Approximate Model Spaces for Model-Robust Experiment Design

Optimal designs depend upon a prespecified model form. A popular and effective model-robust alternative is to design with respect to a set of models instead of just one. However, model spaces associated with experiments of interest are often prohibitively large and so algorithmically generated designs are infeasible. Here, we present a simple method that largely eliminates this problem by choosing a small set of models that approximates the full set and finding designs that are explicitly robust for this small set. We build our procedure on a restricted columnwise-pairwise algorithm, and explore its effectiveness for two model spaces in the literature. For smaller full model spaces, we find that the designs constructed with the new method compare favorably with robust designs that use the full model space, with construction times reduced by orders of magnitude. We also construct designs that heretofore have been unobtainable due to the size of their model spaces. Supplementary material (available online) includes code, designs, and additional results.     

Reactivity studies of 2,3,5,6-Tetra(2-pyridyl) pyrazine (tppz) with first-row transition metal ions

Reactions of 2,3,5,6-tetra(2-pyridyl) pyrazine (tppz) with [ML₆][X]₂ (L = CH₃CN, H₂O;X = [BF₄]⁻, [ClO₄]⁻, [NO₃]⁻ [BArF]⁻(BArF - B[3,5-C₆H₃(CF₃)₂]₄) lead to the high-yield formation of mononuclear [M(tppz)₂]²⁺, (M = Mn^II, Fe^II, Co^II, and Ni^II) and dinuclear [Ni₂(tppz)(CH₃CN)₆]⁴⁺ species. The new compounds were fully characterized by X-ray crystallographic, spectroscopic, and magnetic susceptibility measurements. Surprisingly, the 2:1 M:tppz reactions did not lead to isolation of the dinuclear species except in the case of Ni(II). It was further noted that even in the case of the Ni reactions, the nuclearity of the product depends on the choice of anions and the reaction conditions. Magnetic measurements of the mononuclear species [Co(tppz)₂]²⁺ revealed thermally induced spin-crossover behavior from a high-spin S = 3/2 at higher temperatures to a low-spin S = 1/2 complex at lower temperatures. The dinuclear compound [Ni₂(tppz)(CH₃CN)₆]⁴⁺ exhibits a weak anti-ferromagnetic interaction through the bridging tppz ligand.     

Michael J. Mahoney (1946-2006).

Presents an obituary for Micheal J. Mahoney. Mahoney made immeasurable contributions to the field of psychology as an influential researcher, a prolific writer, and an innovative pioneer in bringing constructivist philosophy into psychotherapy. A deep thinker, a revolutionary-spirited theorist, and a passionate philosopher, Michael challenged the dominant paradigms of behavioral and cognitive psychology, inspiring psychologists to consider ever more complex models of human experience, to think in a more interdisciplinary way, and to relate more compassionately to the inevitable human experiences of suffering and change. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Alcohol Consumption Moderates the Link Between Cannabis Use and Cannabis Dependence in an Internet Survey.

The link between cannabis use and cannabis dependence remains poorly understood. Some people use cannabis regularly without signs of dependence; others show dependence despite using less. This study examined alcohol consumption as a moderator of this association. A sample of 476 people (primarily Caucasian men) who used cannabis at least once per week reported their alcohol consumption, cannabis use, and cannabis dependence symptoms in an Internet survey. Regressions revealed significant interactions between measures of cannabis use and alcohol consumption when predicting cannabis dependence. Cannabis use covaried with cannabis dependence, particularly in people who consumed alcohol frequently or in large amounts per week. Despite limitations, these data suggest that alcohol may decrease the safety of cannabis consumption. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Nursing, healing and spirituality

The premise of this article is that nurses are healers, primarily through the caring relationships they form with patients. Caring calls out an individual's inner strengths. These strengths include spiritual resources which support integration or wholeness of body, mind and spirit. Many nurses are unsure about giving spiritual care. This author encourages nurses to reflect on their own spirituality and learn spiritual care skills. By addressing the spiritual dimension in patient care, nurses can truly be holistic practitioners and positively affect the mental and physical health of their patients.     

Stability of Older Adults' Preferences for Life-Sustaining Medical Treatment.

The use of instructional advance directives assumes that preferences for life-sustaining medical treatment remain stable over time and across changes in life condition. A sample of 332 older adults recorded their preferences for 4 life-sustaining treatments in 9 illness scenarios. These preferences were elicited again 1 and 2 years after the original interview. Overall, preferences for life-sustaining treatment were moderately stable over time, but stability varied significantly across judgments. Preferences were most stable for illness scenarios that were most and least serious and for decisions to refuse treatment. Age, gender, education, and prior completion of an advance directive were all related to preference stability, and evidence indicated that declines in physical or psychological functioning resulted in decreased interest in life-sustaining treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Factor analysis of the Children's Depression Inventory in a community sample.

The factor structure of the Children's Depression Inventory (CDI; M. Kovacs, 1992) was evaluated in a large community sample of 1,777 children and 924 adolescents. There were 5 first-order factors (Externalizing, Dysphoria, Self-Deprecation, School Problems, and Social Problems) for the child group; the adolescent group yielded the same 5 factors plus a 6th factor (Biological Dysregulation). Confirmatory factor analyses supported the stability and replicability of the obtained factor structures. Both samples yielded 2 higher order factors—Internalizing and Externalizing. The factors were compared with previous CDI factors identified for clinical (B. Weiss et al., 1991) and community (M. Kovacs, 1992) samples. Other notable findings included more boys reporting high scores (17 and above) on the CDI among the child sample, whereas, among adolescents more girls reported high scores (17 and above) on the total CDI as well as higher scores on the biological dysregulation factor. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fates worse than death: The role of valued life activities in health-state evaluations.

One hundred eight college students (Study 1) and 109 elderly adults (Study 2) rated 28 health impairments for the quality of life perceived to be possible in that state, the extent to which the state was perceived as a fate better or worse than death, and the extent to which the state was perceived to interfere with the ability to engage in the activities each individual valued most in life. States perceived most negatively were those perceived to interfere most with valued life activities. For any given health state, evaluations were more negative the more the state was perceived by individuals as likely to interfere with engagement in their valued life activities. Implications of these results for end-of-life medical decision making in general and the use of advance medical directives in particular are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Scheduling unrelated parallel machines with sequence-dependent setups

A methodology for minimizing the weighted tardiness of jobs in unrelated parallel machining scheduling with sequence-dependent setups is presented in this paper. To comply with industrial situations, the dynamic release of jobs and dynamic availability of machines are assumed. Recognizing the inherent difficulty in solving industrial-size problems efficiently, six different search algorithms based on tabu search are developed to identify the best schedule that gives the minimum weighted tardiness. To enhance both the efficiency and efficacy of the search algorithms, four different initial solution finding mechanisms, based on dispatching rules, are developed. While there is no evidence of identifying solutions of better quality by employing a specific initial solution finding mechanism, the use of a specific search algorithm led to identifying solutions of better quality or that required lower computation time, but not both. Based on the extensive statistical analysis performed, the search algorithm with short-term memory and fixed tabu list size is recommended for solving small size problems, while that with long-term memory and minimum frequency for solving medium and large size problems, combined with fixed tabu list size for the former and variable tabu list size for the latter.     

Ergonomic evaluation of the ambulance interior to reduce paramedic discomfort and posture stress

OBJECTIVE: This study aims to evaluate safety and accessibility of an advanced life support (ALS) ambulance interior. BACKGROUND: The standard ambulance's interior design is unsatisfactory based on perceived discomfort and postures that constrain paramedics and medical staff, resulting in unsafe treatment of patients, mainly when being transported. METHODS: Two procedures were used to evaluate performance during a wide range of rescue tasks: a survey, based on questionnaires, interviews, and observation of paramedics performing routine tasks; and upper body and back posture analysis, based on postural considerations. RESULTS: Findings revealed that 74% of the paramedics stated that the location of the paramedic's seat is inefficient while they perform clinical procedures; 94% found the bench uncomfortable; 77% felt that the vertical distance between the bench and the stretcher is too far; and 86% needed to steady themselves when the vehicle was moving. Posture analysis showed that paramedics undergo several nonneutral back postures, including twisted back (>20 degrees) and sitting with back flexion between 20 degrees and 45 degrees. CONCLUSION: Because the interior of the ALS ambulance was found to be unsatisfactory both to paramedics and patients, alternative design issues are proposed. APPLICATION: The suggested practical layout contains four main modifications: (a) replacing the bench with two adjustable paramedic seats, (b) redesigning the medical cabinet for easy access, (c) adding an adjustable folding seat opposite the two new seats, and (d) adding a swiveling base and lifting apparatus that will accommodate the stretcher and enable better accessibility to patients by the paramedic personnel.