2,150 research outputs found

    New targets for resolution of airway remodeling in obstructive lung diseases.

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    Airway remodeling (AR) is a progressive pathological feature of the obstructive lung diseases, including asthma and chronic obstructive pulmonary disease (COPD). The pathology manifests itself in the form of significant, progressive, and (to date) seemingly irreversible changes to distinct respiratory structural compartments. Consequently, AR correlates with disease severity and the gradual decline in pulmonary function associated with asthma and COPD. Although current asthma/COPD drugs manage airway contraction and inflammation, none of these effectively prevent or reverse features of AR. In this review, we provide a brief overview of the features and putative mechanisms affecting AR. We further discuss recently proposed strategies with promise for deterring or treating AR

    Numerical simulations of bedrock valley evolution by meandering rivers with variable bank material

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    Bedrock river valleys are fundamental components of many landscapes, and their morphologies—from slot canyons with incised meanders to wide valleys with strath terraces—may record environmental history. Several formation mechanisms for particular valley types have been proposed that involve changes in climatic and tectonic forcing, but the uniqueness of valley evolution pathways and the long-term stability of valley morphology under constant forcing are unknown and are not predicted in existing numerical models for vertically incising rivers. Because rivers often migrate more rapidly through alluvium than through bedrock, we explore the hypothesis that the distribution of bank materials strongly influences river meandering kinematics and can explain the diversity of bedrock river valley morphology. Simulations using a numerical model of river meandering with vector-based bank-material tracking indicate that channel lateral erosion rate in sediment and bedrock, vertical erosion rate, and initial alluvial-belt width explain first-order differences in bedrock valley type; that bedrock-bound channels can evolve under steady forcing from alluvial states; and that weak bedrock and low vertical incision rates favor wide, shallow valleys, while resistant bedrock and high vertical incision rates favor narrow, deep valleys. During vertical incision, sustained planation of the valley floor is favored when bedrock boundaries restrict channel migration to a zone of thin sediment fill. The inherent unsteadiness of river meandering in space and time is enhanced by evolving spatial contrasts in bank strength between sediment and bedrock and can account for several valley features—including strath terraces and underfit valleys—commonly ascribed to external drivers

    A vector-based method for bank-material tracking in coupled models of meandering and landscape evolution

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    Sinuous channels commonly migrate laterally and interact with banks of different strengths—an interplay that links geomorphology and life and shapes diverse landscapes from the seafloor to planetary surfaces. To investigate feedbacks between meandering rivers and landscapes over geomorphic timescales, numerical models typically represent bank properties using grids; however, this approach produces results inherently dependent on grid resolution. Herein we assess existing techniques for tracking landscape and bank-strength evolution in numerical models of meandering channels and show that grid-based models implicitly include unintended thresholds for bank migration that can control simulated landscape evolution. Building on stratigraphic modeling techniques, we develop a vector-based method for land surface- and subsurface-material tracking that overcomes the resolution-dependence inherent in grid-based techniques by allowing high-fidelity representation of bank-material properties for curvilinear banks and low channel lateral migration rates. We illustrate four specific applications of the new technique: (1) the effect of resistant mud-rich deposits in abandoned meander cutoff loops on meander belt evolution; (2) the stratigraphic architecture of aggrading, alluvial meandering channels that interact with cohesive-bank and floodplain material; (3) the evolution of an incising, meandering river with mixed bedrock and alluvial banks within a confined bedrock valley; and (4) the effect of a bank-height dependent lateral-erosion rate for a meandering river in an aggrading floodplain. In all cases the vector-based approach overcomes numerical artifacts with the grid-based model. Because of its geometric flexibility, the vector-based material tracking approach provides new opportunities for exploring the coevolution of meandering rivers and surrounding landscapes over geologic timescales

    College Enquiry Chatbot Using A.L.I.C.E

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    Innbsp thisnbsp paper,nbsp anbsp proposalnbsp isnbsp carriednbsp onnbsp tonbsp explainnbsp thenbsp designnbsp ofnbsp anbsp chatnbsp bot specifically tailored as an application which is going to help new students to solvenbsp allnbsp thenbsp problemsnbsp theynbsp facenbsp andnbsp thenbsp questionsnbsp whichnbsp arisesnbsp innbsp their mind during and after the admission . In particular, the proposal investigates the implementation of ALICE chat bot system as an application named as college enquiry chat bot. A keywords-based human-computer dialog system makes it possible that the user could chat with the computer using a natural language, i.e. in English

    Combining Physical Simulators and Object-Based Networks for Control

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    Physics engines play an important role in robot planning and control; however, many real-world control problems involve complex contact dynamics that cannot be characterized analytically. Most physics engines therefore employ . approximations that lead to a loss in precision. In this paper, we propose a hybrid dynamics model, simulator-augmented interaction networks (SAIN), combining a physics engine with an object-based neural network for dynamics modeling. Compared with existing models that are purely analytical or purely data-driven, our hybrid model captures the dynamics of interacting objects in a more accurate and data-efficient manner.Experiments both in simulation and on a real robot suggest that it also leads to better performance when used in complex control tasks. Finally, we show that our model generalizes to novel environments with varying object shapes and materials.Comment: ICRA 2019; Project page: http://sain.csail.mit.ed

    Stack Contention-alleviated Precharge Keeper for Pseudo Domino Logic

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    The dynamic circuits are supposed to offer superior speed and low power dissipation over static CMOS circuits. The domino logic circuits are used for high system performance but suffer from the precharge pulse degradation. This article provides different design topologies on the domino circuits to overcome the charge sharing and charge leakage with reference to the power dissipation and delay. The precharge keeper circuit has been proposed such that the keeper transistors also work as the precharge transistors to realize multiple output function. The performance improvement of the circuit\u27s analysis have been done for adders and logic gates using HSPICE tool. The proposed keeper techniques reveal lower power dissipation and lesser delay over the standard keeper circuit with less transistor count for different process variation

    Antimoth finishing treatment for woollens using tannin containing natural dyes

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    Attempts have been made to develop natural dye based antimoth finishing process using natural dyes as an alternative of  chemical based process. Natural dyes obtained from different sources are used to dye the woollen fabric and then screened for antimoth efficacy. Woollen fabrics dyed with extract of silver oak leaves, wall nut husk and pomegranate rind have shown highest resistance to moth attack. The screened sources carrying antimoth property are then subjected to phytochemical analysis along with non-carrying natural dyes for analyzing their chemical constituents. The result reveals that the chemical constituent of natural dyes plays a crucial role in determining antimoth efficacy. The amount of tannin content present in the natural dyes can be taken as an indicator to determine the antimoth efficacy

    A variant of the Mukai pairing via deformation quantization

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    We give a new method to prove a formula computing a variant of Caldararu's Mukai pairing \cite{Cal1}. Our method is based on some important results in the area of deformation quantization. In particular, part of the work of Kashiwara and Schapira in \cite{KS} as well as an algebraic index theorem of Bressler, Nest and Tsygan in \cite{BNT},\cite{BNT1} and \cite{BNT2} are used. It is hoped that our method is useful for generalization to settings involving certain singular varieties.Comment: 8 pages. Comments and suggestions welcom

    Efficacy of natural dye from Gerardiana diversifolia on pashmina (Cashmere) shawls

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    The present investigation deals with studies on potentiality of a colour extract from Gerardiana diversifolia as a source of natural dye, and on identification of chemical constituents responsible for dyeing ability. The efficacy of the extracted dye(s) on pashmina (Cashmere) fabrics has been evaluated for colour strength and fastness properties. Phytochemical studies reveal that the quinone and tannin are major components contributing to dyeing properties. The extracted colorant from Gerardiana diversifolia has potential to dye pashmina fabric with brown and grey shades having excellent wash and good to very good light fastness properties

    Tissue distribution and antileishmanial activity of liposomised Amphotericin-B in Balb/c mice

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    Antileishmanial activity and organ distribution of the antifungal drug Amphotericin-B in free and liposomised form have been studied in Balb/c mice infected with Leishmania donovani. Results indicate that Amphotericin-B in the liposomised form is significantly more active than the free form. This increase in the activity is perhaps related to the reduced drug toxicity rather than the altered drug distribution at the site of infection
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