Strong "quantum" chaos in the global ballooning mode spectrum of three-dimensional plasmas

The spectrum of ideal magnetohydrodynamic (MHD) pressure-driven (ballooning) modes in strongly nonaxisymmetric toroidal systems is difficult to analyze numerically owing to the singular nature of ideal MHD caused by lack of an inherent scale length. In this paper, ideal MHD is regularized by using a $k$-space cutoff, making the ray tracing for the WKB ballooning formalism a chaotic Hamiltonian billiard problem. The minimum width of the toroidal Fourier spectrum needed for resolving toroidally localized ballooning modes with a global eigenvalue code is estimated from the Weyl formula. This phase-space-volume estimation method is applied to two stellarator cases.Comment: 4 pages typeset, including 2 figures. Paper accepted for publication in Phys. Rev. Letter

Dermatoses in the Elderly: Biochemical and Haematological Studies, With Special Reference to Serum Proteins

(1.) Literature regarding serum proteins, malnutrition, oedema, protein deficiency and disease of the skin has been reviewed. (2.) One hundred and thirty-seven investigations of serum protein concentrations and of haematological values have been carried out in fifty-two subjects, fifty of whom were over sixty years of age. Eighty-two estimations of serum total base have been carried out in thirty-five subjects. One hundred and thirty-four thymol turbidity values have been determined in fifty-two subjects and gruel fractional test-meals have been carried out in forty-two subjects. Ten normal control subjects who were over sixty years of age have also been investigated. Variations in the blood due to alteration of posture have been demonstrated in eleven subjects. Eighteen subjects with varicose conditions, seventeen with infectious eczematoid dermatitis, nine with scurvy and eight with pemphigus or bullous drug eruptions were investigated. (3.) The erythrocyte sedimentation rate was not related to the state of activity of the skin. (4.) Thymol turbidity estimations were within the normal range in all subjects. (5) In uncomplicated varicose conditions and in uncomplicated infectious eczema told dermatitis the serum total base was within the normal range. (6.) No close relationship between serum protein concentrations and oedema was found. Oedema occurring in uncomplicated infectious eczematoid dermatitis and in uncomplicated varicose conditions in elderly subjects may be explained by local tissue infection and by mechanical factors such as diminished tissue elasticity, impaired lymphatic drainage and local venous congestion. (7.) Significant low concentrations of serum total protein were not found in uncomplicated varicose conditions or in uncomplicated infectious eczematoid dermatitis. Serum total protein concentrations below normal were found in two subjects with scurvy, in one subject with pemphigus vulgaris, in one subject with varicose eczema and drug eruption and in one subject with infectious eczematoid dermatitis and thyrotoxicosis. (8.) The serum albumin concentration was below normal in one subject with pemphigus vulgaris. Low concentrations of serum albumin were commonly found in scurvy and in infectious eczematoid dermatitis. Normochromic, normocytic anaemia was present in the majority of scorbutic subjects and in one third of subjects with infectious eczematoid dermatitis. No relationship was evident between "achlorhydria" and serum protein concentrations or haematological values. (9.) Some evidence was presented that high protein diets were of value in restoring the blood picture to normal in scorbutic subjects and in those with infectious eczematoid dermatitis. Scurvy and infectious eczematoid dermatitis presented some features in common, with respect to the serum albumin concentrations and to the haematological values. Malnutrition may have been a factor in both groups, but it is not possible to state that malnutrition played a definite part in the production of infectious eczematoid dermatitis. (10.) Administration of a high protein diet to scorbutic subjects and to selected elderly subjects who are suffering from infectious eczematoid dermatitis is suggested as a necessary addition to other routine forms of treatment

Opportunities for weed manipulation using GMHT row crops

The herbicides and cultivation systems available in most non-GM crops allow farmers little flexibility as to when they control weeds. However, glyphosate and glufosinate-ammonium, as used in GM herbicide tolerant crops, offer the opportunity to control large weeds and weed control can be timed according to the agronomic and environmental aims of the user. This paper will use sugar beet as a model crop and report results where different approaches to weed control have been used and discuss their relevance in the wider agricultural and environmental contextNon peer reviewe

Geometric combinatorics and computational molecular biology: branching polytopes for RNA sequences

Questions in computational molecular biology generate various discrete optimization problems, such as DNA sequence alignment and RNA secondary structure prediction. However, the optimal solutions are fundamentally dependent on the parameters used in the objective functions. The goal of a parametric analysis is to elucidate such dependencies, especially as they pertain to the accuracy and robustness of the optimal solutions. Techniques from geometric combinatorics, including polytopes and their normal fans, have been used previously to give parametric analyses of simple models for DNA sequence alignment and RNA branching configurations. Here, we present a new computational framework, and proof-of-principle results, which give the first complete parametric analysis of the branching portion of the nearest neighbor thermodynamic model for secondary structure prediction for real RNA sequences.Comment: 17 pages, 8 figure

Hyperglycaemia does not increase perfusion deficits after focal cerebral ischaemia in male Wistar rats

Background: Hyperglycaemia is associated with a worse outcome in acute ischaemic stroke patients; yet the pathophysiological mechanisms of hyperglycaemia-induced damage are poorly understood. We hypothesised that hyperglycaemia at the time of stroke onset exacerbates ischaemic brain damage by increasing the severity of the blood flow deficit. Methods: Adult, male Wistar rats were randomly assigned to receive vehicle or glucose solutions prior to permanent middle cerebral artery occlusion. Cerebral blood flow was assessed semi-quantitatively either 1 h after middle cerebral artery occlusion using 99mTc-D, L-hexamethylpropyleneamine oxime (99mTc-HMPAO) autoradiography or, in a separate study, using quantitative pseudo-continuous arterial spin labelling for 4 h after middle cerebral artery occlusion. Diffusion weighted imaging was performed alongside pseudo-continuous arterial spin labelling and acute lesion volumes calculated from apparent diffusion coefficient maps. Infarct volume was measured at 24 h using rapid acquisition with refocused echoes T2-weighted magnetic resonance imaging. Results: Glucose administration had no effect on the severity of ischaemia when assessed by either 99mTc-HMPAO autoradiography or pseudo-continuous arterial spin labelling perfusion imaging. In comparison to the vehicle group, apparent diffusion coefficient–derived lesion volume 2–4 h post-middle cerebral artery occlusion and infarct volume 24 h post-middle cerebral artery occlusion were significantly greater in the glucose group. Conclusions: Hyperglycaemia increased acute lesion and infarct volumes but there was no evidence that the acute blood flow deficit was exacerbated. The data reinforce the conclusion that the detrimental effects of hyperglycaemia are rapid, and that treatment of post-stroke hyperglycaemia in the acute period is essential but the mechanisms of hyperglycaemia-induced harm remain unclear

Medical Malpractice: A New Treatment for an Old Illness

The rising cost of medical malpractice insurance has been one of the most difficult issues faced by the Florida Legislature for many years. In an effort to reach a comprehensive solution to this recurring problems, the 1986 Legislature created the Academic Task Force for the Review of the Insurance and Tort Systems, and directed it to conduct a thorough review of Florida\u27s tort system. In 1988, the Legislature implemented several of the recommendations of the Task Force. In this Article, the authors explore the factual findings and the recommendations of the Task Force and analyze the effects that the 1988 legislation will have on the continuing medical malpractice saga

Boosting Long-term Memory via Wakeful Rest: Intentional Rehearsal is not Necessary, Automatic Consolidation is Sufficient.

<div><p>People perform better on tests of delayed free recall if learning is followed immediately by a short wakeful rest than by a short period of sensory stimulation. Animal and human work suggests that wakeful resting provides optimal conditions for the consolidation of recently acquired memories. However, an alternative account cannot be ruled out, namely that wakeful resting provides optimal conditions for intentional rehearsal of recently acquired memories, thus driving superior memory. Here we utilised non-recallable words to examine whether wakeful rest boosts long-term memory, even when new memories could not be rehearsed intentionally during the wakeful rest delay. The probing of non-recallable words requires a recognition paradigm. Therefore, we first established, via Experiment 1, that the rest-induced boost in memory observed via free recall can be replicated in a recognition paradigm, using concrete nouns. In Experiment 2, participants heard 30 non-recallable non-words, presented as ‘foreign names in a bridge club abroad’ and then either rested wakefully or played a visual spot-the-difference game for 10 minutes. Retention was probed via recognition at two time points, 15 minutes and 7 days after presentation. As in Experiment 1, wakeful rest boosted recognition significantly, and this boost was maintained for at least 7 days. Our results indicate that the enhancement of memory via wakeful rest is <i>not</i> dependent upon intentional rehearsal of learned material during the rest period. We thus conclude that consolidation is <i>sufficient</i> for this rest-induced memory boost to emerge. We propose that wakeful resting allows for superior memory consolidation, resulting in stronger and/or more veridical representations of experienced events which can be detected via tests of free recall and recognition.</p></div