609 research outputs found

    Forecasting longitudinal growth in children's numerical abilities

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    Modern society requires individuals to possess solid numerical skills to succeed in everyday life (Gerardi et al., 2013). Understanding the cognitive and neural markers of early numerical skills could provide much needed information about the development of long-term mathematical capabilities, and inform early intervention for those at risk of mathematical learning disability. In this regard, a longitudinal approach can disentangle whether specific brain networks and cognitive processes are predictive, rather than the consequential effect, of mathematical achievement

    Basic and advanced numerical performances relate to mathematical expertise but are fully mediated by visuospatial skills

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    Recent studies have highlighted the potential role of basic numerical processing in the acquisition of numerical and mathematical competences. However, it is debated whether high-level numerical skills and mathematics depends specifically on basic numerical representations. In this study mathematicians and nonmathematicians performed a basic number line task, which required mapping positive and negative numbers on a physical horizontal line, and has been shown to correlate with more advanced numerical abilities and mathematical achievement. We found that mathematicians were more accurate compared with nonmathematicians when mapping positive, but not negative numbers, which are considered numerical primitives and cultural artifacts, respectively. Moreover, performance on positive number mapping could predict whether one is a mathematician or not, and was mediated by more advanced mathematical skills. This finding might suggest a link between basic and advanced mathematical skills. However, when we included visuospatial skills, as measured by block design subtest, the mediation analysis revealed that the relation between the performance in the number line task and the group membership was explained by non-numerical visuospatial skills. These results demonstrate that relation between basic, even specific, numerical skills and advanced mathematical achievement can be artifactual and explained by visuospatial processing

    High-pressure synthesis and structural behavior of sodium orthonitrate Na3NO4

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    Sodium orthonitrate (Na3NO4) is an unusual phase containing the first example of isolated tetrahedrally bonded NO43- groups. This compound was obtained originally by heating together mixtures of Na2O and NaNO3 for periods extending up to > 14 days in evacuated chambers. Considering the negative volume change between reactants and products, it was inferred that a high-pressure synthesis route might favor the formation of the Na3NO4 compound. We found that the recovered sample is likely to be a high-pressure polymorph, containing NO43- groups as evidenced by Raman spectroscopy. The high-pressure behavior of Na3NO4 was studied using Raman spectroscopy and synchrotron X-ray diffraction in a diamond anvil cell above 60 GPa. We found no evidence for major structural transformations, even following laser heating experiments carried out at high pressure, although broadening of the Raman peaks could indicate the onset of disordering at higher pressure

    A new mechanism for exchange processes observed in the compounds [M(η-C_5H_5)_2(exo-η-RCH = CH_2)H], M = Nb and Ta

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    Dynamic n.m.r. studies of the exchange processes in the complexes [M(η-C_5H_5)(exo-η-RCH=CH_2)H], M = Nb, Ta, lead to the proposal of a new mechanism involving intermediates with agostic bonding

    The expression of a bean PGIP in transgenic wheat confers increased resistance to the fungal pathogen Bipolaris sorokiniana

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    In several plant-pathogen interactions to overcome the barrier represented by cell wall most fungal pathogens produce a variety of hydrolytic enzymes and between them PGs are one of the first to be secreted. We demonstrate that transgenic wheat plants expressing PvPGIP2 showed a significant reduction of symptoms following the infection of Bipolaris sorokiniana suggesting that pectin hydrolysis is an important step for fungal penetration of wheat plants.In molti sistemi pianta patogeno i patogeni al fine di superare l’ostacolo rappresentato dalla parete cellulare producono degli enzimi idrolitici tra cui le Poligalatturonasi ( PG) sono tra i primi ad essere secreti. In questo lavoro dimostriamo che piante transgeniche di frumento sovraesprimenti la PvPGIP2 mostrano una significativa riduzione nella sintomatologia riscontrata in seguito ad infezione con Bipolaris sorokiniana suggerendo che l’idrolisi della pectina rappresenta uno step importante per la penetrazione e la colonizzazione dei tessuti di frumento.L'articolo é disponibile sul sito dell'editore: http://www.apsjournals.apsnet.or

    Exercise Intervention to Improve Functional Capacity in Older Adults After Acute Coronary Syndrome

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    More than one-half of patients admitted for acute coronary syndrome (ACS) are age 70years.MobilitylimitationsandsedentarybehaviorarecommoninolderACSpatientsandcontributetohighriskofrecurrenceandmortality(1).AlthougholderACSpatientsmaybenefitthemostfromparticipationinexercise−basedcardiacrehabilitation/secondarypreventionprograms(CR/SP),theyarelesslikelytoparticipateinsuchprograms(2).Whetheranearly,individualized,andlow−costphysicalactivity(PA)interventionincludingafewsupervisedsessionsandahome−basedprogrammightbefeasibleandeffectiveforimprovingfunctionalcapacityinthishigh−riskandundertreatedpopulationisunknown.TheHULK(PhysicalActivityInterventionforPatientsWithReducedPhysicalPerformanceAfterAcuteCoronarySyndrome;NCT03021044)trialisamulticenter,randomizedclinicaltrial.Adetailedstudyoutlineandstatisticalplanhavebeenpreviouslypublished(3).Inclusioncriteriawereage70 years. Mobility limitations and sedentary behavior are common in older ACS patients and contribute to high risk of recurrence and mortality (1). Although older ACS patients may benefit the most from participation in exercise-based cardiac rehabilitation/secondary prevention programs (CR/SP), they are less likely to participate in such programs (2). Whether an early, individualized, and low-cost physical activity (PA) intervention including a few supervised sessions and a home-based program might be feasible and effective for improving functional capacity in this high-risk and undertreated population is unknown. The HULK (Physical Activity Intervention for Patients With Reduced Physical Performance After Acute Coronary Syndrome; NCT03021044) trial is a multicenter, randomized clinical trial. A detailed study outline and statistical plan have been previously published (3). Inclusion criteria were age 70 years, hospitalization for ACS, and Short Physical Performance Battery (SPPB) score between 4 and 9 at the inclusion visit (30 5 days after hospital discharge). The SPPB is a scale that combines gait speed, chair stand, and balance tests. It ranges from 0 (worst) to 12 (best) and has predictive validity for mortality (4). Participants were randomized to usual care and health education (control group) or usual care and PA intervention (intervention group). The control group received a 20-min session and a detailed brochure stressing the importance of PA in cardiovascular health. The PA intervention consisted of four supervised sessions (1, 2, 3, and 4 months after hospital discharge), combined with an individualized home-based PA program. Centerbased sessions included a moderate standardized treadmill-walk, strength, and balance exercises (3). After the practice sessions, patients received a tailored PA home program (3). Weekly energy expenditure from PA was determined by a selfreported 7-day physical activity recall (kcal/week), and objectively measured by wearing an accelerometer (min/week). The primary endpoint was the 6- month SPPB. Secondary endpoints were 1-year SPPB and time engaged in PA. From January 2017 to April 2018, 235 patients were randomized (n ¼ 117, control group; n ¼ 118, intervention group). The median age was 76 (interquartile range [IQR]: 73 to 81) years, and 23% were female. Before the hospitalization, light and moderateintensive PA was performed by 66% and 14% of patients, respectively. Baseline characteristics, as well as baseline SPPB value (Figure 1), did not differ between groups. The adherence rates of the PA intervention group to the 1-, 2-, 3-, and 4-month scheduled supervised sessions were 100%, 89%, 85%, and 72%, respectively. The time engaged in PA progressively and significantly increased in the intervention group (Figure 1). At 6 months, the SPPB score was significantly higher in the intervention group (median: 9 [IQR: 8 to 11] vs. 7 [IQR: 5 to 8]; p < 0.001) (Figure 1). This improvement was supported by a significant increase in SPPB components of walking and chair rise (balance remained unchanged). The number of patients showing an increase of at least 1 point in SPPB score was 86 (74%) in the intervention group versus 46 (40%) in the control group (p < 0.001). The SPPB increase was maintained at the 1-year visit (Figure 1) and independent of sex and educational status. Typical CR/SP includes 3 weekly supervised exercise and educational sessions for 12 weeks. Despite the health benefits associated with these interventions, few eligible patients are referred or complete such programs (1). Our novel PA intervention was designed to address this issue. The attendance rate was high (72% [95% confidence interval: 64% to 80%]). The average weekly energy expenditure from PA in the intervention group increased 3.4 times, and SPPB score showed a mean increment of 2.0 points. This finding is notable given that an SPPB improvement of 1.0 point is generally considered a substantial clinically meaningful change (2). In addition, despite the absence of supervised sessions after the sixth month, the achievements were maintained until 1-year visit. If confirmed in future studies, our PA intervention model might help to mitigate the challenges related to limited health care resources and might increase the number of older adults receiving CR/SP
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