4,298 research outputs found
Federal Home Loan Bank Advances and Small Business Lending
Adequate credit availability for small businesses is an important public policy issue because small businesses are essential for employment and economic growth for the economy. The Gramm-Leach-Bliley Act of 1999 includes a provision that could potentially support financial institutions in the provision of credit to small businesses through the use of advances from the Federal Home Loan Bank (FHLB) system that are secured with small business loans. We explore the relation between FHLB advances to financial institutions and the provision of loans to small businesses. We find a positive link between the change in FHLB advances and the change in small business loans and the level of FHLB advances and the level of small business loans. This relation holds for large and small banks and pre- and post-2007 recession. However, we find that the change in the proportion of small business loans to assets is only positively related to the change in the advances to assets ratio prior to the recessionary period. This suggests that banks substitute small business loans for other types of assets during relatively normal economic periods, but FHLB advances are a source of wholesale funds that will be invested in the most attractive financial assets available with no preference for any particular asset during periods of contracting credit
Topology of the Spin-polarized Charge Density in bcc and fcc Iron
We investigate the topology of the spin-polarized charge density in bcc and
fcc iron. While the total spin-density is found to possess the topology of the
non-magnetic prototypical structures, in some cases the spin-polarized
densities are characterized by unique topologies; for example, the
spin-polarized charge densities of bcc and high-spin fcc iron are atypical of
any known for non-magnetic materials. In these cases, the two spin-densities
are correlated: the spin-minority electrons have directional bond paths with
deep minima in the minority density, while the spin-majority electrons fill
these holes, reducing bond directionality. The presence of two distinct spin
topologies suggests that a well-known magnetic phase transition in iron can be
fruitfully reexamined in light of these topological changes. We show that the
two phase changes seen in fcc iron (paramagnetic to low-spin and low-spin to
high-spin) are different. The former follows the Landau symmetry-breaking
paradigm and proceeds without a topological transformation, while the latter
also involves a topological catastrophe.Comment: 5 pages, 3 figures. Phys. Rev. Lett. (in press
Electronic Selection Rules Controlling Dislocation Glide in bcc Metals
The validity of the structure-property relationships governing the
deformation behavior of bcc metals was brought into question with recent {\it
ab initio} density functional studies of isolated screw dislocations in Mo and
Ta. These existing relationships were semiclassical in nature, having grown
from atomistic investigations of the deformation properties of the groups V and
VI transition metals. We find that the correct form for these
structure-property relationships is fully quantum mechanical, involving the
coupling of electronic states with the strain field at the core of long
screw dislocations.Comment: 4 pages, 2 figure
Cellular FLICE-like inhibitory protein (C-FLIP): a novel target for cancer therapy
Cellular FLICE-like inhibitory protein (c-FLIP) has been identified as a protease-dead, procaspase-8-like regulator of death ligand-induced apoptosis, based on observations that c-FLIP impedes tumor necrosis factor-alpha (TNF-alpha), Fas-L, and TNF-related apoptosis-inducing ligand (TRAIL)-induced apoptosis by binding to FADD and/or caspase-8 or -10 in a ligand-dependent fashion, which in turn prevents death-inducing signaling complex (DISC) formation and subsequent activation of the caspase cascade. c-FLIP is a family of alternatively spliced variants, and primarily exists as long (c-FLIP(L)) and short (c-FLIP(S)) splice variants in human cells. Although c-FLIP has apoptogenic activity in some cell contexts, which is currently attributed to heterodimerization with caspase-8 at the DISC, accumulating evidence indicates an anti-apoptotic role for c-FLIP in various types of human cancers. For example, small interfering RNAs (siRNAs) that specifically knocked down expression of c-FLIP(L) in diverse human cancer cell lines, e.g., lung and cervical cancer cells, augmented TRAIL-induced DISC recruitment, and thereby enhanced effector caspase stimulation and apoptosis. Therefore, the outlook for the therapeutic index of c-FLIP-targeted drugs appears excellent, not only from the efficacy observed in experimental models of cancer therapy, but also because the current understanding of dual c-FLIP action in normal tissues supports the notion that c-FLIP-targeted cancer therapy will be well tolerated. Interestingly, Taxol, TRAIL, as well as several classes of small molecules induce c-FLIP downregulation in neoplastic cells. Efforts are underway to develop small-molecule drugs that induce c-FLIP downregulation and other c-FLIP-targeted cancer therapies. In this review, we assess the outlook for improving cancer therapy through c-FLIP-targeted therapeutics
Isolating the enhanced memory of a glassy system
Studies of glassy systems have shown how cyclic driving forms memories of
amplitude. We explore how choice of driving protocol reveals dramatically
different features of this memory. We model rearranging soft spots in sheared
amorphous solids as hysterons. Cyclic shear with positive and negative shear
strain reveals a return-point memory of multiple strains known from experiments
and molecular dynamics simulations, while asymmetric driving (e.g. only
positive shear strains) suppresses multiple memories. However, when we
introduce frustrated interactions between hysterons, we identify a different
mechanism that restores multiple memories for asymmetric driving and can be
used for design. Our work suggests that this enhanced memory is a signature of
frustration.Comment: 5 pages, 5 figure
Identification of Extra Neutral Gauge Bosons at the LHC Using b- and t-Quarks
New Neutral Gauge Bosons, Z' 's, are predicted by many models of physics
beyond the Standard Electroweak Theory. It is possible that a Z' would be
discovered early in the Large Hadron Collider program. The next step would be
to measure its properties to identify the underlying theory that gave rise to
the Z'. Heavy quarks have the unique property that they can be identified in
the final states. In this letter we demonstrate that measuring Z' decays to b-
and t-quark final states can act as an effective means of discriminating
between models with extra gauge bosons.Comment: 5 pages, 4 figures, references added and minor clarification
Grain Physics and Rosseland Mean Opacities
Tables of mean opacities are often used to compute the transfer of radiation
in a variety of astrophysical simulations from stellar evolution models to
proto-planetary disks. Often tables, such as Ferguson et al. (2005), are
computed with a predetermined set of physical assumptions that may or may not
be valid for a specific application. This paper explores the effects of several
assumptions of grain physics on the Rosseland mean opacity in an oxygen rich
environment. We find that changing the distribution of grain sizes, either the
power-law exponent or the shape of the distribution, has a marginal effect on
the total mean opacity. We also explore the difference in the mean opacity
between solid homogenous grains and grains that are porous or conglomorations
of several species. Changing the amount of grain opacity included in the mean
by assuming a grain-to-gas ratio significantly affects the mean opacity, but in
a predictable way.Comment: 19 pages, 6 figures, accepted for publication in Ap
Human β-galactoside α-2,3-sialyltransferase (ST3Gal III) attenuated Taxol-induced apoptosis in ovarian cancer cells by downregulating caspase-8 activity
Taxol triggers apoptosis in a variety of cancer cells, but it also upregulates cytoprotective proteins and/or pathways that compromise its therapeutic efficacy. In this report, we found that Taxol treatment resulted in caspase-8-dependent apoptosis in SKOV3 human ovarian cancer cells. Moreover, Taxol-induced apoptosis was associated with caspase-3 activation. Interestingly, Taxol treatment upregulated α-2,3-sialyltransferase (ST3Gal III) expression and forced expression of ST3Gal III attenuated Taxol-induced apoptosis. Furthermore, ST3Gal III overexpression inhibited Taxol-ttiggered caspase-8 activation, indicating that ST3Gal III upregulation produces cellular resistance to Taxol and hence reduces the efficacy of Taxol therapy
Configurational temperature control for atomic and molecular systems
A new configurational temperature thermostat suitable for molecules with holonomic constraints is derived. This thermostat has a simple set of motion equations, can generate the canonical ensemble in both position and momentum space, acts homogeneously through the spatial
coordinates, and does not intrinsically violate the constraints. Our new configurational thermostat is
closely related to the kinetic temperature Nosé-Hoover thermostat with feedback coupled to the position variables via a term proportional to the net molecular force. We validate the thermostat by comparing equilibrium static and dynamic quantities for a fluid of n-decane molecules under
configurational and kinetic temperature control. Practical aspects concerning the implementation of the new thermostat in a molecular dynamics code and the potential applications are discussed
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