Arteriography of Cerebrovascular Disease

The importance of complete angiographic studies in patients suspected of extracranial vascular disease has been emphasized. Examples of a variety of lesions of the intracranial and extracranial circulation have been shown. It is important that the angiographer obtain adequate visualization of the circulation cephalad to the aortic arch with awareness of the type of lesion and technical problems that may be encountered. It is only in this way that further understanding of the stroke syndrome can be attained with appropriate therapy

The Proteases of Plants

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Advances in Neuroradiology

The development of two new radiological techniques has significantly enhanced the performance of neuroradiological diagnostic procedures. The first of these was installed as the prototype unit at the Medical College of Virginia in November of 1972 and has marked advantages for the performance of encephalography, angiography, and air myelography. The present communication will relate the experiences of the author during the initial 15 months of clinical evaluation. The second technique is an entirely new concept of obtaining further information from the data provided by the penetration of x-ray photons. Each of these units will be discussed briefly with an outline of the principle indications and advantage of each system

Versatile spectral imaging with an algorithm-based spectrometer using highly tuneable quantum dot infrared photodetectors

We report on the implementation of an algorithm-based spectrometer capable of reconstructing the spectral shape of materials in the mid-wave infrared (MWIR) and long-wave infrared (LWIR) wavelengths using only experimental photocurrent measurements from quantum dot infrared photodetectors (QDIPs). The theory and implementation of the algorithm will be described, followed by an investigation into this algorithmic spectrometer's performance. Compared to the QDIPs utilized in an earlier implementation, the ones used here have highly varying spectral shapes and four spectral peaks across the MWIR and LWIR wavelengths. It has been found that the spectrometer is capable of reconstructing broad spectral features of a range of bandpass infrared filters between wavelengths of 4 and 12 mu m as well as identifying absorption features as narrow as 0.3 mu m in the IR spectrum of a polyethylene sheet

The Effect of the Form of Tax Incentives on Individuals’ Savings Decisions

Congress and the media have both expressed concerns about Americans’ low savings rates. We address these concerns by investigating the extent to which the form of an investment’s tax preference affects individuals’ willingness to choose a tax-preferred vehicle over a less restrictive, but non-tax-preferred, investment. Specifically, we tested the extent to which subjects chose a traditional savings plan versus an investment resembling either a traditional IRA, Roth IRA, or government matching program. We find that subjects are not as sensitive to the form of the tax preference as they are to restrictions on their ability to withdraw funds. This suggests that, by reconsidering the extent to which individuals are forced to trade off tax savings and liquidity restrictions, Congress might more effectively promote individuals’ retirement savings

Accountable: Exploring the Inadequacies of Transparent Financial Practice in the Non-Profit Sector

Increasingly, governments and organisations publish data on expenditure and finance as 'open' data in order to be more transparent to the public in how funding is spent. Accountable is a web-based tool that visualises and relates open financial data provided by local government and non-profit organisations (NPOs) in the UK. A qualitative study was conducted where Accountable was treated as a technology probe, and used by representatives of NPOs and members of the public who invest their time or effort voluntarily into such organisations. The study highlighted how: current open data sets provided by public bodies are inadequate in their representation of funding structures; the focus on finance and fiscal expenditure in such data makes invisible the in-kind effort of volunteers and the wider beneficiaries of an organisation's work; and problems arising from the interoperability of open data technologies. The paper concludes with implications for the design of future systems, considering the domains of transparency and accountability in relation to the findings

Journal Staff

The aluminum–zinc-vacancy (Al Zn −V Zn ) complex is identified as one of the dominant defects in Al-containing n -type ZnO after electron irradiation at room temperature with energies above 0.8 MeV. The complex is energetically favorable over the isolated V Zn , binding more than 90% of the stable V Zn ’s generated by the irradiation. It acts as a deep acceptor with the (0/− ) energy level located at approximately 1 eV above the valence band. Such a complex is concluded to be a defect of crucial and general importance that limits the n -type doping efficiency by complex formation with donors, thereby literally removing the donors, as well as by charge compensation

Ab initio data-analytics study of carbon-dioxide activation on semiconductor oxide surfaces

The excessive emissions of carbon dioxide (CO2) into the atmosphere threaten to shift the CO2 cycle planet-wide and induce unpredictable climate changes. Using artificial intelligence (AI) trained on high-throughput first principles based data for a broad family of oxides, we develop a strategy for a rational design of catalytic materials for converting CO2 to fuels and other useful chemicals. We demonstrate that an electron transfer to the π-antibonding orbital of the adsorbed molecule and the associated bending of the initially linear molecule, previously proposed as the indicator of activation, are insufficient to account for the good catalytic performance of experimentally characterized oxide surfaces. Instead, our AI model identifies the common feature of these surfaces in the binding of a molecular O atom to a surface cation, which results in a strong elongation and therefore weakening of one molecular C-O bond. This finding suggests using the C-O bond elongation as an indicator of CO2 activation. Based on these findings, we propose a set of new promising oxide-based catalysts for CO2 conversion, and a recipe to find more