Personal style and epistemic stance in classroom discussion

This article reports on an analysis of stance-taking in the university classroom, examining how students position themselves in relation to academic knowledge through the epistemic phrases I don’t know and I think. Analysis of specific interactional moments reveals that the meaning of discourse forms is largely indeterminate without an understanding of (1) the immediate discourse context; (2) the place of linguistic forms in an individual’s stylistic repertoire; and (3) the ideologies and social categories that frame that stylistic repertoire. Differential knowledge distribution amongst the students places constraints on what certain individuals can do with particular linguistic forms and this analysis reveals how they utilize the same linguistic resources in different ways in order to do different identity work. Through detailed interactional analysis, I demonstrate that our ability to evaluate classroom discussion as a social practice relies upon our ability to situate that practice within an understanding of individual speakers’ personal styles and the social ideologies that frame them

Magnetic and electric field meters developed for the US Department of Energy

This report describes work done at the Jet Propulsion Laboratory for the Office of Energy Storage and Distribution of DOE on the measurement of power line fields. A magnetic field meter is discussed that uses fiber optics to couple a small measuring probe to a remote readout device. The use of fiber optics minimizes electric field perturbation due to the presence of the probe and provides electric isolation for the probe, so that it could be used in a high field or high voltage environment. Power to operate the sensor electronics is transferred via an optical fiber, and converted to electrical form by a small photodiode array. The fundamental, the second and third harmonics of the field are filtered and separately measured, as well as the broadband rms level of the field. The design of the meter is described in detail and data from laboratory tests are presented. The report also describes work done to improve the performance of a DC bushing in a Swedish factory, using the improved meter. The DC electric fields are measured with synchronous detection to provide field magnitude data in two component directions

Intrinsic origin of electron scattering at 4H-SiC(0001)/SiO2_2

We introduce a first-principles study to clarify the carrier-scattering property at the SiC/SiO$_2$. Interestingly, the electron transport at the conduction-band edge is significantly affected by the introduction of oxygen, even though there are no electrically active defects. The origin of the large scattering is explained by the behavior of the internal-space states (ISSs). Moreover, the effect of the ISSs is larger than that of the electrically active carbon-related defects. This result indicates that an additional scattering not considered in a conventional Si/SiO$_2$ occurs at the SiC/SiO$_2$.Comment: 17 pages, 5 figure

Distribution automation applications of fiber optics

Motivations for interest and research in distribution automation are discussed. The communication requirements of distribution automation are examined and shown to exceed the capabilities of power line carrier, radio, and telephone systems. A fiber optic based communication system is described that is co-located with the distribution system and that could satisfy the data rate and reliability requirements. A cost comparison shows that it could be constructed at a cost that is similar to that of a power line carrier system. The requirements for fiber optic sensors for distribution automation are discussed. The design of a data link suitable for optically-powered electronic sensing is presented. Empirical results are given. A modeling technique that was used to understand the reflections of guided light from a variety of surfaces is described. An optical position-indicator design is discussed. Systems aspects of distribution automation are discussed, in particular, the lack of interface, communications, and data standards. The economics of distribution automation are examined

Clinical and radiological recurrence after childhood arterial ischemic stroke

Background: Data on rates and risk factors for clinical and radiological recurrence of childhood arterial ischemic stroke (AIS) might inform secondary prevention strategies. Methods and Results: Consecutive Great Ormond Street Hospital patients with first AIS were identified retrospectively (1978–1990) and prospectively (1990–2000). Patients underwent repeat neuroimaging at the time of clinical recurrence or, if asymptomatic, at least 1 year after AIS. Cox and logistic regression analyses were used to explore the relationships between risk factors and clinical and radiological recurrence, respectively. A total of 212 patients were identified, of whom 97 had another prior diagnosis. Seventy-nine children had a clinical recurrence (29 strokes, 46 transient ischemic attacks [TIAs], 4 deaths with reinfarction 1 day to 11.5 years (median 267 days) later); after 5 years, 59% (95% confidence interval, 51% to 67%) were recurrence free. Moyamoya on angiography and low birth weight were independently associated with clinical recurrence in the whole group. Genetic thrombophilia was associated with clinical recurrence in previously healthy patients, independent of the presence of moyamoya. Sixty of 179 patients who had repeat neuroimaging had radiological reinfarction, which was clinically silent in 20. Previous TIA, bilateral infarction, prior diagnosis (specifically immunodeficiency), and leukocytosis were independently associated with reinfarction. Previous TIA and leukocytosis were also independently associated with clinically silent reinfarction. Conclusions: Clinical and radiological recurrence are common after childhood AIS. The risk of clinical recurrence is increased in children with moyamoya and, in previously healthy patients, in those with genetic thrombophilia. Preexisting pathology, including immunodeficiency, and persistent leukocytosis are risk factors for radiological recurrence, which suggests a potential role for chronic infection

Automatic Fiscal Stabilisers: Implications for New Zealand

Automatic fiscal stabilisers, or the cyclical components of the budget balance, are larger in New Zealand than in the average OECD country, reflecting both higher sensitivity to the conomic cycle, and a more volatile cycle. Fiscal vigilance is especially important in New Zealand. Large projected operating surpluses could easily disappear if lower economic outcomes are mistakenly assumed to be cyclical. But, automatic stabilisers are difficult to use in a policy framework as empirical estimates of the cyclical budget balance vary significantly. While the estimated trend in automatic stabilisers is broadly similar, the level varies significantly, such that at any point in time a 'structural surplus' may be dependant on the estimation method.automatic fiscal stabilisers; economic cycle; cyclical budget balance; expenditure and tax elasticities