7,457 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
Introduction and Expression of a Rabbit β-globin Gene in Mouse Fibroblasts
The cloned chromosomal rabbit ß-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
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
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
On the Matrix Description of Calabi-Yau Compactifications
We point out that the matrix description of M-theory compactified on
Calabi-Yau threefolds is in many respects simpler than the matrix description
of a compactification. This is largely because of the differences between
D6 branes wrapped on Calabi-Yau threefolds and D6 branes wrapped on six-tori.
In particular, if we define the matrix theory following the prescription of Sen
and Seiberg, we find that the remaining degrees of freedom are decoupled from
gravity.Comment: 12 pages, harvmac big; comment on 4d N=1 theories change
Living with Alzheimer’s Disease: A Study of Adult Day Health Services in Massachusetts
The role of adult day health care (ADHC) is gaining increased attention as the nation prepares for the large cohort of baby boomers entering their later years. Many boomers are aging with physical and cognitive impairments, including Alzheimer\u27s disease and related dementias. Projections indicate that Massachusetts, along with the nation as a whole, is experiencing an increasing rate of older persons as baby boomers enter late-life. The Commonwealth can expect that persons with Alzheimer\u27s disease and their care partners will need community-based services that are specifically designed for adults with cognitive impairments. However, a report by the Robert Wood Johnson Foundation found that there is a serious lack of adult day care services for the state\u27s elderly population. The 2003 report found that Massachusetts is only meeting 62% of needs for adults with physical and cognitive impairments, and at least 78 more programs are needed in the state. Yet, programs in Massachusetts continue to close.
The specific objectives of the study were to: (1) describe existing practices of adult day health care services in Massachusetts for persons living with Alzheimer\u27s disease and related dementias, (2) explore programs that are specifically designed for participants who are in late-stage dementia, (3) address challenges that adult day health care services are now encountering, and (4) envision new paradigms for meeting the needs of persons with early-stage and early-onset dementia
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
Stable de Sitter vacua in N=2, D=5 supergravity
We find 5D gauged supergravity theories exhibiting stable de Sitter vacua.
These are the first examples of stable de Sitter vacua in higher-dimensional
(D>4) supergravity. Non-compact gaugings with tensor multiplets and R-symmetry
gauging seem to be the essential ingredients in these models. They are however
not sufficient to guarantee stable de Sitter vacua, as we show by investigating
several other models. The qualitative behaviour of the potential also seems to
depend crucially on the geometry of the scalar manifold.Comment: 26 pages, v2:typos corrected, published versio
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