Analisi scientifiche sulle tempere murali di Villa Pace

International audienceThe morphology, mineralogy, and solid-liquid phase separation of the Cu and Zn precipitates formed with sulfide produced in a sulfate-reducing bioreactor were studied at pH 3, 5, and 7. The precipitates formed at pH 7 display faster settling rates, better dewaterability, and higher concentrations of settleable solids as compared to the precipitates formed at pH 3 and 5. These differences were linked to the agglomeration of the sulfidic precipitates and coprecipitation of the phosphate added to the bioreactor influent. The Cu and Zn quenched the intensity of the dissolved organic matter peaks identified by fluorescence-excitation emission matrix spectroscopy, suggesting a binding mechanism that decreases supersaturation, especially at pH 5. X-ray absorption fine structure spectroscopy analyses confirmed the precipitation of Zn-S as sphalerite and Cu-S as covellite in all samples, but also revealed the presence of Zn sorbed on hydroxyapatite. These analyses further showed that CuS structures remained amorphous regardless of the pH, whereas the ZnS structure was more organized at pH 5 as compared to the ZnS formed at pH 3 and 7, in agreement with the cubic sphalerite-type structures observed through scanning electron microscopy at pH 5

Wide-bandgap InAs/InGaP quantum-dot intermediate band solar cells

Current prototypes of quantum-dot intermediate band solar cells suffer from voltage reduction due to the existence of carrier thermal escape. An enlarged sub-bandgap EL would not only minimize this problem, but would also lead to a bandgap distribution that exploits more efficiently the solar spectrum. In this work we demonstrate InAs/InGaP QD-IBSC prototypes with the following bandgap distribution: EG = 1.88 eV, EH = 1.26 eV and EL > 0.4 eV. We have measured, for the first time in this material, both the interband and intraband transitions by means of photocurrent experiments. The activation energy of the carrier thermal escape in our devices has also been measured. It is found that its value, compared to InAs/GaAs-based prototypes, does not follow the increase in EL. The benefits of using thin AlGaAs barriers before and after the quantum-dot layers are analyzed

Planck pre-launch status: Low Frequency Instrument calibration and expected scientific performance

We give the calibration and scientific performance parameters of the Planck Low Frequency Instrument (LFI) measured during the ground cryogenic test campaign. These parameters characterise the instrument response and constitute our best pre-launch knowledge of the LFI scientific performance. The LFI shows excellent $1/f$ stability and rejection of instrumental systematic effects; measured noise performance shows that LFI is the most sensitive instrument of its kind. The set of measured calibration parameters will be updated during flight operations through the end of the mission.Comment: Accepted for publications in Astronomy and Astrophysics. Astronomy & Astrophysics, 2010 (acceptance date: 12 Jan 2010

La actividad física organizada en las personas mayores, una herramienta para mejorar la condición física en la senectud

Fundamentos. Un nivel adecuado de condición física (CF) es fundamental para el logro de un envejecimiento saludable. El objetivo de este estudio consistió en evaluar el impacto de la actividad física (AF) organizada y el número de horas de práctica sobre el nivel de CF de las personas mayores. Método. En el estudio participaron 3104 personas mayores de 65 años de España, pertenecientes al Proyecto Multicéntrico EXERNET (722 hombres y 2382 mujeres; edad media: 72, 1±5, 3 años). La CF se evaluó mediante 8 test específicos para esta población. La participación en AF organizada se registró mediante un cuestionario. Las diferencias en la CF en función de la práctica y número de horas de AF se midieron con ANCOVA ajustando por edad, horas de caminar y de estar sentado. Resultados. Aquellos que no participaban en este tipo de actividad incrementaban su riesgo de tener un nivel bajo de CF en la mayoría de las variables evaluadas, observándose algunas diferencias entre sexos (OR: desde 1, 6 hasta 2, 6 en hombres y desde 1, 4 hasta 2, 2 en mujeres). En los hombres no se observó ninguna diferencia significativa entre practicar menos de 2, 2-4 o más de 4 horas (todos P>0, 05), a excepción de la fuerza del brazo izquierdo; sin embargo, las mujeres que realizaban más de 2 horas de AF organizada a la semana tenían mayor equilibrio, fuerza de piernas y de brazos, flexibilidad de piernas, velocidad al caminar y resistencia aeróbica que aquellas que asistían a este tipo de sesiones menos de 2 horas a la semana (P<0, 05). Conclusiones. La práctica de AF organizada produce un efecto beneficioso sobre la CF de las personas mayores independientemente de la edad, las horas que estén sentados o el tiempo que dediquen a caminar. Background. An adequate level of fitness is critical to achieving healthy ageing. The aim of this study was to evaluate the impact of organized physical activity (PA) and the number of hours of practice on the fitness levels of the elderly. Method. A total of 3104 people over 65 years old from Spain, belonging to the EXERNET Multicenter Project (722 men and 2382 women, mean age: 72.1 +/- 5.3 years) participated in the study. Fitness was evaluated by 8 specific tests for this population. Participation in organized PA was recorded through a questionnaire. Differences in fitness values depending on the participation in PA and the number of hours were measured with ANCOVA adjusting for age, hours of walking and sitting time. Results. Those who did not participate in this type of activity increased their risk of having a low level of fitness in most variables evaluated, with some differences between sexes (OR: from 1.6 to 2.6 in men and from 1.4 to 2.2 in women). In men, no significant differences were observed between practicing less than 2, 2-4 or more than 4 hours (P>0, 05), with an exception in the strength of the left arm. However, women who performed more than 2 hours a week in organized PA had better balance, strength of lower and upper extremities, flexibility of lower extremities, walking speed and aerobic capacity than those who performed less than 2 hours of PA a week (P<0, 05). Conclusions. The practice of organized PA produces a beneficial effect on the fitness of the elderly regardless of age, hours of walking and time sitting per day

Search for tau -> e gamma decay at Belle

We have searched for the lepton-flavor-violating decay tau -> e gamma using a data sample of 86.7/fb collected with the Belle detector at the KEKB asymmetric e^+ e^- collider. No evidence for a signal is obtained, and we set an upper limit for the branching fraction Br(tau -> e gamma) < 3.9 x 10^-7 at the 90% C.L.Comment: 11 pages, 10 figures, ReVTeX4, eps

Evolución de los niveles de condición física en población octogenaria y su relación con un estilo de vida sedentario

Objetivos: Determinar los cambios que se producen enla condición física a lo largo de dos años de seguimiento enoctogenarios y comprobar si un estilo de vida sedentariomodifica estas variaciones. Metodología: La condición física de 182 sujetos (48hombres, 134 mujeres) con una media de edad de 82,3 ±2,3 años se evaluó mediante 8 test (adaptados de las bate-rías “Senior Fitness Test” y “Eurofit”). Se realizó un aná-lisis de medidas repetidas entre los dos periodos de eva-luación y para ver las diferencias de condición física entrelos sujetos considerados sedentarios (permanecían senta-dos = 4 horas/día) y no sedentarios (permanecían senta-dos < 4 horas/día) Resultados: Entre las dos evaluaciones encontramos undescenso significativo en los test de agilidad (p 4 horas/día sufrieron un descen-so de la agilidad (p < 0,05). Se produjo una pérdida de ve-locidad y resistencia tanto en sedentarios como en no se-dentarios (p < 0,05). Conclusión: En dos años de seguimiento, se producencambios negativos en el nivel de condición física en perso-nas octogenarias. Periodos prolongados de sedestación setraducen en una pérdida de agilidad. La velocidad de lamarcha y resistencia parecen ser los componentes de lacondición física más afectados por el proceso de envejeci-miento en este grupo poblacional y su pérdida no vienedeterminada por las horas diarias de sedestación. Objective: The aim of this study was to determine the changes in physical fitness over two years of following up in octogenarian people and to check whether a sedentary lifestyle modify these variations. Methods: Physical fitness of 182 subject (48 men, 134 women)with a mean age of 82,3 ± 2,3 years were evaluated using 8 different tests. A repeated measures analysis was carried out to see the differences between the two evaluation periods and to see the physical fitness differences between sedentary people (sit = 4 hours/day)and non sedentary people (sit 4 hours/day there was a decrease in the walking speed test between the two evaluations (p < 0.05). Moreover, there was a decrease of walking speed and endurance between the two evaluation periods in both sedentary and nonsedentary people (p < 0.05). Conclusion: In two years of following up, there are adverse changes in the level of physical fitness in octogenarians. Long periods of sitting time may translate into a loss of agility. Walking speed and endurance seem to be the components of physical fitness more affected by the ageing process in this population; and this loss is not determined by the hours of sitting per day

Geographical, seasonal, and depth variation in sinking particle speeds in the North Atlantic

Particle sinking velocity is considered to be a controlling factor for carbon transport to the deep sea and thus carbon sequestration in the oceans. The velocities of the material exported to depth are considered to be high in high-latitude productive systems and low in oligotrophic distributions. We use a recently developed method based on the measurement of the radioactive pair 210Po-210Pb to calculate particle sinking velocities in the temperate and oligotrophic North Atlantic during different bloom stages. Our estimates of average sinking velocities (ASVs) show that slowly sinking particles (&lt;100?m?d?1) contribute significantly to carbon flux at all the locations except in the temperate regions during the bloom. ASVs appear to vary strongly with season, which we propose is caused by changes in the epipelagic community structure. Our results are the first field data to confirm the long-standing theory that particle sinking velocities increase with depth, with increases of up to 90% between 50 and 150?m depth