CMOS-3D smart imager architectures for feature detection

This paper reports a multi-layered smart image sensor architecture for feature extraction based on detection of interest points. The architecture is conceived for 3-D integrated circuit technologies consisting of two layers (tiers) plus memory. The top tier includes sensing and processing circuitry aimed to perform Gaussian filtering and generate Gaussian pyramids in fully concurrent way. The circuitry in this tier operates in mixed-signal domain. It embeds in-pixel correlated double sampling, a switched-capacitor network for Gaussian pyramid generation, analog memories and a comparator for in-pixel analog-to-digital conversion. This tier can be further split into two for improved resolution; one containing the sensors and another containing a capacitor per sensor plus the mixed-signal processing circuitry. Regarding the bottom tier, it embeds digital circuitry entitled for the calculation of Harris, Hessian, and difference-of-Gaussian detectors. The overall system can hence be configured by the user to detect interest points by using the algorithm out of these three better suited to practical applications. The paper describes the different kind of algorithms featured and the circuitry employed at top and bottom tiers. The Gaussian pyramid is implemented with a switched-capacitor network in less than 50 μs, outperforming more conventional solutions.Xunta de Galicia 10PXIB206037PRMinisterio de Ciencia e Innovación TEC2009-12686, IPT-2011-1625-430000Office of Naval Research N00014111031

Cops or robbers - a bistable society

The norm game described by Axelrod in 1985 was recently treated with the master equation formalism. Here we discuss the equations, where {\it i)} those who break the norm cannot punish and those who punish cannot break the norm, {\it ii)} the tendency to punish is suppressed if the majority breaks the norm. The second mechanism is new. For some values of the parameters the solution shows the saddle-point bifurcation. Then, two stable solutions are possible, where the majority breaks the norm or the majority punishes. This means, that the norm breaking can be discontinuous, when measured in the social scale. The bistable character is reproduced also with new computer simulations on the Erd{\H o}s--R\'enyi directed network.Comment: 8 pages, 2 figures. Some misleading sentences are removed from section

All-optical attoclock: accessing exahertz dynamics of optical tunnelling through terahertz emission

The debate regarding attosecond dynamics of optical tunneling has so far been focused on time delays associated with electron motion through the potential barrier created by intense ionizing laser fields and the atomic core. Compelling theoretical and experimental arguments have been put forward to advocate the polar opposite views, confirming or refuting the presence of tunnelling time delays. Yet, such delay, whether present or ot, is but a single quantity characterizing the tunnelling wavepacket; the underlying dynamics are richer. Here we propose to complement photo-electron detection with detecting light, focusing on the so-called Brunel adiation -- the near-instantaneous nonlinear optical response triggered by the tunnelling event. Using the combination of single-color and two-color driving fields, we determine not only the ionization delays, but also the re-shaping of the tunnelling wavepacket as it emerges from the classically forbidden region. Our work introduces a new type of attoclock for optical tunnelling, one that is based on measuring light rather than photo-electrons. All-optical detection paves the way to time-resolving multiphoton transitions across bandgaps in solids, on the attosecond time-scale

Aged B cells alter immune regulation of allografts in mice

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134428/1/eji3757-sup-0001-PRC.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134428/2/eji3757_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134428/3/eji3757.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134428/4/eji3757-sup-0002-figure1-3.pd

Effects of parasite and historic driven selection on the diversity and structure of a MHC-II gene in a small mammal species (Peromyscus leucopus) undergoing range expansion.

Abstract Genetic diversity may decrease from the centre to the margin of a species distribution range due to neutral stochastic processes. Selection may also alter genetic diversity in non-neutral markers, such as genes associated with the immune system. Both neutral processes and selection on the immune system are thus expected to affect the spatial distribution of such markers, but the relative strength of each has been scarcely studied. Here, we compared the diversity of a neutral marker (mitochondrial cytochrome b)and a selected marker (DRB gene from the MHC-II), in eastern-North American populations of white-footed mice (Peromyscus leucopus), a species known for its role of main reservoir of the Lyme disease. We observed distinct phylogeographic patterns with these two markers, which may be the result of selection pressure acting upon the DRB gene. As predicted by the central marginal hypothesis, we observed a loss of neutral genetic diversity toward the margin of the species distribution. A decrease in diversity was also observed for the DRB gene, likely due to genetic drift and positive selection operated by helminth parasites. Such a loss in genetic diversity at the range margin may slow down the ongoing expansion of P. leucopus, by counterbalancing the effect of global warming on the mouse survival at higher latitude