Probing Ferroelectrics Using Optical Second Harmonic Generation

Nonlinear optics is an essential component of modern laser systems and optoelectronic devices. It has also emerged as an important tool in probing the electronic, vibrational, magnetic, and crystallographic structure of materials ranging from oxides and metals, to polymers and biological samples. This review focuses on the specific technique of optical second harmonic generation (SHG), and its application in probing ferroelectric complex oxide crystals and thin films. As the dominant SHG interaction mechanism exists only in materials that lack inversion symmetry, SHG is a sensitive probe of broken inversion symmetry, and thus also of bulk polar phenomena in materials. By performing in-situ SHG polarimetry experiments in different experimental conditions such as sample orientation, applied electric field, and temperature, one can probe ferroelectric hysteresis loops and phase transitions. Careful modeling of the polarimetry data allows for the determination of the point group symmetry of the crystal. In epitaxial thin films with a two-dimensional arrangement of well-defined domain orientations, one can extract information about intrinsic material properties such as nonlinear coefficients, as well as microstructural information such as the local statistics of the different domain variants being probed. This review presents several detailed examples of ferroelectric systems where such measurements and modeling are performed. The use of SHG microscopic imaging is discussed, and its ability to reveal domain structures and phases not normally visible with linear optics is illustrated.

Deriving the Edge: What's in a phase?

This article offers a critical conceptual discussion and refinement of Chomsky’s (2000, 2001, 2007, 2008) phase system, addressing many of the problematic aspects highlighted in the critique of Boeckx & Grohmann (2007) and seeking to resolve these issues, in particular the stipulative and arbitrary properties of phases and phase edges encoded in the (various versions of the) Phase Impenetrability Condition (PIC). Chomsky’s (2000) original conception of phases as lexical subarrays is demonstrated to derive these properties straightforwardly once a single assumption about the pairwise composition of phases is made, and the PIC is reduced to its necessary core under the Strong Minimalist Thesis (SMT)—namely, the provision of an edge. Finally, a comparison is undertaken of the lexical-subarray conception of phases with the feature-inheritance system of Chomsky 2007, 2008, in which phases are simply the locus of uninterpretable features (probes). Both conceptions are argued to conform to the SMT, and both converge on a pairwise composition of phases. However, the two conceptions of phases are argued to be mutually incompatible in numerous fundamental ways, with no current prospect of unification. The lexical-subarray conception of phases is then to be preferred on grounds of greater empirical adequacy.

Hardware Comparison of the ISO/IEC 29192-2 Block Ciphers

As ubiquitous computing becomes a reality, sensitive information is increasingly processed and transmitted by smart cards, mobile devices and various types of embedded systems. This has led to the requirement of a new class of lightweight cryptographic algorithm to ensure security in these resource constrained environments. The International Organization for Standardization (ISO) has recently standardised two low-cost block ciphers for this purpose, Clefia and Present. In this paper we provide the first comprehensive hardware architecture comparison between these ciphers, as well as a comparison with the current National Institute of Standards and Technology (NIST) standard, the Advanced Encryption Standard.

Marie Sallé as muse, Handel's music for mime

Considers Handel's musical response to a dancer-choreographer in line with then-current styles of dance

Evaluation of a Final Year Work-shadowing Attachment

The transition from medical student to junior doctor is well recognised to be a difficult and stressful period. To ease this transition, most UK universities have a work-shadowing period (WSP), during which students can learn practical skills needed for forthcoming employment. The aim of this study was to evaluate the WSP at Queen's University Belfast, and gain the views of both students and Foundation Programme Supervisors and Directors (FPSDs). The study utilised both qualitative (focus groups) and quantitative (questionnaires) approaches. The FPSDs completed a specific questionnaire designed for this study, while the students completed the university's internal quality assurance questionnaire. Twenty-eight of the 37 (76%) FPSDs and 106 / 196 (54%) students completed the questionnaires. Focus groups were conducted with up to 10 students in each group in both a regional centre and a district general hospital at the start and the end of the WSP as well as 8 weeks into working life. The transcripts of the focus groups were analysed and themes identified. A number of deficiencies with the current WSP were identified, including concerns about the use of log books, the timing of the attachment and relatively low levels of supervision provided by senior hospital staff members. As a result, students felt unprepared for commencing work, with particular mention given to medical emergencies, prescribing, and the emotional aspects of the job. A number of recommendations are made, including the need for more senior input to ensure better student attendance, participation and clinical interaction. Furthermore, students should be offered additional supervised responsibility for delivery of patient care and more experiential learning with respect to drug prescribing and administration. The study also suggests that more needs to be done to help ease the emotional and psychological stresses of the early FY1 period. These issues have been resolved to a large extent with the introduction of the new final year Student Assistantship module in the academic year 2010-2011. © The Ulster Medical Society, 2012.

A population-based study of adverse physical effects following prostate cancer treatments: Results from the PiCTure (Prostate cancer treatment – your experience) study

Background:

Men and clinicians need reliable population based information when making decisions about investigation and treatment of prostate cancer. In the absence of clearly preferred treatments, differences in outcomes become more important.

Aim:

To investigate rates of adverse physical effects among prostate cancer survivors 2-15 years post diagnosis by treatment, and estimate population burden.

Methods:

A cross sectional, postal survey to 6,559 survivors (all ages) diagnosed with primary, invasive prostate cancer (ICD10-C61), identified in Northern Ireland and the Republic of Ireland via cancer registries. Questions included symptoms at diagnosis, treatments received and adverse physical effects (impotence, urinary incontinence, bowel problems, breast changes, libido loss, hot flashes, fatigue) experienced ‘ever’ and ‘current’ i.e. at questionnaire completion. Physical effect levels were weighted by age, country and time since diagnosis for all prostate cancer survivors. Bonferroni corrections were applied to account for multiple comparisons.

Results:

Adjusted response rate 54%, (n=3,348). 75% reported at least one current physical effect (90% ever), with 29% reporting at least three. These varied by treatment. Current impotence was reported by 76% post-prostatectomy, 64% post-external beam radiotherapy with hormone therapy, with average for all survivors of 57%. Urinary incontinence (overall current level: 16%) was highest post-prostatectomy (current 28%, ever 70%). 42% of brachytherapy patients reported no current adverse physical effects; however 43% reported current impotence and 8% current incontinence. Current hot flashes (41%), breast changes (18%) and fatigue (28%) were reported more commonly by patients on hormone therapy.

Conclusions:

This study provides evidence that adverse physical effects following prostate cancer represent a significant public health burden; an estimated 1.6% of men over 45 is a prostate cancer survivor with a current adverse physical effect. This information should facilitate investigation and treatment decision-making and follow-up care of patients.

Applying Health Locus of Control and Latent Class Modelling to food and physical activity choices affecting CVD risk

Health Locus of Control (HLC) classifies our beliefs about the connection between our actions and health outcomes (Skinner, 1996) into three categories: “internal control”, corresponding to health being the result of an individual's effort and habits; “control by powerful others”, whereby health depends on others, such as doctors; and “chance control”, according to which health depends on fate and chance. Using Choice Experiments we investigate the relationship between HLC and willingness to change lifestyle, in terms of eating habits, physical activity and associated cardiovascular disease risk, in a 384 person sample representative of the 40–65 aged population of Northern Ireland administered between February and July 2011. Using latent class analysis we identify three discrete classes of people based on their HLC: the first class is sceptical about their capacity to control their health and certain unhealthy habits. Despite being unsatisfied with their situation, they are reluctant to accept behaviour changes. The second is a group of individuals unhappy with their current situation but willing to change through exercise and diet. Finally, a group of healthy optimists is identified, who are satisfied with their current situation but happy to take more physical activity and improve their diet. Our findings show that any policy designed to modify people's health related behaviour should consider the needs of this sceptical class which represents a considerable proportion of the population in the region.

Health professionals' and service users' perspectives of shared care for monitoring wet age-related macular degeneration: a qualitative study alongside the ECHoES trial

Objectives: To explore the views of eye health professionals and service users on shared community and hospital care for wet or neovascular age-related macular degeneration (nAMD).

Method: Using maximum variation sampling, 5 focus groups and 10 interviews were conducted with 23 service users and 24 eye health professionals from across the UK (consisting of 8 optometrists, 6 ophthalmologists, 6 commissioners, 2 public health representatives and 2 clinical eye care advisors to local Clinical Commissioning Groups). Data were transcribed verbatim and analysed thematically using constant comparative techniques derived from grounded theory methodology.

Results: The needs and preferences of those with nAMD appear to be at odds with the current service being provided. There was enthusiasm among health professionals and service users about the possibility of shared care for nAMD as it was felt to have the potential to relieve hospital eye service burden and represent a more patient-centred option, but there were a number of perceived barriers to implementation. Some service users and ophthalmologists voiced concerns about optometrist competency and the potential for delays with referrals to secondary care if stable nAMD became active again. The health professionals were divided as to whether shared care was financially more efficient than the current model of care. Specialist training for optometrists, under the supervision of ophthalmologists, was deemed to be the most effective method of training and was perceived to have the potential to improve the communication and trust that shared care would require.

Conclusions: While shared care is perceived to represent a promising model of nAMD care, voiced concerns suggest that there would need to be greater collaboration between ophthalmology and optometry, in terms of interprofessional trust and communication.

Sandwich nanoarchitecture of LiV3O8/graphene multilayer nanomembranes via layer-by-layer self-assembly for long-cycle-life lithium-ion battery cathodes

A lack of suitable high-performance cathode materials has become the major barrier to their applications in future advanced communication equipment and electric vehicle power systems. In this paper, we have developed a layer-by-layer self-assembly approach for fabricating a novel sandwich nanoarchitecture of multilayered LiV₃O₈ nanoparticle/graphene nanosheet (M-nLVO/GN) hybrid electrodes for potential use in high performance lithium ion batteries by using a porous Ni foam as a substrate. The prepared sandwich nanoarchitecture of M-nLVO/GN hybrid electrodes exhibited high performance as a cathode material for lithium-ion batteries, such as high reversible specific capacity (235 mA h g^-1 at a current density of 0.3 A g^-1), high coulombic efficiency (over 98%), fast rate capability (up to a current density of 10 A g^-1), and superior capacity retention during cycling (90% capacity retention with a current density of 0.3 A g^-1 after 300 cycles). Very significantly, this novel insight into the design and synthesis of sandwich nanoarchitecture would extend their application to various electrochemical energy storage devices, such as fuel cells and supercapacitors.

Revisiting Iris Marion Young on Normalisation, Inclusion and Democracy

Vieten's edited collection brings together papers that were given at the I M Young Memorial Symposium 'Inclusion and Democracy Revisited', held in Amsterdam in 2012. The different chapters presented explore in-depth, Young's models of a 'politics of cultural difference', and a 'politics of positional difference' read in combination with her critique of normalisation. Young regards the latter as decisive to any change for the better when reaching out politically to a fairer and more just democratic society.
With the current political, economic and socio-cultural crisis in mind, the contemporary world of global speed and transformed societies in and beyond Europe needs a refinement of what we understand 'normalisation' and 'difference' to be. How can we connect to each other, and in what ways can Young's 'structural inequality model' be applied to develop alternative outlooks on how to enhance inclusion and democracy in different nation states?

Perspectives on social citizenship in the EU – from status positivus to status socialis activus via two forms of transnational solidarity

Ever since the inauguration of EU citizenship, elements of social citizenship have been on the agenda of European integration. European level social benefits were proposed early on, and demands for collective labour rights have followed suit. This chapter uses the theoretical umbrella of transnational social citizenship in order to link transnational access to social benefits and collective labour rights. It promotes transnational rights as the best way to conceptualise EU social citizenship as an institution enabling the enjoyment of EU integration without being forced to forego social rights at other levels. Such a perspective sits well in a collection on EU citizenship and federalism, since it simultaneously challenges demands of renationalisation of social rights in the EU and pleas to reduce EU-level citizenship rights to a merely liberal dimension. Social citizenship as promoted here requires an interactive conceptualisation of regulatory and judicial powers at different levels of government as typical for federal systems.
In linking citizenship with human rights the chapter highlights different statuses of citizens. It argues that the rights constituted by social citizenship derive from a status positivus and a status socialis activus, expanding the time-honoured categories of Jellinek. This concept is developed further by linking the notions of receptive solidarity to the status positivus and the notion of participative solidarity to the status socialis activus. In relation to European Union citizenship it promotes a sustainable transnational social citizenship catering for receptive and participative solidarity.
These ideas contrast with most current discourses on EU citizenship. The stress on social citizenship takes issue with a retreat to mere liberalist notions of EU-level citizenship, and the stress on rights takes issue with conceptualising EU citizenship as a community bond with obligations, downplaying the empowering potential of rights. The difficulty of conceptualising transnational social citizenship is to avoid, on the one hand, taking up the tune of populist discourses imagining those moving beyond state borders as a threat to national social citizenship and, on the other hand, to reject the legitimate fears of those remaining at home of creating rupture in the social fabric of Europe’s society. Promoting transnational social citizenship rights based on receptive and participative solidarity the present chapter aims to contribute to avoiding these pitfalls.

Molecular dynamics simulation investigation on the plastic flow behaviour of silicon during nanometric cutting

Molecular dynamics (MD) simulation was carried out to acquire an in-depth understanding of the flow behaviour of single crystal silicon during nanometric cutting on three principal crystallographic planes and at different cutting temperatures. The key findings were that (i) the substrate material underneath the cutting tool was observed for the first time to experience a rotational flow akin to fluids at all the tested temperatures up to 1200 K. (ii) The degree of flow in terms of vorticity was found higher on the (1 1 1) crystal plane signifying better machinability on this orientation in accord with the current pool of knowledge (iii) an increase in the machining temperature reduces the springback effect and thereby the elastic recovery and (iv) the cutting orientation and the cutting temperature showed significant dependence on the location of the stagnation region in the cutting zone of the substrate.

Vacuum birefringence in strong inhomogeneous electromagnetic fields

Birefringence is one of the fascinating properties of the vacuum of quantum electrodynamics (QED) in strong electromagnetic fields. The scattering of linearly polarized incident probe photons into a perpendicularly polarized mode provides a distinct signature of the optical activity of the quantum vacuum and thus offers an excellent opportunity for a precision test of nonlinear QED. Precision tests require accurate predictions and thus a theoretical framework that is capable of taking the detailed experimental geometry into account. We derive analytical solutions for vacuum birefringence which include the spatio-temporal field structure of a strong optical pump laser field and an x-ray probe. We show that the angular distribution of the scattered photons depends strongly on the interaction geometry and find that scattering of the perpendicularly polarized scattered photons out of the cone of the incident probe x-ray beam is the key to making the phenomenon experimentally accessible with the current generation of FEL/high-field laser facilities.

Personalised and Precision Medicine in Cancer Clinical Trials: Panacea for Progress or Pandora's Box?

Cancer clinical trials have been one of the key foundations for significant advances in oncology. However, there is a clear recognition within the academic, care delivery and pharmaceutical/biotech communities that our current model of clinical trial discovery and development is no longer fit for purpose. Delivering transformative cancer care should increasingly be our mantra, rather than maintaining the status quo of, at best, the often miniscule incremental benefits that are observed with many current clinical trials. As we enter the era of precision medicine for personalised cancer care (precision and personalised medicine), it is important that we capture and utilise our greater understanding of the biology of disease to drive innovative approaches in clinical trial design and implementation that can lead to a step change in cancer care delivery. A number of advances have been practice changing (e.g. imatinib mesylate in chronic myeloid leukaemia, Herceptin in erb-B2-positive breast cancer), and increasingly we are seeing the promise of a number of newer approaches, particularly in diseases like lung cancer and melanoma. Targeting immune checkpoints has recently yielded some highly promising results. New algorithms that maximise the effectiveness of clinical trials, through for example a multi-stage, multi-arm type design are increasingly gaining traction. However, our enthusiasm for the undoubted advances that have been achieved are being tempered by a realisation that these new approaches may have significant cost implications. This article will address these competing issues, mainly from a European perspective, highlight the problems and challenges to healthcare systems and suggest potential solutions that will ensure that the cost/value rubicon is addressed in a way that allows stakeholders to work together to deliver optimal cost-effective cancer care, the benefits of which can be transferred directly to our patients.

Impact of age, various forms of cataract, and visual acuity on whole-field scotopic sensitivity screening for glaucoma in rural Taiwan.

OBJECTIVE: To evaluate the impact of age, various forms of cataract, and visual acuity on whole-field scotopic sensitivity screening for glaucoma in a rural population. DESIGN: Clinic-based study with population-based recruitment. SETTING: Jin Shan Township near Taipei, Taiwan. SUBJECTS: Three hundred forty-six residents (ages, > or = 40 years) of Jin Shan Township. INTERVENTIONS: Whole-field scotopic testing, ophthalmoscopy with dilation of the pupils, cataract grading against photographic standards, and screening visual field testing in a random one-third subsample. MAIN OUTCOME MEASURES: Whole-field scotopic sensitivity (in decibels) and diagnostic status as a case of glaucoma, glaucoma suspect, or normal. RESULTS: Participants in Jin Shan Township did not differ significantly in the rate of blindness, low visual acuity, or family history of glaucoma from a random sample of nonrespondents. Scotopic sensitivity testing detected 100% (6/6) of subjects with open-angle glaucoma at a specificity of 80.2%. The mean +/- SE scotopic sensitivity for six subjects with open-angle glaucoma (32.78 +/- 1.51 dB) differed significantly from that of 315 normal individuals (38.51 +/- 0.22 dB), when adjusted for age and visual acuity (P = .05, t test). With linear regression modeling, factors that correlated significantly with scotopic sensitivity were intraocular pressure, screening visual field, best corrected visual acuity, presence of cortical cataract, and increasing age. CONCLUSIONS: Although cataract affects the whole-field scotopic threshold, it appears that scotopic testing may be of value in field-based screening for glaucoma.