A Study of the Biology of \u3ci\u3eRhopalosiphum Padi\u3c/i\u3e (Homoptera: Aphididae) in Winter Wheat in Northwestern Indiana

Periodic collections of the bird cherry-oat aphid, Rhopalosiphum padi, during two years revealed small populations on winter wheat in Lafayette, Indiana. The greatest numbers were found on volunteer wheat plants before planting. In the autumn, aphids were detected on one-shoot plants by mid-October and also early March. The populations remained small until mid-June. We conclude that the aphid feeding did not significantly affect the plants, but helped spread barley yellow dwarf virus

Metal etching composition

The present invention is directed to a chemical etching composition for etching metals or metallic alloys. The composition includes a solution of hydrochloric acid, phosphoric acid, ethylene glycol, and an oxidizing agent. The etching composition is particularly useful for etching metal surfaces in preparation for subsequent fluorescent penetrant inspection

The preparation and evaluation of high-purity, fine-grained tungsten and tungsten alloy castings summary report

High purity, cylindrical castings of high melting point materials such as tungsten and tungsten alloy

Two systems developed for purifying inert atmospheres

Two systems, one for helium and one for argon, are used for purifying inert atmospheres. The helium system uses an activated charcoal bed at liquid nitrogen temperature to remove oxygen and nitrogen. The argon system uses heated titanium sponge to remove nitrogen and copper wool beds to remove oxygen. Both use molecular sieves to remove water vapor

Network growth models and genetic regulatory networks

We study a class of growth algorithms for directed graphs that are candidate models for the evolution of genetic regulatory networks. The algorithms involve partial duplication of nodes and their links, together with innovation of new links, allowing for the possibility that input and output links from a newly created node may have different probabilities of survival. We find some counterintuitive trends as parameters are varied, including the broadening of indegree distribution when the probability for retaining input links is decreased. We also find that both the scaling of transcription factors with genome size and the measured degree distributions for genes in yeast can be reproduced by the growth algorithm if and only if a special seed is used to initiate the process.Comment: 8 pages with 7 eps figures; uses revtex4. Added references, cleaner figure

Implementation of CIPP Model for Quality Evaluation at Zawia University

The limited English language skills among Libyan learners threatens their ability to interact with the international environment. Therefore, improvement in the provision of foreign language programmes is imperative, and can be carried out using different methods such as evaluation to critically examine a programme in order to improve its effectiveness. This study aims to evaluate the current English language teaching (ELT) provision provided by the English department in the faculties of education at Zawia University in Libya. It seeks to establish whether the current English language programme has ever been validated or updated. Moreover, this study will design a framework that will enhance the quality of the English language provision at Zawia University by indicating the strengths and weaknesses of the current English language programme. This study employed both quantitative and qualitative methods to collect the data, which were gathered through a questionnaire and semi-structured interviews. The evaluation of the current English as a foreign language programme at Zawia University revealed a number of inadequacies in terms of programme delivery, teaching resources, the balance of language skills taught and students work assessmen

History education, national identity, and the road to brexit

On June 23, 2016, citizens of the United Kingdom voted to exit from the European Union, a move commonly referred to as “Brexit.” The result of the referendum sent shock waves through the nation and had an immediate impact on the international economic and political landscape. Various analysts have suggested a host of reasons for the British public’s decision to leave the European Union, such as general dissatisfaction with falling wages and a declining standard of living, increased political mistrust, widespread concerns over rising levels of immigration, and growing anxiety over a perceived loss of national sovereignty. Notwithstanding these important factors, during the extensive, passionate, and fiercely contested debates that preceded and followed the referendum, it was strikingly evident that issues of national identity were of critical importance. Of significance, during the days leading up to the vote, two of Britain’s most widely read newspapers typically splashed their entire front covers with the British flag and unapologetically used emotive headlines to appeal to nationalist and patriotic sentiment. For example, one urged its readers to “BeLEAVE in Britain” (“We urge our readers,” 2016, June 14) and the other exclaimed on the day of voting: “Your Country Needs You: Vote Leave Today” (2016, June 23). Perhaps not surprisingly, the day after the referendum, one BBC reporter remarked, “What appears clear from the campaign is that the vote to leave was as much a statement about the country’s national identity, and all that involves, as it was about its economic and political future” (Eight reasons Leave won, 2016, June 24)

Systematic derivation of a surface polarization model for planar perovskite solar cells

Increasing evidence suggests that the presence of mobile ions in perovskite solar cells can cause a current-voltage curve hysteresis. Steady state and transient current-voltage characteristics of a planar metal halide CH$_3$NH$_3$PbI$_3$ perovskite solar cell are analysed with a drift-diffusion model that accounts for both charge transport and ion vacancy motion. The high ion vacancy density within the perovskite layer gives rise to narrow Debye layers (typical width $\sim$2nm), adjacent to the interfaces with the transport layers, over which large drops in the electric potential occur and in which significant charge is stored. Large disparities between (I) the width of the Debye layers and that of the perovskite layer ($\sim$600nm) and (II) the ion vacancy density and the charge carrier densities motivate an asymptotic approach to solving the model, while the stiffness of the equations renders standard solution methods unreliable. We derive a simplified surface polarisation model in which the slow ion dynamic are replaced by interfacial (nonlinear) capacitances at the perovskite interfaces. Favourable comparison is made between the results of the asymptotic approach and numerical solutions for a realistic cell over a wide range of operating conditions of practical interest.Comment: 32 pages, 7 figure

Prompt energization of relativistic and highly relativistic electrons during a substorm interval: Van Allen Probes observations

Abstract On 17 March 2013, a large magnetic storm significantly depleted the multi-MeV radiation belt. We present multi-instrument observations from the Van Allen Probes spacecraft Radiation Belt Storm Probe A and Radiation Belt Storm Probe B at ~6 Re in the midnight sector magnetosphere and from ground-based ionospheric sensors during a substorm dipolarization followed by rapid reenergization of multi-MeV electrons. A 50% increase in magnetic field magnitude occurred simultaneously with dramatic increases in 100 keV electron fluxes and a 100 times increase in VLF wave intensity. The 100 keV electrons and intense VLF waves provide a seed population and energy source for subsequent radiation belt enhancements. Highly relativistic (\u3e2 MeV) electron fluxes increased immediately at L* ~ 4.5 and 4.5 MeV flux increased \u3e90 times at L* = 4 over 5 h. Although plasmasphere expansion brings the enhanced radiation belt multi-MeV fluxes inside the plasmasphere several hours postsubstorm, we localize their prompt reenergization during the event to regions outside the plasmasphere. Key Points Substorm dynamics are important for highly relativistic electron energization Cold plasma preconditioning is significant for rapid relativistic energization Relativistic / highly relativistic electron energization can occur in \u3c 5 hrs