2,253 research outputs found

    Tortugas marinas en aguas argentinas

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    Con la ayuda de los sensores remotos y los sistemas de posicionamiento geográfico, los científicos están descubriendo varias facetas sobre las vida de las tortugas marinas. Se describe el método para realizar el siguimiento satelital, sus migraciones, y se dan las características de las especies de tortugas marinas encontradas en aguas costeras de la Argentina. Este trabajo de divulgación científica hace hincapié en la importancia de su conservación, según la Unión Internacional para la Conservación de la Naturaleza, éstas se encuentran en peligro o en peligro crítico de extinción en todo el mundo. Se incluyen al final otras lecturas sugeridas sobre el tema

    An Approach to Model Resources Rationalisation in Hybrid Clouds through Users Activity Characterisation

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    In recent years, some strategies (e.g., server consolidation by means of virtualisation techniques) helped the managers of large Information Technology (IT) infrastructures to limit, when possible, the use of hardware resources in order to provide reliable services and to reduce the Total Cost of Ownership (TCO) of such infrastructures. Moreover, with the advent of Cloud computing, a resource usage rationalisation can be pursued also for the users applications, if this is compatible with the Quality of Service (QoS) which must be guaranteed. In this perspective, modern datacenters are “elastic”, i.e., able to shrink or enlarge the number of local physical or virtual resources from private/public Clouds. Moreover, many of large computing environments are integrated in distributed computing environment as the grid and cloud infrastructures. In this document, we report some advances in the realisation of a utility, we named Adaptive Scheduling Controller (ASC) which, interacting with the datacenter resource manager, allows an effective and efficient usage of resources, also by means of users jobs classification. Here, we focus both on some data mining algorithms which allows to classify the users activity and on the mathematical formalisation of the functional used by ASC to find the most suitable configuration for the datacenter’s resource manager. The presented case study concerns the SCoPE infrastructure, which has a twofold role: local computing resources provider for the University of Naples Federico II and remote resources provider for both the Italian Grid Infrastructure (IGI) and the European Grid Infrastructure (EGI) Federated Cloud

    The presence of cortical neurons in striatal-cortical co-cultures alters the effects of dopamine and BDNF on medium spiny neuron dendritic development

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    Medium spiny neurons (MSNs) are the major striatal neuron and receive synaptic input from both glutamatergic and dopaminergic afferents. These synapses are made on MSN dendritic spines, which undergo density and morphology changes in association with numerous disease and experience-dependent states. Despite wide interest in the structure and function of mature MSNs, relatively little is known about MSN development. Furthermore, most in vitro studies of MSN development have been done in simple striatal cultures that lack any type of non-autologous synaptic input, leaving open the question of how MSN development is affected by a complex environment that includes other types of neurons, glia, and accompanying secreted and cell-associated cues. Here we characterize the development of MSNs in striatal-cortical co-culture, including quantitative morphological analysis of dendritic arborization and spine development, describing progressive changes in density and morphology of developing spines. Overall, MSN growth is much more robust in the striatal-cortical co-culture compared to striatal mono-culture. Inclusion of dopamine (DA) in the co-culture further enhances MSN dendritic arborization and spine density, but the effects of DA on dendritic branching are only significant at later times in development. In contrast, exogenous Brain Derived Neurotrophic Factor (BDNF) has only a minimal effect on MSN development in the co-culture, but significantly enhances MSN dendritic arborization in striatal mono-culture. Importantly, inhibition of NMDA receptors in the co-culture significantly enhances the effect of exogenous BDNF, suggesting that the efficacy of BDNF depends on the cellular environment. Combined, these studies identify specific periods of MSN development that may be particularly sensitive to perturbation by external factors and demonstrate the importance of studying MSN development in a complex signaling environment

    On the action potential as a propagating density pulse and the role of anesthetics

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    The Hodgkin-Huxley model of nerve pulse propagation relies on ion currents through specific resistors called ion channels. We discuss a number of classical thermodynamic findings on nerves that are not contained in this classical theory. Particularly striking is the finding of reversible heat changes, thickness and phase changes of the membrane during the action potential. Data on various nerves rather suggest that a reversible density pulse accompanies the action potential of nerves. Here, we attempted to explain these phenomena by propagating solitons that depend on the presence of cooperative phase transitions in the nerve membrane. These transitions are, however, strongly influenced by the presence of anesthetics. Therefore, the thermodynamic theory of nerve pulses suggests a explanation for the famous Meyer-Overton rule that states that the critical anesthetic dose is linearly related to the solubility of the drug in the membranes.Comment: 13 pages, 8 figure

    Synthesis, biophysical characterization and anti-HIV activity of d(TG3AG) Quadruplexes bearing hydrophobic tails at the 5'-end

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    Novel conjugated G-quadruplex-forming d(TG3AG) oligonucleotides, linked to hydrophobic groups through phosphodiester bonds at 50-end, have been synthesized as potential anti-HIV aptamers, via a fully automated, online phosphoramidite-based solid-phase strategy. Conjugated quadruplexes showed pronounced anti-HIV activity with some preference for HIV-1, with inhibitory activity invariably in the low micromolar range. The CD and DSC monitored thermal denaturation studies on the resulting quadruplexes, indicated the insertion of lipophilic residue at the 50-end, conferring always improved stability to the quadruplex complex (20 < DTm < 40 C). The data suggest no direct functional relationship between the thermal stability and anti-HIV activity of the folded conjugated G-quartets. It would appear that the nature of the residue at 50 end of the d(TG3AG) quadruplexes plays an important role in the thermodynamic stabilization but a minor influence on the anti-HIV activity. Moreover, a detailed CD and DSC analyses indicate a monophasic behaviour for sequences I and V, while for ODNs (II–IV) clearly show that these quadruplex structures deviate from simple two-state melting, supporting the hypothesis that intermediate states along the dissociation pathway may exis

    Astrophysically Triggered Searches for Gravitational Waves: Status and Prospects

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    In gravitational-wave detection, special emphasis is put onto searches that focus on cosmic events detected by other types of astrophysical observatories. The astrophysical triggers, e.g. from gamma-ray and X-ray satellites, optical telescopes and neutrino observatories, provide a trigger time for analyzing gravitational wave data coincident with the event. In certain cases the expected frequency range, source energetics, directional and progenitor information is also available. Beyond allowing the recognition of gravitational waveforms with amplitudes closer to the noise floor of the detector, these triggered searches should also lead to rich science results even before the onset of Advanced LIGO. In this paper we provide a broad review of LIGO's astrophysically triggered searches and the sources they target

    Sensitivity to Gravitational Waves from Compact Binary Coalescences Achieved during LIGO's Fifth and Virgo's First Science Run

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    We summarize the sensitivity achieved by the LIGO and Virgo gravitational wave detectors for compact binary coalescence (CBC) searches during LIGO's fifth science run and Virgo's first science run. We present noise spectral density curves for each of the four detectors that operated during these science runs which are representative of the typical performance achieved by the detectors for CBC searches. These spectra are intended for release to the public as a summary of detector performance for CBC searches during these science runs.Comment: 12 pages, 5 figure

    A BIOMECHANICAL AND PHYSIOLOGICAL COMPARISON OF OLYMPIC FLATWATER CANOEING

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    Simulation of sporting activities for the purpose of assessing physiological parameters and for conditioning athletes has been an important development within the sports world. The purpose of this study was to compare Olympic flatwater canoeing technique to that of an ergometer developed by Pyke et al. at Dalhousie University. The comparison, using three national team members, was both physiological and biomechanical in order to determine; 1) if accurate physiological measurements focusing on the upper body during racing conditions could be matched while using the laboratory ergometer; 2) if the ergometer movement patterns closely approximated the actual on-water racing stroke. The results indicated that the techniques were similar physiologically and different biomechanically. VE and VO2 max, for the 500 m. race and for a simulated 500 m. trial were close and consistent across all S's. Results for the 1000 m. were acceptable, but not as accurate as the 500 m. The use of the Pyke ergometer was judged on the whole to be a valid physiological testing procedure. The major difficulty with the ergometer was that it forced all S's to alter their racing strokes in order to successfully maintain movement of the mechanism. Changes in movement and velocity patterns of the trunk, arms and hands of all S's were considerable and led to the conclusion that this ergometer, in its original design, not be used as a training device

    Integrating Spatial Data Infrastructures (SDIs) with Volunteered Geographic Information (VGI) creating a Global GIS platform

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    Spatial Data Infrastructures (SDIs) are a special category of data hubs that involve technological and human resources and follow well defined legal and technical procedures to collect, store, manage and distribute spatial data. INSPIRE is the EU’s authoritative SDI in which each Member State provides access to their spatial data across a wide spectrum of data themes to support policy-making. In contrast, Volunteered Geographic Information (VGI) is one type of user-generated geographic information (GI) where volunteers use the web and mobile devices to create, assemble and disseminate spatial information. There are similarities and differences between SDIs and VGI, as well as advantages and disadvantages to both. Thus, the integration of these two data sources will enhance what is offered to end users to facilitate decision-making. This idea of integration is in its early stages, because several key issues need to be considered and resolved first. Therefore, this chapter discusses the challenges of integrating VGI with INSPIRE and outlines a generic framework for a global integrated GIS platform, similar in concept to Digital Earth and Virtual Geographic Environments (VGEs), as a realistic scenario for advancements in the short term
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