Showing papers by "University of Maryland, Baltimore County published in 1989"

Components of hostility as predictors of sudden death and myocardial infarction in the Multiple Risk Factor Intervention Trial.

Abstract: We tested the hypothesis that hostility is associated with increased relative risk (RR) for coronary death and nonfatal myocardial infarction among participants in the prospective Multiple Risk Factor Intervention Trial (MRFIT). Cases (N = 192) were compared with matched controls (N = 384) on a variety of behavioral characteristics associated with the Type A behavior pattern (TABP), including three different but interrelated components of hostility. Logistic regression analyses revealed that only two of the eight TABP attributes analyzed on the overall sample were significant. Only total Potential for Hostility, when dichotomized into "low" and "high" categories, and the antagonistic interpersonal component of hostility (Stylistic Hostility) had positive unadjusted associations with coronary heart disease (CHD) incidence (RR = 1.7, p = 0.003; and RR = 1.5, p = 0.016, respectively). The global TABP and related paralinguistic attributes were not significantly related to CHD incidence. After adjustment for the traditional risk factors of age, serum cholesterol, blood pressure, and cigarette smoking, only dichotomous Potential for Hostility showed a significant relative risk (RR = 1.5, p = 0.032). Ordinal logistic regression revealed a nonsignificant effect.(ABSTRACT TRUNCATED AT 250 WORDS)

The stress-buffering role of spiritual support: Cross-sectional and prospective investigations.

Abstract: The contribution of spiritual support (perceived support from God) to well-being, especially under conditions of high versus low life stress, has received little empirical study. In the present research, the relationship of spiritual support to well-being for several high and low life-stress samples was examined. With demographic variables controlled, regression analyses indicated that spiritual support: 1) was inversely related to depression and positively related to self-esteem for high life-stress (recently bereaved) parents; and 2) in a prospective (longitudinal) analysis with pre-college depression controlled, spiritual support was positively related to personal-emotional adjustment to college for high life-stress (three or more life events), first-semester college freshmen. Spiritual support was not significantly related to well-being for low life-stress subsamples. The implications of the findings for future research and intervention are discussed.

Metacognition, comprehension monitoring, and the adult reader

Abstract: This article provides an overview and synthesis of the current literature on metacognition and comprehension monitoring among adult readers. It is organized around three major research questions: (1) How do adults conceptualize their own comprehension-fostering and comprehension-monitoring activities? (2) How effectively do adults evaluate and regulate their ongoing efforts to understand? (3) How successfully do adults assess the final products of their comprehension efforts? Cutting across these broad issues are questions concerning metacognitive differences as a function of reading ability, academic success, domain expertise, developmental level, and task variables. The research reveals that adults' conceptions of how they comprehend and how they monitor their comprehension are quite variable. In general, those who have more expertise, who are better readers, and who are more successful students seem to have greater awareness and control of their own cognitive activities while reading. The research also reveals that adults evaluate and regulate their ongoing efforts to understand, although there is considerable room for improvement in these skills. Finally, the research shows that adults are remarkably unsuccessful at assessing how well they have comprehended a text and whether or not they are ready to take a test on the material. The article closes with a discussion of recent intervention efforts aimed at enhancing the metacognitive skills of adult readers.

A retina with at least ten spectral types of photoreceptors in a mantis shrimp

Abstract: STOMATOPOD crustaceans, commonly named mantis shrimps, have compound eyes of unique design. A central band composed of six parallel rows of ommatidia separates two peripheral ommatidial groups, and all three regions view the same area of visual space1–3. In the central bands of members of the stomatopod superfamily Gonodactyloidea, four of the ommatidial rows are built of tiers of photoreceptors; in two of these rows, the photoreceptors themselves contain coloured filters4. Such a design could in principle produce many spectral classes of photoreceptors using only a single visual pigment4,5. We measured the absorption spectra of the coloured filters and the visual pigments in frozen sections of retinae of a typical species, Pseudosquilla ciliata, using end-on microspectrophotometry. The retina contains not one, but as many as ten visual pigments, each in a distinct photoreceptor class, having maximum absorbances at wavelengths from 400 to 539 nm. Because of the unique anatomy of stomatopod eyes, ten or more spectral types of photoreceptors exist in this species.

An Experimental Analysis of Rule-Governed Behavior

Abstract: Contingency-shaped behavior is behavior directly controlled by the relations between responses and their consequences. But behavior may also come under the control of antecedent stimuli, stimuli in the presence of which responses produce their consequences. We find important examples of such stimuli in human verbal communities, which arrange contingencies that bring behavior under the control of antecedent verbal stimuli called commands, instructions, or rules.

Security of attachment and infant-sibling relationships: a laboratory study.

Abstract: The relation between infant-sibling affective involvement and the attachment security of each child to the mother was examined in the present laboratory investigation. In mothers' presence, securely attached infants were less likely to protest and aggress against mothers and older siblings when mothers played only with the older child. In mothers' absence, more secure older siblings were more likely to respond to infant distress with caregiving than were less secure older siblings. Although infant attachment behavior to older siblings was rare, it occurred only when the older sibling was more secure. Sibling dyads with a secure infant and a more secure older child appeared to be most likely to develop nonantagonistic relationships, whereas sibling dyads with an insecure infant and a less secure older child appeared least likely to do so. These findings were discussed in terms of the putative role of attachment security in shaping sibling bonds.

Variance-Penalized Markov Decision Processes

Abstract: We consider a Markov decision process with both the expected limiting average, and the discounted total return criteria, appropriately modified to include a penalty for the variability in the stream of rewards. In both cases we formulate appropriate nonlinear programs in the space of state-action frequencies averaged, or discounted whose optimal solutions are shown to be related to the optimal policies in the corresponding “variance-penalized MDP.” The analysis of one of the discounted cases is facilitated by the introduction of a “Cartesian product of two independent MDPs.”

Putidaredoxin competitively inhibits cytochrome b5-cytochrome P-450cam association: a proposed molecular model for a cytochrome P-450cam electron-transfer complex.

Abstract: Cytochrome b5 has been genetically engineered to afford a fluorescent derivative capable of monitoring its association with cytochrome P-450cam from Pseudomonas putida [Stayton, P. S., Fisher, M. T., & Sligar, S. G. (1988) J. Biol. Chem. 263, 13544-13548]. In the mutant cytochrome b5, threonine is replaced by a cysteine at position 65 (T65C) and has been labeled with the environmentally sensitive fluorophore acrylodan. In this paper, the physiological P-450cam reductant putidaredoxin, an Fe2S2.Cys4 iron-sulfur protein, is shown to competitively inhibit the cytochrome b5 association, suggesting that cytochrome b5 and putidaredoxin bind to a similar site on the cytochrome P-450cam surface. Since the crystal structures for both cytochrome b5 and cytochrome P-450cam have been solved to high resolution, the complex has been computer modeled, and a good fit was found on the proximal surface of nearest approach to the P-450cam heme prosthetic group. The proposed model includes electrostatic contacts between conserved cytochrome b5 carboxylates Glu-44, Glu-48, Asp-60, and the exposed heme propionate with cytochrome P-450cam basic residues Lys-344, Arg-72, Arg-112, and Arg-364, respectively. Putidaredoxin has similarly been shown to contain a carboxylate-based binding surface, and the current results suggest that if the model is correct, then it also interacts at the proposed site, probably utilizing similar P-450cam electrostatic contacts.

A Two-Person Inspection Method to Improve Prog ramming Productivity

Abstract: A6xfmct-Thls paper reviews current research and investigates the effect of n two-person Inspeetion method on programmer productivity. This method is similar to tbe current larger team method in stressing f d t detection, but doCS not use a moderator. The experiment used a Pretest-Posttest Control Group design. An experimental and control group of novices each completed two programming assignments. The amount of time taken to complete each program. (Timel, Timel) was recorded for each subject. The subjects or the experlmental group did either a design inspection, a code inspection, o r both during the development of the second program. An analysis of variance was performed nnd the relationship between Timel and Time2 was modeled for both groups. A comparison of the models revealed (he experimental group improved significantly in programming speed as a result of using tbe two-person inspection. I t also a p peared as though this method was more elkctive at improving the performance of the slower programmers. This two-person method could have its application in those envimnmeats wbcre access to larger team resourcm Is nol available. If further researeta establishes consistency with this method then it might be useful IS a transition to the larger team method.

Community Settings as Buffers of Life Stress? Highly Supportive Churches, Mutual Help Groups, and Senior Centers

Abstract: Examined the stress-buffering potential of community settings in three studies. The first study focused on economic stress among 162 members of three churches, the second on bereavement stress among 80 members of eight mutual help groups for bereaved parents, and the third on bereavement stress among 85 members of six senior centers. In each study, high and low support settings were defined by aggregate measures. For churches and mutual help groups, high life stress individuals reported greater well-being in high support than low support settings while low life stress individuals did not differ across settings. Tangible aid receipt (churches) and friendship development (mutual help groups) contributed to the stress-buffering findings. For senior centers, aggregate setting support was related to well-being in main effect fashion. The implications for inquiry and action at the community setting level of analysis are discussed.

Factors Affecting the Acceptability of Suicide.

Abstract: The present study examined whether attitudes toward suicide vary as a function of the age and gender of the suicide victim, the gender of the evaluator, and the type of illness that precipitates the suicide The participants in the study were 780 college students who were administered a questionnaire consisting of one of twelve scenarios describing a fictitious individual who has decided to commit suicide, as well as a series of evaluative scales and questions about the individual and his/her decision The scenarios varied in terms of the age of the victim (ie, forty-five vs seventy), the gender of the victim, and the precipitating illness (ie, chronic depression, chronic physical pain, or terminal bone cancer) Evaluations of suicide tended to be significantly more favorable when the evaluators were male, when male victims were being judged, when elderly victims were being evaluated, or when terminal cancer was the precipitating illness

Multiple spectral classes of photoreceptors in the retinas of gonodactyloid stomatopod crustaceans

Abstract: 1. We examined the compound eyes of 2 species of gonodactyloid stomatopods, Gonodactylus oerstedii and Pseudosquilla ciliata, using end-on microspectrophotometry of frozen sections of dark-adapted retinas. 2. The cornea and crystalline cones of both species were virtually transparent from 350 to 700 nm. Primary screening pigment granules in the retinular cells had the broad absorption spectra typical of ommochromes. Colored vesicles, of unknown function, also were found in the cytoplasm of the retinular cells. The intrarhabdomal filters appeared to act as long-pass spectral filters, and had maximum optical densities in situ of 0.94 to 11.1. 3. A variety of visual pigments were found in both species, each in a specific retinal region. Their maximum absorption peaked at wavelengths from 400 nm to well beyond 530 nm. 4. Spectral sensitivity functions of all retinal regions were estimated. In both species, each of the 4 most dorsal ommatidial rows of the central band had a pair of narrow spectral sensitivitity curves, usually separated by 50 to 75 nm. These 4 pairs covered the spectrum from below 400 to beyond 650 nm. The other 2 rows of the central band had identical, broad sensitivity functions. Spectral sensitivities of all peripheral ommatidia in each species were identical, but different from any region of the central band. 5. These stomatopod species have retained the typical crustacean layered rhabdoms in the peripheral retina and the 2 most ventral rows of the central band, but have converted the photoreceptors of the 4 dorsal rows of the central band into as many as 8 narrowly tuned spectral classes. This design could serve a high-quality hue discrimination system.

Faces as releasers of contagious yawning: An approach to face detection using normal human subjects

Abstract: The yawn-evoking potency of variations in a 5-min series of 30 videotaped repetitions of a yawning face were compared with each other and with a series of 30 videotaped smiles to determine the ethological releasing stimulus for the fixed-action pattern of yawning and to understand the more general process of face detection. Animate video images of yawning faces in several axial orientations evoked yawns in more subjects than did featureless or smiling faces, and no single feature, such as a gaping mouth, was necessary to evoke yawns. The yawn recognition mechanism is neither axially specific nor triggered by an isolated facial feature.

Membranous intermediates in endocytosis are labile, as shown in a temperature-sensitive mutant.

Abstract: Membranous tubules, especially prevalent in mammalian absorptive epithelia and insect oocytes, are one of the pleomorphic endocytic compartments that have a role in receptor-mediated endocytosis. To determine whether these tubules are evanescent, and to investigate their temporal relationships with other endocytic intermediates, we studied these tubules during oocyte vitellogenesis in the temperature-sensitive mutant Drosophila melanogaster, shibiretsl. Raising the temperature of shibire oocytes for 1 min from 19 degrees C to 29 degrees C caused a loss of these membranous tubules. The percentage of membrane in tubules decreased from 36% at 19 degrees C to 1.5% after 5 min at 29 degrees C. Concomitantly, the amount of surface membrane increased from 64% at 19 degrees C to 98% after 5 min at 29 degrees C, causing surface membrane invaginations to extend deeper into the cortex. At 29 degrees C the cytoplasmic face of the plasma membrane was studded with coated pits, and the extracellular face was coated with electron-dense material. Return from 29 degrees C to either 19 degrees C or 26 degrees C for 1-2 min produced a rapid reappearance of tubules containing extracellular horseradish peroxidase in the cortex. These data suggest that tubular intermediates are evanescent structures, and that temperature shock (i) rapidly blocks their formation from the plasma membrane, (ii) causes existing tubules to rapidly recycle to the plasma membrane, and (iii) is rapidly reversed, as newly formed tubules derive their membrane and content from the cell surface.

Growth-rate-dependent regulation of 6-phosphogluconate dehydrogenase level mediated by an anti-Shine-Dalgarno sequence located within the Escherichia coli gnd structural gene.

Abstract: Previous work has shown that in Escherichia coli K-12 growth-rate-dependent regulation of expression of 6-phosphogluconate dehydrogenase, encoded by the gnd gene, occurs at the posttranscriptional level and is mediated by a negative control element that lies deep in the coding sequence, somewhere between codons 48 and 118. Deletion analysis of a growth-rate-regulated gnd-lacZ translational fusion showed that the element is the segment of gnd mRNA between codons 67 and 78 that is complementary to an extensive portion of the gnd ribosome-binding site, including its Shine-Dalgarno sequence. The boundaries of the element were further defined by the cloning of a synthetic "internal complementary sequence." The core internal complementary sequence element effected growth-rate-dependent regulation when placed at several sites between codon 40 and codon 69, but it severely reduced gene expression when moved to codon 13. The effect on regulation of single and double mutations introduced into the element by site-directed mutagenesis correlated with the ability of the respective mRNAs to fold into secondary structures that sequester the ribosome-binding site. Thus the gnd gene's internal regulatory element appears to function as a cis-acting antisense RNA.

Novel regulation of heat shock genes during carrot somatic embryo development.

Abstract: We have determined that somatic embryos of carrot exhibit a number of interesting and unusual properties when exposed to heat shock at different times in their development. Specifically, we have seen that mid-globular embryos can be arrested irreversibly in their development when heat-shocked, whereas all other stages of embryogenesis, both before and after this stage, are fully capable of normal development after the stress. In investigating the molecular basis of this developmental sensitivity to heat shock, using a cloned heat shock gene encoding a small heat shock protein, we have determined that globular embryos both synthesize and accumulate significantly less heat shock mRNA when compared with embryos of any other stage or to callus suspension cells. In fact, there appears to be no transcriptional induction of heat shock gene expression in response to heat shock during this time period; the gene is expressed at the same relatively low level both before and after heat shock. However, in spite of the low level of heat shock mRNA available, globular embryos synthesize the full complement of heat shock proteins in response to heat treatment. The globular embryos appear to accomplish this by translating the existing heat shock mRNAs at an elevated rate, which compensates for the low level of available mRNA. Once the embryos have progressed beyond the globular stage of development, regulation at the transcriptional level resumes, and the embryos again exhibit normal development after heat shock.

Relative Effectiveness of Two Behavioral Parent Training Programs

Abstract: Provided one of two behavioral parent training courses to 22 middle socioeconomic status (SES) and 18 lower SES mothers of 3- to 8-year-olds presenting problems in behavior management. Approximately half the mothers were taught using modeling and role playing, whereas the others were taught through readings, brief review tests, and discussions. Middle-SES mothers reported significantly greater child behavior change from pretraining to posttraining than did lower SES mothers. During structured observation, lower SES mothers in the modeling and role-playing condition used the skills they had been taught significantly more often than did lower SES mothers in the reading and discussion condition.

A smoothing technique for nondifferentiable optimization problems

Abstract: We introduce a smoothing technique for nondifferentiable optimization problems. The approach is to replace the original problem by an approximate one which is controlled by a smoothing parameter. The recession function is instrumental in the construction of the approximate problem. An a priori bound on the difference between the optimal values of the original problem and the approximate one is explicitly derived in term of the smoothing parameter. The relationships between the primal approximated problem and its corresponding dual are investigated.

Student Teaching as a Rite of Passage

Abstract: The purpose of this article is to use the concept of rites of passage to describe how cultural knowledge about teaching is acquired by neophytes during student teaching. Like other rites of passage as studied by van Gennep, Malinowski, Turner, and Moore and Myerhoff, this story of the induction of elementary student teachers follows the classic model: first the student teachers cut the ties that bind them to the ordinary world (rites of separation). Then they are secluded in the bush where a specialized body of knowledge unique to the professional community is transmitted to them (rites of transition). If they successfully survive all their trials, the novices are then ritually reinstated in the ordinary world with accompanying changes in their status, rights, and prerogatives (rites of incorporation). CULTURAL TRANSMISSION/ACQUISITION, RITES OF PASSAGE, STUDENT TEACHING, TEACHER INDUCTION

Contagious yawning and infant imitation

Abstract: Several authors have suggested that the neonate’s presumed ability to imitate the facial expressions or gestures of adult models may be the result of ethological fixed action patterns released by sign stimuli. Contagious yawning of adults is a precedent for such a facial fixed action pattern (i.e., a yawn) triggered by a facial stimulus (i.e., an observed yawn). Contagious yawning is an easily studied pseudoimitative act which can provide insights into both the problem of infant imitation and the more general issues concerning the detection and processing of information about faces. Contagious yawning also provides a reliable classroom demonstration of released behavior that always generates student interest and participation.

Transfer of function across members of an equivalence class

Abstract: A child's presses on response windows behind which stimuli were presented via computer monitor occasionally lit lamps arranged in a column; a present was delivered when all lamps in the column were lit. During the operation of a multiple schedule, the child first learned low rates of pressing in the presence of STAR and high rates in the presence of TREE. Later, in an arbitrary matching task, the child learned to select STAR given wiggly WORM and TREE given BLOCK. When WORM and BLOCK were inserted into the multiple schedule, the low and high rates respectively correlated with STAR and TREE transferred to them. Tests of reflexivity (identity matching) and of symmetry of the arbitrary matching implied that STAR and WORM had become members of one equivalence class, and TREE and BLOCK had become members of another.

Economic Well-Being Following Marital Termination A Comparison of Widowed and Divorced Women

Abstract: Separate studies of divorced and widowed women show increased odds of becoming poor following the termination of marriage. Both cross-sectional and longitudinal data suggest that the end of marriage is correlated with higher poverty rates. Less is known, however, about factors that influence economic well-being over time, and whether these factors are similar for widows and divorced women. This analysis uses data from the National Longitudinal Surveys cohort of mature women (1967-1982) to examine the probability of becoming poor after widowhood or divorce among mid-life women, and factors that seem to influence economic well-being. Findings show that 40% of widows and over one-quarter of divorced women fall into poverty for at least some time during the first five years after leaving marriage. The type of marital transition experienced by the woman is not a significant factor in economic well-being, but both age and prior economic standing have positive estimated effects.

Definition and Assessment of Coronary-Prone Behavior

Abstract: Any consideration of assessment issues regarding coronary-prone behavior must begin with a review and evaluation of the evidence that certain psychological/behavioral constructs are “coronary-prone,” i. e., that certain psychological/behavioral characteristics are associated with and/or predictive of such manifestations of coronary heart disease (CHD) as myocardial infarction, cardiac death, angina, and coronary atherosclerosis (coronary artery disease, CAD). On the basis of such evidence it will be possible to draw conclusions regarding the best available means of assessing coronary-prone characteristics, as well as what further research is needed to improve our ability to assess such characteristics.

NADH levels and solventogenesis in Clostridium acetobutylicum: New insights through culture fluorescence

Abstract: The metabolic relationship between the solventogenic state in Clostridium acetobutylicum and intracellular NADH levels was investigated using culture fluorescence as a technique for continuous monitoring of in vivo NADH levels. Continuous culture experiments showed that a transition from acidogenic to solventogenic state was accompanied by a decrease in culture fluorescence, which was interpreted as a decrease in NADH level. It appears that NADH/NAD+ turnover rates may be more significant than NADH levels in determining the metabolic state of the cell. This result provides important new information on regulation of the intracellular reduction state in Clostridium acetobutylicum. Culture fluorescence is shown to be a useful technique for non-invasive on-line monitoring of the metabolic state in continuous acetone-butanol fermentations.

Factors affecting the birth and death of mutual-help groups: the role of national affiliation, professional involvement, and member focal problem.

Abstract: Examined the predictive relationship of three variables to the birth and death of mutual-help groups for a statewide New Jersey sample of 3,152 groups over a 2-year period. The three variables studied were group affiliation with a national mutual-help organization, local professional involvement in group activities, and group members' type of focal problem. Log-linear logit analysis revealed that the best-fitting model included Affiliation Status x Professional Involvement, and Affiliation Status x Focal Problem interactions. Among unaffiliated groups, professional involvement was related to lower group mortality, while among affiliated groups it was related to higher group mortality. Unaffiliated behavior control groups had higher odds for mortality and for birth than either unaffiliated life stress groups or unaffiliated medical groups. Among main effect findings, unaffiliated groups had consistently higher odds for birth than affiliated groups. The implications for research and action are discussed.