4,842 research outputs found
Alien Registration- Caron, David (Lewiston, Androscoggin County)
https://digitalmaine.com/alien_docs/29724/thumbnail.jp
Developing R&D capacity in a primary care trust : use of the R&D culture index
There has traditionally been a low level of engagement of primary care practitioners with research. In the UK, primary care trusts (PCTs) now have some responsibility for the encouragement of research and development in primary care. The aim of this study was to assess the current level of research activity and capacity for research within a PCT. A questionnaire, incorporating a recently developed and validated research and development culture index, was sent to all 572 health care professionals and staff under the auspices of North Tyneside Research PCT. Data analysis used nonparametric tests of association including chi-squared, MannâWhitney U and Spearman's rank order correlation. There was a 50.3 per cent response rate to the questionnaire. Groups more likely to show an increased capacity for research included those with postgraduate qualifications and those in post for the least time. General practitioners were less likely than other professional groupings to declare personal skills or aptitude for research. The two most important factors thought to contribute towards the development of a culture of R&D were having access to people to support development and changes in professional practice and having access to training and development opportunities. The use of the R&D culture index enabled groups to be identified that may be more research interested and can therefore be targeted to increase research capacity. The R&D culture index could be used by other PCTs wishing to define and develop research capacity in primary care
Investigation Of Ions Accelerated Through Electrostatic Menisci In An Inductively Coupled Plasma
Plasmas are used in semiconductor fabrication as they allow for very precise control over processes such as etching and doping. This is achieved by extracting a beam of ions from the plasma to interact with and modify the surface of a silicon wafer. However, conventional fabrication methods are reaching spatial limitations as semiconductor features reach the atomic scale. Therefore, in order to better control the fabrication processes and facilitate the transition to three-dimensional architecture, a greater understanding of ion beam formation is needed. Ion beams are extracted at the boundary between the Debye sheath and an externally applied potential, which forms a unipolar sheath. This boundary, known as the plasma meniscus, is dependent on source parameters and acts as an electrostatic lens for ions that traverse it. This allows for control of ion beam properties through the adjustment of the source parameters that affect the meniscus. Presented here is an investigation into the plasma meniscus and the dependence of its topology on controllable source parameters. The plasma meniscus is formed by graphite extraction optics with a 5 mm square aperture for beam extraction. 12 mm from the aperture is an electrically isolated graphite wafer that is biased to different potentials. Laser induced fluorescence is employed to obtain ion velocity distribution functions: inside the inductively coupled plasma source, at the extraction aperture, and in the downstream ion beam. The use of the confocal telescope allows for first, non-perturbative measurements of ions inside an inductively coupled plasma source. The ion source power is varied (Pf = 1 kW, 2 kW, 3 kW, 4 kW) at different applied wafer bias voltages (Vb = 0 V, 1000 V, 2000 V, 3000 V). Ion temperature, velocity, and relative density are calculated from the ion velocity distribution functions. The ions\u27 speed increases as they travel through the source and form the beam. Additionally, there is a second population of ions that appears near the plasma meniscus. These ions form a beam halo, which hinders the creation of a uniform ion beam. This effect is mitigated at a sufficiently high bias voltage
The role of heterotrophic microflagellates in plankton communities
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 1984The distribution and feeding behavior of bacterivorous micro flagellates
(2-20 ÎŒm protozoa) and their ingestion by copepods were examined in an attempt
to assess the importance of these protozoa as a trophic link between
planktonic bacteria and zooplankton. The abundance of microflagellates
relative to other picoplankton (0.2-2.0 ÎŒm) and nanoplankton (2-20 ÎŒm)
populations in water samples in the North Atlantic and in Lake Ontario and on
macroaggregates in the North Atlantic was determined using direct
microscopical and culture estimation techniques. Seasonal, vertical and
geographical changes in the density of microflagellates were generally not
greater than one order of magnitude. Microscopical counts of heterotrophic
nanoplankton (presumably microflagellates) typically ranged from a few hundred
to a few thousand m1-1 for a variety of planktonic environments. They
constituted approximately 1/3 to 1/2 of the nanoplankton in the euphotic zone
and dominated the nanoplankton in the aphotic zone. Most Probable Number
(MPN) estimation of the density of bacterivorous protozoa indicated that
microflagellates were, on average, an order of magnitude more abundant than
bacterivorous ciliates and amoebae. MPN and direct microscopical counts of
microflagellates differed by as much as 104. This discrepancy was smaller
in eutrophic environments (e.g. Continental Shelf and Lake Ontario) and on
macroscopic detrital aggregates.
All microbial populations enumerated were highly concentrated on
macroscopic detrital aggregates relative to their abundance in the water
surrounding the aggregates. Enrichment factors (the ratio of abundance of a
population on a macroaggregate to its abundance in the surrounding water)
increased along a eutrophic-to-oligotrophic gradient because of the combined
effects of an increased abundance of microorganisms on macroaggregates in
oligotrophic environments and a decreased abundance in the surrounding water
in these same environments. Average enrichment factors for direct
microscopical counts of heterotrophic nanoplankton (range = 17-114) were not
as large as enrichment factors observed for MPN estimates of the number of
bacterivorous microflagellates (range = 273-18400). Microflagellates
numerically dominated the bacterivorous protozoa cultured from macroaggregates
by one to two orders of magnitude, but ciliates and amoebae were also highly
enriched on macroaggregates. Microenvironments are therefore a potentially
important aspect for the ecology of planktonic microorganisms. Observations
on the microbial colonization of mucus sloughed by ctenophores and discarded
appendicularian houses suggest that these materials may be important sources
of macroaggregates.
Batch and continuous culture experiments were conducted with clonal
cultures of microflagellates to test their ability to grow on various types
and densities of bacteria. The doubling time of Monas sp. 1 ranged from 43 hr
(when fed the cyanobacterium Synechococcus Strain WH 8101) to 6.9 hr (when fed
the heterotrophic bacterium Serratia marinorubra). Cell yields (i.e. the
conversion of bacterial biomass into protozoan biomass) of Monas sp. 1 fed two
species of heterotrophic bacteria were greater than yields for the
microflagellate fed two species chroococcoid cyanobacteria (range = 7-68%).
Cell yields of two other species of microflagellates (Monas sp. 2 and
Cryptobia maris) were 48% and 61%, respectively, on the bacterium Pseudomonas
halodurans. Microflagellates grew in continuous culture at concentrations of
bacteria which were lower than bacterial densities required for the growth of
ciliates as shown by other investigations. Therefore, microflagellates appear
to be well-adapted for grazing bacterioplankton.
Microflagellates were also investigated for their ability to graze
bacteria attached to particles. Bodo nanorensis and Rhynchomonas nasuta both
showed a marked ability to graze attached bacteria and a limited ability to
graze unattached cells. These results suggest that microflagellates may also
be important consumers of bacteria attached to particles in the plankton and
may explain the highly elevated densities of microflagellates on
macroaggregates.
Grazing experiments performed with the copepod Acartia tonsa indicated
that heterotrophic microflagellates were ingested by the copepods at rates
comparable to the ingestion of phytoplankton of similar size. The presence of
heterotrophic microflagellates did not depress filtration rates of the
copepods, and one species (Cryptobia maris) appeared to be selectively
grazed. Survival of A. tonsa on a diet of heterotrophic microflagellates was
similar to survival on a diet of phytoplankton and was significantly longer
than survival of starved Controls or copepods fed only bacteria.
Due to their ability to grow at in-situ densities of planktonic bacteria,
their relatively high cell yields, and their acceptability as food for
zooplankton, it is concluded that bacterivorous microflagellates may
constitute an important trophic link between bacteria and zooplankton. This
link may provide a mechanism whereby organic material and energy from the
detrital food chain can be returned to the classical phytoplankton-copepod-fish food chain.This research was supported by National Science Foundation grants
OCE80-2444l and OCE82-l4928 and Ocean Industry Program grant 4473 awarded to
Dr. Laurence P. Madin, NSF Doctoral Dissertation grant OCE8l-l299l, the Woods
Hole Oceanographic Institution Education Program and the Wood Hole
Oceanographic Institution Biology Department
Two-sample Bayesian Nonparametric Hypothesis Testing
In this article we describe Bayesian nonparametric procedures for two-sample
hypothesis testing. Namely, given two sets of samples
\stackrel{\scriptscriptstyle{iid}}{\s
im} and \stackrel{\scriptscriptstyle{iid}}{\sim},
with unknown, we wish to
evaluate the evidence for the null hypothesis
versus the
alternative . Our
method is based upon a nonparametric P\'{o}lya tree prior centered either
subjectively or using an empirical procedure. We show that the P\'{o}lya tree
prior leads to an analytic expression for the marginal likelihood under the two
hypotheses and hence an explicit measure of the probability of the null
.Comment: Published at http://dx.doi.org/10.1214/14-BA914 in the Bayesian
Analysis (http://projecteuclid.org/euclid.ba) by the International Society of
Bayesian Analysis (http://bayesian.org/
Trajectory design for autonomous underwater vehicles based on ocean model predictions for feature tracking
Trajectory design for Autonomous Underwater Vehicles (AUVs) is of great importance to the oceanographic research community. Intelligent planning is required to maneuver a vehicle to high-valued locations for data collection. We consider the use of ocean model predictions to determine the locations to be visited by an AUV, which then provides near-real time, in situ measurements back to the model to increase the skill of future predictions. The motion planning problem of steering the vehicle between the computed waypoints is not considered here. Our focus is on the algorithm to determine relevant points of interest for a chosen oceanographic feature. This represents a first approach to an end to end autonomous prediction and tasking system for aquatic, mobile sensor networks. We design a sampling plan and present experimental results with AUV retasking in the Southern California Bight (SCB) off the coast of Los Angeles
Reinventing Maine Government: How Mainers Can Shape a Sustainable Government and a New Prosperity
In this commentary the authors highlight the challenges Maine faces. They suggest areas where the state could spend less, based on national comparative figures. They discuss what they call the âthree ticking time bombsâ in the state: the aging workforce, unfunded pension liabilities, and escalating costs of healthcare, and review what they consider to be inefficient structures in government at all levels. They argue that new thinking and new approaches are needed, and make a number of recommendations for âreinventing governmentâ in Maine
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