3,870 research outputs found
TeV gravity at neutrino telescopes
Cosmogenic neutrinos reach the Earth with energies around 10^9 GeV, and their
interactions with matter will be measured in upcoming experiments (Auger,
IceCube). Models with extra dimensions and the fundamental scale at the TeV
could imply signals in these experiments. In particular, the production of
microscopic black holes by cosmogenic neutrinos has been extensively studied in
the literature. Here we make a complete analysis of gravity-mediated
interactions at larger distances, where they can be calculated in the eikonal
approximation. In these processes a neutrino of energy E_\nu interacts
elastically with a parton inside a nucleon, loses a small fraction y of its
energy, and starts a hadronic shower of energy y E_\nu << E_\nu. We analyze the
ultraviolet dependence and the relevance of graviton emission in these
processes, and show that they are negligible. We also study the energy
distribution of cosmogenic events in AMANDA and IceCube and the possibility of
multiple-bang events. For any neutrino flux, the observation of an enhanced
rate of neutral current events above 100 TeV in neutrino telescopes could be
explained by TeV-gravity interactions. The values of the fundamental scale of
gravity that IceCube could reach are comparable to those to be explored at the
LHC.Comment: 10 pages, 7 figures; new section on air showers added, version to be
publishe
Constraining new physics scenarios in neutrino oscillations from Daya Bay data
We perform for the first time a detailed fit to the disappearance data of the Daya Bay experiment to constrain the parameter
space of models where sterile neutrinos can propagate in a large compactified
extra dimension (LED) and models where non-standard interactions affect the
neutrino production and detection (NSI). We find that the compactification
radius in LED scenarios can be constrained at the level of
for normal ordering and of for inverted ordering, at 2
confidence level. For the NSI model, reactor data put a strong upper bound on
the parameter at the level of , whereas the
main effect of and is a worsening of
the determination of .Comment: 5 pages, 2 figure
Probing TeV gravity at neutrino telescopes
Models with extra dimensions and the fundamental scale at the TeV could imply
sign als in large neutrino telescopes due to gravitational scattering of
cosmogenic neu trinos in the detection volume. Apart from the production of
microscopic black hol es, extensively studied in the literature, we present
gravity-mediated interactions at larger distances, that can be calculated in
the e ikonal approximation. In these elastic processes the neutrino loses a
small fracti on of energy to a hadronic shower and keeps going. The event rate
of these events is higher than that of black hole formation and the signal is
distinct: no charged leptons and possibly multiple-bang events.Comment: 5 pages; to appear in the proceedings of the Workshop on Exotic
Physics with Neutrino Telesocpes, Uppsala 20-22 September 200
Order-disorder phase change in embedded Si nano-particles
We investigated the relative stability of the amorphous vs crystalline
nanoparticles of size ranging between 0.8 and 1.8 nm. We found that, at
variance from bulk systems, at low T small nanoparticles are amorphous and they
undergo to an amorphous-to-crystalline phase transition at high T. On the
contrary, large nanoparticles recover the bulk-like behavior: crystalline at
low T and amorphous at high T. We also investigated the structure of
crystalline nanoparticles, providing evidence that they are formed by an
ordered core surrounded by a disordered periphery. Furthermore, we also provide
evidence that the details of the structure of the crystalline core depend on
the size of the nanoparticleComment: 8 pages, 5 figure
Cosmogenic neutrinos and signals of TeV gravity in air showers and neutrino telescopes
The existence of extra dimensions allows the possibility that the fundamental
scale of gravity is at the TeV. If that is the case, gravity could dominate the
interactions of ultra-high energy cosmic rays. In particular, the production of
microscopic black holes by cosmogenic neutrinos has been estimated in a number
of papers. We consider here gravity-mediated interactions at larger distances,
where they can be calculated in the eikonal approximation. We show that for the
expected flux of cosmogenic neutrinos these elastic processes give a stronger
signal than black hole production in neutrino telescopes. Taking the bounds on
the higher dimensional Planck mass M_D (D=4+n) from current air shower
experiments, for n=2 (6) elastic collisions could produce up to 118 (34) events
per year at IceCube. On the other hand, the absence of any signal would imply a
bound of M_D>~5 TeV.Comment: 10 pages, 1 figure; version to appear in Phys. Rev. Let
Probing new physics scenarios in accelerator and reactor neutrino experiments
We perform a detailed combined fit to the disappearence data of the Daya Bay experiment and the
appearance and disappearance data of the Tokai to Kamioka (T2K) one in the presence
of two models of new physics affecting neutrino oscillations, namely a model
where sterile neutrinos can propagate in a large compactified extra dimension
and a model where non-standard interactions (NSI) affect the neutrino
production and detection. We find that the Daya Bay T2K data
combination constrains the largest radius of the compactified extra dimensions
to be at 2 C.L. (for the inverted
ordering of the neutrino mass spectrum) and the relevant NSI parameters in the
range , for particular choices of
the charged parity violating phases.Comment: 18 pages, 10 figures, 4 tables; typos corrected; matches published
versio
Return to work of breast cancer survivors: Perspectives and challenges for occupational physicians
Breast cancer is one of the most common diseases worldwide, mainly affecting the female gender. Considering the increase of breast cancer incidence and the decrease of mortality due to news diagnostic and therapeutic tools, the return to work issue after treatment is going to be very common in the next years. Occupational physicians therefore need to face the return to work and the fitness for work of workers previously diagnosed with breast cancer with a sufficient cultural and technical background. In addition to individual characteristics preceding the diagnosis, clinical outcome, lifestyles and occupational variables are the most impactful factors on return to work that need to be taken into account. The aim of this work is to analyze these factors and discuss the central role of occupational physicians in the decision-making process of returning to work in breast cancer survivors
Concerns, Perceived Impact, Preparedness in Coronavirus Disease (COVID-19) Pandemic and Health Outcomes among Italian Physicians: A Cross-Sectional Study
Background: Health care workers (HCWs) are among the professionals at serious risk for the impact of the COVID-19 pandemic on their mental health. In this sense, the next public health challenge globally will be to preserving healthy HCWs during this pandemic. Aim: The present study has the aim of investigating the relationship among concerns, perceived impact, preparedness for the COVID-19 pandemic and the mental health of Italian physicians. Methods: From March 29th to April 15th 2020, we conducted an online survey using snowball sampling techniques through Limesurvey platform. Data were analyzed using descriptive statistics and multiple binary logistic regressions. Results: Multivariate analysis showed that the risk factors for perceived job stress were concerns about catching COVID-19 (OR = 3.18 [95% CI = 2.00-5.05] P <.001), perceived impact on job demands (OR = 1.63 [95% CI = 1.05-2.52] P <.05), perceived impact on job role (OR = 2.50 [95% CI = 1.60-3.90] P <.001), and non-working concerns (OR = 1.86 [95% CI = 1.15-3.03] P <.05). With respect to the risk factors for rumination about the pandemic emerged concerns about catching COVID-19 (OR 1.74, [95% CI = 1.12-2.71] P <.05), perceived impact on job role (OR = 1.68 [95% CI = 1.12-2.52] P <.05), and impact on personal life (OR = 2.04 [95% CI = 1.08-3.86] P <.05). Finally, the risk factors for crying at work were perceived impact on job role (OR = 2.47, [95% CI = 1.20-5.09] P <.05), rumination about the pandemic (OR = 3.027 [95% CI = 1.27-7.19] P <.01), watching colleagues crying at work (OR = 3.82 [95% CI = 1.88-7.77] P <.01), and perceived job stress (OR = 3.53 [95% CI = 1.24-10.07] P <.05). Conclusion: In general, our results highlighted that being concerned about being infected/infecting other people, carrying out new and unusual tasks, and witnessing colleagues crying at work were important risk factors for physicians’ well-being. Additional data are necessary to advance understanding of these risk factors in a long-term perspective
Dealing With COVID-19 Patients: A Moderated Mediation Model of Exposure to Patients' Death and Mental Health of Italian Health Care Workers
Introduction: The COVID-19 pandemic is asking health care workers (HCWs) to meet extraordinary challenges. In turn, HCWs were experiencing tremendous psycho-social crisis as they have had to deal with unexpected emotional requirements (ERs) arising from caring for suffering and dying patients on a daily basis. In that context, recent studies have highlighted how HCWs working during the COVID-19 outbreak manifested extreme emotional and behavioral reactions that may have impacted their mental health, increasing the risk for developing post-traumatic stress symptoms. Purpose: The aim of the study was to investigate post-traumatic stress symptoms, such as intrusion symptoms, as a potential mediator of the link between ERs and crying at work, and whether rumination moderates the relationship between ERs and intrusion-based PTS symptoms among HCWs who have had to deal with patients dying from COVID-19. Methods: An online cross-sectional study design was performed. A total of 543 Italian HCWs (physicians and nurses) participated in the study. Participation was voluntary and anonymous. We used the SPSS version of bootstrap-based PROCESS macro for testing the moderated mediation model. Results: ERs had an indirect effect on crying at work through the mediating role of intrusion symptoms. Results from the moderated mediation model showed that rumination moderated the indirect effect of ERs on crying at work via intrusion symptoms, and this effect was significant only for high rumination. Furthermore, when we tested for an alternative model where rumination moderates the direct effect of ERs on crying at work, this moderation was not significant. Conclusions: As the second wave of the COVID-19 pandemic is ongoing, there is an urgent need for decision-makers to rapidly implement interventions aimed at offering timely psychological support to HCWs, especially in those contexts where the risk of emotional labor associated to patients dying from COVID-19 is higher
HPLC-MS/MS method for the detection of selected toxic metabolites produced by Penicillium spp. In nuts
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