591 research outputs found
Turning Points in the Evolution of Isolated Neutron Stars' Magnetic Fields
During the life of isolated neutron stars (NSs) their magnetic field passes
through a variety of evolutionary phases. Depending on its strength and
structure and on the physical state of the NS (e.g. cooling, rotation), the
field looks qualitatively and quantitatively different after each of these
phases. Three of them, the phase of MHD instabilities immediately after NS's
birth, the phase of fallback which may take place hours to months after NS's
birth, and the phase when strong temperature gradients may drive thermoelectric
instabilities, are concentrated in a period lasting from the end of the
proto--NS phase until 100, perhaps 1000 years, when the NS has become almost
isothermal. The further evolution of the magnetic field proceeds in general
inconspicuous since the star is in isolation. However, as soon as the product
of Larmor frequency and electron relaxation time, the so-called magnetization
parameter, locally and/or temporally considerably exceeds unity, phases, also
unstable ones, of dramatic changes of the field structure and magnitude can
appear. An overview is given about that field evolution phases, the outcome of
which makes a qualitative decision regarding the further evolution of the
magnetic field and its host NS.Comment: References updated, typos correcte
Challenging Perceptions of Disability through Performance Poetry Methods: The "Seen but Seldom Heard" Project.
This paper considers performance poetry as a method to explore lived experiences
of disability. We discuss how poetic inquiry used within a participatory arts-based
research framework can enable young people to collectively question societyâs
attitudes and actions towards disability. Poetry will be considered as a means to
develop a more accessible and effective arena in which young people with direct
experience of disability can be empowered to develop new skills that enable them
to tell their own stories. Discussion of how this can challenge audiences to critically reflect upon their own perceptions of disability will also be developed
Monitoring and Pay: An Experiment on Employee Performance under Endogenous Supervision
We present an experimental test of a shirking model where monitoring intensity is endogenous and effort a continuous variable. Wage level, monitoring intensity and consequently the desired enforceable effort level are jointly determined by the maximization problem of the firm. As a result, monitoring and pay should be complements. In our experiment, between and within treatment variation is qualitatively in line with the normative predictions of
the model under standard assumptions. Yet, we also find evidence for reciprocal behavior. Our data analysis shows, however, that it does not pay for the employer to solely rely on the reciprocity of employees
Endomicroscopic and transcriptomic analysis of impaired barrier function and malabsorption in environmental enteropathy
Introduction: Environmental enteropathy (EE) is associated with growth failure, micronutrient malabsorption and impaired responses to oral vaccines. We set out to define cellular mechanisms of impaired barrier function in EE and explore protective mechanisms. Methods: We studied 49 adults with environmental enteropathy in Lusaka, Zambia using confocal laser endomicroscopy (CLE); histology, immunohistochemistry and mRNA sequencing of small intestinal biopsies; and correlated these with plasma lipopolysaccharide (LPS) and a zinc uptake test. Results: CLE images (median 134 for each study) showed virtually ubiquitous small intestinal damage. Epithelial defects, imaged by histology and claudin 4 immunostaining, were predominantly seen at the tips of villi and corresponded with leakage imaged in vivo by CLE. In multivariate analysis, circulating log-transformed LPS was correlated with cell shedding events (ÎČ = 0.83; P = 0.035) and with serum glucagon-like peptide-2 (ÎČ = -0.13; P = 0.007). Zinc uptake from a test dose of 25mg was attenuated in 30/47 (64%) individuals and in multivariate analysis was reduced by HIV, but positively correlated with GLP-2 (ÎČ = 2.72; P = 0.03). There was a U-shaped relationship between circulating LPS and villus surface area. Transcriptomic analysis identified 23 differentially expressed genes in severe enteropathy, including protective peptides and proteins. Conclusions: Confocal endomicroscopy, claudin 4 immunostaining and histology identify epithelial defects which are probably sites of bacterial translocation, in the presence of which increased epithelial surface area increases the burden of translocation. GLP 2 and other protective peptides may play an important role in mucosal protection in EE
Efficacy of individualised starting dose (isd) and fixed starting dose (fsd) of niraparib per investigator assessment (ia) in newly diagnosed advanced ovarian cancer (oc) patients
Niraparib is a poly(ADP-ribose) polymerase inhibitor approved for maintenance treatment of patients with
newly diagnosed or recurrent OC that responded to platinumbased chemotherapy and treatment in heavily-pretreated recurrent OC. Here we report efficacy in patients receiving the
FSD and ISD in the PRIMA/ENGOT-OV26/GOG-3012 trial
(NCT02655016)
Loss of RhoB Expression Enhances the Myelodysplastic Phenotype of Mammalian Diaphanous-Related Formin mDia1 Knockout Mice
Myelodysplastic syndrome (MDS) is characterized by ineffective hematopoiesis and hyperplastic bone marrow. Complete loss or interstitial deletions of the long arm of chromosome 5 occur frequently in MDS. One candidate tumor suppressor on 5q is the mammalian Diaphanous (mDia)-related formin mDia1, encoded by DIAPH1 (5q31.3). mDia-family formins act as effectors for Rho-family small GTP-binding proteins including RhoB, which has also been shown to possess tumor suppressor activity. Mice lacking the Drf1 gene that encodes mDia1 develop age-dependent myelodysplastic features. We crossed mDia1 and RhoB knockout mice to test whether the additional loss of RhoB expression would compound the myelodysplastic phenotype. Drf1â/âRhoBâ/â mice are fertile and develop normally. Relative to age-matched Drf1â/âRhoB+/â mice, the age of myelodysplasia onset was earlier in Drf1â/âRhoBâ/â animalsâincluding abnormally shaped erythrocytes, splenomegaly, and extramedullary hematopoiesis. In addition, we observed a statistically significant increase in the number of activated monocytes/macrophages in both the spleen and bone marrow of Drf1â/âRhoBâ/â mice relative to Drf1â/âRhoB+/â mice. These data suggest a role for RhoB-regulated mDia1 in the regulation of hematopoietic progenitor cells
Combining ââreal effortââ with induced effort costs: the ball-catching task
We introduce the âball-catching taskâ, a novel computerized task, which combines a tangible action (âcatching ballsâ) with induced material cost of effort. The central feature of the ball-catching task is that it allows researchers to manipulate the cost of effort function as well as the production function, which permits quantitative predictions on effort provision. In an experiment with piece-rate incentives we find that the comparative static and the point predictions on effort provision are remarkably accurate. We also present experimental findings from three classic experiments, namely, team production, gift exchange and tournament, using the task. All of the results are closely in line with the stylized facts from experiments using purely induced values. We conclude that the ball-catching task combines the advantages of real effort tasks with the use of induced values, which is useful for theory-testing purposes as well as for applications
Myc depletion induces a pluripotent dormant state mimicking diapause
Mouse embryonic stem cells (ESCs) are maintained in a naive ground state of pluripotency in the presence of MEK and GSK3 inhibitors. Here, we show that ground-state ESCs express low Myc levels. Deletion of both c-myc and N-myc (dKO) or pharmacological inhibition of Myc activity strongly decreases transcription, splicing, and protein synthesis, leading to proliferation arrest. This process is reversible and occurs without affecting pluripotency, suggesting that Myc-depleted stem cells enter a state of dormancy similar to embryonic diapause. Indeed, c-Myc is depleted in diapaused blastocysts, and the differential expression signatures of dKO ESCs and diapaused epiblasts are remarkably similar. Following Myc inhibition, pre-implantation blastocysts enter biosynthetic dormancy but can progress through their normal developmental program after transfer into pseudo-pregnant recipients. Our study shows that Myc controls the biosynthetic machinery of stem cells without affecting their potency, thus regulating their entry and exit from the dormant state.This work was supported by the FOR2033 and SFB873 funded by the Deutsche Forschungsgemeinschaft (DFG), the Dietmar Hopp Foundation (all to A.T.), and the Wellcome Trust (to A.S.)
Macro-Climatic Distribution Limits Show Both Niche Expansion and Niche Specialization among C4 Panicoids
Grasses are ancestrally tropical understory species whose current dominance in warm open habitats is linked to the evolution of C4 photosynthesis. C4 grasses maintain high rates of photosynthesis in warm and water stressed environments, and the syndrome is considered to induce niche shifts into these habitats while adaptation to cold ones may be compromised. Global biogeographic analyses of C4 grasses have, however, concentrated on diversity patterns, while paying little attention to distributional limits. Using phylogenetic contrast analyses, we compared macro-climatic distribution limits among ~1300 grasses from the subfamily Panicoideae, which includes 4/5 of the known photosynthetic transitions in grasses. We explored whether evolution of C4 photosynthesis correlates with niche expansions, niche changes, or stasis at subfamily level and within the two tribes Paniceae and Paspaleae. We compared the climatic extremes of growing season temperatures, aridity, and mean temperatures of the coldest months. We found support for all the known biogeographic distribution patterns of C4 species, these patterns were, however, formed both by niche expansion and niche changes. The only ubiquitous response to a change in the photosynthetic pathway within Panicoideae was a niche expansion of the C4 species into regions with higher growing season temperatures, but without a withdrawal from the inherited climate niche. Other patterns varied among the tribes, as macro-climatic niche evolution in the American tribe Paspaleae differed from the pattern supported in the globally distributed tribe Paniceae and at family level.Fil: Aagesen, Lone. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de BotĂĄnica Darwinion. Academia Nacional de Ciencias Exactas, FĂsicas y Naturales. Instituto de BotĂĄnica Darwinion; ArgentinaFil: Biganzoli, Fernando. Universidad de Buenos Aires. Facultad de AgronomĂa. Departamento de MĂ©todos Cuantitativos y Sistemas de InformaciĂłn; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Bena, MarĂa Julia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de BotĂĄnica Darwinion. Academia Nacional de Ciencias Exactas, FĂsicas y Naturales. Instituto de BotĂĄnica Darwinion; ArgentinaFil: Godoy BĂŒrki, Ana Carolina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de BotĂĄnica Darwinion. Academia Nacional de Ciencias Exactas, FĂsicas y Naturales. Instituto de BotĂĄnica Darwinion; ArgentinaFil: Reinheimer, Renata. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Santa Fe. Instituto de AgrobiotecnologĂa del Litoral. Universidad Nacional del Litoral. Instituto de AgrobiotecnologĂa del Litoral; ArgentinaFil: Zuloaga, Fernando Omar. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de BotĂĄnica Darwinion. Academia Nacional de Ciencias Exactas, FĂsicas y Naturales. Instituto de BotĂĄnica Darwinion; Argentin
Flow analysis from multiparticle azimuthal correlations
We present a new method for analyzing directed and elliptic flow in heavy ion
collisions. Unlike standard methods, it separates the contribution of flow to
azimuthal correlations from contributions due to other effects. The separation
relies on a cumulant expansion of multiparticle azimuthal correlations, and
includes corrections for detector inefficiencies. This new method allows the
measurement of the flow of identified particles in narrow phase-space regions,
and can be used in every regime, from intermediate to ultrarelativistic
energies.Comment: 31 pages, revtex. Published version (references added
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