Showing papers by "University of Wisconsin-Madison published in 1987"
TL;DR: If data augmentation can be used in the calculation of the maximum likelihood estimate, then in the same cases one ought to be able to use it in the computation of the posterior distribution of parameters of interest.
Abstract: The idea of data augmentation arises naturally in missing value problems, as exemplified by the standard ways of filling in missing cells in balanced two-way tables. Thus data augmentation refers to a scheme of augmenting the observed data so as to make it more easy to analyze. This device is used to great advantage by the EM algorithm (Dempster, Laird, and Rubin 1977) in solving maximum likelihood problems. In situations when the likelihood cannot be approximated closely by the normal likelihood, maximum likelihood estimates and the associated standard errors cannot be relied upon to make valid inferential statements. From the Bayesian point of view, one must now calculate the posterior distribution of parameters of interest. If data augmentation can be used in the calculation of the maximum likelihood estimate, then in the same cases one ought to be able to use it in the computation of the posterior distribution. It is the purpose of this article to explain how this can be done. The basic idea ...
4,020 citations
TL;DR: Seventy-two percent of eyes of younger onset and 45% of Eyes of older onset persons that had received panretinal photocoagulation treatment were found to have incomplete regression of retinal new vessels, and in approximately half of these eyes severe proliferative retinopathy (Diabetic Retinopathy Study High Risk Characteristics [DRS-HRC]) was present.
1,305 citations
TL;DR: In this paper, the authors present the basic model of an agricultural household that underlies most of the case studies undertaken so far, assuming that households are price-takers and is therefore recursive.
Abstract: This book presents the basic model of an agricultural household that underlies most of the case studies undertaken so far. The model assumes that households are price-takers and is therefore recursive. The decisions modeled include those affecting production and the demand for inputs and those affecting consumption and the supply of labor. Comparative results on selected elasticities are presented for a number of economies. The empirical significance of the approach is demonstrated in a comparison of models that treat production and consumption decisions separately and those in which the decisionmaking process is recursive. The book summarizes the implications of agricultural pricing policy for the welfare of farm households, marketed surplus, the demand for nonagricultural goods and services, the rural labor market, budget revenues, and foreign exchange earnings. In addition, it is shown that the basic model can be extended in order to explore the effects of government policy on crop composition, nutritional status, health, saving, and investment and to provide a more comprehensive analysis of the effects on budget revenues and foreign exchange earnings. Methodological topics, primarily the data requirements of the basic model and its extensions, along with aggregation, market interaction, uncertainty, and market imperfections are discussed. The most important methodological issues - the question of the recursive property of these models - is also discussed.
1,242 citations
TL;DR: The authors discusses the psychology of risk: what risk is (if it is anything at all), how people think about it, what they feel about it and what they do about it.
Abstract: Publisher Summary This chapter discusses the psychology of risk: what risk is (if it is anything at all), how people think about it, what they feel about it, and what they do about it. The chapter describes the way psychologists think about risk: how they study it, what tasks they use, what factors they vary, and what models they build (or borrow) to describe risk-taking behavior. Technically, the word risk refers to situations in which a decision is made whose consequences depend on the outcomes of future events having known probabilities. Psychological studies of risky choice (it is the term used conventionally to refer to all but the most extreme instances of ignorance or ambiguity) fall into two groups. At one extreme are the studies run by mathematically inclined experimental psychologists in which subjects make decisions about gambles described in terms of amounts and probabilities. At the other extreme are studies run by personality psychologists, who are mostly interested in individual differences in risk taking. A theory of risky choice is presented in the chapter that attempts to meld the strengths of both approaches. Empirically and methodologically it is tied to the experimental approach to risky choice. But theoretically it is more strongly tied to motivational approaches.
1,122 citations
TL;DR: Fried ground beef contains substances that inhibit mutagenesis in bacteria and the initiation of epidermal carcinogenesis in mice by 7,12-dimethylbenz [a]anthracene (DMBA), and CLA-treated mice developed only about half as many papillomas and exhibited a lower tumor incidence compared with the control mice.
Abstract: Fried ground beef contains substances that inhibit mutagenesis in bacteria and the initiation of epidermal carcinogenesis in mice by 7,12-dimethylbenz [a]anthracene (DMBA). The inhibitors apparently act at least in part via inhibition of cytochrome P-450 activity. A highly purified fraction that inhibited cytochrome P-450 activity in vitro was isolated by HPLC and characterized by GC-MS, and by UV and proton NMR spectroscopy. The fraction contained four isomeric derivatives of linoleic acid each containing a conjugated double-bond system (designated CLA). Synthetically prepared CLA (containing all four isomers) was tested for anti-initiation activity in the two-stage mouse epidermal carcinogenesis system. Seven days, 3 days and 5 min prior to DMBA application, CLA was applied at doses of 20, 20 and 10 mg respectively. Control mice were treated similarly with linoleic acid or solvent (acetone). One week after initiation, and twice weekly thereafter, all mice were treated with 12-O-tetradecanoylphorbol-13-acetate to effect tumor promotion. There was no difference in tumor incidence or yield between linoleic acid-treated mice and solvent-treated control mice. By contrast, the CLA-treated mice developed only about half as many papillomas and exhibited a lower tumor incidence compared with the control mice.
949 citations
TL;DR: While fitness regression permits direct assessment of selection in a form suitable for predicting selection response, it is suggested that the aim of inferring causal relationships about the effects of phenotypic characters on fitness is greatly facilitated by manipulative experiments.
Abstract: Recent theoretical work in quantitative genetics has fueled interest in measuring natural selection in the wild. We discuss statistical and biological issues that may arise in applications of Lande and Arnold's (1983) multiple-regression approach to measuring selection. We review assumptions involved in estimation and hypothesis testing in regression problems, and we note difficulties that frequently arise as a result of violation of these assumptions. In particular, multicollinearity (extreme intercorrelation of characters) and extrinsic, unmeasured factors affecting fitness may seriously complicate inference regarding selection. Further, violation of the assumption that residuals are normally distributed vitiates tests of significance. For this situation, we suggest applications of recently developed jackknife tests of significance. While fitness regression permits direct assessment of selection in a form suitable for predicting selection response, we suggest that the aim of inferring causal relationships about the effects of phenotypic characters on fitness is greatly facilitated by manipulative experiments. Finally, we discuss alternative definitions of stabilizing and disruptive selection.
892 citations
TL;DR: In this paper, a detailed analysis of W pair production in e+e− annihilation at LEP-II energies is presented by using helicity amplitudes for the process e−e−→W+W− with arbitrary WWγ and WWZ couplings.
831 citations
TL;DR: This work uses gene targetting functionally to correct the mutant hypoxanthine-guanine phosphoribosyl transferase (HPRT) gene in the ES cell line which has previously been isolated and used to produce an HPRT-deficient mouse5.
Abstract: Two recent developments suggest a route to predetermined alterations in mammalian germlines. These are, first, the characterization of mouse embryonic stem (ES) cells that can still enter the germline after genetic manipulation in culture and second, the demonstration that homologous recombination between a native target chromosomal gene and exogenous DAN can be used in culture to modify specifically the target locus. We here use gene targetting functionally to correct the mutant hypoxanthine-guanine phosphoribosyl transferase (HPRT) gene in the ES cell line which has previously been isolated and used to produce an HPRT-deficient mouse. This modification of a chosen gene in pluripotent ES cells demonstrates the feasibility of this route to manipulating mammalian genomes in predetermined ways.
802 citations
TL;DR: Much can be learned from combining or pooling data but it must be done cautiously, and substantial scientific input is required as to what criteria must be met by each potential study.
Abstract: Methods for combining data from several studies exist and appear to be quite useful. None satisfactorily addresses the question of what studies should be combined. This issue is the most serious methodological limitation. Even studies with statistically significant interaction might still be combined if the effect were in the same direction. Thus, substantial scientific input is required as to what criteria must be met by each potential study. Much can be learned from combining or pooling data but it must be done cautiously. Pooling exercises do not replace well designed prospective clinical trials. Efforts for establishing basic design criteria to allow for multicentre and multicountry trials to be more easily combined might be useful.
772 citations
TL;DR: In this article, bounds on asymptotic efficiency are derived for a class of nonparametric models, where the data are independent and identically distributed according to some unknown distribution F. This bound turns out to depend only upon certain conditional moments, and not upon the support of the distribution.
769 citations
TL;DR: This paper proposed a componential model in which emotions are seen to develop from simpler, reflex-like forms (wired-in) sensory-motor processes to complex cognitive-emotional patterns that result from the participation of at least two distinct levels of memory and information processing, a schematic and a conceptual level.
Abstract: We first review the main points in the dispute about whether emotion is primary and independent of cognition (Zajonc), or secondary and always dependent upon cognition (Lazarus), and suggest that the dispute is largely one of definition. Because definitional disputes seldom clarify substantive, theoretical points, we suggest a variety of questions regarding cognition-emotion interaction. To stimulate discussion of these issues, we propose a componential model in which emotions are seen to develop from simpler, reflex-like forms (“wired-in” sensory-motor processes) to complex cognitive-emotional patterns that result from the participation of at least two distinct levels of memory and information processing, a schematic and a conceptual level. These systems are typically activated by a continuous stimulus check process which evaluates five environment-organism attributes: novelty; pleasantness; goal conductiveness; coping potential; and consistency with social norms and self-relevant values. Questi...
TL;DR: It is proposed that glp-1 acts as part of the receiving mechanism in the interaction between the distal tip cell and germ line, and is produced in the germ line.
TL;DR: The authors showed that mental models are operative during text comprehension and that they represent what the text is about (the events, objects, and processes described in the text), rather than features of the text itself.
TL;DR: The results indicate that mood state disturbances increased in a dose-response manner as the training stimulus increased and that these mood disturbances fell to baseline levels with reduction of the training load.
Abstract: It is widely agreed that overtraining should be employed in order to achieve peak performance but it is also recognised that overtraining can actually produce decrements in performance. The challenge appears to be one of monitoring stress indicators in the athlete in order to titrate the training stimulus and prevent the onset of staleness. The present paper summarises a ten-year research effort in which the mood states of competitive swimmers have been monitored at intervals ranging from 2-4 weeks during individual seasons for the period 1975-1986. The training cycle has always involved the indoor season which extends from September to March and the athletes who served as subjects were 200 female and 200 male competitive swimmers. The results indicate that mood state disturbances increased in a dose-response manner as the training stimulus increased and that these mood disturbances fell to baseline levels with reduction of the training load. Whilst these results have been obtained in a realistic setting devoid of experimental manipulation, it is apparent that monitoring of mood state provides a potential method of preventing staleness.
01 Jan 1987
TL;DR: In this paper, the authors describe a malicious download of the dynamics of polymeric liquids volume 1 fluid mechanics vol 1, but end up in malicious downloads, rather than reading a good book with a cup of coffee in the afternoon, instead they are facing with some harmful virus inside their desktop computer.
Abstract: Thank you very much for downloading dynamics of polymeric liquids volume 1 fluid mechanics vol 1. Maybe you have knowledge that, people have look numerous times for their chosen readings like this dynamics of polymeric liquids volume 1 fluid mechanics vol 1, but end up in malicious downloads. Rather than reading a good book with a cup of coffee in the afternoon, instead they are facing with some harmful virus inside their desktop computer.
TL;DR: Among species, differences in ozone uptake and response can be predicted from differences in the inherent leaf diffusive conductance, and for an equivalent dose within a single growing season, agricultural crops are the most sensitive to ozone.
Abstract: Published information about the effects of ozone on plants and ecosystems is synthesized into a conceptual model to explain the response of evergreen conifers, deciduous hardwoods and agricultural crops to ambient levels of ozone pollution. The effects of ozone on carbon balance and growth of individual plants can be quantified on the basis of concentration, external dose (concentration x duration of exposure), or uptake. For an equivalent dose within a single growing season, agricultural crops are the most sensitive to ozone, with hardwoods intermediate and conifers least sensitive. In contrast, all species display a similar decline in photosynthesis and growth in response to equivalent total uptake or uptake per leaf life span, with trees somewhat less sensitive than agricultural crops on a calendar time scale, but slightly more sensitive on a relative (leaf life span) time scale. Among species, differences in ozone uptake and response can be predicted from differences in the inherent leaf diffusive conductance.
TL;DR: An improved electrical impedance tomographic reconstruction algorithm is presented that is generally guaranteed to converge and provides significantly better reconstructions than any of the other methods.
Abstract: An improved electrical impedance tomographic reconstruction algorithm is presented that is generally guaranteed to converge. The algorithm is attractive for several reasons. A modified Newton?Raphson method varies a finite-element model of resistivities to fit a set of voltage measurements in a least-squared sense. Two procedures for calculating the Jacobian matrix are derived. One is standard, while the other is based on the compensation theorem. This second procedure is more efficient for computations, and just as accurate as the standard one. The inherent ill-conditioning in the approximate Hessian matrix of the linearized system is eliminated using the Marquardt method. Results from two-dimensional computer simulations are compared to four other reconstruction algorithms, which are based on methods proposed by other authors. The modified Newton?Raphson method provided significantly better reconstructions than any of the other methods. The algorithms compared are the perturbation, equipotential, iterative-equipotential, and the double-constraint methods. The modified Newton?Raphson method was found to be sensitive to measurement error, but future work in designing electrode-probing configurations is expected to reduce this sensitivity.
TL;DR: A handedness scale consisting of 13 questionnaire items selected from those of D. Raczkowski, J. Kalat, and R. Nebes was found to have high internal consistency for both males and females, high test-retest reliability, and a correlation of .83 with a behavioral measure of handedness.
Book•
01 Jan 1987TL;DR: The Gamma Camera: Basic Principles and Performance Characteristics and Digital Image Processing in Nuclear Medicine: Hybrid Imaging: SPECT/CT and PET/CT.
Abstract: 1 What is Nuclear Medicine? 2 Basic Atomic and Nuclear Physics 3 Modes of Radioactive Decay 4 Decay of Radioactivity 5 Radionuclide and Radiopharmaceutical Production 6 Interaction of Radiation with Matter 7 Radiation Detectors 8 Electronic Instrumentation for Radiation Detection Systems 9 Nuclear Counting Statistics 10 Pulse-Height Spectrometry 11 Problems in Radiation Detection and Measurement 12 Counting Systems 13 The Gamma Camera: Basic Principles 14 The Gamma Camera: Performance Characteristics 15 Image Quality in Nuclear Medicine 16 Tomographic Reconstruction in Nuclear Medicine 17 Single Photon Emission Computed Tomography 18 Positron Emission Tomography 19 Hybrid Imaging: SPECT/CT and PET/CT 20 Digital Image Processing in Nuclear Medicine 21 Tracer Kinetic Modeling 22 Internal Radiation Dosimetry 23 Radiation Safety and Health Physics Appendice A Appendice B Appendice C Appendice D Appendice E Appendice F Appendice G
TL;DR: The meaning of sustainability is strongly dependent on the context in which it is applied and on whether its use is based on a social, economic, or ecological perspective, and a useful definition must specify explicitly the context as well as the temporal and spatial scales being considered as mentioned in this paper.
Abstract: Sustainability is increasingly viewed as a desired goal of development and environmental management. This term has been used in numerous disciplines and in a variety of contexts, ranging from the concept of maximum sustainable yield in forestry and fisheries management to the vision of a sustainable society with a steady-state economy. The meaning of the term is strongly dependent on the context in which it is applied and on whether its use is based on a social, economic, or ecological perspective, Sustainability may be defined broadly or narrowly, but a useful definition must specify explicitly the context as well as the temporal and spatial scales being considered. Although societies differ in their conceptualizations of sustainability, indefinite human survival on a global scale requires certain basic support systems, which can be maintained only with a healthy environment and a stable human population. A clearer understanding of global sustainability and the development of appropriate indicators of the status of basic support systems would provide a useful framework for policy making.
TL;DR: In this article, the authors discuss the structure, physical properties, and implications of no-scale supergravity models and study in considerable detail all the basic ingredients that come to play in their structure, such as supersymmetry and supergravity.
Journal Article•
TL;DR: Inhibition of angiogenesis in the mouse initiated by either human or murine tumor cell lines was achieved whether vascular response was assessed 1 or 3 days after tumor cell inoculation, suggesting that antiangiogenesis activity was independent of the antiproliferative effects of IFNs.
Abstract: Interferons (IFNs) have established antitumor action; the mechanism underlying this effect is, however, not yet clear. To probe the possible contribution of inhibition of angiogenesis, we have assessed angiogenesis in the mouse initiated by either human or murine tumor cell lines. Whether test cells were inoculated in the dermis or tumor fragments were grafted onto the cornea, tumor-induced angiogenesis (TIA) was inhibited by IFNs. TIA was also inhibited by the potent IFN inducer polyriboinosinic-polyribocytidylic acid. The effect of IFN was species specific; human IFNs inhibited human tumors and mouse IFNs inhibited murine tumors. This effect suggested that in contrast to other angiogenesis inhibitors, IFNs modulated the signal for angiogenesis produced by the tumor cells. Tumor cells treated in vitro with homologous IFN were significantly (P less than 0.005) less competent to initiate angiogenesis than were untreated cells. Inhibition of angiogenesis was achieved whether vascular response was assessed 1 or 3 days after tumor cell inoculation, suggesting that antiangiogenesis activity was independent of the antiproliferative effects of IFNs. To further substantiate this, L1210 leukemia cells, resistant to the antiproliferative effects of IFNs, were treated with 500 units/ml IFN-beta. IFN had no effect on their proliferation, but in four separate experiments, L1210R cells were impaired in their ability to induce angiogenesis. Thus, inhibition of TIA by IFNs was species specific, occurred at least partly by modulation of the signal inducing angiogenesis, and was expressed in the absence of antiproliferative effects. IFNs also inhibited immunologically induced angiogenesis, whether initiated by allogeneic lymphocytes (LIA) or by the mouse's own T-cells in response to an exogenous antigen (sheep RBC). LIA was markedly suppressed by treatment of host mice with homologous IFN-beta. For example, mean vessel counts induced by allogeneic mouse lymphocytes were decreased from 22.8 +/- 1.4 (SE) to 12.5 +/- 0.8 (P less than 0.0001); mouse IFN-beta had no corresponding effect on xenogeneic human lymphocytes (mean vessel counts decreased to 21.7 +/- 2.6 from 22.7 +/- 2.0). Treatment with human IFN-alpha, -beta, or -gamma in vitro or host mice in vivo reduced the ability of inoculated human peripheral blood lymphocytes to initiate xenogeneic LIA. Inhibition of LIA required a lower dose and/or a shorter incubation period than that needed to modulate TIA. Treatment of the donor of the allogeneic spleen cells in vivo with murine IFN or inducers also resulted in lesser LIA.(ABSTRACT TRUNCATED AT 400 WORDS)
TL;DR: A complete interpreter for negation as failure in logic programming exists in theory, although it is pointed out that there are serious difficulties in building one that works well in practice.
Abstract: We define a semantics for negation as failure in logic programming. Our semantics may be viewed as a cross between the approaches of Clark [5] and Fitting [7]. As does [7], our semantics corresponds well with real PROLOG in the standard examples used in the literature to illustrate problems with [5]. Also, PROLOG and the common variants of it are sound but not complete for our semantics. Unlike [7], our semantics is constructive, in that the set of supported queries is recursively enumerable. Thus, a complete interpreter exists in theory, although we point out that there are serious difficulties in building one that works well in practice.
TL;DR: In this article, the authors made a capsule presentation of five major theoretical approaches to compliance research (Biomedical, Behavioral, Operant and Social Learning, Communication, Rational Decision, Health Belief and Reasoned Action, Self-Regulative Systems) and brief summaries made of their respective contributions and deficits.
TL;DR: In this article, the authors examined the life cycles of the 30-60 day atmospheric oscillation by compositing 30-day filtered NMC global wind analyses (250 mb and 850 mb) and outgoing longwave radiation (OLR) for the years 1979-84.
Abstract: Life cycles of the 30–60 day atmospheric oscillation were examined by compositing 30–60 day filtered NMC global wind analyses (250 mb and 850 mb) and outgoing longwave radiation (OLR) for the years 1979–84. Separate composite life cycles were constructed for the May–October and November–April seasons using empirical orthogonal function analysis of the large-scale divergent wind field (250 mb velocity potential) to define the oscillation's phase. Monte Carlo simulations were used to assess the statistical significance of the composite OLR and vector wind fields. Large-scale (wavenumber one) tropical divergent wind features propagate eastward around the globe throughout the seasonal cycle. The spatial relationships between these propagating circulation features and OLR are shown using sequences of composite maps. Good agreement exists between areas of upper-air divergence and areas of convection inferred from the OLR satellite data. Convection anomalies are smaller over tropical Africa and South Am...
TL;DR: Individual copying theory and family stress theory are reviewed to provide a theoretical foundation for assessing adolescent coping and the development and testing of an adolescent self-report coping inventory, Adolescent Coping Orientation for Problem Experiences (A-COPE) is presented.
TL;DR: This is the first report of the isolation of E. coli O157:H7 from food other than ground beef, and results indicate that the organism is not a rare contaminant of fresh meats and poultry.
Abstract: A total of 896 samples of retail fresh meats and poultry was assayed for Escherichia coli serogroup O157:H7 by a hydrophobic grid membrane filter-immunoblot procedure developed specifically to isolate the organism from foods The procedure involves several steps, including selective enrichment, filtration of enrichment culture through hydrophobic grid membrane filters, incubation of each filter on nitrocellulose paper on selective agar, preparation of an immunoblot (by using antiserum to E coli O157:H7 culture filtrate) of each nitrocellulose paper, selection from the filters of colonies which corresponded to immunopositive sites on blots, screening of isolates by a Biken test for precipitin lines from metabolites and antiserum to E coli O157:H7 culture filtrate, and confirmation of isolates as Vero cell cytotoxic E coli O157:H7 by biochemical, serological, and Vero cell cytotoxicity tests E coli O157:H7 was isolated from 6 (37%) of 164 beef, 4 (15%) of 264 pork, 4 (15%) of 263 poultry, and 4 (20%) of 205 lamb samples One of 14 pork samples and 5 of 17 beef samples contaminated with the organism were from Calgary, Alberta, Canada, grocery stores, whereas all other contaminated samples were from Madison, Wis, retail outlets This is the first report of the isolation of E coli O157:H7 from food other than ground beef, and results indicate that the organism is not a rare contaminant of fresh meats and poultry
TL;DR: The results indicate that retinopathy may be preventable but tends to resist arrest even in its incipient stages, before more than the first few aneurysms have appeared.
Abstract: To assess the extent to which the progression of diabetic retinopathy can be arrested by improved glycemic control, 35 normal dogs were randomly divided into a nondiabetic and three alloxan-induced diabetic groups prospectively identified according to glycemic control: poor control for 5 yr (PC), good control for 5 yr (GC), and poor control for 2.5 yr followed by good control for 2.5 yr (PGC). To achieve good control, insulin was given twice daily together with a measured diet so that hyperglycemia and glucosuria were mild and infrequent, and HbA1 was comparable to normal. Retinal capillary aneurysms and other lesions developed during 60 mo of poor control (group PC) and were inhibited if good control was begun promptly within 2 mo (group GC). In group PGC, retinopathy was absent or equivocal at 2.5 yr of poor control and, surprisingly, was found to develop subsequently despite good glycemic control. Retinopathy in group PGC was greater at autopsy than at 2.5 yr and was greater than in group GC. The results indicate that retinopathy may be preventable but tends to resist arrest even in its incipient stages, before more than the first few aneurysms have appeared.
TL;DR: This article found that adults with children at home report that they are less happy and less satisfied with their lives than other groups, and that they worry more and experience higher levels of anxiety and depression.
Abstract: Recent studies suggest that parenthood may have negative consequences for the psychological well-being of adults. Adults with children at home report that they are less happy and less satisfied with their lives than other groups. They also appear to worry more and to experience higher levels of anxiety and depression. The overall difference between parents and nonparents appears to be small, although it has increased during the past two decades. Differences between parents and nonparents stem from economic and time constraints, which in turn arise from general social trends such as the increase in women’s labor force participation and the increase in marital disruption and single parenthood. We expect these trends to continue in the near future, reducing the desire for children and increasing gender conflict over the division of parental obligations. Parental strain might be alleviated by some form of state-supported childcare or child allowance.