Random effects analysis
This paper explores relationships among environmental attitudes, nonuse values for endangered species, and underlying motivations for contingent valuation (CV) responses. The approach combines techniques from the attitude–behavior and economic valuation literature. Attitudes are measured with the New Ecological Paradigm (NEP) scale, and economic values are derived from a referendum, CV survey for peregrine falcons and shortnose sturgeons. Respondents with stronger pro-environmental attitudes are found more likely to provide legitimate yes/no responses, while those with weaker attitudes are more likely to protest hypothetical CV scenarios. Analysis reveals environmental attitudes as a significant explanatory variable of yes/no responses, whereby stronger pro-environmental attitudes result in higher probabilities of responding ‘yes’. Pro-environmental attitudes are also shown to result in higher estimates of mean willingness to pay (WTP). Significant relationships are found between environmental attitudes and nonuse motivations. Specifically, pro-environmental attitudes are associated with stronger reliance on ethical motives for species protection. These results are discussed as they relate to testing predictions in the literature about potential bias in CV studies and to supporting National Oceanic and Atmospheric Administration (NOAA) recommendations for improving CV reliability.
The validity of a simple statistical model for estimating fluvial constituent loads: An Empirical study involving nutrient loads entering Chesapeake Bay
We consider the appropriateness of “rating curves” and other log linear models to estimate the fluvial transport of nutrients. Split-sample studies using data from tributaries to the Chesapeake Bay reveal that a minimum variance unbiased estimator (MVUE), based on a simple log linear model, provides satisfactory load estimates, even in some cases where the model exhibited significant lack of fit. For total nitrogen (TN) the average difference between the MVUE estimates and the observed loads ranges from −8% to + 2% at the four sites. The corresponding range for total phosphorus (TP) is −6% to +5%. None of these differences is statistically significant. The observed variability of the MVUE load estimates for TN and TP, which ranges from 7% to 25% depending on the case, is accurately predicted by statistical theory.
Valuing wildlife in benefit‐cost analyses: A case study involving endangered species
The focus of the research presented in this paper is to ask what types of values are relevant in the valuation of wildlife species for benefit-cost analyses of projects that may affect wildlife or its habitat. First, the components of value for wildlife resources are discussed, with emphasis on those particularly relevant to the valuation of endangered species. A simple model is then proposed and results from an application to valuing two of Wisconsin's endangered species of wildlife are presented. The empirical results indicate that significant values may be associated with endangered species of wildlife above and beyond those that arise from viewing these species in the wild. We conclude that to overlook values for wildlife species that go beyond common use values may result in a misleading project or policy decision.
Utilization of Contextual Information in Determining the Meaning of Unfamiliar Words.
TWO STUDIES were conducted to evaluate students' ability to utilize contextual information in learning the meaning of unfamiliar words. A descriptive study involving fourth-, fifth-, and sixth-grade children was designed to examine the differential effects of form and proximity of contextual information on students'learning of unfamiliar words. An experimental study involving the same-aged students was conducted to examine the differential effects of three intervention strategies designed to facilitate the use of contextual information in learning the meanings of unfamiliar words. The results of the descriptive study suggest that students were better able to determine the meaning of unfamiliar words when (a) contextual clues were provided, (b) students were older, (c) the clues were in synonym rather than inference form, and (d) contextual clues were closer to the unfamiliar word. In the experimental study, rule-plus-systematic-practice and systematic-practice-only conditions produced higher transfer scores than a nointervention condition.
Software error analysis: a real case study involving real faults and mutations
The paper reports on a first experimental comparison of software errors generated by real faults and by 1st-order mutations. The experiments were conducted on a program developed by a student from the industrial specification of a critical software from the civil nuclear field. Emphasis was put on the analysis of errors produced upon activation of 12 real faults by focusing on the mechanisms of error creation, masking, and propagation up to failure occurrence, and on the comparison of these errors with those created by 24 mutations. The results involve a total of 3730 errors recorded from program execution traces: 1458 errors were produced by the real faults, and the 2272 others by the mutations. They are in favor of a suitable consistency between errors generated by mutations and by real faults: 85% of the 2272 errors due to the mutations were also produced by the real faults. Moreover, it was observed that although the studied mutations were simple faults, they can create erroneous behaviors as complex as those identified for the real faults. This lends support to the representativeness of errors due to mutations.
Using combined eye tracking and word association in order to assess novel packaging solutions: A case study involving jam jars
The present study utilized the techniques of eye tracking and word association in order to collect attentional information and freely-elicited associations from consumers in response to changing specific attributes of the product packaging (jam jars). We assessed the relationship between the data obtained from these two measures in a non goal-directed (or choice-based) task. Additionally, we addressed the question of which packaging attributes affected the consumers’ self-reported willingness to try the product. To relate how each element variation contributed to the focusing of participants’ attention on each area of interest to the immediate message that they conveyed and to the participants’ willingness to try, the rich mixed data obtained were analysed by means of conjoint analysis and multiple factor analysis. The results demonstrated that certain elements of the product packaging can be used to drive visual attention to one element or another; for instance, the ridged surface of certain jars contributed to spread the gaze; however, an important part of the associations that these formats elicited were related to the ridges or to unusualness of the packaging, suggesting that these “secondary” stimuli also captured attention. Though this case study does not provide direct guidelines for packaging design, it does shed light on the importance of knowing how to combine the appropriate design elements to predetermine consumers’ gaze patterns in order to convey the desired messaging on product packaging.
Knee hyaline cartilage evaluated with MR imaging: a cadaveric study involving multiple imaging sequences and intraarticular injection of gadolinium and saline solution.
Magnetic resonance (MR) imaging of cadaveric knees was performed to determine optimal sequences for visualization of hyaline cartilage. Six fresh-frozen cadaveric knees were imaged with a 1.5-T imager by means of standard and hybrid fat suppression (HFS) spin-echo techniques, with and without intraarticular injection of saline solution and gadopentetate dimeglumine. The knees then were sectioned at 4-mm intervals. Both the real and the imaged cartilage thicknesses were measured. Areas of cartilage thinning and focal defects seen in the cadaveric sections were most accurately matched, in both the presence and the absence of intraarticular saline solution simulating joint fluid, by images obtained with the T1-weighted HFS sequences. Accurate imaging of hyaline cartilage thickness with differentiation of cartilage from fluid was possible routinely. Standard and HFS spin-echo images obtained after intraarticular injection of gadopentetate dimeglumine depicted cartilage less accurately than HFS sequences either with or without saline injection. MR imaging with T1-weighted HFS sequences provided superior visualization of cartilage, enabling accurate measurements of cartilage thickness and differentiation of cartilage from saline solution simulating joint fluid.
Assessing genetic structure with multiple classes of molecular markers: a case study involving the introduced fire ant Solenopsis invicta.
We used 30 genetic markers of 6 different classes to describe hierarchical genetic structure in introduced populations of the fire ant Solenopsis invicta. These included four classes of presumably neutral nuclear loci (allozymes, codominant random amplified polymorphic DNAs (RAPDs), microsatellites, and dominant RAPDs), a class comprising two linked protein-coding nuclear loci under selection, and a marker of the mitochondrial DNA (mtDNA). Patterns of structure revealed by F statistics and exact tests of differentiation were highly concordant among the four classes of neutral nuclear markers, although the microsatellites were the most effective markers for detecting structure. The results from the mtDNA complemented those from the neutral nuclear markers by revealing that strong limitations to female-mediated gene flow were the cause of the local structure registered by the nuclear markers. The pattern of structure inferred from the selected nuclear loci was markedly different from the patterns derived from the other sets of markers but was predictable on the basis of the presumed mode of selection acting on these loci. In general, the results for all six classes of markers can be explained by known features of the social and reproductive biology of fire ants. Thus, the results from these diverse sets of markers, combined with detailed natural history data, provide an unusually complete picture of how the fundamental evolutionary forces of gene flow, drift, and selection govern the distribution of genetic variation within and between fire ant populations.
Volatile metabolites in the exhaled breath of healthy volunteers: their levels and distributions
The data obtained for the concentration distributions of the most abundant volatile metabolites in exhaled breath determined in two independent studies are reviewed, the first limited study involving five healthy volunteers providing daily breath samples over a month, and the subsequent study involving 30 healthy volunteers providing breath samples weekly over six months. Both studies were carried out using selected ion flow tube mass spectrometry, SIFT-MS, to obtain on-line, real-time analyses of single breath exhalations, avoiding the complications associated with sample collection. The distributions of the metabolites from the larger more comprehensive study are mostly seen to be log normal with the median values (in parts per billion, ppb) being ammonia (833), acetone (477), methanol (461), ethanol (112), propanol (18), acetaldehyde (22), isoprene (106) with the geometric standard deviation being typically 1.6, except for ethanol which was larger (3.24) due to the obvious increase of breath ethanol following the ingestion of sugar. These were the first well-defined concentration distributions of breath metabolites obtained and they are the essential requirement for recognizing abnormally high levels that are associated with particular diseases. The associations of each metabolite with known diseased states are alluded to. These SIFT-MS studies reveal the promise of breath analysis as a valuable addition to the tools for clinical diagnosis and therapeutic monitoring.
The effect of innovation on financial performance: A research study involving SMEs
Innovation has become a prime source for gaining a competitive edge in the market for all companies. This study seeks to investigate the effect of innovation of small and medium enterprises (SMEs) on their financial performance, as well as the effect of firm size on the impact of innovation. To examine empirically this relationship, data were collected via a survey of a sample of 98 SMEs belonging to the food machinery industry, and analyzed using a regression-based analysis. The empirical findings confirm that an increase in the innovation level increased financial performance. Specifically, they underline the relevance of the innovation developed in order to meet the customers’ needs as well as of those developed in order to differentiate from the competitors in improving the financial performance. Moreover, results suggest that in SMEs the level of technology adopted to develop innovation does not impact on the financial performance.
Where Do Neurologists Look When Viewing Brain CT Images? An Eye-Tracking Study Involving Stroke Cases
The aim of this study was to investigate where neurologists look when they view brain computed tomography (CT) images and to evaluate how they deploy their visual attention by comparing their gaze distribution with saliency maps. Brain CT images showing cerebrovascular accidents were presented to 12 neurologists and 12 control subjects. The subjects' ocular fixation positions were recorded using an eye-tracking device (Eyelink 1000). Heat maps were created based on the eye-fixation patterns of each group and compared between the two groups. The heat maps revealed that the areas on which control subjects frequently fixated often coincided with areas identified as outstanding in saliency maps, while the areas on which neurologists frequently fixated often did not. Dwell time in regions of interest (ROI) was likewise compared between the two groups, revealing that, although dwell time on large lesions was not different between the two groups, dwell time in clinically important areas with low salience was longer in neurologists than in controls. Therefore it appears that neurologists intentionally scan clinically important areas when reading brain CT images showing cerebrovascular accidents. Both neurologists and control subjects used the “bottom-up salience” form of visual attention, although the neurologists more effectively used the “top-down instruction” form.
Genetic and Phenotypic Heterogeneity in Disorders of Peroxisome Biogenesis—A Complementation Study Involving Cell Lines from 19 Patients
Disorders of peroxisomal biogenesis include the Zellweger syndrome, neonatal adrenoleukodystrophy, infantile Refsum syndrome, and hyperpipecolic acidemia. These names were assigned before the recognition of the peroxisomal defect and the distinction between phenotypes is uncertain. Recent studies have identified at least four complementation groups, and indicate the presence of at least that number of distinct genotypes. The purpose of the present study was to examine the relationship between genotype and phenotype. We studied cultured skin fibroblasts from 19 patients in whom deficiency of peroxisomes had been established. Complementation analysis was performed with the criterion of complementation being the restoration of the capacity to synthesize plasmalogens when fibroblasts from two patients were fused. Six complementation groups were identified, and consisted of one 13 member group, one two member group, and four groups comprising single cases. The phenotype of each group was examined with respect to age of survival, clinical manifestations, and biochemical alterations. The 13 member group included patients with all of the four currently designated phenotypic entities, while the most common phenotype (Zellweger syndrome) was distributed among five of the six groups. We conclude that the currently used clinical categories do not represent distinct genotypes. Apparently different genes code for a similar phenotype and one defective gene may lead to variant phenotypes. Definitive classification and understanding of these disorders await definition of the specific biochemical defect in each of the genotypes.
ESC/Java2: Uniting ESC/Java and JML Progress and Issues in Building and Using ESC/Java2, Including a Case Study Involving the Use of the Tool to Verify Portions of an Internet Voting Tally System
The ESC/Java tool was a lauded advance in effective static checking of realistic Java programs, but has become out-of-date with respect to Java and the Java Modeling Language (JML). The ESC/Java2 project, whose progress is described in this paper, builds on the final release of ESC/Java from DEC/SRC in several ways. It parses all of JML, thus can be used with the growing body of JML-annotated Java code; it has additional static checking capabilities; and it has been designed, constructed, and documented in such a way as to improve the tool's usability to both users and researchers. It is intended that ESC/Java2 be used for further research in, and larger-scale case studies of, annotation and verification, and for studies in programmer productivity that may result from its integration with other tools that work with JML and Java. The initial results of the first major use of ESC/Java2, that of the verification of parts of the tally subsystem of the Dutch Internet voting system are presented as well.
Quality, Impact and Success of ERP Systems: A Study Involving Some Firms in the Nordic-Baltic Region
Enterprise Resource Planning (ERP) systems are among the largest information technology (IT) investments made by firms. Such systems are diffusing rapidly in the Nordic-Baltic region of Europe. While studies discuss the diffusion of ERP in the region, few studies discuss their success in adopting firms. In this study, we explored the issue of ERP success by sampling the views of private firms in two countries in the region. We employed a three-phase research approach to enhance the validity of our findings. We found that the views of ERP success in an emerging economy (Estonia) and a developed economy (Finland) were similar, and the perception of the qualities and impacts of ERP were not unique to the region, rather they are comparable to those reported in the literature. In that regard, the informational quality of ERP was the highest rated (order of importance) dimension of success for firms in our sample, and organizational impact rated the lowest. Another notable observation in the study was that ERP success in adopting firms in the region might be related to the nature of ERP being acquired, namely, less complex systems may be providing higher success levels. The implications of the findings for both practice and research are highlighted and we outlined areas for future research.
A Multicenter Study Involving the Use of a Human Acellular Dermal Regenerative Tissue Matrix for the Treatment of Diabetic Lower Extremity Wounds
This multicenter, retrospective study presents the use of a human acellular dermal regenerative tissue matrix as an alternative treatment for 100 chronic, full-thickness wounds of the lower extremity in 75 diabetic patients. Comorbidities included cardiac disease (86.0%), neuropathy (86.0%), peripheral vascular disease (82.0%), infection (54.0%), obesity (51.0%), and osteomyelitis (37.0%). Wound locations included the foot (86.0%), ankle (8.0%), and lower extremity (6.0%). Mean wound age was 20.4 weeks (1.3-191.4 weeks). University of Texas (UT) wound classifications included 15 (15.0%) 1A, 1 (1.0%) 1B, 1 (1.0%) 1C, 2 (2.0%) 1D, 18 (18.0%) 2A, 8 (8.0%) 2B, 5 (5.0%) 2C, 3 (3.0%) 2D, 3 (3.0%) 3A, 7 (7.0%) 3B, 3 (3.0%) 3C, and 34 (34.0%) 3D. The mean time to matrix incorporation, 100% granulation, and complete healing was 1.5 weeks (0.43-4.4 weeks), 5.1 weeks (0.43-16.7 weeks), and 13.8 weeks (1.7-57.8 weeks), respectively. The overall matrix success rate, as defined by full epithelialization, was 90.0%. One failed wound subsequently healed approximately 7 weeks after matrix reapplication. The healing rate was 91.0%, as 91 of the 100 wounds healed. No statistically significant differences were observed between UT classifications and time to matrix incorporation, 100% granulation, and complete healing. Absence of matrix-related complications and high rates of closure in a wide array of diabetic wounds suggest that this matrix is a viable treatment for complex lower extremity wounds. Lack of any statistically significant differences between UT grades and wound outcome end points lends further support to the universal applicability of this matrix, with successful results in both superficial diabetic wounds and in wounds penetrating to the bone or joint.
Fitting mixtures of von Mises distributions: a case study involving sudden infant death syndrome
Sudden infant death syndrome (SIDS) exhibits a seasonal pattern with a winter peak. This pattern is not symmetric. It rises rapidly to a winter peak before falling more slowly to a dip in the summer. It has been suggested that the relatively flat peak may be due to the presence of more than one population, where each population corresponds to a different cause of SIDS. Various models based on the von Mises distribution are fitted to monthly data for England, Wales, Scotland and Northern Ireland for the years 1983-1998, including a single von Mises distribution, a mixture of a von Mises and a uniform distribution and a mixture of two von Mises distributions. There are a number of ways of fitting such models (Fisher, 1993; Spurr and Koutbeiy, 1991). Various computational problems arise with the fitting procedures. Attempts to tackle these problems for the SIDS data are discussed. A bootstrap likelihood ratio approach (Polymenis and Titterington, 1998) is used to assess how many components are required in the model. Its properties are investigated by simulation. The improvement in fit of two components compared to one is not significant in most years, and hence there is little evidence of two populations in the seasonality of SIDS. In most years, it was also impossible to fit a mixture of von Mises and uniform components, with a single von Mises distribution being sufficient.
A Collaborative Study to Establish the 2nd International Standard for Fibrinogen, Plasma
An International Collaborative Study involving 12 laboratories in 7 different countries was undertaken in order to replace the 1st International Standard (IS) for Fibrinogen, Plasma (89/644). The candidate replacement standard was the ampouled and freeze-dried residue of solvent/detergent treated plasma and was calibrated as coded duplicates (A and B) versus the 1st IS Fibrinogen, Plasma by automated Clauss assay and by a recommended clot collection (gravimetric) assay. This latter method had been used to calibrate the 1st IS Fibrinogen, Plasma. Comparing the ratios of the potency estimates of sample A to sample B (the coded duplicates), all of the laboratories obtained a ratio within 5% of the expected value of 1.0 by automated Clauss assay, which suggests that the laboratories were able to perform this assay well. Scrutiny of the data obtained from the gravimetric assays revealed that in almost all cases the results were invalid. The results of these assays are included in this report but clearly should be treated with caution and indeed produced significantly lower mean estimates of potency than the other assay methods. The overall geometric mean of all estimates of potency of the proposed 2nd IS Fibrinogen, Plasma (98/612) is 2.19 mg/ampoule by the automated Clauss assay. These data have been presented to the Fibrinogen Sub-Committee of the Standardisation and Scientific Committee (SSC) of the International Society on Thrombosis and Haemostasis (ISTH) (Washington, DC, August 1999), which recommended the establishment of 98/612 as the 2nd IS Fibrinogen, Plasma. This report has been presented to the Expert Committee on Biological Standardisation of the World Health Organisation (ECBS-WHO) at their 1999 session and 98/612 was established as the 2nd IS Fibrinogen, Plasma with a potency of 2.2 mg/ampoule.
Stroke in Relation to Cardiac Procedures in Patients With Non–ST-Elevation Acute Coronary Syndrome: A Study Involving >18 000 Patients
Background—There are few published data on risk factors for stroke in patients with non–ST-elevation acute coronary syndrome (ACS). We investigated prognostic factors for stroke in 2 large cohorts of patients from the Organization to Assess Strategies for Ischemic Syndromes (OASIS) registry (8010) and the OASIS-2 trial (10 141) Methods and Results—A total of 18 151 patients with non–ST-elevation ACS were enrolled in the OASIS program. Data from these 2 studies were pooled (a test for heterogeneity was nonsignificant, P =0.34). Overall, 238 patients (1.3%) had a stroke over a 6-month follow-up. Those who experienced stroke had a 4-fold increase in 6-month mortality (27.0% versus 6.3%, P <0.001). A Cox multivariate regression analysis identified CABG surgery as the most important predictor of stroke (hazard ratio [HR], 4.6), followed by history of stroke (HR, 2.3), diabetes mellitus (HR, 1.7), older age (HR, 1.6 per 10-year increase), higher heart rate (HR, 1.1 per 10-bpm increase), and on-site catheterization facility (HR, 1.4). There was no significant excess in stroke in patients undergoing percutaneous coronary intervention (P =0.21). Patients who underwent early CABG surgery were at a substantially increased risk compared with those who had later CABG (3.3% versus 1.6%; HR, 2.1;P =0.003) or who had no surgery (3.3% versus 1.1%; HR, 3.95;P =0.0001). Conclusions—In this large cohort of patients with ACS, stroke was an uncommon but serious event associated with high mortality. The performance of early CABG surgery was a powerful independent predictor of stroke.
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