Comparison of Gaia and asteroseismic distances

Asteroseismology provides fundamental properties (mass, radius and effective temperature) of solar-like oscillating stars using so-called scaling relations. These properties allow the computation of the asteroseismic distance of stars. We compare the asteroseismic distances with the recently released Gaia distances for 74 stars studied in Y{\i}ld{\i}z et al. There is a very good agreement between these two distances; for 64 of these stars, the difference is less than 10 per cent. However, a systematic difference is seen if we use the effective temperature obtained by spectroscopic methods; the Gaia distances are about 5 per cent greater than the asteroseismic distances.Comment: 4 pages, 4 figures, accepted by MNRA

Nash bargaining in ordinal environments

We analyze the implications of Nash’s (1950) axioms in ordinal bargaining environments; there, the scale invariance axiom needs to be strenghtened to take into account all order-preserving transformations of the agents’ utilities. This axiom, called ordinal invariance, is a very demanding one. For two-agents, it is violated by every strongly individually rational bargaining rule. In general, no ordinally invariant bargaining rule satisfies the other three axioms of Nash. Parallel to Roth (1977), we introduce a weaker independence of irrelevant alternatives axiom that we argue is better suited for ordinally invariant bargaining rules. We show that the three-agent Shapley-Shubik bargaining rule uniquely satisfies ordinal invariance, Pareto optimality, symmetry, and this weaker independence of irrelevant alternatives axiom. We also analyze the implications of other independence axioms

Exploiting metric structure for efficient private query release

We consider the problem of privately answering queries defined on databases which are collections of points belonging to some metric space. We give simple, computationally efficient algorithms for answering distance queries defined over an arbitrary metric. Distance queries are specified by points in the metric space, and ask for the average distance from the query point to the points contained in the database, according to the specified metric. Our algorithms run efficiently in the database size and the dimension of the space, and operate in both the online query release setting, and the offline setting in which they must in polynomial time generate a fixed data structure which can answer all queries of interest. This represents one of the first subclasses of linear queries for which efficient algorithms are known for the private query release problem, circumventing known hardness results for generic linear queries. Copyright © 2014 by the Society for Industrial and Applied Mathematics.postprin

A novel approach to modelling and simulating the contact behaviour between a human hand model and a deformable object

A deeper understanding of biomechanical behaviour of human hands becomes fundamental for any human hand-operated Q2 activities. The integration of biomechanical knowledge of human hands into product design process starts to play an increasingly important role in developing an ergonomic product-to-user interface for products and systems requiring high level of comfortable and responsive interactions. Generation of such precise and dynamic models can provide scientific evaluation tools to support product and system development through simulation. This type of support is urgently required in many applications such as hand skill training for surgical operations, ergonomic study of a product or system developed and so forth. The aim of this work is to study the contact behaviour between the operators’ hand and a hand-held tool or other similar contacts, by developing a novel and precise nonlinear 3D finite element model of the hand and by investigating the contact behaviour through simulation. The contact behaviour is externalised by solving the problem using the bi-potential method. The human body’s biomechanical characteristics, such as hand deformity and structural behaviour, have been fully modelled by implementing anisotropic hyperelastic laws. A case study is given to illustrate the effectiveness of the approac

Atmospheric ozone retrieval using radiance measurements from the Chappuis and Hartley-Huggins absorption bands

The monitoring of global ozone in the atmosphere is a necessary prerequisite to understanding atmospheric chemistry and managing atmospheric constituents. Satellite systems have been developed to measure ozone and other constituents accurately on a global basis. However, within this area there is considerable room for advancement in the techniques used to measure ozone from a satellite platform.The Canadian instrument OSIRIS onboard the Swedish-led satellite Odin contains an optical spectrograph that is used for measuring limb radiance in the atmosphere. There are various proven techniques to convert limb radiance data into ozone density profiles. This work presents a new technique that combines radiance data from both the Chappuis and Hartley-Huggins bands to retrieve ozone density. The new technique extends the current upper limit of Chappuis-only retrievals from 40 km to 60 km.The major portion of this work describes the implementation of this new technique. Briefly, a Multiplicative Algebraic Reconstructive Technique, together with the SaskTRAN radiative transfer model, is used to invert the limb radiance data into ozone density profiles.An overview of the resulting ozone density profiles is presented together with comparisons against other ozone products as a first order verification of the results.This work will be used to produce a new ozone data set from the OSIRIS limb radiance data consisting of ozone density profiles that are valid to 60 km

Tree of Life Synagogue Shooting in Pittsburgh: Preparedness, Prehospital Care, and Lessons Learned

On Saturday, October 27, 2018, a man with anti-Semitic motivations entered Tree of Life synagogue in the Squirrel Hill section of Pittsburgh, Pennsylvania; he had an AR-15 semi-automatic rifle and three handguns, opening fire upon worshippers. Eventually 11 civilians died at the scene and eight people sustained non-fatal injuries, including five police officers. Each person injured but alive at the scene received care at one of three local level-one trauma centers.  The injured had wounds often seen in war-settings, with the signature of high velocity weaponry.  We describe the scene response, specific elements of our hospital plans, the overall out-of-hospital preparedness in Pittsburgh, and the lessons learned

Fairness Incentives for Myopic Agents

We consider settings in which we wish to incentivize myopic agents (such as Airbnb landlords, who may emphasize short-term profits and property safety) to treat arriving clients fairly, in order to prevent overall discrimination against individuals or groups. We model such settings in both classical and contextual bandit models in which the myopic agents maximize rewards according to current empirical averages, but are also amenable to exogenous payments that may cause them to alter their choices. Our notion of fairness asks that more qualified individuals are never (probabilistically) preferred over less qualified ones [Joseph et al]. We investigate whether it is possible to design inexpensive {subsidy} or payment schemes for a principal to motivate myopic agents to play fairly in all or almost all rounds. When the principal has full information about the state of the myopic agents, we show it is possible to induce fair play on every round with a subsidy scheme of total cost $o(T)$ (for the classic setting with $k$ arms, $\tilde{O}(\sqrt{k^3T})$, and for the $d$-dimensional linear contextual setting $\tilde{O}(d\sqrt{k^3 T})$). If the principal has much more limited information (as might often be the case for an external regulator or watchdog), and only observes the number of rounds in which members from each of the $k$ groups were selected, but not the empirical estimates maintained by the myopic agent, the design of such a scheme becomes more complex. We show both positive and negative results in the classic and linear bandit settings by upper and lower bounding the cost of fair subsidy schemes

Magnetic-field induced resistivity minimum with in-plane linear magnetoresistance of the Fermi liquid in SrTiO3-x single crystals

We report novel magnetotransport properties of the low temperature Fermi liquid in SrTiO3-x single crystals. The classical limit dominates the magnetotransport properties for a magnetic field perpendicular to the sample surface and consequently a magnetic-field induced resistivity minimum emerges. While for the field applied in plane and normal to the current, the linear magnetoresistance (MR) starting from small fields (< 0.5 T) appears. The large anisotropy in the transverse MRs reveals the strong surface interlayer scattering due to the large gradient of oxygen vacancy concentration from the surface to the interior of SrTiO3-x single crystals. Moreover, the linear MR in our case was likely due to the inhomogeneity of oxygen vacancies and oxygen vacancy clusters, which could provide experimental evidences for the unusual quantum linear MR proposed by Abrikosov [A. A. Abrikosov, Phys. Rev. B 58, 2788 (1998)].Comment: 5 pages, 4 figure

Exploration des séries chronologiques d’analyse de la qualité des eaux de surface dans le bassin de la Tafna (Algérie)

La qualité des eaux de surface est sujette à de nombreuses fluctuations et par conséquence les gestionnaires sont souvent confrontés à des pics de pollution problématiques. À cet effet, nous présentons dans cette étude les résultats d’une exploration des séries d’analyses de la qualité des eaux de surface dans le bassin de la Tafna (Algérie). Nous avons retenu trois descripteurs de la qualité des eaux; la matière en suspension (MES), la conductivité et la demande chimique en oxygène (DCO). On dispose pour cette étude de séries de prélèvements instantanés d’une fréquence au moins mensuelle, couvrant une période de sept ans (avril 1995-mars 2002). Les stations de prélèvements choisies se situent sur les principaux cours d’eau du bassin de la Tafna (Mouillah, Isser et Tafna) de manière à couvrir l’ensemble du bassin versant.Afin d’aboutir à des conclusions exploitables, nous avons commencé, dans une première étape, par une vérification de la cohérence des résultats d’analyse, suivie d’une analyse conjointe de tous les paramètres pour explorer la structure globale des données et appréhender les principaux facteurs qui contrôlent l’évolution de la qualité physico-chimique des eaux.Nous proposons dans cette étude deux modèles mathématiques prévisionnels : le premier est un modèle de simulation du comportement de la qualité des eaux basé sur les relations concentration-débit. Le second est une approche prédictive qui permet de mettre en évidence les saisonnalités et les tendances d’évolution des paramètres étudiés.A river is a complex system in interaction with the whole of its catchment area. River water acquires its physicochemical composition under the combined action of several factors: weathering of rocks, decomposition of terrestrial organic matter, diffuse and point-source pollution, and atmospheric precipitation.The large catchment area of Tafna (7,245 km2 surface area), located at the extreme northwest sector of Algeria and extending into Moroccan territory (23%), is subdivided into four sub-basins. However, the downstream portion of the basin, which represents the sub-basin of maritime Tafna, was not retained in this study; its principal river Tafna is often dry because several hydraulic constructions have been installed in the upstream part of the basin. The three sub-basins concerned then with this study are the upper Tafna, the Mouillah and the Isser.In the basin of Tafna, surface water quality is being continually degraded. In addition to the phenomenon of erosion, which has been estimated to be 400 t/km2/year in the Mouillah sub-basin and 1,000 t/km2/year in the Isser and upper Tafna sub-basins, domestic and industrial wastes increasingly threaten the quality of the surface water.The basin of Tafna has a surface water quality network composed of 41 sampling stations. Three stations have been selected for this study. They are distributed in the three sub-basins studied, and are located upstream of dams, so as to cover the whole of the basin: Station ST160202 in the Mouillah sub-basin, ST160426 in the upper Tafna sub-basin and ST160614 in the Isser sub-basin. This work presents the results of an exploration of a series of instantaneous samples collected with at least monthly frequency over a period of seven years (April 1995-March 2002). The descriptors used in this study are the total concentrations: suspended matter concentration (SS), conductivity, which expresses the dissolved matter concentration, and the organic matter concentration as estimated with the chemical oxygen demand (COD).To be able to interpret the influence of the characteristics of the catchment area on the physicochemical quality of surface water, we started by describing the principal characteristics of the sub-basins studied. Given the great variability of the results of the analysis, we considered it to be useful and necessary to evaluate the coherence of the measurements with ion balance and statistical analysis (Box and Whisker plots). A joint analysis of all parameters was then applied to explore the total structure of the data in order to understand the principal factors that control the evolution of the physicochemical water quality.This study proposes two models. The first model is a simulation of the behaviour of surface water quality based on concentration-flow relations. The second is a predictive approach that makes it possible to highlight the seasonal effects and the temporal trends of the studied parameters.Based on this modelling, it appears that the concentration variance explained by the concentration-flow models varies between 50% and 72%, which means that the reconstitution of the concentrations is only approximate. To improve the reliability of these models, we propose several solutions.As for the forecasting models, a comparison of the values calculated to those measured shows that the results for conductivity and the COD are close to the measured values, with average relative variations of the order of 15%, but the forecasts of SS are considered to be less precise because they produce greater average relative variations. This is explained by the fact that the suspended matter concentrations do not follow a seasonal trend but are strongly related to flow variations.Finally, it should be noted that the reliability of the established models remains very sensitive to the size of the measurement series one has. Better information contained in longer series of analyses would undoubtedly make it possible to reduce this uncertainty.The methodology has been suggested on a purely exploratory basis and was limited to the three descriptors of the surface water quality: SS, conductivity and COD. The work will be extended by applying it to other parameters, which should make it possible to establish a complete model for the behaviour of surface water quality in the catchment area of the Tafna