Showing papers by "University of Massachusetts Amherst published in 1978"

Introduction to formal language theory

Abstract: From the Publisher: Formal language theory was fist developed in the mid 1950's in an attempt to develop theories of natural language acquisition. It was soon realized that this theory (particularly the context-free portion) was quite relevant to the artificial languages that had originated in computer science. Since those days, the theory of formal languages has been developed extensively, and has several discernible trends, which include applications to the syntactic analysis of programming languages, program schemes, models of biological systems, and relationships with natural languages.

Efficient maximum likelihood decoding of linear block codes using a trellis

Abstract: It is shown that soft decision maximum likelihood decoding of any (n,k) linear block code over GF(q) can be accomplished using the Viterbi algorithm applied to a trellis with no more than q^{(n-k)} states. For cyclic codes, the trellis is periodic. When this technique is applied to the decoding of product codes, the number of states in the trellis can be much fewer than q^{n-k} . For a binary (n,n - 1) single parity check code, the Viterbi algorithm is equivalent to the Wagner decoding algorithm.

Organizational/Environmental Interchange: A Model of Boundary Spanning Activity

Abstract: A theoretical framework is developed for analyzing determinants and functions of activity at the boundaries of organizations. The process of boundary spanning, based on internal and external organizational factors, is conceptualized. A model of the organizational/environmental information interchange process suggests relationships between organizational, environmental, and individual aspects of boundary activity.

Visualization of the supramolecular architecture of chlorosomes (chlorobium type vesicles) in freeze-fractured cells of Chloroflexus aurantiacus

Abstract: Freeze-fracture electron microscopy has been used to investigate the size, form, distribution and supramolecular organization of chlorosomes (chlorobium type vesicles) in Chloroflexus aurantiacus J-10fl, a phototrophic, filamentous gliding bacterium. The chlorosomes, that appear tightly attached to the cytoplasmic membrane, have the form of flat, elongated sacs with rounded ends, and measure 106±24×32±10×12±2nm. They are randomly distributed, and in most instances their longitudinal axis makes an angle of 30–60° to the filament axis. Each chlorosome consists of a core and an approx. 2 nm thick envelope. The core is filled with rod-shaped elements (approx. 5.2 nm in diameter) made up of globular subunits with a periodicity of approx. 6 nm. The rod elements extend the full length of the chlorosome. The membrane-associated envelope layer is marked by extremely fine striations with a repeating distance of 2.5–3nm, while the envelope layer adjacent to the cytoplasm exhibits no discernable substructure. The margins of the vesicles are delineated by regularly spaced 7 nm particles.

The spontaneously diabetic Wistar rat (the "BB" rat). Studies prior to and during development of the overt syndrome.

Abstract: A longitudinal study of 51 weanlings from 5 litters of “BB” Wistar rats was undertaken to characterize the time course of the spontaneous diabetic syndrome. Nine rats developed overt diabetes. An abnormal glucose tolerance preceded the onset of the syndrome in 6 of these 9 rats. No other “clinical” or metabolic variable measured was predictive of the development of this syndrome. In these rats, the onset was remarkably abrupt, followed by rapid clinical deterioration with marked hyperglycaemia, glycosuria, ketonaemia and hypoinsulinaemia attained within 2 to 8 days. Pronounced insulitis was present in the early stages of the syndrome, resulting in complete B-cell destruction at the time of sacrifice at 7 to 40 days. Among the 42 littermates, 9 revealed sequential abnormalities in oral glucose tolerance tests performed at weekly intervals (to age 90–120 d) though remaining aglycosuric and maintaining normal fasting plasma glucose levels. In 7 of these rats, a milder form of the same islet inflammatory lesion seen in the overtly diabetic animals was present. Thus the new features identified are: 1) a time course of evolution from normoglycaemia to overt diabetes telescoped into a period of days, and 2) a “chemical” stage or form with an insulitis similar to that found in the early stages of overt diabetes.

Part Two: The role of constitutional factors, diet, and infectious disease in the etiology of porotic hyperostosis and periosteal reactions in prehistoric infants and children.

Abstract: A model of analysis incorporating methodological improvements and epidemiological refinements has been employed to investigate the etiology of porotic hyperostosis and periosteal reactions in infants and children from the Libben Site, a Late Woodland ossuary and occupation site from Ottawa County, Ohio. Results of the age‐specific intrapopulational analysis of porotic hyperostosis demonstrate that the skeletal lesion strongly fits the age‐specific distribution of hypochromic microcytic iron‐deficiency anemia in infants and children. The data indicate that the lesion is a response to nutritional stress. Similarly, our findings show that the age‐specific distribution of periosteal reactions strongly coincides with, and appears to be a response to, infectious disease as it occurs in infants and children. More importantly, survivorship and growth data indicate that porotic hyperostosis and periosteal reactions are strongly associated with patterns of infant and child morbidity and mortality, and ther...

Work Satisfaction and Age: Some Evidence for the ‘Job Change’ Hypothesis

Abstract: Previous research on work satisfaction has consistently shown that older people are more satisfied with their jobs than younger people. The present paper addresses three possible explanations for this tendency: (1) the "1now generation" of workers subscribes to a set of post-material values that contradict the demands of the industrial system and cause greater work discontent; (2) the standards of the old are systematically eroded by their years in the system, such that they learn to be satisfied with less; and (3) older workers simply have better jobs. A decisive choice among these hypotheses cannot be made without longitudinal data; nonetheless, the bulk of the evidence presented here (for economically active, salaried white males, drawn from the University of Michigan's 1972-73 Quality of Employment survey) clearly favors the last hypothesis. The academic literature on job satisfaction encompasses something in excess of 3000 independent studies (Campbell et al.; Kahn). Much of the existing research has focused on one of three basic topics: the sheer amount of satisfaction; the relationship between satisfaction and productivity; and the relationship between satisfaction and status, occupation, or social class. Concerning the first, the near-unanimous finding is that there is relatively little outright discontent; most people say they are "pretty satisfied" with their work (Kahn, 169).1 There is much less consensus on the second. Kahn's review, for example, concludes that "satisfaction is related to productivity in some circumstances and not in others, and that these circumstances have yet to be defined" (193). As for the link to social class, Jencks and associates have argued that the correlations between work satisfaction and various measures of social status "are surprisingly weak" (247). Prior studies, they suggest, simply "stress the importance of small differences between occupations." In contrast to the voluminous literature on work satisfaction and SES, there has not been much analysis of the relation between satisfaction

Limit theorems for sums of dependent random variables occurring in statistical mechanics

Abstract: We study the asymptotic behavior of partial sums S nfor certain triangular arrays of dependent, identically distributed random variables which arise naturally in statistical mechanics. A typical result is that under appropriate assumptions there exist a real number m, a positive real number λ, and a positive integer k so that (S n−nm)/n1−1/2k converges weakly to a random variable with density proportional to exp(−λ¦s¦ 2k/(2k)!). We explain the relation of these results to topics in Gaussian quadrature, to the theory of moment spaces, and to critical phenomena in physical systems.

Objective Personality Assessment

Abstract: This chapter aims to provide a broad, empirically-based sketch of normal personality and its changes throughout adulthood While it is not intended as a cookbook treatment of the application of objective tests to geriatric populations, it does attempt to make specific links between normal personality and clinical gerontology One example of this is provided by a consideration of the male midlife crisis, that putatively universal, normative, developmental phase which at the same time can be considered a pre-geriatric clinical condition Similarly, our theoretical discussion of openness to experience—a personality dimension relevant to the call for more humanistic approaches to aging—is supplemented by presentation of an instrument which may prove a useable operationalization of it Objective personality assessment has a long and controversial past, but evidence and arguments presented here suggest that its careful use can make a substantial contribution to the field

Some remarks on the paper of Callias

Abstract: This paper discusses the topological setting of the preceding paper by Callias. In particular, an alternate way of deriving his results is outlined.

Control of Distributed Processes

Abstract: Cost-effective control of distributed computing systems requires practical models for reassigning program modules among the processors in real time.

Critical Load Factors in Two-Processor Distributed Systems

Abstract: In a two-processor distributed computer network, prior research showed that a maximum flow algorithm can be used to find optimal program-module-to-processor assignments to maximize the performance of distributed programs. This paper examines the sequence of optimal assignments found as the load on one processor is held fixed and the load on the other is varied. For every program module M there exists a critical load factor fM such that when the load on the processor with variable load is below fM, M is assigned to that processor by an optimal assignment, and is otherwise assigned to the other processor. This characteristic opens the possibility of doing optimal dynamic assignments in real-time.

Colorimetry — methodology and applications∗

Abstract: Color and appearance, those nebulous aspects of food acceptability which are taken for granted by most consumers, are coming under increasingly severe scrutiny. For this reason, it is essential that an adequate knowledge base for measurement be available to those working in the field. This base must be grounded upon the fact that color is a sensory phenomenon, and its measurement must include the physical, psychological, and physiological aspects. That is, measurement must involve tristimulus colorimetry, whether obtained by spectrophotometric or colorimetric techniques. It is the object of this article to review the general area of tristimulus colorimetry along with the techniques required for measurement. It is essential to include a section on the manipulation of data as well, since colorimetric data is often misused. Further treatment will be given to object-light interactions and how these affect not only measurement but sample perception, since manipulation of the physical parameters of the sample can affect the total appearance and color. Instruments and their usage will be reviewed so that decisions may be made on the correct instrument for a particular measuring system. In addition, a section will be devoted to on-line color measurement which may facilitate continuous processes. A final section of this article will deal with some advances in data manipulation and the development of new scales for color measurement. Fundamental colorimetric theory is essential in this area for proper usage. It is the aim of this paper to integrate theory with application in order to facilitate optimization of both the color of food and its measurement.

The Statistics of Curie-Weiss Models

Abstract: LetSn denote the random total magnetization of ann-site Curie-Weiss model, a collection ofn (spin) random variables with an equal interaction of strength 1/n between each pair of spins. The asymptotic behavior for largen of the probability distribution ofSn is analyzed and related to the well-known (mean-field) thermodynamic properties of these models. One particular result is that at a type-k critical point (Sn-nm)/n1−1/2k has a limiting distribution with density proportional to exp[-λs2k/(2k)!], wherem is the mean magnetization per site and A is a positive critical parameter with a universal upper bound. Another result describes the asymptotic behavior relevant to metastability.

Thermodynamic Characterization of Conformational States of Biological Macromolecules using Differential Scanning Calorimetry

Abstract: (1978). Thermodynamic Characterization of Conformational States of Biological Macromolecules using Differential Scanning Calorimetry. CRC Critical Reviews in Biochemistry: Vol. 5, No. 2, pp. 85-124.

Histological Enamel Indicator of Childhood Stress in Prehistoric Skeletal Samples

Abstract: Although previous paleopathological studies have used distur- bances in enamel formation as indicators of childhood stress, the full potential of this technique has not been realized. This paper presents a test case which demonstrates that the frequency of disturbed enamel formation Le., Wilson bands) is associated with other stress indicators (i.e,, probability of dying and infectious lesions) in three prehistoric skeletal samples representing the Middle Woodland (1 0.3%), Mississippian Acculturated Late Woodland (21.4!%), and the Middle Mississippian (40.0X?. Additionally, the mean ages at death of individ- uals with at least one Wilson band are lower than those without bands. These results suggest that Wilson bands are an indicator of the relative proportion of individuals who are high susceptibles in prehistoric populations. The data also corroborate the hypothesis that t he adoption of maize agriculture in the prehistoric American Midwest is associated with increased stress. Previous research suggests that distur- bances in enamel prism formation such as enamel hypoplasia and pathological bands are associated with episodes of morbidity and nutritional disturbances in human popula- tions (Kreshover, '40, '60; Massler et al., '41; Watson et al., '64). Because of this relation- ship with disease and chronological specif- icity, disturbed enamel formation has been used in paleopathology to estimate environ- mental stress and disease experience (Falin, '61; Molnar and Ward, '75; Sognnaes, '55, '56). General application of this methodology to paleopathological problems has been hindered by t,he absence of consistent criteria for defin- ing enamel prism formation. Rose ('77) dem- onstrates that details of enamel prism mor- phology observed in ground thin sections of human enamel with the light microscope can consistently identify one type of disturbed enamel formation. These particular pathologi- cal bands were first reported by Wilson and Schroff ('701. In order to avoid the erroneous implications of the term pathological, they will be called Wilson bands in this paper. Ob- servation with the scanning electron micro-

Cytoplasmic 17 beta-[3H]estradiol binding in rat adipose tissues.

Abstract: Ovarian hormones, particularly 17 beta-estradiol, have important effects on body fat levels in rats, but it is not known whether 17 beta-estradiol can act directly on various fat depots to affect adiposity or whether these effects are entirely indirect (e.g. via food intake, exercise, or various metabolic actions). We have found high affinity, estrogen-specific macromolecular binding of 17 beta-[3H]estradiol in the cytoplasmic fraction of adipose tissues from ovariectomized rats. Saturation analysis indicates a Kd of 7.4 X 10(-10) M, and binding is inhibited by unlabeled 17 beta-estradiol or 11 beta-methoxy-17-ethynyl-1,3,5(10)-triene-3,17beta-diol (R2858) but not by progesterone, 5 alpha-dihydrotestosterone, or cortisol. 17 beta-[3H]Estradiol binding is virtually abolished by incubation with pronase but not with DNase or RNase, indicating that the binding macromolecule is probably a protein. Binding is seen in all adipose tissues studied, including abdominal, sc, and brown fat. Binding site concentration is highest in parametrial fat pads, followed by retroperitoneal, brown, omental, and inguinal depots. Binding is also seen in the cytoplasmic fraction of isolated parametrial adipocytes. These data indicate that the various adipose tissues might be estrogen target tissues in rats. Therefore, it is possible that estrogenic effects on body weight and composition could be mediated in part by direct estrogen action on adipose tissues.

A new aeolian sand trap design

Abstract: A vertical rod sand trap has been constructed to acquire a volumetric measure of wind-blown sand. The design is simple, construction cost is minimal, and collection efficiency is quite high. This device can be used effectively for short-term monitoring of aeolian transport.

Mechanical interpretation of compressive stress‐strain relationships of solid foods

Abstract: True compressive stress-strain relationships of various solid foods have been demonstrated in a three-dimensional display that has included the tests true strain histories. The shapes of the stress-strain curves and complementary relaxation and compressiblity data indicated the existence of two antagonistic mechanisms which regulated the stress levels. These were internal fractures which tended to decrease the mechanical strength of the deformed specimens and structural compaction that had the tendency to increase it. It has also been demonstrated that the true stresses could be influenced by the specimen dimensions as well as by the strain rate.

Life Satisfaction and Religion: A Reanalysis

Abstract: Findings by Campbell et al. in The Quality of American Life suggesting that religious people tend to be somewhat less satisfied with their lives than the nonreligious are reexamined in this paper. Using the same data source and variables it is shown that their interpretation is in error, and that to the contrary, religion functions more as a resource than as compensation. In recent years the quality of life in American society has received a good deal of attention. But for the most part studies of life satisfaction and happiness have relied either on local samples or the few subjective items found in such national samples as the National Opinion Research Center's general social surveys and the Survey Research Center's national election studies. Fortunately, however, the recent Quality of American Life Survey conducted by the Survey Research Center has made possible much more complete analyses of life satisfaction in the United States. The first body of findings to be reported from this survey was The Quality of American Life (Campbell et al.). Campbell et al. treated a great range of issues, but my primary interest is with their findings about the relationship between religiosity and life satisfaction. A number of these findings contradicted earlier works that had shown religious persons to be more satisfied with their lives than is the tendency for nonreligious people. In this research note I report a reanalysis of their results in order to examine more fully the empirical relationship among religiosity and feelings of satisfaction. Research into Religion and Quality of Life

Psychographic Segmentation of Tourists

Abstract: Life-style data are used to profile the tourists to Massachusetts. Only slight differences are found by season and by year. The tourism market is further segment ed on the basis of purpose of trip and type of destination. Psychographic and demographic differences in segments are noted and advertising strategies suggested for the different target markets.

Visual generalist with visual specialist phytophagous insects: host selection behaviour and application to management

Abstract: Our findings suggest that Hoplocampa testudinea adults (apparently monophagous) and Rhagoletis pomonella flies (oligophagous) are more specific in orientation to hue and/or form of feeding, mating, or oviposition sites on a common host (apple) than are Lygus lineolaris adults (polyphagous) on apple. We speculate that subject to varying influence by host plant chemical stimuli, many monophagous – oligophagous insects may tend to be visual specialists in comparison with polyphagous insects, especially those polyphagous species whose preferred feeding, mating, or oviposition sites within an individual plant are of diverse physical characteristics. They may tend more toward being visual generalists. Visual traps incorporating the synthetic equivalents of comparatively specific host plant visual stimuli should prove useful in monitoring and possibly even directly controlling a number of monophagous-oligophagous insects on crops. RESUME INSECTES PHYTOPHAGES GENERALISTES VISUELS ET SPECIALISTES VISUELS: COMPORTEMENT DE CHOIX DE LA PLANTE-HOTE ETAPPLICATION DANS LA LUTTE On montre que les adultes de Hoplocampa testudinea (apparemment monophages) et de Rhagoletis pomonella (oligophages) sont plus positivement specifiques visuellement dans leur orientation suivant la teinte et/ou la forme de leurs lieux d'alimentation, de copulation et de ponte sur un hote commun (le pommier) que les adultes de Lygus lineolaris (polyphages) sur le pommier. On emet l'hypothese que de nombreux insectes monophages-oligophages peuvent avoir tendance a etre des specialistes visuels si on les compare aux insectes polyphages, en particulier aux especes polyphages dont les lieux favoris d'alimentation, de copulation et de ponte ont des caracteristiques physiques diverses. Il se peut qu'ils aient plutot tendance a etre des generalistes visuels. Des pieges visuels incorporant les equivalents synthetiques de stimuli visuels relativement specifiques de la plante-hote seraient utiles pour surveiller et eventuellement detruire un certain nombre d'insectes monophages-oligophages dans les cultures.

X-ray and optical studies of the morphology of polymer blends

Abstract: Blends may be made of pairs of polymers where neither, one, or both components are crystalline. The state of compatibility for such blends may be deduced by x-ray and light scattering. A survey of recent studies in this laboratory of several binary blends of crystalline and amorphous polymers is presented.

Sex differences in the multiple-dose streptozotocin model of diabetes.

Abstract: The hyperglycemic response to multiple low-dose SZ injections was measured in castrated and non-castrated male and female mice with or without testosterone treatment. On the 10th day of the experiment, control males had plasma glucose concentrations that were significantly higher than those of control females. Castration of males decreased the hyperglycemic response, while testosterone treatment restored it. The glucose concentrations in castrated females were significantly greater than control females, but not different from castrated males. Testosterone administration to castrated or noncastrated females increased the hyperglycemic response to that seen in control males and in testosterone-treated castrated males. Thus, castration negates the sex difference in the hyperglycemic response to the multiple low-dose SZ injections. Testosterone enhances the hyperglycemic response in castrated or non-castrated females, and in castrated males.