Semiconductor optical amplifiers: performance and applications in optical packet switching [Invited]

Semiconductor optical amplifiers (SOAs) are a versatile core technology and the basis for the implementation of a number of key functionalities central to the evolution of highly wavelength-agile all-optical networks. We present an overview of the state of the art of SOAs and summarize a range of applications such as power boosters, preamplifiers, optical linear (gain-clamped) amplifiers, optical gates, and modules based on the hybrid integration of SOAs to yield high-level functionalities such as all-optical wavelength converters/regenerators and small space switching matrices. Their use in a number of proposed optical packet switching situations is also highlighted

The trajectory to diagnosis with pulmonary arterial hypertension: a qualitative study

Objectives To investigate the patient's experience of the trajectory to receiving a diagnosis of pulmonary arterial hypertension (PAH) and inform the provision of care for this patient group. Design Qualitative study using in-depth one-to-one interviews and pictorial representations. Data were analysed using thematic analysis. Setting Participants were interviewed in their own homes across England. Participants 30 patients with a diagnosis of pulmonary hypertension (18 participants were women, mean age 56 and range 26-80 02years and time since diagnosis ranged from a few months to more than 12 02years) participated. Results All participants, regardless of the time since diagnosis, vividly described the process from manifestation of symptoms to receiving a confirmed diagnosis. The authors present data using three major themes: (i) making sense of symptoms, (ii) process of elimination and (iii) being diagnosed with PAH. Making sense of symptoms represented an early period of perseverance 14people tried to carry-on as usual despite 18unexplained breathlessness 19. As time progressed, this period was punctuated by critical events that triggered seeking medical advice. Once medical contact had been made, patients described a period of 18elimination 19 and convoluted contact with the medical profession. Dyspnoea misdiagnosis was a key factor that delayed the PAH diagnosis. Diagnosis disclosure by some medical professionals was also viewed as lacking empathy. More positive experiences were relayed when the medical team disclosing the diagnosis acknowledged previous limitations. Conclusions A lack of awareness of this illness from both the sufferer themselves and the medical profession emerged as a central theme and led to prolonged periods of being misdiagnosed. The application of a diagnostic pathway for unexplained dyspnoea that alerts practitioners to rare conditions could expedite the process of correct diagnosis

Calculation of the hyperfine structure of the superheavy elements Z=119 and Z=120+

The hyperfine structure constants of the lowest $s$ and $p_{1/2}$ states of superheavy elements Z=119 and Z= 120$^+$ are calculated using {\em ab initio} approach. Core polarization and dominating correlation effects are included to all orders. Breit and quantum electrodynamic effects are also considered. Similar calculations for Cs, Fr, Ba$^+$ and Ra$^+$ are used to control the accuracy. The dependence of the hyperfine structure constants on nuclear radius is discussed.Comment: 4 pages, 3 tables, no figure

Some Ovid of the Films : W. B. Yeats, Mass Media, and the Future of Poetry in the 1930s

This essay addresses Yeats’s negotiation of poetry’s relationship, during the 1930s, with the emerging mass culture. Rather than contextualizing Yeats’s view on the future with a traditional critical framework such as Romantic apocalyptical discourse, a closeness to Aldous Huxley’s Brave New World and dystopian novels is explored. The main focus is on an unfinished draft for A Vision, “Michael Robartes Foretells,” and the way it envisages the changing situation for literature at the end of an epoch. Yeats’s use of classical parallels and linking of poetry and cinema are given special attention. His suggestion that the poetry of the future may be affected by the emergent medium of cinema provides an ambivalent perspective, not simply suggesting the degeneration of poetry in a context of Americanized mass culture but also possibilities of metamorphosis and spirituality. The interpretation of “Michael Robartes Foretells” is framed by other examples of Yeats’s engagement with mass media in the 1930s, in the form of Virginia Woolf’s diary report of table talk and Yeats’s radio broadcasts. All in all, Yeats’s view on poetry’s position balances between a conservative fear of marginalization and a more hopeful view of its potential to reinvent itself in a new historical context

Characteristics, of TIROS, GOES, DMSP and LANDSAT Systems

The characteristics of the TIROS, GOES, DMSP and LANDSAT systems of satellites are described. The data listed for each system are altitude of orbit, inclination/position, orbit type, orbits per day, expected operational lifetime and the sensor systems. The sensor systems are described as to wavelength of each channel, resolution, field of view and other pertinent information. Data information such as availability rate, collection method, primary use/application and how to obtain additional information is also given

Recognition and Dissimulation: Nationalism and Genre in James Clarence Mangan's 'The Lovely Land'

James Clarence Mangan has been celebrated by James Joyce and W. B. Yeats as one of the preeminent Irish writers of the nineteenth century. This essay interprets his poem ‘The Lovely Land’, first printed in The Nation on 18 July 1846, in terms of genre and nationalism. In an early Irish example of ekphrasis, the poem stages a rhetorical misreading where the speaker mistakes an unnamed Irish landscape of Daniel Maclise’s for a painting by Veronese or  Poussin. Where – among his English and German Romantic predecessors – might Mangan have found a precedent for the poem’s treatment of landscape? And how does the colonial relationship between Ireland and England fit in with the poem’s complex manoeuvring of different national iconographies? In seeking to answer these questions, this essay looks tofurther the ‘mapping’ of Mangan’s position in Romanticism as an international movement

Low power laser generated ultrasound : signal processing for time domain data acquisition

The use of low power modulated laser diode systems has previously been established as a suitable method for non-destructive laser generation of ultrasound. Using a quasi-continuous optical excitation amplified by an erbium-doped fibre amplifier (EDFA) allows flexible generation of ultrasonic waves, offering control of further parameters such as the frequency content or signal shape. In addition, pseudo-random binary sequences (PRBS) can be used to improve the detected impulse response. Here we compare two sequences, the m-sequence and the Golay code, and discuss the advantages and practical limits of their application with laser diode based optical excitation of ultrasound