32 research outputs found
Rapid determination of esterified glycerol and glycerides in triglycerides fats and oils by means of periodate method after transesterfication
The paper describes an accurate method to determine esterified glycerol in the glycerides edible fats and oils and in general in all triglycerides fats and oils
Photometric determination of the mass accretion rates of pre-main sequence stars. II. NGC346 in the Small Magellanic Cloud
[Abridged] We have studied the properties of the stellar populations in the
field of the NGC346 cluster in the Small Magellanic Cloud, using a novel
self-consistent method that allows us to reliably identify pre-main sequence
(PMS) objects actively undergoing mass accretion, regardless of their age. The
method does not require spectroscopy and combines broad-band V and I photometry
with narrow-band Halpha imaging to identify all stars with excess Halpha
emission and derive the accretion luminosity Lacc and mass accretion rate Macc
for all of them. The application of this method to existing HST/ACS photometry
of the NGC346 field has allowed us to identify and study 680 bona-fide PMS
stars with masses from ~0.4 to ~4 Msolar and ages in the range from ~1 to ~30
Myr. This is the first study to reveal that, besides a young population of PMS
stars (~ 1 Myr old), in this field there is also an older population of PMS
objects with a median age of ~20 Myr. We provide for all of them accurate
physical parameters. We study the evolution of the mass accretion rate as a
function of stellar parameters and find that logMacc ~ -0.6 Log t + Log m + c,
where t is the age of the star, m its mass and c a quantity that is higher at
lower metallicity. The high mass accretion rates that we find suggest that a
considerable fraction of the stellar mass is accreted during the PMS phase and
that PMS evolutionary models that do not account for this effect will
systematically underestimate the true age when compared with the observations.Comment: Accepted for publication in the ApJ. 14 pages, 11 figures. Corrected
typos and reference
The James Webb Space Telescope Mission
Twenty-six years ago a small committee report, building on earlier studies,
expounded a compelling and poetic vision for the future of astronomy, calling
for an infrared-optimized space telescope with an aperture of at least .
With the support of their governments in the US, Europe, and Canada, 20,000
people realized that vision as the James Webb Space Telescope. A
generation of astronomers will celebrate their accomplishments for the life of
the mission, potentially as long as 20 years, and beyond. This report and the
scientific discoveries that follow are extended thank-you notes to the 20,000
team members. The telescope is working perfectly, with much better image
quality than expected. In this and accompanying papers, we give a brief
history, describe the observatory, outline its objectives and current observing
program, and discuss the inventions and people who made it possible. We cite
detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space
Telescope Overview, 29 pages, 4 figure
Impiego in agricoltura dei residui delle foglie di tabacco provenienti dalle lavorazioni delle manifatture tabacchi
Determination of nicotine content in the soil mixed with tobacco powder as fertilizer
In questo lavoro è stata messa a punto una procedura di smaltimento della polvere di tabacco nel terreno come ammendante. La concentrazione della nicotina è stata monitorata nel tempo per studiarne il tempo di decacimento
Ottimizzazione del processo di fumigazione con fosfina.
La disinfestazione dei prodotti agricoli essiccati (frutta secca, cereali, thé, caffè, camomilla, tabacco ecc.), mediante fumigazione con fosfina, rappresenta una pratica ampiamente adoperata. Tale processo è realizzato mediante l’utilizzo di formulati a base di Fosfuro di Magnesio o Fosfuro di Alluminio, in forma di pelletts. Questi formulati, nelle normali condizioni di uso, reagiscono con l’umidità dell’aria, generando fosfina allo stato gassoso, dotata di una elevata azione disinfestante. I pelletts, durante l’esposizione all'aria, sfioriscono generando un sottile residuo polverulento che ostacolando la diffusione dell'umidità atmosferica, rallenta la reazione per la produzione di fosfina. Per questo motivo, dopo il normale periodo di fumigazione di cinque giorni, il residuo polverulento contiene ancora 1-2 % di principio attivo; pertanto il residuo, secondo la normativa vigente, è da considerarsi, tossico e nocivo. Da quanto esposto risulta evidente che l' esaurimento totale del principio attivo in un tempo ragionevole si può ottenere rimescolando continuamente il residuo polverulento. In aggiunta la velocità della produzione di fosfina dipende dalla quantità di acqua presente e dalla temperatura. In sintesi i parametri che consentono di esaurire completamente il principio attivo e di ridurre i tempi di reazione da cinque giorni a due giorni sono : rimescolamento, aggiunta di acqua al principio attivo e suo riscaldamento durante la fase di reazione. E' stato progettato e realizzato un dispositivo che prevede l' impiego dei parametri sopra riportati. Il dispositivo, di facile uso, consente di esaurire in maniera completa il principio attivo e di ridurre il tempo di produzione di fosfina da 5 giorni a 2 giorni. In aggiunta, il dispositivo risulta particolarmente conveniente nelle fumigazioni in periodi freddi
Reviewing the relationship between physiology of breathing and physical activity in anxiety disorders
The possible influence of the quality of breathing on physical activity remains the subject of numerous scientific studies in different fields, including not only the most basic physiological and biological concepts but also the fields of psychiatry, psychology, and neuroscience. The literature about the relationship between breathing and psychophysiological factors is continuously growing, and several studies have investigated the influence of breathing techniques on human beings. This review aims to give a literature overview of the respiratory function impact on psychopathology, taking into account anxiety disorders, physical activity, and the relationship between them. Literature investigating different topics involving the influence of breathing on anxiety disorders, the influence of breathing on physical activity and related anxiety disorders showed an association between them even if this relationship is not well clarified. Regular physical activity could become even a primary or preferential treatment. Relaxation techniques, as well as motor visualization, mindfulness, and even oral appliances, could help people improve their general condition with the improvement of the control of their psychophysical performance. Further literature with different physical activities and experiences regarding psychodynamic treatments could assume a new scenario.Scopu
Improved Fumigation Process for Stored Foodstuffs by Using Phosphine in Sealed Chambers
In this paper we present an innovative device designed and constructed to improve the fumigation process for stored foodstuffs with the use of phosphine gas in sealed chambers. The device allowed a considerable reduction in phosphine production time (from about 5 to 7 days for traditional systems to 2 days for the equipment considered), maintaining the system below the inflammability threshold, and at the same time achieving the total exhaustion of aluminum (or magnesium) phosphide so as to avoid toxic residues at the end of the process. With the standard device currently available on the market, after the normal 5–7 day fumigating period, the powder residue contains as much as 1–2% (w/w) of phosphide. Thus the residues, according to current legislation, have to be considered toxic and harmful. To overcome this disadvantage, appropriate modifications were made to the cylindrical tray used for the fumigation process: a nebulizer was installed, which has the function of increasing the moisture of the air spreading around the phosphide pellets and allowing a more rapid reaction with phosphide. Moreover, the cylindrical tray was also heated by means of an electrical resistance, and temperature was checked by a thermostat, so as to always obtain the same efficiency, independently of outside temperature, for both hot and cold periods, since reaction speed depends on the system temperature considered. In addition, a control device for air saturation allows condensation processes to be avoided. Using the modified cylindrical tray we performed tests to determine the best values of humidity and temperature for the process concerned, avoiding phosphine concentrations that might result in a fire hazard, and the remixing of phosphide pellets inside the cylindrical tray. Our experimental data allowed us to obtain a mathematical model used to gain an insight into the process in question
Reviewing the relationship between physiology of breathing and physical activity in anxiety disorders
The possible influence of the quality of breathing on physical activity remains the subject of numerous scientific studies in different fields, including not only the most basic physiological and biological concepts but also the fields of psychiatry, psychology, and neuroscience. The literature about the relationship between breathing and psychophysiological factors is continuously growing, and several studies have investigated the influence of breathing techniques on human beings. This review aims to give a literature overview of the respiratory function impact on psychopathology, taking into account anxiety disorders, physical activity, and the relationship between them. Literature investigating different topics involving the influence of breathing on anxiety disorders, the influence of breathing on physical activity and related anxiety disorders showed an association between them even if this relationship is not well clarified. Regular physical activity could become even a primary or preferential treatment. Relaxation techniques, as well as motor visualization, mindfulness, and even oral appliances, could help people improve their general condition with the improvement of the control of their psychophysical performance. Further literature with different physical activities and experiences regarding psychodynamic treatments could assume a new scenario