4,322 research outputs found
FACTOR DEMANDS OF LOUISIANA RICE PRODUCERS: AN ECONOMETRIC INVESTIGATION
A Diewert-flexible (dual) cost function was used to derive a system of conditional factor demand equations for Louisiana rice producers. Generalized Leontief cost and factor share equations were fitted for the 1955-87 period using Zellner's SURE system estimation procedure. The Aitken parameter estimates reveal that: (1) the optimal input mix of rice farmers varies with production scale, (2) the factor-augmenting technical change is labor and chemical saving but seed using, (3) pairwise input substitutions are limited, and (4) factor demands are own-price inelastic. An implication is that Louisiana rice farmers will not appreciably alter their factor utilizations when relative input prices change.Demand and Price Analysis,
Bootstrap and permutation tests of independence for point processes
Motivated by a neuroscience question about synchrony detection in spike train
analysis, we deal with the independence testing problem for point processes. We
introduce non-parametric test statistics, which are rescaled general
-statistics, whose corresponding critical values are constructed from
bootstrap and randomization/permutation approaches, making as few assumptions
as possible on the underlying distribution of the point processes. We derive
general consistency results for the bootstrap and for the permutation w.r.t. to
Wasserstein's metric, which induce weak convergence as well as convergence of
second order moments. The obtained bootstrap or permutation independence tests
are thus proved to be asymptotically of the prescribed size, and to be
consistent against any reasonable alternative. A simulation study is performed
to illustrate the derived theoretical results, and to compare the performance
of our new tests with existing ones in the neuroscientific literature
FACTOR DEMANDS OF LOUISIANA RICE PRODUCERS: AN ECONOMETRIC INVESTIGATION: REPLY
Demand and Price Analysis,
Obscured Asymptotic Giant Branch Variables in the Large Magellanic Cloud and the Period-Luminosity Relation
The characteristics of oxygen-rich and carbon-rich, large amplitude (dK>0.4
mag), asymptotic giant branch variables in the Large Magellanic Clouds are
discussed, with an emphasis on those obscured by dust. Near-infrared
photometry, obtained over about 8 years, is combined with published
mid-infrared observations from IRAS and ISO to determine bolometric magnitudes
for 42 stars. Pulsation periods of the O-rich stars are in the range 116<P<1393
days, while those for C-rich stars have 298<P<939 days. In addition to the
regular pulsations, one O-rich star and four C-rich stars show large amplitude,
dK> 0.6 mag, secular or very long period variations which may be associated
with changes in their mass-loss rates. We discuss and compare various methods
of determining the bolometric magnitudes and show, perhaps surprisingly, that
most of the very long period stars seem to follow an extrapolation of the
period-luminosity relation determined for stars with shorter periods - although
the details do depend on how the bolometric magnitudes are calculated. Three
stars with thin shells, which are clearly more luminous than the obscured AGB
stars, are undergoing hot bottom burning, while other stars with similar
luminosities have yet to be investigated in sufficient detail to determine
their status in this regard. We suggest that an apparent change in slope of the
period luminosity relation around 400-420 days is caused by variables with
luminosities brighter than the predictions of the core-mass luminosity
relation, due to excess flux from hot bottom burning.Comment: 20 pages, 20 figures, accepted for MNRA
Sexism in Special Education
The educational establishment is now reflecting the concerns of womanhood. Grudgingly, and even painfully, it seems to some, the large and complicated system of formal education acknowledges the existence of practices which are sexist both in conception and operation. At one level this sexism is directed, at many levels of awareness, toward the functionaries of the system. The economic oppression of teachers, who are mostly female, is an obvious expression of the phenomenon. Another benchmark is the limited career development opportunities available to women as educational managers and academics.
At yet another level, not the less dangerous for being more subtle, is the sexism directed toward the children and youth in its charge. It is this manifestation of sexism, the concepts and beliefs, the attitudes and practices about and toward children that result in sex-role stereotyping and discrimination, that is our primary concern and the major subje t of this analysis
Price Discount Perception: Consumers\u27 Numeric Interpretation of Semantic Price Claims
Behavioral pricing research includes a considerable amount of focus on the effects of semantic cues (phrases) used to label reference and offer prices in price promotions, but a related type of semantic claim also frequently used in price promotions has continued to escape research attention - claims that attempt to encourage purchases by describing the consequences of buying at the discounted price (e.g. Super Savings). Using a variety of methods and conceptual foundations, the present research is the first to comprehensively study consumers\u27 discount and value associations of these semantic claims. In a series of three studies, we find evidence suggesting that at least some semantic claims have consistent numerical interpretations and a subset of those were found to influence discount expectations and perceptions of both transaction and acquisition value. These findings suggest the importance of recognizing that consumers may associate specific claims with certain discount magnitudes
Surrogate data methods based on a shuffling of the trials for synchrony detection: the centering issue
International audienceWe investigate several distribution-free dependence detection procedures, all based on a shuffling of the trials, from a statistical point of view. The mathematical justification of such procedures lies in the bootstrap principle and its approximation properties. In particular, we show that such a shuffling has mainly to be done on centered quantities-that is, quantities with zero mean under independence-to construct correct p-values, meaning that the corresponding tests control their false positive (FP) rate. Thanks to this study, we introduce a method, named permutation UE, which consists of a multiple testing procedure based on permutation of experimental trials and delayed coincidence count. Each involved single test of this procedure achieves the prescribed level, so that the corresponding multiple testing procedure controls the false discovery rate (FDR), and this with as few assumptions as possible on the underneath distribution, except independence and identical distribution across trials. The mathematical meaning of this assumption is discussed, and it is in particular argued that it does not mean what is commonly referred in neuroscience to as cross-trials stationarity. Some simulations show, moreover, that permutation UE outperforms the trial-shuffling of Pipa and Grün ( 2003 ) and the MTGAUE method of Tuleau-Malot et al. ( 2014 ) in terms of single levels and FDR, for a comparable amount of false negatives. Application to real data is also provided
IKKα and IKKβ Each Function to Regulate NF-κB Activation in the TNF-Induced/Canonical Pathway
Activation of the transcription factor NF-kappaB by cytokines is rapid, mediated through the activation of the IKK complex with subsequent phosphorylation and degradation of the inhibitory IkappaB proteins. The IKK complex is comprised of two catalytic subunits, IKKalpha and IKKbeta, and a regulatory protein known as NEMO. Using cells from mice that are genetically deficient in IKKbeta or IKKalpha, or using a kinase inactive mutant of IKKbeta, it has been proposed that IKKbeta is critical for TNF-induced IkappaB phosphorylation/degradation through the canonical pathway while IKKalpha has been shown to be involved in the non-canonical pathway for NF-kappaB activation. These conclusions have led to a focus on development of IKKbeta inhibitors for potential use in inflammatory disorders and cancer.Analysis of NF-kappaB activation in response to TNF in MEFs reveals that IKKbeta is essential for efficient phosphorylation and subsequent degradation of IkappaB alpha, yet IKKalpha contributes to the NF-kappaB activation response in these cells as measured via DNA binding assays. In HeLa cells, both IKKalpha and IKKbeta contribute to IkappaB alpha phosphorylation and NF-kappaB activation. A kinase inactive mutant of IKKbeta, which has been used as evidence for the critical importance of IKKbeta in TNF-induced signaling, blocks activation of NF-kappaB induced by IKKalpha, even in cells that are deficient in IKKbeta.These results demonstrate the importance of IKKalpha in canonical NF-kappaB activation, downstream of cytokine treatment of cells. The experiments suggest that IKKalpha will be a therapeutic target in inflammatory disorders
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