Impulse distributions in dense granular flows: signatures of large-scale spatial structures

In this paper we report the results of simulations of a 2D gravity driven, dissipative granular flow through a hopper system. Measurements of impulse distributions P(I) on the simulated system show flow-velocity-invariant behavior of the distribution for impulses larger than the average impulse . For small impulses, however, P(I) decreases significantly with flow velocity, a phenomenon which can be attributed exclusively to collisions between grains undergoing frequent collisions. Visualizations of the system also show that these frequently colliding particles tend to form increasingly large linear clusters as the flow velocity decreases. A model is proposed for the form of P(I), given distributions of cluster size and velocity, which accurately predicts the observed form of the distribution. Thus the impulse distribution provides some insight into the formation and properties of these ``dynamic'' force chains.Comment: 4 pages, 4 figure

Using self-determination theory to understand African American women\u27s physical activity patterns

Physical inactivity is a major health risk factor in our society. Women and minority populations are especially at risk with regard to physical inactivity. This three-part study employed quantitative and qualitative methodologies to investigate physical activity behaviors in middle aged and older African American women. This population was chosen because African American women are the least active segment of our society. In the first phase, a quantitative approach was used to investigate relationships between Self-Determination and the Stage of Change for physical activity in a sample of 105 African American women. This study provided validation for using this theoretical approach in a population of African American women and provided a clearer understanding of the types of motivation most likely to contribute to the initiation and maintenance of exercise in this population. Guided by the underlying assumption that the reasons African American women choose to be active or inactive can only be fully understood by carefully examining their perspectives, a qualitative approach was used in the second and third phases of the study. Fifteen physically active and fifteen physically inactive women were purposively selected from the initial sample for in depth interviews in phase two. Categorical and contextual analysis indicated that perceptions of health status were a powerful influence on physical activity behavior. Perceptions of health status reflected the beliefs individuals held about a particular disease or physical condition, and the limitations they associated with that condition. In the third phase, six participants were selected for a multiple case study design. Cases analysis revealed that women shaped their physical activity patterns around their understanding of how physical activity would directly influence their desire to maintain independence from health costs, physical limitations related to their health, expected age related decline and their dependence on others. Across each phase of this project, identifying an individual’s level of motivation, as well as exploring the influences of that individual’s social context in a particular stage of change, has contributed to our understanding of factors to consider when developing effective behavior change interventions in this population

The Effects of Nutrition Package Claims, Nutrition Facts Panels, and Motivation to Process Nutrition Information on Consumer Product Evaluations

In a laboratory experiment using a between-subjects design, the authors examine the effects on nutrition and product evaluations of nutrition claims made (e.g., 99% fat free; low in calories ) on a product package, product nutrition value levels, and enduring motivation to process nutrition information. Enduring motivation is shown to moderate the effects of product nutrition value on consumer evaluations. Also, nutrition claims interact with product nutrition value in affecting consumer perceptions of manufacturer credibility. Given the availability of nutrient levels in the Nutrition Facts panel on the back of the mock package, nutrition claims on the front of the package generally did not affect positively consumers\u27 overall product and purchase intention evaluations. The authors discuss some implications of these findings, suggestions for further research, and study limitations

GravEn: Software for the simulation of gravitational wave detector network response

Physically motivated gravitational wave signals are needed in order to study the behaviour and efficacy of different data analysis methods seeking their detection. GravEn, short for Gravitational-wave Engine, is a MATLAB software package that simulates the sampled response of a gravitational wave detector to incident gravitational waves. Incident waves can be specified in a data file or chosen from among a group of pre-programmed types commonly used for establishing the detection efficiency of analysis methods used for LIGO data analysis. Every aspect of a desired signal can be specified, such as start time of the simulation (including inter-sample start times), wave amplitude, source orientation to line of sight, location of the source in the sky, etc. Supported interferometric detectors include LIGO, GEO, Virgo and TAMA.Comment: 10 Pages, 3 Figures, Presented at the 10th Gravitational Wave Data Analysis Workshop (GWDAW-10), 14-17 December 2005 at the University of Texas, Brownsvill

Cross reactive arrays of three-way junction sensors for steroid determination

This invention provides analyte sensitive oligonucleotide compositions for detecting and analyzing analytes in solution, including complex solutions using cross reactive arrays of analyte sensitive oligonucleotide compositions

Learning from FITS: Limitations in use in modern astronomical research

The Flexible Image Transport System (FITS) standard has been a great boon to astronomy, allowing observatories, scientists and the public to exchange astronomical information easily. The FITS standard, however, is showing its age. Developed in the late 1970s, the FITS authors made a number of implementation choices that, while common at the time, are now seen to limit its utility with modern data. The authors of the FITS standard could not anticipate the challenges which we are facing today in astronomical computing. Difficulties we now face include, but are not limited to, addressing the need to handle an expanded range of specialized data product types (data models), being more conducive to the networked exchange and storage of data, handling very large datasets, and capturing significantly more complex metadata and data relationships. There are members of the community today who find some or all of these limitations unworkable, and have decided to move ahead with storing data in other formats. If this fragmentation continues, we risk abandoning the advantages of broad interoperability, and ready archivability, that the FITS format provides for astronomy. In this paper we detail some selected important problems which exist within the FITS standard today. These problems may provide insight into deeper underlying issues which reside in the format and we provide a discussion of some lessons learned. It is not our intention here to prescribe specific remedies to these issues; rather, it is to call attention of the FITS and greater astronomical computing communities to these problems in the hope that it will spur action to address them