A least squares solution to regionalize VTEC estimates for positioning applications

A new approach is presented to improve the spatial and temporal resolution of the Vertical Total Electron Content (VTEC) estimates for regional positioning applications. The proposed technique utilises a priori information from the Global Ionosphere Maps (GIMs) of the Center for Orbit Determination in Europe (CODE), provided in terms of Spherical Harmonic (SH) coefficients of up to degree and order 15. Then, it updates the VTEC estimates using a new set of base-functions (with better resolution than SHs) while using the measurements of a regional GNSS network. To achieve the highest accuracy possible, our implementation is based on a transformation of the GIM/CODE VTECs to their equivalent coefficients in terms of (spherical) Slepian functions. These functions are band-limited and reflect the majority of signal energy inside an arbitrarily defined region, yet their orthogonal property is remained. Then, new dual-frequency GNSS measurements are introduced to a Least Squares (LS) updating step that modifies the Slepian VTEC coefficients within the region of interest. Numerical application of this study is demonstrated using a synthetic example and ground-based GPS data in South America. The results are also validated against the VTEC estimations derived from independent GPS stations (that are not used in the modelling), and the VTEC products of international centres. Our results indicate that, by using 62 GPS stations in South America, the ionospheric delay estimation can be considerably improved. For example, using the new VTEC estimates in a Precise Point Positioning (PPP) experiment improved the positioning accuracy compared to the usage of GIM/CODE and Klobuchar models. The reductions in the root mean squared of errors were ∼23% and 25% for a day with moderate solar activity while 26% and ∼35% for a day with high solar activity, respectively

Química mineral y geotermobarometría de rocas gabroicas del área de Gysel, montañas de Alborz, Irán del norte

The gabbroic rocks in the Gysel area of the Central Alborz Mountains in north Iran are intruded into the Eocene Volcano-sedimentary units. The main gabbroic rocks varieties include gabbro porphyry, olivine gabbro, olivine dolerite and olivine monzo-gabbro. The main minerals phases in the rocks are plagioclase and pyroxene and the chief textures are sub-hedral granular, trachytoidic, porphyritic, intergranular and poikilitic. Electron microprobe analyses on minerals in the rock samples shows that plagioclase composition ranges from labradorite to bytonite, with oscillatory and normal chemical zonings. Clinopyroxene is augite and orthopyroxene is hypersthene to ferro-hypersthene. Thermometry calculations indicate temperatures of 650˚C to 750˚C for plagioclase crystallization and 950˚C to 1130˚C for pyroxene crystallization. Clinopyroxene chemistry reveals sub-alkaline and calc-alkaline nature for the parental magma emplaced in a volcanic arc setting.Las rocas gabroicas en el área de Gysel de las montañas Alborz Central en el norte de Irán se introducen en las unidades sedimentarias del volcán Eoceno. Las principales variedades de rocas gabroicas incluyen pórfido de gabro, gabro olivino, dolerita olivina y monzo-gabro olivino. Las principales fases minerales en las rocas son la plagioclasa y el piroxeno y las texturas principales son sub-hedral granular, trachytoidic, porfirita, intergranular y poikilitic. Los análisis de micro sonda electrónica sobre minerales en las muestras de roca muestran que la composición de plagioclasa varía de labradorita a bytonita, con zonificaciones químicas oscilatorias y normales. El clinopiroxeno es augita y el ortopiroxeno es hiperesteno a ferro-hiperesteno. Los cálculos de termometría indican temperaturas de 650 ° C a 750 ° C para la cristalización de plagioclasa y de 950 ° C a 1130 ° C para la cristalización de piroxeno. La química del clinopiroxeno revela la naturaleza subalcalina y calcálica alcalina para el magma parental emplazado en un entorno de arco volcánic

Química mineral y geotermobarometría de rocas gabroicas del área de Gysel, montañas de Alborz, Irán del norte

The gabbroic rocks in the Gysel area of the Central Alborz Mountains in north Iran are intruded into the Eocene Volcano-sedimentary units. The main gabbroic rocks varieties include gabbro porphyry, olivine gabbro, olivine dolerite and olivine monzo-gabbro. The main minerals phases in the rocks are plagioclase and pyroxene and the chief textures are sub-hedral granular, trachytoidic, porphyritic, intergranular and poikilitic. Electron microprobe analyses on minerals in the rock samples shows that plagioclase composition ranges from labradorite to bytonite, with oscillatory and normal chemical zonings. Clinopyroxene is augite and orthopyroxene is hypersthene to ferro-hypersthene. Thermometry calculations indicate temperatures of 650˚C to 750˚C for plagioclase crystallization and 950˚C to 1130˚C for pyroxene crystallization. Clinopyroxene chemistry reveals sub-alkaline and calc-alkaline nature for the parental magma emplaced in a volcanic arc setting.Las rocas gabroicas en el área de Gysel de las montañas Alborz Central en el norte de Irán se introducen en las unidades sedimentarias del volcán Eoceno. Las principales variedades de rocas gabroicas incluyen pórfido de gabro, gabro olivino, dolerita olivina y monzo-gabro olivino. Las principales fases minerales en las rocas son la plagioclasa y el piroxeno y las texturas principales son sub-hedral granular, trachytoidic, porfirita, intergranular y poikilitic. Los análisis de micro sonda electrónica sobre minerales en las muestras de roca muestran que la composición de plagioclasa varía de labradorita a bytonita, con zonificaciones químicas oscilatorias y normales. El clinopiroxeno es augita y el ortopiroxeno es hiperesteno a ferro-hiperesteno. Los cálculos de termometría indican temperaturas de 650 ° C a 750 ° C para la cristalización de plagioclasa y de 950 ° C a 1130 ° C para la cristalización de piroxeno. La química del clinopiroxeno revela la naturaleza subalcalina y calcálica alcalina para el magma parental emplazado en un entorno de arco volcánic

Antimicrobial Activity of Calcium-Enriched Mixture Cement and Biodentine on Enterococcus faecalis: An in Vitro Study

Introduction: The main cause of endodontic failure is residual bacteria in the root canal system. Enterococcus faecalis (E. faecalis) is the predominant species isolated from infected root canals. This study aims to compare the antibacterial activity of calcium-enriched mixture (CEM) cement and Biodentine as root canal filling materials on E. faecalis. Methods and Materials: Seventy extracted human single-rooted teeth were prepared and infected with E. faecalis for 24 h. Specimens were randomly divided into control or experimental groups; the later were filled with either CEM cement or Biodentine. Dentinal samples were collected after 7 and 30 days and transferred to test tubes. After incubation, the number of colony forming units (CFUs) were counted and analyzed using the Kruskal-Wallis test, followed by the Mann Whitney U test. The level of significance was set at 0.05. Results: The reduction in mean CFU level of E. faecalis was significantly more in the presence of CEM cement at both time intervals (P<0.001). Compared to the positive control, Biodentine significantly reduced the mean CFU level only after 30 days (P<0.01). Conclusion: Although both biomaterials exerted antibacterial activity against E. faecalis, the CEM cement had more antibacterial activity than Biodentine.Keywords: Antibacterial Agent; Biodentine; Calcium-Enriched Mixture Cement; CEM Cement; Endodontics

Effects of Social Media on People’s Tendency Toward Aesthetic Dental Treatments

Objectives This study aimed to investigate the impact of social media on people’s tendency toward aesthetic dental treatments in Iran. Methods This cross-sectional study was performed on 410 individuals, including dentists or dental students and laypeople, who were selected via convenience sampling. A questionnaire, consisting of sociodemographic characteristics, frequency of social media use, tendency toward aesthetic dental treatments, and factors affecting people’s decisions, was completed for data collection. This online questionnaire was created using the Porsline© website and posted on social media. The collected data were analyzed in SPSS version 21, using Chi-square test. A P-value less than 0.05 was considered statistically significant. Results Of 410 participants, 157 (38.3%) were dentists or dental students. Only 38.2% of the participants in the dentist group were willing to receive aesthetic dental treatments, whereas laypeople were significantly more inclined to receive such treatments (69.2%) (P<0.001). Almost half of people who used social media platforms several times a day and also 71.8% of people who used social media once a day or less showed tendency toward aesthetic dental treatments (P=0.01). Conclusion Based on the results, the time spent on social media was not significantly associated with people's tendency to receive aesthetic dental treatments. Also, dentists were less interested in such treatments for themselves

Reconstructing regional ionospheric electron density: a combined spherical slepian function and empirical orthogonal function approach

The computerized ionospheric tomography is a method for imaging the Earth’s ionosphere using a sounding technique and computing the slant total electron content (STEC) values from data of the global positioning system (GPS). The most common approach for ionospheric tomography is the voxel-based model, in which (1) the ionosphere is divided into voxels, (2) the STEC is then measured along (many) satellite signal paths, and finally (3) an inversion procedure is applied to reconstruct the electron density distribution of the ionosphere. In this study, a computationally efficient approach is introduced, which improves the inversion procedure of step 3. Our proposed method combines the empirical orthogonal function and the spherical Slepian base functions to describe the vertical and horizontal distribution of electron density, respectively. Thus, it can be applied on regional and global case studies. Numerical application is demonstrated using the ground-based GPS data over South America. Our results are validated against ionospheric tomography obtained from the constellation observing system for meteorology, ionosphere, and climate (COSMIC) observations and the global ionosphere map estimated by international centers, as well as by comparison with STEC derived from independent GPS stations. Using the proposed approach, we find that while using 30 GPS measurements in South America, one can achieve comparable accuracy with those from COSMIC data within the reported accuracy (1 × 1011 el/cm3) of the product. Comparisons with real observations of two GPS stations indicate an absolute difference is less than 2 TECU (where 1 total electron content unit, TECU, is 1016 electrons/m2)

1H NMR-based metabolomics approach to understanding the temperature-dependent pathogenicity of Lactococcus garvieae

Lactococcus garvieae is known as main agent of the bacterial diseases, Lactococcosis in trout farms. The present study was aimed to study the metabolic bases of the temperature-dependent pathogenicity of the L. garvieae using 1H NMR spectroscopy. The bacteria were grown at different temperatures, including 10, 14, 18 and 22˚C and then the metabolites extracted, identified and quantified. The results of PLS-DA analysis clearly separated the experimental treatments. The main metabolites responsible for this separation were acetate, acetoacetate, creatine phosphate, succinylacetone and trehalose. Furthermore, the result of the analysis of variance indicated also significant differences in metabolome content between temperature treatments. The bacteria exposed to higher temperatures showed more concentration of acetate and acetoacetate compared to those grown at 10°C. The concentrations of trehalose were higher in the bacteria grown at 14 and 18°C compared to other temperature treatments. The higher levels of succinylacetone were found in the bacteria exposed to the temperature less than 14°C compared to those grown at 18 and 22°C. The creatine phosphate concentrations increased with temperature, however, a significant decline occurred at 22°C. The levels of isoeugenol, methionine and betaine significantly declined with increase of temperature from 10 to 22°C. Also, the concentration of N-Acetylglutamine significantly raised as the temperature increased from 10 to 22°C. In conclusion, the temperature altered the metabolome of L. garvie, which this may be linked to the pathogenicity. The temperature probably affects fermentation, homeostasis, energetic condition and metabolism of amino acids in L. garvieae

THE MONEY DEMAND FUNCTIONS IN ISLAMIC ECONOMY: NEW EVIDENCE FROM IRAN-ARDL APPROACH

The demand for money is one of the most fundamental issues of the monetary economy for policy decision. On the other hand, according to the principle of prohibition of Riba, attitudes about the money market conditions in Islamic economics, is quite different from conventional economics. Hence achieving the money demand function in an Islamic country would be necessary. Most studies about the money demand in Islamic economy used the Keynesian approach, while in modern macroeconomics, money demand function derived by using the microeconomics-based approach. Hence in this article investigate some models of the microeconomics-based approach, then, in accordance with Islamic principles, it choose the best among them that is shopping-time model. After that we derive the Islamic money demand function. The results indicate that the demand for money is the function of income and rental rates of sukuk. The marginal product of capital due to an additional unit of income spend for Infaq (spending in Allah's way), depend on the expected inflation rate, depreciation rate and rental rates of Sukuk. In this paper, apply ARDL approach to estimate the money demand function in Islamic republic of Iran in period of 1978-2008 i.e. after Islamic revolution. The results suggested that M1 and M2 money demand are co-integrated with income and rental rate of Sukuk. Incorporating CUSUM and CUSUMSQ tests into co-integration analysis, we conclude that M2 money demand is more stable than M1

Studying the Relationship between Factors related to Stress and Stress Management of Insurance Employees of Iran Social Security Organization

Introduction & Purpose: Considering the stressors in the Social Security Organization and the management of these factors in order to improve efficiency and quality of medical services, the present study aimed to to provide a stress management model for insurance employees of the Social Security Organization of Iran. Materials and Methods: This research is applied in purpose and is survey in method. The statistical population consisted of three groups: Experts familiar with the field of employee stress management that by selective non-random sampling method, 15 individuals were selected. Results: All employees and managers of the Social Security Organization of Iran that 462 were selected based on the Cochran's formula, and 232 people were selected by stratified random sampling method appropriate to the size of the population. In this study, a questionnaire was used to collect the required data. The model design and approval questionnaire with 29 components and indicators was changed to 24 items after obtaining the opinion of experts using the Delphi method. The Stress-Related Factors Questionnaire included 72 questions and the Stress Management Questionnaire consisted of 24 questions. In this study, the content validity of the questionnaire of factors related to stress and stress management were 0.915 and 0.921 respectively, and their reliability was calculated to be 99.1 and 94.6, which was greater than 0.7 and it was acceptable. Data analysis was performed using structural equation modeling with Lisrel software. Discussion: At 5% level error between individual factors (-0.33), occupational factors (-0.37), managerial factors (-5.99), organizational factors (-4.62), environmental factors (0.76 0), there was a significant and inverse relationship between stress and stress management of insurance employees of the Social Security Organization of Iran. Conclusion: The existing facts in the discussion of psychopathology and mental health in the workplace show that a significant percentage of the causes of mental illness and work fatigue among the employees of organizations can be found in the behavior methods and personality of managers