155 research outputs found
Introduction : the role of the lexicon in actionality
Actionality (also referred to by labels such as "lexical aspect" or "aktionsart") is the semantic dimension that encodes the constituent phases and boundaries of situations. Despite its central role in aspectual interpretation, careful language-specific descriptions and typological surveys of actional systems have been rare thus far. In this introduction, we describe the steps that lead to the compilation of the present special issue. We discuss several theoretical and methodological challenges that both field linguists and typologists face when investigating actional systems in the languages of the world and we point out some of the important insights to be gained from such endeavors. We then proceed to give an overview of the individual and varied contributions that make up this issue.Non peer reviewe
Inequality and ethics in paediatric HIV remission research : from Mississippi to South Africa and back
In 2013, physician-researchers announced that a baby in Mississippi had been ‘functionally cured’ of HIV [Persaud, D., Gay, H., Ziemniak, C. F., Chen, Y. H., Piatak, M., Chun, T.-W., … Luzuriaga, K. (2013b, March). Functional HIV cure after very early ART of an infected infant. Paper presented at the 20th conference on retroviruses and opportunistic infections, Atlanta, GA]. Though the child later developed a detectable viral load, the case remains unprecedented, and trials to build on the findings are planned [National Institute of Allergy and Infectious Diseases. (2014). ‘Mississippi baby’ now has detectable HIV, researchers find. Retrieved from http://www.niaid.nih.gov/news/newsreleases/2014/pages/mississippibabyhiv.aspx]. Whether addressing HIV ‘cure’ or ‘remission’, scrutiny of this case has focused largely on scientific questions, with only introductory attention to ethics. The social inequalities and gaps in care that made the discovery possible – and their ethical implications for paediatric HIV remission – have gone largely unexamined. This paper describes structural inequalities surrounding the ‘Mississippi baby’ case and a parallel case in South Africa, where proof-of-concept studies are in the early stages. We argue that an ethical programme of research into infant HIV remission ought to be ‘structurally competent’, and recommend that paediatric remission studies consider including a research component focused on social protection and barriers to care.http://www.tandfonline.com/loi/rgph202017-07-25hb2016Immunolog
Search for nearby Earth analogs I. 15 planet candidates found in PFS data
30 pages, 20 figures, 3 tables, accepted for publication in ApJSThe radial velocity (RV) method plays a major role in the discovery of nearby exoplanets. To efficiently find planet candidates from the data obtained in high-precision RV surveys, we apply a signal diagnostic framework to detect RV signals that are statistically significant, consistent in time, robust in the choice of noise models, and do not correlated with stellar activity. Based on the application of this approach to the survey data of the Planet Finder Spectrograph, we report 15 planet candidates located in 14 stellar systems. We find that the orbits of the planet candidates around HD 210193, 103949, 8326, and 71135 are consistent with temperate zones around these stars (where liquid water could exist on the surface). With periods of 7.76 and 15.14 days, respectively, the planet candidates around star HIP 54373 form a 1:2 resonance system. These discoveries demonstrate the feasibility of automated detection of exoplanets from large RV surveys, which may provide a complete sample of nearby Earth analogs.Peer reviewedFinal Accepted Versio
A Six-Planet System Around the Star HD 34445
We present a new precision radial velocity dataset that reveals a
multi-planet system orbiting the G0V star HD 34445. Our 18-year span consists
of 333 precision radial velocity observations, 56 of which were previously
published, and 277 which are new data from Keck Observatory, Magellan at Las
Campanas Observatory, and the Automated Planet Finder at Lick Observatory.
These data indicate the presence of six planet candidates in Keplerian motion
about the host star with periods of 1057, 215, 118, 49, 677, and 5700 days, and
minimum masses of 0.63, 0.17, 0.1, 0.05, 0.12 and 0.38 Jupiter masses
respectively. The HD 34445 planetary system, with its high degree of
multiplicity, its long orbital periods, and its induced stellar radial velocity
half-amplitudes in the range is fundamentally unlike either our own solar system (in which only
Jupiter and Saturn induce significant reflex velocities for the Sun), or the
Kepler multiple-transiting systems (which tend to have much more compact
orbital configurations)Comment: 10 pages, 11 figure
Ethics of HIV research in children
No abstract available.http://www.thelancet.com/infection2016-06-30hb201
Ethical Challenges in the Middle Tier of Covid-19 Vaccine Allocation: Guidance for Organizational Decision-Making
This supplement to The Hastings Center’s “Ethical Framework” aims to help structure time-sensitive discussion of significant, foreseeable ethical concerns in responding to Covid-19 and to support collaboration across institutions throughout pandemic response and recovery. It is designed for use by county health systems and by hospitals, community health centers, and other health care organizations responsible for patient care or preventive health, including vaccine education, vaccine distribution, and vaccination. This document aims to support formal and informal convening and policy work within the same geographic region, such as a municipality, county, metropolitan area, state, or multistate area, led by public health authorities, health care institutions, or other groups involved in vaccine allocation. The document’s scope is limited to the ethics of vaccine distribution within the United States; it does not address the ethics of international cooperation and sharing vaccines versus focusing solely on ensuring vaccine access in one’s own nation (“vaccine nationalism”).
The focus of this document is the middle tier of vaccine allocation and the ethical challenges arising in the U.S. in the first half of 2021. This focus reflects general consensus and ongoing implementation concerning highest-priority vaccination of two populations: frontline health care workers and residents of long-term care facilities (the groups constituting “Phase 1a
in recommendations from the Advisory Committee on Immunization Practices [ACIP]).The ethical justification for prioritizing these populations was their high risk of contracting the virus, of passing it to others at high risk of severe disease, and, in the case of long-term care residents, of dying of severe Covid-19. Additional justifications include the relatively small size of these initial cohorts, the relative ease of locating them and providing the vaccine, and the value of public trust created by witnessing health professionals receiving the vaccine. There is also broad consensus that vaccine allocation to the general public—people without major risk factors and who can reasonably protect themselves through masking and physical distancing—should occur only after the vaccination of groups at high risk of infection or at high risk of severe illness or death if infected. This document therefore does not address the final stages of vaccine distribution to lower-risk members of the public
The test case of HD26965: difficulties disentangling weak Doppler signals from stellar activity
We report the discovery of a radial velocity signal that can be interpreted
as a planetary-mass candidate orbiting the K dwarf HD26965, with an orbital
period of 42.3640.015 days, or alternatively, as the presence of residual,
uncorrected rotational activity in the data. Observations include data from
HIRES, PFS, CHIRON, and HARPS, where 1,111 measurements were made over 16
years. Our best solution for HD26965 is consistent with a super-Earth that
has a minimum mass of 6.920.79 M orbiting at a distance of
0.2150.008 AU from its host star. We have analyzed the correlation between
spectral activity indicators and the radial velocities from each instrument,
showing moderate correlations that we include in our model. From this analysis,
we recover a 38 day signal, which matches some literature values of the
stellar rotation period. However, from independent Mt. Wilson HK data for this
star, we find evidence for a significant 42 day signal after subtraction of
longer period magnetic cycles, casting doubt on the planetary hypothesis for
this period. Although our statistical model strongly suggests that the 42-day
signal is Doppler in origin, we conclude that the residual effects of stellar
rotation are difficult to fully model and remove from this dataset,
highlighting the difficulties to disentangle small planetary signals and
photospheric noise, particularly when the orbital periods are close to the
rotation period of the star. This study serves as an excellent test case for
future works that aim to detect small planets orbiting `Sun-like' stars using
radial velocity measurements.Comment: 16 pages, 10 figures, 13 tables, accepted for publication in A
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Vaccine Hesitancy Narratives
In this collection of narratives, the authors describe their own experiences with and reflections on healthcare worker vaccine hesitancy. The narratives explore each author’s engagement with different communities experiencing vaccine hesitancy, touching on reasons for hesitancy, proposed solutions, and legal aspects. Author’s names appear above their narratives
MagAO Imaging of Long-period Objects (MILO). I. A Benchmark M Dwarf Companion Exciting a Massive Planet around the Sun-like Star HD 7449
We present high-contrast Magellan adaptive optics (MagAO) images of HD 7449,
a Sun-like star with one planet and a long-term radial velocity (RV) trend. We
unambiguously detect the source of the long-term trend from 0.6-2.15 \microns
~at a separation of \about 0\fasec 54. We use the object's colors and spectral
energy distribution to show that it is most likely an M4-M5 dwarf (mass \about
0.1-0.2 \msun) at the same distance as the primary and is therefore likely
bound. We also present new RVs measured with the Magellan/MIKE and PFS
spectrometers and compile these with archival data from CORALIE and HARPS. We
use a new Markov chain Monte Carlo procedure to constrain both the mass ( \msun ~at 99 confidence) and semimajor axis (\about 18 AU) of the M
dwarf companion (HD 7449B). We also refine the parameters of the known massive
planet (HD 7449Ab), finding that its minimum mass is
\mj, its semimajor axis is AU, and its eccentricity is
. We use N-body simulations to constrain the eccentricity
of HD 7449B to 0.5. The M dwarf may be inducing Kozai oscillations
on the planet, explaining its high eccentricity. If this is the case and its
orbit was initially circular, the mass of the planet would need to be
1.5 \mj. This demonstrates that strong constraints on known planets
can be made using direct observations of otherwise undetectable long-period
companions.Comment: Corrected planet mass error (7.8 Mj --> 1.09 Mj, in agreement with
previous studies
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