We consider shear-free radiating spherical stars in general relativity. In particular we study the junction condition relating the pressure to the heat flux at the boundary of the star. This is a nonlinear equation in the metric functions. We analyse the junction condition when the spacetime is conformally flat, and when the particles are travelling in geodesic motion. We transform the governing equation using the method of Lie analysis. The Lie symmetry generators that leave the equation invariant are identifed and we generate the optimal system in each case. Each element of the optimal system is used to reduce the partial differential equation to an ordinary differential equation which is further analysed. As a result, particular solutions to the junction condition are presented. These exact solutions can be presented in terms of elementary functions. Many of the solutions found are new and could be useful in the modelling process. Our analysis is the first comprehensive treatment of the boundary condition using a symmetry approach. We have shown that this approach is useful in generating new results. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2011.

The Lie theory of extended groups is a practical tool in the analysis of differential equations, particularly in the construction of solutions. A formalism of the Lie theory is given and contrasted with Noether's theorem which plays a prominent role in the analysis of differential equations derivable from a Lagrangian. The relationship between the Lie and Noether approach to differential equations is investigated. The standard separation of Lie point symmetries into Noetherian and nonNoetherian symmetries is shown to be irrelevant within the context of nonlocality. This also emphasises the role played by nonlocal symmetries in such an approach. / Thesis (M.Sc.)-University of Natal, Durban, 1997.

In this paper we report a low symmetry version of structure H hydrate that results from the hexagonal form on cooling below 167 K. Phase changes with temperature in the common clathrate hydrates structural families I, II and H have not been observed before, except in doped systems where ordering transitions take place or in the structure I hydrate of trimethylene oxide where the guest molecule dipoles are known to order. Since there is an inverse relationship between the effect of temperature and pressure on ices, it may well be that the low symmetry form reported at low temperature can also be reached by applying high pressure, and that in fact some of the observed high pressure phases are lower symmetry versions of hexagonal sH.

After amputation possibilities of human body motion are very limited. Amputation usually changes inert characteristics of human body parts and asymmetry of gait is visible. After prosthetics, gait with prosthesis remains asymmetric in relation with impaired body balance control. Loss of proprioreception in amputated side reduces regulation of stance. To retrieve stance skills and to train body balance pneumatic prosthesis is usually applied. The aim of this investigation was to assess influence of pneumatic prosthesis to stance and walking characteristics. To achieve this aim there were two main objectives 1) to evaluate influence of pneumatic prosthesis to stance symmetry in early period of prosthetics; 2) to evaluate influence of pneumatic prosthesis to gait symmetry in early period of prosthetics. Investigation was conducted using computerised pedobarograph „Parotec System“. Changes of weight center position were analyzed at the beginning and the end of rehabilitation period, time characteristics of weight bearing phases were assessed, vertical force and index of gait asymmetry were calculated. Investigation was performed at the department of Physical medicine and rehabilitation of Joint-stock company „Ortopedijos technika“. Patients who underwent below knee amputation were included. Testing was performed twice for every patient: at the beginning and the end of prosthetics. Weight center position in regard to both lower limbs was analyzed. At the end of prosthetics gait... [to full text]

A partly new train of thought has emerged during the last few years, which claims that national conditions are of importance for company strength in relation to international competitors. National competition has stood out as one of the most important explanatory factors, and is seen as the catalyst or motor in dynamic industrial environments. The demands and pressures that evolve from competition between geographically proximate companies stimulate the innovativeness within the industry. Thus, the question about why and how dynamics of competition develop and function has not been answered in existing research. The main purpose of this study is therefore to analyse the process of competition in industries with a high degree of geographical proximity between competitors, in order to improve the understanding of the character and dynamics of competition. A general review of literature dealing with competition at industry, strategic group, and organisation level was compiled. The review gave two dimensions by which four types of competition were possible to distinguish, degree of symmetry between competitores and degree of activity in competition. To obtain an understanding for the character and dynamics of competition, it is not enough to identify different types of competition. The process through which competition is formed over time also needs to be studied. Other theoretical approaches are therefore necessary. First, the companies' competitive actions should be understood from their experience and expectations of competition. Second, the specific competitive moves that are taken by individual companies are of importance for the competition. Third, competition has to be described as a process of interaction over time. A case-study approach has been used for the gathering of data. Case-studies have been conducted within three industries that differ from each other with regard to competition. Competition in the Frontloader industry has been driven by two companies equal in both size and relative strength. The competitors in the Lining industry are,on the other hand, dissimilar, both in respect to relative strength and to the orientation of their business. The third industry, that of Hoisters, is characterised by the domination by one company. Two major results have been reached in this study. First the concept climate of competition has been coined to analyse and describe the character of the four types of competition. The following four climates of competition emerge from the analysis; climate of rivalling competion, of co-existing competition, of evolutionary competition and climate of revolutionary competition. The climates of competition differ with regard to the functional and psychological distance between competitors, the possibility to survey competition, and the actors' acceptance of current rules-of-play and role distribution. The second result of the study is a greater understanding for the dynamics within competition. By analysing the character of and change in competition over time two partly different, but interwined forces, have been detected. Competition gives rise on the one hand to different kinds of learning processes, and on the other forces competitors to innovative and creative measures. / digitalisering@umu

The thesis is devoted to the application of a new class of probability metrics, N-distances, introduced by Klebanov (Klebanov, 2005; Zinger et al., 1989), to the problems of verification of the classical statistical hypotheses of goodness of fit, homogeneity, symmetry and independence. First of all a construction of statistics based on N metrics for testing mentioned hypotheses is proposed. Then the problem of determination of the critical region of the criteria is investigated. The main results of the thesis are connected with the asymptotic behavior of test statistics under the null and alternative hypotheses. In general case the limit null distribution of proposed in the thesis tests statistics is established in terms of the distribution of infinite quadratic form of random normal variables with coefficients dependent on eigenvalues and functions of a certain integral operator. It is proved that under the alternative hypothesis the test statistics are asymptotically normal. In case of parametric hypothesis of goodness of fit particular attention is devoted to normality and exponentiality criteria. For hypothesis of homogeneity a construction of multivariate distribution free two-sample test is proposed. Testing the hypothesis of uniformity on hypersphere in more detail S1 and S2 cases are investigated. In conclusion, a comparison of N-distance tests with some classical criteria is provided. For simple hypothesis of goodness of fit in univariate case as a measure for... [to full text] / Disertacinis darbas yra skirtas N-metrikų teorijos (Klebanov, 2005; Zinger et al., 1989) pritaikymui klasikinėms statistinėms suderinamumo, homogeniškumo, simetriškumo bei nepriklausomumo hipotezėms tikrinti. Darbo pradžioje pasiūlytas minėtų hipotezių testinių statistikų konstravimo būdas, naudojant N-metrikas. Toliau nagrinėjama problema susijusi su suformuotų kriterijų kritinės srities nustatymu. Pagrindiniai darbo rezultatai yra susiję su pasiūlytų kriterijaus statistikų asimptotiniu skirstiniu. Bendru atveju N-metrikos statistikų asimptotinis skirstinys esant nulinei hipotezei sutampa su Gauso atsitiktinių dydžių begalinės kvadratinės formos skirstiniu. Alternatyvos atveju testinių statistikų ribinis skirstinys yra normalusis. Sudėtinės suderinamumo hipotezės atveju išsamiau yra analizuojami normalumo ir ekponentiškumo kriterijai. Daugiamačiu atveju pasiūlyta konstrukcija, nepriklausanti nuo skirstinio homogeniškumo testo. Tikrinant tolygumo hipersferoje hipotezę detaliau yra nagrinėjami apskritimo ir sferos atvejai. Darbo pabaigoje lyginami pasiūlytos N-metrikos bei kai kurie klasikiniai kriterijai. Neparametrinės suderinamumo hipotezės vienamačiu atveju, kaip palyginimo priemonė, nagrinėjamas Bahaduro asimptotinis santykinis efektyvumas (Bahadur, 1960; Nikitin, 1995). Kartu su teoriniais rezultatais pasiūlytų N-metrikos tipo testų galingumas ištirtas, naudojant Monte-Karlo metodą. Be paprastos ir sudėtinės suderinamumo hipotezių yra analizuojami homogeniškumo testai... [toliau žr. visą tekstą]

Disertacinis darbas yra skirtas N-metrikų teorijos (Klebanov, 2005; Zinger et al., 1989) pritaikymui klasikinėms statistinėms suderinamumo, homogeniškumo, simetriškumo bei nepriklausomumo hipotezėms tikrinti. Darbo pradžioje pasiūlytas minėtų hipotezių testinių statistikų konstravimo būdas, naudojant N-metrikas. Toliau nagrinėjama problema susijusi su suformuotų kriterijų kritinės srities nustatymu. Pagrindiniai darbo rezultatai yra susiję su pasiūlytų kriterijaus statistikų asimptotiniu skirstiniu. Bendru atveju N-metrikos statistikų asimptotinis skirstinys esant nulinei hipotezei sutampa su Gauso atsitiktinių dydžių begalinės kvadratinės formos skirstiniu. Alternatyvos atveju testinių statistikų ribinis skirstinys yra normalusis. Sudėtinės suderinamumo hipotezės atveju išsamiau yra analizuojami normalumo ir ekponentiškumo kriterijai. Daugiamačiu atveju pasiūlyta konstrukcija, nepriklausanti nuo skirstinio homogeniškumo testo. Tikrinant tolygumo hipersferoje hipotezę detaliau yra nagrinėjami apskritimo ir sferos atvejai. Darbo pabaigoje lyginami pasiūlytos N-metrikos bei kai kurie klasikiniai kriterijai. Neparametrinės suderinamumo hipotezės vienamačiu atveju, kaip palyginimo priemonė, nagrinėjamas Bahaduro asimptotinis santykinis efektyvumas (Bahadur, 1960; Nikitin, 1995). Kartu su teoriniais rezultatais pasiūlytų N-metrikos tipo testų galingumas ištirtas, naudojant Monte-Karlo metodą. Be paprastos ir sudėtinės suderinamumo hipotezių yra analizuojami homogeniškumo testai... [toliau žr. visą tekstą] / The thesis is devoted to the application of a new class of probability metrics, N-distances, introduced by Klebanov (Klebanov, 2005; Zinger et al., 1989), to the problems of verification of the classical statistical hypotheses of goodness of fit, homogeneity, symmetry and independence. First of all a construction of statistics based on N-metrics for testing mentioned hypotheses is proposed. Then the problem of determination of the critical region of the criteria is investigated. The main results of the thesis are connected with the asymptotic behavior of test statistics under the null and alternative hypotheses. In general case the limit null distribution of proposed in the thesis tests statistics is established in terms of the distribution of infinite quadratic form of random normal variables with coefficients dependent on eigenvalues and functions of a certain integral operator. It is proved that under the alternative hypothesis the test statistics are asymptotically normal. In case of parametric hypothesis of goodness of fit particular attention is devoted to normality and exponentiality criteria. For hypothesis of homogeneity a construction of multivariate distribution-free two-sample test is proposed. Testing the hypothesis of uniformity on hypersphere in more detail S1 and S2 cases are investigated. In conclusion, a comparison of N-distance tests with some classical criteria is provided. For simple hypothesis of goodness of fit in univariate case as a measure for... [to full text]

Hypothesis. It is considered that during horseback riding the three-dimensional movements initiated by horse’s hind legs also cause responsive movements by the horseman; these movements stimulate symmetric muscle activeness and develop gross motor functions. Analogical movements that imitate three-dimensional actions caused by the horse performed on a therapeutic ball should have lesser influence on the symmetry of muscle activeness of children with CP since the actions are triggered by subjects themselves. It is likely that during gross motor function development the psycho-emotional condition of the human being should improve also perfecting the person’s horseback riding skills. The Aims of the Research. 1. To analyze horseback riding influence on gross motor function, muscle activeness and psycho-emotional condition of healthy children and children with CP. 2. To analyze the influence of exercises on a therapeutic ball on the symmetry of muscle activeness of healthy children and children with CP. The Goals of the Research. 1. To determine and to compare the symmetry of muscle (m. erector spinae lumbar, m. gluteus medius) activeness of healthy children and children with CP while doing exercises on a therapeutic ball using the methods of electromyography and myotonometry. 2. To evaluate the influence of horseback riding on gross motor function of beginner and advanced horsemen with CP. 3. To compare the muscle activeness symmetry of beginner and advanced horsemen (both... [to full text] / Darbo tikslai: ištirti jojimo poveikį sveikų raitelių ir raitelių, sergančių CP, bendrajai motorikai, raumenų aktyvumo simetriškumui ir psichoemocinei būsenai; ištirti pratimu ant didžiojo kamuolio poveikį sveikų vaikų ir vaikų, sergančių CP, raumenų aktyvumo simetriškumui. Tyrimo metodai: bendrosios motorikos funkcijų vertinimas; raumenų pasyviųjų mechaninių savybių tyrimas (miotonometrija); raumenų elektrinio aktyvumo tyrimas (elektromiografija); psichoemocinės būsenos ir jojimo įgūdžių stebėjimas. Tyrimo imtis. Atlikti keturi tyrimai, kuriuose dalyvavo 71 tiriamasis. Buvo tiriami sveiki, t.y. padėties ir judesio sutrikimų neturintys asmenys (n=19), ir asmenys, kuriems diagnozuotas cerebrinis paralyžius (n=52). Darbo naujumas ir mokslinė, praktinė reikšmė. Disertacinis darbas prisideda prie reikalingo, tolesnio kryptingo reabilitacijos metodų veiksmingumo vaikams, sergantiems cerebriniu paralyžiumi, tyrinėjimo Lietuvoje: atlikti tyrimai padėjo nustatyti skirtingų metodų veiksmingumą vaikams, sergantiems cerebriniu paralyžiumi. Tai pirmasis tyrimas, nagrinėjantis sveikų vaikų ir vaikų, sergančių CP, nugaros tiesiamojo ir sėdmens viduriniojo raumenų aktyvumo simetriškumą ant skirtingų paviršių. Gauti rezultatai atskleidė, kad pratimus ant didžiojo kamuolio savo praktikoje sėkmingai gali taikyti reabilitacijos specialistai, siekiant sumažinti sveikų vaikų ir vaikų, sergančių CP, sėdmens viduriniojo raumens pasyviųjų mechaninių savybių asimetrija. Įvertintas pažengusiųjų ir... [toliau žr. visą tekstą]

<p>The high-throughput framework AFLOW that has been developed and used successfully over the last decade is improved to include fully-integrated software for crystallographic symmetry characterization. The standards used in the symmetry algorithms conform with the conventions and prescriptions given in the International Tables of Crystallography (ITC). A standard cell choice with standard origin is selected, and the space group, point group, Bravais lattice, crystal system, lattice system, and representative symmetry operations are determined. Following the conventions of the ITC, the Wyckoff sites are also determined and their labels and site symmetry are provided. The symmetry code makes no assumptions on the input cell orientation, origin, or reduction and has been integrated in the AFLOW high-throughput framework for materials discovery by adding to the existing code base and making use of existing classes and functions. The software is written in object-oriented C++ for flexibility and reuse. A performance analysis and examination of the algorithms scaling with cell size and symmetry is also reported.</p> / Dissertation

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