124 research outputs found

    Predicting the environmental suitability for onchocerciasis in Africa as an aid to elimination planning

    Get PDF
    Recent evidence suggests that, in some foci, elimination of onchocerciasis from Africa may be feasible with mass drug administration (MDA) of ivermectin. To achieve continental elimination of transmission, mapping surveys will need to be conducted across all implementation units (IUs) for which endemicity status is currently unknown. Using boosted regression tree models with optimised hyperparameter selection, we estimated environmental suitability for onchocerciasis at the 5 × 5-km resolution across Africa. In order to classify IUs that include locations that are environmentally suitable, we used receiver operating characteristic (ROC) analysis to identify an optimal threshold for suitability concordant with locations where onchocerciasis has been previously detected. This threshold value was then used to classify IUs (more suitable or less suitable) based on the location within the IU with the largest mean prediction. Mean estimates of environmental suitability suggest large areas across West and Central Africa, as well as focal areas of East Africa, are suitable for onchocerciasis transmission, consistent with the presence of current control and elimination of transmission efforts. The ROC analysis identified a mean environmental suitability index of 0·71 as a threshold to classify based on the location with the largest mean prediction within the IU. Of the IUs considered for mapping surveys, 50·2% exceed this threshold for suitability in at least one 5 × 5-km location. The formidable scale of data collection required to map onchocerciasis endemicity across the African continent presents an opportunity to use spatial data to identify areas likely to be suitable for onchocerciasis transmission. National onchocerciasis elimination programmes may wish to consider prioritising these IUs for mapping surveys as human resources, laboratory capacity, and programmatic schedules may constrain survey implementation, and possibly delaying MDA initiation in areas that would ultimately qualify

    Clinical relevance assessment of animal preclinical research (RAA) tool: development and explanation.

    Get PDF
    Only a small proportion of preclinical research (research performed in animal models prior to clinical trials in humans) translates into clinical benefit in humans. Possible reasons for the lack of translation of the results observed in preclinical research into human clinical benefit include the design, conduct, and reporting of preclinical studies. There is currently no formal domain-based assessment of the clinical relevance of preclinical research. To address this issue, we have developed a tool for the assessment of the clinical relevance of preclinical studies, with the intention of assessing the likelihood that therapeutic preclinical findings can be translated into improvement in the management of human diseases. We searched the EQUATOR network for guidelines that describe the design, conduct, and reporting of preclinical research. We searched the references of these guidelines to identify further relevant publications and developed a set of domains and signalling questions. We then conducted a modified Delphi-consensus to refine and develop the tool. The Delphi panel members included specialists in evidence-based (preclinical) medicine specialists, methodologists, preclinical animal researchers, a veterinarian, and clinical researchers. A total of 20 Delphi-panel members completed the first round and 17 members from five countries completed all three rounds. This tool has eight domains (construct validity, external validity, risk of bias, experimental design and data analysis plan, reproducibility and replicability of methods and results in the same model, research integrity, and research transparency) and a total of 28 signalling questions and provides a framework for researchers, journal editors, grant funders, and regulatory authorities to assess the potential clinical relevance of preclinical animal research. We have developed a tool to assess the clinical relevance of preclinical studies. This tool is currently being piloted

    True Metabolizable Energy of Two Southern Aquatic Plants

    Get PDF
    In order to improve the accuracy of energetic models used to set habitat objectives, estimates of energy availability and metabolizability for a variety of aquatic plants are needed. While true metabolizable energy (TME) values are available for many species of moist-soil seeds, hard mast, agricultural grains, and invertebrates, few TME values exist in the published literature for submersed aquatic vegetation (SAV), despite SAV being a significant food item of many dabbling and diving duck species. Moreover, neither of the two plant species previous analyzed (i.e., shoalgrass [Halodule wrightii], Ballard et al. 2004; widgeon grass [Ruppia maritime], Coluccy et al. 2015) have values near means of other natural foods (Kaminski et al. 2003). Thus, there may exist significant energetic tradeoffs in managing wetland for SAV as opposed to moist-soil or agricultural crops. Moreover, TME values for both native and non-native species such as wild celery (Vallisneria americana) and hydrilla (Hydrilla verticillata) have not been previously published and are needed to assess the value for ducks and the 3 energetic tradeoffs of their control. Orth et al. (2017) suggested that scientists critically evaluate the ecosystem services provided by invasive vs native species before undertaking substantial efforts to manage an invasive. Therefore, we developed the following objectives aimed at estimating the TME of hydrilla for two waterfowl species and providing a comparison native vegetation for ring-necked ducks (Aythya collaris). Objectives 1)Estimate true metabolizable energy of hydrilla shoots and tubers for mallards (Anas platyrhynchos), and 2)Estimate true metabolizable energy of hydrilla and wild celery shoots for ring-necked ducks.Aquatic Ecosystems Restoration FoundationFlorida Fish and Wildlife Conservation Commissionunpublishednot peer reviewedOpe

    TOI-733 b -- a planet in the small-planet radius valley orbiting a Sun-like star

    Get PDF
    We report the discovery of a hot (TeqT_{\rm eq} ≈\approx 1055 K) planet in the small planet radius valley transiting the Sun-like star TOI-733, as part of the KESPRINT follow-up program of TESS planets carried out with the HARPS spectrograph. TESS photometry from sectors 9 and 36 yields an orbital period of PorbP_{\rm orb} = 4.884765−2.4e−5+1.9e−54.884765 _{ - 2.4e-5 } ^ { + 1.9e-5 } days and a radius of RpR_{\mathrm{p}} = 1.992−0.090+0.0851.992 _{ - 0.090 } ^ { + 0.085 } R⊕R_{\oplus}. Multi-dimensional Gaussian process modelling of the radial velocity measurements from HARPS and activity indicators, gives a semi-amplitude of KK = 2.23±0.262.23 \pm 0.26 m s−1^{-1}, translating into a planet mass of MpM_{\mathrm{p}} = 5.72−0.68+0.705.72 _{ - 0.68 } ^ { + 0.70 } M⊕M_{\oplus}. These parameters imply that the planet is of moderate density (ρp\rho_\mathrm{p} = 3.98−0.66+0.773.98 _{ - 0.66 } ^ { + 0.77 } g cm−3^{-3}) and place it in the transition region between rocky and volatile-rich planets with H/He-dominated envelopes on the mass-radius diagram. Combining these with stellar parameters and abundances, we calculate planet interior and atmosphere models, which in turn suggest that TOI-733 b has a volatile-enriched, most likely secondary outer envelope, and may represent a highly irradiated ocean world - one of only a few such planets around G-type stars that are well-characterised.Comment: Accepted for publication in A&

    Home Range and Ranging Behaviour of Bornean Elephant (Elephas maximus borneensis) Females

    Get PDF
    BACKGROUND: Home range is defined as the extent and location of the area covered annually by a wild animal in its natural habitat. Studies of African and Indian elephants in landscapes of largely open habitats have indicated that the sizes of the home range are determined not only by the food supplies and seasonal changes, but also by numerous other factors including availability of water sources, habitat loss and the existence of man-made barriers. The home range size for the Bornean elephant had never been investigated before. METHODOLOGY/PRINCIPAL FINDINGS: The first satellite tracking program to investigate the movement of wild Bornean elephants in Sabah was initiated in 2005. Five adult female elephants were immobilized and neck collars were fitted with tracking devices. The sizes of their home range and movement patterns were determined using location data gathered from a satellite tracking system and analyzed by using the Minimum Convex Polygon and Harmonic Mean methods. Home range size was estimated to be 250 to 400 km(2) in a non-fragmented forest and 600 km(2) in a fragmented forest. The ranging behavior was influenced by the size of the natural forest habitat and the availability of permanent water sources. The movement pattern was influenced by human disturbance and the need to move from one feeding site to another. CONCLUSIONS/SIGNIFICANCE: Home range and movement rate were influenced by the degree of habitat fragmentation. Once habitat was cleared or converted, the availability of food plants and water sources were reduced, forcing the elephants to travel to adjacent forest areas. Therefore movement rate in fragmented forest was higher than in the non-fragmented forest. Finally, in fragmented habitat human and elephant conflict occurrences were likely to be higher, due to increased movement bringing elephants into contact more often with humans

    HD 20329b: An ultra-short-period planet around a solar-type star found by TESS

    Get PDF
    We used TESS light curves and HARPS-N spectrograph radial velocity measurements to establish the physical properties of the transiting exoplanet candidate found around the star HD 20329 (TOI-4524). We performed a joint fit of the light curves and radial velocity time series to measure the mass, radius, and orbital parameters of the candidate. We confirm and characterize HD 20329b, an ultra-short-period (USP) planet transiting a solar-type star. The host star (HD 20329, V=8.74V = 8.74 mag, J=7.5J = 7.5 mag) is characterized by its G5 spectral type with M⋆=0.90±0.05\mathrm{M}_\star= 0.90 \pm 0.05 M⊙_\odot, R⋆=1.13±0.02\mathrm{R}_\star = 1.13 \pm 0.02 R⊙_\odot, and Teff=5596±50\mathrm{T}_{\mathrm{eff}} = 5596 \pm 50 K; it is located at a distance d=63.68±0.29d= 63.68 \pm 0.29 pc. By jointly fitting the available TESS transit light curves and follow-up radial velocity measurements, we find an orbital period of 0.9261±(0.5×10−4)0.9261 \pm (0.5\times 10^{-4}) days, a planetary radius of 1.72±0.071.72 \pm 0.07 R⊕\mathrm{R}_\oplus, and a mass of 7.42±1.097.42 \pm 1.09 M⊕\mathrm{M}_\oplus, implying a mean density of ρp=8.06±1.53\rho_\mathrm{p} = 8.06 \pm 1.53 g cm−3^{-3}. HD 20329b joins the ∌\sim30 currently known USP planets with radius and Doppler mass measurements.Comment: Accepted for publication in A&A, 26 page

    Company for the ultra-high density, ultra-short period sub-Earth GJ 367 b: discovery of two additional low-mass planets at 11.5 and 34 days

    Get PDF
    GJ 367 is a bright (V ≈\approx 10.2) M1 V star that has been recently found to host a transiting ultra-short period sub-Earth on a 7.7 hr orbit. With the aim of improving the planetary mass and radius and unveiling the inner architecture of the system, we performed an intensive radial velocity follow-up campaign with the HARPS spectrograph -- collecting 371 high-precision measurements over a baseline of nearly 3 years -- and combined our Doppler measurements with new TESS observations from sectors 35 and 36. We found that GJ 367 b has a mass of MbM_\mathrm{b} = 0.633 ±\pm 0.050 M⊕_{\oplus} and a radius of RbR_\mathrm{b} = 0.699 ±\pm 0.024 R⊕_{\oplus}, corresponding to precisions of 8% and 3.4%, respectively. This implies a planetary bulk density of ρb\rho_\mathrm{b} = 10.2 ±\pm 1.3 g cm−3^{-3}, i.e., 85% higher than Earth's density. We revealed the presence of two additional non transiting low-mass companions with orbital periods of ∌\sim11.5 and 34 days and minimum masses of Mcsin⁥icM_\mathrm{c}\sin{i_\mathrm{c}} = 4.13 ±\pm 0.36 M⊕_{\oplus} and Mdsin⁥idM_\mathrm{d}\sin{i_\mathrm{d}} = 6.03 ±\pm 0.49 M⊕_{\oplus}, respectively, which lie close to the 3:1 mean motion commensurability. GJ 367 b joins the small class of high-density planets, namely the class of super-Mercuries, being the densest ultra-short period small planet known to date. Thanks to our precise mass and radius estimates, we explored the potential internal composition and structure of GJ 367 b, and found that it is expected to have an iron core with a mass fraction of 0.91−0.23+0.07^{+0.07}_{-0.23}. How this iron core is formed and how such a high density is reached is still not clear, and we discuss the possible pathways of formation of such a small ultra-dense planet.Comment: 28 pages, 11 figures. Accepted for publication in ApJ

    Credibility in Policy Expertise: The Function of Boundaries Between Research and Policy

    Get PDF
    As science becomes an increasingly crucial resource for addressing complex challenges in society, extensive demands are placed upon the researchers who produce it. Creating valuable expert knowledge that intervenes in policy or practice requires knowledge brokers to facilitate interactions at the boundary between research and policy. Yet, existing research lacks a compelling account of the ways in which brokerage is performed to gain credibility. Drawing on mixed-method analysis of twelve policy research settings, I outline a novel set of strategies for attaining symbolic power, whereby policy experts position themselves and others via conceptual distances drawn between the ‘world of ideas’ and the ‘world of policy and practice’. Disciplinary distance works to situate research as either disciplinary or undisciplinary, epistemic distance creates a boundary between complex specialist research and direct digestible outputs, temporal distance represents the separation of slow rigorous research and agile responsive analysis, and economic distance situates research as either pure and intrinsic or marketable and fundable. I develop a theoretical account that unpacks the boundaries between research communities and shows how these boundaries permit policy research actors to achieve various strategic aims.ESRC Future Research Leaders ES/N016319/1 Commonwealth Scholarship Commissio

    TOI-2196 b : Rare planet in the hot Neptune desert transiting a G-type star

    Get PDF
    Funding: C.M.P., M.F., I.G., and J.K. gratefully acknowledge the support of the Swedish National Space Agency (DNR 65/19, 174/18, 177/19, 2020-00104). L.M.S and D.G. gratefully acknowledge financial support from the CRT foundation under Grant No. 2018.2323 “Gaseous or rocky? Unveiling the nature of small worlds”. P.K. acknowledges support from grant LTT-20015. E.G. acknowledge the support of the ThĂŒringer Ministerium fĂŒr Wirtschaft, Wissenschaft und Digitale Gesellschaft. J.S.J. gratefully acknowledges support by FONDECYT grant 1201371 and from the ANID BASAL projects ACE210002 and FB210003. H.J.D. acknowledges support from the Spanish Research Agency of the Ministry of Science and Innovation (AEI-MICINN) under grant PID2019-107061GBC66, DOI: 10.13039/501100011033. D.D. acknowledges support from the TESS Guest Investigator Program grants 80NSSC21K0108 and 80NSSC22K0185. M.E. acknowledges the support of the DFG priority program SPP 1992 "Exploring the Diversity of Extrasolar Planets" (HA 3279/12-1). K.W.F.L. was supported by Deutsche Forschungsgemeinschaft grants RA714/14-1 within the DFG Schwerpunkt SPP 1992, Exploring the Diversity of Extrasolar Planets. N.N. acknowledges support from JSPS KAKENHI Grant Number JP18H05439, JST CREST Grant Number JPMJCR1761. M.S.I.P. is funded by NSF.The hot Neptune desert is a region hosting a small number of short-period Neptunes in the radius-instellation diagram. Highly irradiated planets are usually either small (R â‰Č 2 R⊕) and rocky or they are gas giants with radii of ≳1 RJ. Here, we report on the intermediate-sized planet TOI-2196 b (TIC 372172128.01) on a 1.2 day orbit around a G-type star (V = 12.0, [Fe/H] = 0.14 dex) discovered by the Transiting Exoplanet Survey Satellite in sector 27. We collected 41 radial velocity measurements with the HARPS spectrograph to confirm the planetary nature of the transit signal and to determine the mass. The radius of TOI-2196 b is 3.51 ± 0.15 R⊕, which, combined with the mass of 26.0 ± 1.3 M⊕, results in a bulk density of 3.31−0.43+0.51 g cm−3. Hence, the radius implies that this planet is a sub-Neptune, although the density is twice than that of Neptune. A significant trend in the HARPS radial velocity measurements points to the presence of a distant companion with a lower limit on the period and mass of 220 days and 0.65 MJ, respectively, assuming zero eccentricity. The short period of planet b implies a high equilibrium temperature of 1860 ± 20 K, for zero albedo and isotropic emission. This places the planet in the hot Neptune desert, joining a group of very few planets in this parameter space discovered in recent years. These planets suggest that the hot Neptune desert may be divided in two parts for planets with equilibrium temperatures of ≳1800 K: a hot sub-Neptune desert devoid of planets with radii of ≈ 1.8−3 R⊕ and a sub-Jovian desert for radii of ≈5−12 R⊕. More planets in this parameter space are needed to further investigate this finding. Planetary interior structure models of TOI-2196 b are consistent with a H/He atmosphere mass fraction between 0.4% and 3%, with a mean value of 0.7% on top of a rocky interior. We estimated the amount of mass this planet might have lost at a young age and we find that while the mass loss could have been significant, the planet had not changed in terms of character: it was born as a small volatile-rich planet and it remains one at present.Publisher PDFPeer reviewe
    • 

    corecore