2,104 research outputs found

    Cities as emergent models: the morphological logic of Manhattan and Barcelona

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    This paper is set to unveil several particulars about the logic embedded in the diachronic model of city growth and the rules which govern the emergence of urban spaces. The paper outlines an attempt to detect and define the generative rules of a growing urban structure by means of evaluation techniques. The initial approach in this regards will be to study the evolution of existing urban regions or cities which in our case are Manhattan and Barcelona and investigate the rules and causes of their emergence and growth. The paper will concentrate on the spatial aspect of the generative rules and investigate their behaviour and dimensionality. Several Space Syntax evaluation methods will be implemented to capture the change of spatial configurations within the growing urban structures. In addition, certain spatial elements will be isolated and tested aiming to illustrate their influence on the main spatial structures. Both urban regions were found to be emergent products of a bottom up organic growth mostly distinguished in the vicinities of the first settlements. Despite the imposition of a uniform grid on both cities in later stages of their development these cities managed to deform the regularity in the preplanned grid in an emergent manner to end up with an efficient model embodied in their current spatial arrangement. The paper reveals several consistencies in the spatial morphology of both urban regions and provides explanation of these regularities in an approach to extract the underlying rules which contributed to the growth optimization process

    Thermal Reshaping of Gold Nanorods in Micellar Solution of Water/Glycerol Mixtures

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    Gold nanorods (Nds) with aspect ratios of 4, 3.5, and 2.8 were prepared by the electrochemical method. The nanorods were thermally studied in binary solvents of aqueous glycerol at different ratios (25%–75%). The results illustrated that the longitudinal surface plasmon resonance (SPL) is strongly dependent on the dielectric constant. The maximum absorption is red shifted with increasing the glycerol/water ratio. This was attributed to the decreasing value of the dielectric constant of the binary solvents. Moreover, by increasing the temperatures, the results showed relative instability of the gold nanorods. This attributed to the relative instability of the micelle capping the nanorods

    The Effectiveness of a Proposed Enrichment Program Based on Problem-Solving and Problem Posing in Developing the Ability of Mathematical Reasoning and Sense-Making among Grade Ten High Achievers

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    This study aimed to reveal the effectiveness of a proposed enrichment program based on problem-solving and problem posing in developing the ability of the mathematical reasoning and sense making among students of high achievement. To achieve this goal, an enrichment training program was designed to focus on a set of mathematical ideas and skills in mathematics using problem-solving and problem- posing strategies to solve and pose non-routine mathematical problems for students of high achievement to develop their mathematical reasoning and sense making ability. The researcher designed a test to measure the mathematical reasoning and sense making. In addition, the Test of Mathematical Abilities (TOMA-3) was used to measure the students' mathematical abilities before the experiment. The sample of the study consisted of 63 grade ten high achievers randomly selected from South Batinah governorate, which was divided into control and experimental groups. For testing the study hypothesis, data was analyzed by analysis of covariance (ANCOVA) in which eta squared was obtained. The results showed that the proposed program was effective and the mathematical reasoning and sense making skills were highly achieved

    An investigation into the cognitive, metacognitive, and spatial markers of creativity and efficiency in architectural design

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    This paper presents a preliminary study into the spatial features that can be used to distinguish creativity andefficiency in design layouts, and the distinct pattern of cognitive and metacognitive activity that is associated with creative design. In a design experiment, a group of 12 architects were handed a design brief. Their drawing activity was recorded and they were required to externalize their thoughts during the design process. Both design solutions and verbal comments were analysed and modelled. A separate group of experienced architects used their expert knowledge to assign creativity and efficiency scores to the 12 design solutions. The design solutions were evaluated spatially. Protocol analysis studies including linkography and macroscopic analysis were used to discern distinctive patterns in the cognitive and metacognition activity of designs marked with the highest and least creativity scores. Entropy models of the linkographs and knowledge graphs were further introduced Finally, we assessed how creativity and efficiency correlates to experiment variables, cognitive activity, metacognitive activity, spatial and functional distribution of spaces in the design solutions, and the number and type of design constraints applied through the course of design. Through this investigation, we suggest that expert knowledge can be used to assess creativity and efficiency in designs. Our findings indicate that efficient layouts have distinct spatial features, and that cognitive and metacognitive activity in design that yields a highly creative outcome corresponds to higher frequencies of design moves and higher linkages between design moves

    Optical signatures of intrinsic electron localization in amorphous SiO2

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    We measure and analyse the optical absorption spectra of three silica glass samples irradiated with 1 MeV electrons at 80 K, where self-trapped holes are stable, and use ab initio calculations to demonstrate that these spectra contain a signature of intrinsic electron traps created as counterparts to the holes. In particular, we argue that optical absorption bands peaking at 3.7, 4.7, and 6.4 eV belong to strongly localised electrons trapped at precursor sites in amorphous structure characterized by strained Si–O bonds and O–Si–O angles greater than 132°. These results are important for our understanding of the properties of silica glass and other silicates as well as the reliability of electronic and optical devices and for luminescence dating

    Multiple Venous Malformations as a Cause of Pulsatile Tinnitus.

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    INTRODUCTION: Pulsatile tinnitus is a relatively common presentation in otolaryngology clinics, most cases of which have a treatable cause. This presentation warrants a thorough workup to identify treatable, and rule out life-threatening, etiologies. We present a case of a patient with pulsatile tinnitus arising from multiple dilated venous channels in the head and neck. Case Presentation. We present the case of a 65-year-old Caucasian female with a two-year history of progressive, bilateral pulsatile tinnitus, which had become debilitating. Computed-tomographic angiography (CTA) studies ruled out an intracranial vascular cause for her symptoms. However, computed tomography (CT) scanning and magnetic resonance imaging (MRI) revealed multiple dilated bilateral, low-flow, venous channels throughout the head and neck. The proximity of such dilated venous channels to the temporal bone provides a route for sound to be transmitted to the inner ear. CONCLUSION: Arterial, venous, and systemic etiologies can cause pulsatile tinnitus. Arteriovenous malformations (AVMs) of the head and neck represent less than 1% of cases. In our patient, dilated low-flow venous malformations are the likely source of her symptoms, which is the first reported case in the literature.Peer Reviewe

    Being a mobile international postgraduate research student with family in the United Kingdom: conflict, contestation, and contradictions

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    The internationalisation of higher education has influenced the dramatic rise in the mobility of students, academics and knowledge across borders. There has been growing research interest focusing on international students studying abroad. While the student experience is an area of education that is often researched, most research focuses on experiences of undergraduate students. Also in the context of international students, greater research emphasis has been placed on the academic experiences and support available for undergraduates. While such research is important, less attention has been paid to the non-academic experiences of International Post-Graduate Research Students with Families (IPGRSF). This article seeks to fill this gap by focusing on the social worlds of IPGRSF in the UK, examining students’ nuclear family contexts that are often marginalised in discourse. The article legitimises the IPGRSF subaltern world by focusing on how students negotiate its demands; how they negotiate their roles as research students with their other roles as spouses and parents, and the interrelationships among these roles; and how the university as an institution interacts with the students’ subaltern world. The findings show that language plays a significant role in shaping the process of mobility as well as influencing the students’ and their families’ integration and networking in the host country. Also, the findings suggest that students often had positive experiences at departmental level, but felt let down by the wider university support
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