General Electric (Canada)

Rationale: Altered cardiac energetics is known to play an important role in the progression toward heart failure. A noninvasive method for imaging metabolic markers that could be used in longitudinal studies would be useful for understanding therapeutic approaches that target metabolism. Objective: To demonstrate the first hyperpolarized 13 C metabolic magnetic resonance imaging of the human heart. Methods and Results: Four healthy subjects underwent conventional proton cardiac magnetic resonance imaging followed by 13 C imaging and spectroscopic acquisition immediately after intravenous administration of a 0.1 mmol/kg dose of hyperpolarized [1- 13 C]pyruvate. All subjects tolerated the procedure well with no adverse effects reported ≤1 month post procedure. The [1- 13 C]pyruvate signal appeared within the chambers but not within the muscle. Imaging of the downstream metabolites showed 13 C-bicarbonate signal mainly confined to the left ventricular myocardium, whereas the [1- 13 C]lactate signal appeared both within the chambers and in the myocardium. The mean 13 C image signal:noise ratio was 115 for [1- 13 C]pyruvate, 56 for 13 C-bicarbonate, and 53 for [1- 13 C]lactate. Conclusions: These results represent the first 13 C images of the human heart. The appearance of 13 C-bicarbonate signal after administration of hyperpolarized [1- 13 C]pyruvate was readily detected in this healthy cohort (n=4). This shows that assessment of pyruvate metabolism in vivo in humans is feasible using current technology. Clinical Trial Registration: URL: https://www.clinicaltrials.gov . Unique identifier: NCT02648009.

Synchronized phasor measurements are becoming an important element of wide area measurement systems used in advanced power system monitoring, protection, and control applications. The recently issued revised standard C37.118 for synchrophasors has facilitated interoperability of phasor measurement units (PMUs) from different manufacturers. This standard defines performance for compliance when the input signals are in steady state. The performance of PMUs under transient conditions is not considered by the standard at this time, although clearly PMUs will be subjected to inputs under transient conditions. This paper is an attempt to provide the authors' views on how one may approach the question of standardizing PMU response under transient conditions.

The problem of designing realistic multivariable controllers to solve the servomechanism problem is considered in this paper. Specifically, it is desired to find a controller for a plant to solve the robust servomechanism problem, so that closed-loop stability and asymptotic regulation occur, and also so that other desirable properties of the controlled system, such as fast response, low-interaction, integrity, tolerance to plant variations, etc., occur. The method of design is based on using state space methods via a two-stage process: 1) using theory, determine the existence of a solution and control structure required to solve the problem, and 2) using nonlinear programming methods, determine the unknown controller parameters so as to minimize a performance index for the system subject to certain constraint requirements. Numerous examples, varying from a single-input/single-output to a four-input/four-output system, are given to illustrate the design method, and the results obtained are compared with the results obtained by using other alternate design methods. In all cases, the controllers obtained have been highly competitive with controllers obtained by alternate design methods.

A coherent binary FSK modulation system is discussed, that has the following properties: 1) it is phase coherent; 2) it has a low deviation ratio, <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">h = \frac{1}{2}; 3</tex> ) it occupies a small RF bandwidth, typically only 0.75 times the bit rate, without need for intersymbol interference correction; 4) it uses as receiver a self-synchronizing circuit and a phase detector, which together achieve optimal decisions; and 5) its error performance is about S dB better than that of conventional FSK.

The purpose of this study is to investigate multiregion graph cut image partitioning via kernel mapping of the image data. The image data is transformed implicitly by a kernel function so that the piecewise constant model of the graph cut formulation becomes applicable. The objective function contains an original data term to evaluate the deviation of the transformed data, within each segmentation region, from the piecewise constant model, and a smoothness, boundary preserving regularization term. The method affords an effective alternative to complex modeling of the original image data while taking advantage of the computational benefits of graph cuts. Using a common kernel function, energy minimization typically consists of iterating image partitioning by graph cut iterations and evaluations of region parameters via fixed point computation. A quantitative and comparative performance assessment is carried out over a large number of experiments using synthetic grey level data as well as natural images from the Berkeley database. The effectiveness of the method is also demonstrated through a set of experiments with real images of a variety of types such as medical, synthetic aperture radar, and motion maps.

Small-animal imaging has become increasingly more important as transgenic and knockout mice are produced to model human diseases. One imaging technique that has emerged is microcomputed tomography (micro-CT). For live-animal imaging, the precision in the images will be determined by the x-ray dose given to the animal. As a result, we propose a simple method to predict the noise performance of an x-ray micro-CT system as a function of dose and image resolution. An ideal, quantum-noise limited micro-CT scanner, assumed to have perfect resolution and ideal efficiency, was modeled. Using a simplified model, the coefficient of variation (COV) of the linear attenuation coefficient was calculated for a range of entrance doses and isotropic voxel sizes. COV calculations were performed for the ideal case and with simulated imperfections in efficiency and resolution. Our model was validated in phantom studies and mouse images were acquired with a specimen scanner to illustrate the results. A simplified model of noise propagation in the case of isotropic resolution indicates that the COV in the linear attenuation coefficient is proportional to (dose)(-1/2) and to the (isotropic voxel size)(-2) in the reconstructed volume. Therefore an improvement in the precision can be achieved only by increasing the isotropic voxel size (thereby decreasing the resolution of the image) or by increasing the x-ray dose. For the ideal scanner, a COV of 1% in the linear attenuation coefficient for an image of a mouse exposed to 0.25 Gy is obtained with a minimum isotropic voxel size of 135 microm. However, the same COV is achieved at a dose of 5.0 Gy with a 65 microm isotropic voxel size. Conversely, for a 68 mm diameter rat, a COV of 1% obtained from an image at 5.0 Gy would require an isotropic voxel size of 100 microm. These results indicate that short-term, potentially lethal, effects of ionizing radiation will limit high-resolution live animal imaging. As improvements in detector technology allow the resolution to improve, by decreasing the detector element size to tens of microns or less, high quality images will be limited by the x-ray dose administered. For the highest quality images, these doses will approach the lethal dose or LD50 for the animals. Approaching the lethal dose will affect the way experiments are planned, and may reduce opportunities for experiments involving imaging the same animal over time. Dose considerations will become much more important for live small-animal imaging as the limits of resolution are tested.

A simple and practical method of correcting the hysteresis loss in a thin lamination for the effects of minor loops is described. The necessary correction is applied to the losses that would occur under conditions of sinusoidal flux density and the required empirical factor is derived using a broad range of loss measurement data. It is shown that the correction, to a very good approximation, varies linearly with the unweighted algebraic sum of the flux density reversals in the driving waveforms. Used together with a similar factor that corrects the eddy current component of loss for the effects of flux density harmonics, the total loss can be easily estimated to an accuracy of less than 5%.

The classical two-parameter Fourier algorithm for computing synchrophasors is appropriate when the underlying voltage and current waveforms are sinusoids with constant amplitude and phase angle and with a frequency equal to the assumed value. Synchrophasor measurements, however, are applied in power systems to track dynamic conditions where, by definition, currents and voltages, though resembling sine-waves, exhibit changes in their magnitudes and vectorial positions. This paper presents a novel algorithm for estimating synchrophasors under such dynamic conditions. In contrast to the classical Fourier algorithm, our model is a complex Taylor expansion, yielding several parameters in the model to be estimated. Four- and six-parameter models are presented corresponding to first and second order Taylor expansions. This paper derives a compensation method for canceling the error in the classical Fourier algorithm that arises under dynamic conditions, shows comparative simulation and test results and describes an efficient implementation. Application of the error cancellation method to other phasor algorithms and extending the technique to higher order Taylor expansions, are discussed. Implementation of synchrophasor measurements on protection and control intelligent electronic devices (IEDs) is discussed, and solutions are presented that allow for secure integration.

AIMS: Impaired energy metabolism has been implicated in the pathogenesis of heart failure. Hyperpolarized (13)C magnetic resonance (MR), in which (13)C-labelled metabolites are followed using MR imaging (MRI) or spectroscopy (MRS), has enabled non-invasive assessment of pyruvate metabolism. We investigated the hypothesis that if we serially examined a model of heart failure using non-invasive hyperpolarized [(13)C]pyruvate with MR, the profile of in vivo pyruvate oxidation would change throughout the course of the disease. METHODS AND RESULTS: Dilated cardiomyopathy (DCM) was induced in pigs (n = 5) by rapid pacing. Pigs were examined using MR at weekly time points: cine-MRI assessed cardiac structure and function; hyperpolarized [2-(13)C]pyruvate was administered intravenously, and (13)C MRS monitored [(13)C]glutamate production; (31)P MRS assessed cardiac energetics [phosphocreatine (PCr)/ATP]; and hyperpolarized [1-(13)C]pyruvate was administered for MRI of pyruvate dehydrogenase complex (PDC)-mediated pyruvate oxidation via [(13)C]bicarbonate production. Early in pacing, the cardiac index decreased by 25%, PCr/ATP decreased by 26%, and [(13)C]glutamate production decreased by 51%. After clinical features of DCM appeared, end-diastolic volume increased by 40% and [(13)C]bicarbonate production decreased by 67%. Pyruvate dehydrogenase kinase 4 protein increased by two-fold, and phosphorylated Akt decreased by half. Peroxisome proliferator-activated receptor-α and carnitine palmitoyltransferase-1 gene expression decreased by a half and a third, respectively. CONCLUSION: Despite early changes associated with cardiac energetics and (13)C incorporation into the Krebs cycle, pyruvate oxidation was maintained until DCM developed, when the heart's capacity to oxidize both pyruvate and fats was reduced. Hyperpolarized (13)C MR may be important to characterize metabolic changes that occur during heart failure progression.

Chapter 11 Rapid, Accurate Mapping of Soil Salinity by Electromagnetic Ground Conductivity Meters J. Duncan McNeill, J. Duncan McNeill Geonics Limited, Mississauga, OntarioSearch for more papers by this author J. Duncan McNeill, J. Duncan McNeill Geonics Limited, Mississauga, OntarioSearch for more papers by this author Book Editor(s):G. Clarke Topp, G. Clarke ToppSearch for more papers by this authorW. Daniel Reynolds, W. Daniel ReynoldsSearch for more papers by this authorRichard E. Green, Richard E. GreenSearch for more papers by this author First published: 01 January 1992 https://doi.org/10.2136/sssaspecpub30.c11Citations: 8Book Series:SSSA Special Publications AboutPDFPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShareShare a linkShare onFacebookTwitterLinked InRedditWechat Summary The saturated paste extract method is widely accepted as an accurate indication of the degree of salinization of a soil sample. This method basically measures the electrical conductivity of a carefully prepared sample of the soil and, while accurate, is time consuming to carry out because of the preparation procedure. It is also a "point-sample" method, leaving doubt as to whether the measurement is representative. To overcome these limitations extensive investigation into the use of conventional in situ direct current (DC) resistivity techniques has been carried out to determine conditions under which this technique accurately measures the degree of soil salinization. However, conventional DC resistivity measurements are also relatively slow to carry out. Instruments using inductive electromagnetic techniques are now widely used to map terrain conductivity. These devices, which electromagnetically induce small currents in the ground, measure the magnetic field strength generated by these currents to determine terrain conductivity. They are well suited to assessing soil salinity since they respond to more conductive (and thus more saline) soils and, furthermore, do not require electrical contact with the ground. Exploration depth of these devices is determined by the spacing between the transmitter and receiver coils; commercially available instruments measure from a depth of approximately 1 m to several tens of meters. Their chief advantage is that large areas can be surveyed quickly, and thus in considerable detail. A significant disadvantage is that variation of conductivity with depth is not well resolved. Because of various factors other than soil salinity which can affect the bulk soil conductivity, saturated paste extract samples must still be taken, but now at much reduced intervals and at locations now known to be statistically significant. The theory of operation of electromagnetic ground conductivity meters is briefly described, comparative survey results (with both saturation paste extract and DC resistivity measurements) are shown, and survey results over the depth range referred to above are presented. Citing Literature Advances in Measurement of Soil Physical Properties: Bringing Theory into Practice, Volume 30 RelatedInformation

The ketogenic diet (KD), a treatment for drug-resistant epilepsy, elevates brain acetone. Acetone has been shown to suppress experimental seizures. Whether elevation of acetone is the basis of the anticonvulsant effects of the KD and whether acetone, like the KD, antagonizes many different types of seizures, however, is unknown. This study investigated the spectrum of the anticonvulsant effects of acetone in animal seizure models. Rats were injected with acetone intraperitoneally. Dose-response effects were measured in four different models: (1) the maximal electroshock test, which models human tonic-clonic seizures; (2) the subcutaneous pentylenetetrazole test, which models human typical absence seizures; (3) the amygdala kindling test, which models human complex partial seizures with secondary generalization; and (4) the AY-9944 test, which models chronic atypical absence seizures, a component of the Lennox-Gastaut syndrome. Acetone suppressed seizures in all of the models, with the following ED(50)'s (expressed in mmol/kg): maximal electroshock, 6.6; pentylenetetrazole, 9.7; generalized kindled seizures, 13.1; focal kindled seizures, 26.5; AY-9944, 4.0. Acetone appears to have a broad spectrum of anticonvulsant effects. These effects parallel the effects of the KD. Elevation of brain acetone therefore may account for the efficacy of the KD in intractable epilepsy.

Abstract Elevated biological concentrations of methylmercury (MeHg), a bioaccumulative neurotoxin, are observed throughout the Arctic Ocean, but major sources and degradation pathways in seawater are not well understood. We develop a mass budget for mercury species in the Arctic Ocean based on available data since 2004 and discuss implications and uncertainties. Our calculations show that high total mercury (Hg) in Arctic seawater relative to other basins reflect large freshwater inputs and sea ice cover that inhibits losses through evasion. We find that most net MeHg production (20 Mg a −1 ) occurs in the subsurface ocean (20–200 m). There it is converted to dimethylmercury (Me 2 Hg: 17 Mg a −1 ), which diffuses to the polar mixed layer and evades to the atmosphere (14 Mg a −1 ). Me 2 Hg has a short atmospheric lifetime and rapidly degrades back to MeHg. We postulate that most evaded Me 2 Hg is redeposited as MeHg and that atmospheric deposition is the largest net MeHg source (8 Mg a −1 ) to the biologically productive surface ocean. MeHg concentrations in Arctic Ocean seawater are elevated compared to lower latitudes. Riverine MeHg inputs account for approximately 15% of inputs to the surface ocean (2.5 Mg a −1 ) but greater importance in the future is likely given increasing freshwater discharges and permafrost melt. This may offset potential declines driven by increasing evasion from ice‐free surface waters. Geochemical model simulations illustrate that for the most biologically relevant regions of the ocean, regulatory actions that decrease Hg inputs have the capacity to rapidly affect aquatic Hg concentrations.

Reports that exposure to music causes benefits in nonmusical domains have received widespread attention in the mainstream media. Such reports have also influenced public policy. The so-called "Mozart effect" actually refers to two relatively distinct phenomena. One concerns short-term increases in spatial abilities that are said to occur from listening to music composed by Mozart. The other refers to the possibility that formal training in music yields nonmusical benefits. A review of the relevant findings indicates that the short-term effect is small and unreliable. Moreover, when it is evident, it can be explained by between-condition differences in the listener's mood or levels of cognitive arousal. By contrast, the effect of music lessons on nonmusical aspects of cognitive development is still an open question. Several studies have reported positive associations between formal music lessons and abilities in nonmusical (e.g., linguistic, mathematical, and spatial) domains. Nonetheless, compelling evidence for a causal link remains elusive.

Using a whole-watershed approach and a combination of historical, contemporary, modeled and paleolimnological datasets, we show that the High Arctic's largest lake by volume (Lake Hazen) has succumbed to climate warming with only a ~1 °C relative increase in summer air temperatures. This warming deepened the soil active layer and triggered large mass losses from the watershed's glaciers, resulting in a ~10 times increase in delivery of glacial meltwaters, sediment, organic carbon and legacy contaminants to Lake Hazen, a >70% decrease in lake water residence time, and near certainty of summer ice-free conditions. Concomitantly, the community assemblage of diatom primary producers in the lake shifted dramatically with declining ice cover, from shoreline benthic to open-water planktonic species, and the physiological condition of the only fish species in the lake, Arctic Char, declined significantly. Collectively, these changes place Lake Hazen in a biogeochemical, limnological and ecological regime unprecedented within the past ~300 years.

Walking to or from school may provide a regular source of physical activity for children and youth. To improve walking practices among this younger population, urban planners emphasize the importance of built environment interventions. Empirical understanding of the potential relationship between the built environment and active school transportation (e.g., walking) is therefore essential to the development of effective planning interventions. In the nexus of empiricism and policy, place-based differences in school transport policy and urbanization processes, which may associate with mode choice, provide the rationale for conducting local research to support local policy development. This study examines the association between the built environment and the likelihood of walking or being driven to or from school. The research also addresses differences in mode choice behavior across morning and afternoon school trips. Binomial logit models were specified to study the school travel outcomes of children aged 11 to 13 years in the city of Toronto, Canada. Distance between the residence and school had the strongest correlation with mode choice; other built environment measures had moderate associations with walking. Importantly, the built environment around a child's residence had a stronger association with mode choice than did the built environment around the school. Furthermore, the effect of the built environment was more apparent for home-to-school trips. This research provides evidence that the built environment may influence school travel mode choice, but planners and community-based organizations should exercise caution when the nature of interventions required to encourage walking among children is determined.

Abstract The present report is the first phase of an investigation of those variables which control the rate of heat transfer in the air gap of a rotating electrical machine. This phase of the problem reduces to obtaining a basic understanding of the fluid-flow and heat-flow processes in an annulus, formed by two concentric cylinders, with the inner cylinder rotating and with the outer cylinder stationary. The primary independent variables and effects are, first, the axial velocity of the air through the air gap, which is combined with other variables to form the customary Reynolds number; second, the speed of rotation, which is combined with other variables to form a new dimensionless group, called the Taylor number, in honor of G. I. Taylor, who laid the theoretical and experimental foundations for this problem; third, the temperature gradients at the walls; fourth, the surface roughness in the air gap; and finally, the “entrance effects” introduced by the development of the boundary-layer flow in the air gap. The present report gives the experimental results obtained for two smooth and long annuli, thereby eliminating from consideration, at present, the last two effects given above. It is shown that four distinct modes of flow exist for adiabatic and diabatic flow of air in these annuli. The demarcation lines of these flow regions were investigated in detail for adiabatic flow with hot-wire anemometers and also by means of visual and photographic methods. The results showed that four modes of flow exist over regions of Reynolds number and Taylor number for both adiabatic and diabatic flow. These modes are: 1 purely laminar flow; 2 laminar flow plus Taylor vortexes; 3 purely turbulent flow; 4 turbulent flow plus vortexes. The results obtained here for adiabatic flow were found to agree well with the work of Cornish for the boundary line between the regions of laminar flow and laminar-plus-vortexes flow, but they did not agree with similar results by Fage. Preliminary results are also presented here for diabatic flow in the annulus in the form of heat-transfer coefficients. These results are shown in the form of a three-dimensional surface in which the Nusselt number is represented as a function of the Reynolds number and Taylor number.

Obtaining three-dimensional geometrical data of vascular systems is of major importance to a number of research areas in medicine and biology. Examples are the characterization of tumor vasculature, modeling blood flow, or genetic effects on vascular development. The performance of the General Electric Medical Systems MS8 microCT scanner is examined in the context of these applications. The system is designed to acquire high-resolution images of specimens up to 5 cm in diameter. A maximum resolution of 38 lp/mm at the 10% modulation transfer function level or 22 microm full width at half maximum of the plane spread function can be achieved with 8.5 microm voxels and a 17 mm field of view. Three different contrast agents are discussed and applied for imaging of small animal vasculature: corrosion casting material Batson's No. 17 with an added lead pigment, silicon rubber MICROFIL MV122, and a suspension of barium sulfate (Baritop) in gelatin. Contrast for all of these agents was highly variable in different vessels as well as within the same vessel. Imaging of PMMA tubing filled with MICROFIL shows that even vessels below 20 microm in diameter are detectable and that diameter estimation of vessels based on thresholding is possible with a precision of 2-3 pixels.

One of the challenges of optimizing signal-to-noise ratio (SNR) and image quality in (13)C metabolic imaging using hyperpolarized (13)C-pyruvate is associated with the different MR signal time-courses for pyruvate and its metabolic products, lactate and alanine. The impact of the acquisition time window, variation of flip angles, and order of phase encoding on SNR and image quality were evaluated in mathematical simulations and rat experiments, based on multishot fast chemical shift imaging (CSI) and three-dimensional echo-planar spectroscopic imaging (3DEPSI) sequences. The image timing was set to coincide with the peak production of lactate. The strategy of combining variable flip angles and centric phase encoding (cPE) improved image quality while retaining good SNR. In addition, two aspects of EPSI sampling strategies were explored: waveform design (flyback vs. symmetric EPSI) and spectral bandwidth (BW = 500 Hz vs. 267 Hz). Both symmetric EPSI and reduced BW trended toward increased SNR. The imaging strategies reported here can serve as guidance to other multishot spectroscopic imaging protocols for (13)C metabolic imaging applications.

Individuals differ in musical competence, which we defined as the ability to perceive, remember, and discriminate sequences of tones or beats. We asked whether such differences could be explained by variables other than music training, including socioeconomic status (SES), short-term memory, general cognitive ability, and personality. In a sample of undergraduates, musical competence had positive simple associations with duration of music training, SES, short-term memory, general cognitive ability, and openness-to-experience. When these predictors were considered jointly, musical competence had positive partial associations with music training, general cognitive ability, and openness. Nevertheless, moderation analyses revealed that the partial association between musical competence and music training was evident only among participants who scored below the mean on our measure of general cognitive ability. Moreover, general cognitive ability and openness had indirect associations with musical competence by predicting music training, which in turn predicted musical competence. Musical competence appears to be the result of multiple factors, including but not limited to music training.

BACKGROUND: Active school transport (AST), school travel using an active mode like walking, may be important to children's overall physical activity. A "school travel plan" (STP) documents a school's transport characteristics and provides an action plan to address school and neighborhood barriers to AST. METHODS: We conducted a pilot STP intervention at 12 schools in 4 Canadian provinces. Facilitators and school personnel created and implemented AST action plans. Parent's self-reports (N = 1489) were the basis for evaluating the intervention. A content analysis identified type, frequency, and perceived success of initiatives. RESULTS: School travel plans emphasized education and promotion, and AST activities and events. Capital improvement projects were more common at schools in older suburban neighborhoods, whereas enforcement was more common at schools in newer suburban neighborhoods. Rates of active transportation increased from 43.8% to 45.9%. At follow-up, 13.3% of households reported less driving. Parents/caregivers cited weather, convenience, and trip chaining as primary reasons for continued driving. CONCLUSION: The STP process may facilitate changes to patterns of school travel. An STP can expand a school's capacity to address transportation issues through mobilization of diverse community resources. Future STP initiatives may benefit from addressing convenience, safety through enforcement, and by examining how schools can be supported in implementing infrastructure improvements.