The search for spontaneous edge currents in Sr2RuO4 mesa structures with controlled geometrical shapes.

Scanning Hall microscopy has been used to search for spontaneous edge fields in geometrically shaped mesa structures etched into the ab surface of Sr2RuO4 single crystals in order to test recent theories of the direction of edge current flow as a function of facet orientation and band filling. We find no evidence for spontaneous edge fields in any of our mesa structures above our experimental noise floor of ± 25 mG. We do, however, observe pronounced vortex clustering at low fields and temperatures, consistent with the established semi-Meissner scenario whereby a long range attractive component to the vortex-vortex interaction arises due, for example, to the multiband nature of the superconductivity. We also see clear evidence for the formation of a square vortex lattice inside square mesa structures above 1.3 K. Our results are discussed in terms of recent relevant experimental results and theoretical predictions.

Tuning the structure of the Josephson vortex lattice in Bi2Sr2CaCu2O8+δ single crystals with pancake vortices.

In extremely anisotropic cuprate superconductors a lattice of stacks of pancake vortices nucleates when a magnetic field is applied perpendicular to the copper oxide layers, while an orthogonal lattice of highly elliptical Josephson vortices forms when the applied field is parallel to the layers. Under tilted magnetic fields these sublattices can interact in complex ways to form systems of vortex chains and composite vortex lattices. Here we have used high-resolution scanning Hall microscopy (SHM) to map the rich tilted-field vortex phase diagram in an underdoped Bi2Sr2CaCu2O8+δ single crystal. We find that the Josephson vortex lattice spacing has an unexpected non-monotonic dependence on the pancake vortex density reflecting the delicate balance between attractive and repulsive vortex interactions, and actually undergoes a field-driven structural transformation with increasing out-of-plane fields. We also identify particularly stable composite structures composed of vortex chains separated by an integer number of rows of interstitial pancake vortex stacks and are able to establish the precise evolution of vortex-chain phases as the out-of-plane field is increased at small in-plane fields. Our results are in good semi-quantitative agreement with theoretical models and could enable the development of vortex ratchets and lenses based on the interactions between Josephson and pancake vortices.

Probing the spiral magnetic phase in 6 nm textured erbium using polarised neutron reflectometry.

We characterise the magnetic state of highly-textured, sputter deposited erbium for a film of thickness 6 nm. Using polarised neutron reflectometry it is found that the film has a high degree of magnetic disorder, and we present some evidence that the film's local magnetic state is consistent with bulk-like spiral magnetism. This, combined with complementary characterisation techniques, show that thin film erbium is a strong candidate material for incorporation into device structures.

Magnetic Phases of Sputter Deposited Thin-Film Erbium.

We present a detailed structural and magnetic characterization of sputter deposited thin film erbium, determined by x-ray diffraction, transport measurements, magnetometry and neutron diffraction. This provides information on the onset and change of the magnetic state as a function of temperature and applied magnetic field. Many of the features of bulk material are reproduced. Also of interest is the identification of a conical magnetic state which repeats with a wavevector parallel to the c axis τc = 4/17 in units of the reciprocal lattice parameter c*, which is a state not observed in any other thin film or bulk measurements. The data from the various techniques are combined to construct magnetic field, temperature (H, T)-phase diagrams for the 200 nm-thick Er sample that serves as a foundation for future exploitation of this complex magnetic thin film system.

Placental findings associated with maternal obesity at early pregnancy.

INTRODUCTION: Obesity during pregnancy is associated with a wide spectrum of maternal, fetal and neonatal complications. This study compared placental pathology in women with obesity and normal weight gravidas. MATERIALS AND METHODS: This is a retrospective case-control study. The sample was randomly selected from a total of 1000 deliveries of largely Caucasian population in a single institution, recruited for the study of sleep disordered breathing, where the placenta is submitted for pathological examination for clinical indications based on national guidelines. Cases (Body mass index - BMI ≥ 30 kg/m(2); n = 47) and controls (BMI < 25 kg/m(2), n = 45) were selected based on BMI obtained from the first prenatal visit. Placental pathology, clinical parameters and limited outcomes were extracted from medical records. Placental weight range was defined as small for gestational age (SGA) if < 10th percentile, large for gestational age (LGA) if > 90th percentile. RESULTS: Mean BMI was 36.2 ± 5.5 in the group with obesity and 21.7 ± 1.9 in the control group (p < 0.01). There was a significantly higher prevalence of diabetes in cases compared to controls (14/47 vs. 3/45, p = 0.006) while preterm birth was significantly higher in the control group (9/47 vs. 19/46, p = 0.02). There were more LGA placentas in cases versus controls (12/47 vs. 2/46, p = 0.007; even after adjusting for diabetes). More histological features of inflammation, marginal insertion of the umbilical cord and intervillous thrombi in the parenchyma were also noted in the case group. CONCLUSIONS: Results from the current study suggest that maternal obesity measured at early pregnancy may have effects on both placental implantation and growth, and further exacerbate the hypercoagulable state in placenta.

Spontaneous symmetry breaking in vortex systems with two repulsive lengthscales.

Scanning Hall probe microscopy (SHPM) has been used to study vortex structures in thin epitaxial films of the superconductor MgB2. Unusual vortex patterns observed in MgB2 single crystals have previously been attributed to a competition between short-range repulsive and long-range attractive vortex-vortex interactions in this two band superconductor; the type 1.5 superconductivity scenario. Our films have much higher levels of disorder than bulk single crystals and therefore both superconducting condensates are expected to be pushed deep into the type 2 regime with purely repulsive vortex interactions. We observe broken symmetry vortex patterns at low fields in all samples after field-cooling from above Tc. These are consistent with those seen in systems with competing repulsions on disparate length scales, and remarkably similar structures are reproduced in dirty two band Ginzburg-Landau calculations, where the simulation parameters have been defined by experimental observations. This suggests that in our dirty MgB2 films, the symmetry of the vortex structures is broken by the presence of vortex repulsions with two different lengthscales, originating from the two distinct superconducting condensates. This represents an entirely new mechanism for spontaneous symmetry breaking in systems of superconducting vortices, with important implications for pinning phenomena and high current density applications.

Circular polarization in the optical afterglow of GRB 121024A.

Gamma-ray bursts (GRBs) are most probably powered by collimated relativistic outflows (jets) from accreting black holes at cosmological distances. Bright afterglows are produced when the outflow collides with the ambient medium. Afterglow polarization directly probes the magnetic properties of the jet when measured minutes after the burst, and it probes the geometric properties of the jet and the ambient medium when measured hours to days after the burst. High values of optical polarization detected minutes after the burst of GRB 120308A indicate the presence of large-scale ordered magnetic fields originating from the central engine (the power source of the GRB). Theoretical models predict low degrees of linear polarization and no circular polarization at late times, when the energy in the original ejecta is quickly transferred to the ambient medium and propagates farther into the medium as a blast wave. Here we report the detection of circularly polarized light in the afterglow of GRB 121024A, measured 0.15 days after the burst. We show that the circular polarization is intrinsic to the afterglow and unlikely to be produced by dust scattering or plasma propagation effects. A possible explanation is to invoke anisotropic (rather than the commonly assumed isotropic) electron pitch-angle distributions, and we suggest that new models are required to produce the complex microphysics of realistic shocks in relativistic jets.

An extremely luminous panchromatic outburst from the nucleus of a distant galaxy.

Variable x-ray and γ-ray emission is characteristic of the most extreme physical processes in the universe. We present multiwavelength observations of a unique γ-ray-selected transient detected by the Swift satellite, accompanied by bright emission across the electromagnetic spectrum, and whose properties are unlike any previously observed source. We pinpoint the event to the center of a small, star-forming galaxy at redshift z = 0.3534. Its high-energy emission has lasted much longer than any γ-ray burst, whereas its peak luminosity was ∼100 times higher than bright active galactic nuclei. The association of the outburst with the center of its host galaxy suggests that this phenomenon has its origin in a rare mechanism involving the massive black hole in the nucleus of that galaxy.

Gene therapy in the second eye of RPE65-deficient dogs improves retinal function.

The purpose of this study was to evaluate whether immune responses interfered with gene therapy rescue using subretinally delivered recombinant adeno-associated viral vector serotype 2 carrying the RPE65 cDNA gene driven by the human RPE65 promoter (rAAV2.hRPE65p.hRPE65) in the second eye of RPE65-/- dogs that had previously been treated in a similar manner in the other eye. Bilateral subretinal injection was performed in nine dogs with the second eye treated 85-180 days after the first. Electroretinography (ERG) and vision testing showed rescue in 16 of 18 treated eyes, with no significant difference between first and second treated eyes. A serum neutralizing antibody (NAb) response to rAAV2 was detected in all treated animals, but this did not prevent or reduce the effectiveness of rescue in the second treated eye. We conclude that successful rescue using subretinal rAAV2.hRPE65p.hRPE65 gene therapy in the second eye is not precluded by prior gene therapy in the contralateral eye of the RPE65-/- dog. This finding has important implications for the treatment of human LCA type II patients.

Profile of volatile compounds during papaya juice fermentation by a mixed culture of Saccharomyces cerevisiae and Williopsis saturnus.

This study investigated the formation and utilization of volatile compounds during papaya juice fermentation by a mixed culture of Saccharomyces cerevisiae and Williopsis saturnus. Time-course papaya juice fermentations were carried out using pure cultures of S. cerevisiae var. bayanus R2 and W. saturnus var. mrakii NCYC2251 and a mixed culture of the two yeasts at a ratio of 1:1000 (R2:NCYC2251). Changes in S. cerevisiae cell population, Brix, sugar consumption and pH were similar in the mixed culture and in the S. cerevisiae monoculture. There was an early growth arrest of W. saturnus in the mixed culture fermentation. A range of volatile compounds were produced during fermentation including fatty acids, alcohols, aldehydes and esters and some volatile compounds including those initially present in the juice were utilized. The mixed culture fermentation of S. cerevisiae and W. saturnus benefited from the presence of both yeasts, with more esters being produced than the S. cerevisiae monoculture and more alcohols being formed than the W. saturnus monoculture. The study suggests that papaya juice fermentation with a mixed culture of S. cerevisiae and W. saturnus may be able to result in the formation of more complex aroma compounds and higher ethanol level than those using single yeasts.

Orf: contagious pustular dermatitis.

Orf is a common viral infection in sheep. It spreads to humans by direct contact. It is self-limiting, treatment having no beneficial effect. Misdiagnosis by those unfamiliar with its characteristic features is common, and may result in unnecessary treatment with antibiotics or surgery. We present a series of five cases of Orf in children of farmers in the west of Ireland, seen over a 10 year period.

Delayed presentation following accidental inhalation of a pushpin.

A previously fit and well 18-year-old woman presented to the accident and emergency department following referral by her general practitioner with a provisional diagnosis of appendicitis. The history obtained from the patient revealed the presence of a bitemporal headache with associated neck stiffness, photophobia and vomiting for approximately 1.5 weeks. The patient complained of abdominal pain localised to her right iliac fossa and anorexia for approximately 1 week. She also noted the presence of a cough productive of green sputum for 3 weeks. A chest radiograph was obtained which showed a large area of consolidation in the right lower lobe consistent with infection and a linear density in keeping with a metallic foreign body. Following review of the chest radiograph, the patient was interviewed further and recalled having inhaled a pushpin approximately 1 year before her presentation. Aspiration of foreign bodies is relatively common in children and is often associated with delayed diagnosis and high morbidity. To prevent delayed diagnosis, characteristic symptoms and clinical and radiological signs of foreign body aspiration should be checked in all suspected cases and a low index of suspicion for ordering additional imaging or using bronchoscopy for diagnostic purposes should be employed.

Broadband observations of the naked-eye gamma-ray burst GRB 080319B.

Long-duration gamma-ray bursts (GRBs) release copious amounts of energy across the entire electromagnetic spectrum, and so provide a window into the process of black hole formation from the collapse of massive stars. Previous early optical observations of even the most exceptional GRBs (990123 and 030329) lacked both the temporal resolution to probe the optical flash in detail and the accuracy needed to trace the transition from the prompt emission within the outflow to external shocks caused by interaction with the progenitor environment. Here we report observations of the extraordinarily bright prompt optical and gamma-ray emission of GRB 080319B that provide diagnostics within seconds of its formation, followed by broadband observations of the afterglow decay that continued for weeks. We show that the prompt emission stems from a single physical region, implying an extremely relativistic outflow that propagates within the narrow inner core of a two-component jet.

Disaggregating the distal, proximal, and time-varying effects of parent alcoholism on children's internalizing symptoms.

We tested whether children show greater internalizing symptoms when their parents are actively abusing alcohol. In an integrative data analysis, we combined observations over ages 2 through 17 from two longitudinal studies of children of alcoholic parents and matched controls recruited from the community. Using a mixed modeling approach, we tested whether children showed elevated mother- and child-reported internalizing symptoms (a) at the same time that parents showed alcohol-related consequences (time-varying effects), (b) if parents showed greater alcohol-related consequences during the study period (proximal effects), and (c) if parents had a lifetime diagnosis of alcoholism that predated the study period (distal effects). No support for time-varying effects was found; proximal effects of mothers' alcohol-related consequences on child-reported internalizing symptoms were found and distal effects of mother and father alcoholism predicted greater internalizing symptoms among children of alcoholic parents. Implications for the time-embedded relations between parent alcoholism and children's internalizing symptoms are discussed.

Externalizing symptoms among children of alcoholic parents: Entry points for an antisocial pathway to alcoholism.

The authors examined heterogeneity in risk for externalizing symptoms in children of alcoholic parents, as it may inform the search for entry points into an antisocial pathway to alcoholism. That is, they tested whether the number of alcoholic parents in a family, the comorbid subtype of parental alcoholism, and the gender of the child predicted trajectories of externalizing symptoms over the early life course, as assessed in high-risk samples of children of alcoholic parents and matched controls. Through integrative analyses of 2 independent, longitudinal studies, they showed that children with either an antisocial alcoholic parent or 2 alcoholic parents were at greatest risk for externalizing symptoms. Moreover, children with a depressed alcoholic parent did not differ from those with an antisocial alcoholic parent in reported symptoms. These findings were generally consistent across mother, father, and adolescent reports of symptoms; child gender and child age (ages 2 through 17); and the 2 independent studies examined. Multialcoholic and comorbid-alcoholic families may thus convey a genetic susceptibility to dysregulation along with environments that both exacerbate this susceptibility and provide few supports to offset it.

Necessity breeds invention: a study of outpatient management of low velocity gunshot wounds.

BACKGROUND: Since the late 1980s, the emergency department (ED) at the Mater Hospital, Belfast, has implemented a policy of treating conservatively patients who sustain low velocity gunshot wounds to the lower limbs. Wounds are cleaned and minimally debrided under local anaesthetic in the ED. Patients are given oral antibiotics, and reviewed 48 hours later at the ED review clinic. OBJECTIVE: To investigate the outcome of outpatient ED management of low velocity gunshot wounds to the lower limbs. METHOD: This was a retrospective, observational study from January 2000 to September 2004 inclusive. Notes were retrieved of those patients who had gunshot wound mentioned in the triage text. Patients were included if they presented with a low velocity gunshot wound to the lower limbs. Demographics and treatment regimen were recorded. RESULTS: In total, 90 patients sustained low energy injuries to the lower limb, with 70.5% of wounds involving the skin and soft tissue only. Most patients (n = 67) were treated as outpatients, which included 80% of unilateral injuries and 46.6% of bilateral injuries presented. There were 56 patients reviewed at clinic. Three patients developed minor complications CONCLUSION: Irrigation and minimal debridement in the outpatient setting is an acceptable method of treatment for low energy gunshot wounds to the lower limbs, without orthopaedic or vascular involvement.

The prospective relation between dimensions of anxiety and the initiation of adolescent alcohol use.

Examined the relation between early anxiety symptomatology (generalized and separation) and initiation of alcohol use 4 years later in an epidemiological sample of 936 children (45% girls), assessed at ages 9, 11, and 13, while controlling for the effects of depression. Although earlier overall anxiety symptomatology was unrelated to later onset of drinking, children with early symptoms of generalized anxiety were found to be at increased risk for initiation of alcohol use, whereas children with early symptoms of separation anxiety were at decreased risk. The magnitude of these relations was equally strong for boys and girls. In addition, early depressive symptomatology was associated with increased risk for initiation of alcohol use in adolescence. Results indicate that it is important to consider specific dimensions of anxiety symptomatology when attempting to identify those individuals at risk for early initiation of alcohol use.

Specifying the relations between affect and heavy alcohol use among young adults.

Current reformulations of the tension reduction hypothesis posit that only a subset of vulnerable individuals are at risk for drinking in response to negative affect. To further specify this model, this study examined the types of mood and social contexts under which affect and alcohol use are associated. Participants were 74 college students who completed repeated assessments of mood, alcohol use, friendship quality, and social support. A complex pattern of findings supported the moderating influences of gender, friendship factors, and the timing of behavior (i.e., weekends vs. weekdays) on the relation between affect and alcohol use. Young adults with less intimate and supportive friendships, as compared with their peers, showed risk for greater drinking following relative elevations in sadness and hostility. Such drinking episodes, in turn, predicted subsequent elevations in these same negative moods the following week. Gender differences in such a cyclical pattern of affect and alcohol use were found to vary across differing emotional experiences. Recommendations for a more refined theory of affect and alcohol use are discussed.