pinecone/core-2020-05-10-deduplication huggingface dataset:
Plant β-diversity i in human-altered forest ecosystems: the importance of the structural, spatial, and topographical characteristics of stands in patterning plant species assemblages

An understanding of spatial patterns of plant species diversity and the factors that drive those patterns is critical for the development of appropriate biodiversity management in forest ecosystems. We studied the spatial organization of plants species in human- modified and managed oak forests (primarily, Quercus faginea) in the Central Pre- Pyrenees, Spain. To test whether plant community assemblages varied non-randomly across the spatial scales, we used multiplicative diversity partitioning based on a nested hierarchical design of three increasingly coarser spatial scales (transect, stand, region). To quantify the importance of the structural, spatial, and topographical characteristics of stands in patterning plant species assemblages and identify the determinants of plant diversity patterns, we used canonical ordination. We observed a high contribution of ˟-diversity to total -diversity and found ˟-diversity to be higher and ˞-diversity to be lower than expected by random distributions of individuals at different spatial scales. Results, however, partly depended on the weighting of rare and abundant species. Variables expressing the historical management intensities of the stand such as mean stand age, the abundance of the dominant tree species (Q. faginea), age structure of the stand, and stand size were the main factors that explained the compositional variation in plant communities. The results indicate that (1) the structural, spatial, and topographical characteristics of the forest stands have the greatest effect on diversity patterns, (2) forests in landscapes that have different land use histories are environmentally heterogeneous and, therefore, can experience high levels of compositional differentiation, even at local scales (e.g., within the same stand). Maintaining habitat heterogeneity at multiple spatial scales should be considered in the development of management plans for enhancing plant diversity and related functions in human-altered forest
Optoelectronic property analysis of MCrO4 (M=Ba, Sr) with a response to visible light irradiation

Ternary MCrO4 (M = Ba, Sr) semiconductors are materials with a variety of photocatalyst and optoelectronic applications. We present detailed microscopic analyses based on first principles of the structure, the electronic properties and the optical absorption in which the difference between symmetrically non-equivalent atoms has been considered. The high absorption coefficients of these materials are split into chemical species contributions in accordance with the symmetry. The high optical absorption in these materials is mainly because of the Cr–O inter-species transitions
Adaptation strategies for high order discontinuous Galerkin methods based on Tau-estimation

In this paper three p-adaptation strategies based on the minimization of the truncation error are presented for high order discontinuous Galerkin methods. The truncation error is approximated by means of a ? -estimation procedure and enables the identification of mesh regions that require adaptation. Three adaptation strategies are developed and termed a posteriori, quasi-a priori and quasi-a priori corrected. All strategies require fine solutions, which are obtained by enriching the polynomial order, but while the former needs time converged solutions, the last two rely on non-converged solutions, which lead to faster computations. In addition, the high order method permits the spatial decoupling for the estimated errors and enables anisotropic p-adaptation. These strategies are verified and compared in terms of accuracy and computational cost for the Euler and the compressible Navier?Stokes equations. It is shown that the two quasi- a priori methods achieve a significant reduction in computational cost when compared to a uniform polynomial enrichment. Namely, for a viscous boundary layer flow, we obtain a speedup of 6.6 and 7.6 for the quasi-a priori and quasi-a priori corrected approaches, respectively
Methodological Realism and Modal Resourcefulness: Out of the Web and Into the Mine

Psillos (1999, 2011), Kitcher (1993), and Leplin (1997) have defended convergent scientific realism against the pessimistic meta-induction by arguing for the divide et impera (DEI) strategy. I argue that DEI faces a problem more serious than the pessimistic meta-induction: the problem of accretion. When empirically successful theories and principles are combined, they may no longer make successful predictions or allow for accurate calculations, or the combination otherwise may be an empirical failure. The shift from classical mechanics to the new quantum theory does not reflect the discarding of “idle wheels.” Instead, scientists had to contend with new principles that made classical calculations difficult or impossible (the Maxwell-Boltzmann equipartition theorem), and new results (the anomalous Zeeman effect) that were inconsistent with classical theorems (the Larmor theorem), and that suggested a new way of conceiving of atomic dynamics. In this shift, reference to atoms and to electrons was preserved, but the underlying causal explanations and descriptions of atoms and electrons changed. I propose that the emphasis on accurate description of causal agents as a virtue of background theory be replaced with Ruetsche’s (2011) advocacy of pragmatic, modal resourcefulness
An Exploratory Analysis of Long-Term Trends in Atmospheric CO2 Concentrations

A new methodological approach for analysis of monitoring data is discussed. The main ideas are illustrated for the example of the CO2 problem. The analysis of CO2 concentrations obtained from a global network of monitoring stations permitted the authors to construct a  nonparametric evaluation of the spatial-temporal distribution of this field. They propose a parabolic parametrization of the long-term tendency of this field as a function of time (in one-year time steps). A function of the predicitve ability of a model is defined on the basis of the technique of "supervised training". This function is computed for a parabolic model and it is shown that this model constructed for the first 15 years of observations evaluates the tendency for the next 15 years quite well. The main problem that is solved in this paper is how to correlate the projections of different models for the carbon cycle and different scenarios of the annual release of carbon into the atmosphere with the projection that reflect parametrization of the trends of CO2-monitoring data
Inhomogeneity of donor doping in SrTiO3 substrates studied by fluorescence-lifetime imaging microscopy

Fluorescence-lifetime imaging microscopy (FLIM) was applied to investigate the donor distribution in SrTiO3 single crystals. On the surfaces of Nb- and La-doped SrTiO3, structures with different fluorescence intensities and lifetimes were found that could be related to different concentrations of Ti3+. Furthermore, the inhomogeneous distribution of donors caused a non-uniform conductivity of the surface, which complicates the production of potential electronic devices by the deposition of oxide thin films on top of doped single crystals. Hence, we propose FLIM as a convenient technique (length scale: 1 μm) for characterizing the quality of doped oxide surfaces, which could help to identify appropriate substrate materials
Proof of the fundamental BCJ relations for QCD amplitudes

The fundamental BCJ-relation is a linear relation between primitive tree amplitudes with different cyclic orderings. The cyclic orderings differ by the insertion place of one gluon. The coefficients of the fundamental BCJ-relation are linear in the Lorentz invariants 2 p i p j . The BCJ-relations are well established for pure gluonic amplitudes as well as for amplitudes in N = 4 $$ \mathcal{N}=4 $$ super-Yang-Mills theory. Recently, it has been conjectured that the BCJ-relations hold also for QCD amplitudes. In this paper we give a proof of this conjecture. The proof is valid for massless and massive quarks
Constraints on the quantum state of pairs produced by semiclassical black holes

The pair-production process for a black hole (BH) is discussed within the framework of a recently proposed semiclassical model of BH evaporation. Our emphasis is on how the requirements of unitary evolution and strong subadditivity act to constrain the state of the produced pairs and their entanglement with the already emitted BH radiation. We find that the state of the produced pairs is indeed strongly constrained but that the semiclassical model is consistent with all requirements. We are led to the following picture: Initially, the pairs are produced in a state of nearly maximal entanglement amongst the partners, with a parametrically small entanglement between each positive-energy partner and the outgoing radiation, similar to Hawking’s model. But, as the BH evaporation progresses past the Page time, each positive-energy partner has a stronger entanglement with the outgoing radiation and, consequently, is less strongly entangled with its negative-energy partner. We present some evidence that this pattern of entanglement does not require non-local interactions, only EPR-like non-local correlations
Pure connection formalism for gravity: recursion relations

In the gauge-theoretic formulation of gravity the cubic vertex becomes simple enough for some graviton scattering amplitudes to be computed using the Berends-Giele-type recursion relations. We present such a computation for the current with all same helicity on-shell gravitons. Once the recursion relation is set up and low graviton number cases are worked out, a natural guess for the solution in terms of a sum over trees readily presents itself. The solution can also be described either in terms of the half-soft function familiar from the 1998 paper by Bern, Dixon, Perelstein and Rozowsky or as a matrix determinant similar to one used by Hodges for MHV graviton amplitudes. This solution also immediately suggests the correct guess for the MHV graviton amplitude formula, as is contained in the already mentioned 1998 paper. We also obtain the recursion relation for the off-shell current with all but one same helicity gravitons
New formulation of the type IIB superstring action in AdS 5 × S 5

Previous studies of the type IIB superstring in an AdS 5 × S 5 background are based on a description of the superspace geometry as the quotient space PSU(2 , 2|4) / SO(4 , 1) × SO(5). This paper develops an alternative approach in which the Grassmann coordinates provide a nonlinear realization of PSU(2 , 2|4) based on the quotient space PSU(2 , 2|4) / SU(2 , 2) × SU(4), and the bosonic coordinates are described as a submanifold of SU(2 , 2) × SU(4). This formulation keeps all bosonic symmetries manifest, and it provides the complete dependence on the Grassmann coordinates in terms of simple analytic expressions. It is used to construct the superstring world-sheet action in a form in which the PSU(2 , 2|4) symmetry is manifest and kappa symmetry can be established. This formulation might have some advantages compared to previous ones, but this remains to be demonstrated
Dilaton, screening of the cosmological constant and IR-driven inflation

It is known that infrared (IR) quantum fluctuations in de Sitter space could break the de Sitter symmetry and generate time dependent observable effects. In this paper, we consider a dilaton-gravity theory. We find that gravitational IR effects lead to a time dependent shift on the vev of the dilaton and results in a screening (temporal) of the cosmological constant/Hubble parameter. In the Einstein frame, the effect is exponentiated and can give rises to a much more notable amount of screening. Taking the dilaton as inflaton, we obtain an inflationary expansion of the slow roll kind. This inflation is driven by the IR quantum effects of de Sitter gravity and does not rely on the use of a slow roll potential. As a result, our model is free from the eta problem which baffle the standard slow roll inflation models
Attosecond-correlated dynamics of two electrons in argon

In this work we explored strong field-induced decay of doubly excited transient Coulomb complex Ar** → Ar2++ 2e. We measured the correlated two-electron emission as a function of carrier envelop phase (CEP) of 6 fs pulses in the non-sequential double ionization (NSDI) of argon. Classical model calculations suggest that the intermediate doubly excited Coulomb complex loses memory of its formation dynamics. We estimated the ionization time difference between the two electrons from NSDI of argon and it is 200 ± 100 as (N Camus et al, Phys. Rev. Lett. 108, 073003 (2012
Coupled Electromagnetic–Structural Simulation of Magnetic Pulse Welding

The present study deals with the coupled magnetic–structural analysis of magnetic pulse welding (MPW) process applied on a tubular workpiece. The study investigates the various criteria required for a successful weld between the mating members through a finite element model. The transient electromagnetic field phenomenon is coupled sequentially with mechanical phenomenon. The coupling between the magnetic field and the electrical circuit is formulated in the electromagnetic part of the model, whereas in the structural part, the impact velocities, the effective plastic strain and the shear stress induced in the workpiece are found from the numerical simulations. A viscoplastic material model with rate-dependent material properties is considered in the structural part. The effect of varying process parameters: input voltage and air gap between the two mating members on weld quality are computed through numerical simulations. Based on the results of the numerical simulations, an optimal weldability window is suggested
A Second Best Theory of Institutional Quality

This paper illustrates a theory of the second best where the constraints to the achievement of the optimum are of institutional nature. We consider the effects of corruption and bad governance on the public decision to privatize the provision of a service when contracts are incomplete and there is asymmetric information. We show that both corruption and bad governance are detrimental to welfare, but that removing only one of the two is not necessarily beneficial if the other is still present. The theory supplies a possible explanation to the controversial empirical evidence on the economic effects of corruption
Palaeo-ice stream pathways and retreat style in the easternmost Amundsen Sea Embayment, West Antarctica, revealed by combined multibeam bathymetric and seismic data

Multibeam swath bathymetry data sets collected over the past two decades have been compiled to identify palaeo-ice stream pathways in the easternmost Amundsen Sea Embayment. We mapped ~ 3000 glacial landforms to reconstruct ice flow in the ~ 250-km-long cross-shelf Abbot Trough. This bathymetric feature was occupied by a large ice stream, which was fed by two tributaries (Cosgrove and Abbot) and reached the continental shelf edge during the last maximum ice sheet advance. Geomorphological mapping has enabled a clear differentiation between subglacial landforms indicating warm- (e.g., megascale glacial lineations) and cold-based (e.g., hill–hole pairs) ice conditions on the continental shelf during the last glaciation. Grounding-zone wedges and recessional moraines, mapped within the palaeo-ice stream troughs and on adjacent sea-floor highs (referred to as inter-ice stream ridges) indicate grounding line stillstands or re-advances of the West Antarctic Ice Sheet during the last deglaciation of the shelf. We observe that the locations of grounding-zone wedges coincide with trough constrictions as well as local topographic highs of harder substrate. This combination of trough ‘bottlenecks’ and local pinning points on an otherwise retrograde slope is likely to have modified the pace of grounding-line retreat, causing the grounding zone to pause and deposit grounding-zone wedges. The episodic retreat recorded within Abbot Trough corresponds to post-glacial episodic retreat interpreted for the neighbouring Pine Island–Thwaites palaeo-ice stream trough, thus suggesting a uniform pattern of retreat across the eastern Amundsen Sea Embayment. Locally, indications are strong that a change in basal thermal regime of the ice from warm- to cold-based conditions occurred prior to final retreat, as hill–hole pairs overprint megascale glacial lineations. Further, the correlation of grounding-zone wedges with geological boundaries emphasises the influence of subglacial geology on ice stream flow. Our new geomorphological map of the easternmost Amundsen Sea Embayment resolves the pathways of palaeo-ice streams that were probably all active during the last maximum extent of the ice sheet, and the extent of adjacent inter-ice stream ridges. It reveals information about the style of, and the basal thermal regime during, the subsequent grounding line retreat. Such information provides an important empirical framework by which the accuracy of ice sheet models can be gauged
A real-time Active Routing approach via a database for airport surface movement

Airports face challenges due to the increasing volume of air traffic and tighter environmental restrictions which result in a need to actively integrate speed profiles into conventional routing and scheduling procedure. However, only until very recently, the research on airport ground movement has started to take into account such a speed profile optimisation problem actively so that not only time efficiency but also fuel saving and decrease in airport emissions can be achieved at the same time. It is envisioned that the realism of planning could also be improved through speed profiles. However, due to the multi-objective nature of the problem and complexity of the investigated models (objective functions), the existing speed profile optimisation approach features high computational demand and is not suitable for an on-line application. In order to make this approach more competitive for real-world application and to meet limits imposed by International Civil Aviation Organization for on-line decision time, this paper introduces a pre-computed database acting as a middleware to effectively separate the planning (routing and scheduling) module and the speed profile generation module. Employing a database not only circumvents duplicative optimisation for the same taxiway segments, but also completely avoids the computation of speed profiles during the on-line decision support owing a great deal to newly proposed database initialization procedures. Moreover, the added layer of database facilitates, in the future, more complex and realistic models to be considered in the speed profile generation module, without sacrificing on-line decision time. The experimental results carried out using data from a major European hub show that the proposed approach is promising in speeding up the search process
Breakup reaction study of the Brunnian nucleus $^{10}$C

The structure and 2α + 2p breakup of $^{10}$C, the only known Brunnian nucleus, has been studied at 33.3 MeV/nucleon. The breakup kinematics were used to reconstruct the $^{10}$C→$^{9}$B +p, $^{9}$B→$^{8}$Be +p, $^{8}$Be→ α + α and $^{10}$C → $^{6}$Be +α, $^{6}$Be → $^{5}$Li +p, $^{5}$Li → α + p decay paths. Proton emission was seen to be favored. The decay of excited states at Ex = 4.20, 5.31, and 6.74 MeV was observed. The previously unobserved state at 4.20 MeV may correspond to a J$^{π}$ = 0$^{+}$α + 2p + α cluster structure
Synthesis and characterization of thorium-bearing britholites

RADIOCHIn the field of the immobilization of tri- and tetravalent minor actinides, apatites and especially britholites were already proposed as good candidates. In order to simulate tetravalent minor actinides, the incorporation of thorium, through dry chemical routes, was studied in britholite samples of general formula Ca9Nd1−xThx(PO4)5−x(SiO4)1+xF2. The study showed that the incorporation of thorium was effective whatever the thorium reagent used or the grinding conditions considered. Nevertheless, it appeared necessary to use mechanical grinding (30 Hz, 15 min) before heating treatment (T = 1400 °C, 6 h) to improve the reactivity of powders and the sample homogeneity. In these conditions, the incorporation of thorium in the britholite structure occurred above 1100 °C. The heating treatment at 1400 °C led to single phase and homogeneous compounds. This work also underlined the necessity to prefer the coupled substitution Click to view the MathML source instead of (Nd3+, F−) left right double arrow (Th4+, O2−) in order to prepare pure and single phase samples in all the range of composition examined
Information Systems and Assemblages

International audienceThe theme for the 2014 IFIP WG 8.2 working conference was ‘Information Systems and Global Assemblages: (Re)Configuring Actors, Artefacts, Organizations’. The motivation behind the choice of the conference theme has been the increasing appreciation of notions of emergence, heterogeneity and temporality in IS studies. We found that the conference provided an opportune occasion for inviting scholars interested in exploring these notions, their relevance and promise for IS studies. The concept of the ‘assemblage’ [1], already referenced in IS studies, as will be discussed below, and with significant popularity in other fields, such as anthropology, geography and cultural studies, provided the stepping stone for approaching the heterogeneous, emergent and situated nature of information systems and organization. In particular, we opted for highlighting the ‘global assemblage’[2] as a metaphor to talk about challenging yet often creative tensions that emerge as global imperatives (geographical, intellectual, procedural and others) interact with local arrangements of actors, artefacts and organizations. Here ‘global’ does not mean universal or everywhere, but mobile, abstractable, and capable of recontextualization across diverse social and cultural situations.This book provides a collection of contributions by scholars who responded to our invitation, adding depth and breadth to our understanding of the concept and its value for IS studies. At the same time, some contributors chose to discuss emergence, heterogeneity and situatedness in different terms, drawing upon alternative theoretical traditions and concepts. The result has been an engaging and stimulating mix of ideas that points towards the ‘multiple’ trajectories - current and future - of this exciting stream of research
Designing techniques for systemic impact: lessons from C-K theory and matroid structures

International audienceAs underlined in Arthur " s book " the nature of technology " we are very knowledgeable on the design of objects, services or technical systems, but we don " t know much on the dynamics of technologies. Still contemporary innovation often consists in designing techniques with systemic impact. They are pervasive– both invasive and perturbing-, they recompose the family of techniques. Can we model the impact and the design of such techniques? More specifically: how can one design generic technology, ie a single technology that provokes a complete reordering of families of techniques? Recent advances in design theories open new possibilities to answer these questions. In this paper we use C-K design theory and a matroid-based model of the set of techniques to propose a new model (C-K/Ma) of the dynamics of techniques, accounting for the design of generic technologies. We show:  F1: C-K/Ma offers a computational model for designing a technique with systemic impact. This model sheds new light on the logics of combination in design – the model helps to identify four logics of " combinations " , from non-generative combinatorics to generative one