One-Loop QCD Spin Chain and its Spectrum

We study the renormalization of gauge invariant operators in large Nc QCD. We compute the complete matrix of anomalous dimensions to leading order in the 't Hooft coupling and study its eigenvalues. Thinking of the mixing matrix as the Hamiltonian of a generalized spin chain we find a large integrable sector consisting of purely gluonic operators constructed with self-dual field strengths and an arbitrary number of derivatives. This sector contains the true ground state of the spin chain and all the gapless excitations above it. The ground state is essentially the anti-ferromagnetic ground state of a XXX1 spin chain and the excitations carry either a chiral spin quantum number with relativistic dispersion relation or an anti-chiral one with non-relativistic dispersion relation.Comment: 54 pages, v2: minor changes, references adde

The Efficacy of Chat Sheets as a Conversation Tool For Communicative Access in Aphasia: A Single-Subject Study

Adults with aphasia are frequently denied communicative access in family events, discussions, and daily decision-making. Consequently, recent studies have investigated conversational language interventions for individuals with aphasia (IWA) and their families. Aphasiologists support the use of communication partner (CP) training as an intervention method—through which, people around the IWA learn to use strategies and resources to facilitate successful, interactive communication. While CP training alone can be effective, family members of an IWA may benefit from the use of a supplemental conversation tool to bridge the gap between strategy training and implementation. The purpose of this single-subject A1-B-A2 study was to investigate the efficacy of “Chat Sheets” as a visual tool for facilitating multi-modal communication and improved dyadic comprehension. One dyad (an IWA and his spouse) participated in the study. An initial CP training session was provided for the spouse focusing on Supportive Conversation for Adults with Aphasia (SCA) strategies (Kagan, 1999)—after which the dyad engaged in 10 video-recorded conversations throughout baseline, experimental, and final baseline probes. All conversations were scored by blind raters and an informal interview was conducted at the end of the study

A BeppoSAX observation of the super-soft source CAL87

We report on a BeppoSAX Concentrator Spectrometer observation of the super-soft source (SSS) CAL87. The X-ray emission in SSS is believed to arise from nuclear burning of accreted material on the surface of a white dwarf (WD). An absorbed blackbody spectral model gives a chi^2_v of 1.18 and a temperature of 42 +/- ^13 _11 eV. However, the derived luminosity and radius are greater than the Eddington limit and radius of a WD. Including an O viii edge at 0.871 keV gives a significantly better fit (at > 95% confidence) and results in more realistic values of the source luminosity and radius. We also fit WD atmosphere models to the CAL87 spectrum. These also give reasonable bolometric luminosities and radii in the ranges 2.7-4.8 10^{36} erg/s and 8-20 10^7 cm, respectively. These results support the view that the X-ray emission from CAL87 results from nuclear burning in the atmosphere of a WD.Comment: 4 pages. Accepted for publication in A&A (Letters

Vaccine-induced skewing of T cell responses protects against Chikungunya virus disease

Chikungunya virus (CHIKV) infections can cause severe and debilitating joint and muscular pain that can be long lasting. Current CHIKV vaccines under development rely on the generation of neutralizing antibodies for protection; however, the role of T cells in controlling CHIKV infection and disease is still unclear. Using an overlapping peptide library, we identified the CHIKV-specific T cell receptor epitopes recognized in C57BL/6 infected mice at 7 and 14 days post-infection. A fusion protein containing peptides 451, 416, a small region of nsP4, peptide 47, and an HA tag (CHKVf5) was expressed using adenovirus and cytomegalovirus-vectored vaccines. Mice vaccinated with CHKVf5 elicited robust T cell responses to higher levels than normally observed following CHIKV infection, but the vaccine vectors did not elicit neutralizing antibodies. CHKVf5-vaccinated mice had significantly reduced infectious viral load when challenged by intramuscular CHIKV injection. Depletion of both CD

XTE J1739-302: An Unusual New X-ray Transient

A new x-ray transient, designated XTE J1739-302, was discovered with the Proportional Counter Array (PCA) on the Rossi X-ray Timing Explorer (RXTE) in data from 12 August 1997. Although it was the brightest source in the Galactic Center region while active (about 3.0 x 10^-9 ergs/cm2/s from 2 to 25 keV), it was only observed on that one day; it was not detectable nine days earlier or two days later. There is no known counterpart at other wavelengths, and its proximity to the Galactic Center will make such an identification difficult due to source confusion and extinction. The x-ray spectrum and intensity suggest a giant outburst of a Be/neutron star binary, although no pulsations were observed and the outburst was shorter than is usual from these systems.Comment: 11 pages incorporating 6 figures, AAStex; accepted for The Astrophysical Journal, Part 2 (Letters

Protocol TOP-Study (tacrolimus organ perfusion): a prospective randomized multicenter trial to reduce ischemia reperfusion injury in transplantation of marginal liver grafts with an "ex vivo" tacrolimus perfusion

Background: Critical organ shortage results in the utilization of extended donor criteria (EDC) liver grafts. These marginal liver grafts are prone to increased ischemia reperfusion injury (IRI) which may contribute to deteriorated graft function and survival. Experimental data have shown that the calcineurin inhibitor tacrolimus exerts protective effects on hepatic IRI when applied intravenously or directly as a hepatic rinse. Therefore, the aim of the present study is to examine the effects of an ex vivo tacrolimus perfusion on IRI in transplantation of EDC liver grafts. Methods/Design: The TOP-Study (tacrolimus organ perfusion) is a randomized multicenter trial comparing the ex vivo tacrolimus perfusion of marginal liver grafts with placebo. We hypothesize that a tacrolimus rinse reduces IRI, potentially improving organ survival following transplantation of EDC livers. The study includes livers with two or more EDC, according to Eurotransplant International Foundation’s definition of EDC livers. Prior to implantation, livers randomized to the treatment group are rinsed with tacrolimus at a concentration of 20 ng/ml in 1000 ml Custodiol solution and in the placebo group with Custodiol alone. The primary endpoint is the maximum serum alanine transamninase (ALT) level within the first 48 hours after surgery; however, the study design also includes a 1-year observation period following transplantation. The TOP-Study is an investigator-initiated trial sponsored by the University of Munich Hospital. Seven other German transplant centers are participating (Berlin, Frankfurt, Heidelberg, Mainz, Münster, Regensburg, Tübingen) and aim to include a total of 86 patients. Discussion: Tacrolimus organ perfusion represents a promising strategy to reduce hepatic IRI following the transplantation of marginal liver grafts. This treatment may help to improve the function of EDC grafts and therefore safely expand the donor pool in light of critical organ shortage. Trial register: EudraCT number: 2010-021333-31, ClinicalTrials.gov identifier: NCT0156409

Is transactional sex exploitative? A social norms perspective, with implications for interventions with adolescent girls and young women in Tanzania

Although transactional sex is common in many sexual relationships, there has been little research into the degree to which the practice is considered exploitative in the settings in which it is practiced. We describe the social norms that influence transactional sex in two sites in Mwanza, Tanzania, and explore local understandings of whether and under what conditions it is considered exploitative. We then compare these "emic" understandings of exploitation to international definitions and norms around sexual exploitation. This study employed a qualitative research design involving 18 focus group discussions and 43 in-depth interviews with young people aged 14-24 years and parents with children aged 14-24 years in a rural area and an urban center within Mwanza, Tanzania. Thematic analysis was conducted with the aid of NVivo 10. The social norms influencing the practice of transactional sex included: reciprocity as a core cultural value that permeates the way exchange in sexual relationships is judged; gendered expectations that men should provide for women's material needs in sexual relationships and that women should reciprocate by means of sex; and peer pressure to be perceived as "fashionable". Adolescent girls and young women (AGYW) are under strong peer pressure to conform to a "modern lifestyle" as reflected in stylish clothing and other items of modernity such as cellphones. The emic conceptualization of exploitation is defined by circumstances surrounding the relationship or a sexual encounter. Important factors that characterize local notions of when transactional relationships are considered exploitative include: when the encounter or relationship involves an imbalance of power (based on age, male economic power and social status); when a man fails to reciprocate; and when sex is coerced. According to community perspectives, young women's behavior should be considered exploitative of men when they take gifts or money yet refuse sex or when they demand large sums of money. Interventions aimed at reducing AGYW's exploitation through transactional sex need to be cognizant of the variations in the understanding of what constitutes sexual exploitation as well as the social and gender norms influencing the practice of transactional sex. Interventions need to involve communities and families in critical thinking that helps them identify positive alternatives to current gendered social norms that shape the involvement of AGYW and men in transactional sex

Mannose binding lectin is required for alphavirus-induced arthritis/myositis

Mosquito-borne alphaviruses such as chikungunya virus and Ross River virus (RRV) are emerging pathogens capable of causing large-scale epidemics of virus-induced arthritis and myositis. The pathology of RRV-induced disease in both humans and mice is associated with induction of the host inflammatory response within the muscle and joints, and prior studies have demonstrated that the host complement system contributes to development of disease. In this study, we have used a mouse model of RRV-induced disease to identify and characterize which complement activation pathways mediate disease progression after infection, and we have identified the mannose binding lectin (MBL) pathway, but not the classical or alternative complement activation pathways, as essential for development of RRV-induced disease. MBL deposition was enhanced in RRV infected muscle tissue from wild type mice and RRV infected MBL deficient mice exhibited reduced disease, tissue damage, and complement deposition compared to wild-type mice. In contrast, mice deficient for key components of the classical or alternative complement activation pathways still developed severe RRV-induced disease. Further characterization of MBL deficient mice demonstrated that similar to C3(-/-) mice, viral replication and inflammatory cell recruitment were equivalent to wild type animals, suggesting that RRV-mediated induction of complement dependent immune pathology is largely MBL dependent. Consistent with these findings, human patients diagnosed with RRV disease had elevated serum MBL levels compared to healthy controls, and MBL levels in the serum and synovial fluid correlated with severity of disease. These findings demonstrate a role for MBL in promoting RRV-induced disease in both mice and humans and suggest that the MBL pathway of complement activation may be an effective target for therapeutic intervention for humans suffering from RRV-induced arthritis and myositis.This work was supported by NIH/NIAMS R01 AR 047190 awarded to MTH