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Search Results: 1 - 10 of 330183 matches for " Roy S. Feldman "
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Sour Ageusia in Two Individuals Implicates Ion Channels of the ASIC and PKD Families in Human Sour Taste Perception at the Anterior Tongue
Taufiqul Huque, Beverly J. Cowart, Luba Dankulich-Nagrudny, Edmund A. Pribitkin, Douglas L. Bayley, Andrew I. Spielman, Roy S. Feldman, Scott A. Mackler, Joseph G. Brand
PLOS ONE , 2009, DOI: 10.1371/journal.pone.0007347
Abstract: Background The perception of sour taste in humans is incompletely understood at the receptor cell level. We report here on two patients with an acquired sour ageusia. Each patient was unresponsive to sour stimuli, but both showed normal responses to bitter, sweet, and salty stimuli. Methods and Findings Lingual fungiform papillae, containing taste cells, were obtained by biopsy from the two patients, and from three sour-normal individuals, and analyzed by RT-PCR. The following transcripts were undetectable in the patients, even after 50 cycles of amplification, but readily detectable in the sour-normal subjects: acid sensing ion channels (ASICs) 1a, 1β, 2a, 2b, and 3; and polycystic kidney disease (PKD) channels PKD1L3 and PKD2L1. Patients and sour-normals expressed the taste-related phospholipase C-β2, the δ-subunit of epithelial sodium channel (ENaC) and the bitter receptor T2R14, as well as β-actin. Genomic analysis of one patient, using buccal tissue, did not show absence of the genes for ASIC1a and PKD2L1. Immunohistochemistry of fungiform papillae from sour-normal subjects revealed labeling of taste bud cells by antibodies to ASICs 1a and 1β, PKD2L1, phospholipase C-β2, and δ-ENaC. An antibody to PKD1L3 labeled tissue outside taste bud cells. Conclusions These data suggest a role for ASICs and PKDs in human sour perception. This is the first report of sour ageusia in humans, and the very existence of such individuals (“natural knockouts”) suggests a cell lineage for sour that is independent of the other taste modalities.
Comparing Apples and Oranges: Query Tradeoff in Submodular Maximization
Niv Buchbinder,Moran Feldman,Roy Schwartz
Computer Science , 2014,
Abstract: Fast algorithms for submodular maximization problems have a vast potential use in applicative settings, such as machine learning, social networks, and economics. Though fast algorithms were known for some special cases, only recently Badanidiyuru and Vondr\'{a}k (2014) were the first to explicitly look for such algorithms in the general case of maximizing a monotone submodular function subject to a matroid independence constraint. The algorithm of Badanidiyuru and Vondr\'{a}k matches the best possible approximation guarantee, while trying to reduce the number of value oracle queries the algorithm performs. Our main result is a new algorithm for this general case which establishes a surprising tradeoff between two seemingly unrelated quantities: the number of value oracle queries and the number of matroid independence queries performed by the algorithm. Specifically, one can decrease the former by increasing the latter and vice versa, while maintaining the best possible approximation guarantee. Such a tradeoff is very useful since various applications might incur significantly different costs in querying the value and matroid independence oracles. Furthermore, in case the rank of the matroid is $O(n^c)$, where $n$ is the size of the ground set and $c$ is an absolute constant smaller than $1$, the total number of oracle queries our algorithm uses can be made to have a smaller magnitude compared to that needed by Badanidiyuru and Vondr\'{a}k. We also provide even faster algorithms for the well studied special cases of a cardinality constraint and a partition matroid independence constraint, both of which capture many real-world applications and have been widely studied both theorically and in practice.
Online Submodular Maximization with Preemption
Niv Buchbinder,Moran Feldman,Roy Schwartz
Computer Science , 2015,
Abstract: Submodular function maximization has been studied extensively in recent years under various constraints and models. The problem plays a major role in various disciplines. We study a natural online variant of this problem in which elements arrive one-by-one and the algorithm has to maintain a solution obeying certain constraints at all times. Upon arrival of an element, the algorithm has to decide whether to accept the element into its solution and may preempt previously chosen elements. The goal is to maximize a submodular function over the set of elements in the solution. We study two special cases of this general problem and derive upper and lower bounds on the competitive ratio. Specifically, we design a $1/e$-competitive algorithm for the unconstrained case in which the algorithm may hold any subset of the elements, and constant competitive ratio algorithms for the case where the algorithm may hold at most $k$ elements in its solution.
Sérgio Alberto Feldman
Revista de História Regional , 2007,
Abstract: This article investigates the subject of the progressist Jews in Curitiba, Brazil. The research makes the connection between Jews and communism in the beginning of the 20th century. It observes the national and the cultural factors in the formation of this group. The Communist Party in Russia didnt accept this way. The Zionist and the others Jewish groups disagreed with the progressist Jews. In Curitiba, they were ejected from the Jewish community and start a short period of autonomy. Their ssociation called SOCIB and the history of this progressist group were very productive in the cultural sense. They had theater group and s Choral of Jewish music. They tried to conserve the Jewish culture and the Idish (dialect of the oriental Europe Jews). They had political positions very similar to the communist but tried to be autonomous and never affiliated in the party. There was others progressist groups in Brazil and also in Latin America and they had an international association called IKUF. Esse artigo investiga a quest o dos judeus progressistas em Curitiba, Brasil. A pesquisa faz a conex o entre judeus e o comunismo no início do século XX. Examina os fatores nacionais e culturais na forma o deste grupo. O Partido Comunista na Rússia n o aceitava esta proposta. Os Sionistas e outros agrupamentos judaicos discordavam da posi o e das idéias dos judeus progressistas. Em Curitiba eles foram excluídos da comunidade judaica e iniciaram um breve período de autonomia nos anos 50. Sua associa o denominava-se SOCIB e a história desse grupo progressista foi muito produtiva no aspecto cultural. Eles tinham um grupo teatral e um Coral de música judaica. Eles tentaram conservar a cultura judaica e o Idish (dialeto dos judeus da Europa Oriental). Tinham posi es políticas emelhantes aos comunistas, mas mantiveram-se aut nomos e nunca se afiliaram ao partido. Havia outros agrupamentos progressistas no Brasil e também na América Latina e todos eram filiados a uma associa o internacional denominada IKUF.
Algorithmic Methods for Sponsored Search Advertising
Jon Feldman,S. Muthukrishnan
Computer Science , 2008,
Abstract: Modern commercial Internet search engines display advertisements along side the search results in response to user queries. Such sponsored search relies on market mechanisms to elicit prices for these advertisements, making use of an auction among advertisers who bid in order to have their ads shown for specific keywords. We present an overview of the current systems for such auctions and also describe the underlying game-theoretic aspects. The game involves three parties--advertisers, the search engine, and search users--and we present example research directions that emphasize the role of each. The algorithms for bidding and pricing in these games use techniques from three mathematical areas: mechanism design, optimization, and statistical estimation. Finally, we present some challenges in sponsored search advertising.
Model of the Effects of Improving TB Diagnosis on Infection Dynamics in Differing Demographic and HIV-Prevalence Scenarios  [PDF]
Allison S. Rhines, Midori Kato-Maeda, Marcus W. Feldman
Journal of Tuberculosis Research (JTR) , 2015, DOI: 10.4236/jtr.2015.31001
Abstract: This paper seeks to examine the sensitivity of tuberculosis transmission (TB) dynamics to the rate at which infectious individuals with active TB begin a TB treatment course, and therefore cease to be infectious to others. We model this by varying both the rate at which individuals are diagnosed and begin treatment, and the demographic conditions in which the epidemic occurs. An agestructured deterministic ordinary differential equation model is used to study the sensitivity of TB transmission dynamics to the implementation of a more effective diagnostic such as Xpert MTB/ RIF in a high HIV prevalence setting. Sensitivity analysis of the effectiveness of the diagnostic (λ) shows the interim disease dynamics in three demographic scenarios defined by differences in HIV prevalence and age structure at a constant transmission rate. In the near future, we expect the diagnostic to have the most effect in areas of high HIV prevalence. In the long term, we expect the diagnostic to have the most significant impact at high transmission rates regardless of HIV prevalence and age structure.
Therapeutic evaluation of Ivermectin Pour on against tick infestation in dogs
S. Roy and M. Roy
Veterinary World , 2010,
Abstract: Study was conducted on 20 dogs of different breeds and age, of Bhilai area naturally infested with Rhipicephalus Sanguineus ticks. Dogs with moderate to severe tick infestations were treated with ivermectin pour on @ 1ml/10kg body weight. In the present study ivermectin pour on was found to be 100 percent effective against naturally occurring tick infestation in dogs. [Vet. World 2010; 3(3.000): 113-114]
Convex-Cyclic Matrices, Convex-Polynomial Interpolation & Invariant Convex Sets
Nathan S. Feldman,Paul McGuire
Mathematics , 2015,
Abstract: We define a convex-polynomial to be one that is a convex combination of the monomials $\{1, z, z^2, \ldots\}$. This paper explores the intimate connection between peaking convex-polynomials, interpolating convex-polynomials, invariant convex sets, and the dynamics of matrices. In particular, we use these intertwined relations to both prove which matrices are convex-cyclic while at the same time proving that we can prescribe the values and a finite number of the derivatives of a convex-polynomial subject to certain natural constraints. These properties are also equivalent to determining those matrices whose invariant closed convex sets are all invariant subspaces. Our characterization of the convex-cyclic matrices gives a new and correct proof of a similar result by Rezaei that was stated and proven incorrectly.
Carbonic Anhydrase III S-Glutathionylation Is Necessary for Anti-Oxidant Activity  [PDF]
P. Roy, M. Ireland, S. Roy, J. Craft, C. Bartholomew
Yangtze Medicine (YM) , 2018, DOI: 10.4236/ym.2018.24026
Abstract: Carbonic anhydrase isozyme CA3 protects cells against oxidative stress. Ectopic expression of murine Ca3, but not Ca2, protects proto-oncogene Evi1 expressing Rat1 fibroblast cells (ca3low) against hydrogen peroxide (H2O2) induced stress. Ca3 is S-glutathionylated via glutathione adducts with cysteines 181 and 186. Substitution of both Ca3 cysteines with serine fails to protect cells from oxidative stress. Insertion of cysteine at 181 and 186 in Ca2 is insufficient for conferring efficient anti-oxidant activity. This shows for the first time that S-glutathionylation of cys181 and cys186 residues is required for Ca3 anti-oxidant activity but that additional factors are also required.
Effect of administration of tamoxifen citrate on xanthine oxidase activity of liver during 3-methylcholanthrene induced carcinogenesis in female albino mice
S Roy
Biology and Medicine , 2012,
Abstract: Tamoxifen citrate, the non-steroidal anti-estrogen and the first selective estrogen receptor modulator is the treatment of choice for patients with all stages of estrogen receptor positive breast cancer. Although Cytochrome P-450s (CYP) are well known to be responsible for much of its metabolism, fragmentary studies have been carried out to analyze the activity of xanthine oxidase, a non-CYP drug metabolizing enzyme, in tamoxifen metabolism. So, the present investigation is aimed to ascertain the effect of tablet and nano-formulation of tamoxifen on xanthine oxidase expression during 3-methylcholanthrene-induced carcinogenesis. It is found that oral administration of tamoxifen in both the formulations significantly (p < 0.01) decreases the xanthine oxidaseactivity in liver tissue of female mice. We speculate our results to be beneficial for the better understanding of drug metabolism and intensity, which in turn will pave the way for new and efficient nano-formulations of drug coming into therapeutic use.
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