Polarization control and sensing with two-dimensional coupled photonic crystal microcavity arrays

We have experimentally studied polarization properties of the two-dimensional coupled photonic crystal microcavity arrays, and observed a strong polarization dependence of the transmission and reflection of light from the structures - the effects that can be employed in building miniaturized polarizing optical components. Moreover, by combining these properties with a strong sensitivity of the coupled bands on the surrounding refractive index, we have demonstrated a detection of small refractive index changes in the environment, which is useful for construction of bio-chemical sensors.Comment: 8 pages text and 4 figures on 4 pages. Submitted for publication on 07/14/0

COMPARISON OF ULTRASONOGRAPHIC PLACENTA EXAMINATION WITH PATHOHISTOLOGIC VERIFICATION OF FETAL ANOMALIES

Ultrasonographic diagnostics is a sovereign diagnostic method of discovering disorders in growth and development of embryo. The main aim of this research is The Comparison of Ultrasonographic Placenta Examination with Pathohistologic Treatment of Placenta considering those pregnancies previously verified to have embryo anomalies and which were ended by the procedure of feticide. During the period of 2001 – 2004, 15 pregnant women, with gestation between the 24th and 28th week, were hospitalized in our clinic. Ultrasonographic placenta examination was carried out during the expertise sonography immediately before deciding to commit feticide. The descriptive medical findings were divided into the clinical entities estimating the continuity of basal body, insertion, volume, and echo-structure of placenta substance. The procedure of feticide was carried out in regular treatments using intracardial application of 7,4 % KCl or transabdominal, intra-amnial instillation of 20 % NaCl under the control of ultrasound.The patients with the embryo anomalies were divided into three groups:I – the group with the diagnosis of embryo hydrocephalusII – the group with the diagnosis of other anomalies of growth of embryo's CNSIII – the group of patients with other embryo anomaliesPathohistologic placenta examinations were carried out in the Department of Pathology and Forensic Medicine in CC Kragujevac.The ultrasonographic placenta finding of the patients with the different embryo anomalies was not statistically very different (x2 – test; p=0,073). However, besides the lack of significant difference, what is reasonable considering the size of the sample, we notice quite different ultrasonographic findings of the placenta examination of the patients having the embryo with hydrocephalus in comparison to those patients having the other embryo anomalies of CNS. The ultrasonographic placenta examination of the patients having the other embryo anomalies was similar to the finding of the patients having the embryo with hydrocephalus, and the most frequent finding in the group with hydrocephalus was cystic degeneration of placenta, and in the group with the other hydrops placenta anomalies. Among the groups of patients with different placenta anomalies, statistically significant difference was not noticed in the pathohistologic finding obtained by placenta examination (x2 – test; p=0,955).Ultrasonography is a sovereign, non-invasive diagnostic procedure in antenatal pro-tection of pregnant women. If we doubt that there is inadequate growth and development of embryo, such pregnancy must be correctly diagnosed and treated as soon as possible, ideally until the 22nd week of gestation

The freudenthal space for approximate systems of compacta and some applications

In this paper we define a space $\sigma (\underline{\bold X})$ for approximate systems of compact spaces. The construction is due to H. Freudenthal for usual inverse sequences \cite{4, p. 153--156}. We stablish the following properties of this space: (1) The space $\sigma(\underline{\bold X})$ is a paracompact space, (2) Moreover, if $\underline{\bold X}$ is an approximate sequence of compact (metric) spaces, then $\sigma(\underline{\bold X})$ is a compact (metric) space (Lemma 2.4). We give the following applications of the space $\sigma(\underline{\bold X})$: (3) If $\underline{\bold X}$ is an approximate system of continua, then $X=\lim \underline{\bold X}$ is a continuum (Theorem 3.1), (4) If $\underline{\bold X}$ is an approximate system of hereditarily unicoherent spaces, then $X=\lim \underline{\bold X}$ is hereditarily unicoherent (Theorem 3.6), (5) If $\underline{\bold X}$ is an approximate system of trees with monotone onto bonding mappings, then $X=\lim\underline{\bold X}$ is a tree (Theorem 3.13)

Urban sprawl analysis in Kutupalong Refugee Camp, Bangladesh

Dissertation presented as the partial requirement for obtaining a Master's degree in Geographic Information Systems and ScienceUrban sprawling is a common phenomenon associated with geographical and political challenges such as refugee settlements and environmental extremes. Urban sprawl related to refugee or habitation settlement has been an area of active interest because of humanitarian and environmental problems. For example, higher rates of urban sprawling are positively correlated with higher rates of deforestation. The present study explored the viability and reproducibility of different classification techniques in assessing urban sprawl among Rohingya refugees in the Kutupalong refugee camp in South-Eastern Bangladesh. Two classification techniques were used to assess the urban sprawl among the study population. These classifications include the Support Vector Machine and Maximum Likelihood Classifier. The sprawl was measured based on the classification of urban ad non-urban classes, according to the topography of the camps. The study showed that urban class exhibited exponential growth from 2.01 km2 to 5.37 km2 within nine months based on Support Vector Machine Classifier, while Maximum Likelihood Classification detected 3.2 km2 to 7.8 km2 of urbanization. On the contrary, the non-urban class shrunk from 12.58 km2 to 9.95 km2 during the same period with Support Vector Machine and 11.3 km2 to 6.7 km2 with Maximum Likelihood Classification. The Support Vector Machine yielded better overall accuracy performance compared to Maximum Likelihood Classification

Photonic Crystal Nanocavities and Waveguides

Fabrication of optical structures has evolved to a precision which allows us to control light within etched nanostructures. Nano-optic cavities can be used for efficient and flexible concentration of light in small volumes, and control over both emission wavelength and frequency. Conversely, if a periodic pattern is defined in the top semitransparent metal layer by lithography, it is possible to efficiently couple out the light out of a semiconductor and to simultaneously enhance the spontaneous emission rate. Here we demonstrate the use of photonic crystals for efficient light localization and light extraction