535 research outputs found

    Thermodynamics, phase transitions and Ruppeiner geometry for Einstein-dilaton Lifshitz black holes in the presence of Maxwell and Born-Infeld electrodynamics

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    In this paper, we first obtain the (n+1n+1)-dimensional dilaton-Lifshitz black hole (BH) solutions in the presence of Born-Infeld (BI) electrodynamics. We find that there are two different solutions for z=n+1z=n+1 and zn+1z\neq n+1 cases (zz is dynamical critical exponent). We show that the thermodynamics first law is satisfied for both cases. Then, we turn to study different phase transitions (PTs) for our BHs. We start with study of Hawking-Page PT for both linearly and BI charged BHs. After that, we discuss the PTs inside the BHs. We present the improved Davies quantities and prove that the PT points shown by them coincide with Ruppeiner ones. We show that the zero temperature PTs are transitions on radiance properties of BHs by using Landau-Lifshitz theory. Next, we turn to study Ruppeiner geometry of linearly and BI charged BHs. For linearly charged case, we show that there are no PT at finite temperature for the case z2z\geq 2. For z<2z<2, it is found that the number of finite temperature PT points depends on the value of BH charge and is not more than two. When we have two finite temperature PT points, there are no thermally stable BH between these two points and we have discontinues small/large BH PTs. As expected, for small BHs, we observe finite magnitude for Ruppeiner invariant which shows the finite correlation between possible BH molecules while for large BHs, the correlation is very small. Finally, we study the Ruppeiner geometry and thermal stability of BI charged Lifshtiz BHs for different values of zz. We observe that small BHs are thermally unstable in some situations. Also, the behavior of correlation between possible BH molecules for large BHs is the same as linearly charged case. In both linearly and BI charged cases, for some choices of parameters, the BH systems behave like a Van der Waals gas near transition point.Comment: V2: 23 pages (revtex format), 13 figures (except one, all include subfigures), some references adde

    Protozoans; (Coccidia and Myxosporea;) infections in some fishes of Aras and Mahabad Dams (Northwest of Iran)

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    During a protozoological study on the fishes of West-Azarbayejan province (Northwest of Iran) in 1998, three different protozoans were revealed. Myxobolus musayevi from Capoeta capoeta, Myxobolus dispar from Aspius aspius taeniatus and Goussia carpelli from Cyprinus carpio. Altogether 13 different fish specimen were examined. The fishes including: Aspius aspius taeniatus (2), Rutilus ruti/us (3), Capoeta cpoeta (2) and Cyprinus carpio (6). They were caugth from Aras and Mahabad Dams and transported alive to the laboratory where they were wieghted and measured. Then, they were examined for protozoan infections when their spinal cord was cut. Myxobolus musayevi had already reported from Capoeta capoeta from Taj an in Mazandaran province. This is the first record of Myxobolus dispar from Aspius aspius taeniatus from Iranian freshwaters. Goussia carpelli also had already recorded (unpublished) from the Cyprinus carpio from Sepeedroud River in Guilan province. In this study, three of C. carpio which were caught from Aras Dam had been infected by the oocyst of the Goussia carpelli in the mocus of the intestine

    Black Holes in (Quartic) Quasitopological Gravity

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    We construct quartic quasitopological gravity, a theory of gravity containing terms quartic in the curvature that yields second order differential equations in the spherically symmetric case. Up to a term proportional to the quartic term in Lovelock gravity we find a unique solution for this quartic case, valid in any dimensionality larger than 4 except 8. This case is the highest degree of curvature coupling for which explicit black hole solutions can be constructed, and we obtain and analyze the various black hole solutions that emerge from the field equations in (n+1)(n+1) dimensions. We discuss the thermodynamics of these black holes and compute their entropy as a function of the horizon radius. We then make some general remarks about KK-th order quasitopological gravity, and point out that the basic structure of the solutions will be the same in any dimensionality for general KK apart from particular cases.Comment: LaTex, 9 figures, 27 pages. A new section on holographic hydrodynamics is added. Introduction and concluding remarks have been revise

    Roles of estrogen receptor-alpha in mediating life span: the hypothalamic deregulation hypothesis.

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    In several species caloric restriction (CR) extends life span. In this paper we integrate data from studies on CR and other sources to articulate the hypothalamic deregulation hypothesis by which estrogen receptor-alpha (ER-α) signaling in the hypothalamus and limbic system affects life span under the stress of CR in mammals. ER-α is one of two principal estrogen-binding receptors differentially expressed in the amygdala, hippocampus, and several key hypothalamic nuclei: the arcuate nucleus (ARN), preoptic area (POA), ventromedial nucleus (VMN), antero ventral periventricular nucleus (AVPV), paraventricular nucleus (PVN), supraoptic nucleus (SON), and suprachiasmatic nucleus (SCN). Estradiol signaling via ER-α is essential in basal level functioning of reproductive cycle, sexually receptive behaviors, physiological stress responses, as well as sleep cycle, and other nonsexual behaviors. When an organism is placed under long-term CR, which introduces an external stress to this ER-α signaling, the reduction of ER-α expression is attenuated over time in the hypothalamus. This review paper seeks to characterize the downstream effects of ER-α in the hypothalamus and limbic system that affect normal endocrine functioning

    Foodborne Listeriosis

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    Abstract: Foodborne listeriosis is a rare and very dangerous disease which is caused by Listeria monocytogenes. This bacterium is found in the nature in very high population, but can cause disease only in certain groups of people. Listeriosis usually happens after consumption of unpasteurized dairy products especially soft and unripe cheeses and ready to eat meat products like hot dog by susceptible people. In general, pregnant women, infants, elderly people and immuno deficient patients are susceptible to this disease. Listeria monocytogenes is able to produce septicemia, meningitis and abortion in human. The important characteristic of this bacterium is its ability to live inside the cells of immune system and by this way, it is able to distribute through body easily. In order to prevent listeriosis, susceptible people should avoid eating unpasteurized dairy products and ready to eat meats. Keywords: Foodborne disease, Listeria infections, Listeria monocytogene

    Realist evaluation of UK medical education quality assurance

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    OBJECTIVES: The aim of the study was to explore what components of the General Medical Council’s (GMC) Quality Assurance Framework work, for whom, in what circumstances and how? SETTING: UK undergraduate and postgraduate medical education and training. PARTICIPANTS: We conducted interviews with a stratified sample of 36 individuals. This included those who had direct experiences, as well as those with external insights, representing local, national and international organisations within and outside medicine. INTERVENTION: The GMC quality assure education to protect patient and public safety utilising complex intervention components including meeting standards, institutional visits and monitoring performance. However, the context in which these are implemented matters. We undertook an innovative realist evaluation to test an initial programme theory. Data were analysed using framework analysis. RESULTS: Across components of the intervention, we identified key mechanisms, including transparent reporting to promote quality improvement; dialogical feedback; partnership working facilitating interactions between regulators and providers, and role clarity in conducting proportionate interventions appropriate to risk. The GMC’s framework was commended for being comprehensive and enabling a broad understanding of an organisation’s performance. Unintended consequences included confusion over roles and boundaries in different contexts which often undermined effectiveness. CONCLUSIONS: his realist evaluation substantiates the literature and reveals deeper understandings about quality assuring medical education. While standardised approaches are implemented, interventions need to be contextually proportionate. Routine communication is beneficial to verify data, share concerns and check risk; however, ongoing partnership working can foster assurance. The study provides a modified programme theory to explicate how education providers and regulators can work more effectively together to uphold education quality, and ultimately protect public safety. The findings have influenced the GMC’s approach to quality assurance which impacts on all medical students and doctors in training

    Neuroprotective Effects of Bone Marrow Mesenchymal Stem Cells on Bilateral Common Carotid Arteries Occlusion Model of Cerebral Ischemia in Rat

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    Cell therapy is the most advanced treatment of the cerebral ischemia, nowadays. Herein, we discuss the neuroprotective effects of bone marrow mesenchymal stem cells (BMSCs) on rat hippocampal cells following intravenous injection of these cells in an ischemia-reperfusion model. Adult male Wistar rats were divided into 5 groups: control, sham (surgery without blockage of common carotid arteries), ischemia (common carotid arteries were blocked for 30 min prior to reperfusion), vehicle (7 days after ischemia PBS was injected via the tail vein), and treatment (injections of BMSC into the tail veins 7 days after ischemia). We performed neuromuscular and vestibulomotor function tests to assess behavioral function and, finally, brains were subjected to hematoxylin and eosin (H&E), anti-Brdu immunohistochemistry, and TUNEL staining. The ischemia group had severe apoptosis. The group treated with BMSCs had a lower mortality rate and also had significant improvement in functional recovery (P<0.001). Ischemia-reperfusion for 30 min causes damage and extensive neuronal death in the hippocampus, especially in CA1 and CA3 regions, leading to several functional and neurological deficits. In conclusion, intravenous injection of BMSCs can significantly decrease the number of apoptotic neurons and significantly improve functional recovery, which may be a beneficial treatment method for ischemic injuries. © 2016 Bagher Pourheydar et al

    Causes of Death Accompanying by Soft Tissue Neck Hemorrhage

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    Background: Generally, soft tissue hemorrhages in anterior part of the neck are attributed to the neck compression or trauma and suspicion goes more to homicidal death than suicide. Although artificial posterior neck hemorrhages are described as Prinsloo-Gordon phenomenon in cadavers with posterior lividity, studies conducted on such hemorrhages in the anterior and lateral compartments are rare. This study intends to investigate causes of death accompanied by soft tissue neck hemorrhages in different compartments of neck. Method: In this retrospective case series, between March 2008 and 2009, cadavers whose autopsies indicated soft tissue neck hemorrhages and the lividity was dominant in posterior, were evaluated according to the cause of death and anatomical and histological locations of hemorrhage. Results: Among 86 cases of neck hemorrhage, 72.1% (n=62) were male. Direct neck trauma, hanging, strangulation, chocking and positional asphyxia constituted 50% (n=43) of them, 40.7% (n=35) were non-asphyxial, non-traumatic deaths such as natural diseases, drug and CO poisoning, electrocution and drowning, and 9.3% (n=8) were unknown. 65.1% (n=28) of non-traumatic, non-asphyxial cases bore anterior or lateral neck hemorrhages. Conclusion: The considerable prevalence of soft neck tissue hemorrhages in non asphyxial deaths with no history of neck trauma and the location of such hemorrhages in anterior and lateral sides of neck, lead the investigators to pay more attention to interpret these hemorrhages and determining the mode and cause of death

    The GP Tests of Competence assessment: which part best predicts fitness to practise decisions?

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    BACKGROUND: The General Medical Council (GMC) conducts Tests of Competence (ToC) for doctors referred for Fitness to Practise (FtP) issues. GPs take a single best answer knowledge test, an Objective Structured Clinical Examination (OSCE), and a Simulated Surgery (SimSurg) assessment which is a simulated GP consultation. The aim of this study was to examine the similarities between OSCEs and SimSurg to determine whether each assessment contributed something unique to GP ToCs. METHODS: A mixed methods approach was used. Data were collated on 153 GPs who were required to undertake a ToC as a part of being investigated for FtP issues between February 2010 and October 2016. Using correlation analysis, we examined to what degree performance on the knowledge test, OSCE, and SimSurg related to case examiner recommendations and FtP outcomes, including the unique predictive power of these three assessments. The outcome measures were case examiner recommendations (i) not fit to practise; ii) fit to practise on a limited basis; or iii) fit to practise) as well as FtP outcomes (i) erased/removed from the register; ii) having restrictions/conditions; or iii) be in good standing). For the qualitative component, 45 GP assessors were asked to rate whether they assess the same competencies and which assessment provides better feedback about candidates. RESULTS: There was significant overlap between OSCEs and SimSurg, p < 0.001. SimSurg had additional predictive power in the presence of OSCEs and the knowledge test (p = 0.030) in distinguishing doctors from different FtP categories, while OSCEs did not (p = 0.080). Both the OSCEs (p = 0.004) and SimSurg (p < 0.001) had significant negative correlations with case examiner recommendations when accounting for the effects of the other two assessments. Inductive thematic analysis of the responses to the questionnaire showed that assessors perceived OSCEs to be better suited to target specific knowledge and skills. SimSurg was thought to produce a more global picture as the scenarios more accurately portray a patient consultation. CONCLUSION: While all three assessments are strong predictors of both case examiner recommendations and FtP outcomes, our findings suggest that the efficiency of GP ToCs can be improved by removing some of this overlapping content
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