18 research outputs found

    Geochemical characteristics of charnockite and high grade gneisses from Southern Peninsular Shield and their significance in crustal evolution

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    Presented here are the results of detailed investigations encompassing externsive structural mapping in the charnockite-high grade gneiss terrain of North Arcot district and the type area in Pallavaram in Tamil Nadu supported by petrography, mineral chemistry, major, minor and REE distribution patterns in various lithounits. This has helped in understanding the evolutionary history of the southern peninsular shield. A possible tectonic model is also suggested. The results of these studies are compared with similar rock types from parts of Andhra Pradesh, Kerala, Sri Lanka, Lapland and Nigeria which has brought about a well defined correlation in geochemical characteristics. The area investigated has an interbanded sequence of thick pile of charnockite and a supracrustal succession of shelf type sediments, layered igneous complex, basic and ultrabasic rocks involved in a complex structural, tectonic, igneous and metamorphic events

    Structural patterns in high grade terrain in parts of Tamil Nadu and Karnataka

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    Detailed geological mapping in parts of Tamil Nadu and Karnataka has brought out vast areas occupied by highly deformed charnockite and high grade gneisses. These areas, similar to high grade shield terrains in other parts of the world have the impress of extensive tectonic reworking multideformation and polymetamorphism and are closely associated with layered ultramafics, shelf type sediments and different igneous events. In North Arcot and Charmapuri districts of Tamil Nadu and Kollegal taluk in Mysore district in Karnataka, charnockite is intensely cofolded with a supracrustal succession of layered ultramafics, pyroxene granulite, pink granolites, magnetite quartzite and khondalites. These areas have undergone five phases of deformation, five generations of basic dyke activities, four phases of migmatisation and two periods of metallogeny. Geochronological data ranges from 2900 m.y. to 750 m.y. In working out the tectanostratigraphy of the above areas the basic dykes of different generations have served as major time markers. In addition, the persistent strike continuity of linear bands of pyroxene granulite, pink granolite and magnetite quartzite has been of great utility in using them as structural markers for bringing out the complex structural history in these areas

    Nonlinear Fourier Transform for Analysis of Coherent Structures in Dissipative Systems

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    Using the cubic Ginzburg-Landau equation as an example, we demonstrate how the inverse scattering transform can be applied to characterize coherent structures in dissipative nonlinear systems. Using this approach one can reduce the number of the effective degrees of freedom in the system when the dynamic is dominated by the coherent structures, even if they are embedded in the dispersive waves and demonstrate unstable behavior

    The laminar-turbulent transition in a fibre laser

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    Studying the transition from a linearly stable coherent laminar state to a highly disordered state of turbulence is conceptually and technically challenging, and of great interest because all pipe and channel flows are of that type. In optics, understanding how a system loses coherence, as spatial size or the strength of excitation increases, is a fundamental problem of practical importance. Here, we report our studies of a fibre laser that operates in both laminar and turbulent regimes. We show that the laminar phase is analogous to a one-dimensional coherent condensate and the onset of turbulence is due to the loss of spatial coherence. Our investigations suggest that the laminar-turbulent transition in the laser is due to condensate destruction by clustering dark and grey solitons. This finding could prove valuable for the design of coherent optical devices as well as systems operating far from thermodynamic equilibrium

    Real-time observation of dissipative soliton formation in nonlinear polarization rotation mode-locked fibre lasers

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    Formation of coherent structures and patterns from unstable uniform state or noise is a fundamental physical phenomenon that occurs in various areas of science ranging from biology to astrophysics. Understanding of the underlying mechanisms of such processes can both improve our general interdisciplinary knowledge about complex nonlinear systems and lead to new practical engineering techniques. Modern optics with its high precision measurements offers excellent test-beds for studying complex nonlinear dynamics, though capturing transient rapid formation of optical solitons is technically challenging. Here we unveil the build-up of dissipative soliton in mode-locked fibre lasers using dispersive Fourier transform to measure spectral dynamics and employing autocorrelation analysis to investigate temporal evolution. Numerical simulations corroborate experimental observations, and indicate an underlying universality in the pulse formation. Statistical analysis identifies correlations and dependencies during the build-up phase. Our study may open up possibilities for real-time observation of various nonlinear structures in photonic systems

    Patient influence in home-based reablement for older persons: qualitative research

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    Abstract Background Reablement services are rehabilitation for older people living at home, being person-centered in information, mapping and the goal-setting conversation. The purpose of this study was to gain knowledge about conversation processes and patient influence in formulating the patients’ goals. There are two research questions: How do conversation theme, structure and processes appear in interactions aiming to decide goals of home-based reablement rehabilitation for the elderly? How professionals’ communication skills do influence on patients' participation in conversation about everyday life and goals of home-based reablement? Methods A qualitative field study explored eight cases of naturally occurring conversations between patients and healthcare professionals in a rehabilitation team. Patients were aged 67–90 years old. The reablement team consisted of an occupational therapist, physiotherapist, nurse and care workers. Data was collected by audio recording the conversations. Transcribed text was analyzed for conversational theme and communication patterns as they emerged within main themes. Results Patient participation differed with various professional leadership and communication in the information, mapping and goalsetting process. In the data material in its entirety, conversations consisted mainly of three parts where each part dealt with one of the three main topics. The first part was “Introduction to the program.” The main part of the talk was about mapping (“Varying patient participation when discussing everyday life”), while the last part was about goal setting (“Goals of rehabilitation”). Conclusions Home-based reablement requires communication skills to encourage user participation, and mapping of resources and needs, leading to the formulation of objectives. Professional health workers must master integrating two intentions: goal-oriented and person-centered communication that requires communication skills and leadership ability in communication, promoting patient influence and goal-setting. Quality of such conversations is complex, and requires the ability to apply integrated knowledge, skills and attitudes appropriate to communication situations

    Evaluation of the implementation of the Back Skills Training (BeST) programme using online training: a cohort implementation study

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    Objectives 1) Evaluate implementation of the Back Skills Training (BeST) programme, a group cognitive behavioural approach for patients with low back pain (LBP) developed for a clinical trial, into the National Health Service (NHS) in the United Kingdom; 2) Compare patient outcomes with the BeST Trial results. Design Two stage observational cohort implementation study. Participants Stage 1: NHS Clinicians enrolled in BeST online training. Stage 2: Patients with LBP attending NHS physiotherapy departments and enrolled in the BeST programme. Intervention An online training and implementation programme. Outcomes Stage 1: LBP attitudes and beliefs, self-rated competence, intention and actual implementation were collected before, immediately, 4- and 12-months post-training. Stage 2: Patients rated pain, function, recovery and satisfaction before and up to one year after attending the BeST programme. Results Stage 1: 1324 clinicians (157 NHS Trusts) enrolled in the training; 586 (44%) clinicians (101 NHS Trusts) completed training; 443/586 (76%) clinicians provided post-training data; 253/443 (57%) clinicians intended to implement the programme; 148/381 (39%) clinicians (54 NHS Trusts) provided follow-up data; 49/148 (33.1%) clinicians (27 NHS Trusts) implemented the programme. Attitudes and beliefs shifted towards a biopsychosocial model post-training. Stage 2: 923 patients were enrolled. Patients reported improvements in function (mean change: 1.55; 95%CI: 1.25, 1.86) and pain (−0.84; −1.1, −0.58) at follow-up. The majority rated themselves improved and satisfied with the programme. Conclusion Online training had good reach into NHS Trusts although, not everyone went onto implement the programme. Improvements in function that were consistent with the original trial were demonstrated
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