Finite Larmor radius influence on MHD solitary waves

MHD solitons are studied in a model where the usual Hall-MHD model is extended to include the finite Larmor radius (FLR) corrections to the pressure tensor. The resulting 4-dimensional set of differential equations is treated numerically. In this extended model, the point at infinity can be of several types. Necessary for the existence of localized solutions is that it is either a saddle-saddle, a saddle-center, or, possibly, a focus-focus. In cases of saddle-center, numerical solutions for localized travelling structures have been obtained, and compared with corresponding results from the Hall-MHD model

Nature reserves as a bioeconomic management tool. A simplified modeling approach

This paper demonstrates analytically how a nature reserve may protect the total population, realize maximum sustainable yield (MSY), maximum economic yield (MEY) and consumer surplus (CS) and how this depends on biological growth, migration, reserve size and economic parameters. The pre-reserve population is assumed to follow the logistic growth law and two post-reserve growth models are discussed. For Model A, the post-reserve growth has a common carrying capacity as in the pre-reserve case. In Model B, each sub-population has its own carrying capacity proportionate to its distribution area. Population protection against extinction is assured against low cost harvesting, including zero cost, when relative reserve size is greater than relative migration. Reserve size may be tuned to realize MSY in Model A, but not in Model B. MEY can not be realized in any of the two models, but generally economic yield is greater in Model A than B. CS is greater with a reserve than without

The Effect of High-Intensity Interval/Circuit Training on Cognitive Functioning and Quality of Life During Recovery From Substance Abuse Disorder. A Study Protocol

This proposed study will examine whether structured physical activity reduces the recovery time of cognitive functioning during the early phase of substance use disorder treatment. Addiction or substance dependence is associated with neurobiological changes and cognitive impairment that can affect quality of life and the efficacy of therapy for up to a year after clinical detoxification. The biological, psychological, and social effects of physical exercise have the potential to be a therapeutic approach to increase quality of life and relieve symptoms associated with substance abuse, such as psychosis, depression, and anxiety. There is a dearth of research on physical activity and exercise in clinical substance use disorder patients. This protocol describes a clinical study that will examine cognitive recovery after substance abuse using physical exercise as a treatment intervention. We will use a quasi-experimental longitudinal clinical trial, with a pretest and multiple posttests, on naturally randomized sequential groups. Patients will be consecutively be recruited into the study groups, with a control group that is completed, before its followed by an intervention group, each with 30 patients. Patients will be enrolled 2 weeks after the start of detoxification, at which time all subjects will be inpatients at the Stavanger Salvation Army Treatment Center in the Norwegian specialized healthcare system. Cognition will be evaluated with a comprehensive battery of cognitive tests, including several tests of executive function. Physical fitness will be tested with the Rockport 1-Mile Walk Test, the 30-S Chair Stand Test, the 1-Min Burpee Test at baseline (within the first 2 weeks of admittance) and after 4 weeks. The intervention will be a 30-min workout at 70–90% of maximum heart rate (134–170 bpm), recorded and calculated by a Polar heart rate monitor. The intervention treatment will be administered four times a week for 4 weeks and will consist of high-intensity circuit training, high-intensity interval training, functional movement, and primitive reflex training. We anticipate improvement in both the control and intervention groups, with the exercise intervention group having the greatest increase in recovery of cognitive function because of the combination of functional full body movements and primitive movement training in an intense interval training program.publishedVersio

Nature Reserves as a Bioeconomic Management Tool: A Simplified Modelling Approach

Extinction, Marine reserve, Maximum sustainable yield, Nature reserve, Resource management, Wildlife reserve, Q20,