Radiation studies of optical and electronic components used in astronomical satellite studies

The synchronous orbit of the IUE carries the satellite through Earth's outer electron belt. A 40 mCi Sr90 source was used to simulate these electrons. A 5 mCi source of Co60 was used to simulate bremmstrahlung. A 10 MeV electron Linac and a 1.7 MeV electron Van de Graaf wer used to investigate the energy dependence of radiation effects and to perform radiations at a high flux rate. A 100 MeV proton cyclotron was used to simulate cosmic rays. Results are presented for three instrument systems of the IUE and measurements for specific components are reported. The three instrument systems were the ultraviolet converter, the fine error sensor (FES), and the SEC vidicon camera tube. The components were optical glasses, electronic components, silicon photodiodes, and UV window materials

Principles of Force Gradation in Skeletal Muscles

A brief survey is given of how motoneurons and motor units are used for the gradation Of muscle force during motor behavior. Basic properties of motoneurons and muscle fibers, including major kinds of functional specialization along the axis of ‘fast’ vs. ‘slow’, are reviewed. The principles underlying the rate and recruitment gradation of force are described, stressing that the properties of motoneurons and muscle fibers are matched to automate important aspects of the gradation procedure. Recent investigations concerning synaptically evoked changes in the discharge properties of motoneurons receive special attention, including ‘plateau’ currents and, under appropriate conditions, self-sustained ‘plateau’ discharges

Why President Trump may threaten vetoes on spending bills to promote his policy agenda

Though Donald Trump will enter the White House facing both a Republican controlled House and Senate, Congress is unlikely to be a rubber stamp on his legislative agenda. Traditionally, presidents use the threat of legislative veto to move policy closer to their own preferences, but these threats tend to not be credible. In new research, Hans Hassell and Sam Kernell look closely at one type of veto threat – those made to resist extra legislation and spending on annual spending bills. He finds that such threats to veto riders can influence legislation by encouraging bipartisanship in the legislative process, especially in the Senate

Presidents’ Vetoes and Audience Costs

Veto threats may offer presidents bargaining leverage, but such leverage will be diminished if they and those with whom they transact business view a veto as hurting the president’s approval rating and his party’s prospects in the next election. How concerned must presidents be about the audience costs associated with a veto? Political science research suggests that they should be in that the public does not like vetoes and punishes presidents when they exercise this authority. In this article we test this argument with survey responses during times after presidents have issued a veto threat but before an actual veto. While on average, respondents register opposition to a veto, this preference varies greatly with the specific policy in question and with respondents’ party identification and presidential approval. The results suggest that opposition to a veto comes disproportionately, may be limited to politically distant respondents, and thus may not be as costly as the net negative numbers suggest

Love Me In The Spring

https://digitalcommons.library.umaine.edu/mmb-vp/3992/thumbnail.jp

Good for Nothin\u27 But Love

Photo illustrations of two women in costume, seated on a table against a red background.https://scholarsjunction.msstate.edu/cht-sheet-music/2890/thumbnail.jp

Radiation effects induced in pin photodiodes by 40- and 85-MeV protons

PIN photodiodes were bombarded with 40- and 85-MeV protons to a fluence of 1.5 x 10 to the 11th power p/sq cm, and the resulting change in spectral response in the near infrared was determined. The photocurrent, dark current and pulse amplitude were measured as a function of proton fluence. Changes in these three measured properties are discussed in terms of changes in the diode's spectral response, minority carrier diffusion length and depletion width. A simple model of induced radiation effects is presented which is in good agreement with the experimental results. The model assumes that incident protons produce charged defects within the depletion region simulating donor type impurities

Risk of diabetic retinopathy at first screen in children at 12 and 13 years of age

AIMS: \ud \ud To investigate the relationships between age at diagnosis of diabetes, age at diabetic eye screening and severity of diabetic retinopathy at first and subsequent screenings in children aged 12 or 13 years.\ud \ud METHODS: \ud \ud Data were extracted from four English screening programmes and from the Scottish, Welsh and Northern Irish programmes on all children with diabetes invited for their first and subsequent screening episodes from the age of 12 years. Retinopathy levels at first and subsequent screens, time from diagnosis of diabetes to first screening and age at diagnosis in years were calculated.\ud \ud RESULTS: \ud \ud Data were available for 2125 children with diabetes screened for the first time at age 12 or 13 years. In those diagnosed with diabetes at 2 years of age or less, the proportion with retinopathy in one or both eyes was 20% and 11%, respectively, decreasing to 8% and 2% in those diagnosed between 2 and 12 years (P < 0.0001). Only three children (aged 8, 10 and 11 years at diagnosis of diabetes) had images graded with referable retinopathy and, of these, two had non-referable diabetic retinopathy at all subsequent screenings. Of 1703 children with subsequent images, 25 were graded with referable diabetic retinopathy over a mean follow-up of 3.1 years, an incidence rate of 4.7 (95% confidence interval, 3.1-7.0) per 1000 per year.\ud \ud CONCLUSIONS: \ud \ud In this large cohort of children, the low prevalence and incidence rates of referable diabetic retinopathy suggest that screening earlier than age 12 is not necessary