1,853 research outputs found
Money, inflation and the Arab Spring in Bahrain
This paper investigates inflation in Bahrain during the period of the Arab Spring to determine effect of unrest on general and relative prices. We find first that the GDP deflator alone measures inflation in Bahrain; the CPI measures the cost of living only. Additionally, oil prices, the U.S. dollarâs trade-weighted value, and government price intervention are highly correlated with price movements. Disaggregated monthly CPI data reveal the onset of unrest is correlated with movements in several components of the CPI index, but the Arab Spring had its most direct and lasting causal effect solely on the housing.peer-reviewe
The covering number of
A finite cover of a group is a finite collection of proper subgroups of such that is equal to the union of all of the members of . Such a cover is called {\em minimal} if it has the smallest cardinality among all finite covers of . The covering number of , denoted by , is the number of subgroups in a minimal cover of . In this paper the covering number of the Mathieu group is shown to be 3336
Pursuing Cardiac Progenitors: Regeneration Redux
Recent studies have questioned the accepted dogma that the regenerative capacity of the heart following injury is limited. Several apparently distinct populations of resident cardiac progenitor cells may have the potential to regenerate functional heart muscle. Despite this progress, the physiologic role and therapeutic potential of cardiac resident progenitor cells remain unclear
Autocatalytic plume pinch-off
A localized source of buoyancy flux in a non-reactive fluid medium creates a
plume. The flux can be provided by either heat, a compositional difference
between the fluid comprising the plume and its surroundings, or a combination
of both. For autocatalytic plumes produced by the iodate-arsenous acid
reaction, however, buoyancy is produced along the entire reacting interface
between the plume and its surroundings. Buoyancy production at the moving
interface drives fluid motion, which in turn generates flow that advects the
reaction front. As a consequence of this interplay between fluid flow and
chemical reaction, autocatalytic plumes exhibit a rich dynamics during their
ascent through the reactant medium. One of the more interesting dynamical
features is the production of an accelerating vortical plume head that in
certain cases pinches-off and detaches from the upwelling conduit. After
pinch-off, a new plume head forms in the conduit below, and this can lead to
multiple generations of plume heads for a single plume initiation. We
investigated the pinch-off process using both experimentation and simulation.
Experiments were performed using various concentrations of glycerol, in which
it was found that repeated pinch-off occurs exclusively in a specific
concentration range. Autocatalytic plume simulations revealed that pinch-off is
triggered by the appearance of accelerating flow in the plume conduit.Comment: 10 figures. Accepted for publication in Phys Rev E. See also
http://www.physics.utoronto.ca/nonlinear/papers_chemwave.htm
Argonaute2 Is Essential for Mammalian Gastrulation and Proper Mesoderm Formation
Mammalian Argonaute proteins (EIF2C1â4) play an essential role in RNA-induced silencing. Here, we show that the loss of eIF2C2 (Argonaute2 or Ago2) results in gastrulation arrest, ectopic expression of Brachyury (T), and mesoderm expansion. We identify a genetic interaction between Ago2 and T, as Ago2 haploinsufficiency partially rescues the classic T/+ short-tail phenotype. Finally, we demonstrate that the ectopic T expression and concomitant mesoderm expansion result from disrupted fibroblast growth factor signaling, likely due to aberrant expression of Eomesodermin. Together, these data indicate that a factor best known as a key component of the RNA-induced silencing complex is required for proper fibroblast growth factor signaling during gastrulation, suggesting a possible micro-RNA function in the formation of a mammalian germ layer
Relating on-shell and off-shell formalism in perturbative quantum field theory
In the on-shell formalism (mostly used in perturbative quantum field theory)
the entries of the time ordered product T are on-shell fields (i.e. the basic
fields satisfy the free field equations). With that, (multi)linearity of T is
incompatible with the Action Ward identity. This can be circumvented by using
the off-shell formalism in which the entries of T are off-shell fields. To
relate on- and off-shell formalism correctly, a map sigma from on-shell fields
to off-shell fields was introduced axiomatically by Duetsch and Fredenhagen. In
that paper it was shown that, in the case of one real scalar field in N=4
dimensional Minkowski space, these axioms have a unique solution. However, this
solution was given there only recursively. We solve this recurrence relation
and give a fully explicit expression for sigma in the cases of the scalar,
Dirac and gauge fields for arbitrary values of the dimension N.Comment: The case of gauge fields was added. 16 page
Deuteronomy and Numbers
Four light isotopes - D, ^3He, ^4He and ^7Li - were produced by nuclear
reactions a few seconds after the big bang. New measurements of ^3He in the ISM
by Gloeckler and Geiss and of deuterium in high redshift hydrogen clouds by
Tytler and his collaborators provide further confirmation of big-bang
nucleosynthesis and new insight about the density of ordinary matter (baryons).Comment: 6 pages LaTeX with 1 eps Figur
Concentrations of Polychlorinated Biphenyls (PCBâs), Chlorinated Pesticides, and Heavy Metals and Other Elements in Tissues of Belugas, Delphinapterus leucas, from Cook Inlet
Tissues from Cook Inlet beluga whales, Delphinapterus leucas, that were collected as part of the Alaska Marine Mammal Tissue Archival Project were analyzed for polychlorinated biphenyls (PCBâs), chlorinated pesticides, and heavy metals and other elements. Concentrations of total PCBâs (ÎŁPCBâs), total DDT (ÎŁDDT), chlordane compounds, hexachlorobenzene (HCB), dieldrin, mirex, toxaphene, and hexachlorocyclohexane (HCH) measured in Cook Inlet beluga blubber were compared with those reported for belugas from two Arctic Alaska locations (Point Hope and Point Lay), Greenland, Arctic Canada, and the highly contaminated stock from the St. Lawrence estuary in eastern Canada. The Arctic and Cook Inlet belugas had much lower concentrations (ÎŁPCBâs and ÎŁDDT were an order of magnitude lower) than those found in animals from the St. Lawrence estuary. The Cook Inlet belugas had the lowest concentrations of all (ÎŁPCBâs aver-aged 1.49 ± 0.70 and 0.79 ± 0.56 mg/kg wet mass, and ÎŁDDT averaged 1.35 ± 0.73 and 0.59 ± 0.45 mg/kg in males and females, respectively). Concentrations in the blubber of the Cook Inlet males were significantly lower than those found in the males of the Arctic Alaska belugas (ÎŁPCBâs and ÎŁDDT were about half). The lower levels in the Cook Inlet animals might be due to differences in contaminant sources, food web differences, or different age distributions among the animals sampled. Cook Inlet males had higher mean and median concentrations than did females, a result attributable to the transfer of these compounds from mother to calf during pregnancy and during lactation. Liver concentrations of cadmium and mercury were lower in the Cook Inlet belugas (most cadmium values were <1 mg/kg and mercury values were 0.704â11.42 mg/kg wet mass), but copper levels were significantly higher in the Cook Inlet animals (3.97â123.8 mg/kg wet mass) than in Arctic Alaska animals and similar to those reported for belugas from Hudson Bay. Although total mercury levels were the lowest in the Cook Inlet population, methylmercury concentrations were similar among all three groups of the Alaska animals examined (0.34â2.11 mg/kg wet mass). As has been reported for the Point Hope and Point Lay belugas, hepatic concentrations of silver were r
Protecting the conformal symmetry via bulk renormalization on Anti deSitter space
The problem of perturbative breakdown of conformal symmetry can be avoided,
if a conformally covariant quantum field phi on d-dimensional Minkowski
spacetime is viewed as the boundary limit of a quantum field Phi on
d+1-dimensional anti-deSitter spacetime (AdS). We study the boundary limit in
renormalized perturbation theory with polynomial interactions in AdS, and point
out the differences as compared to renormalization directly on the boundary. In
particular, provided the limit exists, there is no conformal anomaly. We
compute explicitly the "fish diagram" on AdS_4 by differential renormalization,
and calculate the anomalous dimension of the composite boundary field phi^2
with bulk interaction Phi^4.Comment: 40 page
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