379 research outputs found
Hybrid star structure with the Field Correlator Method
We explore the relevance of the color-flavor locking phase in the equation of
state (EoS) built with the Field Correlator Method (FCM) for the description of
the quark matter core of hybrid stars. For the hadronic phase, we use the
microscopic Brueckner-Hartree-Fock (BHF) many-body theory, and its relativistic
counterpart, i.e. the Dirac-Brueckner (DBHF). We find that the main features of
the phase transition are directly related to the values of the quark-antiquark
potential , the gluon condensate and the color-flavor
superconducting gap . We confirm that the mapping between the FCM and
the CSS (constant speed of sound) parameterization holds true even in the case
of paired quark matter. The inclusion of hyperons in the hadronic phase and its
effect on the mass-radius relation of hybrid stars is also investigated.Comment: 15 pages, 8 figures ; revised version to be published in the EPJA
Topical Issue on "Exotic Matter in Neutron Stars
THE STATISTICAL ASTEROID MODEL. I. THE MAIN-BELT POPULATION FOR DIAMETERS GREATER THAN 1 KILOMETER
We describe the creation of a model of the main asteroid belt whose purpose is to describe the main-belt asteroid size frequency distribution and simulate the number of main-belt asteroids and their fluxes at visual through mid-infrared (~0.3–70 μm) wavelengths in any area of sky for an arbitrary date. This model is based on a population of ~1.9 × 106 asteroids obtained from the complete known asteroid sample, plus extrapolation of the size-frequency distributions of 15 asteroid dynamical families and three background populations, to a diameter limit of 1 km. The model is compared with data and other models, example applications are given, planned refinements and extensions to the model are presented, and some implications of the resulting size frequency distribution are discussed
Not all remote workers are similar: Technology acceptance, remote work beliefs, and wellbeing of remote workers during the second wave of the covid-19 pandemic
Although a large part of the world’s workforce engaged in mandatory Work from Home during the COVID-19 pandemic, the experience was not the same for everyone. This study explores whether different groups of employees, based on their work and organizational characteristics (i.e., organizational size, number of days per week working from home, working in team) and personal characteristics (i.e., remote work experience, having children at home), express different beliefs about working remotely, acceptance of the technology necessary to Work from Home, and well-being. A study was conducted with 163 Italian workers who answered an online questionnaire from November 2020 to January 2021. A cluster analysis revealed that work, organizational, and personal variables distinguish five different types of workers. ANOVA statistics showed that remote workers from big companies who worked remotely several days a week, had experience (because they worked remotely before the national lockdowns), and worked in a team, had more positive beliefs about working remotely, higher technology acceptance, and better coping strategies, compared to the other groups of workers. Practical implications to support institutional and organizational decision-makers and HR managers to promote remote work and employee well-being are presented
Extreme Kuiper Belt Object 2001 QG298 and the Fraction of Contact Binaries
Extensive time-resolved observations of Kuiper Belt object 2001 QG298 show a
lightcurve with a peak-to-peak variation of 1.14 +-0.04 magnitudes and
single-peaked period of 6.8872 +- 0.0002 hr. The mean absolute magnitude is
6.85 magnitudes which corresponds to a mean effective radius of 122 (77) km if
an albedo of 0.04 (0.10) is assumed. This is the first known Kuiper Belt object
and only the third minor planet with a radius > 25 km to display a lightcurve
with a range in excess of 1 magnitude. We find the colors to be typical for a
Kuiper Belt object (B-V = 1.00 +- 0.04, V-R = 0.60 +- 0.02) with no variation
in color between minimum and maximum light. The large light variation,
relatively long double-peaked period and absence of rotational color change
argue against explanations due to albedo markings or elongation due to high
angular momentum. Instead, we suggest that 2001 QG298 may be a very close or
contact binary similar in structure to what has been independently proposed for
the Trojan asteroid 624 Hektor. If so, its rotational period would be twice the
lightcurve period or 13.7744 +- 0.0004 hr. By correcting for the effects of
projection, we estimate that the fraction of similar objects in the Kuiper Belt
is at least 10% to 20% with the true fraction probably much higher. A high
abundance of close and contact binaries is expected in some scenarios for the
evolution of binary Kuiper Belt objects.Comment: 15 text pages,6 figures(Color),5 Tables, Accepted to AJ for May 200
SiPM and front-end electronics development for Cherenkov light detection
The Italian Institute of Nuclear Physics (INFN) is involved in the
development of a demonstrator for a SiPM-based camera for the Cherenkov
Telescope Array (CTA) experiment, with a pixel size of 66 mm. The
camera houses about two thousands electronics channels and is both light and
compact. In this framework, a R&D program for the development of SiPMs suitable
for Cherenkov light detection (so called NUV SiPMs) is ongoing. Different
photosensors have been produced at Fondazione Bruno Kessler (FBK), with
different micro-cell dimensions and fill factors, in different geometrical
arrangements. At the same time, INFN is developing front-end electronics based
on the waveform sampling technique optimized for the new NUV SiPM. Measurements
on 11 mm, 33 mm, and 66 mm NUV SiPMs
coupled to the front-end electronics are presentedComment: In Proceedings of the 34th International Cosmic Ray Conference
(ICRC2015), The Hague, The Netherlands. All CTA contributions at
arXiv:1508.0589
Are Botanical Biopesticides Safe for Bees (Hymenoptera, Apoidea)?
The recent global decline in insect populations is of particular concern for pollinators. Wild and managed bees (Hymenoptera, Apoidea) are of primary environmental and economic importance because of their role in pollinating cultivated and wild plants, and synthetic pesticides are among the major factors contributing to their decline. Botanical biopesticides may be a viable alternative to synthetic pesticides in plant defence due to their high selectivity and short environmental persistence. In recent years, scientific progress has been made to improve the development and effectiveness of these products. However, knowledge regarding their adverse effects on the environment and non-target species is still scarce, especially when compared to that of synthetic products. Here, we summarize the studies concerning the toxicity of botanical biopesticides on the different groups of social and solitary bees. We highlight the lethal and sublethal effects of these products on bees, the lack of a uniform protocol to assess the risks of biopesticides on pollinators, and the scarcity of studies on specific groups of bees, such as the large and diverse group of solitary bees. Results show that botanical biopesticides cause lethal effects and a large number of sublethal effects on bees. However, the toxicity is limited when comparing the effects of these compounds with those of synthetic compounds
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