Generation of Longitudinal Flux Tube Waves in Theoretical Main-Sequence Stars: Effects of Model Parameters

Context. Continued investigation of the linkage between magneto-acoustic energy generation in stellar convective zones and the energy dissipation and radiative emission in outer stellar atmospheres in stars of different activity levels. Aims. We compute the wave energy fluxes carried by longitudinal tube waves along vertically oriented thin magnetic fluxes tubes embedded in the atmospheres of theoretical main-sequence stars based on stellar parameters deduced by R. L. Kurucz and D. F. Gray. Additionally, we present a fitting formula for the wave energy flux based on the governing stellar and magnetic parameters. Methods. A modified theory of turbulence generation based on the mixing-length concept is combined with the magneto-hydrodynamic equations to numerically account for the wave energies generated at the base of magnetic flux tubes. Results. The results indicate a stiff dependence of the generated wave energy on the stellar and magnetic parameters in principal agreement with previous studies. The wave energy flux F_LTW decreases by about a factor of 1.7 between G0V and K0V stars, but drops by almost two orders of magnitude between K0V and M0V stars. In addition, the values for F_LTW are significantly higher for lower in-tube magnetic field strengths. Both results are consistent with the findings from previous studies. Conclusions. Our study will add to the description of magnetic energy generation in late-type main-sequence stars. Our results will be helpful for calculating theoretical atmospheric models for stars of different levels of magnetic activity.Comment: 9 pages, 5 figures, 6 tables; submitted to Astronomy & Astrophysic

Nature and Disposition of the Garnet-Biotite Boundary at Balquhidder, Perthshire, Scotland

The metamorphic rocks at Balquhidder are polyphase deformed and polymetamorphosed with the D1 - D4 sequential development of structures and the M1 - M4 development of minerals generally corresponding to that expressed in nearby areas. Garnet is found throughout the area and the Barrovian garnet-isograd must have been at least 2Km above the present topography. There is no garnet-biotite boundary present. The incoming of garnet was controlled by the bulk rock composition so that garnetiferous and non-garnetiferous schists can occur in the same, or adjacent outcrops. Textural studies have shown that two phases of garnet growth occurred. The more prominent of these was during M2 when three different types were formed (G2A, G2B, G2C), two only lithologies of the Pitlochry Schist (G2A, G2C) and the other (G2B) only in the Ben Lui Schist. Growth of garnet was related to particular mineral reactions, non-instantaneous nucleation and reaction partitioning. This has been substantiated by the determination, using the electron microprobe of chlorite, muscovite, garnet, biotite, albite and hornblende compositions. Garnet-biotite and garnet-hornblende pairs permit temperatures of M2 metamorphism to be determined: 530 C - 482 C for type G2A (almandine), 423 - 410 C for type G2B (almandine) and 370 C for type G2C (spessartine-rich). The 530 C estimate for G2A is considered to represent climactic conditions and, when considered with a pressure estimate of 7Kb based on the biotite-muscovite-chlorite-quartz geobarometer, indicates a typical Barrovian heat flow of c. 27 C/Km and mid-amphibolite-facies conditions. On the basis of regional correlation of structures, the M2 metamorphism (and D1 - D2) is related to the pre-590Ma Grampian Orogeny and was followed by elevation of temperature to its peak during crustal thickening during D1 (Tay Nappe formation). A second phase of garnet growth took place post-D2 - pre-D4 (possibly post-D2 - pre-D3). Temperature of development of G2-4 (?G2-3) was 377 C for a spessartine-rich type, i. e. in the green schist facies. The elevation of temperature is related to the c. 500Ma event demonstrated elsewhere in the Highlands on the basis of isotopic studies and during which crustal thickening is postulated. Previous interpretations of the presence of an inverted garnet isograd are not substantiated by this investigation. The structural development does not permit inversion of M2 or M2-4 geotherms by tectonic activity, while the distribution of garnet throughout the area does not permit the presence of any isograd to be demonstrated. Rather the whole area is within the garnet zone. Two of the previous interpretations, which suggest an inverted zonal distribution, recognized neither the composition - nucleation - reaction partitioning controls nor the polyphase development of garnet. One sets out a position for a "garnet isograd" that corresponds to the prominent development of G2A and G2C garnets in particular flat-lying units of the Pitlochry Schist. The other sets out a position for a "garnet isograd" that corresponds to the prominent development of G2B and G2-4 garnets in particular units of the Ben Lui Schist. These interpretations are rejected on the basis of the detailed evidence set out here. D4 and post-D4 mineralogical expressions only result in minor modifications to the earlier formed features. D4 is correlated with the regionally expressed c. 460Ma period of uplift and post-D4 mineral growth was both prograde and retrograde. The deformation and metamorphic history in the Balquhidder area generally corresponds to, and may be representative of, Caledonian activity in at least considerable parts of the SW Highlands

Hepatic encephalopathy: a neurochemical, neuroanatomical, and neuropsychological study.

Hepatic encephalopathy (HE) is normally diagnosed by neuropsychological (NP) tests, which are not very specific and do not reveal the underlying pathology. Magnetic resonance imaging (MRI) and spectroscopy (MRS) of the brain offer alternative and possibly more specific markers for HE. These methods were applied in conjunction with NP testing in order to determine their usefulness in the identification of HE and to understand the pathogenesis of HE more clearly. MR imaging and spectroscopy examinations, in addition to a battery of 15 NP tests, were administered to investigate 31 patients awaiting liver transplantation and 23 healthy controls. MR image intensities from the globus pallidus region were calculated and normalized to those of the thalamus. Absolute concentrations and ratios with respect to creatine (Cr) of several metabolites were computed from MR spectra. The MR data were correlated with the results of NP tests. The patients showed impairment in NP tests of attention and visuospatial and verbal fluency. In T1-weighted MRI, the relative intensity of the globus pallidus with respect to that of the thalamus region was significantly elevated in patients and correlated(negatively) with three NP tests (Hooper, FAS, and Trails B). The absolute concentrations of myo-inositol (mI) and choline (Ch) were significantly reduced in three brain regions. In addition, the absolute concentrations of glutamine (Gln) and combined glutamate and glutamine (Glx) were increased in all three locations, with Gln increase being significant in all areas while that of Glx only in the occipital white matter. In summary, this study partially confirms a hypothesized mechanism of HE pathogenesis, an increased synthesis of glutamine by brain glutamate in astrocytes due to excessive blood ammonia, followed by a compensatory loss of myo-inositol to maintain astrocyte volume homeostasis. It also indicates that the hyperintensity observed in globus pallidus could be used as complementary to the NP test scores in evaluating the mental health of HE patients

Respuesta química y eficacia agronómica de cultivos de girasol (Helianthus agnnuus L.) a fuentes de nitrógeno orgánico y fertilizantes convencionales nitrogenados en suelos áridos

Sunflower (Helianthus annuus L.) is an option for oilseed production, particularly in dry land areas due to good root system development. In this study, two field experiments were performed in the El-Khattara region (Sharkia Governorate, Egypt) during the 2005 season. The objective of this research was to determine the effect of organicnitrogen (ON) sources and their combinations as well as to compare the effect of ON and ammonium sulfate (AS) as a conventional fertilizer added individually or in combination on growth, yield components, oil percentage and the uptake of some macronutrients by sunflowers grown on sandy soil. The treatments of chicken manure (CM) and a mixture of farmyard manure (FYM) with CM were superior to the other treatments and gave the highest yield, dry matter yield, NPK uptake by plants at all growth stages along with seed yield at the mature stage. The effect of the different ON on crop yield and its components may follow the order; CM> palma residues (PR)> FYM. This was more emphasized when the materials were mixed with AS at a ratio of 3:1 and 1:1. The uptake of nitrogen (N), phosphorus (P) and potassium (K) by plants was affected by the addition of different N sources and treatments. The highest nutrient content and uptake by straw were obtained when treated with CM followed by PR at all growth stages, while it was PR followed by CM for seeds. Oil recovery was shown to respond to the N supply and the changes in individual fatty acids were not statistically different. However, it seems that the application of organic fertilizers resulted in an increase in total unsaturated fatty acids compared to the control.El girasol (Helianthus annuus) es una opción para la producción de semillas oleaginosas, en particular en terrenos arenosos debido al buen desarrollo de sus raíces. En este trabajo, dos estudios de campo fueron realizados en la región de El-Ishattara (Sharkia Governorate, Egypt) durante la estación 2005. El efecto de diversas fuentes de nitrógeno orgánico (ON) y el de su combinación, así como el efecto de ON y sulfato amónico (AS) como fertilizante convencional añadido individualmente o en combinación ha sido estudiado en base a su crecimiento, rendimiento de los componentes, porcentaje de aceite y consumo de micronutrientes en girasoles crecidos en suelos arenosos. El tratamiento con estiércol de pollo (CM) y una mezcla de estiércol de corral (FYM) con CM fue superior a otros tratamientos y dio el más alto rendimiento, la mayor cantidad de materia seca, y el mayor consumo de NPK por la planta en todos los estadios de crecimiento, así como en el rendimiento de la semilla en el estado de madurez El efecto promotor de los diferentes ON en el rendimiento del cultivo y sus componentes puede seguir el orden siguiente: CM> residuos de palma (PR)> FYM. Este efecto fue mayor cuando los materiales fueron mezclados con AS en una proporción 3:1 y 1:1. El consumo de nitrógeno (N), fósforo (P) y potasio (K) por la plantas dependió de la adición de diferentes fuentes de nitrógeno y tratamientos. El consumo y contenido de nutrientes más alto del tallo fue obtenido cuando se trató con CM seguido por PR en todos los estadios de crecimiento, mientras que PR fue seguido por CM para semillas. Se ha encontrado que la recuperación del aceite responde a la adición de nitrógeno, pero los cambios en los ácidos grasos no fueron significativamente diferentes. Sin embargo la aplicación de fertilizantes orgánicos resultó en un incremento de los ácidos grasos insaturados

Hepatitis C virus as possible etiologic factor in idiopathic nephrotic syndrome among Egyptian patients

Hepatitis C virus (HCY) infection is associated with a variety of extrahepatic disorders. including cryoglobulinaernia and glomerulonephritis. Hepatitis C virus (HCV) glornerulopathy may be present as a primary glomerular disease. Our study included 50 adult Egyptian patients who were diagnosed as idiopathic nephrotic syndrome (NS). We described the clinical, pathological and immunological features of these patients. There was a high prevalence (50%) of HCV infection among these patients. The studied risk factors included history of; blood transfusion (16%) operation (24%) or antibilharzial drugs (76%). Hepatomegaly was observed in 24% of cases.Mernbranoproliferative glomerulonephritis (MPGN) was the commonest pathological  type associated with HCV (48%). Other patterns included focal segmental glomerulosclerosis (FSGS) in 32%, membranous in 8% and minimal change glomerulonephritis in 12%. Cryoglobulins were detected in 5.6% of 18 patients with HCV and idiopathic NS.Patients having HCV infection and membranoproliferative glomerulonephritis had hypocomplementemia and antinuclear antibodies were detected in 41.6%.Realising that HCV infection may be linked to different glomerulopathies, thus routine screening for HCV should be considered in serologic work-up of patients with glomerulopathy. Nevertheless, seroepiderniological studies including larger number of patients with glornerulopathy are therefore necessary to specify its relation with HCV infection

Biochemical composition and antioxidant properties of some seaweeds from Red Sea coast, Egypt

The current study investigated the biochemical composition and antioxidant properties of four seaweeds: Laurencia sp. (Rhodophyta), Cystoseira myrica, Hydroclathrus clathratus and Padina pavonica (Ochrophyta). The highest amount of carbohydrates was (215.78 mg/g dry wt.) in Laurencia sp. and proteins content was maximum (50 mg/g dry wt.) in Laurencia sp. and Cystoseira myrica. The highest values of free amino acid content were recorded in the brown seaweed species Cystoseira myrica (4.01 mg/g dry wt.). The pressurized hot water extract of Cystoseira myrica has the highest total phenolic content (1.61 mg GAE/g dry wt.). Cystoseira myrica contained the highest amounts of flavonoids (3.35 mg/g dry wt.), ascorbic acid (9.07 mg/g dry wt.) and α-tocopherol (27.25±0.00 abs. at 520 nm/g dry wt.). Furthermore, the ethyl alcohol extract of Cystoseira myrica showed high antioxidant capacities (541.6 mg/g dry wt.) and achieved the most powerful reducing ability among all of the different extracts of algal species. Statistical evaluation by Spearman correlation between the TAC assay and the total phenolic contents was found to be significant, but the correlation was nonsignificant between FRAP assay and the total phenolic contents. The composition of elements of the studied seaweed species was also analyzed. The most significant macro-elements present in the studied seaweeds were K, Na and Ca, representing that the seaweeds are good sources of these elements. Since, these seaweeds are widespread in the Egyptian waters, their biochemical composition and antioxidant capacities made them promising candidates for industrial, nutritional and pharmaceutical applications. DOI: http://dx.doi.org/10.5281/zenodo.147886

A SHALLOW NEURAL NETWORK MODEL FOR URBAN LAND COVER CLASSIFICATION USING VHR SATELLITE IMAGE FEATURES

Recently, image classification techniques using neural networks have received considerable attention in sustainable urban development, since their applications have an extreme effect on building distribution, infrastructural networks, and water resource management. In this research, a back-propagation shallow neural network model is presented for very high resolution satellite image classification in urban environments. Workflow procedures consider selecting and collecting data, preparing required study areas, extracting distinctive features, and applying the classification process. Visual interpretation is performed to identify observed land cover classes and detect distinctive features in the urban environment. Pre-processing techniques are implemented to present the used images in a more suited form for the classification techniques. A shallow neural network model (supported by MathWorks MATLAB environment) is successfully applied and results are evaluated. The proposed model is tested for classifying both WorldView-2 and WorldView-3 multispectral images with different spatial and spectral characteristics to check the model’s applicability to various kinds of satellite imagery and different study areas. Model outcomes are compared to two well-known classification methods; the Nearest Neighbour object-based method and the Maximum Likelihood pixel-based classifier, to validate and check the model stability. The overall accuracy achieved by the proposed model is 86.25% and 83.25%, while the nearest neighbour approach has obtained 84.50% and 82.75%, and the maximum likelihood classifier has accomplished 82.50% and 80.25% for study area 1 and study area 2 respectively. Obtained results indicate that the developed shallow neural network model achieves a promising accuracy for urban land cover classification in comparison with the standard techniques

Fatigue loading characteristic for the composite steel-concrete beams

During the past few decades, composite beams (steel I beam and concrete slab) have had a wide range of uses, particularly in bridge construction. This is due to its relatively low economic cost compared to individual steel structures or reinforced concrete structures. This type of bridges in particular and many similar industrial structures in general are repeatedly subjected to fatigue loads, and that is frequently, as a result of the vehicles passing on these bridges or the vibrations caused by the machines in the industrial facilities. It has been observed during the successive studies that they have been interested in studying this problem that it is concerned with the external structural behavior of these beams  such as a load –deflection relation, observing the cracks appearing during the failure stage and the strain in the steel and concrete flanges. Hence, in this study we have focused on several factors affecting mode of failure of these beams under the fatigue loads, and the common element in all stages of failure was the shear stud, specifically the welding collar at the base of this stud as it is a structurally weak region