1,870 research outputs found
Influence of Foliar Exposure, Adjuvants, and Rain-free Period on the Efficacy of Glyphosate for Torpedograss Control
The proportion of torpedograss tissue exposed to glyphosate at application rates of 0.28, 0.56, 1.12, 2.24, and 4.48 kg/ha affected control as measured by regrowth. The effect of tissue exposure was more pronounced as application rate decreased. This study suggests that higher rates of glyphosate need to be used during higher water levels, when less torpedograss tissue is exposed to herbicide spray and lower rates may be used during periods of low water levels. Addition of the water conditioning agent Quest (R) (0.25% v/v) to glyphosate spray mixtures diminished the influence of simulated rain events following glyphosate application. Twelve other adjuvants did not influence the effect of simulated rain events
Cooling of the H Chondrite Parent Body: Examination and Assessment of 40Ar/39Ar Age Data
No abstract available
Lateral groove geometry for planar UV written evanescent devices - new flexibility new devices
Conventional evanescent optical devices have made use of etched windows to allow access of an optical field to a material of interest. Such devices are a route to accurate refractive index sensors and to realising modulators, however, the geometry of etching the cladding to give the fluid access to a pre-defined core waveguide mode is limiting. In this work, we present an alternative approach in which a groove is cut using a polishing saw blade to give a vertical, high optical quality trench. Optical waveguides are then UV written to allow evanescent lateral access of the mode to a fluid placed in the trench. This seemingly subtle change in geometry provides greatly increased flexibility to tailor the interaction between the optical mode and the surrounding material, by, for example, changing the mode size and the allowing couplers or tapers to be used
Northwest Africa 11522: A New Paired Stone of Martian Polymict Regolith Breccia Northwest Africa 7034
No abstract available
New geometry for planar UV written refractive index sensors
We shall present some of our recent results from our work on UV written planar waveguide refractive index sensors. Refractive index of an analyte is measured through the perturbation of an optical mode, interrogation of the modal index is achieved via the reflected spectra from a Bragg grating defined in the same process as the channel waveguide. Here we introduce a new geometry which embraces the benefits of planar technology to realise new integrated devices. The geometry allows several different sensors to be defined on the same substrate each offering complementary information. Such information may include index as a function of penetration depth for surface binding analytes, interrogation wavelength for dispersion analysis, enhanced sensitivity in specific index ranges and temperature compensation. We shall also outline the inherent fabrication advantages and device feature benefits, including a reduction in return loss, spectral artefacts and a suggested reduction in stress induced birefringence. The silica sensing surface opposed to gold used in SPR devices opens new avenues to exploit surface binding. With a marked reduction in complexity and cost these devices may have significant impact in future sensor markets
An update of stabilisation exercises for low back pain: a systematic review with meta-analysis
Background
Non-specific low back pain (NSLBP) is a large and costly problem. It has a lifetime prevalence of 80% and results in high levels of healthcare cost. It is a major cause for long term sickness amongst the workforce and is associated with high levels of fear avoidance and kinesiophobia. Stabilisation (or ‘core stability’) exercises have been suggested to reduce symptoms of pain and disability and form an effective treatment. Despite it being the most commonly used form of physiotherapy treatment within the UK there is a lack of positive evidence to support its use. The aims of this systematic review update is to investigate the effectiveness of stabilisation exercises for the treatment of NSLBP, and compare any effectiveness to other forms of exercise.
Methods
A systematic review published in 2008 was updated with a search of PubMed, CINAHL, AMED, Pedro and The Cochrane Library, October 2006 to October 2013. Two authors independently selected studies, and two authors independently extracted the data. Methodological quality was evaluated using the PEDro scale. Meta-analysis was carried out when appropriate.
Results
29 studies were included: 22 studies (n = 2,258) provided post treatment effect on pain and 24 studies (n = 2,359) provided post treatment effect on disability. Pain and disability scores were transformed to a 0 to 100 scale. Meta-analysis showed significant benefit for stabilisation exercises versus any alternative treatment or control for long term pain and disability with mean difference of -6.39 (95% CI -10.14 to -2.65) and -3.92 (95% CI -7.25 to -0.59) respectively. The difference between groups was clinically insignificant. When compared with alternative forms of exercise, there was no statistical or clinically significant difference. Mean difference for pain was -3.06 (95% CI -6.74 to 0.63) and disability -1.89 (95% CI -5.10 to 1.33).
Conclusion
There is strong evidence stabilisation exercises are not more effective than any other form of active exercise in the long term. The low levels of heterogeneity and large number of high methodological quality of available studies, at long term follow-up, strengthen our current findings, and further research is unlikely to considerably alter this conclusion
Porosity Variations Between Fine Grained Rims and Matrix in a CM Chondrite by 3D Serial Sectioning
No abstract available
Gouy phase compensation in quasi-phase matching
In any focussed nonlinear interaction the focus induced phase shift, known as the Gouy phase shift, provides an imperfection in phase matching for any linearly invariant material. However, using an appropriately designed quasi-phase matched structure it is theoretically possible to compensate for the deleterious effects of the Gouy phase shift, allowing a symmetric frequency response and tighter optimal focussing than in a uniform material
Flat-top temperature tuning response in periodically-poled nonlinear crystals
Second harmonic generation via periodically-poled nonlinear materials offers an efficient means of generating high-quality visible light that would be otherwise unattainable with traditional laser sources. While this technology has the potential for implementation in many mass-industrial applications, temperature stability requirements of 0.1 deg.C can make packaging with a pump source problematic. Using our high fidelity poling technique we have achieved precise placement of poled domains in Lithium Niobate based on the resulting mathematical models. These initial devices provide more than 4 deg.C flat-top temperature stability, albeit with a corresponding loss in operational efficiency. Our aim is to implement improved designs in magnesium-doped Lithium Niobate for packaging with near-room temperature diode-based pump sources, as could be applied towards RGB TV and projector applications
Evaluation of the effect of Bti on Simulium posticatum and other organisms in the River Stour, 1991
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