1,257 research outputs found
Evaluation the Effects of Waste Glass Powder Mixed with Hydrated Lime on the Unconfined Compressive Strength of Clayey Soil
Stabilization of clayey soil is commonly used to enhance unfavorable engineering properties. The effects of silica additives on soil improvement have been considered recently, and documented research studies on the characteristics of problematic clays stabilized by silica additives are interesting for many researchers. Alternative waste disposal strategies that would be both economically beneficial and environmentally friendly have been identified by this study. In the present study, waste silica-based addition is used to stabilize clayey soil, and the time-dependent changes in strength properties are investigated. Unconfined compressive strength (UCS) tests were conducted on stabilized samples at various curing durations to investigate macro-level properties. The UCS test results revealed that the 7.5% of GP+ 5% L content was optimal for the clayey soil as the strength was increased by 166.06%. The addition of the glass powder with hydrated lime components to the clayey soil resulted in stabilized samples, indicating a dense and compact matrix and reduced soil porosity, which increased the mechanical strength, according to the SEM analysis. This curing reaction technique is very beneficial and economical for geotechnical engineering applications
On the Differential Geometry of
The differential calculus on the quantum supergroup GL was
introduced by Schmidke {\it et al}. (1990 {\it Z. Phys. C} {\bf 48} 249). We
construct a differential calculus on the quantum supergroup GL in a
different way and we obtain its quantum superalgebra. The main structures are
derived without an R-matrix. It is seen that the found results can be written
with help of a matrix Comment: 14 page
Aberrant right subclavian artery in a cadaver: a case report of an aortic arch anomaly
In early embryogenesis, aortic anomalies occur as a consequence of disorders in the development of the primitive aortic arches system. Aberrant right subclavian artery, also known as arteria lusoria, is one of the important congenital anomalies of the aortic arch, in which the right subclavian artery arises from the arch of aorta instead of the brachiocephalic trunk. During routine dissection of a female cadaver, we observed retro-oesophageal aberrant right subclavian artery arising as the fourth branch from the aortic arch. In this case, the brachiocephalic trunk was absent. Early detection of aortic arch anomalies through diagnostic interventions is helpful to avoid complications during surgical procedures
ISOLATION AND IDENTIFICATION OF BIOFILM PRODUCING ENTEROCOCCUS FAECALIS FROM ROOT CANAL
This study was aimed to one of the most prevalent causes for endodontic treatment failure is the presence of Enterococcus faecalis bacterium within teeth root canals. To achieve successful treatment, it is so important to study E. faecalis behavior. The aim of study was to investigate biofilm production and antibiotic sensitivity of E. faecalis isolated from root canals. Results showed isolation of E. feacalis (65%) of samples, identified by specific gene by PCR technique. Most isolates were sensitive to Imipenem and resistant to Erythromycin, Clindamycin, Tetracycline and Trimethoprim. Strong biofilm production was detected among 29.5% of highest antibiotic resistant isolates. The results may indicate that infected root canals with E. feacalis may lead to serious complication for patients
Variétés Chifaa et Bounejmate : Caractérisation et Etude de leur effet sur la structure alvéolaire du pain par analyse d’image numérique
The alveolar structure of bread products is one of the factors that the bakery industry seeks to control. The objective of this work is to elucidate the effect of this parameter through the evaluation of the alveolar structure of bread by image analysis. The naked barley variety "Chifaà " and the naked oat variety "Bounejmate" were used for this purpose. The work consists on the characterisation of the physical and chemical criteria regarding these two varieties followed by the constitution of mixtures from a commercial flour of soft wheat and complete flours of barley and oat, respectively, as follows: (100% wheat), (barley or oats/wheat) : (10/90), (20/80) and (30/70). Seven loaves of bread (6 mixed loaves and the control loaf) were made using a bread machine. Slices of the obtained loaves were then analysed by image analysis for the following criteria (crumb development, total area of the alveoli, % alveoli in the crumb, number of alveoli). The results showed variability in the composition of the studied varieties. The variety "Chifaà " is marked by a high content of β-glucan (7.9%) and the variety "Bounejmate" is marked by a high content of protein (17.6%) and fat (10.4%). The addition of oat induced a 44.7% decrease in crumb development from 10% addition, whereas barley showed a similar effect at 30% addition. Moreover, barley at 30% addition had more negative effect on the crumb alveoli which decrease until disappearance of the majority.La structure alvéolaire des produits de panification constitue un des facteurs que la profession cherche à maitriser. L’objectif de ce travail est d’élucider l’effet de cet ajout à travers l’évaluation de la structure alvéolaire du pain par analyse d’image. La variété d’orge à grains nus « Chifaa » et la variété d’avoine à grains nus « Bounejmate » ont été utilisées à cet effet. Le travail consiste à une caractérisation des critères physico-chimiques des deux variétés suivi de la constitution des mélanges à partir d’une farine commerciale de blé tendre et des farines complètes d’orge et d’avoine, respectivement, comme suit ; (100% blé), (orge ou avoine/blé) : (10/90), (20/80) et (30/70). Sept pains (6 pains mélanges et le pain contrôle) ont été fabriqués à l’aide d’une machine à pain. Des tranches des pains obtenus ont subies par la suite une analyse d’image pour les critères suivants (développement de la mie, aire total des alvéoles, % d’alvéoles dans la mie, nombre d’alvéoles). Les résultats ont montré une variabilité dans la composition des variétés utilisées, en effet la variété « Chifaa» est marquée par une forte teneur en β-glucane (7,9%) et la variété « Bounejmate » est marquée par une forte teneur en protéine (17,6%) et en lipides (10,4%). L’ajout d’avoine a induit une diminution de 44.7% du développement de la mie à partir de 10% d’ajout alors que l’orge n’a montré un effet similaire qu’à partir de 30% d’ajout. En outre, l’orge à 30% d’ajout a montré plus d’effet négatif sur les alvéoles de la mie qui diminuent jusqu’à disparition de la majorité
Brain age estimation at tract group level and its association with daily life measures, cardiac risk factors and genetic variants
Abstract Brain age can be estimated using different Magnetic Resonance Imaging (MRI) modalities including diffusion MRI. Recent studies demonstrated that white matter (WM) tracts that share the same function might experience similar alterations. Therefore, in this work, we sought to investigate such issue focusing on five WM bundles holding that feature that is Association, Brainstem, Commissural, Limbic and Projection fibers, respectively. For each tract group, we estimated brain age for 15,335 healthy participants from United Kingdom Biobank relying on diffusion MRI data derived endophenotypes, Bayesian ridge regression modeling and 10 fold-cross validation. Furthermore, we estimated brain age for an Ensemble model that gathers all the considered WM bundles. Association analysis was subsequently performed between the estimated brain age delta as resulting from the six models, that is for each tract group as well as for the Ensemble model, and 38 daily life style measures, 14 cardiac risk factors and cardiovascular magnetic resonance imaging features and genetic variants. The Ensemble model that used all tracts from all fiber groups (FG) performed better than other models to estimate brain age. Limbic tracts based model reached the highest accuracy with a Mean Absolute Error (MAE) of 5.08, followed by the Commissural ( MAE = 5.23 ), Association ( MAE = 5.24 ), and Projection ( MAE = 5.28 ) ones. The Brainstem tracts based model was the less accurate achieving a MAE of 5.86. Accordingly, our study suggests that the Limbic tracts experience less brain aging or allows for more accurate estimates compared to other tract groups. Moreover, the results suggest that Limbic tract leads to the largest number of significant associations with daily lifestyle factors than the other tract groups. Lastly, two SNPs were significantly (p value < 5 E - 8 ) associated with brain age delta in the Projection fibers. Those SNPs are mapped to HIST1H1A and SLC17A3 genes
Brain age estimation at tract group level and its association with daily life measures, cardiac risk factors and genetic variants
Brain age can be estimated using different Magnetic Resonance Imaging (MRI) modalities including diffusion MRI. Recent studies demonstrated that white matter (WM) tracts that share the same function might experience similar alterations. Therefore, in this work, we sought to investigate such issue focusing on five WM bundles holding that feature that is Association, Brainstem, Commissural, Limbic and Projection fibers, respectively. For each tract group, we estimated brain age for 15,335 healthy participants from United Kingdom Biobank relying on diffusion MRI data derived endophenotypes, Bayesian ridge regression modeling and 10 fold-cross validation. Furthermore, we estimated brain age for an Ensemble model that gathers all the considered WM bundles. Association analysis was subsequently performed between the estimated brain age delta as resulting from the six models, that is for each tract group as well as for the Ensemble model, and 38 daily life style measures, 14 cardiac risk factors and cardiovascular magnetic resonance imaging features and genetic variants. The Ensemble model that used all tracts from all fiber groups (FG) performed better than other models to estimate brain age. Limbic tracts based model reached the highest accuracy with a Mean Absolute Error (MAE) of 5.08, followed by the Commissural ([Formula: see text]), Association ([Formula: see text]), and Projection ([Formula: see text]) ones. The Brainstem tracts based model was the less accurate achieving a MAE of 5.86. Accordingly, our study suggests that the Limbic tracts experience less brain aging or allows for more accurate estimates compared to other tract groups. Moreover, the results suggest that Limbic tract leads to the largest number of significant associations with daily lifestyle factors than the other tract groups. Lastly, two SNPs were significantly (p value [Formula: see text]) associated with brain age delta in the Projection fibers. Those SNPs are mapped to HIST1H1A and SLC17A3 genes
The African Political Business Cycle: Varieties of Experience
We seek to understand both the incidence and the impact of the African political business cycle in the light of a literature which has argued that, with major extensions of democracy since the 1990s, the cycle has both become more intense and has made African political systems more fragile. With the help of country-case studies, we argue, first, that the African political business cycle is not homogeneous, and occurs relatively infrequently in so-called ‘dominant-party systems’ where a pre-election stimulus confers little political advantage. Secondly, we show that, in those countries where a political cycle does occur, it does not necessarily cause institutional damage. Whether it does or not depends not so much on whether there is an electoral cycle as on whether this cycle calms or exacerbates fears of an unjust allocation of resources. In other words, the composition of the pre-election stimulus, in terms of its allocation between different categories of voter, is as important as its size
Microscopy of terahertz spoof surface plasmons propagating on planar metamaterial waveguides
Surface plasmon polaritons (SPPs) are electromagnetic waves that have attracted significant interest owing to their subwavelength confinement and the strong field enhancement that they provide. Yet in the terahertz (THz) frequency region of the spectrum, which is well below the plasma frequency of metals, these surface waves are characterized by extremely weak confinement that has severely limited their exploitation for information processing and sensing. One means to circumvent this limitation is through subwavelength structuring of a metallic surface, which can thereby be engineered to support the propagation of spoof surface plasmon polaritons (SSPPs) that closely mimic the properties of SPPs. In this work, we report the design and experimental characterization of an ultra-thin metamaterial planar waveguide that supports SSPPs at THz frequencies. Finite-element method simulations are shown to predict the excitation of SSPPs on the surface of our devices under free-space illumination at 3.45 THz. We investigate these structures experimentally using THz scattering-type scanning near-field microscopy (THz-s-SNOM) to map directly the out-of-plane electric field associated with the propagation of SSPPs on the surface of the waveguides. Our work paves the way for the future development of plasmonic integrated circuit technologies and components operating in the THz frequency band
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