Global Facilitation of Attended Features Is Obligatory and Restricts Divided Attention

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Out of equilibrium quantum field dynamics of an initial thermal state after a change in the external field

The effects of the initial temperature in the out of equilibrium quantum field dynamics in the presence of an homogeneous external field are investigated. We consider an initial thermal state of temperature T for a constant external field J. A subsequent sign flip of the external field, J to -J, gives rise to an out of equilibrium nonperturbative quantum field dynamics. The dynamics is studied here for the symmetry broken lambda(Phi^2)^2 scalar N component field theory in the large N limit. We find a dynamical effective potential for the expectation value that helps to understand the dynamics. The dynamics presents two regimes defined by the presence or absence of a temporal trapping close to the metastable equilibrium position of the potential. The two regimes are separated by a critical value of the external field that depends on the initial temperature. The temporal trapping is shorter for larger initial temperatures or larger external fields. Parametric resonances and spinodal instabilities amplify the quantum fluctuations in the field components transverse to the external field. When there is a temporal trapping this is the main mechanism that allows the system to escape from the metastable state for large N. Subsequently backreaction stops the growth of the quantum fluctuations and the system enters a quasiperiodic regime.Comment: LaTeX, 19 pages, 12 .eps figures, improved version to appear in Phys Rev

Generalized Parton Distributions from Hadronic Observables: Zero Skewness

We propose a physically motivated parametrization for the unpolarized generalized parton distributions. At zero value of the skewness variable, $\zeta$, the parametrization is constrained by simultaneously fitting the experimental data on both the nucleon elastic form factors and the deep inelastic structure functions. A rich phenomenology can be addressed based on this parametrization. In particular, we track the behavior of the average: {\it i)} interparton distances as a function of the momentum fraction, $X$, {\it ii)} $X$ as a function of the four-momentum transfer, $t$; and {\it iii)} the intrinsic transverse momentum $k_\perp$ as a function of $X$. We discuss the extension of our parametrization to $\zeta \neq 0$ where additional constraints are provided by higher moments of the generalized parton distributions obtained from {\it ab initio} lattice QCD calculations.Comment: 42 pages, 21 figure

Plasmodium falciparum glutamate dehydrogenase a is dispensable and not a drug target during erythrocytic development

<p>Background: Plasmodium falciparum contains three genes encoding potential glutamate dehydrogenases. The protein encoded by gdha has previously been biochemically and structurally characterized. It was suggested that it is important for the supply of reducing equivalents during intra-erythrocytic development of Plasmodium and, therefore, a suitable drug target.</p> <p>Methods: The gene encoding the NADP(H)-dependent GDHa has been disrupted by reverse genetics in P. falciparum and the effect on the antioxidant and metabolic capacities of the resulting mutant parasites was investigated.</p> <p>Results: No growth defect under low and elevated oxygen tension, no up-or down-regulation of a number of antioxidant and NADP(H)-generating proteins or mRNAs and no increased levels of GSH were detected in the D10(Delta gdha) parasite lines. Further, the fate of the carbon skeleton of [(13)C] labelled glutamine was assessed by metabolomic studies, revealing no differences in the labelling of a-ketoglutarate and other TCA pathway intermediates between wild type and mutant parasites.</p> <p>Conclusions: First, the data support the conclusion that D10(Delta gdha) parasites are not experiencing enhanced oxidative stress and that GDHa function may not be the provision of NADP(H) for reductive reactions. Second, the results imply that the cytosolic, NADP(H)-dependent GDHa protein is not involved in the oxidative deamination of glutamate but that the protein may play a role in ammonia assimilation as has been described for other NADP(H)dependent GDH from plants and fungi. The lack of an obvious phenotype in the absence of GDHa may point to a regulatory role of the protein providing glutamate (as nitrogen storage molecule) in situations where the parasites experience a limiting supply of carbon sources and, therefore, under in vitro conditions the enzyme is unlikely to be of significant importance. The data imply that the protein is not a suitable target for future drug development against intra-erythrocytic parasite development.</p&gt

‘It's like the bad guy in a movie who just doesn't die’ : a qualitative exploration of young people's adaptation to eczema and implications for self‐care

Background Eczema is a common childhood inflammatory skin condition, affecting more than one in five children. A popular perception is that children ‘outgrow eczema’, although epidemiological studies have shown that, for many, eczema follows a lifelong episodic course. Objectives To explore the perceptions of young people about the nature of their eczema and how these perceptions relate to their self‐care and adapting to living with eczema. Methods This is a secondary inductive thematic analysis of interviews conducted for Healthtalk.org. In total 23 interviews with young people with eczema were included. Of the 23 participants, 17 were female and six male, ranging from 17 to 25 years old. Results Participants generally experienced eczema as an episodic long‐term condition and reported a mismatch between information received about eczema and their experiences. The experience of eczema as long term and episodic had implications for self‐care, challenging the process of identifying triggers of eczema flare‐ups and evaluating the success of treatment regimens. Participants’ experiences of eczema over time also had implications for adaptation and finding a balance between accepting eczema as long term and hoping it would go away. This linked to a gradual shift in treatment expectations from ‘cure’ to ‘control’ of eczema. Conclusions For young people who continue to experience eczema beyond childhood, a greater focus on self‐care for a long‐term condition may be helpful. Greater awareness of the impact of early messages around ‘growing out of’ eczema and provision of high‐quality information may help patients to manage expectations and support adaptation to treatment regimens

Dust-forming molecules in VY Canis Majoris (and Betelgeuse)

The formation of inorganic dust in circumstellar environments of evolved stars is poorly understood. Spectra of molecules thought to be most important for the nucleation, i.e. AlO, TiO, and TiO2, have been recently detected in the red supergiant VY CMa. These molecules are effectively formed in VY CMa and the observations suggest that non-equilibrium chemistry must be involved in their formation and nucleation into dust. In addition to exploring the recent observations of VY CMa, we briefly discuss the possibility of detecting these molecules in the dust-poor circumstellar environment of Betelgeuse.Comment: contribution to Betelgeuse Workshop 2012: "The physics of Red Supergiants: recent advances and open questions", 26-29 Nov 2012 Paris (France

Gravitational Waves from Axisymmetric, Rotational Stellar Core Collapse

We have carried out an extensive set of two-dimensional, axisymmetric, purely-hydrodynamic calculations of rotational stellar core collapse with a realistic, finite-temperature nuclear equation of state and realistic massive star progenitor models. For each of the total number of 72 different simulations we performed, the gravitational wave signature was extracted via the quadrupole formula in the slow-motion, weak-field approximation. We investigate the consequences of variation in the initial ratio of rotational kinetic energy to gravitational potential energy and in the initial degree of differential rotation. Furthermore, we include in our model suite progenitors from recent evolutionary calculations that take into account the effects of rotation and magnetic torques. For each model, we calculate gravitational radiation wave forms, characteristic wave strain spectra, energy spectra, final rotational profiles, and total radiated energy. In addition, we compare our model signals with the anticipated sensitivities of the 1st- and 2nd-generation LIGO detectors coming on line. We find that most of our models are detectable by LIGO from anywhere in the Milky Way.Comment: 13 pages, 22 figures, accepted for publication in ApJ (v600, Jan. 2004). Revised version: Corrected typos and minor mistakes in text and references. Minor additions to the text according to the referee's suggestions, conclusions unchange