2,479 research outputs found

    Thermodynamics of a class of non-asymptotically flat black holes in Einstein-Maxwell-Dilaton theory

    Full text link
    We analyse in detail the thermodynamics in the canonical and grand canonical ensembles of a class of non-asymptotically flat black holes of the Einstein-(anti) Maxwell-(anti) Dilaton theory in 4D with spherical symmetry. We present the first law of thermodynamics, the thermodynamic analysis of the system through the geometrothermodynamics methods, Weinhold, Ruppeiner, Liu-Lu-Luo-Shao and the most common, that made by the specific heat. The geometric methods show a curvature scalar identically zero, which is incompatible with the results of the analysis made by the non null specific heat, which shows that the system is thermodynamically interacting, does not possess extreme case nor phase transition. We also analyse the local and global stability of the thermodynamic system, and obtain a local and global stability for the normal case for 0<\gamma<1 and for other values of \gamma, an unstable system. The solution where \gamma=0 separates the class of locally and globally stable solutions from the unstable ones.Comment: 18 pages, version accepted for publication in General Relativity and Gravitatio

    Migraine aura: retracting particle-like waves in weakly susceptible cortex

    Get PDF
    Cortical spreading depression (SD) has been suggested to underlie migraine aura. Despite a precise match in speed, the spatio-temporal patterns of SD and aura symptoms on the cortical surface ordinarily differ in aspects of size and shape. We show that this mismatch is reconciled by utilizing that both pattern types bifurcate from an instability point of generic reaction-diffusion models. To classify these spatio-temporal pattern we suggest a susceptibility scale having the value [sigma]=1 at the instability point. We predict that human cortex is only weakly susceptible to SD ([sigma]&#x3c;1), and support this prediction by directly matching visual aura symptoms with anatomical landmarks using fMRI retinotopic mapping. We discuss the increased dynamical repertoire of cortical tissue close to [sigma]=1, in particular, the resulting implications on migraine pharmacology that is hitherto tested in the regime ([sigma]&#x3e;&#x3e;1), and potentially silent aura occurring below a second bifurcation point at [sigma]=0 on the susceptible scale

    Adaptation and validation of the Inventory of family protective factors for the portuguese culture

    Get PDF
    Aim: Describe the process of cultural adaptation and validation of Inventory of Family Protective Factors (IFPF) for portuguese culture. This instrument assesses the protective factors that contribute to family resilience. Studies of resilience fall the salutogenic paradigm, which focuses on protective factors of individuals or groups, without minimizing the risk factors and vulnerability. Methods: We applied this instrument to 85 families of children with special needs and, after linguistic and conceptual equivalence, used an exploratory factor analysis with principal components analysis (with varimax rotation) and calculated the Cronbach's alpha coefficient for each dimension. Results: adequate psychometric properties to be used in Portuguese population (Cronbach´s alpha =.90). Conclusion: IFPF is an useful instrument for studies which propose assess the protective factors of family resilience, however we suggest further studies of revalidation.Objetivo: Describir el proceso de adaptación cultural y validación para la cultura portuguesa de Inventory of Family Protective Factors (IFPF). Este instrumento evalúa los factores de protección que contribuyan a la resiliencia familiar. Estudios de resiliência familiar se apoyan en el paradigma salutogénico, que se centra en los factores de protección de individuos o grupos, sin subestimar los factores de riesgo y vulnerabilidad. Metodologia: Aplicamos este instrumento a 85 familias de niños con necesidades especiales y, después de la equivalencia lingüística y conceptual, hemos llevado a cabo un análisis factorial exploratorio de componentes principales con rotación varimax y calculamos el coeficiente alfa de Cronbach. Resultados: la IFPF tiene adecuadas propiedades psicométricas para la población portuguesa (alfa de Cronbach = .90). Conclusion: Esta es una herramienta útil para evaluar los factores protectores de la resiliencia familiar, sin embargo sugerimos estudios futuros de revalidación.Objetivos: adaptar e validar o Inventory of Family Protective Factors (IFPF) para a cultura portuguesa. Este instrumento avalia os fatores protetores que contribuem para a resiliência familiar. Os estudos sobre resiliência inserem-se no paradigma salutogénico, abordando os fatores protetores dos indivíduos ou grupos, sem subestimar os fatores de risco ou vulnerabilidade. Método: para avaliar a equivalência linguística e conceitual do IFPF realizamos a tradução, retroversão e reflexão falada; para aferir as características psicométricas do instrumento verificamos a sensibilidade, confiabilidade e a validade dos resultados. Realizamos uma análise fatorial de componentes principais com rotação varimax dos itens da escala e calculamos o coeficiente Alpha de Cronbach para cada dimensão. Através de uma amostragem aleatória simples, aplicamos este instrumento a 85 famílias de crianças com necessidades especiais que o auto-preencheram. Resultados: o IFPF apresenta características psicométricas adequadas para a população portuguesa (alfa de Cronbach de .90). Conclusão: o IFPF foi adaptado e validado para a cultura portuguesa. Consideramos tratar-se de um instrumento útil para estudos que se proponham avaliar os fatores protetores da resiliência familiar

    Impact of milk protein type on the viability and storage stability of microencapsulated Lactobacillus acidophilus using spray drying

    Get PDF
    Three different milk proteins — skim milk powder (SMP), sodium caseinate (SC) and whey protein concentrate (WPC) — were tested for their ability to stabilize microencapsulated L. acidophilus produced using spray drying. Maltodextrin (MD) was used as the primary wall material in all samples, milk protein as the secondary wall material (7:3 MD/milk protein ratio) and the simple sugars, d-glucose and trehalose were used as tertiary wall materials (8:2:2 MD/protein/sugar ratio) combinations of all wall materials were tested for their ability to enhance the microbial and techno-functional stability of microencapsulated powders. Of the optional secondary wall materials, WPC improved L. acidophilus viability, up to 70 % during drying; SMP enhanced stability by up to 59 % and SC up to 6 %. Lactose and whey protein content enhanced thermoprotection; this is possibly due to their ability to depress the glass transition and melting temperatures and to release antioxidants. The resultant L. acidophilus powders were stored for 90 days at 4 °C, 25 °C and 35 °C and the loss of viability calculated. The highest survival rates were obtained at 4 °C, inactivation rates for storage were dependent on the carrier wall material and the SMP/d-glucose powders had the lowest inactivation rates (0.013 day−1) whilst the highest was observed for the control containing only MD (0.041 day−1) and the SC-based system (0.030 day−1). Further increase in storage temperature (25 °C and 35 °C) was accompanied by increase of the inactivation rates of L. acidophilus that followed Arrhenius kinetics. In general, SMP-based formulations exhibited the highest temperature dependency whilst WPC the lowest. d-Glucose addition improved the storage stability of the probiotic powders although it was accompanied by an increase of the residual moisture, water activity and hygroscopicity, and a reduction of the glass transition temperature in the tested systems

    Performance of the CMS Cathode Strip Chambers with Cosmic Rays

    Get PDF
    The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

    Search for direct pair production of the top squark in all-hadronic final states in proton-proton collisions at s√=8 TeV with the ATLAS detector

    Get PDF
    The results of a search for direct pair production of the scalar partner to the top quark using an integrated luminosity of 20.1fb−1 of proton–proton collision data at √s = 8 TeV recorded with the ATLAS detector at the LHC are reported. The top squark is assumed to decay via t˜→tχ˜01 or t˜→ bχ˜±1 →bW(∗)χ˜01 , where χ˜01 (χ˜±1 ) denotes the lightest neutralino (chargino) in supersymmetric models. The search targets a fully-hadronic final state in events with four or more jets and large missing transverse momentum. No significant excess over the Standard Model background prediction is observed, and exclusion limits are reported in terms of the top squark and neutralino masses and as a function of the branching fraction of t˜ → tχ˜01 . For a branching fraction of 100%, top squark masses in the range 270–645 GeV are excluded for χ˜01 masses below 30 GeV. For a branching fraction of 50% to either t˜ → tχ˜01 or t˜ → bχ˜±1 , and assuming the χ˜±1 mass to be twice the χ˜01 mass, top squark masses in the range 250–550 GeV are excluded for χ˜01 masses below 60 GeV

    Fit to Race: Identifying the balance, type and sources of knowledge in fitness for Motorsport

    Get PDF
    In Motorsport, due perhaps to a lack of empirical evidence, it is not always clear what fitness training is required and what roles specific fitness components play, particularly outside the elite levels. Consequently, drivers and their trainers are often left to their own devices, placing reliance on anecdotal information. Accordingly, using a large sample of racing drivers, coaches and fitness trainers, the aim of this investigation was to identify the perceived importance and contribution of fitness components, the sources of information used to reach these conclusions and levels of confidence in the views reported. Survey data from 166 drivers (151 males, 15 females) showed that, in general, cardiovascular fitness, upper body strength, coordination and reactions were perceived as being the most important. Data on sources of information used supported the conjecture that training can often be based on “word of mouth”. Despite a fairly high level of confidence in the views expressed, there is clearly a significant opportunity for practitioners working within Motorsport to provide clearer, proven information so that drivers can feel confident that they are training optimally

    Drug repurposing for identification of new efflux inhibitors and/or antibiofilm agents against Staphylococcus aureus and Staphylococcus epidermidis

    Get PDF
    Background Staphylococcus aureus (SA) and Staphylococcus epidermidis (SE) are frequent pathogens causing nosocomial infections. Efflux-mediated resistance and biofilm formation may contribute to the emergence of resistance in these species and resilience of such infections to chemotherapeutics. In this work, we applied an in silico drug repurposing strategy to identify drugs that can target efflux and/or biofilm formation, to be then assessed in vitro for their efflux inhibitory and/or antibiofilm activities. Methods A list of targets, corresponding to all SA and SE membrane transporters and biofilmassociated proteins was used to interrogate the DrugBank database and generate a list of approved drugs targeting these proteins or their homologues. Representative candidate drugs were chosen for validation in an experimental model based on reference and isogenic strains differing in norA expression (gene encoding the main staphylococcal efflux pump NorA). To assess efflux inhibitory activity, the drugs MICs were determined by broth microdilution and each drug (at ¼ MIC) tested for its ability to reduce MICs of selected antimicrobials (NorA substrates and non-substrates). Drugs with significant effect (≥ four-fold MIC reduction) were further tested for synergism with those antimicrobials by checkerboard assays and their potential to inhibit biofilm formation by the crystal violet adhesion method. Results We identified over 200 drugs that potentially target SA and/or SE membrane transporters or biofilm-associated proteins. Seven of these candidate drugs were tested: desipramine, chloroquine, atovaquone, topiramate, amlodipine, tariquidar and sulpiride. All drugs showed high MICs (>64 mg/L) against all staphylococcal strains. Tariquidar, amlodipine, desipramine and chloroquine reduced the MICs of NorA substrates in norA-overexpressing SA and SE strains, suggesting they possess efflux inhibitory activity. Moreover, amlodipine and tariquidar presented significant synergism with some NorA substrates. Amlodipine was the only drug able to abolish biofilm formation in SA, whereas desipramine and chloroquine were more effective against SE biofilms. Conclusions This work reveals amlodipine, desipramine and chloroquine as new potential dual target drugs and tariquidar as a potent efflux inhibitor in staphylococci. These drugs may, in the future, be included in the fight against antimicrobial-resistant S. aureus and S. epidermidis infections. J. Neves and C. Antunes contributed equally to this work. Acknowledgement of grants and fundings, word count: 30 words Project DREBI, Ref. 2022.07931.PTDC funded by Fundação para a Ciência e a Tecnologia (FCT, Portugal) and Project BIOSAFE funded by FEDER through the Programa Operacional Factores de Competitividade - COMPETE and FCT (Portugal), Grant LISBOA-01-0145-FEDER-030713, PTDC/CAL-EST/30713/2017. Further support by FCT to GHTM (UID/04413/2020).publishe

    The role of glycans in health and disease: Regulators of the interaction between gut microbiota and host immune system

    Get PDF
    The human gut microbiota is home to a diverse collection of microorganisms that has co-evolved with the host immune system in which host-microbiota interactions are essential to preserve health and homeostasis. Evidence suggests that the perturbation of this symbiotic host-microbiome relationship contributes to the onset of major diseases such as chronic inflammatory diseases including Inflammatory Bowel Disease. The host glycocalyx (repertoire of glycans/sugar-chains at the surface of gut mucosa) constitutes a major biological and physical interface between the intestinal mucosa and microorganisms, as well as with the host immune system. Glycans are an essential niche for microbiota colonization and thus an important modulator of host-microorganism interactions both in homeostasis and in disease. In this review, we discuss the role of gut mucosa glycome as an instrumental pathway that regulates host-microbiome interactions in homeostasis but also in health to inflammation transition. We also discuss the power of mucosa glycosylation remodelling as an attractive preventive and therapeutic strategy to preserve gut homeostasis.Co-funded by the European Union (GlycanTrigger, Grant Agreement No: 101093997). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council Executive Agency. Neither the European Union nor the granting authority can be held responsible for them. Salomé S. Pinho acknowledges funding from European Crohn’s and Colitis Organisation (ECCO) Pioneer Award 2021. Salomé S. Pinho also acknowledges the International Organization for the study of Inflammatory Bowel Disease (IOIBD) and the Portuguese Foundation for Science and Technology (FCT; EXPL/MED-ONC/0496/2021). Cláudia Rodrigues thanks FCT for funding (2020.08422.BD). Joana Gaifem acknowledges funding from European Crohn’s and Colitis Organisation (ECCO Grant) and FCT (DOI 10.54499/2020.00088.CEECIND/CP1608/ CT0001). The Crouch Lab is funded by The Academy of Medical Sciences (SBF0061175) and the Wellcome Trust/Royal Society Henry Dale Fellowship (224240/Z/21/Z)
    corecore