Comparing the efficiency of estimates in concrete errors-in-variables models under unknown nuisance parameters

We consider a regression of y on x given by a pair of mean and variance functions with a parameter vector θ to be estimated that also appears in the distribution of the regressor variable x. The estimation of θ is based on an extended quasi score (QS) function. Of special interest is the case where the distribution of x depends only on a subvector α of θ, which may be considered a nuisance parameter. A major application of this model is the classical measurement error model, where the corrected score (CS) estimator is an alternative to the QS estimator. Under unknown nuisance parameters we derive conditions under which the QS estimator is strictly more аfficient than the CS estimator. We focus on the loglinear Poisson, the Gamma, and the logit model

Acceptance of oral chemotherapy in breast cancer patients - a survey study

<p>Abstract</p> <p>Background</p> <p>Oral (p.o.) chemotherapy treatments gained increasing importance in the palliative treatment of metastatic breast cancer (MBC). Aim of this survey was to evaluate the acceptance of p.o. treatment and patients' individual attitudes towards it.</p> <p>Methods</p> <p>A specific 14 item-questionnaire was designed. Patients suffering from breast cancer receiving a newly launched p.o. or i.v. chemotherapy treatment were prospectively evaluated during 4 months of time. 224 questionnaires using descriptive statistics, chi-square test, Spearman correlation were evaluated.</p> <p>Results</p> <p>Patients' median age was 54 years, 164 received i.v., 60 p.o therapy. 89% with p.o. and 67% with i.v. regimens would choose p.o. over i.v. therapy, if equal efficacy is guaranteed. Significant differences were especially found in terms of personal benefit (55% i.v., 92% p.o.), reduced feeling of being ill due to p.o. treatment (26% i.v., 65% p.o.), better coping with disease due to p.o. therapy (36% i.v., 68% p.o.). Side effects were significantly less often reported under p.o. treatment (19% p.o. vs. 53% i.v.)</p> <p>Conclusion</p> <p>P.o. chemotherapy shows a high acceptance in MBC patients under palliative therapy. Compliance can be achieved in particular through a differentiated indication, patient education and competent support along a p.o. treatment.</p

Relationship of Hypochaeris salzmanniana (Asteraceae, Lactuceae), an endangered species of the Iberian Peninsula, to H. radicata and H. glabra and biogeographical implications

Hypochaeris salzmanniana DC. (Asteraceae, Lactuceae) is an endangered species on the Iberian Peninsula, known from only eight coastal populations. Most authors have treated it as a variety, subspecies or simply as a synonym of H. glabra L. On the basis of morphological and cytological characters, Talavera recently separated H. salzmanniana (2n = 8) from H. glabra (2n = 10). Material of H. salzmanniana, H. glabra and H. radicata was collected from Spain, Italy, Sicily and Tunisia in order to assess taxonomic status and population relationships. Amplified Fragment Length Polymorphism (AFLP) analysis revealed three well-differentiated species. A close relationship between H. salzmanniana and H. radicata is also confirmed by AFLP analysis and chromosome number (2n = 8), morphology, and rDNA localization (FISH, fluorescence in situ hybridization). Hypochaeris salzmanniana and H. radicata share three fixed diagnostic AFLP fragments out of 348 fragments scored. The population structure of H. salzmanniana reveals distinct groups in southern Spain that are separated geographically. High differentiation among a western (Conil to Zahara), an intermediate (Punta Paloma and Los Algarbes) and an eastern (Algeciras and La Línea) group may reflect ancient separation. Population sizes and genetic compatibility differ greatly among populations and can be used to explain levels of within-population genetic diversity, together with recent documented loss of habitats resulting from tourist developments. Population structures of H. radicata and H. glabra show a similar geographical patterning: strongly differentiated populations from the Betic Cordillera and from the Iberian Massif, which are separated at present by the Guadalquivir river. Geological events at the end of the Tertiary (Tortonian-Messinian Miocene) might help explain patterns of differentiation in these three species of sect. Hypochaeris.Austrian Science Foundation FWF P-15225Ministerio de Ciencia y Tecnología PB96-1352, REN2002-04634-C05-03, REN2002-04354-C02-0

Relationship between Resilience, Psychological Distress and Physical Activity in Cancer Patients: A Cross-Sectional Observation Study.

Psychological distress remains a major challenge in cancer care. The complexity of psychological symptoms in cancer patients requires multifaceted symptom management tailored to individual patient characteristics and active patient involvement. We assessed the relationship between resilience, psychological distress and physical activity in cancer patients to elucidate potential moderators of the identified relationships. A cross-sectional observational study to assess the prevalence of symptoms and supportive care needs of oncology patients undergoing chemotherapy, radiotherapy or chemo-radiation therapy in a tertiary oncology service. Resilience was assessed using the 10-item Connor-Davidson Resilience Scale (CD-RISC 10), social support was evaluated using the 12-item Multidimensional Scale of Perceived Social Support (MSPSS) and both psychological distress and activity level were measured using corresponding subscales of the Rotterdam Symptom Checklist (RSCL). Socio-demographic and medical data were extracted from patient medical records. Correlation analyses were performed and structural equation modeling was employed to assess the associations between resilience, psychological distress and activity level as well as selected socio-demographic variables. Data from 343 patients were included in the analysis. Our revised model demonstrated an acceptable fit to the data (χ2(163) = 313.76, p = .000, comparative fit index (CFI) = .942, Tucker-Lewis index (TLI) = .923, root mean square error of approximation (RMSEA) = .053, 90% CI [.044.062]). Resilience was negatively associated with psychological distress (β = -.59), and positively associated with activity level (β = .20). The relationship between resilience and psychological distress was moderated by age (β = -0.33) but not social support (β = .10, p = .12). Cancer patients with higher resilience, particularly older patients, experience lower psychological distress. Patients with higher resilience are physically more active. Evaluating levels of resilience in cancer patients then tailoring targeted interventions to facilitate resilience may help improve the effectiveness of psychological symptom management interventions

Resolving the Ellsberg Paradox by Assuming that People Evaluate Repetitive Sampling

Ellsberg (1961) designed a decision experiment where most people violated the axioms of rational choice. He asked people to bet on the outcome of certain random events with known and with unknown probabilities. They usually preferred to bet on events with known probabilities. It is shown that this behavior is reasonable and in accordance with the axioms of rational decision making if it is assumed that people consider bets on events that are repeatedly sampled instead of just sampled once