The semicircular canals detect head rotations and trigger compensatory movements that stabilize gaze and help maintain visual fixation. Mammals with large eyes and high visual acuity presumably require more precise gaze stabilization mechanisms because they experience degradation of spatial resolution at a lower threshold of uncompensated motion. Because semicircular canal radius of curvature is a primary determinant of canal sensitivity, species with large canal radii are expected to be capable of more precise gaze stabilization than species with small canal radii. Here the relationship between semicircular canal radius of curvature, eye size, and visual acuity is examined in a large sample of therian mammals. These results demonstrate that eye size and visual acuity both explain a significant proportion of the variance in mean canal radius of curvature after statistically controlling for the effects of body mass and phylogeny. These findings suggest that interspecific variation in semicircular canal radius of curvature is partly the result of selection for improved gaze stabilization in species with large eyes and acute vision. / text

Baigiamajame magistro darbe buvo lyginama ofsetinės ir fleksografinės spaudos kokybė spausdinant spalvines kontrolines skales, spalvų sutapdinimo kryžius, skiriamosios gebos elementus. Atspaudai buvo atspausdinti ofsetine lapine spaudos mašina ir siauraritinine fleksografinės spaudos mašina su centriniu spaudos cilindru. Mikroskopu buvo matuojamas spalvų sutapdinimo tikslumas, skiriamosios gebos elementų dydis. Densitometru buvo matuojamas atskirų ir binarinių spalvų rastrinių taškų santykinis plotas bei įvertintas gradacinis tikslumas. Pagal gautus kiekybinius rezultatus nustatyta, jog fleksografinės spaudos kokybė prastesnė negu ofsetinės spaudos. Darbą sudaro šios dalys: įvadas, literatūros apžvalga, kokybės reikalavimai, problemos analizė, eksperimento eiga ir rezultatų analizė, išvados, literatūros sąrašas. Darbo apimtis – 80 p. teksto be priedų, 65 pav., 43 lentelės, 18 literatūros šaltinių. / In master thesis was compared the offset and flexographic printing quality. Printing quality was evaluated using control strips, register crosses, resolving power test elements. Jobs were printed with offset sheet-fed printing press and flexographic narrow web press with central impresion cilinder. Register accuracy and resolving power were investigated using microscope. Dot area of single and binary colors wes measured with densitometer and halftone graduation characteristics were evaluated. On the basis of quantitative results it was determined that offset printing quality in comparison with flexography is higher. Master thesis comprise of folowing chapters: literature review, quality requirements, experimental, results and discusion, conclusions, references. Amount – 80 pages, 65 figures, 43 tables, 18 references.

<p>    Drift tubes (DT) are prominent tools used in Ion Mobility Spectrometry (IMS) to separate ions in the gas phase due to their difference in mobility. While prominently used for small ions (< 10nm), their use for larger particles (up to 100nm) is limited and can only be attempted at atmospheric pressure due to diffusion. A system that specializes in high sensitivity larger particles (up to 1000nm) is the Differential Mobility Analyzer (DMA), but lacks in resolution (< 10 for particles 30-1000nm). The idea behind this work is to be able to design a new IMS system based on similar<br> principles to the DT but that allows high resolution and sensitivity for a large range of sizes if possible. The primary idea revolves around the principle of non-constant linear fields to try and control the width of the ion packet as it travels through the system. The first attempt was an Inverted Drift Tube (IDT) which lacked sufficient<br> sensitivity. This was followed by the development of the Varying Field Drift Tube (VFDT) which was the first of such systems to perform better than a regular DT, but only marginally. Finally, the last version of the system included a secondary pulse and labeled High Voltage Pulse - Varying Field Drift Tube (HVP-VFDT), which solved<br> some of the issues of the VFDT and was able to achieve resolving powers of 250, 3-5 times higher than regular DT.</p> <p><br>    In the IDT system, a gas flow is used to drive the packet of ions through the drift region while a linearly increasing electric field which is in the opposite direction of the flow is used to slow down the ions and separate them. In this regime it is the largest ions that arrive at the detector first, hence the name Inverted Drift Tube.This technique would allow larger ions and particles to be detected. At the same time, the linear field can be shown to have diffusion constriction (auto-correction) properties, where the broad distributions may be narrowed in the axial direction. However, the gas flow is difficult to control well and the parabolic velocity profile of the gas flow in the tube is a unfavorable factor for the system. </p> <p><br></p> <p>    To avoid the issue of the parabolic velocity but still take into account the VFDT takes the advantage of the diffusion auto-correction, the gas flow is suppressed and a linearly decreasing field is used to drive the ions. By solving the Nernst-Planck equation, we show that the VFDT has a spatial resolving power that is much higher than that of the regular DT. A DT was built and tested using a mixture of tetraalkylammonium salts. The transformation from the raw variable arrival time distribution to collision cross section or mobility diameter is derived and the linear relationship<br> makes it simple for calibration and transformation. A resolving power of over 90 is achieved experimentally although higher resolving powers were expected theory. <br>  <br>  It turns out that the difference between theory and experiments had to do with the fact that in the VFDT, the spatial and time resolving powers are different.This<br> is due to the low drift velocity at the end of the drift tube. To increase this velocity, a high voltage pulse is applied at a certain time depending on the ion/s of interest with a new system, HVP-VFDT. The system was tested numerically and experimentally where several parameters where tested resulting in a higher resolving powers when compared with DT and VFDT systems.The simulation results showed that the transmission efficiency and resolving power can be controlled by raising or lowering the field. Overall, the experimental setup tested reached resolving powers of 250 with moderate gate pulses. The HVP-VFDT system also shows that the distribution may be narrowed over the initial one, something impossible with a real drift tube and<br> opens a myriad of possibilities, including resolving powers of several thousands under low pressure and RF fields. <br>    <br>  The next step will be to couple the system to a Mass Spectrometer which is expected to be completed in the near future. To understand how a DT works with   RF fields and low pressure, a collaboration was done with David Clemmer’s lab and his 4 meter drift tube that can achieve resolutions of 150 in Helium at 4torr. Here, we tested a set of polymers and compared the results to those acquired in Nitrogen with a DMA. The shape and structure of the polymers in the gas phase was studied showing<br> self-similar assemblies that corresponds to a globule with an appendix sticking out. <br>  <br>    </p>