5,044 research outputs found
Integrating data from vessel monitoring system and fish landings in Menditerranean small fleets, using a PostgreSQL database with PostGIS extension
Geospatial technologies represent an advance in knowledge of marine
ecosystems, allowing approach the study of the potential effect of world fishing
fleets and their dynamics. Nevertheless, their application to fisheries biology is very
recent and its use is generalizing when the ICES (International Council for the Exploration
of the Sea) proposed one methodology to study fisheries and their impact
in Atlantic Ocean ecosystems in the 2008 year. This procedure is based on the use
of position data from the "blue boxes" (VMS-Vessel Monitoring System), mandatory
since 2006 due to a European regulation, and it's present in most fishing boats.
The junction of the VMS, fishing logbooks and landings data enables us to obtain
among others results, maps of fishing effort, behaviour of fishing fleet and precise
location of fishing grounds at the European waters. However, its design is made for
large trawlers and longliners, and extensive Atlantic areas. This fact makes impossible
its application for the study of the fleet and fisheries in Mediterranean waters.
Because, the boats are much smaller, have lower mobility and they work in small
fishing areas. The aim of this work has been to develop and apply a methodology
(ICES based) to study fishing effort on species of commercial interest in Catalan
coast, using scripting PL/SQL procedures of PostgreSQL system database with Post-
GIS extension.Peer Reviewe
Nociceptive-Evoked Potentials Are Sensitive to Behaviorally Relevant Stimulus Displacements in Egocentric Coordinates.
Feature selection has been extensively studied in the context of goal-directed behavior, where it is heavily driven by top-down factors. A more primitive version of this function is the detection of bottom-up changes in stimulus features in the environment. Indeed, the nervous system is tuned to detect fast-rising, intense stimuli that are likely to reflect threats, such as nociceptive somatosensory stimuli. These stimuli elicit large brain potentials maximal at the scalp vertex. When elicited by nociceptive laser stimuli, these responses are labeled laser-evoked potentials (LEPs). Although it has been shown that changes in stimulus modality and increases in stimulus intensity evoke large LEPs, it has yet to be determined whether stimulus displacements affect the amplitude of the main LEP waves (N1, N2, and P2). Here, in three experiments, we identified a set of rules that the human nervous system obeys to identify changes in the spatial location of a nociceptive stimulus. We showed that the N2 wave is sensitive to: (1) large displacements between consecutive stimuli in egocentric, but not somatotopic coordinates; and (2) displacements that entail a behaviorally relevant change in the stimulus location. These findings indicate that nociceptive-evoked vertex potentials are sensitive to behaviorally relevant changes in the location of a nociceptive stimulus with respect to the body, and that the hand is a particularly behaviorally important site
Approximating open quantum system dynamics in a controlled and efficient way: A microscopic approach to decoherence
We demonstrate that the dynamics of an open quantum system can be calculated
efficiently and with predefined error, provided a basis exists in which the
system-environment interactions are local and hence obey the Lieb-Robinson
bound. We show that this assumption can generally be made. Defining a dynamical
renormalization group transformation, we obtain an effective Hamiltonian for
the full system plus environment that comprises only those environmental
degrees of freedom that are within the effective light cone of the system. The
reduced system dynamics can therefore be simulated with a computational effort
that scales at most polynomially in the interaction time and the size of the
effective light cone. Our results hold for generic environments consisting of
either discrete or continuous degrees of freedom
Squeezing out predictions with leptogenesis from SO(10)
We consider the see-saw mechanism within a non-supersymmetric SO(10) model.
By assuming the SO(10) quark-lepton symmetry, and after imposing suitable
conditions that ensure that the right-handed (RH) neutrino masses are at most
mildly hierarchical (compact RH spectrum) we obtain a surprisingly predictive
scenario. The absolute neutrino mass scale, the Dirac and the two Majorana
phases of the neutrino mixing matrix remain determined in terms of the set of
already measured low energy observables, modulo a discrete ambiguity in the
signs of two neutrino mixing angles and of the Dirac phase. The RH neutrinos
mass spectrum is also predicted, as well as the size and sign of the
leptogenesis CP asymmetries. We compute the cosmological baryon asymmetry
generated through leptogenesis and obtain the correct sign and a size
compatible with observations.Comment: 18 pages, 2 figures; minor changes, version accepted for publication
in PR
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Spontaneous Embedding of DNA Mismatches Within the RNA:DNA Hybrid of CRISPR-Cas9.
CRISPR-Cas9 is the forefront technology for editing the genome. In this system, the Cas9 protein is programmed with guide RNAs to process DNA sequences that match the guide RNA forming an RNA:DNA hybrid structure. However, the binding of DNA sequences that do not fully match the guide RNA can limit the applicability of CRISPR-Cas9 for genome editing, resulting in the so-called off-target effects. Here, molecular dynamics is used to probe the effect of DNA base pair mismatches within the RNA:DNA hybrid in CRISPR-Cas9. Molecular simulations revealed that the presence of mismatched pairs in the DNA at distal sites with respect to the Protospacer Adjacent Motif (PAM) recognition sequence induces an extended opening of the RNA:DNA hybrid, leading to novel interactions established by the unwound nucleic acids and the protein counterpart. On the contrary, mismatched pairs upstream of the RNA:DNA hybrid are rapidly incorporated within the heteroduplex, with minor effect on the protein-nucleic acid interactions. As a result, mismatched pairs at PAM distal ends interfere with the activation of the catalytic HNH domain, while mismatches fully embedded in the RNA:DNA do not affect the HNH dynamics and enable its activation to cleave the DNA. These findings provide a mechanistic understanding to the intriguing experimental evidence that PAM distal mismatches hamper a proper function of HNH, explaining also why mismatches within the heteroduplex are much more tolerated. This constitutes a step forward in understanding off-target effects in CRISPR-Cas9, which encourages novel structure-based engineering efforts aimed at preventing the onset of off-target effects
N-acetylcysteine serves as substrate of 3-mercaptopyruvate sulfurtransferase and stimulates sulfide metabolism in colon cancer cells
Hydrogen sulfide (H2S) is an endogenously produced signaling molecule. The enzymes 3-mercaptopyruvate sulfurtransferase (MST), partly localized in mitochondria, and the inner mitochondrial membrane-associated sulfide:quinone oxidoreductase (SQR), besides being respectively involved in the synthesis and catabolism of H2S, generate sulfane sulfur species such as persulfides and polysulfides, currently recognized as mediating some of the H2S biological effects. Reprogramming of H2S metabolism was reported to support cellular proliferation and energy metabolism in cancer cells. As oxidative stress is a cancer hallmark and N-acetylcysteine (NAC) was recently suggested to act as an antioxidant by increasing intracellular levels of sulfane sulfur species, here we evaluated the effect of prolonged exposure to NAC on the H2S metabolism of SW480 colon cancer cells. Cells exposed to NAC for 24 h displayed increased expression and activity of MST and SQR. Furthermore, NAC was shown to: (i) persist at detectable levels inside the cells exposed to the drug for up to 24 h and (ii) sustain H2S synthesis by human MST more effectively than cysteine, as shown working on the isolated recombinant enzyme. We conclude that prolonged exposure of colon cancer cells to NAC stimulates H2S metabolism and that NAC can serve as a substrate for human MST
Batching of Tasks by Users of Pseudonymous Forums: Anonymity Compromise and Protection
There are a number of forums where people participate under pseudonyms. One
example is peer review, where the identity of reviewers for any paper is
confidential. When participating in these forums, people frequently engage in
"batching": executing multiple related tasks (e.g., commenting on multiple
papers) at nearly the same time. Our empirical analysis shows that batching is
common in two applications we consider \unicode{x2013} peer review and
Wikipedia edits. In this paper, we identify and address the risk of
deanonymization arising from linking batched tasks. To protect against linkage
attacks, we take the approach of adding delay to the posting time of batched
tasks. We first show that under some natural assumptions, no delay mechanism
can provide a meaningful differential privacy guarantee. We therefore propose a
"one-sided" formulation of differential privacy for protecting against linkage
attacks. We design a mechanism that adds zero-inflated uniform delay to events
and show it can preserve privacy. We prove that this noise distribution is in
fact optimal in minimizing expected delay among mechanisms adding independent
noise to each event, thereby establishing the Pareto frontier of the trade-off
between the expected delay for batched and unbatched events. Finally, we
conduct a series of experiments on Wikipedia and Bitcoin data that corroborate
the practical utility of our algorithm in obfuscating batching without
introducing onerous delay to a system
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