117,713 research outputs found
Specialization of neural mechanisms underlying face recognition in human infants
Newborn infants respond preferentially to simple face-like patterns, raising the possibility that the face-specific region, identified in the adult cortex are functioning from birth. We sought to evaluate this hypothesis by characterizing the specificity Of infants' electrocortical responses to faces in two ways: (1) comparing responses to faces of humans with those to faces of nonhuman primates; and 2) comparing responses to upright and inverted faces. Adults' face-responsive N170 event-related potential (ERP) component showed specificity to upright human faces that was not observable at any point in the ERPs Of infants. A putative "infant N170" did show sensitivity to the species of the face, but the orientation of the face did not influence processing until a later stage. These findings suggest a process of gradual specialization of cortical face processing systems during postnatal development
Collective frames of reference, recognition, and managers' mental models of competition: a test in two industries
This work was supported by ESRC grant no. R000232883.Managers draw upon sources of collective knowledge to cognitively represent strategic
issues. It has also be argued that cognition is embedded in social interaction, enabling
managers to recognize of others’ cognitions. In two separate industries, this study found
that the influences upon managers’ mental models of their competitive environment include
industry membership, organizational membership, and management level. The results
indicate further that recognition of others’ mental models may be more pronounced than
cognitive similarity.School of Managemen
Application of the dual-kinetic-balance sets in the relativistic many-body problem of atomic structure
The dual-kinetic-balance (DKB) finite basis set method for solving the Dirac
equation for hydrogen-like ions [V. M. Shabaev et al., Phys. Rev. Lett. 93,
130405 (2004)] is extended to problems with a non-local spherically-symmetric
Dirac-Hartree-Fock potential. We implement the DKB method using B-spline basis
sets and compare its performance with the widely-employed approach of Notre
Dame (ND) group [W.R. Johnson and J. Sapirstein, Phys. Rev. Lett. 57, 1126
(1986)]. We compare the performance of the ND and DKB methods by computing
various properties of Cs atom: energies, hyperfine integrals, the
parity-non-conserving amplitude of the transition, and the
second-order many-body correction to the removal energy of the valence
electrons. We find that for a comparable size of the basis set the accuracy of
both methods is similar for matrix elements accumulated far from the nuclear
region. However, for atomic properties determined by small distances, the DKB
method outperforms the ND approach. In addition, we present a strategy for
optimizing the size of the basis sets by choosing progressively smaller number
of basis functions for increasingly higher partial waves. This strategy
exploits suppression of contributions of high partial waves to typical
many-body correlation corrections.Comment: 10 page
External morphology of eyes and Nebenaugen of caridean decapods–ecological and systematic considerations
Most caridean decapods have compound eyes of the reflecting superposition kind, and additionally some possess an accessory eye-like organ of unknown function, also referred to as the nebenauge.We examined 308 caridean genera to assess the general morphology of the eye, rostrum length, eye diameter and the presence or absence and, when present, the diameter of the nebenauge.We have attempted to relate these data to ecological and taxonomic considerations.We consider there to be 6 distinct eye types based on the margin between the eyestalk and cornea. The presence of nebenaugen appears to be generally linked to an active lifestyle, as evidenced by the fact that species that have nebenaugen tend to have larger eyes and are more likely to have a distinct rostrum.We suggest that the inconsistencies in its presence/absence under both systematic and ecological lenses may indicate that when present it has various roles relating to behavioural and physiological rhythms
Prior upper body exercise reduces cycling work capacity but not critical power
Purpose: This study examined whether metabolite accumulation, induced by prior upper body exercise, affected the power–duration relationship for leg cycle ergometry
A tale of three cities: persisting high HIV prevalence, risk behaviour and undiagnosed infection in community samples of men who have sex with men
Objectives: To examine the geographical variations in HIV prevalence (diagnosed and undiagnosed), use of sexual health services, sexually transmitted infections and sexual behaviour in a community sample of men who have sex with men in three cities in England, specifically London, Brighton and Manchester.Methods: Cross-sectional surveys of men visiting gay community venues in three large cities in England. Men self-completed a questionnaire and provided an anonymous oral fluid sample for HIV antibody testing.Results: HIV prevalence ranged from 8.6% to 13.7% in the three cities. Over one-third of HIV infection remained undiagnosed in all sites despite 69% of HIV-positive men reporting attending a genitourinary medicine clinic in the last year. Similar and high levels of risk behaviour were reported in all three cities. 18% of HIV-negative men and 37% of HIV-positive men reported unprotected anal intercourse with more than one partner in the last year. 20% of negative men and 41% of positive men reported an STI in the last year.Conclusions: Across all cities, despite widespread availability of anti-retroviral treatment and national policy to promote HIV testing, many HIV infections remain undiagnosed. Data from this community sample demonstrate high levels of risk behaviour and STI incidence, especially among those who are HIV positive. Renewed efforts are needed to increase diagnosis and to reduce risk behaviour to stem the continuing transmission of HIV
Improving Transient Performance of Adaptive Control Architectures using Frequency-Limited System Error Dynamics
We develop an adaptive control architecture to achieve stabilization and
command following of uncertain dynamical systems with improved transient
performance. Our framework consists of a new reference system and an adaptive
controller. The proposed reference system captures a desired closed-loop
dynamical system behavior modified by a mismatch term representing the
high-frequency content between the uncertain dynamical system and this
reference system, i.e., the system error. In particular, this mismatch term
allows to limit the frequency content of the system error dynamics, which is
used to drive the adaptive controller. It is shown that this key feature of our
framework yields fast adaptation with- out incurring high-frequency
oscillations in the transient performance. We further show the effects of
design parameters on the system performance, analyze closeness of the uncertain
dynamical system to the unmodified (ideal) reference system, discuss robustness
of the proposed approach with respect to time-varying uncertainties and
disturbances, and make connections to gradient minimization and classical
control theory.Comment: 27 pages, 7 figure
Linking eye design with host symbiont relationships in pontoniine shrimps (crustacea, decapoda, palaemonidae)
Symbiosis is prevalent in the marine environment with many studies examining the effects of such interactions between host and symbiont. Pontoniine shrimps are a group whose ecology is characterised by symbiotic interactions. This investigation examines the gross morphology of Pontoniinae compound eyes and superficial optical parameters with reference to their symbiotic relationship or lifestyle category; free-living, ectosymbiont, endosymbiont (bivalves) or endosymbiont (non-bivalves). The eye morphologies of free-living and ectosymbiotic species are very similar, yet differ from both forms of endosymbiotic species. Endosymbionts have significantly smaller and simpler eyes with larger facets and bigger interommatidial angles and eye parameters for increased sensitivity levels. However bivalve endosymbionts form an intermediary group between non-bivalve endosymbionts and ectosymbionts as a result of their more active lifestyle. The accessory eye or "nebenauge", although of uncertain function, commonly occurs in free-living Pontoniinae species but rarely in endosymbionts apart from in more primitive species. The variation in morphology reflects tensions between functional requirements and ecological pressures that have strongly influenced eye design in Pontoniinae. © 2014 Dobson et al
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