3,384 research outputs found
Birds surveyed in the harvested and unharvested areas of a reduced-impact logged forestry concession, located in the lowland subtropical humid forests of the Department of Santa Cruz, Bolivia.
As part of a larger study of reduced-impactlogging effects on bird community composition,we surveyed birds from December to Februaryduring the 2003-2004 wet-season within harvestedand unharvested blocks of the La Chonta forestryconcession, Department of Santa Cruz, Bolivia.The logged forest was harvested using reduced-impactlogging techniques between one and fouryears previously. During point count surveys, weidentified 5062 individual birds, belonging to 155species, and 33 families. We provide a list of birdspecies found within the harvested andunharvested blocks of the concession for thebenefit of other researchers assessing theresponses of Neotropical avifauna to disturbance,and to facilitate increased understanding of thediverse bird assemblages found within thelowland subtropical humid forests of Bolivia
Modeling and parameter uncertainties for aircraft flight control system design
Values of plant dynamic uncertainties for some recent aircraft design and development programs are given. Histories of pertinent aerodynamic, inertial, and structural parameter variations are given for a period of time from program initiation to aircraft certification. These data can be used as typical of future vehicles so that control system design concepts are evaluated with due consideration to their sensitivity to uncertainties in plant dynamics
Detailed investigation of a vaporising fuel spray. Part 1: Experimental investigation of time averaged spray
A laser tomographic light scattering technique provides rapid and accurate high resolution measurements of droplet sizes, concentrations, and vaporization. Measurements using a computer interfaced thermocouple are presented and it is found that the potential exists for separating gas and liquid temperature measurements and diagnosing local spray density by in situ analysis of the response characteristics of the thermocouple. The thermocouple technique provides a convenient means for measuring mean gas velocity in both hot and cold two phase flows. The experimental spray is axisymmetric and has carefully controlled initial and boundary conditions. The flow is designed to give relatively insignificant transfer of momentum and mass from spray to air flow. The effects of (1) size-dependent droplet dispersion by the turbulence, (2) the initial spatial segregation of droplet sizes during atomization, and (3) the interaction between droplets and coherent large eddies are diagnosed
How severe is antibiotic pharmacokinetic variability in critically ill patients and what can be done about it?
The pharmacokinetics (PK) of antimicrobial agents administered to critically ill patients exhibit marked variability. This variability results from pathophysiological changes that occur in critically ill patients. Changes in volume of distribution, clearance, and tissue penetration all affect the drug concentrations at the site of infection. PK-pharmacodynamic indices (fC(max):MIC; AUC(0-24):MIC; fT(>MIC); fC(min):MIC) for both antimicrobial effect and suppression of emergence of resistance are described for many antimicrobial drugs. Changing the regimen by which antimicrobial drugs are delivered can help overcome the PK variability and optimise target attainment. This will deliver optimised antimicrobial chemotherapy to individual critically ill patients. Delivery of beta-lactams antimicrobial agents by infusions, rather than bolus dosing, is effective at increasing the duration of the dosing interval that the drug concentration is above the MIC. Therapeutic drug monitoring, utilising population PK mathematical models with Bayesian estimation, can also be used to optimise regimens following measurement of plasma drug concentrations. Clinical trials are required to establish if patient outcomes can be improved by implementing these techniques. (C) 2014 Elsevier Inc. All rights reserved
Effects of low energy electron irradiation on formation of nitrogen-vacancy centers in single-crystal diamond
Exposure to beams of low energy electrons (2 to 30 keV) in a scanning
electron microscope locally induces formation of NV-centers without thermal
annealing in diamonds that have been implanted with nitrogen ions. We find that
non-thermal, electron beam induced NV-formation is about four times less
efficient than thermal annealing. But NV-center formation in a consecutive
thermal annealing step (800C) following exposure to low energy electrons
increases by a factor of up to 1.8 compared to thermal annealing alone. These
observations point to reconstruction of nitrogen-vacancy complexes induced by
electronic excitations from low energy electrons as an NV-center formation
mechanism and identify local electronic excitations as a means for spatially
controlled room-temperature NV-center formation
Groundwater Flow and Elastoplastic Stress-Strain Model for Cohesive Soils with Application to Channel Bank Stability
A saturated-unsaturated groundwater flow and elastoplastic stress-strain finite element model was developed for simulating the mechanical behavior of rill and gully sized channel banks. The model coupled the two-dimensional saturated-unsaturated groundwater flow equation with a plane strain formulation of the virtual work equation. The constitutive relationship used the modified Cam clay yield function. The model included the effects of seepage force and variation in soil cohesive strength due to changes in water content and void ratio. A staggered solution procedure was used in which the groundwater equation was solved first to determine seepage force and soil cohesive force, and then the stress-strain equation was solved. Upon reaching the failure point, the elastoplastic constitutive relationship was replaced with a weak elastic relationship.
The model was verified by comparing predictions with (1) one-dimensional analytic solutions for unsaturated flow, saturated flow, and elastic strain; (2) other numerical solutions using the modified Cam clay yield function; (3) triaxial tests; and (4) laboratory experiments. The laboratory experiments employed a specially designed cyclic soil compactor and plexiglass flume to form and compact channel banks. The channel banks were subjected to a rising and falling hydrograph.
Model simulation included groundwater movement into the channel bank, strain in the x-direction, and the location of finite elements which reached ultimate strength. Failure surfaces were delineated by zones of high x-strain in conjunction with finite elements which reached ultimate strength. The model provided good insight into the failure mechanism for popout failure and a reasonable prediction of plane failure
Longitudinal study of local authority child and family social workers (wave 1) Findings from a 5 year study of local authority child and family social workers in England.
The longitudinal study investigates recruitment, retention and career progression in local authority child and family social work over 5 years. This is the first of 5 reports.
It provides workforce information for employers and policy makers.
Topics covered in this report include:
•entry routes into local authority child and family social work
•current employment and career history
•workplace wellbeing
•management, supervision and working environment
•job satisfaction
•career progression and future career plan
Developement of real time diagnostics and feedback algorithms for JET in view of the next step
Real time control of many plasma parameters will be an essential aspect in
the development of reliable high performance operation of Next Step Tokamaks.
The main prerequisites for any feedback scheme are the precise real-time
determination of the quantities to be controlled, requiring top quality and
highly reliable diagnostics, and the availability of robust control algorithms.
A new set of real time diagnostics was recently implemented on JET to prove the
feasibility of determining, with high accuracy and time resolution, the most
important plasma quantities. With regard to feedback algorithms, new
model–based controllers were developed to allow a more robust control of
several plasma parameters. Both diagnostics and algorithms were successfully
used in several experiments, ranging from H-mode plasmas to configuration with
ITBs. Since elaboration of computationally heavy measurements is often
required, significant attention was devoted to non-algorithmic methods like
Digital or Cellular Neural/Nonlinear Networks. The real time hardware and
software adopted architectures are also described with particular attention to
their relevance to ITER.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004,
Nice (France
Groundwater Study: Toyota Motor Manufacturing, USA Georgetown, Kentucky
An eighteen month study of the Toyota Motor Manufacturing (TMM) plant site and the surrounding area was undertaken. The basic charge for this project was to characterize the groundwater that is potentially impacted by the TMM plant site. This included occurrence, flow direction, and, if possible, velocity. Because the area is karstified (has sinkholes, springs, caves, etc.) surface water and groundwater are intimately connected and, hence, surface water was frequently an important component of this work.
Data from TMM construction plans and monitoring work done subsequent to construction were elicited from the various repositories within the TMM infrastructure. Aerial color photographs were acquired from various government agencies. Maps were constructed from the various data sources and data layers were combined to provide a complete picture of the plant site with respect to geology and groundwater. Fracture trace analysis and field reconnaissance was performed. Fifty-one sinkholes were found onsite, 182 in the entire study area. Several springs, both onsite and offsite, were discovered. Dye trace analysis was performed to determine connectivity and help to build a conceptual model of the subsurface flow system. Existing chemical analysis was complemented with chemical analysis done by the University of Kentucky
Pedestrian Infrastructure Improvements: Effects on Transit Use and Perceptions of the Pedestrian Environment in Portland\u27s Roseway Neighborhood
Over the past two years the Pedestrian Transportation (PTP) of the City of Portland has been engaged in a project to encourage walking and transit use through targeted infrastructure improvements. These improvements are intended to enhance pedestrian access to transit service by aiding street crossing and providing more amenities at bus stops. Other improvements include landscaping, sidewalks, curb extensions and ramps, and improved street lighting. One of the basic assumptions of this project is that the pedestrian environment is related to transportation choices. This report explores that assumption
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