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Search Results: 1 - 10 of 1699 matches for " Ohad Bar Siman Tov "
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Developing an Evolutionary Algorithm to Search for an Optimal Multi-Mother Wavelet Packets Combination  [PDF]
Ohad Bar Siman Tov, J. David Schaffer, Kenneth J. McLeod
Journal of Biomedical Science and Engineering (JBiSE) , 2015, DOI: 10.4236/jbise.2015.87043
Abstract: The wavelet transform is a popular analysis tool for non-stationary data, but in many cases, the choice of the mother wavelet and basis set remains uncertain, particularly when dealing with physiological data. Furthermore, the possibility exists for combining information from numerous mother wavelets so as to exploit different features from the data. However, the combinatorics become daunting given the large number of basis sets that can be utilized. Recent work in evolutionary computation has produced a subset selection genetic algorithm specifically aimed at the discovery of small, high-performance, subsets from among a large pool of candidates. Our aim was to apply this algorithm to the task of locating subsets of packets from multiple mother wavelet decompositions to estimate cardiac output from chest wall motions while avoiding the computational cost of full signal reconstruction. We present experiments which show how a continuous assessment metric can be extracted from the wavelets coefficients, but the dual-objective nature of the algorithm (high accuracy with small feature sets) imposes a need to restrict the sensitivity of the continuous accuracy metric in order to achieve the small subset size desired. A possibly subtle tradeoff seems to be needed to meet the dual objectives.
Evaluation of Uncertainties Related to the Near Field Model of Geological Repository for Spent Nuclear Fuel  [PDF]
Dana Barátová, Vladimír Ne?as
World Journal of Engineering and Technology (WJET) , 2015, DOI: 10.4236/wjet.2015.33C024

In Slovakia, a direct disposal of spent nuclear fuel in a deep geological repository within the country after a certain period of interim storage is a preferred option. This paper briefly describes near field model of radionuclide migration developed in GoldSim simulation code environment and analyses the calculated results on time-dependent release rates of safety relevant radionuclides. Given the fact that GoldSimalso enables to perform probabilistic simulations using the Monte Carlo method, a probabilistic approach was chosen to assess the influence of selected near field parameter uncertainties related to radionuclide migration on the radionuclide release rates from the bentonite buffer to the surrounding host rock. Based on the results, release rates of nuclides which exceed their solubility limits are effectively lowered and many of nuclides are significantly sorbed on the buffer material. It can be seen that the variance of the total release rate in the case of solubility uncertainty is almost two orders of magnitude within a long period of time.

A New Nuclear Function of the Entamoeba histolytica Glycolytic Enzyme Enolase: The Metabolic Regulation of Cytosine-5 Methyltransferase 2 (Dnmt2) Activity
Ayala Tovy,Rama Siman Tov,Ricarda Gaentzsch,Mark Helm,Serge Ankri
PLOS Pathogens , 2010, DOI: 10.1371/journal.ppat.1000775
Abstract: Cytosine-5 methyltransferases of the Dnmt2 family function as DNA and tRNA methyltransferases. Insight into the role and biological significance of Dnmt2 is greatly hampered by a lack of knowledge about its protein interactions. In this report, we address the subject of protein interaction by identifying enolase through a yeast two-hybrid screen as a Dnmt2-binding protein. Enolase, which is known to catalyze the conversion of 2-phosphoglycerate (2-PG) to phosphoenolpyruvate (PEP), was shown to have both a cytoplasmatic and a nuclear localization in the parasite Entamoeba histolytica. We discovered that enolase acts as a Dnmt2 inhibitor. This unexpected inhibitory activity was antagonized by 2-PG, which suggests that glucose metabolism controls the non-glycolytic function of enolase. Interestingly, glucose starvation drives enolase to accumulate within the nucleus, which in turn leads to the formation of additional enolase-E.histolytica DNMT2 homolog (Ehmeth) complex, and to a significant reduction of the tRNAAsp methylation in the parasite. The crucial role of enolase as a Dnmt2 inhibitor was also demonstrated in E.histolytica expressing a nuclear localization signal (NLS)-fused-enolase. These results establish enolase as the first Dnmt2 interacting protein, and highlight an unexpected role of a glycolytic enzyme in the modulation of Dnmt2 activity.
Glucose Starvation Boosts Entamoeba histolytica Virulence
Ayala Tovy,Rivka Hertz,Rama Siman-Tov,Sylvie Syan,Daniela Faust,Nancy Guillen,Serge Ankri
PLOS Neglected Tropical Diseases , 2011, DOI: 10.1371/journal.pntd.0001247
Abstract: The unicellular parasite, Entamoeba histolytica, is exposed to numerous adverse conditions, such as nutrient deprivation, during its life cycle stages in the human host. In the present study, we examined whether the parasite virulence could be influenced by glucose starvation (GS). The migratory behaviour of the parasite and its capability to kill mammalian cells and to lyse erythrocytes is strongly enhanced following GS. In order to gain insights into the mechanism underlying the GS boosting effects on virulence, we analyzed differences in protein expression levels in control and glucose-starved trophozoites, by quantitative proteomic analysis. We observed that upstream regulatory element 3-binding protein (URE3-BP), a transcription factor that modulates E.histolytica virulence, and the lysine-rich protein 1 (KRiP1) which is induced during liver abscess development, are upregulated by GS. We also analyzed E. histolytica membrane fractions and noticed that the Gal/GalNAc lectin light subunit LgL1 is up-regulated by GS. Surprisingly, amoebapore A (Ap-A) and cysteine proteinase A5 (CP-A5), two important E. histolytica virulence factors, were strongly down-regulated by GS. While the boosting effect of GS on E. histolytica virulence was conserved in strains silenced for Ap-A and CP-A5, it was lost in LgL1 and in KRiP1 down-regulated strains. These data emphasize the unexpected role of GS in the modulation of E.histolytica virulence and the involvement of KRiP1 and Lgl1 in this phenomenon.
Una franquicia llamada Louvre: Museo Louvre en Abu Dhabi, Jean Nouvel, 2013
Siman, Adolfo
DC PAPERS : Revista de Crítica y Teoría de la Arquitectura , 2010,
Improvement on Parameters of Algebraic-Geometry Codes from Hermitian Curves
Siman Yang
Mathematics , 2007,
Abstract: Motivated by Xing's method [7], we show that there exist [n,k,d] linear Hermitian codes over F_{q^2} with k+d>=n-3 for all sufficiently large q. This improves the asymptotic bound of Algebraic-Geometry codes from Hermitian curves given in [9,10].
A Note on an Asymptotically Good Tame Tower
Siman Yang
Mathematics , 2007,
Abstract: The explicit construction of function fields tower with many rational points relative to the genus in the tower play a key role for the construction of asymptotically good algebraic-geometric codes. In 1997 Garcia, Stichtenoth and Thomas [6] exhibited two recursive asymptotically good Kummer towers over any non-prime field. Wulftange determined the limit of one tower in his PhD thesis [13]. In this paper we determine the limit of another tower [14].
On the Neron-Severi groups of fibered varieties
Siman Wong
Mathematics , 2001,
Abstract: We apply Tate's conjecture on algebraic cycles to study the N\'eron-Severi groups of varieties fibered over a curve. This is inspired by the work of Rosen and Silverman, who carry out such an analysis to derive a formula for the rank of the group of sections of an elliptic surface. For a semistable fibered surface, under Tate's conjecture we derive a formula for the rank of the group of sections of the associated Jacobian fibration. For fiber powers of a semistable elliptic fibration $E --> C$, under Tate's conjecture we give a recursive formula for the rank of the N\'eron-Severi groups of these fiber powers. For fiber squares, we construct unconditionally a set of independent elements in the N\'eron-Severi groups. When $E --> C$ is the universal elliptic curve over the modular curve $X_0(M)/\Q$, we apply the Selberg trace formula to verify our recursive formula in the case of fiber squares. This gives an analytic proof of Tate's conjecture for such fiber squares over $\Q$, and it shows that the independent elements we constructed in fact form a basis of the N\'eron-Severi groups. This is the fiber square analog of the Shioda-Tate Theorem.
`Abstract' homomorphisms of l-adic Galois groups and Abelian varieties
Siman Wong
Mathematics , 2001,
Abstract: Let $k$ be a totally real field, and let $A/k$ be an absolutely irreducible, polarized Abelian variety of odd, prime dimension whose endomorphisms are all defined over $k$. Then the only strictly compatible families of abstract, absolutely irreducible representations of $\gal(\ov{k}/k)$ coming from $A$ are tensor products of Tate twists of symmetric powers of two-dimensional $\lambda$-adic representations plus field automorphisms. The main ingredients of the proofs are the work of Borel and Tits on the `abstract' homomorphisms of almost simple algebraic groups, plus the work of Shimura on the fields of moduli of Abelian varieties.
Fiber products of hyperelliptic curves
Siman Wong
Mathematics , 2003,
Abstract: Let $k$ be a number field, and let $S$ be a finite set of maximal ideals of the ring of integers of $k$. In his 1962 ICM address, Shafarevich asked if there are only finitely many $k$-isomorphism classes of algebraic curves of a fixed genus $g\ge 1$ with good reduction outside $S$. He verified this for $g=1$ by reducing the problem to Siegel's theorem. Parshin extended this argument to all hyperelliptic curves (cf. also the work of Oort). The general case was settled by Faltings' celebrated work. In this note we give a short proof of Shafarevich's conjecture for hyperelliptic curves, by reducing the problem to the case $g=1$ using the Theorem of de Franchis plus standard facts about discriminants of hyperelliptic equations.
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