Algebraically special coplanar shear-free perfect fluids in general relativity

We investigate all algebraically special, not conformally flat, shear-free, isentropic (p(w), w + p ≠ 0), perfect fluid solutions of Einstein's field equations. We show, using the GHP formalism, that if the repeated principle null direction of the Weyl tensor is coplanar with the fluid's 4-velocity and vorticity vector (assumed nonzero), then the fluid's expansion must vanish.

Who thinks I need a perfect body? Perceptions and internal dialogue among adolescents about their bodies

The main aim of this study was to provide a detailed examination of the nature of the messages that adolescent boys and girls receive about their bodies. Forty adolescent boys and 40 adolescent girls participated in an in-depth interview to gain an understanding of the range of potential ‘sources’ of body-related messages. Messages were organized around the source of these messages (self, mother, father, brother, sister, female friends, male friends, media). There were consistent gender differences in the way that adolescents received and interpreted messages about their bodies. Overall girls received more positive and more negative messages than boys did. Boys reported having received virtually no negative messages from most people. The content of internal dialogue among adolescents revealed that messages about the body could be interpreted, distorted, and deflected. The implications of these findings for preventing body image-related problems and disordered eating among adolescents are discussed.

Shear- free perfect fluids with solenoidal magnetic curvature and a γ-law equation of state

We show that shear-free perfect fluids obeying an equation of state p = (γ − 1)μ are non-rotating or non-expanding under the assumption that the spatial divergence of the magnetic part of the Weyl tensor is zero.

The outlier phenomenon in entrepreneurship and economic growth : mollycoddling policies create New Zealand’s perfect storm

Analyzing GEM 2005 data, we confirm that entrepreneurship and economic development form a U-shaped curve. We seek to understand New Zealand’s large deviation from the modeled curve by factor-analyzing all countries’ deviations from the curve. We make recommendations that would move New Zealand toward the trend line and thus aid in increasing its level of economic development. Our findings indicate that measures that overprotect workers, spoil incentives, or indulge welfare passivity can stymie economic growth even in conditions of high entrepreneurial activity.

Building the perfect beast : scientific romance and Jewish representations 1880-1914

Various cultural mediums portrayed Jews in Britain in the late Victorian and Edwardian periods. Scientific romance harnessed past communicative 'discourses' such as history, folklore, theology, and mythology and was an innovative form of literature that heralded a new era in the construction of Jewish identity between 1880 to 1914.

Symbolic computation and perfect fluids in general relativity

Focuses on two areas within the field of general relativity. Firstly, the history and implications of the long-standing conjecture that general relativistic, shear-free perfect fluids which obey a barotropic equation of state p = p(w) such that w + p = 0, are either non-expanding or non-rotating. Secondly the application of the computer algebra system Maple to the area of tetrad formalisms in general relativity.

New Zealand's perfect storm of entrepreneurship and economic development

Applying a grounded-theory approach to analyzing the Global Entrepreneurship Monitor (GEM) data, we attempt to explain why New Zealand exhibits only a moderate level of economic development despite its high level of entrepreneurship. By statistically analyzing why 34 other countries in the 2005 GEM dataset exhibit small deviations from the classical quadratic curvilinear relationship between entrepreneurship and economic development, we develop a better understanding of the entrepreneurial framework conditions underlying New Zealand’s large deviation from this trend line. Based on our findings from the GEM data we make policy recommendations that could aid in moving New Zealand (and other countries) closer toward the trend line and thus promote economic development.

Shear-free perfect fluids with a solenoidal magnetic curvature

We investigate shear-free perfect fluid solutions of the Einstein field equations where the fluid pressure satisfies a barotropic equation of state and the spatial divergence of the magnetic part of the Weyl tensor is zero. We prove, with the exception of certain quite restricted special cases within the class of solutions in which there exists a Killing vector aligned with the vorticity and for which the magnitude of the vorticity ω is not a function of the matter density μ alone, that such a fluid is either non-rotating or non-expanding. In the restricted cases the equation of state must satisfy an over-determined differential system.

Efficient web browsing with perfect anonymity using page prefetching

Anonymous web browsing is a hot topic with many potential applications for privacy reasons. The current dominant strategy to achieve anonymity is packet padding with dummy packets as cover traffic. However, this method introduces extra bandwidth cost and extra delay. Therefore, it is not practical for anonymous web browsing applications. In order to solve this problem, we propose to use the predicted web pages that users are going to access as the cover traffic rather than dummy packets. Moreover, we defined anonymity level as a metric to measure anonymity degrees, and established a mathematical model for anonymity systems, and transformed the anonymous communication problem into an optimization problem. As a result, users can find tradeoffs among anonymity level and cost. With the proposed model, we can describe and compare our proposal and the previous schemas in a theoretical style. The preliminary experiments on the real data set showed the huge potential of the proposed strategy in terms of resource saving.

Shear-free perfect fluids with a solenoidal electric curvature

We prove that the vorticity or the expansion vanishes for any shear-free perfect fluid solution of the Einstein field equations where the pressure satisfies a barotropic equation of state and the spatial divergence of the electric part of the Weyl tensor is zero.

Does practice make perfect? Results from a Chinese feasibility study of cognitive remediation in schizophrenia

Patients with schizophrenia often receive little by way of non-pharmacological interventions. Despite this, promising outcomes in programmes targeting cognitive deficits have been reported, suggesting that this is an area worthy of further investigation. The aim of the study was to implement and evaluate a brief computerised cognitive remediation programme designed to improve memory and attention in a male Chinese sample with chronic schizophrenia. Pre-testing was completed on a number of clinical and cognitive measures for intervention (n = 14) and treatment as usual (n = 17) participants. The intervention group then completed six weeks ( x no. of sessions = 12.78) of the computer-based cognitive remediation programme. Post-test measures for both groups were then collected again. Following the six week intervention, we found, contrary to our expectations, the intervention group improved on several of the clinical variables. The intervention group also performed better than the control group on the post-test measure of attention, but not verbal memory. These findings suggest that it is feasible to improve some aspects of cognitive abilities with a simple computerised training programme for people with serious mental illness.