Semiclassical Quantization of the Superstring and Hagedorn Temperature

In a recent paper [1], the semiclassical quantization of a string, winding once around the compact Euclidean time circle, on a supergravity background dual to the deep infrared regime of a confining finite temperature gauge theory, was carried out. The string mass-shell condition and, by extrapolation, the Hagedorn temperature to leading order in the holographic limit was deduced. In this work, we improve on those results in three ways. First, we fix some missing details of the related light-cone quantization analysis. Second, we reconsider the problem under the lens of a background-covariant geometrical formalism. This allows us to put the semiclassical mass-shell condition on more solid grounds. Finally, going beyond the semiclassical regime, we compute the Hagedorn temperature at next-to-leading order in the holographic limit. The sub-leading correction turns out to arise entirely from the contribution of the zero modes of the massive worldsheet scalar fields. Our result matches that of a recent analysis in the literature based on the Horowitz-Polchinski stringy star effective model.Comment: 43 page

Chapter Boccaccio, il Decameron e la Crusca: le fonti spogliate dagli Accademici

This survey concerns the lexicographic presence of Giovanni Boccaccio’s Decameron in the Vocabolario of the Accademici della Crusca (from the first to the fourth edition). Boccaccio is the author that counts 15.600 occurrences (considering also his others literary works) already in the first edition. This is a significant situation about Decameron, because we know that a lot of its passages went through modifications and censorship: all of these interventions on Boccaccio’s text would have had some influence on the quotations into the Vocabolario. Starting from the declarations of the Accademici, the study wants to investigate about the employment of Decameron’s sources during the works for the Vocabolario, involving editions, manuscripts and Accademici’s autograph papers

Higher Order Corrections to the Hagedorn Temperature at Strong Coupling

We propose a general formula for higher order corrections to the value of the Hagedorn temperature of a class of holographic confining gauge theories in the strong coupling expansion. Inspired by recent proposals in the literature, the formula combines the sigma-model string expansion with an effective approach. In particular, it includes the sigma-model contributions to the Hagedorn temperature at next-to-next-to leading order, which are computed in full generality. For ${\cal N}=4$ SYM on $S^3$ our result agrees with numerical field theory estimates with excellent precision. We use the general formula to predict the value of the Hagedorn temperature for ABJM on $S^2$ and for the dual of purely RR global $AdS_3$.Comment: 13 page

Vagus nerve stimulation in patients with migraine

ntroducción. La estimulación del nervio vago (ENV) está aprobada para el tratamiento de la epilepsia refractaria cuando no es posible cirugía resectiva, con una eficacia bien establecida. Series publicadas sugieren un efecto beneficioso de la ENV en la migraña. Objetivos. Determinar el grado de mejoría de la cefalea en pacientes migrañosos a los que se les había implantado una ENV para tratamiento de la epilepsia refractaria y evaluar qué variables se asocian a mayor posibilidad de éxito con esta medida. Pacientes y métodos. Estudio observacional y retrospectivo desde el 1 de enero de 1999 hasta el 31 de diciembre de 2010. Se contactó telefónicamente con los pacientes con ENV para epilepsia refractaria, seleccionando a aquéllos que cumplían los criterios de la Sociedad Internacional de Cefaleas para la migraña. Se recogieron edad, género, año de implantación, edad de inicio de la epilepsia y la migraña, mejoría de crisis y de migraña, presencia de aura migrañosa y coexistencia de síndrome ansiosodepresivo. Se contactó con 94 pacientes con ENV y se seleccionó a 13 pacientes migrañosos. Resultados. Tras la implantación de la ENV, se observó una disminución de al menos el 50% de los episodios de migraña en nueve pacientes (69%) (p = 0,004), así como una disminución del número de episodios de migraña en aquellos pacientes que también habían reducido sus crisis epilépticas (p = 0,012). No se observaron asociaciones estadísticamente significativas en cuanto al sexo, edad, tiempo de evolución, existencia de aura migrañosa o coexistencia de síndrome ansiosodepresivo. Conclusiones. La ENV podría resultar beneficiosa en pacientes con migraña, especialmente en casos de difícil control. Debido al tipo estudio, hay que tomar estas conclusiones con precaución. Serán necesarios estudios clínicos prospectivos antes de llevarse a la práctica clínica habitualIntroduction. Vagus nerve stimulation (VNS) has been approved for the treatment of refractory epilepsy when resective surgery is not possible, and has proved to be highly effective. Series published in the literature suggest a beneficial effect of VNS in the treatment of migraine. Aims. To determine the degree to which headaches improve in patients with migraine after the placement of VNS to treat refractory epilepsy, and to evaluate what variables are associated with an increased chance of success with this measure. Patients and methods. An observation-based retrospective study was conducted from 1st January 1999 until 31st December 2010. Patients with VNS for refractory epilepsy were contacted by telephone, after selecting those who fulfilled International Headache Society criteria for migraine. Data collected included age, gender, year of placement, age at onset of epilepsy and migraine, improvement of seizures and migraine, presence of migraine with aura and coexistence of anxious-depressive syndrome. Ninety-four patients with VNS were contacted and 13 patients with migraine were selected. Results. Following placement of the VNS, the number of episodes of migraine was seen to decrease by at least 50% in nine patients (69%) (p = 0.004) and there was a drop in the number of episodes of migraine in those patients who had also reduced their epileptic seizures (p = 0.012). No statistically significant associations were observed as regards sex, age, length of disease history, existence of migraine with aura or coexistence of anxious-depressive syndrome. Conclusions. VNS could have beneficial effects for patients with migraine, especially in cases that are difficult to control. Due to the type of study, these conclusions must be taken with caution. Prospective clinical studies are needed before introducing the technique into daily clinical practic

CLIPPERS syndrome with atypical distribution of lesions in magnetic resonance imaging of the brain

Introducción. El síndrome CLIPPERS (chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids) es un proceso inflamatorio del sistema nervioso central cuyo rasgo distintivo son las lesiones puntiformes en el troncoencéfalo captantes en los estudios de resonancia magnética. Clínicamente, cursa con disartria, ataxia y diplopía, y suele responder a corticoides. Anatomopatológicamente, aparecen infiltrados de linfocitos T en los espacios perivasculares troncoencefálicos. Caso clínico. Mujer de 40 años con cuadro de instauración subaguda de diplopía binocular, ataxia y disartria. En la resonancia magnética cerebral presentó lesiones puntiformes hipertintensas en secuencia T2 en el tronco, cerebelo, diencéfalo y áreas córtico-subcorticales bihemisféricas, que realzaron con contraste. Se realizó un estudio etiológico para descartar un origen infeccioso, neoplásico o inflamatorio subyacente, que resultó negativo. La paciente recibió tratamiento en dos ocasiones con metilprednisolona, con descenso progresivo de la dosis, con buena respuesta. Conclusiones. La diplopía y la ataxia, como en nuestro caso, están presentes prácticamente siempre. Los hallazgos en la RM consisten en lesiones captantes puntiformes localizadas en la protuberancia con extensión hacia el cerebelo, ganglios basales y cuerpo calloso, con gradiente de captación menor conforme se alejan rostralmente hacia la corteza, y caudalmente hacia la médula. En el caso de nuestra paciente, este gradiente no se respeta, encontrándose una densidad similar de las lesiones a nivel supratentorial. El diagnóstico diferencial es amplio y justifica un estudio diagnóstico extenso, y en casos seleccionados la biopsia cerebral. El curso de la enfermedad es remitente-recurrente, y el pronóstico mejora cuanto más precoz y prolongado es el tiempo de corticoterapiaIntroduction. CLIPPERS syndrome (chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids) is an inflammatory process of the central nervous system whose distinguishing features are the enhancing punctiform lesions in the brainstem that appear in the magnetic resonance images. Clinically, it is accompanied by dysarthria, ataxia and diplopia, and usually responds to treatment with corticoids. Pathologically, T lymphocytes appear infiltrated in the perivascular spaces of the brainstem. Case report. We report the case of a 40-year-old woman with an initial subacute clinical picture of binocular diplopia, ataxia and dysarthria. The magnetic resonance brain scan revealed T2 hyperintense punctiform lesions in the stem, cerebellum, diencephalons and cortico-subcortical areas of both hemispheres, which were enhanced with contrast. An aetiological study was performed to rule out any underlying infectious, neoplastic or inflammatory origin, the results being negative. The patient was treated on two occasions with methylprednisolone, with a gradual lowering of the dosage, the response being favourable. Conclusions. Diplopia and ataxia, as in our case, are practically always present. The MR findings consist of punctiform enhancing lesions located in the pons extending towards the cerebellum, basal ganglia and corpus callosum, the enhancement gradient becoming lower as the distance increases rostrally away from the cortex, and caudally towards the spinal cord. In the case of our patient, this gradient is not respected, and the density found was similar to that of lesions at the supratentorial level. The differential diagnosis is wide-ranging and justifies an extensive diagnostic study with, in certain cases, a biopsy study of brain tissue. The disease courses in a relapsing-remitting pattern and the earlier steroid therapy is established and the more prolonged it is, the better the prognosis will b

Spontaneous Subarachnoid Hemorrhage: A Systematic Review and Meta-analysis Describing the Diagnostic Accuracy of History, Physical Examination, Imaging, and Lumbar Puncture With an Exploration of Test Thresholds.

BACKGROUND: Spontaneous subarachnoid hemorrhage (SAH) is a rare, but serious etiology of headache. The diagnosis of SAH is especially challenging in alert, neurologically intact patients, as missed or delayed diagnosis can be catastrophic. OBJECTIVES: The objective was to perform a diagnostic accuracy systematic review and meta-analysis of history, physical examination, cerebrospinal fluid (CSF) tests, computed tomography (CT), and clinical decision rules for spontaneous SAH. A secondary objective was to delineate probability of disease thresholds for imaging and lumbar puncture (LP). METHODS: PubMed, Embase, Scopus, and research meeting abstracts were searched up to June 2015 for studies of emergency department patients with acute headache clinically concerning for spontaneous SAH. QUADAS-2 was used to assess study quality and, when appropriate, meta-analysis was conducted using random effects models. Outcomes were sensitivity, specificity, and positive (LR+) and negative (LR-) likelihood ratios. To identify test and treatment thresholds, we employed the Pauker-Kassirer method with Bernstein test indication curves using the summary estimates of diagnostic accuracy. RESULTS: A total of 5,022 publications were identified, of which 122 underwent full-text review; 22 studies were included (average SAH prevalence = 7.5%). Diagnostic studies differed in assessment of history and physical examination findings, CT technology, analytical techniques used to identify xanthochromia, and criterion standards for SAH. Study quality by QUADAS-2 was variable; however, most had a relatively low risk of biases. A history of neck pain (LR+ = 4.1; 95% confidence interval [CI] = 2.2 to 7.6) and neck stiffness on physical examination (LR+ = 6.6; 95% CI = 4.0 to 11.0) were the individual findings most strongly associated with SAH. Combinations of findings may rule out SAH, yet promising clinical decision rules await external validation. Noncontrast cranial CT within 6 hours of headache onset accurately ruled in (LR+ = 230; 95% CI = 6 to 8,700) and ruled out SAH (LR- = 0.01; 95% CI = 0 to 0.04); CT beyond 6 hours had a LR- of 0.07 (95% CI = 0.01 to 0.61). CSF analyses had lower diagnostic accuracy, whether using red blood cell (RBC) count or xanthochromia. At a threshold RBC count of 1,000 × 10(6) /L, the LR+ was 5.7 (95% CI = 1.4 to 23) and LR- was 0.21 (95% CI = 0.03 to 1.7). Using the pooled estimates of diagnostic accuracy and testing risks and benefits, we estimate that LP only benefits CT-negative patients when the pre-LP probability of SAH is on the order of 5%, which corresponds to a pre-CT probability greater than 20%. CONCLUSIONS: Less than one in 10 headache patients concerning for SAH are ultimately diagnosed with SAH in recent studies. While certain symptoms and signs increase or decrease the likelihood of SAH, no single characteristic is sufficient to rule in or rule out SAH. Within 6 hours of symptom onset, noncontrast cranial CT is highly accurate, while a negative CT beyond 6 hours substantially reduces the likelihood of SAH. LP appears to benefit relatively few patients within a narrow pretest probability range. With improvements in CT technology and an expanding body of evidence, test thresholds for LP may become more precise, obviating the need for a post-CT LP in more acute headache patients. Existing SAH clinical decision rules await external validation, but offer the potential to identify subsets most likely to benefit from post-CT LP, angiography, or no further testing

Buprenorphine for neuropathic pain in adults

BACKGROUND Opioid drugs, including buprenorphine, are commonly used to treat neuropathic pain, and are considered effective by some professionals. Most reviews have examined all opioids together. This review sought evidence specifically for buprenorphine, at any dose, and by any route of administration. Other opioids are considered in separate reviews. OBJECTIVES To assess the analgesic efficacy of buprenorphine for chronic neuropathic pain in adults, and the adverse events associated with its use in clinical trials. SEARCH METHODS We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and EMBASE from inception to 11 June 2015, together with reference lists of retrieved papers and reviews, and two online study registries. SELECTION CRITERIA We included randomised, double-blind studies of two weeks' duration or longer, comparing any oral dose or formulation of buprenorphine with placebo or another active treatment in chronic neuropathic pain. DATA COLLECTION AND ANALYSIS Two review authors independently searched for studies, extracted efficacy and adverse event data, and examined issues of study quality. We did not carry out any pooled analyses. MAIN RESULTS Searches identified 10 published studies, and one study with results in ClinicalTrials.gov. None of these 11 studies satisfied our inclusion criteria, and so we included no studies in the review. AUTHORS' CONCLUSIONS There was insufficient evidence to support or refute the suggestion that buprenorphine has any efficacy in any neuropathic pain condition

Fentanyl for neuropathic pain in adults

BACKGROUND Opioid drugs, including fentanyl, are commonly used to treat neuropathic pain, and are considered effective by some professionals. Most reviews have examined all opioids together. This review sought evidence specifically for fentanyl, at any dose, and by any route of administration. Other opioids are considered in separate reviews. OBJECTIVES To assess the analgesic efficacy of fentanyl for chronic neuropathic pain in adults, and the adverse events associated with its use in clinical trials. SEARCH METHODS We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and Embase from inception to June 2016, together with the reference lists of retrieved articles, and two online study registries. SELECTION CRITERIA We included randomised, double-blind studies of two weeks' duration or longer, comparing fentanyl (in any dose, administered by any route, and in any formulation) with placebo or another active treatment in chronic neuropathic pain. DATA COLLECTION AND ANALYSIS Two review authors independently searched for studies, extracted efficacy and adverse event data, and examined issues of study quality and potential bias. We did not carry out any pooled analyses. We assessed the quality of the evidence using GRADE. MAIN RESULTS Only one study met our inclusion criteria. Participants were men and women (mean age 67 years), with postherpetic neuralgia, complex regional pain syndrome, or chronic postoperative pain. They were experiencing inadequate relief from non-opioid analgesics, and had not previously taken opioids for their neuropathic pain. The study used an enriched enrolment randomised withdrawal design. It was adequately blinded, but we judged it at unclear risk of bias for other criteria.Transdermal fentanyl (one-day fentanyl patch) was titrated over 10 to 29 days to establish the maximum tolerated and effective dose (12.5 to 50 µg/h). Participants who achieved a prespecified good level of pain relief with a stable dose of fentanyl, without excessive use of rescue medication or intolerable adverse events ('responders'), were randomised to continue with fentanyl or switch to placebo for 12 weeks, under double-blind conditions. Our prespecified primary outcomes were not appropriate for this study design, but the measures reported do give an indication of the efficacy of fentanyl in this condition.In the titration phase, 1 in 3 participants withdrew because of adverse events or inadequate pain relief, and almost 90% experienced adverse events. Of 258 participants who underwent open-label titration, 163 were 'responders' and entered the randomised withdrawal phase. The number of participants completing the study (and therefore continuing on treatment) without an increase of pain by more than 15/100 was 47/84 (56%) with fentanyl and 28/79 (35%) with placebo. Because only 63% responded sufficiently to enter the randomised withdrawal phase, this implies that only a maximum of 35% of participants entering the study would have had useful pain relief and tolerability with transdermal fentanyl, compared with 22% with placebo. Almost 60% of participants taking fentanyl were 'satisfied' and 'very satisfied' with their treatment at the end of the study, compared with about 40% with placebo. This outcome approximates to our primary outcome of moderate benefit using the Patient Global Impression of Change scale, but the group was enriched for responders and the method of analysis was not clear. The most common adverse events were constipation, nausea, somnolence, and dizziness.There was no information about other types of neuropathic pain, other routes of administration, or comparisons with other treatments.We downgraded the quality of the evidence to very low because there was only one study, with few participants and events, and there was no information about how data from people who withdrew were analysed. AUTHORS' CONCLUSIONS There is insufficient evidence to support or refute the suggestion that fentanyl works in any neuropathic pain condition

Mercado y centro deportivo en la plaza de la Cebada, Madrid

Mercado y centro deportivo en la plaza de la Cebada, Madrid. Convocatoria Febrero. Plan 1996. Proyecto fin de carrera. Universidad Politécnica de Madrid. Escuela Técnica Superior de Arquitectur