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Heller R.,Leibniz Institute for Astrophysics Potsdam | Leconte J.,Ecole Normale Superieure de Lyon | Barnes R.,University of Washington | Barnes R.,United Virtual
Astronomy and Astrophysics | Year: 2011

Context: Stellar insolation has been used as the main constraint on a planet's potential habitability. However, as more Earth-like planets are discovered around low-mass stars (LMSs), a re-examination of the role of tides on the habitability of exoplanets has begun. Those studies have yet to consider the misalignment between a planet's rotational axis and the orbital plane normal, i.e. the planetary obliquity. Aims. This paper considers the constraints on habitability arising from tidal processes due to the planet's spin orientation and rate. Since tidal processes are far from being understood we seek to understand differences between commonly used tidal models. Methods. We apply two equilibrium tide theories - a constant-phase-lag model and a constant-time-lag model - to compute the obliquity evolution of terrestrial planets orbiting in the habitable zones around LMSs. The time for the obliquity to decrease from an Earth-like obliquity of 23.5° to 5°, the "tilt erosion time", is compared to the traditional insolation habitable zone (IHZ) in the parameter space spanned by the semi-major axis a, the eccentricity e, and the stellar mass Ms. We also compute tidal heating and equilibrium rotation caused by obliquity tides as further constraints on habitability. The Super-Earth Gl581 d and the planet candidate Gl581 g are studied as examples for these tidal processes. Results. Earth-like obliquities of terrestrial planets in the IHZ around stars with masses ≲ 0.25 M ⊙ are eroded in less than 0.1 Gyr. Only terrestrial planets orbiting stars with masses ≳ 0.9 M⊙ experience tilt erosion times larger than 1 Gyr throughout the IHZ. Tilt erosion times for terrestrial planets in highly eccentric orbits inside the IHZ of solar-like stars can be ≲ 10 Gyr. Terrestrial planets in the IHZ of stars with masses ≲ 0.25 M⊙ undergo significant tidal heating due to obliquity tides, whereas in the IHZ of stars with masses ≳ 0.5 M⊙ they require additional sources of heat to drive tectonic activity. The predictions of the two tidal models diverge significantly for e ≳ 0.3. In our two-body simulations, Gl581 d's obliquity is eroded to 0° and its rotation period reached its equilibrium state of half its orbital period in < 0.1 Gyr. Tidal surface heating on the putative Gl581 g is ≲ 150 mW/m2 as long as its eccentricity is smaller than 0.3. Conclusions. Obliquity tides modify the concept of the habitable zone. Tilt erosion of terrestrial planets orbiting LMSs should be included by atmospheric modelers. Tidal heating needs to be considered by geologists. © ESO, 2011.


Latifi K.,United Virtual
Telemedicine journal and e-health : the official journal of the American Telemedicine Association | Year: 2011

The Ministry of Health of Kosova has recently announced the Telemedicine Program of Kosova (TMPK) as the official institution responsible for managing and coordinating the nation's Long-Distance Continuous Medical Education (CME) program. There are a lack of studies on cost-benefit analysis (CBA) and other economic evaluations of telemedicine programs (TMP), in particular the financial value of CME offered through such a service. In addition, there is lack of prospective studies on Monitoring & Evaluation (M&E) of TMP. The goal of this study was to conduct a retrospective CBA of prospective data collected at TMPK over a 5-year period (2005-2010) in order to determine the cost benefit as opposed to the alternative method of delivery of this model for developing countries whose healthcare systems are in disarray. We reviewed data on the number of participants in virtual lectures both at the Telemedicine Center of Kosova (TCK) as well as the number of participants at six Regional Telemedicine Centers throughout Kosova, the number of lectures broadcasted, the clinical cases reviewed and transmitted for international consultation, and other quantitative data. Results: Only in 2009, approximately 2,000 CME certificates were awarded to physicians and nurses of Kosova, 18 international teleconsultations were conducted, 138 videoconferences, lectures, and seminars were held, and there were over 9,000 visitors at the TCK e-library. Data analysis shows that the TMPK has been an efficient mechanism for CME and sustainable model for rebuilding the medical system. TMPK has been successful in offering physicians, nurses, and other medical professions access to electronic information. TMP is an efficient mechanism to ensure CME and rebuilding medical systems in developing countries. There is a need for prospective CBA of any TMP and the establishment of M&E programs in any future telemedicine initiatives in developing countries.


Kopparapu R.K.,Pennsylvania State University | Kopparapu R.K.,United Virtual | Kasting J.F.,Pennsylvania State University | Kasting J.F.,United Virtual | Zahnle K.J.,NASA
Astrophysical Journal | Year: 2012

The hot-Jupiter WASP-12b is a heavily irradiated exoplanet in a short-period orbit around a G0-star with twice the metallicity of the Sun. A recent thermochemical equilibrium analysis based on Spitzer and ground-based infrared observations suggests that the presence of CH4 in its atmosphere and the lack of H2O features can only be explained if the carbon-to-oxygen ratio in the planet's atmosphere is much greater than the solar ratio ([C]/[O] = 0.54). Here, we use a one-dimensional photochemical model to study the effect of disequilibrium chemistry on the observed abundances of H2O, CO, CO2, and CH4 in the WASP-12b atmosphere. We consider two cases: one with solar [C]/[O] and another with [C]/[O] = 1.08. The solar case predicts that H2O and CO are more abundant than CO2 and CH4, as expected, whereas the high [C]/[O] model shows that CO, C2H2, and HCN are more abundant. This indicates that the extra carbon from the high [C]/[O] model is in hydrocarbon species. H2O photolysis is the dominant disequilibrium mechanism that alters the chemistry at higher altitudes in the solar [C]/[O] case, whereas photodissociation of C2H2 and HCN is significant in the super-solar case. Furthermore, our analysis indicates that C2H2 is the major absorber in the atmosphere of WASP-12b and the absorption features detected near 1.6 and 8 μm may be arising from C2H2 rather than CH4. The Hubble Space Telescope's WFC3 can resolve this discrepancy, as C2H2 has absorption between 1.51 and 1.54 μm, while CH4 does not. © 2012. The American Astronomical Society. All rights reserved.


Ross C.S.,United Virtual | Ostroff J.,United Virtual | Jernigan D.H.,Center on Alcohol Marketing and Youth
Journal of Public Health Policy | Year: 2014

Underage alcohol use is a global public health problem and alcohol advertising has been associated with underage drinking. The alcohol industry regulates itself and is the primary control on alcohol advertising in many countries around the world, advising trade association members to advertise only in adult-oriented media. Despite high levels of compliance with these self-regulatory guidelines, in several countries youth exposure to alcohol advertising on television has grown faster than adult exposure. In the United States, we found that exposure for underage viewers ages 18-20 grew from 2005 through 2011 faster than any adult age group. Applying a method adopted from a court in the US to identify underage targeting of advertising, we found evidence of targeting of alcohol advertising to underage viewers ages 18-20. The court's rule appeared in Lockyer v. Reynolds (The People ex rel. Bill Lockyer v. R.J. Reynolds Tobacco Company, GIC764118, 2002). We demonstrated that alcohol companies were able to modify their advertising practices to maintain current levels of adult advertising exposure while reducing youth exposure. © 2014 Macmillan Publishers Ltd.


Dolan S.,United Virtual
Air and Waste Management Association - Air Quality Measurement Methods and Technology Conference 2016 | Year: 2016

In cases where longer visible emissions observations are required at a facility, the use of ALT 082 Digital Camera Opacity Technique is invaluable. The creation of EPA ALT 082 Digital Camera Opacity Technique is a revolution in the regulation of opacity, however new benefits are presenting themselves in the ever-changing regulatory landscape. Many studies, including several EPA Method 301 comparisons, have shown the applicability of ALT 082 and its abilities within regulatory framework. This paper has investigated the use of stationary security cameras for the use of long-duration visible emissions observations, as required by the EPA FerroAlloy NESHAP in 2015. As regulations constantly change, the ALT 082 DOCS II system has to change in concert. As a third party monitoring system, its aim is to benefit both industry and regulators. As regulators place more stringent monitoring requirements on facilities, adopting a new monitoring system is an important way for industry to alleviate the added stress of the new monitoring. Using EPA ALT 082 technique with stationary cameras on-site at a facility allows both industry and regulators immense benefits. Regulators receive to possibility of constant monitoring at any time of day, and industry allows one of their employees to focus on his main job, instead of taking time out to complete one hour or more of visible emissions observations. Increased regulation does not always have to result in more stress for industry. ALT 082, DOCS II, and stationary cameras are the path to high level, low impact visible emissions monitoring.


Kopparapu R.K.,Pennsylvania State University | Kopparapu R.K.,United Virtual | Barnes R.,University of Washington | Barnes R.,United Virtual
Astrophysical Journal | Year: 2010

We study the dynamical stability of planetary systems consisting of one hypothetical terrestrial-mass planet (1 or 10 M ⊕) and one massive planet (10 M ⊕-10 M jup). We consider masses and orbits that cover the range of observed planetary system architectures (including non-zero initial eccentricities), determine the stability limit through N-body simulations, and compare it to the analytic Hill stability boundary. We show that for given masses and orbits of a two-planet system, a single parameter, which can be calculated analytically, describes the Lagrange stability boundary (no ejections or exchanges) but diverges significantly from the Hill stability boundary. However, we do find that the actual boundary is fractal, and therefore we also identify a second parameter which demarcates the transition from stable to unstable evolution. We show the portions of the habitable zones (HZs) of ρ CrB, HD164922, GJ 674, and HD7924 that can support a terrestrial planet. These analyses clarify the stability boundaries in exoplanetary systems and demonstrate that, for most exoplanetary systems, numerical simulations of the stability of potentially habitable planets are only necessary over a narrow region of the parameter space. Finally, we also identify and provide a catalog of known systems that can host terrestrial planets in their HZs. © 2010. The American Astronomical Society.


Dionisio J.D.N.,Loyola Marymount University | Burns Iii W.G.,United Virtual | Gilbert R.,Loyola Marymount University
ACM Computing Surveys | Year: 2013

Moving from a set of independent virtual worlds to an integrated network of 3D virtual worlds or Metaverse rests on progress in four areas: immersive realism, ubiquity of access and identity, interoperability, and scalability. For each area, the current status and needed developments in order to achieve a functional Metaverse are described. Factors that support the formation of a viable Metaverse, such as institutional and popular interest and ongoing improvements in hardware performance, and factors that constrain the achievement of this goal, including limits in computational methods and unrealized collaboration among virtual world stakeholders and developers, are also considered. © 2013 ACM.


Siegel M.,Boston University | Ross C.S.,United Virtual | King III C.,Greylock McKinnon Associates | King III C.,Pleiades
American Journal of Public Health | Year: 2013

Objectives. We examined the relationship between levels of household firearm ownership, as measured directly and by a proxy-the percentage of suicides committed with a firearm-and age-adjusted firearm homicide rates at the state level. Methods. We conducted a negative binomial regression analysis of panel data from the Centers for Disease Control and Prevention's Web-Based Injury Statistics Query and Reporting Systems database on gun ownership and firearm homicide rates across all 50 states during 1981 to 2010. We determined fixed effects for year, accounted for clustering within states with generalized estimating equations, and controlled for potential state-level confounders. Results. Gun ownership was a significant predictor of firearm homicide rates (incidence rate ratio = 1.009; 95% confidence interval = 1.004, 1.014). This model indicated that for each percentage point increase in gun ownership, the firearm homicide rate increased by 0.9%. Conclusions. We observed a robust correlation between higher levels of gun ownership and higher firearm homicide rates. Although we could not determine causation, we found that states with higher rates of gun ownership had disproportionately large numbers of deaths from firearm-related homicides. Copyright © 2013 by the American Public Health Association®.


Dixon R.F.,Massachusetts General Hospital | Dixon R.F.,United Virtual
Health Affairs | Year: 2010

The effective delivery of primary care requires more frequent information exchange and communication than the typical office visit allows. Although industry leaders endorse health information technology (IT) to improve health outcomes and reduce costs, there has been less attention devoted to the use of this technology to deliver care. Using Internet-based technologies such as secure messaging, videoconferencing, and remote physiological monitoring can provide information to improve the patient-provider relationship and the quality of health care. Evidence has shown that patients and providers are willing to use these care delivery technologies. However, their success will require integration with electronic health records and payment models that support their implementation and growth. ©2010 Project HOPE - The People-to-People Health Foundation, Inc.


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