Wounded quarks and diquarks in high energy collisions

Particle production in Au-Au, Cu-Cu, d-Au and p-p collisions at 200 GeV c.m. energy are analyzed in the wounded quark-diquark model. Existing data are well reproduced. Emission functions of wounded and unwounded constituents are determined. Implications for the collective evolution of the system are discussed.Comment: version to be published in Phys. Rev. C, minor changes, discussion extende

3D Jet Tomography of Twisted Strongly Coupled Quark Gluon Plasmas

The triangular enhancement of the rapidity distribution of hadrons produced in p+A reactions relative to p+p is a leading order in A^{1/3}/log(s) violation of longitudinal boost invariance at high energies. In A+A reactions this leads to a trapezoidal enhancement of the local rapidity density of produced gluons. The local rapidity gradient is proportional to the local participant number asymmetry, and leads to an effective rotation in the reaction plane. We propose that three dimensional jet tomography, correlating the long range rapidity and azimuthal dependences of the nuclear modification factor, R_{AA}(\eta,\phi,p_\perp; b>0), can be used to look for this intrinsic longitudinal boost violating structure of $A+A$ collisions to image the produced twisted strongly coupled quark gluon plasma (sQGP). In addition to dipole and elliptic azimuthal moments of R_{AA}, a significant high p_\perp octupole moment is predicted away from midrapidity. The azimuthal angles of maximal opacity and hence minima of R_{AA} are rotated away from the normal to the reaction plane by an `Octupole Twist' angle, \theta_3(\eta), at forward rapidities.Comment: 10 Pages, 16 Figures, RevTex, Replaced with Peer reviewed verion for PR

Bulk Viscosity driven clusterization of quark-gluon plasma and early freeze-out in relativistic heavy-ion collisions

We introduce a new scenario for heavy ion collisions that could solve the lingering problems associated with the so-called HBT puzzle. We postulate that the system starts expansion as the perfect quark-gluon fluid but close to freeze-out it splits into clusters, due to a sharp rise of bulk viscosity in the vicinity of the hadronization transition. We then argue that the characteristic cluster size is determined by the viscosity coefficient and the expansion rate. Typically it is much smaller and independent of the total system volume. These clusters maintain the pre-existing outward-going flow, as a spray of droplets, but develop no flow of their own, and hadronize by evaporation. We provide an ansatz for converting the hydrodynamic output into clusters.Comment: Accepted for publication, Phys. Rev. C. Arguments considerably expanded, refined and reworde

Polarization probes of vorticity in heavy ion collisions

We discuss the information that can be deduced from a measurement of particle (hyperon or vector meson) polarization in ultrarelativistic nuclear collisions. We describe the sensitivity of polarization to initial conditions, hydrodynamic evolution and mean free path, and find that the polarization observable is sensitive to all details and stages of the system's evolution. We suggest that an experimental investigation covering production plane and reaction plane polarizations, as well as the polarization of jet-associated particles in the plane defined by the jet and particle direction, can help in disentangling the factors contributing to this observable. Scans of polarization in energy and rapidity might also point to a change in the system's properties.Comment: In press, Phys.Rev.C. One new figure, text streamlined and edited, physics conclusions and reasoning not change

Falling through the gaps: how should HIV programmes respond to families that persistently deny treatment to children?

INTRODUCTION: Children living with HIV rely on adult caregivers for access to HIV testing and care, including clinical monitoring and adherence to treatment. Yet, many caregivers confront barriers to ensuring children's care, including fear of disclosure of the child's or the parents' HIV status, competing family demands, fluctuating care arrangements and broader structural factors such as entrenched poverty or alternative beliefs about HIV's aetiology and treatment. Thus, many children are "falling through the gaps" because their access to testing and care is mediated by guardians who appear unable or unwilling to facilitate it. These children are likely to suffer treatment failure or death due to their caregivers' recalcitrance. DISCUSSION: This Commentary presents three cases from paediatric HIV services in Zimbabwe that highlight the complexities facing health care providers in providing HIV testing and care to children, and discusses the implications as a child's rights issue requiring both legal and programmatic responses. The cases provide examples of how disagreements between family members about appropriate care, conflicts between a child and caregiver and religious objections to medical treatment interrupt children's engagement with HIV services. In all three cases, no social or legal mechanisms were in place for health staff to intervene and prevent "loss to follow up." CONCLUSIONS: We suggest that conceptualizing this as a child's rights issue may be a useful way to raise the debate and move towards improved treatment access. Our cases reflect policy failure to facilitate access to children's HIV testing and treatment, and are likely to be similar across international settings. We propose sharing experiences and encouraging dialogue between health practitioners and global advocates for children's right to health to raise awareness that children are the bearers of rights even if they lack legal capacity, and that the failure of either the state or their caregiver to facilitate access to care is in fact a rights violation

Anisotropic collective phenomena in ultra-relativistic nuclear collisions

For a detailed review of this subject I refer to a recent paper \cite{Voloshin:2008dg}; in this talk I only very briefly comment on a few most important questions: (a) Very recent significant progress in viscous hydrodynamics calculations (b) Initial eccentricity/flow fluctuations, the effect of which has been clarified recently (c) Initial conditions, in particular the role of the gradients in the initial velocity field, (d) Puzzling system size dependence of directed flow (e) Azimuthal correlations that are sensitive to the strong parity violation (f) Future measurements at RHIC and LHC, including pp-collisionsComment: 6 pages. Proceedings. Invited talk at PANIC 2008 conference, Eilat, Israel, November 200

"I will not stop visiting!" a qualitative study of community health workers' reluctance to withdraw household support following the end of a community-based intervention in Zimbabwe.

BACKGROUND: Community Health Worker (CHW) programmes are increasingly important in HIV service delivery. CHWs' familiarity with the local context can improve intervention acceptability and sustainability but concerns have been raised about potential exploitation and "burnout" of CHWs as they become emotionally involved in clients' lives. Little attention has been paid to what happens at the end of time-limited CHW interventions. This study aimed to examine the experience of CHWs' withdrawal from clients and their families. METHODS: We conducted a qualitative study of CHWs' experiences of "exiting" from households during the ZENITH (Zimbabwe Study for Enhancing Testing and Improving Treatment of HIV in Children) intervention, which provided 12 structured home visits over 72 weeks to families with children recently diagnosed with HIV. We conducted semi-structured interviews at 12 and 18 months with all 19 CHWs delivering the intervention and 36 purposively selected caregivers who received home visits. Analysis focused on perceptions of the end of the trial, when CHWs completed the scheduled home-based visits and there was no guarantee of programme continuation beyond the study. RESULTS: Termination of scheduled home visits caused significant distress to both CHWs and the households they visited. We identify 3 thematic "lessons learned" for CHW programmes. First, CHWs derived pride and self-worth from emotional labour as they became integral to families' improved ability to cope, motivating them to go beyond formal job requirements. Second, clients' growing dependence on CHWs led to "exit" being interpreted as abandonment by both CHWs and households, causing distress on both sides. Finally, in response to anxiety about "abandoning" families, CHWs maintained contact with families long after scheduled withdrawal of services. CONCLUSIONS: CHWs can forge genuine bonds with households, creating expectations of long-term engagement. On the positive side, CHW derive pride from their work, attach social responsibility to their roles, and feel personal fulfilment in supporting families. If CHWs do not disengage from interventions as planned, or become demoralised by "exits", interventions will prove less sustainable. CHWs are often lauded for their ability to develop trust with peers, yet this willingness and ability to create enduring emotional bonds could threaten programme delivery

A combined microfinance and training intervention can reduce HIV risk behaviour in young female participants.

OBJECTIVE: To assess effects of a combined microfinance and training intervention on HIV risk behavior among young female participants in rural South Africa. DESIGN: : Secondary analysis of quantitative and qualitative data from a cluster randomized trial, the Intervention with Microfinance for AIDS and Gender Equity study. METHODS: Eight villages were pair-matched and randomly allocated to receive the intervention. At baseline and after 2 years, HIV risk behavior was assessed among female participants aged 14-35 years. Their responses were compared with women of the same age and poverty group from control villages. Intervention effects were calculated using adjusted risk ratios employing village level summaries. Qualitative data collected during the study explored participants' responses to the intervention including HIV risk behavior. RESULTS: After 2 years of follow-up, when compared with controls, young participants had higher levels of HIV-related communication (adjusted risk ratio 1.46, 95% confidence interval 1.01-2.12), were more likely to have accessed voluntary counseling and testing (adjusted risk ratio 1.64, 95% confidence interval 1.06-2.56), and less likely to have had unprotected sex at last intercourse with a nonspousal partner (adjusted risk ratio 0.76, 95% confidence interval 0.60-0.96). Qualitative data suggest a greater acceptance of intrahousehold communication about HIV and sexuality. Although women noted challenges associated with acceptance of condoms by men, increased confidence and skills associated with participation in the intervention supported their introduction in sexual relationships. CONCLUSIONS: In addition to impacts on economic well being, women's empowerment and intimate partner violence, interventions addressing the economic and social vulnerability of women may contribute to reductions in HIV risk behavior

Identified particles in Au+Au collisions at sqrt{s_NN} = 200 GeV

The yields of identified particles have been measured at RHIC for Au+Au collisions at sqrt{s_NN} = 200 GeV using the PHOBOS spectrometer. The ratios of antiparticle to particle yields near mid-rapidity are presented. The first measurements of the invariant yields of charged pions, kaons and protons at very low transverse momenta are also shown.Comment: 4 pages, 4 figures, Contribution to Quark Matter 2002, Nantes, France, July 200

Community health worker support to improve HIV treatment outcomes for older children and adolescents in Zimbabwe: a process evaluation of the ZENITH trial.

BACKGROUND: Community health worker (CHW)-delivered support visits to children living with HIV and their caregivers significantly reduced odds of virological failure among the children in the ZENITH trial conducted in Zimbabwe. We conducted a process evaluation to assess fidelity, acceptability, and feasibility of this intervention to identify lessons that could inform replication and scale-up of this approach. METHODS: Field manuals kept by each CHW, records from monthly supervisory meetings, and participant data collected throughout the trial were used to assess the intervention's implementation. Data extracted from field manuals included visit type, content, and duration. Minutes from monthly supervisory meetings were used to capture CHW attendance. RESULTS: The trial enrolled 172 participants in the intervention arm of whom 5 subsequently refused all visits, 1 died before the intervention could be delivered, and 1 could not be located. Manuals for 8 participants were not returned, 3 were incorrectly entered, and 1 manual was lost. We had 154 manuals available for analysis. A total of 1553 visits were successfully conducted (median 11 per participant, range 1-20). Additionally, CHWs made 85 visits where they were unable to make contact with the family. Thirteen (8.4%) participants received 5 or fewer visits, 10 moved out of the study area, and 3 died. CHWs discussed disclosure with the child/family for over 89% of participants and assisted clients with developing and reviewing their personal treatment plan with over 85% of participants. Of the 20 CHWs (3 male, 17 female) selected to implement the intervention, 19 were retained at the end of the trial. CONCLUSIONS: The intervention was acceptable to participants with most receiving and accepting the required number of visits. Key strenghts were high staff retention and fidelity to the intervention. This community-based intervention was an acceptable and feasible approach to reduce virological failure among children living with HIV. TRIAL REGISTRATION: The ZENITH trial was registered on 25 October 2012 in the Pan African Clinical Trials Registry under the trial registration number PACTR201212000442288 . It can be found at http://www.pactr.org/ATMWeb/appmanager/atm/atmregistry?dar=true&tNo=PACTR201212000442288