729 research outputs found

    Intoxicated eyewitnesses:the effect of a fully balanced placebo design on event memory and metacognitive control

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    Few studies have examined the impact of alcohol on metacognition for witnessed events. We used a 2x2 balanced placebo design, where mock-witnesses expected and drank alcohol, did not expect but drank alcohol, did not expect nor drank alcohol, or expected but did not drink alcohol. Participants watched a mock-crime in a bar-lab, followed by free recall and a cued-recall test with or without the option to reply ‘don’t know’ (DK). Intoxicated mock-witnesses’ free recall was less complete but not less accurate. During cued-recall, alcohol led to lower accuracy, and reverse placebo participants gave more erroneous and fewer correct responses. Permitting and clarifying DK responses was associated with fewer errors and more correct responses for sober individuals; and intoxicated witnesses were less likely to opt out of erroneous responding to unanswerable questions. Our findings highlight the practical and theoretical importance of examining pharmacological effects of alcohol and expectancies in real-life settings

    Average stresses and force fluctuations in non-cohesive granular materials

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    A lattice model is presented for investigating the fluctuations in static granular materials under gravitationally induced stress. The model is similar in spirit to the scalar q-model of Coppersmith et al., but ensures balance of all components of forces and torques at each site. The geometric randomness in real granular materials is modeled by choosing random variables at each site, consistent with the assumption of cohesionless grains. Configurations of the model can be generated rapidly, allowing the statistical study of relatively large systems. For a 2D system with rough walls, the model generates configurations consistent with continuum theories for the average stresses (unlike the q-model) without requiring the assumption of a constitutive relation. For a 2D system with periodic boundary conditions, the model generates single-grain force distributions similar to those obtained from the q-model with a singular distribution of q's.Comment: 18 pages, 10 figures. Uses aps,epsfig,graphicx,floats,revte

    Particle Systems with Stochastic Passing

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    We study a system of particles moving on a line in the same direction. Passing is allowed and when a fast particle overtakes a slow particle, it acquires a new velocity drawn from a distribution P_0(v), while the slow particle remains unaffected. We show that the system reaches a steady state if P_0(v) vanishes at its lower cutoff; otherwise, the system evolves indefinitely.Comment: 5 pages, 5 figure

    Quantum Collective Creep: a Quasiclassical Langevin Equation Approach

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    The dynamics of an elastic medium driven through a random medium by a small applied force is investigated in the low-temperature limit where quantum fluctuations dominate. The motion proceeds via tunneling of segments of the manifold through barriers whose size grows with decreasing driving force ff. In the limit of small drive, at zero-temperature the average velocity has the form vexp[const./αfμ]v\propto\exp[-{\rm const.}/\hbar^{\alpha} f^{\mu}]. For strongly dissipative dynamics, there is a wide range of forces where the dissipation dominates and the velocity--force characteristics takes the form vexp[S(f)/]v\propto\exp[-S(f)/\hbar], with S(f)1/f(d+2ζ)/(2ζ)S(f)\propto 1/ f^{(d+2\zeta)/(2-\zeta)} the action for a typical tunneling event, the force dependence being determined by the roughness exponent ζ\zeta of the dd-dimensional manifold. This result agrees with the one obtained via simple scaling considerations. Surprisingly, for asymptotically low forces or for the case when the massive dynamics is dominant, the resulting quantum creep law is {\it not} of the usual form with a rate proportional to exp[S(f)/]\exp[-S(f)/\hbar]; rather we find vexp{[S(f)/]2}v\propto \exp\{-[S(f)/\hbar]^2\} corresponding to α=2\alpha=2 and μ=2(d+2ζ1)/(2ζ)\mu= 2(d+2\zeta-1)/(2-\zeta), with μ/2\mu/2 the naive scaling exponent for massive dynamics. Our analysis is based on the quasi-classical Langevin approximation with a noise obeying the quantum fluctuation--dissipation theorem. The many space and time scales involved in the dynamics are treated via a functional renormalization group analysis related to that used previously to treat the classical dynamics of such systems. Various potential difficulties with these approaches to the multi-scale dynamics -- both classical and quantum -- are raised and questions about the validity of the results are discussed.Comment: RevTeX, 30 pages, 8 figures inserte

    Phase transitions in the antiferromagnetic XY model with a kagome lattice

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    The ground state of the antiferromagnetic XY model with a kagome lattice is characterized by a well developed accidental degeneracy. As a consequence the phase transition in this system consists in unbinding of pairs of fractional vortices. Addition of the next-to-nearest neighbors (NNN) interaction leads to stabilization of the long-range order in chirality (staggered chirality). We show that the phase transition, related with destruction of this long-range order, can happen as a separate phase transition below the temperature of the fractional vortex pairs unbinding only if the NNN coupling is extremely weak, and find how the temperature of this transition depends on coupling constants. We also demonstarte that the antiferromagnetic ordering of chiralities and, accordingly, the presence of the second phase transition are induced by the free energy of spin wave fluctuations even in absence of the NNN coupling.Comment: 10 pages (Revtex) + 8 figures (in 2 postscript files

    The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3)

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    IMPORTANCE: Definitions of sepsis and septic shock were last revised in 2001. Considerable advances have since been made into the pathobiology (changes in organ function, morphology, cell biology, biochemistry, immunology, and circulation), management, and epidemiology of sepsis, suggesting the need for reexamination. OBJECTIVE: To evaluate and, as needed, update definitions for sepsis and septic shock. PROCESS: A task force (n = 19) with expertise in sepsis pathobiology, clinical trials, and epidemiology was convened by the Society of Critical Care Medicine and the European Society of Intensive Care Medicine. Definitions and clinical criteria were generated through meetings, Delphi processes, analysis of electronic health record databases, and voting, followed by circulation to international professional societies, requesting peer review and endorsement (by 31 societies listed in the Acknowledgment). KEY FINDINGS FROM EVIDENCE SYNTHESIS: Limitations of previous definitions included an excessive focus on inflammation, the misleading model that sepsis follows a continuum through severe sepsis to shock, and inadequate specificity and sensitivity of the systemic inflammatory response syndrome (SIRS) criteria. Multiple definitions and terminologies are currently in use for sepsis, septic shock, and organ dysfunction, leading to discrepancies in reported incidence and observed mortality. The task force concluded the term severe sepsis was redundant. RECOMMENDATIONS: Sepsis should be defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. For clinical operationalization, organ dysfunction can be represented by an increase in the Sequential [Sepsis-related] Organ Failure Assessment (SOFA) score of 2 points or more, which is associated with an in-hospital mortality greater than 10%. Septic shock should be defined as a subset of sepsis in which particularly profound circulatory, cellular, and metabolic abnormalities are associated with a greater risk of mortality than with sepsis alone. Patients with septic shock can be clinically identified by a vasopressor requirement to maintain a mean arterial pressure of 65 mm Hg or greater and serum lactate level greater than 2 mmol/L (>18 mg/dL) in the absence of hypovolemia. This combination is associated with hospital mortality rates greater than 40%. In out-of-hospital, emergency department, or general hospital ward settings, adult patients with suspected infection can be rapidly identified as being more likely to have poor outcomes typical of sepsis if they have at least 2 of the following clinical criteria that together constitute a new bedside clinical score termed quickSOFA (qSOFA): respiratory rate of 22/min or greater, altered mentation, or systolic blood pressure of 100 mm Hg or less. CONCLUSIONS AND RELEVANCE: These updated definitions and clinical criteria should replace previous definitions, offer greater consistency for epidemiologic studies and clinical trials, and facilitate earlier recognition and more timely management of patients with sepsis or at risk of developing sepsis

    On defining the Hamiltonian beyond quantum theory

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    Energy is a crucial concept within classical and quantum physics. An essential tool to quantify energy is the Hamiltonian. Here, we consider how to define a Hamiltonian in general probabilistic theories, a framework in which quantum theory is a special case. We list desiderata which the definition should meet. For 3-dimensional systems, we provide a fully-defined recipe which satisfies these desiderata. We discuss the higher dimensional case where some freedom of choice is left remaining. We apply the definition to example toy theories, and discuss how the quantum notion of time evolution as a phase between energy eigenstates generalises to other theories.Comment: Authors' accepted manuscript for inclusion in the Foundations of Physics topical collection on Foundational Aspects of Quantum Informatio

    A systematic review on the relationship between self-esteem and interrogative suggestibility

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    Some factors, such as age, learning disability and mental health difficulties, have been identified as making police suspects more vulnerable to suggestibility and false confessions during interview. However, there has been no systematic review on the association between self-esteem and suggestibility. Seven electronic bibliographic databases and reference lists of previous literature reviews of suggestibility in children were searched. Selected studies were quality assessed using pre-defined criteria before data were extracted. Electronic searches yielded 1914 hits. Of these, 685 duplicates, 1181 irrelevant references and 39 references that did not meet the inclusion criteria were removed. Nine publications were included in the review. Significant correlations between self-esteem and suggestibility, most notably on the Yield 1 subscale of the GSS, were found but four of the nine studies found no significant correlation. The prevalent use of self-report measures and lack of clarity in defining self-esteem limit the validity of those studies

    Quantizing Charged Magnetic Domain Walls: Strings on a Lattice

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    The discovery by Tranquada et al. of an ordered phase of charged domain walls in the high-Tc cuprates leads us to consider the possible existence of a quantum domain-wall liquid. We propose minimal models for the quantization, by meandering fluctuations, of isolated charged domain walls. These correspond to lattice string models. The simplest model of this kind, a directed lattice string, can be mapped onto a quantum spin chain or on a classical two-dimensional solid-on-solid surface model. The model exhibits a rich phase diagram, containing several rough phases with low-lying excitations as well as ordered phases which are gapped.Comment: 4 two-column pages, including the 3 Postscript figure

    GCOM-W AMSR2 Soil Moisture Product Validation Using Core Validation Sites

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    The Advanced Microwave Scanning Radiometer 2 (AMSR2) is part of the Global Change Observation Mission-Water (GCOM-W). AMSR2 has filled the gap in passive microwave observations left by the loss of the Advanced Microwave Scanning RadiometerEarth Observing System (AMSR-E) after almost 10 years of observations. Both missions provide brightness temperature observations that are used to retrieve soil moisture estimates at the near surface. A merged AMSR-E and AMSR2 data product will help build a consistent long-term dataset; however, before this can be done, it is necessary to conduct a thorough validation and assessment of the AMSR2 soil moisture products. This study focuses on the validation of the AMSR2 soil moisture products by comparison with in situ reference data from a set of core validation sites around the world. A total of three soil moisture products that rely on different algorithms were evaluated; the Japan Aerospace Exploration Agency (JAXA) soil moisture algorithm, the Land Parameter Retrieval Model (LPRM), and the Single Channel Algorithm (SCA). JAXA, SCA and LPRM soil moisture estimates capture the overall climatological features. The spatial features of the three products have similar overall spatial structure. The JAXA soil moisture product shows a lower dynamic range in the retrieved soil moisture with a satisfactory performance matrix when compared to in situ observations (ubRMSE0.059 m3m3, Bias-0.083 m3m3, R0.465). The SCA performs well over low and moderately vegetated areas (ubRMSE0.053 m3m3, Bias-0.039 m3m3, R0.549). The LPRM product has a large dynamic range compared to in situ observations with a wet bias (ubRMSE0.094 m3m3, Bias0.091 m3m3, R0.577). Some of the error is due to the difference in observation depth between the in situ sensors (5 cm) and satellite estimates (1 cm). Results indicate that overall the JAXA and SCA have the best performance based upon the metrics considered
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