Longitudinal dynamic analyses of cognition in the health and retirement study panel

The purpose of this paper is to highlight some classic issues in the measurement of change and to show how contemporary solutions can be used to deal with some of these issues. Five classic issues will be raised here: (1) Separating individual changes from group differences; (2) options for incomplete longitudinal data over time, (3) options for nonlinear changes over time; (4) measurement invariance in studies of changes over time; and (5) new opportunities for modeling dynamic changes. For each issue we will describe the problem, and then review some contemporary solutions to these problems base on Structural Equation Models (SEM). We will fit these SEM to using existing panel data from the Health & Retirement Study (HRS) cognitive variables. This is not intended as an overly technical treatment, so only a few basic equations are presented, examples will be displayed graphically, and more complete references to the contemporary solutions will be given throughout.     

Vendor Selection with Bundling: A Comment*

In a recent article by Rosenthal, Zydiak, and Chaudhry (1995), a mixed integer linear programming model was introduced to solve the vendor selection problem for the case in which the vendor can sell items individually or as part of a bundle. Each vendor offered only one type of bundle, and the buyer could purchase at most one bundle per vendor. The model employed n(m+ 1) binary variables, where n is the number of vendors and m is the number of products they sell. The existing model can lead to a purchasing paradox: it may force the buyer to pay more to receive less. We suggest a reformulation of the same problem that (i) eliminates this paradox and reveals a more cost-effective purchasing strategy; (ii) uses only n integer variables and significantly reduces the computational workload; and (iii) permits the buyer to purchase more than one bundle per vendor.     

Sociology's misfortune: disciplines, interdisciplinarity and the impact of audit culture

This paper is about tendencies to the subversion of sociology as a discipline. It connects external factors of the wider socio-political environment of higher education in the UK, especially those associated with the audit culture and new systems of governance, with the internal organization of the discipline. While the environment is similar for all social science subjects, the paper argues that there are specific consequences for sociology because of characteristics peculiar to the discipline. The paper discusses these consequences in terms of the changing relationship between sociology and the growing interdisciplinary area of applied social studies as a form of 'mode 2 knowledge'. It argues that while sociology 'exports' concepts, methodologies and personnel it lacks the internal disciplinary integrity of other 'exporter' disciplines, such as economics, political science and anthropology. The consequence is an increasingly blurred distinction between sociology as a discipline and the interdisciplinary area of applied social studies with a potential loss of disciplinary identity. The paper concludes with a discussion of how this loss of identity is associated with a reduced ability to reproduce a critical sensibility within sociology and absorption to the constraints of audit culture with its preferred form of mode 2 knowledge.     

Implementing integrated pest management in professional lawn care: a case study

Human choices regarding land cover management practices may influence ecosystem services provided by urban green spaces. We conducted a 2-year study to compare biological (weed, insect, and disease), aesthetic (lawn quality), and economic (lawn care program cost) attributes of an integrated pest management (IPM) program, in which pesticides are applied on the basis of treatment thresholds, with a standard program, in which pesticides are applied on a calendar basis without pest monitoring. Both programs were managed by a professional lawn care operator. Although weed incidence was low, the IPM program had significantly more lawns with weed presence than the standard program during 2005 and 2006. However, only 21% of the IPM lawns required herbicide applications in 2005, and none exceeded the treatment threshold (5% weed cover) in 2006 as compared to 100% of the standard program lawns being treated for weeds in both years. The IPM program also had significantly more lawns with insect damage than the standard program during June 2005 and August 2005, but not September 2005 and throughout 2006. Only 28% of the IPM lawns required insecticide applications in 2005 and none exceeded the threshold (5% insect damage) in 2006 whereas all of the lawns in the standard program received insecticide treatments in both years. Rhizoctonia blight was present on some of the lawns, but was not a common problem. Although lawn quality was high for both programs (>8, on a scale of 1–9), it was significantly higher for standard than for IPM program lawns during 2005, and June 2006 and September 2006, but not August 2006. The annual lawn management costs were lower for the IPM (281.50) than the standard program (281.50) than the standard program (458.06). Thirty one percent of the IPM program customers who continued with the study in 2006 did so because they were satisfied with the IPM program. Among those who did not continue with the program, 33% cited weed or insect problems, while 33% expected better results. The implications of these findings for implementation of IPM in professional lawn care are further discussed.     

The potential value of mosses for stormwater management in urban environments

Plant-based stormwater management systems such as green roofs are typically composed exclusively of vascular plants. Yet, mosses have several desirable properties that could warrant their more widespread use in green roof applications. In natural systems mosses are important primary colonizers of bare ground, and their establishment improves water storage and provides numerous soil benefits including carbon and nitrogen sequestration. Additionally, mosses often facilitate the establishment and survival of vascular plants at otherwise environmentally harsh or stressful sites. Despite their potential value, few studies have investigated the functional performance of mosses on green roofs. In this study we evaluated the establishment success and potential stormwater performance of three candidate moss species. We also directly compared the runoff and thermal characteristics of replicate moss covered green roofs to vascular planted and bare roofs. Candidate mosses had high water holding capacities, storing 8–10 times their weight in water compared to only 1.3 times for typical green roof medium. Mock-up roof sections composed of mosses and medium had delayed and reduced runoff flows relative to medium only sections, although the magnitude of these effects varied with moss species. In field trials all three mosses survived a harsh rooftop environment with limited summer irrigation, although lateral growth after one year was minimal. Green roofs planted solely with Racomitrium canescens had between 12–24% higher stormwater retention than vascular or medium only roofs. Moss cover also ameliorated temperature fluctuations on green roofs. Hourly heating rates were buffered to a similar degree (less than half that of surface temperatures) 5 cm below the surface of both moss covered and medium only roofs. In contrast, cooling under the surface of the moss roof was nearly 6 times faster than under the medium only roof. These results demonstrate the potential for mosses to be valuable components of green roofs, either in combination with vascular plants or planted exclusively.     

The big story about small stories: Narratives of crime and terrorism

The ‘big story/small story’ distinction has emerged as a discrete approach to narrative analysis. Proponents of this approach are critical of the ‘big stories’ elicited by structural analysts, which they see as highly structured narratives of past experiences, typically elicited in an interview context. In contrast, they highlight the importance of studying the fragmented, contextualised ‘small stories’ that arise in everyday conversation/interaction. We question the basis of this distinction and we suggest that it unnecessarily proliferates analytic categories. Further, we suggest that the methodologies followed by ‘small stories’ analysts are often similar to those used to elicit ‘big stories’ and are hence open to similar criticisms; in particular, a failure to fully consider the issue of (contextual) naturalism. Drawing on interviews of crime/terrorism in Northern Ireland, we show how these data comprise both ‘big stories’ and ‘small stories’ within the same context and often within the same narrative.     

One Decade of Self Exclusion: Missouri Casino Self-Excluders Four to Ten Years after Enrollment

For more than a decade, casinos around the world have offered self-exclusion programs (SEPs) to gamblers seeking help with their gambling behavior. Despite the proliferation of SEPs, little is known about the long-term outcomes for gamblers who utilize these programs. The current study assessed the experiences of a sample (N = 113) of Missouri self-excluders (SEs) for as long as 10 years after their initial enrollment in the Missouri Voluntary Exclusion Program (MVEP). Most SEs had positive experiences with MVEP and reduced their gambling and gambling problems after enrollment. However, 50% of SEs who attempted to trespass at Missouri casinos after enrollment were able to, indicating that the benefit of MVEP was attributable more to the act of enrollment than enforcement. SEs who engaged in complementary treatment or self-help groups had more positive outcomes than those who did not, suggesting that SEPs ought to encourage and provide information about additional support and treatment options to participants.