3,858 research outputs found
Spin transport in proximity induced ferromagnetic graphene
Magnetic gates in close proximity to graphene can induce ferromagnetic
correlations. We study the effect of such induced magnetization dependent
Zeeman splittings on the graphene transport properties. We estimate that
induced spin splittings of the order of \Delta ~ 5 meV could be achieved with
the use of magnetic insulator gates, e.g. EuO-gates, deposited on top of
graphene. We demonstrate that such splittings in proximity induced
ferromagnetic graphene could be determined directly from the tunneling
resonances in the linear response conductance, as the top gate creates also a
tunable barrier in the graphene layer. We show how such splittings could also
be determined independently by magnetoresistance measurements in a spin-valve
geometry. Because the spin polarization of the current near the Dirac point
increases with the length of the barrier, long magnetic gates are desirable for
determining \Delta experimentally.Comment: 9 pages, 11 figure
Interviewing suspects: examining the association between skills, questioning, evidence disclosure, and interview outcomes
The interviewing of suspects is an important element in the investigation of crime. However, studies concerning actual performance of investigators when undertaking such interviews remain sparse. Nevertheless, in England and Wales, since the introduction of a prescribed framework over 20 years ago, field studies have generally shown an improvement in interviewing performance, notwithstanding ongoing concerns largely relating to the more demanding aspects (such as building/maintaining rapport, intermittent summarising and the logical development of topics). Using a sample of 70 real-life interviews, the present study examined questioning and various evidence disclosure strategies (which have also been found demanding), examining their relationships between interview skills and interview outcomes. It was found that when evidence was disclosed gradually (but revealed later), interviews were generally both more skilled and involved the gaining of comprehensive accounts, whereas when evidence was disclosed either early or very late, interviews were found to be both less skilled and less likely to involve this outcome. These findings contribute towards an increased research base for the prescribed framework
Dissociation of writing processes: A functional magnetic resonance imaging study on the neural substrates for the handwritten production of Chinese characters
Writing is an important way to communicate in everyday life because it can convey information over time and space, but its neural substrates remain poorly known. Although the neural basis of written language production has been investigated in alphabetic scripts, it has rarely been examined in nonalphabetic languages such as Chinese. The present functional magnetic resonance imaging study explored the neural substrates of handwritten word production in Chinese and identified the brain regions sensitive to the psycholinguistic factors of word frequency and syllable frequency. To capture this, we contrasted neural activation in “writing” with “speaking plus drawing” and “watching plus drawing.” Word frequency (high, low) and syllable frequency (high, low) of the picture names were manipulated. Contrasts between the tasks showed that writing Chinese characters was mainly associated with brain activation in the left frontal and parietal cortex, whereas orthographic processing and the motor procedures necessary for handwritten production were also related to activation in the right frontal and parietal cortex as well as right putamen/thalamus. These results demonstrate that writing Chinese characters requires activation in bilateral cortical regions and the right putamen/thalamus. Our results also revealed no brain activation associated with the main effects of word frequency and syllable frequency as well as their interaction, which implies that word frequency and syllable frequency may not affect the writing of Chinese characters on a neural level
Conducting language production research online: A web-based study of semantic context and name agreement effects in multi-word production
Few web-based experiments have explored spoken language production, perhaps due to concerns of data quality, especially for measuring onset latencies. The present study highlights how speech production research can be done outside of the laboratory by measuring utterance durations and speech fluency in a multiple-object naming task when examining two effects related to lexical selection: semantic context and name agreement. A web-based modified blocked-cyclic naming paradigm was created, in which participants named a total of sixteen simultaneously presented pictures on each trial. The pictures were either four tokens from the same semantic category (homogeneous context), or four tokens from different semantic categories (heterogeneous context). Name agreement of the pictures was varied orthogonally (high, low). In addition to onset latency, five dependent variables were measured to index naming performance: accuracy, utterance duration, total pause time, the number of chunks (word groups pronounced without intervening pauses), and first chunk length. Bayesian analyses showed effects of semantic context and name agreement for some of the dependent measures, but no interaction. We discuss the methodological implications of the current study and make best practice recommendations for spoken language production research in an online environment
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Model of Woven Electrode Designed for Long-Term Capture of Electrocardiograph
There is a growing demand to continuously monitor the ECG over longer periods of time. This demand comes from all areas of life; from tracking sickness for improved treatment and prevention to optimizing performance for athletes and workers in dangerous environments. To meet this demand, wearable devices are designed to monitor health status continuously and autonomously. This is called wellness monitoring, and it has been shown to improve quality of life by reducing reliance on reactive treatments. When wellness monitoring is applied to ECG systems, the existing solutions have a variety of limitations oriented around the limits of traditional electrodes. Conductive textile electrodes offer an alternative to traditional electrodes but they come with their own challenges. One of the key challenges with textile electrodes is that it is not well understood how a given set of manufacturing parameters influence the ECG measurement. The current ways of relating manufacturing parameters to ECG measurements rely on physical trial-and-error methodologies which inhibit design cycle iterations. This research presents a novel model of the ECG system, which ties the electrical behavior of woven textile electrodes to their manufacturing parameters. Specifically, this research investigates how the yarn type, weave pattern, and patch area of a woven electrode are related to the circuit parameters in the skin-electrode interface model. A parameterized model of the ECG system was constructed which depends on the circuit parameter of the skin-electrode interface as well as the circuit parameters of the associated circuitry. Through this relationship, the circuit parameters corresponding to woven electrodes were fit using an optimizer that minimizes the differences between a simulated and measured waveform. This equivalent model demonstrated for the first time the relationship between woven electrode manufacturing parameters and their electrical circuit parameters. By using this model, woven electrodes can be better designed for optimal ECG capture capability. Furthermore, ECG circuitry can be customized to accommodate the variation between different types of electrodes. This work builds from previous work on textile sensor development and enables future work to target even better textile sensor design.</p
Mitochondrial portrait of the Cabo Verde archipelago: the Senegambian outpost of Atlantic slave trade
In order to study the matrilineal genetic composition in Cabo Verde (Republic of Cape Verde), an archipelago that used to serve as a Portuguese entrepĂ´t of the Atlantic slave trade, we have analysed a total of 292 mtDNAs sampled from the seven inhabited islands for the hypervariable segment I (HVS-I) and some characteristic RFLPs of the coding regions. The different settlement history of the northwestern group of the islands is well reflected in the mtDNA pool. The total Cabo Verde sample clearly displays the characteristic mitochondrial features of the Atlantic fringe of western Africa and testifies to almost no mitochondrial input from the Portuguese colonizers.info:eu-repo/semantics/publishedVersio
Noise Characteristics of a Four-Jet Impingement Device Inside a Broadband Engine Noise Simulator
The noise generation mechanisms for four directly impinging supersonic jets are investigated employing implicit large eddy simulations with a higher-order accurate weighted essentially non-oscillatory shock-capturing scheme. Impinging jet devices are often used as an experimental apparatus to emulate a broadband noise source. Although such devices have been used in many experiments, a detailed investigation of the noise generation mechanisms has not been conducted before. Thus, the underlying physical mechanisms that are responsible for the generation of sound waves are not well understood. The flow field is highly complex and contains a wide range of temporal and spatial scales relevant for noise generation. Proper orthogonal decomposition of the flow field is utilized to characterize the unsteady nature of the flow field involving unsteady shock oscillations, large coherent turbulent flow structures, and the sporadic appearance of vortex tubes in the center of the impingement region. The causality method based on Lighthill's acoustic analogy is applied to link fluctuations of flow quantities inside the source region to the acoustic pressure in the far field. It will be demonstrated that the entropy fluctuation term in the Lighthill's stress tensor plays a vital role in the noise generation process. Consequently, the understanding of the noise generation mechanisms is employed to develop a reduced-order linear acoustic model of the four-jet impingement device. Finally, three linear acoustic FJID models are used as broadband noise sources inside an engine nacelle and the acoustic scattering results are validated against far-field acoustic experimental data
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