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The dynamics and control of a vortex pair in ground effect are investigated in a planar, incompressible and laminar setting. The evolution of the vortices obtained numerically shows vortex rebound as a consequence of the separation of the boundary layer induced at the wall by the vortices. An optimal control approach is developed and employed for vortex Reynolds numbers of 200 and 1000 in order to identify the optimal Dirichlet boundary condition at the wall to counteract this rebound and allow for an increased lateral displacement of the vortex, similarly to the inviscid evolution of the flow, which features hyperbolic trajectories. The work is primarily a conceptual approach to deal with aircraft separation distances in airport airspace by moving the vortices laterally, away from the runway but may also apply to the control of coherent structures in wall bounded turbulence. The most efficient control is able to double the lateral position and yields mostly vertical in and outflow at the wall. An optimal horizon time is found, equal to 5 characteristic time units of the vortex system, beyond which control is not able to further displace the vortices. The control is shown to delay the separation of the boundary layer at the origin of vortex rebound by applying suction ahead of the vortex, and to generate a vorticity flux at the wall, leading to a pusher vortex of sign opposite to that of the primary vortex, that attenuates the effect of the no-slip boundary condition at the wall by pushing the vortex outward.
Situations of internecine warfare have in common to question the transitivity of everyday life—that is, its capacity to be taken for granted, to flow without any need for explication. These wars within the familiar generate specific anxieties about where to look at and what to believe. Events, persons, places, or objects whose status seemed hitherto undeniable become less predictable, while their worth comes into question. As individuals’ ontological security is threatened, the need for new monitoring devices and authentication procedures arises. Drawing on the phenomenology of civil wars and the anthropology of fakes, this contribution proposes to explore one such crisis of evidence: the nexus of political, ethnic, and criminal violence raging in Karachi's inner-city area of Lyari. Through the lens of local journalism, it reflects upon the tactics of social navigation deployed by residents confronted with chronic uncertainty in all sectors of life. Janbaz, the Urdu newspaper examined here, provides an opportunity to move beyond functionalist readings of the press in conflict situations. While insisting upon the pleasure derived by Janbaz’s readers from the sensationalized rendering of Lyari's predicament, we argue that the newspaper is the site of a continuous series of ‘reality tests’ and the focal point of private and collective investigations, pooling knowledge in an increasingly undecipherable environment. More than through its information, it is through its shortcomings that Janbaz has helped to recreate social ties in a world plagued by discord and uncertainty.
Mountain building in the Al-Hajar Mountains (NE Oman) occurred during two major shortening stages, related to the convergence between Africa–Arabia and Eurasia, separated by nearly 30 Ma of tectonic quiescence. Most of the shortening was accommodated during the Late Cretaceous, when northward subduction of the Neo-Tethys Ocean was followed by the ophiolites obduction on top of the former Mesozoic margin. This shortening event lasted until the latest Santonian – early Campanian. Maastrichtian to Eocene carbonates unconformably overlie the eroded nappes and seal the Cretaceous foredeep. These neo-autochthonous post-nappe sedimentary rocks were deformed, along with the underlying Cretaceous tectonic pile, during the second shortening event, itself including two main exhumation stages. In this study we combine remotely sensed structural data, seismic interpretation, field-based structural investigations and apatite (U–Th)/He (AHe) cooling ages to obtain new insights into the Cenozoic deformation stage. Seismic interpretation indicates the occurrence of a late Eocene flexural basin, later deformed by an Oligocene thrusting event, during which the post-nappe succession and the underlying Cretaceous nappes of the internal foredeep were uplifted. This stage was followed by folding of the post-nappe succession during the Miocene. AHe data from detrital siliciclastic deposits in the frontal area of the mountain chain provide cooling ages spanning from 17.3 to 42 Ma, consistent with available data for the structural culminations of Oman. Our work points out how renewal of flexural subsidence in the foredeep and uplift of the mountain belt were coeval processes, followed by layer-parallel shortening preceding final fold amplification.
After acquiring 91 km2 of lidar data from the Zacapu region, West Mexico, we confronted a series of issues that most archaeologists using this technology face. These include the large volume of data available, the limited training of potential “analysts,” the difficult development of a collective mapping tool and protocol, and the reliability of desk-based interpretation of archaeological features. In this article, we present an initiative conducted in 2015 and 2017 as an attempt to answer these methodological and pedagogical issues. We developed a web mapping platform to collectively interpret archaeological features using lidar-derived imagery and to train volunteer students to participate in this desk-based web mapping within a crowdsourcing framework. After evaluating the results of this initiative, we discuss the potential and limitations of this method for both lidar-based research and future training.
Although there is a plethora of cancer associated-factors that can ultimately culminate in death (cachexia, organ impairment, metastases, opportunistic infections, etc.), the focal element of every terminal malignancy is the failure of our natural defences to control unlimited cell proliferation. The reasons why our defences apparently lack efficiency is a complex question, potentially indicating that, under Darwinian terms, solutions other than preventing cancer progression are also important contributors. In analogy with host-parasite systems, we propose to call this latter option ‘tolerance’ to cancer. Here, we argue that the ubiquity of oncogenic processes among metazoans is at least partially attributable to both the limitations of resistance mechanisms and to the evolution of tolerance to cancer. Deciphering the ecological contexts of alternative responses to the cancer burden is not a semantic question, but rather a focal point in understanding the evolutionary ecology of host-tumour relationships, the evolution of our defences, as well as why and when certain cancers are likely to be detrimental for survival.
Starchy diets can induce hindgut dysbiosis in horses. The present study evaluated the impact of a yeast (Saccharomyces cerevisiae) and microalgae (Aurantiochytrium limacinum) supplementation on caecal, colonic and faecal microbial ecosystem and on blood inflammatory parameters of horses fed high-fibre or high-starch diets. Six fistulated geldings in a 2 × 2 Latin-square design were alternatively supplemented and received during each period 100 % hay (4 weeks) followed by a 56/44 hay/barley diet (3 weeks). Caecal, colonic and faecal samples were collected 4 h after the morning meal three times per diet, at 5-d intervals, to measure bacterial composition and microbial end products. Blood was simultaneously collected for measuring inflammatory markers. The starchy diet clearly modified the microbial ecosystem in the three digestive segments, with an increase of the amylolytic function and a decrease of the fibrolytic one. However, no effect of the diet was observed on the blood parameters. When horses were supplemented, no significant change was found in lipopolysaccharides, PG-E2, serum amyloid A concentrations and complete blood count neither in cellulose-utilising, starch-utilising and lactate-utilising bacteria concentrations nor in the volatile fatty acids and lactate concentrations and pH. Under supplementation, relative abundance of Family XIII Clostridiales increased in caecum and faeces irrespective of diet and relative abundance of Veillonellaceae was higher during the hay/barley diet in colon and faeces. Most variations of faecal bacterial taxa under supplementation were not observed in the hindgut. However, all variations suggested that supplementation could increase fibrolytic function whatever the diet and limit dysbiosis when the horses’ diet changed from high fibre to high starch.
This article explains why autocrats love constitutional pluralism and constitutional identity. Though these concepts were developed by scholars and jurists with the best of intentions in mind, we explain why they are also attractive to and inherently prone to abuse by autocrats. We then describe how the regimes in Hungary and Poland have made use of these concepts in their drive to consolidate autocracy. We conclude that given the dangers inherent in constitutional pluralism and its susceptibility to abuse, it should be replaced with a more traditional understanding of the primacy of EU law.
The coherence and systemic strength of the collaborative process among thematic route stakeholders are key factors to economic success for individual businesses and regional economic development. The objective of this article is to identify the economic action set to rejuvenate the Cider Route and the Wine Route of the Montérégie region (Quebec, Canada). Group concept mapping is used to estimate the conceptualization and perceptions of stakeholders (cideries, wineries, tourism professionals, visitors) regarding the articulation of the action set. The contribution is threefold. Methodologically, the approach taken supports both the estimation of the concept map and associated perception measures. Empirically, eight action clusters are identified to articulate stakeholders’ “organizational” and “selling” dimensions of the routes. Practically, action priorities identified and feasibility constraints are helpful to target the capability development support needed by route stakeholders to collaborate. (JEL Classifications: D02, L23, L26, L66, Q18)
This paper investigates the large-scale flow reorientations of Rayleigh–Bénard convection in a cubic cell using proper orthogonal decomposition (POD) analysis and modelling. A direct numerical simulation is performed for air at a Rayleigh number of
and shows that the flow is characterized by four quasi-stable states, corresponding to a large-scale circulation lying in one of the two diagonal planes of the cube with a clockwise or anticlockwise motion, with occasional brief reorientations. Proper orthogonal decomposition is applied to the joint velocity and temperature fields of an enriched database which captures the statistical symmetries of the flow. We found that each quasi-stable state consists of a superposition of four spatial modes representing three types of structures: (i) a mean-flow mode consisting of two stacked counter-rotating torus-like structures; (ii) two large-scale two-dimensional rolls (pair of degenerated modes) which form large-scale diagonal rolls when combined together; and (iii) an eight-roll mode that transports fluid from one corner to the other and strengthens the circulation along the diagonal. In addition, we identified three other modes that play a role in the reorientation process: two boundary-layer modes (pair of degenerated modes) that connect the core region with the horizontal boundary layers and one mode associated with corner rolls. The symmetries of the different POD modes are discussed, as well as their temporal dynamics. A description of the reorientation process in terms of POD modes is provided and compared with other modal approaches available in the literature. Finally, Galerkin projection is used to derive a POD-based reduced-order model. Unresolved modes are accounted for in the model by an extra dissipation term and the addition of noise. A seven-mode model is able to reproduce the low-frequency dynamics of the large-scale reorientations as well as the high-frequency dynamics associated with the large-scale circulation rotation. Linear stability analysis and sensitivity analysis confirm the role of the boundary-layer modes and the corner-rolls mode in the reorientation process.
Western Europe is often used as the basis from which to understand the Aurignacian of other regions. For some there is good inter-regional chronocultural agreement, whereas others see significant difference. One region frequently argued to differ is the Swabian Jura (southern Germany). In a recent contribution to this issue Bataille and Conard (2018) describe the Aurignacian assemblage from Layer IV of Hohle Fels. They convincingly outline important similarities with the Western European Late Aurignacian. However, they also argue that it is older than, and different from, the most comparable Western European assemblages, and therefore that it contradicts an Aurignacian chronocultural framework built on Western European evidence. Here we assess this claim, focusing on the sites used by Bataille and Conard in their comparison. Radiocarbon dates for Hohle Fels IV of 33–30,000 uncal bp are no older than dates for Western European Late Aurignacian assemblages. Most of the features of Hohle Fels IV argued to demonstrate its dissimilarity are, in fact, evident in the Western European Late Aurignacian. One potential difference is the reported absence from Hohle Fels IV of microblades with inverse/alternate retouch. However, due to the near absence of laterally retouched microblades and uncertainty over whether the fine fraction has been searched we doubt the significance of this observation. Other recent publications have similarly suggested that the Western European chronocultural model is incompatible with other regions. In light of this we consider Eastern Europe. Despite some difference, reliable data point to the pene-contemporaneity of characteristic bladelet/microblade technologies between the two regions, a pattern that stratigraphies from sites across Europe are also consistent with. The biggest complicating factor is radiocarbon dating, which has created a culturally complex picture that is inconsistent with all chronostratigraphic data. We therefore offer some thoughts as to the use of radiocarbon dates for this period. Despite ongoing problems dates are still frequently presented with an unwarranted confidence in their accuracy. Their presentation should instead explicitly acknowledge the method’s fallibility and its inferiority to more reliable evidence such as chronostratigraphic patterning and tephra. When radiocarbon dates contradict a consistent chronostratigraphic picture the burden of proof falls to those arguing the dates’ veracity. In these cases, the reasons for the discrepancy between the radiocarbon and chronostratigraphic records require exploration.
The poultry red mite (PRM) is an obligatory haematophagous pest that causes substantial economic losses in poultry worldwide. The PRM does not live on the host but in the bird's environment and must find its host remotely. Hence, manipulating chicken odours is of interest. Several crude plant-originating volatile organic compounds (VOCs) have already been shown as repellent to Dermanyssus gallinae. We aimed to test whether these VOCs can interfere with PRM host-seeking behaviour by their oral administration to the poultry. The objectives were to determine (1) if hen odours are modified by supplemented feed ingestion and (2) if such treatment makes hens less attractive to the PRM. Chemical characterization by gas chromatography–mass spectrometry of the hen odour was conducted before and after the hens ingested the supplemented feed. The chromatograms obtained show that hen odour was substantially modified after the hens consumed it. Among the molecules recurrently detected from the supplemented hens, 26% were nearly absent in the unsupplemented hens. Behavioural choice tests to compare the effect of the modified and unmodified-host odours on the PRM show that some of the plant-originating emitted VOCs and the modified whole-hen odours were repellent to the PRM.
Urban-type rough-wall boundary layers developing over staggered cube arrays with plan area packing density,
, of 6.25 %, 25 % or 44.4 % have been studied at two Reynolds numbers within a wind tunnel using hot-wire anemometry (HWA). A fixed HWA probe is used to capture the outer-layer flow while a second moving probe is used to capture the inner-layer flow at 13 wall-normal positions between
is the height of the roughness elements. The synchronized two-point HWA measurements are used to extract the near-canopy large-scale signal using spectral linear stochastic estimation and a predictive model is calibrated in each of the six measurement configurations. Analysis of the predictive model coefficients demonstrates that the canopy geometry has a significant influence on both the superposition and amplitude modulation. The universal signal, the signal that exists in the absence of any large-scale influence, is also modified as a result of local canopy geometry suggesting that although the nonlinear interactions within urban-type rough-wall boundary layers can be modelled using the predictive model as proposed by Mathis et al. (J. Fluid Mech., vol. 681, 2011, pp. 537–566), the model must be however calibrated for each type of canopy flow regime. The Reynolds number does not significantly affect any of the model coefficients, at least over the limited range of Reynolds numbers studied here. Finally, the predictive model is validated using a prediction of the near-canopy signal at a higher Reynolds number and a prediction using reference signals measured in different canopy geometries to run the model. Statistics up to the fourth order and spectra are accurately reproduced demonstrating the capability of the predictive model in an urban-type rough-wall boundary layer.
Most research on mortality in people with severe psychiatric disorders has focused on natural causes of death. Little is known about trauma-related mortality, although bipolar disorder and schizophrenia have been associated with increased risk of self-administered injury and road accidents.
To determine if 30-day in-patient mortality from traumatic injury was increased in people with bipolar disorder and schizophrenia compared with those without psychiatric disorders.
A French national 2016 database of 144 058 hospital admissions for trauma was explored. Patients with bipolar disorder and schizophrenia were selected and matched with mentally healthy controls in a 1:3 ratio according to age, gender, social deprivation and region of residence. We collected the following data: sociodemographic characteristics, comorbidities, trauma severity characteristics and trauma circumstances. Study outcome was 30-day in-patient mortality.
The study included 1059 people with bipolar disorder, 1575 people with schizophrenia and their respective controls (n = 3177 and n = 4725). The 30-day mortality was 5.7% in bipolar disorder, 5.1% in schizophrenia and 3.3 and 3.8% in the controls, respectively. Only bipolar disorder was associated with increased mortality in univariate analyses. This association remained significant after adjustment for sociodemographic characteristics and comorbidities but not after adjustment for trauma severity. Self-administered injuries were associated with increased mortality independent of the presence of a psychiatric diagnosis.
Patients with bipolar disorder are at higher risk of 30-day mortality, probably through increased trauma severity. A self-administered injury is predictive of a poor survival prognosis regardless of psychiatric diagnosis.
We collected dietary records over the course of nine months to comprehensively characterize the consumption patterns of Malagasy people living in remote rainforest areas of north-eastern Madagascar.
The present study was a prospective longitudinal cohort study to estimate dietary diversity and nutrient intake for a suite of macronutrients, micronutrients and vitamins for 152 randomly selected households in two communities.
Madagascar, with over 25 million people living in an area the size of France, faces a multitude of nutritional challenges. Micronutrient-poor staples, especially rice, roots and tubers, comprise nearly 80 % of the Malagasy diet by weight. The remaining dietary components (including wild foods and animal-source foods) are critical for nutrition. We focus our study in north-eastern Madagascar, characterized by access to rainforest, rice paddies and local agriculture.
We enrolled men, women and children of both sexes and all ages in a randomized sample of households in two communities.
Although the Household Dietary Diversity Score and Food Consumption Score reflect high dietary diversity, the Minimum Dietary Diversity–Women indicator suggests poor micronutrient adequacy. The food intake data confirm a mixed nutritional picture. We found that the median individual consumed less than 50 % of his/her age/sex-specific Estimated Average Requirement (EAR) for vitamins A, B12, D and E, and Ca, and less than 100 % of his/her EAR for energy, riboflavin, folate and Na.
Malnutrition in remote communities of north-eastern Madagascar is pervasive and multidimensional, indicating an urgent need for comprehensive public health and development interventions focused on providing nutritional security.
Many expressions in African societies identify groups that operate between the legal and illegal at the frontier of petty and serious crime: tsotsis or skollies in South Africa; wahuni in Tanzania; jaguda boys, boma boys or area boys in Nigeria. They designate broad categories that embrace the criminal, the delinquent, the young and the jobless. For a large section of society, these common labels represent the embodiment of danger, disorder, crime and delinquency. To consider an unemployed young person and a leader of a gang as belonging to the same category shows the difficulty in disentangling joblessness and crime, the need to investigate the permanently shifting frontier between legal and illegal labour and to recognize the difficulty in capturing what constitutes crime in various African countries.
Crime in the African continent has been shaped by different imperial and national legal histories. In English-speaking countries, the term ‘crime’ is often used to designate an offence committed by adults, as opposed to ‘delinquency’, which is associated most of the time with juvenile offenders. By contrast, in French-speaking countries, ‘crime’ is used to designate the most serious offences which require severe penalties. Instead of emphasizing these particular distinctions, I will use ‘crime’ as a behaviour or action prosecuted by the law that threatens the perpetrator with a penalty. This conventional definition is complicated by the fact that many African countries have inherited various legal histories of different origins (European and Islamic, as well as local traditions reshaped by colonial and national laws). Studying crime thus implies looking at incriminating processes, that is, the making of criminal codes, but also understanding what is locally perceived as crime in a continent in which the state's monopoly on law and order is far from obvious.
Illegal labour is a notion that is no less ambivalent. Legal definitions are scarce at the global level. For the Organisation for Economic Co-operation and Development (OECD), illegal work concerns persons who are not legally authorized to work. This may involve, for instance, work by children below the prescribed minimum age, migrant workers without work permits or government employees who hold a second job incompatible with the duties of their first job.