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81.
N. Mielenz 《Biometrical journal. Biometrische Zeitschrift》1984,26(1):1-12
In this paper the problem of unistage selection with inequality constraints is formulated. If the predictor and criterion variables are all normally distributed, this problem can be written as a convex programming problem, with a linear objective function and with linear constraints and a quadratic constraint. Using the duality theory, for convex nonlinear programming it is proved, that its dual problem can be transformed into a convex minimization problem with non-negativity conditions. Good computational methods are known for solving this problem. By the help of the dual problem sufficient conditions for a solution of the original primal problem are derived and illustrated by an example of practical interest. 相似文献
82.
Gabriela Caballero 《Morphology》2006,16(2):273-289
Although a wide array of phonological properties seem to backcopy in reduplication, it is an open question whether reduplicative
templates can backcopy as well. It has been argued that natural languages do not have reduplicative
constructions where the base truncates to match the truncated reduplicant (McCarthy & Prince, 1994; McCarthy & Prince, 1999;
Spaelti, 1997; inter alia). In Guarijio Abbreviated Reduplication (Miller, 1996), however, both copies of the reduplicative
construction truncate, instantiating the pattern that has been claimed not to exist. This paper argues that the Guarijio case
fills this typological gap. Although the data can be given a templatic backcopying analysis, this paper defends a Morphological
Doubling Theory (MDT) analysis using cophonologies (Inkelas & Zoll, 2005). In MDT, Guarijio Abbreviated Reduplication results
from the parallel imposition of a truncating cophonology in each copy of the reduplicative construction. Guarijio Abbreviated
Reduplication is predicted to exist by MDT together with other documented cases of parallel phonological modification in reduplication.
I am grateful to many people for helpful comments and suggestions, including Isabel Barreras Aguilar, Laura Downing, Nicholas
Fleisher, Andrew Garrett, Jason Haugen, Larry Hyman, Yuni Kim, Teresa McFarland, David Mortensen, Mary Paster, Eric Raimy,
and Timothy Thornes as well as the audience of the LSA 2005 Annual Meeting in Oakland. I would like to extend a special thanks
to Alan Yu for his detailed comments and suggestions to latter versions of this paper. I am particularly indebted to Sharon
Inkelas, for her generous advice, feedback, and numerous discussions throughout the development of this paper. I am also grateful
to two anonymous reviewers for their comments and criticisms, and especially to Ingo Plag for his patience and detailed suggestions
as editor. All remaining errors and omissions are mine. This study was made possible by fellowships by CONACYT (Consejo Nacional
de Ciencia y Tecnología, México), the University of California Institute for Mexico and the United States (UCMEXUS) and Fulbright. 相似文献
83.
Neural correlates of behavioral gap detection in the inferior colliculus of the young CBA mouse 总被引:6,自引:0,他引:6
J. P. Walton R. D. Frisina J. R. Ison W. E. O'Neill 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1997,181(2):161-176
The gap detection paradigm is frequently used in psychoacoustics to characterize the temporal acuity of the auditory system.
Neural responses to silent gaps embedded in white-noise carriers, were obtained from mouse inferior colliculus (IC) neurons
and the results compared to behavioral estimates of gap detection. Neural correlates of gap detection were obtained from 78
single neurons located in the central nucleus of the IC. Minimal gap thresholds (MGTs) were computed from single-unit gap
functions and were found to be comparable, 1–2 ms, to the behavioral gap threshold (2 ms). There was no difference in MGTs
for units in which both carrier intensities were collected. Single unit responses were classified based on temporal discharge
patterns to steady-state noise bursts. Onset and primary-like units had the shortest mean MGTs (2.0 ms), followed by sustained
units (4.0 ms) and phasic-off units (4.2 ms). The longest MGTs were obtained for inhibitory neurons (xˉ = 14 ms). Finally,
the time-course of behavioral and neurophysiological gap functions were found to be in good agreement. The results of the
present study indicate the neural code necessary for behavioral gap detection is present in the temporal discharge patterns
of the majority of IC neurons.
Accepted: 6 February 1997 相似文献
84.
Louise Shaxson 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2009,364(1526):2141-2151
How can we strengthen the science–policy interface for plastics, the environment and human health? In a complex policy area with multiple stakeholders, it is important to clarify the nature of the particular plastics-related issue before trying to understand how to reconcile the supply and demand for evidence in policy. This article proposes a simple problem typology to assess the fundamental characteristics of a policy issue and thus identify appropriate processes for science–policy interactions. This is illustrated with two case studies from one UK Government Department, showing how policy and science meet over the environmental problems of plastics waste in the marine environment and on land. A problem-structuring methodology helps us understand why some policy issues can be addressed through relatively linear flows of science from experts to policymakers but why others demand a more reflexive approach to brokering the knowledge between science and policy. Suggestions are given at the end of the article for practical actions that can be taken on both sides. 相似文献
85.
The formulation, content, and corollaries of the so-called kT problem are considered. The problem points to a paradox in the biological effect of weak low-frequency magnetic fields. The conventional formulation of the problem contains implicit assumptions that prove not fully valid according to the results of analysis. 相似文献
86.
87.
In Heikinheimo et al . ( Journal of Biogeography , 2007, 34 , 1053–1064) we used clustering to analyse European land mammal fauna. Gagné & Proulx criticized our choice of the Euclidean distance measure in the analysis, and advocated the use of the Hellinger distance measure, claiming that this leads to very different clustering results. The criticism fails to take into account the probabilistic nature of the methods used and the fact that in this case the similarity measures correlate strongly. Gagné & Proulx used subjective inspection as the criterion of similarity between clusterings. We show that this is insufficient and misleading. Namely, owing to the local minimum problem, two clustering runs rarely give identical results. In the case of our study, the measured similarity (using the kappa statistic) between the Euclidean- and Hellinger-based clusterings is roughly equal to the similarity between two clusterings that both use the Hellinger distance but different random initialization points. 相似文献
88.
微生态调节剂质量标准探讨 总被引:1,自引:0,他引:1
微生态调节剂质量标准探讨浙江省药品检验所浙江310004邵惠琴王知坚微生态学是研究生物体与其体内环境的微生态平衡、失调,调整的一门新形成的生命科学分支。我国自80年代提出来后得到了很快的发展,近年来与之相适应的各种药用微生物制剂也应运而生,且发展迅速... 相似文献
89.
In this report we investigated whether the modulation of drug permeability in Chinese hamster ovary (CHO) cells was an energy-dependent process. We observed that (1) in the absence of glucose, metabolic inhibitors such as cyanide, azide, and dinitrophenol stimulated the uptake of [3H]colchicine and other drug; (2) cyanide-induced stimulation of drug uptake could be prevented by the presence of metabolizable sugars such as glucose and ribose; (3) cyanide-treated cells were fully viable; (4) on the addition of cyanide and glucose the kinetics of drug permeability changes were very rapid. These data are consistent with the hypothesis that an energy-dependent membrane barrier against the uptake of a variety of drugs was operative in CHO cells.The nature of this energy-dependent membrane barrier was examined in colchicine-resistant mutants (CHRC4 and CHRC5 cells) previously characterized as membrane mutants with greatly reduced drug permeability (Ling and Thompson, (1974) J. Cell Physiol. 83, 103–116). The mutants were more refractile to the cyanide-induced stimulation of drug permeability but more sensitive to the glucose prevention cyanide-induction. In the presence of cyadine, the uptake rate of [3H] colchicine by CHRC4 cells increased by about 100-fold and approached a rate similar to that of wild-type cells. These results suggest that the colchicine-resistant mutants may be altered in their energy-dependent modulation of drug permeability. 相似文献
90.
During four decades (1960–1990s), the conceptualization and experimental design of studies in kin recognition relied on work with multicellular eukaryotes, particularly Unikonta (including invertebrates and vertebrates) and some Bikonta (including plants). This pioneering research had an animal behavior approach. During the 2000s, work on taxa‐, clone‐ and kin‐discrimination and recognition in protists produced genetic and molecular evidence that unicellular organisms (e.g. Saccharomyces, Dictyostelium, Polysphondylium, Tetrahymena, Entamoeba and Plasmodium) could distinguish between same (self or clone) and different (diverse clones), as well as among conspecifics of close or distant genetic relatedness. Here, we discuss some of the research on the genetics of kin discrimination/recognition and highlight the scientific progress made by switching emphasis from investigating multicellular to unicellular systems (and backwards). We document how studies with protists are helping us to understand the microscopic, cellular origins and evolution of the mechanisms of kin discrimination/recognition and their significance for the advent of multicellularity. We emphasize that because protists are among the most ancient organisms on Earth, belong to multiple taxonomic groups and occupy all environments, they can be central to reexamining traditional hypotheses in the field of kin recognition, reformulating concepts, and generating new knowledge. 相似文献