Showing papers by "University of Wisconsin-Madison published in 1978"

On a measure of lack of fit in time series models

Abstract: SUMMARY The overall test for lack of fit in autoregressive-moving average models proposed by Box & Pierce (1970) is considered. It is shown that a substantially improved approximation results from a simple modification of this test. Some consideration is given to the power of such tests and their robustness when the innovations are nonnormal. Similar modifications in the overall tests used for transfer function-noise models are proposed.

A survey of interstellar H I from L-alpha absorption measurements. II

Abstract: The Copernicus satellite surveyed the spectral region near L alpha to obtain column densities of interstellar HI toward 100 stars. The distance to 10 stars exceeds 2 kpc and 34 stars lie beyond 1 kpc. Stars with color excess E(B-V) up to 0.5 mag are observed. The value of the mean ratio of total neutral hydrogen to color excess was found to equal 5.8 x 10 to the 21st power atoms per (sq cm x mag). For stars with accurate E(B-V), the deviations from this mean are generally less than a factor of 1.5. A notable exception is the dark cloud star, rho Oph. A reduction in visual reddening efficiency for the grains that are larger than normal in the rho Oph dark cloud probably explains this result. The conversion of atomic hydrogen into molecular form in dense clouds was observed in the gas to E(B-V) correlation plots. The best estimate for the mean total gas density for clouds and the intercloud medium, as a whole, in the solar neighborhood and in the plane of the galaxy is 1.15 atoms per cu. cm; those for the atomic gas and molecular gas alone are 0.86 atoms per cu cm and 0.143 molecules per cu cm respectively. For the intercloud medium, where molecular hydrogen is a negligible fraction of the total gas, atomic gas density was found to equal 0.16 atoms per cu cm with a Gaussian scale height perpendicular to the plane of about 350 pc, as derived from high latitude stars.

Thermodynamic analysis of ion effects on the binding and conformational equilibria of proteins and nucleic acids: the roles of ion association or release, screening, and ion effects on water activity.

Abstract: The purpose of this review is to examine the various effects of low- molecular-weight electrolytes on the associations and interactions of proteins and nucleic acids. Our primary interest is in general electrostatic effects, rather than chemical effects (specific interactions) of particular ions (e.g. transition metals, protons). We consider those interactions in which a variation in salt concentration has a significant effect on the macromolecular equilibrium, and analyse the effects of salt in these situations in terms of (i) direct participation of ions in the biopolymer reaction, (ii) Debye—Huckel screening by salt ions of the charge interactions on the biopolymers, and (iii) the reduction in water activity brought about at high salt concentrations.

Factors affecting response rates to mailed questionnaires: A quantitative analysis of the published literature.

Abstract: Two hundred fourteen manipulations of the independent variables in 98 mailed questionnaire response rate experiments were treated as respondents to a survey, yielding a mean final response rate of 60.6% with slightly over two contacts. The number of contacts and the judged salience to the respondent were found to explain 51% of the variance in final response. Government organization sponsorship, the type of population, the length of the questionnaire, questions concerning other individuals, the use of a special class of mail or telephone on the third contact, and the use of metered or franked mail on the outer envelope affected final response independent of contacts and salience. A causal model of the final response rate, including initial response, explaining 90% of the variance, and a regression equation predicting final response rates are presented to show that high response rates are achievable by manipulating the costs of responding and the perceived importance of both the research and the individual response.

Influence of culture parameters on lignin metabolism by Phanerochaete chrysosporium

Abstract: Culture parameters influencing metabolism of synthetic14C-lignins to14CO2 in defined media have been studied in shallow batch cultures of the ligninolytic wood-destroying HymenomycetePhanerochaete chrysosporium Burds. Study of the effect of O2 concentration in the gas phase above non-agitated cultures indicated essentially complete absence of attack on the lignin polymer at 5% O2 in N2, and a 2- to 3-fold enhancement by 100% O2 as compared to air (21% O2). Agitation of the cultures resulting in the formation of mycelial pellets greatly suppressed lignin decomposition. The optimum culture pH for lignin decomposition was 4 to 4.5, with marked suppression above 5.5 and below 3.5. The source of nutrient nitrogen (NO 3 − , NH 4 + , amino acids) had little influence on lignin decomposition, but the concentration of nitrogen was critical; decomposition at 24 mM was only 25–35% of that at 2.4 mM N. Thiamine was the only vitamin required for growth and lignin decomposition. Under the optimum conditions developed, decomposition of 5 mg of synthetic lignin was accompanied by utilization of approximately 100 mg of glucose. The influence of the various culture parameters was analogous for metabolism of synthetic lignin labeled in the ring-,side chain-, and methoxyl carbon atoms.

Consumer Socialization: A Theoretical and Empirical Analysis:

Abstract: The results of a large-scale study of adolescent consumer socialization are presented. A general conceptual framework of socialization is outlined to serve as a blueprint for discussing variables a...

An Attempted Integration of the Literature on the Export Behavior of Firms

Abstract: Forty-three studies on the export behavior of firms involving eleven countries were assembled. (The author believes that they constitute nearly all of the available literature on the subject.) An attempt was made to integrate them into a more-or-less meaningful whole that both yields interesting implications and provides a useful background guide for future research on the subject.

Design of liposomes for enhanced local release of drugs by hyperthermia

Abstract: Liposomes can be designed to release an entrapped drug preferentially at temperatures attainable by mild local hyperthermia. In a test system in vitro, protein synthesis by Escherichia coli is inhibited and killing of the cells is enhanced by heating neomycin-containing liposomes to their phase transition temperature to maximize drug release. In the presence of serum the ratio of release at 44 degrees C to that at 37 degrees C can be made greater than 100:1, suggesting possible applications in the treatment of tumors or local infection.

Perturbation analysis of fluxon dynamics

Abstract: A two-stage scheme is presented to study structural perturbations of the sine-Gordon equation. Although the method is based upon the inverse scattering transform, detailed knowledge of this technical apparatus is not necessary in order to effect the calculations. In the first stage, slow modulations of speeds and positions for the soliton components are computed. The radiation resulting from the acceleration of the solitons is then calculated as a first-order correction through an easily constructed radiative Green's function. The method is exemplified by using it to study several outstanding problems that arise in applications of the Josephson transmission line. In particular we consider: (i) the pinning of flux quanta by microshorts, (ii) the quantum flux shuttle, (iii) annihilation conditions for fluxon-antifluxon collisions, (iv) breather decay, and (v) radiation from a moving fluxon.

Periodic solutions of hamiltonian systems

Abstract: : The existence of periodic solutions of Hamiltonian systems of ordinary differential equations is proved in various settings. A case in which energy is prescribed is treated in Section 1. Both free and forced vibration problems, where the period is fixed, are studied in Section 2. The proofs involve finite dimensional approximation arguments, variational methods, and appropriate estimates. (Author)

Environmental context and human memory

Abstract: Five experiments examined the effects of environmental context on recall and recognition. In Experiment 1, variability of input environments produced higher free recall performance than unchanged input environments. Experiment 2 showed improvements in cued recall when storage and test contexts matched, using a paradigm that unconfounded the variables of context mismatching and context change. In Experiment 3, recall of categories and recall of words within a category were better for same-context than different-context recall. In Experiment 4, subjects given identical input conditions showed strong effects of environmental context when given a free recall test, yet showed no main effects of context on a recognition test. The absence of an environmental context effect on recognition was replicated in Experiment 5, using a cued recognition task to control the semantic encodings of test words. In the discussion of these experiments, environmental context is compared with other types of context, and an attempt is made to identify the memory processes influenced by environmental context.

Morphological factors influencing transepithelial permeability: a model for the resistance of the zonula occludens.

Abstract: Epithelial cells are joined at their apical surfaces byzonulae occludentes. Claude and Goodenough (1973) demonstrated a correlation between the structure of thezonula occludens as seen in freeze-fracture preparations and the passive electrical permeability of several simple epithelia. In epithelia with high transepithelial resistance, thezonula occludens consisted of many strands. In epithelia with low transepithelial resistance thezonula occludens was much reduced, sometimes consisting of only one strand. Evidence is reviewed here that indicates that in a number of simple epithelia the structure of thezonula occludens is largely responsible for the magnitude of transepithelial conductance. An equation is derived relating transepithelial junctional resistance to the number of junctional strands:R=R min p −n whereR is the transepithelial resistance of thezonula occludens,R min is the minimum resistance of the junction (as when there areno strands in the zonula occludens),p is the probability a given strand is “open” andn is the number of strands in the junction. Using published experimental values ofR andn for different epithelia, the calculated value ofp was found to be as high as 0.4, which suggests that the strands in thezonula occludens are remarkably labile. Other morphological parameters relevant to transepithelial permeability are also considered, such as the width and depth of the intercellular spaces, and the size of the epithelial cells themselves.

Speech-discrimination scores modeled as a binomial variable.

Abstract: Many studies have reported variability data for tests of speech discrimination, and the disparate results of these studies have not been given a simple explanation. Arguments over the relative meri...

Improper Priors, Spline Smoothing and the Problem of Guarding Against Model Errors in Regression

Abstract: SUMMARY Spline and generalized spline smoothing is shown to be equivalent to Bayesian estimation with a partially improper prior. This result supports the idea that spline smoothing is a natural solution to the regression problem when one is given a set of regression functions but one also wants to hedge against the possibility that the true model is not exactly in the span of the given regression functions. A natural measure of the deviation of the true model from the span of the regression functions comes out of the spline theory in a natural way. An appropriate value of this measure can be estimated from the data and used to constrain the estimated model to have the estimated deviation. Some convergence results and computational tricks are also discussed.

Endangered Species and Uncertainty: The Economics of a Safe Minimum Standard

Abstract: Species extinction irreversibly narrows the reservoir of potential resources. The future repercussions of this narrowing are uncertain. This paper develops the safe minimum standard (SMS) approach to public decisions involving endangered species. The SMS approach is based on game theory and calls for avoidance of extinction unless the social costs are unacceptably large. The level at which costs become excessive is a matter of intergenerational distribution. The paper also explores important linkages between the SMS approach and recent literature on preservation of natural environments.

Biochemical characterisation of stages of hepatocarcinogenesis after a single dose of diethylnitrosamine

Abstract: CURRENT understanding of the pathogenesis of neoplasia rests principally on the demonstration1–3 that the induction of carcinomas of mouse skin by hydrocarbons can be separated into at least two stages. There is evidence of similar stages in the natural history of carcinogenesis of nonepidermal tissues4–7. For example, Peraino et al.6 have shown that short term feeding of acetylaminofluorene to rats followed by a long term diet containing 0.05% phenobarbital results in 100% incidence of hepatomas, whereas animals receiving acetylaminofluorene and no phenobarbital developed 10 times fewer hepatocarcinomas. Peraino's procedure and that of Kitagawa et al.7, who fed rats azo dye followed by phenobarbital, required that the carcinogen be fed to the rats for 3–8 weeks. On the other hand, Scherer and Emmelot8 have shown that a single large dose of diethylnitrosamine given to rats within 24 h of partial hepatectomy can induce hepatocellular carcinomas, whereas low doses (< 30 mg kg−1), given in the same way, give rise only to small foci of cells deficient in ATPase, comparable with those described earlier9,10. Further, Solt and Farber11 have reported that a single dose of diethylnitrosamine followed by acetylaminofluorene and partial hepatectomy rapidly produces foci containing γ-glutamyl transpeptidase, in contrast to the situation in normal liver which exhibits no histochemical activity of that enzyme. By combining the procedure of Scherer and Emmelot8 with that of Peraino et al.6, we have been able to distinguish clearly between two stages in the genesis of liver cancer in rats.

Anxiety reduction following exercise and meditation

Abstract: The purpose of this investigation was to compare the influence of acute physical activity and meditation (“noncultic”)on state anxiety. Seventy-five adult male volunteers served as Ss with 25 Ss randomly assigned to either an exercise, meditation, or control group. Physical activity was performed at 70% of self-imposed maximal exercise heart rate for 20 minutes by Ss in the exercise group; Ss assigned to the meditation group practiced Benson's Relaxation Response for 20 minutes; and Ss in the control group simply rested quietly in a “Lazyboy” chair for 20 minutes. State anxiety was measured with the Spielberger Scale, and it was assessed (1)prior to, (2)immediately following, and (3)10 minutes following each treatment. Oxygen consumption, heart rate, skin temperature, and blood pressure were also measured as confirmatory variables under selected conditions. The data were analyzed by means of a two-way repeated measures ANOVA, and this analysis revealed that a significant reduction in anxiety occurred for each treatment. This held for both those Ss falling within the normal range for state anxiety and those Ss regarded as high-anxious. It was also noted that none of the physiological variables differed significantly following the control and meditation treatments. The present evidence suggests that acute physical activity, noncultic meditation, and a quiet rest session are equally effective in reducing state anxiety.

Large-scale Tropical Atlantic surface circulation patterns associated with Subsaharan weather anomalies

Abstract: Identification is made of the Tropical Atlantic (30° N–30° S) surface atmospheric and oceanic patterns of a data set composited for 5 years which were very dry in Subsaharan West Africa (11–20°N). Patterns for a counterpart wet composite data set are also presented. Sixty-year (1911–70) average fields constitute a background reference. For the rainy season (July–September) of the dry composite, the Tropical Atlantic near-equatorial pressure trough, kinematic axis separating Northern and Southern Hemisphere Trades, and zone of maximum sea surface temperature (SST) are located 200–300 km south of their 60-year average positions. Concurrently, the North Atlantic subtropical high (NAH) extends further equatorward than average, although its centre lies up to 150 km north of its mean latitude. Both Northeast and Southeast Trades are stronger than average, and negative and positive SST anomalies occur north and south of approximately 10° N, respectively. Some of these anomalies evolved during the preceding January-June, which offers encouragement that Subsaharan droughts may be predictable 3 to 6 months in advance. Patterns for July–September of the wet composite contain fewer and less pronounced anomalies. The NAH is centred 100–150 km further north and extends less equatorward than average, the kinematic axis lies 100–150 km north of its mean latitude, and the Trades are weak in many areas. Except for the northward displacement of the NAH centre, these anomalies are opposite to those for the dry composite July–September. The wet composite July–September anomalies did not evolve during preceding seasons. DOI: 10.1111/j.2153-3490.1978.tb00839.x

Tissue mimicking materials for ultrasound phantoms

Abstract: Up until now, no material has been found whose attenuation and speed of sound properties not only mimic those of human soft tissue, but are controllable in magnitude. We have discovered such a material in the form of water-based pharmaceutical gels containing uniform distributions of graphite powder and known concentrations of alcohol. The magnitude of the attenuation coefficient can be controlled easily between 0.2 and 1.5 dB/cm at 1 MHz, by varying the concentration of graphite. These attenuation coefficients are nearly proportional to the frequency. The speed of sound varies between 1520 and 1650 m/s at room temperature, depending primarily upon the concentration of alcohol. Bacterial invasion has been prevented by sterilization procedures and the introduction of appropriate preservatives. The ultrasonic properties exhibit temporal stability and change little over the range of room temperatures.

Satellite cells are mitotically quiescent in mature mouse muscle: An EM and radioautographic study

Abstract: Normal adult mouse tibialis anterior muscles were perfused continuously with 3H-thymidine for nine days. Quantitation of the satellite cell population in these muscles reveals that not only is the frequency of satellite cell nuclei low, but that those present are mitotically quiescent.

On a Class of Polynomials Connected with the Korteweg-De Vries Equation

Abstract: A new and simpler construction of the family of rational solutions of the Korteweg-deVries equation is given. This construction is related to a factorization of the Sturm-Liouville operators into first order operators and a new deformation problem for the latter. In the final section the spectral representation for the corresponding complex potentials is discussed.

Integration of featural information in speech perception.

Abstract: A model for the identification of speech sounds is proposed that assumes that (a) the acoustic cues are perceived independently, (b) feature evaluation provides information about the degree to which each quality is present in the speech sound, (c) each speech sound is denned by a propositional prototype in longterm memory that determines how the featural information is integrated, and (d) the speech sound is identified on the basis of the relative degree to which it matches the various alternative prototypes. The model was supported by the results of an experiment in which subjects identified stop-consonant-vowel syllables that were factorially generated by independently varying acoustic cues for voicing and for place of articulation. This experiment also replicated previous findings of changes in the identification boundary of one acoustic dimension as a function of the level of another dimension. These results have previously been interpreted as evidence for the interaction of the perceptions of the acoustic features themselves. In contrast, the present model provides a good description of the data, including these boundary changes, while still maintaining complete noninteraction at the feature evaluation stage of processing. Although considerable progress has been made in the field of speech perception in recent years, there is still much that is unknown about the details of how speech sounds are perceived and discriminated. In particular, while there has been considerable success in isolating the dimensions of acoustic information that are important in perceiving and identifying speech sounds, very little is known about how the information from the various acoustic dimensions is put together in order to actually accomplish identification. The present article proposes and tests a model of these fundamental integration processes that take place during speech perception. Much of the study of features in speech has focused on the stop consonants of English. The stop consonants are a set of speech sounds