177,654 research outputs found
Clustering of ions at atomic dimensions in quantum plasmas
No full textBy means of particle simulations of the equations of motion for ions interacting among themselves under the influence of newly discovered Shukla–Eliasson attractive force (SEAF) in a dense quantum plasma, we demonstrate that the SEAF can bring ions closer at atomic dimensions. We present simulation results of the dynamics of an ensemble of ions in the presence of the SEAF without and with confining external potentials and collisions between ions and degenerate electrons. Our particle simulations reveal that under the SEAF, ions attract each other, come closer, and form ionic clusters in the bath of degenerate electrons that shield ions. Furthermore, an external confining potential produces robust ion clusters that can have cigar- and ball-like shapes, which remain stable when the confining potential is removed. The stability of ion clusters is discussed. Our results may have applications to solid density plasmas (density exceeding 1023 per cm3), where the electrons will be degenerate and quantum forces due to the electron recoil effect caused by the overlapping of electron wave functions and electron tunneling through the Bohm potential, electron-exchange and electron-exchange and electron correlations associated with electron-1/2 spin effect, and the quantum statistical pressure of the degenerate electrons play a decisive role
"To Tell a Story is to Affirm Life". Death and Storytelling in Vikram Chandra's "Red Earth and Pouring Rain"
No full textIn Vikram Chandra’s first published work, "Red Earth and Pouring Rain", characters and situations are defined by the stories told, and "All stories have in them the seed of all other stories; any story, if continued long enough, becomes other stories". In other words, the narration does not aspire to recounting the reality of things as they are but to constructing "a finely coloured dream, a thing of passion and joy, a huge lie that will entertain and instruct and enlighten [...] the Big Indian Lie". The orality of traditional narrative drawn upon by the author is recreated on paper through a series of imaginative licences that have more in common with South American magical realism than the classic models of the middle-class Anglo-Saxon novel. Starting from these assumptions, this essays aims ai demonstrating that, although the novel breaks with the space-time continuum and with normal narrative cause-and-effect mechanisms in a way shared with postmodern narrative, the way in which this conception of time, History, and stories is used leads to a reconstruction and redefinition of a reality observed from a new viewpoint, which has very little to do with the postmodern rhetoric of terminality. It recalls, rather, an openness towards the unknown, a readiness to accept change and the fantastic, and a community-based element that are characteristics of traditional narration
Effect of Topographic Data Accuracy on Water Storage Environmental Service and Associated Hydrological Attributes in South Florida
No full textThe effects of digital elevation model (DEM) accuracy on terrain attributes and water storage were evaluated by comparing a standard 10-m U. S. Geological Survey DEM and a 10-m DEM derived from Light Detection and Ranging (LIDAR) data, on a ranchland that participated in a water storage environmental services program in South Florida. Elevation differences between the two DEMs ranged from -0.73 m to 1.6 m with a low (31%) correlation. Frequency analysis showed that 64% of the grids in the study area had elevation differences of 0.8 m or greater. Spatial distribution of wetlands and ditches were better represented by the LIDAR than the USGS DEM. Surface water storage in the study area and an isolated wetland was 49% and 21% more, respectively, for the USGS DEM than LIDAR DEM in wet seasons. In dry seasons, the LIDAR DEM resulted in 28% higher storage than the USGS DEM. Annually, the USGS DEM resulted in an average 44% more storage than LIDAR DEM. For a major rainstorm in 2008, the USGS showed 92% inundation of the study area and 44% for the LIDAR DEM. In a selected wetland, the USGS DEM resulted in an average 23% higher annual water storage than LIDAR DEM. In two sub-watersheds in the study area, USGS DEM resulted in an average 40% more pasture inundation than LIDAR DEM. Results indicate the importance of topographic data accuracy in quantified water storage and design of water control structures in water storage environmental services programs. DOI: 10.1061/(ASCE)IR.1943-4774.0000430. (C) 2012 American Society of Civil Engineers
Tau, β-amyloid and β-amyloid precursor protein distribution in the entorhinal-hippocampal alvear and perforant pathways in the Alzheimer's brain
No full textIt has been suggested that the pathological lesions of Alzheimer's disease (AD) spread along neuronal connections. This study was designed to examine this hypothesis in the alvear and perforant pathways, two well-defined neuroanatomical pathways that project from the entorhinal cortex to the hippocampus. Paraffin-sections of hippocampal-entorhinal cortex from 25 AD cases were immunolabelled for tau, β-amyloid (Aβ) and β-amyloid precursor protein (βAPP). We used image-analysis to quantify immunolabelling at both ends of the alvear and perforant pathways. At the beginning and the end of the alvear pathway, area of immunolabelling in µm2 per area of field (72000 µm2) were as follows: tau 349 and 821 (P<0.01), Aβ 349 and 61 (P<0.05) and βAPP 18 and 73 (P<0.01). Corresponding values for the perforant pathway were tau 421 and 387, Aβ382 and 115 (P<0.05) and βAPP 55 and 83. Tau was significantly greater at the end than at the beginning of the alvear pathway, but similar at both ends of the perforant pathway. There was significantly more Aβ at the beginning than at the end of the alvear and perforant pathway. These results at least in part reinforce previous work [19] that tau-rich areas may be neuronally connected to Aβ-rich areas
RNAi of <i>nhx-2</i> impedes reproductive senescence and aging via restoring mitochondrial membrane depolarization in <i>C. elegans</i>
No full textNeurodegenerative diseases do not have a complete cure yet. The strategies that target overall healthy aging might be very effective in treating such debilitating conditions. Reproductive senescence (RS) is one such phenomenon which could be associated with healthy aging vis-à-vis neurodegeneration. Here, we have employed bioinformatics, functional genomics, and molecular biology approaches to understand the mechanistic association between RS and NDs. Employing RNAi induced silencing we performed a systematic screening of subset of 22 such genes that delay reproductive senescence; on the basis of their effect on the various endpoint of neurodegeneration including α-synuclein aggregation, ROS level, locomotion and effect of estradiol upon the functioning of these genes in transgenic strain NL5901 of C. elegans. Our studies led to the identification of a Na+/H+ exchanger as its silencing had a profound effect on endpoints associated with PD. Further, we performed an in silico analysis and found out that the estradiol receptor is having an affinity towards direct inverse repeats of upstream region of nhx-2. We treated worms with 17 beta-estradiol and it gave rise to the altered mRNA levels of nhx-2. We further observed that RNAi of nhx-2, prolonged reproductive span of the worms by 71.3%. Knockdown of nhx-2 is known to alter pH of the gut so we endeavored to decipher whether the observed effects are correlated with selective food absorption. Performing network analysis, immunoblotting and fecundity assay we found out that nhx-2 RNAi is actually working via SIR-2.1 and in absence of SIR-2.1 effects exerted via nhx-2 are withdrawn. When we performed a co knockdown of sir-2.1 and nhx-2, RNAi of nhx-2 did not alter the fecundity of C. elegans which proves that it is showing its effect via altering the levels and functionality of SIR-2.1. We observed that nhx-2 is actually giving rise to selective food absorption and that is mimicking calorie restriction which in turn altering the levels of SIR-2.1.In order to check the mechanistic insight we blindly performed a real-time analysis of genes associated with several pathways and we found that nhx-2 RNAi is affecting genes of the mitochondrial pathway. We also checked the mitochondrial membrane potential of individual cells of worm sine nhx-2 is a proton exchanger and we found that it also improves mitochondrial health by restoring the depolarization of mitochondrial membrane potential. Hence, knockdown of nhx-2, impedes reproductive senescence, extends healthy reproductive span and ameliorates effects associated with neurodegeneration.
The data here substantiates the link between reproductive senescence with aging and neuronal health via genes that can alter all over the reproductive health of C. elegans
Structural Rearrangement of the Serotonin Transporter Intracellular Gate Induced by Thr276 Phosphorylation
No full textMolecular dynamics trajectories for Structural Rearrangement of the Serotonin Transporter Intracellular Gate Induced by Thr276 Phosphorylation by Matthew C. Chan, Erik Procko, Diwakar Shukla
RNAi of <i>nhx-2</i> impedes reproductive senescence and aging via restoring mitochondrial membrane depolarization in <i>C. elegans</i>
No full textNeurodegenerative diseases do not have a complete cure yet. The strategies that target overall healthy aging might be very effective in treating such debilitating conditions. Reproductive senescence (RS) is one such phenomenon which could be associated with healthy aging vis-à-vis neurodegeneration. Here, we have employed bioinformatics, functional genomics, and molecular biology approaches to understand the mechanistic association between RS and NDs. Employing RNAi induced silencing we performed a systematic screening of subset of 22 such genes that delay reproductive senescence; on the basis of their effect on the various endpoint of neurodegeneration including α-synuclein aggregation, ROS level, locomotion and effect of estradiol upon the functioning of these genes in transgenic strain NL5901 of C. elegans. Our studies led to the identification of a Na+/H+ exchanger as its silencing had a profound effect on endpoints associated with PD. Further, we performed an in silico analysis and found out that the estradiol receptor is having an affinity towards direct inverse repeats of upstream region of nhx-2. We treated worms with 17 beta-estradiol and it gave rise to the altered mRNA levels of nhx-2. We further observed that RNAi of nhx-2, prolonged reproductive span of the worms by 71.3%. Knockdown of nhx-2 is known to alter pH of the gut so we endeavored to decipher whether the observed effects are correlated with selective food absorption. Performing network analysis, immunoblotting and fecundity assay we found out that nhx-2 RNAi is actually working via SIR-2.1 and in absence of SIR-2.1 effects exerted via nhx-2 are withdrawn. When we performed a co knockdown of sir-2.1 and nhx-2, RNAi of nhx-2 did not alter the fecundity of C. elegans which proves that it is showing its effect via altering the levels and functionality of SIR-2.1. We observed that nhx-2 is actually giving rise to selective food absorption and that is mimicking calorie restriction which in turn altering the levels of SIR-2.1.In order to check the mechanistic insight we blindly performed a real-time analysis of genes associated with several pathways and we found that nhx-2 RNAi is affecting genes of the mitochondrial pathway. We also checked the mitochondrial membrane potential of individual cells of worm sine nhx-2 is a proton exchanger and we found that it also improves mitochondrial health by restoring the depolarization of mitochondrial membrane potential. Hence, knockdown of nhx-2, impedes reproductive senescence, extends healthy reproductive span and ameliorates effects associated with neurodegeneration.
The data here substantiates the link between reproductive senescence with aging and neuronal health via genes that can alter all over the reproductive health of C. elegans
On K3-fibred LARGE Volume Scenario with de Sitter vacua from anti-D3-branes
No full textIn the context of type IIB superstring compactifications on K3-fibred (weak) Swiss-cheese Calabi Yau (CY) orientifolds, we consider the realisation of de Sitter vacua obtained through the introduction of an D3 ̄ -brane at the tip of a highly warped throat of Klebanov-Strassler type. Aiming to have a concrete global realisation, we perform a systematic search for the CY threefolds with 2 < h1,1< 5 arising from the Kreuzer-Skarke database, which satisfy the minimal requirements of being K3-fibred and suitable for moduli stabilisation within the LARGE Volume Scenario (LVS). In this context, after scanning the set of K3-fibred CY threefolds with a so-called diagonal del-Pezzo divisor needed for LVS, we realise that one of the main challenging requirements for having D3 ̄ -brane uplifting is to find a suitable orientifold involution which can simultaneously result in a sufficient large D3 tadpole charge along with the presence of suitable O3-planes. In our detailed analysis (limited to) using the CY threefolds with small h1,1, we observe that these topological requirements rule out most of the CY geometries leading to only few possibly suitable candidates for the purpose of D3 ̄ -brane uplifting. Subsequently, we present a global model using one such explicit K3-fibred CY threefold with h1,1 = 4 in which all the moduli can be consistently stabilised in a de Sitter minimum of the scalar potential
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
Chaetocnema (Udorpes) rahlensis Shukla 1960
No full text78. Chaetocnema (Udorpes) rahlensis Shukla, 1960 Chaetocnema rahlensis Shukla, 1960: 77. TL: India: Rahla, Upper Beas Vally. TD: Zoological Survey of India, Calcutta, India (type lost). Distribution: India. Host plants: Unknown. Description (after Shukla, 1960): Body length 2.4 mm, width 1.2 mm. Body ovate, strongly convex; light bronze-colored, with cupreous reflections. labrum dark brown; first two antennal segments shiny light brown. Femora shiny bronze-colored; tibiae and tarsi lighter brown. Head with the labrum strongly transverse, very much broader than long, angulated at the sides, anteriorly narrowed, anterior margin straight, laterally ridged; clypeus anteriorly deeply and triangularly emarginated; just behind anterior margin strongly and deeply punctate, setose; frontal tubercles and interantennal carina absent; from the middle of the interocular space two oblique, deep narrow grooves extend up to orbital border and bounded by an acute carina along the length of groove near the middle of the interocular space; vertex with fine and sparse punctures unlike the strongly punctate interocular space in front. Eyes entire. Pronotum nearly as wide as long; the sides gently rounded, narrowing anteriorly, strongly convex; lateral margins invisible when viewed from above; rather sparsely punctate; the punctures as large as on the vertex; under higher mangification a smooth impunctate narrow longitudinal line along the middle of the disc; interstices highly granular, without depression on the disc. Scutellum short; very broad; apex acute; impunctate. Elytral base as wide as pronotum; callus distinct but intrahumeral groove absent; very slightly depressed longitudinally behind the scutellum along the suture; punctate striate in eleven distinct rows, including a short scutellar and an extreme marginal row; the rows tend to form pairs; in the depression behind the scutellum along the suture; the punctures irregular due to the presence of a few extra punctures in addition to those of the scutellar row; interstices granular, at the sides a few of them costate; punctures similar to the apex. Wings absent. Underside with the gena rugosely punctate and pubescent; flanks of the pronotum with a few punctures at anterior and posterior margins; otherwise smooth and shiny; prosternum rugosely punctate; the meso- and metasterna punctate but not so deeply and closely. Remarks: The type deposited in the Zoological Survey of India, Kolkata is lost. This species is extremely close to C. alticola, which is also apterous. However, in C. rahlensis, the pronotum is sparsely and weakly punctate, while in C. alticola, it is closely and strongly punctate. Based on the original description, this species may be differentiated from other Oriental species by the following combination of characters: 1) frons with strong and closely placed punctures, while vertex and pronotum are rather sparsely and weakly punctate; 2) wingless, base of elytra as wide as that of pronotum; 3) pronotum nearly as wide as long, strongly convex, lateral margins invisible from above and with a longitudinal impunctate area in the middle of disc.Published as part of Ruan, Yongying, Yang, Xingke, Konstantinov, Alexander S., Prathapan, Kaniyarikkal D. & Zhang, Mengna, 2019, Revision of the Oriental Chaetocnema species (Coleoptera, Chrysomelidae, Galerucinae, Alticini), pp. 1-206 in Zootaxa 4699 (1) on page 186, DOI: 10.11646/zootaxa.4699.1.1, http://zenodo.org/record/354303
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