1,263 research outputs found
Centrally extended symmetry algebra of asymptotically Goedel spacetimes
We define an asymptotic symmetry algebra for three-dimensional Goedel
spacetimes supported by a gauge field which turns out to be the semi-direct sum
of the diffeomorphisms on the circle with two loop algebras. A class of fields
admitting this asymptotic symmetry algebra and leading to well-defined
conserved charges is found. The covariant Poisson bracket of the conserved
charges is then shown to be centrally extended to the semi-direct sum of a
Virasoro algebra and two affine algebras.Comment: 12 pages, sign mistake corrected in the central charge, takes
precedence over published versio
Investigating the Role of LIN-35 and the DREAM Complex in Preserving Fertility Under Stress in C. elegans
Organisms are subjected to environments that can fluctuate and cause them stress. Therefore, organisms must have the ability to adapt to the stress to survive and propagate. Temperature stress is becoming an increasingly relevant type of stress due to climate change and is known to affect fertility in many types of organisms including the model organism Caenorhabditis elegans. Here we examine the role of LIN-35, the single C. elegans homolog of the tumor suppressor Retinoblastoma (pRB), in fertility under moderate temperature stress. We found that lin-35 mutants lose fertility more drastically under moderate temperature stress than wildtype worms, and that this loss of fertility is dependent on both somatic and germline expression of LIN-35. A common cellular response to stress is programmed cell death via apoptosis. In C. elegans, the only adult tissue that exhibits apoptosis is the germline and while germline apoptosis eliminates ~50% of all oogenic germ cell nuclei during normal oogenesis, the induction of higher levels of germline apoptosis appears to be a general response to stressful conditions. LIN-35 was previously shown to be important for germline apoptosis but because it cannot bind to DNA by itself it must work with other partners to regulate genes. A group of proteins LIN-35 works with in some contexts is the DREAM complex, a conserved multi-subunit transcriptional repressor complex. We found that there is an induction of germline apoptosis under moderate temperature stress and that LIN-35 and the DREAM complex are important for this induction. The DREAM complex and LIN-35 are also important for DNA damage induced apoptosis. Together this indicates a general role for LIN-35 and the DREAM complex in the induction of germline apoptosis in response to stress. This role in germline apoptosis may be the role in the germline that LIN-35 has that helps it to preserve fertility
Kerr/CFT Correspondence in the Low Energy Limit of Heterotic String Theory
We investigate the recently proposed Kerr/CFT correspondence in the context
of heterotic string theory. The Kerr/CFT correspondence states that the
near-horizon states of an extremal four (or higher) dimensional black hole
could be identified with a certain chiral conformal field theory under the
conjecture that the central charges from the non-gravitational fields vanish.
The corresponding Virasoro algebra is generated by a class of diffeomorphisms
which preserves the appropriate boundary conditions on the near-horizon
geometry. To understand the chiral conformal field theory, we consider the
class of extremal Kerr-Sen black hole (that contains three non-gravitational
fields) as a class of solutions in the low energy limit (effective field
theory) of heterotic string theory. We derive the expression of the conserved
charges for the extremal Kerr-Sen solutions that contain dilaton, abelian gauge
filed and antisymmetric tensor filed. We confirm and extend the validity of the
conjecture (that the central charges from the non-gravitational fields vanish)
for theories including antisymmetric tensor fields. We combine the calculated
central charges with the expected form of the temperature using the Cardy
formula to obtain the entropy of the extremal black hole microscopically; in
agreement with the macroscopic Bekenstein-Hawking entropy of the extremal black
hole.Comment: 14 pages, a few sentences added to the introduction, version to
appear in JHE
The Relationships Between Nursing Staff Knowledge of Personhood and Resident Cognitive Status
The purpose of this pilot study was to explore the relationships between nursing staff knowledge of extended care resident personhood and resident cognitive status. Eighty nursing staff from two similar extended care facilities in Arkansas completed a self-administered questionnaire to assess their knowledge of 21 residents, including information related to residents’ past jobs/careers; likes/dislikes/ interests; family members; other non-specific knowledge; and total knowledge. The Brief Interview for Mental Status (BIMS) was used to evaluate resident cognitive impairment. Results of a Pearson correlation demonstrate a positive correlation between (1) staff knowledge of residents’ families, and (2) total knowledge of residents with resident cognitive status. Findings suggest that nursing staff utilize creative interventions and exert intentional efforts to obtain resident information to preserve personhood and provide PCDC
The Relationships Between Nursing Staff Knowledge of Personhood and Resident Cognitive Status
The purpose of this pilot study was to explore the relationships between nursing staff knowledge of extended care resident personhood and resident cognitive status. Eighty nursing staff from two similar extended care facilities in Arkansas completed a self-administered questionnaire to assess their knowledge of 21 residents, including information related to residents’ past jobs/careers; likes/dislikes/ interests; family members; other non-specific knowledge; and total knowledge. The Brief Interview for Mental Status (BIMS) was used to evaluate resident cognitive impairment. Results of a Pearson correlation demonstrate a positive correlation between (1) staff knowledge of residents’ families, and (2) total knowledge of residents with resident cognitive status. Findings suggest that nursing staff utilize creative interventions and exert intentional efforts to obtain resident information to preserve personhood and provide PCDC
Cargese Lectures on the Kerr/CFT Correspondence
We give a short introduction, beginning with the Kerr geometry itself, to the
basic results, motivation, open problems and future directions of the Kerr/CFT
correspondence.Comment: Lectures given by A. Strominger at Cargese 2010. References update
Hidden Conformal Symmetry of Warped AdS_3 Black Holes
We show that for a certain low frequency limit the wave equation of a generic
massive scalar field in the background of the spacelike warped AdS_3 black hole
can be written as the Casimir of an SL(2,R) symmetry. Two sets of SL(2,R)
generators are found which uncover the hidden SL(2,R)\times SL(2,R) symmetry of
the solution. This symmetry is only locally defined and is spontaneously broken
to U(1)\times U(1) by a periodic identification of the \phi coordinate. By
using the generator of the identification we read the left and right
temperatures (T_L,T_R) of the proposed dual conformal field theory which are in
complete agreement with the WAdS/CFT conjecture. Moreover, under the above
condition of the scalar wave frequency, absorption cross section of the scalar
field is consistent with the two-point function of the dual CFT.Comment: 12 pages; V2: references added, minor correction; V3: published
version, minor clarification in section 3, typos corrected, one reference
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