Optimal designs for stated choice experiments that incorporate position effects

Davidson and Beaver (1977) extended the Bradley-Terry model to incorporate the possible effect of position within a choice set on the choices made in paired comparisons experiments. We further extend the Davidson-Beaver result to choice sets of any size and show, under a mild restriction, that designs optimal for the multinomial logit model are still optimal. Designs balanced for carry-over effects of all orders can be used to construct designs with a diagonal information matrix for attribute effects. The theoretical results are derived assuming equal merits and we discuss the possible consequences of assuming unequal merits in an example. Copyright © Taylor & Francis Group, LLC

Optimal designs for stated choice experiments that incorporate ties

In 1970 Davidson generalised the Bradley-Terry model to allow respondents to say that the two options presented in a choice task were equally attractive. In this paper we extend this idea to the MNL model with m options in each choice set and we show that the optimal designs for the MNL model are also optimal in this setting. © 2009 Elsevier B.V. All rights reserved

The versatility of a truss mounted mobile transporter for in-space construction

The Mobile Transporter (MT) evolution from early erectable structures assembly activities is detailed. The MT operational features which are required to support astronauts performing on-orbit structure construction or spacecraft assembly functions are presented and discussed. Use of the MT to perform a variety of assembly functions is presented. Estimated EVA assembly times for a precision segmented reflector approximately 20 m in diameter are presented. The EVA/MT technique under study for construction of the reflector (and the entire spacecraft) is illustrated. Finally, the current status of development activities and test results involving the MT and Space Station structural assembly are presented

NMR and LDA evidence for spiral magnetic order in the chain cuprate LiCu2O2

We report on {6,7}Li nuclear magnetic resonance measurements of the spin-chain compound LiCu2O2 in the paramagnetic and magnetically ordered states. Below T about 24 K the NMR lineshape presents a clear signature of incommensurate (IC) static modulation of the local magnetic field consistent with an IC spiral modulation of the magnetic moments. {7}Li NMR reveals strong phason-like dynamical fluctuations extending well below 24 K. We hypothesize that a series of phase transitions at 24.2, 22.5, and 9 K reflects a "Devil's staircase" type behavior generic for IC systems. LDA based calculations of exchange integrals reveal a large in-chain frustration leading to a magnetical spiral.Comment: 4 pages, 4 figure

Magnetic phase diagram of the frustrated S=1/2 chain magnet LiCu_2O_2

We present the results of the magnetization and dielectric constant measurements on untwinned single crystal samples of the frustrated S=1/2 chain cuprate LiCu_2O_2. Novel magnetic phase transitions were observed. A spin flop transition of the spiral spin plane was observed for the field orientations H||a,b. The second magnetic transition was observed at H~15 T for all three principal field directions. This high field magnetic phase is discussed as a collinear spin-modulated phase which is expected for an S=1/2 nearest-neighbor ferromagnetic and next-nearest-neighbor antiferromagnetic chain system

Are science students ready for university mathematics?

At UTS students in science courses often struggle with the first year first semester mathematics subject. This year we requested all commencing science students to take a Readiness Survey so that we could advise them of suitable pathways for the maths subjects in their degree. One such pathway includes taking a one-semester subject of introductory calculus before the regular mathematics subject. This paper reports on the practicalities of running such a test before semester starts, and the pathways taken up with varying levels of success by Science students. Insights from a parallel survey and pathway used for some years now with Engineering students in the same institution are offered

The Effects of Exposure to Endophyte-Infected Tall Fescue Seed on Faecal and Urine Concentrations of Ergovaline and Lysergic Acid in Mature Gelding Horses

Despite the good nutritive value of endophyte-infected tall fescue, consumption by livestock results in a decrease in both reproductive and growth performance due to ergot alkaloids produced by an endophytic fungus (Cross et al., 1995). Little research has investigated the metabolic fate of ergot alkaloids and/or their metabolites in grazing horses. Thus, the objectives of this experiment were: a) to determine concentrations of ergovaline (EV) and lysergic acid (LA) in the faeces and urine of geldings exposed to tall fescue seed over a time course experiment and b) to measure the effects of alkaloid-containing tall fescue on nutrient digestibility and serum clinical enzyme profiles

An Evaluation of Spirituality among Graduate and Professional Degree Students: Year Two

[Note: This is a continuation of a study that was introduced at the 2013 GERA Annual Meeting.] This ongoing longitudinal study is designed to measure spirituality in graduate and professional degree students utilizing validated survey instruments. Furthermore, the study investigates perceptions regarding the role of spirituality in higher education and professional practice. We hypothesize that significant relationships exist between student perceptions on spirituality and various academic, professional, and vocational outcomes. The study is being conducted at a large, private university in the southeastern United States, which seeks to enrich both the mind and spirit of students while maintaining intellectual and religious freedom. Our study measures spirituality from inter-faith and non-faith perspectives, thereby increasing applicability to a diverse population. Results from our study will be instrumental in examining the influence of an academic institution on validated measures of spirituality. Furthermore, we hope to be the first to examine, from a qualitative and quantitative perspective, the change in daily spiritual experience among students of diverse graduate and professional degree programs at a single institution. We believe our findings have the potential to stimulate constructive dialogue on the imperative to develop methods for improved teaching and learning

Partner Interfering Behaviors Affecting Cancer Quality of Life

Objective: Because partners are an important and unpaid resource in cancer care, understanding how destructive, controlling or interfering partner behaviors influence women\u27s cancer care may be particularly relevant for health care providers seeking to provide cancer care and enhance recovery. Using a new measure of partner interfering behaviors in cancer care (PIB-C), we investigated whether women with a recent cancer diagnosis who additionally endorsed any PIB-C would report (a) more symptoms of depression and stress, and (b) lower Functional Assessment of Cancer Therapy (FACT-G) and lower Functional Assessment of Chronic Illness Therapy-Spiritual Well-being (FACIT-SP) scale scores indicating poorer quality of life (QOL). Methods: Women aged 18–79 included in cancer registries as having an incident, primary, biopsy-confirmed cancer in the past 12 months were eligible for this study. Consenting women completed a phone interview 9–12 months following cancer diagnosis between 2009 and 2015. Interviews provided data to measure outcomes (perceived stress and depressive symptoms, FACIT-SP and FACT-G scores), partner supportive and interfering behaviors, and other potentially confounding factors. Results: Of the 2376 women in a relationship at cancer diagnosis, 14.7% endorsed one or more of 14 PIB-C items. Women endorsing any PIB-C item reported more symptoms of depression and stress and lower FACT-G and FACIT-SP scores than partnered women reporting no PIB-C even when controlling for partner supportive behaviors and lifetime intimate partner violence. Increasing PIB-C scores were also correlated, in a dose–response pattern, with these same outcomes. Conclusions: Partner interfering behaviors during cancer care impact patients\u27 QOL across multiple domains

Tests of an alternate mobile transporter and extravehicular activity assembly procedure for the Space Station Freedom truss

Results are presented from a ground test program of an alternate mobile transporter (MT) concept and extravehicular activity (EVA) assembly procedure for the Space Station Freedom (SSF) truss keel. A three-bay orthogonal tetrahedral truss beam consisting of 44 2-in-diameter struts and 16 nodes was assembled repeatedly in neutral buoyancy by pairs of pressure-suited test subjects working from astronaut positioning devices (APD's) on the MT. The truss bays were cubic with edges 15 ft long. All the truss joint hardware was found to be EVA compatible. The average unit assembly time for a single pair of experienced test subjects was 27.6 sec/strut, which is about half the time derived from other SSF truss assembly tests. A concept for integration of utility trays during truss assembly is introduced and demonstrated in the assembly tests. The concept, which requires minimal EVA handling of the trays, is shown to have little impact on overall assembly time. The results of these tests indicate that by using an MT equipped with APD's, rapid EVA assembly of a space station-size truss structure can be expected