pinecone/core-2020-05-10-deduplication huggingface dataset:
Revisiting non-relativistic limits

We show that the full spurionic symmetry of Galilean-invariant field theories can be deduced when those theories are the limits of relativistic parents. Under the limit, the non-relativistic daughter couples to Newton-Cartan geometry together with all of the symmetries advocated in previous work, including the recently revived Milne boosts. Our limit is a covariant version of the usual one, where we start with a gapped relativistic theory with a conserved charge, turn on a chemical potential equal to the rest mass of the lightest charged state, and then zoom in to the low energy sector. This procedure gives a simple physical interpretation for the Milne boosts. Our methods even apply when there is a magnetic moment, which is known to modify the non-relativistic symmetry transformations. We focus on two examples. Free scalars are used to demonstrate the basic procedure, whereas hydrodynamics is used in order to exhibit the power of this approach in a fully dynamical setting, correcting several inaccuracies in the existing literature
When do acquirers invest in the R&D assets of acquired science-based firms in cross-border acquisitions? The role of technology and capabilities similarity and complementarity

Drawing on a multiple case study of acquisitions of UK biopharmaceutical firms, we develop an analytical framework that elucidates how key determinants of the knowledge base of science-based firms and their combinations through M&As interact and affect post-acquisition investment in the target’s R&D projects. We show that two factors - the complementarity/ similarity of the technology, and the complementarity/ similarity of the discovery and development capabilities of the target and acquiring firm - interact to produce different outcomes in terms of investment in the acquired firm’s R&D assets and for the local science and technology system
Resistance of a sub-arctic bird community to severe forest damage caused by geometrid moth outbreaks

Outbreaks by geometrid moths periodically cause mass mortality of trees and state changes in understorey vegetation in sub-arctic mountain birch forest in northern Scandinavia. In order to assess the short-term impacts of such disturbance on forest bird communities, we
took bird censuses in forest where almost all birch trees had been killed by moth outbreaks 2–4 years before the study and in undamaged forest. The study was repeated in two locations (Kirkenes and Tana) with contrasting forest structure and fragmentation. Using a hierarchical community
model, we show that the total abundance of birds in Kirkenes was only about 25 % lower in damaged than undamaged forest and that species richness differed even less between the two forest types. Meanwhile, neither bird abundance nor species richness differed between damaged
and undamaged forest in Tana. The observed patterns in abundance were mainly driven by a few very common species. Only a single species showed indication of being more abundant in damaged forest. Thus, our findings indicate that bird communities in sub-arctic mountain birch forest have a high degree of resistance to forest damage caused by moth outbreaks. We suggest that bird
populations in outbreak-affected forest may be maintained by surviving trees and by standing dead tree trunks, which help maintain the vertical structure of the forest habitat. The fact that many of the studied bird species are habitat generalists may also explain their apparently weak responses
to the damage caused by the outbreak. Our results do not point towards forest damage caused by moth outbreaks as a major driver of change in bird communities in the study system, although more long-term research is needed to substantiate this conclusion
Formation of superheavy elements in the capture of very heavy ions at high excitation energies

The potential barriers governing the reactions 58Fe+244Pu, 238U+64Ni, and 238U+72Ge have been determined from a liquid-drop model taking into account the proximity energy, shell energies, rotational energy, and deformation of the incoming nuclei in the quasimolecular shape valley. Double-humped potential barriers appear in these entrance channels. The external saddle-point corresponds to two touching ellipsoidal nuclei when the shell and pairing effects are taken into account, while the inner barrier is due to the shell effects at the vicinity of the spherical shape of the composite system. Between them, a large potential pocket exists and persists at very high angular momenta allowing the capture of very heavy ions at high excitation energies
Reconstructing the Green's function through iteration of correlations.

International audienceCorrelations of ambient seismic noise are now widely used to retrieve the Earth response between two points. In this study, we reconstruct the surface-wave Green's function by iterating the correlation process over the tail of the noise-based correlation function. It has been demonstrated that the so-called C 3 function shows the surface-wave part of the Green's function. Using data from 150 continuously recording stations in Europe, the C 3 results help in the extraction of the travel-times from noise-based measurements, especially through the suppression of effects caused by non-isotropic source distributions. We present the results of the next iterative step (i.e. C 5), which show that some coherent signal is still present in the coda of the C 3 function, and we investigate the evolution of the reconstruction of the Green's function throughout the iteration process. Finally, we discuss the interest of combining information from the different correlation functions to improve noise-based tomography analysis
Elastic properties and surface damage resistance of nitrogen-rich (Ca,Sr)-Si-O-N glasses

International audienceCa and Sr-based oxynitride glasses with very high nitrogen content have been synthesized using metal hydrides as primary precursors. Values of Young's modulus, shear modulus, bulk modulus and Poisson's ratio were determined by means of ultrasonic echography. Vickers micro-indentation has been used to characterize hardness and indentation fracture toughness behaviour. Elastic moduli were found to increase linearly with nitrogen content, with the highest value of Young's modulus at 135 GPa, for a Ca-glass with 58 e/o of nitrogen. The Sr-glasses exhibit lower elastic moduli than Ca glasses. Poisson's ratio, hardness, indentation fracture toughness, crack initiation load and surface damage resistance were found to increase with increasing nitrogen content for both glass series. (C) 2010 Elsevier B.V. All rights reserved
PDB4DNA: Implementation of DNA geometry from the Protein Data Bank (PDB) description for Geant4-DNA Monte-Carlo simulations

International audienceThis paper describes PDB4DNA, a new Geant4 user application, based on an independent, cross-platform, free and open source C++ library, so-called PDBlib, which enables use of atomic level description of DNA molecule in Geant4 Monte Carlo particle transport simulations. For the evaluation 15 of direct damage induced on the DNA molecule by ionizing particles, the application makes use of an algorithm able to determine the closest atom in the DNA molecule to energy depositions. Both the PDB4DNA application and the PDBlib library are available as free and open sourc
GERMLINE GAIN-OF-FUNCTION MUTATIONS of ALK DISRUPT CENTRAL NERVOUS SYSTEM DEVELOPMENT

International audienceNeuroblastoma (NB) is a frequent embryonal tumour of sympathetic ganglia and adrenals with extremely variable outcome. Recently, somatic amplification and gain-of-function mutations of the anaplastic lymphoma receptor tyrosine kinase (ALK, MIM 105590) gene, either somatic or germline, were identified in a significant proportion of NB cases. Here we report a novel syndromic presentation associating congenital NB with severe encephalopathy and abnormal shape of the brainstem on brain MRI in two unrelated sporadic cases harbouring de novo, germline, heterozygous ALK gene mutations. Both mutations are gain-of-function mutations that have been reported in NB and NB cell lines. These observations further illustrate the role of oncogenes in both tumour predisposition and normal development, and shed light on the pleiotropic and activity-dependent role of ALK in humans. More generally, missing germline mutations relative to the spectrum of somatic mutations reported for a given oncogene may be a reflection of severe effects during embryonic development, and may prompt mutation screening in patients with extreme phenotypes
Small moving rigid body into a viscous incompressible fluid

International audienceWe consider a single disk moving under the influence of a 2D viscous fluid and we study the asymptotic as the size of the solid tends to zero.If the density of the solid is independent of $\varepsilon$, the energy equality is not sufficient to obtain a uniform estimate for the solid velocity. This will be achieved thanks to the optimal $L^p-L^q$ decay estimates of the semigroup associated to the fluid-rigid body system and to a fixed point argument. Next, we will deduce the convergence to the solution of the Navier-Stokes equations in $\mathbb{R}^2$
Self potential signals preceding variations of fumarole activity at Merapi volcano, Central Java.

International audienceThis paper analyzes simultaneous self-potential and gas temperature variations recorded at Merapi volcano in spring 2001, the dry season shortly after the volcanic crisis 2001. Temporal variations of fumarole gas temperature show characteristic quasi periodic signals at scales 1-8 hours and amplitudes up to ten degrees. We propose a simple graphical technique combining a wavelet scalogram and a cross-correlation analysis to demonstrate that the variations of gas temperature are systematically preceded by self-potential variations at the same scales. The influence of meteorological variations on these correlated signals can be ruled out. Rather, we suggest them to be related to the magma degassing in the upper conduits of the volcano. We discuss a semi-qualitative model to explain this correlation and the observed phase shift of about two hours
Acetylacetone stimulus effect on electrorheological properties of TiO2 aggregated nanoparticles.

International audienceWe present experimental results on electrorheological behavior under an ac electric field, and dielectric properties of colloidal suspensions composed of aggregated titanium dioxide nanoparticles dispersed in insulating PDMS silicon oil, as a function of adsorbed acetylacetone (Acac) dipolar molecules on TiO2 surface. The results show that the elastic modulus G′ of TiO2-Acac/PDMS ER fluid decreases when the electric field frequency is increased gradually from 10 to 104 Hz. In the range of tested electric field frequencies, we observe that the dielectric properties are given essentially by an interfacial polarization which is maximal at low frequency. At low frequency (υ = 10 Hz), G′ increases with the increasing Acac/TiO2 surface coverage θ from 0 to 0.45, due to the high polarization of the particles caused by the increase of the charge carriers that move to the interface between TiO2 particles and the insulating medium. For θ = 0.35, G′ reaches 1.80 MPa which is 3.6 times greater than that of pure TiO2/PDMS ER fluid. However, G′ decreases by increasing θ beyond 0.45; in such cases, the mismatch on dielectric constant and conductivity between dispersed phase (TiO2) and insulating medium (PDMS) begins to fall as θ increases because of the increase of Acac dipoles remaining free in PDMS. The performance of TiO2-Acac/PDMS ER fluid at low frequency was validated by a reversibility test where elastic modulus G′ increases dramatically and returns to its initial state as soon as several cycles of a switching electric field were applied between 0 and 1 kV/mm successively
Preliminary results of a paleoseismological analysis along the Sahel fault (Algeria): New evidence for historical seismic events

International audienceThe ∼60 km-long Sahel ridge west of Algiers (Tell Atlas, north Algeria) is considered as an ENE-WSW fault-propagation fold running along the Mediterranean coast and associated with a north-west dipping thrust. Its proximity with Algiers makes this structure a potential source of destructive earthquakes that could hit the capital city, as occurred in 1365 AD and 1716 AD. The first paleoseismologic investigation on the Sahel ridge was conducted in order to detect paleo-ruptures related to active faulting and to date them. From the first investigations in the area, a first trench was excavated across bending-moment normal faults induced by flexural slip folding in the hanging wall of the Sahel anticline thrust ramp. Paleoseismological analyses recognize eight rupture events affecting colluvial deposits. 14C dating indicates that these events are very young, six of them being younger than 778 AD. The first sedimentary record indicates two ruptures before 1211 AD, i.e. older than the first historical earthquake documented in the region. Three events have age ranges compatible with the 1365, 1673 and 1716 Algiers earthquakes, whereas three other ones depict very recent ages, i.e. younger than 1700 AD. Potential of these secondary extrados faults for determining paleoseismic events and thrust behaviour is discussed
Evidences for the Key Role of Hydrogen Bonds in Nucleophilic Aromatic Substitution Reactions

International audienceThe effect of hydrogen bonds on the fate of nucleophilic aromatic substitutions (SNAr) has been studied in silico using a density functional theory approach in the condensed phase. The importance of these hydrogen bonds can explain the “built-in solvation” model of Bunnett concerning intermolecular processes between halogenonitrobenzenes and amines. It is also demonstrated that it can explain experimental results for a multicomponent reaction (the Ugi–Smiles coupling), involving an intramolecular SNAr (the Smiles rearrangement) as the key step of the process. Modeling reveals that when an intramolecular hydrogen bond is present, it lowers the activation barrier of this step and enables the multicomponent reaction to proceed
Allocative efficiency and traders' protection under zero intelligence behavior

This paper studies the continuous double auction from the point of view of market engineering: we tweak a resampling rule often used for this exchange protocol and search for an improved design. We assume zero intelligence trading as a lower bound for more robust behavioral rules and look at allocative efficiency,
as well as three subordinate performance criteria: mean spread, cancellation rate, and traders’ protection. This latter notion measures the ability of a protocol to help traders capture their share of the competitive equilibrium profits.
We consider two families of resampling rules and obtain the following results. Full resampling is not necessary to attain high allocative efficiency, but fine-tuning the resampling rate is important. The best allocative performances are similar across
the two families. However, if the market designer adds any of the other three criteria as a subordinate goal, then a resampling rule based on a price band around the best quotes is superior
The impact of the great recession on employment polarization in Spain

This article analyzes changes in the occupational employment share in Spain for the period 1997 - 2012 and the way particular sociodemographic groups adapt to those changes. There seems to be clear evidence of employment polarization between 1997 and 2012 that accelerates over the recession. Changes in the composition of the labour supply cannot explain the increase in the share of occupations at the low end of the wage distribution. Sector reallocation may have partially contributed to explain the polarization process in Spain during the years of expansion (1997 - 2007) but it is a minor factor during the recession. The polarization of occupations within sectors observed, especially during the recession, appears to be related to a decline in routine tasks which is compensated by an increase in occupations with non-routine service contents, which are found both in the low and high end of the wage distribution. Instead, jobs with a higher degree of abstract contents do not appear to increase their share in total employment during these 15 years. The paper finds that this process has affected males more strongly than females because of their higher concentration in occupations more focused on routine tasks. Among males, for workers under 30 years old, we find a decrease in the share of occupations with more routine tasks which turns into increases in those with more abstract content and particularly with more non-routine service content. Instead, male workers over 30 years old seem to remain in declining occupations to a greater extent. Females of different ages are not affected by the abovementioned changes
Determination of thermal wave reflection coefficient to better estimate defect depth using pulsed thermography

Thermography is a promising method for detecting subsurface defects, but accurate measurement of defect depth is still a big challenge because thermographic signals are typically corrupted by imaging noise and affected by 3D heat conduction. Existing methods based on numerical models are susceptible to signal noise and methods based on analytical models require rigorous assumptions that usually cannot be satisfied in practical applications. This paper presents a new method to improve the measurement accuracy of subsurface defect depth through determining the thermal wave reflection coefficient directly from observed data that is usually assumed to be pre-known. This target is achieved through introducing a new heat transfer model that includes multiple physical parameters to better describe the observed thermal behaviour in pulsed thermographic inspection. Numerical simulations are used to evaluate the performance of the proposed method against four selected state-of-the-art methods. Results show that the accuracy of depth measurement has been improved up to 10% when noise level is high and thermal wave reflection coefficients is low. The feasibility of the proposed method in real data is also validated through a case study on characterising flat-bottom holes in carbon fibre reinforced polymer (CFRP) laminates which has a wide application in various sectors of industry
Simulation benchmarks for low-pressure plasmas: capacitive\ud
discharges

Benchmarking is generally accepted as an important element in demonstrating the correctness of computer simulations. In the modern sense, a benchmark is a computer simulation result that has evidence of correctness, is accompanied by estimates of relevant errors, and which can thus be used as a basis for judging the accuracy and efficiency of other codes. In this paper, we present four benchmark cases related to capacitively coupled discharges. These benchmarks prescribe all relevant physical and numerical parameters. We have simulated the benchmark conditions using five independently developed particle-in-cell codes. We show that the results of these simulations are statistically indistinguishable, within bounds of uncertainty that we define. We therefore claim that the results of these simulations represent strong benchmarks, that can be used as a basis for evaluating the accuracy of other codes. These other codes could include other approaches than particle-in-cell simulations, where benchmarking could examine not just implementation accuracy and efficiency, but also the fidelity of different physical models, such as moment or hybrid models. We discuss an example of this kind in an appendix. Of course, the methodology that we have developed can also be readily extended to a suite of benchmarks with coverage of a wider range of physical and chemical phenomena
Soil water availability modulation over estimated relative yield losses in wheat (Triticum aestivum L.) due to ozone exposure

The approach developed by Fuhrer in 1995 to estimate wheat yield losses induced by ozone and modulated by the soil water content (SWC) was applied to the data on Catalonian wheat yields. The aim of our work was to apply this approach and adjust it to Mediterranean environmental conditions by means of the necessary corrections. The main objective pursued was to prove the importance of soil water availability in the estimation of relative wheat yield losses as a factor that modifies the effects of tropospheric ozone on wheat, and to develop the algorithms required for the estimation of relative yield losses, adapted to the Mediterranean environmental conditions. The results show that this is an easy way to estimate relative yield losses just using meteorological data, without using ozone fluxes, which are much more difficult to calculate. Soil water availability is very important as a modulating factor of the effects of ozone on wheat; when soil water availability decreases, almost twice the amount of accumulated exposure to ozone is required to induce the same percentage of yield loss as in years when soil water availability is high
Thermal transfer simulation regarding the rotational moulding of polyamide 11

Simulation of thermal phenomena in rotational moulding is very important to follow the evolution of the temperature in various zones of this process. It was a question of modelling heat gradients developing in rota-tional moulding part. Thermal model tested take into account the temperature change (thermal transfer mecha-nism) of melting and crystallization pseudo-stages (enthalpy method). Series of tests in polyamide 11 (PA11) were carried out by means of rotational moulding STP LAB, and non-isothermal crystallization kinetics of rota-tional moulding PA11 grade are measured and analysed by DSC technique type TAQ20. A result of non-isothermal crystallization of the studied polyamide was confronted with Ozawa model. In order to test the validity degree of enthalpy method (layer to layer), another approach based on Ozawa model has also been used in the case of cooling pseudo-stage. As results, the rotational moulding of PA11 was successfully carried out. The simulation of the fusion and crystallization stages, by application of Ozawa model coupled with enthalpy method gave a good representation of experimental data
Safety assessment of underground vehicles passing over highly resilient curved tracks in the presence of a broken rail

Vehicle–track interaction for a new resilient slab track designed to reduce noise and vibration levels was analysed, in order to assess the derailment risk on a curved track when encountering a broken rail. Sensitivity of the rail support spacing of the relative position of the rail breakage between two adjacent rail supports and of running speed were analysed for two different elasticities of the rail fastening system.\ud
\ud
In none of the cases analysed was observed an appreciable difference between either of the elastic systems. As was expected, the most unfavourable situations were those with greater rail support spacing and those with greater distance from the breakage to the nearest rail support, although in none of the simulations performed did a derailment occur when running over the broken rail. When varying the running speed, the most favourable condition was obtained for an intermediate speed, due to the superposition of two antagonistic effects
Fracture behaviour of notched round bars made of PMMA subjected to torsion at -60 °C

This paper presents seventy new experimental results from PMMA notched specimens\ud
tested under torsion at 60 C. The notch root radius ranges from 0.025 to 7.0 mm. At this\ud
temperature the non-linear effects previously observed on specimens of the same material\ud
tested at room temperature strongly reduce.\ud
The averaged value of the strain energy density over a control volume is used to assess\ud
the critical loads to failure. The radius of the control volume and the critical strain energy\ud
density are evaluated a priori by using in combination the mode III critical stress intensity\ud
factor from cracked-like specimens and the critical stress to failure detected from semicircular\ud
notches with a large notch root radiu