830 research outputs found

    The Brain Differentially Prepares Inner and Overt Speech Production: Electrophysiological and Vascular Evidence

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    Speech production not only relies on spoken (overt speech) but also on silent output (inner speech). Little is known about whether inner and overt speech are processed differently and which neural mechanisms are involved. By simultaneously applying electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS), we tried to disentangle executive control from motor and linguistic processes. A preparation phase was introduced additionally to the examination of overt and inner speech directly during naming (i.e., speech execution). Participants completed a picture-naming paradigm in which the pure preparation phase of a subsequent speech production and the actual speech execution phase could be differentiated. fNIRS results revealed a larger activation for overt rather than inner speech at bilateral prefrontal to parietal regions during the preparation and at bilateral temporal regions during the execution phase. EEG results showed a larger negativity for inner compared to overt speech between 200 and 500 ms during the preparation phase and between 300 and 500 ms during the execution phase. Findings of the preparation phase indicated that differences between inner and overt speech are not exclusively driven by specific linguistic and motor processes but also impacted by inhibitory mechanisms. Results of the execution phase suggest that inhibitory processes operate during phonological code retrieval and encoding

    Future changes in North Atlantic winter cyclones in CESM-LE – Part 1: Cyclone intensity, potential vorticity anomalies, and horizontal wind speed

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    Strong low-level winds associated with extratropical cyclones can have substantial impacts on society. The wind intensity and the spatial distribution of wind maxima may change in a warming climate; however, the involved changes in cyclone structure and dynamics are not entirely clear. Here, such structural changes of strong North Atlantic cyclones in a warmer climate close to the end of the current century are investigated with storm-relative composites based on Community Earth System Model Large Ensemble (CESM-LE) simulations. Furthermore, a piecewise potential vorticity inversion is applied to associate such changes in low-level winds to changes in potential vorticity (PV) anomalies at different levels. Projected changes in cyclone intensity are generally rather small. However, using cyclone-relative composites, we identify an extended wind footprint southeast of the center of strong cyclones, where the wind speed tends to intensify in a warmer climate. Both an amplified low-level PV anomaly driven by enhanced diabatic heating and a dipole change in upper-level PV anomalies contribute to this wind intensification. On the contrary, wind changes associated with lower- and upper-level PV anomalies mostly compensate for each other upstream of the cyclone center. Wind changes at upper levels are dominated by changes in upper-level PV anomalies and the background flow. Altogether, our results indicate that a complex interaction of enhanced diabatic heating and altered non-linear upper-tropospheric wave dynamics shape future changes in near-surface winds in North Atlantic cyclones

    Unravelling the transport of moisture into the Saharan Air Layer using passive tracers and isotopes

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    The subtropical free troposphere plays a critical role in the radiative balance of the Earth. However, the complex interactions controlling moisture in this sensitive region and, in particular, the relative importance of long-range transport compared to lower-tropospheric mixing, remain unclear. This study uses the regional COSMO model equipped with stable water isotopes and passive water tracers to quantify the contributions of different evaporative sources to the moisture and its stable isotope signals in the eastern subtropical North Atlantic free troposphere. In summer, this region is characterized by two alternating large-scale circulation regimes: (i) dry, isotopically depleted air from the upper-level extratropics, and (ii) humid, enriched air advected from Northern Africa within the Saharan Air Layer (SAL) consisting of a mixture of moisture of diverse origin (tropical and extratropical North Atlantic, Africa, Europe, the Mediterranean). This diversity of moisture sources in regime (ii) arises from the convergent inflow at low levels of air from different neighbouring regions into the Saharan heat low (SHL), where it is mixed and injected by convective plumes into the large-scale flow aloft, and thereafter expelled to the North Atlantic within the SAL. Remarkably, this regime is associated with a large contribution of moisture that evaporated from the North Atlantic, which makes a detour through the SHL and eventually reaches the 850–550 hPa layer above the Canaries. Moisture transport from Europe via the SHL to the same layer leads to the strongest enrichment in heavy isotopes (δ2H correlates most strongly with this tracer). The vertical profiles over the North Atlantic show increased humidity and δ2H and reduced static stability in the 850–550 hPa layer, and smaller cloud fraction in the boundary layer in regime (ii) compared to regime (i), highlighting the key role of moisture transport through the SHL in modulating the radiative balance in this region

    Prioritarian rates of return to antipoverty transfers

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    A growing impact evaluation literature on antipoverty transfer programmes in low- and middle-income countries measures changes in utilitarian terms, at their unit value. The paper argues that valuing antipoverty transfers is more appropriately done within a framework of prioritarian social welfare functions, as the very presence of these programmes indicates that polities place a greater value on gains and losses among the disadvantaged. The paper applies this framework to the Senior Citizen Grant in Uganda, including survey and experimental work throwing light on social preferences for redistribution. It finds that default utilitarian valuation significantly underestimates the social value of transfer programmes

    Pragmatisch-kommunikative Störungen – Herausforderungen für Sprachheilpädagogik und Sprachtherapie in Schule und Berufsbildung

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    Die Frage nach der Partizipation/Teilhabe von Kindern und Jugendlichen mit sprachlichen Beeinträchtigungen ist häufig auch mit ihren pragmatisch-kommunikativen Fähigkeiten verknüpft. Dabei beinhaltet ein kompetentes Sprachhandeln unterschiedliche Teilfähigkeiten und Kompetenzen, welche sprachliche, aber auch soziale, kognitive, kulturelle und emotionale Aspekte beinhalten. Dieses interdisziplinäre Themenfeld verlangt nach einer multiprofessionellen Unterstützung von Kindern und Jugendlichen mit eingeschränkten pragmatisch-kommunikativen Fähigkeiten. (DIPF/Orig.

    Effects of team leaders' position in cardiopulmonary resuscitation teams on leadership behavior and team performance: A prospective randomized interventional cross-over simulation-based trial.

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    BACKGROUND Leadership is an important performance factor in resuscitation teams. Medical guidelines for cardiopulmonary resuscitation (CPR) advise team leaders to keep hands off patients. There is little evidence for this recommendation that is based purely on observational data. Accordingly, the aim of this trial was to investigate the effect of leaders' position during CPR on leadership behavior and team performance. METHOD This is a prospective randomized interventional crossover simulation-based single center trial. Teams of 3 to 4 physicians each, representing a rapid response team, were confronted with a simulated cardiac arrest. Team leaders were randomly assigned and assigned team leaders were 1:1 randomized to 2 leadership positions: position at the patient's head; and hands-off position. Data analysis was performed from video-recordings. All utterances during the first 4 minutes of CPR were transcribed and coded based on a modified "Leadership Description Questionnaire." The primary endpoint was the number of leadership statements. Secondary outcomes included CPR related performance markers like hands-on time and chest compression rate, and the behavioral related endpoints Decision Making, Error Detection, and Situational Awareness. RESULTS Data from 40 teams (143 participants) was analyzed. Leaders in hands-off position made more leadership statements (28 ± 8 vs 23 ± 8; P <.01) and contributed more to their team's leadership (59 ± 13% vs 50 ± 17%; P = .01) than leaders in the head position. Leaders' position had no significant effect on their teams' CPR performance, Decision Making, and Error Detection. Increased numbers of leadership statements lead to improved hands-on time ( R = 0.28; 95% confidence interval 0.05-0.48; P = .02). CONCLUSIONS Team leaders in a hands-off position made more leadership statements and contributed more to their teams' leadership during CPR than team leaders actively involved in the head position. However, team leaders' position had no effect on their teams' CPR performance

    CO2 exchange of a temperate fen during the conversion from moderately rewetting to flooding

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    Author Posting. © American Geophysical Union, 2013. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Biogeosciences 118 (2013): 940–950, doi:10.1002/jgrg.20069.Year-round flooding provides a common land management practice to reestablish the natural carbon dioxide (CO2) sink function of drained peatlands. Here we present eddy covariance measurements of net CO2 exchange from a temperate fen during three consecutive growing seasons (May–October) that span a period of conversion from moderately rewetting to flooding. When we started our measurements in 2009, the hydrological conditions were representative for the preceding 20 years with a mean growing season water level (MWGL) of 0 cm but considerably lower water levels in summer. Flooding began in 2010 with an MWGL of 36 cm above the surface. The fen was a net CO2 sink throughout all growing seasons (2009: −333.3 ± 12.3, 2010: −294.1 ± 8.4, 2011: −352.4 ± 5.1 g C m−2), but magnitudes of canopy photosynthesis (CP) and ecosystem respiration (Reco) differed distinctively. Rates of CP and Reco were high before flooding, dropped by 46% and 61%, respectively, in 2010, but increased again during the beginning of growing season 2011 until the water level started to rise further due to strong rainfalls during June and July. We assume that flooding decreases not only the CO2 release due to inhibited Reco under anaerobic conditions but also CO2 sequestration rates are constricted due to decreased CP. We conclude that rewetting might act as a disturbance for a plant community that has adapted to drier conditions after decades of drainage. However, if the recent species are still abundant, a rise in CP and autotrophic Reco can be expected after plants have developed plastic response strategies to wetter conditions.F.K. was supported by a scholarship of the Federal State of Mecklenburg-Western Pomerania and by the German Research Foundation (DFG). The German Academic Exchange Service (DAAD) funded the collaboration with I.F.2013-12-2

    Correlation of Postoperative Imaging With MRI and Clinical Outcome After Cartilage Repair of the Ankle: A Systematic Review and Meta-analysis

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    BACKGROUND Magnetic resonance imaging (MRI) is commonly used for evaluation of ankle cartilage repair, yet its association with clinical outcome is controversial. This study analyzes the correlation between MRI and clinical outcome after cartilage repair of the talus including bone marrow stimulation, cell-based techniques, as well as restoration with allo- or autografting. METHODS A systematic search was performed in MEDLINE, Embase, and Cochrane Collaboration. Articles were screened for correlation of MRI and clinical outcome. Guidelines of Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) were used. Chi-square test and regression analysis were performed to identify variables that determine correlation between clinical and radiologic outcome. RESULTS Of 2687 articles, a total of 43 studies (total 1212 cases) were included with a mean Coleman score of 57 (range, 33-70). Overall, 93% were case series, and 5% were retrospective and 2% prospective cohort studies. Associations between clinical outcome and ≥1 imaging variable were found in 21 studies (49%). Of 24 studies (56%) using the composite magnetic resonance observation of cartilage repair tissue (MOCART) score, 7 (29%) reported a correlation of the composite score with clinical outcome. Defect fill was associated with clinical outcome in 5 studies (12%), and 5 studies (50%) reported a correlation of T2 mapping and clinical outcome. Advanced age, shorter follow-up, and larger study size were associated with established correlation between clinical and radiographic outcome (P = .021, P = .028, and P = .033). CONCLUSION Interpreting MRI in prediction of clinical outcome in ankle cartilage repair remains challenging; however, it seems to hold some value in reflecting clinical outcome in patients with advanced age and/or at a shorter follow-up. Yet, further research is warranted to optimize postoperative MRI protocols and assessments allowing for a more comprehensive repair tissue evaluation, which eventually reflect clinical outcome in patients after cartilage repair of the ankle.Level of Evidence: Level III, systematic review and meta-analysis

    Perceived stress and team performance during a simulated resuscitation

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    Purpose: Barriers to optimal performance of cardiopulmonary resuscitation may partly relate to human factors, such as stress and specific emotions. The aim of this study was to investigate whether mental stress and different perceived emotions have a negative impact on the performance of rescuers. Methods: This prospective, observational study was conducted at the Simulator Center of the University Hospital Basel, Switzerland. A total of 120 medical students (70% female) participated in teams of three. They reported levels of perceived stress, feeling overwhelmed, motivation and specific emotions before, during, and after a simulated resuscitation. The association of stress/overload (index of stress and feeling overwhelmed), motivation, and specific emotions with resuscitation performance defined as hands-on time during the first 180s after cardiac arrest was investigated. Results: During resuscitation, levels of stress/overload, motivation, and negative emotions were significantly higher as compared to the periods before and after resuscitation. In contrast, positive emotions were highest before and after resuscitation and significantly lower during resuscitation. In general, females reported higher stress/overload and negative emotions, whereas males reported more positive emotions. A multivariate linear regression model showed negative associations of stress/overload (regression coefficient −18.12, 95% CI −30.73, −5.51, p=0.006) and positive associations of motivation (regression coefficient 13.45, 95% CI 0.95, 25.95, p=0.036) with resuscitation performance. Conclusion: A simulated cardiac arrest caused substantial perceived stress/overload and negative emotions, particularly in female students, which adversely impacted resuscitation performance. Further studies are required to expand our findings to more experienced medical professionals and investigate whether stress coping strategies improve resuscitation performanc
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