The Effectiveness of Blended Learning by Using "Google Classroom" on the Achievement and Attitudes toward Mathematics of the Fourth-Grade Students

هدفت الدراسة الحالية، إلى الكشف عن أثر التعلم المدمج في التحصيل الدراسي في الرياضيات لدى تلاميذ الصف الرابع واتجاهاتهم نحوها باستخدام أحد التطبيقات المستندة إلى الحوسبة السحابية (فصول جوجل Google Classroom). وطبقت الدراسة على عينة من تلاميذ مدرسة المنهل الدولية، للعام الدراسي 2018\2019، المكونة من شعبتين من الصف الرابع وعددهم 61 تلميذاً، وتكونت المجموعة التي خضعت للتعلم المدمج من 31  تلميذاً، بينما تكونت مجموعة التعليم الاعتيادي من 30 تلميذاً. ولتحقيق أهداف الدراسة استُخدم المنهج شبه التجريبي. واستُخدمت في الدراسة أداتان: اختبار التحصيل الدراسي في الرياضيات، ومقياس الاتجاهات نحو الرياضيات. وأظهرت نتائج الدراسة أن هناك فروقاً دالة إحصائيا في مستوى التحصيل الدراسي، والاتجاهات نحو الرياضيات، لصالح مجموعة التعلم المدمج. وأن هنالك علاقة ارتباط إيجابية دالة إحصائيا بين التحصيل الدراسي، والاتجاهات نحو الرياضيات.This study aimed to investigate the effectiveness of blended learning using Google classroom application on grade fours student’s achievement in mathematics and their attitudes toward it. The study sample consisted of 61 students of the fourth-grade students at Manhal International School in 2018\2019 academic year. The sample was divided into two study groups, a group of blended learning consisting of 31 students and a conventional group consisting of 30 students. The quasi-experimental analysis method was used to achieve the objectives of the study. Two tools were used in the study: Academic achievement test in probability and statistics, and questionnaire of attitudes towards mathematics. The study results showed that there were statistically significant differences in academic achievement and attitudes toward mathematics in favour of blended learning group, and there was a significant positive correlation between academic achievement and attitudes towards mathematic

A clumpy and anisotropic galaxy halo at z=1 from gravitational-arc tomography

Every star-forming galaxy has a halo of metal-enriched gas extending out to at least 100 kpc, as revealed by the absorption lines this gas imprints on the spectra of background quasars. However, quasars are sparse and typically probe only one narrow pencil beam through the intervening galaxy. Close quasar pairs and gravitationally lensed quasars have been used to circumvent this inherently one-dimensional technique, but these objects are rare and the structure of the circum-galactic medium remains poorly constrained. As a result, our understanding of the physical processes that drive the re-cycling of baryons across the lifetime of a galaxy is limited. Here we report integral-field (tomographic) spectroscopy of an extended background source -a bright giant gravitational arc. We can thus coherently map the spatial and kinematic distribution of Mg II absorption -a standard tracer of enriched gas- in an intervening galaxy system at redshift 0.98 (i.e., ~8 Gyr ago). Our gravitational-arc tomography unveils a clumpy medium in which the absorption-strength decreases with increasing impact parameter, in good agreement with the statistics towards quasars; furthermore, we find strong evidence that the gas is not distributed isotropically. Interestingly, we detect little kinematic variation over a projected area of ~600 kpc squared, with all line-of-sight velocities confined to within a few tens of km/s of each other. These results suggest that the detected absorption originates from entrained recycled material, rather than in a galactic outflow.Comment: Published online in Nature on 31 January 201

Fluid–structure interaction of free convection in a square cavity divided by a flexible membrane and subjected to sinusoidal temperature heating

Purpose: The purpose of the present paper is to model a cavity, which is equally divided vertically by a thin, flexible membrane. The membranes are inevitable components of many engineering devices such as distillation systems and fuel cells. In the present study, a cavity which is equally divided vertically by a thin, flexible membrane is model using the fluid–structure interaction (FSI) associated with a moving grid approach. Design/methodology/approach: The cavity is differentially heated by a sinusoidal time-varying temperature on the left vertical wall, while the right vertical wall is cooled isothermally. There is no thermal diffusion from the upper and lower boundaries. The finite-element Galerkin technique with the aid of an arbitrary Lagrangian–Eulerian procedure is followed in the numerical procedure. The governing equations are transformed into non-dimensional forms to generalize the solution. Findings: The effects of four pertinent parameters are investigated, i.e., Rayleigh number (104 = Ra = 107), elasticity modulus (5 × 1012 = ET = 1016), Prandtl number (0.7 = Pr = 200) and temperature oscillation frequency (2p = f = 240p). The outcomes show that the temperature frequency does not induce a notable effect on the mean values of the Nusselt number and the deformation of the flexible membrane. The convective heat transfer and the stretching of the thin, flexible membrane become higher with a fluid of a higher Prandtl number or with a partition of a lower elasticity modulus. Originality/value: The authors believe that the modeling of natural convection and heat transfer in a cavity with the deformable membrane and oscillating wall heating is a new subject and the results have not been published elsewhere

Synthesis and Characterization of some New 1,3,4-Oxadiazole derivatives based on 4-amino benzoic acid

Various of 2,5- disubstituted 1,3,4-oxadiazole (Schiff base, ?- lactam and azo) were synthesized from 2,5-di (4,4?-amino-1,3,4-oxadiazole which usequently synth-esized from mixture of 4- amino benzoic acid and hydrazine arch of polyphosphorus acid. The synthesized compounds were cherecterized by using some spectral data (UV, FT-IR , and 1H-NMR

Descripción de los corales rugosos y tabulados del Serpukhoviense de las formaciones Idmarrach y Tirhela (Adarouch, Marruecos)

Se describen los corales rugosos y tabulados de las formaciones Idmarrach y Tirhela, que se localizan en el área de Adarouch, en la Meseta central de Marruecos. Se han identificado 32 especies de corales rugosos pertenecientes a 19 géneros y una especie de coral tabulado. Las asociaciones de edad Serpukhoviense de las formaciones estudiadas están compuestas en su mayoría por especies que tienen su máximo desarrollo en el Viseense superior. Sin embargo, la mayoría de los taxones identificados en Adarouch han sido mencionados previamente en rocas del Serpukhoviense de otras regiones del Paleotethys occidental y las cuencas epicontinentales del norte de África. Las asociaciones de corales están dominadas por corales coloniales pertenecientes a la familia Lithostrotionidae y por corales solitarios pertenecientes a la familia Aulophyllidae. Son también frecuentes los representantes de las familias Axophyllidae, Cyathaxoniidae, Cyathopsidae, Palaeosmiliidae, Stereophrentidae y Zaphrentoididae. El medio de desarrollo de los corales estudiados fue una plataforma carbonatada interna a media con importantes aportes de terrígenos finos.The Serpukhovian coral assemblages from the Idmarrach and Tirhela formations in Central Morocco are described. 32 rugose species belonging to 19 genera and 1 tabulate species have been identified. The Serpukhovian assemblages are composed mostly of species that have their greater abundance in the upper Viséan. However, most recorded taxa in Adarouch have been already mentioned in Serpukhovian rocks from other regions in the Palaeotethys and in North African epicontinental basins. The coral assemblage is dominated by colonial corals belonging to the family Lithostrotionidae and solitary corals belonging to the family Aulophyllidae. In addition, representatives of the families Axophyllidae, Cyathaxoniidae, Cyathopsidae, Palaeosmiliidae, Stereophrentidae and Zaphrentoididae are also present in the assemblages. The environment where the corals lived was mostly an inner to middle carbonate platform with a minor but significant input of terrigenous sediments.Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEMinisterio de Ciencia e Innovación (MICINN)pu

The BOSS Emission-Line Lens Survey. III. : Strong Lensing of Lyα\alpha Emitters by Individual Galaxies

We introduce the Baryon Oscillation Spectroscopic Survey (BOSS) Emission-Line Lens Survey (BELLS) for GALaxy-Ly$\alpha$ EmitteR sYstems (BELLS GALLERY) Survey, which is a Hubble Space Telescope program to image a sample of galaxy-scale strong gravitational lens candidate systems with high-redshift Ly$\alpha$ emitters (LAEs) as the background sources. The goal of the BELLS GALLERY Survey is to illuminate dark substructures in galaxy-scale halos by exploiting the small-scale clumpiness of rest-frame far-UV emission in lensed LAEs, and to thereby constrain the slope and normalization of the substructure-mass function. In this paper, we describe in detail the spectroscopic strong-lens selection technique, which is based on methods adopted in the previous Sloan Lens ACS (SLACS) Survey, BELLS, and SLACS for the Masses Survey. We present the BELLS GALLERY sample of the 21 highest-quality galaxy--LAE candidates selected from $\approx 1.4 \times 10^6$ galaxy spectra in the BOSS of the Sloan Digital Sky Survey III. These systems consist of massive galaxies at redshifts of approximately 0.5 strongly lensing LAEs at redshifts from 2--3. The compact nature of LAEs makes them an ideal probe of dark substructures, with a substructure-mass sensitivity that is unprecedented in other optical strong-lens samples. The magnification effect from lensing will also reveal the structure of LAEs below 100 pc scales, providing a detailed look at the sites of the most concentrated unobscured star formation in the universe. The source code used for candidate selection is available for download as a part of this release.Comment: 14 pages, 5 figures, accepted for publication in the ApJ (ApJ, 824, 86). Minor edits to match the ApJ published versio

Introducing the Journal of Melittology: An outlet for disseminating bee research and raising melittological awareness

A new journal is introduced, the focus of which is to disseminate the results of research on wild and managed bees, to raise public awareness of bees, and to promote and facilitate international communication and collaboration

Growth laws and self-similar growth regimes of coarsening two-dimensional foams: Transition from dry to wet limits

We study the topology and geometry of two dimensional coarsening foams with arbitrary liquid fraction. To interpolate between the dry limit described by von Neumann's law, and the wet limit described by Marqusee equation, the relevant bubble characteristics are the Plateau border radius and a new variable, the effective number of sides. We propose an equation for the individual bubble growth rate as the weighted sum of the growth through bubble-bubble interfaces and through bubble-Plateau borders interfaces. The resulting prediction is successfully tested, without adjustable parameter, using extensive bidimensional Potts model simulations. Simulations also show that a selfsimilar growth regime is observed at any liquid fraction and determine how the average size growth exponent, side number distribution and relative size distribution interpolate between the extreme limits. Applications include concentrated emulsions, grains in polycrystals and other domains with coarsening driven by curvature