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PubMed1990

Dynamic interactions between accommodation and convergence.

Frequency-domain equations were derived for the current dual-interaction model of accommodation and convergence control, and its adaptive behavior was related to the system's parameters. Contrary to predictions based on the steady-state performance of the model [18], dynamic analysis showed that the AC/A is sensitive to the method of measurement and a procedure is established for its reliable determination. Additionally, the results provided theoretical support for the empirical finding that low AC/A and CA/C ratios are associated with high accommodative and convergence adaptation, respectively [15]. The derived equations should help future studies relate the physiological behavior of accommodative and convergence to specific model parameters.

Accommodation, Ocular↗
PubMed1996

Predictors of thought rebound.

Individual differences in the paradoxical thought rebound effect (increased thought expression following attempted thought suppression) were examined in two studies. In these two studies, the majority of Ss did not evidence thought rebound and, in both studies, it was found that a measure of thought rebound was correlated with other variables. In Study 1, a four-factor regression model predicted thought rebound (R2 = 0.1477). The significant predictors were: (1) ACT Composite (higher ACT predicted more rebound); (2) gender, (3) thought intrusion frequency during suppression; and (4) the interaction of gender and thought intrusion frequency (for male Ss only, more thought intrusions during suppression predicted more rebound). In Study 2, a replication regression model (R2 = 0.1408) cross-validated the ACT effect observed in Study 1. A Study 2 extension model (R2 = 0.2154) found the following significant predictors of thought rebound: (1) obsessionality (less obsessionality predicted more rebound); (2) trait anxiety (less anxiety predicted more rebound); (3) race (whites rebounded more than blacks); (4) gender; (5) 16 PF independence; and (6) the interaction of gender and 16 PF independence (for male Ss only, more independence predicted more rebound). The implications of these results for thought rebound theory are discussed.

Adult↗
PubMed2004

Influence of food dispersion on feeding activity and social interactions in captive Lophocebus albigena and Cercocebus torquatus torquatus.

We analysed the impact of the distribution of food items on feeding activity and social interactions in captive red-capped and grey-cheeked mangabeys. Three different feeding situations were presented: food items were either placed in a single heap or dispersed in several smaller heaps on the ground or in space. Social interactions were estimated by the frequency of positive, as well as of negative social interactions and by the structure of visual social attention. Feeding activity was estimated by proximity to food and feeding frequency. When food items were presented in single heaps, the adult males monopolized the food and monitoring of conspecifics increased. Social interactions and social gazes decreased in numbers when food items were dispersed in 3D. Gazes were directed more frequently towards the adult males when food items were presented in a single heap. Juveniles and some nonreproductive adult monkeys were the most affected by food competition situations. Inter-group variations, within a given species, of the behavioural responses observed in relation to the distribution of food items were evidenced. This suggests that social context, i.e., individual histories and relationship between group members, plays an important part in the expression of the activities of each member in a group.

Age Factors↗
PubMedDate not supplied

Obese women's perceptions of their physicians' weight management attitudes and practices.

BACKGROUND: Obesity has reached epidemic proportions in the United States. Primary care physicians will see increasing numbers of patients with long-term weight management problems. OBJECTIVE: To examine obese women's perceptions of their physicians' weight management attitudes and practices. DESIGN AND SETTING: Women who participated in obesity trials at a university clinic completed a questionnaire that assessed their views of weight control provided by their primary care physician. PARTICIPANTS: The patients were 259 women whose age was 44.0 +/- 10.0 years; weight, 96.7 +/- 13.2 kg; and body mass index (calculated as weight in kilograms divided by the square of height in meters), 35.2 +/- 4.5 (all data given as mean +/- SD). MAIN OUTCOME MEASURES: Using 7-point scales (1 indicates low; and 7, high), patients rated their satisfaction with care provided for their general health and that for their obesity. They also identified methods their physician recommended for weight management and the frequency of negative interactions with their physician concerning weight control. RESULTS: Participants were generally satisfied with the care they received for their general health and with their physicians' medical expertise (mean scores, 6. 1 and 6.2, respectively). They were significantly (P<.001) less satisfied with care for their obesity and with their physicians' expertise in this area (mean scores, 4.1 and 4.3, respectively). Almost 50% reported that their physician had not recommended any of 10 common weight loss methods, and 75% indicated they looked to their physician a "slight amount" or "not at all" for help with weight control. Only a small minority of patients (0.4%-8.0%) reported frequent, negative interactions with physicians concerning their weight. CONCLUSIONS: The last finding helps allay concerns that obese patients are routinely treated disrespectfully by physicians when discussing weight. The challenge, however, for primary care physicians appears to be providing patients better assistance with weight management.

Adult↗
PubMed2000

Similarities and differences in activities and agonistic behavior of male Eastern grey kangaroos (Macropus giganteus) in captivity and the wild.

The behavior of free-ranging and captive Eastern grey kangaroos Macropus giganteus, was observed by the same observers, with similar methods and under similar vegetational/climatic conditions in a 4.2-ha enclosure at Neuwied Zoo, Germany and at Grampians National Park, Victoria, Australia. Data were collected from a zoo group of 56 animals and a free-ranging mob of 50 to 60 animals. Males were individually identified and observed: 3 large males, 9 medium males, and 10 small males in the zoo, and 8 large, 9 medium, and approximately 10 small males in the National Park were present. Activities in both situations were very similarly distributed: Feed took up less time in the zoo, resting was almost similar in both situations, alert behavior was significantly different for small and medium males, locomotor activities were similar in large males and females, autogrooming occurred significantly more in the zoo only for females. Frequencies of social interactions were slightly greater for large males and females in the zoo. Agonistic behavior in males was more frequent in the zoo situation, except for ritualized fights. Sequences of agonistic behavior were more predictable in the zoo. No differences in escalation tendencies toward potentially injurious fighting could be found. Zoo Biol 19:529-539, 2000. Copyright 2000 Wiley-Liss, Inc.

Journal Article↗
PubMed1991

Behavioral development and maternal care in tufted capuchins (Cebus apella) and squirrel monkeys (Saimiri sciureus) from birth through seven months.

Fourteen infant capuchins and eight squirrel monkeys reared by their mothers in captive species-typical social groups were observed from birth through 7 months. Motoric altriciality of the neonatal capuchin relative to the squirrel monkey is a key feature of behavioral differences between the species in the first few months after birth. Infants of the two species differed substantially in age at onset of independent locomotion, the developmental profile of independent activities, and the overall amount and rate of particular social activities. Capuchins displayed a lag of 7 weeks relative to squirrel monkeys in the pattern of increasing time spent alone; lags in other indices of independent activity and exploratory behaviors were also evident, although not as clear-cut. The species also differed substantially in the nature and frequency of social interactions between infants and others. Capuchins, especially later-born infants of multiparous mothers, experienced a more socially interactive infancy than squirrel monkeys. Contrasts in behavioral developmental and infant care in the two species are related to the timing and duration of the weaning process.

Age Factors↗
PubMed2007

Utilization review of concomitant use of potentially interacting drugs in Thai patients using warfarin therapy.

PURPOSE: In Thailand, there has been no study determining the concomitant use of medications, known to potentially interact with warfarin, in patients receiving warfarin therapy. This paper examined the frequency of which specific interacting drugs were concomitantly used in warfarin users. METHODS: We retrospectively examined the database of warfarin outpatient medical records from a regional 756-bed hospital located in the north of Thailand. All patients receiving warfarin from 10 June 1999 to 4 August 2004 were reviewed to identify all drugs possessing interaction potential with warfarin. The potential of significant interactions were divided into high, moderate and low, according to the extent of evidence documented in textbooks and literature. RESULTS: Among 1093 patients receiving warfarin therapy, 914 (84%) patients received at least one potentially interacting drug and half of them (457 patients) received at least one drug with high potential for interaction. The most frequently concomitant drug that increased INR was acetaminophen (63%, 316/457). Propylthiouracil was the most frequently concomitant drug that decreased INR response (4%, 19/457), while diclofenac was the most frequently concomitant drug that increased bleeding risk (16%, 73/457). CONCLUSIONS: About a half of patients receiving warfarin therapy was prescribed concomitant drug(s) that has a high potential of interactions with warfarin. These patients should be closely monitored and counselled to watch for signs and symptoms of bleeding and thrombosis to avoid adverse events associated with drug interactions.

Acetaminophen↗
PubMed1999

Worker age, size and social status in queenless colonies of the ant Leptothorax gredleri.

Workers in queenless colonies of the ant Leptothorax gredleri form dominance hierarchies by antennation bouts and biting. The frequency of aggressive interactions peaked when the ants became active again after hibernation, a second time in summer, when new workers eclosed from overwintered brood, and a third time when we experimentally removed the queen. High-ranking individuals were more active and had greater ovarian development than their low-ranking nestmates. We investigated what proximately determines a worker's social status. Neither age, previously shown to affect hierarchy rank in several other social insects, nor levels of fluctuating asymmetry appeared to be important in worker rank orders in L. gredleri. High-ranking workers were on average larger than low-ranking individuals and body size and rank were correlated in four of five colonies investigated. However, individuals of similar age but different social status did not differ in size. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMedDate not supplied

Verb-noun double dissociation in aphasic lexical impairments: the role of word frequency and imageability.

Neurolinguistic studies have provided important evidence regarding the organization of lexical representations and the structure of underlying conceptual knowledge; in particular, it has been shown that the retrieval of verbs and nouns can be damaged selectively. Dissociated lexical damage is proof of an independent mental organization of lexical representations and/or of the underlying processes. The aim of the present study is to estimate the rate of dissociated impairments for nouns and verbs on a large sample of mild to moderate aphasic patients and to investigate the mechanisms underlying such phenomena. In addition, the authors wished to verify to what degree the impairment for nouns and verbs is related to a specific type of language disorder. A confrontation naming task for verbs and nouns was administered to 58 aphasic patients. The major lexical (word frequency and age of acquisition) and semantic variables (familiarity and imageability of the underlying concept) were considered for each noun and verb used in the task. Verbs were distinguished by major functional classes (transitive, intransitive, and ergative verbs). The data collected from this task were analyzed twice: (i) as a group study comparison of major aphasic subgroups and (ii) as a multiple single case study to evaluate the differences on the naming of verbs and nouns and the effect of the lexical semantic variables on each individual patient. The results confirm the existence of dissociated naming impairments of verbs and nouns. Selective impairment of verbs is more frequent (34%) than that of nouns (10%). In many cases, the dissociated pattern of naming impairment disappeared when the effect of the concomitant variables (word frequency and imageability) was removed, but in approximately one-fifth of the cases the noun or verb superiority was preserved. Noun superiority emerged in five of six agrammatic patients. Both the naming of verbs (n = 9) or of nouns (n = 6) could be impaired selectively in fluent aphasic patients. The results lend support to the hypothesis of an independent mental organization of nouns and verbs, but a substantial effect of imageability and word frequency suggests an interaction of the naming impairment with underlying lexical and semantic aspects.

Aphasia, Wernicke↗
PubMed1985

Entrainment of two coupled van der Pol oscillators by an external oscillation. As a base of "holonic control".

A system composed of two coupled internal oscillators and an external oscillation is studied as a model of biological control systems. The type of interaction between the internal oscillators is a mutual and dissipative one. Three macroscopic states of the internal oscillators are demonstrated in the absence of the external oscillation. Strict and loose entrainment regions of the internal oscillators by the external oscillation are shown in respect to the intensity of the mutual interaction, the intrinsic frequency difference of the internal oscillations, and the magnitude and frequency of the external oscillation. On the other hand, an idea of "holonic system" is introduced and the fundamental properties of the model as a holonic system are elucidated.

Animals↗
PubMed1988

The social behavior of depressed children: an observational study.

Few investigations have examined directly the psychosocial functioning of depressed children. In the present study, 20 depressed and 20 nondepressed fourth- and fifth-grade children were observed in free play during their recess period at school, and their self-perceptions were assessed in subsequent individual sessions. The 10 boys and 10 girls in each group were selected according to their scores on both the Child Depression Inventory and the Peer Nomination Inventory of Depression. Analyses conducted on the eight categories of behavioral observations revealed significant differences between the social behavior of the depressed and the nondepressed children. Although the depressed children made more overtures for social contact than did the nondepressed children and were approached by other children more frequently, they spent more time alone and engaged in a higher frequency of negative interactions with their peers. Consistent with these results, the depressed children's responses to the Self-Perception Profile for Children indicated that they experienced themselves as less socially competent in general, as well as less competent across several specific domains of functioning. These findings are discussed as they relate to developmental processes, theories of adult depression, and recent studies on socially isolated children, and directions for future research in this area are offered.

Child↗
PubMed2004

Communal nesting and kinship in degus (Octodon degus).

Communal nesting is a fundamental component of many animal societies. Because the fitness consequences of this behavior vary with the relatedness among nest mates, understanding the kin structure of communally nesting groups is critical to understanding why such groups form. Observations of captive degus (Octodon degus) indicate that multiple females nest together, even when supplied with several nest boxes. To determine whether free-living degus also engage in communal nesting, we used radiotelemetry to monitor spatial relationships among adult females in a population of O. degus in central Chile. These analyses revealed that females formed stable associations of > 2-4 individuals, all of whom shared the same nest site at night. During the daytime, spatial overlap and frequency of social interactions were greatest among co-nesting females, suggesting that nesting associations represent distinct social units. To assess kinship among co-nesting females, we examined genotypic variation in our study animals at six microsatellite loci. These analyses indicated that mean pairwise relatedness among members of a nesting association (r=0.25) was significantly greater than that among randomly selected females (r=-0.03). Thus, communally nesting groups of degus are composed of female kin, making it possible for indirect as well as direct fitness benefits to contribute to sociality in this species.

Animals↗
PubMed2004

Latency of adaptive vergence eye movements induced by vergence-vestibular interaction training in monkeys.

Clear vision of objects that move in depth toward or away from an observer requires vergence eye movements. The vergence system must interact with the vestibular system to maintain the object images on the foveae of both eyes during head movement. Previous studies have shown that training with sinusoidal vergence-vestibular interaction improves the frequency response of vergence eye movements during pitch rotation: vergence eye velocity gains increase and phase-lags decrease. To further understand the changes in eye movement responses in this adaptation, we examined latencies of vergence eye movements before and after vergence-vestibular training. Two head-stabilized Japanese monkeys were rewarded for tracking a target spot moving in depth that required vergence eye movements of 10 degrees/s. This target motion was synchronized with pitch rotation at 20 degrees/s. Both target and chair moved in a trapezoidal waveform interspersed with random inter-trial intervals. Before training, pitch rotation in complete darkness without a target did not induce vergence eye movements. Mean latencies of convergence and divergence eye movements induced by vergence target motion alone were 182 and 169 ms, respectively. After training, mean latencies of convergence and divergence eye movements to a target synchronized with pitch rotation shortened to 65 and 53 ms, and vergence eye velocity gains (relative to vergence target velocity) at the normal latencies were 0.68 and 1.53, respectively. Pitch rotation alone without a target induced vergence eye movements with similar latencies after training. These results indicate that vestibular information can be used effectively to initiate vergence eye movements following vergence-vestibular training.

Adaptation, Physiological↗
PubMed1977

Dominance in a human adolescent group.

Primatological concepts and methods are applied to a 5-week, naturalistic observational study of six 13-year-old boys in a summer camp. The purpose is to illustrate similarities between a human adolescent group and other primate groups in the establishment and stability of a dominance hierarchy, indices and frequencies of dominance interactions, and characteristics of dominance relations. A hierarchy was evident after 3 days of camp and remained operative throughout the 5 weeks, becoming more stable over time. The dominance rank-order was significantly related to athletic ability, leadership, and bed position but not to trail position, popularity, body surface area, and physical maturity. The possible social effects of the dominance hierarchy are also discussed.

Adolescent↗
PubMed1986

Machine-cycling errors with foot switches in repetitive tasks. A workstation design simulation experiment.

In this experiment a non-hazardous industrial machine simulator was used to evaluate errors made when using a foot switch to initiate dangerous, repetitive machine motions. Subjects were experienced employees who normally operated metalworking presses and similar hazardous machines on jobs matching the simulation. Four variables (force needed to push switch to closure, the switch's force feedback felt by the subject, subject working posture, and hand task involved in stamping a simulated workpiece) were evaluated for their main and interactive effects upon frequency of machine-cycling errors in a repetitive task. Equipment problems which required immediate correction were introduced at a rate of 4.9 events/h. Also, three covariables (the rate of repetitive use of the switch to make hits on simulated workpieces, subject age and subject experience at foot switch-controlled workstations) were examined for their contribution to cycling errors. Although hand task was a significant effect in error prediction models containing the four primary variables, it was found that a model containing the hit rate covariate (rate of repeated use of the foot switch) provided the best predictor of the frequency of inadvertent actuation errors. An error threshold was observed at about 17.5 hits/min with a high linear correlation between hit rate and machine-cycling errors at higher hit rates. Based on results of the experiment, this report presents design considerations for workstations which use foot controls to help minimise the chance of machine-cycling errors and injury.

Journal Article↗
PubMed1988

Ultrastructural localization of neuropeptide Y and galanin immunoreactivity in the paraventricular nucleus of the hypothalamus in the rat.

Preembedding immunoperoxidase staining methods were used to allow ultrastructural localization of neuropeptide Y (NPY) and galanin immunoreactivity (IR) in the paraventricular nucleus (PVH) of the rat hypothalamus. NPY-IR was localized exclusively in axons and axon terminals which could be grouped into three types: (1) symmetric axo-somatic contacts predominantly with parvocellular neurons, many of which displayed neurosecretory specializations, (2) predominantly asymmetric contacts onto larger dendritic processes, including some of magnocellular neurosecretory neurons, and (3) predominantly symmetric contacts with small dendritic and spine-like profiles. Galanin-IR terminals displayed a more limited distribution and formed both symmetric and asymmetric contacts with parvocellular neurons, and primarily asymmetric contacts with larger dendritic shafts. Numerous dendritic and somatic profiles, including those of some magnocellular neurosecretory neurons, were lightly stained for galanin IR. These results establish that NPY and galanin IR afferents form a variety of conventional synaptic contacts in the PVH. The two peptidergic terminal types differed with respect to the frequency of their interaction with various postsynaptic targets and/or their distribution upon them. Both peptidergic inputs arise at least in part from brainstem catecholaminergic neurons, and the relationship of the present results to the fine structure of catecholaminergic terminals is discussed.

Animals↗
PubMed1983

Low doses of beta-endorphin increase social contacts of rats tested in dyadic encounters.

Social isolation for 7 days increases the frequency of social interactions of rats, when they are tested with non-isolated partners in dyadic encounters. Subcutaneous administration of beta-endorphin enhances the social interactions of the isolated animals. Especially contact behavior, which includes crawl over, mounting and social grooming is stimulated by beta-endorphin, whereas social explorative behavior and approaching/following are less or not changed by peptide treatment. Already 10 ng/kg of the peptide increases the social interactions, especially social contacts of the rats. Treatment with naltrexone does not interfere with the social interactions of the isolated animals, but completely antagonizes the beta-endorphin-induced increase of social behavior, suggesting that this effect of beta-endorphin is mediated by opiate receptor systems. It is postulated that beta-endorphin modulates close and intimate social contacts probably by its reward-inducing properties.

Animals↗