1,389 research outputs found

    Cerebellar cortical AMPA/kainate receptor blockade prevents performance of classically conditioned nictitating membrane responses

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    Classical conditioning of the nictitating membrane-eye blink response of rabbits is a simple form of associative motor learning. Lesion studies have shown that performance of learned responses is dependent on the cerebellum, but they have not shown whether there is storage of memories within the cerebellum or distinguished the roles of the cerebellar cortex and nuclei. Reversible inactivations of the cerebellar nuclei have directly implicated the cerebellum in the acquisition of nictitating membrane conditioning, but previously the cerebellar cortex has not been reversibly inactivated to assess its contribution to the performance or acquisition of conditioned responses. Here we use the water-soluble disodium salt of 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) reversibly to block cerebellar cortical AMPA-kainate receptors in lobule HVI and quantitative autoradiography to map its distribution. Conditioned responses are completely, but reversibly, abolished for 10-60 min depending on the concentration of the CNQX infusion and its location within HVI. Zebrin immunohistochemistry was used to define the optimal cortical infusion site that, we suggest, corresponds to the location of the eye blink control regions. We confirm that areas in HVI are essential for the expression of classically conditioned nictitating membrane responses, and we establish a method to analyze the role of cerebellar cortex in the acquisition of this form of motor learning

    Low incidence of toxoplasma infection during pregnancy and in newborns in Sweden

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    To estimate the burden of disease due to congenital toxoplasmosis in Sweden the incidence of primary infections during pregnancy and birth prevalence of congenital toxoplasmosis in 40978 children born in two regions in Sweden was determined. Women possibly infected during pregnancy were identified based on: 1, detection of specific IgG based on neonatal screening of the phenylketonuria (PKU) card blood spot followed by retrospective testing of stored prenatal samples to detect women who acquired infection during pregnancy and follow up of their children to 12 months; 2, detection of specific IgM on the PKU blood spot. The birth prevalence of congenital toxoplasmosis was 0·73/10000 (95% CI 0·15–2·14) (3/40978). The incidence of primary infection during pregnancy was 5·1/10000 (95% CI 2·6–8·9) susceptible pregnant women. The seroprevalence in the southern part was 25·7% and in the Stockholm area 14·0%. The incidence of infection during pregnancy was low, as the birth prevalence of congenital toxoplasmosis. Neonatal screening warrants consideration in view of the low cost and feasibility

    Sedimentary mechanisms of a modern banded iron formation on Milos Island, Greece

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    An Early Quaternary shallow submarine hydrothermal iron formation (IF) in the Cape Vani sedimentary basin (CVSB) on Milos Island, Greece, displays banded rhythmicity similar to Precambrian banded iron formation (BIF). Sedimentary, stratigraphic reconstruction, biogeochemical analysis and micro-nanoscale mineralogical characterization confirms the Milos rocks as modern Precambrian BIF analogues. Spatial coverage of the BIF-type rocks in relation to the economic grade Mn ore that brought prominence to the CVSB implicates tectonic activity and changing redox in the deposition of the BIF-type rocks. Field-wide stratigraphic and biogeochemical reconstruction demonstrates two temporal and spatially isolated iron deposits in the CVSB with distinct sedimentological character. Petrographic screening suggest the previously described photoferrotrophic-like microfossil-rich IF (MFIF), accumulated on basement andesite in a ~ 150 m wide basin, in the SW margin of the basin. A strongly banded non-fossiliferous IF (NFIF) caps the Mn-rich sandstones at the transition to the renowned Mn-rich formation. Geochemical evidence relates the origin of the NFIF to periodic submarine volcanism and water column oxidation of released Fe(II) in conditions apparently predominated by anoxia, similar to the MFIF. This is manifested in the lack of shale-normalized Ce anomalies. Raman spectroscopy pairs hematite-rich grains in the NFIF with relics of a carbonaceous material carrying an average δ13Corg signature of ~ −25 ‰. However, a similar δ13Corg signature in the MFIF is not directly coupled to hematite by mineralogy. The NFIF, which post dates large-scale Mn deposition in the CVSB, is composed primarily of amorphous Si (opal-SiO2 · nH2O) while crystalline quartz (SiO2) predominates the MFIF. An intricate interaction between tectonic processes, changing redox, biological activity and abiotic Si precipitation, formed the unmetamorphosed BIF-type deposits

    Response-order effects in survey methods: A randomized controlled crossover study in the context of sport injury prevention

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    Consistency tendency is characterized by the propensity for participants responding to subsequent items in a survey consistent with their responses to previous items. This method effect might contaminate the results of sport psychology surveys using cross-sectional design. We present a randomized controlled crossover study examining the effect of consistency tendency on the motivational pathway (i.e., autonomy support → autonomous motivation → intention) of self-determination theory in the context of sport injury prevention. Athletes from Sweden (N = 341) responded to the survey printed in either low interitem distance (IID; consistency tendency likely) or high IID (consistency tendency suppressed) on two separate occasions, with a one-week interim period. Participants were randomly allocated into two groups, and they received the survey of different IID at each occasion. Bayesian structural equation modeling showed that low IID condition had stronger parameter estimates than high IID condition, but the differences were not statistically significant

    Estimation of efficiency of the use of financial resources on enterprises

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    Стаття присвячена дослідженню теоретичних та практичних питань аналітичного забезпечення управління використанням фінансових ресурсів підприємств. Запропоновані комплексні показники оцінки даного процесуThe article is devoted to research of theoretical and practical questions of the analytical providing of management the use of financial resources of enterprises. The complex indexes of estimation of this process are offere

    Association Between Physical Performance Tests and External Load During Scrimmages in Highly Trained Youth Ice Hockey Players

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    Author's accepted manuscriptAccepted author manuscript version reprinted, by permission, from International Journal of Sports Physiology and Performance (IJSPP), 2023, 18(1): 47-54, https://doi.org/10.1123/ijspp.2022-0225. © Human Kinetics, Inc.Purpose: To investigate the relationship between physical performance tests and on-ice external load from simulated games (scrimmages) in ice hockey. Methods: A total of 14 players completed a physical performance test battery consisting of 30-m sprint test—run and 30-m sprint test—skate (including 10-m split times and maximum speed), countermovement jump, standing long jump, bench press, pull-ups, and trap bar deadlift and participated in 4 scrimmages. External load variables from scrimmages included total distance; peak speed; slow ( 24.0 km/h) speed skating distance; number of sprints; PlayerLoad™; number of high-intensity events (> 2.5 m/s); accelerations; decelerations; and changes of direction. Bayesian pairwise correlation analyses were performed to assess the relationship between physical performance tests and external load performance variables. Results: The results showed strong evidence (Bayes factor > 10) for associations between pull-ups and high-intensity events (τ = .61) and between maximum speed skate and peak speed (τ = .55). There was moderate evidence (Bayes factor >3 to <10) for 6 associations: both maximum speed skate (τ = .44) and countermovement jump (τ = .44) with sprint speed skating distance, countermovement jump with number of sprints (τ = .46), pull-ups with changes of direction (τ = .50), trap bar with peak speed (τ = .45), and body mass with total distance (τ = .49). Conclusion: This study found physical performance tests to be associated with some of the external load variables from scrimmages. Nevertheless, the majority of correlations did not display meaningful associations, possibly being influenced by the selection of physical performance tests.acceptedVersio

    Investigation of frontal lobe activation with fNIRS and systemic changes during video gaming.

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    Frontal lobe activation caused by tasks such as videogames can be investigated using multichannel near-infrared spectroscopy (fNIRS), sometimes called optical topography. The aims of this study are to investigate the effects of video gaming (fighting and puzzle games) in the brain and the systemic physiology and to determine whether systemic responses during the gaming task are associated with the measurement of localised cerebral haemodynamic changes as measured by fNIRS. We used a continuous-wave 8-channel fNIRS system to measure the changes in concentration of oxy-haemoglobin (HbO2) and deoxy-haemoglobin (HHb) and changes in total haemoglobin (ΔtHb = ΔHbO2 + ΔHHb) over the frontal lobe in 30 healthy volunteers. The Portapres system was used to measure mean blood pressure (MBP) and heart rate (HR), and a laser Doppler was employed to measure the changes in scalp blood flow (or flux). Even though we observed significant changes in systemic variables during gaming, in particular in scalp flow, we also managed to see localised activation patterns over the frontal polar (FP1) region. However, in some channels over the frontal lobe, we also observed significant correlations between the HbO2 and systemic variables

    An interpolation theorem for proper holomorphic embeddings

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    Given a Stein manifold X of dimension n>1, a discrete sequence a_j in X, and a discrete sequence b_j in C^m where m > [3n/2], there exists a proper holomorphic embedding of X into C^m which sends a_j to b_j for every j=1,2,.... This is the interpolation version of the embedding theorem due to Eliashberg, Gromov and Schurmann. The dimension m cannot be lowered in general due to an example of Forster
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