The Stability of the orbits of Earth-mass planets in and near the habitable zones of known exoplanetary systems

We have shown that Earth-mass planets could survive in variously restricted regions of the habitable zones (HZs) of most of a sample of nine of the 93 main-sequence exoplanetary systems confirmed by May 2003. In a preliminary extrapolation of our results to the other systems, we estimate that roughly a third of the 93 systems might be able to have Earth-mass planets in stable, confined orbits somewhere in their HZs. Clearly, these systems should be high on the target list for exploration for terrestrial planets. We have reached this conclusion by launching putative Earth-mass planets in various orbits and following their fate with a mixed-variable symplectic integrator

The #VegasStrong Rallying Cry: How a Hashtag Came to Define a City’s Resilience

The mass shooting that occurred in Las Vegas on October 1, 2017, left a place infamous for its neon lights in complete and total darkness. In a city that projects an image of the ideal adult playground, tragedy peels back the facade built by advertising agencies and tourism authorities. The world, perhaps for the first time, was able to see the people behind the image of a sinful strip. During the hours following the horrific events that occurred the night of October 1st, the Las Vegas community came together to grieve, heal, and find a path forward. Using the rallying cry ‘Vegas Strong’, residents across the valley made clear that the event would serve as a reminder of the strength of the city. This message of resilience was spread across the microblogging platform, Twitter. This paper will examine the origin of the hashtag ‘#VegasStrong’ on Twitter as well as the rate at which it was shared in the days following the mass shooting. The role of key influencers in the dissemination of the hashtag is explored. Findings from the study suggest that the widespread use of the tag can be attributed in part to several key influencers who shared tweets with ‘#VegasStrong’ from October 2, 2017, until October 7, 2017. Among the top influencers using the hashtag, there is a notable absence of local government agencies and local officials. I argue that these agencies and individual actors can improve their risk and crisis communications strategy through the early adoption and promotion of a single, unifying hashtag

Habitability of known exoplanetary systems based on measured stellar properties

At present, because of observational selection effects, we know of no exoplanetary systems with any planetary masses close to that of the Earth. We have therefore used computer models to see whether such planets could be dynamically stable in the presence of the more massive planets known to be present, and in particular whether planets with roughly an Earth mass could remain confined to the classical habitable zone (HZ) for long enough for life to have emerged. Measured stellar properties have been used to determine for each system the present location of the HZ. We have also determined the critical distances from the orbit of each giant planet within which an Earth-mass planet would suffer large orbital changes. We then evaluated the present habitability of each and every exoplanetary system by examining the penetration of these critical distances into the HZ. The critical distances can be obtained by extensive computer modelling of an exoplanetary system. This is far too time consuming to apply to all of the 150 or so systems already known, and to keep up with the latest discoveries. Therefore, in earlier work we studied a few systems in great detail, and developed a speedier means of obtaining the critical distances. We summarize this comparatively quick method here. We can then evaluate comparatively quickly the present habitability of each exoplanetary system by examining the penetration of the critical distance(s) into the HZ. The results are encouraging for astrobiology.Comment: Accepted for publication by The Astrophysical Journal. A few revisions have been made following suggestions by the refere

The Impact of the Affordable Care Act (ACA) on Oral Health in Low-Income Individuals

Most low-income families struggle with financial stability making it difficult to access the health care they need. This challenge is especially prevalent for individuals trying to seek dental care services. Low-income households with limited health insurance coverage often perceive dental care as a luxury. However, good oral health signifies good overall health and can prevent future health problems. One of the primary goals of the Affordable Care Act (ACA) was to increase dental care access for low-income individuals. The ACA was designed to expand dental coverage to be more comprehensive and decrease individuals’ financial burdens. The current study uses research and scholarly review articles from the past seven years to understand whether expanding dental care coverage through the ACA leads to better oral health for low-income individuals. The study shows that because of the ACA, there is a strong correlation between low-income individuals seeking dental care and improving their oral health. Extending dental coverage by the ACA significantly decreases the financial barrier for individuals and allows them to consult with a dentist more often. In addition, routine dental visits provide patients with proper oral health knowledge. The implementation of the ACA is also decreasing the number of emergency dental visits since individuals can access dental check-ups and prevent those visits. Further research is needed to understand how enrollees are utilizing all the benefits the Act provides for. Ensuring the ACA remains in place will allow future generations access to dental care, have better oral health, and reduce the strain on emergency dental departments

Cuff-less continuous blood pressure monitoring system using pulse transit time techniques

This paper describes the development of a continuous cuff-less blood pressure system based on the pulse transit time (PTT) technique. In this study, PTT is defined by two different approaches denoted as PTT1 and PTT2. PTT1 is the time difference between the R-wave peak of the Electrocardiogram (ECG) and the peak of the Photoplethysmogram (PPG). PTT2 is the time difference between two peak PPG signals on same cardiac cycle at different positions on the body. The ECG is acquired on the chest using 3 lead electrodes and a reflection mode optical sensor is deployed on brachial artery and fingertip to monitor the PPGs. These data were synchronized using a National Instruments data acquisition card along with Matlab software for subsequent analysis. A wrist-type cuff-based blood pressure device was used to measure blood pressure on the right hand. Brachial blood pressure was measured on the upper left arm using oscillometric blood pressure monitor. Experiments were conducted by elevating the right hand at different position to investigate variability of PTT under the effects of hydrostatic pressure. Next the variability of PTT due to blood pressure changes during a Valsalva maneuver was investigated. The result shows that the PTT1 is inversely proportional to blood pressure in both experiments. Meanwhile, there is weak correlation between PTT2 and blood pressure measurement which suggests that by excluding the pre-ejection period (PEP) time in PTT calculation may reduce the accuracy of PTT for blood pressure measurement. In conclusion, PTT measurement between ECG and PPG signals has potential to be a reliable technique for cuff-less blood pressure measurement

Development of tubular cardiovascular phantom system for pulse transit time simulation

This paper presents on the development of a tubular cardiovascular phantom system to simulate pulse transit time (PTT). The PTT defined as the delay time between two pulses in one cardiac cycle has been shown to be promising method for cuffless continuous blood pressure (BP) measurement. However most of the PTT measurement was performed on human subjects, thus giving a difficulty in validating sensor performance due to variability of BP. Therefore, a cardiovascular phantom system was proposed for simulate the PTT measurement. An electronic controlled module was developed to control pump operation for pulse generation. Plastic optical fibre (POF) sensors were used to measure the pulse signal on the flexible tube and the results were compared with an in-line pressure sensor. In this experiment, the delay time between two pulses were calculated offline using Matlab software and correlated with pulse pressure. The result demonstrate that the pulse delay time recorded by both sensors decreased with increase of pulse rate and pulse pressure. These results on the phantom study showed similar pattern to the human model, thus indicating that the system is able to simulate PTT for sensor validation purposes

The Ohio State University Counseling Center: Historical Sketches, 1941-1969

Prepared for the Centennial of The Ohio State University

Regional Assessment of GCM-Simulated Current Climate over Northern Canada

Several international Global Climate Models (GCMs) are evaluated on their ability to simulate the mean values and spatial variability of current (1961–90) temperature and precipitation over four regions across Canada’s North. A number of observed climate data sets for Arctic Canada are also assessed. Results reveal a close correspondence, particularly for temperature, among the four observed climate data sets assessed. However, the various GCM simulations of this observed climate show considerable inter-regional and seasonal variability, with temperature more accurately simulated than precipitation. Temperature findings indicate that the British HadCM3, German ECHAM4, and Japanese CCSR-98 models best replicate annual and seasonal values over all sub-regions. The Canadian CGCM2 and U.S. NCAR-PCM models have intermediate accuracy, and the Australian CSIRO-Mk2b and U.S. GFDL-R30 models are least representative. Temperature simulations from the various GCMs collectively display a similar degree of accuracy over all sub-regions, with no clear evidence of superiority in any given area. Precipitation, conversely, is accurately simulated by the majority of models only over northern Quebec/Labrador. All GCMs substantially overestimate annual and seasonal precipitation amounts in the western and central Canadian Arctic.Plusieurs modèles de climats du globe (MCG) internationaux ont été évalués quant à leur aptitude à simuler les valeurs moyennes et la variabilité spatiale de températures et de précipitations récentes (1961-1990) dans quatre régions du Nord canadien. Certains ensembles de données sur le climat observé dans l’Arctique canadien sont également évalués. Les résultats révèlent une correspondance étroite, surtout pour ce qui est de la température, entre les quatre ensembles de données de climats observés qui font l’objet d’une évaluation. Cependant, les diverses simulations de MCG quant au climat observé affichent une grande variabilité entre les régions et les saisons, les températures faisant l’objet de simulations plus précises que les précipitations. Les constatations en matière de précipitations laissent supposer que les modèles HadCM3 britannique, ECHAM4 allemand et CCSR-98 japonais répliquent mieux les valeurs annuelles et saisonnières dans toutes les sous-régions. Pour leur part, les modèles CGCM2 canadien et NCAR-PCM américain présentent une exactitude intermédiaire, tandis que les modèles CSIRO-Mk2b australien et GFDL-R30 américain sont les modèles les moins représentatifs. Ensemble, les simulations de températures des divers modèles MCG affichent un degré semblable d’exactitude dans toutes les sous-régions, sans qu’il n’y ait de modèle nettement supérieur dans une région donnée. Réciproquement, les précipitations sont simulées avec exactitude par la majorité des modèles dans le nord du Québec et le Labrador seulement. Tous les MCG surestiment, de manière substantielle, les quantités de précipitations annuelles et saisonnières dans l’ouest et dans le centre de l’Arctique canadien

Measuring Risk from IT Initiatives Using Implied Volatility

We propose an underrecognized measure to capture changes in firm risk from information technology (IT) announcements: implied volatility (IV) from a firm’s exchange-traded options. An IV is obtained from a priced stock option and represents the option market’s expectation of the firm’s average stock return volatility over the remaining duration of the option. Using the change in IV around IT announcements, we can directly assess changes in IT-induced firm risk. IVs are straightforward to obtain, and are forward-looking based on option market investors’ estimates of future stock return volatility. They do not rely on historical volatility that is confounded with other events. In addition, options have different expiration dates—each with an IV—allowing us to distinguish between short- and long-term risk. We show how a change in IV can be employed to assess changes in short- and long-term firm risk from IT announcements and demonstrate this methodological innovation empirically using a set of IT announcements that have been utilized in previous studies

Estimation of stratospheric input to the Arctic troposphere: 7Be and 10Be in aerosols at Alert, Canada

Concentrations of 7Be and 210Pb in 2 years of weekly high-volume aerosol samples collected at Alert, Northwest Territories, Canada, showed pronounced seasonal variations. We observed a broad winter peak in 210Pb concentration and a spring peak in 7Be. These peaks were similar in magnitude and duration to previously reported results for a number of stations in the Arctic Basin. Beryllium 10 concentrations (determined only during the first year of this study) were well correlated with those of 7Be; the atom ratio 10Be/7Be was nearly constant at 2.2 throughout the year. This relatively high value of 10Be/7Be indicates that the stratosphere must constitute an important source of both Be isotopes in the Arctic troposphere throughout the year. A simple mixing model based on the small seasonal variations of 10Be/7Be indicates an approximately twofold increase of stratospheric influence in the free troposphere in late summer. The spring maxima in concentrations of both Be isotopes at the surface apparently reflect vertical mixing in rather than stratospheric injections into the troposphere. We have merged the results of the Be-based mixing model with weekly O3 soundings to assess Arctic stratospheric impact on the surface O3 budget at Alert. The resulting estimates indicate that stratospheric inputs can account for a maximum of 10-15% of the 03 at the surface in spring and for less during the rest of the year. These estimates are most uncertain during the winter. The combination of Be isotopic measurements and O3 vertical profiles could allow quantification of the contributions of O3 from the Arctic stratosphere and lower latitude regions to the O3 budget in the Arctic troposphere. Although at present the lack of a quantitative understanding of the temporal variation of O3 lifetime in the Arctic troposphere precludes making definitive calculations, qualitative examples of the power of this approach are given