1,722,626 research outputs found
Commissioning of ROD boards for the entire ATLAS Pixel Detector
No full textThe ATLAS Experiment has reworked and upgraded some electronic DAQ chains during the 2013–2015 LHC shut down and an additional barrel layer has been inserted as part of the Pixel Detector: the Insertable B-Layer (IBL). The Layers 2 and 1 of the ATLAS Pixel Detector have also been upgraded, using the same Back Of Crate (BOC) and ReadOut-Driver (ROD) cards designed for IBL, while maintaining the front-end sensors unchanged. The two layers 2 and 1 are mentioned in the order that they have been upgraded, so Layer 2 first and then Layer 1, according to the bandwidth limitation as a function of the luminosity. Now the efforts focus on upgrading DAQ electronics of the B-layer and the Disks, again leaving the front-end detectors untouched. The Layer 2 and 1, which required 26 and 38 additional pairs of IBL BOC and ROD cards, have been taken data during 2017. The IBL boards can easily expand the bandwidth of the Pixel Layer 2 and 1 since a dedicated firmware has been provided to interface with the old detector. In particular, these layers read out the FE-I3 ASICs instead of the IBL FE-I4 chips. The same IBL BOC and ROD card configuration has been used for the upgrade of the B-Layer and Disks of the ATLAS Pixel Detector. In addition, the B-Layer and Disks share the same firmware in use for Layer 1 readout. The additional RODs have already been produced and tested. The plan was to have the readout upgrade of B-Layer and Disks commissioned by the first technical stop in January-March 2018. Thus, eventually, the entire Pixel Detector of ATLAS will share the same hardware readout chain, but the firmware will depend on the type of front-end sensor and modularity
Scale invariant forces in one-dimensional shuffled lattices
No full textWe present a detailed and exact study of the probability density function P(F) of the total force F acting on a point particle belonging to a perturbed lattice of identical point sources of a power-law pair interaction. The main results concern the large-F tail of P(F) for which two cases are mainly distinguished: (i) Gaussian-like fast decreasing P(F) for lattice with perturbations forbidding any pair of particles to be found arbitrarily close to one each other and (ii) Levy-like power-law decreasing P(F) when this possibility is instead permitted. It is important to note that in the second case the exponent of the power-law tail of P(F) is the same for all perturbations (apart from very singular cases) and is in a one-to-one correspondence with the exponent characterizing the behavior of the pair interaction with the distance between the two particles
Invasion percolation on a tree and queueing models
No full textWe study the properties of the Barabasi model of queuing [A.-L. Barabasi, Nature (London) 435, 207 (2005); J. G. Oliveira and A.-L. Barabasi, Nature (London) 437, 1251 (2005)] in the hypothesis that the number of tasks grows with time steadily. Our analytical approach is based on two ingredients. First we map exactly this model into an invasion percolation dynamics on a Cayley tree. Second we use the theory of biased random walks. In this way we obtain the following results: the stationary-state dynamics is a sequence of causally and geometrically connected bursts of execution activities with scale-invariant size distribution. We recover the correct waiting-time distribution P(W)(tau)similar to tau(-3/2) at the stationary state (as observed in different realistic data). Finally we describe quantitatively the dynamics out of the stationary state quantifying the power-law slow approach to stationarity both in single dynamical realization and in average. These results can be generalized to the case of a stochastic increase in the queue length in time with limited fluctuations. As a limit case we recover the situation in which the queue length fluctuates around a constant average value
Is there a future for anti-cd38 antibody therapy in systemic autoimmune diseases?
Full text linkCD38 is a type II glycoprotein highly expressed on plasmablasts, short-lived and long-lived plasma cells, but weakly expressed on other lymphoid cells, myeloid cells and non-hematopoietic cells. This expression pattern makes CD38 an interesting target for a targeted therapy aiming to deplete antibody-producing plasma cells. We present data suggesting that anti-CD38 therapy may be effective for the prevention at the preclinical stage and for the treatment of established autoimmune diseases, such as systemic lupus erythematosus, systemic sclerosis, Sjögren’s syndrome and anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis. Given the high unmet need for efficacious disease-modifying treatment in these diseases, studies are warranted to determine if anti-CD38 antibody-based therapies may delay or prevent the disease progression of systemic autoimmune diseases
Complexity in cosmic structures
No full textWe discuss correlation properties of a general mass density field introducing a classification of structures based on their complexity. Standard cosmological models for primordial mass fluctuations are characterized by a sort of large-scale stochastic order, that we call super-homogeneity to highlight the fact that mass fluctuations increase as a function of scale in the slowest-possible way for any stochastic mass field. On the other hand, the galaxy spatial distribution show complex structures with a high degree of inhomogeneity and fractal-like spatial correlations up to some relevant cosmological scale. The theoretical problem of cosmological structure formation should then explain the growth of strongly correlated and non-linear structures from the very uniform field of density fluctuations given as standard initial condition. (C) 2004 Elsevier B.V. All rights reserved
Peaks in the CMBR power spectrum. I. Mathematical analysis of the associated real space features
No full textThe purpose of our study is to understand the mathematical origin in real space of modulated and damped sinusoidal peaks observed in cosmic microwave background radiation anisotropies. We use the theory of the Fourier transform to connect localized features of the two-point correlation function in real space to oscillations in the power spectrum. We also illustrate analytically and by means of Monte Carlo simulations the angular correlation function for distributions of filled disks with fixed or variable radii capable of generating oscillations in the power spectrum. While the power spectrum shows repeated information in the form of multiple peaks and oscillations, the angular correlation function offers a more compact presentation that condenses all the information of the multiple peaks into a localized real space feature. We have seen that oscillations in the power spectrum arise when there is a discontinuity in a given derivative of the angular correlation function at a given angular distance. These kinds of discontinuities do not need to be abrupt in an infinitesimal range of angular distances but may also be smooth, and can be generated by simply distributing excesses of antenna temperature in filled disks affixed or variable radii on the sky, provided that there is a non-null minimum radius and/or the maximum radius is constrained. (C) 2012 Elsevier B.V. All rights reserved
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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