194,306 research outputs found
Pseudoxytenanthera madhavii P. Tetali, Datar, S. Tetali, Muralidharan, and R. K. Choudhary 2021, sp. nov.
No full textPseudoxytenanthera madhavii P.Tetali, Datar, S.Tetali, Muralidharan, and R.K.Choudhary sp. nov. Shining culms, white powdery scuff covering young culms, fresh culm sheaths with waxy coating, black to brownish black hairs on culm sheaths, undulating blades; culm wall thickness of 0.9–1.9 cm at breast height, long apiculate anthers; striated, membranous lower palea, filament tube united more than half of its length, 2–3 stigmas and hirsute ovary. Type:— INDIA. Maharashtra: Pune district, Velhe Taluka, Shirkoli village, 18.360759° N, 73.613238° E, 687 AMSL, 02 October 2019 (fl.), P. Tetali, MN Datar and RK Choudhary, 000141 (holotype: AHMA!, isotypes BSI!, CAL!). A deciduous, arborescent and gregarious bamboo. Rhizomes sympodial, produce 1–3 tillers per rhizome. Culms erect, loose, 9–16 m high; the young ones without branches, covered with white powdery deciduous scurf; older culms (more than 3 years) turn yellowish green, hollow, diameter 6–10 cm, at breast height 8.5 cm; culm wall thickness 0.9–1.9 cm, solid at base, solidness maximum up to one meter, cavity 2.5–5 cm at breast height. Few branches appear in second year mostly on upper part, branches with slightly out curved tips, older branches drooping. Internodes terete, 22–70 cm long, lower ones shorter, middle nodes show maximum internodal distance. Nodes slightly swollen with prominent white hairy rings 10 mm above, and 2–5 mm below. Culm-sheaths: young ones covered with wax coating, narrowed upwards, sparsely covered with black or dark-brown deciduous hairs; 17–44 cm long and 14–28 cm wide; auricles with few long hairs; shoulders with or without hairs; deep prominent ligule; dentate or fimbriate; 5–7 mm high; culm sheath blade persistent, conspicuous, triangular; imperfect; prominently undulating, 7–15 cm long, gradually tapering, reflexed at maturity; sparsely hairy on abaxial surface. Leaves 7–9 per branch; base round; blade lanceolate to linear–lanceolate; acuminate; 16–28 cm long; veins 12–14; mid vein prominent; ligule purplish; base attenuated into a small petiole; petiole grooved; 0.3–0.7 cm long. Inflorescence of a large compound panicle with distinct globular heads; heads 2–5 cm in diameter, spinescent; spikelets 0.8–0.9 cm long; lower glume, ovate, 0.7–0.8 cm, mucronate, 5–8 nerved, lemmas ovate, upper lemma sharply pointed, 1.6–1.7 cm long; lower lemma ovate, sharply acute, 1.4– 1.5 cm long; upper palea mucronate, 1.2–1.3 cm long, sparsely hairy on back; lower palea dull green, two keeled, cleft at the top, hairy above, almost the same size; some floriferous branches show both male and female flowers, exerted anthers and plumose stigmas. Staminal tube up to 1.5 cm long; stamens exerted, anthers bright sulphur yellow, apiculate, 0.7–0.9 cm long, filaments united below to almost half of the length, free above; free part of filaments longer or almost equal to the size of anthers, light purple, turns colourless and drooping after dehiscence; gynoecium long, up to 1.2 cm; ovary and style hairy; stigma 2–3, dark purple, plumose. Local name:— Both names Mes and Manga are misapplied to Pseudoxytenanthera stocksii. However local communities of the northern Western Ghats distinguish them from each other based on morphological characters. The present description of Pseudoxytenanthera madhavii will clear the doubts in use of vernacular names. Pseudoxytenanthera madhavii, should be known by the name Mes while its allied species P. stocksii by the name Manga. Phenology:— Gregarious flowering of this species is neither recorded in last 25 years by authors during their field work, nor there is any report of the flowering from the northern Western Ghats. Careful observations were made for the present sporadic flowering. Insects visit flowers mostly in the morning and continue till afternoon; non dehisced anthers exist even at 2 pm. Honey bees and solitary bees are the most common opportunistic visitors interested in pollen collection. However, seed setting seems to be very poor. Etymology:— The specific epithet is given in honour of Prof. Madhav Gadgil, eminent Indian ecologist for his contribution in the field of Biodiversity and conservation in India and his affection towards bamboos. Habitat, distribution and utilities:— Pseudoxytenanthera madhavii is one of the most common bamboos of the northern Western Ghats. It is wild in moist and dry deciduous forests and has been widely cultivated in Pune and Satara districts of Maharashtra. Much of this bamboo is used in construction and in shelter construction. However, its demand for furniture and housing industry is increasing due to its smooth surface, mechanical strength, better slivering and stripe making qualities. In addition, it takes good polish.Published as part of Tetali, P., Tetali, Sujata, Muralidharan, E. M., Bokil, Sarang A., Choudhary, Ritesh Kumar & Datar, Mandar N., 2021, Pseudoxytenanthera madhavii (Poaceae: Bambusoideae), a new species of woody bamboo from the northern Western Ghats, India, pp. 186-196 in Phytotaxa 498 (3) on pages 187-194, DOI: 10.11646/phytotaxa.498.3.4, http://zenodo.org/record/542427
Cordiglottis longipedicellata (Orchidaceae), a new species from Vietnam
No full textCordiglottis longipedicellata Joongku Lee, T.B. Tran & R.K. Choudhary, a new species of Orchidaceae from Vietnam is described and illustrated. It is morphologically most similar to C. pulverulenta, but differs in its floral morphology and in having a longer pedicel. Colour photographs, a table comparing the floral structure of the new species with supposedly closely allied species and a key are provided to facilitate species identification. The present paper is also the first report of the genus Cordiglottis in the Indo-Chinese region.open
Pairwise Reachability Oracles and Preservers Under Failures
No full textIn this paper, we consider reachability oracles and reachability preservers for directed graphs/networks prone to edge/node failures. Let G = (V, E) be a directed graph on n-nodes, and P ⊆ V× V be a set of vertex pairs in G. We present the first non-trivial constructions of single and dual fault-tolerant pairwise reachability oracle with constant query time. Furthermore, we provide extremal bounds for sparse fault-tolerant reachability preservers, resilient to two or more failures. Prior to this work, such oracles and reachability preservers were widely studied for the special scenario of single-source and all-pairs settings. However, for the scenario of arbitrary pairs, no prior (non-trivial) results were known for dual (or more) failures, except those implied from the single-source setting. One of the main questions is whether it is possible to beat the O(n |P|) size bound (derived from the single-source setting) for reachability oracle and preserver for dual failures (or O(2^k n|P|) bound for k failures). We answer this question affirmatively. Below we summarize our contributions.
- For an n-vertex directed graph G = (V, E) and P ⊆ V× V, we present a construction of O(n √{|P|}) sized dual fault-tolerant pairwise reachability oracle with constant query time. We further provide a matching (up to the word size) lower bound of Ω(n √{|P|}) on the size (in bits) of the oracle for the dual fault setting, thereby proving that our oracle is (near-)optimal.
- Next, we provide a construction of O(n + min{|P|√ n,~n√{|P|}}) sized oracle with O(1) query time, resilient to single node/edge failure. In particular, for |P| bounded by O(√n) this yields an oracle of just O(n) size. We complement the upper bound with a lower bound of Ω(n^{2/3}|P|^{1/2}) (in bits), refuting the possibility of a linear-sized oracle for P of size ω(n^{2/3}).
- We also present a construction of O(n^{4/3} |P|^{1/3}) sized pairwise reachability preservers resilient to dual edge/vertex failures. Previously, such preservers were known to exist only under single failure and had O(n+min{|P|√n,~n√ {|P|}}) size [Chakraborty and Choudhary, ICALP'20]. We also show a lower bound of Ω(n √{|P|}) edges on the size of dual fault-tolerant reachability preservers, thereby providing a sharp gap between single and dual fault-tolerant reachability preservers for |P| = o(n).
- Finally, we provide a generic pairwise reachability preserver construction that provides a o(2^k n |P|) sized subgraph resilient to k failures, for any k ≥ 1. Before this work, we only knew of an O(2^k n |P|) bound implied from the single-source setting [Baswana, Choudhary, and Roditty, STOC'16]
A general skew-t mixed model that allows different degrees of freedom for random effects and error distributions
No full textAbstract not availablePankaj K. Choudhary, Dishari Sengupta, Phillip Casse
Toxicological profile for hexachlorobutadiene
No full textATSDR/TP-93/08Chemical manager(s)/author(s): Gangadhar Choudhary, Joyce M. Donohue, Yvonne N. Hales.Prepared by Life Systems, Inc., under subcontract to Clement International Corporation;prepared for U.S. Department of Health and Human Services, Public Health Service, Agency for Toxic Substances and Disease Registry under contract no. 205-88-0608.Includes bibliographical references (p. 105-128).205-88-060
Graphene q-switched Yb: phosphate glass channel waveguide laser
No full textQ-switched lasers can generate high-energy pulses that can have applications in medicine, material processing and defence. Waveguide lasers have several attractive features such as a low laser threshold and a high slope efficiency, provided that the propagation losses are kept low, compactness and mass-producibility. Ion-exchange is a simple and cheap technique to fabricate loss-loss waveguides in glass, with mode-locked operation being demonstrated in ion-exchanged Yb:phosphate glass lasers using a semiconductor saturable absorber mirror (SESAM). Using graphene as a saturable absorber has several key advantages over SESAMs such as a broad wavelength operating range, cost-effectiveness and ease of fabrication. Graphene has previously been used as a saturable absorber to demonstrate Q-switched mode-locking in a femtosecond-written glass waveguide laser and Q-switched operation in a carbon-irradiated Nd:YAG ceramic channel waveguide laser. In this paper we present an ion-exchanged Yb:phosphate glass waveguide laser, Q-switched using a graphene saturable absorber
PbSe quantum dots grown in a high-index low-melting-temperature glass for infrared laser applications
No full textPbSe quantum dots (QDs) were grown in high-refractive-index low-melting-temperature lead-phosphate glass. QDs with various sizes ranging from 2 nm to 5.3 nm were grown by controlling the growth parameters, heat-treatment temperature and time. The corresponding room-temperature exciton absorption was tuned within the infrared region from 0.93 µm to 2.75 µm. Photoluminescence was measured for samples with absorption peaks above 0.95eV. Real time quantum dot growth was demonstrated by monitoring the evolution of exciton absorption with temperature and time duration. As a demonstration of the use of QDs in laser applications, the saturation fluence (Fsat) of one of the QDs was evaluated and found to be ~2.1 µJ/cm2 at 1.2 µm
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Targets and small molecules against tauopathies : part 1: From genes to soluble, aggregation-prone tau proteins
No full textTau is a key dynamic regulator of microtubules in neurons. Tau-microtubule binding contributes to axonal stabilization in neurons. Its controlled-physiological weakening allows cell division and microtubule reorganization in fetal state or in mitotic neuronal cells. Tauopathies often show a decreased tau-microtubule binding and the aggregation of tau. The former leads to chronic microtubule-axonal destabilization, the latter preludes to the formation of intra-neuronal, insoluble tau deposits. Tau alternative splicing and post-translational modifications (hyper-phosphorylation, glycosylation, prolylamide bond isomerization, oxidation, etc.) are early events with an impact on tauopathies which may lead to disease-modifying therapeutic interventions. The most prospective therapeutic avenues targeted against these events are presented and critically discussed, selecting a single molecular target of particular relevance. Each target is presented together with its known small molecule modulators. Priority is given to mechanisms, targets and small molecules impacting on more than one tauopathycausing event
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