6,427 research outputs found
Entanglement detection in coupled particle plasmons
When in close contact, plasmonic resonances interact and become strongly
correlated. In this work we develop a quantum mechanical model, using the
language of continuous variables and quantum information, for an array of
coupled particle plasmons. This model predicts that when the coupling strength
between plasmons approaches or surpasses the local dissipation, a sizable
amount of entanglement is stored in the collective modes of the array. We also
prove that entanglement manifests itself in far-field images of the plasmonic
modes, through the statistics of the quadratures of the field, in what
constitutes a novel family of entanglement witnesses. This protocol is so
robust that it is indeed independent of whether our own model is correct.
Finally, we estimate the amount of entanglement, the coupling strength and the
correlation properties for a system that consists of two or more coupled
nanospheres of silver, showing evidence that our predictions could be tested
using present-day state-of-the-art technology.Comment: 8 pages (6 main text + 2 supplemental), 3 figure
Analysis into the Effect the Sarbanes-Oxley Act of 2002 has had on Investor Confidence in Audited Financial Statements
This paper studies the impact that the Sarbanes-Oxley Act of 2002 (SOX) has had on investor confidence in audited financial statements. Most studies of SOX examined its effect on audit quality, but the principal goal that government officials wanted to accomplish was to restore investor confidence in audited financial information following the frauds at Enron, WorldCom, and other public companies. The main method used in gathering data is a small survey to investors, where they answered questions regarding certain parts of SOX to gain insights into investorsâ perspectives. After analyzing the survey results as well as researching scholarly works on other key sections in SOX, it has been determined that SOX has had a significant impact on investor confidence in audited financial statements. Certain sections have stronger impacts than others, and can be used by public companies to appeal better to investors
Mapping the structural diversity of C60 carbon clusters and their infrared spectra
The current debate about the nature of the carbonaceous material carrying the
infrared (IR) emission spectra of planetary and proto-planetary nebulae,
including the broad plateaus, calls for further studies on the interplay
between structure and spectroscopy of carbon-based compounds of astrophysical
interest. The recent observation of C60 buckminsterfullerene in space suggests
that carbon clusters of similar size may also be relevant. In the present work,
broad statistical samples of C60 isomers were computationally determined
without any bias using a reactive force field, their IR spectra being
subsequently obtained following local optimization with the
density-functional-based tight-binding theory. Structural analysis reveals four
main structural families identified as cages, planar polycyclic aromatics,
pretzels, and branched. Comparison with available astronomical spectra
indicates that only the cage family could contribute to the plateau observed in
the 6-9 micron region. The present framework shows great promise to explore and
relate structural and spectroscopic features in more diverse and possibly
hydrogenated carbonaceous compounds, in relation with astronomical
observations
Galactic Outflows and the pollution of the Galactic Environment by Supernovae
We here explore the effects of the SN explosions into the environment of
star-forming galaxies like the Milky Way. Successive randomly distributed and
clustered SNe explosions cause the formation of hot superbubbles that drive
either fountains or galactic winds above the galactic disk, depending on the
amount and concentration of energy that is injected by the SNe. In a galactic
fountain, the ejected gas is re-captured by the gravitational potential and
falls back onto the disk. From 3D nonequilibrium radiative cooling
hydrodynamical simulations of these fountains, we find that they may reach
altitudes up to about 5 kpc in the halo and thus allow for the formation of the
so called intermediate-velocity-clouds (IVCs) which are often observed in the
halos of disk galaxies. The high-velocity-clouds that are also observed but at
higher altitudes (of up to 12 kpc) require another mechanism to explain their
production. We argue that they could be formed either by the capture of gas
from the intergalactic medium and/or by the action of magnetic fields that are
carried to the halo with the gas in the fountains. Due to angular momentum
losses to the halo, we find that the fountain material falls back to smaller
radii and is not largely spread over the galactic disk. Instead, the SNe ejecta
fall nearby the region where the fountain was produced, a result which is
consistent with recent chemical models of the galaxy. The fall back material
leads to the formation of new generations of molecular clouds and to supersonic
turbulence feedback in the disk.Comment: 10 pages, 5 figures; paper of invited talk for the Procs. of the 2007
WISER Workshop (World Space Environment Forum), Alexandria, Egypt, October
2007, Spa. Sci. Rev
Temporal study of natural populations of Heterorhabditid and Steinernematid nematodes in horticultural crop soils
La dynamique des populations de nĂ©matodes entomopathogĂšnes dans des sols horticoles a Ă©tĂ© Ă©tudiĂ©e par des prĂ©lĂšvements mensuels en huit sites de Catalogne (nord-est de l'Espagne) pendant 14 mois. Ces nĂ©matodes entomopathogĂšnes ont Ă©tĂ© dĂ©tectĂ©s dans six des huit sites et ont continuĂ© Ă l'ĂȘtre quels qu'aient Ă©tĂ© les traitements agricoles pratiquĂ©s sur ces sites. Pendant cette Ă©tude, les sites ont Ă©tĂ© labourĂ©s, dĂ©truisant ainsi l'habitat naturel des nĂ©matodes, puis laissĂ©s en jachĂšre pendant plusieurs mois, sans que la prĂ©sence des nĂ©matodes n'en paraisse affectĂ©e. Cependant, une influence saisonniĂšre peut ĂȘtre observĂ©e, la prĂ©sence des nĂ©matodes Ă©tant plus faible pendant les mois d'Ă©tĂ© oĂč la tempĂ©rature est Ă©levĂ©e. Cette influence saisonniĂšre apparaĂźt Ă©galement affecter la rĂ©partition verticale des nĂ©matodes qui migrent vers les couches plus profondes du sol, vraisemblablement pour Ă©viter les effets nĂ©fastes de la tempĂ©rature et du manque d'humiditĂ©. Les rĂ©sultats de cette Ă©tude montrent que les populations naturelles de nĂ©matodes entomopathogĂšnes sont capables de persister et de survivre dans le sol pendant de longues pĂ©riodes en s'adaptant aux conditions fluctuantes et adverses de leur habitat naturel. (RĂ©sumĂ© d'auteur
The Role of Life Meaning in Psychological Distress and Post-traumatic Growth Among Italian First-Aid Volunteers During the COVID-19 Outbreak
The coronavirus disease 2019 (COVID-19) pandemic has been a sudden and disruptive event that has produced lots of deaths, overload of the healthcare system, interruption of social habits, and change in life prospective. The study aimed to explore the relationships between meaning of life, psychological distress, and post-traumatic growth in volunteers from the first-aid associations operating in Italy belonging to the areas most affected by the pandemic (Bergamo, Brescia, and Parma). Our hypothesis anticipated that the meaning of life can mediate the relationship between psychological distress and post-traumatic growth. We, also, expected that this effect could vary with the role played in the rescue team, the increased shiftsâ amount, and the monetary incentive. Using a cross-sectional design, a convenience sample of 268 consenting participants completed Depression, Anxiety and Stress Scale (DASS-21), Post-Traumatic Growth Inventory (PTGI), and Personal Meaningful Profile-Brief (PMP-B). Findings yielded a positive relationship between psychological distress and post-traumatic growth (r =.284). Regarding the meaning of life, Spearmanâs correlation revealed that the two dimensions of âSelf-Transcendenceâ and âReligionâ are moderately involved in the post-traumatic change (specifically, âNew Possibilitiesâ Ï =.237, âPersonal Strengthâ Ï =.252, and âSpiritual Changeâ Ï =.373). Logistic regression failed to show any effect concerning role, shiftsâ amount, and distress level. Finally, the monetary incentive appeared to not influence the altruismâs propension. Even though our findings should be interpreted with caution, this study provides evidence for the relevance of meaning of life to understanding of resilience and promoting the well-being of workforce following traumatic experiences
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