Generation of an UWB monocycle employing cross-phase modulation in a SOA-MZ interferometer

In the present article, an innovative approach for generation of an UWB monocycle is proposed and experimentally demonstrated. The proposed design features the combination of an interferometric device (SOA-Mach Zehnder interferometer) with an optical processor unit. The fusion of such components permits to generate, combine and customize UWB pulses. An optical pulse is used as pump signal and two optical carriers represent and the optical input of the system. The selection of a specific wavelength and therefore of a particular port provides the possibility of modifying the systems output pulse polarity. The capacity of transmitting several data sequence has been also evidenced.

A Knowledge-based Approach for Automatic Generation of Summaries of Behavior

Effective automatic summarization usually requires simulating human reasoning such as abstraction or relevance reasoning. In this paper we describe a solution for this type of reasoning in the particular case of surveillance of the behavior of a dynamic system using sensor data. The paper first presents the approach describing the required type of knowledge with a possible representation. This includes knowledge about the system structure, behavior, interpretation and saliency. Then, the paper shows the inference algorithm to produce a summarization tree based on the exploitation of the physical characteristics of the system. The paper illustrates how the method is used in the context of automatic generation of summaries of behavior in an application for basin surveillance in the presence of river floods.

Towards a new generation of solar cells: silicon supersaturated with titanium or vanadium

We have analyzed the spectral sub-bandgap photoresponse of silicon (Si) samples implanted with vanadium (V) and titanium (Ti) at different doses and subsequently processed by pulsed-laser melting.

Generador de exámenes de test aleatorio

En este documento se detalla, la planificación y elaboración de un paquete que respeta el estándar S4 de programación en lenguaje R. El paquete consiste en una serie de métodos y clases para la generación de exámenes tipos test y soluciones a partir de un archivo xls, que hace las funciones de una base de datos. El diseño propuesto está orientado a objetos y desarrolla un conjunto de clases que representan los contenidos de una prueba de evaluación tipo test: enunciados, peguntas y respuestas. Se ha realizado una implementación sencilla de un prototipo con las funciones básicas necesarias para generar los tests. Además se ha generado la documentación necesaria para crear el paquete, esto significa que cada método tiene una página de ayuda, que se podrá consultar desde un terminal con R, dicha documentación incluye ejemplos de ejecución de cada método.---ABSTRACT---In this document is detailed the elaboration and development of a package that meets the standard S4 of programming language R. This package consists of a group of methods and classes used for the generation of test exams and their solutions starting from a xls format file wich plays the role of a data base at the same time. These classes have been grouped in a way that the user could have a complete and easy vision of them. This division has been done by using data storage and functions whose tasks are more or less the same. Furthermore, the necessary documentation to create this package has also been generated, that means that every method has a help page wich can be called from a R terminal if necessary. This documentation has examples of the execution of every method.

Testing of Android testing tools: development of a benchmark for the evaluation

With the ever growing trend of smart phones and tablets, Android is becoming more and more popular everyday. With more than one billion active users i to date, Android is the leading technology in smart phone arena. In addition to that, Android also runs on Android TV, Android smart watches and cars. Therefore, in recent years, Android applications have become one of the major development sectors in software industry. As of mid 2013, the number of published applications on Google Play had exceeded one million and the cumulative number of downloads was more than 50 billionii. A 2013 survey also revealed that 71% of the mobile application developers work on developing Android applicationsiii. Considering this size of Android applications, it is quite evident that people rely on these applications on a daily basis for the completion of simple tasks like keeping track of weather to rather complex tasks like managing one’s bank accounts. Hence, like every other kind of code, Android code also needs to be verified in order to work properly and achieve a certain confidence level. Because of the gigantic size of the number of applications, it becomes really hard to manually test Android applications specially when it has to be verified for various versions of the OS and also, various device configurations such as different screen sizes and different hardware availability. Hence, recently there has been a lot of work on developing different testing methods for Android applications in Computer Science fraternity. The model of Android attracts researchers because of its open source nature. It makes the whole research model more streamlined when the code for both, application and the platform are readily available to analyze. And hence, there has been a great deal of research in testing and static analysis of Android applications. A great deal of this research has been focused on the input test generation for Android applications. Hence, there are a several testing tools available now, which focus on automatic generation of test cases for Android applications. These tools differ with one another on the basis of their strategies and heuristics used for this generation of test cases. But there is still very little work done on the comparison of these testing tools and the strategies they use. Recently, some research work has been carried outiv in this regard that compared the performance of various available tools with respect to their respective code coverage, fault detection, ability to work on multiple platforms and their ease of use. It was done, by running these tools on a total of 60 real world Android applications. The results of this research showed that although effective, these strategies being used by the tools, also face limitations and hence, have room for improvement. The purpose of this thesis is to extend this research into a more specific and attribute-­‐ oriented way. Attributes refer to the tasks that can be completed using the Android platform. It can be anything ranging from a basic system call for receiving an SMS to more complex tasks like sending the user to another application from the current one. The idea is to develop a benchmark for Android testing tools, which is based on the performance related to these attributes. This will allow the comparison of these tools with respect to these attributes. For example, if there is an application that plays some audio file, will the testing tool be able to generate a test input that will warrant the execution of this audio file? Using multiple applications using different attributes, it can be visualized that which testing tool is more useful for which kinds of attributes. In this thesis, it was decided that 9 attributes covering the basic nature of tasks, will be targeted for the assessment of three testing tools. Later this can be done for much more attributes to compare even more testing tools. The aim of this work is to show that this approach is effective and can be used on a much larger scale. One of the flagship features of this work, which also differentiates it with the previous work, is that the applications used, are all specially made for this research. The reason for doing that is to analyze just that specific attribute in isolation, which the application is focused on, and not allow the tool to get bottlenecked by something trivial, which is not the main attribute under testing. This means 9 applications, each focused on one specific attribute. The main contributions of this thesis are: A summary of the three existing testing tools and their respective techniques for automatic test input generation of Android Applications. • A detailed study of the usage of these testing tools using the 9 applications specially designed and developed for this study. • The analysis of the obtained results of the study carried out. And a comparison of the performance of the selected tools.

Mathematical modelling of neural processes within the oculomotor system

It is presented a mathematical model of the oculomotor plant, based on experimental data in cats. The system that generates, from the neuronal processes at the motoneuron, the control signals to the eye muscles that moves the eye. In contrast with previous models, that base the eye movement related motoneuron behavior on a first order linear differential equation, non-linear effects are described: A dependency on the eye angular position of the model parameters.

Microbes as engines of ecosystem function : When does community structure enhance predictions of ecosystem processes?

Peer reviewed

Generation of Functional Beta-Like Cells from Human Exocrine Pancreas

Funding: This work was supported by a grant from the Medical Research Council MR/J015277/1. The Scottish National Islet Transplant Programme is funded by the National Services Division of NHS Scotland. KRM was funded by a Fellowship from the Wellcome Trust / Scottish Translational Medicine and Therapeutics Initiative 85664. Acknowledgments This work was supported by a grant from the Medical Research Council MR/J015277/1. The Scottish National Islet Transplant Programme is funded by the National Services Division of NHS Scotland. KRM was funded by a Fellowship from the Wellcome Trust/ Scottish Translational Medicine and Therapeutics Initiative 85664. We thank Joanna Sweetman for assistance in optimisation of the immunogold staining.

Generation of CD8+ T cells specific for transporter associated with antigen processing deficient cells

Cells with impaired transporter associated with antigen processing (TAP) function express low levels of cell surface major histocompatibility complex (MHC) class I molecules, and are generally resistant to lysis by MHC class I restricted cytotoxic T lymphocytes (CTLs). Here we report the generation of MHC class I restricted CD8+ CTLs that surprisingly require target cell TAP deficiency for efficient recognition. C57BL/6 (B6) mice immunized with syngenic B7–1 (CD80) expressing TAP-deficient cells generated a potent CTL response against both TAP-deficient RMA-S tumor cells and TAP-deficient Con A blasts, whereas the corresponding TAP-expressing target cells were considerably less susceptible or resistant to lysis. The CTL epitopes recognized were expressed also by the human TAP-deficient cell line T2, transfected with appropriate MHC class I molecules. B6 mice immunized with B7–1-transfected TAP-deficient RMA-S cells were protected from outgrowth of a subsequent RMA-S tumor challenge. These findings are discussed in relation to the biochemical nature of MHC class I dependent CTL epitopes associated with impaired TAP function, as well as implications for immunotherapy and autoimmunity.

Generation of secretable and nonsecretable interleukin 15 isoforms through alternate usage of signal peptides

Two isoforms of human interleukin 15 (IL-15) exist. One isoform has a shorter putative signal peptide (21 amino acids) and its transcript shows a tissue distribution pattern that is distinct from that of the alternative IL-15 isoform with a 48-aa signal peptide. The 21-aa signal isoform is preferentially expressed in tissues such as testis and thymus. Experiments using different combinations of signal peptides and mature proteins (IL-2, IL-15, and green fluorescent protein) showed that the short signal peptide regulates the fate of the mature protein by controlling the intracellular trafficking to nonendoplasmic reticulum sites, whereas the long signal peptide both regulates the rate of protein translation and functions as a secretory signal peptide. As a consequence, the IL-15 associated with the short signal peptide is not secreted, but rather is stored intracellularly, appearing in the nucleus and cytoplasmic components. Such production of an intracellular lymphokine is not typical of other soluble interleukin systems, suggesting a biological function for IL-15 as an intracellular molecule.

The Development of Cell Processes Induced by tau Protein Requires Phosphorylation of Serine 262 and 356 in the Repeat Domain and Is Inhibited by Phosphorylation in the Proline-rich Domains

The differentiation of neurons and the outgrowth of neurites depends on microtubule-associated proteins such as tau protein. To study this process, we have used the model of Sf9 cells, which allows efficient transfection with microtubule-associated proteins (via baculovirus vectors) and observation of the resulting neurite-like extensions. We compared the phosphorylation of tau23 (the embryonic form of human tau) with mutants in which critical phosphorylation sites were deleted by mutating Ser or Thr residues into Ala. One can broadly distinguish two types of sites, the KXGS motifs in the repeats (which regulate the affinity of tau to microtubules) and the SP or TP motifs in the domains flanking the repeats (which contain epitopes for antibodies diagnostic of Alzheimer’s disease). Here we report that both types of sites can be phosphorylated by endogenous kinases of Sf9 cells, and that the phosphorylation pattern of the transfected tau is very similar to that of neurons, showing that Sf9 cells can be regarded as an approximate model for the neuronal balance between kinases and phosphatases. We show that mutations in the repeat domain and in the flanking domains have opposite effects. Mutations of KXGS motifs in the repeats (Ser262, 324, and 356) strongly inhibit the outgrowth of cell extensions induced by tau, even though this type of phosphorylation accounts for only a minor fraction of the total phosphate. This argues that the temporary detachment of tau from microtubules (by phosphorylation at KXGS motifs) is a necessary condition for establishing cell polarity at a critical point in space or time. Conversely, the phosphorylation at SP or TP motifs represents the majority of phosphate (>80%); mutations in these motifs cause an increase in cell extensions, indicating that this type of phosphorylation retards the differentiation of the cells.

Nitric oxide inhibits tumor necrosis factor-α-induced apoptosis by reducing the generation of ceramide

Apoptosis triggered by death receptors proceeds after defined signal-transduction pathways. Whether signaling at the receptor level is regulated by intracellular messengers is still unknown. We have investigated the role of two messengers, ceramide and nitric oxide (NO), on the apoptotic pathway activated in human monocytic U937 cells by tumor necrosis factor-α (TNF-α) working at its p55 receptor. Two transduction events, the receptor recruitment of the adapter protein, TRADD, and the activation of the initiator caspase, caspase 8, were investigated. When administered alone, neither of the messengers had any effect on these events. In combination with TNF-α, however, ceramide potentiated, whereas NO inhibited, TNF-α-induced TRADD recruitment and caspase 8 activity. The effect of NO, which was cGMP-dependent, was due to inhibition of the TNF-α-induced generation of ceramide. Our results identify a mechanism of regulation of a signal-transduction pathway activated by death receptors.

Generation of in vivo activating factors in the ischemic intestine by pancreatic enzymes

One of the early events in physiological shock is the generation of activators for leukocytes, endothelial cells, and other cells in the cardiovascular system. The mechanism by which these activators are produced has remained unresolved. We examine here the hypothesis that pancreatic digestive enzymes in the ischemic intestine may be involved in the generation of activators during intestinal ischemia. The lumen of the small intestine of rats was continuously perfused with saline containing a broadly acting pancreatic enzyme inhibitor (6-amidino-2-naphthyl p-guanidinobenzoate dimethanesulfate, 0.37 mM) before and during ischemia of the small intestine by splanchnic artery occlusion. This procedure inhibited activation of circulating leukocytes during occlusion and reperfusion. It also prevented the appearance of activators in portal venous and systemic artery plasma and attenuated initiating symptoms of multiple organ injury in shock. Intestinal tissue produces only low levels of activators in the absence of pancreatic enzymes, whereas in the presence of enzymes, activators are produced in a concentration- and time-dependent fashion. The results indicate that pancreatic digestive enzymes in the ischemic intestine serve as an important source for cell activation and inflammation, as well as multiple organ failure.

Generation of longer cDNA fragments from serial analysis of gene expression tags for gene identification

We have developed a technique called the generation of longer cDNA fragments from serial analysis of gene expression (SAGE) tags for gene identification (GLGI), to convert SAGE tags of 10 bases into their corresponding 3′ cDNA fragments covering hundred bases. A primer containing the 10-base SAGE tag is used as the sense primer, and a single base anchored oligo(dT) primer is used as an antisense primer in PCR, together with Pfu DNA polymerase. By using this approach, a cDNA fragment extending from the SAGE tag toward the 3′ end of the corresponding sequence can be generated. Application of the GLGI technique can solve two critical issues in applying the SAGE technique: one is that a longer fragment corresponding to a SAGE tag, which has no match in databases, can be generated for further studies; the other is that the specific fragment corresponding to a SAGE tag can be identified from multiple sequences that match the same SAGE tag. The development of the GLGI method provides several potential applications. First, it provides a strategy for even wider application of the SAGE technique for quantitative analysis of global gene expression. Second, a combined application of SAGE/GLGI can be used to complete the catalogue of the expressed genes in human and in other eukaryotic species. Third, it can be used to identify the 3′ cDNA sequence from any exon within a gene. It can also be used to confirm the reality of exons predicted by bioinformatic tools in genomic sequences. Fourth, a combined application of SAGE/GLGI can be applied to define the 3′ boundary of expressed genes in the genomic sequences in human and in other eukaryotic genomes.

Cleavage of the antithrombin III binding site in heparin by heparinases and its implication in the generation of low molecular weight heparin

Heparin has been used as a clinical anticoagulant for more than 50 years, making it one of the most effective pharmacological agents known. Much of heparin's activity can be traced to its ability to bind antithrombin III (AT-III). Low molecular weight heparin (LMWH), derived from heparin by its controlled breakdown, maintains much of the antithrombotic activity of heparin without many of the serious side effects. The clinical significance of LMWH has highlighted the need to understand and develop chemical or enzymatic means to generate it. The primary enzymatic tools used for the production of LMWH are the heparinases from Flavobacterium heparinum, specifically heparinases I and II. Using pentasaccharide and hexasaccharide model compounds, we show that heparinases I and II, but not heparinase III, cleave the AT-III binding site, leaving only a partially intact site. Furthermore, we show herein that glucosamine 3-O sulfation at the reducing end of a glycosidic linkage imparts resistance to heparinase I, II, and III cleavage. Finally, we examine the biological and pharmacological consequences of a heparin oligosaccharide that contains only a partial AT-III binding site. We show that such an oligosaccharide lacks some of the functional attributes of heparin- and heparan sulfate-like glycosaminoglycans containing an intact AT-III site.