Faculty’s Experiences Teaching English Language Learners in Higher Education

Conducted in a large size four-year state university, the purpose of this qualitative study was to learn how faculty of multiple disciplines examined and made meaning of their instructional practices and decisions when teaching ELL students, how they modified their instruction to meet the needs of ELLs, and what they saw as areas of struggle when working with this student population. Critical pedagogy (Freire, 1970) was used as a theoretical framework to further investigate the complex nature of how higher education faculty make meaning of their instructional experiences when teaching ELLs within the hierarchical structures inherent in higher education and society at large. Hence, the analyses and discussions were structured through the lens of a Freirean critical pedagogy which allowed me to reveal the complexity of higher education faculty’s teaching experiences when teaching ELLs and how their instructional decisions are rooted within these hierarchal institutional structures. The findings revealed that all participant faculty were genuinely empathetic towards their ELL students’ level of English proficiency and how it affected their learning outcomes, and they all expressed interest in attempting to modify their instruction to meet the needs of these students. However, they reported real concerns and frustrations due to their lack of knowledge, expertise, adequate preparation, and especially institutional support to address such needs. The prospect of having to attend to yet another task, in addition to already existing responsibilities, created tension and exacerbated already existing challenges, as faculty attempted to navigate their teaching load and academic obligations while attending to their ELL students’ linguistic needs as a catalyst for their learning outcomes and academic success

Simple modeling of self-oscillation in Nano-electro-mechanical systems

We present here a simple analytical model for self-oscillations in nano-electro-mechanical systems. We show that a field emission self-oscillator can be described by a lumped electrical circuit and that this approach is generalizable to other electromechanical oscillator devices. The analytical model is supported by dynamical simulations where the electrostatic parameters are obtained by finite element computations.Comment: accepted in AP

Characterization of Streptomyces strain SLO-105 isolated from Lake Oubeira sediments in North-East of Algeria

A microbial strain, SLO-105, isolated from Lake Oubeira sediment was screened for its antimicrobial activity against pathogenic bacteria and fungi. The strain showed broad-spectrum antibacterial activity against Gram-positive bacteria Staphylococcus aureus MRSA, Bacillus subtilus, Micrococcus leutus,Streptococcus fecalis and fungi Aspergillus niger and Rodotorulla mucilaginosa. However, no activity of the strain was observed against Gram negative bacteria Escherichia coli and Pseudomonas aeruginosa as well as on fungi Candida albicans. Analysis of 16S rDNA sequence and themorphological and physiological characteristics of the strain suggested that the isolate belonged to Streptomyces genus

Sensing and cooling of a nanomechanical resonator with an electron beam stimulated internal feedback and a capacitive force

A model for the cooling properties of a nanocantilever by a free electron beam is presented for a capacitive interaction. The optimal parameters for position sensing and cooling applications are estimated from previous experimental conditions. In particular , we demonstrate that a purely capacitive force and an electron beam stimulated internal feedback can lower the temperature of a nanocantilever by several orders of magnitude in striking contrast with the conventional electrostatic damping regime. We propose a step by step protocol to extract the interdependent parameters of the experiments. This work will aid future developments of ultra sensitive force sensors in electron microscopes

Utilizing Steel Slag in the Removal of Suspended Solids from Dewatered Construction Water

Construction dewatering is an operation used to remove shallow groundwater that infiltrates construction sites. After recovering this water from the construction sites, the water is either discharged to the sea, injected in deep groundwater aquifers, or treated and reused in some other applications. However, municipal and industrial application of this water is unfeasible due to its poor quality. Thus, in this study, dewatered construction water is being treated utilizing waste steel slag in order to improve the quality of the water. The pH of the dewatered construction water used for this study was 7.59 and the average diameter of steel slag used was 425 nm. For coagulation, the impact of the mass of steel slag and the contact time on the quality of dewatered construction water were studied. By using 5gm/L of steel slag, more than 85% of the total suspended solids and turbidity were removed within 30 minutes.The authors would like to thank Qatar University for the financial support. In addition, the authors would like to thank Qatar Steel for the supply of the steel slag sample

Trace element contamination in the mine-affected stream sediments of Oued Rarai in north-western Tunisia. A river basin scale assessment

High-quality and accurate environmental investigations are essential for the evaluation of contamination and subsequent decision-making processes. A combination of environmental geochemical indices, multivariate analyses and geographic information system approach was successfully used to assess contamination status and source apportionment of trace elements (Ag, As, Cd, Cr, Cu, Hg, Ni, Pb, Sb, V and Zn) in surface stream sediments from the Oued Rarai basin in north-western Tunisia, containing various metal and metalloid ores. The contamination level reported in this study indicates a non-negligible potential ecological risk, mainly related to sediment transport along the river. Antimony (concentrations ranged from 0.02 to 297 mg kg−1 and Igeo > 5), arsenic (from 0.5 to 1490 mg kg−1 and Igeo > 5), lead (from 2.9 to 5150 mg kg−1 and Igeo > 5) mercury (from 0.05 to 54.4 mg kg−1 and Igeo > 5) and silver (from 0.05 to 9.4 mg kg−1 and Igeo > 5) showed the most crucial contamination. Besides, potential ecological risk index values were maximum for arsenic with a median of 302, indicating a very high to serious ecological risk (> 160). Results from correlation analysis and principal component analysis revealed three main geochemical associations related to lithologic, tectonic and anthropogenic sources. V, Cr and Cu mainly originated from natural bedrock and soil. Ag and Cd were more controlled by both natural and mining enrichments. Mercury and Pb were mostly influenced by the ancient ore-related activities at the Oued Rarai site and north-east–south-west trending faults. Finally, Sb, As, Ni and Zn were largely controlled by the siliciclastic continental Neogene sequences. Finally, the physical and chemical dynamics of the watershed system, lithological properties, mineralisation, tectonic settings and mobilisation of subsurface sediments largely controlled both concentrations and spatial patterns of trace elements in the study basin. These results need to be considered in the strategies of suitable environmental management at former and current mining sites in north-western Tunisia

Invariant vector fields and the prolongation method for supersymmetric quantum systems

The kinematical and dynamical symmetries of equations describing the time evolution of quantum systems like the supersymmetric harmonic oscillator in one space dimension and the interaction of a non-relativistic spin one-half particle in a constant magnetic field are reviewed from the point of view of the vector field prolongation method. Generators of supersymmetries are then introduced so that we get Lie superalgebras of symmetries and supersymmetries. This approach does not require the introduction of Grassmann valued differential equations but a specific matrix realization and the concept of dynamical symmetry. The Jaynes-Cummings model and supersymmetric generalizations are then studied. We show how it is closely related to the preceding models. Lie algebras of symmetries and supersymmetries are also obtained.Comment: 37 pages, 7 table

High-level cefotaxime-resistant Proteus mirabilis strain isolated from a Tunisian intensive care unit ward: CTX-M-8 extended-spectrum β-lactamase coproduced with a plasmid mediated AmpC lactamase

The aimed of this study was to determine the implication of the biochemical and the molecular mechanism and to describe the properties of an extended-spectrum β-lactamase (ESBL) CTX-M-8 which was reported for the first time in Africa. A clinical isolate of Proteus mirabilis FS6449 was isolated from a patient hospitalized at an intensive care unit of the Military Hospital in Tunisia in 2009. Antimicrobial susceptibility was determined with the disk diffusion method according to Clinical and Laboratory Standards Institute (CLSI) guidelines and revealed that this strain was resistant to expanded-spectrum β-lactams. Analysis of P. mirabilis FS6449 by double-disk synergy test yielded a positive result suggesting the production of ESBLs. Sonicate of the isolate hydrolysed cefotaxime and benzylpenicillin. Isoelectric focusing exhibited four β-lactamase bands of isoelectric points (pIs) 5.6, 6, 6.5 and over 7.6. Polymerase chain reaction (PCR) and sequencing experiments revealed the presence of four β-lactamase genes encoding TEM-2, CTX-M-8, TEM-24, and an AmpC enzyme. Among them, the genes encoding TEM-24 and an AmpC enzyme were transferred to the recipient by conjugation experiments.Keywords: Resistance, β-lactamase, Proteus mirabilisAfrican Journal of Biotechnology Vol. 12(21), pp. 3278-328

‘Pole Test’ Measurements in Critical Leg Ischaemia

AbstractBackgroundFor the quantification of critical limb ischaemia (CLI) most vascular surgery units use sphygmo-manometric and transcutaneous oxygen pressure (TcPO2) measurements. However, measurements obtained by cuff-manometry can be overestimated especially in diabetic patients because of medial calcification that makes leg arteries less compressible. TcPO2 measurements present a considerable overlap in the values obtained for patients with different degrees of ischaemia and its reproducibility has been questioned. Arterial wall stiffness has less influence on the pole test, based on hydrostatic pressure derived by leg elevation, and this test seems to provide a reliable index of CLI.ObjectiveThe objective of this study was to evaluate the pole pressure test for detection of critical lower limb ischaemia, correlating results with cuff-manometry and transcutaneous oxygen pressure.DesignUniversity hospital-prospective study.Materials and methodsSeventy-four patients (83 legs) with rest pain or gangrene were evaluated by four methods: pole test, cuff-manometry, TcPO2 and arteriography. CLI was present if the following criteria were met: (a) important arteriographic lesions+rest pain with an ankle systolic pressure (ASP) ≤40mmHg and/or a TcPO2 ≤30mmHg, or (b) important arteriographic lesions+tissue loss with an ASP ≤60mmHg and/or a TcPO2 ≤40mmHg. Fifty-seven lower limbs met the criteria for CLI.ResultsMeasurements obtained by cuff-manometry were significantly higher to those obtained by pole test (mean pressure difference: 40mmHg, p<0.001). The difference between the two methods remained statistically significant for both diabetics (50.73, p<0.001) and non-diabetics (31.46, p<0.001). Mean TcPO2 value was 15.51mmHg and there was no important difference between patients with and without diabetes. Overall, there was a correlation between sphygmomanometry and pole test (r=0.481). The correlation persisted for patients without diabetes (r=0.581), but was not evident in patients with diabetes. Correlation between pole test and TcPO2 was observed only for patients with diabetes (r=0.444). There was no correlation between cuff-manometry and TcPO2. The pole test offered an accuracy of 88% for the detection of CLI. The sensitivity of this test was 95% and the specificity 73%

Métodos alternativos de muestreo para estimar la estructura y caracteres reproductivos de bosques

Aleppo pine had a large forest cover in North Africa and along the Mediterranean basin which management is not fully developed and new forest tools are required. In this research, the forest structure, epidometric characteristics and allometric relationships were studied in 79 plots covering four bioclimatic zones from natural even aged forests of Aleppo pine located between eastern Algeria to the western coastal part of Tunisia. To characterize the forest structure three sampling methods were carried out: classical inventories (recording all pine trees), and two simplified approach using one average size or five dominant pine tree per plot. Annual growth increment and cone production were only calculated for the average size tree. Furthermore, the analysis of variance showed non-significant differences recorded between bioclimatic zones in trunk or crown diameter using the two simplified approach. Moreover, a significant decrease from wetter to drier areas in total height, crown height, cone seed production was observed only for average size tree method. However, the analysis of covariance showed significant differences between both approaches in total height, trunk diameter and crown coverage which were largely influenced by the pine tree density. In future investigations, we confirmed previous research that the dominant tree is a good sampling method to examine the site fertility, whereas the average size tree constitutes a valuable approach to study the population growth and reproduction.El pino carrasco muestra una gran cobertura forestal, tanto en el norte de África como en toda la Cuenca Mediterránea, cuyo manejo no está totalmente desarrollado lo que requiere nuevas herramientas de manejo. En esta investigación, se estudiaron la estructura forestal, las características epidométricas y las relaciones alométricas de 79 parcelas distribuidas a lo largo de cuatro zonas bioclimáticas en bosques regulares de pino carrasco situados entre el este de Argelia y la costa este de Túnez. Para caracterizar la estructura forestal se aplicaron tres métodos de muestreo: inventario clásico (midiendo todos los pies) y dos propuestas más sencillas, usando un árbol medio o cinco pies dominantes por parcela. El análisis de varianza no mostraba diferencias significativas de las mediciones de diámetro de tronco y de copa realizadas entre las distintas zonas bioclimáticas usando ambos métodos. Por otra parte, se observó una disminución significativa de las zonas más húmedas a las más secas en altura toral, altura de copa y producción de semillas fue observada aplicando el método de árbol medio. Además, el análisis de covarianzas mostraba diferencias significativas, usando ambas metodologías, en los valores medios de altura total, diámetro de tronco y cobertura de copa que mostraron estar influenciados por los valores de la densidad de arbolado de cada zona. Para futuras investigaciones, confirmamos estudios previos que apuntaban que la propuesta de muestreo de árboles dominantes como un buen método de muestreo para caracterizar la calidad de sitio mientras que la de árbol medio constituye una valiosa propuesta para el estudio del crecimiento de poblaciones y sus características reproductivas