2,344 research outputs found

    Control biologico del gusano cachon (Erinnyis ello)

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    A program of biological control of the cassava hornworm appears feasible. The following biological control agents have been found to reduce hornworm populations effectively: Trichogramma spp. (egg parasites), Apanteles spp. (larval parasites), Polistes spp. (larval predators) and Bacillus thuringiensis (pathogenic to larvae). Further studies are required to develop the program better and test it at a commercial level. (AS-CIAT

    Precise measurement of the 222Rn half-life: a probe to monitor the stability of radioactivity

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    We give the results of a study on the 222Rn decay we performed in the Gran Sasso Laboratory (LNGS) by detecting the gamma rays from the radon progeny. The motivation was to monitor the stability of radioactivity measuring several times per year the half-life of a short lifetime (days) source instead of measuring over a long period the activity of a long lifetime (tens or hundreds of years) source. In particular, we give a possible reason of the large periodical fluctuations in the count rate of the gamma rays due to radon inside a closed canister which has been described in literature and which has been attributed to a possible influence of a component in the solar irradiation affecting the nuclear decay rates. We then provide the result of four half-life measurements we performed underground at LNGS in the period from May 2014 to January 2015 with radon diffused into olive oil. Briefly, we did not measure any change of the 222Rn half-life with a 8*10^-5 precision. Finally, we provide the most precise value for the 222Rn half-life: 3.82146(16){stat}(4){syst} days.Comment: Accepted for publication in Physics Letters B, 6 pages, 6 figure

    Search for correlations between solar flares and decay rate of radioactive nuclei

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    The deacay rate of three different radioactive sources 40K, 137Cs and natTh has been measured with NaI and Ge detectors. Data have been analyzed to search for possible variations in coincidence with the two strongest solar flares of the years 2011 and 2012. No significant deviations from standard expectation have been observed, with a few 10-4 sensitivity. As a consequence, we could not find any effect like that recently reported by Jenkins and Fischbach: a few per mil decrease in the decay rate of 54Mn during solar flares in December 2006.Comment: 5 pages, 3 figure

    Search for time modulations in the decay rate of 40K and 232Th

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    Time modulations at per mil level have been reported to take place in the decay constant of about 15 nuclei with period of one year (most cases) but also of about one month or one day. In this paper we give the results of the activity measurement of a 40K source and a 232Th one. The two experiments have been done at the Gran Sasso Laboratory during a period of about 500 days, above ground (40K) and underground (232Th) with a target sensitivity of a few parts over 10^5. We also give the results of the activity measurement at the time of the X-class solar flares which took place in May 2013. Briefly, our measurements do not show any evidence of unexpected time dependence in the decay rate of 40K and 232Th.Comment: version accepted for publication (Astroparticle Physics

    Producción de material de siembra de yuca

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    Large-scale numerical modeling of hydro-acoustic waves generated by tsunamigenic earthquakes

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    Abstract. Tsunamigenic fast movements of the seabed generate pressure waves in weakly compressible seawater, namely hydro-acoustic waves, which travel at the sound celerity in water (about 1500 m s−1). These waves travel much faster than the counterpart long free-surface gravity waves and contain significant information on the source. Measurement of hydro-acoustic waves can therefore anticipate the tsunami arrival and significantly improve the capability of tsunami early warning systems. In this paper a novel numerical model for reproduction of hydro-acoustic waves is applied to analyze the generation and propagation in real bathymetry of these pressure perturbations for two historical catastrophic earthquake scenarios in Mediterranean Sea. The model is based on the solution of a depth-integrated equation, and therefore results are computationally efficient in reconstructing the hydro-acoustic waves propagation scenarios

    Rapid review on covid-19, work-related aspects, and age differences

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    The COVID-19 pandemic significantly impacted the labor market and multiple aspects of work and workers’ life. The present rapid review analyzes this impact considering the effects that COVID-19 pandemic had on employment and work-related aspects across different age groups. A comprehensive literature search was performed on scientific contributions published between 2019 and March 2021, resulting in 36 papers pertinent to the scope of this review. Findings were grouped according to different topics, all linked to age: occupational risk, implications on the labor market (i.e., job loss and reemployment, job insecurity, turnover intentions and retirement, and healthcare workers’ return-to-work phase), remote work, and key individual and organizational resources and strategies. Overall, the review revealed variability across age groups in the impact this pandemic had on employment and several work-related aspects (i.e., occupational risk, remote work). Findings supported an age-differential effect of normative history-graded events such as the current pandemic, highlighting different responses and consequences depending on workers’ age

    Nucleon decay and atmospheric neutrinos in the Mont Blanc experiment

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    In the NUSEX experiment, during 2.8 years of operation, 31 fully contained events have been collected; 3 among them are nucleon decay candidates, while the others have been attributed to upsilon interactions. Limits on nucleon lifetime and determinations of upsilon interaction rates are presented

    Primary cosmic ray spectrum in the 10 to the 12th power - 10 to the 16th power eV energy range from the NUSEX experiment

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    A primary cosmic ray spectrum was derived which fits both experimental multiple muon rates and the all-nucleon flux derived from the single muon intensities underground. In the frame of the interaction model developed by Gaisser, Elbert and Stanev, it is possible to reproduce NUSEX muon data with a primary composition in which the iron spectrum is only slightly flatter than the proton one. This result rules out the popular idea that the primary composition varies drastically with increasing energy, leading to the dominance of heavier nuclei at energies 10 to the 15th power to 10 to the 16th power eV
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