8,714 research outputs found
Matrix Description of Interacting Theories in Six Dimensions
We propose descriptions of interacting (2,0) supersymmetric theories without
gravity in six dimensions in the infinite momentum frame. They are based on the
large limit of quantum mechanics or 1+1 dimensional field theories on the
moduli space of instantons in \IR^4.Comment: 10 pages, harvmac bi
The Scaling of the No Scale Potential and de Sitter Model Building
We propose a variant of the KKLT (A)dS flux vacuum construction which does
not require an antibrane to source the volume modulus. The strategy is to find
nonzero local minima of the no-scale potential in the complex structure and
dilaton directions in moduli space. The corresponding no-scale potential
expanded about this point sources the volume modulus in the same way as does
the antibrane of the KKLT construction. We exhibit explicit examples of such
nonzero local minima of the no-scale potential in a simple toroidal orientifold
model.Comment: 11 pages, harvmac big. v2: trivial typos fixe
Introduction and Expression of a Rabbit ÎČ-globin Gene in Mouse Fibroblasts
The cloned chromosomal rabbit Ă-globin gene has been introduced into mouse fibroblasts by DNA-mediated gene transfer (transformation). In this report, we examine the expression of the rabbit gene in six independent transformants that contain from 1 to 20 copies of the cloned globin gene. Rabbit globin transcripts were detected in two of these transformants at steady-state concentrations of 5 and 2 copies per cell. The globin transcripts from one cell line are polyadenylylated and migrate as 9S RNA on methylmercury gels. These transcripts reflect correct processing of the two intervening sequences but lack 48 ± 5 nucleotides present at the 5' terminus of rabbit erythrocyte globin mRNA
Chronic Disease Self-Management Programs: Relevance for Persons with Dementia
The context for this study is the work of the Healthy Brain Initiative. The CDC has established a cooperative agreement with the Alzheimerâs Association to develop and implement a multifaceted approach to look at cognitive health as a public health issue. Late in 2010, the Association commissioned a review of the major chronic disease prevention programs from a systems approach to begin to understand the source of findings that Medicare beneficiaries with Alzheimerâs and related disorders are much higher cost than those simply with a single chronic disease and no AD. This led to the conclusion that Chronic Disease SelfâManagement Program (CDSMP) is the current âgold standardâ initiative in this arena. Thus, the Association in cooperation with Dr. Kate Lorig, the researcher who developed CDSMP, began systematic research to explore the extent to which persons with AD are served in CDSMP workshops. Dr. Lorig is the Director of the Stanford Patient Education Research Center and Professor of Medicine in the Stanford School of Medicine
âGrowing Pains and Challengesâ: GrandFamilies House Four-Year Follow-Up Evaluation
During the past decade, there has been increased awareness of issues facing grandparent caregiver families on the part of policymakers and service providers. This awareness has prompted efforts to document the numbers of children being raised by grandparents, to identify challenges faced by grandparents raising grandchildren, and to provide services to meet the needs of these families. National estimates suggest that the numbers of grandparent caregiver families are increasing. Recent estimates suggest that 1.4 million (2%) of all children under 18 live in âskipped generationâ families in the United States; similarly, 29,000 (nearly 2%) of all children in Massachusetts live in grandparent care. A large majority of grandparent caregivers are responsible for grandchildren three years or more, suggesting that this is a sustained commitment.
Grandparent caregiving is a social phenomenon that cuts across all socioeconomic, racial, and ethnic groups. However, a substantial number of grandparent caregiver families face economic hardship; in Massachusetts, a third of grandparent caregiving families and half the grandchildren in grandparent care families have incomes below 133% the federal poverty index. These nontraditional families face many challenges, including healthcare, income security, education, social support, and housing. Public and private partnerships are beginning to respond to some of these challenges. An initiative to provide affordable, supportive housing for grandparent caregiver families was undertaken in 1998. The current report, based on the first four years of the initiative, builds on an earlier study based on the initial six months. It presents the experiences and views of families and front-line staff, as well as reflections from those responsible for its development. Recommendations are presented for future efforts to address supportive housing for grandparent caregiver families
Towards a holographic marginal Fermi liquid
We present an infinite class of 2+1 dimensional field theories which, after
coupling to semi-holographic fermions, exhibit strange metallic behavior in a
suitable large limit. These theories describe lattices of hypermultiplet
defects interacting with parity-preserving supersymmetric Chern-Simons theories
with gauge groups at levels . They have dual
gravitational descriptions in terms of lattices of probe M2 branes in (for ) or probe D2 branes in (for ). We discuss several challenges one faces
in maintaining the success of these models at finite , including
backreaction of the probes in the gravity solutions and radiative corrections
in the weakly coupled field theory limit.Comment: 9 pages, RevTeX; v2, minor correction
Unitarity bounds and RG flows in time dependent quantum field theory
We generalize unitarity bounds on operator dimensions in conformal field
theory to field theories with spacetime dependent couplings. Below the energy
scale of spacetime variation of the couplings, their evolution can strongly
affect the physics, effectively shifting the infrared operator scaling and
unitarity bounds determined from correlation functions in the theory. We
analyze this explicitly for large- double-trace flows, and connect these to
UV complete field theories. One motivating class of examples comes from our
previous work on FRW holography, where this effect explains the range of
flavors allowed in the dual, time dependent, field theory.Comment: 38 page
A New Handle on de Sitter Compactifications
We construct a large new class of de Sitter (and anti de Sitter) vacua of
critical string theory from flux compactifications on products of Riemann
surfaces. In the construction, the leading effects stabilizing the moduli are
perturbative. We show that these effects self-consistently dominate over
standard estimates for further and quantum corrections, via
tuning available from large flux and brane quantum numbers.Comment: 26 pages, harvmac big. v2: Correction generalizing specific
ingredients required for tunable negative term; conclusions and structure of
potential unchange
4d Conformal Field Theories and Strings on Orbifolds
We propose correspondences between 4d quantum field theories with N=2,1,0
(super)conformal invariance and Type IIB string theory on various orbifolds. We
argue using the spacetime string theory, and check using the beta functions
(exactly for N=2,1 and so far at 1-loop for the gauge couplings in the N=0
case), that these theories have conformal fixed lines. The latter case
potentially gives well-defined non-supersymmetric vacua of string theory, with
a mechanism for making the curvature and cosmological constant small at
nontrivial string coupling. We suggest a correspondence between
nonsupersymmetric conformal fixed lines and nonsupersymmetric string vacua with
vanishing vacuum energy.Comment: 11 pages, harvmac big. Reference adde
Study of resonance light scattering for remote optical probing
Enhanced scattering and fluorescence processes in the visible and UV were investigated which will enable improved remote measurements of gas properties. The theoretical relationship between scattering and fluorescence from an isolated molecule in the approach to resonance is examined through analysis of the time dependence of re-emitted light following excitation of pulsed incident light. Quantitative estimates are developed for the relative and absolute intensities of fluorescence and resonance scattering. New results are obtained for depolarization of scattering excited by light at wavelengths within a dissociative continuum. The experimental work was performed in two separate facilities. One of these utilizes argon and krypton lasers, single moded by a tilted etalon, and a 3/4 meter double monochromator. This facility was used to determine properties of the re-emission from NO2, I2 and O3 excited by visible light. The second facility involves a narrow-line dye laser, and a 3/4 meter single monochromator. The dye laser produces pulsed light with 5 nsec pulse duration and 0.005 nm spectral width
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