Compact charge and capacitance modeling of undoped ultra-thin body (UTB) SOI MOSFETs

We present an analytic, explicit and continuous charge model for a long-channel UTB (ultra-thin body) SOI (silicon-on-insulator) MOSFET, from which analytical expressions of the total capacitances are obtained. Our model is valid from below to well above threshold, without suffering from discontinuities between the regimes. It is based on a unified charge control model derived from Poisson’s equation. The drain-current, charge and capacitances expressions result in continuous explicit functions of the applied bias.The calculated capacitance characteristics are validated by 2D numerical simulations showing a very good agreement for different silicon film thicknesses.     

Explicit model for the gate tunneling current in double-gate MOSFETs

In this paper, we present an explicit compact quantum model for the gate tunneling current in double-gate metal–oxide–semiconductor field-effect transistors (DG-MOSFETs). Specifically, an explicit closed-form expression is proposed, useful for the fast evaluation of the gate leakage in the context of electrical circuit simulators. A benchmarking test against 1D self-consistent numerical solution of Schrödinger–Poisson (SP) equations has been performed to demonstrate the accuracy of the model.     

Use of β-hydroxyacyl-CoA-dehydrogenase (HADH) activity to differentiate frozen from unfrozen fish and shellfish

 Further work on an enzymic method to differentiate frozen from unfrozen fish and shellfish is reported. The method is based on the release of the β-hydroxyacyl-CoA-dehydrogenase (HADH) from mitochondria during freezing. Enzymic activity was evaluated in fresh and frozen thawed samples from sole (Solea solea), sea bream (Pagellus centrodontus), hake (Merluccius merluccius), gilt headed bream (Sparus aurata), sea bass (Dicentrarchus labrax), salmon (Salmo salar), prawn (Penaeus japonicus) and Norwegian lobster (Nephrops norvegicus). Changes in the HADH activity of fresh and frozen thawed samples were compared after freezing at –196  °C for 15 min. Two values were obtained: U (by dividing: HADH activity of samples frozen at –196  °C, then thawed/HADH activity of unfrozen samples) and F (by dividing: HADH activity of samples frozen at –18  °C, thawed, then frozen at –196  °C /HADH activity of samples frozen at –18  °C, then thawed). Statistical analysis showed significant differences (P≤0.05) between both quotients for gilt headed bream, salmon, sea bream, sole and prawn, and an arbitrary limit was set at 2 to differentiate frozen thawed from unfrozen samples. The application of this limit made it possible to discriminate the unfrozen from the frozen thawed state of around 90% of the total samples analysed. Best results were obtained for prawn (100% of samples differentiated). In the present paper, a laboratory routine is proposed based on the comparison of the HADH activity of a sample analysed straight away and that of a sample frozen at –196  °C and then thawed. The reported method is simple and fast. The entire laboratory procedure can be performed in 45 min. Received: 20 July 1998 / Revised version: 2 November 1998     

Browning susceptibility of minimally processed Baby and Romaine lettuces

 This study was conducted to determine the effects of cultivar, tissue susceptibility and storage temperature on the keeping quality of minimally processed Baby and Romaine lettuces. Midrib and photosynthetic tissues were lightly processed and stored for up to 7 days at 5  °C and 13  °C. Changes in L ^* and a ^* values and absorbance at 430 nm were compared. The relationship between polyphenols, phenylalanine ammonia lyase (PAL) and polyphenol oxidase (PPO) activities and browning was examined. Measurements of L ^* and a ^* values on midribs showed that browning discoloration was the same for Baby as for Romaine lettuces and there was no relationship for temperature. In addition, L ^* and a ^* values in photosynthetic tissue indicated a decrease in green pigmentation during storage, especially at 13  °C. For both kinds of tissue at the end of cold storage an increase in soluble brown polymers was detected. In midribs, total phenolics increased significantly throughout the storage period because of the tissue-wounding response. The photosynthetic tissue had a higher phenolic content than the midrib one. For both kinds of tissue an increase in PPO activity occurred throughout cold storage. On the other hand, PAL activity in midrib tissue only increased initially, followed by a slow decline to reach normal levels. Browning potential estimated by L ^* values correlated significantly (P>95%) with PPO activity and with absorbance at 430 nm for Romaine lettuce. Based on colour and browning potential no differences between Romaine and Baby lettuce cultivars were observed. However, photosynthetic tissue was the most suitable tissue for the preparation of minimally processed salad mixes because of its high phenolic content. Received: 28 September 1998     

Disruption and phenotypic analysis of seven ORFs from the left arm of chromosome XV of Saccharomyces cerevisiae

We have disrupted seven open reading frames (ORFs) located in the left arm of chromosome XV of the yeast Saccharomyces cerevisiae. These ORFs, previously discovered by our laboratory during the programme of systematic sequencing of the yeast genome, are YOL152w, YOL151w, YOL149w, YOL130w, YOL128c, YOL125w and YOL124c. In most cases, the short flanking homology (SFH) replacement technique has been used. The mutants were analysed for different phenotypic tests. Disruption of YOL130w (also known as ALR1) produced a lethal phenotype, despite the presence of a highly similar gene in the yeast genome (ALR2/YFL050C). Disruption of YOL149w (also known as DCP1, and encoding an mRNA decapping enzyme) results in lethality in the FY1679 background, although it allows slow growth in the CEN.PK141 background. Disruption of the remaining ORFs did not result in readily detectable phenotypic changes.     

Disruption and basic phenotypic analysis of six novel genes from the left arm of chromosome XIV of Saccharomyces cerevisiae

We describe here the construction of six deletion mutants and their basic phenotypic analysis in three different backgrounds. The six genes were disrupted in three diploid strains (FY1679, W303 and CEN.PK2) by the long flanking homology (LFH) method (Wach, 1996). Transformants were selected as geneticin (G418)-resistant colonies and correct integration of the kanMX4 cassette was checked by colony PCR. Following sporulation of the heterozygous diploids, tetrads were dissected and scored for segregation of G418-resistance and auxotrophic markers. One of the six ORFs (YNL158w) corresponds to an essential gene which has no homology with other genes present in the databases and has two predicted transmembrane domains. Growth tests performed on different media at 15 degrees C, 30 degrees C or 37 degrees C with haploid deletants of the five non-essential genes revealed no apparent phenotype in any of them.     

Terahertz-Induced Magnetoresistance Oscillations in High-Mobility 2D Electron Systems Under Bichromatic and Multichromatic Excitation

In this work, we investigated the magnetotransport under terahertz radiation in high-mobility two-dimensional electron systems, focusing on irradiation by bichromatic and multichromatic terahertz sources. We observed strong modulation of the Shubnikov-de Haas oscillations at sufficient terahertz radiation power. We determined that the origin of the modulation was the interference between the average distance advanced by the scattered electrons between irradiated Landau states and the available initial density of states at a certain magnetic field. In the case of multifrequency illumination, we found that with the appropriate frequencies, the irradiated magnetoresistance could reach an almost zero-resistance state regime even at moderate radiation power.     

Robust Stability of Multivariate Polynomials. Part 1: Small Coefficient Perturbations

This paper presents a detailed analysis of some classes of stable multivariate polynomials. The main aim of the analysis is to give conditions under which polynomials preserve stability when they are subjected to small coefficient variations. The maximal class of such polynomials is introduced. Some basic properties of polynomials from this class are obtained.     

Teamwork assessment in the educational web of data: A learning analytics approach towards ISO 10018

The Web of Data is an emerging research field that contributes to make better decisions because it gathers, combines and analyses different data sources available worldwide. Educational data is an interesting domain because it deals with the quality of the education itself and educational institutions which are common goals for every country. This paper is devoted to present how this idea has been used to improve a learning analytics tool. By means of this tool, teachers can perform teamwork competence assessment of a group of students taking into account how the individuals acquire the essential components of such competence. In this sense, authors use the Comprehensive Training Model of the Teamwork Competence in Engineering Domain (CTMTC) method to gather competence evidences and improve the system with a learning analytics tool to support the process. This tool is able to transform competence evidences and stores them in a competence ontology built upon ISO 10018 concepts. The final result is the production of educational results for the web of data.