1,285 research outputs found
Minimal Trinification
We study the trinified model, SU(3)_C x SU(3)_L x SU(3)_R x Z_3, with the
minimal Higgs sector required for symmetry breaking. There are five Higgs
doublets, and gauge-coupling unification results if all five are at the weak
scale, without supersymmetry. The radiative see-saw mechanism yields sub-eV
neutrino masses, without the need for intermediate scales, additional Higgs
fields, or higher-dimensional operators. The proton lifetime is above the
experimental limits, with the decay modes p -> \bar\nu K^+ and p -> \mu^+ K^0
potentially observable. We also consider supersymmetric versions of the model,
with one or two Higgs doublets at the weak scale. The radiative see-saw
mechanism fails with weak-scale supersymmetry due to the nonrenormalization of
the superpotential, but operates in the split-SUSY scenario.Comment: 23 pages, uses axodra
Photosystem II Peripheral Accessory Chlorophyll Mutants in Chlamydomonas reinhardtii. Biochemical Characterization and Sensitivity to Photo-Inhibition
In addition to the four chlorophylls (Chls) involved in primary charge separation, the photosystem II (PSII) reaction center polypeptides, D1 and D2, coordinate a pair of symmetry-related, peripheral accessory Chls. These Chls are axially coordinated by the D1-H118 and D2-H117 residues and are in close association with the proximal Chl antennae proteins, CP43 and CP47. To gain insight into the function(s) of each of the peripheral Chls, we generated site-specific mutations of the amino acid residues that coordinate these Chls and characterized their energy and electron transfer properties. Our results demonstrate that D1-H118 and D2-H117 mutants differ with respect to: (a) their relative numbers of functional PSII complexes, (b) their relative ability to stabilize charge-separated states, (c) light-harvesting efficiency, and (d) their sensitivity to photo-inhibition. The D2-H117N and D2-H117Q mutants had reduced levels of functional PSII complexes and oxygen evolution capacity as well as reduced light-harvesting efficiencies relative to wild-type cells. In contrast, the D1-H118Q mutant was capable of near wild-type rates of oxygen evolution at saturating light intensities. The D1-H118Q mutant also was substantially more resistant to photo-inhibition than wild type. This reduced sensitivity to photo-inhibition is presumably associated with a reduced light-harvesting efficiency in this mutant. Finally, it is noted that the PSII peripheral accessory Chls have similarities to a to a pair of Chls also present in the PSI reaction center complex
Holographic analysis of diffraction structure factors
We combine the theory of inside-source/inside-detector x-ray fluorescence
holography and Kossel lines/x ray standing waves in kinematic approximation to
directly obtain the phases of the diffraction structure factors. The influence
of Kossel lines and standing waves on holography is also discussed. We obtain
partial phase determination from experimental data obtaining the sign of the
real part of the structure factor for several reciprocal lattice vectors of a
vanadium crystal.Comment: 4 pages, 3 figures, submitte
Neutron time-of-flight measurements of charged-particle energy loss in inertial confinement fusion plasmas
Neutron spectra from secondary ^{3}H(d,n)α reactions produced by an implosion of a deuterium-gas capsule at the National Ignition Facility have been measured with order-of-magnitude improvements in statistics and resolution over past experiments. These new data and their sensitivity to the energy loss of fast tritons emitted from thermal ^{2}H(d,p)^{3}H reactions enable the first statistically significant investigation of charged-particle stopping via the emitted neutron spectrum. Radiation-hydrodynamic simulations, constrained to match a number of observables from the implosion, were used to predict the neutron spectra while employing two different energy loss models. This analysis represents the first test of stopping models under inertial confinement fusion conditions, covering plasma temperatures of k_{B}T≈1-4 keV and particle densities of n≈(12-2)×10^{24} cm^{-3}. Under these conditions, we find significant deviations of our data from a theory employing classical collisions whereas the theory including quantum diffraction agrees with our data
Consistency of cosmic microwave background temperature measurements in three frequency bands in the 2500-square-degree SPT-SZ survey
We present an internal consistency test of South Pole Telescope (SPT)
measurements of the cosmic microwave background (CMB) temperature anisotropy
using three-band data from the SPT-SZ survey. These measurements are made from
observations of ~2500 deg^2 of sky in three frequency bands centered at 95,
150, and 220 GHz. We combine the information from these three bands into six
semi-independent estimates of the CMB power spectrum (three single-frequency
power spectra and three cross-frequency spectra) over the multipole range 650 <
l < 3000. We subtract an estimate of foreground power from each power spectrum
and evaluate the consistency among the resulting CMB-only spectra. We determine
that the six foreground-cleaned power spectra are consistent with the null
hypothesis, in which the six cleaned spectra contain only CMB power and noise.
A fit of the data to this model results in a chi-squared value of 236.3 for 235
degrees of freedom, and the probability to exceed this chi-squared value is
46%.Comment: 21 pages, 4 figures, current version matches version published in
JCA
Generation and analysis of expressed sequence tags (ESTs) for marker development in yam (Dioscorea alata L.)
<p>Abstract</p> <p>Background</p> <p>Anthracnose (<it>Colletotrichum </it><it>gloeosporioides</it>) is a major limiting factor in the production of yam (<it>Dioscorea </it>spp.) worldwide. Availability of high quality sequence information is necessary for designing molecular markers associated with resistance. However, very limited sequence information pertaining to yam is available at public genome databases. Therefore, this collaborative project was developed for genetic improvement and germplasm characterization of yams using molecular markers. The current investigation is focused on studying gene expression, by large scale generation of ESTs, from one susceptible (TDa 95-0310) and two resistant yam genotypes (TDa 87-01091, TDa 95-0328) challenged with the fungus. Total RNA was isolated from young leaves of resistant and susceptible genotypes and cDNA libraries were sequenced using Roche 454 technology.</p> <p>Results</p> <p>A total of 44,757 EST sequences were generated from the cDNA libraries of the resistant and susceptible genotypes. Greater than 56% of ESTs were annotated using MapMan Mercator tool and Blast2GO search tools. Gene annotations were used to characterize the transcriptome in yam and also perform a differential gene expression analysis between the resistant and susceptible EST datasets. Mining for SSRs in the ESTs revealed 1702 unique sequences containing SSRs and 1705 SSR markers were designed using those sequences.</p> <p>Conclusion</p> <p>We have developed a comprehensive annotated transcriptome data set in yam to enrich the EST information in public databases. cDNA libraries were constructed from anthracnose fungus challenged leaf tissues for transcriptome characterization, and differential gene expression analysis. Thus, it helped in identifying unique transcripts in each library for disease resistance. These EST resources provide the basis for future microarray development, marker validation, genetic linkage mapping and QTL analysis in <it>Dioscorea </it>species.</p
Comparable, but distinct: Perceptions of primary care provided by physicians and nurse practitioners in full and restricted practice authority states
AimsTo understand patients- and providers- perceptions of primary care delivered by nurse practitioners (NPs) in the Veterans Affairs Healthcare System.DesignQualitative exploratory study (in convergent mixed- methods design).MethodsSemi- structured interviews in 2016 with primary care providers and patients from facilities in states with full and restricted practice authority for NPs. Patient sample based on reassignment to: (a) a NP; or (b) a different physician following an established physician relationship. Data were analysed using content analysis.ResultsWe interviewed 28 patients, 17 physicians and 14 NPs. We found: (a) NPs provided more holistic care than physicians; (b) patients were satisfied with NPs; and (c) providers- professional experience outweighed provider type.ConclusionsPatients- preferences for NPs (compared with prior physicians) contributed to perceptions of patient centredness. Similarities in providers- perceptions suggest NPs and physicians are both viable providers for primary care.ImpactNurse Practitioners (NPs): practice authorityVeterans Affairs Health care: nurse practitioners will continue to be a viable resource for primary care deliveryUnited States Health care: challenges notions patients may not be satisfied with care provided by NPs and supports expanding their use to provide much- needed access to primary care services; expanding Full Practice Authority would allow states to provide acceptable primary care without diminishing patient or provider experiencesæ è¦ ç ®æ äº è§£æ £è å å »ç æ ºæ 对é ä¼ å äººå »ç ä¿ å ¥ç³»ç» ä¸æ ¤ç å¸ æ ä¾ å çº§æ ¤ç ç ç æ³ ã è®¾è®¡æ ¢ç´¢æ §ç å® æ §ç 究(æ ¶æ æ··å æ ¹æ³ è®¾è®¡)ã æ ¹æ³ 2016å¹´è¿ è¡ ç å ç» æ å è®¿è° ,é è®¿äº å· å æ ¥æ æ ¤ç å¸ ç å ¨ç§ å é å ¨ç§ æ §ä¸ æ ºæ ç å çº§æ ¤ç æ ä¾ è å æ £è ã é æ °å é æ £è æ ·æ ¬:(a) ä¸ å æ ¤ç å¸ ;æ (b)ç¡®ç« å »ç å ³ç³»ç å ¦ä¸ å å »ç ã é ç ¨å 容å æ æ³ å¯¹æ °æ ®è¿ è¡ å æ ã ç» æ æ 们é è®¿äº 28å æ £è ,17å å »ç å 14å æ ¤ç å¸ ã æ 们å ç °:(a)æ ¤ç å¸ æ¯ å »ç æ ä¾ ç æ ¤ç æ ´å ¨é ¢;(b)æ £è å¯¹æ ¤ç å¸ æ å °æ»¡æ ;(c)å »ç æ ºæ ç ä¸ ä¸ ç» éª ç æ é æ¯ å »ç æ ºæ ç±»å ç æ é æ ´å¤§ã ç» è®ºæ £è å¯¹æ ¤ç å¸ ç å 好(ä¸ ä»¥å ç å »ç ç ¸æ¯ )æ å ©äº å»ºç« ä»¥æ £è 为ä¸å¿ ç è®¤ç ¥ã æ ä¾ è ç è§ å¿µç±»ä¼¼,表æ æ ¤ç å¸ å å »ç é ½æ ¯å ¯è¡ ç å çº§æ ¤ç æ ä¾ è ã å½±å - ¢æ ¤ç å¸ :æ §ä¸ æ ºæ - ¢é ä¼ å äººå »ç ä¿ å ¥ç³»ç» :æ ¤ç å¸ å° ç»§ç»ä½ 为æ ä¾ å çº§æ ¤ç æ å ¡ç å ¯ç ¨èµ æº ã - ¢ç¾ å ½å «ç ä¿ å ¥:æ æ è§ å¿µ
æ £è å ¯è ½ä¸ æ»¡æ ç ±æ ¤ç å¸ æ ä¾ ç æ ¤ç ,å ¶ä¼ æ ¯æ æ ©å¤§ä½¿ç ¨è å ´,以æ ä¾ æ ¥é ç å çº§ä¿ å ¥æ å ¡;æ ©å¤§å ¨ç§ æ §ä¸ æ ºæ å° ä½¿å å· è ½å¤ æ ä¾ å ¯æ ¥å ç å çº§ä¿ å ¥æ å ¡,è ä¸ ä¼ å å¼±æ £è æ æ ä¾ è ç ä½ éª ãPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/163369/2/jan14501.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163369/1/jan14501_am.pd
A Comparison of Maps and Power Spectra Determined from South Pole Telescope and Planck Data
We study the consistency of 150 GHz data from the South Pole Telescope (SPT)
and 143 GHz data from the Planck satellite over the patch of sky covered by the
SPT-SZ survey. We first visually compare the maps and find that the residuals
appear consistent with noise after accounting for differences in angular
resolution and filtering. We then calculate (1) the cross-spectrum between two
independent halves of SPT data, (2) the cross-spectrum between two independent
halves of Planck data, and (3) the cross-spectrum between SPT and Planck data.
We find the three cross-spectra are well-fit (PTE = 0.30) by the null
hypothesis in which both experiments have measured the same sky map up to a
single free calibration parameter---i.e., we find no evidence for systematic
errors in either data set. As a by-product, we improve the precision of the SPT
calibration by nearly an order of magnitude, from 2.6% to 0.3% in power.
Finally, we compare all three cross-spectra to the full-sky Planck power
spectrum and find marginal evidence for differences between the power spectra
from the SPT-SZ footprint and the full sky. We model these differences as a
power law in spherical harmonic multipole number. The best-fit value of this
tilt is consistent among the three cross-spectra in the SPT-SZ footprint,
implying that the source of this tilt is a sample variance fluctuation in the
SPT-SZ region relative to the full sky. The consistency of cosmological
parameters derived from these datasets is discussed in a companion paper.Comment: 15 pages, 9 figures. Published in The Astrophysical Journal. Current
arxiv version matches published versio
A Measurement of the Cosmic Microwave Background Damping Tail from the 2500-square-degree SPT-SZ survey
We present a measurement of the cosmic microwave background (CMB) temperature
power spectrum using data from the recently completed South Pole Telescope
Sunyaev-Zel'dovich (SPT-SZ) survey. This measurement is made from observations
of 2540 deg of sky with arcminute resolution at GHz, and improves
upon previous measurements using the SPT by tripling the sky area. We report
CMB temperature anisotropy power over the multipole range . We
fit the SPT bandpowers, combined with the seven-year Wilkinson Microwave
Anisotropy Probe (WMAP7) data, with a six-parameter LCDM cosmological model and
find that the two datasets are consistent and well fit by the model. Adding SPT
measurements significantly improves LCDM parameter constraints; in particular,
the constraint on tightens by a factor of 2.7. The impact of
gravitational lensing is detected at , the most significant
detection to date. This sensitivity of the SPT+WMAP7 data to lensing by
large-scale structure at low redshifts allows us to constrain the mean
curvature of the observable universe with CMB data alone to be
. Using the SPT+WMAP7 data, we measure the
spectral index of scalar fluctuations to be in the LCDM
model, a preference for a scale-dependent spectrum with .
The SPT measurement of the CMB damping tail helps break the degeneracy that
exists between the tensor-to-scalar ratio and in large-scale CMB
measurements, leading to an upper limit of (95%,C.L.) in the LCDM+
model. Adding low-redshift measurements of the Hubble constant () and the
baryon acoustic oscillation (BAO) feature to the SPT+WMAP7 data leads to
further improvements. The combination of SPT+WMAP7++BAO constrains
in the LCDM model, a detection of , ... [abridged]Comment: 21 pages, 10 figures. Replaced with version accepted by ApJ. Data
products are available at http://pole.uchicago.edu/public/data/story12
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