Zeroth Poisson homology of symmetric powers of isolated quasihomogeneous surface singularities

Let X be a surface with an isolated singularity at the origin, given by the equation Q(x,y,z)=0, where Q is a weighted-homogeneous polynomial. In particular, this includes the Kleinian surfaces X = C^2/G for G < SL(2,C) finite. Let Y be the n-th symmetric power of X. We compute the zeroth Poisson homology of Y, as a graded vector space with respect to the weight grading. In the Kleinian case, this confirms a conjecture of Alev, that the zeroth Poisson homology of the n-th symmetric power of C^2/G is isomorphic to the zeroth Hochschild homology of the n-th symmetric power of the algebra of G-invariant differential operators on C. That is, the Brylinski spectral sequence degenerates in this case. In the elliptic case, this yields the zeroth Hochschild homology of symmetric powers of the elliptic algebras with three generators modulo their center, for the parameter equal to all but countably many points of the elliptic curve.Comment: 17 page

Health-related Quality of Life and Informed Decision-making in Lung Cancer Screening

Lung cancer is worldwide the most common form of cancer and the most common cause of death from cancer. It accounts for approximately 28% of all cancer deaths. World-wide 1.2 million people die from lung cancer each year. In the Netherlands, 9,918 people died from lung cancer in 2008. Lung cancer is often diagnosed in an advanced incurable stage. Despites advances in treatment, 85% or more patients will die within 5 years after diagnosis. In the Netherlands, the mortality-incidence ratio is 95%. Total costs of lung cancer in the Netherlands were estimated to be 193 million euro in 2005

Using Bars As Signposts of Galaxy Evolution at High and Low Redshifts

An analysis of the NICMOS Deep Field shows that there is no evidence of a decline in the bar fraction beyond z~0.7, as previously claimed; both bandshifting and spatial resolution must be taken into account when evaluating the evolution of the bar fraction. Two main caveats of this study were a lack of a proper comparison sample at low redshifts and a larger number of galaxies at high redshifts. We address these caveats using two new studies. For a proper local sample, we have analyzed 134 spirals in the near-infrared using 2MASS (main results presented by Menendez-Delmestre in this volume) which serves as an ideal anchor for the low-redshift Universe. In addition to measuring the mean bar properties, we find that bar size is correlated with galaxy size and brightness, but the bar ellipticity is not correlated with these galaxy properties. The bar length is not correlated with the bar ellipticity. For larger high redshift samples we analyze the bar fraction from the 2-square degree COSMOS ACS survey. We find that the bar fraction at z~0.7 is ~50%, consistent with our earlier finding of no decline in bar fraction at high redshifts.Comment: In the proceedings of "Penetrating Bars through Masks of Cosmic Dust: The Hubble Tuning Fork strikes a New Note

Interdisciplinary design of a pervasive fall handling system

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The Role of Land in Economic Theory

Changes in land use and land cover are among the issues central to the study of global environmental change. In addition to their cumulative long-term global dimensions, such changes can have profound regional environmental implications during the life span of current generations. A better understanding of the dynamics in land and water use is thus critical for an informed debate of sustainability. Land use represents a critical intersection of economic and ecological systems. Land-use changes are most often directly linked with economic decisions. This recognition has led LUC to choose an economic framework as the organizing principle, resulting in a broad set of project activities geared towards providing a biophysical and geographical underpinning to the representation of land-based economic sectors in modeling land and water use decisions. This report addresses foremost researchers outside economics and should be viewed as a modest step towards reducing the deficit in transdisciplinary research, which, until now, has permitted only modest advances in closing the gaps between environment and economic analysis. The role of land in economic theory is surveyed, both from a conceptual and historical perspective. Land has been incorporated in economic theories in various ways. Originally, land used by agriculture was the main motivation for an economic treatment of land. This was gradually extended with various other land use categories. Neoclassical core economic theory gave less attention to land use, generally regarding it as a production factor of relatively little importance. Nevertheless specialized sub-fields within economics such as regional and urban economics met the demand for explicit spatial analysis including land use considerations. More recently, attention for environmental and resource problems has provided incentives for new perspectives on, and conceptualization of, land in economic analysis. To some extent, this is based on an interaction with other disciplines as well as on the use of spatially disaggregate methods of analysis

On the negative spectrum of two-dimensional Schr\"odinger operators with radial potentials

For a two-dimensional Schr\"odinger operator $H_{\alpha V}=-\Delta-\alpha V$ with the radial potential $V(x)=F(|x|), F(r)\ge 0$, we study the behavior of the number $N_-(H_{\alpha V})$ of its negative eigenvalues, as the coupling parameter $\alpha$ tends to infinity. We obtain the necessary and sufficient conditions for the semi-classical growth $N_-(H_{\alpha V})=O(\alpha)$ and for the validity of the Weyl asymptotic law.Comment: 13 page

Latent class trees with the three-step approach

Latent class (LC) analysis is widely used in the social and behavioral sciences to find meaningful clusters based on a set of categorical variables. To deal with the common problem that a standard LC analysis may yield a large number classes and thus a solution that is difficult to interpret, recently an alternative approach has been proposed, called Latent Class Tree (LCT) analysis. It involves starting with a solution with a small number of "basic" classes, which may subsequently be split into subclasses at the next stages of an analysis. However, in most LC analysis applications, we not only wish to identify the relevant classes, but also want to see how they relate to external variables (covariates or distal outcomes). For this purpose, researchers nowadays prefer using the bias-adjusted three-step method. Here, we show how this bias-adjusted three-step procedure can be applied in the context of LCT modeling. More specifically, an R-package is presented that performs a three-step LCT analysis: it builds a LCT and allows checking how splits are related to the relevant external variables. The new tool is illustrated using a cross-sectional application with multiple indicators on social capital and demographics as external variables and with a longitudinal application with a mood variable measured multiple times during the day and personality traits as external variables