Université catholique de Louvain

About: Université catholique de Louvain is a education organization based out in Louvain-la-Neuve, Belgium. It is known for research contribution in the topics: Population & Catalysis. The organization has 25319 authors who have published 57360 publications receiving 2172080 citations. The organization is also known as: University of Louvain & UCLouvain.

Robust 1-Bit Compressive Sensing via Binary Stable Embeddings of Sparse Vectors

Abstract: The Compressive Sensing (CS) framework aims to ease the burden on analog-to-digital converters (ADCs) by reducing the sampling rate required to acquire and stably recover sparse signals. Practical ADCs not only sample but also quantize each measurement to a finite number of bits; moreover, there is an inverse relationship between the achievable sampling rate and the bit depth. In this paper, we investigate an alternative CS approach that shifts the emphasis from the sampling rate to the number of bits per measurement. In particular, we explore the extreme case of 1-bit CS measurements, which capture just their sign. Our results come in two flavors. First, we consider ideal reconstruction from noiseless 1-bit measurements and provide a lower bound on the best achievable reconstruction error. We also demonstrate that i.i.d. random Gaussian matrices describe measurement mappings achieving, with overwhelming probability, nearly optimal error decay. Next, we consider reconstruction robustness to measurement errors and noise and introduce the Binary $\epsilon$-Stable Embedding (B$\epsilon$SE) property, which characterizes the robustness measurement process to sign changes. We show the same class of matrices that provide almost optimal noiseless performance also enable such a robust mapping. On the practical side, we introduce the Binary Iterative Hard Thresholding (BIHT) algorithm for signal reconstruction from 1-bit measurements that offers state-of-the-art performance.

Quantifying the evolution of individual scientific impact

Abstract: Are there quantifiable patterns behind a successful scientific career? Sinatra et al. analyzed the publications of 2887 physicists, as well as data on scientists publishing in a variety of fields. When productivity (which is usually greatest early in the scientist's professional life) is accounted for, the paper with the greatest impact occurs randomly in a scientist's career. However, the process of generating a high-impact paper is not an entirely random one. The authors developed a quantitative model of impact, based on an element of randomness, productivity, and a factor Q that is particular to each scientist and remains constant during the scientist's career. Science , this issue p. [596][1] [1]: http://www.sciencemag.org/content/354/6312/aaf5239.full

Diffusion-Weighted Imaging Tractography-Based Parcellation of the Human Parietal Cortex and Comparison with Human and Macaque Resting-State Functional Connectivity

Abstract: Despite the prominence of parietal activity in human neuroimaging investigations of sensorimotor and cognitive processes, there remains uncertainty about basic aspects of parietal cortical anatomical organization. Descriptions of human parietal cortex draw heavily on anatomical schemes developed in other primate species, but the validity of such comparisons has been questioned by claims that there are fundamental differences between the parietal cortex in humans and other primates. A scheme is presented for parcellation of human lateral parietal cortex into component regions on the basis of anatomical connectivity and the functional interactions of the resulting clusters with other brain regions. Anatomical connectivity was estimated using diffusion-weighted magnetic resonance image (MRI)-based tractography, and functional interactions were assessed by correlations in activity measured with functional MRI at rest. Resting-state functional connectivity was also assessed directly in the rhesus macaque lateral parietal cortex in an additional experiment, and the patterns found reflected known neuroanatomical connections. Cross-correlation in the tractography-based connectivity patterns of parietal voxels reliably parcellated human lateral parietal cortex into 10 component clusters. The resting-state functional connectivity of human superior parietal and intraparietal clusters with frontal and extrastriate cortex suggested correspondences with areas in macaque superior and intraparietal sulcus. Functional connectivity patterns with parahippocampal cortex and premotor cortex again suggested fundamental correspondences between inferior parietal cortex in humans and macaques. In contrast, the human parietal cortex differs in the strength of its interactions between the central inferior parietal lobule region and the anterior prefrontal cortex.

Alternate interpretation of the Messinian salinity crisis: Controversy resolved?

Abstract: A high-resolution chronology of the Mediterranean Messinian salinity crisis is proposed. Two types of evaporite deposition may be distinguished: those in marginal areas vs. those in basinal ones. Their diachroneity is deduced from the stratigraphic relationships linking these evaporites to a major Messinian erosional surface, A two-step model is proposed for the evolution of the salinity crisis through time. During the first phase (from 5.75 to 5.60 Ma), the deposition of marginal evaporites took place in response to a modest sea-level fall; in the second interval (from 5.60 to 5.32 Ma), the Mediterranean basin became isolated. During this later period, the deposition of basinal evaporites and the cutting of the Mediterranean canyons took place.

Complete inventory of the yeast ABC proteins.

Abstract: The complete sequence of the yeast genome predicts the existence of 29 proteins belonging to the ubiquitous ATP-binding cassette (ABC) superfamily. Using binary comparison, phylogenetic classification and detection of conserved amino acid residues, the yeast ABC proteins have been classified in a total of six clusters, including ten subclusters of distinct predicted topology and presumed distinct function. Study of the yeast ABC proteins provides insight into the physiological function and biochemical mechanisms of their human homologues, such as those involved in cystic fibrosis, adrenoleukodystrophy, Zellweger syndrome, multidrug resistance and the antiviral activity of interferons.