796 research outputs found
No binocular rivalry in the LGN of alert macaque monkeys
AbstractOrthogonal drifting gratings were presented binocularly to alert macaque monkeys in an attempt to find neural correlates of binocular rivalry. Gratings were centered over lateral geniculate nucleus (LGN) receptive fields and the corresponding points for the opposite eye. The only task of the monkey was to fixate. We found no difference between the responses of LGN neurons under rivalrous and nonrivalrous conditions, as determined by examining the ratios of their respective power spectra. There was, however, a curious “temporal afterimage” effect in which cell responses continued to be modulated at the drift frequency of the grating for several seconds after the grating disappeared
Nine Criteria for a Measure of Scientific Output
Scientific research produces new knowledge, technologies, and clinical treatments that can lead to enormous returns. Often, the path from basic research to new paradigms and direct impact on society takes time. Precise quantification of scientific output in the short-term is not an easy task but is critical for evaluating scientists, laboratories, departments, and institutions. While there have been attempts to quantifying scientific output, we argue that current methods are not ideal and suffer from solvable difficulties. Here we propose criteria that a metric should have to be considered a good index of scientific output. Specifically, we argue that such an index should be quantitative, based on robust data, rapidly updated and retrospective, presented with confidence intervals, normalized by number of contributors, career stage and discipline, impractical to manipulate, and focused on quality over quantity. Such an index should be validated through empirical testing. The purpose of quantitatively evaluating scientific output is not to replace careful, rigorous review by experts but rather to complement those efforts. Because it has the potential to greatly influence the efficiency of scientific research, we have a duty to reflect upon and implement novel and rigorous ways of evaluating scientific output. The criteria proposed here provide initial steps toward the systematic development and validation of a metric to evaluate scientific output
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A Refined Neuronal Population Measure of Visual Attention
Neurophysiological studies of cognitive mechanisms such as visual attention typically ignore trial-by-trial variability and instead report mean differences averaged across many trials. Advances in electrophysiology allow for the simultaneous recording of small populations of neurons, which may obviate the need for averaging activity over trials. We recently introduced a method called the attention axis that uses multi-electrode recordings to provide estimates of attentional state of behaving monkeys on individual trials. Here, we refine this method to eliminate problems that can cause bias in estimates of attentional state in certain scenarios. We demonstrate the sources of these problems using simulations and propose an amendment to the previous formulation that provides superior performance in trial-by-trial assessments of attentional state
Correlation Between Voice And Life Quality And Occupation
Dysphonia may impair the quality of communication and social relations of people, thereby direcdy affecting quality of life. It is common knowledge amongst professionals involved with the treatment of voice disorders the need for objective protocols to evaluate voice quality and measure its impact on the individual's quality of life. Aim: To associate life quality with the degree of dysphonia and professional voice use in a group of dysphonic patients. Materials and Methods: A prospective clinical study was undertaken with a group of dysphonic patients using an internationally validated voice-related quality-of-life protocol. A statistical analysis of the results was carried out, not distinguishing between those who use their voices professionally and those who don't. Results: dysphonia had an impact on the quality of life of all patients. There was no statistically significant difference between the groups - professional users and non-users of their voices; however, considering the groups separately, this correlation was significant only in the group of patients who do not use their voices professionally. Conclusion: Dysphonia affected the quality of life of all subjects regardless of their voice use.752275279Wilson, J.A., Deary, I.J., Millar, A., Mackenzie, K., The quality of life impact of dysphonia (2002) Clinical Otolaryngology and Allied Sciences, 27 (3), pp. 179-182. , DOI 10.1046/j.1365-2273.2002.00559.xThe world health organization quality of life assessment (WHOQOL): Position paper from the world health organization (1995) Soc Sci Med, 41 (10), pp. 1403-1409. , The WHOQOL Group 1995. OxfordBerlim, M.T., Fleck, M.P.A., Quality of life: A brand new concept for research and practice in psychiatry (2003) Revista Brasileira de Psiquiatria, 25 (4), pp. 249-252Jacobson, B.H., Johnson, A., Grywalsky, C., Silbergleit, A., Jacobson, G., Benninger, M.S., The voice handicap index: Development and validation (1996) Am J Speech Lang Pathol, 6 (3), pp. 66-70. , RockvilleBehlau, M., Madazio, G., Feijó, D., Pontes, P., Avaliação de voz (2001) Voz: O Livro Do Especialista, 1, pp. 121-124. , Behlau: Rio de Janeiro: RevinterHogikyan, N.D., Sethuraman, G., Validation of an instrument to measure voice-related quality of life (V- RQOL) (1999) Journal of Voice, 13 (4), pp. 557-569Dejonckere, P.H., Bradley, P., Clemente, P., Cornut, G., Crevier-Buchman, L., Friedrich, G., Van De Heyning, P., Woisard, V., A basic protocol for functional assessment of voice pathology, especially for investigating the efficacy of (phonosurgical) treatments and evaluating new assessment techniques: Guideline elaborated by the Committee on Phoniatrics of the European Laryngological Society (ELS) (2001) European Archives of Oto-Rhino-Laryngology, 258 (2), pp. 77-82. , DOI 10.1007/s004050000299Rasch, T., Gunther, S., Hoppe, U., Eysholdt, U., Rosanowski, F., Voice-related quality of life in organic and functional voice disorders (2005) Logopedics Phoniatrics Vocology, 30 (1), pp. 9-13. , DOI 10.1080/14015430510006640Krischke, S., Weigelt, S., Hoppe, U., Kollner, V., Klotz, M., Eyshouldt, U., Quality of life in dysphonic patients (2004) J Voice, 19 (1), pp. 132-137Kasama, S.T., Brasolotto, A.G., Vocal perception and quality of life (2007) Pro Fono, 19 (1), pp. 19-28. , original titleMurry, T., Medrado, R., Hogikyan, N.D., Aviv, J.E., The relationship between ratings of voice quality and quality of life measures (2004) Journal of Voice, 18 (2), pp. 183-192. , DOI 10.1016/j.jvoice.2003.11.003, PII S0892199703001607Behlau, M., Hogikyan, N.D., Gasparini, G., Quality of life and voice: Study of a Brazilian population using the voice-related quality of life measure (2007) Folia Phoniatrica et Logopaedica, 59 (6), pp. 286-296. , DOI 10.1159/00010833
Management practices as risk factors for the presence of bulk milk antibodies to Salmonella, Neospora caninum and Leptospira interrogans serovar hardjo in Irish dairy herds
peer-reviewedA survey of management practices in 309 Irish dairy herds was used to identify risk factors for the presence of antibodies to Salmonella, Neospora caninum and Leptospira interrogans serovar hardjo in extensively managed unvaccinated dairy herds. A previous study documented a herd-level seroprevalence in bulk milk of 49%, 19% and 86% for Salmonella, Neospora caninum and leptospira interrogans serovar hardjo, respectively in the unvaccinated proportion of these 309 herds in 2009. Association analyses in the present study were carried out using multiple logistic regression models. Herds where cattle were purchased or introduced had a greater likelihood of being positive to leptospira interrogans serovar hardjo (P<0.01) and Salmonella (P<0.01). Larger herds had a greater likelihood of recording a positive bulk milk antibody result to leptospira interrogans serovar hardjo (P<0.05). Herds that practiced year round calving were more likely to be positive to Neospora caninum (P<0.05) compared to herds with a spring-calving season, with no difference in risk between herds that practiced split calving compared to herds that practiced spring calving. No association was found between presence of dogs on farms and prevalence of Neospora caninum possibly due to limited access of dogs to infected materials including afterbirths. The information from this study will assist in the design of suitable control programmes for the diseases under investigation in pasture-based livestock systems
A Normalization Model of Attentional Modulation of Single Unit Responses
Although many studies have shown that attention to a stimulus can enhance the responses of individual cortical sensory neurons, little is known about how attention accomplishes this change in response. Here, we propose that attention-based changes in neuronal responses depend on the same response normalization mechanism that adjusts sensory responses whenever multiple stimuli are present. We have implemented a model of attention that assumes that attention works only through this normalization mechanism, and show that it can replicate key effects of attention. The model successfully explains how attention changes the gain of responses to individual stimuli and also why modulation by attention is more robust and not a simple gain change when multiple stimuli are present inside a neuron's receptive field. Additionally, the model accounts well for physiological data that measure separately attentional modulation and sensory normalization of the responses of individual neurons in area MT in visual cortex. The proposal that attention works through a normalization mechanism sheds new light a broad range of observations on how attention alters the representation of sensory information in cerebral cortex
Motor Preparatory Activity in Posterior Parietal Cortex is Modulated by Subjective Absolute Value
For optimal response selection, the consequences associated with behavioral success or failure must be appraised. To determine how monetary consequences influence the neural representations of motor preparation, human brain activity was scanned with fMRI while subjects performed a complex spatial visuomotor task. At the beginning of each trial, reward context cues indicated the potential gain and loss imposed for correct or incorrect trial completion. FMRI-activity in canonical reward structures reflected the expected value related to the context. In contrast, motor preparatory activity in posterior parietal and premotor cortex peaked in high “absolute value” (high gain or loss) conditions: being highest for large gains in subjects who believed they performed well while being highest for large losses in those who believed they performed poorly. These results suggest that the neural activity preceding goal-directed actions incorporates the absolute value of that action, predicated upon subjective, rather than objective, estimates of one's performance
Results of a phase I/II multi-center investigation of udenafil in adolescents after fontan palliation
BACKGROUND:
The Fontan operation results in a circulation that is dependent on low pulmonary vascular resistance to maintain an adequate cardiac output. Medical therapies that lower pulmonary vascular resistance may augment cardiac output and improve long-term outcomes.
OBJECTIVES:
This phase I/II clinical trial conducted by the Pediatric Heart Network was designed to evaluate short-term safety, pharmacokinetics (PK), and preliminary efficacy of udenafil in adolescents following Fontan.
METHODS:
A 5-day dose-escalation trial was conducted in five study cohorts of six subjects each (37.5, 87.5, and 125 mg daily, 37.5 and 87.5 mg by mouth twice daily). A control cohort with 6 subjects underwent exercise testing only. Adverse events (AEs) were recorded, PK samples were collected on study days six through eight, and clinical testing was performed at baseline and day five.
RESULTS:
The trial enrolled 36 subjects; mean age 15.8 years (58% male). There were no significant differences in subject characteristics between cohorts. No drug-related serious AEs were reported during the study period; 24 subjects had AEs possibly or probably related to study drug. Headache was the most common AE, occurring in 20 of 30 subjects. The 87.5 mg bid cohort was well tolerated, achieved the highest maximal concentration (506 ng/mL) and the highest average concentration over the dosing interval (279 ng/mL), and was associated with a suggestion of improvement in myocardial performance. Exercise performance did not improve in any of the dosing cohorts.
CONCLUSIONS:
Udenafil was well-tolerated at all dosing levels. The 87.5 mg bid cohort achieved the highest plasma drug level and was associated with a suggestion of improvement in myocardial performance. These data suggest that the 87.5 mg bid regimen may be the most appropriate for a Phase III clinical trial
Imbedding HACCP principles in dairy herd health and production management: case report on calf rearing
Driven by consumer demands, European legislation has suggested the use of HACCP (Hazard Analysis Critical Control Point) as the quality risk management programme for the whole dairy chain. Until now, an exception has been made for primary producers, but as regulations evolve, on-farm HACCP-like programmes should be ready to assure food safety as well as animal health and animal welfare. In our field experiment, the HACCP-concept was used to combine both optimal farm management and formalisation of quality assurance in an on-farm situation in the Netherlands. The process of young stock rearing was chosen, since its importance for the future of the farm is often underestimated. Hazards and their associated risk factors can be controlled within the farm-specific standards and tolerances, as targets can be controlled by corrective measures and by implementation of farm-specific worksheets. The veterinarian is pivotal for the facility-based HACCP team, since he/she has knowledge about on-farm risk assessment and relations between clinical pathology, feed and farm management. The HACCP concept in combination with veterinary herd health and production management programmes offers a promising approach to optimise on-farm production processes (i.e., young stock rearing) in addition to a structural approach for quality risk management on dairy farms
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