2,131 research outputs found

    Detection of Diatomic Carbon in 2I/Borisov

    Get PDF
    2I/Borisov is the first-ever observed interstellar comet (and the second detected interstellar object (ISO)). It was discovered on 2019 August 30 and has a heliocentric orbital eccentricity of ~3.35, corresponding to a hyperbolic orbit that is unbound to the Sun. Given that it is an ISO, it is of interest to compare its properties—such as composition and activity—with the comets in our solar system. This study reports low-resolution optical spectra of 2I/Borisov. The spectra were obtained by the MDM Observatory Hiltner 2.4 m telescope/Ohio State Multi-Object Spectrograph (on 2019 October 31.5 and November 4.5, UT). The wavelength coverage spanned from 3700 to 9200 Å. The dust continuum reflectance spectra of 2I/Borisov show that the spectral slope is steeper in the blue end of the spectrum (compared to the red). The spectra of 2I/Borisov clearly show CN emission at 3880 Å, as well as C2 emission at both 4750 and 5150 Å. Using a Haser model to covert the observed fluxes into estimates for the molecular production rates, we find Q(CN) = 2.4 ± 0.2 × 10²⁴ s⁻¹, and Q(C₂) = (5.5 ± 0.4) × 10²³ s⁻¹ at the heliocentric distance of 2.145 au. Our Q(CN) estimate is consistent with contemporaneous observations, and the Q(C₂) estimate is generally below the upper limits of previous studies. We derived the ratio Q(C₂)/Q(CN) = 0.2 ± 0.1, which indicates that 2I/Borisov is depleted in carbon-chain species, but is not empty. This feature is not rare for the comets in our solar system, especially in the class of Jupiter-family comets

    Detection of Diatomic Carbon in 2I/Borisov

    Get PDF
    2I/Borisov is the first-ever observed interstellar comet (and the second detected interstellar object (ISO)). It was discovered on 2019 August 30 and has a heliocentric orbital eccentricity of ~3.35, corresponding to a hyperbolic orbit that is unbound to the Sun. Given that it is an ISO, it is of interest to compare its properties—such as composition and activity—with the comets in our solar system. This study reports low-resolution optical spectra of 2I/Borisov. The spectra were obtained by the MDM Observatory Hiltner 2.4 m telescope/Ohio State Multi-Object Spectrograph (on 2019 October 31.5 and November 4.5, UT). The wavelength coverage spanned from 3700 to 9200 Å. The dust continuum reflectance spectra of 2I/Borisov show that the spectral slope is steeper in the blue end of the spectrum (compared to the red). The spectra of 2I/Borisov clearly show CN emission at 3880 Å, as well as C2 emission at both 4750 and 5150 Å. Using a Haser model to covert the observed fluxes into estimates for the molecular production rates, we find Q(CN) = 2.4 ± 0.2 × 10²⁴ s⁻¹, and Q(C₂) = (5.5 ± 0.4) × 10²³ s⁻¹ at the heliocentric distance of 2.145 au. Our Q(CN) estimate is consistent with contemporaneous observations, and the Q(C₂) estimate is generally below the upper limits of previous studies. We derived the ratio Q(C₂)/Q(CN) = 0.2 ± 0.1, which indicates that 2I/Borisov is depleted in carbon-chain species, but is not empty. This feature is not rare for the comets in our solar system, especially in the class of Jupiter-family comets

    Mild Traumatic Brain Injury in Elderly Patients Receiving Direct Oral Anticoagulants:A Systematic Review and Meta-Analysis

    Get PDF
    The aim of this work was to conduct a systematic review and meta-analysis of studies reporting on the risk of traumatic intracerebral hemorrhage (tICH), the course of tICH, and its treatment and mortality rates in elderly mild traumatic brain injury (mTBI) patients using direct oral anticoagulants (DOACs). We consulted PubMed and Embase for relevant cohort and case-control studies with a control group. Two authors independently selected studies, assessed methodological quality, and extracted outcome data. Estimates were pooled with the Mantel-Haenszel random-effects method. We identified 16 articles comprising 3671 elderly mTBI patients using DOACs. Use of DOACs was associated with a reduced risk of tICH compared to the use of vitamin K antagonists (VKAs; odds ratio [OR], 0.44; 95% confidence interval [CI], 0.29-0.65; I2 = 22%) and a similar risk compared to the use of antiplatelet therapy (APT; OR, 0.98; 95% CI, 0.39-2.44; I2 = 0%). Reversal agent use and neurosurgical intervention rate were lower in patients using DOACs compared to patients using VKAs (OR, 0.10; 95% CI, 0.06-0.16; I2 = 0% and OR, 0.37; 95% CI, 0.21-0.67; I2 = 0%, respectively). There was no significant difference in neurosurgical intervention rate between patients who used DOACs versus patients who used APT (OR, 0.58; 95% CI, 0.15-2.21; I2 = 41%) or no antithrombotic therapy (OR, 0.76; 95% CI, 0.20-2.86; I2 = 23%). ICH progression, risk of delayed ICH, and TBI-related in-hospital mortality were comparable among treatment groups. The present study indicates that elderly patients using DOACs have a lower risk of adverse outcome compared to patients using VKAs and a similar risk compared to patients using APT after mTBI

    Tobacco Use, Exposure to Secondhand Smoke, and Training on Cessation Counseling Among Nursing Students: Cross-Country Data from the Global Health Professions Student Survey (GHPSS), 2005–2009

    Get PDF
    The Nursing Global Health Professions Student Survey (GHPSS) has been conducted in schools in 39 countries and the Gaza Strip/West Bank (identified as “sites” for the remainder of this paper). In half the sites, over 20% of the students currently smoked cigarettes, with males having higher rates than females in 22 sites. Over 60% of students reported having been exposed to secondhand smoke in public places in 23 of 39 sites. The majority of students recognized that they are role models in society, believed they should receive training on counseling patients to quit using tobacco, but few reported receiving any formal training. Tobacco control efforts must discourage tobacco use among health professionals, promote smoke free workplaces, and implement programs that train health professionals in effective cessation-counseling techniques
    corecore