3,117,656 research outputs found

    Absolutely continuous spectrum for the isotropic Maxwell operator with coefficients that are periodic in some directions and decay in others

    Full text link
    The purpose of this paper is to prove that the spectrum of an isotropic Maxwell operator with electric permittivity and magnetic permeability that are periodic along certain directions and tending to a constant super-exponentially fast in the remaining directions is purely absolutely continuous. The basic technical tools is a new ``operatorial'' identity relating the Maxwell operator to a vector-valued Schrodinger operator. The analysis of the spectrum of that operator is then handled using ideas developed by the same authors in a previous paper

    HUNGER AND WAITING IN THIRD WORLD LITERATURE

    Get PDF
    Using colonial discourse and post-colonial theory as a point of reference, this article takes a look at colonialism as experienced in the so-called third world and see how the experience has helped shaped the literary production of the countries and people so colonized. The study examines the British idea of 'Empire' and the colonial enterprise in a selected range of 20th-century texts, in an attempt to understand how imperialism affected literary texts produced in some former colonies particularly those in Africa, the Caribbean and Latin America. Texts to be considered in this study include: Marquez’s No One Writes to the Colonel, Enroll John’s Moon on a Rainbow Shawl and Marechera’s House of Hunger. The study will be viewing a literature characterized by elements of the fantastic woven into the story. A literature that scrutinizes society to its basis by examining the postcolonial hangover, a literary trend that separates the literature of the “subject” from the literature of the “other

    Interactive form creation: exploring the creation and manipulation of free form through the use of interactive multiple input interface

    Get PDF
    Most current CAD systems support only the two most common input devices: a mouse and a keyboard that impose a limit to the degree of interaction that a user can have with the system. However, it is not uncommon for users to work together on the same computer during a collaborative task. Beside that, people tend to use both hands to manipulate 3D objects; one hand is used to orient the object while the other hand is used to perform some operation on the object. The same things could be applied to computer modelling in the conceptual phase of the design process. A designer can rotate and position an object with one hand, and manipulate the shape [deform it] with the other hand. Accordingly, the 3D object can be easily and intuitively changed through interactive manipulation of both hands.The research investigates the manipulation and creation of free form geometries through the use of interactive interfaces with multiple input devices. First the creation of the 3D model will be discussed; several different types of models will be illustrated. Furthermore, different tools that allow the user to control the 3D model interactively will be presented. Three experiments were conducted using different interactive interfaces; two bi-manual techniques were compared with the conventional one-handed approach. Finally it will be demonstrated that the use of new and multiple input devices can offer many opportunities for form creation. The problem is that few, if any, systems make it easy for the user or the programmer to use new input devices

    Accelerating and abruptly-autofocusing beam waves in the Fresnel zone of antenna arrays

    Get PDF
    We introduce the concept of spatially accelerating (curved) beam waves in the Fresnel region of properly designed antenna arrays. These are transversely localized EM waves that propagate in free space in a diffraction-resisting manner, while at the same time laterally shifting their amplitude pattern along a curved trajectory. The proposed beams are the radiowave analogue of Airy and related accelerating optical waves, which, in contrast to their optical counterparts, are produced by the interference of discrete radiating elements rather than by the evolution of a continuous wavefront. Two dyadic array configurations are proposed comprising 2D line antennas: linear phased arrays with a power-law phase variation and curved power-law arrays with in-phase radiating elements. Through analysis and numerical simulations, the formation of broadside accelerating beams with power-law trajectories is studied versus the array parameters. Furthermore, the abrupt autofocusing effect, that occurs when beams of this kind interfere with opposite acceleration, is investigated. The concept and the related antenna setups can be of use in radar and wireless communications applications

    Ventilator-Associated Pneumonia and PaO2/FIO2 Diagnostic Accuracy: Changing the Paradigm?

    Get PDF
    BACKGROUND: Ventilator-associated pneumonia (VAP) is associated to longer stay and poor outcomes. Lacking definitive diagnostic criteria, worsening gas exchange assessed by PaO2/FIO2 ≀ 240 in mmHg has been proposed as one of the diagnostic criteria for VAP. We aim to assess the adequacy of PaO2/FIO2 ≀ 240 to diagnose VAP. METHODS: Prospective observational study in 255 consecutive patients with suspected VAP, clustered according to PaO2/FIO2 ≀ 240 vs. > 240 at pneumonia onset. The primary analysis was the association between PaO2/FIO2 ≀ 240 and quantitative microbiologic confirmation of pneumonia, the most reliable diagnostic gold-standard. RESULTS: Mean PaO2/FIO2 at VAP onset was 195 ± 82; 171 (67%) cases had PaO2/FIO2 ≀ 240. Patients with PaO2/FIO2 ≀ 240 had a lower APACHE-II score at ICU admission; however, at pneumonia onset they had higher CPIS, SOFA score, acute respiratory distress syndrome criteria and incidence of shock, and less microbiological confirmation of pneumonia (117, 69% vs. 71, 85%, p = 0.008), compared to patients with PaO2/FIO2 > 240. In multivariate logistic regression, PaO2/FIO2 ≀ 240 was independently associated with less microbiological confirmation (adjusted odds-ratio 0.37, 95% confidence interval 0.15-0.89, p = 0.027). The association between PaO2/FIO2 and microbiological confirmation of VAP was poor, with an area under the ROC curve 0.645. Initial non-response to treatment and length of stay were similar between both groups, while hospital mortality was higher in patients with PaO2/FIO2 ≀ 240. CONCLUSION: Adding PaO2/FIO2 ratio ≀ 240 to the clinical and radiographic criteria does not help in the diagnosis of VAP. PaO2/FIO2 ratio > 240 does not exclude this infection. Using this threshold may underestimate the incidence of VAP.info:eu-repo/semantics/publishedVersio

    Adipokinetic hormone enhances nodule formation and phenoloxidase activation in adult locusts injected with bacterial lipopolysaccharide

    Get PDF
    Interactions between the locust endocrine and immune systems have been studied in vivo in relation to nodule formation and activation of the prophenoloxidase cascade in the haemolymph. Injection of bacterial lipopolysaccharide (LPS) extracted from Escherichia coli induces nodule formation in larval and adult locusts but does not increase phenoloxidase activity in the haemolymph. Nodule formation starts rapidly after injection of LPS and is virtually complete within 8 h, nodules occurring mainly associated with the dorsal diaphragm on either side of the heart, but sometimes with smaller numbers associated with the ventral diaphragm on either side of the nerve cord. Co-injection of adipokinetic hormone-I (Lom-AKH-I) with LPS stimulates greater numbers of nodules to be formed in larval and adult locusts, and activates phenoloxidase in the haemolymph of mature adults but not of nymphs. The effect of co-injection of Lom-AKH-I with LPS on nodule formation is seen at low doses of hormone; only 0.4 pmol of Lom-AKH-I per adult locust is needed to produce a 50% increase in the number of nodules formed. When different components of LPS from the E. coli Rd mutant are tested, the mono- and the diphosphoryl Lipid A components have similar effects to the intact LPS. Remarkably, detoxified LPS activates phenoloxidase in the absence of Lom-AKH-I, although co-injection with hormone does enhance this response. Both diphosphoryl Lipid A and detoxified LPS induce a level of nodule formation that is enhanced by co-injection of Lom-AKH-I, but monophosphoryl Lipid A does not initiate nodule formation even when injected with hormone. Co-injection of a water-soluble inhibitor of eicosanoid synthesis, diclofenac (2-[(2, 6-dichlorophenyl)amino] benzeneacetic acid), reduces nodule formation in response to injections of LPS (both in the absence and presence of hormone) in a dose-dependent manner, but does not prevent activation of phenoloxidase in adult locusts. It is shown that nodule formation and activation of the prophenoloxidase in locust haemolymph can both be enhanced by Lom-AKH–I, but it is argued that these processes involve distinct mechanisms in which eicosanoid synthesis is important for nodule formation, but not for the increased phenoloxidase activity

    PSYCHOLOGICAL CONFLICTS OF THE MAIN CHARACTERS ON “DECEPTIONS” NOVEL BY JUDITH MICHAEL

    Get PDF
    In literary works, especially novel, we find various kinds of problems, which take place in the daily life of human beings. Novel is a story in prose, long enough to fill one or more volumes about imaginary or historical people. Therefore a novel includes psychological conflicts as its component. In facts, that the students can learn much from literary works, especially novel which gives them a picture of life. The purpose of this study was to answer the research problems, that is to find out: the psychological conflicts faced by the main characters, the most dominant conflict that faced by the main characters, and the way of the main characters solve their problems. The method that is used in this study was descriptive method because there is no administration or control of treatment. It followed the procedures of the objective approach in which the writer applied the literary research, after that she selected the supporting data, such as books, and literary theories. The result of this study shows that the types of psychological conflicts that the main characters faced are Avoidance-Avoidance Conflicts and Approach-Avoidance Conflicts. The most dominant psychological conflicts faced the main characters are the former because they exist more frequently than the later in this story. And the solution of Avoidance-Avoidance Conflicts shows that Sabrina finally determines to receives Stephanie’s desire, Sabrina finally decides to stay in Stephanie’s house, Sabrina finally decides to tells the truth to other people that actually she is not Stephanie but Sabrina. And the solution of Approach-Avoidance Conflicts shows that Garth finally decides to receive Sabrina as his wife and also forgives her

    BBGKY hierarchy in scalar QFT

    Get PDF
    This work is dedicated to obtaining of analog of Bogoliubov's chain for the case of complex scalar field in QFT and renormalization problem of obtained equations is discussed
    • 

    corecore