bluuebunny/crossref_metadata_2025_split huggingface dataset:
A simplified vortex model of propeller and wind-turbine wakes
Authors: Segalini Antonio , Alfredsson P. Henrik 
Published: May 2013

AbstractA new vortex model of inviscid propeller and wind-turbine wakes is proposed based on an asymptotic expansion of the Biot–Savart induction law to account for the finite vortex core size. The circulation along the blade is assumed to be constant from the blade root to the tip approximating a turbine with maximum power production for given operating conditions. The model iteratively calculates the tip-vortex path, allowing the wake to expand/contract freely, and is afterward able to evaluate the velocity field in the whole domain. The ‘roller-bearing analogy’, proposed by Okulov and Sørensen (J. Fluid Mech., vol. 649, 2010, pp. 497–508), is used to determine the vortex core size. A comparison of the main outcomes of the present model with the general momentum theory is performed in terms of the operating parameters (namely the number of blades, the tip-speed ratio, the blade circulation and the vortex core size), demonstrating good agreement between the two. Furthermore, experimental data have been compared with the model outputs to validate the model under real operating conditions.
A note on relative equilibria in a rotating shallow water layer
Authors: Ait Abderrahmane Hamid , Fayed Mohamed , Ng Hoi Dick , Vatistas Georgios H. 
Published: May 2013

AbstractRelative equilibria of two and three satellite vortices in a rotating shallow water layer have been recorded via particle image velocimetry (PIV) and their autorotation speed was estimated. This study shows that these equilibria retain the fundamental characteristics of Kelvin’s equilibria, and could be adequately described by the classical idealized point vortex theory. The same conclusion can also be inferred using the experimental dataset of Bergmann et al. (J. Fluid Mech., vol. 679, 2011, pp. 415–431; J. Fluid Mech., vol. 691, 2012, pp. 605–606) if the assigned field’s contribution to pattern rotation is included.
Experimental Study on Aerodynamics of Micro-Wind Turbines with Large-Tip non-Twisted Blades
Authors: Chen T. Y. , Hung C. W. , Liao Y. T. 
Published: May 2013

AbstractThis research experimentally investigates the rotor aerodynamics of horizontal-axis, micro-wind turbines. Specifically, the aerodynamic characteristics of large-tip, non-twisted blades are studied. The study is conducted in a wind tunnel system to obtain the relations between the power coefficient (CP) and tip speed ratio (TSR), the torque coefficient (CT) and TSR. Effects of rotor position inside a flanged diffuser, rotor solidity and blade number on rotor performance are investigated. The blade cross-section is NACA4415 airfoil. The pitch angle of the blades is fixed at 30°, and the chord length ratio between the blade root and tip (Cr / Ct) is fixed at 0.3. Results show that larger power output is obtained when the rotor placed closer to the diffuser inlet. The 60%-solidity rotor, in general, achieves better power and torque outputs among the test rotor solidities. The higher the blade number is, the larger the power output is, but the difference is small. Comparisons between the present and previous relatively short-tip blades (Cr / Ct = 0.5) show that the present blades have better power and torque outputs at lower rotor rotational speed. These results suggest that the large-tip blades are suitable for micro-wind turbine applications, and make rotor-generator matching more flexible.
Daggers in the West: Early Bronze Age Daggers and Knives in the South-west Peninsula
Authors: Jones Andy M. , Quinnell Henrietta 
Published: May 2013

This paper describes the results from a project to date Early Bronze Age daggers and knives from barrows in south-west England. Copper alloy daggers are found in the earliest Beaker associated graves and continue to accompany human remains until the end of the Early Bronze Age. They have been identified as key markers of Early Bronze Age graves since the earliest antiquarian excavations and typological sequences have been suggested to provide dating for the graves in which they are found. However, comparatively few southern British daggers are associated with radiocarbon determinations. To help address this problem, five sites in south-west England sites were identified which had daggers and knives, four of copper alloy and one of flint, and associated cremated bone for radiocarbon dating. Three sites were identified in Cornwall (Fore Down, Rosecliston, Pelynt) and two in Devon (Upton Pyne and Huntshaw). Ten samples from these sites were submitted for radiocarbon dating. All but one (Upton Pyne) are associated with two or more dates. The resulting radiocarbon determinations revealed that daggers/knives were occasionally deposited in barrow-associated contexts in the south-west from c. 1900 to 1500 calbc.The dagger at Huntshaw, Devon, was of Camerton-Snowshill type and the dates were earlier than those generally proposed but similar to that obtained from cremated bone found with another dagger of this type from Cowleaze in Dorset: these dates may necessitate reconsideration of the chronology of these daggers
SOCIAL HISTORY, BIOLOGY, AND THE EMERGENCE OF HIV IN COLONIAL AFRICA
Authors: Giles-Vernick Tamara , Gondola Ch. Didier , Lachenal Guillaume , Schneider William H. 
Published: May 2013

AbstractThis essay considers how historians of Africa can draw from and critically contribute to biomedical debates. Recent virological research has established that the HIV/AIDS pandemic began with the passage of simian immunodeficiency viruses into human populations in the first half of the twentieth century. Current debates on the emergence of HIV are an opportunity for historians to engage with biomedical research to rethink social, political, and environmental histories of Africa. While biomedical writings focus on HIV ‘origins’, we propose a broader look at the historical changes associated with the beginnings of the HIV/AIDS pandemic.
FREED SLAVES, MISSIONARIES, AND RESPECTABILITY: THE EXPANSION OF THE CHRISTIAN FRONTIER FROM ANGOLA TO BELGIAN CONGO
Authors: Maxwell David 
Published: May 2013

AbstractThis article extends the history of freed slaves from the well-studied areas of West Africa to the frontier between Angola and Belgian Congo. Originally enslaved by Ovimbundu traders in what became south-eastern Belgian Congo, these enslaved people became Christians through contact with Euro-American missions while labouring in Angola. Following the abolition of slavery in the Portuguese Empire in the 1910s, they returned to their home areas as Christian evangelists. In Belgian Congo, they helped to spread Christianity but clashed with missionaries over authority and respectability. Some struggled with the trauma of enslavement while others sought alternative routes to status and authority through participating in Independent Christian movements or assuming positions of traditional leadership.
HISTORICAL EPIDEMIOLOGY AND INFECTIOUS DISEASE PROCESSES IN AFRICA
Authors: Webb James L. A. 
Published: May 2013

AbstractThis article outlines the historical development in African studies of the sub-discipline of historical epidemiology and the contemporary challenges of understanding infectious disease processes that require integrating biomedical and historical knowledge. It suggests that Africanist historians can play a significant role in collaborative and multidisciplinary research in this field by exploring the histories of disease processes and interventions, and thereby contributing to improvements in public health practice and outcomes.
AFRO-CHRISTIAN SYNCRETISM IN THE KINGDOM OF KONGO
Authors: THORNTON JOHN K. 
Published: May 2013

AbstractThis article examines the way in which Christianity and Kongo religion merged to produce a syncretic result. After showing that the Kongo church grew up under the supervision and direction of Kongo authorities rather than missionaries, it will track how local educational systems and linguistic transformations accommodated the differences between the two religious traditions. In Kongo, many activities associated with the traditional religion were attacked as witchcraft without assigning any part of the traditional religion to this category. It also addresses how Kongo religious thinkers sidestepped questions of the fate of the dead and the virginity of Mary when harmonizing them would be too difficult.
Effect of non-extensivity during the collision between inward and outward ion acoustic solitary waves in cylindrical and spherical geometry
Authors: GHOSH UDAY NARAYAN , CHATTERJEE PRASANTA 
Published: May 2013

AbstractThe head-on collision between two cylindrical/spherical ion acoustic solitary waves (IASWs) in un-magnetized plasmas comprising inertial ions and q-non-extensive electrons and positrons is investigated using the extended version of the Poincaré–Lighthill–Kuo perturbation method. How the interactions are taking place in cylindrical and spherical geometry are studied, and the collision is shown at different times. The non-planar geometry can modify analytical phase shifts following the head-on collision are derived. The effects of q-non-extensive electrons and positrons on the phase shift are studied. It is shown that the properties of the interaction of IASWs in cylindrical and spherical geometry are very different.
Beyond ritual and economics: Maasai lion hunting and conservation politics
Authors: Goldman Mara J. , de Pinho Joana Roque , Perry Jennifer 
Published: May 2013

AbstractPopulations of the African lionPanthera leoare declining dramatically, with the species’ survival in some areas closely linked to levels of tolerance by rural communities. In Tanzania and Kenya several of the remaining lion populations outside protected areas reside adjacent to rural communities, where they are hunted. As many of these communities are Maasai, research and conservation efforts have focused on understanding and curbing Maasai lion hunting practices. Much of this work has been informed by a dichotomous explanatory model of Maasai lion hunting as either a ‘cultural’ ritual or a ‘retaliatory’ behaviour against predation on livestock. We present qualitative data from interviews (n = 246) in both countries to illustrate that lion hunting by Maasai is related to overlapping motivations that are simultaneously social, emotional and political (in response to conservation initiatives). Additional case study material from Tanzania highlights how politics associated with conservation activities and age-set dynamics affect lion hunting in complex and overlapping ways. Our findings contribute an ethnographic perspective on Maasai lion hunting, people–predator relations, and how these relations are linked to conservation politics.
Population dynamics of Ascaridia galli following single infection in young chickens
Authors: FERDUSHY TANIA , LUNA-OLIVARES LUZ ADILIA , NEJSUM PETER , ROEPSTORFF ALLAN KNUD , THAMSBORG STIG MILAN , KYVSGAARD NIELS CHRISTIAN 
Published: May 2013

SUMMARYThe population dynamics of Ascaridia galli was studied in 70 ISA Brown layer pullets, 42 of them were each experimentally infected with 500 embryonated A. galli eggs and 28 chickens were kept as uninfected controls. Six chickens from the infected group and 4 from the control group were necropsied at 3, 7, 10, 14, 21, 28 and 42 days post-infection (d.p.i.). The mean worm recovery varied from 11–20% of the infection dose with the highest recovery at 3 d.p.i. and the lowest at 21 and 42 d.p.i. (P < 0·05). More larvae were recovered from the intestinal wall than from the content (P < 0·0001) and intestinal content larvae were longer than those from the wall (mean length 1·6 and 1 mm, respectively, P < 0·0001). Although larvae were growing over time, a population of small-sized larvae (length < 1 mm) was recovered at all d.p.i. During the first week of infection most of the larvae were located in the anterior half of the jejunoileum but they moved posteriorly with the age of infection. Thus, a subpopulation of larvae mainly in the lumen grew with time while another subpopulation remained small and associated with the mucosa. During the infection both subpopulations moved to a more posterior localization in the gastrointestinal (GI) tract.
Father absence and depressive symptoms in adolescence: findings from a UK cohort
Authors: Culpin I. , Heron J. , Araya R. , Melotti R. , Joinson C. 
Published: May 2013

BackgroundPrevious studies suggest a link between parental separation or divorce and risk of depression in adolescence. There are, however, few studies that have prospectively examined the effects of timing of biological father absence on risk for depressive symptoms in adolescence while controlling for a range of confounding factors.MethodWe examine the association between father absence occurring in early (the first 5 years) and middle childhood (5–10 years) and adolescent depressive symptoms in a sample comprising 5631 children from the UK-based Avon Longitudinal Study of Parents and Children (ALSPAC). Self-reported depressive symptoms at 14 years were assessed using the Short Mood and Feelings Questionnaire (SMFQ). Father absence was assessed from maternal questionnaires completed at regular intervals from the birth of the study child up to 10 years.ResultsThere was evidence for an association between father absence in early childhood and increased odds of depressive symptoms at 14 years. This association was stronger in girls than in boys and remained after adjusting for a range of socio-economic, maternal and familial confounders assessed prior to the father's departure. Conversely, there was no evidence for an association between father absence in middle childhood and depressive symptoms at 14 years.ConclusionsFather absence in early childhood increases risk for adolescent depressive symptoms, particularly in girls. Future research should be aimed at identifying possible biological and psychosocial mechanisms linking father absence to depressive symptomatology to enable the development of family-based early prevention and intervention programmes targeting young children at risk.
Competing ideologies of linguistic authority amongst new speakers in contemporary Galicia
Authors: O'Rourke Bernadette , Ramallo Fernando 
Published: May 2013

AbstractWhile in many indigenous minority-language situations traditional native speaker communities are in decline, new speakers are emerging in the context of revitalization policies. Such policies, however, can have unforeseen consequences and lead to tensions between newcomers and existing speakers over questions of ownership, legitimacy, and authenticity. This article examines these tensions in the case of Galician in northwestern Spain, where “new speakers” have emerged in the context of revitalization policies since the 1980s. The subsequent spread of the language outside traditional Galician strongholds and into what were predominantly Spanish spaces complicates the traditional ideology about sociolinguistic authenticity and ownership and raises questions about who are the legitimate speakers of Galician, who has authority, and the potential tensions that such questions generate. To illustrate the tensions and paradoxes thatnewandnativespeakers face in this postrevitalization context, we draw on three discussion groups consisting of sixteen young Galicians. (New speakers, authority, authenticity, minority languages, Galician)*
Can quantum probability provide a new direction for cognitive modeling?
Authors: Pothos Emmanuel M. , Busemeyer Jerome R. 
Published: May 2013

AbstractClassical (Bayesian) probability (CP) theory has led to an influential research tradition for modeling cognitive processes. Cognitive scientists have been trained to work with CP principles for so long that it is hard even to imagine alternative ways to formalize probabilities. However, in physics, quantum probability (QP) theory has been the dominant probabilistic approach for nearly 100 years. Could QP theory provide us with any advantages in cognitive modeling as well? Note first that both CP and QP theory share the fundamental assumption that it is possible to model cognition on the basis of formal, probabilistic principles. But why consider a QP approach? The answers are that (1) there are many well-established empirical findings (e.g., from the influential Tversky, Kahneman research tradition) that are hard to reconcile with CP principles; and (2) these same findings have natural and straightforward explanations with quantum principles. In QP theory, probabilistic assessment is often strongly context- and order-dependent, individual states can be superposition states (that are impossible to associate with specific values), and composite systems can be entangled (they cannot be decomposed into their subsystems). All these characteristics appear perplexing from a classical perspective. However, our thesis is that they provide a more accurate and powerful account of certain cognitive processes. We first introduce QP theory and illustrate its application with psychological examples. We then review empirical findings that motivate the use of quantum theory in cognitive theory, but also discuss ways in which QP and CP theories converge. Finally, we consider the implications of a QP theory approach to cognition for human rationality.
Uncertainty about the value of quantum probability for cognitive modeling
Authors: Behme Christina 
Published: May 2013

AbstractI argue that the overly simplistic scenarios discussed by Pothos & Busemeyer (P&B) establish at best that quantum probability theory (QPT) is a logical possibility allowing distinct predictions from classical probability theory (CPT). The article fails, however, to provide convincing evidence for the proposal that QPT offers unique insights regarding cognition and the nature of human rationality.
Cold and hot cognition: Quantum probability theory and realistic psychological modeling
Authors: Corr Philip J. 
Published: May 2013

AbstractTypically, human decision making is emotionally “hot” and does not conform to “cold” classical probability (CP) theory. As quantum probability (QP) theory emphasises order, context, superimposition states, and nonlinear dynamic effects, one of its major strengths may be its power to unify formal modeling and realistic psychological theory (e.g., information uncertainty, anxiety, and indecision, as seen in the Prisoner's Dilemma).
On the quantum principles of cognitive learning
Authors: de Castro Alexandre 
Published: May 2013

AbstractPothos & Busemeyer's (P&B's) query about whether quantum probability can provide a foundation for the cognitive modeling embodies so many underlying implications that the subject is far from exhausted. In this brief commentary, however, I suggest that the conceptual thresholds of the meaningful learning give rise to a typical Boltzmann's weighting measure, which indicates astatistical verisimilitudeof quantum behavior in the human cognitive ensemble.
Does quantum uncertainty have a place in everyday applied statistics?
Authors: Gelman Andrew , Betancourt Michael 
Published: May 2013

AbstractWe are sympathetic to the general ideas presented in the article by Pothos & Busemeyer (P&B): Heisenberg's uncertainty principle seems naturally relevant in the social and behavioral sciences, in which measurements can affect the people being studied. We propose that the best approach for developing quantum probability models in the social and behavioral sciences is not by directly using the complex probability-amplitude formulation proposed in the article, but rather, more generally, to consider marginal probabilities that need not be averages over conditionals.
Cognitive architectures combine formal and heuristic approaches
Authors: Gonzalez Cleotilde , Lebiere Christian 
Published: May 2013

AbstractQuantum probability (QP) theory provides an alternative account of empirical phenomena in decision making that classical probability (CP) theory cannot explain. Cognitive architectures combine probabilistic mechanisms with symbolic knowledge-based representations (e.g., heuristics) to address effects that motivate QP. They provide simple and natural explanations of these phenomena based on general cognitive processes such as memory retrieval, similarity-based partial matching, and associative learning.
What are the mechanics of quantum cognition?
Authors: Navarro Daniel Joseph , Fuss Ian 
Published: May 2013

AbstractPothos & Busemeyer (P&B) argue that quantum probability (QP) provides a descriptive model of behavior and can also provide a rational analysis of a task. We discuss QP models using Marr's levels of analysis, arguing that they make most sense as algorithmic level theories. We also highlight the importance of having clear interpretations for basic mechanisms such as interference.
A quantum of truth? Querying the alternative benchmark for human cognition
Authors: Newell Ben R. , van Ravenzwaaij Don , Donkin Chris 
Published: May 2013

AbstractWe focus on two issues: (1) an unusual, counterintuitive prediction that quantum probability (QP) theory appears to make regarding multiple sequential judgments, and (2) the extent to which QP is an appropriate and comprehensive benchmark for assessing judgment. These issues highlight how QP theory can fall prey to the same problems of arbitrariness that Pothos & Busemeyer (P&B) discuss as plaguing other models.
Quantum modeling of common sense
Authors: Noori Hamid R. , Spanagel Rainer 
Published: May 2013

AbstractQuantum theory is a powerful framework for probabilistic modeling of cognition. Strong empirical evidence suggests the context- and order-dependent representation of human judgment and decision-making processes, which falls beyond the scope of classical Bayesian probability theories. However, considering behavior as the output of underlying neurobiological processes, a fundamental question remains unanswered: Is cognition a probabilistic process at all?
What's the predicted outcome? Explanatory and predictive properties of the quantum probability framework
Authors: Pleskac Timothy J. , Kvam Peter D. , Yu Shuli 
Published: May 2013

AbstractQuantum probability (QP) provides a new perspective for cognitive science. However, one must be clear about the outcome the QP model is predicting. We discuss this concern in reference to modeling the subjective probabilities given by people as opposed to modeling the choice proportions of people. These two models would appear to have different cognitive assumptions.
If quantum probability = classical probability + bounded cognition; is this good, bad, or unnecessary?
Authors: Rakow Tim 
Published: May 2013

AbstractQuantum probability models may supersede existing probabilistic models because they account for behaviour inconsistent with classical probability theory that are attributable to normal limitations of cognition. This intriguing position, however, may overstate weaknesses in classical probability theory by underestimating the role of current knowledge states and may under-employ available knowledge about the limitations of cognitive processes. In addition, flexibility in model specification has risks for the use of quantum probability.