1,717 research outputs found

    Fission-fusion dynamics and group-size dependent composition in heterogeneous populations

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    Many animal groups are heterogeneous and may even consist of individuals of different species, called mixed-species flocks. Mathematical and computational models of collective animal movement behaviour, however, typically assume that groups and populations consist of identical individuals. In this paper, using the mathematical framework of the coagulation-fragmentation process, we develop and analyse a model of merge and split group dynamics, also called fission-fusion dynamics, for heterogeneous populations that contain two types (or species) of individuals. We assume that more heterogeneous groups experience higher split rates than homogeneous groups, forming two daughter groups whose compositions are drawn uniformly from all possible partitions. We analytically derive a master equation for group size and compositions and find mean-field steady-state solutions. We predict that there is a critical group size below which groups are more likely to be homogeneous and contain the abundant type/species. Despite the propensity of heterogeneous groups to split at higher rates, we find that groups are more likely to be heterogeneous but only above the critical group size. Monte-Carlo simulation of the model show excellent agreement with these analytical model results. Thus, our model makes a testable prediction that composition of flocks are group-size dependent and do not merely reflect the population level heterogeneity. We discuss the implications of our results to empirical studies on flocking systems.Comment: 19 pages, 8 figure

    Studies on high power ultrasonic microembossing and organic light emitting diodes (OLEDs) for the creation of lab-on-CD devices for sensor related applications

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    This study demonstrates the application of High Power Ultrasonic Microembossing Technology (HPUMT) in producing microfeatures on polymer substrates. The work reviews a novel method of obtaining flash free and precise microfeatures by manipulating the material density through microcellular foaming. The microfeatures created on the polymer substrates were further characterized by analyzing the feature depth with respect to the critical ultrasonic embossing operating parameters such as embossing heating times (s), embossing amplitude (ym) at a constant embossing trigger force (N). An experiment design was constructed and performed to characterize the parameters on foamed and unfoamed (or regular) versions of polystyrene (PS) and polypropylene (PP) sample materials. Results indicated feature depth was proportional to heating times, amplitude and force. It was also seen the maximum depth was achieved in the shortest cycle times with higher amplitudes and forces of operation. HPUMT was further studied to create functional network of microchannels functioned as reservoirs, reaction chamber and burst or gate valves to form a centrifugal biosensing platform that is also referred to as a lab-on-CD or a bio-CD device. The surface energy of the polymer substrates was increased to enable fluid flow by using a surfactant based organic coating to facilitate hydrophilicity. Using an organic light emitting diode (OLEDs) as an electroluminescence source provided luminescence decay results in good agreement with stern-volmer relationship. The functionality of the OLED-coupled lab-on-CD device was further tested in measuring unknown concentrations of a particular analyte in corn slurry sample which contained numerous contaminants. Combinatorial multianalyte sensing was also made possible on a single bio-CD using a four photodetector (PD) quad preamp disk sensor

    Rhabdomyosarcoma-Report of Two Cases and Review

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    Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children. It is seen rarely in adults. There are three variants of RMS which include  embryonal, alveolar which are commonly seen in children and pleomorphic type seen in adult. In recent years, spindle cell and sclerosing variants of RMS have also been recognized in adults. Because of the scarcity of data  further  extensive research has to be carried regarding the tumor. The prognosis  of the tumor is worse in adults when compared to children, with an overall 5-year survival of less than 30%. This review will discuss the clinicopathological characteristics of RMS, the different histological variants, and two case reports of our Institution.   &nbsp

    MHD Flow past a Semi-Infinite Vertical Plate with Mass Transfer

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    An analysis is performed to study the MHD flow of an electrically conducting, incompressible, viscous fluid past a semi-infinite vertical plate with mass transfer, under the action of transversely applied magnetic field is carried out. The heat due to viscous dissipation and the induced magnetic field are assumed to be negligible. The dimensionless governing equations are unsteady, two-dimensional, coupled and non-linear partial differential equations. A most accurate, unconditionally stable and fast converging implicit finite difference scheme is used to solve the non-dimensional governing equations. The effects of external cooling (Gr > 0) of the plate by the free convection are studied

    Experimental Investigation on the Effect of Multi-Winglets

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    An extensive experimental study is conducted to examine the potentiality of Multi-Winglets (similar to bird tip feathers) for the reduction of Induced Drag, improved CL without increase in span of aircraft wing. The model composed of a rectangular wing built from NACA 0015 airfoil constituted of three winglets, which are small wings without sweep & twist. The test conducted in subsonic wind tunnel at flow speed 20m/s and placing the wing at angle of attack ranging from -5 to +15 deg. And also the wing with no winglet (bare wing) and with single winglet also tested in the same condition as in the case of three winglets (multi-winglet). Wind tunnel balances provided lift measurements and tuft flow visualization obtained wingtip vortex information. The results show that multi-winglet system reduced induced drag by 27.9% and improved CL by 26.5% compare to bare wing

    Speech Emotion Recognition System

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    Speech Emotion Recognition (SER) is a research topic which has a wide range of applications. The features of speech such as, Mel Frequency cepstrum coefficients (MFCC ) are extracted which are uttered in the speech. To classify different emotional states such as boredom, happiness, sadness, neutral, anger, from various emotional sound tracks from a database containing emotional speech SVM is used as classifier. SVM is used for classification of emotions. The accuracy obtained in SVM is very much higher. DOI: 10.17762/ijritcc2321-8169.15057

    DESIGN AND EVALUATION OF SELF-NANOEMULSIFYING DRUG DELIVERY SYSTEMS OF MANIDIPINE FOR ENHANCEMENT OF SOLUBILITY

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    Objective: The present work is aimed at developing liquid self-nanoemulsifying drug delivery system (liquid-SNEDDS) of manidipine. Methods: The manidipine SNEDDS is formulated with excipients comprising Capmul MCM as oil phase, Transcutol P as surfactant, and Lutrol L 300 as cosurfactant. The prepared fifteen formulations of manidipine SNEDDS were performed for emulsification time, percentage transmittance, particle size, drug release, in vitro dissolution and stability studies. Ternary phase diagram plotted using Chemix software. Results: The optimized manidipine liquid SNEDDS formulation (F14) subjected to drug-excipient compatibility studies by Fourier-transform infrared spectroscopy and characterized for particle size, zeta potential, scanning electron microscopy, and stability studies. The morphology of manidipine SNEDDS indicates spherical shape with uniform particle distribution. The percentage drug release from optimized formulation F14 (98.24±5.14%) was higher than that of pure drug (39.17±2.98%). The stability data indicated no noticeable change in drug content, emulsifying properties, drug release, and appearance. Conclusion: Hence, a potential SNEDDS formulation of manidipine developed with enhanced solubility, dissolution rate, and bioavailability
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