2,154 research outputs found
Alien Registration- Lebel, Cecile B. (Van Buren, Aroostook County)
https://digitalmaine.com/alien_docs/33217/thumbnail.jp
Alien Registration- Lebel, John B. (Van Buren, Aroostook County)
https://digitalmaine.com/alien_docs/33215/thumbnail.jp
Technical Efficiency Evaluation of Logging Contractors Using a Nonparametric Model
Data Envelopment Analysis (DEA) models were used to measure the technical efficiency of a sample of logging contractors. DEA is a nonparametric efficiency measurement technique based on linear programming methods. This paper demonstrates how DEA models can be applied in a forest operations context to gain insights on the factors which affect technical efficiency and performance.
Twenty-three fully mechanized loggers were compared in regards to the efficiency with which they converted inputs – dollars of capital, consumables, and labor – into output – tons of wood. Overall, for the period of 1988 to 1994, the logging contractors studied were efficient, but some were considerably less efficient than others. Low capacity utilization had a negative impact on technical efficiency. The scale of an operation also influenced technical efficiency. For the sample, the most productive scale size was estimated to be around 75,000 tons per year
Histamine production during the anti-allograft response. Demonstration of a new lymphokine enhancing histamine synthesis
Histamine production is greatly increased during culture of allograft recipient spleen cells in the presence of immunizing cells (secondary mixed leukocyte cultures [MLC]) as compared to that found in primary MLC (i.e., without previous allograft). This phenomenon appears after 24 h of culture and reaches its maximum at 48 h. Optimal increased histamine production is observed when MLC is performed with spleen cells removed from mice during rejection. This increased production of histamine during secondary MLC results from the action of a lymphokine: the histamine-producing cell stimulating factor (HCSF). This factor is released by T lymphocytes. Its production requires specific stimulation of the recipient lymphocytes because increase in histamine production during secondary MLC can be only observed when recipient cells are cultured with stimulating cells bearing at least one homology at K or D loci with immunizing cells. HCSF acts on a cell which is present in bone marrow, spleen, blood, and peritoneal cells but absent in thymus or lymph node cells. This target cell is found in the less-dense layer of a discontinuous Ficoll-gradient of bone marrow cells. HCSF is heat stable, destroyed by trypsin treatment, and has a molecular weight between 50,000 and 100,000. It acts on its target cells by increasing histidine decarboxylase activity
Dual mobility hip arthroplasty wear measurement: Experimental accuracy assessment using radiostereometric analysis (RSA)
SummaryIntroductionThe use of dual mobility cups is an effective method to prevent dislocations. However, the specific design of these implants can raise the suspicion of increased wear and subsequent periprosthetic osteolysis.HypothesisUsing radiostereometric analysis (RSA), migration of the femoral head inside the cup of a dual mobility implant can be defined to apprehend polyethylene wear rate.Study objectivesThe study aimed to establish the precision of RSA measurement of femoral head migration in the cup of a dual mobility implant, and its intra- and interobserver variability.Material and methodsA total hip prosthesis phantom was implanted and placed under weight loading conditions in a simulator. Model-based RSA measurement of implant penetration involved specially machined polyethylene liners with increasing concentric wear (no wear, then 0.25, 0.5 and 0.75mm). Three examiners, blinded to the level of wear, analyzed (10 times) the radiostereometric films of the four liners. There was one experienced, one trained, and one inexperienced examiner. Statistical analysis measured the accuracy, precision, and intra- and interobserver variability by calculating Root Mean Square Error (RMSE), Concordance Correlation Coefficient (CCC), Intra Class correlation Coefficient (ICC), and Bland-Altman plots.ResultsOur protocol, that used a simple geometric model rather than the manufacturer's CAD files, showed precision of 0.072mm and accuracy of 0.034mm, comparable with machining tolerances with low variability. Correlation between wear measurement and true value was excellent with a CCC of 0.9772. Intraobserver reproducibility was very good with an ICC of 0.9856, 0.9883 and 0.9842, respectively for examiners 1, 2 and 3. Interobserver reproducibility was excellent with a CCC of 0.9818 between examiners 2 and 1, and 0.9713 between examiners 3 and 1.DiscussionQuantification of wear is indispensable for the surveillance of dual mobility implants. This in vitro study validates our measurement method. Our results, and comparison with other studies using different measurement technologies (RSA, standard radiographs, Martell method) make model-based RSA the reference method for measuring the wear of total hip prostheses in vivo.Level of evidenceLevel 3. Prospective diagnostic study
Digestive microbiota changes during application of an effective, feed presentation based, mitigation option against Salmonella shedding in pigs
If some studies have attempted to mitigate the Salmonella spp. excretion in pigs by feed related interventions, none clearly demonstrated the impact of the presentation (mash or pellet and particular size). Thus this study aimed to determine if the modification of the pigs feed presentation alone can lower the Salmonella spp. excretion
Impact of mash feeding versus pellets on propionic/butyric acid levels and on total Escherichia coli load in the gastrointestinal tract of growing pigs
Feed characteristics may influence
the bacterial community composition and metabolic
activities in the pig gastrointestinal tract, known to be
associated with positive effects on the gut. Use of mash
feed is associated with reduced Salmonella excretion,
but little is known of its effect on the Escherichia coli
population or of the mechanism of action. Our objectives
were to assess the effect of feed texture combined
with feed particle size on VFA profiles and levels,
total E. coli count, and the presence of genes encoding
virulence factors of pathogenic E. coli strains in the
digestive tract along with their impact on pig performance
of fattening pigs. Pigs (n = 840) on a commercial
farm received mash or pellet diets of different particle
sizes during the fattening period. Caecal and colon contents
from 164 pigs were sampled at the slaughterhouse
for enumeration of E. coli by quantitative PCR (qPCR)
and for VFA quantification by capillary gas chromatography.
The yccT gene was used to enumerate total E.
coli. Improved pig performances associated with pellet
texture and a 500-μm size were observed. Caecal (P =
0.02) and colon (P < 0.01) propionic acid concentrations
were lower for pigs receiving pellet rather than
mash feed. Similarly, caecal (P = 0.01) and colon (P <
0.001) butyric acid concentrations were also lower for
pigs receiving pellet rather than mash feed, as determined
by capillary gas chromatography. Moreover,
caecal (P = 0.03) and colon (P < 0.001) butyric acid
concentrations were higher for pigs receiving a feed
with a 1,250-μm particle size rather than a 500-μm
particle size. On the other hand, total caecal and colon
E. coli levels were higher for pigs receiving pellet feed
than for those receiving mash feed. For total E. coli
enumeration, caecal (P < 0.01) and colon (P < 0.01)
yccT gene copies were higher for pigs receiving pellet
rather than mash feed. No effect of particle size on
fatty acid concentrations or on E. coli numbers was
observed. Virulence gene quantification revealed no
trend. Taken together, results showed that mash feed
is associated with lower growth performance but with
favorable intestinal changes linked to VFA levels and E.
coli reduction in the intestine
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