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Although microviruses do not possess a visible tail structure, one vertex rearranges after interacting with host lipopolysaccharides. Most examinations of host range, eclipse, and penetration were conducted before this “host-induced” unique vertex was discovered and before DNA sequencing became routine. Consequently, structure-function relationships dictating host range remain undefined. Biochemical and genetic analyses were conducted with two closely related microviruses, α3 and ST-1. Despite ∼90% amino acid identity, the natural host of α3 is Escherichia coli C, whereas ST-1 is a K-12-specific phage. Virions attached and eclipsed to both native and unsusceptible hosts; however, they breached only the native host’s cell wall. This suggests that unsusceptible host-phage interactions promote off-pathway reactions that can inactivate viruses without penetration. This phenomenon may have broader ecological implications. To determine which structural proteins conferred host range specificity, chimeric virions were generated by individually interchanging the coat, spike, or DNA pilot proteins. Interchanging the coat protein switched host range. However, host range expansion could be conferred by single point mutations in the coat protein. The expansion phenotype was recessive: genetically mutant progeny from coinfected cells did not display the phenotype. Thus, mutant isolation required populations generated in environments with low multiplicities of infection (MOI), a phenomenon that may have impacted past host range studies in both prokaryotic and eukaryotic systems. The resulting genetic and structural data were consistent enough that host range expansion could be predicted, broadening the classical definition of antireceptors to include interfaces between protein complexes within the capsid. IMPORTANCE To expand host range, viruses must interact with unsusceptible host cell surfaces, which could be detrimental. As observed in this study, virions were inactivated without genome penetration. This may be advantageous to potential new hosts, culling the viral population from which an expanded host range mutant could emerge. When identified, altered host range mutations were recessive. Accordingly, isolation required populations generated in low-MOI environments. However, in laboratory settings, viral propagation includes high-MOI conditions. Typically, infected cultures incubate until all cells produce progeny. Thus, coinfections dominate later replication cycles, masking recessive host range expansion phenotypes. This may have impacted similar studies with other viruses. Last, structural and genetic data could be used to predict site-directed mutant phenotypes, which may broaden the classic antireceptor definition to include interfaces between capsid complexes.

In educational and psychological tests, 2 forms of bias have been distinguished: internal and external (or predictive) bias. However, the relation between internal and external test bias has not be...

This study investigated effects of retaining test items manifesting differential item functioning (DIF) on aspects of the measurement quality and validity of that test’s scores. DIF was evaluated using the Mantel-Haenszel procedure, which allows one to detect items that function differently in two groups of examinees at constant levels of the trait. Multiple composites of DIF-and non-DIF-containing items were created to examine the impact of DIF on the measurement, validity, and predictive relations involving those composites. Criteria used were the American College Testing composite, the Scholastic Aptitude Test (SAT) verbal (SATV), quantitative (SATQ), composite (SATC), and grade point average rank percentile. Results indicate measurement quality of tests is not seriously degraded when items manifesting DIF are retained, even when number of items in the compared composites has been controlled. Implications of results are discussed within the framework of multiple determinants of item responses.

Two studies were conducted to examine some issues regarding the influence of dispositional negative affectivity (Watson & Clark, 1984; Clark & Watson, 1991) on task/job satisfaction and self-reported employee behaviors, as well as the cognitive processes underlying these relationships. In Study 1, data were collected from 165 individuals representing a variety of jobs in four organizations. Data from a second study were obtained in a laboratory setting from 150 subjects who performed either an "enriched" or an "unenriched" task. Results indicate that: (1) negative affectivity is a significant predictor of satisfaction unless task conditions are quite aversive, (2) individuals with higher negative affectivity report performing a greater frequency of withdrawal behaviors than individuals with lower negative affectivity when both dissatisfied and satisfied with their jobs, and (3) individuals higher in negative affectivity recall the negative features of tasks while individuals lower in negative affectivity recall more descriptive aspects of tasks. We suggest that future research focus on the nature of the dispositional affectivity construct and on the cognitive processes underlying the linkages among dispositions, attitudes, and behaviors.

A Monte Carlo investigation of simplex fitting as a method of determining the dimensionality of binary data matrices was carried out. The simplex is an index of dimensionality having considerable appeal on a priori grounds. The study was carried out to explore the adequacy of simplex fitting for estimating dimensionality of binary item pools. To achieve this objective, an examination was made of the fit of correlation matrices with known factor structure to a correlation matrix representing a perfect simplex. Results indicated that the simplex fitting method is a viable approach to dimensionality assessment under certain situations. However, simplex fitting breaks down under extreme values of two important parameters. At less extreme levels of these parameters, the simplex fitting method is more effective than are the usual factor analytic dimensionality criteria. Results are discussed within the realm of considering the tenability of the goal of strict unidimensionality and the consequences of failure to assess correctly the dimensionality of a data matrix. The importance of attempting to measure major or dominant factors is also described. Finally, the need for examining whether current methods fail under similar conditions and suggestions for future research involving simplex fitting are discussed.

This study investigated several current coaching practices used in training test-wiseness for analogy items in standardized test batteries. A three-group design was used which included a general test-taking, "encouragement" condition in addition to a no-training control group condition. The specific techniques used in training are described. Scholastic Aptitude Test (SAT) scores were obtained from university admission files to verify that no overall aptitude differences existed in the three conditions. Differences were observed for the coached group relative to the two control groups in terms of overall number of correct responses for the coached item types (analogies). No differences were found for the non-coached item types. Item difficulties for the three groups are also reported which show that several items were indeed made easier for individuals in the coached group. A qualitative analysis of the items made easier by coaching in terms of the training techniques used is given along with an analysis o...

In applications of covariance structure modeling in which an initial model does not fit sample data well, it has become common practice to modify that model to improve its fit. Because this process is data driven, it is inherently susceptible to capitalization on chance characteristics of the data, thus raising the question of whether model modifications generalize to other samples or to the population. This issue is discussed in detail and is explored empirically through sampling studies using 2 large sets of data. Results demonstrate that over repeated samples, model modifications may be very inconsistent and cross-validation results may behave erratically. These findings lead to skepticism about generalizability of models resulting from data-driven modifications of an initial model. The use of alternative a priori models is recommended as a preferred strategy.

In this chapter we will examine choosing a show; creating the premise; overcoming challenges; analyzing the script; assessing the collaborators; exploring personal history; expanding the vision; and communicating the premise.

For designers and directors alike, the entire production revolves around one collaborator who rarely attends production meetings: the playwright. You have heard it before but, honestly, it all begins and ends with the script: the common ground from which we all create. The deciding factor in most debates and the duty of any member of the production team is to serve the script. The sole reason for everyone devoting the time and effort to any production revolves around the script—or more correctly, around the production team’s interpretation of the script.

Thoroughly researching a play is impossible. There are always details you cannot even begin to tackle. Beside the imminent demand of production schedules, there are just too many elements that must be addressed. Even if you are lucky enough to have the assistance of a dramaturg, you can never cover everything.

A discussion and an investigation of the benefits of creating correspondence between general attitude and multifaceted behavior measures as an antidote to narrowing attitude assessments to match the specificity of narrow, isolated behaviors are conducted. We investigate these issues specifically in the realm of job satisfaction and employee adaptation and withdrawal. Results from several samples are presented that show the advantages of building systematic heterogeneity into both attitude and behavioral measures as recommended by attitude theorists. Implications for research in the areas of social and work attitudes are discussed.

Introduction Victims of intimate partner violence against women (IPVAW) often come into contact with various health care professionals, including emergency nurses. Michigan has implemented an ED surveillance system to monitor IPVAW in the state. Methods Twenty-three emergency departments participate in the Michigan Intimate Partner Violence Surveillance System. Female assault and maltreatment victims are identified using International Classification of Diseases Clinical Modification (ICD-9-CM) diagnostic and E codes (External Cause of Injury/Adverse Effects codes). For a 2-year period (1999-2000), patients' charts were reviewed, usually by an emergency nurse, to identify IPVAW victims. Results A total of 3111 female assault and maltreatment victims were identified. Of the 2926 incidents for which physical and/or sexual violence was confirmed by chart review, 1136 (38.8% [95% confidence interval: 37.1% to 40.6%]) involved IPVAW. Discussion A hospital ED surveillance system revealed that more than a third of female assault and maltreatment incidents were attributable to intimate partner violence, with a considerable proportion being young women abused by an ex-boyfriend. Surveillance also identified a need for improved documentation of female assault and maltreatment in ED records. We realized the benefits of using a public health surveillance process to monitor IPVAW incidence, identify high-risk groups, and reduce research costs.

Theoretical arguments and analyses from 2 studies provide compelling evidence that computerized measures of information-processing skills and abilities are highly useful supplements to more traditional, paper-based measures of general mental ability for predicting individuals' capacity to learn from and perform on highly challenging, multifaceted tutors. These tutors were designed to emulate learning and performance in complex, real-world settings. Hierarchical confirmatory factor analysis provided evidence that a general, higher order factor model with general ability at the apex could quite adequately and singularly account for the individual-differences data, both traditional and cognitive-process measures. Results are interpreted in light of the utility and generality of human cognitive abilities.