260 research outputs found
An exploration of the impact of working individually versus working collectively on stress and performance
The purpose of the present study was to examine the impact of working alone versus working with others on stress and performance. Gender was also looked at as a variable affecting stress and performance as well. The Block by Block design, a building game consisting of seven different shaped blocks, was used in order to assess the ninety-five participants (23 male & 72 female) recruited from a medium sized university in southern New Jersey. Subjects were assigned to work either alone or with others in recreating specific images using the blocks, and were then asked to report their performance and individual stress. Analysis using the Mann-Whitney test revealed a significant effect found on performance by subject grouping
Crystal-field level inversion in lightly Mn-doped Sr3Ru2O7
Sr3(Ru1-xMnx)2O7, in which 4d-Ru is substituted by the more localized 3d-Mn,
is studied by x-ray dichroism and spin-resolved density functional theory. We
find that Mn impurities do not exhibit the same 4+ valence of Ru, but act as 3+
acceptors; the extra eg electron occupies the in-plane 3dx2-y2 orbital instead
of the expected out-of-plane 3d3z2-r2. We propose that the 3d-4d interplay, via
the ligand oxygen orbitals, is responsible for this crystal-field level
inversion and the material's transition to an antiferromagnetic, possibly
orbitally-ordered, low-temperature state.Comment: A high-resolution version can be found at
http://www.physics.ubc.ca/~quantmat/ARPES/PUBLICATIONS/Articles/MnSr3Ru2O7_XAS.pd
WARNING: Physics Envy May Be Hazardous To Your Wealth!
The quantitative aspirations of economists and financial analysts have for
many years been based on the belief that it should be possible to build models
of economic systems - and financial markets in particular - that are as
predictive as those in physics. While this perspective has led to a number of
important breakthroughs in economics, "physics envy" has also created a false
sense of mathematical precision in some cases. We speculate on the origins of
physics envy, and then describe an alternate perspective of economic behavior
based on a new taxonomy of uncertainty. We illustrate the relevance of this
taxonomy with two concrete examples: the classical harmonic oscillator with
some new twists that make physics look more like economics, and a quantitative
equity market-neutral strategy. We conclude by offering a new interpretation of
tail events, proposing an "uncertainty checklist" with which our taxonomy can
be implemented, and considering the role that quants played in the current
financial crisis.Comment: v3 adds 2 reference
Medulloblastoma Exome Sequencing Uncovers Subtype-Specific Somatic Mutations
Medulloblastomas are the most common malignant brain tumors in children1. Identifying and understanding the genetic events that drive these tumors is critical for the development of more effective diagnostic, prognostic and therapeutic strategies. Recently, our group and others described distinct molecular subtypes of medulloblastoma based on transcriptional and copy number profiles2–5. Here, we utilized whole exome hybrid capture and deep sequencing to identify somatic mutations across the coding regions of 92 primary medulloblastoma/normal pairs. Overall, medulloblastomas exhibit low mutation rates consistent with other pediatric tumors, with a median of 0.35 non-silent mutations per megabase. We identified twelve genes mutated at statistically significant frequencies, including previously known mutated genes in medulloblastoma such as CTNNB1, PTCH1, MLL2, SMARCA4 and TP53. Recurrent somatic mutations were identified in an RNA helicase gene, DDX3X, often concurrent with CTNNB1 mutations, and in the nuclear co-repressor (N-CoR) complex genes GPS2, BCOR, and LDB1, novel findings in medulloblastoma. We show that mutant DDX3X potentiates transactivation of a TCF promoter and enhances cell viability in combination with mutant but not wild type beta-catenin. Together, our study reveals the alteration of Wnt, Hedgehog, histone methyltransferase and now N-CoR pathways across medulloblastomas and within specific subtypes of this disease, and nominates the RNA helicase DDX3X as a component of pathogenic beta-catenin signaling in medulloblastoma
Aplicacao do kDNA-PCR para diagnostico de rotina de leishmaniose tegumentar americana em um hospital de referencia
SUMMARY This study evaluated the applicability of kDNA-PCR as a prospective routine diagnosis method for American tegumentary leishmaniasis (ATL) in patients from the Instituto de Infectologia Emílio Ribas (IIER), a reference center for infectious diseases in São Paulo - SP, Brazil. The kDNA-PCR method detected Leishmania DNA in 87.5% (112/128) of the clinically suspected ATL patients, while the traditional methods demonstrated the following percentages of positivity: 62.8% (49/78) for the Montenegro skin test, 61.8% (47/76) for direct investigation, and 19.3% (22/114) for in vitro culture. The molecular method was able to confirm the disease in samples considered negative or inconclusive by traditional laboratory methods, contributing to the final clinical diagnosis and therapy of ATL in this hospital. Thus, we strongly recommend the inclusion of kDNA-PCR amplification as an alternative diagnostic method for ATL, suggesting a new algorithm routine to be followed to help the diagnosis and treatment of ATL in IIER.RESUMO Este estudo avaliou a aplicabilidade do kDNA-PCR como método de rotina para diagnóstico de leishmaniose tegumentar americana (ATL) no Instituto de Infectologia Emílio Ribas (IIER), São Paulo, SP, Brasil. O método kDNA-PCR detectou DNA de Leishmania em 87,5% (112/128) dos pacientes com suspeita de ter leishmaniose e, os métodos tradicionais apresentaram as seguintes porcentagens de positividade: 62,8% (49/78) para o teste de Montenegro, 61,8% (47/76) para a pesquisa direta e 19,3% (22/114) para cultura in vitro. O método molecular confirmou a doença em amostras negativas ou inconclusivas pelos métodos laboratoriais tradicionais e, mostrou-se capaz de auxiliar na identificação de infecções causadas pela espécie Leishmania (V.) braziliensis. Além disso, a revisão dos prontuários médicos confirmou a importância do método PCR-RFLP no diagnóstico final de ATL, prognóstico e escolha do tratamento. Assim, recomendamos a inclusão do PCR como método diagnóstico de ATL na rotina hospitalar, e sugerimos um fluxograma para solicitação de exames laboratoriais
The RESET project: constructing a European tephra lattice for refined synchronisation of environmental and archaeological events during the last c. 100 ka
This paper introduces the aims and scope of the RESET project (. RESponse of humans to abrupt Environmental Transitions), a programme of research funded by the Natural Environment Research Council (UK) between 2008 and 2013; it also provides the context and rationale for papers included in a special volume of Quaternary Science Reviews that report some of the project's findings. RESET examined the chronological and correlation methods employed to establish causal links between the timing of abrupt environmental transitions (AETs) on the one hand, and of human dispersal and development on the other, with a focus on the Middle and Upper Palaeolithic periods. The period of interest is the Last Glacial cycle and the early Holocene (c. 100-8 ka), during which time a number of pronounced AETs occurred. A long-running topic of debate is the degree to which human history in Europe and the Mediterranean region during the Palaeolithic was shaped by these AETs, but this has proved difficult to assess because of poor dating control. In an attempt to move the science forward, RESET examined the potential that tephra isochrons, and in particular non-visible ash layers (cryptotephras), might offer for synchronising palaeo-records with a greater degree of finesse. New tephrostratigraphical data generated by the project augment previously-established tephra frameworks for the region, and underpin a more evolved tephra 'lattice' that links palaeo-records between Greenland, the European mainland, sub-marine sequences in the Mediterranean and North Africa. The paper also outlines the significance of other contributions to this special volume: collectively, these illustrate how the lattice was constructed, how it links with cognate tephra research in Europe and elsewhere, and how the evidence of tephra isochrons is beginning to challenge long-held views about the impacts of environmental change on humans during the Palaeolithic. © 2015 Elsevier Ltd.RESET was funded through Consortium Grants awarded by the Natural Environment Research Council, UK, to a collaborating team drawn from four institutions: Royal Holloway University of London (grant reference NE/E015905/1), the Natural History Museum, London (NE/E015913/1), Oxford University (NE/E015670/1) and the University of Southampton, including the National Oceanography Centre (NE/01531X/1). The authors also wish to record their deep gratitude to four members of the scientific community who formed a consultative advisory panel during the lifetime of the RESET project: Professor Barbara Wohlfarth (Stockholm University), Professor Jørgen Peder Steffensen (Niels Bohr Institute, Copenhagen), Dr. Martin Street (Romisch-Germanisches Zentralmuseum, Neuwied) and Professor Clive Oppenheimer (Cambridge University). They provided excellent advice at key stages of the work, which we greatly valued. We also thank Jenny Kynaston (Geography Department, Royal Holloway) for construction of several of the figures in this paper, and Debbie Barrett (Elsevier) and Colin Murray Wallace (Editor-in-Chief, QSR) for their considerable assistance in the production of this special volume.Peer Reviewe
Functional magnetic resonance imaging (fMRI) changes and saliva production associated with acupuncture at LI-2 acupuncture point: a randomized controlled study
<p>Abstract</p> <p>Background</p> <p>Clinical studies suggest that acupuncture can stimulate saliva production and reduce xerostomia (dry mouth). We were interested in exploring the neuronal substrates involved in such responses.</p> <p>Methods</p> <p>In a randomized, sham acupuncture controlled, subject blinded trial, twenty healthy volunteers received true and sham acupuncture in random order. Cortical regions that were activated or deactivated during the interventions were evaluated by functional magnetic resonance imaging (fMRI). Saliva production was also measured.</p> <p>Results</p> <p>Unilateral manual acupuncture stimulation at LI-2, a point commonly used in clinical practice to treat xerostomia, was associated with bilateral activation of the insula and adjacent operculum. Sham acupuncture at an adjacent site induced neither activation nor deactivation. True acupuncture induced more saliva production than sham acupuncture.</p> <p>Conclusion</p> <p>Acupuncture at LI-2 was associated with neuronal activations absent during sham acupuncture stimulation. Neuroimaging signal changes appear correlated to saliva production.</p
Genome-Wide Analysis of Müller Glial Differentiation Reveals a Requirement for Notch Signaling in Postmitotic Cells to Maintain the Glial Fate
Previous studies have shown that Müller glia are closely related to retinal progenitors; these two cell types express many of the same genes and after damage to the retina, Müller glia can serve as a source for new neurons, particularly in non-mammalian vertebrates. We investigated the period of postnatal retinal development when progenitors are differentiating into Müller glia to better understand this transition. FACS purified retinal progenitors and Müller glia from various ages of Hes5-GFP mice were analyzed by Affymetrix cDNA microarrays. We found that genes known to be enriched/expressed by Müller glia steadily increase over the first three postnatal weeks, while genes associated with the mitotic cell cycle are rapidly downregulated from P0 to P7. Interestingly, progenitor genes not directly associated with the mitotic cell cycle, like the proneural genes Ascl1 and Neurog2, decline more slowly over the first 10–14 days of postnatal development, and there is a peak in Notch signaling several days after the presumptive Müller glia have been generated. To confirm that Notch signaling continues in the postmitotic Müller glia, we performed in situ hybridization, immunolocalization for the active form of Notch, and immunofluorescence for BrdU. Using genetic and pharmacological approaches, we found that sustained Notch signaling in the postmitotic Müller glia is necessary for their maturation and the stabilization of the glial identity for almost a week after the cells have exited the mitotic cell cycle
Promoting Scotland, diplomacy and influence through sport
Sport is being used by a number of countries to raise profile, and create influence. Sports diplomacy has an increasing presence in terms of theory, practice and evidence within international relations. Sports diplomacy may occur both within sport and through sport. The channels through which this is facilitated are complex. Scotland has much to learn from places such as Australia that have put in place a dedicated four-year sports diplomacy strategy. The article sets out to answer key questions and doing so suggests that Scottish sport is capable of making the art of the possible, possible, but that Scotland has yet to grasp the opportunities provided by sport’s global currency. The article concludes by making six recommendations
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