Use of the Metropolis-Hastings Algorithm in the Calibration of a Patient Level Simulation of Prostate Cancer Screening

Designing cancer screening programmes requires an understanding of epidemiology, disease natural history and screening test characteristics. Many of these aspects of the decision problem are unobservable and data can only tell us about their joint uncertainty. A Metropolis-Hastings algorithm was used to calibrate a patient level simulation model of the natural history of prostate cancer to national cancer registry and international trial data. This method correctly represents the joint uncertainty amongst the model parameters by drawing efficiently from a high dimensional correlated parameter space. The calibration approach estimates the probability of developing prostate cancer, the rate of disease progression and sensitivity of the screening test. This is then used to estimate the impact of prostate cancer screening in the UK. This case study demonstrates that the Metropolis-Hastings approach to calibration can be used to appropriately characterise the uncertainty alongside computationally expensive simulation models

Multi-Channel Choice in Retail Banking Services: Exploring the Role of Service Characteristics

Companies are moving towards omni-channel management offering all products and services on all channels. Yet, some of these investments might be obsolete as certain products are associated with certain channels. At this point, service companies are still left behind as past research focused on product categories and it remains unclear if the results are transferrable to services. Our study addresses this gap by analyzing the influence of service characteristics on channel choice. We tested our research model by surveying 2,000 banking customers in Germany on their past channel choices for five financial services. The results show that complex services with a high value are rather purchased in a branch than the online channel. Thereby, demographics and behavior-related constructs are important control variables. The results improve the understanding of channel choice behavior in a multi-channel context for services and provide guidance for practitioners to right-channel IT investments

Determinants of Multi-Channel Behavior: Exploring Avenues for Future Research in the Services Industry

The rise of new technologies has led companies to offer their products and services on multiple channels. This has turned consumers into multi-channel shoppers and rendered their channel choice unpredictable. Yet, a thorough understanding of multi-channel behavior is needed to influence it appropriately. We conducted a systematic literature review on the determinants of multi-channel behavior with a focus on services, and numerically assessed the research frequency of each behavioral influence. Our results show that multi-channel behavior is influenced by the stage of the buying process, the channel characteristics, the consumer attributes and the product category. Moreover, we discovered that services are under-researched compared to the retail sector. Based on these under-researched areas, we derive three research questions that enhance the knowledge on multi-channel behavior in the service industry. Further, we offer an outlook for an upcoming laboratory experiment

A cost-effectiveness model of prostate cancer screening

Prostate cancer is the second most common cause of male cancer death in the UK, however due to the uncertainty around the health benefits and cost-effectiveness of a national screening programme, organised screening has not been adopted. A cost-effectiveness analysis was therefore conducted to examine the impact of a national prostate cancer screening programme on behalf of the UK National Screening Committee. A discrete event simulation model was developed to evaluate the use of the prostate specific antigen (PSA) blood test as a screening tool in the UK. The model comprises four parts: a disease natural history model which models the underlying disease itself; a calibration module which enables unobservable model parameters to be calibrated to observable data using a Metropolis-Hastings algorithm; a screening component which allows different screening options to be imposed on the population; and a resource impact model which calculates the resource implications of the alternative screening options. The model estimates incidence, lead time, over-detection, quality of life years (QALYs), mortality and resource implications of single and repeat screening strategies

DESIGNING ADAPTIVE NUDGES FOR MULTI-CHANNEL CHOICES OF DIGITAL SERVICES: A LABORATORY EXPERIMENT DESIGN

Channel-switching, cross-channel free-riding, and research shopping is causing problems for companies offering multiple channels. Either customers could choose a channel that is more expensive for the company or they inform themselves in one channel but switch to a competitor for the final purchase. We aim to influence channel choice by using the recently proposed IS concept of digital nudging. In particular, we leverage the nudges of social norms and perceived risk in the online channel. In addition to this concept, we propose that the individual context of the user, like gender or personality, has to be incorporated as a moderator by designing customer specific (i.e. adaptive) nudges. To test these hypotheses, we outline an experiment design for a lab experiment and show how multi-channel choices can be influenced with design interventions in the form of nudges. As previous studies have only tested static nudges, we contribute to existing research by enhancing the nudge theory to adaptively consider user characteristics. Moreover, we apply the nudge theory to the new context of multi-channel choices. Finally, we provide guidance for practitioners on designing their own online channels

Continuum Halos in Nearby Galaxies -- an EVLA Survey (CHANG-ES) -- II: First Results on NGC 4631

We present the first results from the CHANG-ES survey, a new survey of 35 edge-on galaxies to search for both in-disk as well as extra-planar radio continuum emission. The motivation and science case for the survey are presented in a companion paper (Paper I). In this paper (Paper II), we outline the observations and data reduction steps required for wide-band calibration and mapping of EVLA data, including polarization, based on C-array test observations of NGC 4631. With modest on-source observing times (30 minutes at 1.5 GHz and 75 minutes at 6 GHz for the test data) we have achieved best rms noise levels of 22 and 3.5 $\mu$Jy beam$^{-1}$ at 1.5 GHz and 6 GHz, respectively. New disk-halo features have been detected, among them two at 1.5 GHz that appear as loops in projection. We present the first 1.5 GHz spectral index map of NGC 4631 to be formed from a single wide-band observation in a single array configuration. This map represents tangent slopes to the intensities within the band centered at 1.5 GHz, rather than fits across widely separated frequencies as has been done in the past and is also the highest spatial resolution spectral index map yet presented for this galaxy. The average spectral index in the disk is $\bar\alpha_{1.5 GHz}\,=\,-0.84\,\pm\,0.05$ indicating that the emission is largely non-thermal, but a small global thermal contribution is sufficient to explain a positive curvature term in the spectral index over the band. Two specific star forming regions have spectral indices that are consistent with thermal emission. Polarization results (uncorrected for internal Faraday rotation) are consistent with previous observations and also reveal some new features. On broad scales, we find strong support for the notion that magnetic fields constrain the X-ray emitting hot gas.Comment: Accepted to the Astronomical Journal, Version 2 changes: Added acknowledgement to NRA

Effects of manganese exposure on olfactory functions in teenagers: A pilot study

Long-term exposure to environmental manganese (Mn) affects not only attention and neuromotor functions but also olfactory functions of a pre-adolescent local population who have spent their whole life span in contaminated areas. In order to investigate the effect of such exposure at the level of the central nervous system we set up a pilot fMRI experiment pointing at differences of brain activities between a non-exposed population (nine subjects) and an exposed one (three subjects). We also measured the volume of the olfactory bulb as well as the identification of standard olfactory stimuli. Our results suggest that young subjects exposed to Mn exhibit a reduction of BOLD signal, subjective odor sensitivity and olfactory bulb volume. Moreover a region of interest SPM analysis showed a specifically reduced response of the limbic system in relation to Mn exposure, suggesting an alteration of the brain network dealing with emotional responses

Continuum Halos in Nearby Galaxies -- an EVLA Survey (CHANG-ES) -- I: Introduction to the Survey

We introduce a new survey to map the radio continuum halos of a sample of 35 edge-on spiral galaxies at 1.5 GHz and 6 GHz in all polarization products. The survey is exploiting the new wide bandwidth capabilities of the Karl G. Jansky Very Large Array (i.e. the Expanded Very Large Array, or EVLA) in a variety of array configurations (B, C, and D) in order to compile the most comprehensive data set yet obtained for the study of radio halo properties. This is the first survey of radio halos to include all polarization products. In this first paper, we outline the scientific motivation of the survey, the specific science goals, and the expected improvements in noise levels and spatial coverage from the survey. Our goals include investigating the physical conditions and origin of halos, characterizing cosmic ray transport and wind speed, measuring Faraday rotation and mapping the magnetic field, probing the in-disk and extraplanar far-infrared - radio continuum relation, and reconciling non-thermal radio emission with high-energy gamma-ray models. The sample size allows us to search for correlations between radio halos and other properties, including environment, star formation rate, and the presence of AGNs. In a companion paper (Paper II) we outline the data reduction steps and present the first results of the survey for the galaxy, NGC 4631.Comment: 17 pages, 1 figure, accepted to the Astronomical Journal, Version 2 changes: added acknowledgement to NRA

Discovery and Validation of Novel Biomarkers for Detection of Epithelial Ovarian Cancer

Detection of epithelial ovarian cancer (EOC) poses a critical medical challenge. However, novel biomarkers for diagnosis remain to be discovered. Therefore, innovative approaches are of the utmost importance for patient outcome. Here, we present a concept for blood-based biomarker discovery, investigating both epithelial and specifically stromal compartments, which have been neglected in search for novel candidates. We queried gene expression profiles of EOC including microdissected epithelium and adjacent stroma from benign and malignant tumours. Genes significantly differentially expressed within either the epithelial or the stromal compartments were retrieved. The expression of genes whose products are secreted yet absent in the blood of healthy donors were validated in tissue and blood from patients with pelvic mass by NanoString analysis. Results were confirmed by the comprehensive gene expression database, CSIOVDB (Ovarian cancer database of Cancer Science Institute Singapore). The top 25% of candidate genes were explored for their biomarker potential, and twelve were able to discriminate between benign and malignant tumours on transcript levels (p < 0.05). Among them T-cell differentiation protein myelin and lymphocyte (MAL), aurora kinase A (AURKA), stroma-derived candidates versican (VCAN), and syndecan-3 (SDC), which performed significantly better than the recently reported biomarker fibroblast growth factor 18 (FGF18) to discern malignant from benign conditions. Furthermore, elevated MAL and AURKA expression levels correlated significantly with a poor prognosis. We identified promising novel candidates and found the stroma of EOC to be a suitable compartment for biomarker discovery

SCAMPI: Service platform for soCial Aware Mobile and Pervasive computIng

Allowing mobile users to find and access resources available in the surrounding environment opportunistically via their smart devices could enable them to create and use a rich set of services. Such services can go well beyond what is possible for a mobile phone acting alone. In essense, access to diverse resources such as raw computational power, social networking relationships, or sensor readings across a set of different devices calls for distributed task execution. In this paper, we discuss the SCAMPI architecture designed to support distributed task execution in opportunistic pervasive networks. The key elements of the architecture include leveraging human social behavior for efficient opportunistic interaction between a variety of sensors, personal communication devices and resources embedded in the local environment. The SCAMPI architecture abstracts resources asservice components following a service-oriented model. This enables composing rich applications that utilize a collection of service components available in the environment