Defective pancreatic beta-cell glycolytic signaling in hepatocyte nuclear factor-1alpha-deficient mice

Mutations in the hepatocyte nuclear factor-1alpha (HNF-1alpha) gene cause maturity onset diabetes of the young type 3, a form of type 2 diabetes mellitus. In mice lacking the HNF-1alpha gene, insulin secretion and intracellular calcium ([Ca2+]i) responses were impaired following stimulation with nutrient secretagogues such as glucose and glyceraldehyde but normal with non-nutrient stimuli such as potassium chloride. Patch clamp recordings revealed ATP-sensitive K+ currents (KATP) in beta-cells that were insensitive to suppression by glucose but normally sensitive to ATP. Exposure to mitochondrial substrates suppressed KATP, elevated [Ca2+]i, and corrected the insulin secretion defect. NAD(P)H responses to glucose were substantially reduced, and inhibitors of glycolytic NADH generation reproduced the mutant phenotype in normal islets. Flux of glucose through glycolysis in islets from mutant mice was reduced, as a result of which ATP generation in response to glucose was impaired. We conclude that hepatocyte nuclear factor-1alpha diabetes results from defective beta-cell glycolytic signaling, which is potentially correctable using substrates that bypass the defect.     

Optimal workload-based weighted wavelet synopses

In recent years wavelets were shown to be effective data synopses. We are concerned with the problem of finding efficiently wavelet synopses for massive data sets, in situations where information about query workload is available. We present linear time, I/O optimal algorithms for building optimal workload-based wavelet synopses for point queries. The synopses are based on a novel construction of weighted inner products and use weighted wavelets that are adapted to those products. The synopses are optimal in the sense that the subset of retained coefficients is the best possible for the bases in use with respect to either the mean-squared absolute or relative errors. For the latter, this is the first optimal wavelet synopsis even for the regular, non-workload-based case. Experimental results demonstrate the advantage obtained by the new optimal wavelet synopses.     

Anomaly detection in web documents using crisp and fuzzy-based cosine clustering methodology

Cluster analysis is a primary tool for detecting anomalous behavior in real-world data such as web documents, medical records of patients or other personal data. Most existing methods for document clustering are based on the classical vector-space model, which represents each document by a fixed-size vector of weighted key terms often referred to as key phrases. Since vector representations of documents are frequently very sparse, inverted files are used to prevent a tremendous computational overload which may be caused in large and diverse document collections such as pages downloaded from the World Wide Web. In order to reduce computation costs and space complexity, many popular methods for clustering web documents, including those using inverted files, usually assume a relatively small prefixed number of clusters.We propose several new crisp and fuzzy approaches based on the cosine similarity principle for clustering documents that are represented by variable-size vectors of key phrases, without limiting the final number of clusters. Each entry in a vector consists of two fields. The first field refers to a key phrase in the document and the second denotes an importance weight associated with this key phrase within the particular document. Removing the restriction on the total number of clusters, may moderately increase computing costs but on the other hand improves the method’s performance in classifying incoming vectors as normal or abnormal, based on their similarity to the existing clusters. All the procedures represented in this work are characterized by two features: (a) the number of clusters is not restricted by some relatively prefixed small number, i.e., an arbitrary new incoming vector which is not similar to any of the existing cluster centers necessarily starts a new cluster and (b) a vector with multiple appearance n in the training set is counted as n distinct vectors rather than a single vector. These features are the main reasons for the high quality performance of the proposed algorithms. We later describe them in detail and show their implementation in a real-world application from the area of web activity monitoring, in particular, by detecting anomalous documents downloaded from the internet by users with abnormal information interests.     

A lower bound on the period length of a distributed scheduler

Ad-scheduling of a graphG is a sequence of rounds, each consisting of some of the nodes of the graph, such that the distance between any two nodes participating in the same round is greater thand. Ad-scheduler is a protocol that determines ad-scheduling ofG. A 1-scheduler is applicable to process scheduling in a resource-sharing system, and to proper communication scheduling of the half-duplex model in communication networks. A 2-scheduler can be used as a collision-free protocol for radio networks.In this paper a simpled-scheduler is analyzed. We first discuss basic properties of this scheduling, and give a complete characterization of this scheduling for trees and cycles. We study the period length of this scheduling, and the main result is a worst-case exponential lower bound for this length.The research of Shmuel Zaks was supported by the Fund for Research in Electronics, Computers, and Communications adminstered by the Israeli Academy of Sciences and Humanities.     

Dynamic memory processes in retrieving answers to questions: Recall failures, judgments of knowing, and acquisition of information.

Three experiments were conducted to show that engaging in an effort to answer a question markedly influences the processing of information subsequently encountered in the environment. On each of 2 successive days, participants were given a definition test that involved the recall of rare English words cued by their definitions. A lexical-decision task was administered between the 2 definition tests; the timing of the lexical-decision task varied across experiments. A strong target-to-definition priming effect occurred such that prior exposure to words during the lexical-decision task increased their likelihood of being recalled in the final definition test. It also appears that earlier attempts to answer questions affected the acquisition of relevant new material in long-term memory. The role of these priming effects is discussed with respect to the process of updating memory representations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inferring region salience from binary and gray-level images

We introduce a method that uses contour fragments to highlight regions of interest. Our method obtains as input either a binary image or the gradient map of a gray-level image. It produces a saliency map that reflects for every point in the image our belief that it belongs to a salient region. Saliency is determined by criteria such as closure, convexity, and size. In addition, gaps in the boundaries of regions diminish their saliency. Explicit scale parameter determines the size of interest. The method is implemented by a convolution of the input edge image with a linear filter that specifies the region of influence of a contour point over the image. Experiments demonstrate the utility of the method for saliency and segmentation.     

Fast direct solution of 3-D scattering problems via nonuniform grid-based matrix compression

A fast non-iterative algorithm for the solution of large 3-D acoustic scattering problems is presented. The proposed approach can be used in conjunction with the conventional boundary element discretization of the integral equations of acoustic scattering. The algorithm involves domain decomposition and uses the nonuniform grid (NG) approach for the initial compression of the interactions between each subdomain and the rest of the scatterer. These interactions, represented by the off-diagonal blocks of the boundary element method matrix, are then further compressed while constructing sets of interacting and local basis and testing functions. The compressed matrix is obtained by eliminating the local degrees of freedom through the Schur's complement-based technique procedure applied to the diagonal blocks. In the solution process, the interacting unknowns are first determined by solving the compressed system equations. Subsequently, the local degrees of freedom are determined for each subdomain. The proposed technique effectively reduces the oversampling typically needed when using low-order discretization techniques and provides significant computational savings.     

A CMOS low noise amplifier with integrated front-side micromachined inductor

The paper presents the design and characterization of a low noise amplifier (LNA) in a 0.18 μm CMOS process with a novel micromachined integrated stacked inductor. The inductor is released from the silicon substrate by a low-cost CMOS compatible dry front-side micromachining process that enables higher inductor quality factor and self-resonance frequency. The post-processed micromachined inductor is used in the matching network of a single stage cascode 4 GHz LNA to improve its RF performance. This study compares performance of the fabricated LNA prior to and after post-processing of the inductor. The measurement results show a 0.5 dB improvement in the minimum noise figure and a 1 dB increase in gain, while good input matching is maintained. These results show that the novel low-cost CMOS compatible front-side dry micromachining process reported here significantly improves performance and is very promising for System-On-Chip (SOC) applications.     

Stabilization of Ni(I)(1,4,8,11-tetraazacyclotetradecane)+ in a Sol-Gel Matrix: It's Plausible Use in Catalytic Processes

Monovalent nickel is used as a catalyst in a diversity of important chemical systems due to its properties as a strong reducing agent. However, monovalent nickel is unstable in homogeneous systems; its lifetime is very short, and therefore, its efficiency as a catalyst is quite limited. In this article, we demonstrate the catalytic capabilities of Ni(I)(1,4,8,11-tetraazacyclotetradecane)⁺ as a reducing and catalytic agent by its entrapment in the silica sol gel matrix. The EPR results indicate that the sol-gel matrix plays two roles: it inhibits the common mechanism of Ni(I)L⁺ decomposition in aqueous solutions, and it also facilitates its functionality as a heterogeneous catalyst, by stabilizing it for at least several hours. The activity of Ni(I)L⁺ which is entrapped within the matrix, was studied by reducing 2,2-Bis(bromomethyl)-1,3-Propanediol and I₃⁻. The results indicate that Ni(I)L⁺/Ni(III)L−H²⁺ acts as a good reducing agent. These results have important implications for a variety of essential catalytic reactions by shedding light on a new feature of sol-gel matrices and their use as active species stabilizers.