931 resultados para Fighting asymmetry
Resumo:
. Haigh, David; Birrell, Helen C.; Cantello, Barrie C. C.; Hindley, Richard M.; Ramaswamy, Anantha; Rami, Harshad K.; Stevens, Nicola C. Department of Medicinal Chemistry, SmithKline Beecham Pharmaceuticals, Essex, UK. Tetrahedron: Asymmetry (1999), 10(7), 1335-1351. Publisher: Elsevier Science Ltd., CODEN: TASYE3 ISSN: 0957-4166. Journal written in English. CAN 131:144536 AN 1999:369513 CAPLUS (Copyright (C) 2009 ACS on SciFinder (R)) Abstract The synthesis of a new series of potent 2-oxy-3-arylpropanoic acid antihyperglycemic agents in both racemic and non-racemic form is described. (the biol. activity of these compds. was not reported here). Resoln. of racemic acids is accomplished via amide formation with either (S)-2-phenylglycinol or (S)-4-benzyl-2-oxazolidinone as complementary resolving agents. The target compds. were ?-alkoxy-4-[2-[(2-benzoxazolyl)amino]ethoxy]benzenepropanoic acid derivs.
Resumo:
The light emission spectrum from a scanning tunnelling microscope (LESTM) is investigated as a function of relative humidity and shown to provide a novel and sensitive means for probing the growth and properties of a water meniscus on the nanometre scale. An empirical model of the light emission process is formulated and applied successfully to replicate the decay in light intensity and spectral changes observed with increasing relative humidity. The modelling indicates a progressive water filling of the tip-sample junction with increasing humidity or, more pertinently, of the volume of the localized surface plasmons responsible for light emission; it also accounts for the effect of asymmetry in structuring of the water molecules with respect to the polarity of the applied bias. This is juxtaposed with the case of a non-polar liquid in the tip-sample nanocavity where no polarity dependence of the light emission is observed. In contrast to the discrete detection of the presence/absence of a water bridge in other scanning probe experiments through measurement of the feedback parameter for instrument control, LESTM offers a means of continuously monitoring the development of the water bridge with sub-nanometre sensitivity. The results are relevant to applications such as dip-pen nanolithography and electrochemical scanning probe microscopy.
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This paper concerns a recently discovered, puzzling asymmetry in judgments of whether an action is intentional or not (Knobe 2003a, b). We report new data replicating the asymmetry in the context of scenarios wherein an agent achieves an amoral or immoral goal due to luck. Participants’ justifications of their judgments of the intentionality of the agent’s action indicate that two distinct folk concepts of intentional action played a role in their judgments. When viewed from this perspective, the puzzle disappears, although the asymmetry remains
Resumo:
An idealized jellium model of conducting nanowires with a geometric constriction is investigated by density functional theory (DFT) in the local spin density (LSD) approximation. The results reveal a fascinating variety of spin and charge patterns arising in wires of sufficiently low (r(s) >= 15) average electron density, pinned at the indentation by an apparent attractive interaction with the constriction. The spin-resolved frequency-dependent conductivity shows a marked asymmetry in the two spin channels, reflecting the spontaneous spin polarization around the wire neck. The relevance of the computational results is discussed in relation to the so-called 0.7 anomaly found by experiments in the low-frequency conductivity of nanowires at near-breaking conditions (see 2008 J. Phys.: Condens Matter 20, special issue on the 0.7 anomaly). Although our mean-field approach cannot account for the intrinsic many-body effects underlying the 0.7 anomaly, it still provides a diagnostic tool to predict impending transitions in the electronic structure.
Resumo:
The surface properties of the jellium model have been investigated by large supercell computations in the density functional theory-local spin-density (DFT-LSD) approach for planar slabs with up to 1000 electrons. A wide interval of densities has been explored, extending into the stability range of the Wigner crystal. Most computations have been carried out on nominally paramagnetic samples with an equal number of spin-up and spin-down electrons. The results show that within DFT-LSD spontaneous spin polarization and charge localization start nearly simultaneously at the surface for r(s) similar to 20, then, with decreasing density, they progress toward the center of the slab. Electrons are fully localized and spin polarized at r(s) = 30. At this density the charge distribution is the superposition of disjoint charge blobs, each corresponding to one electron. The distribution of blobs displays both regularities and disorder, the first being represented by well-defined planes and simple in-plane geometries, and the latter by a variety of surface defects. The surface energy, surface dipole, electric polarisability, and magnetization pattern have been determined as a function of density. All these quantities display characteristic anomalies at the density of the localization transition. The analysis of the low-frequency electric conductivity shows that in the fluid paramagnetic regime the in-plane current preferentially flows in the central region of the slab and the two spin channels are equally conducting. In the charge localized, spin-polarized regime, conductivity is primarily a surface effect, and an apparent asymmetry is observed in the two spin currents.
Resumo:
Context. Hot-Jupiter planets must form at large separations from their host stars where the temperatures are cool enough for their cores to condense. They then migrate inwards to their current observed orbital separations. Different theories of how this migration occurs lead to varying distributions of orbital eccentricity and the alignment between the rotation axis of the star and the orbital axis of the planet. Aims: The spin-orbit alignment of a transiting system is revealed via the Rossiter-McLaughlin effect, which is the anomaly present in the radial velocity measurements of the rotating star during transit due to the planet blocking some of the starlight. In this paper we aim to measure the spin-orbit alignment of the WASP-3 system via a new way of analysing the Rossiter-McLaughlin observations. Methods: We apply a new tomographic method for analysing the time variable asymmetry of stellar line profiles caused by the Rossiter-McLaughlin effect. This new method eliminates the systematic error inherent in previous methods used to analyse the effect. Results: We find a value for the projected stellar spin rate of v sin i = 13.9 ± 0.03 km s-1 which is in agreement with previous measurements but has a much higher precision. The system is found to be well aligned, with ? = 5-5+6° which favours an evolutionary history for WASP-3b involving migration through tidal interactions with a protoplanetary disc. From comparison with isochrones we put an upper limit on the age of the star of 2 Gyr.
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Spinor Bose condensates loaded in optical lattices have a rich phase diagram characterized by different magnetic order. Here we apply the density matrix renormalization group to accurately determine the phase diagram for spin-1 bosons loaded on a one-dimensional lattice. The Mott lobes present an even or odd asymmetry associated to the boson filling. We show that for odd fillings the insulating phase is always in a dimerized state. The results obtained in this work are also relevant for the determination of the ground state phase diagram of the S=1 Heisenberg model with biquadratic interaction.
Resumo:
For the first time, the development of paw preferences in the domestic cat, Felis silvestris catus, is explored. Twelve cats were tested at ages 12 weeks, 6 months, and 1 year on a challenge requiring them to use one of their paws to retrieve food. To control for repeated testing of the same cats at different ages, the subjects' paw preferences were compared with those of cats tested just once, at 6 months (n = 11) or 1 year (n = 14) of age. Analysis revealed a significant effect of age on the distribution of cats' paw preferences. Cats were significantly more likely to be ambilateral than paw preferent at 12 weeks and at 6 months but more likely to display a lateral bias in paw use at 1 year. There was a significant positive correlation between cats' paw preferences at 6 months and at 1 year. Lateralized behavior was strongly sex related. Females had a greater preference for using their right paw; males were significantly more inclined to adopt their left. Analysis revealed no significant difference in the direction or strength of paw preferences of cats tested longitudinally or cross-sectionally at 6 months or 1 year of age. Findings indicate that cats develop paw preferences by 1 year and hint at a relative stability in preferred paw use over time. The strong sex effect observed strengthens the case for the influence of a biological mechanism in the emergence of motor asymmetry in cats.
Resumo:
Objective
To examine whether students’ school engagement, relationships with teachers, educational aspirations and involvement in fights at school are associated with various measures of subsequent substance use.
Methods
Data were drawn from the Belfast Youth Development Study (n = 2968). Multivariate logistic models examined associations between school-related factors (age 13/14) and substance use (age 15/16).
Results
The two factors which were consistently and independently associated with regular substance use among both males and females were student–teacher relationships and fighting at school: positive teacher-relationships reduced the risk of daily smoking by 48%, weekly drunkenness by 25%, and weekly cannabis use by 52%; being in a fight increased the risk of daily smoking by 54%, weekly drunkenness by 31%, and weekly cannabis use by 43%. School disengagement increased the likelihood of smoking and cannabis use among females only.
Conclusion
Further research should focus on public health interventions promoting positive relationships and safety at school.
Resumo:
This article investigates a significant problem in contemporary critical theory, namely its failure to address effectively the possibility that a campaign of political violence may be a legitimate means of fighting grave injustice. Having offered a working definition of ‘political violence’, I argue that critical theory should be focused on experiences of injustice rather than on ideals of justice. I then explore the reasons as to why, save for some intriguing remarks on retrospective legitimation, Jürgen Habermas has not addressed this issue directly. While Axel Honneth's recognition theory may have greater potential here, the absence of explicit consideration of the matter by him leaves considerable work to do. I introduce five questions in the concluding section that provide a starting point in setting out an appropriately stringent, normative test for claims that support violent action against injustice.
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The state disturbance induced by locally measuring a quantum system yields a signature of nonclassical correlations beyond entanglement. Here, we present a detailed study of such correlations for two-qubit mixed states. To overcome the asymmetry of quantum discord and the unfaithfulness of measurement-induced disturbance (severely overestimating quantum correlations), we propose an ameliorated measurement-induced disturbance as nonclassicality indicator, optimized over joint local measurements, and we derive its closed expression for relevant two-qubit states. We study its analytical relation with discord, and characterize the maximally quantum-correlated mixed states, that simultaneously extremize both quantifiers at given von Neumann entropy: among all two-qubit states, these states possess the most robust quantum correlations against noise.
Resumo:
We examine lateralization of lateral displays in convict cichlids, Amatitlania nigrofasciata, and show a population level preference for showing the right side. This enables contesting pairs of fish to align in a head-to-tail posture, facilitating other activities. We found individuals spent a shorter mean time in each left compared with each right lateral display. This lateralization could lead to contesting pairs using a convention to align in a predictable head-to-tail arrangement to facilitate the assessment of fighting ability. It has major implications for the common use of mirror images to study fish aggression, because the 'opponent' would never cooperate and would consistently show the incorrect side when the real fish shows the correct side. With the mirror, the 'normal' head-to-tail orientation cannot be achieved.
Resumo:
Background: There is growing interest in the potential utility of molecular diagnostics in improving the detection of life-threatening infection (sepsis). LightCycler® SeptiFast is a multipathogen probebased real-time PCR system targeting DNA sequences of bacteria and fungi present in blood samples within a few hours. We report here the protocol of the first systematic review of published clinical diagnostic accuracy studies of this technology when compared with blood culture in the setting of suspected sepsis. Methods/design: Data sources: the Cochrane Database of Systematic Reviews, the Database of Abstracts of Reviews of Effects (DARE), the Health Technology Assessment Database (HTA), the NHS Economic Evaluation Database (NHSEED), The Cochrane Library, MEDLINE, EMBASE, ISI Web of Science, BIOSIS Previews, MEDION and the Aggressive Research Intelligence Facility Database (ARIF). Study selection: diagnostic accuracy studies that compare the real-time PCR technology with standard culture results performed on a patient's blood sample during the management of sepsis. Data extraction: three reviewers, working independently, will determine the level of evidence, methodological quality and a standard data set relating to demographics and diagnostic accuracy metrics for each study. Statistical analysis/data synthesis: heterogeneity of studies will be investigated using a coupled forest plot of sensitivity and specificity and a scatter plot in Receiver Operator Characteristic (ROC) space. Bivariate model method will be used to estimate summary sensitivity and specificity. The authors will investigate reporting biases using funnel plots based on effective sample size and regression tests of asymmetry. Subgroup analyses are planned for adults, children and infection setting (hospital vs community) if sufficient data are uncovered. Dissemination: Recommendations will be made to the Department of Health (as part of an open-access HTA report) as to whether the real-time PCR technology has sufficient clinical diagnostic accuracy potential to move forward to efficacy testing during the provision of routine clinical care.
Resumo:
The POINT-AGAPE collaboration is currently searching for massive compact halo objects (MACHOs) toward the Andromeda galaxy (M31). The survey aims to exploit the high inclination of the M31 disk, which causes an asymmetry in the spatial distribution of M31 MACHOs. Here, we investigate the effects of halo velocity anisotropy and flattening on the asymmetry signal using simple halo models. For a spherically symmetric and isotropic halo, we find that the underlying pixel lensing rate in far-disk M31 MACHOs is more than 5 times the rate of near-disk events. We find that the asymmetry is further increased by about 30% if the MACHOs occupy radial orbits rather than tangential orbits, but it is substantially reduced if the MACHOs lie in a flattened halo. However, even for halos with a minor- to major-axis ratio of q = 0.3, the number of M31 MACHOs in the far side outnumber those in the near side by a factor of similar to2. There is also a distance asymmetry, in that the events on the far side are typically farther from the major axis. We show that, if this positional information is exploited in addition to number counts, then the number of candidate events required to confirm asymmetry for a range of flattened and anisotropic halo models is achievable, even with significant contamination by variable stars and foreground microlensing events. For pixel lensing surveys that probe a representative portion of the M31 disk, a sample of around 50 candidates is likely to be sufficient to detect asymmetry within spherical halos, even if half the sample is contaminated, or to detect asymmetry in halos as flat as q = 0.3, provided less than a third of the sample comprises contaminants. We also argue that, provided its mass-to-light ratio is less than 100, the recently observed stellar stream around M31 is not problematic for the detection of asymmetry.
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We report spatially and temporally resolved measurements of self-generated multi-megagauss magnetic fields produced during ultrahigh intensity laser plasma interactions. Spatially resolved measurements of the magnetic fields show an asymmetry in the distribution of field with respect to the angle of laser incidence. Temporally resolved measurements of the self-generated third harmonic suggest that the strength of the magnetic field is proportional to the square root of laser intensity (i.e., the laser B-field) during the rise of the laser pulse. The experimental results are compared with numerical simulations using a particle-in-cell code which also shows clear asymmetry of the field profile and similar magnetic field growth rates and scalings.