Quasi-phasematching of harmonic generation via multimode beating in waveguides

A new scheme for quasi-phasematching high harmonic generation (HHG) in gases is proposed. In this, the rapid variation of the axial intensity resulting from excitation of more than one mode of a waveguide is used to achieve quasi phasematching. Numerical modeling demonstrates enhancement of the harmonic signal over that achieved for a single coherence length by factors > 10(4). (C) 2007 Optical Society of America

An Inconvenient Truth: Barriers to Truth Recovery in the Aftermath of Institutional Child Abuse in Ireland

Contemporary settled democracies, including the United States, England and Wales and Ireland, have witnessed a string of high profile cases of institutional child abuse in both church and state settings. Set against the broader literature on transitional justice, this analysis argues that there are significant barriers to truth recovery within the particular context of historical institutional abuse by the clergy in the Republic of Ireland. In the main, I argue that the frameworks of the inquiries and commissions into historical institutional child abuse are not conducive to truth recovery or the search for justice in dealing with the legacy of an abusive past. It is the church-state relationship which makes the Irish situation noteworthy and unique. The Catholic Church and child care institutions are especially self-protective, secretive and closed by nature and strongly discourage the drawing of attention to any deficiencies in organisational procedures. The nature of the public inquiry process also means that there is often a rather linear focus on accountability and apportioning blame. Collectively, such difficulties inhibit fuller systemic investigation of the veracity of what actually happened and, in turn, meaningful modification of child care policies. The article concludes by offering some thoughts on implications for transitional justice discourses more broadly as well as the residual issues for Ireland and other settled democracies in terms of moving on from the legacy of institutional child abuse.

'Securing' the past: Policing and the contest over truth in Northern Ireland

The question of whether Northern Ireland should have a formal truth recovery process has been amplified by the recent Report of the Consultative Group on the Past. Compared to the volume at which the truth recovery debate has been played out, relatively little is known about policing attitudes to this form of dealing with the past. This paper analyses the ways in which the history and context of policing in Northern Ireland have shaped attitudes towards truth recovery. It will be argued that differing opinions on the need for truth recovery are part of a debate over 'ownership of the past' between the ardent supporters of the Royal Ulster Constabulary and the new post-Patten managers and modernizers.

Denial, Silence and the Politics of the Past: Unpicking the Opposition to Truth Recovery in Northern Ireland

There has been considerable and protracted debate on whether a formal truth recovery process should be established in Northern Ireland. Some of the strongest opposition to the creation of such a body has been from unionist political elites and the security forces. Based on qualitative fieldwork, this article argues that the dynamics of denial and silence have been instrumental in shaping their concerns. It explores how questions of memory, identity and denial have created a ‘myth of blamelessness’ in unionist discourse that is at odds with the reasons for a truth process being established. It also examines how three interlocking manifestations of silence – ‘silence as passivity,’ ‘silence as loyalty’ and ‘silence as pragmatism’ – have furthered unionists’ opposition to dealing with the past. This article argues that making peace with the past requires an active deconstruction of these practices.

Generation of a quasi-monoergetic proton beam from laser-irradiated sub-micron droplets

Proton bursts with a narrow spectrum at an energy of (2.8 +/- 0.3 MeV) are accelerated from sub-micron water spray droplets irradiated by high-intensity (similar to 5 x 10(19)W/cm(2)), high-contrast (similar to 10(10)), ultra-short (40 fs) laser pulses. The acceleration is preferentially in the laser propagation direction. The explosion dynamics is governed by a residual ps-scale laser pulse pedestal which "mildly" preheats the droplet and changes its density profile before the arrival of the high intensity laser pulse peak. As a result, the energetic electrons extracted from the modified target by the high-intensity part of the laser pulse establish an anisotropic electrostatic field which results in anisotropic Coulomb explosion and proton acceleration predominantly in the forward direction. Hydrodynamic simulations of the target pre-expansion and 3D particle-in-cell simulations of the measured energy and anisotropy of the proton emission have confirmed the proposed acceleration scenario. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4731712]

Refractory cachexia and truth-telling about terminal prognosis; A qualitative study

The purpose of this paper is to examine the consequences that medical practitioners’ decisions about whether or not to be candid about terminal prognosis have for those suffering from refractory cachexia and their families. It presents the findings of a qualitative study which used focus groups and semi-structured interviews of a volunteer sample of doctors, nurses and dieticians in a cancer centre of a large teaching hospital in Northern Ireland. Respondents reported that some physicians tended to avoid discussing terminal prognosis in a direct manner with their patients. Nurses and dieticians tended to be reluctant to engage in conversations about weight loss with patients with cachexia. One of the reasons they reported for their lack of acknowledgement of weight loss concerned the close association between refractory cachexia and terminal prognosis. Because they viewed the telling of bad news as an exclusive prerogative of medical practitioners, they did not feel in a position to discuss cachexia because they were concerned that this had the potential to raise end-of-life issues that lay outside the boundaries of their professional role. This meant patients and their families were provided with little information about how to cope with the distressing consequences of cachexia.

Job search monitoring intensity, unemployment exit and job entry: Quasi-experimental evidence from the UK

Because unemployment benefit reforms tend to package together changes to job search requirements, monitoring and assistance, few existing studies have been able to empirically isolate the effects of job search monitoring intensity on the behaviour of unemployment benefit claimants. This paper exploits periods where monitoring has been temporarily withdrawn during a series of Benefit Office refurbishments - with the regime otherwise unchanged - to allow such identification. During these periods of zero monitoring the hazard rates for exits from claimant unemployment and for job entry both fall. © 2008 Elsevier B.V. All rights reserved.