Russian Doll Renormalization Group and Superconductivity

We show that an extension of the standard BCS Hamiltonian leads to an infinite number of condensates with different energy gaps and self-similar properties, described by a cyclic RG flow of the BCS coupling constant which returns to its original value after a finite RG time.Comment: 4 pages, 2 figs, RevTex

Computing vs. Genetics

This chapter first presents the interrelations between computing and genetics, which both are based on information and, particularly, self-reproducing artificial systems. It goes on to examine genetic code from a computational viewpoint. This raises a number of important questions about genetic code. These questions are stated in the form of an as yet unpublished working hypothesis. This hypothesis suggests that many genetic alterations are caused by the last base of certain codons. If this conclusive hypothesis were to be confirmed through experiementation if would be a significant advance for treating many genetic diseases

Novel Method to Improve the Signal to Noise Ratio in the Far-field Results Obtained from Planar Near Field Measurements.

A method to reduce the noise power in far-field pattern without modifying the desired signal is proposed. Therefore, an important signal-to-noise ratio improvement may be achieved. The method is used when the antenna measurement is performed in planar nearfield, where the recorded data are assumed to be corrupted with white Gaussian and space-stationary noise, because of the receiver additive noise. Back-propagating the measured field from the scan plane to the antenna under test (AUT) plane, the noise remains white Gaussian and space-stationary, whereas the desired field is theoretically concentrated in the aperture antenna. Thanks to this fact, a spatial filtering may be applied, cancelling the field which is located out of the AUT dimensions and which is only composed by noise. Next, a planar field to far-field transformation is carried out, achieving a great improvement compared to the pattern obtained directly from the measurement. To verify the effectiveness of the method, two examples will be presented using both simulated and measured near-field data

Tangential projections and secant defective varieties

Going one step further in Zak's classification of Scorza varieties with secant defect equal to one, we characterize the Veronese embedding of $\P^n$ given by the complete linear system of quadrics and its smooth projections from a point as the only smooth irreducible complex and non-degenerate projective subvarieties of $\P^N$ that can be projected isomorphically into $\P^{2n}$ when $N\geq\binom{n+2}{2}-2$.Comment: To appear in Bulletin of the London Mathematical Societ

Application of sources reconstruction techniques: Theory and practical results.

In this paper, four new applications of sources reconstruction techniques (also called diagnostic techniques) are presented. First of all, the important information of such techniques will be mentioned, seeing that they are a tool to obtain the extremely near field from the measured data. Depending on the region where these data are taken (near field or far field), the reconstruction method will be different. Also, all of them may be classified in other two groups depending on its features: Integral Equation Methods (IEM) or Modal Expansion Methods. Classical applications of such techniques are errors detection, like phase errors in arrays or conformai errors in reflectors, therefore, they constitute an important antenna design tool. But also and it has been said, they can be used as the basis to other applications whose aim is to improve the measurement results in anechoic chambers or non anechoic environments. Here, four of them are presented, being the reflection cancelling, the detection of unwanted radiation points, the truncation error reduction in planar or cylindrical near-field and the noise reduction

Comparison of Anterior Denture Teeth Arrangements Made with the Tooth Mold Template and Definitive Computer-Aided Design & Computer-Aided Manufacturing Complete Removable Dental Prostheses

Introduction: There is a dearth of information in the refereed literature regarding esthetics of CAD/CAM complete removable dental prostheses (CRDPs). The purpose of this study was to investigate and compare the anterior denture teeth arrangement made with the medium-size anterior tooth mold template to CAD/CAM complete removable dental prostheses fabricated with bonded denture teeth and milled teeth. Material and methods: Poly-vinyl siloxane impression were made of an edentulous maxillary model and selected for use as the patient template. The edentulous model was mounted on a semi-adjustable articulator. Definitive impressions and jaw relation records were made according to the manufacturer’s protocol. Digital mock-ups of the denture tooth arrangement were received by the manufacturer and confirmed prior to processing. Ten CRDPs were generated; subgroups of 5 units were made and divided into 2 groups. One-half of the CRDPs were made by bonding manufactured denture teeth onto denture base milled from pre-polymerized PMMA pucks, while the other half were made by milling denture teeth directly. For comparison, a Canon 70D camera mounted on a tripod was used for photographic documentation. All photos were taken during the same day. Reference markers placed on the edentulous model were used to orient and measure photos using Photoshop CS4. Data was collected in the X-plane and the Y-plane and compared with the tooth mold template. Data were statistically analyzed by Mann-Whitney U and Wilcoxon signed-rank tests (α=.05) Results: No statistical difference was found when CAD/CAM CRDPs milled and bonded were compared. The tooth mold template represented the position of the central incisors on the milled teeth and bonded teeth CRDPs. The inter-canine distance was found to be 5 mm narrower on the CRDPs than the tooth mold template. The canines on the CRDPs were 1 to 2 mm incisal when compared to the tooth mold template. Conclusions: Tooth arrangements in bonded and milled CAD/CAM CRDPs did not accurately reproduce the tooth mold template’s measurements in terms of intercanine distance and position. There was no significant difference between tooth position on the milled and bonded CAD/CAM CRDPs

Efficient and Accurate hybrid GO-Spectral Algorithm to Design Conformal Serrated-Edge Reflectors Operating as Collimators in Millimeter Wave Compact Ranges

This paper presents a hybrid analysis algorithm, which is used at Radiation Group (UPM) to carry out the design of a conformal serrated-edge reflector for the mm-Wave compact range UPM facility. Main features of this algorithm involve its capability of handling conformal serrated rim parabolic reflectors, accuracy and computational efficiency

Antenna Measurement System at 300 GHz for the Terasense Project

The aim of this paper is to introduce the design techniques used to develop the antenna measurement system for the Terasense Project. This project, funded by the Spanish Government, involves millimetre-wave systems design. One of these systems is an antenna measurement facility. The antenna measurement system operates in a banded range of frequency. The lower frequencies deal between 75–110 GHz (WR10 operation range) and the upper frequencies are set between 220–325 GHz (WR03). Among the different possible configurations, the reflector-based compact range is chosen. The quiet zone is generated by a serrated-edge reflector, fed by a low gain horn. In this paper we will focus on the reflector design. A serrations study is carried out and quiet zone acquisition results are obtained

New methods to reduce leakage errors in planar near-field measurements

This paper describes two methods to cancel the effect of two kinds of leakage signals which may be presented when an antenna is measured in a planar near-field range. One method tries to reduce leakage bias errors from the receiver¿s quadrature detector and it is based on estimating the bias constant added to every near-field data sample. Then, that constant is subtracted from the data, removing its undesired effect on the far-field pattern. The estimation is performed by back-propagating the field from the scan plane to the antenna under test plane (AUT) and averaging all the data located outside the AUT aperture. The second method is able to cancel the effect of the leakage from faulty transmission lines, connectors or rotary joints. The basis of this method is also a reconstruction process to determine the field distribution on the AUT plane. Once this distribution is known, a spatial filtering is applied to cancel the contribution due to those faulty elements. After that, a near-field-to-far-field transformation is applied, obtaining a new radiation pattern where the leakage effects have disappeared. To verify the effectiveness of both methods, several examples are presented