605 research outputs found
The Environmental Cooperation Agreement between Mexico and the United States: A Response to the Pollution Problems of the Borderlands
Determinant Attribute Analysis: A Tool for new Wood Product Development
Determinant attribute analysis was employed to identify the physical product characteristics most crucial in the purchase decision process for office furniture substrate materials. Fastener withdrawal strength, surface smoothness, flatness, stiffness (MOE), and edgebanding capability had the most effect on selection decisions. These results were then viewed in terms of the development of a new substrate product and the opportunities that could arise from achieving a superior competitive advantage based on those characteristics. The importance of recognizing customer needs in the new product development process is central to the analysis, and the potential of determinant attribute analysis as a powerful tool for this process is demonstrated
Mid-infrared quantum optics in silicon
Applied quantum optics stands to revolutionise many aspects of information
technology, provided performance can be maintained when scaled up. Silicon
quantum photonics satisfies the scaling requirements of miniaturisation and
manufacturability, but at 1.55 m it suffers from unacceptable linear and
nonlinear loss. Here we show that, by translating silicon quantum photonics to
the mid-infrared, a new quantum optics platform is created which can
simultaneously maximise manufacturability and miniaturisation, while minimising
loss. We demonstrate the necessary platform components: photon-pair generation,
single-photon detection, and high-visibility quantum interference, all at
wavelengths beyond 2 m. Across various regimes, we observe a maximum net
coincidence rate of 448 12 Hz, a coincidence-to-accidental ratio of 25.7
1.1, and, a net two photon quantum interference visibility of 0.993
0.017. Mid-infrared silicon quantum photonics will bring new quantum
applications within reach.Comment: 8 pages, 4 figures; revised figures, updated discussion in section 3,
typos corrected, added referenc
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Development of cytomegalovirus (CMV) immune recovery uveitis is associated with Th17 cell depletion and poor systemic CMV-specific T cell responses.
Backgroundthe immune reconstitution inflammatory syndromes (IRIS) are a spectrum of inflammatory conditions associated with opportunistic infections and occurring in approximately16% of human immunodeficiency type 1 (HIV-1)-infected patients given antiretroviral therapy. It has been proposed that these conditions are linked by a dysregulated immune system that is prone to exaggerated responses. However, immunologic studies have been limited by the availability of longitudinal samples from patients with IRIS and appropriate matched control subjects. Cytomegalovirus (CMV) immune recovery uveitis (IRU) is an IRIS occurring in up to 38% of patients with CMV retinitis. Although the pathologic immune responses occur in the eye, immune dysregulation that allows for development of pathologic responses is presumably caused by faulty systemic immune cell reconstitution.Methodswe examined CMV-specific T cell responses, regulatory T (T(reg)) cell function and polyclonal T cell responses, including IL-17 production, in 25 patients with CMV IRU and 49 immunorestored control subjects with CMV retinitis who did not develop IRU.Resultspatients with CMV IRU had poor CMV-specific CD4(+) T cell responses, as compared with control subjects, whereas CD8(+) T cell responses were comparable. Patients with CMV IRU were characterized by smaller numbers of circulating Th17 cells. Deficiency in anti-CMV responses was not associated with differences in T(reg) cell function.Conclusionsthe T(reg) cell compartment is intact in patients with CMV IRU, and these patients do not develop exaggerated systemic CMV-specific or polyclonal immune responses. Cases are instead characterized by more profound depletion of Th17 cells and poor antiviral immune responses. CMV IRU may be most likely to develop in persons experiencing the greatest degree of immune dysfunction before initiating highly active antiretroviral therapy
Effect of Time of Access to Pasture and the Provision of a Total Mixed Ration on the Performance and Methane Production of High Yielding Dairy Cows
Allowing cows to spend time on pasture may improve their welfare, although high yielding cows are unable to consume sufficient amounts of grass to maintain milk yield and require supplementation (Charlton et al. 2011). The inclusion of grass in the diet of high yielding cows may have benefits as grass contains polyunsaturated fatty acids which can reduce methane production (Martin et al. 2008). Additionally, the soluble carbohydrate content in grass is higher in the afternoon which may increase intake (Trevaskis et al. 2004). The aim of the experiment was to determine the effects of timing of pasture access and the provision of access to total mixed ration (TMR) when at grass on the performance and methane production of high yielding dairy cows
Feed Batch Mixer Box for Beef Cattle Farm
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Temperature dependence of the Kerr nonlinearity and two-photon absorption in a silicon waveguide at 1.55{\mu}m
We measure the temperature dependence of the two-photon absorption and
optical Kerr nonlinearity of a silicon waveguide over a range of temperatures
from 5.5 to 300 K at a wavelength of 1.55 {\mu}m. The two-photon absorption
coefficient is calculated from the power dependent transmission of a 4.9 ps
pulse. We observed a nearly two-fold decrease in the two-photon absorption
coefficient from 0.76 cm/GW at 300K to 0.42 cm/GW at 5.5 K. The Kerr
nonlinearity is inferred from the self-phase modulation induced spectral
broadening of the transmitted pulse. A smaller reduction in Kerr nonlinearity
from 5.2E-18 m^2/W at 300 K to 3.9E-18 m^2/W at 5.5 K is found. The increased
ratio of Kerr to absorptive nonlinearity at low temperatures indicates an
improved operation of devices that make use of a nonlinear phase shift, such as
optical switches or parametric photon-pair sources. We examine how the
heralding efficiency of a photon-pair source will change at low temperature. In
addition, the modelling and experimental techniques developed can readily be
extended to other wavelengths or materials of interest.Comment: 9 pages, 5 figure
Effect of applied field and rate of voltage rise on surface breakdown of oil-immersed polymers
In sub-systems of high-voltage, pulsed-power machines, the introduction of a solid into bulk liquid insulation located between two conductors is often necessary to provide mechanical support. Breakdown events on or around the surface of the solid can result in permanent damage to the insulation system. Described in the present paper are experimental results pertaining to surface breakdown of five different solid dielectrics held between plane-parallel electrodes immersed in mineral oil. The effect of varying level of peak applied field from 200 kV/cm (dV/dt 70 kV/µs) to 1 MV/cm (dV/dt 350 kV/µs) is investigated, and the breakdown voltages and times to breakdown are compared to those for an open oil gap. The time to breakdown is shown to be reduced by the introduction of a solid spacer into the gap. Rexolite and Torlon samples suffered significant mechanical damage, and consistently showed lower breakdown voltage than the other materials - average streamer propagation velocity up to 125 km/s was implied by the short times to breakdown. Although ultra-high molecular weight polyethylene yielded the longest times to breakdown of the five types of liquid-solid gap, breakdown events could be initiated at lower levels of applied field for spacers of this material than those with permittivity closely matched to that of the surrounding mineral oil. Polypropylene and low-density polyethylene are concluded to provide the most stable performance in mineral oil. Due to the similarity of the applied voltage wave-shape (1/6.5 µs) to short-tail lightning impulses, the results may also be of interest to high-voltage system designers in the power industry
Validation of a Measure of Alliance for an Adolescent Inpatient Setting
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/112270/1/cpp1901.pd
Managing idiopathic intracranial hypertension in pregnancy: practical advice
Idiopathic intracranial hypertension (IIH) is more common in women of reproductive age who have obesity, yet there is little information on its management specifically in pregnancy. Women with IIH should plan their pregnancy including discussing contraception before pregnancy, recognising that hormonal contraceptives are not contraindicated. Potentially teratogenic medications including acetazolamide and topiramate are not recommended during pregnancy or in those with immediate plans to conceive; prescribing acetazolamide in pregnancy must only follow discussion with the patient and their obstetrician. Ideally, patients should aim to achieve disease remission or control before pregnancy, through optimising their weight. Although weight gain is expected in pregnancy, excessive weight gain may exacerbate IIH and increase maternal and fetal complications; evidence-based recommendations for non-IIH pregnancies may help in guiding optimal gestational weight gain. The vast majority of women with IIH can have a normal vaginal delivery, with spinal or epidural anaesthesia if needed, provided the papilloedema is stable or the IIH is in remission
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