433 research outputs found

    Review on possible gravitational anomalies

    Full text link
    This is an updated introductory review of 2 possible gravitational anomalies that has attracted part of the Scientific community: the Allais effect that occur during solar eclipses, and the Pioneer 10 spacecraft anomaly, experimented also by Pioneer 11 and Ulysses spacecrafts. It seems that, to date, no satisfactory conventional explanation exist to these phenomena, and this suggests that possible new physics will be needed to account for them. The main purpose of this review is to announce 3 other new measurements that will be carried on during the 2005 solar eclipses in Panama and Colombia (Apr. 8) and in Portugal (Oct.15).Comment: Published in 'Journal of Physics: Conferences Series of the American Institute of Physics'. Contribution for the VI Mexican School on Gravitation and Mathematical Physics "Approaches to Quantum Gravity" (Playa del Carmen, Quintana Roo, Mexico, Nov. 21-27, 2004). Updates to this information will be posted in http://www.lsc-group.phys.uwm.edu/~xavier.amador/anomalies.htm

    Self-medication for migraine: a Nationwide cross-sectional study in Italy

    Get PDF
    Headache disorders are considered the second leading cause of years lived with disability worldwide, and 90% of people have a headache episode at least once a year, thus representing a relevant public health priority. As the pharmacist is often the first and only point of reference for people complaining of headache, we carried out a survey in a nationwide sample of Italian pharmacies, in order to describe the distribution of migraine or non-migraine type headaches and medicines overuse among people entering pharmacies seeking for self-medication; and to evaluate the association, in particular of migraine, with socio-demographic and clinical characteristics, and with the pathway of care followed by the patients. A 14-item questionnaire, including socio-demographic and clinical factors, was administered by trained pharmacists to subjects who entered a pharmacy requesting self-medication for a headache attack. The ID Migraine™ Screener was used to classify headache sufferers in four classes. From June 2016 to January 2017, 4424 people have been interviewed. The prevalence of definite migraines was 40%, significantly higher among women and less educated people. About half of all headache sufferers and a third of migraineurs do not consider their condition as a disease and are not cared by any doctor. Among people seeking self-medication in pharmacies for acute headache attacks, the rate of definite or probable migraine is high, and a large percentage of them is not correctly diagnosed and treated. The pharmacy can be a valuable observatory for the study of headaches, and the first important step to improve the quality of care delivered to these patients

    Narrative Medicine to integrate patients’, caregivers’ and clinicians’ migraine experiences: the DRONE multicentre project

    Get PDF
    Background: Although migraine is widespread and disabling, stigmatisation and poor awareness of the condition still represent barriers to effective care; furthermore, research on migraine individual and social impact must be enhanced to unveil neglected issues, such as caregiving burden. The project investigated the migraine illness experience through Narrative Medicine (NM) to understand daily life, needs and personal resources of migraneurs, their caregivers and clinicians, and to provide insights for clinical practice. Methods: The project involved 13 Italian headache centres and targeted migraneurs, their caregivers and migraine specialists at these centres. Written narratives, composed by a sociodemographic survey and illness plot or parallel chart, were collected through the project’s webpage. Illness plots and parallel charts employed open words to encourage participants’ expression. Narratives were analysed through Nvivo software, interpretive coding and NM classifications. Results: One hundred and seven narratives were collected from patients and 26 from caregivers, as well as 45 parallel charts from clinicians. The analysis revealed migraine perception in social, domestic and work life within the care pathway evolution and a bond between chaos narratives and day loss due to migraine; furthermore, narratives suggested the extent of the caregiving burden and a risk of underestimation of migraine burden in patients’ and caregivers’ life. Conclusion: The project represents the first investigation on migraine illness experience through NM simultaneously considering migraneurs’, caregivers’ and clinicians’ perspectives. Comparing narratives and parallel charts allowed to obtain suggestions for clinical practice, while NM emerged as able to foster the pursuing of migraine knowledge and awareness

    On higher derivative gravity, c-theorems and cosmology

    Full text link
    We consider higher derivative gravity lagrangians in 3 and 4 dimensions, which admit simple c-theorems, including upto six derivative curvature invariants. Following a suggestion by Myers, these lagrangians are restricted such that the fluctuations around (anti) de Sitter spaces have second order linearized equations of motion. We study c-theorems both in the context of AdS/CFT and cosmology. In the context of cosmology, the monotonic function is the entropy defined on the apparent horizon through Wald's formula. Exact black hole solutions which are asymptotically (anti) de Sitter are presented. An interesting lower bound for entropy is found in de Sitter space. Some aspects of cosmology in both D=3 and D=4 are discussed.Comment: 23 pages, v3: clarifications added, references adde

    Joint Metabonomic and Instrumental Analysis for the Classification of Migraine Patients with 677-MTHFR Mutations

    Get PDF
    Migraine is a neurological disorder that correlates with an increased risk of cerebrovascular lesions. Genetic mutations of the MTHFR gene are correlated to migraine and to the increased risk of artery pathologies. Also, migraine patients show altered hematochemical parameters, linked to an impaired platelet aggregation mechanism. Hence, the vascular assessment of migraineurs is of primary importance

    Determinant and Weyl anomaly of Dirac operator: a holographic derivation

    Get PDF
    We present a holographic formula relating functional determinants: the fermion determinant in the one-loop effective action of bulk spinors in an asymptotically locally AdS background, and the determinant of the two-point function of the dual operator at the conformal boundary. The formula originates from AdS/CFT heuristics that map a quantum contribution in the bulk partition function to a subleading large-N contribution in the boundary partition function. We use this holographic picture to address questions in spectral theory and conformal geometry. As an instance, we compute the type-A Weyl anomaly and the determinant of the iterated Dirac operator on round spheres, express the latter in terms of Barnes' multiple gamma function and gain insight into a conjecture by B\"ar and Schopka.Comment: 11 pages; new comments and references added, typos correcte

    The effect of cigarette smoke exposure on the development of inflammation in lungs, gut and joints of TNFΔARE mice

    Get PDF
    The inflammatory cytokine TNF-alpha is a central mediator in many immune-mediated diseases, such as Crohn's disease (CD), spondyloarthritis (SpA) and chronic obstructive pulmonary disease (COPD). Epidemiologic studies have shown that cigarette smoking (CS) is a prominent common risk factor in these TNF-dependent diseases. We exposed TNF Delta ARE mice; in which a systemic TNF-alpha overexpression leads to the development of inflammation; to 2 or 4 weeks of air or CS. We investigated the effect of deregulated TNF expression on CS-induced pulmonary inflammation and the effect of CS exposure on the initiation and progression of gut and joint inflammation. Upon 2 weeks of CS exposure, inflammation in lungs of TNF Delta ARE mice was significantly aggravated. However, upon 4 weeks of CS-exposure, this aggravation was no longer observed. TNF Delta ARE mice have no increases in CD4+ and CD8+ T cells and a diminished neutrophil response in the lungs after 4 weeks of CS exposure. In the gut and joints of TNF Delta ARE mice, 2 or 4 weeks of CS exposure did not modulate the development of inflammation. In conclusion, CS exposure does not modulate gut and joint inflammation in TNF Delta ARE mice. The lung responses towards CS in TNF Delta ARE mice however depend on the duration of CS exposure

    Entanglement Entropy from a Holographic Viewpoint

    Get PDF
    The entanglement entropy has been historically studied by many authors in order to obtain quantum mechanical interpretations of the gravitational entropy. The discovery of AdS/CFT correspondence leads to the idea of holographic entanglement entropy, which is a clear solution to this important problem in gravity. In this article, we would like to give a quick survey of recent progresses on the holographic entanglement entropy. We focus on its gravitational aspects, so that it is comprehensible to those who are familiar with general relativity and basics of quantum field theory.Comment: Latex, 30 pages, invited review for Classical and Quantum Gravity, minor correction

    Thermal quenches in N=2* plasmas

    Full text link
    We exploit gauge/gravity duality to study `thermal quenches' in a plasma of the strongly coupled N=2* gauge theory. Specifically, we consider the response of an initial thermal equilibrium state of the theory under variations of the bosonic or fermionic mass, to leading order in m/T<<1. When the masses are made to vary in time, novel new counterterms must be introduced to renormalize the boundary theory. We consider transitions the conformal super-Yang-Mills theory to the mass deformed gauge theory and also the reverse transitions. By construction, these transitions are controlled by a characteristic time scale \calt and we show how the response of the system depends on the ratio of this time scale to the thermal time scale 1/T. The response shows interesting scaling behaviour both in the limit of fast quenches with T\calt<<1 and slow quenches with T\calt>>1. In the limit that T\calt\to\infty, we observe the expected adiabatic response. For fast quenches, the relaxation to the final equilibrium is controlled by the lowest quasinormal mode of the bulk scalar dual to the quenched operator. For slow quenches, the system relaxes with a (nearly) adiabatic response that is governed entirely by the late time profile of the mass. We describe new renormalization scheme ambiguities in defining gauge invariant observables for the theory with time dependant couplings.Comment: 78 pages, 17 figure

    Holographic c-theorems in arbitrary dimensions

    Full text link
    We re-examine holographic versions of the c-theorem and entanglement entropy in the context of higher curvature gravity and the AdS/CFT correspondence. We select the gravity theories by tuning the gravitational couplings to eliminate non-unitary operators in the boundary theory and demonstrate that all of these theories obey a holographic c-theorem. In cases where the dual CFT is even-dimensional, we show that the quantity that flows is the central charge associated with the A-type trace anomaly. Here, unlike in conventional holographic constructions with Einstein gravity, we are able to distinguish this quantity from other central charges or the leading coefficient in the entropy density of a thermal bath. In general, we are also able to identify this quantity with the coefficient of a universal contribution to the entanglement entropy in a particular construction. Our results suggest that these coefficients appearing in entanglement entropy play the role of central charges in odd-dimensional CFT's. We conjecture a new c-theorem on the space of odd-dimensional field theories, which extends Cardy's proposal for even dimensions. Beyond holography, we were able to show that for any even-dimensional CFT, the universal coefficient appearing the entanglement entropy which we calculate is precisely the A-type central charge.Comment: 62 pages, 4 figures, few typo's correcte
    corecore