Reconstructing Dark Matter Density with e^+e^- Linear Collider in Focus-Point Supersymmetry

It has been known that, in the focus point scenario of supersymmetry, the thermal relic of the lightest superparticle (LSP) is known to be a good candidate of the cold dark matter. Assuming that the LSP in the focus-point scenario be the cold dark matter, we address a question how and how well the relic density of the LSP can be determined once the superparticles are found at future e^+e^- linear collider. We will see that the determinations of the mass of the LSP as well as those of the Higgsino-like chargino and neutralinos, which will be possible by a study of the decay kinematics of the chargino or by threshold scan, will give us important information to theoretically reconstruct the relic density. Even if the Higgsino-like superparticles and the LSP are the only superparticles which are kinematically accessible, relic density of the LSP may be calculated with the accuracy of factor \sim 2; by adopting a mild theoretical assumption or by determining the masses of the Wino-like superparticles, uncertaintiy can be reduced to \sim 10 % or smaller.Comment: 13 pages, 4 figure

Computing a Compact Spline Representation of the Medial Axis Transform of a 2D Shape

We present a full pipeline for computing the medial axis transform of an arbitrary 2D shape. The instability of the medial axis transform is overcome by a pruning algorithm guided by a user-defined Hausdorff distance threshold. The stable medial axis transform is then approximated by spline curves in 3D to produce a smooth and compact representation. These spline curves are computed by minimizing the approximation error between the input shape and the shape represented by the medial axis transform. Our results on various 2D shapes suggest that our method is practical and effective, and yields faithful and compact representations of medial axis transforms of 2D shapes.Comment: GMP14 (Geometric Modeling and Processing

Effects of Urban Imperviousness Scenarios on Simulated Storm Flow

The amount and distribution of impervious surfaces are important input parameters of hydrological models, especially in highly urbanized basins. This study tests three different methods to input impervious surface area information to a semi-distributed hydrological model in order to examine their effects on storm flow. The three methods being evaluated include: (1) a constant value for impervious surfaces in the entire urban area, (2) constant values of imperviousness for commercial and residential land uses, respectively, and (3) different imperviousness for the residential land use in each subbasin. Storm flow of the Milwaukee River Basin in southeastern Wisconsin (USA) was modeled using the Hydrological Simulation Program–Fortran. The results show that the three methods resulted in substantially different amounts of storm flow. The storm flow simulated with the third method was the largest and had the largest variability among the subbasins. The differences among the scenarios are generally larger in subbasins with high percentage of urban land use types. The results suggest that the effect of different input methods is amplified in urbanized subbasins and the spatial variability of imperviousness should be commensurate with the spatial variability of the model configuration

Density-tunable non-close-packed monolayer of silica nanospheres prepared by single-step freeze-drying

The formation of density-tunable non–close-packed (ncp) monolayers of silica nanospheres via freeze drying is demonstrated. Monolayers of silica spheres with diameters of 120, 490, and 990 nm are achieved through a single-step freeze dry process. The densities of the spheres can be tuned by adjusting either the volume fraction of the spheres or the settling time before freezing. Issues involving defect-formation and defect-reduction are investigated. The experimental data suggest that this freeze drying method represents an efficient and robust way for achieving ncp monolayers of nanoparticles.published_or_final_versio

Analysis of the Neutralino System in Three--Body Leptonic Decays of Neutralinos

Neutralinos $\tilde{\chi}^0$ in supersymmetric theories, the spin--1/2 Majorana--type superpartners of the U(1) and SU(2) neutral electroweak gauge bosons and SU(2) neutral Higgs bosons, are expected to be among light supersymmetric particles so that they can be produced copiouslyvia direct pair production and/or from cascade decays of other sparticles such as sleptons at the planned Large Hadron Collider and the prospective International Linear Collider. Considering the prospects of having both highly polarized neutralinos and possibility of reconstructing their decay rest frames, we provide a systematic investigation of the three--body leptonic decays of the neutralinos in the minimal supersymmetric standard model and demonstrate alternative ways for probing the Majorana nature of the neutralinos and CP violation in the neutralino system.Comment: Version to appear in Eur.Phys.J.

A Conceptual Modeling Framework for Hydrologic Ecosystem Service

Ecosystem services (ES) help people understand and deal with current environmental situations and problems, and ES-related research has been increasing recently. However, the quantitative evaluations of ES that can be easily understood by decision makers are still in development. Specifically, new methods are needed for hydrologic ES with the requirements of spatially and temporally explicit specification of parameters related to climate, geology, land cover, soil, and topography. This paper presents a conceptual modeling framework that aims to convert hydrologic information to hydrologic ES in fine temporal resolutions by developing a conceptual connection of three modules: data development, hydrologic and ES modeling, and results analysis. Then, the framework was applied to a study basin to demonstrate the importance of hydrologic ES in fine temporal resolutions. Results of water provision ES, flood control ES, and sediment regulation ES were produced at fine temporal resolutions in the framework, which indicates that more timely and relevant policy suggestions can be provided to decision makers. The framework and the methodology are applicable for watersheds of varied sizes and can serve as a template for future coupling of different environmental models

Impacts of Climate Change and Urban Expansion on Hydrologic Ecosystem Services in the Milwaukee River Basin

Land use/land cover (LULC) and climate changes could affect water quantity and quality and thus hydrologic ecosystem services (ES). However, studies of these impacts on hydrologic ES are limited by the current methods and techniques. We attempted to find out how the LULC and climate changes impact hydrologic ES at different temporal scales so that decision-makers can easily understand hydrologic ES variations for guiding management plans. In this study, we analyzed the impacts of LULC and climate changes on hydrologic ES in the Milwaukee River basin, USA with a conceptual modeling framework for hydrologic ES. The model framework was applied to a series of climate and urban expansion scenarios. Two hydrologic responses (streamflow and sediment) and three hydrologic ES (water provision index (WPI), flood regulation index (FRI), and sediment regulation index (SRI)) were calculated. Major findings include: (1) Climate change has much larger impacts than LULC at the monthly scale. For example, the impacts of climate change on streamflow were −6 to 9 m3/s whereas those of LULC change were −0.4 to 0.2 m3/s. Also, WPI (ranging from 0 to 1) changed between −0.16 and 0.07 with climate change but between −0.02 and −0.001 with LULC changes. (2) Compared to changes at the annual scale, the results show much larger variabilities as monthly time-series and mean monthly numbers. These findings suggest that the climate change weighs more than the realistic LULC change in term of impacts on hydrologic ES and those impacts can be identified with results at the monthly temporal scale. This approach with the framework and scenarios can better support management planning for decision-makers with detailed results and temporal precision

Predictive Supersymmetry from Criticality

Motivated by the absence of any direct signal of new physics so far, we present a simple supersymmetric model in which the up-type Higgs mass-squared parameter crosses zero at a scale close to the weak scale. Such a theory may be motivated either by the conventional naturalness picture or by the landscape picture with certain assumptions on prior probability distributions of parameters. The model arises from a simple higher dimensional setup in which the gauge and Higgs fields propagate in the bulk while the matter fields are on a brane. The soft supersymmetry breaking parameters receive contributions from both moduli and anomaly mediations, and their weak scale values can be analytically solved for in terms of a single overall mass scale M. The expected size for M depends on whether one adopts the naturalness or landscape pictures, allowing for the possibility of distinguishing between these two cases. We also present possible variations of the model, and discuss more general implications of the landscape picture in this context.Comment: 18 pages, 4 figures, reference adde

Sperm trajectories form chiral ribbons.

We report the discovery of an entirely new three-dimensional (3D) swimming pattern observed in human and horse sperms. This motion is in the form of 'chiral ribbons', where the planar swing of the sperm head occurs on an osculating plane creating in some cases a helical ribbon and in some others a twisted ribbon. The latter, i.e., the twisted ribbon trajectory, also defines a minimal surface, exhibiting zero mean curvature for all the points on its surface. These chiral ribbon swimming patterns cannot be represented or understood by already known patterns of sperms or other micro-swimmers. The discovery of these unique patterns is enabled by holographic on-chip imaging of >33,700 sperm trajectories at >90-140 frames/sec, which revealed that only ~1.7% of human sperms exhibit chiral ribbons, whereas it increases to ~27.3% for horse sperms. These results might shed more light onto the statistics and biophysics of various micro-swimmers' 3D motion