Polarimetric Modelling for Anisotropic Stars

A theoretical description of the polarization of light, generated by an anisotropic point light source and scattered by an arbitrary shape envelope, is developed in this work, the mechanism of scattering being assumed to be either Thomson or Rayleigh scattering. The description is a development of the earlier work of J. F. L. Simmons' (1982) where he expressed the scattering function and scatterer density distribution function as a summation of multipole contributions. Whereas Simmons analysis was based on an isotropic point light source, the present analysis permits a variable flux to represent the anisotropy of the light source. Thomson or Rayleigh scattering is assumed throughout, and in all cases the scattering envelope is taken to be large compared to the light source. This allows the anisotropy to be expressed in terms of projected area. The model has applicability to rotating, pulsating, binary, and active stars with hot extended envelopes. The thesis is divided into five chapters plus four appendices. Following a review of previous work in Chapter One, together with a discussion of the motivation and interest of stellar polarimetry, in Chapter Two the theoretical analysis is established for scattering polarization with an anisotropic point light source within a spherical envelope. This analysis is then applied to an ellipsoidal black body star within a spherical envelope, for which we get explicit integral expressions for the Stokes' parameters and an analytical solution for the special case of a star with a circular equator. As examples of ellipsoidal stars the polarization from a single distorted star (due to e. g. the rotation) such as Be stars, X-ray binaries filling its Roche lobe (e. g. Cygnus X-1 and Centaurus X-3) , and pulsating stars (pulsating as a series of ellipsoids) is calculated. The latter show a very complicated pattern of qu-loci, which, in principle, fit the polarization behaviour of such types as RV Tau and Omicron Ceti. The maximum polarization of about 20% of the total light is expected from a disk like light source viewed edge on (Galaxies would be good example, since they are very distorted light sources). In Chapter Three the anisotropic light source theory is generalized to include an arbitrarily shaped envelope. In the harmonic summation which results it is found that approximation up to the second order terms is quite acceptable, when both the light source and the envelope are ellipsoidal. The maximum polarization is enhanced (due to the envelope being ellipsoidal) to about 35% when a disk of scatterers is perpendicular to the disk like star observed edge on. In general whether the polarization undergoes enhancement or cancellation is dependent on the angle between the rotation axis of the ellipsoidal star and the axis of symmetry of the ellipsoidal envelope. The effects of rotation and pulsation are also calculated. In Chapter Four the analysis is applied to the case of light source anisotropy arising from a non-uniform photosphere (e. g. hot or cool spot). Calculation of the projected area of the spot as it varies during stellar rotation is done without any of the simplifying assumptions usually made in stellar light curve modelling. Again the approximation of the second order terms of the harmonic summation is acceptable for spots of likely physical size (e. g. of angular extent < 3

Use of Multiplex PCR for Diagnosis of Bacterial Infection Respiratory Mixed

Atypical bacteria grow very slowly in culture or they do not grow at all leading to delays in detection and diagnosis. PCR multiplex was performed on template DNAs extracted from seventy three collected specimens. Thirty seven showed positive indication for the presence of bacterial infection. The incidence of Mycoplasma pneumoniae, Chlamydia pneumonia and Legionella pneumophila as a single infecting agent was 31.5%, 27.5% and 20 % respectively. Dual agent infection caused by Mycoplasma + Chlamydia, Mycoplasma + Legionella and Legionella + Chlamydia was 24%, 20% and 15% respectively. Triple agent infection caused by Legionella + Mycoplasma + Chlamydia was 17.5%. The etiology of the infection was M. pneumoniae, L. pneumophila or C. pneumoniae as a single etiology or in combination of two or three organisms

Effect of fire smoke on some biochemical parameters in firefighters of Saudi Arabia

<p>Abstract</p> <p>Background</p> <p>Firefighters who are facing fires, are frequently exposed to hazardous materials including carbon monoxide, hydrogen cyanide, hydrogen chloride, benzene, sulphur dioxide, etc. This study aimed to evaluate some relevant serum biochemical and blood hematological changes in activity involved firefighters in comparison to normal subjects.</p> <p>Subjects and Methods</p> <p>Two groups of male firefighters volunteered to participate in the study. The first included 28 firefighters from Jeddah, while the second included 21 firefighters from Yanbu, with overall age ranged 20–48 years. An additional group of 23 male non-firefighters volunteered from both cities as normal control subjects, of age range 20–43 years. Blood samples were collected from all volunteer subjects and investigated for some relevant serum biochemical and blood hematological changes.</p> <p>Results</p> <p>The results obtained showed that, there were statistically significant differences in liver function, kidney function, serum lipid profile, cortisol, creatine kinase, lactate dehydrogenase, iron and its biologically active derivatives, and blood picture in firefighters as compared with the normal control group. These results indicate that, fire smoke mainly affects serum biochemical and blood hematological parameters. Such results might point out to the need for more health protective and prophylactic measures to avoid such hazardous health effects that might endanger firefighters under their highly drastic working conditions.</p> <p>Conclusion</p> <p>Besides using of personal protective equipments for firefighters to protect them against exposure to toxic materials of fire smoke, it is recommended that, firefighters must be under continuous medical follow up through a standard timetabled medical laboratory investigations to allow for early detection of any serum biochemical or blood hematological changes that might happen during their active service life and to allow for early treatment whenever necessary.</p

Manufacture of Light Weight Ceramic Bodies as Thermal Insulator From Local Material

The research work covers a study of the feasibility of producing lightweight ceramic thermal insulation bodies used for lining the furnaces by adding saw dust and AlF3 to the Dewechla clay (Kaolinite).AlF3 is a chemical waste materials in the Akashat–factories in Rutba to the Dewechla clay (kaolinite). Finely distributed Saw dust and ALF3 were added to clay with different weight percentages (0, 15, 25, 35 & 40) Wt%. Cylindrical shape samples (30mm diameter and 30 mm height) were prepared by using the semi–dry method, moulding pressure was (500Kg/cm²). After drying at (110C◦), the samples were burnt at (900, 950, 1000, 1050&1100) C◦. The fired samples were investigated to obtain their properties, bulk density, porosity ,compressive strength and thermal conductivity. It was possible to produce ligh-weight ceramic thermal insulators with bulk density between (700 and 1300) Kg/m³ compressive strength not less than (25) Kg/cm² and thermal conductivity between (0.2 and 0.4) Kcal/m.h.c

Spectropolarimetric Variability and Co-Rotating Structure in HD 92207

We report on low resolution (R~3000) spectropolarimetry of the A0 supergiant star HD 92207. This star is well-known for significant spectral variability. The source was observed on seven different nights spanning approximately 3 months in time. With a rotation period of approximately 1 year, our data covers approximately a quarter of the star's rotational phase. Variability in the continuum polarization level is observed over this period of time. The polarization across the Halpha line on any given night is typically different from the degree and position angle of the polarization in the continuum. Interestingly, Hbeta is not in emission and does not show polarimetric variability. We associate the changes at Halpha as arising in the wind, which is in accord with the observed changes in the profile shape and equivalent width of Halpha along with the polarimetric variability. For the continuum polarization, we explore a spiral shaped wind density enhancement in the equatorial plane of the star, in keeping with the suggestion of Kaufer etal (1997). Variable polarization signatures across Halpha are too complex to be explained by this simple model and will require a more intensive polarimetric follow-up study to interpret properly.Comment: to appear in A

Histopathologic profile of esophageal atresia and tracheoesophageal fistula

Purpose Few reports are available in the literature on the histology of the congenital atretic esophagus in humans. Histologic abnormalities  including congenital esophageal stenosis (CES) may contribute toward the abnormal esophageal motility after successful repair of esophageal atresia (EA) and tracheoesophageal fistula (TEF). The main aim of this study is to document the histopathologic profile in cases of EA.Methods One hundred and nineteen surgical specimens were collected from 69 consecutive EA patients who underwent surgical repair at the Aseer Central Hospital, Abha, and Armed Forces Hospital Southern Region, Saudi Arabia, from May 1999 through May 2009. This included 62 cases with EA and distal TEF, five cases of pure EA, and two cases of N-type TEF. Samples from tips of the upper pouch (UP), lower pouch (LP), and mid portion of the TEF were preserved in 10% formalin, sectioned, and stained with hematoxylin and eosin.Results The combined three elements of tracheobronchial tissue were observed in only three LP specimens. Gastrictype mucosa was seen in one UP and one LP specimen. Except for one N-type fistula, all sections showed fullthickness muscle coats. Distortion of muscles by fibrosis was most commonly seen in the UP. The muscle layer in the LP was more commonly distorted by glands with or without cartilage. Fourteen samples (10.8%) showed a histological picture consistent with CES.Conclusion Glands in the submucosa may be abnormal innumber and type, and may extend to different esophageal  coats. Muscle distortion by fibrosis, glands, or cartilage and associated CES may contribute toward esophageal dysmotility and stricture after surgery. Cutting the TEF B3–5mm distal to its origin from the trachea is adequate histologically for primary anastomosis of the atretic esophagus. The histological changes associated with the TEF need to be revised.Keywords: congenital esophageal stenosis, esophageal atresia,  esophageal dysmotility, histopatholog

Epidemiology of Autoimmune Diseases among Attendants of General Hospitals in Aseer region

It has long been recognized that environmental influences play an important role in the risk of developing Autoimmune disease. Defining specific pathogenic environmental mediators that may trigger the development or progression of autoimmune disease remains a focus of increasing investigative effort. Factors promoting disease may not be identical to factors that influence the severity or progression of the disorder. The cause(s) of autoimmune disorders remain largely unknown. Considerable evidence supports a role for environmental agents in inducing autoimmune disorders. OBJECTIVES: The study aims to explore the risk factors of autoimmune diseases among attendants of general hospitals in Aseer Region. Methods: case control study design was carried out  included 70  patients with multiple types of auto immune diseases attending general hospitals and primary health care centers in Abha city. They were clinically diagnosed as having autoimmune diseases. and 140 clinically free subjects , age and sex matched were included as controls. RESULTS: The present study included 70 autoimmune disease patients predominantly females (88.4%). Their mean age was 42.7 ± 12.1 years and disease duration was 11.2 ± 7.2 years. The mean age of the control group was 47.1 ± 13.6 years with no significant differences in the demographic data between the patients and control (p &gt; 0.05). This study found no significant differences between cases with autoimmune diseases and sociodemographic characteristics. Conclusion :There is multiple determinants and risk factors affecting the occurrence of autoimmune diseases. Familial history, psychological stresses, hormonal supplementation, using hair dyes, smoking and recent vaccination were significant factors associated with autoimmune diseases. Keywords: Epidemiology, autoimmune, diseases, Aseer regio

Scattering polarization due to light source anisotropy

We consider the polarization arising from scattering in an envelope illuminated by a central anisotropic source. Spherical harmonics are used to describe both the light source anisotropy and the envelope density distribution functions of the scattering particles. This framework demonstrates how the net resultant polarization arises from a superposition of three basic "shape" functions: the distribution of source illumination, the distribution of envelope scatterers, and the phase function for dipole scattering. Specific expressions for the Stokes parameters and scattered flux are derived for the case of an ellipsoidal light source inside an ellipsoidal envelope, with principal axes that are generally not aligned. Two illustrative examples are considered: (a) axisymmetric mass loss from a rapidly rotating star, such as may apply to some Luminous Blue Variables, and (b) a Roche-lobe filling star in a binary system with a circumstellar envelope. As a general conclusion, the combination of source anisotropy with distorted scattering envelopes leads to more complex polarimetric behavior such that the source characteristics should be carefully considered when interpreting polarimetric data.Comment: to appear in A&