Exact Feature Research Articles

Is a step in the primordial spectral index favoured by CMB data?

A sudden small change in the second derivative of the inflaton potentialcan result in a universal local feature in the spectrum of primordialperturbations generated during inflation. The exact solution describingthis feature \\cite{minu} is characterized by a step in the spectral indexmodulated by characteristic oscillations and results in a large running of thespectral index localized over a few e-folds of scale. In this paper weconfront this step-like feature with the 5 year WMAP results and demonstratethat it provides a better fit to this data than a featureless initial spectrum.If such a feature exists at all, then it should lie at sufficiently large scalesk0 ≲ 0.003 Mpc−1 corresponding to l ≲ 40. The signof the effect is shown to correspond to the negative running of nslocalized near this scale. This feature could arise as a result of a`mini-waterfall'-type fast second order phase transitionexperienced by an auxiliary heavy field during inflation, in a modelsimilar to hybrid inflation (though for a different choice of parameters).If this is the case, then theauxiliary field should be positively coupled to the inflaton.

Exact Feature Extraction Using Finite Rate of Innovation Principles With an Application to Image Super-Resolution

The accurate registration of multiview images is of central importance in many advanced image processing applications. Image super-resolution, for example, is a typical application where the quality of the super-resolved image is degrading as registration errors increase. Popular registration methods are often based on features extracted from the acquired images. The accuracy of the registration is in this case directly related to the number of extracted features and to the precision at which the features are located: images are best registered when many features are found with a good precision. However, in low-resolution images, only a few features can be extracted and often with a poor precision. By taking a sampling perspective, we propose in this paper new methods for extracting features in low-resolution images in order to develop efficient registration techniques. We consider, in particular, the sampling theory of signals with finite rate of innovation and show that some features of interest for registration can be retrieved perfectly in this framework, thus allowing an exact registration. We also demonstrate through simulations that the sampling model which enables the use of finite rate of innovation principles is well suited for modeling the acquisition of images by a camera. Simulations of image registration and image super-resolution of artificially sampled images are first presented, analyzed and compared to traditional techniques. We finally present favorable experimental results of super-resolution of real images acquired by a digital camera available on the market.

Searching for two feature singletons in the visual scene: the localized attentional interference effect

The localized attentional interference (LAI) effect was investigated in a visual search task requiring participants to simultaneously monitor two spatially separated features from the same or different dimensions. In Experiment 1, the search type was blocked and targets were defined by fixed feature values in two dimensions (e.g., a yellow item and a circular item). In contrast, in Experiment 2, participants had to look for a color and a form singleton, with the exact feature values varying randomly across trials. In both experiments, reaction times (RTs) were generally slower when two features were CLOSE to, rather than DISTANT from, each other. Moreover, RTs to CLOSE stimuli increased as the search set size increased, while RTs to DISTANT stimuli were unaffected by set size. Experiment 3 also used a singleton search task, but with the two singletons defined either in different dimensions or in the same dimension. A larger interference effect for CLOSE, as compared to DISTANT, stimuli was found for cross-dimension than for intra-dimension targets. These findings suggest that neighboring items, irrespective of whether these items are from the same or different dimensions, interfere with each other in attentional selection, and that searching for two cross-dimension targets may engage a process of dimension switching to effectively solve the ambiguity of each item, especially when these items are close to each other.

Identification and quantification of Nα-acetylated Y. pestis fusion protein F1-V expressed in Escherichia coli using LCMSE☆

N-terminal acetylation in E coli is a rare event catalyzed by three known N-acetyl-transferases (NATs), each having a specific ribosomal protein substrate. Multiple, gram-scale lots of recombinant F1-V, a fusion protein constructed from Y. Pestis antigens, were expressed and purified from a single stably transformed E. coli cell bank. A variant form of F1-V with mass increased by 42-43 Da was detected in all purified lots by electrospray orthogonal acceleration time-of-flight mass spectrometry (MS). Peptide mapping LCMS localized the increased mass to an N-terminal Lys-C peptide, residues 1-24, and defined it as +42.0308+/-0.0231 Da using a LockSpray exact mass feature and a leucine enkaphalin mass standard. Sequencing of the variant 1-24 peptide by LCMS and high-energy collision induced dissociation (LCMS(E)) further localized the modification to the amino terminal tri-peptide ADL and identified the modification as N(alpha)-acetylation. The average content of N(alpha)-acetylated F1-V in five lots was 24.7+/-2.6% indicating that a stable acetylation activity for F1-V was established in the E. coli expression system. Alignment of the F1-V N-terminal sequence with those of other known N(alpha)-acetylated ectopic proteins expressed in E. coli reveals a substrate motif analogous to the eukaryote NatA' acetylation pathway and distinct from endogenous E. coli NAT substrates.

Perpendicular Magnetic Recording Integration and Robust Design

We have investigated the effects of stray magnetic field upon a perpendicular magnetic recording (PMR) system, which consists of a single pole type head and a double-layered perpendicular medium. We found that fields in the plane of the disk could cause serious External magnetic flux concentrates around the edges of a return pole and can cause very large fields to appear in the medium. In addition, the writing operation significantly enhances this We called this kind of erasure corner erasure. Experimental 2.5-inch hard disk drives (HDDs) were used to study the combined effect of the external field and write field. We checked SER degradation after applying an in-plane field of 0.8 kA/m (10 Oe). With no write-current applied, there is no degradation. However, as little as 0.8 kA/m (10 Oe) applied during writing causes severe degradation equivalent to that produced by a 4.0 kA/m (50 Oe) field applied when the head is reading on-track. It is concluded that the realization of PMR in commercial HDD would require new transducer designs to solve these problems. We devised a new return pole design which has a stepped-back wing to improve the robustness against in-plane stray fields. The alternative design greatly reduces the concentration of magnetic flux at the edges of return pole. Consequently, the stepped wing structure achieves about twice the robustness of the conventional rectangular return pole. A method was developed to allow external field sensitivity to be carefully checked. The method allows the degraded areas of data to be associated with the exact feature on the head that caused the problem

A linear-time algorithm for Euclidean feature transform sets

The Euclidean distance transform of a binary image is the function that assigns to every pixel the Euclidean distance to the background. The Euclidean feature transform is the function that assigns to every pixel the set of background pixels with this distance. We present an algorithm to compute the exact Euclidean feature transform sets in linear time. The algorithm is applicable in arbitrary dimensions.

Geometry design model of a precise form-milling cutter based on the machining characteristics

This paper presents a new approach to design a form milling cutter for precisely obtaining the complex free-form surfaces. In this study, the intersection point of the rake surface, helix flute and clearance flank is appropriately defined due to its significant role in the design and grinding performance. The angle-solid-block analysis is developed to establish the new cutter geometry model. Hence, a new form-milling cutter satisfying the requirements of machining characteristics of workpiece can be designed. In addition, the cutter geometric model can be adopted to map out the measuring strategy with minimum measured points to attain the exact geometric feature of cutter.

Vegetation's Red Edge: A Possible Spectroscopic Biosignature of Extraterrestrial Plants

Earth's deciduous plants have a sharp order-of-magnitude increase in leaf reflectance between approximately 700 and 750 nm wavelength. This strong reflectance of Earth's vegetation suggests that surface biosignatures with sharp spectral features might be detectable in the spectrum of scattered light from a spatially unresolved extrasolar terrestrial planet. We assess the potential of Earth's step-function-like spectroscopic feature, referred to as the "red edge," as a tool for astrobiology. We review the basic characteristics and physical origin of the red edge and summarize its use in astronomy: early spectroscopic efforts to search for vegetation on Mars and recent reports of detection of the red edge in the spectrum of Earthshine (i.e., the spatially integrated scattered light spectrum of Earth). We present Earthshine observations from Apache Point Observatory (New Mexico) to emphasize that time variability is key to detecting weak surface biosignatures such as the vegetation red edge. We briefly discuss the evolutionary advantages of vegetation's red edge reflectance, and speculate that while extraterrestrial "light-harvesting organisms" have no compelling reason to display the exact same red edge feature as terrestrial vegetation, they might have similar spectroscopic features at different wavelengths than terrestrial vegetation. This implies that future terrestrial-planet-characterizing space missions should obtain data that allow time-varying, sharp spectral features at unknown wavelengths to be identified. We caution that some mineral reflectance edges are similar in slope and strength to vegetation's red edge (albeit at different wavelengths); if an extrasolar planet reflectance edge is detected care must be taken with its interpretation.

Ion-exchange funneling in thin-film coating modification of heterogeneous electrodialysis membranes

Inexpensive highly permselective heterogeneous ion-exchange membranes are prohibitively highly polarizable by a dc current for being used in electrodialysis. According to recent experiments, polarizability of these membranes may be considerably reduced by casting on their surface a thin layer of crosslinked polyelectrolyte, slightly charged with the same sign as the membrane's charge. The present paper is concerned with this effect. Concentration polarization of a permselective heterogeneous ion-exchange membrane by a dc current is determined by geometric factors, such as, the typical size of the ion-permeable "gates" at the membrane surface relative to the separation distance between them and the diffusion layer thickness. The main quantitative characteristic of polarizability of a heterogeneous membrane is its voltage/current curve with its typical saturation at the limiting current, which is lower than that for a homogeneous membrane. In the present study we modify the previously developed two-dimensional model of ionic transport in a diffusion layer at a heterogeneous ion-exchange membrane by including into consideration a homogeneous ion-exchange layer adjacent to the membrane surface. A numerical solution of the respective boundary value problem shows that, indeed, adding even a very thin and weakly charged layer of this kind increases the value of the limiting current, to that of a homogeneous membrane. What differs, for different values of coating parameters, is the form of the voltage/current curves but not the value of the limiting current, namely: the thinner is the coating and the lower the fixed charge density in it, the "slower" is the approach of the limiting current. In order to explain this feature, a simple limiting model of modified membrane is derived from the original two-layer model. In this limiting model, asymptotically valid for a thin coating, solution of the ionic transport equations in it is replaced, via a suitable averaging procedure, by a single nonlinear boundary condition for the membrane/solution interface. Rigorous analysis shows that the aforementioned property of the limiting current is an exact mathematical feature of this limiting model, when the underlying physical phenomenon is the funneling of counterions by the charged layer from the impermeable parts of the membrane towards the "entrance gates." An approximate analytical solution, developed for this model, compares well with the exact numerical one.

The Significance of the MQC Experiment

It is generally agreed that quantum mechanics (QM) describes brilliantly the behavior of matter at the atomic and subatomic level. However, many people, including the author, believe that if it is taken seriously at the level of everyday life, it leads to insuperable difficulties, exemplified by the fate of Schrodinger's unfortunate cat. If, therefore, one is prepared to envisage seriously the possibility that if QM is pushed sufficiently far it may break down or have to be supplemented by some new and currently unforeseeable principle, then the obvious axis along which to try to “push” it is that which brings us closest to the world of everyday life. Thus, we are motivated to try to define which exact feature most sharply distinguishes those applications of QM at the everyday level that appear paradoxical: to seek, in fact, a quantitative measure of the degree of “Schrodinger's-cattiness” of various physical situations. Although this is no doubt a subjective question, I explore two plausible candidates: one involving the divergence, in the two branches of the (notional) quantum superposition, of some “macroscopic” physical quantity; the other invoking the idea of “disconnectivity”a notion that has much in common with the concept of “degree of entanglement” currently employed in the context of EPR-Bell-type experiments. Having tried to isolate and define the “axis” along which we are trying to push QM, I then discuss the main generic obstacles to this program, which may be summarized as (1) quasi-classicality, (2) decoherence, and (3) Franck-Condon suppression. Finally, I emphasize the importance not only of verifying (or not) that QM continues to predict correctly the experimental behavior as we progress along the relevant axis, but of confronting its predictions with those of a class of alternative, “macrorealistic” theories. I comment on the implications of various possible outcomes to this confrontation.

Molecular Motion and Properties of Flexible Fluoropolymers by 1H Pulse NMR

1H pulse NMR experiments are carried out for graft fluoropolymers with both flexibility and thermoplasticity over a wide range of temperatures, in order to elucidate exact dynamical feature in the solid state. From these experimental results, it was found that the graft fluoropolymers consist of a rubber-like (mobile) component and a crystalline (immobile) component in the solid state, and the graft fluoropolymer with different molecular weight of the base polymer being the rubber-like component has almost same 1H T2 Value. These molecular motions clearly associate with mechanical properties.

芳香族ポリケトンの合成に関する最近の展開

Aromatic polyketone is one of the most highly performed super engineering plastics With the progress of clarification of the exact feature of structure and thermal behavior of the polymers, a lot of novel aromatic polyketones have appeared and various synthetic approaches were undertaken in these years The recent advances of polyketones are reviewed from synthetic interests. (1) New synthetic reactions, introduction and removal of tentative auxiliary groups in order to maintain the flexibility of polymer chain during chain elongation reaction, and uses of transition metals as a highly effective catalyst were developed for achievement of high-molecular-weight polymer skeleton. (2) Fundamental structural perturbation was undertaken by introduction of crankshaft rings and additional conjugated moieties. (3) Introduction of side groups and their chemical transformation were undertaken to perform new structures and advanced properties. (4) Fine syntheses and reactions of designed oligomers and polymer precursors both for model studies and reactive oligo/polyketones were also investigated. The reports in 1992 and later were mainly surveyed.

Achieving jitter-free and predictable real-time control by accurately timed computer peripherals

Abstract Contemporary real-time computers are unable to manipulate external parallel processes simultaneously, and their response times are generally unpredictable, resulting in jitter of the corresponding sampled data systems. It is shown that these problems can be easily solved by endowing process control computers with input/output facilities, working fully in parallel, and making use of exact time specifications. The required system functions are compiled, the design of the additional hardware components is given, and the real-time operating system support is discussed. As a by-product, the exact timing feature of input/output operations opens a new way of synchronising the access of multiple tasks to shared peripherals, which is based on the dimension time.

Exact integrability of strings in D-dimensional de Sitter spacetime.

We show the complete integrability of the string propagation in $D$-dimensional de Sitter spacetime. We find that the string equations of motion, which correspond to a noncompact $\mathrm{O}(D, 1)$-symmetric $\ensuremath{\sigma}$ model, plus the string constraints, are equivalent to a generalized sinh-Gordon equation. In $D=2$ this is the Liouville equation, in $D=3$ this is the standard sinh-Gordon equation, and in $D=4$ this equation is related to the ${B}_{2}$ Toda model. We show that the presence of instability is a general exact feature of strings in de Sitter space, as a direct consequence of the strong instability of the generalized sinh-Gordon Hamiltonian (which is unbounded from below), irrespective of any approximative scheme. We exhibit B\"acklund transformations for this generalized sinh-Gordon equation, which relate expanding and shrinking string solutions. We find all classical solutions in $D=2$ and physically analyze them. In $D=3$ and $D=4$, we find the asymptotic behaviors of the solutions in the instability regime. The exact solutions exhibit asymptotically all the characteristic features of string instability: namely, the logarithmic dependence of the cosmic time $u$ on the world sheet time $\ensuremath{\tau}$ for $u\ensuremath{\rightarrow}\ifmmode\pm\else\textpm\fi{}\ensuremath{\infty}$, the stretching (or the shrinking) of the proper string size, and the proportionality between $\ensuremath{\tau}$ and the conformal time.

A precisely timed fully parallel process input/output facility for control applications

Contemporary real-time computers are unable to manipulate external parallel processes simultaneously, and their response times are generally unpredictable. It is shown that these problems can be solved by endowing process control computers with input/output facilities, working fully in parallel, and making use of exact time specifications. The required system functions are compiled, the design of the additional hardware components is given, and the supporting elements needed in high-level languages and real-time operating systems are discussed. As a by-product, the exact timing feature of input/output operations opens a new way of synchronising the access of multiple tasks to shared peripherals, which is based on the parameter time.