4,530 research outputs found
Using Machine Learning to Improve Personalised Prediction: A Data-Driven Approach to Segment and Stratify Populations for Healthcare
Population Health Management typically relies on subjective decisions to segment and stratify populations. This study combines unsupervised clustering for segmentation and supervised classification, personalised to clusters, for stratification. An increase in cluster homogeneity, sensitivity and positive predictive value was observed compared to an unlinked approach. This analysis demonstrates the potential for a cluster-then-predict methodology to improve and personalise decisions in healthcare systems
The GTC exoplanet transit spectroscopy survey. VI. A spectrally-resolved Rayleigh scattering slope in GJ 3470b
Aims. As a sub-Uranus-mass low-density planet, GJ 3470b has been found to
show a flat featureless transmission spectrum in the infrared and a tentative
Rayleigh scattering slope in the optical. We conducted an optical transmission
spectroscopy project to assess the impacts of stellar activity and to determine
whether or not GJ 3470b hosts a hydrogen-rich gas envelop. Methods. We observed
three transits with the low-resolution OSIRIS spectrograph at the 10.4 m Gran
Telescopio Canarias, and one transit with the high-resolution UVES spectrograph
at the 8.2 m Very Large Telescope. Results. From the high-resolution data, we
find that the difference of the Ca II H+K lines in- and out-of-transit is only
0.67 +/- 0.22%, and determine a magnetic filling factor of about 10-15%. From
the low-resolution data, we present the first optical transmission spectrum in
the 435-755 nm band, which shows a slope consistent with Rayleigh scattering.
Conclusions. After exploring the potential impacts of stellar activity in our
observations, we confirm that Rayleigh scattering in an extended
hydrogen/helium atmosphere is currently the best explanation. Further
high-precision observations that simultaneously cover optical and infrared
bands are required to answer whether or not clouds and hazes exist at
high-altitude.Comment: 12 pages, 11 figures, accepted for publication in A&
Ar-40 to Ar-39 dating of pseudotachylites from the Witwatersrand basin, South Africa, with implications for the formation of the Vredefort Dome
The formation of the Vredefort Dome, a structure in excess of 100 km in diameter and located in the approximate center of the Witwatersrand basin, is still the subject of lively geological controversy. It is widely accepted that its formation seems to have taken place in a single sudden event, herein referred to as the Vredefort event, accompanied by the release of gigantic amounts of energy. It is debated, however, whether this central event was an internal one, i.e., a cryptoexplosion triggered by volcanic or tectonic processes, or the impact of an extraterrestrial body. The results of this debate are presented
A Summary of Oxidation-Reduction Potentials
A. ferric-ferrous electrode. B. mercuric-mercurous electrode. C. manganese dioxide electrodes
Measuring the effective complexity of cosmological models
We introduce a statistical measure of the effective model complexity, called
the Bayesian complexity. We demonstrate that the Bayesian complexity can be
used to assess how many effective parameters a set of data can support and that
it is a useful complement to the model likelihood (the evidence) in model
selection questions. We apply this approach to recent measurements of cosmic
microwave background anisotropies combined with the Hubble Space Telescope
measurement of the Hubble parameter. Using mildly non-informative priors, we
show how the 3-year WMAP data improves on the first-year data by being able to
measure both the spectral index and the reionization epoch at the same time. We
also find that a non-zero curvature is strongly disfavored. We conclude that
although current data could constrain at least seven effective parameters, only
six of them are required in a scheme based on the Lambda-CDM concordance
cosmology.Comment: 9 pages, 4 figures, revised version accepted for publication in PRD,
updated with WMAP3 result
Effects of long-term exposure to antimicrobial colistin sulfate (polymyxin E) over mixed cultures of nitrifiers and methanogens.
Thyroid hormones, blood plasma metabolites and haematological parameters in relationship to milk yield in dairy cows
To study their relationship to milk yield, the concentrations, in jugular venous blood, of thyroxine iodine (T4I), thyroxine (T4), 3,5,3'-tri-iodothyronine (T3), glucose, non-esterified fatty acids (NEFA), triglycerides, phospholipids, cholesterol, total protein, albumin, urea, haemoglobin and packed cell volume (PCV) have been measured in 36 cows (Simmental, Swiss Brown, Holstein and Simmental × Holstein) of different ages during a full lactation, pregnancy, dry period, parturition and 150 days of the ensuing lactation. Thyroid hormones and triglycerides were negatively, and total protein, globulin, cholesterol and phospholipids were positively, correlated with uncorrected or corrected milk yield during several periods of lactation, whereas glucose, NEFA, albumin, urea, haemoglobin and packed cell volume were not correlated with milk yield. The 10 animals with the highest milk yield (18·9 to 23·5 kg/day) exhibited significantly lower values of T4I, T4, T3 and glucose, significantly higher levels of total protein and globulin and tended to have higher levels of NEFA than the 10 cows with the lowest milk yield (10·9 to 14·3 kg/day) throughout or during certain periods of lactation, whereas concentrations of triglycerides, phospholipids, cholesterol, albumin, haemoglobin and PCV did not differ. Changes in T4I, T4, T3, glucose and total protein during lactation were also influenced by age, presumably associated with an increase in milk production with age. T3 was consistently lowest and cholesterol and phospholipids, during later stages of lactation, were highest in Holsteins, which had the highest milk yields of all breeds. Changes of blood parameters were mainly caused by shifts in energy and protein metabolism in association with level of milk productio
- …