Using topological sweep to extract the boundaries of regions in maps represented by region quadtrees

A variant of the plane sweep paradigm known as topological sweep is adapted to solve geometric problems involving two-dimensional regions when the underlying representation is a region quadtree. The utility of this technique is illustrated by showing how it can be used to extract the boundaries of a map in O(M) space and O(Ma(M)) time, where M is the number of quad tree blocks in the map, and a(·) is the (extremely slowly growing) inverse of Ackerman's function. The algorithm works for maps that contain multiple regions as well as holes. The algorithm makes use of active objects (in the form of regions) and an active border. It keeps track of the current position in the active border so that at each step no search is necessary. The algorithm represents a considerable improvement over a previous approach whose worst-case execution time is proportional to the product of the number of blocks in the map and the resolution of the quad tree (i.e., the maximum level of decomposition). The algorithm works for many different quadtree representations including those where the quadtree is stored in external storage

Electron Paramagnetic Resonance Imaging and Probes

EPR imaging at low frequency is an important method to measure in vivo physiology. Because native paramagnetic species exist at low concentrations in living systems, exogenous paramagnetic species are needed for in vivo EPR. Selection of the appropriate EPR probe allows the experimenter to obtain information about the environment of the imaged probe and its spatial distribution. Relaxation times for several nitroxide radicals were studied with the aim of understanding the relaxation mechanisms, which provides criteria for design of suitable in vivo imaging probes. Amino-substituted trityl radicals have the potential to monitor pH in vivo, and the suitability for this application depends on spectral properties. Electron spin relaxation times T1 and T2 were measured at X-band for the protonated and deprotonated forms of two amino-substituted triaryl methyl radicals. T1 exhibits little dependence on protonation, which makes it useful for measuring O2 concentration. Values of T2 vary substantially with pH, reflecting a range of dynamic processes, and thus T2 is a potentially useful monitor of pH. The spin-lattice relaxation rates at 293 K for three anionic semiquinones (2,5-di-t-butyl-1,4-benzosemiquinone, 2,6-di-t-butyl-1,4-benzosemiquinone, and 2,3,5,6-tetramethoxy-1,4-benzosemiquinone) were studied at up to 8 frequencies between 250 MHz and 34 GHz in ethanol or methanol solution containing high concentrations of OH-. The relaxation rates are about a factor of 2 faster at lower frequencies than at 9 or 34 GHz when measured in solvent with normal isotope abundance. However, in perdeuterated alcohols the relaxation rates exhibit little frequency dependence. The relaxation rates were modeled as the sum of two frequency-independent contributions (spin rotation and a local mode) and two frequency-dependent contributions (modulation of dipolar interaction with solvent nuclei and a much smaller contribution from modulation of g anisotropy). The correlation time for modulation of the interaction with solvent nuclei is longer than the tumbling correlation time and is attributed to hydrogen bonding of the alcohol to the oxygen atoms of the semiquinones. Rapid scan imaging was shown, for the same data acquisition time, to give higher signal-to-noise than continuous wave for the nitroxide probe 15N-perdeuterated tempone. The narrow spectral widths for the amino-substituted triaryl methyl radicals facilitate spectral-spatial EPR imaging. A phantom was imaged using rapid scan to test the feasibility of mapping the pH and to test a new algorithm for full spectrum imaging. Finally, a spin coherence phenomenon was observed at X-band in semiquinone rapid scan spectra, which arises from closely-spaced nuclear hyperfine lines

Chaotic motion in multi-black hole spacetimes and holographic screens

We investigate the geodesic motion in $D-$dimensional Majumdar-Papapetrou multi-black hole spacetimes and find that the qualitative features of the D=4 case are shared by the higher dimensional configurations. The motion of timelike and null particles is chaotic, the phase space being divided into basins of attraction which are separated by a fractal boundary, with a fractal dimension $d_B$. The mapping of the geodesic trajectories on a screen placed in the asymptotic region is also investigated. We find that the fractal properties of the phase space induces a fractal structure on the holographic screen, with a fractal dimension $d_B-1$.Comment: 8 pages, 5 figure

Investigating the behaviour of ASHRAE, Bedford, and Nicol thermal scales when translated into the Arabic language

With the global spread of thermal comfort studies, thermal scales are translated into different languages to adapt local context in which the studies are applied. However, translating thermal comfort studies does not maintain the scales' behaviour associated with the original English versions. Behaviour differences include irregular categories' width, asymmetry, and deviation of the middle category centre from the centre of the thermal continuum. These differences have a negative influence on the results of thermal comfort studies and their accuracy. Applying the successive categories method, this paper explores the change in ASHRAE, Bedford, and Nicol scales' behaviour when translated into the Arabic language. The translated scales were integrated into questionnaires distributed among female high school students in Muscat, the capital city of Oman, as part of a larger survey that lasted for a whole year. The findings revealed the deviation of the translated scales from the original assumptions of the English versions. This included categories' irregular widths and asymmetry in addition to the deviation of the centre of the middle categories from the centre of the thermal continuum. Besides, it was found that both ASHRAE and Bedford scales covered different ranges on the thermal continuum, which questions their assumed equivalence. Based on these findings, the accuracy of the thermal comfort analysis is negatively affected. Considering the sensitivity of scales' behaviour to the used phrases, further explorations implementing the terms examined in this study are recommended. Abstract With the global spread of thermal comfort studies, thermal scales are translated into different languages to adapt local context in which the studies are applied. However, translating thermal comfort studies does not maintain the scales' behaviour associated with the original English versions. Behaviour differences include irregular categories' width, asymmetry, and deviation of the middle category centre from the centre of the thermal continuum. These differences have a negative influence on the results of thermal comfort studies and their accuracy. Applying the successive categories method, this paper explores the change in ASHRAE, Bedford, and Nicol scales' behaviour when translated into the Arabic language. The translated scales were integrated into questionnaires distributed among female high school students in Muscat, the capital city of Oman, as part of a larger survey that lasted for a whole year. The findings revealed the deviation of the translated scales from the original assumptions of the English versions. This included categories' irregular widths and asymmetry in addition to the deviation of the centre of the middle categories from the centre of the thermal continuum. Besides, it was found that both ASHRAE and Bedford scales covered different ranges on the thermal continuum, which questions their assumed equivalence. Based on these findings, the accuracy of the thermal comfort analysis is negatively affected. Considering the sensitivity of scales' behaviour to the used phrases, further explorations implementing the terms examined in this study are recommended

Using a New Programme to Predict Thermal Comfort as a Base to Design Energy Efficient Buildings

A strong relationship relates the thermal comfort and the consumption of energy, especially in the hot arid climate where the installation of HVAC systems is unavoidable. In fact, it has been reported that the HVAC systems are responsible for consuming huge amounts of the total energy used by the buildings that can globally reach up to 40% of the total primary energy requirement. The future estimations indicate that the energy consumption is likely to continue growing in the developed economies to exceed that of the developed countries in 2020. Under these situations, it seems that the shift towards more energy efficient buildings is not an option. Because part of any successful environmental design is to understand the potentials of the site, the proposed programme (THERCOM) assists in weighing the indoor and outdoor thermal comfort in different climates in order to provide better understanding of the site environment as well as testing the thermal comfort chances of the initial concepts

An Addition to the Ohio Records of Millepedes

Author Institution: Department of Zoology and Entomology, The Ohio State University, Columbus 1

Mucous membrane pemphigoid

Mucous membrane pemphigoid (MMP) is the subgroup of pemphigoid which predominantly affects mucous membranes. Scarring and limited skin involvement are possible. Several subtypes are classified based on clinical symptoms and target antigens, such as ocular mucous membrane pemphigoid, localized vulvar pemphigoid (LVP) and anti-laminin 332 MMP (anti-LN-332 MMP). Autoantibodies are directed against various structural proteins in the epidermal basement membrane zone (EBMZ), with the 180-kD antigen (BP180) as the main target antigen. Other antigens, such as BP230, the heterotrimeric glycoprotein laminin 332 and A6B4 integrin can also be targeted by autoantibodies. Various mucosa can be affected and are histologically characterized as nonkeratinized stratified squamous epithelium. The clinically heterogeneous disease is characterized by erosions and blistering of the oral mucosa (85%), conjunctiva (30-60%), and less frequently, the nasal mucosa (20-40%), esophagus (5-15%), pharyneal (20%) or laryngeal mucosa (5-10%) and anogenital mucosa (25%). Clinical severity is highly variable in the different subtypes of MMP. Previously, the term cicatricial pemphigoid was used for MMP. Progressive scar formation is a severe complication in ocular MMP and anti-LN-332 MMP, but scarring does not occur in all patients with MMP. Patient and doctors delay is frequently seen in MMP because of the heterogeneous clinical presentation and unfamiliarity among clinicians. For an accurate diagnosis, direct immunofluorescence microscopy (DIF) and detection of circulating autoantibodies in serum is essential. The multidisciplinary management and prognosis of MMP depends on the severity and extent of the disease and involves topical corticosteroids and immunomodulatory and immunosuppressive drugs.</p

P-SELECTIN GLYCOPROTEIN LIGAND-1 GENE POLYMORPHISMS IN SUDANESE PREGNANT WOMEN WITH THROMBOSIS

Objectives: In this study we aimed to investigate whether P-selectin gene polymorphism is associated with thrombosis in Sudanese pregnant women in Khartoum state.Methods: After informed consent, 96 Sudanese pregnant women with thrombosis and 53 healthy pregnant women were recruited in the study. Genomic DNA was isolated from whole blood. Genotyping of PSGL-1 gene was performed by polymerase chain reaction amplification for exon 14 and electrophoresis.Results: The frequency of the B allele was found to be significantly higher in pregnant women with thrombosis (26%) compared to the controls (17.4%).Conclusion: The AB genotype was found to be higher in women with thrombosis 40.6% than in healthy controls 20% (p=0.02). Our results suggest that the PSGL-1 AB genotype is associated with an increased risk of thrombosis in Sudanese pregnant women