308 research outputs found
Solving Bit-Vector Equations of Fixed and Non-Fixed Size
This report is concerned with solving equations on fixed andnon-fixed size bit-vector terms. We define an equational transformationsystem for solving equations on terms where all sizes ofbit-vectors and extraction positions are known. This transformationsystem suggests a generalization for dealing with bit-vectorsof unknown size and unknown extraction positions. Both solversadhere to the principle of splitting bit-vectors only on demand,thereby making them quite effective in practice
Reduction of myocardial infarction by calpain inhibitors A-705239 and A-705253 in isolated perfused rabbit hearts
Two novel calpain inhibitors (A-705239 and A-705253) were studied in isolated perfused rabbit hearts subjected to 60-min occlusion of the ramus interventricularis of the left coronary artery (below the origin of the first diagonal branch), followed by 120 min of reperfusion. The inhibitors were added to the perfusion fluid in various final concentrations from the beginning of the experiments before the coronary artery was blocked. Hemodynamic monitoring and biochemical analysis of perfusion fluid from the coronary outflow were carried out. Myocardial infarct size and the area at risk (transiently non-perfused myocardium) were determined from left ventricular slices after a special staining procedure with Evans blue and 2,3,5-triphenyltetrazolium chloride. The infarcted area (dead myocardium) was 77.9 +/- 2.3% of the area at risk in untreated controls (n=12). The infarct size was significantly reduced in the presence of both calpain inhibitors. The best effect was achieved with 10(-8) m A-705253 (n=8), which reduced (p<0.001) the infarcted area to 49.3 +/- 3.9% of the area at risk, corresponding to an infarct reduction of 61.8%. No statistical difference was observed between the experimental groups in coronary perfusion, left ventricular pressure, and in the release of lactate dehydrogenase and creatine kinase from heart muscle
Wirtschaftlichkeit von Grünguthäcksel: Eine risikoorientierte Systembewertung
The enhancement and improvement of soil fertility is one of the principal aims of or-ganic agriculture. The practical realization needs a multi-annual, complex approach as well as the economic valuation. Exemplarily, it is shown for the use of green chop with wide C/N ratio in field beans. The cost-benefits-analysis is done with results from field trials and data from real farms. It includes the yield effects on beans and the following grain. Additional impacts like weed suppression and nitrogen fixation are estimated, too. The results show that the gross margin difference for beans is averaged 27 to 55 €/ha (depending on application techniques), but for grains +176 €/ha. Overall, the farms can gain +1 to +13 €/ha in average by using green chop to improve soil fertility. A risk analysis regarding yield variability of beans and grains shows a surplus for farms in 70 to 75 % of cases
Monetäre Auswirkungen angepassten Reifeninnendrucks im Ackerbau unter besonderer Berücksichtigung der Erbsen
A goal in ecological agriculture is to avoid and reduce soil compaction. One possibility is the use of a tire inflation system (TIS). Additionally, sowing equipment with broader working width can be used. Both technologies save working time and fuel. Furthermore, yield could increase due to less soil compaction, especially for peas as field trials show. Data from the field trials and from original farms were used to calculate the profitability for the soil protection technologies. The fuel savings are enough to cover the variable and fix costs of the TIS. The pea surplus is an extra revenue. If working time reduction is additionally valued than in total the farms can gain above 19,-€/ha arable land using a TIS. The most farms have not enough traction power for broader sowers. If it exists the gain is about 26 €/ha arable land. The gain is mostly enough for the amortization of the TIS. For sowers with broader working width the amortization is only given if there is not a combined cultivation machine or it is at least a cheap one
Wintererbsenanbau: Ökonomische Aspekte für Praxisbetriebe
The use of winter peas becomes more and more common in organic agriculture. In field trials, winter pea-triticale intercrops were compared with spring peas concerning their yield performance. The differences in gross margins were calculated by using data from origin farms. Savings in seed costs (-136 €/ha) and machine costs (-13 €/ha) could be gained by replacing spring pea sole crops with winter pea-triticale intercrops. Additionally, there were yield increases of 33 % for intercropped winter peas, which resulted in an extra benefit of 378 €/ha. Aside from that, the intercropped triticale provides an extra income
Retinotopic Activation in Response to Subjective Contours in Primary Visual Cortex
Objects in our visual environment are arranged in depth and hence there is a considerable amount of overlap and occlusion in the image they generate on the retina. In order to properly segment the image into figure and background, boundary interpolation is required even across large distances. Here we study the cortical mechanisms involved in collinear contour interpolation using fMRI. Human observers were asked to discriminate the curvature of interpolated boundaries in Kanizsa figures and in control configurations, which contained identical physical information but did not generated subjective shapes. We measured a spatially precise spin-echo BOLD signal and found stronger responses to subjective shapes than non-shapes at the subjective boundary locations, but not at the inducer locations. The responses to subjective contours within primary visual cortex were retinotopically specific and analogous to that to real contours, which is intriguing given that subjective and luminance-defined contours are physically fundamentally different. We suggest that in the absence of retinal stimulation, the observed activation changes in primary visual cortex are driven by intracortical interactions and feedback, which are revealed in the absence of a physical stimulus
Macromolecular background signal and non-Gaussian metabolite diffusion determined in human brain using ultra-high diffusion weighting.
PURPOSE
Definition of a macromolecular MR spectrum based on diffusion properties rather than relaxation time differences and characterization of non-Gaussian diffusion of brain metabolites with strongly diffusion-weighted MR spectroscopy.
METHODS
Short echo time MRS with strong diffusion-weighting with b-values up to 25 ms/μm2 at two diffusion times was implemented on a Connectom system and applied in combination with simultaneous spectral and diffusion decay modeling. Motion-compensation was performed with a combined method based on the simultaneously acquired water and a macromolecular signal.
RESULTS
The motion compensation scheme prevented spurious signal decay reflected in very small apparent diffusion constants for macromolecular signal. Macromolecular background signal patterns were determined using multiple fit strategies. Signal decay corresponding to non-Gaussian metabolite diffusion was represented by biexponential fit models yielding parameter estimates for human gray matter that are in line with published rodent data. The optimal fit strategies used constraints for the signal decay of metabolites with limited signal contributions to the overall spectrum.
CONCLUSION
The determined macromolecular spectrum based on diffusion properties deviates from the conventional one derived from longitudinal relaxation time differences calling for further investigation before use as experimental basis spectrum when fitting clinical MR spectra. The biexponential characterization of metabolite signal decay is the basis for investigations into pathologic alterations of microstructure
Rs9939609 Variant of the Fat Mass and Obesity-Associated Gene and Trunk Obesity in Adolescents
A common T/A polymorphism (rs9939609) in the fat mass and obesity associated (FTO) gene was found associated with early-onset and severe obesity in both adults and children. However, recent observations failed to find associations of FTO with obesity. To investigate the genetic background of early obesity, we analysed the single nucleotide polymorphism (SNP) rs9939609 of FTO in 371 styrian adolescents towards degree of obesity, subcutaneous adipose tissue (SAT)-distribution determined by lipometry, early metabolic and preatherosclerotic symptoms. The percentage of AA homozygotes for the rs9939609 SNP of FTO was significantly increased in the obese adolescents. Compared to the TT wildtype, AA homozygotes showed significantly elevated values of SAT thickness at the trunk-located lipometer measure points neck and frontal chest, body weight, body mass index, waist, and hip circumference. No associations were found with carotis communis intima media thickness, systolic, diastolic blood pressure, ultrasensitive C-reactive protein (US-CRP), homocystein, total cholesterol, triglycerides, HDL cholesterol, oxidized LDL, fasted glucose, insulin, HOMA-index, liver transaminases, uric acid, and adipokines like resistin, leptin, and adiponectin. Taken together, to the best of our knowledge we are the first to report that the rs9939609 FTO SNP is associated with trunk weighted obesity as early as in adolescence
Cortical lamina-dependent blood volume changes in human brain at 7T
Cortical layer-dependent high (sub-millimeter) resolution functional magnetic resonance imaging (fMRI) in human or animal brain can be used to address questions regarding the functioning of cortical circuits, such as the effect of different afferent and efferent connectivities on activity in specific cortical layers. The sensitivity of gradient echo (GE) blood oxygenation level-dependent (BOLD) responses to large draining veins reduces its local specificity and can render the interpretation of the underlying laminar neural activity impossible. The application of the more spatially specific cerebral blood volume (CBV)-based fMRI in humans has been hindered by the low sensitivity of the noninvasive modalities available. Here, a vascular space occupancy (VASO) variant, adapted for use at high field, is further optimized to capture layer-dependent activity changes in human motor cortex at sub-millimeter resolution. Acquired activation maps and cortical profiles show that the VASO signal peaks in gray matter at 0.8–1.6 mm depth, and deeper compared to the superficial and vein-dominated GE-BOLD responses. Validation of the VASO signal change versus well-established iron-oxide contrast agent based fMRI methods in animals showed the same cortical profiles of CBV change, after normalization for lamina-dependent baseline CBV. In order to evaluate its potential of revealing small lamina-dependent signal differences due to modulations of the input-output characteristics, layer-dependent VASO responses were investigated in the ipsilateral hemisphere during unilateral finger tapping. Positive activation in ipsilateral primary motor cortex and negative activation in ipsilateral primary sensory cortex were observed. This feature is only visible in high-resolution fMRI where opposing sides of a sulcus can be investigated independently because of a lack of partial volume effects. Based on the results presented here, we conclude that VASO offers good reproducibility, high sensitivity and lower sensitivity than GE-BOLD to changes in larger vessels, making it a valuable tool for layer-dependent fMRI studies in humans
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