1,109 research outputs found

    Fractal dimension and size scaling of domains in thin films of multiferroic BiFeO3

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    We have analyzed the morphology of ferroelectric domains in very thin films of multiferroic BiFeO3. Unlike the more common stripe domains observed in thicker films BiFeO3 or in other ferroics, the domains tend not to be straight, but irregular in shape, with significant domain wall roughening leading to a fractal dimensionality. Also contrary to what is usually observed in other ferroics, the domain size appears not to scale as the square root of the film thickness. A model is proposed in which the observed domain size as a function of film thickness can be directly linked to the fractal dimension of the domains.Comment: 4 pages, 3 figure

    Effect of cloud transits in a stand-alone solar photovoltaic water pumping system

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    This paper discusses the effects of cloud transit on a stand-alone direct solar photovoltaic water pumping system for irrigation and farms. In this way, its impact is studied, applying a possible classification based on its incidence and effects on the system. For this, the information provided by the data loggers of different photovoltaic installations has been analyzed and in turn compared with the data obtained in the reference installation. In addition, the Matlab-Simulink simulation model used is described. Different simulations have been developed to verify the basic characteristics of the proposed system. In this way, it is possible to check the advantages and drawbacks of the direct water pumping in irrigation applications. At the same time, the system parameters can be easily modified to meet the requirements of different water flow capacities. Also, the water hammer effect and the cavitation phenomenon in the water pump are described. Finally, the simulation results obtained as well as their conclusions are presented

    Comparison of Electronic Physician Prompts versus Waitroom Case-Finding on Clinical Trial Enrollment

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    BACKGROUND: Recruiting patients into clinical research protocols is challenging. Electronic medical record (EMR) systems capable of prompting clinicians may facilitate enrollment. OBJECTIVE: To compare an EMR-based clinician prompt versus a wait-room-based case-finding strategy at enrolling patients into a clinical trial. DESIGN: Cross-sectional comparison of recruitment data from two trials to treat anxiety disorders in primary care. Both studies utilized similar enrollment criteria, intervention strategies, and the same four practice sites and EMR system. PARTICIPANTS: Patients referred by their (primary care physicians) PCPs in response to an EMR prompt (recruited 1/2005–10/2006), and patients enrolled by research assistants stationed in practice waiting rooms (7/2000–4/2002). MEASUREMENTS: Referral counts, patients’ baseline sociodemographic and clinical characteristics. RESULTS: Over a 22-month period, EMR-prompted PCPs referred 794 patients and 176 (22%) met study inclusion criteria and enrolled, compared to 8,095 patients approached by wait room-based recruiters of whom 193 (2.4%) enrolled. Subjects enrolled by EMR-prompted PCPs were more likely to be non-white (23% vs 5%; P < 0.001), male (28% vs 18%; P = 0.03), and have higher anxiety levels than those recruited by wait-room recruiters (P < 0.0001). CONCLUSIONS: EMR systems prompting clinicians to refer patients with specific characteristics are an efficient recruitment tool with critical implications for increasing minority participation in clinical research

    The spatial and compositional evolution of the Jurassic Ghorveh-Dehgolan plutons of the Zagros Orogen, Iran: SHRIMP zircon U-Pb and Sr and Nd isotope evidence

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    The Ghorveh-Dehgolan plutons of the northern Sanandaj-Sirjan Zone, Zagros Orogen, comprise seven composite intrusive bodies that were generated during northeastward subduction of Neotethys beneath the Iranian sector of the Eurasian plate. Zircon U-Pb SHRIMP dating reveals that the magmatic activity spanned from ~160 to ~140Ma. It started with intrusion of arc-related calc-alkaline mafic to intermediate rocks closely followed by felsic I-type granitoids. This magmatism was post-dated by felsic alkaline A-type granites. In addition to compositional changes over time, the plutons forming the arc young towards the southwest: the north Ghorveh batholith (161±4Ma) and Shanevareh (160±2Ma); Qalaylan (159±3Ma); then central Ghorveh, Galali and Saranjianeh (151±0.2Ma to 148±1Ma); and, lastly, the south Ghorveh batholith (147±3Ma) and Bolbanabad-Havarpan (144±1Ma). Whatever the process driving the changes, be it arc- or ridge-collision with the subducting system, slab roll-back, slab breakoff, subduction initiation transference, etc., the progression from I-type to A-type magmatism appears to mark a significant change from a collisional to an extensional setting in the region in the Late Jurassic. Geochemical and isotopic characteristics of the Ghorveh-Dehgolan plutons indicate that Arabian-Nubian-like crust was an important component of the magmatic sources

    Teaching Strategies for Diverse Classrooms: Including the Non-traditional Student

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    Adult enrollment in higher education increased by 50 percent between 1991 and 2011, and continues to increase while traditional enrollments decline across America. How to meet the diverse needs of adults continuing their education part-time while juggling work, family and community commitments is a challenge. Attend this workshop to increase your understanding of teaching strategies that make online and face-to-face learning activities more applicable for non-traditional learners

    In search of a novel way to analyze early communicative behavior

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    The aim of this study was to develop a coding scheme that enables researchers and practitioners to conduct a detailed analysis of the communicative behavior of young children with significant cognitive and motor developmental delays. Currently, there is a paucity of methods to do conduct such an analysis. For the study, video observations of three different scenarios from 38 children with significant cognitive and motor developmental delays aged between 12 and 54 months, were used. Findings from the video observations served as the primary means for development of the coding scheme, which comprises three main categories – context, partner behavior, and individual behavior – and several subcategories. The coding scheme was used to document the early expressive communicative behavior of persons with significant cognitive and motor developmental delays in a detailed manner. This fine-grained information is necessary to differentiate children based on their communicative abilities, to monitor their communicative development longitudinally, and to inform person-centered communicative interventions

    Failure to Detect Critical Auditory Alerts in the Cockpit: Evidence for Inattentional Deafness

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    Objective: The aim of this study was to test whether inattentional deafness to critical alarms would be observed in a simulated cockpit. Background: The inability of pilots to detect unexpected changes in their auditory environment (e.g., alarms) is a major safety problem in aeronautics. In aviation, the lack of response to alarms is usually not attributed to attentional limitations, but rather to pilots choosing to ignore such warnings due to decision biases, hearing issues, or conscious risk taking. Method: Twenty-eight general aviation pilots performed two landings in a flight simulator. In one scenario an auditory alert was triggered alone, whereas in the other the auditory alert occurred while the pilots dealt with a critical windshear. Results: In the windshear scenario, 11 pilots (39.3%) did not report nor react appropriately to the alarm whereas all the pilots perceived the auditory warning in the no-windshear scenario. Also, of those pilots who were first exposed to the no-windshear scenario and detected the alarm, only three suffered from inattentional deafness in the subsequent windshear scenario. Conclusion: These findings establish inattentional deafness as a cognitive phenomenon that is critical for air safety. Pre-exposure to a critical event triggering an auditory alarm can enhance alarm detection when a similar event is encountered subsequently. Application: Case-based learning is a solution to mitigate auditory alarm misperception
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