2,245 research outputs found
Characterization of Cre recombinase activity for in vivo targeting of adipocyte precursor cells.
The increased incidence of obesity and metabolic disease underscores the importance of elucidating the biology of adipose tissue development. The recent discovery of cell surface markers for prospective identification of adipose precursor cells (APCs) in vivo will greatly facilitate these studies, yet tools for specifically targeting these cells in vivo have not been identified. Here, we survey three transgenic mouse lines, Fabp4-Cre, PdgfRα-Cre, and Prx1-Cre, precisely assessing Cre-mediated recombination in adipose stromal populations and mature tissues. Our data provide key insights into the utility of these tools to modulate gene expression in adipose tissues. In particular, Fabp4-Cre is not effective to target APCs, nor is its activity restricted to these cells. PdgfRα-Cre directs recombination in the vast majority of APCs, but also targets other populations. In contrast, adipose expression of Prx1-Cre is chiefly limited to subcutaneous inguinal APCs, which will be valuable for dissection of APC functions among adipose depots
Milk Price Volatility and its Determinants
The classified pricing of fluid milk under the Federal Milk Marketing Orders (FMMO) system combined with the cash settlement feature of Class IIII milk futures contracts generate a unique volatility pattern of these futures markets in the sense that the volatility gradually decreases as the USDA price announcement dates approaching in the month. Focusing on the evolution of volatility in Class III milk futures market, this study quantifies the relative importance of a set of factors driving milk price variation. While volatilities in both corn futures market and financial market Granger-cause the milk price volatility, the impact of financial market is more persistent. Besides embedded seasonality, market demand and supply conditions in the dairy market, cheese in this case, as well as changes in the U.S. exchange rates are found to have positive and statistically significant impacts on milk price volatility. While speculation positively affects milk futures markets, the effect was found insignificant.Cash settlement, impulse responses, milk pricing, realized volatility, speculation, Agricultural and Food Policy, Q11, Q14.,
Nonlinear tube-fitting for the analysis of anatomical and functional structures
We are concerned with the estimation of the exterior surface and interior
summaries of tube-shaped anatomical structures. This interest is motivated by
two distinct scientific goals, one dealing with the distribution of HIV
microbicide in the colon and the other with measuring degradation in
white-matter tracts in the brain. Our problem is posed as the estimation of the
support of a distribution in three dimensions from a sample from that
distribution, possibly measured with error. We propose a novel tube-fitting
algorithm to construct such estimators. Further, we conduct a simulation study
to aid in the choice of a key parameter of the algorithm, and we test our
algorithm with validation study tailored to the motivating data sets. Finally,
we apply the tube-fitting algorithm to a colon image produced by single photon
emission computed tomography (SPECT) and to a white-matter tract image produced
using diffusion tensor imaging (DTI).Comment: Published in at http://dx.doi.org/10.1214/10-AOAS384 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
An exact category approach to Hecke endomorphism algebras
Let be a finite group of Lie type. In studying the cross-characteristic
representation theory of , the (specialized) Hecke algebra
H=\End_G(\ind_B^G1_B) has played a important role. In particular, when
is a finite general linear group, this approach led to
the Dipper-James theory of -Schur algebras . These algebras can be
constructed over \sZ:=\mathbb Z[t,t^{-1}] as the -analog (with ) of
an endomorphism algebra larger than , involving parabolic subgroups. The
algebra is quasi-hereditary over \sZ. An analogous algebra, still denoted
, can always be constructed in other types. However, these algebras have so
far been less useful than in the case, in part because they are not
generally quasi-hereditary.
Several years ago, reformulating a 1998 conjecture, the authors proposed (for
all types) the existence of a \sZ-algebra having a stratified derived
module category, with strata constructed via Kazhdan-Lusztig cell theory. The
algebra is recovered as for an idempotent . A main goal
of this monograph is to prove this conjecture completely. The proof involves
several new homological techniques using exact categories. Following the proof,
we show that does become quasi-hereditary after the inversion of the bad
primes. Some first applications of the result -- e.g., to decomposition
matrices -- are presented, together with several open problems.Comment: 144 page
MODELING STATISTICALLY SIGNIFICANT PROPENSITY CONTROLS
A mechanism for modeling statistically significant propensity controls in survey lift studies is disclosed. The proposed mechanism establishes a statistically significant control model for organic viewers in order to measure attitudinal shifts and lift from the viewing population. On a high level, audience overlap is measured to find channels that are similar to the channels in an organic video campaign. Active subscribers of the identified similar channels are then used as the non-exposed group, after filtering out those who watched the organic videos. The resulting channels that share viewer audiences are filtered by channel topicality (e.g., electronics reviews, beauty tips, etc.) and channel size (subscribers within a standard deviation). Viewers are filtered by demographic, technographic and psychographic traits to align with that of the exposed groups
Institutional Development and Foreign Banks in Chile
This paper analyzes the effects of foreign banks on developing countries’ bank performance. We study this relationship from a different perspective by focusing on Chile, an emerging market with strong institutions. The results from dynamic panel regressions on hand-collected financial statement data from 2005 to 2014 indicate that foreign banks improve banking sector competitiveness, reduce the volatility of returns, and increase commercial and consumption loans. The overall evidence suggests that, in the presence of solid institutions, foreign banks improve the banking sector in developing countries. Therefore, public policies on foreign banks should be more effective when accompanied by advances in institutions
Nonclassical paths in the recurrence spectrum of diamagnetic atoms
Using time-independent scattering matrices, we study how the effects of
nonclassical paths on the recurrence spectra of diamagnetic atoms can be
extracted from purely quantal calculations. This study reveals an intimate
relationship between two types of nonclassical paths: exotic ghost orbits and
diffractive orbits. This relationship proves to be a previously unrecognized
reason for the success of semiclassical theories, like closed-orbit theory, and
permits a comprehensive reformulation of the semiclassical theory that
elucidates its convergence properties.Comment: 5 pages, 4 figure
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