Search results for "numerical"
showing 10 items of 2002 documents
Preattentive and attentive responses to changes in small numerosities of tones in adult humans
2016
The brain hosts a primitive number sense to non-symbolically represent numerosities of objects or events. Small exact numerosities (~4 or less) can be individuated in parallel. In contrast, large numerosities (more than ~4) can only be approximated. However, whether small numerosities can be approximated without their parallel individuation remains unclear. Parallel individuation is suggested to be an attentive process and numerical approximation an automatic process. We, therefore, tested whether small numerosities can be represented preattentively. We recorded adult humans׳ event-related potentials (ERPs) and behavioral responses to 300-ms sequences of six tones (each of either 440 Hz or …
Perceiving numbers alters time perception.
2008
The representation of time, space and numbers are strictly linked in the primate's cognitive system. Here we show that merely looking at number symbols biases a temporal judgment on their duration depending upon the number's magnitude. In a first experiment, a group of healthy subjects was submitted to a time estimation task, requiring to judge whether the duration of a test stimulus was longer or shorter than that of a previous reference fixed stimulus (digit 5; duration 300 ms). Test stimuli were the digits 1, 5 and 9 ranging between 250 and 350 ms. The main results showed that temporal perception was biased according to the magnitude expressed by the digit: low digits (i.e. 1) leading to…
Effect of Recombinant Zoster Vaccine on Incidence of Herpes Zoster After Autologous Stem Cell Transplantation A Randomized Clinical Trial
2019
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Measuring change in health care equity using small-area administrative data – Evidence from the English NHS 2001–2008
2012
This study developed a method for measuring change in socio-economic equity in health care utilisation using small-area level administrative data. Our method provides more detailed information on utilisation than survey data but only examines socio-economic differences between neighbourhoods rather than individuals. The context was the English NHS from 2001 to 2008, a period of accelerated expenditure growth and pro-competition reform. Hospital records for all adults receiving non-emergency hospital care in the English NHS from 2001 to 2008 were aggregated to 32,482 English small areas with mean population about 1500 and combined with other small-area administrative data. Regression models …
An explicit unconditionally stable numerical solution of the advection problem in irrotational flow fields.
2004
A new methodology for the Eulerian numerical solution of the advection problem is proposed. The methodology is based on the conservation of both the zero- and the first-order spatial moments inside each element of the computational domain and leads to the solution of several small systems of ordinary differential equations. Since the systems are solved sequentially (one element after the other), the method can be classified as explicit. The proposed methodology has the following properties: (1) it guarantees local and global mass conservation, (2) it is unconditionally stable, and (3) it applies second-order approximation of the concentration and its fluxes inside each element. Limitation o…
Effects of Air Tightness Tests on Steel Thin-Wall Box Structures with Circular and Rectangular Cross Sections
2019
In this paper, the effects of air tightness tests on steel box structures with rectangular or circular cross sections typical of port cranes (legs, arms, and crosspieces) are analyzed. Legs and arms are generally made with elements with profiles having a square or rectangular cross section, while the diagonal struts are made with profiles having circular cross sections. To verify the air tightness of these elements, a necessary requirement to protect them from corrosion if they are not protected with other protection techniques, air tightness tests are performed. These tests, in the framework of durability tests, must be carried out while maintaining the structure elasticity well below the …
Rationalizability of square roots
2021
Abstract Feynman integral computations in theoretical high energy particle physics frequently involve square roots in the kinematic variables. Physicists often want to solve Feynman integrals in terms of multiple polylogarithms. One way to obtain a solution in terms of these functions is to rationalize all occurring square roots by a suitable variable change. In this paper, we give a rigorous definition of rationalizability for square roots of ratios of polynomials. We show that the problem of deciding whether a single square root is rationalizable can be reformulated in geometrical terms. Using this approach, we give easy criteria to decide rationalizability in most cases of square roots i…
A note on cocharacter sequence of Jordan upper triangular matrix algebra
2016
Let UJn(F) be the Jordan algebra of n × n upper triangular matrices over a field F of characteristic zero. This paper is devoted to the study of polynomial identities satisfied by UJ2(F) and UJ3(F). In particular, the goal is twofold. On one hand, we complete the description of G-graded polynomial identities of UJ2(F), where G is a finite abelian group. On the other hand, we compute the Gelfand–Kirillov dimension of the relatively free algebra of UJ2(F) and we give a bound for the Gelfand–Kirillov dimension of the relatively free algebra of UJ3(F).
Multiplicity results for a class of asymmetric weakly coupled systems of second order ordinary differential equations
2005
We prove the existence and multiplicity of solutions to a two-point boundary value problem associated to a weakly coupled system of asymmetric second-order equations. Applying a classical change of variables, we transform the initial problem into an equivalent problem whose solutions can be characterized by their nodal properties. The proof is developed in the framework of the shooting methods and it is based on some estimates on the rotation numbers associated to each component of the solutions to the equivalent system.
The diamond partial order for strong Rickart rings
2016
The diamond partial order has been first introduced for matrices, and then discussed also in the general context of *-regular rings. We extend this notion to Rickart rings, and state various properties of the diamond order living on the so-called strong Rickart rings. In particular, it is compared with the weak space preorder and the star order; also existence of certain meets and joins under diamond order is discussed.