Semiparametric Multinomial Logit Models for Analysing Consumer Choice Behaviour

The multinomial logit model (MNL) is one of the most frequently used statistical models in marketing applications. It allows to relate an unordered categorical response variable, for example representing the choice of a brand, to a vector of covariates such as the price of the brand or variables characterising the consumer. In its classical form, all covariates enter in strictly parametric, linear form into the utility function of the MNL model. In this paper, we introduce semiparametric extensions, where smooth effects of continuous covariates are modelled by penalised splines. A mixed model representation of these penalised splines is employed to obtain estimates of the corresponding smoothing parameters, leading to a fully automated estimation procedure. To validate semiparametric models against parametric models, we utilise proper scoring rules and compare parametric and semiparametric approaches for a number of brand choice data sets

Employment and Growth in an Aging Society. A Simulation Study for Austria

In this study we use a long run macroeconomic model for Austria to simulate the effects of aging on employment, output growth, and the solvency of the social security system. By disaggregating the population into six age cohorts and modelling sex specific participation rates for each cohort, we are able to account for the future demographic trends. Apart from a baseline scenario, we perform three alternative simulations that highlight the effects of aging from different perspectives. These include (1) purely demographic developments, (2) increasing labour market imperfections, and (3) higher economic growth due to a productivity shock.Economic growth, Aging, Austria

Modelling the valuesphere and the ecosphere: Integrating the decision makers' perspectives into LCA

Methods for Life Cycle Impact Assessment have to cope with two critical aspects, the uncertainty in values and the (unknown) system behaviour. LCA methodology should cope explicitly with these subjective elements. A structured aggregation procedure is proposed that differentiates between the technosphere and the ecosphere and embeds them in the valuesphere. LCA thus becomes a decision support system that models and combines these three spheres. We introduce three structurally identical types of LCA, each based on one coherent but different set of values. These sets of values can be derived from the Cultural Theory and are labeled as ‘egalitarian', ‘individualistic', and ‘hierarchic'. Within Life Cycle Impact Assessment, a damage oriented assessment model is complemented with both a newly developed precautionary indicator designed to address unknown damage and an indicator for the manageability of environmental damages. The indicators for unknown damage and for manageability complete the set of indicators judged to be relevant by decision makers. The weights given to these indicators are also value-dependent. The framework proposed here answers the criticisms that present LCA methodology does not strictly enough separate subjective from objective elements and that it fails to accurately model environmental impact

A new polymorph of dimesitylborinic acid

A new polymorph of dimesitylborinic acid (or hydroxy­dimesitylborane), C18H23BO, showcasing different crystal packing and symmetry, complements the previously reported polymorph [Weese, Bartlett, Murray, Olmstead & Power (1987 ▶). Inorg. Chem. 26, 2409–2413; Entwistle, Batsanov & Marder (2007 ▶). Acta Cryst. E63, o2639–o2641]. The structure of the title compound contains only one mol­ecule in the asymmetric unit, and no O—H⋯O inter­actions are observed. However, mol­ecules are linked by weak inter­molecuar O—H⋯π(arene) inter­actions to form centrosymmetric dimers

Synthesis of a Trivalent P-Chloro-Dithienophosphole and its Reactivity with Organometallic Reagents

P-chloro-dithieno[3,2-b:2’,3’-d]phosphole was synthesized and isolated from the reaction of an aminophosphole and HCl. Developed to act as a common starting material for P-functionalized phospholes, the compound exhibits a surprising reactivitiy by generating dimeric biphospholes. Despite this apparent sensitivity, when reacting with organolithium and Grignard reagents, a series of differently P-functionalized dithieno[3,2-b:2’,3’-d]phospholes was accessible. Unexpectedly, organolithium reagents showed reduced reactivity with the chlorophosphole, limiting yields of the desired products due to the competing dimerization. Nonetheless, P- functionalized phospholes were isolated from reactions of the title compound with both Grignard and organolithium reagents in yields equivalent to, or higher, than by previous methods. A bithiophene- bridged bisphosphole system was also successfully synthesized without the necessity of generating a bis(dichlorophosphino) reagent. Finally, the isolated P-functionalized phospholes were analyzed for their photophysical properties. In general, these compounds are strong absorbers in the UV/visible range of the optical spectrum. The phospholes’ emissions were consistent with several previously reported, however, typically with low quantum yields.NSERC, CFI, CRC, Alberta Innovates - Technology Future

Virtual Reality and the Role of the Prefrontal Cortex in Adults and Children

In this review, the neural underpinnings of the experience of presence are outlined. Firstly, it is shown that presence is associated with activation of a distributed network, which includes the dorsal and ventral visual stream, the parietal cortex, the premotor cortex, mesial temporal areas, the brainstem and the thalamus. Secondly, the dorsolateral prefrontal cortex (DLPFC) is identified as a key node of the network as it modulates the activity of the network and the associated experience of presence. Thirdly, children lack the strong modulatory influence of the DLPFC on the network due to their unmatured frontal cortex. Fourthly, it is shown that presence-related measures are influenced by manipulating the activation in the DLPFC using transcranial direct current stimulation (tDCS) while participants are exposed to the virtual roller coaster ride. Finally, the findings are discussed in the context of current models explaining the experience of presence, the rubber hand illusion, and out-of-body experiences

Recommendations and illustrations for the evaluation of photonic random number generators

The never-ending quest to improve the security of digital information combined with recent improvements in hardware technology has caused the field of random number generation to undergo a fundamental shift from relying solely on pseudo-random algorithms to employing optical entropy sources. Despite these significant advances on the hardware side, commonly used statistical measures and evaluation practices remain ill-suited to understand or quantify the optical entropy that underlies physical random number generation. We review the state of the art in the evaluation of optical random number generation and recommend a new paradigm: quantifying entropy generation and understanding the physical limits of the optical sources of randomness. In order to do this, we advocate for the separation of the physical entropy source from deterministic post-processing in the evaluation of random number generators and for the explicit consideration of the impact of the measurement and digitization process on the rate of entropy production. We present the Cohen-Procaccia estimate of the entropy rate $h(\epsilon,\tau)$ as one way to do this. In order to provide an illustration of our recommendations, we apply the Cohen-Procaccia estimate as well as the entropy estimates from the new NIST draft standards for physical random number generators to evaluate and compare three common optical entropy sources: single photon time-of-arrival detection, chaotic lasers, and amplified spontaneous emission

Insights into the decontamination of cocaine-positive hair samples

A highly discussed step in hair sample preparation for forensic analytics is the applied decontamination. The here presented investigations aim to gain insight and give recommendations on how to conduct this decontamination for the analysis of cocaine consumption in hair. Key insights were gained from the investigation of cocaine consumer hair, which was artificially contaminated in a humid atmosphere with 13C6 labelled cocaine and from cocaine powder contaminated hair. Several decontamination protocols were investigated, whereby the usage of a decontamination protocol consisting of multiple short repetitive washes allowed to visualize the wash-out of (13C6-) cocaine. Multiple methanol washes proved to be an efficient and simple decontamination approach. Our findings showed that decontamination protocols can successfully wash-out recent cocaine contaminations. They were observed to be rather quickly washed-out, whereas cocaine from consumption or “older” cocaine contaminations were shown to eliminate both at a constant rate (from inner hair compartments). Thus, the usage of decontamination protocols to differentiate between consumption and contamination was shown to be limited. As contamination can happen any time at any level, only the application of elaborated decision trees, based on cocaine metabolite ratios and thresholds, can provide the distinction between consumption and contamination. Thus, the authors highly recommend the usage of such tools on all hair samples analyzed for cocaine consumption