The signaling role of fiscal austerity

I build a model where creditworthy countries may use fiscal austerity to communicate their ability to repay sovereign debt and show that the signaling channel is active only for high levels of asymmetric information. The model generates a negative association between the amount of public information, provided by the rating agencies, and fiscal tightness. Informed by the model predictions, I build a model where creditworthy countries may use fiscal austerity to communicate their ability to repay sovereign debt and show that the signaling channel is active only for high levels of asymmetric information. The model generates a negative association between the amount of public information, provided by the rating agencies, and fiscal tightness. Informed by the model predictions, I perform an empirical investigation based on a panel of 58 OECD and emerging market economies since 1980 and find evidence of this signaling channel

Gender quotas in the boardroom: New evidence from Germany

We examine the introduction of a gender quota law in Germany, mandating a minimum 30% of the underrepresented gender on the supervisory boards of a particular type of firms. We exploit the fact that Germany has a two-tier corporate system consisting of the affected supervisory boards and unaffected management boards within the same firm. We find a positive effect on the female share on supervisory boards of affected firms, but no effect on presidency of the board or its size. We also study whether the increased female representation has had an effect on the financial performance of the firm and conclude that, unlike some previous studies in other countries, there has not been any negative effect on the profitability of the firm, neither at the time when the law was announced nor when it was passed

Simultaneous 3D measurement of the translation and rotation of finite size particles and the flow field in a fully developed turbulent water flow

We report a novel experimental technique that measures simultaneously in three dimensions the trajectories, the translation, and the rotation of finite size inertial particles together with the turbulent flow. The flow field is analyzed by tracking the temporal evolution of small fluorescent tracer particles. The inertial particles consist of a super-absorbent polymer that renders them index and density matched with water and thus invisible. The particles are marked by inserting at various locations tracer particles into the polymer. Translation and rotation, as well as the flow field around the particle are recovered dynamically from the analysis of the marker and tracer particle trajectories. We apply this technique to study the dynamics of inertial particles much larger in size (Rp/{\eta} \approx 100) than the Kolmogorov length scale {\eta} in a von K\'arm\'an swirling water flow (R{\lambda} \approx 400). We show, using the mixed (particle/fluid) Eulerian second order velocity structure function, that the interaction zone between the particle and the flow develops in a spherical shell of width 2Rp around the particle of radius Rp. This we interpret as an indication of a wake induced by the particle. This measurement technique has many additional advantages that will make it useful to address other problems such as particle collisions, dynamics of non-spherical solid objects, or even of wet granular matter.Comment: 18 pages, 7 figures, submitted to "Measurement Science and Technology" special issue on "Advances in 3D velocimetry

Subtraction of temperature induced phase noise in the LISA frequency band

Temperature fluctuations are expected to be one of the limiting factors for gravitational wave detectors in the very low frequency range. Here we report the characterisation of this noise source in the LISA Pathfinder optical bench and propose a method to remove its contribution from the data. Our results show that temperature fluctuations are indeed limiting our measurement below one millihertz, and that their subtraction leads to a factor 5.6 (15 dB) reduction in the noise level at the lower end of the LISA measurement band 10^{-4} Hz, which increases to 20.2 (26 dB) at even lower frequencies, i.e., 1.5x10^{-5} Hz. The method presented here can be applied to the subtraction of other noise sources in gravitational wave detectors in the general situation where multiple sensors are used to characterise the noise source.Comment: 8 pages, 6 figure

Genetic and plastic rewiring of food webs under climate change

Climate change is altering ecological and evolutionary processes across biological scales. These simultaneous effects of climate change pose a major challenge for predicting the future state of populations, communities and ecosystems. This challenge is further exacerbated by the current lack of integration of research focused on these different scales. We propose that integrating the fields of quantitative genetics and food web ecology will reveal new insights on how climate change may reorganize biodiversity across levels of organization. This is because quantitative genetics links the genotypes of individuals to population-level phenotypic variation due to genetic (G), environmental (E) and gene-by-environment (G × E) factors. Food web ecology, on the other hand, links population-level phenotypes to the structure and dynamics of communities and ecosystems. We synthesize data and theory across these fields and find evidence that genetic (G) and plastic (E and G × E) phenotypic variation within populations will change in magnitude under new climates in predictable ways. We then show how changes in these sources of phenotypic variation can rewire food webs by altering the number and strength of species interactions, with consequences for ecosystem resilience. We also find evidence suggesting there are predictable asymmetries in genetic and plastic trait variation across trophic levels, which set the pace for phenotypic change and food web responses to climate change. Advances in genomics now make it possible to partition G, E and G × E phenotypic variation in natural populations, allowing tests of the hypotheses we propose. By synthesizing advances in quantitative genetics and food web ecology, we provide testable predictions for how the structure and dynamics of biodiversity will respond to climate change

Integrating clinicians, knowledge and data: expert-based cooperative analysis in healthcare decision support

<p>Abstract</p> <p>Background</p> <p>Decision support in health systems is a highly difficult task, due to the inherent complexity of the process and structures involved.</p> <p>Method</p> <p>This paper introduces a new hybrid methodology <it>Expert-based Cooperative Analysis </it>(EbCA), which incorporates explicit prior expert knowledge in data analysis methods, and elicits implicit or tacit expert knowledge (IK) to improve decision support in healthcare systems. EbCA has been applied to two different case studies, showing its usability and versatility: 1) Bench-marking of small mental health areas based on technical efficiency estimated by <it>EbCA-Data Envelopment Analysis (EbCA-DEA)</it>, and 2) Case-mix of schizophrenia based on functional dependency using <it>Clustering Based on Rules (ClBR)</it>. In both cases comparisons towards classical procedures using qualitative explicit prior knowledge were made. Bayesian predictive validity measures were used for comparison with expert panels results. Overall agreement was tested by Intraclass Correlation Coefficient in case "1" and kappa in both cases.</p> <p>Results</p> <p>EbCA is a new methodology composed by 6 steps:. 1) Data collection and data preparation; 2) acquisition of "Prior Expert Knowledge" (PEK) and design of the "Prior Knowledge Base" (PKB); 3) PKB-guided analysis; 4) support-interpretation tools to evaluate results and detect inconsistencies (here <it>Implicit Knowledg </it>-IK- might be elicited); 5) incorporation of elicited IK in PKB and repeat till a satisfactory solution; 6) post-processing results for decision support. EbCA has been useful for incorporating PEK in two different analysis methods (DEA and Clustering), applied respectively to assess technical efficiency of small mental health areas and for case-mix of schizophrenia based on functional dependency. Differences in results obtained with classical approaches were mainly related to the IK which could be elicited by using EbCA and had major implications for the decision making in both cases.</p> <p>Discussion</p> <p>This paper presents EbCA and shows the convenience of completing classical data analysis with PEK as a mean to extract relevant knowledge in complex health domains. One of the major benefits of EbCA is iterative elicitation of IK.. Both explicit and tacit or implicit expert knowledge are critical to guide the scientific analysis of very complex decisional problems as those found in health system research.</p

Optically switched magnetism in photovoltaic perovskite CH3_3NH3_3(Mn:Pb)I3_3

The demand for ever-increasing density of information storage and speed of manipulation boosts an intense search for new magnetic materials and novel ways of controlling the magnetic bit. Here, we report the synthesis of a ferromagnetic photovoltaic CH$_3$NH$_3$(Mn:Pb)I$_3$ material in which the photo-excited electrons rapidly melt the local magnetic order through the Ruderman-Kittel-Kasuya-Yosida interactions without heating up the spin system. Our finding offers an alternative, very simple and efficient way of optical spin control, and opens an avenue for applications in low power, light controlling magnetic devices

Determinación ponderal de fibras en una mezcla y relación entre diametro y densidad aparente de la lana

Se hace un estudio crítico de los métodos corrientemente empleados en análisis de mezclas de fibras por microscopía, haciendo notar la imposibilidad de poder obtener resultados relativamente exactos al analizar mezclas en las que algunos de sus componentes son fibras celulósicas o proteicas, debido a que en los cálculos intervienen datos como el diámetro y la densidad de las mismas. El primero es determinado sin tener en cuenta que la fibra presenta poros sensibles dando lugar a un volumen aparente que al ser mayor que el volumen real (volumen de masa fibrilar sin huecos), hace que tenga que considerarse una densidad aparente, necesariamente menor que la real. El trabajo se orientó en el sentido de hallar un método factible de poder determinar la densidad aparente de cada fibra, con objeto de utilizarla en las fórmulas y método de análisis por contaje ya establecidos. Se determinó la densidad aparente de la lana en sus distintos tipos, encontrándose una correlación entre el diámetro y la densidad aparente, de la cual se deduce la ecuación analítica que liga estas dos variablesPeer Reviewe