Social and psychological challenges facing scholarship Saudi students studying in foreign countries

El estudio pretendía explorar y averiguar las razones de los retos psicológicos a los que se enfrentan los estudiantes becados saudíes que estudian en países extranjeros, así como los efectos de dichos retos. La muestra del estudio consistió en 1.446 estudiantes masculinos y femeninos del total de estudiantes saudíes en cada uno de los Estados Unidos, Reino Unido, Canadá y Australia (75.485). El investigador utilizó un enfoque analítico descriptivo para alcanzar los objetivos del estudio. Se preparó un cuestionario para explorar los retos sociales y psicológicos a los que se enfrentan las becas de los estudiantes saudíes que estudian en países extranjeros que constaba de (67) términos. Los resultados mostraron que había diferencias estadísticamente significativas en la dimensión de apoyo social y psicológico durante los tres primeros meses de beca y en la dimensión de identidad y pertenencia al grupo étnico, así como en la puntuación global del cuestionario de retos psicológicos y sociales, en función de la variable género, y la diferencia era a favor de los varones. La primera pregunta exploró los principales retos psicológicos y sociales de los estudiantes becarios saudíes que participan en un programa de estudios en el extranjero. Hay un claro reconocimiento de los cambios culturales de la cultura de acogida y la original desde el principio. Tomando la estancia en su conjunto (más allá de los tres primeros meses) el principal interés tiene que ver con la integración o conciliación de la visión de la vida que tienen en la nueva cultura con la suya propia. Hay un sentimiento de orgullo y satisfacción en relación con la cultura de origen que, como resultado, proporciona un firme sentido de identidad étnica/cultural. Al final del programa, los estudiantes destacaron la importancia de preparar programas específicos para ayudar a los estudiantes a adaptarse a la cultura de acogida, especificando los posibles problemas que pueden surgir probablemente en los tres primeros meses. Descubrimos que las mujeres se adaptaban peor que los hombres, y que también tenían puntuaciones más bajas de actitud positiva hacia la nueva cultura. Los estudiantes con un alto nivel de inglés experimentaron más estrés, probablemente porque estaban más expuestos a la cultura de acogida, en comparación con los que tenían un menor dominio del idioma. En cuanto a la variable de las condiciones de vivienda se corrobora que el patrón de integración de la aculturación implica mayores niveles de estrés. Aquellos estudiantes que vivían de forma privada interactuaban más con la cultura de origen y aunque presentaban actitudes más positivas hacia la cultura de acogida, también presentaban mayores niveles de malestar identitario. Aquellos estudiantes que vivían con sus familias o con familias de acogida (que generan un contexto con mayor seguridad y confort) tenían entonces peores actitudes hacia la cultura de acogida y mayores niveles de exploración étnica y afirmación de la propia cultura de origen. La calidad de la adaptación cultural de los estudiantes no puede entenderse sin tener en cuenta el momento de la estancia. Al final del programa se reactiva el sentido de identidad étnica en todos los estudiantes, como posible preparación para el regreso a la cultura de origen. Por el contrario, los valores de exploración de la propia cultura son mayores al principio, como forma de reafirmación ante los retos de la nueva cultura. Apoyamos la importancia de una estrategia de aculturación integradora para promover la adaptación, la transición, la satisfacción y la finalización con éxito de un programa internacional. Sin embargo, las estrategias de separación son igualmente comunes y suelen tener lugar al principio y al final del programa de estancia

Thermal analysis of submicron nanocrystalline diamond films

The thermal properties of sub-μm nanocrystalline diamond films in the range of 0.37–1.1 μm grown by hot filament CVD, initiated by bias enhanced nucleation on a nm-thin Si-nucleation layer on various substrates, have been characterized by scanning thermal microscopy. After coalescence, the films have been outgrown with a columnar grain structure. The results indicate that even in the sub-μm range, the average thermal conductivity of these NCD films approaches 400 W m− 1 K− 1. By patterning the films into membranes and step-like mesas, the lateral component and the vertical component of the thermal conductivity, k<sub>lateral</sub> and k<sub>vertical</sub>, have been isolated showing an anisotropy between vertical conduction along the columns, with k<sub>vertical</sub> ≈ 1000 W m− 1 K− 1, and a weaker lateral conduction across the columns, with k<sub>lateral</sub> ≈ 300 W m− 1 K− 1

Selecting the number and values of the CPWI steering angles and the effect of that on imaging quality

Compounded Plane-Wave Imaging (CPWI) has the ability to provide ultrafast imaging for many applications like colour flow imaging, microbubble imaging and elastography. The compounding operation improves the imaging quality at the expense of reducing the frame rate. Due to the importance of frame rate in ultrafast imaging, selecting the number and value of the compounded angles is a critical step to achieve the best possible imaging quality using the minimum number of angles whilst preserving the frame rate. This paper produces a new method for selecting the angular range and the number of angles in CPWI depending on the characteristics of the transducer and medium using Field II program. Experiments were performed on a wire phantom to show the efficiency of the produced method. The results show a comparative imaging quality of CPWI at the selected parameters when compared with linear imaging

Two-way Quality Assessment Approach for Tumour Detection using Free-hand Strain Imaging

A novel two-way image quality assessment method is proposed for free-hand strain imaging. In elasticity imaging, tissue with different stiffness exhibit varying contrast in the strain images and detectability of a lesion is measured using elastographic contrast-to-noise ratio (CNRe). Representing quality of strain images quantitatively is vital for improving imaging techniques and also for clinical diagnosis. It avoids the subjective approach of interpreting strain images. Conventionally, contrast between stiff lesion and surrounding soft tissue is measured using contrast-to-noise ratio and strain image with the highest CNRe amplitude is considered an optimal strain image. However experimental results have suggested that merely CNRe metric is often misleading and does not always represent the true elastic modulus contrast as the correlation coefficient falls below an acceptable levels and accuracy is compromised. Therefore in this study, the objective is to propose a comprehensive strain image quality assessment method which is reliable for clinical examinations and research

Mercer–Trapezoid Rule for the Riemann–Stieltjes Integral with Applications

In this paper several new error bounds for the Mercer - Trapezoid quadrature rule for the Riemann-Stieltjes integral under various assumptions are proved. Applications for functions of selfadjoint operators on complex Hilbert spaces are provided as well

Comparison of Spatial and Temporal Averaging on Ultrafast Imaging in Presence of Quantization Errors

In compound plane wave imaging (CPWI), multiple plane waves are used to insonify the imaging region with different steering angles. The compounding operation is effectively a spatial averaging filter that reduces the speckles of the image and increases the image contrast and its lateral resolution. Although spatial averaging often improves CPWI image quality, quantization errors which dependent on sampling frequency and element spacing (pitch), introduced during beam steering reduce this improvement. In this study, the effect of spatial and temporal averaging on speckle noise reduction, contrast resolution and spatial resolution in ultrafast ultrasound imaging is evaluated. The overall results from the simulations shows that the maximum effect of quantization errors on speckle noise is 0.18 dB, on the image contrast is 0.27 dB, on axial resolution is 2.38% and finally on lateral resolution is 1.44%. On the other hand, plane wave imaging (PWI) employing temporal averaging technique which is not bound with quantization errors relatively produces high contrast to noise ratio (CNR) and speckle signal to noise ratio (SSNR) at 40 MHz for both centre frequency compared to CPWI

Generalizations of the Hermite-Hadamard type inequalities for functions whose derivatives are s-convex

Some new results related to the right-hand side of the Hermite- Hadamard type inequality for the class of functions whose derivatives at certain powers are s-convex functions in the second sense are obtained

Enhancement of contrast and resolution of B-mode plane wave imaging (PWI) with non-linear filtered delay multiply and sum (FDMAS) beamforming

FDMAS has been successfully used in microwave imaging for breast cancer detection. FDMAS gained its popularity due to its capability to produce results faster than any other adaptive beamforming technique such as minimum variance (MV) which requires higher computational complexity. The average computational time for single point spread function (PSF) at 40 mm depth for FDMAS is 87 times faster than MV. The new beamforming technique has been tested on PSF and cyst phantoms experimentally with the ultrasound array research platform version 2 (UARP II) using a 3-8 MHz 128 element clinical transducer. FDMAS is able to improve both imaging contrast and spatial resolution as compared to DAS. The wire phantom main lobes lateral resolution improved in FDMAS by 40.4% with square pulse excitation signal when compared to DAS. Meanwhile the contrast ratio (CR) obtained for an anechoic cyst located at 15 mm depth for PWI with DAS and FDMAS are -6.2 dB and -14.9 dB respectively. The ability to reduce noise from off axis with auto-correlation operation in FDMAS pave the way to display the B-mode image with high dynamic range. However, the contrast to noise ratio (CNR) measured at same cyst location for FDMAS give less reading compared to DAS. Nevertheless, this drawback can be compensated by applying compound plane wave imaging (CPWI) technique on FDMAS. In overall the new FDMAS beamforming technique outperforms DAS in laboratory experiments by narrowing its main lobes and increases the image contrast without sacrificing its frame rates

Improved shear wave-front reconstruction method by aligning imaging beam angles with shear-wave polarization: Applied for shear compounding application

In shear compounding, shear waves are generated at various angles and individual elasticity maps are averaged to reduce noise and improve accuracy. The steered shear waves tilt the tissue motion direction therefore conventional plane wave tracking is not capable of capturing true shear wave amplitude and direction. The proposed method aligns the tracking beams with the shear wave angles, enables beam-axis in the direction of tissue motion to estimate true shear wave motion vector. In this experimental work, shear waves are produced at five different angles and motion is captured using proposed and conventional method. All the experiments are conducted using inclusion-based elasticity phantom. In the results, the displacement maps show that proposed method accurately captured the steered push-beam wave-fronts while conventional method produced push-beam direction artefacts. In the final compounded elasticity maps, the proposed method slightly improved background-to-inclusion elasticity ratio, CNR by 2 dB, and produced inclusion boundary shape sharper than the conventional tracking