11,895 research outputs found
Situating emotional experience
Psychological construction approaches to emotion suggest that emotional experience is situated and dynamic. Fear, for example, is typically studied in a physical danger context (e.g., threatening snake), but in the real world, it often occurs in social contexts, especially those involving social evaluation (e.g., public speaking). Understanding situated emotional experience is critical because adaptive responding is guided by situational context (e.g., inferring the intention of another in a social evaluation situation vs. monitoring the environment in a physical danger situation). In an fMRI study, we assessed situated emotional experience using a newly developed paradigm in which participants vividly imagine different scenarios from a first-person perspective, in this case scenarios involving either social evaluation or physical danger. We hypothesized that distributed neural patterns would underlie immersion in social evaluation and physical danger situations, with shared activity patterns across both situations in multiple sensory modalities and in circuitry involved in integrating salient sensory information, and with unique activity patterns for each situation type in coordinated large-scale networks that reflect situated responding. More specifically, we predicted that networks underlying the social inference and mentalizing involved in responding to a social threat (in regions that make up the “default mode” network) would be reliably more active during social evaluation situations. In contrast, networks underlying the visuospatial attention and action planning involved in responding to a physical threat would be reliably more active during physical danger situations. The results supported these hypotheses. In line with emerging psychological construction approaches, the findings suggest that coordinated brain networks offer a systematic way to interpret the distributed patterns that underlie the diverse situational contexts characterizing emotional life
A Rigorous Proof of Fermi Liquid Behavior for Jellium Two-Dimensional Interacting Fermions
Using the method of continuous constructive renormalization group around the
Fermi surface, it is proved that a jellium two-dimensional interacting system
of Fermions at low temperature remains analytic in the coupling constant
for where is some numerical constant
and is the temperature. Furthermore in that range of parameters, the first
and second derivatives of the self-energy remain bounded, a behavior which is
that of Fermi liquids and in particular excludes Luttinger liquid behavior. Our
results prove also that in dimension two any transition temperature must be
non-perturbative in the coupling constant, a result expected on physical
grounds. The proof exploits the specific momentum conservation rules in two
dimensions.Comment: 4 pages, no figure
DISTRIBUTION CHOICE UNDER NULL PRIORS AND SMALL SAMPLE SIZE
Defining appropriate probability distributions for the variables in an economic model is an important and often arduous task. This paper evaluates the performance of several common probability distributions under different distributional assumptions when sample sizes are small and there is limited information about the data.Research Methods/ Statistical Methods,
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Effect of a machine learning-based severe sepsis prediction algorithm on patient survival and hospital length of stay: a randomised clinical trial.
IntroductionSeveral methods have been developed to electronically monitor patients for severe sepsis, but few provide predictive capabilities to enable early intervention; furthermore, no severe sepsis prediction systems have been previously validated in a randomised study. We tested the use of a machine learning-based severe sepsis prediction system for reductions in average length of stay and in-hospital mortality rate.MethodsWe conducted a randomised controlled clinical trial at two medical-surgical intensive care units at the University of California, San Francisco Medical Center, evaluating the primary outcome of average length of stay, and secondary outcome of in-hospital mortality rate from December 2016 to February 2017. Adult patients (18+) admitted to participating units were eligible for this factorial, open-label study. Enrolled patients were assigned to a trial arm by a random allocation sequence. In the control group, only the current severe sepsis detector was used; in the experimental group, the machine learning algorithm (MLA) was also used. On receiving an alert, the care team evaluated the patient and initiated the severe sepsis bundle, if appropriate. Although participants were randomly assigned to a trial arm, group assignments were automatically revealed for any patients who received MLA alerts.ResultsOutcomes from 75 patients in the control and 67 patients in the experimental group were analysed. Average length of stay decreased from 13.0 days in the control to 10.3 days in the experimental group (p=0.042). In-hospital mortality decreased by 12.4 percentage points when using the MLA (p=0.018), a relative reduction of 58.0%. No adverse events were reported during this trial.ConclusionThe MLA was associated with improved patient outcomes. This is the first randomised controlled trial of a sepsis surveillance system to demonstrate statistically significant differences in length of stay and in-hospital mortality.Trial registrationNCT03015454
Primary interoceptive cortex activity during simulated experiences of the body
Studies of the classic exteroceptive sensory systems (e.g., vision, touch) consistently demonstrate that
vividly imagining a sensory experience of the world – simulating it – is associated with increased
activity in the corresponding primary sensory cortex. We hypothesized, analogously, that simulating
internal bodily sensations would be associated with increased neural activity in primary interoceptive
cortex. An immersive, language-based mental imagery paradigm was used to test this hypothesis (e.g.,
imagine your heart pounding during a roller coaster ride, your face drenched in sweat during a
workout). During two neuroimaging experiments, participants listened to vividly described situations
and imagined “being there” in each scenario. In Study 1, we observed significantly heightened activity
in primary interoceptive cortex (of dorsal posterior insula) during imagined experiences involving
vivid internal sensations. This effect was specific to interoceptive simulation: it was not observed
during a separate affect focus condition in Study 1, nor during an independent Study 2 that did not
involve detailed simulation of internal sensations (instead involving simulation of other sensory
experiences). These findings underscore the large-scale predictive architecture of the brain and reveal
that words can be powerful drivers of bodily experiences
Analysis of IUE observations of CS in Comet Bradfield (1979 l)
The high resolution rotational band profiles were fitted with theoretical band profiles which are derived using a Boltzmann temperature of 70 K. A very rapid variation with heliocentric distance for the CS brightness was found. The implications of these results for models of the coma along with the origin of the CS species are discussed
Testing the Unitarity of the CKM Matrix with a Space-Based Neutron Decay Experiment
If the Standard Model is correct, and fundamental fermions exist only in the
three generations, then the CKM matrix should be unitary. However, there
remains a question over a deviation from unitarity from the value of the
neutron lifetime. We discuss a simple space-based experiment that, at an orbit
height of 500 km above Earth, would measure the kinetic-energy, solid-angle,
flux spectrum of gravitationally bound neutrons (kinetic energy K<0.606 eV at
this altitude). The difference between the energy spectrum of neutrons that
come up from the Earth's atmosphere and that of the undecayed neutrons that
return back down to the Earth would yield a measurement of the neutron
lifetime. This measurement would be free of the systematics of laboratory
experiments. A package of mass kg could provide a 10^{-3} precision in
two years.Comment: 10 pages, 4 figures. Revised and updated for publicatio
The Fourth Positive System of Carbon Monoxide in the Hubble Space Telescope Spectra of Comets
The rich structure of the Fourth Positive System (A-X) of carbon monoxide
accounts for many of the spectral features seen in long slit HST-STIS
observations of comets 153P/Ikeya-Zhang, C/2001 Q4 (NEAT), and C/2000 WM1
(LINEAR), as well as in the HST-GHRS spectrum of comet C/1996 B2 Hyakutake. A
detailed CO fluorescence model is developed to derive the CO abundances in
these comets by simultaneously fitting all of the observed A-X bands. The model
includes the latest values for the oscillator strengths and state parameters,
and accounts for optical depth effects due to line overlap and self-absorption.
The model fits yield radial profiles of CO column density that are consistent
with a predominantly native source for all the comets observed by STIS. The
derived CO abundances relative to water in these comets span a wide range, from
0.44% for C/2000 WM1 (LINEAR), 7.2% for 153P/Ikeya-Zhang, 8.8% for C/2001 Q4
(NEAT) to 20.9% for C/1996 B2 (Hyakutake). The subtraction of the CO spectral
features using this model leads to the first identification of a molecular
hydrogen line pumped by solar HI Lyman-beta longward of 1200A in the spectrum
of comet 153P/Ikeya-Zhang. (Abridged)Comment: 12 pages, 11 figures, ApJ accepte
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