Flow through and around groups of bodies

Fluid flows often consist of multiple bodies either filling most of the flow domain (for instance, porous media) or grouped in localized regions. Flow through localized groups containing many bodies has, hitherto, had little detailed study. The primary objective was to develop and trial new numerical and experimental procedures that make possible detail studies of complex multibody flows. The research investigates flow through a circular array of fixed size and populated by different numbers of equally spaced cylinders, allowing the void fraction (φ) to be varied. The main contribution is a detailed fully-resolved two-dimensional numerical calculation of flow past arrays containing from 1 to 133 cylinders, where the array Reynolds number is 2100. To produce this, a parallel computational code has been written, specifically for a supercomputer, in general object-orientated language using late binding and high performance numerical libraries (PETSc, MKL and ParaMETIS). New diagnostics were applied to understand the array’s influence on the flow through and around the array. A linear model was used to interpret the results. An experimental apparatus was designed to measure and vizualize the flow field and force contributions from an array fixed in a uniform flow. The design concept (including the flume, instrument array and electronics) was tested and optimized using CFD and FEA. The experimental results provide insight into the difference between two- and three-dimensional flow patterns. Case studies and experiments have generated data and graphical images at a level of resolution not previously possible. Three distinct regimes have been identified. For low φ, the interaction between the individual cylinders is weak. For intermediate φ, a shear layer is created and stabilized by the bleed flow through the group, resulting in steady forces on the group. For high φ, strong blocking occurs and the array acts like a solid cylinder

Numerical study of flow through and around a circular array of cylinders

This paper describes a study of the local and global effect of an isolated group of cylinders on an incident uniform flow. Using high resolution two-dimensional computations, we analysed the flow through and around a localised circular array of cylinders, where the ratio of array diameter (D-G) to cylinder diameter (D) is 21. The number of cylinders varied from N-C = 7 to 133, and they were arranged in a series of concentric rings to allow even distribution within the array with an average void fraction phi = N-C(D/DG)(2), which varied from 0.016 to 0.30. The characteristic Reynolds number of the array was Re-G = 2100. A range of diagnostic tools were applied, including the lift/drag forces on each cylinder (and the whole array), Eulerian and Lagrangian average velocity within the array, and the decay of maximum vorticity with distance downstream. To interpret the flow field, we used vorticity and the dimensionless form of the second invariant of the velocity gradient tensor. A mathematical model, based on representing the bodies as point forces, sources and dipoles, was applied to interpret the results. Three distinct flow regimes were identified. For low void fractions (phi 0.15), the array generates a wake in a similar way to a solid body of the same scale. For low void fraction arrays, the mathematical model provides a reasonable assessment of the forces on individual bodies within the array, the Eulerian mean velocity and the upstream velocity field. While it broadly captures the change in the rate of decay of the maximum vorticity magnitude Omega(max) downstream, the magnitude is underpredicted

Sexual Consent as Transcendence: A Phenomenological Understanding

Consent to sex is a topic of much research, particularly with the goal of optimizing sex education for youth, college students, and military service personnel. Sex educators have tended to err on the side of clear and concise definitions of consent for ease of instruction. However, the sexual science literature has steadily shown that the navigation of consent to sexuality activity is much more nuanced, situated and contextual. When consent is conceptualized as a yes or no answer to particular sexual acts or sexual activity altogether, it overlooks the dynamic nature of how people experience consenting. This article examines consent in the sexual science research literature and then considers these findings through the lens of some of the contributions of phenomenological philosophy. We then discuss the experience of consent as a dialogic process that can lead to moments of transcendence of the self and deep reverence for the other, despite some moments of lack of clarity or ambiguity within the same sexual act

Sexual Consent as Transcendence: A Phenomenological Understanding

Consent to sex is a topic of much research, particularly with the goal of optimizing sex education for youth, college students, and military service personnel. Sex educators have tended to err on the side of clear and concise definitions of consent for ease of instruction. However, the sexual science literature has steadily shown that the navigation of consent to sexuality activity is much more nuanced, situated and contextual. When consent is conceptualized as a yes or no answer to particular sexual acts or sexual activity altogether, it overlooks the dynamic nature of how people experience consenting. This article examines consent in the sexual science research literature and then considers these findings through the lens of some of the contributions of phenomenological philosophy. We then discuss the experience of consent as a dialogic process that can lead to moments of transcendence of the self and deep reverence for the other, despite some moments of lack of clarity or ambiguity within the same sexual act

Novel Distances for Dollo Data

We investigate distances on binary (presence/absence) data in the context of a Dollo process, where a trait can only arise once on a phylogenetic tree but may be lost many times. We introduce a novel distance, the Additive Dollo Distance (ADD), which is consistent for data generated under a Dollo model, and show that it has some useful theoretical properties including an intriguing link to the LogDet distance. Simulations of Dollo data are used to compare a number of binary distances including ADD, LogDet, Nei Li and some simple, but to our knowledge previously unstudied, variations on common binary distances. The simulations suggest that ADD outperforms other distances on Dollo data. Interestingly, we found that the LogDet distance performs poorly in the context of a Dollo process, which may have implications for its use in connection with conditioned genome reconstruction. We apply the ADD to two Diversity Arrays Technology (DArT) datasets, one that broadly covers Eucalyptus species and one that focuses on the Eucalyptus series Adnataria. We also reanalyse gene family presence/absence data on bacteria from the COG database and compare the results to previous phylogenies estimated using the conditioned genome reconstruction approach

The effect of partner-directed emotion in social exchange decision-making

Despite the prevalence of studies examining economic decision-making as a purely rational phenomenon, common sense suggests that emotions affect our decision-making particularly in a social context. To explore the influence of emotions on economic decision-making, we manipulated opponent-directed emotions prior to engaging participants in two social exchange decision-making games (the Trust Game and the Prisoner's Dilemma). Participants played both games with three different (fictional) partners and their tendency to defect was measured. Prior to playing each game, participants exchanged handwritten “essays” with their partners, and subsequently exchanged evaluations of each essay. The essays and evaluations, read by the participant, were designed to induce either anger, sympathy, or a neutral emotional response toward the confederate with whom they would then play the social exchange games. Galvanic skin conductance level (SCL) showed enhanced physiological arousal during anger induction compared to both the neutral and sympathy conditions. In both social exchange games, participants were most likely to defect against their partner after anger induction and least likely to defect after sympathy induction, with the neutral condition eliciting intermediate defection rates. This pattern was found to be strongest in participants exhibiting low cognitive control (as measured by a Go/no-Go task). The findings indicate that emotions felt toward another individual alter how one chooses to interact with them, and that this influence depends both on the specific emotion induced and the cognitive control of the individual

Long-term increase in growth of an estuarine predator, mulloway Argyrosomus japonicus, predicted to continue under future warming scenarios

Understanding the effects of climate change on fish biology and ecology is crucial for effective management of fisheries resources. Estuaries are warming at a faster rate than nearby oceans in south-eastern Australia, yet there is little understanding of how this may impact the growth of estuarine fish. We examined long-term changes and drivers of growth in an ecologically and economically important estuarine fish in this region, the mulloway Argyrosomus japonicus, using a growth chronology spanning 39 yr (1980−2018). The chronology was developed using 3112 otoliths collected over 12° of latitude. Mixed effects models identified a long-term increase in the growth rate of A. japonicus spanning nearly 3 decades in south-eastern Australia and a positive growth response to temperature. Temperature during the months of November−February best explained this growth response, likely representing a specific growing season for the species. However, there also remained some variation in growth not explained by increasing temperature over the period. We also found evidence of faster growth in individuals sampled at both younger and older ages, potentially caused by selectivity mechanisms. Regional climate forecasts predict that, based upon the observed response to temperature, the mean annual growth rate of A. japonicus in south-eastern Australia may increase by up to 8.9% by 2099. These results add to the growing body of literature demonstrating positive growth responses by marine species in warming environments and highlight the value of understanding the drivers of long-term growth variation in exploited fish stocks in order to predict future productivity under a range of environmental and fisheries management scenarios

Identificación de la estructura factorial óptima de la escala de resiliencia de Connor – Davidson en estudiantes universitarios chilenos y su comparación con una muestra de estudiantes universitarios españoles

54 p.La presente investigación se enmarca en la identificación de la estructura factorial óptima de la Escala de Resiliencia CD-RISC (Connor & Davidson, 2003), además de su validación en estudiantes universitarios chilenos, siendo ésta última de gran importancia debido a que es la primera validación de la escala en Chile. De igual forma, se realizará una comparación transcultural en base a una aplicación entre dos poblaciones hispanohablantes; una chilena y una española, de modo que permita esclarecer diferencias significativas frente a la misma aplicación. La primera se aplicó en 396 estudiantes universitarios, mientras que la segunda en 483. Se realizó un análisis factorial exploratorio a fin de determinar su estructura factorial concluyendo que la escala presenta una estructura unidimensional en ambas muestras. Pese a ello, no se pudo verificar la invarianza de medida del modelo unidimensional. En consecuencia, se estimó un modelo bifactor compuesto por un factor general y cinco específicos. En dicho modelo, una vez que se liberaron las cargas de los factores específicos, sí demostró invarianza fuerte entre ambas muestras. Se concluye la unidimensionalidad básica de la escala, además de señalar que únicamente el factor Espiritualidad toma peso como factor específico más allá del factor general de resiliencia

The Use of a Scoring System to Guide Thromboprophylaxis in a High-Risk Pregnant Population

Guidelines for thromboprophylaxis in pregnancy are usually based upon clinical observations and expert opinion. For optimal impact, their use must be attended by consistency in the advice given to women. In this observational study, we evaluated the performance of a scoring system, used as a guide for clinicians administering dalteparin to pregnant women at increased risk of venous thromboembolism. The work included 47 women treated with dalteparin prior to adoption of the scoring system and 58 women treated with dalteparin after its adoption. The indication for thromboprophylaxis was recorded in each case together with details of the regimen employed, obstetric, and haematological outcomes. The main outcome measure was to determine whether consistency improved after adoption of the scoring system. We also recorded the occurrence of any new venous thromboembolism, haemorrhage, the use of regional anaesthesia during labour, evidence of allergy, and thrombocytopenia. We found that use of the scoring system improved the consistency of advice and increased the mean duration of thromboprophylaxis. None of the subjects suffered venous thromboembolism after assessment using the scoring system. There was no increase in obstetric or anaesthetic morbidity when dalteparin was given antenatally period and no evidence of heparin-induced thrombocytopenia