Lorentz invariance violation introduced as a generic modification to particle dispersion relations is used to study high energy cosmic ray attenuation processes. It is shown to reproduce the same ...physical effects for vacuum Cherenkov radiation, as in some particular models with spontaneous breaking of Lorentz symmetry. This approximation is also implemented for the study of photon decay in vacuum, where stringent limits to the violation scale are derived from the direct observation of very high energy cosmic ray photon events on gamma telescopes. Photo production processes by cosmic ray primaries on photon background are also addressed, to show that Lorentz violation may turn off this attenuation process at energies above a well-defined secondary threshold.
Among the most studied approaches to introduce the breaking of Lorentz symmetry, the generic approach is one of the most frequently used for phenomenology, it converges on the modification of the ...free particle dispersion relation. Using this approach in the photon sector, we have calculated the squared probability amplitude for vacuum Cherenkov radiation and photon decay by correcting the QED coupling at tree level and first order in LIV parameters. For the lower order energy correction we calculate the emission and decay rate for each process.
One of the most studied approaches in phenomenology to introduce the breaking of Lorentz symmetry is the generic approach. This consist on the modification of the free particle dispersion relation by ...the addition of an extra power law term of order n on energy or momentum. Using this approach in the photon sector, we have calculated the generic rates for vacuum Cherenkov radiation and photon decay, for any order n, at leading order. Explicit results for the decay and emission rates for the lowest values of n are also presented.
Background. The community outbreak of legionnaires disease that occurred in Murcia, Spain, in July 2001—to our knowledge, the largest such outbreak ever reported—afforded an unusual opportunity to ...compare the clinical response of patients with Legionella pneumonia treated with levofloxacin with that of patients treated with macrolides and to determine the role of rifampicin combined with levofloxacin in treating severe legionellosis. Methods. An observational, prospective, nonrandomized study was conducted involving 292 patients seen at our hospital (Hospital “J. M. Morales Meseguer”; Murcia, Spain) who received a diagnosis of Legionella pneumonia during the Murcia outbreak. To compare both antibiotic regimens (macrolides vs. levofloxacin), patients were stratified by the severity of pneumonia. Duration of fever, clinical outcome, complications, side effects, and length of hospital stay were recorded. To assess the potential effects of adjuvant therapy with rifampicin, 45 case patients treated with levofloxacin plus rifampicin were evaluated and compared with 45 control pairs who were treated with levofloxacin alone. Results. With the exception of 2 patients who died, all patients were cured. There were no significant differences between treatment groups in clinical outcome for patients with mild-to-moderate pneumonia. Nevertheless, in patients with severe pneumonia, levofloxacin exerted superior activity; it was associated with fewer complications (3.4% of patients receiving levofloxacin experienced complications, compared with 27.2% of patients receiving macrolides; P =.02) and shorter mean hospital stays (5.5 vs. 11.3 days; P =.04). Addition of rifampicin to the treatment regimen for patients receiveing levofloxacin for severe pneumonia provides no additional benefit. Conclusions. Our findings strongly suggest that monotherapy with levofloxacin is a safe and effective treatment for legionnaires disease, including in patients with severe disease. In these patients, levofloxacin appears to be more effective than clarithromycin.
Chicanos/Latinos comprise the largest racial and ethnic population in the U.S. public K-12 schools, yet hold some of the largest rates of academic underperformance in high school and college ...completion. This study aims at understanding the academic trajectories of five Chicano/Latino males and their decision to enlist in the military after high school graduation. Using in-depth semistructured interviews, participants discussed the role that high school structures, family, social capital, and sociocultural forces played in their career decision-making process. Results showed that students viewed the military as a way of upward social mobility and their most viable career option after completing high school. The study also highlights the lack of resources available to students who may not be viewed as college material by school personnel.
The High Altitude Water Cherenkov observatory (HAWC) is an air shower array devised for TeV gamma-ray astronomy. HAWC is located at an altitude of 4100 m a.s.l. in Sierra Negra, Mexico. HAWC consists ...of 300 Water Cherenkov Detectors, each instrumented with 4 photomultiplier tubes (PMTs). HAWC re-uses the Front-End Boards from the Milagro experiment to receive the PMT signals. These boards are used in combination with Time to Digital Converters (TDCs) to record the time and the amount of light in each PMT hit (light flash). A set of VME TDC modules (128 channels each) is operated in a continuous (dead time free) mode. The TDCs are read out via the VME bus by Single-Board Computers (SBCs), which in turn are connected to a gigabit Ethernet network. The complete system produces ≈500 MB/s of raw data. A high-throughput data processing system has been designed and built to enable real-time data analysis. The system relies on off-the-shelf hardware components, an open-source software technology for data transfers (ZeroMQ) and a custom software framework for data analysis (AERIE). Multiple trigger and reconstruction algorithms can be combined and run on blocks of data in a parallel fashion, producing a set of output data streams which can be analyzed in real time with minimal latency (<5 s). This paper provides an overview of the hardware set-up and an in-depth description of the software design, covering both the TDC data acquisition system and the real-time data processing system. The performance of these systems is also discussed.
Using a 1:1 cocrystal of (E)‐N‐(3,4‐difluorophenyl)‐1‐(pyridin‐4‐yl)methanimine with acetic acid, C12H8F2N2·C2H4O2, we investigate the influence of F atoms introduced to the aromatic ring on ...promoting π–π interactions. The cocrystal crystallizes in the triclinic space group P1. Through crystallographic analysis and computational studies, we reveal the molecular arrangement within this cocrystal, demonstrating the presence of hydrogen bonding between the acetic acid molecule and the pyridyl group, along with π–π interactions between the aromatic rings. Our findings highlight the importance of F atoms in promoting π–π interactions without necessitating full halogenation of the aromatic ring.
Using a cocrystal of a molecule that does not crystallize, we reveal that π–π interactions between aromatic rings are present with only two F atoms in the aromatic ring.
Academic probation policies and practices can help or hinder students' persistence in reaching college degrees or certificates in community college. The stakes are high for Latino/x men in community ...colleges as they attempt to balance multiple internal and external demands that may impact academic performance. This practice brief provides recommendations for faculty, counselors, and other institutional agents to tackle academic probation to support Latino/x community college men's educational goals.
Introduction
The use of Vape has increased during the pandemic due to the changes generated by it. Currently we have finished the conditions of confinement, so it is important to identify
Objective: ...To determine the factors associated with post-COVID-19 confinement vape consumption in young adults
Methods
A cross-sectional, prospective study was carried out between January and April 2022, including men and women residents of Veracruz aged between 18 and 35 years, excluding participants with addiction treatment or with a diagnosis of a lung disease. A survey was applied through Google Forms to identify the factors associated with Vape consumption after confinement by COVID-19, including depression, anxiety and stress evaluated with the DASS-21 instrument (Cronbach's alpha between 0.79 and 0.87). For data analysis, SPSS v22 software was used, X2 test with Odds Ratio (OR) and 95% confidence interval (CI95%) and MannWhitney U test, assigning statistical significance with p < 0.05.
Results
514 participants were included, with a prevalence of vape use of 28.5%. Physical activity, cigarette consumption by a family member, levels of anxiety, depression and stress showed a value of p > 0.05 for Vape consumption, while other factors (OR/95%CI) such as being female (0.6/0.4-0.9), identifying vape advertising on Facebook (0.35/0.19-0.65), having a family member who vapes (2.4/1.5-3.6), consuming cigarettes (4.2/2.7-6.4) and identifying vape advertising on Instagram (1.5/ 1.0-2.3) had values of p < 0.05
Conclusions
Post-pandemic vape use is not affected by anxiety, stress or depression, identifying other factors that favor its use such as the environment in which it develops, such as being someone with a history of tobacco use, in addition to the family smoker and advertising on Instagram, which is a social network that often works as an aspirational image for users, a situation contrary to what is shown on Facebook.
Key messages
* Vape consumption continues to be a post-pandemic public health problem, so it is necessary to reinforce educational measures on the subject and the post-Covid complications of its use.
* It is necessary to regulate vape advertising on social networks, as has been done with tobacco in different countries, since it can become a risk factor by showing aspirational images for users.
The Crab Nebula is the brightest TeV gamma-ray source in the sky and has been used for the past 25 years as a reference source in TeV astronomy, for calibration and verification of new TeV ...instruments. The High Altitude Water Cherenkov Observatory (HAWC), completed in early 2015, has been used to observe the Crab Nebula at high significance across nearly the full spectrum of energies to which HAWC is sensitive. HAWC is unique for its wide field of view, nearly 2 sr at any instant, and its high-energy reach, up to 100 TeV. HAWC's sensitivity improves with the gamma-ray energy. Above ∼1 TeV the sensitivity is driven by the best background rejection and angular resolution ever achieved for a wide-field ground array. We present a time-integrated analysis of the Crab using 507 live days of HAWC data from 2014 November to 2016 June. The spectrum of the Crab is fit to a function of the form . The data is well fitted with values of = 2.63 0.03, β = 0.15 0.03, and when E0 is fixed at 7 TeV and the fit applies between 1 and 37 TeV. Study of the systematic errors in this HAWC measurement is discussed and estimated to be 50% in the photon flux between 1 and 37 TeV. Confirmation of the Crab flux serves to establish the HAWC instrument's sensitivity for surveys of the sky. The HAWC all-sky survey will be the deepest survey of the northern sky ever conducted in the multi-TeV band.
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