Showing papers by "University of Massachusetts Amherst published in 1992"

A Comparison of the Theory of Planned Behavior and the Theory of Reasoned Action

Abstract: Research in social psychology has extensively referenced and used Fishbein and Ajzen's theory of reasoned action to predict and understand motivational influences on behavior Recently Ajzen has proposed an extension of the theory by including perceptions of behavioral control as an additional predictor of intentions and behavior. The present research compared Ajzen's theory of planned behavior with the theory of reasoned action for 10 behaviors chosen to represent a range with respect to control over performing the behavior. he results indicate that inclusion of perceived behavioral control enhances the prediction of behavioral intention and behavior Consistent with the theory of planned behavior, the effects of perceived behavioral control on a target behavior are most vivid when the behavior presents some problem with respect to control.

Application of the Theory of Planned Behavior to Leisure Choice.

Abstract: The theory of planned behavior (Ajzen, 1985, 1987) is used to predict leisure intentions and behavior. College students completed a questionnaire that measured involvement, moods, attitudes, subjec...

Information filtering and information retrieval: two sides of the same coin?

Abstract: Information filtering systems are designed for unstructured or semistructured data, as opposed to database applications, which use very structured data. The systems also deal primarily with textual information, but they may also entail images, voice, video or other data types that are part of multimedia information systems. Information filtering systems also involve a large amount of data and streams of incoming data, whether broadcast from a remote source or sent directly by other sources. Filtering is based on descriptions of individual or group information preferences, or profiles, that typically represent long-term interests. Filtering also implies removal of data from an incoming stream rather than finding data in the stream; users see only the data that is extracted. Models of information retrieval and filtering, and lessons for filtering from retrieval research are presented.

Dynamics of the Standard Model

Abstract: Preface Inputs to the standard model Interactions of the standard model Symmetries and anomalies Introduction to effective Lagrangians Leptons Very low energy QCD - Pions and photons Introducing kaons and etas Kaons and the S=1 interaction Kaon mixing and CP violation The large N expansion Phenomenological models Baryon properties Hadron spectroscopy Weak interactions of heavy quarks The Higgs boson The electroweak gauge bosons Appendices References Index.

Confidence interval estimation of interaction.

Abstract: Relative excess risk due to interaction, the proportion of disease among those with both exposures that is attributable to their interaction, and the synergy index have been proposed as measures of interaction in epidemiologic studies. This paper presents the methodology for obtaining confidence int

Muscle function after exercise-induced muscle damage and rapid adaptation

Abstract: This brief review focuses on the time course of changes in muscle function and other correlates of muscle damage following maximal effort eccentric actions of the forearm flexor muscles. Data on 109 subjects are presented to describe an accurate time course of these changes and attempt to establish relationships among the measures. Peak soreness is experienced 2-3 d postexercise while peak swelling occurs 5 d postexercise. Maximal strength and the ability to fully flex the arm show the greatest decrements immediately after exercise with a linear restoration of these functions over the next 10 d. Blood creatine kinase (CK) levels increase precipitously at 2 d after exercise which is also the time when spontaneous muscle shortening is most pronounced. Whether the similarity in the time courses of some of these responses implies that they are caused by similar factors remains to be determined. Performance of one bout of eccentric exercise produces an adaptation such that the muscle is more resistant to damage from a subsequent bout of exercise. The length of the adaptation differs among the measures such that when the exercise regimens are separated by 6 wk, all measures show a reduction in response on the second, compared with the first, bout. After 10 wk, only CK and muscle shortening show a reduction in response. After 6 months only the CK response is reduced. A combination of cellular factors and neurological factors may be involved in the adaptation process.

Frontal lobe functions in attention deficit disorder with and without hyperactivity: a review and research report.

Abstract: We review 22 neuropsychological studies of frontal lobe functions in children with attention deficit disorder with and without hyperactivity (ADD/+H,ADD/-H). Some measures presumed to assess frontal lobe dysfunctions were not reliably sensitive to the deficits occurring in either form of ADD. Tests of response inhibition more reliably distinguished ADD/+H from normal children. Where impairments were found on other tests between ADD and normal subjects, they were highly inconsistent across studies and seemed strongly related to age of the subjects and possibly to the version of the test employed. Other methodological differences across studies further contributed to the discrepant reports. The co-morbidity of other disorders, such as learning disabilities (LD) and conduct problems, with ADD may be an additional confounding factor in some, though not all, of these studies. In a separate study, children with ADD/+H (n=12) were then compared on frontal lobe tests to three other groups: ADD/-H (n=12), LD but no ADD (n=11),and normal children (n=12) statistically covarying for differences in conduct problems across groups. Most measures did not distinguish among these groups. Both ADD groups made more omission errors on a Continuous Performance Test (CPT) than the normal group. All three clinical groups performed more poorly on the word and interference portions of the Stroop Test. Thus, while both types of ADD share some apparent similarities in deficits on a few frontal lobe tests in this study, the totality of existing findings suggests an additional problem with perceptual-motor speed and processing in the ADD/-H group.

Middle management involvement in strategy and its association with strategic type: A research note

Abstract: This paper reports the results of a study that investigated the strategic involvement of 259 middle managers in 25 organizations. Drawing from previous clinical research, a theoretical typology of middle management roles in strategy is developed. Measures for each role are derived, and the relationship between middle management strategic involvement and Miles and Snow's (1978) strategic type is examined. Results suggest the usefulness of these measures in assessing both the level and type of middle management strategic activity. In addition, the findings show that middle managers in Prospectors report significantly higher levels of upward and divergent forms of strategic involvement than those in Analyzers and Defenders. Traditionally, middle-level managers have not been considered part of the strategy process except in providing informational inputs and directing implementation. Contemporary theory and descriptions suggest, however, that middle managers regularly attempt to influence strategy and often provide the impetus for new initiatives (Burgelman, 1983a,b; Mintzberg and Waters, 1985). Bower (1970) was one of the first to recognize the contributions of middle managers: they '... are the only men [sic] in the organization who are in a position to judge whether [strategic] issues are being considered in the proper context' (297-298). More recently, empirical research has confirmed middle management's upward influence on strategic decisions (Schilit, 1987)

The INQUERY Retrieval System

Abstract: As larger and more heterogeneous text databases become available, information retrieval research will depend on the development of powerful, efficient and flexible retrieval engines. In this paper, we describe a retrieval system (INQUERY) that is based on a probabilistic retrieval model and provides support for sophisticated indexing and complex query formulation. INQUERY has been used successfully with databases containing nearly 400,000 documents.

Concepts of Osteoblast Growth and Differentiation: Basis for Modulation of Bone Cell Development and Tissue Formation:

Abstract: The combined application of molecular, biochemical, histochemical, and ultrastructural approaches has defined a temporal sequence of gene expression associated with development of the bone cell phenotype in primary osteoblast cultures. The peak levels of expressed genes reflect a developmental sequence of bone cell differentiation characterized by three principal periods: proliferation, extracellular matrix maturation and mineralization, and two restriction points to which the cells can progress but cannot pass without further signals. The regulation of cell growth and bone-specific gene expression has been examined during this developmental sequence and is discussed within the context of several unique concepts. These are (1) that oncogene expression in proliferating osteoblasts contributes to the suppression of genes expressed postproliferatively, (2) that hormone modulation of a gene is dependent upon the maturational state of the osteoblast, and (3) that chromatin structure and the presence of nucleosomes contribute to three-dimensional organization of gene promoters that support synergistic and/or antagonistic activities of physiologic mediators of bone cell growth and differentiation.

Cloning and domain structure of the mammalian splicing factor U2AF

Abstract: A complementary DNA clone encoding the large subunit of the essential mammalian premessenger RNA splicing component U2 snRNP auxiliary factor (U2AF65) has been isolated and expressed in vitro It contains two functional domains: a sequence-specific RNA-binding region composed of three ribonucleo protein-consensus sequence domains, and an arginine/serine-rich motif necessary for splicing but not for binding to pre-mRNA

An optimal lower bound on the number of variables for graph identification

Abstract: In this paper we show that Ω(n) variables are needed for first-order logic with counting to identify graphs onn vertices. Thek-variable language with counting is equivalent to the (k−1)-dimensional Weisfeiler-Lehman method. We thus settle a long-standing open problem. Previously it was an open question whether or not 4 variables suffice. Our lower bound remains true over a set of graphs of color class size 4. This contrasts sharply with the fact that 3 variables suffice to identify all graphs of color class size 3, and 2 variables suffice to identify almost all graphs. Our lower bound is optimal up to multiplication by a constant becausen variables obviously suffice to identify graphs onn vertices.

Parenting Stress Among Families of Children with Attention Deficit Hyperactivity Disorder

Abstract: Prior research has shown that parenting stress levels can be quite high among families of children with attention deficit hyperactivity disorder (ADHD). This study investigated the degree to which such stress was related not only to the child's ADHD, but also to various other child, parent, and family-environment circumstances. Multimethod assessments were conducted on 104 clinic-referred children with ADHD. Data collected from these subjects were entered into hierarchical multiple-regression analyses, utilizing the Parenting Stress Index as the criterion. The results showed that child and parent characteristics accounted for a substantial portion of the variance in overall parenting stress. The child's oppositional-defiant behavior and maternal psychopathology were especially potent predictors. The severity of the child's ADHD, the child's health status, and maternal health status also emerged as significant predictors. These findings are discussed in terms of their impact upon the clinical management of children with ADHD.

Reinforcement learning is direct adaptive optimal control

Abstract: Neural network reinforcement learning methods are described and considered as a direct approach to adaptive optimal control of nonlinear systems. These methods have their roots in studies of animal learning and in early learning control work. An emerging deeper understanding of these methods is summarized that is obtained by viewing them as a synthesis of dynamic programming and stochastic approximation methods. The focus is on Q-learning systems, which maintain estimates of utilities for all state-action pairs and make use of these estimates to select actions. The use of hybrid direct/indirect methods is briefly discussed. >

Lexical ambiguity and information retrieval

Abstract: Lexical ambiguity is a pervasive problem in natural language processing. However, little quantitative information is available about the extent of the problem or about the impact that it has on information retrieval systems. We report on an analysis of lexical ambiguity in information retrieval test collections and on experiments to determine the utility of word meanings for separating relevant from nonrelevant documents. The experiments show that there is considerable ambiguity even in a specialized database. Word senses provide a significant separation between relevant and nonrelevant documents, but several factors contribute to determining whether disambiguation will make an improvement in performance. For example, resolving lexical ambiguity was found to have little impact on retrieval effectiveness for documents that have many words in common with the query. Other uses of word sense disambiguation in an information retrieval context are discussed.

Recreation Specialization: Re-conceptualization from a Social Worlds Perspective

Abstract: This paper initiated development of a theory of recreation specialization from a social worlds perspective and provided empirical testing for some of the stated propositions. Recreation specializat...

Link between iron and sulphur cycles suggested by detection of Fe(n) in remote marine aerosols

Abstract: IRON is essential to the growth of organisms, and iron derived from the atmosphere may be the limiting nutrient for primary productivity in some oceanic regions1–6. Aeolian mineral dust is the chief source of marine iron in many areas1–3,5,7, but there is little information on the chemical form of the iron in this dust. Here we report that Fe(n) contributed 56±32% of the total iron in marine aerosol samples collected over the central North Pacific and 49 + 15% at Barbados. We suggest that the key reaction that produces Fe(n), and hence increases the solubility of marine aerosol iron in sea water, is [Fe(in)(OH)(H2O)5]2+ + H2O^ [Fe(n)(H2O)6]2+ + OH- (refs 8–10). The presence of Fe(n) in remote marine aerosols suggests that the OH radical has been produced in these heterogeneous reactions. From consideration of both the marine biological production of dimethylsulphide and the subsequent oxidation of reduced forms of sulphur in the atmosphere, we propose that the iron and sulphur cycles in both the atmosphere and the ocean may be closely coupled.

Irrational reactions to negative outcomes : evidence for two conceptual systems

Abstract: According to cognitive-experiential self-theory (CEST), individuals have 2 systems for processing information, a rational system and an experiential system. Research conducted under norm theory (NT) has provided impressive evidence of an if only (IO) effect associated with postoutcome processing of aversive events that are highly consistent with formulations in CEST. Two studies involving vignettes adapted from NT were conducted that tested 4 hypotheses and corollaries derived from CEST. It was demonstrated, in support of hypotheses, that the IO effect can be obtained with ratings of one's own and of a protagonist's specific behaviors, as well as with ratings of a protagonist's diffuse emotions (the usual procedure); that a rational orientation decreases the IO effect; that increasing the intensity of outcomes increases it; and that priming the experiential system reduces people's ability to subsequently think rationally. The theoretical and research implications of these findings are discussed.

Phonological codes are used in integrating information across saccades in word identification and reading.

Abstract: A major issue in reading is the extent to which phonological information is used in visual word perception. The present experiments demonstrated that phonological information acquired on 1 fixation from a word in the parafovea is used to help identify that word when it is later fixated. A homophone of a target word, when presented as a preview in the parafovea, facilitated processing of the target word seen on the next fixation more than a preview of a word matched with the homophone in visual similarity to the target word. This facilitation was observed both in the time to name an isolated target word and in the fixation time on the target word while silently reading a sentence; the preview was virtually never consciously identified in either task. Because the visual similarity of the preview to the target also plays a part in the facilitative effect on the preview, however, codes other than phonological codes are preserved across saccades.

Toward a More Comprehensive Theory of Food Labels

Abstract: Food labels play important third-party roles in the food marketing system through their impact on product design, advertising, consumer confidence in food quality, and consumer education on diet and health. However, current analysis focuses overwhelmingly on the label's direct use as a point-of-purchase shopping aid, even though such use is limited by consumers' information processing abilities and time. In rewriting label regulations, policy makers should consider the benefits and costs of the broad array of roles labels serve, with evaluation of alternative regimes based on their impacts on consumer behavior and seller strategy.

Effects of disconfirmed consumer expectations on food acceptability

Abstract: Three studies were conducted to assess the effects of disconfirmed consumer expectations on food acceptability In the first, disconfirmed expectations for the sensory attributes of an edible film had a negative effect on acceptability of the film Greater disconfirmation resulted in lower acceptance and purchase intent In the second study, written product information was used to establish three levels of expected acceptability and expected bitterness for a novel fruit beverage Comparison of preexposure (expected) and postexposure (perceived) ratings of acceptability and bitterness supported an assimilation model of disconfirmation effects for conditions in which expectations of acceptability were high and expectations of bitterness were low A contrast effect was observed for bitterness judgments when expectations of bitterness were high Associative effects resulting from the expectation manipulation were observed on other sensory attributes In the third study, expectations were manipulated to influence both direction (positive versus negative) and degree of disconfirmation for the acceptance of cola beverages Results provided further support for an assimilation model of these effects

Transfer of Learning by Composing Solutions of Elemental Sequential Tasks

Abstract: Although building sophisticated learning agents that operate in complex environments will require learning to perform multiple tasks, most applications of reinforcement learning have focused on single tasks. In this paper I consider a class of sequential decision tasks (SDTs), called composite sequential decision tasks, formed by temporally concatenating a number of elemental sequential decision tasks. Elemental SDTs cannot be decomposed into simpler SDTs. I consider a learning agent that has to learn to solve a set of elemental and composite SDTs. I assume that the structure of the composite tasks is unknown to the learning agent. The straightforward application of reinforcement learning to multiple tasks requires learning the tasks separately, which can waste computational resources, both memory and time. I present a new learning algorithm and a modular architecture that learns the decomposition of composite SDTs, and achieves transfer of learning by sharing the solutions of elemental SDTs across multiple composite SDTs. The solution of a composite SDT is constructed by computationally inexpensive modifications of the solutions of its constituent elemental SDTs. I provide a proof of one aspect of the learning algorithm.

Managing strategic consensus: the foundation of effective implementation

Abstract: Executive Overview A frequent complaint of senior executives is that middle and operating managers fail to take the actions necessary to implement strategy. As one top manager told us. “It's been rather easy for us to decide where we wanted to go. The hard part is to get the organization to act on the new priorities.” Implementation problems of this type are often the result of poor middle management understanding and commitment to strategy. In our research we've found that relatively few middle managers articulate the same goals as their superiors. More troublesome, other researchers have found that middle managers who disagree with strategic initiatives frequently work against their implementation. This article examines an approach to implementation that focuses on the level of strategic understanding and commitment shared by managers within the organization. A framework identifying four categories of strategic consensus is introduced and used as the basis for analyzing differences in how managers perce...

Polaron-pair generation in poly(phenylene vinylenes).

Abstract: The effects of weak magnetic fields on the photoconductivity of poly(p-phenylene vinylene) (PPV) and two derivatives, poly(1,4-phenylene-1,2-dimethoxyphenyl vinylene) (DMOP-PPV) and poly(2-phenyl-1,4-phenylene vinylene) (PPPV), were observed within the temperature range 130\char21{}350 K. These effects are attributed to the formation of interchain pairs involving a negative polaron and a positive polaron. A polaron pair is formed as a result of interchain electron transfer from a molecular exciton. The lifetime of a pair is estimated to be within the range of ${10}^{\mathrm{\ensuremath{-}}8\char21{}}$${10}^{\mathrm{\ensuremath{-}}9}$ s. Thermal dissociation of a polaron pair produces free charge carriers, and recombination of the pair regenerates a singlet or triplet exciton on a single conjugated segment of a chain.

Incontinence and troublesome behaviors predict institutionalization in dementia

Abstract: Factors predicting the early institutionalization of demented patients were studied in 143 outpatients using univariate and multivariate life-table methods. Four types of factors were evaluated for prognostic value: severity of functional impairment, behavioral disorders, individual patient characteristics, and type of caregiver. After follow-up of 19 +/- 12 months, 51 patients had been institutionalized. Increased global severity of dementia, the presence of troublesome and disruptive behaviors, and incontinence increased the likelihood of institutionalization. The best predictors of institutionalization were paranoia, aggressive behavior, and incontinence. Neither individual patient characteristics (age, education, and gender) nor caregiver relationship to the patient (male spouse, female spouse, and male or female child) influenced institutionalization. Since troublesome behavioral disorders are potentially treatable aspects of dementia leading to institutionalization, their management should be a major focus of therapy in dementia.

Free Ca2+ Gradient in Growing Pollen Tubes of Lillium

Abstract: Fluorescence ratiometric imaging of Lilium pollen tubes loaded with the Ca 2+ indicator Fura-2 dextran has revealed a distinct elevation of free intracellular calcium ion concentration ([Ca 2+ ] i ) at the extreme tip of actively growing Lilium pollen tubes that declines to a uniform basal level of 170 nM throughout the length of the tube. The calcium gradient occurs within the first 10–20 μm proximal to the tip. Experimental inhibition of tip growth, usually achieved through the injection of the Ca 2+ buffer 5,5′-dibromo BAPTA, results in the loss of the [Ca 2+ ] i gradient. Occasionally these inhibited cells reinitiate growth, and when they do so ratio imaging reveals that the tip gradient of free [Ca 2+ ] i re-emerges. The results presented here are very different from those previously published by revealing the presence of the [Ca 2+ ] i gradient that is restricted to the 10–20 μm adjacent to the tube tip. Further, these experiments demonstrate a strict correlation between the presence of a [Ca 2+ ] i gradient, and tip growth in Lilium pollen tubes.