298 research outputs found
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Temporal dynamics of emotional responding: amygdala recovery predicts emotional traits
An individual’s affective style is influenced by many things, including the manner in which an individual responds to an emotional challenge. Emotional response is composed of a number of factors, two of which are the initial reactivity to an emotional stimulus and the subsequent recovery once the stimulus terminates or ceases to be relevant. However, most neuroimaging studies examining emotional processing in humans focus on the magnitude of initial reactivity to a stimulus rather than the prolonged response. In this study, we use functional magnetic resonance imaging to study the time course of amygdala activity in healthy adults in response to presentation of negative images. We split the amygdala time course into an initial reactivity period and a recovery period beginning after the offset of the stimulus. We find that initial reactivity in the amygdala does not predict trait measures of affective style. Conversely, amygdala recovery shows predictive power such that slower amygdala recovery from negative images predicts greater trait neuroticism, in addition to lower levels of likability of a set of social stimuli (neutral faces). These data underscore the importance of taking into account temporal dynamics when studying affective processing using neuroimaging
Can Charisma Be Taught? Tests of Two Interventions
We tested whether we could teach individuals to behave more charismatically, andwhether changes in charisma affected leader outcomes. In Study 1, a mixed-design fieldexperiment, we randomly assigned 34 middle-level managers to a control or anexperimental group. Three months later, we reassessed the managers using theircoworker ratings (Time 1 raters = 343; Time 2 raters = 321). In Study 2, a within-subjectslaboratory experiment, we videotaped 41 MBA participants giving a speech. We thentaught them how to behave more charismatically, and they redelivered the speech6 weeks later. Independent assessors (n = 135) rated the speeches. Results from thestudies indicated that the training had significant effects on ratings of leader charisma(mean D = .62) and that charisma had significant effects on ratings of leaderprototypicality and emergence...............................................................................................................................
SND@LHC: The Scattering and Neutrino Detector at the LHC
SND@LHC is a compact and stand-alone experiment designed to perform measurements with neutrinos produced at the LHC in the pseudo-rapidity region of . The experiment is located 480 m downstream of the ATLAS interaction point, in the TI18 tunnel. The detector is composed of a hybrid system based on an 830 kg target made of tungsten plates, interleaved with emulsion and electronic trackers, also acting as an electromagnetic calorimeter, and followed by a hadronic calorimeter and a muon identification system. The detector is able to distinguish interactions of all three neutrino flavours, which allows probing the physics of heavy flavour production at the LHC in the very forward region. This region is of particular interest for future circular colliders and for very high energy astrophysical neutrino experiments. The detector is also able to search for the scattering of Feebly Interacting Particles. In its first phase, the detector will operate throughout LHC Run 3 and collect a total of 250
Search for 10–1000 GeV Neutrinos from Gamma-Ray Bursts with IceCube
We present the results of a search for 10–1000 GeV neutrinos from 2268 gamma-ray bursts (GRBs) over 8 yr of IceCube-DeepCore data. This work probes burst physics below the photosphere where electromagnetic radiation cannot escape. Neutrinos of tens of giga electronvolts are predicted in sub-photospheric collision of free-streaming neutrons with bulk-jet protons. In a first analysis, we searched for the most significant neutrino-GRB coincidence using six overlapping time windows centered on the prompt phase of each GRB. In a second analysis, we conducted a search for a group of GRBs, each individually too weak to be detectable, but potentially significant when combined. No evidence of neutrino emission is found for either analysis. The most significant neutrino coincidence is for Fermi-GBM GRB bn 140807500, with a p-value of 0.097 corrected for all trials. The binomial test used to search for a group of GRBs had a p-value of 0.65 after all trial corrections. The binomial test found a group consisting only of GRB bn 140807500 and no additional GRBs. The neutrino limits of this work complement those obtained by IceCube at tera electronvolt to peta electronvolt energies. We compare our findings for the large set of GRBs as well as GRB 221009A to the sub-photospheric neutron-proton collision model and find that GRB 221009A provides the most constraining limit on baryon loading. For a jet Lorentz factor of 300 (800), the baryon loading on GRB 221009A is lower than 3.85 (2.13) at a 90% confidence level
Search for Continuous and Transient Neutrino Emission Associated with IceCube’s Highest-energy Tracks: An 11 yr Analysis
Joint searches by FACT, H.E.S.S., MAGIC and VERITAS for VHE gamma-ray emission associated with neutrinos detected by IceCube
The sources of the astrophysical flux of high-energy neutrinos detected by IceCube are still largely unknown, but searches for temporal and spatial correlation between neutrinos and electromagnetic radiation are a promising approach in this endeavor. All major imaging atmospheric Cherenkov telescopes (IACTs) - FACT, H.E.S.S., MAGIC, and VERITAS - operate an active follow-up program of target-of-opportunity observations of neutrino alerts issued by IceCube. These programs use several complementary neutrino alert streams. A publicly distributed alert stream is formed by individual high-energy neutrino candidate events of potentially astrophysical origin, such as IceCube-170922A (which could be linked to the flaring blazar TXS 0506+056). A privately distributed alert stream is formed by clusters of neutrino events in time and space around either pre-selected gamma-ray sources or anywhere in the sky. Here, we present joint searches for multi-wavelength emission associated with a set of IceCube alerts, both private and public, received through mid-January 2021. We will give an overview of the programs of the participating IACTs. We will showcase the various follow-up and data analysis strategies employed in response to the different alert types and various possible counterpart scenarios. Finally, we will present results from a combined analysis of the VHE gamma-ray observations obtained across all involved instruments, as well as relevant multi-wavelength data
Improved modeling of in-ice particle showers for IceCube event reconstruction
The IceCube Neutrino Observatory relies on an array of photomultiplier tubes
to detect Cherenkov light produced by charged particles in the South Pole ice.
IceCube data analyses depend on an in-depth characterization of the glacial
ice, and on novel approaches in event reconstruction that utilize fast
approximations of photoelectron yields. Here, a more accurate model is derived
for event reconstruction that better captures our current knowledge of ice
optical properties. When evaluated on a Monte Carlo simulation set, the median
angular resolution for in-ice particle showers improves by over a factor of
three compared to a reconstruction based on a simplified model of the ice. The
most substantial improvement is obtained when including effects of
birefringence due to the polycrystalline structure of the ice. When evaluated
on data classified as particle showers in the high-energy starting events
sample, a significantly improved description of the events is observed.Comment: 28 pages, 18 figures, 1 table, submitted to JINST, updated to account
for comments receive
Search for an eV-Scale Sterile Neutrino Using Improved High-Energy ν Event Reconstruction in IceCube
Acceptance Tests of more than 10 000 Photomultiplier Tubes for the multi-PMT Digital Optical Modules of the IceCube Upgrade
More than 10,000 photomultiplier tubes (PMTs) with a diameter of 80 mm will
be installed in multi-PMT Digital Optical Modules (mDOMs) of the IceCube
Upgrade. These have been tested and pre-calibrated at two sites. A throughput
of more than 1000 PMTs per week with both sites was achieved with a modular
design of the testing facilities and highly automated testing procedures. The
testing facilities can easily be adapted to other PMTs, such that they can,
e.g., be re-used for testing the PMTs for IceCube-Gen2. Single photoelectron
response, high voltage dependence, time resolution, prepulse, late pulse,
afterpulse probabilities, and dark rates were measured for each PMT. We
describe the design of the testing facilities, the testing procedures, and the
results of the acceptance tests.Comment: 24 pages, 19 figures, 2 tables, submitted to JINS
Measurement of Atmospheric Neutrino Oscillation Parameters Using Convolutional Neural Networks with 9.3 Years of Data in IceCube DeepCore
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