Regularized Casimir energy for an infinite dielectric cylinder subject to light-velocity conservation

The Casimir energy of a dilute dielectric cylinder, with the same light-velocity as in its surrounding medium, is evaluated exactly to first order in $\xi^2$ and numerically to higher orders in $\xi^2$. The first part is carried out using addition formulas for Bessel functions, and no Debye expansions are required

Travel Routes and Spatial Abilities in Wild Chacma Baboons (Papio ursinus)

The primary objective of this research was to give insight into the spatial cognitive abilities of chacma baboons (Papio ursinus) and to address the question whether chacma baboons internally represent spatial information of large-scale space in the form of a so-called topological map or a Euclidean map. Navigating the environment using a topological map envisions that animals acquire, remember and integrate a set of interconnected pathways or route segments that are linked by frequently used landmarks or nodes, at which animals make travel decisions. When animals navigate using a Euclidean map, animals encode information in the form of true angles and distances in order to compute novel routes or shortcuts to reach out of view goals. Although findings of repeatedly used travel routes are generally considered evidence that animals possess topological-based spatial awareness, it is not necessarily evidence that they navigate (solely) using a topological map or lack complete Euclidean spatial representation. Therefore, three predictions from the hypothesised use of a topological map and Euclidean map were tested to distinguish between them. It was investigated whether there was a difference in travel linearity between the core area and the periphery of the home range, whether travel goals were approached from all directions or from one (or a few) distinct directions using the same approach routes and lastly, whether there was a difference between the initial leaving direction from a travel goal and the general direction towards the next goal. Data were collected during a 19-month period (04/2007-11/2008) at Lajuma research centre in the Soutpansberg (Limpopo Province, South Africa). A group of baboons were followed from their morning sleeping site to their evening sleeping site for 234 days, during which location records, behavioural data and important resource data were recorded. A statistical procedure termed the change-point test (CPT) was employed to identify locations at which baboons started orienting towards a goal and baboons showed goal-directed travel towards identified travel goals. Subsequently, hotspot analysis was employed to delineate clusters of such change-points, termed ‘decision hotspots’. Decision hotspots coincided with highly valuable resources, towards which baboons showed significantly faster travel. It thus seemed that they ‘knew’ when they were nearing their goals and adapted their speed accordingly. Decision hotspots were also located at navigational landmarks that delineated a network of repeatedly used travel routes characteristic of a topological map. Therewith, this method reveals an important utility to the study of decision-making by allowing a range of sites to be selected for detailed observations, which were previously limited to sleeping sites or ‘stop’ sites, which would be impossible if the decision hotspots had not been previously identified. Furthermore, baboons travelled as efficiently in the periphery as in the core area of their home range, which was suggested to be more consistent with Euclidean spatial awareness. However, comparatively low travel linearity throughout the home range revealed it is more likely that the baboons accumulated a similar knowledge of the periphery as of the core area, which allowed them to navigate with a similar efficiently through both areas. The mountainous terrain at the study site provided ample prominent landmarks to aid the baboons in navigation and allowed baboons to initiate navigation to a travel goal with the same direction as when they reached that goal. Baboons did not approach travel goals from all directions, but instead they approached their goals from the same direction(s). In conclusion, the findings of this research are more consistent with the use of a topological spatial representation of large scale space, where landmarks aid baboons to navigate efficiently through large scale space. A review of the literature shows that until date, evidence for the existence of Euclidean spatial representation in both animals and humans is extremely limited and often unconvincing. It is likely that a high level of experimental control is necessary to unambiguously demonstrate the existence of Euclidean spatial awareness in the future

A dynamical model of multicultural integration

In this dissertation, the conception, development, computer simulation and empirical testing of a dynamical model of multicultural integration are presented. The purpose of this model is to shed light on the dynamical social processes by which the beliefs and behaviors of individual people over time come to shape complex patterns of social relations in culturally plural societies. The model is primarily based on Berry’s model of acculturation, but goes beyond it in important ways, by including individual differences and allowing the representation of processes of individual change. First the assumptions of the model are examined by means of computer simulation and empirical testing. Then, the properties of the model are analyzed in detail with the help of three series of simulation studies of increasing complexity. Finally, large scale survey data are compared to some simulation results, and are used to place the dynamical model, and acculturation research in general, in a broader context

The factor structure of Lithuanian personality-descriptive adjectives of the highest frequency of use

We developed the Lithuanian taxonomy of personality traits according to the psycho-lexical approach. This was done in two studies. First, trait descriptive terms were selected from a Lithuanian dictionary. This selection led to a list of 435 personality-relevant adjectives was thus collected. This list was reduced to the more useful terms and ultimately led to the 194 most frequently used trait adjectives. Second, self-ratings from 212 participants were collected on both those 194 terms and on the 44-item BFI. Principal Components Analysis followed by Varimax rotation was applied on the collected ratings, and also on the ratings after ipsatization. For both these types of analysis structures with two up to seven factors were discussed. Each of the structures was also related to the five BFI-scales. The slightly clearer structure was found in the ipsatized ratings, in which clear support was found for the two-factor model (with Dynamism and Social Propriety), for the three-factor model (Dynamism, Affiliation and Order). A five-factor solution was fully presented with the Big Five factors Extraversion, Agreeableness and Conscientiousness and with a factor that had Intellect traits on the one pole and Neurotic traits on the other, and finally a factor called Toughness

Steady state model of a reheating furnace for determining slab boundary conditions

The slab reheating process in a reheating furnace is a very energy intensive process with many operating parameters that can be optimized. Numerical methods are therefore applied to generate models which can be used in an optimization strategy. This paper presents the first step in the creation of these models: obtaining the boundary conditions for the slab model from a steady state model of the furnace. The slab heating process itself is a transient phenomenon and an accurate cross-sectional slab temperature cannot be obtained using a steady state model. The furnace however, operates in a narrow range of temperatures and steady state operation is a suitable approximation. The steady state model is calibrated with data from a working reheating furnace at the ArcelorMittal Gent site. The numerical results show a good agreement with the experimental data with an average relative error of 3.1%. This gives confidence in using this model to determine the furnace heating boundary conditions of the slab model which will be implemented in future work

Visual BFI: an Exploratory Study for Image-based Personality Test

This paper positions and explores the topic of image-based personality test. Instead of responding to text-based questions, the subjects will be provided a set of "choose-your-favorite-image" visual questions. With the image options of each question belonging to the same concept, the subjects' personality traits are estimated by observing their preferences of images under several unique concepts. The solution to design such an image-based personality test consists of concept-question identification and image-option selection. We have presented a preliminary framework to regularize these two steps in this exploratory study. A demo version of the designed image-based personality test is available at http://www.visualbfi.org/. Subjective as well as objective evaluations have demonstrated the feasibility of image-based personality test in limited questions