352 research outputs found

    Geologic Setting and Activity of Faults in the San Fernando Area, California

    Get PDF
    The faulting associated with the San Fernando earthquake of February 9, 1971, occurred in the Transverse Ranges structural province, a region noted for its strong and relatively young tectonic deformation. This is, however, the first example of historic surface faulting within the interior of that province

    Geologic Setting and Activity of Faults in the San Fernando Area, California

    Get PDF
    The faulting associated with the San Fernando earthquake of February 9, 1971, occurred in the Transverse Ranges structural province, a region noted for its strong and relatively young tectonic deformation. This is, however, the first example of historic surface faulting within the interior of that province

    Heat exchange mediated by a quantum system

    Full text link
    We consider heat transfer between two thermal reservoirs mediated by a quantum system using the generalized quantum Langevin equation. The thermal reservoirs are treated as ensembles of oscillators within the framework of the Drude-Ullersma model. General expressions for the heat current and thermal conductance are obtained for arbitrary coupling strength between the reservoirs and the mediator and for different temperature regimes. As an application of these results we discuss the origin of Fourier's law in a chain of large, but finite subsystems coupled to each other by the quantum mediators. We also address a question of anomalously large heat current between the STM tip and substrate found in a recent experiment. The question of minimum thermal conductivity is revisited in the framework of scaling theory as a potential application of the developed approach.Comment: 16 pages, 6 figure

    Research Chimpanzees May Get a Break

    Get PDF
    A recent report by the Institute of Medicine leaves few urgent reasons standing for the continued use of chimpanzees in biomedical research. It is high time to think about their retirement, Frans de Waal argues, without neglecting prospects for non-invasive research on behavior, cognition, and genetics

    Ubiquitous Crossmodal Stochastic Resonance in Humans: Auditory Noise Facilitates Tactile, Visual and Proprioceptive Sensations

    Get PDF
    BACKGROUND: Stochastic resonance is a nonlinear phenomenon whereby the addition of noise can improve the detection of weak stimuli. An optimal amount of added noise results in the maximum enhancement, whereas further increases in noise intensity only degrade detection or information content. The phenomenon does not occur in linear systems, where the addition of noise to either the system or the stimulus only degrades the signal quality. Stochastic Resonance (SR) has been extensively studied in different physical systems. It has been extended to human sensory systems where it can be classified as unimodal, central, behavioral and recently crossmodal. However what has not been explored is the extension of this crossmodal SR in humans. For instance, if under the same auditory noise conditions the crossmodal SR persists among different sensory systems. METHODOLOGY/PRINCIPAL FINDINGS: Using physiological and psychophysical techniques we demonstrate that the same auditory noise can enhance the sensitivity of tactile, visual and propioceptive system responses to weak signals. Specifically, we show that the effective auditory noise significantly increased tactile sensations of the finger, decreased luminance and contrast visual thresholds and significantly changed EMG recordings of the leg muscles during posture maintenance. CONCLUSIONS/SIGNIFICANCE: We conclude that crossmodal SR is a ubiquitous phenomenon in humans that can be interpreted within an energy and frequency model of multisensory neurons spontaneous activity. Initially the energy and frequency content of the multisensory neurons' activity (supplied by the weak signals) is not enough to be detected but when the auditory noise enters the brain, it generates a general activation among multisensory neurons of different regions, modifying their original activity. The result is an integrated activation that promotes sensitivity transitions and the signals are then perceived. A physiologically plausible model for crossmodal stochastic resonance is presented

    Conceptualizing national family policies: A capabilities approach

    Get PDF
    Comparative family policy research has advanced significantly in recent years. The growing availability of more and better data have improved our understanding of cross-national similarities and differences in family policies, as well as how they shape the lives of different families. Despite these advancements, comparative family policy research continues to face difficulties. The multifaceted nature of family policies makes cross-country comparisons complex. Conceptualizing our theoretical understanding of which policy aspects matter and why as well as operationalizing them into measurable indicators, often remains problematic for comparative analyses. Using examples of British and Swedish policies on childcare, a policy area particularly prone to conceptual challenges, we discuss the difficulties involved in conceptualizing family policies in comparative research. We argue that taking a capabilities approach provides a useful way forward in the field and show how such a conceptual framework allows us to more meaningfully analyze both work-family policies and their outcomes

    Mn 2+ reduces Y z + in manganese-depleted Photosystem II preparations

    Full text link
    Manganese in the oxygen-evolving complex is a physiological electron donor to Photosystem II. PS II depleted of manganese may oxidize exogenous reductants including benzidine and Mn 2+ . Using flash photolysis with electron spin resonance detection, we examined the room-temperature reaction kinetics of these reductants with Y z + , the tyrosine radical formed in PS II membranes under illumination. Kinetics were measured with membranes that did or did not contain the 33 kDa extrinsic polypeptide of PS II, whose presence had no effect on the reaction kinetics with either reductant. The rate of Y z + reduction by benzidine was a linear function of benzidine concentration. The rate of Y z + reduction by Mn 2+ at pH 6 increased linearly at low Mn 2+ concentrations and reached a maximum at the Mn 2+ concentrations equal to several times the reaction center concentration. The rate was inhibited by K + , Ca 2+ and Mg 2+ . These data are described by a model in which negative charge on the membrane causes a local increase in the cation concentration. The rate of Y z + reduction at pH 7.5 was biphasic with a fast 400 μs phase that suggests binding of Mn 2+ near Y z + at a site that may be one of the native manganese binding sites.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43534/1/11120_2004_Article_BF00048306.pd

    Virtual environments as memory training devices in navigational tasks for older adults.

    Get PDF
    Cognitive training approaches using virtual environments (VEs) might counter age-related visuospatial memory decline and associated difficulties in wayfinding. However, the effects of the visual design of a VE in route learning are not fully understood. Therefore, we created a custom-designed VE optimized for route learning, with adjusted levels of realism and highlighted landmark locations (MixedVE). Herein we tested participants' route recall performance in identifying direction of turn at the intersection with this MixedVE against two baseline alternatives (AbstractVE, RealisticVE). An older vs. a younger group solved the tasks in two stages (immediate vs. delayed recall by one week). Our results demonstrate that the MixedVE facilitates better recall accuracy than the other two VEs for both age groups. Importantly, this pattern persists a week later. Additionally, our older participants were mostly overconfident in their route recall performance, but the MixedVE moderated this potentially detrimental overconfidence. Before the experiment, participants clearly preferred the RealisticVE, whereas after the experiment, most of the younger, and many of the older participants, preferred the MixedVE. Taken together, our findings provide insights into the importance of tailoring visualization design in route learning with VEs. Furthermore, we demonstrate the great potential of the MixedVE and by extension, of similar VEs as memory training devices for route learning, especially for older participants

    New insights into perinatal testicular torsion

    Get PDF
    Perinatal testicular torsion is a relatively rare event that remains unrecognized in many patients or is suspected and treated accordingly only after an avoidable loss of time. The authors report their own experience with several patients, some of them quite atypical but instructive. Missed bilateral torsion is an issue, as are partial torsion, possible antenatal signs, and late presentation. These data are discussed together with the existing literature and may help shed new light on the natural course of testicular torsion and its treatment. The most important conclusion is that a much higher index of suspicion based on clinical findings is needed for timely detection of perinatal torsion. It is the authors’ opinion that immediate surgery is mandatory not only in suspected bilateral torsions but also in cases of possible unilateral torsions. There is no place for a more fatalistic “wait-and-see” approach. Whenever possible, even necrotic testes should not be removed during surgery because some endocrine function may be retained

    Work-to-family enrichment and gender inequalities in eight European countries

    Get PDF
    All social roles have positive and rewarding as well as negative/problematic aspects. Research on the work–family interface has predominantly focused on conflicting roles. In contrast, this paper extends research on work–family enrichment (WFE), a positive aspect of work and gender differences in WFE in a cross-national context. Drawing upon social role theory and the culture sensitive theory on work–family enrichment, we examined gender differences in experiences of developmental WFE in a sample of service sector employees in eight European countries. In line with traditional gender roles, women reported more WFE than men. The relationship was moderated by both an objective and subjective measure of gender egalitarianism but in the opposite direction as hypothesized. The gender gap in WFE was larger in more gender-egalitarian countries, where women may be better able to transfer resources from the work domain to benefit their family role than in low egalitarian societies. National differences in labour market factors, family models and the public discourse on work–life balance mainly explain the unanticipated findings
    corecore