58 research outputs found

    Probing strongly coupled anisotropic plasma

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    We calculate the static potential, the drag force and the jet quenching parameter in strongly coupled anisotropic N=4 super Yang-Mills plasma. We find that the jet quenching is in general enhanced in presence of anisotropy compared to the isotropic case and that its value depends strongly on the direction of the moving quark and the direction along which the momentum broadening occurs. The jet quenching is strongly enhanced for a quark moving along the anisotropic direction and momentum broadening happens along the transverse one. The parameter gets lower for a quark moving along the transverse direction and the momentum broadening considered along the anisotropic one. Finally, a weaker enhancement is observed when the quark moves in the transverse plane and the broadening occurs on the same plane. The drag force for quark motion parallel to the anisotropy is always enhanced. For motion in the transverse space the drag force is enhanced compared to the isotropic case only for quarks having velocity above a critical value. Below this critical value the force is decreased. Moreover, the drag force along the anisotropic direction is always stronger than the force in the transverse space. The diffusion time follows exactly the inverse relations of the drag forces. The static potential is decreased and stronger decrease observed for quark-antiquark pair aligned along the anisotropic direction than the transverse one. We finally comment on our results and elaborate on their similarities and differences with the weakly coupled plasmas.Comment: 1+44 pages, 18 Figures; Added results on static force; Added references; version published in JHE

    Thermodynamic instability of doubly spinning black objects

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    We investigate the thermodynamic stability of neutral black objects with (at least) two angular momenta. We use the quasilocal formalism to compute the grand canonical potential and show that the doubly spinning black ring is thermodynamically unstable. We consider the thermodynamic instabilities of ultra-spinning black objects and point out a subtle relation between the microcanonical and grand canonical ensembles. We also find the location of the black string/membrane phases of doubly spinning black objects.Comment: 25 pages, 7 figures v2: matches the published versio

    Moduli and electromagnetic black brane holography

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    We investigate the thermodynamic and hydrodynamic properties of 4-dimensional gauge theories with finite electric charge density in the presence of a constant magnetic field. Their gravity duals are planar magnetically and electrically charged AdS black holes in theories that contain a gauge Chern-Simons term. We present a careful analysis of the near horizon geometry of these black branes at finite and zero temperature for the case of a scalar field non-minimally coupled to the electromagnetic field. With the knowledge of the near horizon data, we obtain analytic expressions for the shear viscosity coefficient and entropy density, and also study the effect of a generic set of four derivative interactions on their ratio. We also comment on the attractor flows of the extremal solutions.Comment: 39 pages, no figures; v2: minor changes, refs. added; v3: typo fixed; v4: a proof for decoupling of the viscosity mode added in appendix, matches the published versio

    QGP Theory: Status and Perspectives

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    The current status of Quark-Gluon-Plasma Theory is reviewed. Special emphasis is placed on QGP signatures, the interpretation of current data and what to expect from RHIC in the near future.Comment: 20 pages, invited overview talk at the 4th International Conference on the Physcis and Astrophysics of the Quark-Gluon-Plasma, November 2001, Jaipur, India, to appear in Praman

    Surfing the internet for health information: an italian survey on use and population choices

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    BACKGROUND: Recent international sources have described how the rapid expansion of the Internet has precipitated an increase in its use by the general population to search for medical information. Most studies on e-health use investigated either through the prevalence of such use and the social and income patterns of users in selected populations, or the psychological consequences and satisfaction experienced by patients with particular diseases. Few studies have been carried out in Europe that have tried to identify the behavioral consequences of Internet use for health-related purposes in the general population.The aims of this study are to provide information about the prevalence of Internet use for health-related purposes in Italy according to demographic and socio-cultural features, to investigate the impact of the information found on health-related behaviors and choices and to analyze any differences based on health condition, self-rated health and relationships with health professionals and facilities. METHODS: A multicenter survey was designed within six representative Italian cities. Data were collected through a validated questionnaire administered in hospital laboratories by physicians. Respondents were questioned about their generic condition, their use of the Internet and their health behaviors and choices related to Internet use. Data were analyzed using descriptive statistics and logistic regression to assess any differences by socio-demographic and health-related variables. RESULTS: The sample included 3018 individuals between the ages of 18 and 65 years. Approximately 65% of respondents reported using the Internet, and 57% of them reported using it to search for health-related information. The main reasons for search on the Internet were faster access and a greater amount of information. People using the Internet more for health-related purposes were younger, female and affected by chronic diseases. CONCLUSIONS: A large number of Internet users search for health information and subsequently modify their health behaviors and relationships with their medical providers. This may suggest a strong public health impact with consequences in all European countries, and it would be prudent to plan educational and prevention programs. However, it could be important to investigate the quality of health-related websites to protect and inform user

    The Airway Microbiota in Cystic Fibrosis: A Complex Fungal and Bacterial Community—Implications for Therapeutic Management

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    International audienceBackground Given the polymicrobial nature of pulmonary infections in patients with cystic fibrosis (CF), it is essential to enhance our knowledge on the composition of the microbial community to improve patient management. In this study, we developed a pyrosequencing approach to extensively explore the diversity and dynamics of fungal and prokaryotic populations in CF lower airways. Methodology and Principal Findings Fungi and bacteria diversity in eight sputum samples collected from four adult CF patients was investigated using conventional microbiological culturing and high-throughput pyrosequencing approach targeting the ITS2 locus and the 16S rDNA gene. The unveiled microbial community structure was compared to the clinical profile of the CF patients. Pyrosequencing confirmed recently reported bacterial diversity and observed complex fungal communities, in which more than 60% of the species or genera were not detected by cultures. Strikingly, the diversity and species richness of fungal and bacterial communities was significantly lower in patients with decreased lung function and poor clinical status. Values of Chao1 richness estimator were statistically correlated with values of the Shwachman-Kulczycki score, body mass index, forced vital capacity, and forced expiratory volume in 1 s (p = 0.046, 0.047, 0.004, and 0.001, respectively for fungal Chao1 indices, and p = 0.010, 0.047, 0.002, and 0.0003, respectively for bacterial Chao1 values). Phylogenetic analysis showed high molecular diversities at the sub-species level for the main fungal and bacterial taxa identified in the present study. Anaerobes were isolated with Pseudomonas aeruginosa, which was more likely to be observed in association with Candida albicans than with Aspergillus fumigatus

    Molecular mechanisms of cell death: recommendations of the Nomenclature Committee on Cell Death 2018.

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    Over the past decade, the Nomenclature Committee on Cell Death (NCCD) has formulated guidelines for the definition and interpretation of cell death from morphological, biochemical, and functional perspectives. Since the field continues to expand and novel mechanisms that orchestrate multiple cell death pathways are unveiled, we propose an updated classification of cell death subroutines focusing on mechanistic and essential (as opposed to correlative and dispensable) aspects of the process. As we provide molecularly oriented definitions of terms including intrinsic apoptosis, extrinsic apoptosis, mitochondrial permeability transition (MPT)-driven necrosis, necroptosis, ferroptosis, pyroptosis, parthanatos, entotic cell death, NETotic cell death, lysosome-dependent cell death, autophagy-dependent cell death, immunogenic cell death, cellular senescence, and mitotic catastrophe, we discuss the utility of neologisms that refer to highly specialized instances of these processes. The mission of the NCCD is to provide a widely accepted nomenclature on cell death in support of the continued development of the field
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