title: Evolution of energy-containing turbulent eddies in the solar wind

authors: Matthaeus, William H.

abstract: Previous theoretical treatments of fluid-scale turbulence in the solar wind have concentrated on describing the state and dynamical evolution of fluctuations in the inertial range, which are characterized by power law energy spectra. In the present paper a model for the evolution of somewhat larger, more energetic magnetohydrodynamic (MHD) fluctuations is developed by analogy with classical hydrodynamic turbulence in the quasi-equilibrium range. The model is constructed by assembling and extending existing phenomenologies of homogeneous MHD turbulence, as well as simple two-length-scale models for transport of MHD turbulence in a weakly inhomogeneous medium. A set of equations is presented for the evolution of the turbulence, including the transport and nonlinear evolution of magnetic and kinetic energy, cross helicity, and their correlation scales. Two versions of the model are derived, depending on whether the fluctuations are distributed isotropically in three dimensions or restricted to the two-dimensional plane perpendicular to the mean magnetic field. This model includes a number of potentially important physical effects that have been neglected in previous discussions of transport of solar wind turbulence. Numerical solutions are shown for several cases of interest that demonstrate the advantages of this approach. We suggest that this model may prove useful in studies of solar wind heating and acceleration, as well as in describing the response of interplanetary turbulence to wave energy injected by pickup ions and planetary upstream waves.

text: Evolution of energy-containing turbulent eddies in the solar wind Previous theoretical treatments of fluid-scale turbulence in the solar wind have concentrated on describing the state and dynamical evolution of fluctuations in the inertial range, which are characterized by power law energy spectra. In the present paper a model for the evolution of somewhat larger, more energetic magnetohydrodynamic (MHD) fluctuations is developed by analogy with classical hydrodynamic turbulence in the quasi-equilibrium range. The model is constructed by assembling and extending existing phenomenologies of homogeneous MHD turbulence, as well as simple two-length-scale models for transport of MHD turbulence in a weakly inhomogeneous medium. A set of equations is presented for the evolution of the turbulence, including the transport and nonlinear evolution of magnetic and kinetic energy, cross helicity, and their correlation scales. Two versions of the model are derived, depending on whether the fluctuations are distributed isotropically in three dimensions or restricted to the two-dimensional plane perpendicular to the mean magnetic field. This model includes a number of potentially important physical effects that have been neglected in previous discussions of transport of solar wind turbulence. Numerical solutions are shown for several cases of interest that demonstrate the advantages of this approach. We suggest that this model may prove useful in studies of solar wind heating and acceleration, as well as in describing the response of interplanetary turbulence to wave energy injected by pickup ions and planetary upstream waves.

year: 1994

title: Chronic Intermittent Sucrose Consumption Facilitates the Ability to Discriminate Opioid Receptor Blockade with Naltrexone in Rats

authors: Jewett, David C.

subjects: Science & Technology

abstract: The opioid antagonist naltrexone (NTX) decreases intake of preferred diets in rats at very low doses relative to doses needed to decrease intake of “bland” laboratory chow. In the absence of an opioid agonist, NTX is not discriminable using operant techniques. In the current study, we found that rats given intermittent access to a 25% sucrose solution learned to discriminate between various naltrexone doses and saline. None of the rats given only water learned to discriminate between naltrexone and saline. When access to the sucrose solution was discontinued for 14 days, the rats lost the ability to discriminate between NTX and saline. We also studied the changes of c-Fos IR in selected brain regions in rats treated with saline versus NTX that were drinking water or 25% sucrose. An injection of NTX or saline resulted in a significant drug, diet, and interaction effect in various brain regions associated with feeding behavior, particularly the amygdala, accumbens, and hypothalamic sites. Thus, we found that ingestion of a sucrose solution results in the ability of rats to reliably discriminate naltrexone administration. In addition, sucrose and naltrexone altered c-Fos IR in an interactive fashion in brain regions known to be involved in ingestion behavior.

text: Chronic Intermittent Sucrose Consumption Facilitates the Ability to Discriminate Opioid Receptor Blockade with Naltrexone in Rats The opioid antagonist naltrexone (NTX) decreases intake of preferred diets in rats at very low doses relative to doses needed to decrease intake of “bland” laboratory chow. In the absence of an opioid agonist, NTX is not discriminable using operant techniques. In the current study, we found that rats given intermittent access to a 25% sucrose solution learned to discriminate between various naltrexone doses and saline. None of the rats given only water learned to discriminate between naltrexone and saline. When access to the sucrose solution was discontinued for 14 days, the rats lost the ability to discriminate between NTX and saline. We also studied the changes of c-Fos IR in selected brain regions in rats treated with saline versus NTX that were drinking water or 25% sucrose. An injection of NTX or saline resulted in a significant drug, diet, and interaction effect in various brain regions associated with feeding behavior, particularly the amygdala, accumbens, and hypothalamic sites. Thus, we found that ingestion of a sucrose solution results in the ability of rats to reliably discriminate naltrexone administration. In addition, sucrose and naltrexone altered c-Fos IR in an interactive fashion in brain regions known to be involved in ingestion behavior.

year: 2022-03-01

title: The Waikato invasion 1863-1864: A counter-insurgency approach

authors: Swears, Calum Robert

subjects: Counterinsurgency

abstract: Counter-insurgency as a strategy has only been explicitly espoused in American and British military tactical manuals in recent decades. It is anachronistic to military terminology before the last half century, but as this thesis illustrates counter-insurgency can be seen in embryonic form in the conflicts of the 1860s between Indigenous Māori and invading British forces in Aotearoa New Zealand. This thesis examines how early counter-insurgency strategy was evident in the tactical and strategic approaches used by Crown forces during the invasion of the Waikato in 1863-64. It asks: what evidence of counter-insurgency strategy can be seen in both British and Māori tactics at the time, and were they planned and intentional? 
Using two recent counter-insurgency tactical manuals - one American and the other British - this study compares present-day counter-insurgency principles, philosophies, and approaches to examples of Māori and British strategies during the 1860’s wars in Waikato, New Zealand. It illustrates how the Crown’s “suppression of rebellion” served as the contemporary political wording for its counter-insurgency campaign, which effectively repositioned Indigenous peoples as insurgents and “rebels” in their own territories and legitimated British colonial authority. Thus, this study argues that counter-insurgency in British military history arose from the various colonial invasions and occupations it undertook over several centuries. In Aotearoa, as this thesis argues, counter-insurgency tactics were used to establish legitimacy through civil-military operations such as land seizure, public proclamations and reports that vilified Māori and asserted British governing authority. The history of counter-insurgency as it is understood in British and American military thinking today, then, as this study contends is deeply connected to, and informed by, powerful colonial discourses, strategies, and experiences similar to those explored in this study of the Waikato invasion.

text: The Waikato invasion 1863-1864: A counter-insurgency approach Counter-insurgency as a strategy has only been explicitly espoused in American and British military tactical manuals in recent decades. It is anachronistic to military terminology before the last half century, but as this thesis illustrates counter-insurgency can be seen in embryonic form in the conflicts of the 1860s between Indigenous Māori and invading British forces in Aotearoa New Zealand. This thesis examines how early counter-insurgency strategy was evident in the tactical and strategic approaches used by Crown forces during the invasion of the Waikato in 1863-64. It asks: what evidence of counter-insurgency strategy can be seen in both British and Māori tactics at the time, and were they planned and intentional? 
Using two recent counter-insurgency tactical manuals - one American and the other British - this study compares present-day counter-insurgency principles, philosophies, and approaches to examples of Māori and British strategies during the 1860’s wars in Waikato, New Zealand. It illustrates how the Crown’s “suppression of rebellion” served as the contemporary political wording for its counter-insurgency campaign, which effectively repositioned Indigenous peoples as insurgents and “rebels” in their own territories and legitimated British colonial authority. Thus, this study argues that counter-insurgency in British military history arose from the various colonial invasions and occupations it undertook over several centuries. In Aotearoa, as this thesis argues, counter-insurgency tactics were used to establish legitimacy through civil-military operations such as land seizure, public proclamations and reports that vilified Māori and asserted British governing authority. The history of counter-insurgency as it is understood in British and American military thinking today, then, as this study contends is deeply connected to, and informed by, powerful colonial discourses, strategies, and experiences similar to those explored in this study of the Waikato invasion.

year: 2022