1,933 research outputs found
Peritonitis. Some experimental and clinical observations on its pathology, prophylaxis and treatment
The impression conveyed to one from a
rapid survey of the vast literature 011 the subject
of Peritonitis is that this literature may be
divided into two clearly defined and widely differing
parts.
The one part dealing with the experimental
side of the subject,is chiefly concerned with
physiological and pathological questions,and to a
less degree with prophylactic measures for peritonltis;
this part is highly scientific in its methods and design.
The other part deals with the methods and
the results of the surgical treatment of Peritonitis
practised in various hospitals and this section
bears for the most part singularly little relation
to the former one.
This separation and lack of co-operation
between the experimental and the clinical workers
on the subject has, one feels sure, retarded the
progress of our treatment of Peritonitis.
The work recorded in this thesis is an
attempt to harmonise and to combine the methods of
experimental research with those of clinical and
practical therapeutics. Whilst this thesis treats
essentially of the use of certain prophylactic and
therapeutic measures for peritoneal infections,
facts of a more purely pathological and bacteriological
nature which were brought out during the
research are ,however,also recorded and discussed
Hardware-in-the-loop tuning of a feedback controller for a buck converter using a GA
This paper presents a methodology for tuning a PID-based feedback controller for a buck converter using the ITAE controller performance index. The controller parameters are optimized to ensure that a reasonable transient response can be achieved whilst retaining stable operation. Experimental results demonstrate the versatility of the on-line tuning methodology
A cascaded H-bridge BLDC drive incorporating battery management
A multilevel BLDC drive is proposed using cascaded H-bridges with isolated sources to provide superior output waveforms and reduced current ripple whilst incorporating observer based SoC estimation. Energy management, based on SoC, is incorporated to improve battery performance, reduce variation between cells and to control charge/discharge profiles
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Neural processing of imminent collision in humans
Detecting a looming object and its imminent collision is imperative to survival. For most humans, it is a fundamental aspect of daily activities such as driving, road crossing and participating in sport, yet little is known about how the brain both detects and responds to such stimuli. Here we use functional magnetic resonance imaging to assess neural response to looming stimuli in comparison with receding stimuli and motion-controlled static stimuli. We demonstrate for the first time that, in the human, the superior colliculus and the pulvinar nucleus of the thalamus respond to looming in addition to cortical regions associated with motor preparation. We also implicate the anterior insula in making timing computations for collision events
First-principles quantum dynamics in interacting Bose gases I: The positive P representation
The performance of the positive P phase-space representation for exact
many-body quantum dynamics is investigated. Gases of interacting bosons are
considered, where the full quantum equations to simulate are of a
Gross-Pitaevskii form with added Gaussian noise. This method gives tractable
simulations of many-body systems because the number of variables scales
linearly with the spatial lattice size. An expression for the useful simulation
time is obtained, and checked in numerical simulations. The dynamics of first-,
second- and third-order spatial correlations are calculated for a uniform
interacting 1D Bose gas subjected to a change in scattering length. Propagation
of correlations is seen. A comparison is made to other recent methods. The
positive P method is particularly well suited to open systems as no
conservation laws are hard-wired into the calculation. It also differs from
most other recent approaches in that there is no truncation of any kind.Comment: 21 pages, 7 figures, 2 tables, IOP styl
The Effect of Natural Dissolved Organic Carbon on the Acute Toxicity of Copper to Larval Freshwater Mussels (\u3cem\u3eGlochidia\u3c/em\u3e)
The present study examined the effect of dissolved organic carbon (DOC), both added and inherent, on Cu toxicity in glochidia, the larvae of freshwater mussels. Using incremental additions of natural DOC concentrate and reconstituted water, a series of acute copper toxicity tests were conducted. An increase in DOC from 0.7 to 4.4 mg C/L resulted in a fourfold increase (36â150 ÎŒg Cu/L) in the 24-h median effective concentration (EC50) and a significant linear relationship (r2=0.98, p=0.0008) between the DOC concentration and the Cu EC50 of Lampsilis siliquoidea glochidia. The ameliorating effect of added DOC on Cu toxicity was confirmed using a second mussel species, the endangered (in Canada) Lampsilis fasciola. The effect of inherent (i.e., not added) DOC on Cu toxicity was also assessed in eight natural waters (DOC 5â15 mg C/L). These experiments revealed a significant relationship between the EC50 and the concentration of inherent DOC (r2=0.79, p=0.0031) with EC50s ranging from 27 to 111 ÎŒg Cu/L. These laboratory tests have demonstrated that DOC provides glochidia with significant protection from acute Cu toxicity. The potential risk that Cu poses to mussel populations was assessed by comparing Cu and DOC concentrations from significant mussel habitats in Ontario to the EC50s. Although overall mean Cu concentration in the musselâs habitat was well below the acutely toxic level given the concentration of DOC, episodic Cu releases in low DOC waters may be a concern for the recovery of endangered freshwater mussels. The results are examined in the context of current Cu water quality regulations including the U.S. Environmental Protection Agencyâs (U.S. EPA) biotic ligand model
A software process improvement lifecycle framework for the medical device industry
This paper describes a software process improvement framework to ensure regulatory compliance for the software developed in medical devices. Software is becoming an increasingly important aspect of medical devices and medical device regulation. Medical devices can only be marketed if compliance and approval from the appropriate regulatory bodies of the Food and Drug Administration (FDA) [1] (US requirement), and the European Commission under its Medical Device Directives (MDD) [2] (CE marking requirement) is achieved.
Integrated into the design process of medical devices, is the requirement of the production and maintenance of a device technical file, incorporating a design history file. Design history illustrates the well documented, defined and controlled processes and outputs, undertaken in the development of medical devices and for our particular consideration with this framework - the software components
When is Quantum Decoherence Dynamics Classical?
A direct classical analog of quantum decoherence is introduced. Similarities
and differences between decoherence dynamics examined quantum mechanically and
classically are exposed via a second-order perturbative treatment and via a
strong decoherence theory, showing a strong dependence on the nature of the
system-environment coupling. For example, for the traditionally assumed linear
coupling, the classical and quantum results are shown to be in exact agreement.Comment: 5 pages, no figures, to appear in Physical Review Letter
The Heliogyro Reloaded
The heliogyro is a high-performance, spinning solar sail architecture that uses long - order of kilometers - reflective membrane strips to produce thrust from solar radiation pressure. The heliogyro s membrane blades spin about a central hub and are stiffened by centrifugal forces only, making the design exceedingly light weight. Blades are also stowed and deployed from rolls; eliminating deployment and packaging problems associated with handling extremely large, and delicate, membrane sheets used with most traditional square-rigged or spinning disk solar sail designs. The heliogyro solar sail concept was first advanced in the 1960s by MacNeal. A 15 km diameter version was later extensively studied in the 1970s by JPL for an ambitious Comet Halley rendezvous mission, but ultimately not selected due to the need for a risk-reduction flight demonstration. Demonstrating system-level feasibility of a large, spinning heliogyro solar sail on the ground is impossible; however, recent advances in microsatellite bus technologies, coupled with the successful flight demonstration of reflectance control technologies on the JAXA IKAROS solar sail, now make an affordable, small-scale heliogyro technology flight demonstration potentially feasible. In this paper, we will present an overview of the history of the heliogyro solar sail concept, with particular attention paid to the MIT 200-meter-diameter heliogyro study of 1989, followed by a description of our updated, low-cost, heliogyro flight demonstration concept. Our preliminary heliogyro concept (HELIOS) should be capable of demonstrating an order-of-magnitude characteristic acceleration performance improvement over existing solar sail demonstrators (HELIOS target: 0.5 to 1.0 mm/s2 at 1.0 AU); placing the heliogyro technology in the range required to enable a variety of science and human exploration relevant support missions
âsome kind of thing it aint us but yet its in usâ: David Mitchell, Russell Hoban, and metafiction after the millennium
This article appraises the debt that David Mitchellâs Cloud Atlas owes to the novels of Russell Hoban, including, but not limited to, Riddley Walker. After clearly mapping a history of Hobanâs philosophical perspectives and Mitchellâs inter-textual genre-impersonation practice, the article assesses the degree to which Mitchellâs metatextual methods indicate a nostalgia for by-gone radical aesthetics rather than reaching for new modes of its own. The article not only proposes several new backdrops against which Mitchellâs novel can be read but also conducts the first in-depth appraisal of Mitchellâs formal linguistic replication of Riddley Walker
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