Nonlinear Optics Quantum Computing with Circuit-QED

One approach to quantum information processing is to use photons as quantum bits and rely on linear optical elements for most operations. However, some optical nonlinearity is necessary to enable universal quantum computing. Here, we suggest a circuit-QED approach to nonlinear optics quantum computing in the microwave regime, including a deterministic two-photon phase gate. Our specific example uses a hybrid quantum system comprising a LC resonator coupled to a superconducting flux qubit to implement a nonlinear coupling. Compared to the self-Kerr nonlinearity, we find that our approach has improved tolerance to noise in the qubit while maintaining fast operation.Comment: 5 pages, 3 figure

Fixation failure in an isolated tibial eminence ACL traction avulsion fracture in a paratrooper: is there an association with vitamin D deficiency?

Tibial eminence avulsion fracture at the ACL footprint may be caused by high-energy forces such as a fall, in which the ACL ligament proves stronger than the forces that hold the bone together. For reasons of bone maturity however, tibial spine avulsion fractures where the ACL remains intact, typically occur in children but are rare in adults. This case demonstrates a rare type of adult tibial avulsion fracture with intact ACL and subsequent fragment fixation failure in which vitamin D deficiency may have been contributory. Because there is a high rate of inadequate vitamin D levels in patients undergoing orthopaedic surgery and a known impact on bone healing complications, post-operative bone fixation failure may also occur. This case report may therefore prompt further awareness for considering pre-surgical vitamin D deficiency screening in adults presenting with rare avulsion fractures, and may further demonstrate its impact on surgical outcomes

Creating citizen-consumers? Public service reform and (un)willing selves

About the book: Postmodern theories heralded the "death of the subject", and thereby deeply contested our intuition that we are free and willing selves. In recent times, the (free) will has come under attack yet again. Findings from the neuro- and cognitive sciences claim the concept of will to be scientifically untenable, specifying that it is our brain rather than our 'self' which decides what we want to do. In spite of these challenges however, the willing self has come to take centre stage in our society: juridical and moral practices ascribing guilt, or the organization of everyday life attributing responsibilities, for instance, can hardly be understood without taking recourse to the willing subject. In this vein, the authors address topics such as the genealogy of the concept of willing selves, the discourse on agency in neuroscience and sociology, the political debate on volition within neoliberal and neoconservative regimes, approaches toward novel forms of relational responsibility as well as moral evaluations in conceptualizing autonomy

"Do your eyes play tricks on you?” Asking older people about visual hallucinations in a general eye clinic

Visual hallucinations are well recognized in individuals with low vision and intact cognition (Charles Bonnet syndrome) (Teunisse et al., 1996). Visual hallucinations also occur in those with early manifestations of dementia with Lewy bodies (McKeith et al., 2005) and Parkinson's disease dementia (Williams and Lees, 2005). Typically, visual hallucinations in these conditions are complex recurrent hallucinations of people and animals and frequently reported as being unpleasant (Mosimann et al., 2006). Individuals with visual hallucinations are often reluctant to disclose details of their symptoms (Menon, 2005), but may instead report non-specific visual difficulties to their family physician or optometrist, resulting in referral to an eye clinic. Failure to elicit the presence of visual hallucinations may lead to inappropriate treatment of age-related ocular comorbidity, such as early catarac

26856 Proliferative nodule resembling angiomatoid Spitz with pronounced degenerative atypia arising within a giant congenital nevus

Proliferative nodules arising within congenital melanocytic nevi present a diagnostic challenge for dematopathologists given their close resemblance to melanoma. In difficult cases, ancillary molecular tests can be used to better exclude the possibility of malignancy. We report case of a biopsy and subsequent excision of an unusual proliferative nodule with overlapping features of angiomatoid Spitz tumor and ancient melanocytic nevus which demonstrated normal findings on both chromosomal microarray and a gene expression profiling assay. Our case is noteworthy given its striking resemblance to what has been reported for an angiomatoid Spitz tumor. To our knowledge, this particular morphologic subset of Spitz has been described primarily in the context of spontaneous melanocytic tumors arising de novo outside the context of a congenital lesion. The pathology showed bizarre cytological features along with a myxoid and highly vascularized stroma which is thought to represent degenerative atypia characteristic of an “ancient nevus.” The lesions described as ancient nevi have some overlapping stromal features with angiomatoid Spitz tumors. A low proliferation index and paucity of mitotic figures is characteristic of these neoplasms. We hypothesize that continued host response to the lesion may be responsible for inducing the observed cytological and stromal derangement. Interestingly, these changes increased from the time of biopsy to the excision. Future studies should aim to define the genetic and immunologic signature of these lesions to help predict prognosis. The relationship between angiomatoid Spitz tumor, ancient change, and regressing nevi should also be investigated

Extending the diabetic retinopathy screening interval beyond 1 year : systematic review

To determine whether the recommended screening interval for diabetic retinopathy (DR) in the UK can safely be extended beyond 1 year. Systematic review of clinical and cost-effectiveness studies. Nine databases were searched with no date restrictions. Randomised controlled trials (RCTs), cohort studies, prognostic or economic modelling studies which described the incidence and progression of DR in populations with type 1 diabetes mellitus or type 2 diabetes mellitus of either sex and of any age reporting incidence and progression of DR in relation to screening interval (vs annual screening interval) and/or prognostic factors were included. Narrative synthesis was undertaken. 14 013 papers were identified, of which 11 observational studies, 5 risk stratification modelling studies and 9 economic studies were included. Data were available for 262 541 patients of whom at least 228 649 (87%) had type 2 diabetes. There were no RCTs. Studies concluded that there is little difference between clinical outcomes from screening 1 yearly or 2 yearly in low-risk patients. However there was high loss to follow-up (13–31%), heterogeneity in definitions of low risk and variation in screening and grading protocols for prior retinopathy results. Observational and economic modelling studies in low-risk patients show little difference in clinical outcomes between 1-year and 2-year screening intervals. The lack of experimental research designs and heterogeneity in definition of low risk considerably limits the reliability and validity of this conclusion. Cost-effectiveness findings were mixed. There is insufficient evidence to recommend a move to extend the screening interval beyond 1 year

Measuring spatial pressure distribution from explosives buried in dry Leighton Buzzard sand

Direct measurement of the intense loading produced by the detonation of a buried explosive is an extremely difficult task. Historically, high-fidelity measurement techniques have not been sufficiently robust to capture the extremely high pressures associated with such events, and researchers have relied on ‘global’ measurements such as the average loading acting over a particular area of interest. Recently, a large-scale experimental approach to the direct measurement of the spatial and temporal variation in loading resulting from an explosive event has been developed, which utilises Hopkinson pressure bars (HPBs) inserted through holes in a large target plate such that their faces lie flush with the loaded face. This article presents results from ten experiments conducted at 1/4 scale, using 17 HPBs to measure the spatial pressure distribution from explosives buried in dry Leighton Buzzard sand, a commonly available sand used in many geotechnical applications. Localised pressure measurements are used in conjunction with high speed video to provide a detailed examination of the physical processes occurring at the loaded face, as well allowing quantification of these effects. Example pressure–time and impulse–time traces are provided in full to allow researchers to use this data for validation of numerical modelling approaches

Exponential Decay of Correlations in a Model for Strongly Disordered 2D Nematic Elastomers

Lattice Monte-Carlo simulations were performed to study the equilibrium ordering in a two-dimensional nematic system with quenched random disorder. When the disordering field, which competes against the aligning effect of the Frank elasticity, is sufficiently strong, the long-range correlation of the director orientation is found to decay as a simple exponential, Exp[-r/x]. The correlation length {x} itself also decays exponentially with increasing strength of the disordering field. This result represents a new type of behavior, distinct from the Gaussian and power-law decays predicted by some theories.Comment: Latex file (4 pages) + 2 EPS figure

The intracluster magnetic field power spectrum in Abell 2382

The goal of this work is to put constraints on the strength and structure of the magnetic field in the cluster of galaxies A2382. We investigate the relationship between magnetic field and Faraday rotation effects in the cluster, using numerical simulations as a reference for the observed polarization properties. For this purpose we present Very Large Array observations at 20 cm and 6 cm of two polarized radio sources embedded in A2382, and we obtained detailed rotation measure images for both of them. We simulated random three-dimensional magnetic field models with different power spectra and thus produced synthetic rotation measure images. By comparing our simulations with the observed polarization properties of the radio sources, we can determine the strength and the power spectrum of intra-cluster magnetic field fluctuations that best reproduce the observations. The data are consistent with a power law magnetic field power spectrum with the Kolmogorov index $n=11/3$, while the outer scale of the magnetic field fluctuations is of the order of 35 kpc. The average magnetic field strength at the cluster center is about 3 $\mu$G and decreases in the external region as the square root of the electron gas density. The average magnetic field strength in the central 1 Mpc$^{3}$ is about 1 $\mu$G.Comment: Comments: 18 pages, 13 figures, accepted by A&A. For a version with high quality figures, see http://erg.ca.astro.it/preprints/guidetti2007