6,254 research outputs found
The 2D/3D dynamics of wall-bounded low-Rm magnetohydrodynamic (MHD) turbulence
No full textWith this experimental study, we give evidence that the dynamics of low-Rm MHD turbulence depends on the diffusion length l_z, which corresponds to the distance over which the Lorentz force is able to diffuse momentum before it is balanced by inertia
Road map and guide to the gold fields with the newest tracks to the Snowy River [cartographic material] : compiled from the most authenticated government maps of Victoria and New South Wales.
No full textMap of Victoria and southeastern New South Wales divided up into named counties and differentiated by contrasting colours and further divided into squares of 10 miles each. The map features routes to the gold-fields, railways, telegraph lines, tracks, town, and rivers. The map can be used to estimate estimate distances to the goldfields from Melbourne and from Sydney using 50 mile circles. To this end, the map also includes the shorter mountainous route through Beechworth and Lob's Hole to Kiandra, centre of the goldfields, established by Major Freeling in May 1860. All routes given in the tables indicate the distance in miles. Relief is shown by hachures.; "Note: this map is divided into squares of ten miles each, with circles 50 miles apart from the capitals of Victoria and New South Wales".; Includes text entitled: Reference to routes of the principal gold-fields in Victoria ; Routes to the Snowy Mountains gold-fields.; Also available in an electronic version via the Internet at: http://nla.gov.au/nla.map-rm907; National Library's RM 907 Copy 1 is not coloured; Copy 2 is multicoloured. Inset view: The Snowy River diggings, from Kiandra township, 1860
The south eastern portion of Australia showing the routes of the three expeditions and the surveyed territory [cartographic material] /
No full textFrom Vol. 1 of: Three expeditions into the interior of Eastern Australia : with descriptions of the recently explored region of Australia Felix, and of the present colony of New South Wales / by T.L. Mitchell. London, T. & W. Boone, 1838.; Mitchell's map of Victoria and New South Wales showing towns, major rivers and the limits of the Colony at the time. The map shows in red the routes taken by Mitchell's expedition and camps. Relief is shown by hachures and spot heights.; Ferguson, J.A. Bibliography of Australia, 2553; National Library's copies at NK 1476 is very fragile, at RM 916 (Copy 1) is excellent, and at RM 916 (Copy 2) has been repaired along its right side with tape obscuring the far right side of the map.; Rex Nan Kivell Collection Map NK 1476. Inset views entitled Sections of the principal rivers and their banks. Scale 1:2,434: The Karaula, 23rd Jany. 1832 -- Gwydir, 9th Jany. 1832 -- Nammoy, 16th Decr. 1831 -- Darling at Fort Bourke, 10th Augt. 1835 -- Lachlan at Waagan, 24th March 1836 -- Murrumbidgee at Weyeba, 16th May, 1836 -- Murray, 9th June 1836 in long. 136E -- Millewa or Murray, 20th Oct. 1836 in long. 14640' East -- Ovens or Burwang, 16th Octr. 1836 -- Glenelg near the sea, 19th Aug. 1836 -- Glenelg, 14th Augt. 1836 -- Bayungun or Goulburn, 9th Octr. 1836 -- Islands in Bass Strait as seen in the west.Inset: Mouth of the Glenelg, 20th Aug. 1836. Scale [1:28,800], 800 yards to an inch
Triangular Constellations in Flows
No full textParticles advected on the surface of a fluid can exhibit fractal clustering. The local structure of a fractal set is described by its dimension , which is the exponent of a power-law relating the mass in a ball to its radius : . It is desirable to characterise the {\em shapes} of constellations of points sampling a fractal measure, as well as their masses. The simplest example is the distribution of shapes of triangles formed by triplets of points, which we investigate for fractals generated by chaotic dynamical systems. The most significant parameter describing the triangle shape is the ratio of its area to the radius of gyration squared. We show that the probability density of has a phase transition: is independent of and approximately uniform below a critical flow compressibility , which we estimate. For the distribution appears to be described by two power laws: when , and when
Mosquito biology. Evolution of sexual traits influencing vectorial capacity in anopheline mosquitoes
No full textThe availability of genome sequences from 16 anopheline species provides unprecedented opportunities to study the evolution of reproductive traits relevant for malaria transmission. In Anopheles gambiae, a likely candidate for sexual selection is male 20-hydroxyecdysone (20E). Sexual transfer of this steroid hormone as part of a mating plug dramatically changes female physiological processes intimately tied to vectorial capacity. By combining phenotypic studies with ancestral state reconstructions and phylogenetic analyses, we show that mating plug transfer and male 20E synthesis are both derived characters that have coevolved in anophelines, driving the adaptation of a female 20E-interacting protein that promotes oogenesis via mechanisms also favoring Plasmodium survival. Our data reveal coevolutionary dynamics of reproductive traits between the sexes likely to have shaped the ability of anophelines to transmit malaria
Exact two-dimensionalization of low-magnetic-Reynolds-number flows subject to a strong magnetic field
No full textWe investigate the behavior of flows, including turbulent flows, driven by a horizontal body-force and subject to a vertical magnetic field, with the following question in mind: for very strong applied magnetic field, is the flow mostly two-dimensional, with remaining weak three-dimensional fluctuations, or does it become exactly 2D, with no dependence along the vertical? We restrict attention to low-magnetic-Reynolds number (Rm) flow. Because liquid metals have low magnetic Prandtl number, such low- flows can have a kinetic Reynolds number as large as one million and therefore be strongly turbulent. We first focus on the quasi-static approximation, i.e. the asymptotic limit of vanishing magnetic Reynolds number Rm << 1: we prove that the flow becomes exactly 2D asymptotically in time, regardless of the initial condition and provided the interaction parameter N is larger than a threshold value. We call this property absolute two-dimensionalization: the attractor of the system is necessarily a (possibly turbulent) 2D flow. We then consider the full-magnetohydrodynamic equations and we prove that, for low enough Rm and large enough N, the flow becomes exactly two-dimensional in the long-time limit provided the initial vertically-dependent perturbations are infinitesimal. We call this phenomenon linear two-dimensionalization: the (possibly turbulent) 2D flow is an attractor of the dynamics, but it is not necessarily the only attractor of the system. Some 3D attractors may also exist and be attained for strong enough initial 3D perturbations. These results shed some light on the existence of a dissipative anomaly for magnetohydrodynamic flows subject to a strong external magnetic field
The Decay of Wall Bounded MHD Turbulence at Low RM
No full textWe have developed a new spectral method to simulate flows with very fine boundary layers present. We apply it to calculate the evolution of freely decaying MHD turbulence between isolating walls. By comparison them with results obtained in fully periodic domain we quantify the influence of the channel walls on the character of freely decaying MHD turbulence
Patient perceptions of primary care rapid respiratory microbiological point-of-care-testing:a qualitative study
No full textObjectives Rapid microbiological point-of-care tests (RM-POCTs) have the potential to reduce antimicrobial overuse for respiratory tract infections (RTIs). However, patient perspectives regarding RM-POCTs remain unclear. Therefore, this study aimed to explore patients’ and parents’ experiences using RM-POCTs for RTIs and their views on how RM-POCTs influence treatment decisions, symptom management and future consulting.Design A qualitative study using in-depth, semistructured interviews. Data were analysed thematically, informed by a realist approach.Setting Interviewees were recruited from a multicentre, individually randomised controlled efficacy trial evaluating the use of a multiplex RM-POCT for suspected RTIs in primary care.Participants Purposive sample of primary care patients (n=21 adults, 9 parents) participating in the trial.Results In general, participants viewed RM-POCTs favourably. Patients believed RM-POCTs reduced diagnostic uncertainty but emphasised that RM-POCTs should be used alongside clinical judgement. For some, additional information from RM-POCTs created positive outcome expectancies and reduced the perception that antibiotics were necessary. Others felt invalidated by RM-POCTs’ results or believed further support was necessary to understand when antibiotics were needed and how they could manage symptoms. While RM-POCTs may reduce reconsulting for the same illness, participants indicated future consulting behaviours would persist for self-limiting symptoms or health anxiety. Increased consulting may occur if patients perceive RM-POCTs to reduce pressure on primary care.Conclusion RM-POCT offers the potential to improve self-efficacy beliefs and reduce reconsulting for the same illness. Effective clinician communication and patient education may be beneficial alongside RM-POCTs to minimise unintended outcomes and enhance patients’ ability to determine when primary care attendance is necessary in the future.Trial registration number ISRCTN1603919
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