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PubMedDate not supplied

A profile of sexually active male adolescent high school students in Lima, Peru.

To document knowledge and attitudes regarding sexuality and sexual practices of male adolescent high school students in Lima, Peru, a self-administered, anonymous survey was completed by 991 male adolescents aged 12-19 as part of a School-Based Sex Education Intervention model. Questions concerned sociodemographic information; family characteristics; personal activities; knowledge and attitudes regarding sexuality; sexual experience; and contraceptive use. Knowledge related to sexuality was limited. Males tended to mainly discuss sexuality with their male peers (49.8%). Attitudes towards sexual activity and condom use were largely positive, although some males expressed ambivalent feelings towards the latter. Of the sample, 43% had ever had sex; age at first sexual intercourse was 13 years. While 88% of the sample would use condoms, 74% also gave reasons for not using them. Sexual activity was related to age, ever having repeated a grade, living with only one parent or in a mixed family, activities such as going to parties, use of alcohol, tobacco, and drugs, and viewing pornographic videos or magazines. Many male adolescents were at risk of causing an unintended pregnancy or acquiring an STD.

Adolescent↗
PubMedDate not supplied

[The history of Biblioteca de Manguinhos and its rare collections].

This article narrates the creation of Fundação Oswaldo Cruz Biblioteca de Manguinhos Library) and its rare collections of books, magazines, journals, brochures, leaflets and theses, important publications on the history of biological sciences and health from the seventeenth to the twentieth century. It also describes the rich original ornaments and decoration of the library room and its furniture. It recovers the history of the library these past hundred years, which is closely associated to the history of Fundação Oswaldo Cruz.

Brazil↗
PubMed2005

The "total" museum, a tool for social change.

Science museums encourage not only scientific knowledge and methodology, but also people's opinion about scientific issues. This has been the main concern of Barcelona's Museo de Ciência de la Fundación "la Caixa" throughout its twenty years of existence. According to the author of the present article, the goals of "total museology" comply with the new trend some museums have been following. So that this new trend becomes more sound and widespread, it is necessary to create new concepts for museology. The first science museums were natural history and tools and machinery museums, which displayed artifacts in glass cases to visitors. Their mission was also that of preserving collections for the use of scientists. Science museums of today display real phenomena and provide visitors' interaction with them. Whatever the topic it focus, a science museums is "concentrated reality" either of objects or phenomena. This is probably the main distinctive feature of museology and of other forms of scientific communication. For teachers and lecturers, words are the basic element of communication, for books and magazines, the written language. There are no films without images, as there is no radio with sounds. In a museum, there are no restrictions as to the use of stimulation, models, graphic images or new technology, but just as accessories to reality, never as reality itself.

Education↗
PubMed2006

[The transparent body: medical imaging and popular culture in the twentieth century].

In today's societies, successful new medical imaging technologies have focused unprecedented attention on the inside of the human body. These techniques have jumped the walls of the biomedical field per se, penetrating the fields of culture and law. The article traces a genealogy of twentieth-century medical techniques used to visualize the human body and brain, from X-rays to the more sophisticated CTs, MRIs, and PET scans. It explores the changes that these ever more numerous visualization techniques have occasioned in our corporality and examines how these technologies have been received in the courtroom and in popular culture, especially in literature, movies, and magazines.

Culture↗
PubMed1987

Providing independent recreational activities to reduce stereotypic vocalizations in chronic schizophrenics.

We evaluated the effects of minimally supervised, independent recreational activities on stereotypic vocal behavior in two chronic schizophrenic patients. In baseline sessions, subjects were observed during unstructured free time in the psychiatric ward. In treatment sessions, therapists presented preferred recreational materials (magazines, models, and art projects), verbally prompted on-task behavior every 20 min, and, in one condition, administered contingent tokens. Independent recreational activities reduced medium-rate self-talk in one subject and high-rate mumbling in a second subject by 60%-70%. Results were the same with or without contingent tokens. Apparent self-maintaining characteristics of these vocal responses are discussed.

Adult↗
PubMed1989

Acquisition, generalization, and maintenance of question-answering skills in autistic children.

We conducted an investigation to evaluate the effects of a training strategy for teaching autistic students generalized responses to three forms of wh--questions (what, how, and why). Students were taught, using modeling and reinforcement procedures, to answer questions with magazine pictures as the referents. Each question form was divided into two or more subcomponents reflective of common social usage and was taught within the context of a modified multiple probe design across subcomponents. Following acquisition of each subcomponent, generalization to natural context and storybook questions was assessed; additional probes were conducted to assess responding over time and whether acquisition of responses to questions promoted question-asking skills. Results showed that the picture training procedure was effective in teaching a generalized response to questions for which the relevant cue was visible, whereas specific generalization programming was required for situations in which the relevant cue was not visible. All acquired responses were durable over time.

Autistic Disorder↗
PubMed1966

The motivational properties of schedule-induced polydipsia.

Schedule-induced polydipsia occurred during initial magazine training to Noyes pellets (45 mg), disappeared when lever-pressing was acquired on a continuous reinforcement schedule (CRF), and reappeared when the food contingency was changed to a 1-min variable interval schedule (VI 1 min). Polydipsia also developed under a VI 1 min food schedule when water was concurrently available on various fixed ratios (FR), rather than being freely available. The level of the polydipsia and its motivating properties allow it to be classified as a form of adjunctive behavior.

Animals↗
PubMed1968

A demonstration of auto-shaping with monkeys.

The Brown-Jenkins auto-shaping procedure for pigeons was found applicable to monkeys. Repeated pairings of lighted keys with reinforcement generated key-pressing behavior. The animals rapidly learned a simultaneous light-dark discrimination. The topographies of key-pressing and magazine behavior differed; the food tray was not illuminated.

Animals↗
PubMed1969

Variability of response location for pigeons responding under continuous reinforcement, intermittent reinforcement, and extinction.

The effect of several reinforcement schedules on the variability in topography of a pigeon's key-peck response was determined. The measure of topography was the location of a key peck within a 10-in. wide by 0.75-in. high response key. Food reinforcement was presented from a magazine located below the center of the response key. Variability in response locus decreased to a low value during training in which each response produced reinforcement. Variability increased when fixed intervals, variable intervals, random intervals, or extinction were scheduled.

Journal Article↗
PubMed1970

Conditioned reinforcement and discrimination performance.

Pigeons were trained in a three-key chamber to peck one side key in the presence of a vertical line on the center key and to peck the other side key in the presence of a horizontal line. Correct choice responses were reinforced with food according to fixed- and variable-ratio, fixed-interval, and differential-reinforcement-of-long-latency schedules of reinforcement. For each schedule, the birds performed under each of two conditions: (1) each correct choice response produced a brief presentation of stimuli intermittently paired with food, then the next trial; (2) each correct choice response produced an intertrial interval only. For all schedules except one long latency schedule, response rates were higher under the condition of brief stimulus presentation than under the comparable control condition. Presentation of brief magazine stimuli increased choice accuracy. The amount of change in accuracy was correlated with the rate of food presentation. Performance under the schedules with highest food reinforcement rates showed no enhancement; performance under the schedules with the lowest reinforcement rates showed the greatest enhancement.

Journal Article↗
PubMed1978

Behavioral contrast as differential time allocation.

In Experiment I, hooded rats were exposed to multiple variable-interval schedules of reinforcement in which manipulanda and reinforcement magazines at opposite ends of the experimental chamber were associated with the different components. Time allocated to each component was measured by recording the time spent by the subject in the appropriate half of the chamber. Positive behavioral contrast was observed for the comparison between multiple variable-interval 30-second variable-interval 30-second and multiple variable-interval 30-second variable-interval 90-second conditions for both response frequency and time allocation measures, but not for mean local response rate (response frequency per time allocated to a component). In Experiment II, rats were exposed to multiple variable-time schedules in which reinforcement was response independent. Time allocated to each component was measured for two conditions, multiple variable-time 30-second variable-time 30-second and multiple variable-time 30-second variable-time 90-second. Positive behavioral contrast of time allocation was exhibited. The results indicated that time allocation was differentially sensitive to changes in reinforcement probability, and that behavioral contrast may result from the differential allocation of time to the different components of the multiple schedule.

Journal Article↗
PubMed1979

A pellet feeder for the birds.

An alternative means of delivering food to pigeons in operant conditioning research is described. The feeder allows greater control of the amount of food delivered and reduces the amount of time necessary for the pigeon to collect the food. It is possible to extend the length of experimental sessions due to the reduction of food intake. Data obtained using the pellet feeder indicated that the control of responding is comparable to that observed with the standard grain-magazine feeder.

Journal Article↗
PubMed1980

On the discriminability of stimulus duration.

The performance of pigeons trained to detect differences in the duration of stimuli was analysed using a matching model of signal detection. Two white stimuli, S1 and S2, differing in duration, were arranged with equal probability on the center key of a three-key chamber. S1 was systematically varied from 5 seconds to 25 seconds while S2 remained constant at 30 seconds. On completion of the center-key stimulus, a peck on the center key turned on the two red side keys. A left-key response was "correct" when S1 had been in effect on the center key and a right-key response was "correct" on S2 trials. A correct response produced a 3-second magazine light accompanied intermittently by food. Incorrect responses produced 3-second blackouts. Detection performance was measured under two procedures. In the first, the obtained reinforcement ratio was uncontrolled by allowing the number of food reinforcements obtained for correct left- and right-key responses to vary as the stimuli were changed. In the second procedure, the presentation of food reinforcement was controlled by holding the obtained reinforcement ratio constant. Discriminability changed as a function of stimulus differences under both procedures. No such trend was found in response bias.

Animals↗
PubMed1981

Contrast and undermatching as a function of reinforcer duration and quality during multiple schedules.

Eight pigeons pecked keys under multiple variable-interval two-minute variable-interval two-minute schedules. In Experiment 1, the reinforcers were 2, 4, or 8 seconds access to a food magazine. In Experiments 2 and 3, the reinforcers were grains that had been determined to be most-, moderately-, or non-preferred. Both positive and negative behavioral contrast occurred when the reinforcers in one component were held constant and the duration or type of reinforcer obtained in the other component varied. Undermatching occurred when the relative rate of responding during a component was plotted as a function of the relative duration of the reinforcers in that component.

Journal Article↗
PubMed1986

Observational learning of two visual discriminations by pigeons: a within-subjects design.

Pigeon's observational learning of successive visual discrimination was studied using within-subject comparisons of data from three experimental conditions. Two pairs of discriminative stimuli were used; each bird was exposed to two of the three experimental conditions, with different pairs of stimuli used in a given bird's two conditions. In one condition, observers were exposed to visual discriminative stimuli only. In a second condition, subjects were exposed to a randomly alternating sequence of two stimuli where the one that would subsequently be used as S+ was paired with the operation of the grain magazine. In a third experimental condition, subjects were exposed to the performance of a conspecific in the operant discrimination procedure. After exposures to conspecific performances, there was facilitation of discriminative learning, relative to that which followed exposures to stimulus and reinforcement sequences or exposures to stimulus sequences alone. Exposure to stimulus and food-delivery sequences enhanced performance relative to exposure to stimulus sequences alone. The differential effects of these three types of exposure were not attributable to order effects or to task difficulty; rather, they clearly were due to the type of exposure.

Animals↗
PubMed1994

Response acquisition by Siamese fighting fish (Betta splendens) with delayed visual reinforcement.

Male Siamese fighting fish, Betta splendens, swam through a ring in an aquarium, breaking a photocell beam and initiating an unsignaled, resetting delay interval. Following delays of 0 s, 10 s, or 25 s, a 15-s mirror presentation released an aggressive display by the fish. Swimming through the ring increased in the absence of either a period of acclimatization to the reinforcer (analogous to magazine training when appetitive reinforcers are used) or explicit training of the response by the experimenters. Response rates were a decreasing function of delay duration. Other fish exposed to a schedule of response-independent mirror presentations failed to acquire and maintain the response. The results demonstrate the robustness and generality of the phenomenon of response acquisition with delayed reinforcement. They further qualify earlier observations about behavioral mechanisms involved in the phenomenon.

Journal Article↗
PubMed1996

A computer touch-screen apparatus for training visual discriminations in rats.

We describe an operant conditioning apparatus that uses computerized touch-screen technology and is designed for the versatile and highly controlled testing of rats in a potentially wide variety of behavioral paradigms. Although computer-controlled touch-screen systems have been developed for use with pigeons, monkeys, and humans, analogous technologies and methods have not yet been developed for rats. The development of a touch-screen system for rats could enhance the efficiency of behavioral research with rats, and may offer a unique tool for studying animal learning. In the first test of the utility of the apparatus, 3 Sprague-Dawley rats learned to activate the touch screen only after the touch-screen panel was made slightly movable. These animals then learned to discriminate visual stimuli presented on the computer monitor, but only after the food magazine and pellet dispenser were moved to the rear of the chamber opposite the stimulus display and response window. In a test of the utility of the modified apparatus, 6 Long-Evans rats learned to activate the touch screen and learned one of three different simple discriminations using computer-generated, visually presented stimuli. A basic method for training rats to activate the computer touch screen and for visual discrimination training is described. Results show that rats learned to activate the touch screen and discriminate visual stimuli presented on a computer monitor. Potential applications and advantages of the touch-screen-equipped rat operant conditioning chamber are discussed.

Animals↗
PubMed1994

Integrated control of ectoparasites.

Integrated control of ectoparasites of veterinary importance is being implemented on a limited basis at present. However, several forces are accelerating a global shift to integrated pest management (IPM). These accelerating forces include the following: reduction in new chemical compounds registered for use on livestock and poultry universal development of resistance to pesticides heightened environmental sensitivities to exclusive dependence on pesticide-based control need for strategies which increase profits for the producer while decreasing costs to the consumer. Integrated pest control requires many technologies for incorporation into specific pest management systems. Individual components include new chemicals, formulations and delivery systems, biological control, mechanical control, immunological control, genetic control, and regulatory control. Computer simulation models based on a quantitative ecological database are invaluable in devising and monitoring IPM approaches to controlling ectoparasites which affect livestock and poultry. IPM strategies have been developed for pests of veterinary importance, but eventually these must be incorporated into total livestock production systems. For implementation, a number of major impediments to IPM must be overcome. These problems can best be solved through a vigorous technology transfer programme. In addition to face-to-face meetings between producers and extension agents, the implementation of IPM can be further encouraged at producer group meetings, through education of animal health professionals, by the publication of articles in producer magazines, and by radio and television broadcasts to the agricultural sector. Research focusing on the development of cost-effective and environmentally-compatible IPM systems is necessary for future progress.

Animals↗