3,847 research outputs found
Half-BPS Geometries and Thermodynamics of Free Fermions
Solutions of type IIB supergravity which preserve half of the supersymmetries
have a dual description in terms of free fermions, as elucidated by the
"bubbling AdS" construction of Lin, Lunin and Maldacena. In this paper we study
the half-BPS geometry associated with a gas of free fermions in thermodynamic
equilibrium obeying the Fermi-Dirac distribution. We consider both regimes of
low and high temperature. In the former case, we present a detailed computation
of the ADM mass of the supergravity solution and find agreement with the
thermal energy of the fermions. The solution has a naked null singularity and,
by general arguments, is expected to develop a finite area horizon once stringy
corrections are included. By introducing a stretched horizon, we propose a way
to match the entropy of the fermions with the entropy of the geometry in the
low temperature regime. In the opposite limit of high temperature, the solution
resembles a dilute gas of D3 branes. Also in this case the ADM mass of the
geometry agrees with the thermal energy of the fermions.Comment: 37 pages, 2 figures, latex; v2: minor corrections, references adde
More supersymmetric Wilson loops
We present a large new family of Wilson loop operators in N=4 supersymmetric
Yang-Mills theory. For an arbitrary curve on the three dimensional sphere one
can add certain scalar couplings to the Wilson loop so it preserves at least
two supercharges. Some previously known loops, notably the 1/2 BPS circle,
belong to this class, but we point out many more special cases which were not
known before and could provide further tests of the AdS/CFT correspondence.Comment: 9 pages, LaTe
Early diagnosis of cardiovascular diseases in workers: role of standard and advanced echocardiography
Cardiovascular disease (CVD) still remains the main cause of morbidity and mortality and consequently early diagnosis is of paramount importance. Working conditions can be regarded as an additional risk factor for CVD. Since different aspects of the job may affect vascular health differently, it is important to consider occupation from multiple perspectives to better assess occupational impacts on health. Standard echocardiography has several targets in the cardiac population, as the assessment of myocardial performance, valvular and/or congenital heart disease, and hemodynamics. Three-dimensional echocardiography gained attention recently as a viable clinical tool in assessing left ventricular (LV) and right ventricular (RV), volume, and shape. Two-dimensional (2DSTE) and, more recently, three-dimensional speckle tracking echocardiography (3DSTE) have also emerged as methods for detection of global and regional myocardial dysfunction in various cardiovascular diseases, and applied to the diagnosis of subtle LV and RV dysfunction. Although these novel echocardiographic imaging modalities have advanced our understanding of LV and RV mechanics, overlapping patterns often show challenges that limit their clinical utility. This review will describe the current state of standard and advanced echocardiography in early detection (secondary prevention) of CVD and address future directions for this potentially important diagnostic strategy
Theoretical investigations of supramolecular chemisorption adducts of volatile small molecules with a trinuclear silver(I) nitrated pyrazolate complex: DFT modeling of dipole-quadrupole interactions
Theoretical investigations of supramolecular chemisorption adducts of volatile small molecules with a trinuclear silver(I) nitrated pyrazolate complex: DFT modeling of dipole-quadrupole interactions
Sammer M Tekarli1, [email protected], Vladimir N Nesterov1, Mohammad A Omary1, Rossana Galassi2, Simone Ricci2, Alfredo Burini2. (1) Department of Chemistry, University of North Texas, Denton, Texas 76203, United States, (2) School of Science and Technology, University of Camerino - Via SantâAgostino, Camerino, Macerata I-62032, Italy
A comparative study on the tendency of a new trinuclear silver(I) pyrazolate, namely [N,N-(3,5-dinitro-pyrazolate)Ag]3 (1) and a similar compound known previously, [N,N-(3,5-bis(trifluoromethyl)pyrazolate)Ag]3 (2) to adsorb small volatile molecules was performed. It was found that 1 has a remarkable tendency to form adducts, at room temperature and atmospheric pressure, with acetone, acetylacetone, ammonia, pyridine, acetonitrile, triethylamine, dimethylsulfide, and tetrahydrothiophene while CO, THF, alcohols, and diethyl ether were not adsorbed. On the contrary, 2 did not undergo adsorption of any of the aforementioned volatile molecules. Density Functional Theory (DFT) results (polarizability, electrostatic potential profiles, kinetics and thermodynamics, and positive point charge calculations) are consistent with the chemisorption model, explain the experimental adsorption selectivity for 1, and the lack of similar adsorption by 2 upon proper selection of the density functional. The M06 method in conjunction with CEP-31G basis set provides good agreement with the experimental data both qualitatively and quantitatively compared to B3LYP/CEP-31G. The results suggest that the adsorption of Lewis basic vapors occurs mainly by kinetic effects. The high vs. low binding energies calculated for the adducts of 1 with acetonitrile vs. CO manifest the experimental findings. The findings in this project suggest that this class of quadrupolar macromolecular complexes may exhibit potential for toxic industrial chemical (TIC) removal applications already known for porous organic polymers
Incremental Object-Based Novelty Detection with Feedback Loop
Object-based Novelty Detection (ND) aims to identify unknown objects that do
not belong to classes seen during training by an object detection model. The
task is particularly crucial in real-world applications, as it allows to avoid
potentially harmful behaviours, e.g. as in the case of object detection models
adopted in a self-driving car or in an autonomous robot. Traditional approaches
to ND focus on one time offline post processing of the pretrained object
detection output, leaving no possibility to improve the model robustness after
training and discarding the abundant amount of out-of-distribution data
encountered during deployment.
In this work, we propose a novel framework for object-based ND, assuming that
human feedback can be requested on the predicted output and later incorporated
to refine the ND model without negatively affecting the main object detection
performance. This refinement operation is repeated whenever new feedback is
available. To tackle this new formulation of the problem for object detection,
we propose a lightweight ND module attached on top of a pre-trained object
detection model, which is incrementally updated through a feedback loop. We
also propose a new benchmark to evaluate methods on this new setting and test
extensively our ND approach against baselines, showing increased robustness and
a successful incorporation of the received feedback
Quality of life in workers and stress: gender differences in exposure to psychosocial risks and perceived well-being
Background. Quality of working life is the result of many factors inherent in the workplace environment, especially in terms of
exposure to psychosocial risks. Objectives. The purpose of this study is to assess the quality of life with special attention to gender
differences. Methods. The HSE-IT questionnaire and the WHO-5 Well-Being Index were administered to a group of workers (74
males and 33 females). The authors also used Cronbachâs alpha test to assess the internal consistency of both questionnaires and the
MannâWhitney test to evaluate the significance of gender differences in both questionnaires. Results. The HSE-IT highlighted the
existence of work-related stress in all the population with a critical perception regarding the domain âRelationships.â Furthermore,
gender analysis highlighted the presence of two additional domains in the female population: âDemandâ ( = 0,002) and âSupport
from Managersâ ( = 0,287). The WHO-5 highlighted a well-being level below the standard cut-off point with a significant gender
difference ( = 0.009) for males (18, SD = 6) as compared to females (14, SD = 6,4). Cronbachâs alpha values indicated a high level of
internal consistency for both of our scales. Conclusions. The risk assessment of quality of working life should take into due account
the individual characteristics of workers, with special attention to gender
Exploring the economic contribution of copyright-intensive industries in Italy
Purpose In the last few years, a number of studies documented the economic impact of copyright in different national economies. The purpose of this paper is to contribute to increase these studies based on the assess of the economic impact of copyright-intensive industries in Italy. Design/methodology/approach Consistent with prior studies, this paper attempts to measure the impact of copyright on GDP and employment. In doing so, two different methodologies are applied: (1) WIPOâs guidelines âWipo Guide on surveying the Economic Contribution of the Copyright-Based Industriesâ and (2) the Ernest & Young study entitled: â1 er Panorama des Industries Culturelles et CrĂ©atives. Au Couer du Rayonnement et de la CompetitivitĂ© de la Franceâ. The selected year for the survey is 2011. The main source data are collected by statistic databases like Istat, Eurostat and United Nations Statistics Division. The industrial classification starts with the International Standard Industrial Classification suggested in the WIPO Guide and, after the conversion, first in NACE and then in ATECO 2007, we identify the industries and their activities as relevant to copyright-based industries in Italy. Findings The results of our analysis support the thesis that copyright has a great impact on the aspects of economic growth, of the labour market and on the country development. Originality/value This study compares the classification and the methods used for determination of the economic impact of copyright-intensive industries. Practical implications By assessing the economic impact of this sector on Italian GDP, this paper raises awareness about the role and importance of such industries to the Italian economy
In silico screening of nanoporous materials for urea removal in hemodialysis applications
The design of miniaturized hemodialysis devices, such as wearable artificial kidneys, requires regeneration of the dialysate stream to remove uremic toxins from water. Adsorption has the potential to capture such molecules, but conventional adsorbents have low urea/water selectivity. In this work,
we performed a comprehensive computational study of 560 porous crystalline adsorbents comprising mainly covalent organic frameworks (COFs), as well as some siliceous zeolites, metal organic frameworks (MOFs) and graphitic materials. An initial screening using Widom insertion method assessed
the excess chemical potential at infinite dilution for water and urea at 310 K, providing information on the strength and selectivity of urea adsorption. From such analysis it was observed that urea adsorption and urea/water selectivity increased strongly with fluorine content in COFs, while other compositional or
structural parameters did not correlate with material performance. Two COFs, namely COF-F6 and Tf-DHzDPr were explored further through Molecular Dynamics simulations. The results agree with those of the Widom method and allow to identify the urea binding sites, the contribution of electrostatic and van der Waals interactions, and the position of preferential ureaâurea and ureaâframework interactions. This study paves the way for a well-informed experimental campaign and accelerates the development of novel sorbents for urea removal, ultimately advancing on the path to achieve wearable artificial kidneys
Dataset on the use of 3D speckle tracking echocardiography in light-chain amyloidosis
The dataset presented in this article is related to the research article entitled âBiventricular assessment of light-chain amyloidosis using 3D speckle tracking echocardiography: Differentiation from other forms of myocardial hypertrophyâ (Vitarelli et al.,2018) [1], which examined the potential utility of left ventricular (LV) and right ventricular (RV) deformation and rotational parameters derived from three-dimensional speckle-tracking echocardiography (3DSTE) to diagnose cardiac amyloidosis(CA) and differentiate this disease from other forms of myocardial hypertrophy. The combined assessment of LV basal longitudinal strain, LV basal rotation and RV basal longitudinal strain had a high discriminative power for detecting CA. The data of this study provides more understanding on the value of LV 3DSTE deformation parameters as well as RV parameters in this particular cardiomyopathy
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