6,276 research outputs found
Comment on Leptophobic Bosons and Neutral Current Scattering Data
The relevance of existing deep inelastic scattering data to models
containing a leptophobic neutral vector boson is discussed. It is shown that
this neutral current data is in good agreement with the Standard Model and
disfavors such a leptophobic boson.Comment: LaTeX, 3 pages, 1 embedded PS figure, available at
http://cordelia.fnal.gov/~ksmcf/publications/moriond_comment.ps.gz .
Presented at the XXXIieme Rencontres de Moriond, Electroweak Interactions and
Unified Theorie
A Precision Measurement of Electroweak Parameters in Neutrino-Nucleon Scattering
The CCFR collaboration reports a precise measurement of electroweak
parameters derived from the ratio of neutral-current to charged-current
cross-sections in neutrino-nucleon scattering at the Fermilab Tevatron. This
ratio of cross-sections measures the neutral current couplings to quarks, which
implies a determination of sin^2 theta_W (on-shell) = 0.2236 +/- 0.0028(expt.)
+/- 0.0030(model) for m_top=175 GeV, m_Higgs=150 GeV. This is equivalent to
M_W=80.35+/-0.21 GeV. The good agreement of this measurement with Standard
Model expectations implies the exclusion of additional
neutrino-neutrino-quark-quark contact interactions at 95% confidence at a mass
scale of 1-8 TeV, depending on the form of the contact interaction.Comment: formatted in revtex, 5 pages, 3 eps figures included via psfig,
submitted to Physical Review Letter
High mobility two-dimensional electron system on hydrogen-passivated silicon(111) surfaces
We have fabricated and characterized a field-effect transistor in which an
electric field is applied through an encapsulated vacuum cavity and induces a
two-dimensional electron system on a hydrogen-passivated Si(111) surface. This
vacuum cavity preserves the ambient sensitive surface and is created via room
temperature contact bonding of two Si substrates. Hall measurements are made on
the H-Si(111) surface prepared in aqueous ammonium fluoride solution. We obtain
electron densities up to cm and peak mobilities of
cm/V s at 4.2 K.Comment: to appear in Applied Physics Letter
A Blacker List of Crime Was Never Looked Upon : Mormon Violence, Utah Statehood, and the Memory of the Mountain Meadows Massacre
Neutrino Scattering in a Magnetic Field
Motivated by the evidence for a finite neutrino mass we examine anew the
interaction of neutrinos in a magnetic field. We present the rate for radiative
scattering for both massless and massive neutrinos in the standard model and
give the corresponding numerical estimates. We also consider the effects
arising from a possible neutrino magnetic moment.Comment: 10 pages, 3 figures; Acknowledgements added 05.07.200
Antiretroviral drug resistance mutations in naïve and experienced patients in Shiraz, Iran, 2014
Resistance to antiretroviral agents is a significant concern in the clinical management of HIV-infected individuals, particularly in areas of the world where treatment options are limited. In this study, we aimed to identify HIV drug-resistance-associated mutations in 40 drug-naïve patients and 62 patients under antiretroviral therapy (ART) referred to the Shiraz HIV/AIDS Research Center – the first such data available for the south of Iran. HIV reverse transcriptase and protease genes were amplified and sequenced to determine subtypes and antiretroviral- resistance-associated mutations (RAMs). Subtype CRF35-AD recombinant was the most prevalent in all patients (98 of 102, 96 % ), followed by subtype A1, and subtype B (one each, 2 % ). Among the 40 ART-naïve patients, two mutations associated with nucleoside reverse transcriptase inhibitor (NRTI) resistance (two with Y115F and T215I) and three associated with non-nucleoside reverse transcriptase inhibitor (NNRTI) resistance (two with G190S and Y181C, four with V179T) were found. Among ART-experienced patients, four mutations associated with resistance to NRTI, four with NNRTI, and five with protease inhibitors (PI) were found. Twenty patients with high levels of resistance were already on second-line therapy. We document for the first time in this region of Iran high levels of ART resistance to multiple drugs. Our findings call for more vigilant systematic ART resistance surveillance, increased resistance testing, careful management of patients with existing regimens, and strong advocacy for expansion of available drugs in Iran. © 2016, Springer-Verlag Wien
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