1,657 research outputs found
Slavery and sectionalism: some aspects of church and society among Presbyterians in the American south, 1789 - 1861
Photon Structure and Quantum Fluctuation
Photon structure derives from quantum fluctuation in quantum field theory to
fermion and anti-fermion, and has been an experimentally established feature of
electrodynamics since the discovery of the positron. In hadronic physics, the
observation of factorisable photon structure is similarly a fundamental test of
the quantum field theory Quantum Chromodynamics (QCD). An overview of
measurements of hadronic photon structure in e+e- and ep interactions is
presented, and comparison made with theoretical expectation, drawing on the
essential features of photon fluctuation into quark and anti-quark in QCD.Comment: 29 pages, 15 figures, to appear in Philosophical Transactions of the
Royal Society of London (Series A: Mathematical, Physical and Engineering
Sciences
Ductless Mini-Split Heat Pump Comfort Evaluation
Field tests were conducted in two homes in Austin, TX to evaluate the comfort performance of ductless mini-split heat pumps (DMSHPs), measuring temperature and relative humidity measurements in four rooms in each home before and after retrofitting a central HVAC system with DMSHPs
Journal- Based Reflection in Undergraduate Service Learning and the University Therapeutic Riding Center
Principles of Therapeutic Riding, Animal Science 3309, is a service- based learning course that gives undergraduates the opportunity to participate in hippotherapy sessions. This course first offered in 1998, has been held for 12 semesters. A total of 233 students from over 15 majors have been trained in this discipline. Advanced Therapeutic Riding, Animal Science 4001, is a continuation of the Principles class that allows students to participate in the sessions and serve in leadership roles. This class has been active for 8 semesters and has included 51 students
Photolytic modification of seasonal nitrate isotope cycles in East Antarctica
Nitrate in Antarctic snow has seasonal cycles in nitrogen and oxygen isotopic ratios that reflect its sources and atmospheric formation processes,
and as a result, nitrate archived in Antarctic ice should have great potential to record atmospheric chemistry changes over thousands of
years. However, sunlight that strikes the snow surface results in photolytic nitrate loss and isotopic fractionation that can completely obscure the
nitrate's original isotopic values. To gain insight into how photolysis overwrites the seasonal atmospheric cycles, we collected 244Â snow samples
along an 850 km transect of East Antarctica during the 2013–2014 CHICTABA traverse. The CHICTABA route's limited elevation change, consistent
distance between the coast and the high interior plateau, and intermediate accumulation rates offered a gentle environmental gradient ideal for
studying the competing pre- and post-depositional influences on archived nitrate isotopes. We find that nitrate isotopes in snow along the transect
are indeed notably modified by photolysis after deposition, and drier sites have more intense photolytic impacts. Still, an imprint of the original
seasonal cycles of atmospheric nitrate isotopes is present in the top 1–2 m of the snowpack and likely preserved through archiving in
glacial ice at these sites. Despite this preservation, reconstructing past atmospheric values from archived nitrate in similar transitional regions
will remain a difficult challenge without having an independent proxy for photolytic loss to correct for post-depositional isotopic
changes. Nevertheless, nitrate isotopes should function as a proxy for snow accumulation rate in such regions if multiple years of deposition are
aggregated to remove the seasonal cycles, and this application can prove highly valuable in its own right.</p
Model independent results for and at order
Exclusive semileptonic B decays into and mesons are
investigated including order corrections using the
heavy quark effective theory. At zero recoil, the
corrections can be written in terms of the leading Isgur-Wise function for
these transitions, , and known meson mass splittings. We obtain an almost
model independent prediction for the shape of the spectrum near zero recoil,
including order corrections. We determine
from the measured branching ratio. Implications for B
decay sum rules are discussed.Comment: 11 pages, revte
Multimodal sentinel lymph node mapping with single-photon emission computed tomography (SPECT)/computed tomography (CT) and photoacoustic tomography
The identification of cancer cells in the lymph nodes surrounding a tumor is important in establishing a prognosis. Optical detection techniques such as fluorescence and photoacoustic tomography (PAT) have been reported in preclinical studies for noninvasive sentinel lymph node (SLN) mapping. A method for validation of these techniques is needed for clinical trials. We report the use of a multimodal optical-radionuclear contrast agent as a validation tool for PAT in a preclinical model. Methylene blue (MB) was radiolabeled with ^(125)I for multimodal SLN mapping and used in conjunction with MB to assess the feasibility of multimodal SLN mapping in a rat model by PAT and single-photon emission computed tomography (SPECT). MB provided sufficient contrast for identifying SLNs noninvasively with a PAT system adapted from a clinical ultrasound imaging system. The signal location was corroborated by SPECT using ^(125)I labeled MB. The translation of PAT into the clinic can be facilitated by a direct comparison with established imaging methods using a clinically relevant dual SPECT and photoacoustic imaging agent. The new high-resolution PAT is a promising technology for the sensitive and accurate SLN detection in cancer patients
Phenomenological Study of Strong Decays of Heavy Hadrons in Heavy Quark Effective Theory
The application of the tensor formalism of the heavy quark effective theory
(HQET) at leading order to strong decays of heavy hadrons is presented.
Comparisons between experimental and theoretical predictions of ratios of decay
rates for B mesons, D mesons and kaons are given. The application of HQET to
strange mesons presents some encouraging results. The spin-flavor symmetry is
used to predict some decay rates that have not yet been measured.Comment: 10 page
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