2,913 research outputs found
Assessment of effects on vegetation of degradation products from alternative fluorocarbons
Concern with the effects of fluorides on plants has been devoted to that resulting from dry deposition (mainly with reference to gaseous HF and secondarily with particulate forms). The occurrence of precipitation as rain or mist and the presence of dew or free water on the foliage has mainly been considered with respect to their effects on the accumulation of air-borne fluoride and not with fluoride in wet deposition. That is, precipitation has been viewed primarily with respect to its facilitation of the solution and subsequent absorption of deposits by the foliar tissues or its elution of deposited fluoride from foliage. Accordingly, our evaluation of inorganic fluoride from fluorocarbon degradation rests upon a comparison with what is known about the effects of industrial emissions and what could be considered the natural condition
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Contrasting arbuscular mycorrhizal communities colonizing different host plants show a similar response to a soil phosphorus concentration gradient
High soil phosphorus (P) concentration is frequently shown to reduce root colonization by arbuscular mycorrhizal (AM) fungi, but the influence of P on the diversity of colonizing AM fungi is uncertain.
We used terminal restriction fragment length polymorphism (T-RFLP) of 18S rDNA and cloning to assess diversity of AM fungi colonizing maize (Zea mays), soybean (Glycene max) and field violet (Viola arvensis) at three time points in one season along a P gradient of 10–280 mg l−1 in the field.
Percentage AM colonization changed between sampling time points but was not reduced by high soil P except in maize. There was no significant difference in AM diversity between sampling time points. Diversity was reduced at concentrations of P > 25 mg l−1, particularly in maize and soybean. Both cloning and T-RFLP indicated differences between AM communities in the different host species. Host species was more important than soil P in determining the AM community, except at the highest P concentration.
Our results show that the impact of soil P on the diversity of AM fungi colonizing plants was broadly similar, despite the fact that different plants contained different communities. However, subtle differences in the response of the AM community in each host were evident
FAA Safety Seminar (Open to the General Public)
This seminar will focus on reducing the aviation accident rate through the enhancement of safety culture. Human factors influences on accident and incidents will also be discussed with an emphasis on the prevention of future occurrences.
The keynote speaker is Robert Sumwalt, current member of the National Transportation Safety Board (NTSB). A pilot with more than 30 years of experience including 24 years as an airline pilot, Sumwalt was appointed to a two-year term with the NTSB as Vice Chairman in 2006 by President George W. Bush. He was then reappointed to the Board as a member for an additional five-year term by President Barack Obama in 2011. He has been involved with and led numerous airline safety programs and is co-founder of the Air Line Pilots Association (ALPA) Critical Incident Response Program, which provides guidance to airline personnel involved in traumatic incidents. For more information about Mr. Sumwalt, http://www.ntsb.gov/about/bio_sumwalt.html
Daniel McCune is currently the University Safety Officer for Embry-Riddle Aeronautical University. He is also the Chairman of the Safety committee for the University Aviation Association, and serves on several national Safety advisory committees. Mr. McCune retired from the United States Army after serving 27 years. Mr. McCune\u27s last flying position in the Army was a Citation Jet Captain at Dobbins Air Force Base. He has flown over 6500 accident free hours. He has flown a multitude of aircraft a few are: CE-560, King Air, Queen Air, C-182, UH-1 Helicopter
It all just clicked: a longitudinal perspective on transitions within University
This paper explores the transitions that a group of students, admitted from further education colleges as part of broader widening access initiative at a Scottish research–intensive university, made across the lifetime of their degrees. It investigates how they negotiate their learning careers beyond the first year, and how they (re)define their approaches to independent learning as they progress to the later years of their courses. Evidence is drawn from 20 students who were interviewed during each of their three or four years of study to provide a longitudinal account of their experiences of engagement and participation at the university. We draw attention to three ways in which the students made transitions across the course of their degrees: to increased knowledge of the conventions of academic writing; to enhanced critical skills; and to practical strategies to prioritise learning
History-sensitive versus future-sensitive approaches to security in distributed systems
We consider the use of aspect-oriented techniques as a flexible way to deal
with security policies in distributed systems. Recent work suggests to use
aspects for analysing the future behaviour of programs and to make access
control decisions based on this; this gives the flavour of dealing with
information flow rather than mere access control. We show in this paper that it
is beneficial to augment this approach with history-based components as is the
traditional approach in reference monitor-based approaches to mandatory access
control. Our developments are performed in an aspect-oriented coordination
language aiming to describe the Bell-LaPadula policy as elegantly as possible.
Furthermore, the resulting language has the capability of combining both
history- and future-sensitive policies, providing even more flexibility and
power.Comment: In Proceedings ICE 2010, arXiv:1010.530
Energy Conversion Research
Contains reports on three research projects.U. S. Air Force (Research and Technology Division) under Contract AF33(615)-3489 with the Air Force Aero Propulsion Laboratory, Wright-Patterson Air Force Base, Ohi
Experimental Transmission of Kaposi's Sarcoma–Associated Herpesvirus (Kshv/Hhv-8) to Scid-Hu Thy/Liv Mice
Kaposi's sarcoma–associated herpesvirus (KSHV/HHV-8) is a novel human lymphotropic herpesvirus linked to several human neoplasms. To date, no animal model for infection by this virus has been described. We have examined the susceptibility of C.B-17 scid/scid mice implanted with human fetal thymus and liver grafts (SCID-hu Thy/Liv mice) to KSHV infection. KSHV virions were inoculated directly into the implants, and viral DNA and mRNA production was assayed using real-time quantitative polymerase chain reaction. This revealed a biphasic infection, with an early phase of lytic replication accompanied and followed by sustained latency. Ultraviolet irradiation of the inoculum abolished all DNA- and mRNA-derived signals, and infection was inhibited by ganciclovir. Viral gene expression was most abundant in CD19+ B lymphocytes, suggesting that this model faithfully mimics the natural tropism of this virus. Short-term coinfection with HIV-1 did not alter the course of KSHV replication, nor did KSHV alter levels of HIV-1 p24 during the acute phase of the infection. Although no disease was evident in infected animals, SCID-hu Thy/Liv mice should allow the detailed study of KSHV tropism, latency, and drug susceptibility
What's the Matter with Kansas?: The Development and Confirmation of the Evolutionary Attitudes and Literacy Survey (EALS)
This is the publisher's version, also available electronically from http://link.springer.com/article/10.1007%2Fs12052-010-0294-1.The present survey was designed to assess predominant regional belief systems and the roles these beliefs play in science understanding and attitudes, and curricular effectiveness in colleges and universities. To this end, we created a wide variety of theory-driven subscales (lower order factors) reflecting, for example, exposure to evolutionary material, young earth creationist beliefs, moral and social objections, political ideology, endorsement of intelligent design fallacies, knowledge (and distrust) of the scientific enterprise, and attitudes of evolutionary theory’s relevance in several domains (e.g., sciences and humanities). We also included potentially important demographic variables (e.g., rural upbringing, family size). Finally, we assessed openness to experience, a key facet of personality. Hierarchical Structural Equation Modeling (SEM) analysis showed the 16 constructs to have a theoretically meaningful and quantitatively coherent higher order factor structure. In this large Kansas sample of university students, creationist reasoning and conservative orientation (political and religious) were negatively associated with exposure to evolutionary theory, knowledge about it, and positive attitudes toward its relevance. At the same time, exposure to the theory was positively associated with knowledge and positive attitudes. Importantly, though most Kansas-specific demographic variables (e.g., rural origins) were largely unrelated to outcomes of interest in this university-based sample, the personality factor openness to experience appears to be highly relevant for several higher order factors (e.g., exposure, knowledge and relevance, and creationist reasoning). We close with implications for educators and the next steps in survey development
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