51 research outputs found
An institutional ethnography of prevention and treatment services for substance use disorders in the Dominican Republic
The Dominican Republic is thought to have significant epidemics of illicit drug use but lacks surveillance and formal analyses of the policy context of drug prevention and treatment services. We conducted an institutional ethnography of 15 drug service organisations in Santo Domingo and Boca Chica, Dominican Republic, to explore barriers and resources for drug abuse prevention and treatment. Here, we present a typology of drug service organisations based on their services, methods, and approach. We then draw on interviews with representatives of drug service institutions to describe the primary barriers to drug treatment and prevention services for drug users. We conclude with a focus on the policy priorities that could improve the conditions of health care for marginalised drug users in the Dominican Republic
The effects of weather and climate change on dengue
There is much uncertainty about the future impact of climate change on vector-borne diseases. Such uncertainty reflects the difficulties in modelling the complex interactions between disease, climatic and socioeconomic determinants. We used a comprehensive panel dataset from Mexico covering 23 years of province-specific dengue reports across nine climatic regions to estimate the impact of weather on dengue, accounting for the effects of non-climatic factors
Knowledge, Motivations and Concerns about Participation in Breast Cancer Clinical Trials in Puerto Rico
Clinical trials (CT) in breast cancer have been crucial for new treatment discoveries. While participation in cancer CT is low, minorities are particularly underrepresented.This study aimed toidentify factors influencing the participation in CTs based on the experiences of Latina breast cancer survivors in Puerto Rico (PR), especially their CT knowledge, motivations, and concerns.Method:Focus groups (FG) were conducted by two social workers and the University of Puerto Rico/MD Anderson Community Health Educator. Participants were stratified into two subgroups: a) women with CT experience and b) those without CT experience. Seven FG were completed among breast cancer survivors (n=34) at two hospitals from the PR metropolitan area. Results: Our findings showed that participants expressed a basic knowledge and understanding of clinical trials. Motivations to participate included a desire to help others, non-monetary incentives to participation, self-benefits, readiness to participate based on the phases of illness, and enhanced relationships with the clinical trial recruitment team. Regardless of their previous experience with CTs, participants expressed concerns about participation including limited of knowledge about trial procedures and results, and lack of transportation, childcare, and support from family. Recommendations: The barriers and motivations identified for CT participation are modifiable and best targeted using a multidisciplinary approach.Social workers could play a potential role in participant recruitment and retention by clarifying research protocols to potential participants, as well as conducting CT. Our findings can help enhance capacity and training efforts for health professionals involved in CT recruitment and retention in culturally-relevant ways
The genomic basis of the plant island syndrome in Darwinâs giant daisies
The repeated, rapid and often pronounced patterns of evolutionary divergence observed in insular plants, or the âplant island syndromeâ, include changes in leaf phenotypes, growth, as well as the acquisition of a perennial lifestyle. Here, we sequence and describe the genome of the critically endangered, GalĂĄpagos-endemic species Scalesia atractyloides Arnot., obtaining a chromosome-resolved, 3.2-Gbp assembly containing 43,093 candidate gene models. Using a combination of fossil transposable elements, k-mer spectra analyses and orthologue assignment, we identify the two ancestral genomes, and date their divergence and the polyploidization event, concluding that the ancestor of all extant Scalesia species was an allotetraploid. There are a comparable number of genes and transposable elements across the two subgenomes, and while their synteny has been mostly conserved, we find multiple inversions that may have facilitated adaptation. We identify clear signatures of selection across genes associated with vascular development, growth, adaptation to salinity and flowering time, thus finding compelling evidence for a genomic basis of the island syndrome in one of Darwinâs giant daisies
Spitzer Reveals Evidence of Molecular Absorption in the Atmosphere of the Hot Neptune LTT 9779b
Non-rocky sub-Jovian exoplanets in high-irradiation environments are rare. LTT 9779b, also known as Transiting Exoplanet Survey Satellite (TESS) object of interest (TOI) 193.01, is one of the few such planets discovered to date, and the first example of an ultrahot Neptune. The planet's bulk density indicates that it has a substantial atmosphere, so to investigate its atmospheric composition and shed further light on its origin, we obtained Spitzer InfraRed Array Camera secondary eclipse observations of LTT 9779b at 3.6 and 4.5 Όm. We combined the Spitzer observations with a measurement of the secondary eclipse in the TESS bandpass. The resulting secondary eclipse spectrum strongly prefers a model that includes CO absorption over a blackbody spectrum, incidentally making LTT 9779b the first TESS exoplanet (and the first ultrahot Neptune) with evidence of a spectral feature in its atmosphere. We did not find evidence of a thermal inversion, at odds with expectations based on the atmospheres of similarly irradiated hot Jupiters. We also report a nominal dayside brightness temperature of 2305 ± 141 K (based on the 3.6 Όm secondary eclipse measurement), and we constrained the planet's orbital eccentricity to e < 0.01 at the 99.7% confidence level. Together with our analysis of LTT 9779b's thermal phase curves reported in a companion paper, our results set the stage for similar investigations of a larger sample of exoplanets discovered in the hot-Neptune desert, investigations that are key to uncovering the origin of this population
EPIC 201702477b : a transiting brown dwarf from K2 in a 41 day orbit
We report the discovery of EPIC 201702477b, a transiting brown dwarf in a long period (40.73691 ± 0.00037 day) and eccentric (e = 0.2281 ± 0.0026) orbit. This system was initially reported as a planetary candidate based on two transit events seen in K2 Campaign 1 photometry and later validated as an exoplanet candidate. We confirm the transit and refine the ephemeris with two subsequent ground-based detections of the transit using the Las Cumbres Observatory Global Telescope 1 m telescope network. We rule out any transit timing variations above the level of âŒ30 s. Using high precision radial velocity measurements from HARPS and SOPHIE we identify the transiting companion as a brown dwarf with a mass, radius, and bulk density of 66.9 ± 1.7 MJ, 0.757 ± 0.065 RJ, and 191 ± 51 g cm-3 respectively. EPIC 201702477b is the smallest radius brown dwarf yet discovered, with a mass just below the H-burning limit. It has the highest density of any planet, substellar mass object, or main-sequence star discovered so far. We find evidence in the set of known transiting brown dwarfs for two populations of objects - high mass brown dwarfs and low mass brown dwarfs. The higher-mass population have radii in very close agreement to theoretical models, and show a lower-mass limit around 60 MJ. This may be the signature of mass-dependent ejection of systems during the formation process.Publisher PDFPeer reviewe
TOI-954 B And K2-329 B: Short-Period Saturn-Mass Planets That Test Whether Irradiation Leads To Inflation
We report the discovery of two short-period Saturn-mass planets, one transiting the G subgiant TOI-954 (TIC 44792534, V = 10.343, T = 9.78) observed in TESS sectors 4 and 5 and one transiting the G dwarf K2-329 (EPIC 246193072, V = 12.70, K = 10.67) observed in K2 campaigns 12 and 19. We confirm and characterize these two planets with a variety of ground-based archival and follow-up observations, including photometry, reconnaissance spectroscopy, precise radial velocity, and high-resolution imaging. Combining all available data, we find that TOI-954 b has a radius of and a mass of MJ and is in a 3.68 day orbit, while K2-329 b has a radius of and a mass of MJ and is in a 12.46 day orbit. As TOI-954 b is 30 times more irradiated than K2-329 b but more or less the same size, these two planets provide an opportunity to test whether irradiation leads to inflation of Saturn-mass planets and contribute to future comparative studies that explore Saturn-mass planets at contrasting points in their lifetimes
A Remnant Planetary Core In The Hot-Neptune desert
The interiors of giant planets remain poorly understood. Even for the planets in the Solar System, difficulties in observation lead to large uncertainties in the properties of planetary cores. Exoplanets that have undergone rare evolutionary processes provide a route to understanding planetary interiors. Planets found in and near the typically barren hot-Neptune âdesertâ1,2 (a region in massâradius space that contains few planets) have proved to be particularly valuable in this regard. These planets include HD149026b3, which is thought to have an unusually massive core, and recent discoveries such as LTT9779b4 and NGTS-4b5, on which photoevaporation has removed a substantial part of their outer atmospheres. Here we report observations of the planet TOI-849b, which has a radius smaller than Neptuneâs but an anomalously large mass of 39.1+2.7â2.6 Earth masses and a density of 5.2+0.7â0.8 grams per cubic centimetre, similar to Earthâs. Interior-structure models suggest that any gaseous envelope of pure hydrogen and helium consists of no more than 3.9+0.8â0.9 per cent of the total planetary mass. The planet could have been a gas giant before undergoing extreme mass loss via thermal self-disruption or giant planet collisions, or it could have avoided substantial gas accretion, perhaps through gap opening or late formation6. Although photoevaporation rates cannot account for the mass loss required to reduce a Jupiter-like gas giant, they can remove a small (a few Earth masses) hydrogen and helium envelope on timescales of several billion years, implying that any remaining atmosphere on TOI-849b is likely to be enriched by water or other volatiles from the planetary interior. We conclude that TOI-849b is the remnant core of a giant planet
Latitude dictates plant diversity effects on instream decomposition
Running waters contribute substantially to global carbon fluxes through decomposition of terrestrial plant litter by aquatic microorganisms and detritivores. Diversity of this litter may influence instream decomposition globally in ways that are not yet understood. We investigated latitudinal differences in decomposition of litter mixtures of low and high functional diversity in 40 streams on 6 continents and spanning 113 degrees of latitude. Despite important variability in our dataset, we found latitudinal differences in the effect of litter functional diversity on decomposition, which we explained as evolutionary adaptations of litter-consuming detritivores to resource availability. Specifically, a balanced diet effect appears to operate at lower latitudes versus a resource concentration effect at higher latitudes. The latitudinal pattern indicates that loss of plant functional diversity will have different consequences on carbon fluxes across the globe, with greater repercussions likely at low latitudes
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