenings of L-type Ca2+ channels. After an initial maximal release, even a multi-fold increase in unitary Ca2+ current induced by a hyperpolarization to −120 mV failed to trigger additional release, indicating absolute refractoriness of RyRs. When the release was submaximal (e.g., at +30 mV), tail currents did activate additional Ca2+ spikes; confocal images revealed that they originated from RyRs unfired during depolarization. These results indicate that Ca2+ release is terminated primarily by a highly localized, use-dependent inactivation of RyRs but not by the stochastic closing or adaptation of RyRs in intact ventricular myocytes.

Rapid, local adaptation of zooplankton behavior to changes in predation pressure in the absence of neutral genetic changes

Organisms producing resting stages provide unique opportunities for reconstructing the genetic history of natural populations. Diapausing seeds and eggs often are preserved in large numbers, representing entire populations captured in an evolutionary inert state for decades and even centuries. Starting from a natural resting egg bank of the waterflea Daphnia, we compare the evolutionary rates of change in an adaptive quantitative trait with those in selectively neutral DNA markers, thus effectively testing whether the observed genetic changes in the quantitative trait are driven by natural selection. The population studied experienced variable and well documented levels of fish predation over the past 30 years and shows correlated genetic changes in phototactic behavior, a predator-avoidance trait that is related to diel vertical migration. The changes mainly involve an increased plasticity response upon exposure to predator kairomone, the direction of the changes being in agreement with the hypothesis of adaptive evolution. Genetic differentiation through time was an order of magnitude higher for the studied behavioral trait than for neutral markers (DNA microsatellites), providing strong evidence that natural selection was the driving force behind the observed, rapid, evolutionary changes.

Global and local implications of biotechnology and climate change for future food supplies

The development of improved technology for agricultural production and its diffusion to farmers is a process requiring investment and time. A large number of studies of this process have been undertaken. The findings of these studies have been incorporated into a quantitative policy model projecting supplies of commodities (in terms of area and crop yields), equilibrium prices, and international trade volumes to the year 2020. These projections show that a “global food crisis,” as would be manifested in high commodity prices, is unlikely to occur. The same projections show, however, that in many countries, “local food crisis,” as manifested in low agricultural incomes and associated low food consumption in the presence of low food prices, will occur. Simulations show that delays in the diffusion of modern biotechnology research capabilities to developing countries will exacerbate local food crises. Similarly, global climate change will also exacerbate these crises, accentuating the importance of bringing strengthened research capabilities to developing countries.

Local translation of classes of mRNAs that are targeted to neuronal dendrites

The functioning of the neuronal dendrite results from a variety of biological processes including mRNA transport to and protein translation in the dendrite. The complexity of the mRNA population in dendrites suggests that specific biological processes are modulated through the regulation of dendritic biology. There are various classes of mRNAs in dendrites whose translation modulates the ability of the dendrite to receive and integrate presynaptic information. Among these mRNAs are those encoding selective transcription factors that function in the neuronal soma and ionotropic glutamate receptors that function on the neuronal membrane. Conclusive evidence that these mRNAs can be translated is reviewed, and identification of the endogenous sites of translation in living dendrites is presented. These data, as well as those described in the other articles resulting from this colloquium, highlight the complexity of dendritic molecular biology and the exquisitely selective and sensitive modulatory role played by the dendrite in facilitating intracellular and intercellular communication.