Degenerate Stars and Gravitational Collapse in AdS/CFT

We construct composite CFT operators from a large number of fermionic primary fields corresponding to states that are holographically dual to a zero temperature Fermi gas in AdS space. We identify a large N regime in which the fermions behave as free particles. In the hydrodynamic limit the Fermi gas forms a degenerate star with a radius determined by the Fermi level, and a mass and angular momentum that exactly matches the boundary calculations. Next we consider an interacting regime, and calculate the effect of the gravitational back-reaction on the radius and the mass of the star using the Tolman-Oppenheimer-Volkoff equations. Ignoring other interactions, we determine the "Chandrasekhar limit" beyond which the degenerate star (presumably) undergoes gravitational collapse towards a black hole. This is interpreted on the boundary as a high density phase transition from a cold baryonic phase to a hot deconfined phase.Comment: 75 page

'Prechronous' metastasis in clear cell renal cell carcinoma: a case report

<p>Abstract</p> <p>Introduction</p> <p>Although metastatic carcinoma in the presence of an occult primary tumor is well recognized, underlying reasons for the failure of the primary tumor to manifest are uncertain. Explanations for this phenomenon have ranged from spontaneous regression of the primary tumor to early metastasis of the primary tumor before manifestation of a less aggressive primary tumor. We report a case of 'prechronous' metastasis arising from clear cell renal cell carcinoma, where metastatic disease initially manifested in the absence of a primary renal tumor, followed by aggressive growth of the primary renal lesion.</p> <p>Case presentation</p> <p>A 43-year-old Malay man initially presented to our facility with fever and cough. He subsequently underwent surgical resection of a 9 cm right-sided lung mass found on radiological examination. Histology showed a high-grade clear cell tumor with sarcomatoid differentiation, suggestive of a metastasis from clear cell renal cell carcinoma. However, no concurrent renal lesions were noted on computed tomographic evaluation at that time. Then, four months after lung resection, he presented with a subcutaneous mass in the left loin, as well as right loin discomfort. Computed tomography scanning revealed a 10 cm right renal mass, with renal vein and inferior vena cava invasion, as well as recurrent disease in the right thorax. Histological examination of the excised subcutaneous mass revealed a high-grade carcinoma consistent with clear cell renal cell carcinoma.</p> <p>Conclusions</p> <p>This is the first reported case of prechronous metastasis of renal cell carcinoma, with metastatic disease manifesting prior to the development of the primary lesion. The underlying mechanism is uncertain, but our patient's case provides anecdotal support for the early dissemination model of metastasis.</p

Physics of Neutron Star Crusts

The physics of neutron star crusts is vast, involving many different research fields, from nuclear and condensed matter physics to general relativity. This review summarizes the progress, which has been achieved over the last few years, in modeling neutron star crusts, both at the microscopic and macroscopic levels. The confrontation of these theoretical models with observations is also briefly discussed.Comment: 182 pages, published version available at <http://www.livingreviews.org/lrr-2008-10

A follow-up study of heroin addicts (VEdeTTE2): study design and protocol

BACKGROUND: In Italy, a large cohort study (VEdeTTE1) was conducted between 1998–2001 to evaluate the effectiveness of treatments in reducing mortality and increasing treatment retention among heroin addicts. The follow-up of this cohort (VEdeTTE2) was designed to evaluate the effectiveness of treatments on long-term outcomes, such as rehabilitation and social re-integration. The purpose of this paper is to describe the protocol of the VEdeTTE2 study, and to present the results of the pilot study carried out to assess the feasibility of the study and to improve study procedures. METHODS: The source population for the VEdeTTE2 study was the VEdeTTE1 cohort, from which a sample of 2,200 patients, traced two or more years after enrolment in the cohort, were asked to participate. An interview investigates drug use; overdose; family and social re-integration. Illegal activity are investigated separately in a questionnaire completed by the patient. Patients are also asked to provide a hair sample to test for heroin and cocaine use. Information on treatments and HIV, HBV and HCV morbidity are obtained from clinical records. A pilot phase was planned and carried out on 60 patients. RESULTS: The results of the pilot phase pointed out the validity of the procedures designed to limit attrition: the number of traced subjects was satisfactory (88%). Moreover, the pilot phase was very useful in identifying possible causes of delays and attrition, and flaws in the instruments. Improvements to the procedures and the instruments were subsequently implemented. Sensitivity of the biological test was quite good for heroin (78%) but lower for cocaine (42.3%), highlighting the need to obtain a hair sample from all patients. CONCLUSION: In drug addiction research, studies investigating health status and social re-integration of subjects at long-term follow-up are lacking. The VEdeTTE2 study aims to investigate these outcomes at long-term follow-up. Results of the pilot phase underline the importance of the pilot phase when planning a follow-up study

Futures trading, spot price volatility and market efficiency: evidence from European real estate securities futures

In 2007 futures contracts were introduced based upon the listed real estate market in Europe. Following their launch they have received increasing attention from property investors, however, few studies have considered the impact their introduction has had. This study considers two key elements. Firstly, a traditional Generalized Autoregressive Conditional Heteroskedasticity (GARCH) model, the approach of Bessembinder & Seguin (1992) and the Gray’s (1996) Markov-switching-GARCH model are used to examine the impact of futures trading on the European real estate securities market. The results show that futures trading did not destabilize the underlying listed market. Importantly, the results also reveal that the introduction of a futures market has improved the speed and quality of information flowing to the spot market. Secondly, we assess the hedging effectiveness of the contracts using two alternative strategies (naïve and Ordinary Least Squares models). The empirical results also show that the contracts are effective hedging instruments, leading to a reduction in risk of 64 %

The Making of a Monster: Postnatal Ontogenetic Changes in Craniomandibular Shape in the Great Sabercat Smilodon

Derived sabercats had craniomandibular morphologies that in many respects were highly different from those of extant felids, and this has often been interpreted functionally as adaptations for predation at extreme gape angles with hypertrophied upper canines. It is unknown how much of this was a result of intraspecific postnatal ontogeny, since juveniles of sabercats are rare and no quantitative study has been made of craniomandibular ontogeny. Postnatal ontogenetic craniomandibular shape changes in two morphologically derived sabercats, Smilodon fatalis and S. populator, were analysed using geometric morphometrics and compared to three species of extant pantherines, the jaguar, tiger, and Sunda clouded leopard. Ontogenetic shape changes in Smilodon usually involved the same areas of the cranium and mandible as in extant pantherines, and large-scale modularization was similar, suggesting that such may have been the case for all felids, since it followed the same trends previously observed in other mammals. However, in other respects Smilodon differed from extant pantherines. Their crania underwent much greater and more localised ontogenetic shape changes than did the mandibles, whereas crania and mandibles of extant pantherines underwent smaller, fewer and less localised shape changes. Ontogenetic shape changes in the two species of Smilodon are largely similar, but differences are also present, notably those which may be tied to the presence of larger upper canines in S. populator. Several of the specialized cranial characters differentiating adult Smilodon from extant felids in a functional context, which are usually regarded as evolutionary adaptations for achieving high gape angles, are ontogenetic, and in several instances ontogeny appears to recapitulate phylogeny to some extent. No such ontogenetic evolutionary adaptive changes were found in the extant pantherines. Evolution in morphologically derived sabercats involved greater cranial ontogenetic changes than among extant felids, resulting in greatly modified adult craniomandibular morphologies

Hyaluronic acid covers in burn treatment: a systematic review

Abstract OBJECTIVE To evaluate the effectiveness of hyaluronic acid in the healing of partial thickness burns. METHOD Systematic review of randomized controlled trials on the use of hyaluronic acid for the topical treatment of skin burns, based on recommendations of the Cochrane Handbook for Systematic Reviews of Interventions. RESULTS Two randomized controlled trials that analyzed 143 patients with partial thickness burns and/or deep partial thickness burns were selected. They compared the application of hyaluronic acid 0.2% associated to silver sulfadiazine 1% 5g/cm2 versus silver sulfadiazine 1% 5g/cm2 alone for the outcome of complete healing. CONCLUSION This review emphasizes the need for new well-designed randomized controlled trials to establish the therapeutic relevance of hyaluronic acid with respect to the healing of burns of partial thickness or deep partial thickness

Exploring new physics frontiers through numerical relativity

The demand to obtain answers to highly complex problems within strong-field gravity has been met with significant progress in the numerical solution of Einstein's equations - along with some spectacular results - in various setups. We review techniques for solving Einstein's equations in generic spacetimes, focusing on fully nonlinear evolutions but also on how to benchmark those results with perturbative approaches. The results address problems in high-energy physics, holography, mathematical physics, fundamental physics, astrophysics and cosmology