Constructing free actions of p-groups on products of spheres

We prove that, for p an odd prime, every finite p-group of rank 3 acts freely on a finite complex X homotopy equivalent to a product of three spheres

Exotic hybrid mesons with light quarks

Hybrid mesons, made from a quark, an antiquark and gluons, can have quantum numbers inaccessible to conventional quark-antiquark states. Confirmation of such states would give information on the role of "dynamical" color in low energy QCD. We present preliminary results for hybrid meson masses using light Wilson valence quarks.Comment: 4 pages, 4 figures, Talk presented at LATTICE96(spectrum

Heavy-light decay constants---MILC results with the Wilson action

We present the current status of our ongoing calculations of pseudoscalar meson decay constants for mesons that contain one light and one heavy quark (f_B, f_{B_s}, f_D, f_{D_s}). We are currently generating new gauge configurations that include dynamical quarks and calculating the decay constants. In addition, we have several new results for the static approximation. Those results, as well as several refinements to the analysis, are new since Lattice '96. Our current (still preliminary) value for f_B is 156 +- 11 +- 30 +- 14 MeV, where the first error is from statistical and fitting errors, the second error is an estimate of other systematic errors within the quenched approximation and the third error is an estimate of the quenching error. For the ratio f_{B_s}/f_B, we get 1.11 +- 0.02 +- 0.03 +- 0.07.Comment: 8 pages, 9 figures, LaTeX, uses espcrs2, epsf, Invited talk presented by S. Gottlieb at Lattice QCD on Parallel Computers, University of Tsukuba, March, 1997, to appear in the proceeding

Scale-up of a decentralized HIV treatment programme in rural KwaZulu-Natal, South Africa: does rapid expansion affect patient outcomes?

OBJECTIVE: To describe the scale-up of a decentralized HIV treatment programme delivered through the primary health care system in rural KwaZulu-Natal, South Africa, and to assess trends in baseline characteristics and outcomes in the study population. METHODS: The programme started delivery of antiretroviral therapy (ART) in October 2004. Information on all patients initiated on ART was captured in the programme database and follow-up status was updated monthly. All adult patients (> or = 16 years) who initiated ART between October 2004 and September 2008 were included and stratified into 6-month groups. Clinical and sociodemographic characteristics were compared between the groups. Retention in care, mortality, loss to follow-up and virological outcomes were assessed at 12 months post-ART initiation. FINDINGS: A total of 5719 adults initiated on ART were included (67.9% female). Median baseline CD4+ lymphocyte count was 116 cells/microl (interquartile range, IQR: 53-173). There was an increase in the proportion of women who initiated ART while pregnant but no change in other baseline characteristics over time. Overall retention in care at 12 months was 84.0% (95% confidence interval, CI: 82.6-85.3); 10.9% died (95% CI: 9.8-12.0); 3.7% were lost to follow-up (95% CI: 3.0-4.4). Mortality was highest in the first 3 months after ART initiation: 30.1 deaths per 100 person-years (95% CI: 26.3-34.5). At 12 months 23.0% had a detectable viral load (> 25 copies/ml) (95% CI: 19.5-25.5). CONCLUSION: Outcomes were not affected by rapid expansion of this decentralized HIV treatment programme. The relatively high rates of detectable viral load highlight the need for further efforts to improve the quality of services

Finite Temperature Lattice QCD with Clover Fermions

We report on our simulation of finite temperature lattice QCD with two flavors of ${\cal O}(a)$ Symanzik-improved fermions and ${\cal O}(a^2)$ Symanzik-improved glue. Our thermodynamic simulations were performed on an $8^3 \times 4$ lattice, and we have performed complementary zero temperature simulations on an $8^3 \times 16$ lattice. We compare our results to those from simulations with two flavors of Wilson fermions and discuss the improvement resulting from use of the improved action.Comment: 3 pages, 4 figures, Talk presented at Lattice 9

Update on the hadron spectrum with two flavors of staggered quarks

We present an update on the MILC Collaboration's light hadron spectrum calculation with two flavors of dynamical, staggered quarks. We present extrapolations of the nucleon to rho mass ratio to the continuum limit for fixed values of the pi to rho mass ratio including the physical one.Comment: 3 pages, LaTex with espcrc2 and epsf, 5 postscript figures included, Lattice '97 Proceeding

Surface-water groundwater interactions in the Middle Rio Grande, NM Implications for bank storage and native species

Riparian zones are important for ecological purposes and ecosystem processes, and are valued for aesthetic, recreational, cultural, and historical reasons. The declining integrity of cottonwood-dominated riparian systems in the Middle Rio Grande (MRG) of central New Mexico has been evident for several decades, of which the largest cause has been the severe alterations riparian hydrology. While cottonwood germination responses to changing flood regimes have been well studied, the response to changing groundwater dynamics - and the suitability of groundwater regimes in the MRG - is less well understood. This study used pressure transducer groundwater datasets installed in the Rio Grande riparian zone by the Bosque Ecosystem Monitoring Program (BEMP) to investigate groundwater behavior in the MRG and its impact on bank storage, cottonwood recruitment, and native riparian integrity. A relational database of BEMP’s groundwater data was constructed, and its utility was assessed. It was concluded that BEMP’s data are largely accurate, with some exceptions. Time series analysis of the data indicated that riparian groundwater responds rapidly to changes in streamflow, and that bank storage is transient and does not extend far from the river channel. This may be caused by agricultural drains, which induce an uncharacteristic permanent hydraulic gradient sloping away from the river. This gradient intercepts bank storage and causes rapid groundwater recessions after high discharge events. At all study sites but one, groundwater recession is controlled directly by the rate of discharge decline, and often exceeded the maximum rate tolerable by cottonwood seedlings. A single successful cottonwood recruitment event in 2009 at one of the sites was captured in the pressure transducer record. Groundwater observations from this event indicate that cottonwood seedlings can tolerate relatively rapid recession rates, as long as these rates are not prolonged, or are interspersed with slower or negligible rates. Ultimately, the primary difference between present day conditions and when large-scale recruitment events occurred is the flow regime of the Rio Grande and loss of high-discharge flood events

Relationships between changes in sustained fronto-striatal connectivity and positive affect with antidepressant treatment in major depression

Objective: Deficits in positive affect and their neural bases have been associated with major depression. However, whether reductions in positive affect result solely from an overall reduction in nucleus accumbens activity and fronto-striatal connectivity or the additional inability to sustain engagement of this network over time is unknown. The authors sought to determine whether treatment-induced changes in the ability to sustain nucleus accumbens activity and fronto-striatal connectivity during the regulation of positive affect are associated with gains in positive affect. Method: Using fMRI, the authors assessed the ability to sustain activity in reward-related networks when attempting to increase positive emotion during per- formance of an emotion regulation para- digm in 21 depressed patients before and after 2 months of antidepressant treat- ment. Over the same interval, 14 healthy comparison subjects underwent scanning as well. Results: After 2 months of treatment, self-reported positive affect increased. The patients who demonstrated the largest increases in sustained nucleus accumbens activity over the 2 months were those who demonstrated the largest increases in positive affect. In addition, the patients who demonstrated the largest increases in sustained fronto-striatal connectivity were also those who demonstrated the largest increases in positive affect when control- ling for negative affect. None of these associations were observed in healthy comparison subjects. Conclusions: Treatment-induced change in the sustained engagement of fronto- striatal circuitry tracks the experience of positive emotion in daily life. Studies examining reduced positive affect in a va- riety of psychiatric disorders might benefit from examining the temporal dynamics of brain activity when attempting to under- stand changes in daily positive affect