Žmogaus akių judesiai yra plačiai tyrinėjami ir taikomi praktikoje. Jie yra labai informatyvūs, todėl jais domisi įvairių sričių mokslininkai. Atskiri akių judesių parametrai yra tyrinėjimo objektai daugelyje mokslo sričių. Vienur akių judesiai patys yra tyrimo objektas, kituose yra tiriamas akių judesių vaidmuo regėjimo procese ir dar kituose akių judesių analizė naudojama sudėtingesnių žmogaus veiklos formų tyrime. Tokių sudėtingų uždavinių sprendimas neįmanomas be atitinkamų algoritmų sudarymo ir jų kompiuterinio modeliavimo. Darbo tikslas – sukurti programinę įrangą žmogaus akių sukties judesių modeliavimui ir rezultatų pateikimui. Darbe pateikiami žmogaus akių judesių tipai, jų matematinio aprašymo, registravimo ir pateikimo būdai. Taip pat aprašomas akies sukties judesių matavimo elektromagnetiniu metodu matematinis modelis. Siekiant geresnių rezultatų kuriant programinę įrangą, atliktas tyrimas nustatymui, kokie programavimo įrankiai plačiausiai taikomi akių judesių analizei. Pateikiami modeliavimo sistemos projektavimo etapai, keliami funkciniai reikalavimai, reikalavimai duomenims, sistemos išvaizdai, panaudojimui, pritaikymui. Aprašoma modeliavimo eiga ir sistemos testavimo rezultatai. Nurodomi sukurtos sistemos trūkumai ir keliai tolimesniam vystymui. Galutinis darbo rezultatas – sukurta programinė įranga akių sukties judesiams, įrašytiems elektromagnetiniu būdu, modeliuoti ir paruošti pradinius duomenis tolimesnei analizei. / Human eye movements are widely studied and applied in practice. They are very informative, and therefore they are interested in various fields of scientists. Individual parameters of the eye movements of research facilities in many scientific fields. Some eye movements are themselves the subject of the investigation, the other is studied eye movements of the role of vision and the other motion analysis using more sophisticated forms of human activity study. Such complex tasks can not be processed without the appropriate algorithms and their computer simulation. The aim - to create the software of human torsion eye movements modeling and presentation of results. The work presents the types of human eye movements, their mathematical description, recording and presentation techniques. It also describes the torsion eye movements measuring with electromagnetic method mathematical model. In order to better results in software development, a survey of the most widely applied tools of programming eye movements analysis. The design stages of simulation system, the functional requirements, data requirements, system appearance, recovery, adaptation are described. Describes the modeling process and system test results. Refer to the shortcomings of created system and ways for further development. Final result - designed software to the torsion eye movements recorded electromagnetically modeling, and preparation of baseline data for further analysis.

Ovarian torsion is a rare children’s acute abdominal disease which is difficult to diagnose and there is no consensus among scientists how to treat it. This is the first scientific research in Lithuania which analyses causes, optimal diagnostic criteria, the strategy, methods of surgical treatment and follow-up results of ovarian torsion in children. This is the largest research of the follow-up results of the conservative surgical treatment in the world. It was identified during the research that as many as 54.7% of the causes of ovarian torsion were congenital anatomical. In the case of 45.3% of the patients ovarian torsion was caused by pathological derivatives. In patients before menarche there were statistically significantly more mature teratomas (p=0.03). No specific symptoms of ovarian torsion in children were identified. Prior to the surgery, ultrasonography showed that the twisted ovary was on average 21.48 (17.06) times larger than the healthy ovary. Leukocytosis and ovarian blood flow disorders were statistically significantly more common in the case of ovarectomy. None of the girls who underwent detorsion with the ovary left in the abdominal cavity had thromboembolism or peritonitis; no malignant tumour was detected in any girl. According to the histopathological findings, no necrosis was detected in 14 (82.35%) removed ovaries, therefore they could be salvaged. Normal ovarian anatomy and folliculogenesis were retained in 95.24% of girls and women who were... [to full text] / Kiaušidžių užsisukimas – reta ūminė vaikų pilvo organų liga, kurios diagnostika sudėtinga, o dėl gydymo mokslininkai vis dar nesutaria. Tai pirmasis Lietuvoje mokslinis tyrimas, analizuojantis vaikų kiaušidžių užsisukimo priežastis, optimalius diagnostikos kriterijus, chirurginio gydymo taktiką ir metodus bei atokiuosius rezultatus. Šis atokiųjų konservatyvaus chirurginio gydymo rezultatų tyrimas yra didžiausias pasaulyje. Darbe nustatyta, kad 54,7 % kiaušidės užsisukimo priežasčių buvo įgimtos anatominės; 45,3 % ligonių kiaušidė užsisuko dėl patologinių darinių. Ligonėms iki menarchės statistiškai patikimai dažniau rasta brandžių teratomų (p=0,03). Specifinių vaikų kiaušidės užsisukimo simptomų ir požymių nenustatyta. Iki operacijos, tiriant echoskopu, užsisukusi kiaušidė buvo didesnė nei sveikoji vidutiniškai 21,48 (17,06) karto. Leukocitozė ir kiaušidės kraujotakos sutrikimai statistiškai patikimai dažnesni mergaitėms, kurioms kiaušidė pašalinta. Nė vienai mergaitei, kuriai kiaušidė buvo atsukta ir palikta pilvo ertmėje, nebuvo trombembolijos ir peritonito, nė vienai nerasta piktybinio naviko. Remiantis patologijos histologijos tyrimais, nustatyta, kad 14-oje (82,35 %) pašalintų kiaušidžių nekrozės ir patologinių darinių nebuvo, todėl jos galėjo būti išsaugotos. Patikrintų 95,24 % mergaičių ir moterų atsuktos kiaušidės anatomija ir folikulogenezė išliko normali.

Kiaušidžių užsisukimas – reta ūminė vaikų pilvo organų liga, kurios diagnostika sudėtinga, o dėl gydymo mokslininkai vis dar nesutaria. Tai pirmasis Lietuvoje mokslinis tyrimas, analizuojantis vaikų kiaušidžių užsisukimo priežastis, optimalius diagnostikos kriterijus, chirurginio gydymo taktiką ir metodus bei atokiuosius rezultatus. Šis atokiųjų konservatyvaus chirurginio gydymo rezultatų tyrimas yra didžiausias pasaulyje. Darbe nustatyta, kad 54,7 % kiaušidės užsisukimo priežasčių buvo įgimtos anatominės; 45,3 % ligonių kiaušidė užsisuko dėl patologinių darinių. Ligonėms iki menarchės statistiškai patikimai dažniau rasta brandžių teratomų (p=0,03). Specifinių vaikų kiaušidės užsisukimo simptomų ir požymių nenustatyta. Iki operacijos, tiriant echoskopu, užsisukusi kiaušidė buvo didesnė nei sveikoji vidutiniškai 21,48 (17,06) karto. Leukocitozė ir kiaušidės kraujotakos sutrikimai statistiškai patikimai dažnesni mergaitėms, kurioms kiaušidė pašalinta. Nė vienai mergaitei, kuriai kiaušidė buvo atsukta ir palikta pilvo ertmėje, nebuvo trombembolijos ir peritonito, nė vienai nerasta piktybinio naviko. Remiantis patologijos histologijos tyrimais, nustatyta, kad 14-oje (82,35 %) pašalintų kiaušidžių nekrozės ir patologinių darinių nebuvo, todėl jos galėjo būti išsaugotos. Patikrintų 95,24 % mergaičių ir moterų atsuktos kiaušidės anatomija ir folikulogenezė išliko normali. / Ovarian torsion is a rare children’s acute abdominal disease which is difficult to diagnose and there is no consensus among scientists how to treat it. This is the first scientific research in Lithuania which analyses causes, optimal diagnostic criteria, the strategy, methods of surgical treatment and follow-up results of ovarian torsion in children. This is the largest research of the follow-up results of the conservative surgical treatment in the world. It was identified during the research that as many as 54.7% of the causes of ovarian torsion were congenital anatomical. In the case of 45.3% of the patients ovarian torsion was caused by pathological derivatives. In patients before menarche there were statistically significantly more mature teratomas (p=0.03). No specific symptoms of ovarian torsion in children were identified. Prior to the surgery, ultrasonography showed that the twisted ovary was on average 21.48 (17.06) times larger than the healthy ovary. Leukocytosis and ovarian blood flow disorders were statistically significantly more common in the case of ovarectomy. None of the girls who underwent detorsion with the ovary left in the abdominal cavity had thromboembolism or peritonitis; no malignant tumour was detected in any girl. According to the histopathological findings, no necrosis was detected in 14 (82.35%) removed ovaries, therefore they could be salvaged. Normal ovarian anatomy and folliculogenesis were retained in 95.24% of girls and women who were... [to full text]

Les propriétés généralement demandées aux armatures pour béton armé doivent répondre à des exigences particulières précisées dans des normes nationales, européennes et internationales. Actuellement, dans la pratique de la production de l'acier à béton, on tend à substituer différentes nuances d'armature par une armature unifiée ayant une valeur de limite d'élasticité minimale de 500 MPa. Le remplacement des ronds à béton de nuance 400MPa par cette armature conduit à une économie de métal de l'ordre de 10-20 % d'après les estimations de différents spécialistes.Il existe, généralement, plusieurs techniques de fabrication des armatures, dont la déformation à chaud suivie d'un refroidissement accéléré sous flux d'eau (traitement thermomécanique ou Thermomechanical Control Process - TMCP), ainsi que la déformation à froid (tréfilage â travers une filière conique et une filière à rouleaux, microlaminage...), qui se heurte cependant â l'impossibilité de satisfaire aux exigences des Normes vis-à-vis des propriétés de résistance (Re > 500MPa) et de plasticité.Le présent travail a pour but le développement d'un procédé combiné de production d'acier à béton profitant des aspects positifs de deux types de déformation à chaud ainsi qu'à froid, sous forme du traitement combiné mécano-thermomécanique (post déformations à froid après le TMCP). et d'étudier la possibilité de production d'aciers à béton de qualité 500 MPa (B(A)500), de petits diamètres, en couronne, répondant aux exigences des Normes modernes. L'objectif scientifique de ce travail est d'étudier les mécanismes microstructuraux qui se produisent lors de la déformation à froid de l'acier préalablement traité thermomécaniquement et leurs conséquences sur l'évolution des propriétés mécaniques.Plusieurs nuances d'acier bas carbone de différents diamètres ont été étudiées. De nombreuses techniques de caractérisation macroscopique et microscopique de la structure de l'acier ont été utilisées: traction monotone, essais de microdureté, microscopie optique, microscopie électronique â balayage (MEB) et en transmission (MET), diffraction des rayons X. spectrométrie mécanique..Les résultats des essais montrent qu'il est possible d'obtenir avec assurance l'armature de qualité B(A)500, possédant des propriétés mécaniques qui dépassent les exigences des nonnes, à l'aide d'une déformation par torsion avec un cisaillement maximal de 22%, pour des aciers à 0.15 -0.2 % C(en poids), faiblement alliés en Mn et Si et traités themomécaniquement. La déformation par torsion provoque une augmentation de dureté en surface mais aussi au cœur de l'armature. Cette augmentation de dureté à cœur peut être amplifiée par le traitement thermique de vieillissement à 100°C correspondant à l'utilisation en Génie Civil. Cet effet, lié aux interactions dislocation-impuretés interstitielles, a été expliqué grâce â la MET et à l'étude du frottement intérieur.

Delayed or impaired bone healing occurs in 5-10% of all fractures, yet cost effective solutions to enhance the healing process are limited. Lithium, a current treatment for bipolar disorder, is not clinically indicated for use in fracture management, but has been reported to positively influence bone biology. The objective of this study was to identify lithium administration parameters that maximize bone healing in a preclinical, rodent femur fracture model. Using a three factor, two level, design of experiments (DOE) approach, bone healing was assessed through mechanical testing and μCT-image analysis. Significant improvements in healing were found at a low dose, later onset, longer duration treatment combination, with onset identified as the most influential parameter. The positive results from this DOE screening focuses the optimization phase towards further investigation of the onset component of treatment, and forms a crucial foundation for future studies evaluating the role of lithium in fracture healing.

Methylation is involved in the regulation of varied biological processes, from cancer to embryonic development. In B-DNA, methylation can alter the frequency with which a dinucleotide step samples one of two substates: BI and BII. Changing the BI-BII equilibrium can in turn affect the ability of proteins to bind to DNA, which may ultimately alter the transcription of genes. Using MD simulations, we evaluate the effects of cytosine methylation on the BI-BII equilibrium and the RMS atomic fluctuations of the backbone of two sequences: (GC)5 and the Dickerson dodecamer (DD). Methylation in (GC)5 stabilizes the BII state in CpG steps and stabilizes the BI state in GpC steps, but the BII state is always less favored than the BI state. The activation energy between the BI/BII states in (GC)5 increases in GpC steps and decreases in CpG steps upon methylation, indicating that backbone dynamics are affected by methylation in a step-dependent manner. The DD simulations suggest that methylation stabilizes the BII state in both CpG and GpC steps, although more sampling is needed to determine the significance of these results. Methylation has little effect on the atomic fluctuations of the backbone in (GC)5 or DD simulations. Thus, in these sequences, methylation does not uniformly stabilize one state, nor does methylation stabilize the state that is favored in the native sequence.

This thesis describes a non-linear finite element model suitable for the analysis of reinforced concrete, or steel, structures under general three-dimensional states of loading. The 20 noded isoparametric brick element has been used to model the concrete and reinforcing bars are idealised as axial members embedded within the concrete elements. The compressive behaviour of concrete is simulated by an elasto-plastic work hardening model followed by a perfectly plastic plateau which is terminated at the onset the . crushing. In tension, a smeared crack model with fixed orthogonal cracks has been used with the inclusion of models for the retained post-cracking stress and the reduced shear modulus. The non-linear equations of equilibrium have been solved using an incremental-iterative technique operating under load control. The solution algorithms used are the standard and the modified Newton-Raphson methods. Line searches have been implemented to accelerate convergence. The numerical integration has been generally carried out using 15 point Gaussian type rules. Results of a study to investigate the performance of these rules show that the 15 point rules are accurate and computationally efficient compared with the 27(3X3X3) point Gaussian rule. The three- dimensional finite element model has been used to investigate the problem of elasto-plastic torsion of homogeneous members. The accuracy of the finite element solutions obtained for beams of different cross-sections subjected to pure and warping torsion have been assessed by comparing them with the available exact or approximate analytical solutions. Because the present work is devoted towards the analysis of reinforced concrete members which fail in shear or torsional modes, the computer program incorporates three models to account for the degradation in the compressive strength of concrete due to presence of tensile straining of transverse reinforcement. The numerical solutions obtained for reinforced concrete panels under pure shear and beams in torsion and combined torsion and bending reveal that the inclusion of a model for reducing the compressive strength of cracked concrete can significantly improve the correlation of the predicted post-cracking stiffness and the computed ultimate loads with the experimental results. Parametric studies to investigate the effects of some important material and solution parameters have been carried out. It is concluded that in the presence of a compression strength reduction model, the tension-stiffening parameters required for reinforced concrete members under torsion should be similar to those used for members in which bending dominates.

In recent work, N. Hitchin described special geometries in terms of a variational problem for closed generic $p$-forms. In particular, he introduced on 8-manifolds the notion of an integrable $PSU(3)$-structure which is defined by a closed and co-closed 3-form. In this thesis, we first investigate this $PSU(3)$-geometry further. We give necessary conditions for the existence of a topological $PSU(3)$-structure (that is, a reduction of the structure group to $PSU(3)$ acting through its adjoint representation). We derive various obstructions for the existence of a topological reduction to $PSU(3)$. For compact manifolds, we also find sufficient conditions if the $PSU(3)$-structure lifts to an $SU(3)$-structure. We find non-trivial, (compact) examples of integrable $PSU(3)$-structures. Moreover, we give a Riemannian characterisation of topological $PSU(3)$-structures through an invariant spinor valued 1-form and show that the $PSU(3)$-structure is integrable if and only if the spinor valued 1-form is harmonic with respect to the twisted Dirac operator. Secondly, we define new generalisations of integrable $G_2$- and $Spin(7)$-manifolds which can be transformed by the action of both diffeomorphisms and 2-forms. These are defined by special closed even or odd forms. Contraction on the vector bundle $Toplus T^*$ defines an inner product of signature $(n,n)$, and even or odd forms can then be naturally interpreted as spinors for a spin structure on $Toplus T^*$. As such, the special forms we consider induce reductions from $Spin(7,7)$ or $Spin(8,8)$ to a stabiliser subgroup conjugate to $G_2 times G_2$ or $Spin(7) times Spin(7)$. They also induce a natural Riemannian metric for which we can choose a spin structure. Again we state necessary and sufficient conditions for the existence of such a reduction by means of spinors for a spin structure on $T$. We classify topological $G_2 times G_2$-structures up to vertical homotopy. Forms stabilised by $G_2 times G_2$ are generic and an integrable structure arises as the critical point of a generalised variational principle. We prove that the integrability conditions on forms imply the existence of two linear metric connections whose torsion is skew, closed and adds to 0. In particular we show these integrability conditions to be equivalent to the supersymmetry equations on spinors in supergravity theory of type IIA/B with NS-NS background fields. We explicitly determine the Ricci-tensor and show that over compact manifolds, only trivial solutions exist. Using the variational approach we derive weaker integrability conditions analogous to weak holonomy $G_2$. Examples of generalised $G_2$- and $Spin(7)$ structures are constructed by the device of T-duality.

Most of the current optimization techniques for the design of light-weight structures are unable to generate structural alternatives at the concept stage of design. This research tackles the challenge of developing an optimization method for the early stage of design. The main goal is to propose a procedure to optimize material and shape of stiff shafts in torsion. / Recently introduced for bending stiffness design, shape transformers are presented in this thesis for optimizing the design of shafts in torsion. Shape transformers are geometric parameters defined to classify shapes and to model structural efficiency. The study of shape transformers are centered on concept selection in structural design. These factors are used to formulate indices of material and shape selection for minimum mass design. An advantage of the method of shape transformers is that the contribution of the shape can be decoupled from the contribution of the size of a cross-section. This feature gives the designer insight into the effects that scaling, shape, as well as material have on the overall structural performance. / Similar to the index for bending, the performance index for torsion stiffness design is a function of the relative scaling of two cross-sections. The thesis examines analytically and graphically the impact of scaling on the torsional efficiency of alternative cross-sections. The resulting maps assist the selection of the best material and shape for cross-sections subjected to dimensional constraints. It is shown that shape transformers for torsion, unlike those for bending, are generally function of the scaling direction. / The efficiency maps ease the visual contrast among the efficiency of open-walled cross-sections and that of close-walled cross-sections. As expected, the maps show the relative inefficiency of the former compared to the latter. They can also set the validity range of thin- and thick-walled theory in torsion stiffness design. The analytical results are validated with the numerical data obtained from ANSYS to guarantee the consistency of the models. The thesis concludes with three case studies that demonstrate the method.

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