339 research outputs found
GSTP1 Polymorphisms Sex-Specific Association with Cognitive Outcomes in Survivors of Pediatric Medulloblastoma Tumors
This study investigated specific single nucleotide polymorphisms (SNPs) and their association with attentional deficits and hippocampal volume in survivors of medulloblastoma brain tumors. The sample with neuropsychological assessment includes eighteen medulloblastoma survivors and eighteen age-and-sex-matched healthy controls. We hypothesized that medulloblastoma survivors with a GSTP1 polymorphism will have significantly greater deficits in attention span and smaller bilateral hippocampal volumes compared to survivors without a polymorphism and healthy controls. We did not establish the specificity of hippocampal volume loss, and our sample may have more global subcortical morphological alterations. When separating groups by sex, we found large effect sizes between males with a GSTP1 polymorphism and females with a GSTP1 polymorphism across measures of attention span, working memory span and processing speed. Females with a polymorphism performed significantly worse than females without a polymorphism on full-scale intelligence quotient (IQ) and verbal IQ. Sex-specific genetic risk may explain part of the variability in long-term cognitive outcomes for medulloblastoma survivors
Observational Constraints to the Evolution of Massive Stars
We consider some aspects of the evolution of massive stars which can only be
elucidated by means of "indirect" observations, i.e. measurements of the
effects of massive stars on their environments. We discuss in detail the early
evolution of massive stars formed in high metallicity regions as inferred from
studies of HII regions in external galaxies.Comment: 6 pages, 1 figure; Invited Paper presented at the Roma-Trieste
Workshop 1999 "The Chemical Evolution of the Milky Way: Stars versus
Clusters", Vulcano Island (ME, Italy), 20-24 September, 1999, eds. F.
Giovannelli & F. Matteucci, Kluwer-Holland (in press
Optimization of Energy-Efficient Cluster Head Selection Algorithm for Internet of Things in Wireless Sensor Networks
The Internet of Things (IoT) now uses the Wireless Sensor Network (WSN) as a platform to sense and communicate data. The increase in the number of embedded and interconnected devices on the Internet has resulted in a need for software solutions to manage them proficiently in an elegant and scalable manner. Also, these devices can generate massive amounts of data, resulting in a classic Big Data problem that must be stored and processed. Large volumes of information have to be produced by using IoT applications, thus raising two major issues in big data analytics. To ensure an efficient form of mining of both spatial and temporal data, a sensed sample has to be collected. So for this work, a new strategy to remove redundancy has been proposed. This classifies all forms of collected data to be either relevant or irrelevant in choosing suitable information even before they are forwarded to the base station or the cluster head. A Low-Energy Adaptive Clustering Hierarchy (LEACH) is a cluster-based routing protocol that uses cluster formation. The LEACH chooses one head from the network sensor nodes, such as the Cluster Head (CH), to rotate the role to a new distributed energy load. The CHs were chosen randomly with the possibility of all CHs being concentrated in one locality. The primary idea behind such dynamic clustering was them resulted in more overheads due to changes in the CH and advertisements. Therefore, the LEACH was not suitable for large networks. Here, Particle Swarm Optimization (PSO) and River Formation Dynamics are used to optimize the CH selection (RFD). The results proved that the proposed method to have performed better compared to other methods
Impact of pro-domain stability of matrix metalloproteinase-8 on the outcome of sepsis
Citation:
Berx, B., M. Dickey-Collas, M.D. Skogen, Y.-H. De Roeck, H. Klein, R. Barciela, R.M. Forster, E. Dombrowsky, M. Huret, M. Payne, Y. Sagarminaga, and C. Schrum. 2011. Does operational oceanography address the needs of fisheries and applied environmental scientists? Oceanography 24(1):166–171, doi:10.5670/oceanog.2011.14.Although many oceanographic data products are now considered
operational, continued dialogue between data producers and their user communities is still needed. The fisheries and environmental science communities have often been criticized for their lack of multidisciplinarity, and it is not clear whether recent developments in operational oceanographic products are addressing these needs. The International Council for the Exploration of the Sea (ICES) Working Group on Operational Oceanographic products for Fisheries and Environment (WGOOFE) identified a potential mismatch between user requirements and the perception of
requirements by the providers. Through a questionnaire (98 respondents), WGOOFE identified some of these issues. Although products of physical variables were in higher demand, several biological parameters scored in the top 10 rankings. Users placed
specific focus on historic time series products with monthly or annual resolution and updating on similar time scales. A significant percentage requested access to numerical data rather than graphical output. While the outcomes of this survey challenge our views of operational oceanography, several initiatives are already attempting to close the gap between user requirements and products available
Spin-coated thin films of metal porphyrin-phthalocyanine blend for an optochemical sensor of alcohol vapours
Abstract Organic thin films based on a blend of two types of metal-co-ordinated macromolecules, i.e. Zn(II) tetra-4-(2,4-di-tert-amylphenoxy)-phthalocyanine (ZnPc) and Cu(II) tetrakis(p-tert-butylphenyl)porphyrin (CuP) have been deposited by spin-coating and used as optical chemically interacting materials for the detection of methanol, ethanol and isopropanol vapours. This paper reports the use of a specific optical technique consisting of the selection of four specific spectral regions taken in the UV-Vis spectral range corresponding to the typical Q and Soret bands of the phthalocyanine and porphyrin macromolecules and their corresponding blends. The variations in the absorption peaks obtained by the exposure of the single ZnPc and CuP sensing layers to the considered vapours in controlled atmosphere have been analysed and compared with those derived from a thin film obtained by mixing the two metal complexes in an appropriate ratio. The performance of the heterogeneous sensing layer (i.e. ZnPc/CuP blend)-based sensor evaluated in term of response and selectivity is different from that of single homogeneous films
Characterization and Performance of PADME's Cherenkov-Based Small-Angle Calorimeter
The PADME experiment, at the Laboratori Nazionali di Frascati (LNF), in
Italy, will search for invisible decays of the hypothetical dark photon via the
process , where the escapes detection. The
dark photon mass range sensitivity in a first phase will be 1 to 24 MeV. We
report here on measurement and simulation studies of the performance of the
Small-Angle Calorimeter, a component of PADME's detector dedicated to rejecting
2- and 3-gamma backgrounds. The crucial requirement is a timing resolution of
less than 200 ps, which is satisfied by the choice of PbF crystals and the
newly released Hamamatsu R13478UV photomultiplier tubes (PMTs). We find a
timing resolution of 81 ps (with double-peak separation resolution of 1.8 ns)
and a single-crystal energy resolution of 5.7%/ with light yield of
2.07 photo-electrons per MeV, using 100 to 400 MeV electrons at the Beam Test
Facility of LNF. We also propose the investigation of a two-PMT solution
coupled to a single PbF crystal for higher-energy applications, which has
potentially attractive features.Comment: 12 pages, 19 figures. v2: added section on radiation damage studie
Disorder and Funneling Effects on Exciton Migration in Tree-Like Dendrimers
The center-bound excitonic diffusion on dendrimers subjected to several types
of non-homogeneous funneling potentials, is considered. We first study the
mean-first passage time (MFPT) for diffusion in a linear potential with
different types of correlated and uncorrelated random perturbations. Increasing
the funneling force, there is a transition from a phase in which the MFPT grows
exponentially with the number of generations , to one in which it does so
linearly. Overall the disorder slows down the diffusion, but the effect is much
more pronounced in the exponential compared to the linear phase. When the
disorder gives rise to uncorrelated random forces there is, in addition, a
transition as the temperature is lowered. This is a transition from a
high- regime in which all paths contribute to the MFPT to a low- regime
in which only a few of them do. We further explore the funneling within a
realistic non-linear potential for extended dendrimers in which the dependence
of the lowest excitonic energy level on the segment length was derived using
the Time-Dependent Hatree-Fock approximation. Under this potential the MFPT
grows initially linearly with but crosses-over, beyond a molecular-specific
and -dependent optimal size, to an exponential increase. Finally we consider
geometrical disorder in the form of a small concentration of long connections
as in the {\it small world} model. Beyond a critical concentration of
connections the MFPT decreases significantly and it changes to a power-law or
to a logarithmic scaling with , depending on the strength of the funneling
force.Comment: 13 pages, 9 figure
Excitonic Funneling in Extended Dendrimers with Non-Linear and Random Potentials
The mean first passage time (MFPT) for photoexcitations diffusion in a
funneling potential of artificial tree-like light-harvesting antennae
(phenylacetylene dendrimers with generation-dependent segment lengths) is
computed. Effects of the non-linearity of the realistic funneling potential and
slow random solvent fluctuations considerably slow down the center-bound
diffusion beyond a temperature-dependent optimal size. Diffusion on a
disordered Cayley tree with a linear potential is investigated analytically. At
low temperatures we predict a phase in which the MFPT is dominated by a few
paths.Comment: 4 pages, 4 figures, To be published in Phys. Rev. Let
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