96 research outputs found
Sum rules for light-by-light scattering
We derive a set of sum rules for the light-by-light scattering and fusion:
, and verify them in lowest order QED calculations. A
prominent implication of these sum rules is the superconvergence of the
helicity-difference total cross-section for photon fusion, which in the hadron
sector reveals an intricate cancellation between the pseudoscalar and tensor
mesons. An experimental verification of superconvergence of the polarized
photon fusion into hadrons is called for, but will only be possible at and colliders with both beams polarized. We also show how
the sum rules can be used to measure various contributions to the low-energy
light-by-light scattering.Comment: 4 pages, 3 figures; minor corrections, published versio
Is the Library Ready for an Emerging Field? The Case of Veterans Studies
How can libraries and archives prepare for emerging scholarly fields that have not yet emerged? How do we know when such a “discipline” is emerging, and how might we support it?
An archivist at Special Collections and the history/social science librarian at the Virginia Tech Libraries saw signs of research interest about veterans on their campus and elsewhere. With an interest in supporting what might be considered an emerging field, both were aware of the risks of investing in materials that do not attract users. This presentation will examine their process of evaluating those risks while assessing evidence of a growing need. After a review of existing holdings, they began to survey the research landscape for indications of the subjects, disciplines, methods, and constituencies that might consolidate as a discrete field of veterans studies. Further, given the absence of indicators that mark established fields—regular conferences, journals, academic programs—they turned towards a strategy of actively “seeding the need” by engaging in interdisciplinary conversations on the matter of veterans studies and gauging reaction and participation. As a consequence of this work, both librarian and archivist have become active in projects that are creating the very indicators that suggest veterans studies may emerge as a field of academic inquiry requiring library support. At this session, this process and its results to date will be discussed, along with the project\u27s implications for special and circulating collections and, more broadly, the library\u27s scholarly communications initiatives
Light-by-light scattering sum rules constraining meson transition form factors
Relating the forward light-by-light scattering to energy weighted integrals
of the \gamma* \gamma -fusion cross sections, with one real photon (\gamma) and
one virtual photon (\gamma*), we find two new exact super-convergence
relations. They complement the known super-convergence relation based on the
extension of the GDH sum rule to the light-light system. We also find a set of
sum rules for the low-energy photon-photon interaction. All of the new
relations are verified here exactly at leading order in scalar and spinor QED.
The super-convergence relations, applied to the \gamma* \gamma -production of
mesons, lead to intricate relations between the \gamma \gamma -decay widths or
the \gamma* \gamma -transition form factors for (pseudo-) scalar, axial-vector
and tensor mesons. We discuss the phenomenological implications of these
results for mesons in both the light-quark sector and the charm-quark sector.Comment: 32 pages, 7 figure
Special Collections - Challenges and Contexts: A Case Study
Special collections are undergoing a period of rapid change, as are the libraries of which they are often a part. The Association of Research Libraries (ARL) decided in the late 1990s to study special collections at member institutions in light of changing demands and expectations from users, new technologies, and changing fiscal realities. The purpose of this study is to offer an overview of the challenges facing special collections as presented by the ARL and to determine whether these challenges are also being experienced at smaller institutions that are not affiliated with a research library. To this end, the paper will present a case study of Special Collections at the University of North Carolina, Asheville (UNCA)
Core Competencies for Integrative Medicine Fellowship Training Programs
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140347/1/acm.2014.5258.abstract.pd
Comparison of total ankle replacement and ankle arthrodesis in patients with haemophilia using gait analysis : two case reports
BACKGROUND: Severe hemophilia is an inherited, lifelong bleeding disorder characterized by spontaneous bleeding, which results in painful joint deformities. Currently two surgical treatments are available to treat haemophilia-related ankle joint destruction: ankle arthrodesis and total ankle replacement. The aim of the present study was to compare these two surgical procedures in haemophiliac subjects. CASE PRESENTATION: Kinematic and dynamic parameters were quantified using a three-dimensional gait-analysis system in two similar clinical cases. In Caucasian case 1, ankle arthrodesis was chosen because of a kinematic ankle flexion defect and lack of dynamic power regeneration. The defect in energy absorption was compensated for by the contralateral side. Total ankle replacement in Caucasian case 2 allowed sparing the ipsilateral knee (maximum 0.27 preoperatively vs. 0.71 W/kg postoperatively) and hip joints powers (maximum 0.43 preoperatively vs. 1.25 W/kg postoperatively) because of the small ankle dorsiflexion motion. CONCLUSIONS: Total ankle replacement is recommended for haemophiliac patients who present with a preserved ankle range of motion
Scleroderma, Stress and CAM Utilization
Scleroderma is an autoimmune disease influenced by interplay among genetic and environmental factors, of which one is stress. Complementary and alternative medicine (CAM) is frequently used to treat stress and those diseases in which stress has been implicated. Results are presented from a survey of patients with scleroderma. Respondents were a convenient sample of those attending a national conference in Las Vegas in 2002. Findings implicate stress in the onset, continuation and exacerbation of scleroderma. The implication is that CAM providers may be filling an important patient need in their provision of services that identify and treat stress and its related disorders
Final state interactions and the transverse structure of the pion using non-perturbative eikonal methods
In the factorized picture of semi-inclusive hadronic processes the naive time
reversal-odd parton distributions exist by virtue of the gauge link which
renders it color gauge invariant. The link characterizes the dynamical effect
of initial/final-state interactions of the active parton due soft gluon
exchanges with the target remnant. Though these interactions are
non-perturbative, studies of final-state interaction have been approximated by
perturbative one-gluon approximation in Abelian models. We include higher-order
contributions by applying non-perturbative eikonal methods incorporating color
degrees of freedom in a calculation of the Boer-Mulders function of the pion.
Using this framework we explore under what conditions the Boer Mulders function
can be described in terms of factorization of final state interactions and a
spatial distribution in impact parameter space.Comment: To appear in Phys.Lett.B, 9 pages, 5 figures, added refs. and
discussio
Antimyeloma Effects of the Heat Shock Protein 70 Molecular Chaperone Inhibitor MAL3-101
Multiple myeloma
(MM) is the second most common hematologic
malignancy and remains incurable, primarily due
to the treatment-refractory/resistant nature of
the disease. A rational approach to this
compelling challenge is to develop new drugs
that act synergistically with existing effective
agents. This approach will reduce drug
concentrations, avoid treatment resistance, and
also improve treatment effectiveness by
targeting new and nonredundant pathways in MM.
Toward this goal, we examined the antimyeloma
effects of MAL3-101, a member of a new class of
non-ATP-site inhibitors of the heat shock
protein (Hsp) 70 molecular chaperone. We
discovered that MAL3-101 exhibited antimyeloma
effects on MM cell lines in
vitro and in vivo in a
xenograft plasmacytoma model, as well as on
primary tumor cells and bone marrow endothelial
cells from myeloma patients. In combination with
a proteasome inhibitor, MAL3-101 significantly
potentiated the in vitro and
in vivo antimyeloma effects.
These data support a preclinical rationale for
small molecule inhibition of Hsp70 function,
either alone or in combination with other
agents, as an effective therapeutic strategy for
MM
New Bounds on R-parity Violating Couplings
We use information from rare nonleptonic decays of heavy-quark mesons to put
new bounds on the magnitudes of certain product combinations of baryon
nonconserving R-parity violating couplings in supersymmetric models. Product
combinations of lepton and baryon nonconserving R-parity violating couplings
are also considered in the light of existing bounds on nucleon decay. Contrary
to popular impression, a few such combinations are shown to remain essentially
unconstrained.Comment: Latex file, 16 pages including 6 uuencoded Postscript files appended.
Figures also available via anonymous ftp at ftp://physics.wm.edu/pub/ (get
rparity*.ps). Revised version corrects a few sentences in introduction and
adds some reference
- …