1,204 research outputs found
Attribute Elicitation: Implications in the Research Context1
Three different methods of attribute elicitation for two different paper-based products were compared in this study. The three methods used were free elicitation (FE), hierarchical dichotomization (HD), and Kelly's repertory grid (RG). The two paper-based products used in this study were bathroom tissue and paper towels. The methods were compared by abstraction, efficiency in data collection, convergent validity, and respondents' reaction to the task. The results from this comparison indicated that the level of abstraction did not significantly differ between methods or products. However, a rank order analysis revealed that a substantial difference existed with 18 to 20% of the attributes being rated significantly different between the elicitation methods for paper towels and bathroom tissue, respectively. Convergent validity was exhibited between all the methods, although was found to be highest between HD and RG. These findings suggest that all three elicitation methods elicit very similar information from the consumers' knowledge base. The efficiency in data collection revealed that for both products FE took significantly less time to complete the task, as well as to elicit the individual attributes. Furthermore, HD was identified as being the least efficient of the methods for either product. For the comparison of the reaction to task, FE was found to be the least difficult of the three methods and also allowed the respondents to more freely express their opinion
Stressful life event appraisal and coping in patients with psychogenic seizures and those with epilepsy
AbstractUnderstanding stress and coping among individuals with psychogenic nonepileptic seizures (PNES) may have important treatment implications. 40 patients with PNES, 20 with epilepsy (EPIL), and 40 healthy control (HC) participants reported the frequency of various stressful life events (both positive and negative) and appraised the distress these events induced. They also described their habitual coping behaviors. PNES patients reported no more frequent stressful life events than EPIL patients or HC. In addition, the stressors they experienced are not objectively more severe. However, they reported more severe distress due to negative life events, especially in the domains of work, social functioning, legal matters, and health. PNES patients also engaged in less planning and active coping than HC. Neither of these two coping behaviors was associated with distress ratings. The PNES group did not engage in more denial than either group. However, greater denial among PNES patients was associated with greater perceived distress. Coping in PNES is characterized by elevated levels of perceived distress and fewer action strategies than are normally employed to reduce the impact of a stressor. These findings may inform cognitive behavioral therapy of PNES patients
Reprocessing Models for the Optical Light Curves of Hypervariable Quasars from the Sloan Digital Sky Survey Reverberation Mapping Project
We explore reprocessing models for a sample of 17 hypervariable quasars,
taken from the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM)
project, which all show coordinated optical luminosity hypervariability with
amplitudes of factors between 2014 and 2020. We develop and apply
reprocessing models for quasar light curves in simple geometries that are
likely to be representative of quasar inner environments. In addition to the
commonly investigated thin-disk model, we include the thick-disk and hemisphere
geometries. The thick-disk geometry could, for instance, represent a
magnetically-elevated disk, whereas the hemisphere model can be interpreted as
a first-order approximation for any optically-thick out-of-plane material
caused by outflows/winds, warped/tilted disks, etc. Of the 17 quasars in our
sample, eleven are best-fit by a hemisphere geometry, five are classified as
thick disks, and both models fail for just one object. We highlight the
successes and shortcomings of our thermal reprocessing models in case studies
of four quasars that are representative of the sample. While reprocessing is
unlikely to explain all of the variability we observe in quasars, we present
our classification scheme as a starting point for revealing the likely
geometries of reprocessing for quasars in our sample and hypervariable quasars
in general.Comment: 23 pages, 8 figures, submitted to Ap
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Longitudinal Study of Quality of Life in People with Advanced Alzheimer's Disease
The authors examined three indicators of health-related quality of life in people with advanced Alzheimer's disease ([AD]; N = 150): confinement to home, null activity, and null positive affect, as reported by patient proxies. Dementia severity predicted time-to-onset for all three disease milestones in models that controlled for sociodemographic indicators, nursing home status, and death in the follow-up period. Patients whose dementia worsened over follow-up were more likely to reach each milestone. These outcomes represent key milestones in the care of patients; they are sensitive to disease progression, and they are likely to be useful for studying treatment in advanced AD
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Psychopathological Features in Alzheimer's Disease: Course and Relationship with Cognitive Status
OBJECTIVES: To examine the course, clinical correlates, and relationship between cognitive status and psychopathological features in patients with probable Alzheimer's disease (AD) followed over a 5-year period. DESIGN: Cohort study with follow-up of 5 years. SETTING: Patients were recruited at three sites: 91 patients at Columbia Medical Center, 84 at Johns Hopkins School of Medicine, and 61 at Massachusetts General Hospital. PARTICIPANTS: Patients diagnosed with probable AD (n = 236) enrolled in a longitudinal study (Predictors study). MEASUREMENTS: Wandering/agitation, physical aggression, hallucinations, and delusions were evaluated at 6-month intervals using the Columbia Scale for Psychopathology in Alzheimer's Disease. Descriptive analyses were used to provide estimates of prevalence and course of psychopathological features. General estimating equations determined the odds of having any of the four psychopathological behaviors as a function of cognitive status. Markov analyses provided 6-month transition probabilities for psychopathological behaviors given patients' cognitive status and the presence or absence of such behaviors in the previous evaluation. RESULTS: For wandering/agitation, prevalence (39-57%) and persistence increased as a function of time and decrement in cognitive status. Physical aggression was less prevalent (6-22%) and increased as a function of cognitive decline but tended to persist only in the more severely impaired patients. Delusions (34-49%) reached a peak at the second year and then declined. The odds of delusions were maximal with intermediate decline but remained persistent regardless of cognitive status. Hallucinations, despite some fluctuations, were relatively stable during the follow-up period (8-17%) and moderately persistent. CONCLUSION: Psychopathological features, particularly wandering/agitation and delusions, in AD were common throughout the disease course. The natural history and persistence of the four psychopathological features varied. These findings provide important information to clinicians and caregivers regarding the course, predictability, and possible treatment of psychopathological behaviors in patients with probable AD
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Predicting Time to Nursing Home Care and Death in Individuals with Alzheimer Disease
Objective. —To develop and validate an approach that uses clinical features that can be determined in a standard patient visit to estimate the length of time before an individual patient with Alzheimer disease (AD) requires care equivalent to nursing home placement or dies. Design. —Prospective cohort study of 236 patients, followed up semiannually for up to 7 years. A second validation cohort of 105 patients was also followed. Setting. —Three AD research centers. Patients. —All patients met National Institute of Neurological and Communicative Disorders and Stroke—Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA) criteria for probable AD and had mild dementia at the initial visit. Intervention. —Predictive features, ascertained at the initial visit, were sex, duration of illness, age at onset, modified Mini-Mental State Examination (mMMS) score, and the presence or absence of extrapyramidal signs or psychotic features.Main Outcome Measures. —(1) Requiring the equivalent of nursing home placement and (2) death. Results. —Prediction algorithms were constructed for the 2 outcomes based on Cox proportional hazard models. For each algorithm, a predictor index is calculated based on the status of each predictive feature at the initial visit. A table that specifies the number of months in which 25%, 50%, and 75% of patients with any specific predictor index value are likely to reach the end point is then consulted.Survival curves for time to need for care equivalent to nursing home placement and for time to death derived from the algorithms for selected predictor indexes fell within the 95% confidence bands of actual survival curves for patients.When the predictor variables from the initial visit for the validation cohort patients were entered into the algorithm, the predicted survival curves for time to death fell within the 95% confidence bands of actual survival curves for the patients. Conclusions. —The prediction algorithms are a first but promising step toward providing specific prognoses to patients, families, and practitioners. This approach also has clear implications for the design and interpretation of clinical trials in patients with AD
Fractionation of lignocellulosic biomass with the ionic liquid 1-butylimidazolium hydrogen sulfate
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Predicting Time to Nursing Home Care and Death in Individuals with Alzheimer Disease
Objective. —To develop and validate an approach that uses clinical features that can be determined in a standard patient visit to estimate the length of time before an individual patient with Alzheimer disease (AD) requires care equivalent to nursing home placement or dies. Design. —Prospective cohort study of 236 patients, followed up semiannually for up to 7 years. A second validation cohort of 105 patients was also followed. Setting. —Three AD research centers. Patients. —All patients met National Institute of Neurological and Communicative Disorders and Stroke—Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA) criteria for probable AD and had mild dementia at the initial visit. Intervention. —Predictive features, ascertained at the initial visit, were sex, duration of illness, age at onset, modified Mini-Mental State Examination (mMMS) score, and the presence or absence of extrapyramidal signs or psychotic features.Main Outcome Measures. —(1) Requiring the equivalent of nursing home placement and (2) death. Results. —Prediction algorithms were constructed for the 2 outcomes based on Cox proportional hazard models. For each algorithm, a predictor index is calculated based on the status of each predictive feature at the initial visit. A table that specifies the number of months in which 25%, 50%, and 75% of patients with any specific predictor index value are likely to reach the end point is then consulted.Survival curves for time to need for care equivalent to nursing home placement and for time to death derived from the algorithms for selected predictor indexes fell within the 95% confidence bands of actual survival curves for patients.When the predictor variables from the initial visit for the validation cohort patients were entered into the algorithm, the predicted survival curves for time to death fell within the 95% confidence bands of actual survival curves for the patients. Conclusions. —The prediction algorithms are a first but promising step toward providing specific prognoses to patients, families, and practitioners. This approach also has clear implications for the design and interpretation of clinical trials in patients with AD
Exercise, APOE, and Working Memory: MEG and Behavioral Evidence for Benefit of Exercise in Epsilon4 Carriers
Performance on the Sternberg working memory task, and MEG cortical response on a variation of the Sternberg task were examined in middle-aged carriers and non-carriers of the APOE ε4 allele. Physical activity was also assessed to examine whether exercise level modifies the relationship between APOE genotype and neurocognitive function. Regression revealed that high physical activity was associated with faster RT in the six- and eight-letter conditions of the Sternberg in ε4 carriers, but not in the non-carriers after controlling for age, gender, and education (N = 54). Furthermore, the MEG analysis revealed that sedentary ε4 carriers exhibited lower right temporal lobe activation on matching probe trials relative to high-active ε4 carriers, while physical activity did not distinguish non-carriers (N = 23). The M170 peak was identified as a potential marker for pre-clinical decline as ε4 carriers exhibited longer M170 latency, and highly physically active participants exhibited greater M170 amplitude to matching probe trials
Soaking of Pine Wood Chips with Ionic Liquids for Reduced Energy Input during Grinding
Abstract Ionic liquids are of great interest as potential solvents/catalysts for the production of fuels and chemicals from lignocellulosic biomass. Attention has focussed particularly on the pretreatment of lignocellulose to make the cellulose more accessible to enzymatic hydrolysis. Any biomass processing requires a reduction in the size of the harvested biomass by chipping and/or grinding to make it more amenable to chemical and biological treatments. This paper demonstrates that significant energy savings can be achieved in the grinding of pine wood chips when the ionic liquid is added before the grinding operation. We show that this is due to the lubricating properties of the ionic liquids and not to physico-chemical modifications of the biomass. A brief impregnation of the chipped biomass results in higher savings than a longer treatment
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