Clustering clinical departments for wards to achieve a prespecified blocking probability

When the number of available beds in a hospital is limited and fixed, it can be beneficial to cluster several clinical departments such that the probability of not being able to admit a patient is acceptably small. The clusters are then assigned to the available wards such that enough beds are available to guarantee a blocking probability below a prespecified value. We first give an exact formulation of the problem to be able to achieve optimal solutions. To reduce computation times, we also introduce two heuristic solution methods. The first heuristic is similar to the exact solution method, however, the number of beds needed is approximated by a linear function. The second heuristic uses a local search approach to determine the assignment of clinical departments to clusters and a restricted version of the exact solution method to determine the assignment of clusters to wards

Kepler-210: An active star with at least two planets

We report the detection and characterization of two short-period, Neptune-sized planets around the active host star Kepler-210. The host star's parameters derived from those planets are (a) mutually inconsistent and (b) do not conform to the expected host star parameters. We furthermore report the detection of transit timing variations (TTVs) in the O-C diagrams for both planets. We explore various scenarios that explain and resolve those discrepancies. A simple scenario consistent with all data appears to be one that attributes substantial eccentricities to the inner short-period planets and that interprets the TTVs as due to the action of another, somewhat longer period planet. To substantiate our suggestions, we present the results of N-body simulations that modeled the TTVs and that checked the stability of the Kepler-210 system.Comment: 8 pages, 8 Encapsulated Postscript figure

МЕТОДИЧНІ ВКАЗІВКИ З ПРАКТИЧНОГО КУРСУ АНГЛІЙСЬКОЇ МОВИ (вступний фонетичний курс) для студентів 1 курсу (напрям підготовки 0305 “Філологія”, спеціальність 6.030500 “Переклад”)

МЕТОДИЧНІ ВКАЗІВКИ З ПРАКТИЧНОГО КУРСУ АНГЛІЙСЬКОЇ МОВИ (вступний фонетичний курс) для студентів 1 курсу (напрям підготовки 0305 “Філологія”, спеціальність 6.030500 “Переклад”)МЕТОДИЧНІ ВКАЗІВКИ З ПРАКТИЧНОГО КУРСУ АНГЛІЙСЬКОЇ МОВИ (вступний фонетичний курс) для студентів 1 курсу (напрям підготовки 0305 “Філологія”, спеціальність 6.030500 “Переклад”

Long Range Magnetic Order and the Darwin Lagrangian

We simulate a finite system of $N$ confined electrons with inclusion of the Darwin magnetic interaction in two- and three-dimensions. The lowest energy states are located using the steepest descent quenching adapted for velocity dependent potentials. Below a critical density the ground state is a static Wigner lattice. For supercritical density the ground state has a non-zero kinetic energy. The critical density decreases with $N$ for exponential confinement but not for harmonic confinement. The lowest energy state also depends on the confinement and dimension: an antiferromagnetic cluster forms for harmonic confinement in two dimensions.Comment: 5 figure

Improve OR-schedule to reduce number of required beds

After surgery most of the surgical patients have to be admitted in a ward in the hospital. Due to financial reasons and an decreasing number of available nurses in the Netherlands over the years, it is important to reduce the bed usage as much as possible. One possible way to achieve this is to create an operating room (OR) schedule that spreads the usage of beds nicely over time, and thereby minimizes the number of required beds. An OR-schedule is given by an assignment of OR-blocks to specific days in the planning horizon and has to fulfill several resource constraints. Due to the stochastic nature of the length of stay of patients, the analytic calculation of the number of required beds for a given OR-schedule is a complex task involving the convolution of discrete distributions. In this paper, two approaches to deal with this complexity are presented. First, a heuristic approach based on local search is given, which takes into account the detailed formulation of the objective. A second approach reduces the complexity by simplifying the objective function. This allows modeling and solving the resulting problem as an ILP. Both approaches are tested on data provided by Hagaziekenhuis in the Netherlands. Furthermore, several what-if scenarios are evaluated. The computational results show that the approach that uses the simplified objective function provides better solutions to the original problem. By using this approach, the number of required beds for the considered instance of HagaZiekenhuis can be reduced by almost 20%

Low albedos of hot to ultra-hot Jupiters in the optical to near-infrared transition regime

The depth of a secondary eclipse contains information of both the thermally emitted light component of a hot Jupiter and the reflected light component. If the dayside atmosphere of the planet is assumed to be isothermal, it is possible to disentangle both. In this work, we analyze 11 eclipse light curves of the hot Jupiter HAT-P-32b obtained at 0.89 $\mu$m in the z' band. We obtain a null detection for the eclipse depth with state-of-the-art precision, -0.01 +- 0.10 ppt. We confirm previous studies showing that a non-inverted atmosphere model is in disagreement to the measured emission spectrum of HAT-P-32b. We derive an upper limit on the reflected light component, and thus, on the planetary geometric albedo $A_g$. The 97.5%-confidence upper limit is $A_g$ < 0.2. This is the first albedo constraint for HAT-P-32b, and the first z' band albedo value for any exoplanet. It disfavors the influence of large-sized silicate condensates on the planetary day side. We inferred z' band geometric albedo limits from published eclipse measurements also for the ultra-hot Jupiters WASP-12b, WASP-19b, WASP-103b, and WASP-121b, applying the same method. These values consistently point to a low reflectivity in the optical to near-infrared transition regime for hot to ultra-hot Jupiters.Comment: accepted for publication in A&

Quantitative assessment of prefrontal cortex in humans relative to nonhuman primates

Significance A longstanding controversy in neuroscience pertains to differences in human prefrontal cortex (PFC) compared with other primate species; specifically, is human PFC disproportionately large? Distinctively human behavioral capacities related to higher cognition and affect presumably arose from evolutionary modifications since humans and great apes diverged from a common ancestor about 6–8 Mya. Accurate determination of regional differences in the amount of cortical gray and subcortical white matter content in humans, great apes, and Old World monkeys can further our understanding of the link between structure and function of the human brain. Using tissue volume analyses, we show a disproportionately large amount of gray and white matter corresponding to PFC in humans compared with nonhuman primates.</jats:p

First Light of Engineered Diffusers at the Nordic Optical Telescope Reveal Time Variability in the Optical Eclipse Depth of WASP-12b

We present the characterization of two engineered diffusers mounted on the 2.5 meter Nordic Optical Telescope, located at Roque de Los Muchachos, Spain. To assess the reliability and the efficiency of the diffusers, we carried out several test observations of two photometric standard stars, along with observations of one primary transit observation of TrES-3b in the red (R-band), one of CoRoT-1b in the blue (B-band), and three secondary eclipses of WASP-12b in V-band. The achieved photometric precision is in all cases within the sub-millimagnitude level for exposures between 25 and 180 seconds. Along a detailed analysis of the functionality of the diffusers, we add a new transit depth measurement in the blue (B-band) to the already observed transmission spectrum of CoRoT-1b, disfavouring a Rayleigh slope. We also report variability of the eclipse depth of WASP-12b in the V-band. For the WASP-12b secondary eclipses, we observe a secondary-depth deviation of about 5-sigma, and a difference of 6-sigma and 2.5-sigma when compared to the values reported by other authors in similar wavelength range determined from Hubble Space Telescope data. We further speculate about the potential physical processes or causes responsible for this observed variabilityComment: 11 pages, 9 figure

Transmission spectroscopy of the inflated exo-Saturn HAT-P-19b

We observed the Saturn-mass and Jupiter-sized exoplanet HAT-P-19b to refine its transit parameters and ephemeris as well as to shed first light on its transmission spectrum. We monitored the host star over one year to quantify its flux variability and to correct the transmission spectrum for a slope caused by starspots. A transit of HAT-P-19b was observed spectroscopically with OSIRIS at the Gran Telescopio Canarias in January 2012. The spectra of the target and the comparison star covered the wavelength range from 5600 to 7600 AA. One high-precision differential light curve was created by integrating the entire spectral flux. This white-light curve was used to derive absolute transit parameters. Furthermore, a set of light curves over wavelength was formed by a flux integration in 41 wavelength channels of 50 AA width. We analyzed these spectral light curves for chromatic variations of transit depth. The transit fit of the combined white-light curve yields a refined value of the planet-to-star radius ratio of 0.1390 pm 0.0012 and an inclination of 88.89 pm 0.32 degrees. After a re-analysis of published data, we refine the orbital period to 4.0087844 pm 0.0000015 days. We obtain a flat transmission spectrum without significant additional absorption at any wavelength or any slope. However, our accuracy is not sufficient to significantly rule out the presence of a pressure-broadened sodium feature. Our photometric monitoring campaign allowed for an estimate of the stellar rotation period of 35.5 pm 2.5 days and an improved age estimate of 5.5^+1.8_-1.3 Gyr by gyrochronology.Comment: 14 pages, 9 figures, Accepted for publication in A&