1,356,514 research outputs found
Scientific Endeavors of A.M. Mathai: An Appraisal on the Occasion of his Eightieth Birthday, 28 April 2015
No full textA.M. Mathai is Emeritus Professor of Mathematics and Statistics at McGill University, Canada. He is currently the Director of the Centre for Mathematical and Statistical Sciences India. His research contributions cover a wide spectrum of topics in mathematics, statistics, physics, astronomy, and biology. He is a Fellow of the Institute of Mathematical Statistics, National Academy of Sciences of India, and a member of the International Statistical Institute. He is a founder of the Canadian Journal of Statistics and the Statistical Society of Canada. He was instrumental in the implementation of the United Nations Basic Space Science Initiative (1991–2012). This paper highlights research results of A.M. Mathai in the period of time from 1962 to 2015. He published over 300 research papers and over 25 books
Approximating spectral invariants of Harper operators on graphs II
No full textWe study Harper operators and the closely related discrete magnetic Laplacians (DML) on a graph with a free action of a discrete group, as defined by Sunada. The spectral density function of the DML is defined using the von Neumann trace associated with the free action of a discrete group on a graph. The main result in this paper states that when the group is amenable, the spectral density function is equal to the integrated density of states of the DML that is defined using either Dirichlet or Neumann boundary conditions. This establishes the main conjecture in a paper by Mathai and Yates. The result is generalized to other self adjoint operators with finite propagation speed
Novel modulators of non-selective and selective autophagy
No full textPå samme måte som søppel dannes fra vårt daglige forbruk, produserer cellene i kroppen vår avfallsprodukter som transporteres til cellens resykleringsstasjon (lysosomet), hvor det brytes ned og gjenvinnes. Dette skjer via en prosess kalt autofagi, som involverer oppsamling av kargo/søppel i en vesikkel (et autofagosom) som smelter sammen med lysosomet. Autofagi oppreguleres ved stress, f.eks sult, men et basalt nivå av autofagi er viktig i alle celler for å beskytte mot sykdommer som kreft og nevrodegenerering.
Dannelsen av autofagosomer er vist å involvere en rekke proteinkomplekser og lipider, men de eksakte mekanismene involvert i regulering av autofagi er ikke kjent. I denne avhandlingen har Benan John Mathai og medarbeidere vist at proteinet HS1BP3 er en negativ regulator av autofagi. De fant at HS1BP3 inhiberer autofagi ved å hemme aktiviteten til det lipid-modifiserende enzymet PLD1, som igjen er viktig for å lage lipidet fosfatidsyre (PA) som er vist å være viktig for autofagi. Mathai fant at den regulatoriske rollen til HS1BP3 i autofagi er konservert i zebrafisk larver som uttrykker en fluoreserende markør for autofagi (LC3).
Selektiv nedbryting av spesialavfall (som dysfunksjonelle mitokondrier eller protein aggregater) ved autofagi krever spesielle autofagi-reseptorer (f.eks p62) som binder kargo. Benan John Mathai og medarbeidere har identifisert et «eat-me signal» på mitokondrier som gjenkjennes av slike autofagi reseptorer. Ved depolarisering av mitokondriene akkumulerer matriksproteinene NIPSNAP1 og NIPSNAP2 på overflaten av mitokondriene hvor de binder autofagireseptorer, som fører til nedbrytning av de ødelagte mitokondriene (mitofagi). NIPSNAP1/2-mediert mitofagi er avhengig av proteinene PINK1 og PARKIN, som begge er assosiert med Parkinsons sykdom. Mathai fant at zebrafisk larver som mangler Nipsnap1 har økt oksidativt stress, redusert nivå av dopaminerge nevroner og redusert bevegelse.
Dette doktorgradsarbeidet er et viktig bidrag til vår forståelse av de molekylære mekanismene involvert i regulering og dannelse av autofagosomer og gir innsikt i betydningen av disse prosessene i å hindre utvikling av sykdom
Phlegra prasanna Caleb, Mungkung & Mathai, 2015, sp. nov.
No full textPhlegra prasanna sp. nov. Caleb & Mathai (Figs. 47-56) Type material. Holotype: male, scrub jungle regions, Madras Christian College, Tamil Nadu, India (12°91′97.51″ N, 80°12′24.72″ E, 32m, 20 MAR 2014, coll. John Caleb T. D., NCBS-QA481). Paratypes: 1 male from same location (06 OCT 2014, coll. John Caleb T.D., NCBS-QA482) and 1 male, Kadapa, Andhra Pradesh, India (14°45′10.50″ N, 78°79′38.68″ E, 138 m, 14 JAN 2015, coll. Samson, NCBS-AL062). Etymology. Specific epithet is a noun in apposition, a patronym after the first author's mother, Udaya Prasanna. Diagnosis. Species can be differentiated from other Phlegra species by the dark coloration of the body covered by metallic dark green iridescent hairs (Figs. 47, 50). Palp with long embolus (Figs. 53, 55), RTA with two peaks separated by a V-shaped depression (Figs. 54, 56). Description of male. Total length 4.11; carapace 2.32 long, 1.57 wide; abdomen 1.79 long, 1.03 wide. Cephalothorax dark, eye region covered with forward projecting hairs, inconspicuous pair of white stripes on the dorsal surface, eye field darker (Figs. 48, 51). Three white transverse stripes traverse across the clypeus extending into the cheek region. Anterior eyes surrounded by white scales anteriorly (Fig. 49). Chelicerae blackish, thick transverse stripe of white hairs at the proximal region. Sternum oval, covered with pale hairs (Fig. 52). Legs dark, proximal half of tarsus brownish yellow on all legs (Figs. 48, 49). Abdomen narrow, dark with greenish, iridescent hairs (Fig. 50). Palp with dark cymbium, long, slender embolus (Figs. 53, 55), RTA with two peaks separated by a V-shaped depression (Figs. 54, 56). Distribution. Chennai, India. 1 mm.Published as part of Caleb, John T. D., Mungkung, Soriephy & Mathai, Manu Thomas, 2015, Four new species of jumping spider (Araneae: Salticidae: Aelurillinae) with the description of a new genus from South India, pp. 1-18 in Peckhamia 124 (1) on pages 11-12, DOI: 10.5281/zenodo.509297
Phanuelus Caleb, Mungkung & Mathai, 2015, gen. nov.
No full textPhanuelus gen. nov. Caleb & Mathai Type species. Phanuelus gladstone sp.nov. Etymology. The proposed name is for the late Dr. G. J. Phanuel (Professor, Dept. of Zoology, MCC) who worked extensively on the spiders of Madras in the early 1960s. His work has been of great significance for later workers. The name is masculine in gender. Diagnosis. Small spiders characterized by short, very high cephalothorax, high and reduced thoracic region; abdomen round, nearly spherical. Leg III distinctly longer. Two RTAs (compared to usually two RTAs, sometimes with one RTA in Aelurillus, and two peaks, separated by a V or U shaped slit in Phlegra). Differs from Langona Simon in lacking a bunch of stiff hairs projecting from the base near RTA. Differs from Stenaelurillus Simon due to the absence of an anterior tegular apophysis. Embolus longer and thinner than in Stenaelurillus. Epigynum highly sclerotized, convex surface, with copulatory openings postero-laterally (whereas these are antero-median in Aelurillus, or hidden in circular grooves in Phlegra). Description. Spiders with small body (3-4 mm), carapace short and very high, short longitudinal fovea in a rounded, pit-like shallow depression in the centre just behind PLE line midway (Figs. 26, 32). Carapace widest at beginning of posterior slope; posterior slope very steep. PME closer to PLE than ALE. Clypeus vertical, moderately high (Figs. 28, 36). Male chelicerae without any tooth. Leg III longer than leg IV (Figs. 27, 37). Abdomen small, rounded with pairs of white spots arranged in the median, lighter lateral regions seen on females (Figs. 26, 33). Male palp with enlarged bulbus, tegulum leathery, embolus thin, two RTA, one long and bent at tip which is inconspicuous, other conspicuous, short and thick (Figs. 38, 39). Epigynum highly sclerotized, copulatory openings laterally placed apart, with meandering copulatory ducts (Figs. 40, 43, 44). Affinities. Species show clear affinity to subfamily Aelurillinae in genital structures and general morphology.Published as part of Caleb, John T. D., Mungkung, Soriephy & Mathai, Manu Thomas, 2015, Four new species of jumping spider (Araneae: Salticidae: Aelurillinae) with the description of a new genus from South India, pp. 1-18 in Peckhamia 124 (1) on page 7, DOI: 10.5281/zenodo.509297
On Mathai–Haubold Past Entropy Measure
No full textIn this paper, Mathai–Haubold past entropy measure is proposed and its properties are studied. Also some generalized inequalities related to Mathai–Haubold entropy measure are discussed. A Kernel based non-parametric estimator for the proposed measure is provided when the underlying sample follows ρ-mixing dependence condition. The consistency property and asymptotic normality of the proposed estimator are established. A simulation study is conducted to assess the performance of the estimator. A data set is analyzed for illustrative purposes
A whittaker function of matrix argument
No full textAbstractWhittaker functions arise naturally in many topics in physical, biological, and social sciences, such as input-output situations in econometric problems, storage-consumption situations, growth-decay situations, when dealing with bilinear forms in random variables, and so on. An account of some of these is available in Mathai (1993). The matrix-variate analogue is considered in this article. A Whittaker function of matrix argument is defined, and several new results on this function are established in this paper, complementing the results given earlier by Mathai and Pederzoli (1996). Some of these generalize the corresponding results in the scalar variable case
Stenaelurillus metallicus Caleb & Mathai, 2016, sp. nov.
No full text<i>Stenaelurillus metallicus</i> sp. nov. <p>Figs 1–22</p> <p> <b>Type material: Holotype:</b> Male (NCBS-AR103) from Madras Christian College (12.917659°N, 80.122859°E, alt. 32 m), Chennai, Tamil Nadu, India, 21 June 2013, leg. John Caleb T.D. <b>Paratypes</b> (from same location): 1 male (NCBS- AR110), 21 June 2013; 1 male (NCBS-AR109), 18 July 2013; 1 male & 1 female (NCBS-AR104 & AR113), 5 September 2013; 1 female (NCBS-AR112), 11 November 2013; 1 male (NCBS-AR111), 21 April 2015, all leg. John Caleb T.D.; 4 males & 4 females (NCBS-AR105 to AR108 & AR114 to AR117), 30 January 2014, leg. Karthy.</p> <p> <b>Etymology.</b> The specific name, an adjective, refers to the shining spots with metallic sheen on the male abdomen.</p> <p> <b>Diagnosis.</b> The male differs from all known <i>Stenaelurillus</i> species by orangish abdomen, with a pair of dark spots (Fig. 1; usually darker abdomen with white spots in other species). The species seems to be closely related to <i>S. sarojinae</i> Caleb & Mathai, 2014 by the presence of a well-developed ventral femoral distal process in the male palp (Fig. 11), but differs in having a slightly bent, short and thick embolus, not accompanied by a terminal apophysis (compare Fig. 19 herein with fig. 80 in Caleb <i>et al.</i> 2015). The female resembles <i>S. sarojinae</i> in having a pair of white spots on the abdomen, but differs in having globular spermatheca (bean-shaped in <i>S. sarojinae</i>; compare Figs 18, 22 herein with fig. 30 in Caleb & Mathai 2014).</p> <p> <b>Description. Male</b> (holotype). Total length: 4.63; carapace: 2.37 long, 1.64 wide; abdomen: 2.26 long, 1.43 wide. Carapace dark, covered with reddish-brown hairs; a pair of thin longitudinal white stripes extending from behind the ALEs and ending at posterior slope. Posterior end of carapace blackish (Figs 1–2). AMEs surrounded by white orbital setae. Short white hairs clothe the facial region from above the anterior eyes to the clypeal region (Fig. 3). Broad patch of white hairs extend backwards on the lateral margins of the carapace. Outer edge of carapace lined by thin stripe of white hairs. Eye measurements: AME 0.36, ALE 0.21, PME 0.07, PLE 0.26, AME–AME 0.09; AME–ALE 0.12; PME–PME 1.22; PME–PLE 0.19. Sternum oval, darkly pigmented medially, yellowish along the margins (Fig. 8). Chelicerae unident (Fig. 9); labium and maxillae yellowish. Femur I with a black patch prolaterally (Fig. 3). Coxae of all legs with patch of dark pigmentation ventrally (Fig. 8). Leg measurements: I 3.99 (1.35, 0.82, 0.74, 0.58, 0.49); II 3.95 (1.37, 0.79, 0.72, 0.56, 0.51); III 5.87 (1.78, 0.84, 1.14, 1.32, 0.79); IV 5.71 (1.70, 0.80, 1.11, 1.32, 0.78). Leg spination: leg I: Fm d 0-1-1-5; Pt pr 0-1-0; Tb pr 1-1, v 1-1 -2ap; Mt pr 1-1, v 2-2 ap; leg II: Fm d 0-1-1-5, pr 0-1-0; Pt pr and rt 0-1-0; Tb pr 1- 1-1, rt 0-1-0, v 1-1 -2ap; Mt pr 1-1, rt 1-1, v 2 -0-2ap; leg III: Fm d 0-1-1-5, pr 0-1-0; Pt pr and rt 0-1-0; Tb d 1-2-2, pr 1- 1, rt 1-0-1, v 0-1-2ap; Mt d 1-2-1-2, pr 1-1, rt 1-1-1, v 0-0-2ap; leg IV: Fm d 0-1-1-4, pr 0-1-0; Pt pr and rt 0-1-0; Tb d 1- 2-2, pr 1-1, rt 1-1, v 1-2 ap; Mt d 2-2-2, pr 1-1, rt 1-0-1, v 0-1-2ap. Abdomen with dark orange hairs on the sides, paler mid-dorsally with whitish hairs making indistinct chevron shaped markings; a pair of large spots with metallic luster present on the dorsum; a pair of indistinct black spots present laterally further behind. Abdomen outlined laterally by a fringe of long white hairs; spinnerets moderately long, black (Figs 1, 7, 10). Palp covered with short pale yellowish hairs; embolus short, thick and slightly bent, not accompanied by anterior terminal apophysis; RTA single with a broad base tapering toward the tip, slightly curved (Figs 19–20).</p> <p> <b>Female</b> (paratype NCBS-AR112). Total length 4.85; carapace: 2.15 long, 1.68 wide; abdomen: 2.70 long, 2.01 wide. Eye measurements: AME 0.39, ALE 0.20, PME 0.07, PLE 0.22, AME–AME 0.06; AME–ALE 0.10; PME–PME 1.25; PME–PLE 0.19. Leg measurements: I 3.58 (1.30, 0.60, 0.61, 0.48, 0.59); II 3.65 (1.29, 0.65, 0.60, 0.54, 0.58); III 6.19 (1.97, 0.94, 1.29, 1.18, 0.81); IV 5.65 (1.67, 0.80, 1.17, 1.24, 0.77). Leg spination: leg I: Fm d 0-1-1-5; Pt pr 0-1-0; Tb pr 1-1, v 1-1 -2ap; Mt pr 0-2, v 2-1 ap; leg II: Fm d 0-1-1-5, pr 0-1-0; Pt pr 0-1-0; Tb, pr 1-1, v 1-1 -2; Mt d 1-2, pr 0-1, v 2- 1 ap; leg III: Fm d 0-1-1-5, pr 0-1-0; Pt pr and rt 0-1-0; Tb d 1-2-2, pr 1-1, rt 1-1, v 0-1-2ap; Mt d 1-1-2, pr 1-2, rt 1-1-2ap, v 0-1-2ap; leg IV: Fm d 0-1-1-4; Pt pr and rt 0-1-0; Tb d 1-2-2, pr 1-1, rt 1-1, v 1-2 ap; Mt d 2-1-2, pr 1-1, rt 1-1, v 0-1- 2ap. Coloration pattern as in male, but differs in the following: general body color dull reddish-brown (Figs 4, 12).</p> <p>Anterior eyes outlined by reddish-brown setae on the upper half and lower half with white orbital setae (Fig. 6). A pair of white spots present on the abdomen (Figs 4, 12). Epigyne placed on a poorly sclerotized plate; copulatory ducts short, leading to the lower chambers (Figs 15, 16, 21); spermathecae globular (Figs 17, 18, 22).</p> <p> <b>Distribution.</b> Known only from type locality.</p>Published as part of <i>Caleb, John T. D. & Mathai, Manu Thomas, 2016, A new jumping spider of the genus Stenaelurillus Simon, 1886 from India (Araneae: Salticidae: Aelurillina), pp. 185-188 in Zootaxa 4103 (2)</i> on pages 185-188, DOI: <a href="http://zenodo.org/record/256878">10.5281/zenodo.256878</a>
Statistical Modeling of the Seismic Moments via Mathai Distribution
No full textMathai’s pathway model is playing an increasingly prominent role in statistical distributions. As a generalization of a great variety of distributions, the pathway model allows the studying of several non-linear dynamics of complex systems. Here, we construct a model, called the Pareto–Mathai distribution, using the fact that the earthquakes’ magnitudes of full catalogues are well-modeled by a Mathai distribution. The Pareto–Mathai distribution is used to study artificially induced microseisms in the mining industry. The fitting of a distribution for entire range of magnitudes allow us to calculate the completeness magnitude ([Formula: see text]). Mathematical properties of the new distribution are studied. In addition, applying this model to data recorded at a Chilean mine, the magnitude [Formula: see text] is estimated for several mine sectors and also the entire mine
On a Generalized Entropy Measure Leading to the Pathway Model with a Preliminary Application to Solar Neutrino Data
No full textAn entropy for the scalar variable case, parallel to Havrda-Charvat entropy, was introduced by the first author, and the properties and its connection to Tsallis non-extensive statistical mechanics and the Mathai pathway model were examined by the authors in previous papers. In the current paper, we extend the entropy to cover the scalar case, multivariable case, and matrix variate case. Then, this measure is optimized under different types of restrictions, and a number of models in the multivariable case and matrix variable case are obtained. Connections of these models to problems in statistical and physical sciences are pointed out. An application of the simplest case of the pathway model to the interpretation of solar neutrino data by applying standard deviation analysis and diffusion entropy analysis is provided
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