Asociación mineralógica de la zona de alteración argilica avanzada en un yacimiento de Caolín de la Patagonia Argentina

En la provincia de Río Negro (norte de la Patagonia Argentina) los yacimientos de caolín se encuentran emplazados en rocas volcanoclásticas de edad Triásico Superior – Jurásico Medio. Esta secuencia comienza con andesitas y tobas andesíticas y culmina con riolitas y sus tobas cosanguíneas. La roca de caja del yacimiento estudiado, mina Loma Blanca, es andesítica. Está ubicado a 70 km al NO de la localidad de Los Menucos. En trabajos previos se estudió la geoquímica y zonación de alteración desde la zona propilítica hasta la argílica avanzada, con el propósito de establecer la génesis. Para ello se realizaron análisis químicos de elementos mayoritarios, minoritarios, traza e isótopos de O y D y se concluyó que el yacimiento se formó por la circulación de fluidos hidrotermales de elevada temperatura y presión. Este trabajo consiste en el estudio de los minerales de alteración desarrollados en la zona de alteración argílica avanzada con el propósito de establecer su secuencia de formación a fin de determinar la posible existencia de diferentes pulsos de mineralización relacionados con los sulfuros de Cu, Fe, Pb y Zn mencionados en la bibliografía. Se identificó dickita, caolinita, natroalunita, pirofilita, diasporo y cuarzo secundario. Se utilizó microscopía de polarización sobre secciones delgadas para evaluar las relaciones genéticas, microscopía electrónica de barrido, EDS y difractometría de rayos X para identificar los minerales presentes y el contenido de Na y K de la alunita. Se determinó la siguiente secuencia paragenética: 1. diasporo, 2. pirofilita, 3. natroalunita, 4. dickita, 5. caolinita

Highly diastereoselective entry into chiral spirooxindole-based 4-methyleneazetidines via formal [2+2] annulation reaction

We describe here a diastereoselective, DABCO-catalyzed reaction of allenoates with chiral N-tert-butanesulfinyl ketimines derived from isatin

Relation among perceived weight change, sedentary activities and sleep quality during covid-19 lockdown: A study in an academic community in Northern Italy

In Italy, COVID-19 lockdown was imposed from 8 March until 3 May 2020 with negative consequences on the lifestyles and health of people. Within this context, the paper aims: (i) to analyse the impact of COVID-19 lockdown on perceived weight changes; (ii) to evaluate factors associated with the perception of weight changes (Body Mass Index (BMI), sleep quality, time spent in sedentary activities), in an Italian academic community of students and workers. A total of 3666 participants took part in this cross-sectional study (2838 students and 828 workers, of whom 73.0% were female). T-test, Chi-square test and the two-way ANOVA were used. Results showed that 43.3% of participants perceived a weight gain. Workers experienced a more substantial increase in body weight (0.7 kg) compared to students (0.3 kg; p = 0.013). A significant difference between preobese/obese workers (0.9 kg) and students (−0.3 kg; p < 0.001) was found. Overall, 57.0% of the sample was characterized by high levels of sedentary activities. Sedentary people noticed a higher weight gain (0.4 kg) compared to less sedentary people (0.3 kg; p = 0.048). More than 45% of participants reported a worsening of sleep quality and showed a perceived increase in body weight (0.5 kg) in comparison to those who improved their sleep quality (no weight change; p = 0.001). Designing tailored interventions to promote health-related behaviours during lockdown periods is essential

Rate of force development as an indicator of neuromuscular fatigue: a scoping review

Because rate of force development (RFD) is an emerging outcome measure for the assessment of neuromuscular function in unfatigued conditions, and it represents a valid alternative/complement to the classical evaluation of pure maximal strength, this scoping review aimed to map the available evidence regarding RFD as an indicator of neuromuscular fatigue. Thus, following a general overview of the main studies published on this topic, we arbitrarily compared the amount of neuromuscular fatigue between the "gold standard" measure (maximal voluntary force, MVF) and peak, early (≤100 ms) and late (>100 ms) RFD. Seventy full-text articles were included in the review. The most-common fatiguing exercises were resistance exercises (37% of the studies), endurance exercises/locomotor activities (23%), isokinetic contractions (17%), and simulated/real sport situations (13%). The most widely tested tasks were knee extension (60%) and plantar flexion (10%). The reason (i.e., rationale) for evaluating RFD was lacking in 36% of the studies. On average, the amount of fatigue for MVF (-19%) was comparable to late RFD (-19%) but lower compared to both peak RFD (-25%) and early RFD (-23%). Even if the rationale for evaluating RFD in the fatigued state was often lacking and the specificity between test task and fatiguing exercise characteristics was not always respected in the included studies, RFD seems to be a valid indicator of neuromuscular fatigue. Based on our arbitrary analyses, peak RFD and early phase RFD appear even to be more sensitive to quantify neuromuscular fatigue than MVF and late phase RFD

he Cut-Off Value for Classifying Active Italian Children Using the Corresponding National Version of the Physical Activity Questionnaire

The present study aimed to determine a cut-off value following the filling in of a questionnaire (PAQ-C-It) to identify active Italian children. One-hundred-twenty-nine primary school children (5 Piedmont schools; 47.3% female; mean age = 10 ± 1 years) wore an accelerometer (Actigraph wGT3X-BT) to objectively quantify individual moderate-to-vigorous physical activity during one week. Afterwards, the PAQ-C-It was filled in by participants. A ROC curve procedure was applied to obtain an active/non-active cut-off point. Spearman's correlation coefficient was also applied to establish the relationship between the two parameters. According to the ROC analysis, the PAQ-C-It cut-off point value is identifiable at >2.75 to indicate active children (area under the curve = 0.62; standard error = 0.05; p = 0.025; coefficient intervals = 0.518-0.716; sensitivity = 0.592, specificity = 0.382), determining that 65 participants (55%) were non-active (mean PAQ-C-It value = 2.3 ± 0.4; active mean PAQ-C-It value = 3.3 ± 0.4). Spearman's correlation coefficient results were significant but with a small effect size (rho = 0.214; p = 0.008). In conclusion, the present results suggest that the PAQ-C-It can be cautiously used as tool to practically classify active Italian children because of a non-solid relationship between respective accelerometer data and MVPA daily data