Measuring the Lifetime of Trapped Sleptons Using the General Purpose LHC Detectors

In supergravity where the gravitino is the lightest supersymmetric particle (LSP), the next-to-lightest supersymmetric particle (NLSP) decays to the gravitino with a naturally long lifetime (10^4 - 10^8). However, cosmological constraints favour charged sleptons with lifetimes below a year as the natural NLSP candidate. For this scenario we report a method to accurately determine the slepton lifetime and SUSY cross-section from observation of the decays of sleptons trapped in the material comprising the main detector (ATLAS, CMS). A measurement of the lifetime to 5% is possible after 3 years at nominal luminosity and running conditions. This method is sensitive to the cosmologically preferred stau lifetime of ~37 days and does not require the use of ancillary trapping volumes

SNS Timing System

This poster describes the timing system being designed for Spallation Neutron Source being built at Oak Ridge National lab

Location-aware alert system for mobile devices

Being able to react fast to campaign events such as missing persons or disaster preventions, is of paramount importance. In these situations narrowing down the search area to a targeted and accurate location is imperative. Nowadays, modern mobile devices have the location awareness capabilities that can be used to determine the users Global Positioning System (GPS) coordinates. However in order to determine if a user is located within a specific area, complex floating point calculations are required. Moreover if the area is determined by a polygon, this calculation is further complicated. In this paper we propose a novel algorithm which makes use of spatial indices to determine if a mobile is located within a predefined polygon shape area. The algorithm determines the optimal length of the spatial index such as to ensure accuracy-processing time-memory trade-off. We build a prototype system, using free and open source software, to deliver alerts to mobile devices within a predetermined geographical area. The system is assessed in terms of accuracy, processing time and memory usage

First light for avian embryos: eggshell thickness and pigmentation mediate variation in development and UV exposure in wild bird eggs

Article first published online: 29 JUL 20141. The avian embryo's development is influenced by both the amount and the wavelength of the light that passes through the eggshell. Commercial poultry breeders use light of specific wavelengths to accelerate embryonic growth, yet the effects of the variably patterned eggshells of wild bird species on light transmission and embryonic development remain largely unexplored. 2. Here, we provide the first comparative phylogenetic analysis of light transmission, through a diverse range of bird eggshells (74 British breeding species), in relation to the eggshell's thickness, permeability, pigment concentration and surface reflectance spectrum (colour). 3. The percentage of light transmitted through the eggshell was measured in the spectral range 250–700 nm. Our quantitative analyses confirm anecdotal reports that eggshells filter the light of the externally coloured shell. Specifically, we detected a positive relationship between surface eggshell reflectance (‘brightness’) and the percentage of light transmitted through the eggshell, and this relationship was strongest at wavelengths in the human-visible blue-green region of the spectra (c. 435 nm). 4. We show that less light passes through thicker eggshells with greater total pigment concentrations. By contrast, permeability (measured as water vapour conductance) did not covary significantly with light transmission. Eggs of closed-nesting species let more light pass through, compared with open nesters. 5. We postulate that greater light transmission is required to assist embryonic development under low light exposure. Importantly, this result provides an ecological explanation for the repeated evolution of immaculate, white- or pale-coloured eggshells in species nesting in enclosed spaces. 6. Finally, we detected correlative support for the solar radiation hypothesis, in that eggshells of bird species with a longer incubation period let significantly less of the potentially harmful, ultraviolet (UV) light pass through the eggshell. In summary, we demonstrate suites of avian eggshell properties, including eggshell structure and pigmentation, which are consistent with an evolutionary pressure to both enhance and protect embryonic development.Golo Maurer, Steven J. Portugal, Mark E. Hauber, Ivan Mikšík, Douglas G. D. Russell and Phillip Casse

Mobilizing Cause Supporters through Group-Based Interaction

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.Collective action expresses group-based identities, formed by supporters seeking to further particular social causes. While the development of groups linked to action necessitates interaction among supporters, little research has examined how these groups form. Utilizing responses of supporters who participated in 1 of 29 action-planning sessions, this research presents an initial attempt to identify the ingredients important to this process. It shows that to the extent that the actions agreed on in the course of group interactions were seen as capable of making a difference (action efficacy), and worthy of public expression (action voice), supporters’ group-based identification was enhanced. This in turn increased their willingness to engage in collective action. Practical implications and avenues for future research to understand the mobilization process are discussed.Australian Research Counci

Fluid structure in the immediate vicinity of an equilibrium three-phase contact line and assessment of disjoining pressure models using density functional theory

We examine the nanoscale behavior of an equilibrium three-phase contact line in the presence of long-ranged intermolecular forces by employing a statistical mechanics of fluids approach, namely density functional theory (DFT) together with fundamental measure theory (FMT). This enables us to evaluate the predictive quality of effective Hamiltonian models in the vicinity of the contact line. In particular, we compare the results for mean field effective Hamiltonians with disjoining pressures defined through (I) the adsorption isotherm for a planar liquid film, and (II) the normal force balance at the contact line. We find that the height profile obtained using (I) shows good agreement with the adsorption film thickness of the DFT-FMT equilibrium density profile in terms of maximal curvature and the behavior at large film heights. In contrast, we observe that while the height profile obtained by using (II) satisfies basic sum rules, it shows little agreement with the adsorption film thickness of the DFT results. The results are verified for contact angles of 20, 40 and 60 degrees