583 research outputs found

    The Construct of Personality and Hemispheric Usage

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    Studies on the differential contributions of the cerebral hemispheres to human experience and behavior have demonstrated that the hemispheres are lateralized for cognitive strategies and, possibly, for emotional valance. Recently researchers have demonstrated that the hemispheres may also be lateralized for certain personality disorders and personality traits. Using lateral eye movements as a measure of hemispheric activation, Dawson, Tucker, and Swenson (in preparation) have shown that certain self-description questionnaires may serve to discriminate subjects who characteristically utilize one hemisphere over the other, regardless of the relative adaptiveness of the cognitive strengths of that hemisphere for the task at hand. This study replicated the findings of the Dawson et al. study, using brain wave activity as an index of lateralized activation. Separating subjects on the basis of their scores on self-description personality measures, it was discovered that subjects who were unrealistically favorable in their self-descriptions (deniers) evidenced greater right hemisphere activation, regardless of the task being performed. Subjects who were overly critical in their self-descriptions (critics) evidenced symmetrical hemispheric activation with a tendency toward greater left hemispheric activation, particularly evident during the baseline and spatial tasks. These findings were evidenced in both the theta and alpha bands for average power, with comparisons in the theta band demonstrating the clearest personality related effects. Analyses on coherence data were performed and described without interpretation. The results of this study were used to provide support for a theory of hemispheric personality. A model is built on the research findings on lateralized cognition and then extended to address some of the recent controversies in the lateralization literature. Implications for further research are discussed and suggestions of how such a model might be used in psychological/medical treatment and diagnoses are discussed

    Feeding Techniques To Increase Calf Growth In The First Two Months Of Life

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    End of project reportData from Cornell University and the University of Illinois in the USA suggested that average daily liveweight gains of 900 to 1000 g/calf/day could be achieved from birth to weaning provided the calf milk replacer (CMR) is formulated to meet the calf’s amino acid requirements for such a rate of gain. Their findings suggested a daily milk replacer DM allowance of 1250 to 1500 g/d with a crude protein content of 26 to 30%. A series of studies were undertaken, at ARINI with home born dairy calves and at Grange Beef Research Centre with purchased dairy calves, to determine the effect of increasing the daily milk replacer DM allowance and or increasing the crude protein content of the CMR on calf performance.The main outcomes of these studies were There was no growth or intake response in any of the studies to increasing the crude protein content of the CMP from 23% to 28%. Calf growth rates responded to increasing the dailymilk replacer allowance from 600 to 1200 g/day for both home bred and purchased calves. However, the effect was not significant post-weaning in any of the studies. In all of the studies (for both home reared and purchased calves) feeding a high level of CMRdecreased concentrate DM intake. However, the calves concentrate intakes were similar post-weaning. The home bred calves with free access to the milk replacer feeders failed to consume their 1200 g/day allowance. Calves offered 600 or 1200 g of CMR/day had average consumption of 554 and 944 g/d, respectively, in the milk feeding period. Feeding a high (1200 g/d) compared to a low level (600 g/d) CMRdiet for the first 56 days had no significant effect on carcass weight or carcass characteristics when purchased male calves were slaughtered off an ad libitum concentrate diet after 388 days. The final carcass weights were 231 and 240 kg for the respective 600 and 1200 g/d CMR. Reducing the fat content of the CMRfrom 18% to 12% did not have any effect on concentrate intake or liveweight gain

    State-space model identification and feedback control of unsteady aerodynamic forces

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    Unsteady aerodynamic models are necessary to accurately simulate forces and develop feedback controllers for wings in agile motion; however, these models are often high dimensional or incompatible with modern control techniques. Recently, reduced-order unsteady aerodynamic models have been developed for a pitching and plunging airfoil by linearizing the discretized Navier-Stokes equation with lift-force output. In this work, we extend these reduced-order models to include multiple inputs (pitch, plunge, and surge) and explicit parameterization by the pitch-axis location, inspired by Theodorsen's model. Next, we investigate the na\"{\i}ve application of system identification techniques to input--output data and the resulting pitfalls, such as unstable or inaccurate models. Finally, robust feedback controllers are constructed based on these low-dimensional state-space models for simulations of a rigid flat plate at Reynolds number 100. Various controllers are implemented for models linearized at base angles of attack α0=0∘,α0=10∘\alpha_0=0^\circ, \alpha_0=10^\circ, and α0=20∘\alpha_0=20^\circ. The resulting control laws are able to track an aggressive reference lift trajectory while attenuating sensor noise and compensating for strong nonlinearities.Comment: 20 pages, 13 figure

    Pulmonary arterial remodeling revealed by microfocal x-ray tomography

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    Animal models and micro-CT imaging are useful for understanding the functional consequences of, and identifying the genes involved in, the remodeling of vascular structures that accompanies pulmonary vascular disease. Using a micro-CT scanner to image contrast-enhanced arteries in excised lungs from fawn hooded rats (a strain genetically susceptible to hypoxia induced pulmonary hypertension), we found that portions of the pulmonary arterial tree downstream from a given diameter were morphometrically indistinguishable. This \u27self-consistency\u27 property provided a means for summarizing the pulmonary arterial tree architecture and mechanical properties using a parameter vector obtained from measurements of the contiguous set of vessel segments comprising the longest (principal) pathway and its branches over a range of vascular pressures. This parameter vector was used to characterize the pulmonary vascular remodeling that occurred in rats exposed to a hypoxic (11.5% oxygen) environment and provided the input to a hemodynamic model relating structure to function. The major effect of the remodeling was a longitudinally (pulmonary artery to arterioles) uniform decrease in vessel distensibility that resulted in a 90% increase in arterial resistance. Despite the almost uniform change in vessel distensibility, over 50% of the resistance increase was attributable to vessels with unstressed diameters less than 125 microns

    Micro-CT Image-Derived Metrics Quantify Arterial Wall Distensibility Reduction in a Rat Model of Pulmonary Hypertension

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    We developed methods to quantify arterial structural and mechanical properties in excised rat lungs and applied them to investigate the distensibility decrease accompanying chronic hypoxia-induced pulmonary hypertension. Lungs of control and hypertensive (three weeks 11% O2) animals were excised and a contrast agent introduced before micro-CT imaging with a special purpose scanner. For each lung, four 3D image data sets were obtained, each at a different intra-arterial contrast agent pressure. Vessel segment diameters and lengths were measured at all levels in the arterial tree hierarchy, and these data used to generate features sensitive to distensibility changes. Results indicate that measurements obtained from 3D micro-CT images can be used to quantify vessel biomechanical properties in this rat model of pulmonary hypertension and that distensibility is reduced by exposure to chronic hypoxia. Mechanical properties can be assessed in a localized fashion and quantified in a spatially-resolved way or as a single parameter describing the tree as a whole. Micro-CT is a nondestructive way to rapidly assess structural and mechanical properties of arteries in small animal organs maintained in a physiological state. Quantitative features measured by this method may provide valuable insights into the mechanisms causing the elevated pressures in pulmonary hypertension of differing etiologies and should become increasingly valuable tools in the study of complex phenotypes in small-animal models of important diseases such as hypertension

    Quantification of Bronchial Circulation Perfusion in Rats

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    The bronchial circulation is thought to be the primary blood supply for pulmonary carcinomas. Thus, we have developed a method for imaging and quantifying changes in perfusion in the rat lung due to development of the bronchial circulation. A dual-modality micro-CT/SPECT system was used to detect change in perfusion in two groups of rats: controls and those with a surgically occluded left pulmonary artery. Both groups were imaged following injections on separate days i) 2mCi of Tc99m labeled macroaggregated albumin (MAA) into the left carotid artery (IA) and ii) a similar injection into the femoral vein (IV). The IA injection resulted in Tc99m accumulation in capillaries of the systemic circulation including the bronchial circulation, whereas the IV resulted in Tc99m accumulation in the pulmonary capillaries. Ordered subset expectation maximization (OSEM) was used to reconstruct the SPECT image volumes and a Feldkamp algorithm was used to reconstruct the micro-CT image volumes. The micro-CT and SPECT volumes were registered, the SPECT image volume was segmented using the right and left lung boundaries defined from the micro-CT volume, and the ratio of IA radioactivity accumulation in the left lung to IV radioactivity accumulation in both lungs was used as a measure of left lung flow via the bronchial circulation. This ratio was ~0.02 for the untreated rats compared to the treated animals that had an increased flow ratio of ~0.21 40 days after left pulmonary artery occlusion. This increase in flow to the occluded left lung via the bronchial circulation suggests this will be a useful model for further investigating antiangiogenic treatments

    Quantification of Bronchial Circulation Perfusion in Rats

    Get PDF
    The bronchial circulation is thought to be the primary blood supply for pulmonary carcinomas. Thus, we have developed a method for imaging and quantifying changes in perfusion in the rat lung due to development of the bronchial circulation. A dual-modality micro-CT/SPECT system was used to detect change in perfusion in two groups of rats: controls and those with a surgically occluded left pulmonary artery. Both groups were imaged following injections on separate days i) 2mCi of Tc99m labeled macroaggregated albumin (MAA) into the left carotid artery (IA) and ii) a similar injection into the femoral vein (IV). The IA injection resulted in Tc99m accumulation in capillaries of the systemic circulation including the bronchial circulation, whereas the IV resulted in Tc99m accumulation in the pulmonary capillaries. Ordered subset expectation maximization (OSEM) was used to reconstruct the SPECT image volumes and a Feldkamp algorithm was used to reconstruct the micro-CT image volumes. The micro-CT and SPECT volumes were registered, the SPECT image volume was segmented using the right and left lung boundaries defined from the micro-CT volume, and the ratio of IA radioactivity accumulation in the left lung to IV radioactivity accumulation in both lungs was used as a measure of left lung flow via the bronchial circulation. This ratio was ~0.02 for the untreated rats compared to the treated animals that had an increased flow ratio of ~0.21 40 days after left pulmonary artery occlusion. This increase in flow to the occluded left lung via the bronchial circulation suggests this will be a useful model for further investigating antiangiogenic treatments

    Entanglement and the Power of One Qubit

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    The "Power of One Qubit" refers to a computational model that has access to only one pure bit of quantum information, along with n qubits in the totally mixed state. This model, though not as powerful as a pure-state quantum computer, is capable of performing some computational tasks exponentially faster than any known classical algorithm. One such task is to estimate with fixed accuracy the normalized trace of a unitary operator that can be implemented efficiently in a quantum circuit. We show that circuits of this type generally lead to entangled states, and we investigate the amount of entanglement possible in such circuits, as measured by the multiplicative negativity. We show that the multiplicative negativity is bounded by a constant, independent of n, for all bipartite divisions of the n+1 qubits, and so becomes, when n is large, a vanishingly small fraction of the maximum possible multiplicative negativity for roughly equal divisions. This suggests that the global nature of entanglement is a more important resource for quantum computation than the magnitude of the entanglement.Comment: 22 pages, 4 figure

    Modeling and Analysis of Interactions in Virtual Enterprises

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    Advances in computer networking technology and open system standards are making the creation and management of virtual enterprises feasible. A virtual enterprise is a temporary consortium of autonomous, diverse, and possibly geographically dispersed organizations that pool their resources to meet short-term objectives and exploit fastchanging market trends. For a virtual enterprise to succeed, its business processes must be automated, and its startup costs must be minimized. In this paper we describe a formal framework for modeling and reasoning about interactions in a virtual enterprise. Such a framework will form the basis for tools that provide automated support for creation and operation of virtual enterprises. 1

    Dust-Gas Scaling Relations and OH Abundance in the Galactic ISM

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    Observations of interstellar dust are often used as a proxy for total gas column density NHN_\mathrm{H}. By comparing Planck\textit{Planck} thermal dust data (Release 1.2) and new dust reddening maps from Pan-STARRS 1 and 2MASS (Green et al. 2018), with accurate (opacity-corrected) HI column densities and newly-published OH data from the Arecibo Millennium survey and 21-SPONGE, we confirm linear correlations between dust optical depth τ353\tau_{353}, reddening E(B−V)E(B{-}V) and the total proton column density NHN_\mathrm{H} in the range (1−-30)×\times1020^{20}cm−2^{-2}, along sightlines with no molecular gas detections in emission. We derive an NHN_\mathrm{H}/E(B−V)E(B{-}V) ratio of (9.4±\pm1.6)×\times1021^{21}cm−2^{-2}mag−1^{-1} for purely atomic sightlines at ∣b∣|b|>>5∘^{\circ}, which is 60%\% higher than the canonical value of Bohlin et al. (1978). We report a ∼\sim40%\% increase in opacity σ353\sigma_{353}=τ353\tau_{353}/NHN_\mathrm{H}, when moving from the low column density (NHN_\mathrm{H}<<5×\times1020^{20}cm−2^{-2}) to moderate column density (NHN_\mathrm{H}>>5×\times1020^{20}cm−2^{-2}) regime, and suggest that this rise is due to the evolution of dust grains in the atomic ISM. Failure to account for HI opacity can cause an additional apparent rise in σ353\sigma_{353}, of the order of a further ∼\sim20%\%. We estimate molecular hydrogen column densities NH2N_{\mathrm{H}_{2}} from our derived linear relations, and hence derive the OH/H2_2 abundance ratio of XOHX_\mathrm{OH}∼\sim1×\times10−7^{-7} for all molecular sightlines. Our results show no evidence of systematic trends in OH abundance with NH2N_{\mathrm{H}_{2}} in the range NH2N_{\mathrm{H}_{2}}∼\sim(0.1−-10)×\times1021^{21}cm−2^{-2}. This suggests that OH may be used as a reliable proxy for H2_2 in this range, which includes sightlines with both CO-dark and CO-bright gas.Comment: The revised manuscript is accepted for publication in The Astrophysical Journa
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