pinecone/core-2020-05-10-deduplication huggingface dataset:
Does special relativity theory tell us anything new about space and
  time?

It will be shown that, in comparison with the pre-relativistic
Galileo-invariant conceptions, special relativity tells us nothing new about
the geometry of spacetime. It simply calls something else "spacetime", and this
something else has different properties. All statements of special relativity
about those features of reality that correspond to the original meaning of the
terms "space" and "time" are identical with the corresponding traditional
pre-relativistic statements. It will be also argued that special relativity and
Lorentz theory are completely identical in both senses, as theories about
spacetime and as theories about the behavior of moving physical objects.Comment: 26 pages, LaTeX, new passages adde
A One-Motor Full-Mobility 6-PUS Manipulator

8 páginas, 2 figuras.-- Trabajo presentado al 18th CISM-IFToMM Symposium on Robot Design, Dynamics and Control (ROMANSY) celebrado en Udine (Italia) del 5 al 8 de Julio de 2010.This paper presents the feasibility study of an under-actuated parallel manipulator with 6-PUS topology, destined to handle work-tables in\ud
CNC machine tools. The proposed device exploits the fact that, in such an application, the path between the initial and final poses of the mobile platform is not assigned to reduce the number of actuators to only one.This work was supported by the Spanish Ministry of Science and Innovation, by the contribution of Regione Emilia Romagna (District Councillorship for Productive Assets, Economic Development, Telematic Plan), PRRIITT misura 3.4 azione A, to InterMech (Division Acoustics and Vibrations - LAV), and by UNIFE funds.Peer reviewe
Neuromonitoring in intensive care: a new brain tissue probe for combined monitoring of intracranial pressure (ICP) cerebral blood flow (CBF) and oxygenation

BACKGROUND: the benefits of monitoring cerebral blood flow (CBF) in stroke patients are apparent. New techniques combining near infrared spectroscopy (NIRS) and indocyanine green (ICG) dye dilution to estimate cerebral hemodynamics are available. However, with transcutaneous NIRS and optodes applied over the skin, the signal is contaminated by extracerebral tissues. The objective is to develop a new brain tissue probe for combined monitoring of intracranial pressure (ICP), CBF and cerebral blood volume (CBV).\ud
\ud
METHODS: conventional intraparenchymal probes for ICP monitoring are supplied with optical fibers. The light is coupled into the brain tissue and collected after absorption and scattering with a light detector. Venous injections of 0.2 mg/kgbw ICG are performed. The mean transit time of ICG (mttICG), CBF and CBV are calculated.\ud
\ud
RESULTS: with a prototype of the probe in a first patient with subarachnoid hemorrhage 6 pairs of repetitive measurements were performed. Mean values were for mttICG 5.6 ± 0.2 s, CBF 22.3 ± 2.8 ml/100 g/min and CBV 2.1 ± 0.3 ml/100 g.\ud
\ud
CONCLUSIONS: NIR spectroscopy allows the synchronous determination of multiple parameters with one single device. By measurements in parallel with the NeMo Probe and NIRS optodes placed over the skin, new algorithms can be developed to subtract the extracerebral contamination from the NIRS signal
Designing and Adapting Service-based Systems: A Service Discovery Framework

This chapter describes a service discovery framework that has been developed within the EU 6th Framework projects SeCSE and Gredia. The framework supports design of service-based systems based on existing services and adaptation of service based systems during their execution due to different situations. It assumes services described from different perspectives and uses complex service discovery queries specified in a XML-based language that we have developed. The work is illustrated with the Cell Phone Operator case study
Approximate Implicitization of Space Curves

The process of implicitization generates an implicit representation of a curve or surface from a given parametric one. This process is potentially interesting for applications in Com- puter Aided Design, where the robustness and efficiency of intersection algorithm can be improved by simultaneously considering implicit and parametric representations. This pa- per gives an brief survey of the existing techniques for approximate implicitization of hyper surfaces. In addition it describes a framework for the approximate implicitization of space curves
Symbolic Analysis for Boundary Problems: From Rewriting to Parametrized
  Gr\"obner Bases

We review our algebraic framework for linear boundary problems (concentrating
on ordinary differential equations). Its starting point is an appropriate
algebraization of the domain of functions, which we have named
integro-differential algebras. The algebraic treatment of boundary problems
brings up two new algebraic structures whose symbolic representation and
computational realization is based on canonical forms in certain commutative
and noncommutative polynomial domains. The first of these, the ring of
integro-differential operators, is used for both stating and solving linear
boundary problems. The other structure, called integro-differential
polynomials, is the key tool for describing extensions of integro-differential
algebras. We use the canonical simplifier for integro-differential polynomials
for generating an automated proof establishing a canonical simplifier for
integro-differential operators. Our approach is fully implemented in the
Theorema system; some code fragments and sample computations are included.Comment: 54 page
Computer Algebra meets Finite Elements: an Efficient Implementation for
  Maxwell's Equations

We consider the numerical discretization of the time-domain Maxwell's
equations with an energy-conserving discontinuous Galerkin finite element
formulation. This particular formulation allows for higher order approximations
of the electric and magnetic field. Special emphasis is placed on an efficient
implementation which is achieved by taking advantage of recurrence properties
and the tensor-product structure of the chosen shape functions. These
recurrences have been derived symbolically with computer algebra methods
reminiscent of the holonomic systems approach.Comment: 16 pages, 1 figure, 1 table; Springer Wien, ISBN 978-3-7091-0793-
Social Semantic Network-Based Access Control

International audienceSocial networks are the basis of the so called Web 2.0, raising many new challenges to the research community. In particular, the ability of these networks to allow the users to share their own personal information with other people opens new issues concerning privacy and access control. Nowadays the Web has further evolved into the Social Semantic Web where social networks are integrated and enhanced by the use of semantic conceptual models, e.g., the ontologies, where the social information and links among the users become semantic information and links. In this paper, we discuss which are the benefits of introducing semantics in social network-based access control. In particular, we analyze and detail two approaches to manage the access rights of the social network users relying on Semantic Web languages only, and we highlight, thanks to these two proposals, what are pros and cons of introducing semantics in social networks access control. Finally, we report on the other existing approaches coupling semantics and access control in the context of social networks
Continuous quantitative monitoring of cerebral oxygen metabolism in neonates by ventilator-gated analysis of NIRS recordings

Oxidative stress during fetal development, delivery, or early postnatal life is a major cause of neuropathology, as both hypoxic and hyperoxic insults can significantly damage the developing brain. Despite the obvious need for reliable cerebral oxygenation monitoring, no technology currently exists to monitor cerebral oxygen metabolism continuously and noninvasively in infants at high risk for developing brain injury. Consequently, a rational approach to titrating oxygen supply to cerebral oxygen demand – and thus avoiding hyperoxic or hypoxic insults – is currently lacking. We present a promising method to close this crucial technology gap in the important case of neonates on conventional ventilators. By using cerebral near-infrared spectroscopy and signals from conventional ventilators, along with arterial oxygen saturation, we derive continuous (breath-by-breath) estimates of cerebral venous oxygen saturation, cerebral oxygen extraction fraction, cerebral blood flow, and cerebral metabolic rate of oxygen. The resultant estimates compare very favorably to previously reported data obtained by non-continuous and invasive means from preterm infants in neonatal critical care.National Institutes of Health (U.S.) (Grant R01EB001659)National Institutes of Health (U.S.) (Grant K24NS057568)National Institutes of Health (U.S.) (Grant R21HD056009
Pulse amplitude and Lempel-Ziv complexity of the cerebrospinal fluid pressure signal.

The complexity of the intracranial pressure (ICP) signal decreases with intracranial hypertension in children with acute brain injury as well as during infusion studies in adults with hydrocephalus. In this study we have analysed the pressure signal obtained in the lumbar subarachnoid space during infusion testing. The pulse amplitude rises when the ICP is increased by additional external volume. Our objective was to determine the relative influence of the pressure range and pulse amplitude on the loss of complexity observed during infusion-related intracranial hypertension
Perspectives of parameter and state estimation in paleoclimatology in Climate Change, Inferences from Paleoclimate and Regional Aspects, Proceedings of the Milutin Milankovitch 130th Anniversary Symposium

Past climates provide a means for evaluating the response of the climate system to large perturbations. Our ultimate goal is to constrain climate models rigorously by paleoclimate data. For illustration, we used a conceptual climate model (a classical energy balance model) and applied the so-called “adjoint method” to minimize the misfit between our model and sea-surface temperature data for the Last Glacial Maximum (LGM, between 19,000-23,000 years before present). The “adjoint model” (derivative code) was generated by an “adjoint compiler”. We optimized parameters controlling the thermal diffusion and the sensitivity of the outgoing longwave radiation to changes in the zonal-mean surface temperature and the atmospheric CO2 concentration. As a result, we estimated that an equilibrium climate sensitivity between 2.2 degC and 2.5 degC was consistent with the reconstructed glacial cooling, and we were able to infer structural deficits of the simple model where the fit to current observations and paleo data was not successful
Informative Value of Individual and Relational Data Compared Through Business-Oriented Community Detection

Despites the great interest caused by social networks in Business Science, their analysis is rarely performed in both a global and systematic way in this field. This could be explained by the fact their practical extraction is a difficult and costly task. One may ask if equivalent information could be retrieved from less expensive, individual data (i.e. describing single individuals instead of pairs). In this work, we try to address this question through group detection. We gather both types of data from a population of students, estimate groups separately using individual and relational data, and obtain sets of clusters and communities, respectively. We measure the overlap between clusters and communities, which turns out to be relatively weak. We also define a predictive model, allowing us to identify the most discriminant attributes for the communities, and to reveal the presence of a tenuous link between the relational and individual data. Our results seem to indicate both types of data convey considerably different information in this specific context, and can therefore be considered as complementary. To emphasize the interest of communities for Business Science, we also conduct an analysis based on hobbies and purchased brands
Creative Telescoping for Holonomic Functions

The aim of this article is twofold: on the one hand it is intended to serve
as a gentle introduction to the topic of creative telescoping, from a practical
point of view; for this purpose its application to several problems is
exemplified. On the other hand, this chapter has the flavour of a survey
article: the developments in this area during the last two decades are sketched
and a selection of references is compiled in order to highlight the impact of
creative telescoping in numerous contexts.Comment: Tutorial and survey article, 24 page
Pedestrians moving in dark: Balancing measures and playing games on
  lattices

We present two conceptually new modeling approaches aimed at describing the
motion of pedestrians in obscured corridors:
  * a Becker-D\"{o}ring-type dynamics
  * a probabilistic cellular automaton model.
  In both models the group formation is affected by a threshold. The
pedestrians are supposed to have very limited knowledge about their current
position and their neighborhood; they can form groups up to a certain size and
they can leave them. Their main goal is to find the exit of the corridor.
Although being of mathematically different character, the discussion of both
models shows that it seems to be a disadvantage for the individual to adhere to
larger groups. We illustrate this effect numerically by solving both model
systems. Finally we list some of our main open questions and conjectures
Stress modeling of multi level interconnect schemes for future deep submicron device generations

Copper and low dielctric constantant (k) materials are poised to become the dominant interconnect scheme for integrated circuits for the future because of the low resistance and capacitance that they offer which can improve circuit performance by more than 30% over conventional interconnect schemes. This paper addresses the thermomechanical stresses in the Cu/Low k interconnect scheme through numerical simulation and identifies the locations of maximum stress in the structure with view to providing information on the impact that different dielectric materials have on the stress distribution in the interfaces between metals and dielectric layers
Chiral dynamics in systems with strangeness

In this talk a brief review of several problems involving systems with strangeness is made. In the first place one shows how the Λ(1405), Λ(1670) and Σ(1620) states, for S=−1, and the Ξ(1620) for S=−2 are generated dynamically in the context of unitarized chiral perturbation theory. The results for the K¯N interaction are then used to evaluate the K−d scattering length. Results obtained for the kaon selfenergy in a nuclear medium within this approach, with application to K− atoms, are also mentioned. Finally a few words are said about recent developments in the weak decay of Λ hypernuclei and the puzzle of the Γn/Γp ratio
A Survey of Methods for Volumetric Scene Reconstruction from Photographs

Scene reconstruction, the task of generating a 3D model of a scene given multiple 2D photographs taken of the scene, is an old and difficult problem in computer vision. Since its introduction, scene reconstruction has found application in many fields, including robotics, virtual reality, and entertainment. Volumetric models are a natural choice for scene reconstruction. Three broad classes of volumetric reconstruction techniques have been developed based on geometric intersections, color consistency, and pair-wise matching. Some of these techniques have spawned a number of variations and undergone considerable refinement. This paper is a survey of techniques for volumetric scene reconstruction
Nucleon structure functions in a constituent quark scenario

Using a simple picture of the constituent quark as a composite system of point-like partons, we construct the polarized parton distributions by a convolution between constituent quark momentum distributions and constituent quark structure functions. We achieve good agreement with experiments in the unpolarized as well as in the polarized case, though a good description of the recent polarized neutron data requires the introduction of one more parameter. When our results are compared with similar calculations using non-composite constituent quarks, the accord with the experiments of the present scheme is impressive. We conclude that DIS data are consistent with a low energy scenario dominated by composite constituents of the nucleon
Recent developments in one and two pion production in elementary reactions and few-body systems

In this talk we cover several issues concerning pion production. The first one is the p p ----> p p pi^0 reaction where an alternative explanation based on the off shell extrapolation of the pi N amplitude is offered. A recent model for the gamma N ----> pi pi N reaction is presented and a new kind of exchange current is constructed from it which allows one to address problems like double Delta photoproduction from the deuteron. Finally the (gamma, pi pi) reaction in nuclei is studied and shown to be highly sensitive to the renormalization of the pions in nuclei
Odd pairs of cliques

A graph is Berge if it has no induced odd cycle on at least 5 vertices and no
complement of induced odd cycle on at least 5 vertices. A graph is perfect if
the chromatic number equals the maximum clique number for every induced
subgraph. Chudnovsky, Robertson, Seymour and Thomas proved that every Berge
graph either falls into some classical family of perfect graphs, or has a
structural fault that cannot occur in a minimal imperfect graph. A corollary of
this is the strong perfect graph theorem conjectured by Berge: every Berge
graph is perfect. An even pair of vertices in a graph is a pair of vertices
such that every induced path between them has even length. Meyniel proved that
a minimal imperfect graph cannot contain an even pair. So even pairs may be
considered as a structural fault. Chudnovsky et al. do not use them, and it is
known that some classes of Berge graph have no even pairs.
  The aim of this work is to investigate an "even-pair-like" notion that could
be a structural fault present in every Berge graph. An odd pair of cliques is a
pair of cliques $\{K_1, K_2\}$ such that every induced path from $K_1$ to $K_2$
with no interior vertex in $K_1 \cup K_2$ has odd length. We conjecture that
for every Berge graph $G$ on at least two vertices, either one of $G, \bar{G}$
has an even pair, or one of $G, \bar{G}$ has an odd pair of cliques. We
conjecture that a minimal imperfect graph has no odd pair of maximal cliques.
We prove these conjectures in some special cases. We show that adding all edges
between any 2 vertices of the cliques of an odd pair of cliques is an operation
that preserves perfectness
DFR Perturbative Quantum Field theory on Quantum Space Time, and Wick
  Reduction

We discuss the perturbative approach a` la Dyson to a quantum field theory
with nonlocal self-interaction :phi*...*phi:, according to Doplicher,
Fredenhagen and Roberts (DFR). In particular, we show that the Wick reduction
of non locally time--ordered products of Wick monomials can be performed as
usual, and we discuss a very simple Dyson diagram.Comment: 15 pages, pdf has active hyperlinks. To appear in the proceedings of
  the conference on "Rigorous quantum Field Theory", held at Saclay on July
  19-21, 2004, on the occasion of Jacques Bros' 70th birthda
Non-commutative Renormalization

A new version of scale analysis and renormalization theory has been found on
the non-commutative Moyal space. It could be useful for physics beyond the
standard model or for standard physics in strong external field. The good news
is that quantum field theory is better behaved on non-commutative than on
ordinary space: indeed it has no Landau ghost. Noncommutativity might therefore
be an alternative to supersymmetry. We review this rapidly growing subject.Comment: 82 pages, Poincare Seminar, updated and expanded version of
  arXiv:hep-th/070206
Massless scalar field in two-dimensional de Sitter universe

We study the massless minimally coupled scalar field on a two--dimensional de
Sitter space-time in the setting of axiomatic quantum field theory. We
construct the invariant Wightman distribution obtained as the renormalized
zero--mass limit of the massive one. Insisting on gauge invariance of the model
we construct a vacuum state and a Hilbert space of physical states which are
invariant under the action of the whole de Sitter group. We also present the
integral expression of the conserved charge which generates the gauge
invariance and propose a definition of dual field.Comment: 13 page
Celestial integration, stringy invariants, and Chern-Schwartz-MacPherson
  classes

We introduce a formal integral on the system of varieties mapping properly
and birationally to a given one, with value in an associated Chow group.
Applications include comparisons of Chern numbers of birational varieties, new
birational invariants, `stringy' Chern classes, and a `celestial' zeta function
specializing to the topological zeta function.
  In its simplest manifestation, the integral gives a new expression for
Chern-Schwartz-MacPherson classes of possibly singular varieties, placing them
into a context in which a `change of variable' formula holds.
  The formalism has points of contact with motivic integration.Comment: 11 pages, LaTe
Vertices and inflexions of plane sections of surfaces in R^3

We investigate the behaviour of vertices and inflexions on 1-parameter
families of curves on smooth surfaces in the 3-space, which include a singular
member.
  In particular, we discuss the context where the curves evolve as sections of
a smooth surface by parallel planes. More precisely we will trace the patterns
of inflexions and vertices (maxima and minima of curvature) on the sections of
a surface as the section passes through a tangential point.
  We also keep track on the evolution of the curvature of the curves at
vertices and control its limit when the vertices collapse at singular points.
  In particular, we cover all the generic cases, namely when the tangential
points are elliptic (A1), umbilic (A1), hyperbolic(A1), parabolic (A2) and cusp
of Gauss (A3) points.
  This has some applications in Computer vision and is also related to
interesting mathematical problems such as Legendrian collapse, foliations of
surfaces, the 4-vertex Theorem or in general the behaviour of vertices and
inflexions in parameter families of curves etc.Comment: v2: 22 pages, Latex. Added references and comments, 10 figures. Proof
  of main result improved, after discussions with Prof. Terry Wall. See also:
  http://www.liv.ac.uk/~pjgiblin/ or
  http://www.liv.ac.uk/~adiatta/diatta-giblin-surf-vertices.pd
An example of spectral phase transition phenomenon in a class of Jacobi
  matrices with periodically modulated weights

We consider self-adjoint unbounded Jacobi matrices with diagonal q_n=n and
weights \lambda_n=c_n n, where c_n is a 2-periodical sequence of real numbers.
The parameter space is decomposed into several separate regions, where the
spectrum is either purely absolutely continuous or discrete. This constitutes
an example of the spectral phase transition of the first order. We study the
lines where the spectral phase transition occurs, obtaining the following main
result: either the interval (-\infty;1/2) or the interval (1/2;+\infty) is
covered by the absolutely continuous spectrum, the remainder of the spectrum
being pure point. The proof is based on finding asymptotics of generalized
eigenvectors via the Birkhoff-Adams Theorem. We also consider the degenerate
case, which constitutes yet another example of the spectral phase transition