Optical implementation of systolic array processing

Algorithms for matrix vector multiplication are implemented using acousto-optic cells for multiplication and input data transfer and using charge coupled devices detector arrays for accumulation and output of the results. No two dimensional matrix mask is required; matrix changes are implemented electronically. A system for multiplying a 50 component nonnegative real vector by a 50 by 50 nonnegative real matrix is described. Modifications for bipolar real and complex valued processing are possible, as are extensions to matrix-matrix multiplication and multiplication of a vector by multiple matrices

A method for the estimation of p-mode parameters from averaged solar oscillation power spectra

A new fitting methodology is presented which is equally well suited for the estimation of low-, medium-, and high-degree mode parameters from $m$-averaged solar oscillation power spectra of widely differing spectral resolution. This method, which we call the "Windowed, MuLTiple-Peak, averaged spectrum", or WMLTP Method, constructs a theoretical profile by convolving the weighted sum of the profiles of the modes appearing in the fitting box with the power spectrum of the window function of the observing run using weights from a leakage matrix that takes into account both observational and physical effects, such as the distortion of modes by solar latitudinal differential rotation. We demonstrate that the WMLTP Method makes substantial improvements in the inferences of the properties of the solar oscillations in comparison with a previous method that employed a single profile to represent each spectral peak. We also present an inversion for the internal solar structure which is based upon 6,366 modes that we have computed using the WMLTP method on the 66-day long 2010 SOHO/MDI Dynamics Run. To improve both the numerical stability and reliability of the inversion we developed a new procedure for the identification and correction of outliers in a frequency data set. We present evidence for a pronounced departure of the sound speed in the outer half of the solar convection zone and in the subsurface shear layer from the radial sound speed profile contained in Model~S of Christensen-Dalsgaard and his collaborators that existed in the rising phase of Solar Cycle~24 during mid-2010

The five-minute oscillations: What's left to be done

Current observational methods for studying these oscillations at large horizontal wavenumbers are discussed in detail and several two dimensional power spectra obtained with a CID camera on the main spectrograph of the McMath telescope at Kitt Peak National Observatory are described. The best-resolved observations of the p-mode obtained at chromospheric elevations are also presented. Recent progress in studies of the p-modes at low wavenumbers with full-disk velocity detection schemes is summarized. These full-disk observations of radial and low-degree non-radial modes were shown to place severe constraints on the theoretical calculation of solar interior structure. Progress in making fully-consistent solar models which fit both the high- and low-wave number observations is described. Finally, the observational and theoretical improvements that are necessary for further progress in solar seismology are summarized

Electroencephalographic baselines in astronaut candidates estimated by computation and pattern recognition techniques

Electroencephalographic baselines in astronaut candidates estimated by computer and pattern recognition technique

Underperforming policy networks : the biopesticides network in the United Kingdom

Loosely integrated and incomplete policy networks have been neglected in the literature. They are important to consider in terms of understanding network underperformance. The effective delivery and formulation of policy requires networks that are not incomplete or underperforming. The biopesticides policy network in the United Kingdom is considered and its components identified with an emphasis on the lack of integration of retailers and environmental groups. The nature of the network constrains the actions of its agents and frustrates the achievement of policy goals. A study of this relatively immature policy network also allows for a focus on network formation. The state, via an external central government department, has been a key factor in the development of the network. Therefore, it is important to incorporate such factors more systematically into understandings of network formation. Feedback efforts from policy have increased interactions between productionist actors but the sphere of consumption remains insufficiently articulated

Mechanical Properties of Stainless Steel Lipped Channels

This paper describes and discusses the results obtained from a series of tensile tests performed on cold formed stainless steel Type 304 members of lipped channel cross-section. Standard tensile tests on coupons cut from the webs of the sections were carried out, as were full section tensile tests. Ramberg-Osgood type curves based on the procedure suggested in the ASCE design code were fitted to the stress-strain results and these are compared with the experimental results and Ramberg-Osgood type curves derived on an alternative basis

Compressional Behaviour of Stainless Steel Short Struts

The effects of cold forming on both carbon steel and stainless steel structural members has been the subject of extensive research since the early 1940\u27s. Design code specifications for carbon steel members have been published in many countries around the world, including BS 5950, Part 5 in the UK (1) the AlSI Specification in the USA (2), and the new Eurocode 3, Part 1.3 (3). For stainless steel members there are fewer design code specifications available, and those that are available, which include the ANSI/ASCE in the USA (4) and the new Eurocode 3, Part 1.4 (5), do not give such detailed design recommendations as the carbon steel specifications. This paper describes the results obtained from a series of axial compression tests performed on short strut members of plain channel cross section cold formed from Type 304 stainless steel sheet. The comer radius and the material thickness are varied to examine the effects of cold forming on the load capacity of the channels in compression and the results are compared to those obtained from the relevant design specifications. Conclusions are drawn on the basis of the comparisons

"Don't think I'm going to leave you over it": Accounts of changing hepatitis C status among couples who inject drugs.

While the health-related benefits of intimate partnership are well documented, little attention has been paid to couples exposed to high levels of social stigma and exclusion. In this project we investigated an important site of stigma for partnerships by collecting accounts of changing hepatitis C (HCV) status ("sero-change") among couples that inject drugs. We explored what these accounts reveal about the meaning of HCV for these couples, and how this understanding contributes to our collective efforts at prevention and care. Drawing from a large dataset of qualitative interviews with couples, we focussed on those containing reports of sero-change. By adopting a methodology that positioned partnerships rather than individuals as the primary unit of analysis, we addressed the commonplace tendency to either overlook or discount as dysfunctional, the sexual relationships of people who inject drugs. While some couples sought greater biomedical understanding as a means of coming to terms with sero-change, others drew on alternative logics or "rationalities" that sat firmly outside conventional biomedical discourse (privileging notions of kinship, for example). Regardless of which explanatory framework they drew on, participants ultimately prioritised the security of their relationship over the dangers of viral infection. Effectively engaging couples in HCV prevention and care requires acknowledging and working with the competing priorities and complex realities of such partnerships beyond simply the identification of viral risk. The "new era" of direct acting antiviral treatments will provide ongoing opportunities to learn to integrate biomedical information within more socially sophisticated, relationally aware approaches

Hepatitis C prevention education needs to be grounded in social relationships

Most hepatitis C transmission occurs through the sharing of equipment used for injecting drugs, and in many settings, the majority of equipment sharing occurs between sexual partners. Despite this, few health promotion materials directly address sexual partnerships, couples or social relationships in general. This blindspot is one example of the ways in which prevention education in the area of drug use would benefit from careful rethinking. Focusing on the case of Australia, we argue that hepatitis C prevention education insufficiently acknowledges or mobilize social relationships, social dynamics and social contexts in its efforts to prevent hepatitis C transmission. This can lead it to reproduce the conditions for the very problems it seeks to solve. We further argue that hepatitis C prevention education is insufficiently attentive to its own social location, drawing too little on stakeholder expertise. Its effectiveness relies upon its social context, including the collaborative input and engagement of affected communities and other stakeholders. Better recognizing this would produce a stronger foundation for developing prevention strategies. As we conclude, this social foundation for hepatitis C prevention could be articulated into national, collaboratively developed guidelines on effective communication in hepatitis C and injecting drug use risk

Calibration of colour gradient bias in shear measurement using HST/CANDELS data

Accurate shape measurements are essential to infer cosmological parameters from large area weak gravitational lensing studies. The compact diffraction-limited point-spread function (PSF) in space-based observations is greatly beneficial, but its chromaticity for a broad band observation can lead to new subtle effects that could hitherto be ignored: the PSF of a galaxy is no longer uniquely defined and spatial variations in the colours of galaxies result in biases in the inferred lensing signal. Taking Euclid as a reference, we show that this colourgradient bias (CG bias) can be quantified with high accuracy using available multi-colour Hubble Space Telescope (HST) data. In particular we study how noise in the HST observations might impact such measurements and find this to be negligible. We determine the CG bias using HST observations in the F606W and F814W filters and observe a correlation with the colour, in line with expectations, whereas the dependence with redshift is weak. The biases for individual galaxies are generally well below 1%, which may be reduced further using morphological information from the Euclid data. Our results demonstrate that CG bias should not be ignored, but it is possible to determine its amplitude with sufficient precision, so that it will not significantly bias the weak lensing measurements using Euclid data