Physiological changes of the visual system during pregnancy

Въведение: Зрителният анализатор преминава през редица физиологични промени по време на бременността, които трябва да се познават, тъй като в повечето случаи са преходни и безобидни. Цел и задачи: Да разгледаме физиологичните промени на зрителния анализатор, които могат да възникнат във връзка с бременността. Методи и материали: Литературен обзор Резултати: Най-честите и категорични промени по време на бременността са намаляване на вътреочното налягане и влошаване характеристиките на слъзния филм. Документирани са намаляване чувствителността на роговицата и увеличаване на дебелината и кривината й, но резултатите са противоречиви. Промените в рефракцията са най-често в посока миопизация и загуба на акомодация. Заключение: Необходимо е познаването на влиянието на бременността върху зрението с цел избягване на ненужно лечение при физиологични промени. Ефектите на бременността върху зрителната система могат да бъдат още по-добре проучени и в контекста на съществуващи патологични очни състояния биха ни отворили нови врати в изучаването на етиологията, както и лечението на някои от тях.Introduction: Visual system goes through several physiological changes during pregnancy that should be recognized because in most cases they are harmless and reversible. Aims and tasks: To make a literature review of the physiological ocular changes, that can occur during pregnancy. Methods and materials: Literature review Results: The most often and definite changes during pregnancy are lowering of intraocular pressure as well worsening of tear ? lm quality. Many changes of the cornea are shown in different studies including decreasing of its sensitivity, increasing of its thickness and curvature. Often the results are contradictory. Changes in refraction are mainly in myopisation and loss of accommodation. Conclusion: We need to know the effects of pregnancy on vision in order to avoid unnecessary treatment when the changes are physiological. The effects of pregnancy on visual system need to be better investigated and in the context of an existing pathological state they could give us more information about the causes and treatment of some diseases

The development of a position-sensitive CZT detector with orthogonal co-planar anode strips

We report on the simulation, construction, and performance of prototype CdZnTe imaging detectors with orthogonal coplanar anode strips. These detectors employ a novel electrode geometry with non-collecting anode strips in one dimension and collecting anode pixels, interconnected in rows, in the orthogonal direction. These detectors retain the spectroscopic and detection efficiency advantages of single carrier (electron) sensing devices as well as the principal advantage of conventional strip detectors with orthogonal anode and cathode strips, i.e. an N×N array of imaging pixels are with only 2N electronic channels. Charge signals induced on the various electrodes of a prototype detector with 8×8 unit cells (1×1×5 mm3)are compared to the simulations. Results of position and energy resolution measurements are presented and discussed

Analog processing of signals from a CZT strip detector with orthogonal coplanar anodes

We present the requirements, design, and performance of an analog circuit for processing the non-collecting anode strip signals from a cadmium zinc telluride (CZT) strip detector with orthogonal coplanar anodes. Detector signal simulations and measurements with a prototype are used to define the range of signal characteristics as a function of location of the gamma interaction in the detector. The signals from the non- collecting anode strip electrodes are used to define two of the three spatial coordinates including the depth of interaction, the z dimension. Analog signal processing options are discussed. A circuit to process the signals from the non- collecting anode strips and extract from them the depth of interaction is described. The circuit employs a time-over- threshold (TOT) measurement. The performance of the detector prototype with a preliminary version of this circuit is presented, and future development work is outlined

Three-dimensional imaging and detection efficiency performance of orthogonal coplanar CZT strip detectors

We report on recent three-dimensional imaging performance and detection efficiency measurements obtained with 5 mm thick prototype CdZnTe detectors fabricated with orthogonal coplanar anode strips. In previous work, we have shown that detectors fabricated using this design achieve both very good energy resolution and sub-millimeter spatial resolution with fewer electronic channels than are required for pixel detectors. As electron-only devices, like pixel detectors, coplanar anode strip detectors can be fabricated in the thickness required to be effective imagers for photons with energies in excess of 500 keV. Unlike conventional double-sided strip detectors, the coplanar anode strip detectors require segmented contacts and signal processing electronics on only one surface. The signals can be processed to measure the total energy deposit and the photon interaction location in three dimensions. The measurements reported here provide a quantitative assessment of the detection capabilities of orthogonal coplanar anode strip detectors

Simulation of the 2009 Harmanli fire (Bulgaria)

We use a coupled atmosphere-fire model to simulate a fire that occurred on August 14--17, 2009, in the Harmanli region, Bulgaria. Data was obtained from GIS and satellites imagery, and from standard atmospheric data sources. Fuel data was classified in the 13 Anderson categories. For correct fire behavior, the spatial resolution of the models needed to be fine enough to resolve the essential micrometeorological effects. The simulation results are compared to available incident data. The code runs faster than real time on a cluster. The model is available from openwfm.org and it extends WRF-Fire from WRF 3.3 release.Comment: 8 pages, 2 tables, 5 figures. 8th International Conference on Large-Scale Scientific Computations, June 6-10, 2011, Sozopol, Bulgari

Analysis of a Japan government intervention on the domestic agriculture market

We investigate an economic system in which one large agent - the Japan government changes the environment of numerous smaller agents - the Japan agriculture producers by indirect regulation of prices of agriculture goods. The reason for this intervention was that before the oil crisis in 1974 Japan agriculture production prices exhibited irregular and large amplitude changes. By means of analysis of correlations and a combination of singular spectrum analysis (SSA), principal component analysis (PCA), and time delay phase space construction (TDPSC) we study the influence of the government measures on the domestic piglet prices and production in Japan. We show that the government regulation politics was successful and leaded (i) to a decrease of the nonstationarities and to increase of predictability of the piglet price; (ii) to a coupling of the price and production cycles; (iii) to increase of determinism of the dynamics of the fluctuations of piglet price around the year average price. The investigated case is an example confirming the thesis that a large agent can change in a significant way the environment of the small agents in complex (economic or financial) systems which can be crucial for their survival or extinction.Comment: 10 pages, 6 figures presented at APFA5, Torino, Italy, 29.06-01.07.200

A conceptual design tool: a sketch and fuzzy logic based system

Abstract: A real-time sketch and fuzzy logic based prototype system for conceptual design has been developed. This system comprises four phases. In the ® rst one, the system accepts the input of online free-hand sketches, and segments them into meaningful parts by using fuzzy knowledge to detect corners and in¯ection points on the sketched curves. The fuzzy knowledge is applied to capture user' s drawing intention in terms of sketching position, direction, speed and acceleration. During the second phase, each segmented subpart (curve) can be classi® ed and identi® ed as one of the following two-dimensional primitives: straight lines, circles, circular arcs, ellipses, elliptical arcs or B-spline curves. Then, two-dimensional topology information (connectivity, unitary constraints and pairwise constraints) is extracted dynamically from the identi® ed two-dimensional primitives. From the extracted information, more accurate two-dimensional geometry can be built up by a two-dimensional geometric constraint solver. The two-dimensional topology and geometry information is then employed to further interpretation of a three-dimensional geometry. The system can not only accept sketched input but also users' interactive input of two-and three-dimensional primitives. This makes it friendly and easier to use, in comparison with`sketched input only' or interactive input only' systems. Finally, examples are given to illustrate the system