Simplified specifications of a multivariate generalized autoregressive conditional heteroscedasticity model

Recent developments in multivariate volatility modeling suggest that the conditional correlation matrix can be described by a time series recursion, where the total number of parameters grows by the power-of-two of the dimension of financial returns. The power of two computational requirement makes high-dimensional multivariate volatility modeling very time consuming. In this paper, we propose two simplified specifications in a multivariate autoregressive conditional heteroscedasticity model. The first specification computes an unconditional correlation matrix from standardized residuals of the model. The second specification restricts the sum of the weights in a time-varying conditional correlation equation to be one. Applying a Bayesian sampling scheme allows the number of parameters to be reduced from the power of two of the dimension to the linear order of the dimension only and simultaneously provides us a framework for model comparison. We test our simplified specifications using simulated and real data from three sectoral indices in Hong Kong, three market indices and four exchange rates. The results suggest that our simplified specifications are more effective than the original formulation.     

How cues of what can be done in a virtual world influence learning: An affordance perspective

What we know about learning outcomes for collaborative tasks in virtual environments is a confusing set of results. Many organizations have been hesitant about their use of virtual environments for this reason. Virtual worlds (VWs) have received attention as environments for learning, yet little is known about their attributes, or how they affect learning in collaborative tasks. James Gibson proposed a theory of affordance to explain how cues in an environment are perceived and lead to some course of action. Based on his theory, we developed a model to describe how cues of what can be done in a VW influence learning. In doing so, we focused on the situativity afforded by VWs through context and social facilitation. We showed how VW artifacts and cues make it easier for users to understand the conditions and interactions in a VW.     

Atlas: Storing, updating and querying RDF(S) data on top of DHTs

The RDF(S) data model has been proposed for encoding metadata about Web resources. As more and more Web resources are annotated using RDF(S), there is an urgent need for efficiently dealing with this large volume of data. In this paper, we present Atlas, a peer-to-peer system for storing, updating and querying RDF(S) data. The Atlas system has been built using the distributed hash table Bamboo. Atlas was developed in the context of project OntoGrid, where it was used as a distributed repository for RDF(S) metadata describing Grid services and resources. The development of Atlas continues in other projects that our group participates currently. This paper gives an overview of the most recent version of Atlas and discusses a representative application.     

Decision-making in-socio and in-situ: Facilitation in virtual worlds

Past research suggests that “situatedness”, i.e. the context, as well as the social interaction that occurs within it, play an important role in cognitive processes such as learning and decision-making. Thus far, IT tools have been limited in the level and type of situatedness they facilitate. The advent of virtual worlds has changed this. Virtual worlds provide open, three-dimensional platforms for creating and designing real life-like spaces; they also allow for interaction between users in the form of “avatars” in that space. This research study focuses on virtual worlds as platforms for learning and decision-making. We propose a model that explains how individuals in a group learn and make decisions through a process that is influenced by the two unique characteristics of virtual worlds that enable situatedness: the facilitation for designing real life-like spaces, and the facilitation of rich many-to-many interactions.We draw on theories of situated cognition, social cognition, and flow to explicate the influence of these characteristics on the process of learning and decision-making. Data was collected by means of a quasi-experiment in Second Life (SL). Results from this study extend and validate the predictions of situated theories of decision-making within the context of a virtual world environment and suggest guidelines for practitioners who wish to use such environments to support organizational learning and decision-making. Perhaps the most compelling of these is to focus on maximizing the immersion of the individual in the activity by stimulating his or her perceptions of others and activity-related cues in the environment.     

Biomarker-Oriented Therapy in Bladder and Renal Cancer

Treatment of patients with urothelial carcinoma (UC) of the bladder or renal cancer has changed significantly during recent years and efforts towards biomarker-directed therapy are being investigated. Immune checkpoint inhibition (ICI) or fibroblast growth factor receptor (FGFR) directed therapy are being evaluated for non-muscle invasive bladder cancer (NMIBC) patients, as well as muscle-invasive bladder cancer (MIBC) patients. Meanwhile, efforts to predict tumor response to neoadjuvant chemotherapy (NAC) are still ongoing, and genomic biomarkers are being evaluated in prospective clinical trials. Currently, patients with metastatic UC (mUC) are usually treated with second-line ICI, while cisplatin-ineligible patients with programmed death-ligand 1 (PD-L1) positive tumors can benefit from first-line ICI. Platinum-relapsed UC patients harboring FGFR2/3 mutations can be treated with erdafitinib, while enfortumab vedotin has emerged as a novel third-line treatment option for mUC. In metastatic (clear cell) renal cell carcinoma (RCC), ICI was first introduced as second-line treatment after vascular endothelial growth factor receptor—tyrosine kinase inhibition (VEGFR-TKI). Currently, ICIs have also been introduced as first-line treatment in metastatic RCC. Although there is no evidence up to now for beneficial adjuvant treatment after surgery with VEGFR-TKIs in high-risk non-metastatic RCC, several trials are underway investigating the potential beneficial effect of ICIs in this setting.     

Phase separation in random copolymers from high conversion free radical copolymerization, 3

The effect of phase separation in chemically heterogeneous copolymers on the dynamic-mechanical data, i. e. the dynamic shear modulus and mechanical damping, was studied over a wide temperature range for the binary copolymer systems AN/MA, AN/VA, CHMA/MA and S/BA (AN: acrylonitrile, VA: vinyl acetate, CHMA: cyclohexyl methacrylate, MA: methyl acrylate, S: styrene, BA: n-butyl acrylate). Dynamic-mechanical tests are very sensitive to detect two coexisting phases within the chemically heterogeneous copolymers. Additionally, the morphology of the two-phase copolymers was investigated by transmission electron microscopy. Without exception, the studied copolymers show domain-matrix structures of dispersed rubber-like phases in the thermoplastic matrix. The domain sizes depend on the monomer reactivity ratios and the copolymer miscibility.     

Oxidation of Various Kraft Lignins with a Bacterial Laccase Enzyme

Modification of kraft lignin (KL), traditionally uses harsh and energy-demanding physical and chemical processes. In this study, the potential of the bacterial laccase CotA (spore coating protein A) for oxidation of KL under mild conditions was assessed. Thereby, the efficiency of CotA to oxidize both softwood and hardwood KL of varying purity at alkaline conditions was examined. For the respective type of wood, the highest oxidation activity by CotA was determined for the medium ash content softwood KL (MA_S) and the medium ash content hardwood KL (MA_H), respectively. By an up to 95% decrease in fluorescence and up to 65% in phenol content coupling of the structural lignin units was indicated. These results correlated with an increase in viscosity and molecular weight, which increased nearly 2 and 20-fold for MA_H and about 1.3 and 6.0-fold for MA_S, respectively. Thus, this study confirms that the CotA laccase can oxidize a variety of KL at alkaline conditions, while the origin and purity of KL were found to have a major impact on the efficiency of oxidation. Under the herein tested conditions, it was observed that the MA_H KL showed the highest susceptibility to CotA oxidation when compared to the other hardwood KLs and the softwood KLs. Therefore, this could be a viable method to produce sustainable resins and adhesives.     

Personality traits and concern for privacy: an empirical study in the context of location-based services

For more than a century, concern for privacy (CFP) has co-evolved with advances in information technology. The CFP refers to the anxious sense of interest that a person has because of various types of threats to the person's state of being free from intrusion. Research studies have validated this concept and identified its consequences. For example, research has shown that the CFP can have a negative influence on the adoption of information technology; but little is known about factors likely to influence such concern. This paper attempts to fill that gap. Because privacy is said to be a part of a more general ‘right to one's personality’, we consider the so-called ‘Big Five’ personality traits (agreeableness, extraversion, emotional stability, openness to experience, and conscientiousness) as factors that can influence privacy concerns. Protection motivation theory helps us to explain this influence in the context of an emerging pervasive technology: location-based services. Using a survey-based approach, we find that agreeableness, conscientiousness, and openness to experience each affect the CFP. These results have implications for the adoption, the design, and the marketing of highly personalized new technologies.     

Same situation--Different emotions: How appraisals shape our emotions.

Appraisal theories of emotion hold that it is the way a person interprets a situation--rather than the situation itself--that gives rise to one emotion rather than another emotion (or no emotion at all). Unfortunately, most prior tests of this foundational hypothesis have simultaneously varied situations and appraisals, making an evaluation of this assumption difficult. In the present study, participants responded to a standardized laboratory situation with a variety of different emotions. Appraisals predicted the intensity of individual emotions across participants. In addition, subgroups of participants with similar emotional response profiles made comparable appraisals. Together, these findings suggest that appraisals may be necessary and sufficient to determine different emotional reactions toward a particular situation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An automated high pressure capillary rheometer with hydraulic drive

A new capillary rheometer design is described, in which a hydraulic device is used to produce the pressure driving the sample fluid through capillaries. The device is fully automated and controlled by a PC unit. Various measuring modes can be preselected and are automatically executed. Some preliminary results with New tonian fluids and with polymer solutions show the functioning of the new rheometer.