Stability and Vortex Shedding of Bluff Body Arrays

The primary purpose of this study was to develop an understanding of the stability of laminar flow through bluff body arrays, and investigate the nature of the unsteady vortex shedding regime that follows. The flow was numerically investigated using a specially developed multi-domain spectral element solver. Important criteria in the solver development were flexibility, efficiency, and accuracy. Flexibility was critical to the functionality of the code, as arrays of varying geometry were investigated. Efficiency with a high degree of accuracy was also of primary importance, with the code implemented to run efficiently on today's massively parallel architectures. Numerical two-dimensional stability analysis of the flow in several configurations of inline and staggered array geometries was performed. The growth rate, eigenfunction, and frequency of the disturbances were determined. The critical Reynolds number for flow transition in each case was identified and compared to that of flow over a single body. Based on the solutions of the laminar flow, a one-dimensional analytical analysis was performed on selected velocity profiles in the wake region. The results of this analysis were used to guide the interpretation of the two dimensional results and formulate a general theory of stability of inline and staggered bluff body arrays. The nature of the flow in the unsteady regime following the onset of instability was examined for an inline and a staggered arrangement. Particular attention was focused on the vortex shedding which was visualized and quantified through computation of the flow swirl, a quantity which identifies regions of rotary motion. The conditions required for the generation of leading edge vortex shedding were identified and discussed. Finally, a third geometry related to the inline and staggered arrays was considered. Flow solution data for this geometry is presented and its suitability as a model for louvered arrays was discussed.Air Conditioning and Refrigeration Project 11

Quantum incompressibility of a falling Rydberg atom, and a gravitationally-induced charge separation effect in superconducting systems

Freely falling point-like objects converge towards the center of the Earth. Hence the gravitational field of the Earth is inhomogeneous, and possesses a tidal component. The free fall of an extended quantum object such as a hydrogen atom prepared in a high principal-quantum-number stretch state, i.e., a circular Rydberg atom, is predicted to fall more slowly that a classical point-like object, when both objects are dropped from the same height from above the Earth. This indicates that, apart from "quantum jumps," the atom exhibits a kind of "quantum incompressibility" during free fall in inhomogeneous, tidal gravitational fields like those of the Earth. A superconducting ring-like system with a persistent current circulating around it behaves like the circular Rydberg atom during free fall. Like the electronic wavefunction of the freely falling atom, the Cooper-pair wavefunction is "quantum incompressible." The ions of the ionic lattice of the superconductor, however, are not "quantum incompressible," since they do not possess a globally coherent quantum phase. The resulting difference during free fall in the response of the nonlocalizable Cooper pairs of electrons and the localizable ions to inhomogeneous gravitational fields is predicted to lead to a charge separation effect, which in turn leads to a large repulsive Coulomb force that opposes the convergence caused by the tidal, attractive gravitational force on the superconducting system. A "Cavendish-like" experiment is proposed for observing the charge separation effect induced by inhomogeneous gravitational fields in a superconducting circuit. This experiment would demonstrate the existence of a novel coupling between gravity and electricity via macroscopically coherent quantum matter.Comment: `2nd Vienna Symposium for the Foundations of Modern Physics' Festschrift MS for Foundations of Physic

The Legacy of ERA, Privatization and the Policy Ratchet

This article explores the ways in which the neo-liberal impetus toward the privatization of state schooling signalled in the Education Reform Act 1988 (ERA) has become embedded in the English school system. Four main points are made. First, that ERA itself was of huge strategic rather than substantive importance as far as privatization is concerned. Second, by tracing the lineage of privatization from ERA onwards a 'ratchet' effect of small and incremental policy moves can be identified, which have disseminated, embedded and naturalized privatization within public sector provision. Third, that while privatization has been taken up and taken much further by New Labour than it had been by the Conservatives there are differences between the two sets of governments in the role of privatization in education policy and the role of the state. Fourth, the participation of private providers in the planning and delivery of state services has put the private sector at the very heart of policy. At points the article draws upon interviews conducted with private sector providers. © 2008 Sage Publications

Linking Protection with the Distribution of Grouper and Habitat Quality in Seychelles

Marine protected areas can be designated for a number of reasons, but exactly how they provide benefits is only recently being understood. We assessed the effect of protection on the size and distribution of six common species of grouper in a coral reef ecosystem. Data on live coral cover, coral genus diversity, and coral colony structure type were also compared to give an indication of reef quality between sites. A significant interaction was found for Aethaloperca rogaa and, Cephalopholis nigripinni, indicating that protected areas held greater numbers of smaller and median sized fish of these species than unprotected areas. Similar but nonsignificant trends were found for Cephalopholis miniata and Cephalopholis argus.For Anyperodon leucogrammicus,MPAs held significantly more fish than unprotected sites,but as the increase was equal between size categories there was no interaction.The last species Epinephelus fasciatus, which was one of the smallest species, had no significant interaction, similar mean counts between protected and unprotected areas, and no obvious strong favouritism for particular sites with values indicating better reef quality, indicating intraspecies competition. The results of this study indicate that while the MPAs in this study are likely too small to benefit large groupers, the improvements to habitat quality have indirect benefits to groupers, especially at their earlier life stages

4D, N = 1 Supersymmetry Genomics (I)

Presented in this paper the nature of the supersymmetrical representation theory behind 4D, N = 1 theories, as described by component fields, is investigated using the tools of Adinkras and Garden Algebras. A survey of familiar matter multiplets using these techniques reveals they are described by two fundamental valise Adinkras that are given the names of the cis-Valise (c-V) and the trans-Valise (t-V). A conjecture is made that all off-shell 4D, N = 1 component descriptions of supermultiplets are associated with two integers - the numbers of c-V and t-V Adinkras that occur in the representation.Comment: 53 pages, 19 figures, Report-II of SSTPRS 2008 Added another chapter for clarificatio

Making things happen : a model of proactive motivation

Being proactive is about making things happen, anticipating and preventing problems, and seizing opportunities. It involves self-initiated efforts to bring about change in the work environment and/or oneself to achieve a different future. The authors develop existing perspectives on this topic by identifying proactivity as a goal-driven process involving both the setting of a proactive goal (proactive goal generation) and striving to achieve that proactive goal (proactive goal striving). The authors identify a range of proactive goals that individuals can pursue in organizations. These vary on two dimensions: the future they aim to bring about (achieving a better personal fit within one’s work environment, improving the organization’s internal functioning, or enhancing the organization’s strategic fit with its environment) and whether the self or situation is being changed. The authors then identify “can do,” “reason to,” and “energized to” motivational states that prompt proactive goal generation and sustain goal striving. Can do motivation arises from perceptions of self-efficacy, control, and (low) cost. Reason to motivation relates to why someone is proactive, including reasons flowing from intrinsic, integrated, and identified motivation. Energized to motivation refers to activated positive affective states that prompt proactive goal processes. The authors suggest more distal antecedents, including individual differences (e.g., personality, values, knowledge and ability) as well as contextual variations in leadership, work design, and interpersonal climate, that influence the proactive motivational states and thereby boost or inhibit proactive goal processes. Finally, the authors summarize priorities for future researc

The yellow European eel (Anguilla anguilla L.) may adopt a sedentary lifestyle in inland freshwaters

We analysed the movements of the growing yellow phase using a long-term mark–recapture programme on European eels in a small catchment (the Frémur, France). The results showed that of the yellow eels (>200 mm) recaptured, more than 90% were recaptured at the original marking site over a long period before the silvering metamorphosis and downstream migration. We conclude that yellow European eels >200 mm may adopt a sedentary lifestyle in freshwater area, especially in small catchment

Prognostic value of B cells in cutaneous melanoma

Background: Measures of the adaptive immune response have prognostic and predictive associations in melanoma and other cancer types. Specifically, intratumoral T cell density and function have considerable prognostic and predictive value in skin cutaneous melanoma (SKCM). Less is known about the significance of tumor-infiltrating B cells in SKCM. Our goal was to understand the prognostic and predictive value of B cell phenotypic subsets in SKCM using RNA sequencing. Methods: We used our previously published algorithm, V'DJer, to assemble B cell receptor (BCR) repertoires and estimate diversity from short-read RNA sequencing (RNA-seq). We applied machine learning-based cellular phenotype classifiers to measure relative similarity of bulk tumor sample gene expression profiles and different B cell phenotypes. We assessed these aspects of B cell biology in 473 SKCM from the Cancer Genome Atlas Project (TCGA) as well as in RNA-seq data corresponding to tumor samples procured from patients who received CTLA-4 and PD-1 inhibitors for metastatic SKCM. Results: We found that the BCR repertoire was associated with different clinical factors, such as tumor tissue site and sex. However, increased clonality of the BCR repertoire was favorably prognostic in SKCM and was prognostic even after first conditioning on various clinical factors. Mutation burden was not correlated with any BCR measurement, and no specific mutation had an altered BCR repertoire. Lack of an assembled BCR in pre-treatment tumor tissues was associated with a lack of anti-tumor response to a CTLA-4 inhibitor in metastatic SKCM. Conclusions: These findings suggest an important prognostic and predictive role for B cell characteristics in SKCM. This has implications for melanoma immunobiology and potential development of immunogenomics features to predict survival and response to immunotherapy