Using the Discrete Dipole Approximation and Holographic Microscopy to Measure Rotational Dynamics of Non-spherical Colloidal Particles

We present a new, high-speed technique to track the three-dimensional translation and rotation of non-spherical colloidal particles. We capture digital holograms of micrometer-scale silica rods and sub-micrometer-scale Janus particles freely diffusing in water, and then fit numerical scattering models based on the discrete dipole approximation to the measured holograms. This inverse-scattering approach allows us to extract the the position and orientation of the particles as a function of time, along with static parameters including the size, shape, and refractive index. The best-fit sizes and refractive indices of both particles agree well with expected values. The technique is able to track the center of mass of the rod to a precision of 35 nm and its orientation to a precision of 1.5$^\circ$, comparable to or better than the precision of other 3D diffusion measurements on non-spherical particles. Furthermore, the measured translational and rotational diffusion coefficients for the silica rods agree with hydrodynamic predictions for a spherocylinder to within 0.3%. We also show that although the Janus particles have only weak optical asymmetry, the technique can track their 2D translation and azimuthal rotation over a depth of field of several micrometers, yielding independent measurements of the effective hydrodynamic radius that agree to within 0.2%. The internal and external consistency of these measurements validate the technique. Because the discrete dipole approximation can model scattering from arbitrarily shaped particles, our technique could be used in a range of applications, including particle tracking, microrheology, and fundamental studies of colloidal self-assembly or microbial motion.Comment: 11 pages, 9 figures, 2 table

Improving Performance and Participation of Elementary School Students through a Coteaching Model

This project explored the use of a coteaching program with a general education teacher and OTD student at an elementary school. The poster provides an overview of the methods used, an overview of the coteaching program that was implemented, and the significance and implications of this project. The purpose of this coteaching program was to develop a coteaching program in which occupational therapists and general education teachers work together in classrooms to improve performance and participation of students with and without disabilities.https://soar.usa.edu/otdcapstonesspring2023/1034/thumbnail.jp

How relationship norms shape moral obligation in cancelation behavior

Shuqair, S., Costa Pinto, D., Cruz-Jesus, F., Mattila, A. S., da Fonseca Guerreiro, P., & Kam Fung So, K. (2022). Can customer relationships backfire? : How relationship norms shape moral obligation in cancelation behavior. Journal of Business Research, 151(November), 463-472. https://doi.org/10.1016/j.jbusres.2022.07.008 ---Funding Information: The authors Diego and Frederico gratefully acknowledge financial support from FCT Fundação para a Ciência e a Tecnologia (Portugal), national funding through research grant Information Management Research Center – MagIC/NOVA IMS (UIDB/04152/2020).While prior research indicates that establishing interpersonal interaction with customers is mostly beneficial, this work reveals that the impact of social ties depends on relationship norms (communal vs. exchange). In three studies, including a real-world field dataset (N = 87,615 customers), the current investigation demonstrates the conditions under which interpersonal relationships can increase or decrease customers’ cancelation behavior. The findings indicate that communal (vs. exchange) relationships can increase customers’ future cancelation behaviors. The findings also demonstrate that perceived moral obligation underlies interpersonal effects on cancelation behavior. That is, when providers develop communal (vs. exchange) ties, consumers feel that their interaction with the providers is in a closed social context, which tends to reduce their obligations towards attending their booking, thus increasing cancelation behavior. Theoretical and practical implications for business researchers and practitioners are discussed.publishersversionpublishe

Empowerment evaluation of a Swedish gender equity plan

Background: Empowerment is essential for gender equity and health. The city of Malmö, Sweden, has formulated a development plan for gender equity integration (GEIDP). A ‘Policy Empowerment Index’ (PEI) was previously developed to assess the empowerment potential of policies. Objectives: To pilot-evaluate the GEIDP's potential for empowerment and to test the PEI for future policy evaluations. Design: The GEIDP was analyzed and scored according to electronically retrieved evidence on constituent opinion, participation, capacity development, evaluation–adaptation, and impact. Results: The plan's PEI score was 64% (CI: 48–78) and was classified as ‘enabling’, ranging between ‘enabling’ and ‘supportive’. The plan's strengths were: 1) constituent knowledge and concern; 2) peripheral implementation; 3) protection of vulnerable groups; and 4) evaluation/adaptation procedures. It scored average on: 1) policy agenda setting; 2) planning; 3) provisions for education; 4) network formation; 5) resource mobilization. The weakest point was regarding promotion of employment and entrepreneurship. Conclusions: The PEI evaluation highlighted the plan's potential of constituency empowerment and proposed how it could be augmented

The costs of scaling up HIV prevention for high risk groups: lessons learned from the Avahan Programme in India.

OBJECTIVE: The study objective is to measure, analyse costs of scaling up HIV prevention for high-risk groups in India, in order to assist the design of future HIV prevention programmes in South Asia and beyond. DESIGN: Prospective costing study. METHODS: This study is one of the most comprehensive studies of the costs of HIV prevention for high-risk groups to date in both its scope and size. HIV prevention included outreach, sexually transmitted infections (STI) services, condom provision, expertise enhancement, community mobilisation and enabling environment activities. Economic costs were collected from 138 non-government organisations (NGOs) in 64 districts, four state level lead implementing partners (SLPs), and the national programme level (Bill and Melinda Gates Foundation (BMGF)) office over four years using a top down costing approach, presented in US$2011. RESULTS: Mean total unit costs (2004-08) per person reached at least once a year and per monthly contact were US$ 235(56-1864) and US$82(12-969) respectively. 35$ 477 per person reached in 2004 to US$145 per person reached in 2008). At the service level also unit costs decreased slightly over time from US$ 68 to US$ 64 per person reached. CONCLUSIONS: Scaling up HIV prevention for high risk groups requires significant investment in expertise enhancement and programme administration. However, unit costs decreased with programme expansion in spite of an increase in the scope of activities