pinecone/core-2020-05-10-deduplication huggingface dataset:
On Higher-Dimensional Dynamics

Technical results are presented on motion in N(>4)D manifolds to clarify the physics of Kaluza-Klein theory, brane theory and string theory. The so-called canonical or warp metric in 5D effectively converts the manifold from a coordinate space to a momentum space, resulting in a new force (per unit mass) parallel to the 4D velocity. The form of this extra force is actually independent of the form of the metric, but for an unbound particle is tiny because it is set by the energy density of the vacuum or cosmological constant. It can be related to a small change in the rest mass of a particle, and can be evaluated in two convenient gauges relevant to gravitational and quantum systems. In the quantum gauge, the extra force leads to Heisenberg's relation between increments in the position and momenta. If the 4D action is quantized then so is the higher-dimensional part, implying that particle mass is quantized, though only at a level of 10^{-65} gm or less which is unobservably small. It is noted that massive particles which move on timeline paths in 4D can move on null paths in 5D. This agrees with the view from inflationary quantum field theory, that particles acquire mass dynamically in 4D but are intrinsically massless. A general prescription for dynamics is outlined, wherein particles move on null paths in an N(>4)D manifold which may be flat, but have masses set by an embedded 4D manifold which is curved
Prediction of microgeometrical influences on micropitting fatigue damage on 32CrMoV13 steel

Dr Fabre's sabbatical period at the Cardiff School of Engineering allowed the research to be conducted. Thanks are due to the M2P department of Arts et Métiers ParisTech, to Arts et Métiers ParisTech—Aix en Provence, and to the MécaSurf laboratory for supporting the visit financially, and to Cardiff University for provision of research facilities. Dr Sharif's contribution to the research was supported financially by UK Engineering & Physical Sciences Research Council (EPSRC) with Grant no. EP/G06024X/1.Micropitting is a form of surface fatigue damage that occurs in the gear teeth. It is  due to the effect of variation in the mechanical loading in the contact zone between the two teeth, induced especially by flank roughness. In this study, generic roughness profiles were built with geometrical parameters to simulate the contact between two rough surfaces. Using elastohydrodynamic lubrication code and Crossland’s fatigue criteria, the influence on fatigue lifetime was analysed for changes in each parameter. The relevant parameters were determined that influence(i) the conventional pitting,(ii) the extent to which the von Mises equivalent stress exceeds the material yield stress in the zone where micropitting occurs, and(iii) the fatigue lifetime for steel teeth. With nitriding benefits, the same trends were shown with weaker effects
Oxidation of unvulcanized, unstabilized polychloroprene: A kinetic study

Thermal oxidation in air at atmospheric pressure, in the 80-140 °C temperature range and in oxygen at 100 °C in the 0.02-3 MPa pressure range, of unvulcanized, unstabilized, unfilled polychloroprene (CR) has been characterized using FTIR and chlorine concentration measurement. The kinetic analysis was focused on double bond consumption. A mechanistic scheme involving unimolecular and bimolecular hydroperoxide decomposition, oxygen addition to alkyl radicals, hydrogen abstraction on allylic methylenes, alkyl and peroxyl additions to double bonds and terminations involving alkyl and peroxy radicals was elaborated. The corresponding rate constants were partly extracted from the literature and partly determined from experimental data using the kinetic model derived from the mechanistic scheme in an inverse approach. Among the specificities of polychloroprene, the following were revealed: The rate of double bond consumption is a hyperbolic function of oxygen pressure that allows a law previously established for the oxidation of saturated substrates to be generalized. CR oxidation is characterized by the absence of an induction period that reveals the instability of hydroperoxides. The kinetic analysis also reveals that peroxyl addition is faster than hydrogen abstraction but slower in CR than in common hydrocarbon polydienes
Regional centrality and tax competition for FDI

We examine a trade model where three countries compete for an exogenous number of firms. In our hub-and-spoke framework, one country is the hub through which all trade with and between spokes takes place. We establish the distribution of industrial activity in the absence of taxes and compare it to the equilibrium when countries compete to attract firms. Even when all countries are the same size, the centrality of the hub sets it apart. We determine how this trading pattern matters, comparing it to a structure with direct trade between all countries. The implications of international tax competition are also examined
Fluctuating sea-cage environments modify the effects of stocking densities on production and welfare parameters of Atlantic salmon (Salmo salar L.)

Stocking densities are commonly used to set limits for the production of fish in sea-cages, yet limited information exists to assess how environmental fluctuations modify the effects of stocking densities on the production and welfare of fish. Atlantic salmon (Salmo salar L.) of average size 1.3 kg were held at high (15.7–32.1 kg m−3) or normal (5.6–14.5 kg m−3) stocking densities in triplicate 2000 m3 sea-cages from August to December. Intense crowding within both the high (189 kg m− 3, 10 × stocking density) and normal (147 kg m− 3, 17 × stocking density) density cages occurred when sub-optimal temperatures limited the amount of vertical space available. In addition, when stocking density in the high treatment exceeded 26.5 kg m− 3, feed intake, growth rate and feed utilisation declined and a greater number of cataracts, fin erosions and skin lesions developed. Fish with cataracts on both eyes were smaller than fish with only one or no cataracts. High stocking densities have significant detrimental effects on production and welfare, particularly when they are exacerbated by environments that drive crowding. Stocking densities should therefore be based on the characteristics of each location, to account for the influence of environmental variability
Is Complexity a Scientific Concept?

Complexity science has proliferated across academic domains in recent years. A question arises as to whether any useful sense of ‘generalized complexity’ can be abstracted from the various versions of complexity to be found in the literature, and whether it could prove fruitful in a scientific sense. Most attempts at defining complexity center around two kinds of notions: Structural, and temporal or dynamic. Neither of these is able to provide a foundation for the intuitive or generalized notion when taken separately; structure is often a derivative notion, dependent on prior notions of complexity, and dynamic notions such as entropy are often indefinable. The philosophical notion of process may throw light on the tensions and contradictions within complexity. Robustness, for instance, a key quality of complexity, is quite naturally understood within a process-theoretical framework. Understanding complexity as process also helps one align complexity science with holistically oriented predecessors such as General System Theory, while allowing for the reductionist perspective of complexity. These results, however, have the further implication that it may be futile to search for general laws of complexity, or to hope that investigations of complex objects in one domain may throw light on complexity in unrelated domains
The Land-Potential Knowledge System (LandPKS): mobile apps and collaboration for optimizing climate change investments

Massive investments in climate change mitigation and adaptation are projected during coming decades. Many of these investments will seek to modify how land is managed. The return on both types of investments can be increased through an understanding of land potential: the potential of the land to support primary production and ecosystem services, and its resilience. A Land-Potential Knowledge System (LandPKS) is being developed and implemented to provide individual users with point-based estimates of land potential based on the integration of simple, geo-tagged user inputs with cloud-based information and knowledge. This system will rely on mobile phones for knowledge and information exchange, and use cloud computing to integrate, interpret, and access relevant knowledge and information, including local knowledge about land with similar potential. The system will initially provide management options based on long-term land potential, which depends on climate, topography, and relatively static soil properties, such as soil texture, depth, and mineralogy. Future modules will provide more specific management information based on the status of relatively dynamic soil properties such as organic matter and nutrient content, and of weather. The paper includes a discussion of how this system can be used to help distinguish between meteorological and edaphic drought
Superradiant instability of the Kerr brane

We consider linear gravitational perturbations of the Kerr brane, an exact solution of vacuum Einstein’s equations in dimensions higher than four and a low-energy solution of string theory. Decomposing the perturbations in tensor harmonics of the trans-verse Ricci-flat space, we show that tensor- and vector-type metric perturbations of the Kerr brane satisfy respectively a massive Klein-Gordon equation and a Proca equation on the four-dimensional Kerr space, where the mass term is proportional to the eigenvalue of the harmonics. Massive bosonic fields trigger a well-known superradiant instability on a Kerr black hole. We thus establish that Kerr branes in dimensions D ≥ 6 are gravi-tationally unstable due to superradiance. These solutions are also unstable against the Gregory-Laflamme instability and we discuss the conditions for either instability to occur and their rather different nature. When the transverse dimensions are compactified and much smaller than the Kerr horizon, only the superradiant instability is present, with a time scale much longer than the dynamical time scale. Our formalism can be also used to discuss other types of higher-dimensional black objects, taking advantage of recent progress in studying linear perturbations of four-dimensional black holes
Gauge theories with 16 supersymmetries on spheres

We give a unified approach to localization of maximally symmetric gauge theories on spheres, including S 6 and S 7 . The approach follows Pestun’s method of dimensionally reducing from 10 dimensional super Yang-Mills. The resulting theories have a reduced R -symmetry which includes an SU(1 , 1) subgroup, except in four dimensions where, because of conformal invariance, the full flat-space R -symmetry is maintained, and in seven dimensions where SU(1 , 1) is the flat-space R -symmetry. For the case of S 6 and S 7 we discuss the localization of these theories and also present new results for the corresponding matrix models. The matrix models for S 6 and S 7 are qualitatively similar to the matrix models of a vector multiplet on S 4 and S 5 respectively. We also discuss the contributions of instantons in the six and seven dimensional cases
Interpolating between a and F

We study the dimensional continuation of the sphere free energy in conformal field theories. In continuous dimension d we define the quantity F ˜ $$ \tilde{F} $$ =sin( πd/ 2) log Z , where Z is the path integral of the Euclidean CFT on the d -dimensional round sphere. F ˜ $$ \tilde{F} $$ smoothly interpolates between (−1) d /2 π/ 2 times the a -anomaly coefficient in even d , and (−1) ( d +1)/2 times the sphere free energy F in odd d . We calculate F ˜ $$ \tilde{F} $$ in various examples of unitary CFT that can be continued to non-integer dimensions, including free theories, double-trace deformations at large N , and perturbative fixed points in the ϵ expansion. For all these examples F ˜ $$ \tilde{F} $$ is positive, and it decreases under RG flow. Using perturbation theory in the coupling, we calculate F ˜ $$ \tilde{F} $$ in the Wilson-Fisher fixed point of the O ( N ) vector model in d = 4 − ϵ to order ϵ 4 . We use this result to estimate the value of F in the 3-dimensional Ising model, and find that it is only a few percent below F of the free conformally coupled scalar field. We use similar methods to estimate the F values for the U( N ) Gross-Neveu model in d = 3 and the O ( N ) model in d = 5. Finally, we carry out the dimensional continuation of interacting theories with 4 supercharges, for which we suggest that F ˜ $$ \tilde{F} $$ may be calculated exactly using an appropriate version of localization on S d . Our approach provides an interpolation between the a -maximization in d = 4 and the F -maximization in d = 3
2D sigma models and differential Poisson algebras

We construct a two-dimensional topological sigma model whose target space is endowed with a Poisson algebra for differential forms. The model consists of an equal number of bosonic and fermionic fields of worldsheet form degrees zero and one. The action is built using exterior products and derivatives, without any reference to a worldsheet metric, and is of the covariant Hamiltonian form. The equations of motion define a universally Cartan integrable system. In addition to gauge symmetries, the model has one rigid nilpotent supersymmetry corresponding to the target space de Rham operator. The rigid and local symmetries of the action, respectively, are equivalent to the Poisson bracket being compatible with the de Rham operator and obeying graded Jacobi identities. We propose that perturbative quantization of the model yields a covariantized differential star product algebra of Kontsevich type. We comment on the resemblance to the topological A model
Nonthermal plasma assisted photocatalytic oxidation of dilute benzene

Oxidative decomposition of low concentrations (50-1000 ppm) of diluted benzene in air was carried out in a nonthermal plasma (NTP) dielectric barrier discharge (DBD) reactor with the inner electrode made up of stainless steel fibres (SMF) modified with transition metal oxides in such a way to integrate the catalyst in discharge zone. Typical results indicate the better performance of MnOx and TiO2/MnOx modified systems, which may be attributed to the in situ decomposition of ozone on the surface of MnOx that may lead to the formation of atomic oxygen; whereas ultraviolet light induced photocatalytic oxidation may be taking place with TiO2 modified systems. Water vapour improved the selectivity to total oxidatio
Adducin-1 is essential for mitotic spindle assembly through its interaction with myosin-X

Mitotic spindles are microtubule-based structures, but increasing evidence indicates that filamentous actin (F-actin) and F-actin-based motors are components of these structures. ADD1 (adducin-1) is an actin-binding protein that has been shown to play important roles in the stabilization of the membrane cortical cytoskeleton and cell-cell adhesions. In this study, we show that ADD1 associates with mitotic spindles and is crucial for proper spindle assembly and mitotic progression. Phosphorylation of ADD1 at Ser12 and Ser355 by cyclin-dependent kinase 1 enables ADD1 to bind to myosin-X (Myo10) and therefore to associate with mitotic spindles. ADD1 depletion resulted in distorted, elongated, and multipolar spindles, accompanied by aberrant chromosomal alignment. Remarkably, the mitotic defects caused by ADD1 depletion were rescued by reexpression of ADD1 but not of an ADD1 mutant defective in Myo10 binding. Together, our findings unveil a novel function for ADD1 in mitotic spindle assembly through its interaction with Myo10
Disentangling goods, labor, and credit market frictions in three European economies

We build a flexible model with search frictions in three markets: credit, labor, and goods markets. We then apply this model (called CLG) to three different economies: a flexible, finance-driven economy (the UK), an economy with wage moderation (Germany), and an economy with structural rigidities (Spain). In these three countries, goods and credit market frictions play a dominant role in entry costs and account for 75% to 85% of the total entry costs. In the goods market, adverse supply shocks are amplified through their propagation to the demand side, as they also imply income losses for consumers. This adds up to, at most, an additional 15% to 25% to the impact of the shocks. Finally, the speed of matching in the goods market and the credit market accounts for a small fraction of unemployment: most variation in unemployment comes from the speed of matching in the labor market
Mechanical behaviour at high temperature of alkali-activated aluminosilicates (geopolymers)

This study was designed to determine the effect of temperature on the mechanical strength (in both in vivo and post-exposure trials) of two alkaline cements (without OPC): (a) 100% ﬂy ash (FA) and (b) 85% FA + 15% bauxite, the activated alkaline solution used was 85% 10-M NaOH + 15% sodium silicate. A Type I 42.5 R Portland cement was used as a control. Two series of trials were conducted: (i) in vivo trials in which bending and compressive strength, fracture toughness and modulus of elasticity were determined at different temperatures; and (ii) post-ﬁring trials, assessing residual bending and compres-sive strength after a 1-h exposure to high temperatures and subsequent cooling. The ﬁndings showed that from 25 to 600  C, irrespective of the type of test (in vivo or post-ﬁring), compressive mechanical strength rose, with the specimens exhibiting elastic behaviour and consequently brittle failure. At tem-peratures of over 600  C, behaviour differed depending on the type of test: (i) in the in vivo trials the high temperature induced pseudo-plastic strain and a decline in mechanical strength that did not necessarily entail specimen failure; (ii) in the post-ﬁring trials, compressive strength rose
Development of an engineering identity: Personal discovery of classroom mathematics in “real engineering”

This article reports on an activity in a first-year engineering mathematics class designed to strengthen students’ personal identities as novice engineers. The literature on identity suggests that students are more likely to be retained in an engineering degree programme if they develop an identity as an engineer and that development of such an identity is encouraged and supported if students can see the relevance of their studies to future studies or their future career. The mathematics encountered at a first-year level is often of an unrealistic nature due to its largely algebraic content as well as to the fact that real-world engineering problems are often intractable without using more advanced mathematics than is accessible in a first-year course. The activity described in this article endeavoured to build empirically on the theoretical issues raised in the literature by asking “Can students identify the presence of classroom mathematics in real-world engineering texts and does this recognition encourage the development of identity as a novice engineer?” Sixty-six students studying first-year engineering mathematics in an academic development programme at a South African university took part in the activity. Data consisted of the students’ written assignments and their responses to a Likert-style questionnaire. The written assignments were graded on the strength of their alignment with the task’s mathematical requirements. Specifically within the course topic of Applications of Differentiation, the students were required to use resources from the library and the internet to find examples in real-world engineering where differentiation is used for practical purposes. The examples that the students investigated were necessarily expressed in the discourse of engineering, yet drew on mathematics the students had recently encountered in the classroom. This evident trajectory of knowledge from pure classroom practice to real-world engineering use allowed the students ready access to the discourse of engineering and ideally fostered development of identity as an active novice participant in the world of real engineering. A minority of students did not succeed in the task requirements, but the bulk of the students found the task interesting and informative. Several students expressed surprise and pleasure that they were able to understand what they were reading, revealing to them that they were already participants in the engineering community with some fluency in the discourse
Accurate measurements of fission-fragment yields in $^{234,235,236,238}$U(γ,f) with the SOFIA set-up

Open Access article distributed under the terms of the Creative Common attribution Licence 4.0International audienceSOFIA (Studies On Fission with Aladin) is a new experimental setup dedicated to accurate measurement of fission-fragments isotopic yields. It is located at GSI, the only place to use inverse kinematics at relativistic energies in order to study the (γ,f) electromagnetic-induced fission. The SOFIA setup is a large-acceptance magnetic spectrometer, which allows to fully identify both fission fragments in coincidence on the whole fission-fragment range. This paper will report on fission yields obtained in 234,235,236,238 U(γ,f) reactions
Surface site density, silicic acid retention and transport properties of compacted magnetite powder

International audienceIn France, within the framework of investigations of the feasibility of deep geological disposal of high-level radioactive waste, studies on corrosion products of steel over packs are ongoing. Such studies concern silica and radionuclide retention. The objective of the present work is to study sorption of silicic acid on compacted magnetite in percolation cells to attempt to simulate confined site conditions. Potentiometric titration of commercial magnetite was carried out with both dispersed and compacted magnetite. The titration of the magnetite suspension has been made with two different methods: a batch method (several suspensions) and a direct fast method (one suspension). The Gran's function gave 1.7 (±0.4) and 2.4 (±0.5) sorption sites nm−2 with these respective methods but site densities as high as 20/nm2 could be obtained by modelling. The titration of magnetite compacted at 120 bars showed that the evolution of charge density on magnetite surfaces is similar for compacted and dispersed magnetite. Silicic acid sorption onto dispersed and compacted magnetite was similar with sorption site densities ranging between 2.2 and 4.4/nm2
Radiation effects on ALICE V0 detector components

International audienceThe 60 MeV proton beam delivered by the RADEF facility of the University of Jyväskylä (Finland) was used to measure the radiation effects on the counter components of the V0 detector of ALICE. There are the scintillator BC404, the wavelength shifting fibres BCF9929A and the optical fibres BCF98 from Bicron (Saint-Gobain). The light yield and the time resolution given by a counter of the inner ring of the V0C array, mounted within a dedicated device, were measured as a function of the radiation dose up to about 300 krad. A global light attenuation of the order of 30% can be anticipated during 10 years of ALICE running