Showing papers by "University of Kansas published in 2000"

Lower Extremity Function and Subsequent Disability Consistency Across Studies, Predictive Models, and Value of Gait Speed Alone Compared With the Short Physical Performance Battery

Abstract: Background. Although it has been demonstrated that physical performance measures predict incident disability in previously nondisabled older persons, the available data have not been fully developed to create usable methods for determining risk profiles in community-dwelling populations. Using several populations and different follow-up periods, this study replicates previous findings by using the Established Populations for the Epidemiologic Study of the Elderly (EPESE) performance battery and provides equations for the prediction of disability risk according to age, sex, and level of performance. Methods. Tests of balance, time to walk 8 ft, and time to rise from a chair 5 times were administered to 4,588 initially nondisabled persons in the four sites of the EPESE and to 1,946 initially nondisabled persons in the Hispanic EPESE. Follow-up assessment for activity of daily living (ADL) and mobility-related disability occurred from 1 to 6 years later. Results. In the EPESE, compared with those with the best performance (EPESE summary performance score of 10‐ 12), the relative risks of mobility-related disability for those with scores of 4‐6 ranged from 2.9 to 4.9 and the relative risk of disability for those with scores of 7‐9 ranged from 1.5 to 2.1, with similar consistent results for ADL disability. The observed rates of incident disability according to performance level in the Hispanic EPESE agreed closely with rates predicted from models developed from the EPESE sites. Receiver operating characteristic curves showed that gait speed alone performed almost as well as the full battery in predicting incident disability. Conclusions. Performance tests of lower extremity function accurately predict disability across diverse populations. Equations derived from models using both the summary score and the gait speed alone allow for the estimation of risk of disability in community-dwelling populations and provide valuable information for estimating sample size for clinical trials of disability prevention.

Review of Particle Physics

Abstract: This biennial Review summarizes much of particle physics. Using data from previous editions., plus 2778 new measurements from 645 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors., probability, and statistics. Among the 108 reviews are many that are new or heavily revised including those on CKM quark-mixing matrix, V-ud & V-us, V-cb & V-ub, top quark, muon anomalous magnetic moment, extra dimensions, particle detectors, cosmic background radiation, dark matter, cosmological parameters, and big bang cosmology.

A survey and overview of habitat fragmentation experiments.

Abstract: Habitat destruction and fragmentation are the root causes of many conservation problems. We conducted a literature survey and canvassed the ecological community to identify experimental studies of terrestrial habitat fragmentation and to determine whether consistent themes were emerging from these studies. Our survey revealed 20 fragmentation experiments worldwide. Most studies focused on effects of fragmentation on species richness or on the abundance(s) ofparticular species. Other important themes were the effect offragmentation in interspecific interactions, the role of corridors and landscape connectivity in in- dividual movements and species richness, and the influences of edge effects on ecosystem services. Our com- parisons showed a remarkable lack of consistency in results across studies, especially with regard to species richness and abundance relative to fragment size. Experiments with arthropods showed the best fit with the- oretical expectations of greater species richness on larger fragments. Highly mobile taxa such as birds and mammals, early-successional plant species, long-lived species, and generalist predators did not respond in the "expected" manner. Reasons for these discrepancies included edge effects, competitive release in the habitat fragments, and the spati.al scale of the experiments. One of the more consistently supported hypotheses was that movement and species richness are positively affected by corridors and connectivity, respectively. Tran- sient effects dominated many systems;,for example, crowding of individuals on fragments commonly was ob- served afterfragmentation, followed by a relaxation toward lower abundance in subsequentyears. The three long-term studies (?14 years) revealed strong patterns that would have been missed in short-term investiga- tions. Our results emphasize the wide range of species-specific responses to fragmentation, the need for eluci- dation of behavioral mechanisms affecting these responses, and the potentialfor changing responses to frag- mentation over time.

A review of collaborative partnerships as a strategy for improving community health

Abstract: ▪ Abstract Collaborative partnerships (people and organizations from multiple sectors working together in common purpose) are a prominent strategy for community health improvement. This review examines evidence about the effects of collaborative partnerships on (a) community and systems change (environmental changes), (b) community-wide behavior change, and (c) more distant population-level health outcomes. We also consider the conditions and factors that may determine whether collaborative partnerships are effective. The review concludes with specific recommendations designed to enhance research and practice and to set conditions for promoting community health.

Applying Positive Behavior Support and Functional Behavioral Assessment in Schools

Abstract: Positive behavior support (PBS) and functional behavioral assessment (FBA) are two significant concepts of the 1997 amendments to the Individuals with Disabilities Education Act. These two concepts...

Emotionally expressive coping predicts psychological and physical adjustment to breast cancer.

Abstract: This study tested the hypothesis that coping through emotional approach, which involves actively processing and expressing emotions, enhances adjustment and health status for breast cancer patients. Patients (n = 92) completed measures within 20 weeks following medical treatment and 3 months later. Women who, at study entry, coped through expressing emotions surrounding cancer had fewer medical appointments for cancer-related morbidities, enhanced physical health and vigor, and decreased distress during the next 3 months compared with those low in emotional expression, with age, other coping strategy scores, and initial levels on dependent variables (except medical visits) controlled statistically. Expressive coping also was related to improved quality of life for those who perceived their social contexts as highly receptive. Coping through emotional processing was related to one index of greater distress over time. Analyses including dispositional hope suggested that expressive coping may serve as a successful vehicle for goal pursuit.

Dehydration and melting experiments constrain the fate of subducted sediments

Abstract: [1] Geochemical tracers demonstrate that elements are cycled from subducted sediments into the arc melting regime at subduction zones, although the transfer mechanism is poorly understood. Are key elements (Th, Be, Rb) lost during sediment dehydration or is sediment melting required? To investigate this question, we conducted phase equilibria and trace element partitioning experiments on a pelagic red clay for conditions appropriate to the slab beneath arc volcanoes (2–4 GPa, 600°–1000°C). Using both piston cylinders and multianvils, we determined the solidus, phase stabilities, and major element compositions of coexisting phases. The solidus (H2O + Cl fluid-saturated) was located at 775 ± 25°C at 2 GPa, 810 ± 15°C at 3 GPa, and 1025 ± 25°C at 4 GPa with noevidence for complete miscibility between melt and fluid. This sediment composition produces a profusion of phases both above and below the solidus: garnet, jadeitic pyroxene, alkali-rich amphibole, phengite, biotite, magnetite, coesite, kyanite, apatite, zircon, Cl-rich fluids, and peraluminous to peralkaline granitic melts. At 2 GPa the phengite dehydration solidus is at 800°–825°C, while biotite breaks down between 850° and 900°C. To explore trace element partitioning across the solidus at 2 GPa, we used diamonds to trap fluids and melts. Both the bulk sediment residues and diamond traps were analyzed postexperiment by inductively coupled plasma–mass spectrometry (ICP-MS) and inductively coupled plasma–atomic emission spectrometry (ICP-AES) for 40 elements for which we calculated bulk partition coefficients (D = Csolid/Cfluid). Below the solidus, Rb, Sr, Ba, and Pb showed the greatest mobility (D ∼ 0.5–1.0), while at the solidus, Th and Be became notably partitioned into the melt (D values changing from >2.0 to <1.0). K and Rb D values fall below 1.0 when the micas breakdown. Only at the solidus do Th and Rb attain similar partition coefficients, a condition required by arc data. Taken together, the experimental results indicate that critical elements (Th and Be) require sediment melting to be efficiently transferred to the arc. This conclusion is at odds with most thermal models for subduction zones, which predict slab temperatures more than 100°C lower than sediment solidi. Thus the condition of sediment melting (with oceanic crust dehydration) may provide new constraints on the next generation of thermal/geodynamical models of subduction zones.

Acoustic characteristics of English fricatives.

Abstract: This study constitutes a large-scale comparative analysis of acoustic cues for classification of place of articulation in fricatives. To date, no single metric has been found to classify fricative place of articulation with a high degree of accuracy. This study presents spectral, amplitudinal, and temporal measurements that involve both static properties (spectral peak location, spectral moments, noise duration, normalized amplitude, and F2 onset frequency) and dynamic properties (relative amplitude and locus equations). While all cues (except locus equations) consistently serve to distinguish sibilant from nonsibilant fricatives, the present results indicate that spectral peak location, spectral moments, and both normalized and relative amplitude serve to distinguish all four places of fricative articulation. These findings suggest that these static and dynamic acoustic properties can provide robust and unique information about all four places of articulation, despite variation in speaker, vowel context, and voicing.

Host cyclooxygenase-2 modulates carcinoma growth

Abstract: Cyclooxygenase-2 (COX-2; Ptgs2) acts as a tumor promoter in rodent models for colorectal cancer, but its precise role in carcinogenesis remains unclear. We evaluated the contribution of host-derived COX-1 and COX-2 in tumor growth using both genetic and pharmacological approaches. Lewis lung carcinoma (LLC) cells grow rapidly as solid tumors when implanted in C57BL/6 mice. We found that tumor growth was markedly attenuated in COX-2(-/-), but not COX-1(-/-) or wild-type mice. Treatment of wild-type C57BL/6 mice bearing LLC tumors with a selective COX-2 inhibitor also reduced tumor growth. A decrease in vascular density was observed in tumors grown in COX-2(-/-) mice when compared with those in wild-type mice. Because COX-2 is expressed in stromal fibroblasts of human and rodent colorectal carcinomas, we evaluated COX-2(-/-) mouse fibroblasts and found a 94% reduction in their ability to produce the proangiogenic factor, VEGF. Additionally, treatment of wild-type mouse fibroblasts with a selective COX-2 inhibitor reduced VEGF production by 92%.

The practice of competency modeling

Abstract: The purpose of this article is to define and explain a trend that has caused a great deal of confusion among HR researchers, practitioners, and consumers of HR-related services: competency modeling The Job Analysis and Competency Modeling Task Force, a work group jointly sponsored by the Professional Practice Committee and the Scientific Affairs Committee of the Society For Industrial and Organizational Psychology, has recently concluded a 2-year investigation into the antecedents of competency modeling and an examination of the current range of practice Competency modeling is compared and contrasted to job analysis using a conceptual framework (reflected in a 10-dimension Level of Rigor Scale) that practitioners and researchers may use to guide future work efforts, and which could be used as a basis for developing standards for practice The strengths and weaknesses of both competency modeling and job analysis are identified and, where appropriate, recommendations are made for leveraging strengths in one camp to shore-up weaknesses in the other

Rib fractures in the elderly.

Abstract: BACKGROUND: We sought to ascertain the extent to which advanced age influences the morbidity and mortality after rib fractures (fxs), to define the relationship between number of rib fractures and morbidity and mortality, and to evaluate the influence of analgesic technique on outcome. METHODS: A retrospective cohort study involving all 277 patients > or = 65 years old with rib fxs admitted to a Level I trauma center over 10 years was undertaken. The control group consisted of 187 randomly selected patients, 18 to 64 years old, with rib fxs admitted over the same time period. Outcomes included pulmonary complications, number of ventilator days, length of intensive care unit and hospital stay (LOS), disposition, and mortality. The specific analgesic technique used was also examined. RESULTS: The two groups had similar mean number of rib fxs (3.6 elderly vs. 4.0 young), mean chest Abbreviated Injury Scores (3.0 vs. 3.0), and mean Injury Severity Score (20.7 vs. 21.4). However, mean number of ventilator days (4.3 vs. 3.1), intensive care unit days (6.1 vs. 4.0), and LOS (15.4 vs. 10.7 days) were longer for the elderly patients. Pneumonia occurred in 31% of elderly versus 17% of young (p 2 days) was associated with a 10% mortality versus 16% without the use of an epidural (p = 0.28). In the younger group (LOS >2 days), mortality with and without the use of an epidural was 0% and 5%, respectively. CONCLUSION: Elderly patients who sustain blunt chest trauma with rib fxs have twice the mortality and thoracic morbidity of younger patients with similar injuries. For each additional rib fracture in the elderly, mortality increases by 19% and the risk of pneumonia by 27%. As the number of rib fractures increases, there is a significant increase in morbidity and mortality in both groups, but with different patterns for each group. Further prospective study is needed to determine the utility of epidural analgesia in this population.

Cultural sensitivity in substance use prevention

Abstract: The rationale for targeted and tailored substance use prevention programs derives from essentially three observations: 1) differences in substance use prevalence rates across racial/ethnic groups; 2) differences in the prevalence of the risk factors for substance use across racial/ethnic groups; and 3) differences in the predictors of substance use across groups. This article provides a model for understanding cultural sensitivity as it pertains to substance use prevention. Cultural sensitivity is defined by two dimensions, surface and deep structure. Surface structure involves matching intervention materials and messages to observable, “superficial” characteristics of a target population. This may involve using people, places, language, product brands, music, food, locations, and clothing familiar to, and preferred by, the target audience. Surface structure refers to how well interventions fit within a specific culture. Deep structure involves incorporating the cultural, social, historical, environmental, and psychologic forces that influence the target health behavior in the proposed target population. For example, peer influences may exert a greater influence on substance use initiation among White and Hispanic than among African American youth, while parental influences may be stronger among African Americans. Whereas surface structure generally increases the "receptivity" or "acceptance" of messages, deep structure conveys salience. Techniques for developing culturally sensitive interventions, borrowed from social marketing and health communication theory, are described. © 2000 John Wiley & Sons, Inc.

Prevention and Treatment of Postoperative Nausea and Vomiting

Abstract: Pain, nausea and vomiting are frequently listed by patients as their most important perioperative concerns. With the change in emphasis from an inpatient to outpatient hospital and office-based medical/surgical environment, there has been increased interest in the ‘big little problem’ of postoperative nausea and vomiting (PONV). Currently, the overall incidence of PONV is estimated to be 25 to 30%, with severe, intractable PONV estimated to occur in approximately 0.18% of all patients undergoing surgery. PONV can lead to delayed postanaesthesia care unit (PACU) recovery room discharge and unanticipated hospital admission, thereby increasing medical costs. The aetiology and consequences of PONV are complex and multifactorial, with patient-, medical- and surgery-related factors. A thorough understanding of these factors, as well as the neuropharmacology of multiple emetic receptors [dopaminergic, muscarinic, cholinergic, opioid, histamine, serotonin (5-hydroxy-tryptamine; 5-HT)] and physiology [cranial nerves VIII (acoustic-vestibular), IX (glossopharyngeal) and X (vagus), gastrointestinal reflex] relating to PONV are necessary to most effectively manage PONV. Commonly used older, traditional antiemetics for PONV include the anticholinergics (scopolamine), phenothiazines (promethazine), antihistamines (diphenhydramine), butyrophenones (droperidol) and benzamides (metoclopramide). These antiemetics have adverse effects such as dry mouth, sedation, hypotension, extrapyramidal symptoms, dystonic effects and restlessness. The newest class of antiemetics used for the prevention and treatment of PONV are the serotonin receptor antagonists (ondansetron, granisetron, tropisetron, dolasetron). These antiemetics do not have the adverse effects of the older, traditional antiemetics. Headache and dizziness are the main adverse effects of the serotonin receptor antagonists in the dosages used for PONV. The serotonin receptor antagonists have improved antiemetic effectiveness but are not as completely efficacious for PONV as they are for chemotherapy-induced nausea and vomiting. Older, traditional antiemetics (such as droperidol) compare favourably with the serotonin receptor antagonists regarding efficacy for PONV prevention. Combination antiemetic therapy improves efficacy for PONV prevention and treatment. In the difficult-to-treat PONV patient (as in the chemotherapy patient), suppression of numerous emetogenic peripheral stimuli and central neuroemetic receptors may be necessary. This multimodal PONV management approach includes use of: (i) multiple different antiemetic medications (double or triple combination antiemetic therapy acting at different neuroreceptor sites); (ii) less emetogenic anaesthesia techniques; (iii) adequate intravenous hydration; and (iv) adequate pain control.

Development of a syngeneic mouse model for events related to ovarian cancer

Abstract: Mouse ovarian surface epithelial cells (MOSEC) were obtained from virgin, mature mice by mild trypsinization and were repeatedly passaged in vitro. Early passage cells (<20 passages) exhibited a cobblestone morphology and contact inhibition of growth. After approximately 20 passages in vitro, cobblestone morphology and contact inhibition of growth was lost. Tumor forming potential was determined by s.c. and i.p. injection of early and late passage cells into athymic and syngeneic C57BL6 mice. Subcutaneous tumors formed in approximately 4 months and were present only at the injection site. Intraperitoneal injection of late passage MOSEC into athymic and syngeneic mice resulted in growth of tumor implants throughout the abdominal cavity, and production of hemorrhagic ascitic fluid. Early passage MOSEC did not form tumors in vivo. Histopathologic analysis of tumors revealed a highly malignant neoplasm containing both carcinomatous and sarcomatous components. Late passage MOSEC expressed cytokeratin and did not produce ovarian steroids in response to gonadotropin stimulation in vitro. Ten clonal lines were established from late passage MOSEC. Each clone formed multiple peritoneal tumors and ascitic fluid after i.p. injection into C57BL6 mice. Three cell lines examined cytogenetically were polyploid with near-tetraploid modal chromosome numbers. Common clonal chromosome gains and losses included +5, +15, +19 and -X, -3, -4. One cell line had a clonal translocation between chromosomes 15 and 18 and another had a small marker chromosome; common structural abnormalities were not observed. These data describe the development of a mouse model for the study of events related to ovarian cancer in humans. The ability of the MOSEC to form extensive tumors within the peritoneal cavity, similar to those seen in women with Stage III and IV cancer, and the ability of the MOSEC to produce tumors in mice with intact immune systems, makes this model unique for investigations of molecular and immune interactions in ovarian cancer development.

Two-phase flow model of the cathode of PEM fuel cells using interdigitated flow fields

Abstract: When interdigitated gas distributors are used in a PEM fuel cell, fluids entering the fuel cell are forced to flow through the electrodes porous layers. This characteristic increases transport rates of the reactants and products to and from the catalyst layers and reduces the amount of liquid water entrapped in the porous electrodes thereby minimizing electrode flooding. To investigate the effects of the gas and liquid water hydrodynamics on the performance of an air cathode of a PEM fuel cell employing an interdigitated gas distributor, a 2-D, two-phase, multicomponent transport model was developed. Darcy's law was used to describe the transport of the gas phase. The transport of liquid water through the porous electrode is driven by the shear force of gas flow and capillary force. An equation accounting for both forces was derived for the liquid phase transport in the porous gas electrode. Higher differential pressures between inlet and outlet channels yield higher electrode performance, because the oxygen transport rates are higher and liquid water removal is more effective. The electrode thickness needs to be optimized to get optimal performance because thinner electrode may reduce gas-flow rate and thicker electrode may increase the diffusion layer thickness. For a fixed-size electrode, more channels and shorter shoulder widths are preferred.

Coping through emotional approach: scale construction and validation.

Abstract: Four studies demonstrate the psychometric adequacy and validity of scales designed to assess coping through emotional approach. In separate undergraduate samples, exploratory and confirmatory factor analyses of dispositional (Study 1) and situational (Study 3) coping item sets yielded 2 distinct emotional approach coping factors: emotional processing (i.e., active attempts to acknowledge and understand emotions) and emotional expression. The 2 scales yielded high internal consistency and test-retest reliability, as well as convergent and discriminant validity. A study (Study 2) of young adults and their parents established the scales' interjudge reliabilities. Longitudinal (Study 3) and experimental (Study 4) research supported the predictive validity of the emotional approach coping scales with regard to adjustment to stressful encounters. Findings highlight the utility of functionalist theories of emotion as applied to coping theory.

State Agent or Citizen Agent: Two Narratives of Discretion

Abstract: This article is based on the first two chapters of the authors' forthcoming book, Citizen-Agents: Stories from the Front-lines of Governing. The research

Outcome Measures in Acute Stroke Trials A Systematic Review and Some Recommendations to Improve Practice

Abstract: Background—There is little consistency in the measurement of outcome in acute stroke trials, and this may complicate interpretation of the results and reduce the likelihood of detecting worthwhile drug effects. This study aims to investigate empirically the measures used to date and to give recommendations for future studies. Summary of Comment—A systematic review of all published randomized studies of acute stroke drug intervention was undertaken, and the measures used were recorded. Fifty-one studies involving 57 214 subjects were identified. These studies used 14 different measures of impairment, 11 different measures of activity, 1 measure of “quality of life,” and 8 miscellaneous other measures. Timing of outcome assessments varied from 1 week to 1 year, with the modal time being 3 months. Many studies used ordinal measures but dichotomized results for analysis. Of the 51 studies included in the review, only 21 demonstrated benefit with the defined primary outcome measure. In several studies, however...

Head injury and the risk of AD in the MIRAGE study

Abstract: Objectives: It has been suggested in some studies that head injury is a risk factor for AD, and that this risk is heightened among carriers of the APOE -e4 allele. We examined the effects of head injury and APOE genotype on AD risk in a large family study. Subjects: A total of 2,233 probands who met criteria for probable or definite AD and their 14,668 first-degree family members (4,465 parents, 7,694 siblings, and 2,509 spouses) were ascertained at 13 centers in the United States, Canada, and Germany participating in the MIRAGE (Multi-Institutional Research in Alzheimer Genetic Epidemiology) project. Information on head injury was collected by interview of multiple informants and review of medical records. Nondemented relatives and spouses served as control subjects for this study. Methods: Odds of AD for head trauma with or without loss of consciousness were computed by comparing probands with unaffected spouses using conditional logistic regression analysis. To account for the unique biologic relationship between probands and their parents and siblings, odds of AD were computed using a generalized estimating equation (GEE) Poisson regression approach. GEE logistic regression was used to examine the joint effects of APOE genotype and head injury on the odds of AD in probands and a control group comprised of unaffected siblings and spouses. Results: Comparison of probands with their unaffected spouses yielded odds ratios for AD of 9.9 (95% CI, 6.5 to 15.1) for head injury with loss of consciousness and 3.1 (2.3 to 4.0) for head injury without loss of consciousness. The corresponding odds derived from the comparison of probands with their parents and sibs were 4.0 (2.9 to 5.5) for head injury with loss of consciousness and 2.0 (1.5 to 2.7) for head injury without loss of consciousness. Head injury without loss of consciousness did not significantly increase the risk of AD in spouses (OR = 1.3; 95% CI, 0.4 to 4.1). The joint effects of head injury and APOE genotype were evaluated in a subsample of 942 probands and 327 controls (spouses and siblings). Head injury increased the odds of AD to a greater extent among those lacking e4 (OR = 3.3) than among e4 heterozygotes (OR = 1.8) or homozygotes (OR = 1.3). Conclusion: Head injury is a risk factor for AD. The magnitude of the risk is proportional to severity and heightened among first-degree relatives of AD patients. The influence of head injury on the risk of AD appears to be greater among persons lacking APOE -e4 compared with those having one or two e4 alleles, suggesting that these risk factors may have a common biologic underpinning.

Prospective Long-Term Study of Vagus Nerve Stimulation for the Treatment of Refractory Seizures

Abstract: Summary: Purpose: To determine the long-term efficacy of vagus nerve stimulation (VNS) for refractory seizures. VNS is a new treatment for refractory epilepsy. Two short-term double-blind trials have demonstrated its safety and efficacy, and one long-term study in 114 patients has demonstrated a cumulative improvement in efficacy at 1 year. We report the largest prospective long-term study of VNS to date. Methods: Patients with six or more complex partial or generalized tonic-clonic seizures enrolled in the pivotal EOS study were prospectively evaluated for 12 months. The primary outcome variable was the percentage reduction in total seizure frequency at 3 and 12 months after completion of the acute EO5 trial, compared with the preimplantation baseline. Subjects originally randomized to low stimulation (active-control group) were crossed over to therapeutic stimulation settings for the first time. Subjects initially randomized to high settings were maintained on high settings throughout the 12-month study. Results: The median reduction at 12 months after completion of the initial double-blind study was 45%. At 12 months, 35% of 195 subjects had a >50% reduction in seizures, and 20% of 195 had a >75% reduction in seizures. Conclusions: The efficacy of VNS improves during 12 months, and many subjects sustain >75% reductions in seizures.

Headache and major depression: is the association specific to migraine?

Abstract: Objective: To examine the relationship between migraine and major depression, by estimating the risk for first-onset major depression associated with prior migraine and the risk for first migraine associated with prior major depression. We also examined the extent to which comorbidity with major depression is specific to migraine or is observed in other severe headaches. Methods: Representative samples of persons 25 to 55 years of age with migraine or other severe headaches (i.e., disabling headaches without migraine features) and controls with no history of severe headaches were identified by a telephone survey and later interviewed in person to ascertain history of common psychiatric disorders. Results: Lifetime prevalence of major depression was approximately three times higher in persons with migraine and in persons with severe headaches compared with controls. Significant bidirectional relationships were observed between major edepression and migraine, with migraine predicting first-onset depression and depression predicting first-onset migraine. In contrast, persons with severe headaches had a higher incidence of first-onset major depression (hazard ratio = 3.6), but major depression did not predict a significantly increased incidence of other severe headaches (hazard ratio = 1.6). Conclusions: The contrasting results regarding the relationship of major depression with migraine versus other severe headaches suggest that different causes may underlie the co-occurrence of major depression in persons with migraine compared with persons with other severe headaches.

Promoting Causal Agency: The Self-Determined Learning Model of Instruction

Abstract: Teachers seeking to promote the self-determination of their students must enable them to become self-regulated problem-solvers. This article introduces a model of teaching, The Self-Determined Learning Model of Instruction, incorporating principles of self-determination, which enables teachers to teach students to become causal agents in their own lives. This model was field-tested with students with disabilities. Students receiving instruction from teachers using the model attained educationally relevant goals, showed enhanced self-determination, and communicated their satisfaction with the process. Teachers implementing the model likewise indicated their satisfaction with the process and suggested that they would continue to use the model after the completion of the field test.

A Comparison of Several Approaches to Missing Attribute Values in Data Mining

Abstract: In the paper nine different approaches to missing attribute values are presented and compared. Ten input data files were used to investigate the performance of the nine methods to deal with missing attribute values. For testing both naive classification and new classification techniques of LERS (Learning from Examples based on Rough Sets) were used. The quality criterion was the average error rate achieved by ten-fold cross-validation. Using the Wilcoxon matched-pairs signed rank test, we conclude that the C4.5 approach and the method of ignoring examples with missing attribute values are the best methods among all nine approaches; the most common attribute-value method is the worst method among all nine approaches; while some methods do not differ from other methods significantly. The method of assigning to the missing attribute value all possible values of the attribute and the method of assigning to the missing attribute value all possible values of the attribute restricted to the same concept are excellent approaches based on our limited experimental results. However we do not have enough evidence to support the claim that these approaches are superior.

Prostacyclin-mediated activation of peroxisome proliferator-activated receptor δ in colorectal cancer

Abstract: There is evidence from both genetic and pharmacologic studies to suggest that the cyclooxygenase-2 (COX-2) enzyme plays a causal role in the development of colorectal cancer. However, little is known about the identity or role of the eicosanoid receptor pathways activated by COX-derived prostaglandins (PG). We previously have reported that COX-2-derived prostacyclin promotes embryo implantation in the mouse uterus via activation of the nuclear hormone receptor peroxisome proliferator-activated receptor (PPAR) delta. In light of the recent finding that PPARdelta is a target of beta-catenin transactivation, it is important to determine whether this signaling pathway is operative during the development of colorectal cancer. Analysis of PPARdelta mRNA in matched normal and tumor samples revealed that expression of PPARdelta, similar to COX-2, is up-regulated in colorectal carcinomas. In situ hybridization studies demonstrate that PPARdelta is expressed in normal colon and localized to the epithelial cells at the very tips of the mucosal glands. In contrast, expression of PPARdelta mRNA in colorectal tumors was more widespread with increased levels in transformed epithelial cells. Analysis of PPARdelta and COX-2 mRNA in serial sections suggested they were colocalized to the same region within a tumor. Finally, transient transfection assays established that endogenously synthesized prostacyclin (PGI(2)) could serve as a ligand for PPARdelta. In addition, the stable PGI(2) analog, carbaprostacyclin, and a synthetic PPARdelta agonist induced transactivation of endogenous PPARdelta in human colon carcinoma cells. We conclude from these observations that PPARdelta, similar to COX-2, is aberrantly expressed in colorectal tumors and that endogenous PPARdelta is transcriptionally responsive to PGI(2). However, the functional consequence of PPARdelta activation in colon carcinogenesis still needs to be determined.