The 3-D solar radioastronomy and the structure of the corona and the solar wind

The mechanism causing solar radio bursts (1 and 111) is examined. It is proposed that a nonthermal energy source is responsible for the bursts; nonthermal energy is converted into electromagnetic energy. The advantages are examined for an out-of-the-ecliptic solar probe mission, which is proposed as a means of stereoscopically viewing solar radio bursts, solar magnetic fields, coronal structure, and the solar wind

The rhizosphere: a playground and battlefield for soilborne pathogens and beneficial microorganisms

The rhizosphere is a hot spot of microbial interactions as exudates released by plant roots are a main food source for microorganisms and a driving force of their population density and activities. The rhizosphere harbors many organisms that have a neutral effect on the plant, but also attracts organisms that exert deleterious or beneficial effects on the plant. Microorganisms that adversely affect plant growth and health are the pathogenic fungi, oomycetes, bacteria and nematodes. Most of the soilborne pathogens are adapted to grow and survive in the bulk soil, but the rhizosphere is the playground and infection court where the pathogen establishes a parasitic relationship with the plant. The rhizosphere is also a battlefield where the complex rhizosphere community, both microflora and microfauna, interact with pathogens and influence the outcome of pathogen infection. A wide range of microorganisms are beneficial to the plant and include nitrogen-fixing bacteria, endo- and ectomycorrhizal fungi, and plant growth-promoting bacteria and fungi. This review focuses on the population dynamics and activity of soilborne pathogens and beneficial microorganisms. Specific attention is given to mechanisms involved in the tripartite interactions between beneficial microorganisms, pathogens and the plant. We also discuss how agricultural practices affect pathogen and antagonist populations and how these practices can be adopted to promote plant growth and health

Mathematical Tutorials in Introductory Physics

Students in introductory calculus-based physics not only have difficulty understanding the fundamental physical concepts, they often have difficulty relating those concepts to the mathematics they have learned in math courses. This produces a barrier to their robust use of concepts in complex problem solving. As a part of the Activity-Based Physics project, we are carrying out research on these difficulties and are developing instructional materials in the tutorial framework developed at the University of Washington by Lillian C. McDermott and her collaborators. In this paper, we present a discussion of student difficulties and the development of a mathematical tutorial on the subject of pulses moving on strings.Comment: 8 pages, 2 figures, 1 table, 12 references and note

Chapter 03: Impacts of climate change on the physical oceanography of the Great Barrier Reef

The oceans function as vast reservoirs of heat, the top three metres of the ocean alone stores all the equivalent heat energy contained within the atmosphere29. This is due to the high specific heat of water, which is a measure of the ability of matter to absorb heat. The ocean therefore has by far the largest heat capacity and hence energy retention capability of any other climate system component. Surface ocean currents (significantly forced by large scale winds) play a major role in redistributing the earth’s heat energy around the globe by transporting it from the tropical regions poleward principally via western boundary currents such as the East Australian Current (EAC). These currents therefore have a major affect on maritime and continental weather and climate.This is Chapter 3 of Climate change and the Great Barrier Reef: a vulnerability assessment. The entire book can be found at http://hdl.handle.net/11017/13

On the rational subset problem for groups

We use language theory to study the rational subset problem for groups and monoids. We show that the decidability of this problem is preserved under graph of groups constructions with finite edge groups. In particular, it passes through free products amalgamated over finite subgroups and HNN extensions with finite associated subgroups. We provide a simple proof of a result of Grunschlag showing that the decidability of this problem is a virtual property. We prove further that the problem is decidable for a direct product of a group G with a monoid M if and only if membership is uniformly decidable for G-automata subsets of M. It follows that a direct product of a free group with any abelian group or commutative monoid has decidable rational subset membership.Comment: 19 page

The case for TIPS: an examination of the costs and benefits

Slightly more than a decade has passed since the introduction of the Treasury Inflation-Protected Securities (TIPS) program, through which the U.S. Treasury Department issues inflation-indexed debt. Several studies have suggested that the program has been a financial disappointment for the Treasury and by extension U.S. taxpayers. Relying on ex post analysis, the studies argue that a more cost-effective strategy remains the issuance of nominal Treasury securities. This article proposes that evaluations of the TIPS program be more comprehensive, and instead focus on the ex ante costs of TIPS issuance compared with nominal Treasury issuance. The authors contend that ex ante analysis is a more effective way to assess the costs of TIPS over the long run. Furthermore, relative cost calculations--whether ex post or ex ante--are just one aspect of a comprehensive analysis of the costs and benefits of the TIPS program. TIPS issuance provides other benefits that should be taken into account when evaluating the program, especially when TIPS are only marginally more expensive or about as expensive to issue as nominal Treasury securities.Treasury bonds ; Debt

Hall Effect and Specific Resistance in Evaporated Films of Silver, Copper and Iron

Previous investigators have found the specific resistance a constant for metallic films, until the thickness becomes comparable with particle dimensions, at which thickness the resistance becomes very great. Wait found the resistivity of chemically deposited silver films, whose thicknesses were greater than the above mentioned critical thickness, to be only slightly greater than that of the bulk metal. He found the Hall Effect in these films, as well as in films whose thicknesses were less than the critical thickness, to be the same as that of bulk silver. On the conception that the substance in a film consists of granules not in the intimate contact obtaining in the bulk form, these results could be accounted for. Consequently it became desirable to investigate silver films obtained by an evaporation method, in order to ascertain how they differ from chemically deposited films, and how these differences affect their properties