259 research outputs found
Reading between Eye Saccades
Background: Skilled adult readers, in contrast to beginners, show no or little increase in reading latencies as a function of the number of letters in words up to seven letters. The information extraction strategy underlying such efficiency in word identification is still largely unknown, and methods that allow tracking of the letter information extraction through time between eye saccades are needed to fully address this question. Methodology/Principal Findings: The present study examined the use of letter information during reading, by means of the Bubbles technique. Ten participants each read 5,000 five-letter French words sampled in space-time within a 200 ms window. On the temporal dimension, our results show that two moments are especially important during the information extraction process. On the spatial dimension, we found a bias for the upper half of words. We also show for the first time that letter positions four, one, and three are particularly important for the identification of five-letter words. Conclusions/Significance: Our findings are consistent with either a partially parallel reading strategy or an optimal serial reading strategy. We show using computer simulations that this serial reading strategy predicts an absence of a wordlength effect for words from four- to seven letters in length. We believe that the Bubbles technique will play an importan
Deuteron life-time in hot and dense nuclear matter near equilibrium
We consider deuteron formation in hot and dense nuclear matter close to
equilibrium and evaluate the life-time of the deuteron fluctuations within the
linear response theory. To this end we derive a generalized linear Boltzmann
equation where the collision integral is related to equilibrium correlation
functions. In this framework we then utilize finite temperature Green functions
to evaluate the collision integrals. The elementary reaction cross section is
evaluated within the Faddeev approach that is suitably modified to reflect the
properties of the surrounding hot and dense matter.Comment: 15 pages, 5 figure
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Specific detection of methionine 27 mutation in histone 3 variants (H3K27M) in fixed tissue from high-grade astrocytomas
Studies in pediatric high-grade astrocytomas (HGA) by our group and others have uncovered recurrent somatic mutations affecting highly conserved residues in histone 3 (H3) variants. One of these mutations leads to analogous p.Lys27Met (K27M) mutations in both H3.3 and H3.1 variants, is associated with rapid fatal outcome, and occurs specifically in HGA of the midline in children and young adults. This includes diffuse intrinsic pontine gliomas (80 %) and thalamic or spinal HGA (>90 %), which are surgically challenging locations with often limited tumor material available and critical need for specific histopathological markers. Here, we analyzed formalin-fixed paraffin-embedded tissues from 143 pediatric HGA and 297 other primary brain tumors or normal brain. Immunohistochemical staining for H3K27M was compared to tumor genotype, and also compared to H3 tri-methylated lysine 27 (H3K27me3) staining, previously shown to be drastically decreased in samples carrying this mutation. There was a 100 % concordance between genotype and immunohistochemical analysis of H3K27M in tumor samples. Mutant H3K27M was expressed in the majority of tumor cells, indicating limited intra-tumor heterogeneity for this specific mutation within the limits of our dataset. Both H3.1 and H3.3K27M mutants were recognized by this antibody while non-neoplastic elements, such as endothelial and vascular smooth muscle cells or lymphocytes, did not stain. H3K27me3 immunoreactivity was largely mutually exclusive with H3K27M positivity. These results demonstrate that mutant H3K27M can be specifically identified with high specificity and sensitivity using an H3K27M antibody and immunohistochemistry. Use of this antibody in the clinical setting will prove very useful for diagnosis, especially in the context of small biopsies in challenging midline tumors and will help orient care in the context of the extremely poor prognosis associated with this mutation. Electronic supplementary material The online version of this article (doi:10.1007/s00401-014-1337-4) contains supplementary material, which is available to authorized users
Evaluation of the Total Design Method in a survey of Japanese dentists
BACKGROUND: This study assessed the application of the Total Design Method (TDM) in a mail survey of Japanese dentists. The TDM was chosen because survey response rates in Japan are unacceptably low and the TDM had previously been used in a general population survey. METHODS: Four hundred and seventy eight dentist members of the Okayama Medical and Dental Practitioner's Association were surveyed. The nine-page, 27-item questionnaire covered dentist job satisfaction, physical practice, and dentist and patient characteristics. Respondents to the first mailing or the one-week follow-up postcard were defined as early responders; others who responded were late responders. Responder bias was assessed by examining age, gender and training. RESULTS: The overall response rate was 46.7% (223/478). The response rates by follow-up mailing were, 18% after the first mailing, 35.4% after the follow-up postcard, 42.3% after the second mailing, and 46.7% after the third mailing. Respondents did not differ from non-respondents in age or gender, nor were there differences between early and late responders. CONCLUSION: The application of TDM in this survey of Japanese dentists produced lower rates of response than expected from previous Japanese and US studies
Effect of nitrous oxide on cisatracurium infusion demands: a randomized controlled trial
<p>Abstract</p> <p>Background</p> <p>Recent studies have questioned our previous understanding on the effect of nitrous oxide on muscle relaxants, since nitrous oxide has been shown to potentiate the action of bolus doses of mivacurium, rocuronium and vecuronium. This study was aimed to investigate the possible effect of nitrous oxide on the infusion requirements of cisatracurium.</p> <p>Methods</p> <p>70 ASA physical status I-III patients aged 18-75 years were enrolled in this randomized trial. The patients were undergoing elective surgery requiring general anesthesia with a duration of at least 90 minutes. Patients were randomized to receive propofol and remifentanil by target controlled infusion in combination with either a mixture of oxygen and nitrous oxide (Nitrous oxide/TIVA group) or oxygen in air (Air/TIVA group). A 0.1 mg/kg initial bolus of cisatracurium was administered before tracheal intubation, followed by a closed-loop computer controlled infusion of cisatracurium to produce and maintain a 90% neuromuscular block. Cumulative dose requirements of cisatracurium during the 90-min study period after bolus administration were measured and the asymptotic steady state rate of infusion to produce a constant 90% block was determined by applying nonlinear curve fitting to the data on the cumulative dose requirement during the study period.</p> <p>Results</p> <p>Controller performance, i.e. the ability of the controller to maintain neuromuscular block constant at the setpoint and patient characteristics were similar in both groups. The administration of nitrous oxide did not affect cisatracurium infusion requirements. The mean steady-state rates of infusion were 0.072 +/- 0.018 and 0.066 +/- 0.017 mg * kg-1 * h-1 in Air/TIVA and Nitrous oxide/TIVA groups, respectively.</p> <p>Conclusions</p> <p>Nitrous oxide does not affect the infusion requirements of cisatracurium.</p> <p>Trial registration</p> <p>ClinicalTrials.gov NCT01152905; European Clinical Trials Database at <url>http://eudract.emea.eu.int/2006-006037-41</url>.</p
Randomized pilot study to disseminate caries-control services in dentist offices
BACKGROUND: To determine whether education and financial incentives increased dentists' delivery of fluoride varnish and sealants to at risk children covered by capitation dental insurance in Washington state (U.S.). METHODS: In 1999, 53 dental offices in Washington Dental Service's capitation dental plan were invited to participate in the study, and consenting offices were randomized to intervention (n = 9) and control (n = 10) groups. Offices recruited 689 capitation children aged 6–14 and at risk for caries, who were followed for 2 years. Intervention offices received provider education and fee-for-service reimbursement for delivering fluoride varnish and sealants. Insurance records were used to calculate office service rates for fluoride, sealants, and restorations. Parents completed mail surveys after follow-up to measure their children's dental utilization, dental satisfaction, dental fear and oral health status. Regression models estimated differences in service rates between intervention and control offices, and compared survey measures between groups. RESULTS: Nineteen offices (34%) consented to participate in the study. Fluoride and sealant rates were greater in the intervention offices than the control offices, but the differences were not statistically significant. Restoration rates were lower in the intervention offices than the control offices. Parents in the intervention group reported their children had less dental fear than control group parents. CONCLUSION: Due to low dentist participation the study lacked power to detect an intervention effect on dentists' delivery of caries-control services. The intervention may have reduced children's dental fear
Deferred imitation and declarative memory in domestic dogs
This study demonstrates for the first time deferred imitation of novel actions in dogs (Canis familiaris) with retention intervals of 1.5 min and memory of familiar actions with intervals ranging from 0.40 to 10 min. Eight dogs were trained using the 'Do as I do' method to match their own behaviour to actions displayed by a human demonstrator. They were then trained to wait for a short interval to elapse before they were allowed to show the previously demonstrated action. The dogs were then tested for memory of the demonstrated behaviour in various conditions, also with the so-called two-action procedure and in a control condition without demonstration. Dogs were typically able to reproduce familiar actions after intervals as long as 10 min, even if distracted by different activities during the retention interval and were able to match their behaviour to the demonstration of a novel action after a delay of 1 min. In the two-action procedure, dogs were typically able to imitate the novel demonstrated behaviour after retention intervals of 1.5 min. The ability to encode and recall an action after a delay implies that facilitative processes cannot exhaustively explain the observed behavioural similarity and that dogs' imitative abilities are rather based on an enduring mental representation of the demonstration. Furthermore, the ability to imitate a novel action after a delay without previous practice suggests presence of declarative memory in dogs. © 2013 Springer-Verlag Berlin Heidelberg
Arrhythmogenic mechanisms in the isolated perfused hypokalaemic murine heart
AIM: Hypokalaemia is associated with a lethal form of ventricular tachycardia (VT), torsade de pointes, through pathophysiological mechanisms requiring clarification. METHODS: Left ventricular endocardial and epicardial monophasic action potentials were compared in isolated mouse hearts paced from the right ventricular epicardium perfused with hypokalaemic (3 and 4 mm [K(+)](o)) solutions. Corresponding K(+) currents were compared in whole-cell patch-clamped epicardial and endocardial myocytes. RESULTS: Hypokalaemia prolonged epicardial action potential durations (APD) from mean APD(90)s of 37.2 ± 1.7 ms (n = 7) to 58.4 ± 4.1 ms (n =7) and 66.7 ± 2.1 ms (n = 11) at 5.2, 4 and 3 mm [K(+)](o) respectively. Endocardial APD(90)s correspondingly increased from 51.6 ± 1.9 ms (n = 7) to 62.8 ± 2.8 ms (n = 7) and 62.9 ± 5.9 ms (n = 11) giving reductions in endocardial–epicardial differences, ΔAPD(90), from 14.4 ± 2.6 to 4.4 ± 5.0 and −3.4 ± 6.0 ms respectively. Early afterdepolarizations (EADs) occurred in epicardia in three of seven spontaneously beating hearts at 4 mm [K(+)](o) with triggered beats followed by episodes of non-sustained VT in nine of 11 preparations at 3 mm. Programmed electrical stimulation never induced arrhythmic events in preparations perfused with normokalemic solutions yet induced VT in two of seven and nine of 11 preparations at 4 and 3 mm [K(+)](o) respectively. Early outward K(+) current correspondingly fell from 73.46 ± 8.45 to 61.16±6.14 pA/pF in isolated epicardial but not endocardial myocytes (n = 9) (3 mm [K(+)](o)). CONCLUSIONS: Hypokalaemic mouse hearts recapitulate the clinical arrhythmogenic phenotype, demonstrating EADs and triggered beats that might initiate VT on the one hand and reduced transmural dispersion of repolarization reflected in ΔAPD(90) suggesting arrhythmogenic substrate on the other
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