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 investors’ 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 nématodes entomopathogènes dans des sols horticoles a été étudiée par des prélèvements mensuels en huit sites de Catalogne (nord-est de l'Espagne) pendant 14 mois. Ces nématodes entomopathogènes ont été détectés dans six des huit sites et ont continué à l'être quels qu'aient été les traitements agricoles pratiqués sur ces sites. Pendant cette étude, les sites ont été labourés, détruisant ainsi l'habitat naturel des nématodes, puis laissés en jachère pendant plusieurs mois, sans que la présence des nématodes n'en paraisse affectée. Cependant, une influence saisonnière peut être observée, la présence des nématodes étant plus faible pendant les mois d'été où la température est élevée. Cette influence saisonnière apparaît également affecter la répartition verticale des nématodes qui migrent vers les couches plus profondes du sol, vraisemblablement pour éviter les effets néfastes de la température et du manque d'humidité. Les résultats de cette étude montrent que les populations naturelles de nématodes entomopathogènes sont capables de persister et de survivre dans le sol pendant de longues périodes en s'adaptant aux conditions fluctuantes et adverses de leur habitat naturel. (Résumé 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 shifts’ 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, Spearman’s correlation revealed that the two dimensions of “Self-Transcendence” and “Religion” are moderately involved in the post-traumatic change (specifically, “New Possibilities” ρ =.237, “Personal Strength” ρ =.252, and “Spiritual Change” ρ =.373). Logistic regression failed to show any effect concerning role, shifts’ amount, and distress level. Finally, the monetary incentive appeared to not influence the altruism’s 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