145 research outputs found

    A Perturbative Approach to the Tunneling Phenomena

    Full text link
    The double-well potential is a good example, where we can compute the splitting in the bound state energy of the system due to the tunneling effect with various methods, namely WKB or instanton calculations. All these methods are non-perturbative and there is a common belief that it is difficult to find the splitting in the energy due to the barrier penetration from a perturbative analysis. However, we will illustrate by explicit examples containing singular potentials (e.g., Dirac delta potentials supported by points and curves and their relativistic extensions)that it is possible to find the splitting in the bound state energies by developing some kind of perturbation method.Comment: 24 pages, 4 figure

    Solitonic solutions and particle localization in higher dimensional spaces

    Get PDF
    Thesis (Master)--Izmir Institute of Technology, Physics, Izmir, 2003Includes bibliographical references (leaves: 82-87)Text in English; Abstract: Turkish and Englishvii, 87 leavesFirst the basic extra dimensional theory (i.e. Kaluza-Klein theory) and the main aspects of solitons are reviewed. Then the current status of extra dimen-sional models and the application of solitons (especially kinks) in this context are studied. The extra dimensional models for fermion localization are considered with a particular emphasis. Finally a variation of these models which tries to in-corporate the best aspects of various models for fermion localization is presented

    Nondegeneracy of the Ground State for Nonrelativistic Lee Model

    Get PDF
    In the present work, we first briefly sketch construction of the nonrelativistic Lee model on Riemannian manifolds, introduced in our previous works. In this approach, the renormalized resolvent of the system is expressed in terms of a well-defined operator, called the principal operator, so as to obtain a finite formulation. Then, we show that the ground state of the nonrelativistic Lee model on a compact Riemannian manifolds is nondegenerate using the explicit expression of the principal operator that we obtained. This is achieved by combining heat kernel methods with positivity improving semi-group approach and then applying these tools directly to the principal operator, rather than the Hamiltonian, without using cut-offs.Comment: 16 pages, typos are corrected, abstract and some sentences in the text are improved. Appears in Journal of Mathematical Physics, volume 55, issue 8 (2014

    A robust nonlinear scale space change detection approach for SAR images

    Get PDF
    In this paper, we propose a change detection approach based on nonlinear scale space analysis of change images for robust detection of various changes incurred by natural phenomena and/or human activities in Synthetic Aperture Radar (SAR) images using Maximally Stable Extremal Regions (MSERs). To achieve this, a variant of the log-ratio image of multitemporal images is calculated which is followed by Feature Preserving Despeckling (FPD) to generate nonlinear scale space images exhibiting different trade-offs in terms of speckle reduction and shape detail preservation. MSERs of each scale space image are found and then combined through a decision level fusion strategy, namely "selective scale fusion" (SSF), where contrast and boundary curvature of each MSER are considered. The performance of the proposed method is evaluated using real multitemporal high resolution TerraSAR-X images and synthetically generated multitemporal images composed of shapes with several orientations, sizes, and backscatter amplitude levels representing a variety of possible signatures of change. One of the main outcomes of this approach is that different objects having different sizes and levels of contrast with their surroundings appear as stable regions at different scale space images thus the fusion of results from scale space images yields a good overall performance

    POHJOIS-KYMEN SAIRAALAN YHTEISPÄIVYSTYKSEN SUURKÄYTTÄJÄANALYYSI

    Get PDF
    Opinnäytetyön tavoitteena oli Kouvolan kaupungin Pohjois-Kymen sairaalan suurkäyttäjäasiakkaiden tunnistaminen ja heidän saamaansa sosiaalisen tuen analysointi vuoden 2014 ajalta. Osatavoitteena oli myös palveluiden kehittämistarpeiden havainnointi. Opinnäytetyön tulokset toimivat laajemman Pohjois-Kymen sairaalan toteuttaman yhteispäivystyksen ja terveysasemien suurkäyttäjäanalyysin osa- ja taustatutkimuksena. Opinnäytetyön tutkimusmenetelmä oli pääosin kvantitatiivinen sisältäen kvalitatiivisia osioita. Tutkimusaineisto kerättiin kesällä 2015 tiedonkeruulomakkeen avulla Kouvolan kaupungin Terveys- sekä SosiaaliEffican asiakaskirjausmerkinnöistä. Havaintoyksiköitä oli 238, joista 229 analysoitiin. Suurkäyttäjäksi määrittyi henkilö, joka oli käyttänyt yhteispäivystyksen palveluita yli 10 kertaa vuoden 2014 aikana. Tutkimusaineisto tallennettiin SPSS-ohjelmaan, aineiston tilastolliset analyysit suoritettiin SPSS- sekä Excel-ohjelmilla. Opinnäytetyön määrällinen aineisto analysoitiin ristiintaulukoinnein. Laadullisen aineiston analyysimenetelminä olivat dokumentti- sekä sisällönanalyysi. Tutkimuksen tulokset esitettiin prosentteina, keskiarvoina, sanallisesti sekä havainnollistettiin kuvin ja taulukoin. Yleisimmiksi suurkäyttäjäryhmiksi profiloituvat pitkäaikais- ja monisairaat sekä mielenterveysongelmaiset asiakkaat. Yhteispäivystyksen suurkäyttäjäasiakkaiden sosiaaliset ja terveydelliset taustat ovat moninaiset. Asiakasasiakirjoissa sosiaalisen tuen kuvaus on niukkaa. Pääosin sosiaalista tukea saadaan puolisolta ja lähisukulaisilta, mutta runsaasti myös julkiselta sektorilta. Valtaosa yhteispäivystyksen suurkäyttäjäasiakkaista käyttää runsaasti myös muita julkisia terveyspalveluita. Vajaa kolmasosa ei käytä muita julkisen sektorin palveluita, kuin terveydenhoitopalveluita. Sosiaalitoimen asiakkuus on yli kolmanneksella suurkäyttäjistä. Suurkäyttäjäasiakkaiden tarvitsema tuki on monialaista, yksilöllistä ja pitkäkestoista. Tehostettua tukea tarvitsevat asiakkaat olisi syytä tunnistaa sosiaali- ja terveydenhuollon peruspalveluissa ja palvelut tulisi toteuttaa moniammatillisen tiimin tiiviinä yhteistyönä, sosiaali- ja terveydenhuollon palveluohjaajaparein.The objective of this thesis was to recognize the frequent clients of North Kymi Hospital in Kouvola, and to analyze the amount of social support that was received by them in the year 2014. A part objective was to also observe the need for improving the services. The results of the thesis work as part and background research for a broader frequent client analysis done by North Kymi Hospital for the joined emergency services and health centre users. The research method for the thesis was mainly quantitative, including qualitative parts. The research material was gathered in the summer of 2015 with the help of an information form from Kouvola City Health and Social Effica patient logs. There were 238 analyzing units, of which 229 were analyzed. A person that had used the services of the joined emergency service over ten times within the year 2014, was considered as a frequent client. The research material was saved on to a SPSS-programme, the statistical analyze of the material was done with SPSS and Excel programmes. The quantitative material of the thesis was analyzed with cross charts. The qualitative material analyzing methods were document and content analysis. The results of the research were presented in percentages, averages, verbally and also demonstrated by pictures and charts. The most common frequent client groups were profiled as people with long-term and many illnesses, and also patients with mental health issues. The frequent clients´ social and health backgrounds are varied. In the patient documents the description for social support is scarce. Social support is mainly received from spouses and close relatives, but also a lot from the public sector. A majority of the frequent clients of the joined emergency service also use plenty of other public health services. Less than a third do not use other services from the public sector except for health care services. Over a third of the frequent clients are customers of social services. The support that the frequent clients need is varied, individual and long-term. Clients that need enhanced support should be recognized in the basic services of social and health care, services should be carried out in close co-operation with a multi professional team, with social and health care service counsellor pairs

    Automatic and semi-automatic extraction of curvilinear features from SAR images

    Get PDF
    Extraction of curvilinear features from synthetic aperture radar (SAR) images is important for automatic recognition of various targets, such as fences, surrounding the buildings. The bright pixels which constitute curvilinear features in SAR images are usually disrupted and also degraded by high amount of speckle noise which makes extraction of such curvilinear features very difficult. In this paper an approach for the extraction of curvilinear features from SAR images is presented. The proposed approach is based on searching the curvilinear features as an optimum unidirectional path crossing over the vertices of the features determined after a despeckling operation. The proposed method can be used in a semi-automatic mode if the user supplies the starting vertex or in an automatic mode otherwise. In the semi-automatic mode, the proposed method produces reasonably accurate real-time solutions for SAR images

    Plant growth promoting bacteria enhances photosynthesis, nodulation and root system architecture in lentil under lead toxicity

    Get PDF
    The usage of plant growth-promoting bacteria (PGPB) in mitigation of harmful effects of lead (Pb) toxicity in plants and bioremediation of it from soils is a sustainable, effective and low-cost strategy. The experiment was laid out to investigate the role of PGPB on morphological and physiological growth, root system architecture and nodulation of lentil under Pb stress. The experiment was conducted according to completely randomized factorial design with four replications at the laboratory of the Field Crops Department, Siirt University, Siirt in 2022. The four Pb levels and three bacterial inoculations were used in the experiment. Plant height, seedling fresh weight, root fresh weight, seedling dry weight, root dry weight, total chlorophyll content, taproot length, number of lateral roots, total root length and number of nodule varied between 15.7-25.9 cm, 0.123-0.235 g, 0.019-0.092 g, 0.0104-0.0326 g, 0.0076-0.0146 g, 27.9-47.2%, 8.9-19.2 cm, 4.00-14.67, 17.6-44.8 cm and 1.37 10.63, respectively. Bio-priming with PGPB containing 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity increased dry matter accumulation up to 56.1% and 22.9% in shoots and roots, respectively. Chlorophyll content enhanced up to 17.9% compared with control application. Besides, root system architecture and nodule formation were improved by bio priming both under stress and non-stress conditions. Bio-priming with PGPB may be a sustainable solution to mitigate oxidative stress and promote plant growth and yield in lentil under Pb-contaminated soils
    corecore