Is HBT really puzzling?

Two-particle correlations from RHIC have provided a surprising snapshot of the final state at RHIC. In this talk I discuss the nature of the HBT puzzle and attempt to delineate several factors which might ultimately resolve the issue.Comment: Proceedings for WPCF, Kromeriz, Czech Republic, August 200

The Study of Optoelectronics in Semiconductor and Metallic Nanoparticle Hybrid Systems

This thesis examines optoelectronics of photonic crystals and photonic nanofibers, especially with quantum dots and metallic nanoparticles doped into them. The simulations produced focus on the quantum dots, which are presented in an ensemble of 3-level systems. In order to consider a photonic nanofiber in isolation, a model was developed for the density of photonic states. We studied two profiles, a square cross-section and a circular cross-section. In addition, we consider two architectures, one where a photonic crystal surrounds a dielectric fiber, and one where the fiber is another photonic crystal. We found several photonic nanofibers with a single bound photonic state and calculated the density of states. We studied dipole-dipole interactions through photon absorption in three-level quantum dots doped in a photonic nanofiber. The density matrix method was used to calculate the absorption coefficient and the mean field approximation was used to incorporate dipole-dipole interactions. It was found that a transparent state can become an absorbing state if the dipole-dipole interactions are switched on. It is also predicted that one absorbing peak can be split into two absorbing peaks through judicious selection of the resonance energies of the quantum dots and the location of the bound photon state in the nanofiber. We calculated the energy transfer and photoluminescence in donor and acceptor quantum dots which were embedded in a nonlinear photonic crystal. These quantum dots interacted via the dipole-dipole interaction. It was found that the photoluminescence of the acceptor quantum dot could be controlled by a pump laser. We have also studied the interactions between a metallic nanosphere and a quantum dot embedded on a dielectric substrate. Dipole-dipole interactions between them caused energy absorption, evaluated with the density matrix method. The absorption spectrum was found to switch from one peak to two peaks when the intensity of the control laser increased. Adding a metallic nanosphere can also cause splitting. Additionally, fluorescence efficiency in the quantum dot was found to be quenched by the presence of the metallic nanosphere. Finally, we studied quantum coherence and interference phenomena in a quantum dot and metallic nanorod hybrid system. It was predicted that the power absorption spectrum of the metallic nanorod can be switched from two transparent states to one transparent state by the control laser. These findings can be used to create ultrafast all-optical switching and sensing nanodevices. Also, the systems discussed here have applications in photovoltaics, quantum computation, and cryptography, among others

Improving quality of life in cancer patients through higher participation and health literacy: study protocol for evaluating the oncological social care project (OSCAR)

BACKGROUND: Cancer patients experience psychological and social distress due to their medical treatment and social issues. However, continuous and specialized social support is still lacking. In Germany, a group of company health insurance funds has developed an approach to support cancer patients with monthly structured interviews conducted by specially trained Social Care Nurses. The nurses will identify patient needs in order to provide help with medical, personal, and social matters. One aim of the scientific evaluation is to analyze the effect of the consultations on various patient-reported outcomes, especially quality of life. The evaluation concept will be described in this study protocol. METHODS/DESIGN: The evaluation is a non-randomized, controlled, multi-center intervention study with a mixed-method design. It consists of three research modules which include primary data from questionnaires, and claims data from the health insurance funds. In Module 1, cancer patients will be recruited to form an intervention group (OSCAR, n = 150) and a control group (n = 200) in four study centers for a period of 1 year. One baseline and three follow-up questionnaires will be conducted to survey the patient-reported outcomes. Relevant secondary outcomes are health literacy, participation, and physician-patient communication. In Module 2, claims data will be used to analyze cost effects and thereby assess effectivity and hospitalization. Module 3 will involve a qualitative analysis of project diaries kept by the Social Care Nurses. The diaries will record the nurses' practical experiences and the benefits of deploying OSCAR across the German healthcare system. DISCUSSION: OSCAR is an innovative way of providing cancer patients with continuous support to improve their quality of life. The evaluation concept aims to assess the effects of the monthly consultations by the Social Care Nurses on the patients, and will use a mixed-method design. The results are important for assessing the transferability of OSCAR to the healthcare system as a whole. TRIAL REGISTRATION: German Clinical Trials Register (DRKS-ID: DRKS00013640 ). Registered 29 December 2017

Amused, accepted, and used? Attitudes and emotions towards automated vehicles, their relationships, and predictive value for usage intention

Automated vehicles (AVs) have left the laboratories and can be experienced in several projects, e.g. at the premises of a clinic in Germany. With this transition, research on AV attitudes no longer needs to rely on questionnaires with hypothetical scenarios and simulations. Previous research – limited by the unavailability of AVs – has provided ambivalent results regarding age and gender differences in attitudes towards AVs. We present research results about the role of age and gender in connection with attitudes such as acceptance, perceived safety, and trust, as well as intention to use. We additionally demonstrate relationships between those constructs and emotions such as amusement, fear, and surprise. Data were collected from participants (n = 125) after having experienced an AV ride with level 4 automation on two campuses of a clinic in Berlin, Germany. Results reveal strong correlations between all attitudes (0.55 ≤ r ≤ 0.71; p < 0.01) and show acceptance and perceived safety to be solid predictors of intention to use AVs. We also found age to be a significant predictor for usage intention even when other attitudes are considered (β = −0.22; p < 0.01). MANOVA results point to gender differences in all constructs, but with limited confidence (5.40 ≤ F ≤ 18.34; p ≤ 0.02). However, we reject our hypothesis that young men are highly accepting, trusting, and intending to use AVs compared to other combinations of age and gender. We recommend using a mix of attitude, emotion, and behavioural (intention) measures in future research on AVs together with more transparency regarding construct definitions and study materials

Health-related quality of life after stroke rehabilitation: longitudinal observations and the impact of proxy interviews

Neben klinisch‐funktionalen Parametern gewinnen patientenberichtete Outcomes, wie die gesundheitsbezogene Lebensqualität, für die Beurteilung und Gestaltung von Therapien weiter an Relevanz. In der rehabilitativen Schlaganfallbehandlung und -forschung begründet sich diese Fokussierung einmal mehr vor dem Hintergrund von zum Teil irreversiblen motorischen und kognitiven Einschränkungen. Während in Akutklinik und Rehabilitationseinrichtung eine fortlaufende Beobachtung des Progresses realisierbar und vielfach beschrieben ist, findet sich über den weiteren Verlauf nach Entlassung sowie dort wirkende Einflussfaktoren wenig oder Widersprüchliches in der Literatur. Darüber hinaus werden nicht‐auskunftsfähige Patient*innen von der Erhebung patientenzentrierter Outcomes vielfach ausgeschlossen. Analyseleitend waren die Fragen, wie sich die Lebensqualität älterer Patient*innen mit Schlaganfall nach der Entlassung aus der neurologischen Rehabilitation entwickelt und welche Einflussfaktoren für die Prognose besondere Bedeutung zeigen. Die Perspektive nicht‐auskunftsfähiger Patient*innen wurde in Form von Proxy‐Interviews systematisch einbezogen. Vorliegende Mantelschrift fokussiert auf die Charakterisierung nicht-auskunftsfähiger Patient*innen und den Impact von Stellvertreterinterviews. Die Erhebung wurde in Form einer prospektiven Kohortenstudie realisiert. Auf eine initiale Face-to‐face‐Befragung in einer Brandenburger Rehabilitationsklinik folgten telefonische Follow‐ups nach 3, 6 und 12 Monaten. Mit dem EUROHIS‐QOL‐8 wurde ein validiertes Instrument zur Erfassung der Lebensqualität eingesetzt. Die Datenanalyse erfolgte deskriptiv sowie unter Anwendung Linearer Gemischter Modelle. Im Durchschnitt berichteten die 411 eingeschlossenen Patient*innen (mittleres Alter 75 Jahre (SD 5,8 Jahre), Frauenanteil 47,9 %), davon 89 Stellvertreter*innen, eine Verringerung der Lebensqualität im ersten Jahr nach Entlassung. Selbst teilnehmende Patient*innen wiesen eine höhere Lebensqualität, begünstigende soziale Faktoren und bessere klinische Scores als nicht‐auskunftsfähige Patienten*innen auf. Als zentrale Prädiktoren für eine geringere Lebensqualität zeigten sich ein erhöhter Schmerzstatus, ein positives Depressionsscreening, eine starke funktionale und kognitive Betroffenheit sowie soziale Netzwerke von geringerer Größe (< 10 Personen). Die zum Ende der Rehabilitation berichtete Lebensqualität konnte in den folgenden 12 Monaten mehrheitlich weder verfestigt noch ausgebaut werden. Im Interesse der Patient*innen, aber auch aus gesundheitsökonomischer Perspektive erscheint die Etablierung eines Monitorings oder Re‐Assessments relevanter Parameter angezeigt, um bestehende Therapien zeitnah anpassen zu können. Die Berücksichtigung von Stellvertreter*innen im Falle nicht‐auskunftsfähiger Patienten ist methodisch und ethisch essentiell, um das Risiko einer systematischen Überschätzung der Lebensqualität und klinischer Scores zu verringern und ihre Präferenzen zu erfassen.In addition to clinical-functional parameters, patient-reported outcomes, such as health-related quality of life, are becoming increasingly relevant for the assessment and design of therapies. In rehabilitative stroke treatment and research, this focus is justified against the background of frequently irreversible motoric and cognitive limitations. Continuous monitoring of progress is feasible in acute care and rehabilitation facilities and has been described before. Little and contradictory information is found in the literature about the further course after discharge and the factors influencing it. Patients who are not able to provide information themselves are often excluded from the survey of patient-centred outcomes. The analysis was guided by the questions of how quality of life of elderly stroke patients develops after discharge from neurological rehabilitation and which factors are of particular importance for progress. Patients who were unable to provide information were systematically included by proxy interviews. The present thesis focuses on the characterisation of patients who are not able to provide information and the impact of proxy interviews. The survey was realized as a prospective cohort study. An initial face-to-face survey in a rehabilitation clinic located in Brandenburg was followed by telephone follow-up interviews after 3, 6 and 12 months. For assessment of quality of life the validated instrument EUROHIS-QOL-8 was used. Data analysis was carried out descriptively and by using linear mixed models. On average, the four-hundred-eleven patients (mean age 75 years (SD 5.8 years), proportion of women 47.9 %), 89 of them were proxies, reported a reduction in quality of life within the first year after discharge from neurological rehabilitation. Self-reporting patients stated higher quality of life, favourable social characteristics and clinical scores than patients who were unable to provide information. Central predictors of a lower quality of life were an increased pain status, positive depression screening, a high degree of functional and cognitive impairment and smaller social networks (< 10 persons). Quality of life scores reported at rehabilitation discharge are often not lasting. From a patients, but also a health economic perspective the establishment of a monitoring or re-assessment of relevant parameters appears to be advisable in order to be able to adapt or supplement existing therapies adequately and timely. Performing proxy interviews in the case of patients who are unable to provide information is methodologically and ethically essential in order to reduce the risk of systematic overestimation of quality of life and clinical scores and to record patient preferences

Quality of life after stroke rehabilitation discharge: a 12-month longitudinal study

PURPOSE To analyse trends in quality of life (QoL) development among older stroke patients within the first year after rehabilitation discharge, and to investigate the impact of including proxy interviews in research and practice. METHODS A prospective cohort study with follow-up at 3, 6, and 12 months with 411 patients and proxy respondents was conducted. The EUROHIS-QOL 8-item index was used to assess QoL. By performing descriptive analyses, QoL development over time was compared among subgroups. Linear mixed models were calculated to estimate mean changes from baseline to 12-month follow-up. The effects of patient characteristics and time on QoL were investigated using comprehensive mixed models. RESULTS One year after rehabilitation discharge, the majority of patients had neither maintained nor regained their initial QoL. Proxy respondents reported significantly lower QoL (22.6-29.5 points, p < 0.001). Characteristics associated with lower QoL were stroke severity, depression, and pain. Having a small social network was negatively associated with QoL (-1.66 points, 95%CI: -2.84/-0.48, p = 0.006). CONCLUSIONS Quality of life scores reported at the time of rehabilitation discharge are often not lasting. Including severely impaired patients via proxies reduces the risk of overestimating QoL outcomes. Outpatient's characteristics should be taken into account when planning therapy strategies to maintain previously achieved health goals. Regular re-assessments are required.Implications for rehabilitationThere should be an awareness that improvements in quality of life (QoL) achieved during rehabilitation are not sustainable.Regularly re-assessing pain status, psychological burden, and social network size could help clinicians to determine treatment strategies for maintaining and improving rehabilitation achievements.Conducting proxy interviews is required to assess disease burden of patients with severe stroke (e.g., non-linguistic patients)

Characteristics and patient-reported outcomes associated with dropout in severely affected oncological patients: an exploratory study

Background: Patient-reported outcome measures (PROMs) are commonly-used surrogates for clinical outcomes in cancer research. When researching severe diseases such as cancer, it is difficult to avoid the problem of incomplete questionnaires from drop-outs or missing data from patients who pass away during the observation period. The aim of this exploratory study was to explore patient characteristics and the patient-reported outcomes associated with the time-to-dropout. Methods: In an Oncological Social Care Project (OSCAR) study, the condition of the participants was assessed four times within 12 months (t0: baseline, t1: 3 months, t2: 6 months, and t3: 12 months) by validated PROMs. We performed competing-risk regressions based on Fine and Gray's proportional sub-distribution hazards model for exploring factors associated with time-to-dropout. Death was considered a competing risk. Results: Three hundred sixty-two participants were analyzed in the study. 193 (53.3%) completed a follow-up after 12 months, 67 (18.5%) patients dropped out, and 102 patients (28.2%) died during the study period. Poor subjective social support was related to a higher risk of drop-out (SHR = 2.10; 95%CI: 1.01-4.35). Lower values in health-related quality of life were related to drop-out and death. The sub-scales global health status/QoL, role functioning, physical functioning, and fatigue symptom in the EORTC QLQ-C30 were key characteristics of early drop-out. Conclusion: Severely affected cancer patients with poor social support and poor quality of life seem more likely to drop out of studies than patients with higher levels of social support and a better quality of life. This should be considered when planning studies to assess advanced cancer patients. Methods of close continued monitoring should be actively used when patient experiences a substantial deterioration in their health-related quality of life and symptoms during the study. Results for such studies have to be interpreted with caution in light of specific drop-out mechanisms

A retrospective analysis of the health and social situation of homeless people in Berlin: study protocol

Background: Homelessness is often described as both a driver and a consequence of poor health, social exclusion and economic marginalisation. The present protocol provides a detailed description of the study Examining the health situation of homeless people in Berlin: a retrospective analysis of data from the health centre for the homeless of the Jenny De la Torre Foundation from 2006 to 2020 (GIG study). The primary objective of the GIG study is to describe and analyse the social and health situation of homeless people in Berlin. Methods: A retrospective secondary data analysis of an anonymous full census of medical records for the years 2006 until 2020 from a health centre for homeless people will be carried out. The main outcome is the description and analysis of the social and health situation of homeless people in Berlin. Total and cross-sectional sample characteristics will be presented in a descriptive analysis using Chi-Square Test, Mann-Whitney-U-Test or independent t-Test as appropriate to test (sub) group differences. Further, outcomes will be analysed using finite mixture modelling in order to distinguish different types of social and health conditions. Latent variable regressions will be applied in order to identify sociodemographic and disease-related factors associated with decreasing health conditions. Discussion: Given the high number of homeless individuals in Germany, it is of great importance to examine their social and health situation in order to gain a better understanding of challenges and needs of homeless people and work on new approaches and solutions to effectively address these. Trail registration: The study was prospectively registered with the German Clinical Trials Register (trial registration number: DRKS00021172). Registered 26 June 2020

Identifying and handling unbalanced baseline characteristics in a non-randomized, controlled, multicenter social care nurse intervention study for patients in advanced stages of cancer

Purpose: Given the psychosocial burdens patients in advanced stages of cancer face, innovative care concepts are needed. At the same time, such vulnerable patient groups are difficult to reach for participation in intervention studies and randomized patient inclusion may not be feasible. This article aims to identify systematic biases respectively selection effects occurring during the recruitment phase and to discuss their potential causes based on a non-randomized, multicenter intervention study with patients in advanced stages of cancer. Methods: Patients diagnosed with at least one of 16 predefined cancers were recruited at four hospitals in three German cities. The effect of social care nurses' continuous involvement in acute oncology wards was measured by health-related quality of life (EORTC QLQ-C30), information and participation preferences, decisional conflicts, doctor-patient communication, health literacy and symptom perception. Absolute standardized mean difference was calculated as a standardized effect size to test baseline characteristics balance between the intervention and control groups. Results: The study enrolled 362 patients, 150 in the intervention and 212 in the control group. Except for gender, both groups differed in relevant socio-demographic characteristics, e.g. regarding age and educational background. With respect to the distribution of diagnoses, the intervention group showed a higher symptom burden than the control group. Moreover, the control group reported better quality of life at baseline compared to the intervention group (52.6 points (SD 21.7); 47.8 points (SD 22.0), ASMD = 0.218, p = 0.044). Conclusion: Overall, the intervention group showed more social and health vulnerability than the control group. Among other factors, the wide range of diagnoses included and structural variation between the recruiting clinics increased the risk for bias. We recommend a close, continuous monitoring of relevant social and health-related characteristics during the recruitment phase as well as the use of appropriate statistical analysis strategies for adjustment, such as propensity score methods