4,683 research outputs found
Anticrossing of spin-split subbands in quasi-one-dimensional wires
In quantum Hall systems, both anticrossings and magnetic phase transitions can occur when opposite-spin Landau levels coincide. Our results indicate that both processes are also possible in quasi-1D quantum wires in an in-plane B field, B-parallel to. Crossings of opposite-spin 1D subbands resemble magnetic phase transitions at zero dc source-drain bias, but display anticrossings at high dc bias. Our data also imply that the well-known 0.7 structure may evolve into a spin-hybridized state in finite dc bias
Interaction effects at crossings of spin-polarized one-dimensional subbands
We report conductance measurements of ballistic one-dimensional (1D) wires defined in GaAs/AlGaAs heterostructures in an in-plane magnetic field, B. When the Zeeman energy is equal to the 1D subband energy spacing, the spin-split subband Nup arrow intersects (N+1)down arrow, where N is the index of the spin-degenerate 1D subband. At the crossing of N=1up arrow and N=2down arrow subbands, there is a spontaneous splitting giving rise to an additional conductance structure evolving from the 1.5(2e(2)/h) plateau. With further increase in B, the structure develops into a plateau and lowers to 2e(2)/h. With increasing temperature and magnetic field the structure shows characteristics of the 0.7 structure. Our results suggest that at low densities a spontaneous spin splitting occurs whenever two 1D subbands of opposite spins cross
Transatlantic Patterns of Risk Regulation: Implications for International Trade and Cooperation
This report presents a study commissioned by the European Parliament to compare regulatory standards in the EU and the US in four key sectors (food safety, automobiles, chemicals, and pharmaceuticals), chosen for their relevance both to consumer protection and transatlantic trade, and focusing on whether different approaches to risk regulation may lead to different levels of protection. How risks are regulated in the US and the EU can affect domestic outcomes (such as the benefits and costs of protecting consumers, health and environment), and can also foster or limit the opportunities for international trade
Patient Characteristics Affect Hip Contact Forces during Gait
Objective: To examine hip contact force (HCF), calculated through multibody modelling, in a large total hip replacement (THR) cohort stratified by patient characteristics such as BMI, age and function.
Design: 132 THR patients undertook one motion capture session of gait analysis at a self-selected walking speed. HCFs were then calculated using the AnyBody Modelling System. Patients were stratified into three BMI groups, five age groups, and finally three functional groups determined by their self-selected gait speed. Independent 1-dimensional linear regression analyses were performed to separately evaluate the influence of age, BMI and functionality on HCF, by means of statistical parametric mapping (SPM).
Results: The mean predicted HCF were comparable to HCFs measured with an instrumented prosthesis reported in the literature. The regression analyses revealed a statistically significant positive relationship between BMI and HCF, indicating that obese patients are more likely to experience higher HCF during most of the stance phase, while a statistically significant relationship with age was found only during the late swing-phase. Patients with higher functional ability exhibited significantly increased peak contact forces, while patients with lower functional ability displayed a pathological flattening of the typical double hump force profile.
Conclusions: HCFs experienced at the bearing surface are highly dependent on patient characteristics. BMI and functional ability were determined to have the biggest influence on contact force. Current preclinical testing standards do not reflect this
Diversity and the Civic Spirit in British Neighbourhoods: An Investigation with MCDS and EMBES 2010 Data
Recently, there has been a proliferation of studies investigating the relationship between diversity and outcomes such as social cohesion and civic mindedness. This article addresses several common problems in this field and, using data for British neighbourhoods, elaborates on the experiences of both white British and ethnic minority respondents. We conclude that, if anything, diversity should be encouraged to cement the integration progress of migrants and foster stronger identification with Britain in the second generation. Deprivation at the neighbourhood level along with individual factors such as fear of crime is a much stronger predictor of deterioration of the civic spirit than diversity. Bridging contacts have the expected strong positive association with cohesion outcomes; and contrary to policy concerns no strong negative impact is observed for associational bonding among minority ingroupers
How do field of view and resolution affect the information content of panoramic scenes for visual navigation? A computational investigation
The visual systems of animals have to provide information to guide behaviour and the informational requirements of an animal’s behavioural repertoire are often reflected in its sensory system. For insects, this is often evident in the optical array of the compound eye. One behaviour that insects share with many animals is the use of learnt visual information for navigation. As ants are expert visual navigators it may be that their vision is optimised for navigation. Here we take a computational approach in asking how the details of the optical array influence the informational content of scenes used in simple view matching strategies for orientation. We find that robust orientation is best achieved with low-resolution visual information and a large field of view, similar to the optical properties seen for many ant species. A lower resolution allows for a trade-off between specificity and generalisation for stored views. Additionally, our simulations show that orientation performance increases if different portions of the visual field are considered as discrete visual sensors, each giving an independent directional estimate. This suggests that ants might benefit by processing information from their two eyes independently
The influence of surgical approach on outcomes of total hip arthroplasty
The vast majority of total hip arthroplasties performed in the UK are undertaken using either a posterior or direct lateral approach. This review describes the functional outcomes of these approaches. Functional outcome can be assessed through motion capture of function, strength testing of muscle groups around the hip and imaging of anatomical structures. Regardless of surgical approach, total hip arthroplasty patients rarely return to the ‘normal’ gait exhibited by healthy age-matched controls. The direct lateral approach is associated with abductor deficiencies whilst the posterior approach may introduce extension and rotation deficits. How long functional differences persist between surgical approaches is unclear. The emergence of improved imaging technologies as well as isokinetic dynamometry (muscle strength testing) and 3D biomechanical modelling provide more comprehensive evaluations than traditional post-operative assessments such as radiology or couch examination. Targeted physiotherapy has been suggested as a possible intervention to counter lasting functional deficits. This review provides a foundation to inform surgeons of the impact of each approach to justify their surgical practice and may inform physical rehabilitation regimens post-surgery
Childhood tuberculosis: progress requires an advocacy strategy now
Childhood tuberculosis (TB) is a preventable and curable infectious disease that remains overlooked by public health authorities, health policy makers and TB control programmes. Childhood TB contributes significantly to the burden of disease and represents the failure to control transmission in the community. Furthermore, the pool of infected children constitutes a reservoir of infection for the future burden of TB. It is time to prioritise childhood TB, advocate for addressing the challenges and grasp the opportunities in its prevention and control. Herein, we propose a scientifically informed advocacy agenda developed at the International Childhood TB meeting held in Stockholm, Sweden, from March 17 to 18, 2011, which calls for a renewed effort to improve the situation for children affected by Mycobacterium tuberculosis exposure, infection or disease. The challenges and needs in childhood TB are universal and apply to all settings and must be addressed more effectively by all stakeholders
Graphene Oxide Bulk-Modified Screen-Printed Electrodes Provide Beneficial Electroanalytical Sensing Capabilities
We demonstrate a facile methodology for the mass production of graphene oxide (GO) bulk-modified screen-printed electrodes (GO-SPEs) that are economical, highly reproducible and provide analytically useful outputs. Through fabricating GO-SPEs with varying percentage mass incorporations (2.5%, 5%, 7.5% and 10%) of GO, an electrocatalytic effect towards the chosen electroanalytical probes is observed, which increases with greater GO incorporated compared to bare/graphite SPEs. The optimum mass ratio of 10% GO to 90% carbon ink produces an electroanalytical signal towards dopamine (DA) and uric acid (UA) which is ca. ×10 greater in magnitude than that achievable at a bare/unmodified graphite SPE. Furthermore, 10% GO-SPEs exhibit a competitively low limit of detection (3σ) towards DA at ca. 81 nM, which is superior to that of a bare/unmodified graphite SPE at ca. 780 nM. The improved analytical response is attributed to the large number of oxygenated species inhabiting the edge and defect sites of the GO nanosheets, which are able to exhibit electrocatalytic responses towards inner-sphere electrochemical analytes. Our reported methodology is simple, scalable, and cost effective for the fabrication of GO-SPEs that display highly competitive LODs and are of significant interest for use in commercial and medicinal applications
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