2,742 research outputs found
Capon- and APES-Based SAR Processing: Performance and Practical Considerations
No full textThis paper discusses the use of Capon's minimum-variance method (MVM) and Amplitude and Phase EStimation (APES) spectral-estimation algorithms to synthetic aperture radar range�azimuth focusing. The rationale of the algorithms is discussed. An implementation of a Capon or APES processing chain is explained, and processing parameters such as chip-image size, resampling factor, and diagonal loading are discussed. For multichannel cases, a joint-processing approach is presented. A set of Monte Carlo simulations are described and used to benchmark Capon- and APES-based processing against conventional matched-filter-based approaches. Both methods improve the resolution and reduce sidelobes. APES yields generally better estimates of amplitude and phase than Capon but with worse resolution. Results with RADARSAT-2 quad-polarization data over Barcelona are used to qualitatively study the real-life performance of these algorithms
Tau binding protein CAPON induces tau aggregation and neurodegeneration
No full textTo understand the molecular processes that link Aβ amyloidosis, tauopathy and neurodegeneration, we screened for tau-interacting proteins by immunoprecipitation/LC-MS. We identified the carboxy-terminal PDZ ligand of nNOS (CAPON) as a novel tau-binding protein. CAPON is an adaptor protein of neuronal nitric oxide synthase (nNOS), and activated by the N-methyl-D-aspartate receptor. We observed accumulation of CAPON in the hippocampal pyramidal cell layer in the AppNL-G-F -knock-in (KI) brain. To investigate the effect of CAPON accumulation on Alzheimer’s disease (AD) pathogenesis, CAPON was overexpressed in the brain of AppNL-G-F mice crossbred with MAPT (human tau)-KI mice. This produced significant hippocampal atrophy and caspase3-dependent neuronal cell death in the CAPON-expressing hippocampus, suggesting that CAPON accumulation increases neurodegeneration. CAPON expression also induced significantly higher levels of phosphorylated, oligomerized and insoluble tau. In contrast, CAPON deficiency ameliorated the AD-related pathological phenotypes in tauopathy model. These findings suggest that CAPON could be a druggable AD target.journal articl
Persistent scatterer densification through the application of capon- And APES-Based SAR reprocessing algorithms
No full textCapon's minimum-variance method (MVM) and amplitude and phase estimation (APES) spectral estimation algorithms can be applied to synthetic aperture radar (SAR) processing to improve the resolution and suppress sidelobe levels. In this paper, we use Capon-/APES-based SAR reprocessing algorithms to increase the persistent scatterer (PS) density in PS interferometry (PSI). We propose a PS candidate (PSC) selection algorithm applicable to the superresolution reprocessed images and the corresponding processing chain. The performance of the proposed algorithm is evaluated by a number of simulations and a stack of TerraSAR-X data. The results show that the Capon algorithm outperforms others in PSC selection. We present a full PSI time-series analysis on the PSCs extracted from the Capon-reprocessed stacks. The results show that the PS density is increased between 50% and 60%, while their interferometric quality is maintained.Mathematical Geodesy and Positionin
The Capon-Bartlett Cross Spectrum Resolution Study
No full textabstract: Power spectral analysis is a fundamental aspect of signal processing used in the detection and \\estimation of various signal features. Signals spaced closely in frequency are problematic and lead analysts to miss crucial details surrounding the data. The Capon and Bartlett methods are non-parametric filterbank approaches to power spectrum estimation. The Capon algorithm is known as the "adaptive" approach to power spectrum estimation because its filter impulse responses are adapted to fit the characteristics of the data. The Bartlett method is known as the "conventional" approach to power spectrum estimation (PSE) and has a fixed deterministic filter. Both techniques rely on the Sample Covariance Matrix (SCM). The first objective of this project is to analyze the origins and characteristics of the Capon and Bartlett methods to understand their abilities to resolve signals closely spaced in frequency. Taking into consideration the Capon and Bartlett's reliance on the SCM, there is a novelty in combining these two algorithms using their cross-coherence. The second objective of this project is to analyze the performance of the Capon-Bartlett Cross Spectra. This study will involve Matlab simulations of known test cases and comparisons with approximate theoretical predictions
Fast Implementation of Two-Dimensional APES and CAPON Spectral Estimators
No full textThe matched-filterbank spectral estimators APES and CAPON have recently received considerable attention in a number of applications. Unfortunately, their computational complexity tends to limit their usage in several cases – a problem that has previously been addressed by different authors. In this paper, we introduce a novel approach to the computation of the APES and CAPON spectra, which leads to a computational method that is considerably faster than all existing techniques. The new implementations of APES and CAPON are called fast APES and fast CAPON, respectively, and are developed for the two-dimensional case, with the one-dimensional case as a special case. Numerical examples are provided to demonstrate the application of APES to synthetic aperture radar (SAR) imaging, and to illustrate the reduction in computational complexity provided by our method.</p
Fast implementation of two-dimensional APES and CAPON spectral estimators
No full textThe matched-filterbank spectral estimators APES and CAPON have received considerable attention in a number of applications. Unfortunately, their computational complexity tends to limit their usage in several cases-a problem that has previously been addressed by different authors. In this paper, we introduce a novel method to the computation of the 1D and 2D APES and CAPON spectra, which is considerably faster than all existing techniques. Numerical examples are provided to demonstrate the application of APES to synthetic aperture radar (SAR) imaging, and to illustrate the reduction in computational complexity provided by our implementation.</p
Dexras1 A G Protein Specifically Coupled to Neuronal Nitric Oxide Synthase via CAPON
No full textAbstractBecause nitric oxide (NO) is a highly reactive signaling molecule, chemical inactivation by reaction with oxygen, superoxide, and glutathione competes with specific interactions with target proteins. NO signaling may be enhanced by adaptor proteins that couple neuronal NO synthase (nNOS) to specific target proteins. Here we identify a selective interaction of the nNOS adaptor protein CAPON with Dexras1, a brain-enriched member of the Ras family of small monomeric G proteins. We find that Dexras1 is activated by NO donors as well as by NMDA receptor–stimulated NO synthesis in cortical neurons. The importance of Dexras1 as a physiologic target of nNOS is established by the selective decrease of Dexras1 activation, but not H-Ras or four other Ras family members, in the brains of mice harboring a targeted genomic deletion of nNOS (nNOS−/−). We also find that nNOS, CAPON, and Dexras1 form a ternary complex that enhances the ability of nNOS to activate Dexras1. These findings identify Dexras1 as a novel physiologic NO effector and suggest that anchoring of nNOS to specific targets is a mechanism by which NO signaling is enhanced
Argumentation in Legal Reasoning
No full textWe will review systems that can store conflicting interpretations and that can propose alternative solutions to a case based on these interpretations. We will also describe systems that can use legal precedents to generate arguments by drawing analogies to or distinguishing precedents. We will discuss systems that can argue why a rule should not be applied to a case even though all its conditions are met. Then there are systems that can act as a mediator between disputing parties by structuring and recording their arguments and responses. Finally we look at systems that suggest mechanisms and tactics for forming arguments.
Much of the work described here is still research: the implemented systems are prototypes rather than finished systems, and much work has not yet reached the stage of a computer program but is stated as a formal theory. Our aim is therefore to give a flavour (certainly not a complete survey) of the variety of research that is going on and the applications that might result in the not too distant future. Also for this reason we will informally paraphrase example inputs and outputs of systems rather than displaying them in their actual, machine-readable format; moreover, because of space limitations the examples have to be kept simple
A single strand conformation polymorphism-based carrier test for spinal muscular atrophy.
No full textSpinal muscular atrophy (SMA) is an autosomal recessive disorder with a newborn prevalence of 1 in 10,000, and a carrier frequency of 1 in 40-60 individuals. The SMA locus has been mapped to chromosome 5q11.2-13. The disease is caused by a deletion of the SMN gene, often encompassing other genes and microsatellite markers. The SMN gene is present in two highly homologous copies, SMN1 and SMN2, differing at five nucleotide positions. Only homozygous SMN1 mutations cause the disease. The sequence similarity between the SMN1 and SMN2 genes can make molecular diagnosis and carrier identification difficult. We developed a sensitive and reliable molecular test for SMN1 carrier identification, by setting up a nonradioactive single strand conformation polymorphism (SSCP)-based method, which allows for the quantification of the amount of the SMN1 gene product with respect to a control gene. The assay was validated in 56 obligate (ascertained) carriers and 20 (ascertained) noncarriers. The sensitivity of the test is 96.4%, and its specificity, 98%. In addition, 6 of 7 SMA patients without homozygous deletions presented with a heterozygous deletion, suggesting a concomitant undetected point mutation on the nondeleted SMN1 allele. Therefore, the present test is effective for detecting compound hemizygote patients, for testing carriers in SMA families, and for screening for SMA heterozygotes in the general population
Slaughter indicators and meat quality of capon
No full textCilj ovog rada bio je utvrditi uzgojne i klaoničke pokazatelje te svojstva kakvoće mesa kopuna u odnosu na pjetliće i pilenkei istog hibrida. Za potrebe istraživanja nabavljeno je 77 jednodnevnih pilića teške hibridne linije Sasso R9. U dobi od 28 dana izvršen je zahvat kastracije. Pilići su nakon zahvata razvrstani u tri skupine: kopune, pjetliće te pilenke. Provedena su dva klanja, prvo u dobi od 90 dana te drugo, u dobi od 140 dana. U dobi od 90 dana, najbolje tovne sposobnosti uočene su kod pjetlića izuzev konverzije hrane. Nakon prvog klanja prosječna masa trupa bila je najveća kod pjetlića (4.020,80 g), zatim kopuna (3.704,10 g), dok su trupovi pilenki bili najlakši (3.127,90 g), međutim najveći randman je zabilježen kod pilenki. Završetkom tova, u dobi od 140 dana, kopuni su postigli prosječnu završnu masu od 5.218,30 grama. Uočene su promjene u boji jetre te je zabilježeno kako je meso kopuna svjetlije, žuće te manje crveno naspram mesa pjetlića. Istraživanjem nisu utvrđene razlike u senzorskom profilu, kao ni u svojstvima dopadljivosti između skupina.The aim of this study was to determine the slaughter characteristics and quality indicators of capon meat with reference to the caponization process and the fattening abilities achieved in groups that were reared in identical conditions. For the purposes of the research, 77 one-day-old chicks of the heavy hybrid line Sasso R9 were purchased. At the age of 28 days, the castration procedure was performed. After the procedure, the chicks were classified intp three groups: capons, cockerels and hens. Two slaughters were carried out, the first at the age of 90 days and the second at the age of 140 days. At the age of the 90 days the best fattening performance was observed in cockerels, except for feed conversion. After the first slaughter, the average carcass weight was the highest in cockerels (4.020,80 g), followed by capons (3.704,10 g), while hen carcasses were the lightest (3.127,90 g), however, the highest yield was recorded in hens. At the end of fattening, at the age of 140 days, the capons reached an average final weight of 5,218.30 grams. Changes in the color of liver were observed, and it was noted that the meat of capon is lightier, yellower and less red compared to the meat of the cockerels. The research did not establish any differences in the sensory profile, as well as in the likability traits between the groups
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