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PubMed1989

The composition of imaginal transformations.

Three experiments examine the performance of composite imaginal spatial transformations using tasks in which people perform pairs of distinct imaginal transformations either in close succession or simultaneously. The principal aim of the investigation is to determine, for both modes of composition, whether imaginal transformations combine interactively or noninteractively to determine the temporal course of imaging performance. Specifically, does the time to imagine a given composite transformation reflect the independent contributions of its component transformations, or do component transformations have different effects within different composites? Results obtained under a number of distinct task conditions are most consistent with the proposal of noninteractive composition. However, the temporal effects of particular imaginal transformations are neither consistent nor readily predictable across different task conditions. Implications of these results for analogue-spatial models, task demand, and procedural accounts of imaging are discussed.

Adolescent↗

PubMed2000

The effect of divided attention on memory for items and their context.

Memory for context, in comparison to memory for items, is a more demanding task and requires more attentional resources. We examined differences between item and context memory using divided attention at encoding and retrieval. Participants were presented with word lists and were instructed to learn the items (i.e., words), the intrinsic context (i.e., the colour of the cards on which each word was presented), and the extrinsic context (i.e., the temporal order of the words). Among 72 young adults, in comparison to conditions of full attention, divided attention applied at encoding only or retrieval only resulted in equally lower performance on all memory tasks; in contrast, divided attention applied at both encoding and retrieval resulted in lower performance only on memory for temporal order. The findings support the idea that memory for temporal order requires greater attentional resources and strategic processing than memory for items.

Adolescent↗

PubMed1981

Voice pitch as an aid to lipreading.

The totally deafened adult, unable to make use of a hearing aid, has no alternative to lipreading for everyday communication. Lipreading, however, is no substitute for hearing speech. Many lipreaders have great difficulty in ideal conditions and even the best lipreaders find the task demanding and tiring. Prosthetic attempts to substitute for lost hearing have centred on three distinct types of intervention, visual, tactile, and electrocochlear. As none of these is likely to yield a good understanding of a speech independent of lipreading in the near future, we have attempted to isolate relatively simple patterns of stimulation that, although not intelligible in themselves, well aid lipreading. From this point of view, the fundamental frequency or 'pitch' of the voice is the most important pattern element because if provides both segmental and suprasegmental information and is practically invisible. It thus complements the visual information already available on the face. As we show here, with the voice pitch presented acoustically, normal listeners can lipread a speaker reading continuous text at up to two and a half times the rate possible on the basis of lipreading alone. The pitch signal by itself, of course, is completely unintelligible. Although our work is primarily concerned with methods of electrical stimulation of the cochlea, it has implications for other sensory substitution techniques, the design of special purpose hearing aids and current theories of speech perception.

Female↗

PubMed1998

Dynamic cortical activity in the human brain reveals motor equivalence.

That animals and humans can accomplish the same goal using different effectors and different goals using the same effectors attests to the remarkable flexibility of the central nervous system. This phenomenon has been termed 'motor equivalence', an example being the writing of a name with a pencil held between the toes or teeth. The idea of motor equivalence has reappeared because single-cell studies in monkeys have shown that parameters of voluntary movement (such as direction) may be specified in the brain, relegating muscle activation to spinal interneuronal systems. Using a novel experimental paradigms and a full-head SQUID (for superconducting quantum interference device) array to record magnetic fields corresponding to ongoing brain activity, we demonstrate: (1), a robust relationship between time-dependent activity in sensorimotor cortex and movement velocity, independent of explicit task requirements; and (2) neural activations that are specific to task demands alone. It appears, therefore, that signatures of motor equivalence in humans may be found in dynamic patterns of cortical activity.

Brain↗

PubMed2005

Toward genome-wide SNP genotyping.

Genome-wide association studies with SNP markers are expected to allow identification of genes that underlie complex disorders. Hundreds of thousands of SNP markers will be required for comprehensive genome-wide association studies. The development of microarray-based methods for SNP genotyping on this scale remains a demanding task, despite many recent advances in technology for the production of high-density microarrays. A key technical obstacle is the PCR amplification step, which is required to reduce the complexity of and gain sufficient sensitivity for genotyping SNPs in large, diploid genomes. The multiplexing level that can be achieved in PCR does not match that of current microarray-based methods, making PCR the limiting step in the assays. Highly multiplexed microarray systems for SNP genotyping have recently been developed by combining well-known reaction principles for DNA amplification and SNP genotyping in clever ways. These new methods offer the potential of genome-wide SNP mapping of genes involved in complex diseases in the foreseeable future, provided that issues related to selection of the optimal SNP markers, sample throughput and the cost of the assays can be addressed.

DNA-Directed DNA Polymerase↗

PubMed2005

X-ray-diffraction characterization of Pt(111) surface nanopatterning induced by C60 adsorption.

Understanding the adsorption mechanisms of large molecules on metal surfaces is a demanding task. Theoretical predictions are difficult because of the large number of atoms that have to be considered in the calculations, and experiments aiming to solve the molecule-substrate interaction geometry are almost impossible with standard laboratory techniques. Here, we show that the adsorption of complex organic molecules can induce perfectly ordered nanostructuring of metal surfaces. We use surface X-ray diffraction to investigate in detail the bonding geometry of C(60) with the Pt(111) surface, and to elucidate the interaction mechanism leading to the restructuring of the Pt(111) surface. The chemical interaction between one monolayer of C(60) molecules and the clean Pt(111) surface results in the formation of an ordered sqrt[13] x sqrt[13]R13.9 degrees reconstruction based on the creation of a surface vacancy lattice. The C(60) molecules are located on top of the vacancies, and 12 covalent bonds are formed between the carbon atoms and the 6 platinum surface atoms around the vacancies. In-plane displacements induced on the platinum substrate are of the order of a few picometres in the top layer, and are undetectable in the deeper layers.

Adsorption↗

PubMed2000

Functional neuroimaging of cognition impaired by a classical antihistamine, d-chlorpheniramine.

Antihistamine induced cognitive decline was evaluated using positron emission tomography (PET) measurement of histamine H1 receptor (H1R) occupancy and regional cerebral blood flow (rCBF). Cognitive performance in attention-demanding task deteriorated dose-dependently and the effects were statistically significant after the treatment of 2 mg of d-chlorpheniramine. There was no significant change in subjective sleepiness in the same dose. The regional blockade of H1R was observed mainly in the frontal, temporal and anterior cingulate cortices, and the intravenous administration of d-chlorpheniramine as a therapeutic dose (2 mg) blocked over 60% of H1R in the frontal cortices. The results from activation study using visual discrimination tasks demonstrated that enhanced activity in the right prefrontal and anterior cingulate cortices as well as a decreased activity in the left temporal and frontal cortices and midbrain after the treatment of d-chlorpheniramine. There were no changes in global CBF for the subjects treated with 2 mg d-chlorpheniramine (pre; 44.8+/-3.3 ml dl(-1) min(-1) vs post; 44.4+/-4.7 ml dl(-1) min(-1)). The results indicated that the attention system of human brain could be altered by therapeutic doses of H1R antagonists. These findings provide the information as to the potential risk of antihistamines in our daily activities. British Journal of Pharmacology (2000) 129, 115 - 123

Adult↗

PubMed2004

Regulation of working memory by dopamine D4 receptor in rats.

Working memory is regulated by neurotransmitters in prefrontal cortex (PFC), including dopamine and norepinephrine. Previous studies of dopamine function in working memory have focused on the D1 and D2 receptors, with most evidence suggesting a dominant role for the D1 receptor. Since the dopamine D4 receptor is highly expressed in PFC, we hypothesize that it may also contribute to working memory. To test this hypothesis, we examined behavioral effects of L-745,870, a highly selective, centrally active, D4 antagonist, using a delayed alternation task in rats. Task performance was dose-dependently affected by the D4 antagonist, depending on individual baseline functional status of working memory. In rats with good baseline performance, the D4 antagonist had no effects at low doses, whereas high doses disrupted working memory. In rats with poor baseline working memory, the D4 antagonist significantly improved working memory at low doses, and higher doses were not distinguishable from vehicle controls. Effects of the D4 antagonist among poor performers were most robust when task demand for working memory was high, with lesser effects at lower demand level, suggesting that such effects were selective for working memory. The present findings indicate a significant role of the D4 receptor in working memory, and suggest innovative, D4-based, treatment of cognitive deficits associated with neuropsychiatric disorders.

Animals↗

PubMed2006

Proteome-on-a-chip: mirage, or on the horizon?

Proteomics has emerged as the next great scientific challenge in the post-genome era. But even the most basic form of proteomics, proteome profiling, i.e., identifying all of the proteins expressed in a given sample, has proven to be a demanding task. The proteome presents unique analytical challenges, including significant molecular diversity, an extremely wide concentration range, and a tendency to adsorb to solid surfaces. Microfluidics has been touted as being a useful tool for developing new methods to solve complex analytical challenges, and, as such, seems a natural fit for application to proteome profiling. In this review, we summarize the recent progress in the field of microfluidics in four key areas related to this application: chemical processing, sample preconcentration and cleanup, chemical separations, and interfaces with mass spectrometry. We identify the bright spots and challenges for the marriage of microfluidics and proteomics, and speculate on the outlook for progress.

Animals↗

PubMed2005

Persuasive writing in children, adolescents, and adults: a study of syntactic, semantic, and pragmatic development.

PURPOSE: Persuasive writing is a demanding task that requires the use of complex language to analyze, discuss, and resolve controversies in a way that is clear, convincing, and considerate of diverse points of view. This investigation examined selected aspects of later language development in the context of persuasive writing. The purpose of the study was to obtain current information that could be used to design collaborative instruction involving speech-language pathologists and classroom teachers. In schools today, these professionals often work closely together to facilitate students' language development, including their ability to write persuasively. METHOD: Persuasive writing was investigated in typically developing children, adolescents, and adults (N = 180) whose mean ages were 11, 17, and 24 years, respectively. Each participant wrote an essay on the controversial topic of animals being trained to perform in circuses. Following this, the essays were examined in detail, focusing on selected aspects of syntactic, semantic, and pragmatic development. RESULTS: Performance improved in each of these domains during the years between childhood and adulthood. Age-related changes included gradual increases in essay length; mean length of utterance; relative clause production; and the use of literate words, including adverbial conjuncts (e.g., typically, however, finally), abstract nouns (e.g., longevity, respect, kindness), and metalinguistic and metacognitive verbs (e.g., reflect, argue, disagree). In addition, older writers produced a greater number of different reasons in their essays and were more likely to acknowledge diverse points of view as compared to younger writers, thereby evidencing greater flexibility of thought. CLINICAL IMPLICATIONS: The study offers useful implications for speech-language pathologists and classroom teachers working together to improve students' persuasive writing skills. Suggestions are offered for ways to accomplish this by focusing on key aspects of later language development in the areas of syntax, semantics, and pragmatics.

Adolescent↗

PubMed2006

Effects of increasing sound pressure level on lip and jaw movement parameters and consistency in young adults.

PURPOSE: Examination of movement parameters and consistency has been used to infer underlying neural control of movement. However, there has been no systematic investigation of whether the way individuals are asked (or cued) to increase loudness alters articulation. This study examined whether different cues to elicit louder speech induce different lip and jaw movement parameters or consistency. METHOD: Thirty healthy young adults produced two sentences (a) at comfortable loudness, (b) while targeting 10 dB SPL above comfortable loudness on a sound level meter, (c) at twice their perceived comfortable loudness, and (d) while multitalker noise was played in the background. Lip and jaw kinematics and acoustic measurements were taken. RESULTS: Each of the loud conditions resulted in a similar amount of SPL increase, about 10 dB. Speech rate was slower in the background noise condition. Changes to movement parameters and consistency (relative to comfortable) were different in the targeting condition as compared to the other loud conditions. CONCLUSIONS: The cues elicited different task demands, and therefore, different movement patterns were used by the speakers to achieve the target of increased loudness. Based on these results, cueing should be considered when eliciting increased vocal loudness in both clinical and research situations.

Adult↗

PubMed1981

Performance of children with normal and impaired oral language production on a set of auditory comprehension tests.

The purpose of this study was to investigate the comprehension abilities of children with impaired expressive language and to obtain information on the interrelationships among tests of comprehension. Forty preschool children, 20 with normal language and 20 with impaired expressive language, were given a set of auditory comprehension tests. As a group, the language-impaired children demonstrated deficits in comprehension when compared to the normal-language children. However, both groups scored near the ceiling on several tests, and on most tests that did differentiate the two groups, the mean scores of both groups when applied to performances of middle-class white children. An analysis of responses to selected groupings of analogous items revealed that a preschool child's correct response to a linguistic stimulus in one instance provides no assurance that the child will respond similarly to the stimulus in another linguistic environment with different task demands and different foil alternatives. In addition, the large majority of correlations among the test were nonsignificant, indicating that it is not clinically appropriate to regard these measures of language comprehension as equivalent.

Child↗

PubMed1988

Task-specific organization of activity in human jaw muscles.

Coordination of jaw muscle activity for speech production sometimes has been modeled using nonspeech behaviors. This orientation has been especially true in representations of mandibular movement in which the synergy of jaw muscles for speech production has been suggested to be derived from the central pattern generator (CPG) for chewing. The present investigation compared the coordination of EMG activity in mandibular muscles over a range of speech and nonspeech tasks. Results of a cross-correlational analysis between EMG signals demonstrated that the muscle synergies of the mandibular system depend on task demands. Contrary to some of the models discussed, continuous speech production yielded activation patterns that were clearly not related to coordinative patterns generated by the chewing CPG.

Adult↗

PubMed2003

The validity of self-reports of alcohol consumption: state of the science and challenges for research.

AIMS: To review three topics pertaining to the validity of alcohol self-reports: factors that influence response accuracy; the relative merits of different self-report approaches; and the utility of using alternative measures to confirm verbal reports. FINDINGS: Response behavior is influenced by the interaction of social context factors, respondent characteristics, and task attributes. Although research has advanced our knowledge about self-report methods, many questions remain unanswered. In particular, there is a need to investigate how task demands interact with different patterns of drinking behavior to affect response accuracy. There is also a continuing need to use multiple data sources to examine the extent of self-report response bias, and to determine whether it varies as a function of respondent characteristics or assessment timing. CONCLUSION: Self-report methods offer a reliable and valid approach to measuring alcohol consumption. The accuracy of such methods, however, can be improved by research directed at understanding the processes involved in response behavior.

Alcohol Drinking↗

PubMed2002

Can maternal depression increase infant risk of illness and growth impairment in developing countries?

Despite relative improvement in living conditions and availability of modern healthcare, infant mortality rates continue to be very high in many developing countries. High rates of depression have also been reported in women in these countries. The continuous care and attention of children is a demanding task, and poor physical or mental health in mothers might be expected to have adverse consequences on their children's health, nutrition and psychological well-being. Review of published literature reveals very little research in developing countries on the association between poor mental health in mothers and the subsequent physical well-being of their children. We hypothesize that the level of care provided by mothers with depression may put their infants at higher risk of infection and impaired growth, compared with infants of mothers without depression. We outline approaches to test such a hypothesis in a developing country, and discuss its implications.

Adult↗

PubMed1995

Changes in student learning styles and adaptive learning competencies following a senior preceptorship experience.

The purpose of this pre-post comparison study was to examine the effect of the preceptorship experience on the learning styles (the manner in which individuals process information from the environment), adaptive competencies (the congruences between personal skills and task demands) and environmental press perceptions (the subjects' perceptions of the importance of each adaptive competency to effective functioning in a designated environment) of 37 fourth-year baccalaureate nursing students. Using Kolb's theory of experiential learning as the theoretical framework for the study, it was found that the students' learning styles were inconsistently categorized by two versions of Kolb's learning style inventory. The preceptorship experience was perceived by students to have significantly (P < 0.05) improved the development of their adaptive learning competencies. Students perceived the importance of divergent, accommodative and convergent learning competencies to be lower after the preceptorship experience, with the only significant difference (P < 0.05) being between pre- and post-convergent competencies. The preceptorship experience, however, was found to contribute significantly more (P < 0.001) to the students' development of most adaptive competencies than their weekly clinical experiences. The findings support the notion that a senior preceptorship programme is a valuable and worthwhile learning experience to include in baccalaureate nursing curricula.

Adult↗

PubMed1999

'Listen, listen trust your own strange voice' (psychoanalytically informed conversations with a woman suffering serious illness).

This paper argues that the authentic voice of suffering can be denied to people with serious illness. Anguish and expressions of grief are sometimes replaced by joviality. Amid suffering, voices of anguish become strange inner voices that challenge defences of cheeriness and so are avoided, go unheard or are ignored. Bolstered by the everydayness of ward events and hospital life, suppression, repression and denial mean that people with serious illness can suffer without a voice. Listening to others requires the ability to listen to one's own inner voices and recognize how they might guide exchanges. By avoiding conducting conversations in ways dictated by our own fears, worries and fantasies we can listen, and in doing so allow shifts in awareness. Silent suffering can change to expressive suffering allowing a person to reach an autonomous self and so an authentic voice. The seriousness of a situation can be grasped and so life appreciated for what it is. Decisions can be made, business finished and relationships esteemed or otherwise. Through the format of brief therapeutic conversations, listening has a role to play in helping people with serious illness discover their autonomous and authentic voice. The discussion concludes with the suggestion that the need for throughput and roles and tasks demanded on nurses in general settings limits time and resources, and so liaison mental health nursing has a role to play. A specialist practitioner might offer conversational therapies, support nursing and medical staff and teach psychological concepts, thus contributing to an environment in which uncertainty is tolerated.

Defense Mechanisms↗

PubMed2000

The development and evaluation of a health education programme for pregnant women in a regional hospital, southern Thailand.

The maternal mortality rate (MMR) in Thailand is higher than neighbouring developing countries including Malaysia and Singapore. The 1993 MMR of Thailand was 249 per 100 000 livebirths which was four times higher than the rates in Malaysia and Singapore (World Health Organization 1995). The major causes of these deaths were haemorrhage, toxaemia of pregnancy and sepsis which were likely to be prevented by adequate prenatal care (Thailand Ministry of Public Health 1996). A large proportion of Thai pregnant women have poor health. Between 1994 and 1995, a national study conducted by Thailand Ministry of Health showed that 39% of pregnant women were anaemic, defined as haemoglobin concentration lower than 33% (Supamethaporn 1997). Another study conducted in the southern region also indicated that 13.8% of pregnant women were anaemic caused by iron deficiency (Phatthanapreechakul et al. 1997). Other behaviours which increased risks associated with child birth included non-antenatal care (ANC) attendance, undertaking physically demanding tasks and failure to increase nutritional intake during their pregnancy period (N. Phiriyanuphong et al. 1992, unpublished report). These factors emphasize the importance of a health education programme which could facilitate women to, for example, increase protein and iron intake during pregnancy which would reduce complications from their poor health status. This study was conducted in a regional hospital in Thailand where there was no systematic and well-planned health education programme for pregnant women. The initial aim was to design a health education programme using input from the hospital health care professionals including obstetricians, nurses, nutritionists, health educators and health promoters. An active involvement of these personnel assisted to sustain the provision of the programme provided for pregnant women after the cessation of the study project. Another aim of the study was to evaluate the outcomes of the programme using a pre-test-post-test method among selected pregnant women who participated in the newly designed health education programme.

Curriculum↗