862 research outputs found
Outcomes Following Cordotomy by Coblation for Bilateral Vocal Fold Immobility.
Importance: Bilateral vocal fold immobility (BVFI) can result in considerable voice and airway impairment. Although the carbon dioxide (CO2) laser is commonly used in transverse cordotomy, the coblator, a minimally invasive, low-thermal technology, has been increasingly used in otolaryngology.
Objective: To investigate outcomes associated with coblation to treat BVFI.
Design, Setting, and Participants: A retrospective case series was conducted between January 2012 and June 2017 including 19 patients with BVFI who underwent cordotomy by coblation in a single tertiary care institution.
Main Outcomes and Measures: Clinical, operative, and health status data for all patients were reviewed. Quality of life was measured by the EuroQol 5-Dimensions (EQ-5D), and the Voice Handicap Index (VHI) was used to measure vocal cord function.
Results: Nineteen patients were eligible for inclusion, 15 of which underwent cordotomy by coblation for BVFI without stenosis. Mean age was 57 years with 13 (68%) women. The etiology of BVFI included thyroidectomy in 8 (42%) patients and prolonged intubation in 7 (37%). Mean length of surgery for BVFI without stenosis was 17 minutes; mean operating room (OR) time was 63 minutes compared with 88 scheduled OR minutes (effect size, 25 minutes; 95% CI, 9 to 40 minutes). During follow-up, 4 (27%) of these patients developed granulation tissue postoperatively. Following surgery, patient-reported shortness of breath significantly improved, with 10 of 14 (71%; 95% CI, 45% to 88%) patients with some level of preoperative breathing difficulty experiencing improvement in their breathing. Stridor also significantly improved, with 10 of 12 (83%; 95% CI, 55% to 95%) patients with some level of preoperative stridor improved after surgery. The EQ-5D results trended toward improvement postoperatively (0.67 to 0.80; effect size, 0.13; 95% CI, -0.10 to 0.34). The functional (22 to 12; effect size, -10; 95% CI, -19 to -2), emotional (23 to 11; effect size, -12; 95% CI, -23 to -3), and total VHI all significantly improved (68 to 39; effect size, -29; 95% CI, -49 to -8).
Conclusions and Relevance: Initial outcomes of cordotomy by coblation revealed that this technique was a safe and efficient approach to treating BVFI. Coblation was associated with significant reduction in OR time compared with scheduled time, and patients experienced significant improvement in shortness of breath, stridor, and vocal cord function
Transit Timing Observations from Kepler: VII. Confirmation of 27 planets in 13 multiplanet systems via Transit Timing Variations and orbital stability
We confirm 27 planets in 13 planetary systems by showing the existence of
statistically significant anti-correlated transit timing variations (TTVs),
which demonstrates that the planet candidates are in the same system, and
long-term dynamical stability, which places limits on the masses of the
candidates---showing that they are planetary. %This overall method of planet
confirmation was first applied to \kepler systems 23 through 32. All of these
newly confirmed planetary systems have orbital periods that place them near
first-order mean motion resonances (MMRs), including 6 systems near the 2:1
MMR, 5 near 3:2, and one each near 4:3, 5:4, and 6:5. In addition, several
unconfirmed planet candidates exist in some systems (that cannot be confirmed
with this method at this time). A few of these candidates would also be near
first order MMRs with either the confirmed planets or with other candidates.
One system of particular interest, Kepler-56 (KOI-1241), is a pair of planets
orbiting a 12th magnitude, giant star with radius over three times that of the
Sun and effective temperature of 4900 K---among the largest stars known to host
a transiting exoplanetary system.Comment: 12 pages, 13 figures, 5 tables. Submitted to MNRA
Exploring leadership in multi-sectoral partnerships
This article explores some critical aspects of leadership in the context of multi-sectoral partnerships. It focuses on leadership in practice and asks the question, `How do managers experience and perceive leadership in such partnerships?' The study contributes to the debate on whether leadership in a multi-sectoral partnership context differs from that within a single organization. It is based on the accounts of practising managers working in complex partnerships. The article highlights a number of leadership challenges faced by those working in multi-sectoral partnerships. Partnership practitioners were clear that leadership in partnerships was more complex than in single organizations. However, it was more difficult for them to agree a consensus on the essential nature of leadership in partnership. We suggest that a first-, second- and third-person approach might be a way of better interpreting leadership in the context of partnerships
'It's Reducing a Human Being to a Percentage'; Perceptions of Justice in Algorithmic Decisions
Data-driven decision-making consequential to individuals raises important
questions of accountability and justice. Indeed, European law provides
individuals limited rights to 'meaningful information about the logic' behind
significant, autonomous decisions such as loan approvals, insurance quotes, and
CV filtering. We undertake three experimental studies examining people's
perceptions of justice in algorithmic decision-making under different scenarios
and explanation styles. Dimensions of justice previously observed in response
to human decision-making appear similarly engaged in response to algorithmic
decisions. Qualitative analysis identified several concerns and heuristics
involved in justice perceptions including arbitrariness, generalisation, and
(in)dignity. Quantitative analysis indicates that explanation styles primarily
matter to justice perceptions only when subjects are exposed to multiple
different styles---under repeated exposure of one style, scenario effects
obscure any explanation effects. Our results suggests there may be no 'best'
approach to explaining algorithmic decisions, and that reflection on their
automated nature both implicates and mitigates justice dimensions.Comment: 14 pages, 3 figures, ACM Conference on Human Factors in Computing
Systems (CHI'18), April 21--26, Montreal, Canad
Masses, radii, and orbits of small Kepler planets : The transition from gaseous to rocky planets
We report on the masses, sizes, and orbits of the planets orbiting 22 Kepler stars. There are 49 planet candidates around these stars, including 42 detected through transits and 7 revealed by precise Doppler measurements of the host stars. Based on an analysis of the Kepler brightness measurements, along with high-resolution imaging and spectroscopy, Doppler spectroscopy, and (for 11 stars) asteroseismology, we establish low false-positive probabilities (FPPs) for all of the transiting planets (41 of 42 have an FPP under 1%), and we constrain their sizes and masses. Most of the transiting planets are smaller than three times the size of Earth. For 16 planets, the Doppler signal was securely detected, providing a direct measurement of the planet's mass. For the other 26 planets we provide either marginal mass measurements or upper limits to their masses and densities; in many cases we can rule out a rocky composition. We identify six planets with densities above 5 g cm-3, suggesting a mostly rocky interior for them. Indeed, the only planets that are compatible with a purely rocky composition are smaller than 2 R â. Larger planets evidently contain a larger fraction of low-density material (H, He, and H2O).Peer reviewedFinal Accepted Versio
A chemical survey of exoplanets with ARIEL
Thousands of exoplanets have now been discovered with a huge range of masses, sizes and orbits: from rocky Earth-like planets to large gas giants grazing the surface of their host star. However, the essential nature of these exoplanets remains largely mysterious: there is no known, discernible pattern linking the presence, size, or orbital parameters of a planet to the nature of its parent star. We have little idea whether the chemistry of a planet is linked to its formation environment, or whether the type of host star drives the physics and chemistry of the planetâs birth, and evolution. ARIEL was conceived to observe a large number (~1000) of transiting planets for statistical understanding, including gas giants, Neptunes, super-Earths and Earth-size planets around a range of host star types using transit spectroscopy in the 1.25â7.8 ÎŒm spectral range and multiple narrow-band photometry in the optical. ARIEL will focus on warm and hot planets to take advantage of their well-mixed atmospheres which should show minimal condensation and sequestration of high-Z materials compared to their colder Solar System siblings. Said warm and hot atmospheres are expected to be more representative of the planetary bulk composition. Observations of these warm/hot exoplanets, and in particular of their elemental composition (especially C, O, N, S, Si), will allow the understanding of the early stages of planetary and atmospheric formation during the nebular phase and the following few million years. ARIEL will thus provide a representative picture of the chemical nature of the exoplanets and relate this directly to the type and chemical environment of the host star. ARIEL is designed as a dedicated survey mission for combined-light spectroscopy, capable of observing a large and well-defined planet sample within its 4-year mission lifetime. Transit, eclipse and phase-curve spectroscopy methods, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allow us to measure atmospheric signals from the planet at levels of 10â100 part per million (ppm) relative to the star and, given the bright nature of targets, also allows more sophisticated techniques, such as eclipse mapping, to give a deeper insight into the nature of the atmosphere. These types of observations require a stable payload and satellite platform with broad, instantaneous wavelength coverage to detect many molecular species, probe the thermal structure, identify clouds and monitor the stellar activity. The wavelength range proposed covers all the expected major atmospheric gases from e.g. H2O, CO2, CH4 NH3, HCN, H2S through to the more exotic metallic compounds, such as TiO, VO, and condensed species. Simulations of ARIEL performance in conducting exoplanet surveys have been performed â using conservative estimates of mission performance and a full model of all significant noise sources in the measurement â using a list of potential ARIEL targets that incorporates the latest available exoplanet statistics. The conclusion at the end of the Phase A study, is that ARIEL â in line with the stated mission objectives â will be able to observe about 1000 exoplanets depending on the details of the adopted survey strategy, thus confirming the feasibility of the main science objectives.Peer reviewedFinal Published versio
EarthFinder Probe Mission Concept Study: Characterizing nearby stellar exoplanet systems with Earth-mass analogs for future direct imaging
EarthFinder is a NASA Astrophysics Probe mission concept selected for study as input to the 2020 Astrophysics National Academies Decadal Survey. The EarthFinder concept is based on a dramatic shift in our understanding of how PRV measurements should be made. We propose a new paradigm which brings the high precision, high cadence domain of transit photometry as demonstrated by Kepler and TESS to the challenges of PRV measurements at the cm/s level. This new paradigm takes advantage of: 1) broad wavelength coverage from the UV to NIR which is only possible from space to minimize the effects of stellar activity; 2) extremely compact, highly stable, highly efficient spectrometers (R>150,000) which require the diffraction-limited imaging possible only from space over a broad wavelength range; 3) the revolution in laser-based wavelength standards to ensure cm/s precision over many years; 4) a high cadence observing program which minimizes sampling-induced period aliases; 5) exploiting the absolute flux stability from space for continuum normalization for unprecedented line-by-line analysis not possible from the ground; and 6) focusing on the bright stars which will be the targets of future imaging missions so that EarthFinder can use a ~1.5 m telescope
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