2,821 research outputs found
Structure Thermolysis Relationships for Energetic Materials
The technique of fast thermolysis/FTIR spectroscopy, in which temperature profiling of the condensed phase is also conducted, is described. Applications are given to show how the formation of NO2, HONO, NO, and CH2O can be related to underlying parent molecular features. The effect of pressure in the 1-1000 psi range on the overall process is presented along with an example of how pressure can be used to distinguish the gas phase reactions from the condensed phase reactions during fast thermolysis
Arrival At the Same Point: My Long, Winding, and Not-So-Circular Path to Professor
This is my story of the constant struggle between wanting both mathematics and motherhood, and realizing I could have it all but not all at once.The story involves earning degrees, securing a tenure-track position only to resign two years later, and then, through a gauntlet of adjunct and fixed-term positions, applying for and accepting another tenure-track position at the same institution, finally arriving back at the same point on the path I had been on sixteen years earlier. I walked this long, winding, and ultimately no-so-circular path while becoming and being a mother of four. It is my hope that this story inspires other mathematicians and mothers to carve their own path, and to know it does not have to look like the path most others have walked; it just has to be a path that works for them
Replication factor-A from Saccharomyces cerevisiae is encoded by three essential genes coordinately expressed at S phase
Replication factor-A (RF-A) is a three-subunit protein complex originally purified from human cells as an essential component for SV40 DNA replication in vitro. We have previously identified a functionally homologous three-subunit protein complex from the yeast Saccharomyces cerevisiae. Here we report the cloning and characterization of the genes encoding RF-A from S. cerevisiae. Each of the three subunits is encoded by a single essential gene. Cells carrying null mutations in any of the three genes arrest as budded and multiply budded cells. All three genes are expressed in a cell-cycle-dependent manner; the mRNA for each subunit peaks at the G1/S-phase boundary. A comparison of protein sequences indicates that the human p34 subunit is 29% identical to the corresponding RFA2 gene product. However, expression of the human protein fails to rescue the rfa2::TRP1 disruption
Investigating Peer Review as an Intentional Learning Strategy to Foster Collaborative Knowledge-Building in Students of Instructional Design
Peer review has been advocated for as an intentional strategy to support the knowledge and skill attainment of adult learners preparing for professional practice, including those students preparing for instructional design and technology practice. The purposes of this article are to discuss the practical application of peer review as an instructional strategy by articulating its use in both face-to-face and online Instructional Design courses and to formulate directions for future research on the use of peer review in instructional practice. Findings from a literature review of student-to-student peer review and the authors\u27 experiences with the use of peer review in Instructional Design courses are used to foster a discussion that interweaves both important scholarly and practical elements
Interacting scalar and spinor fields in Bianchi type I universe filled with magneto-fluid
Self-consistent system of spinor, scalar and BI gravitational fields in
presence of magneto-fluid and -term is considered. Assuming that the
expansion of the BI universe is proportional to the component of
the shear tensor, exact solutions for the metric functions, as well as for
scalar and spinor fields are obtained. For a non-positive the
initially anisotropic space-time becomes isotropic one in the process of
expansion, whereas, for an oscillatory mode of expansion of the
BI model occurs.Comment: RevTex4, 8 pages, no figure
Curvature tensors on distorted Killing horizons and their algebraic classification
We consider generic static spacetimes with Killing horizons and study
properties of curvature tensors in the horizon limit. It is determined that the
Weyl, Ricci, Riemann and Einstein tensors are algebraically special and
mutually aligned on the horizon. It is also pointed out that results obtained
in the tetrad adjusted to a static observer in general differ from those
obtained in a free-falling frame. This is connected to the fact that a static
observer becomes null on the horizon.
It is also shown that finiteness of the Kretschmann scalar on the horizon is
compatible with the divergence of the Weyl component or
in the freely falling frame. Furthermore finiteness of is compatible
with divergence of curvature invariants constructed from second derivatives of
the Riemann tensor.
We call the objects with finite Krestschmann scalar but infinite
``truly naked black holes''. In the (ultra)extremal versions of these objects
the structure of the Einstein tensor on the horizon changes due to extra terms
as compared to the usual horizons, the null energy condition being violated at
some portions of the horizon surface. The demand to rule out such divergencies
leads to the constancy of the factor that governs the leading term in the
asymptotics of the lapse function and in this sense represents a formal analog
of the zeroth law of mechanics of non-extremal black holes. In doing so, all
extra terms in the Einstein tensor automatically vanish.Comment: 21 pages, To appear in Class. Quant. Gra
Black Hole Thermodynamics and Riemann Surfaces
We use the analytic continuation procedure proposed in our earlier works to
study the thermodynamics of black holes in 2+1 dimensions. A general black hole
in 2+1 dimensions has g handles hidden behind h horizons. The result of the
analytic continuation is a hyperbolic 3-manifold having the topology of a
handlebody. The boundary of this handlebody is a compact Riemann surface of
genus G=2g+h-1. Conformal moduli of this surface encode in a simple way the
physical characteristics of the black hole. The moduli space of black holes of
a given type (g,h) is then the Schottky space at genus G. The (logarithm of
the) thermodynamic partition function of the hole is the Kaehler potential for
the Weil-Peterson metric on the Schottky space. Bekenstein bound on the black
hole entropy leads us to conjecture a new strong bound on this Kaehler
potential.Comment: 17+1 pages, 9 figure
Quantum Creation of Topological Black Hole
The constrained instanton method is used to study quantum creation of a
vacuum or charged topological black hole. At the level, the relative
creation probability is the exponential of a quarter sum of the horizon areas
associated with the seed instanton.Comment: Report-no change onl
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