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

On the Hagedorn temperature in holographic confining gauge theories

Abstract The divergence of the string partition function due to the exponential growth of states is a well-understood issue in flat spacetime. It can be interpreted as the appearance of tachyon modes above a certain temperature, known as the Hagedorn temperature T H . In the literature, one can find some intuitions about its generalization to curved spacetimes, where computations are extremely hard and explicit results cannot be provided in general. In this paper, we present a genus-zero estimate of T H , at leading order in α′, for string theories on curved backgrounds holographically dual to confining gauge theories. This is a particularly interesting case, since the holographic correspondence equates T H with the Hagedorn temperature of the dual gauge theories. For concreteness we focus on Type IIA string theory on a well known background dual to an SU(N) Yang-Mills theory. The resulting Hagedorn temperature turns out to be proportional to the square root of the Yang-Mills confining string tension. The related coefficient, which at leading order is analytically determined, is the same as the one for Type II theories in flat space. While the calculation is performed in a specific model, the result applies in full generality to confining gauge theories with a top-down holographic dual

Caudal analgesia in children: S(+)-ketamine vs S(+)-ketamine plus clonidine

Background: The aim of this study was to evaluate postoperative analgesia provided by caudal S(+)-ketamine and S(+)-ketamine plus clonidine without local anesthetic. Methods: Forty-four children aged 1-5 years consecutively scheduled for inguinal hernia repair, hydrocele repair or orchidopexy were randomly assigned to receive a caudal injection of either S(+)-ketamine 1 mg.kg(-1) (group K) or S(+)-ketamine 0.5 mg.kg(-1) plus clonidine 1 mug.kg(-1) (group KC). Postoperative analgesia and sedation were evaluated by CHEOPS and Ramsay scale from emergence from general anesthesia for 24 h. Results: No statistical difference was observed between study groups with respect to pain and sedation assessment. A slight trend toward a reduced requirement for rescue analgesia in group KC was observed, although not statistically significant. Conclusions: Caudal S(+)-ketamine 1 mg.kg(-1) and S(+)-ketamine 0.5 mg.kg(-1) plus clonidine 1 mug.kg(-1) are safe and provide effective postoperative analgesia in children without adverse effects

Influenza A H1N1 and severe asthma exacerbation

The pandemic influenza A H1N1 will affect millions of subjects. This influenza can cause respiratory complications with possible death. We have described two case reports of acute severe asthma exacerbation combined to influenza A H1N1, caracterized by severe respiratory failure. The diagnosis of influenza A H1N1 was confirmed with the multiplex reverse transcription-polymerase chain reaction (RT-PCR) assay. These patients, apart from asthma, do not have other diseases; but they did not take adequate therapy. In addition to conventional therapy (corticosteroids, bronchodilator and antibiotics) oseltamivir 75 mg bid was immediately added. After few days the patients improved and therefore in a short time they were discharged. During this period, in the case of severe asthma exacerbations, one must always think of influenza A H1N1 as the possible cause. It is necessary to use oseltamivir precociously to avoid severe complications. All asthmatic patients must regularly take their therapy especially during pandemic influenza A H1N1