354 research outputs found

    An effective genetic algorithm for the minimum-label spanning tree problem

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    Given a connected, undirected graph G with labeled edges, the minimum-label spanning tree problem seeks a spanning tree on G to whose edges are attached the smallest possible number of labels. A greedy heuristic for this NP-hard prob-lem greedily chooses labels so as to reduce the number of components in the subgraphs they induce as quickly as possi-ble. A genetic algorithm for the problem encodes candidate solutions as permutations of the labels; an initial segment of such a chromosome lists the labels that appear on the edges in the chromosome's tree. Three versions of the GA apply generic or heuristic crossover and mutation operators and a local search step. In tests on 27 randomly-generated instances of the minimum-label spanning tree problem, ver-sions of the GA that apply generic operators, with and with-out the local search step, perform less well than the greedy heuristic, but a version that applies the local search step and operators tailored to the problem returns solutions that require on average 10 % fewer labels than the heuristic's

    The N=28 shell closure; from N=Z to the neutron drip line

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    The evolution of the N=28 neutron shell closure is studied in the N=28 isotones from neutron drip line's 40^{40}Mg to N=Z doubly magic 56^{56}Ni. It is found that the N=28 closure vanishes at Z=12 in favor of a deformed ground state. For Z=14 and Z=16 closed shell and intruder configurations are almost degenerate, leading to highly mixed ground states and to very low lying excited 0+^+ states. For Z>>20 the intruder states are always above the closed shell ground states. We examine their structure and their possible existence as collective yrare bands of well defined particle-hole character

    Novel Data Acquisition System for Silicon Tracking Detectors

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    We have developed a novel data acquisition system for measuring tracking parameters of a silicon detector in a particle beam. The system is based on a commercial Analog-to-Digital VME module and a PC Linux based Data Acquisition System. This DAQ is realized with C++ code using object-oriented techniques. Track parameters for the beam particles were reconstructed using off-line analysis code and automatic detector position alignment algorithm. The new DAQ was used to test novel Czochralski type silicon detectors. The important silicon detector parameters, including signal size distributions and signal to noise distributions, were successfully extracted from the detector under study. The efficiency of the detector was measured to be 95 %, the resolution about 10 micrometers, and the signal to noise ratio about 10.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics (CHEP03), La Jolla, Ca, USA, March 2003, 6 pages, LaTeX, 5 eps figures. PSN TUGP00

    Magnetic dipole probes of the sd and pf shell crossing in the A=36,38 argon isotopes

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    We have calculated the M1 strength distributions in the A=36,38 argon isotopes within large-scale shell model studies which consider valence nucleons in the sd and pf shells. While the M1 strength in 36Ar is well reproduced within the sd shell, the experimentally observed strong fragmentation of the M1 strength in 38Ar requires configuration mixing between the sd and the pf shells adding to our understanding of correlations across the N=20 shell gap.Comment: 14 pages, 8 figure

    Multiple components of PKA and TGF-beta pathways are mutated in pseudomyxoma peritonei

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    Pseudomyxoma peritonei (PMP) is a subtype of mucinous adenocarcinoma mainly restricted to the peritoneal cavity and most commonly originating from the appendix. The genetic background of PMP is poorly understood and no targeted treatments are currently available for this fatal disease. While RAS signaling pathway is affected in most if not all PMP cases and over half of them also have a mutation in the GNAS gene, other genetic alterations and affected pathways are, to a large degree, poorly known. In this study, we sequenced whole coding genome of nine PMP tumors and paired normal tissues in order to identify additional, commonly mutated genes and signaling pathways affected in PMP. These exome sequencing results were validated with an ultra-deep amplicon sequencing method, leading to 14 validated variants. The validated results contain seven genes that contribute to the protein kinase A (PKA) pathway. PKA pathway, which also contains GNAS, is a major player of overproduction of mucin, which is the characteristic feature of PMP. In addition to PKA pathway, we identified mutations in six genes that belong to the transforming growth factor beta (TGF-beta) pathway, which is a key regulator of cell proliferation. Since either GNAS mutation or an alternative mutation in the PKA pathway was identified in 8/9 patients, inhibition of the PKA pathway might reduce mucin production in most of the PMP patients and potentially suppress disease progression.Peer reviewe

    Spectroscopy of 34,35Si^{34,35}Si by β\beta decay: sd-fp shell gap and single-particle states

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    The 34,35Alβ^{34,35}Al\beta decays were studied at the CERN on-line mass separator ISOLDE by βγ,βγγ\beta-\gamma, \beta-\gamma-\gamma and βnγ\beta-n-\gamma measurements, in order to corroborate thelow-level description of 34Si^{34}Si and to obtain the first information on the level structure of the N=21 isotope 35Si^{35}Si. Earlier observed γ\gamma lines in 34Al^{34} Al decay were confirmed and new gamma transitions following both beta decay and β\beta-delayed neutron emission were established. The first level scheme in 35Si^{35}Si, including three excited states at 910, 974 and 2168 keV, is consistent with Jπ=3/2J^{\pi} =3/2^{-} and 3/2+3/2^{+} for the first two states respectively. Beta-decay half-life of T1/2=38.6(4)T_{1/2} = 38.6 (4) ms and beta-delayed neutron branching PnP_{n} value (Pn=41(13)(P_{n} =41(13) %) were measured unambiguously. The significance of the single-particle energy determination at N=21, Z=14, for assessing the effective interaction in sd-fp shell-model calculations, is discussed and illustrated by predictions for different n-rich isotopes

    [Formula Presented] decay of neutron-rich [Formula Presented] and [Formula Presented] isotopes

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    [Formula Presented] decays of on-line mass-separated neutron-rich [Formula Presented] and [Formula Presented] isotopes have been studied by using [Formula Presented] and [Formula Presented] coincidence spectroscopy. Extended decay schemes to the [Formula Presented] daughter nuclei have been constructed. The three-phonon quintuplet in [Formula Presented] is completed by including a new level at 2023.0 keV, which is tentatively assigned the spin and parity of [Formula Presented] The intruder band in [Formula Presented] is proposed up to the [Formula Presented] level at 2322.4 keV. The measured [Formula Presented]-decay half-life for the high-spin isomer of [Formula Presented] is [Formula Presented] Candidates for the three-phonon states, as well as the lowest members of the intruder band in [Formula Presented] are also presented. These data support the coexistence of quadrupole anharmonic vibration and proton particle-hole intruder excitations in [Formula Presented].</p

    The Evolution of Bat Vestibular Systems in the Face of Potential Antagonistic Selection Pressures for Flight and Echolocation

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    PMCID: PMC3634842This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

    Gene fusions and oncogenic mutations in MLH1 deficient and BRAFV600E wild-type colorectal cancers

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    Gene fusions can act as oncogenic drivers and offer targets for cancer therapy. Since fusions are rare in colorectal cancer (CRC), their universal screening seems impractical. Our aim was to investigate gene fusions in 62 CRC cases with deficient MLH1 (dMLH1) and BRAFV600E wild-type (wt) status from a consecutive real-life series of 2079 CRCs. First, gene fusions were analysed using a novel FusionPlex Lung v2 RNA-based next-generation sequencing (NGS) panel, and these results were compared to a novel Idylla GeneFusion assay and pan-TRK immunohistochemistry (IHC). NGS detected seven (7/62, 11%) NTRK1 fusions (TPM3::NTRK1, PLEKHA6::NTRK1 and LMNA::NTRK1, each in two cases, and IRF2BP2::NTRK1 in one case). In addition, two ALK, four RET and seven BRAF fusions were identified. Idylla detected seven NTRK1 expression imbalances, in line with the NGS results (overall agreement 100%). Furthermore, Idylla detected the two NGS-identified ALK rearrangements as one specific ALK fusion and one ALK expression imbalance, whilst only two of the four RET fusions were discovered. However, Idylla detected several expression imbalances of ALK (n = 7) and RET (n = 1) that were found to be fusion negative with the NGS. Pan-TRK IHC showed clearly detectable, fusion partner-dependent staining patterns in the seven NTRK1 fusion cases. Overall agreement for pan-TRK antibody clone EPR17341 was 98% and for A7H6R 100% when compared to the NGS. Of the 62 CRCs, 43 were MLH1 promoter hypermethylated (MLH1ph) and 39 were RASwt. All fusion cases were both MLH1ph and RASwt. Our results show that kinase fusions (20/30, 67%) and most importantly targetable NTRK1 fusions (7/30, 23%) are frequent in CRCs with dMLH1/BRAFV600Ewt/MLH1ph/RASwt. NGS was the most comprehensive method in finding the fusions, of which a subset can be screened by Idylla or IHC, provided that the result is confirmed by NGS

    What we talk about when we talk about "global mindset": managerial cognition in multinational corporations

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    Recent developments in the global economy and in multinational corporations have placed significant emphasis on the cognitive orientations of managers, giving rise to a number of concepts such as “global mindset” that are presumed to be associated with the effective management of multinational corporations (MNCs). This paper reviews the literature on global mindset and clarifies some of the conceptual confusion surrounding the construct. We identify common themes across writers, suggesting that the majority of studies fall into one of three research perspectives: cultural, strategic, and multidimensional. We also identify two constructs from the social sciences that underlie the perspectives found in the literature: cosmopolitanism and cognitive complexity and use these two constructs to develop an integrative theoretical framework of global mindset. We then provide a critical assessment of the field of global mindset and suggest directions for future theoretical and empirical research
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