Nonsplit conics in the reduction of an arithmetic curve

For an algebraic function field $F/K$ and a discrete valuation $v$ of $K$ with perfect residue field $k$, we bound the number of discrete valuations on $F$ extending $v$ whose residue fields are algebraic function fields of genus zero over $k$ but not ruled. Assuming that $K$ is relatively algebraically closed in $F$, we find that the number of nonruled residually transcendental extensions of $v$ to $F$ is bounded by $\mathfrak{g}+1$ where $\mathfrak{g}$ is the genus of $F/K$. An application to sums of squares in function fields of curves over $\mathbb{R}(\!(t)\!)$ is presented

Robust Multiperiod Poverty Comparisons

We propose a new methodology for comparing poverty over multiple periods across time and space that does not arbitrarily aggregate income over various years or rely on arbitrarily specified poverty lines or poverty indices. Following Duclos et al. (2006a), we use the multivariate stochastic dominance methodology to create dominance surfaces for different time spans. We elaborate the method first for the bidimensional case, using as dimensions income observed over two periods: one at the beginning and one at the end of a time span. Subsequently, we extend it to the case where incomes are observed over n-periods. We illustrate our approach by performing poverty comparisons using data for Indonesia and Peru.Multiperiod Poverty, Poverty Dominance, Poverty Dynamics, Chronic Poverty

Robust Multiperiod Poverty Comparisons

We propose a methodology for comparing poverty over multiple periods across time and space without arbitrarily aggregating income over various years or relying on arbitrarily specified poverty lines. Following Duclos et al. (2006a), we use the multivariate stochastic dominance methodology to create dominance surfaces for different time spans. We elaborate the method for the bi-dimensional case, using income observed over two periods, one at the beginning and one at the end of a time span, as dimensions. We also embed in this framework a new concept of chronic and transient poverty. We illustrate our approach by performing poverty comparisons using data for Indonesia and Peru. --Chronic Poverty,Multiperiod Poverty,Poverty Dominance,Poverty Dynamics,Transient Poverty

Spatial inequalities explained - Evidence from Burkina Faso

The literature shows that regional disparities in growth and poverty are often relatively high, that these regional disparities do not necessarily disappear as the economies grow and develop and that these disparities are itself in many cases an important driver of the overall performance of an economy. In this paper we make use of the advantage of a multilevel random coefficient model to explain spatial disparities in incomes among Burkinab`e households. Our findings show that it is not a geographical concentration of people with poor endowments that make areas poor in Burkina Faso. Household income disparities are largely driven by differences in neighborhood endowments and to a smaller extent by provincial or regional characteristics. We conclude that the policy should target small scale geographical units, such as villages. Providing infrastructure, enhancing the functioning of labor markets and fostering demand for education can compensate for climatical disadvantages.Spatial inequality, poverty, multilevel modeling, decomposition, Sub-Saharan Africa

Inducing an optical Feshbach resonance via stimulated Raman coupling

We demonstrate a novel method of inducing an optical Feshbach resonance based on a coherent free-bound stimulated Raman transition. In our experiment atoms in a Rb87 Bose-Einstein condensate are exposed to two phase-locked Raman laser beams which couple pairs of colliding atoms to a molecular ground state. By controlling the power and relative detuning of the two laser beams, we can change the atomic scattering length considerably. The dependence of scattering length on these parameters is studied experimentally and modelled theoretically.Comment: 8 pages, 8 figures, submitted to PR

Spatial inequalities explained: evidence from Burkina Faso

Empirical evidence suggests that regional disparities in incomes are often very high, that these disparities do not necessarily disappear as economies grow and that these disparities are itself an important driver of growth. We use a novel approach based on multilevel modeling to decompose the sources of spatial disparities in incomes among households in Burkina Faso. We show that spatial disparities are not only driven by the spatial concentration of households with particular endowments but to a large extent also by disparities in community endowments. Climatic differences across regions do also matter, but to a much smaller extent

Interaktive Echtzeitmodellierung von biologischem Gewebe für Virtuelle Realitäten in der medizinischen Ausbildung

In der vorliegenden Arbeit wird die interaktive Echtzeitmodellierung von biologischem Gewebe für Virtuelle Realitäten in der medizinischen Ausbildung diskutiert. Bestehende und neu entwickelte Ansätze zur Modellierung von Gewebedeformationen und -reißen werde vorgestellt, verglichen und bewertet. Die erstellte Softwarearchitektur wird vorgestellt. Außerdem werden die im Rahmen dieser Arbeit entwickelten und durchgeführten medizinischen Simulationen beschrieben

Die Bedeutung von Säumen im großflächigen Ökologischen Landbau

Establishing a system of field margins for enhancing the floristic and faunistic biodiversity on a Demeter farm in north-east Germany is part of the project “Nature conservation farm Brodowin”, which analyses potential conflicts between nature conservation demands and large-scale organic agriculture. In cooperation with the Demeter farm Ökodorf Brodowin several possibilities for the special management of field margins are tested, which meet the demands of target species as well as fit in the agricultural process. Field margins from 3 to 20m are excluded from ploughing, partly set aside and partly mown once or twice a year. First results show that these field margins serve as habitat and source-area for a large variety of species. For example, density and reproduction of grasshoppers is high, especially on margins with poor soils. From the agricultural point of view, unploughed field margins can facilitate farming procedures. Depending on the quantity and quality of the fodder, it can be integrated into animal nutrition