The role played by thermal feedback in heated Farley-Buneman waves at high latitudes

International audienceIt is becoming increasingly clear that electron thermal effects have to be taken into account when dealing with the theory of ionospheric instabilities in the high-latitude ionosphere. Unfortunately, the mathematical complexity often hides the physical processes at work. We follow the limiting cases of a complex but systematic generalized fluid approach to get to the heart of the thermal processes that affect the stability of E region waves during electron heating events. We try to show as simply as possible under what conditions thermal effects contribute to the destabilization of strongly field-aligned (zero aspect angle) Farley-Buneman modes. We show that destabilization can arise from a combination of (1) a reduction in pressure gradients associated with temperature fluctuations that are out of phase with density fluctuations, and (2) thermal diffusion, which takes the electrons from regions of enhanced temperatures to regions of negative temperature fluctuations, and therefore enhanced densities. However, we also show that, contrary to what has been suggested in the past, for modes excited along the E0×B direction thermal feedback decreases the growth rate and raises the threshold speed of the Farley-Buneman instability. The increase in threshold speed appears to be important enough to explain the generation of `Type IV' waves in the high-latitude ionosphere

Book Review: The Georgian Star: How William and Caroline Herschel Revolutionized Our Understanding of the Cosmos, Michael D. Lemonick

Book Review: The Georgian Star: How William and Caroline Herschel Revolutionized Our Understanding of the Cosmos, Michael D. Lemonick. New York, NY: W. W. Norton & Company (2009).The Meteoritics & Planetary Science archives are made available by the Meteoritical Society and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

The role played by thermal feedback in heated Farley-Buneman waves at high latitudes

It is becoming increasingly clear that electron thermal effects have to be taken into account when dealing with the theory of ionospheric instabilities in the high-latitude ionosphere. Unfortunately, the mathematical complexity often hides the physical processes at work. We follow the limiting cases of a complex but systematic generalized fluid approach to get to the heart of the thermal processes that affect the stability of E region waves during electron heating events. We try to show as simply as possible under what conditions thermal effects contribute to the destabilization of strongly field-aligned (zero aspect angle) Farley-Buneman modes. We show that destabilization can arise from a combination of (1) a reduction in pressure gradients associated with temperature fluctuations that are out of phase with density fluctuations, and (2) thermal diffusion, which takes the electrons from regions of enhanced temperatures to regions of negative temperature fluctuations, and therefore enhanced densities. However, we also show that, contrary to what has been suggested in the past, for modes excited along the E0×B direction thermal feedback decreases the growth rate and raises the threshold speed of the Farley-Buneman instability. The increase in threshold speed appears to be important enough to explain the generation of `Type IV' waves in the high-latitude ionosphere.Key words: Ionosphere (auroral ionosphere; iono- spheric irregularities; plasma waves and instabilities

The role played by thermal feedback in heated Farley-Buneman

waves at high latitude

The EU and controlling the use of the death penalty: an organising principle for which fundamental norm?

The abolition of the death penalty has been an important foreign policy objective of the European Union for over a decade and it claims to be ‘the leading institutional actor in the fight against the death penalty worldwide’ (EEAS, 2013: 2). The EU has played a prominent role in efforts since 2008 to pass resolutions in the United Nations General Assembly Third Committee calling for a moratorium on the use of the death penalty. This chapter examines the contestation that has taken place regarding controlling the use of the death penalty, and whether it is an organising principle of the fundamental norm of the right to life or alternatively, non-intervention in the domestic affairs of sovereign states. Following the common framework of the book, the chapter identifies four modes of contestation used by retentionist and abolitionist states alike and establishes when and where (either the UNGA or Human Rights Council) they are used to support each sides’ claims that controlling the use of the death penalty is a type-2 norm for their respective type-1 fundamental norms. The chapter concludes that the majority position—that it is an organising principle associated with the right to life—is pervasive, thus reflecting the EU’s preferred normative stance. However, in recent years, an acknowledgement that non-intervention cannot be ignored has become more pronounced

Clinical Interpretation of Urine Drug Tests: What Clinicians Need to Know About Urine Drug Screens

Urine drug testing is frequently used in clinical, employment, educational, and legal settings and misinterpretation of test results can result in significant adverse consequences for the individual who is being tested. Advances in drug testing technology combined with a rise in the number of novel misused substances present challenges to clinicians to appropriately interpret urine drug test results. Authors searched PubMed and Google Scholar to identify published literature written in English between 1946 and 2016, using urine drug test, screen, false-positive, false-negative, abuse, and individual drugs of abuse as key words. Cited references were also used to identify the relevant literature. In this report, we review technical information related to detection methods of urine drug tests that are commonly used and provide an overview of false-positive/false-negative data for commonly misused substances in the following categories: cannabinoids, central nervous system (CNS) depressants, CNS stimulants, hallucinogens, designer drugs, and herbal drugs of abuse. We also present brief discussions of alcohol and tricyclic antidepressants as related to urine drug tests, for completeness. The goal of this review was to provide a useful tool for clinicians when interpreting urine drug test results and making appropriate clinical decisions on the basis of the information presented