1,550 research outputs found
Multi-risk assessment and management—a comparative study of the current state of affairs in chile and ecuador
In Chile and Ecuador, multiple hazards and dynamic processes in vulnerability pose a high risk. Spatial planning and emergency management can contribute to disaster risk management but they follow different goals. However, global goals, such as from UN-ISDR (United Nat
Search for supersymmetry in events with b-quark jets and missing transverse energy in pp collisions at 7 TeV
Results are presented from a search for physics beyond the standard model
based on events with large missing transverse energy, at least three jets, and
at least one, two, or three b-quark jets. The study is performed using a sample
of proton-proton collision data collected at sqrt(s) = 7 TeV with the CMS
detector at the LHC in 2011. The integrated luminosity of the sample is 4.98
inverse femtobarns. The observed number of events is found to be consistent
with the standard model expectation, which is evaluated using control samples
in the data. The results are used to constrain cross sections for the
production of supersymmetric particles decaying to b-quark-enriched final
states in the context of simplified model spectra.Comment: Submitted to Physical Review
O tratamento contábil do capital intelectual em empresas com valor de mercado superior ao valor contábil
Este artigo tem por objetivo sintetizar o resultado da pesquisa sobre o tratamento contábil que é aplicado ao capital intelectual, sob a ótica do processo de gestão, representado pelos conceitos e técnicas que são utilizados e que dão suporte à ação da administração, em empresas com valor de mercado superior ao valor contábil. Para atingir este propósito, o artigo consubstancia-se em uma pesquisa realizada em duas empresas de capital aberto, de Santa Catarina, que apresentam valor de mercado, considerado o valor das ações superior ao seu valor contábil. Observou-se que, embora as empresas pesquisadas possuam todas as características das organizações voltadas ao conhecimento e domínio tecnológico, o tratamento contábil do capital intelectual é algo ainda muito incipiente, e que, os critérios utilizados para mensurar, registrar e evidenciar as informações referentes ao capital humano, capital estrutural e capital de clientes, com vistas ao processo de gestão, é algo que ainda carece de uma sistematização, para que se possa refletir, por meio das demonstrações contábeis, alguma posição nesse sentido. Concluiu-se que as empresas pesquisadas, mesmo não possuindo as informações sistematizadas sobre as iniciativas de mensuração do capital intelectual, têm consciência da sua importância. No entanto, para que os gestores desses empreendimentos possam, efetivamente, utilizá-las como um diferencial competitivo no processo de gestão, as informações sistematizadas sobre o capital intelectual devem fazer parte dos relatórios gerados para a tomada de decisões.The objective of this article si to summarize the result of the research about the accounting treatment which is applied to the intellectual capital, through the management viewpoint, in companies with a market value superior than the accounting value. In order to reach this intention, the article is substantiated on a research carried out in two open capital companies, in SC, which have a market value, considered the action value superior than its accounting value. It was observed that, although the researched companies have all the characteristics of the organizations that aim to the technological knowledge and domain, the accounting treatment of the intellectual capital is still something too incipient and that the criteria used to measure, register and show up the human capital, structural capital and customer capital referred information with view to the management process, is something that still needs a systematization, so that it is possible to reflect, throughout the accounting demonstrations, some position on this sense. It was concluded that the researched companies, even without the systematized information about the initiative of the intelectual capital mensuration, are conscious about this importance. However, the intellectual capital systematized information must be part of the generated reports for the decion takings, so that the managers of these undertakings can effectively use them as a competitive differential in the management process
Searching for VHE gamma-ray emission associated with IceCube neutrino alerts using FACT, H.E.S.S., MAGIC, and VERITAS
The realtime follow-up of neutrino events is a promising approach to search for astrophysical
neutrino sources. It has so far provided compelling evidence for a neutrino point source: the
flaring gamma-ray blazar TXS 0506+056 was observed in coincidence with the high-energy neutrino IceCube-170922A detected by IceCube. The detection of very-high-energy gamma rays (VHE, E > 100 GeV) from this source helped establish the coincidence and constrained the modeling of the blazar emission at the time of the IceCube event. The four major imaging atmospheric Cherenkov telescope arrays (IACTs) - FACT, H.E.S.S., MAGIC, and VERITAS - operate an active follow-up program of target-of-opportunity observations of neutrino alerts sent by IceCube. This program has two main components. One are the observations of known gamma-ray sources around which a cluster of candidate neutrino events has been identified by IceCube (Gamma-ray Follow-Up, GFU). The second one is the follow-up of single high-energy neutrino candidate events of potential astrophysical origin such as IceCube-170922A. GFU has been recently upgraded by IceCube in collaboration with the IACT groups. We present here recent results from the IACT follow-up programs of IceCube neutrino alerts and a description of the upgraded IceCube GFU system
Search for Continuous and Transient Neutrino Emission Associated with IceCube's Highest-Energy Tracks: An 11-Year Analysis
IceCube alert events are neutrinos with a moderate-to-high probability of
having astrophysical origin. In this study, we analyze 11 years of IceCube data
and investigate 122 alert events and a selection of high-energy tracks detected
between 2009 and the end of 2021. This high-energy event selection (alert
events + high-energy tracks) has an average probability of to be of
astrophysical origin. We search for additional continuous and transient
neutrino emission within the high-energy events' error regions. We find no
evidence for significant continuous neutrino emission from any of the alert
event directions. The only locally significant neutrino emission is the
transient emission associated with the blazar TXS~0506+056, with a local
significance of , which confirms previous IceCube studies. When
correcting for 122 test positions, the global p-value is and is
compatible with the background hypothesis. We constrain the total continuous
flux emitted from all 122 test positions at 100~TeV to be below ~(TeV cm s) at 90% confidence assuming an
spectrum. This corresponds to 4.5% of IceCube's astrophysical diffuse flux.
Overall, we find no indication that alert events, in general, are linked to
lower-energetic continuous or transient neutrino emission.Comment: Accepted by Ap
Search for Extended Sources of Neutrino Emission in the Galactic Plane with IceCube
The Galactic plane, harboring a diffuse neutrino flux, is a particularly
interesting target to study potential cosmic-ray acceleration sites. Recent
gamma-ray observations by HAWC and LHAASO have presented evidence for multiple
Galactic sources that exhibit a spatially extended morphology and have energy
spectra continuing beyond 100 TeV. A fraction of such emission could be
produced by interactions of accelerated hadronic cosmic rays, resulting in an
excess of high-energy neutrinos clustered near these regions. Using 10 years of
IceCube data comprising track-like events that originate from charged-current
muon neutrino interactions, we perform a dedicated search for extended neutrino
sources in the Galaxy. We find no evidence for time-integrated neutrino
emission from the potential extended sources studied in the Galactic plane. The
most significant location, at 2.6 post-trials, is a 1.7 sized
region coincident with the unidentified TeV gamma-ray source 3HWC J1951+266. We
provide strong constraints on hadronic emission from several regions in the
Galaxy.Comment: 13 pages, 4 figures, 5 tables including an appendix. Accepted for
publication in Astrophysical Journa
Searching for eV-scale sterile neutrinos with eight years of atmospheric neutrinos at the IceCube neutrino telescope
We report in detail on searches for eV-scale sterile neutrinos, in the
context of a 3+1 model, using eight years of data from the IceCube neutrino
telescope. By analyzing the reconstructed energies and zenith angles of 305,735
atmospheric and events we construct confidence
intervals in two analysis spaces: vs.
under the conservative assumption ; and
vs. given sufficiently large that
fast oscillation features are unresolvable. Detailed discussions of the event
selection, systematic uncertainties, and fitting procedures are presented. No
strong evidence for sterile neutrinos is found, and the best-fit likelihood is
consistent with the no sterile neutrino hypothesis with a p-value of 8\% in the
first analysis space and 19\% in the second.Comment: This long-form paper is a companion to the letter "An eV-scale
sterile neutrino search using eight years of atmospheric muon neutrino data
from the IceCube Neutrino Observatory". v2: update other experiments contours
on results plo
Measurement of atmospheric neutrino mixing with improved IceCube DeepCore calibration and data processing
We describe a new data sample of IceCube DeepCore and report on the latest measurement of atmospheric neutrino oscillations obtained with data recorded between 2011–2019. The sample includes significant improvements in data calibration, detector simulation, and data processing, and the analysis benefits from a sophisticated treatment of systematic uncertainties, with significantly greater level of detail since our last study. By measuring the relative fluxes of neutrino flavors as a function of their reconstructed energies and arrival directions we constrain the atmospheric neutrino mixing parameters to be sin2θ23=0.51±0.05 and Δm232=2.41±0.07×10−3 eV2, assuming a normal mass ordering. The errors include both statistical and systematic uncertainties. The resulting 40% reduction in the error of both parameters with respect to our previous result makes this the most precise measurement of oscillation parameters using atmospheric neutrinos. Our results are also compatible and complementary to those obtained using neutrino beams from accelerators, which are obtained at lower neutrino energies and are subject to different sources of uncertainties
Searches for Neutrinos from LHAASO ultra-high-energy {\gamma}-ray sources using the IceCube Neutrino Observatory
Galactic PeVatrons are Galactic sources theorized to accelerate cosmic rays
up to PeV in energy. The accelerated cosmic rays are expected to interact
hadronically with nearby ambient gas or the interstellar medium, resulting in
{\gamma}-rays and neutrinos. Recently, the Large High Altitude Air Shower
Observatory (LHAASO) identified 12 {\gamma}-ray sources with emissions above
100 TeV, making them candidates for PeV cosmic-ray accelerators (PeVatrons).
While at these high energies the Klein-Nishina effect suppresses exponentially
leptonic emission from Galactic sources, evidence for neutrino emission would
unequivocally confirm hadronic acceleration. Here, we present the results of a
search for neutrinos from these {\gamma}-ray sources and stacking searches
testing for excess neutrino emission from all 12 sources as well as their
subcatalogs of supernova remnants and pulsar wind nebulae with 11 years of
track events from the IceCube Neutrino Observatory. No significant emissions
were found. Based on the resulting limits, we place constraints on the fraction
of {\gamma}-ray flux originating from the hadronic processes in the Crab Nebula
and LHAASOJ2226+6057
Limits on Neutrino Emission from GRB 221009A from MeV to PeV using the IceCube Neutrino Observatory
Gamma-ray bursts (GRBs) have long been considered a possible source of
high-energy neutrinos. While no correlations have yet been detected between
high-energy neutrinos and GRBs, the recent observation of GRB 221009A - the
brightest GRB observed by Fermi-GBM to date and the first one to be observed
above an energy of 10 TeV - provides a unique opportunity to test for hadronic
emission. In this paper, we leverage the wide energy range of the IceCube
Neutrino Observatory to search for neutrinos from GRB 221009A. We find no
significant deviation from background expectation across event samples ranging
from MeV to PeV energies, placing stringent upper limits on the neutrino
emission from this source.Comment: Version in ApJ Letters Focus on the Ultra-luminous Gamma-Ray Burst
GRB 221009
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