Proximity effect in Nb-Mo layered films: Transition temperature and critical current dependence on period

The behavior of the transition temperature and critical current density for a Mo/Nb repeated bilayer system as a function of the number of periods was explored. The measured values of the transition temperature are compared to the theoretical predictions for the proximity effect in the dirty limit. We find that the transition temperature does not decrease as the number of periods increase. In addition, inductive critical current density measurements also show a scaling that indicates the superconductivity properties are not dependent on the number of bilayers.Comment: 13 pages, 6 figures, to be published Journal of Applied Physic

Latent HIV-1 infection in enriched populations of blood monocytes and T cells from seropositive patients

The extent of latent HIV-1 infection in blood T cells and monocytes of 23 seropositive individuals was examined using DNA amplification (PCR) of HIV-1 sequences. Amplified DNA was found in at least one cell type in all seropositives tested, including 13 asymptomatic, 5 ARC, and 5 AIDS patients. Amplification with two or more primer sets from the gag, env, LTR occurred in 21 (91%) patients\u27 T cells and 17 (74%) patients\u27 monocytes. However, amplification with the LTR primers n monocytes was uncommon. Among four patients tested, amplified DNA continued to be detected after a greater than one thousand-fold dilution (\u3c 500 cells) of both T cell and monocyte lysates. Repeat analysis after 7-9 mo in five seropositives yielded similar findings in T cells and monocytes, but some variation in the efficacy of amplification with individual primers occurred. There was no difference in those 10 patients who were taking AZT, compared to those who were untreated. Our results indicate that a fraction (\u3c 1%) of both T cells and monocytes in blood carry a latent infection in all stages of HIV-1 disease and can serve as reservoirs throughout AZT therapy

Drug Treatment Program Ownership, Medicaid Acceptance, and Service Provision.

The Institute of Medicine noted that effective substance abuse treatment (SAT) programs integrate individual therapeutic approaches with transitional/ancillary services. In addition, research suggests that type of ownership impacts SAT services offered and that Medicaid plays a key role in SAT access. Data from the National Survey of Substance Abuse Treatment Services for the years 2000 and 2002–2006 were used to examine relationships among SAT program Medicaid acceptance, program ownership, and transitional/ancillary service accessibility. Multivariate logistic regression models controlling for state- and program-level contextual factors were used to analyze the data. Nonprofit SAT programs were significantly more likely to offer transitional/ancillary services than for-profit programs. However, programs that accepted Medicaid, regardless of ownership, were significantly more likely to offer most transitional/ancillary services. The data suggest that Medicaid may play a significant role in offering key transitional/ancillary services related to successful treatment outcome, regardless of program ownership type

The Higgs Sector in a U(1)′U(1)^\prime Extension of the MSSM

We consider the Higgs sector in an extension of the MSSM with extra SM singlets, involving an extra $U(1)^\prime$ gauge symmetry, in which the domain-wall problem is avoided and the effective $\mu$ parameter is decoupled from the new gauge boson $Z^\prime$ mass. The model involves a rich Higgs structure very different from that of the MSSM. In particular, there are large mixings between Higgs doublets and the SM singlets, significantly affecting the Higgs spectrum, production cross sections, decay modes, existing exclusion limits, and allowed parameter range. Scalars considerably lighter than the LEP2 bound (114 GeV) are allowed, and the range $\tan \beta \sim 1$ is both allowed and theoretically favored. Phenomenologically, we concentrate our study on the lighter (least model-dependent, yet characteristic) Higgs particles with significant SU(2)-doublet components to their wave functions, for the case of no explicit CP violation in the Higgs sector. We consider their spectra, including the dominant radiative corrections to their masses from the top/stop loop. We computed their production cross sections and reexamine the existing exclusion limits at LEP2. We outline the searching strategy for some representative scenarios at a future linear collider. We emphasize that gaugino, Higgsino, and singlino decay modes are indicative of extended models and have been given little attention. We present a comprehensive list of model scenarios in the Appendices.Comment: 49 pages, 17 figure

Young adult longitudinal patterns of marijuana use among US National samples of 12th grade frequent marijuana users: a repeatedâ measures latent class analysis

Background and AimsLongâ term frequent marijuana use is associated with significant negative outcomes, yet little is known about the longitudinal course of marijuana use among those who start frequent use during adolescence. Objectives are (a) to identify latent patterns of withinâ person marijuana use from ages 19â 30 years among 12th graders reporting frequent marijuana use, (b) to examine if membership in identified patterns has changed across historical time and (c) to examine if key covariates differentiate class membership.Design, Setting, ParticipantsLongitudinal, national US panel data from 4423 individuals [53.4% of the eligible sample; 2744 (62%) males] who reported frequent marijuana use in 12th grade (modal age 18 years; senior year cohorts 1976â 2006) followed biennially from ages 19/20 to 29/30.MeasurementsSelfâ reported past 30â day marijuana use (frequent use defined as use on 20+ occasions), demographics, college graduation, marriage and parenthood.FindingsRepeatedâ measures latent class analysis (RMLCA) identified five latent classes of past 30â day marijuana use from ages 19/20 to 29/30: continued frequent users (estimated membership 23.4%); frequent to nonâ frequent users (15.5%); consistent nonâ frequent users (18.4%); nonâ frequent users to discontinuers (19.5%); and discontinuers (23.2%). In multivariable models, membership in the highestâ risk latent class (continued frequent users) versus one or more of the lowerâ risk latent classes was more likely for recent cohorts (P = 0.038 to <0.001), as well as those who did not marry (P = 0.039 to < 0.001) or become parents (P = 0.001) by modal age 29/30.ConclusionsNearly one in four 12th grade (modal age 18 years) frequent marijuana users in the US continues to report high frequency use to age 30; the proportion continuing high frequency use across young adulthood has increased among more recent cohorts.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149218/1/add14548_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149218/2/add14548.pd

Large-Mass Ultra-Low Noise Germanium Detectors: Performance and Applications in Neutrino and Astroparticle Physics

A new type of radiation detector, a p-type modified electrode germanium diode, is presented. The prototype displays, for the first time, a combination of features (mass, energy threshold and background expectation) required for a measurement of coherent neutrino-nucleus scattering in a nuclear reactor experiment. The device hybridizes the mass and energy resolution of a conventional HPGe coaxial gamma spectrometer with the low electronic noise and threshold of a small x-ray semiconductor detector, also displaying an intrinsic ability to distinguish multiple from single-site particle interactions. The present performance of the prototype and possible further improvements are discussed, as well as other applications for this new type of device in neutrino and astroparticle physics (double-beta decay, neutrino magnetic moment and WIMP searches).Comment: submitted to Phys. Rev.

Initial determination of the spins of the gluino and squarks at LHC

In principle particle spins can be measured from their production cross sections once their mass is approximately known. The method works in practice because spins are quantized and cross sections depend strongly on spins. It can be used to determine, for example, the spin of the top quark. Direct application of this method to supersymmetric theories will have to overcome the challenge of measuring mass at the LHC, which could require high statistics. In this article, we propose a method of measuring the spins of the colored superpatners by combining rate information for several channels and a set of kinematical variables, without directly measuring their masses. We argue that such a method could lead to an early determination of the spin of gluino and squarks. This method can be applied to the measurement of spin of other new physics particles and more general scenarios.Comment: 23 pages, 8 figures, minor change

Searching for the light dark gauge boson in GeV-scale experiments

We study current constraints and search prospects for a GeV scale vector boson at a range of low energy experiments. It couples to the Standard Model charged particles with a strength <= 10^-3 to 10^-4 of that of the photon. The possibility of such a particle mediating dark matter self-interactions has received much attention recently. We consider searches at low energy high luminosity colliders, meson decays, and fixed target experiments. Based on available data, searches both at colliders and in meson decays can discover or exclude such a scenario if the coupling strength is on the larger side. We emphasize that a dedicated fixed target experiment has a much better potential in searching for such a gauge boson, and outline the desired properties of such an experiment. Two different optimal designs should be implemented to cover the range of coupling strength 10^-3 to 10^-5, and < 10^-5 of the photon, respectively. We also briefly comment on other possible ways of searching for such a gauge boson.Comment: 33 pages, 5 figures; v2: corrected discussion of Upsilon decays, updates to discussion of fixed-target experiments and QED constraints, numerous minor changes, references added; v3: typo corrected relative to the JHEP published versio