4,350 research outputs found
Transfer molding of PMR-15 polyimide resin
Transfer molding is an economically viable method of producing small shapes of PMR-15 polyimide. It is shown that with regard to flexural, compressive, and tribological properties transfer-molded PMR-15 polyimide is essentially equivalent to PMR-15 polyimide produced by the more common method of compression molding. Minor variations in anisotropy are predictable effects of molding design and secondary finishing operations
Strategies for stimulating poverty-alleviating growth in the rural nonfarm economy in developing countries:
"The rural nonfarm economy (RNFE) accounts for roughly 25 percent of full-time rural employment and 35-40 percent of rural incomes across the developing world. This diverse collection of seasonal trading, household-based and large-scale agroprocessing, manufacturing and service activities plays a crucial role in sustaining rural populations, in servicing a growing and modern agriculture, and in supplying local consumer goods and services. In areas where landlessness prevails, rural nonfarm activity offers important economic alternatives for the rural poor....Three key groups currently intervene in the rural nonfarm economy: large private enterprises, non-profit promotional agencies and governments. Large modern corporations take investment, procurement and marketing decisions that powerfully shape opportunities in the rural nonfarm economy throughout much of the Third World...." The authors put forth three basic principles for policy makers who want to ensure equitable growth of the RNFE : (1) Identify key engines of regional growth; (2) Focus on subsector-specific supply chains; and (3) Build flexible institutional coalitions. They conclude that "a prosperous rural nonfarm economy can contribute to both aggregate economic growth and improved welfare of the rural poor." from Executive Summary.Poverty alleviation Developing countries., Rural population., Employment, Non-agricultural Rural areas., Manufacturing industries., Service industries.,
The Source of Three-minute Magneto-acoustic Oscillations in Coronal Fans
We use images of high spatial, spectral and temporal resolution, obtained
using both ground- and space-based instrumentation, to investigate the coupling
between wave phenomena observed at numerous heights in the solar atmosphere.
Intensity oscillations of 3 minutes are observed to encompass photospheric
umbral dot structures, with power at least three orders-of-magnitude higher
than the surrounding umbra. Simultaneous chromospheric velocity and intensity
time series reveal an 87 \pm 8 degree out-of-phase behavior, implying the
presence of standing modes created as a result of partial wave reflection at
the transition region boundary. An average blue-shifted Doppler velocity of
~1.5 km/s, in addition to a time lag between photospheric and chromospheric
oscillatory phenomena, confirms the presence of upwardly-propagating slow-mode
waves in the lower solar atmosphere. Propagating oscillations in EUV intensity
are detected in simultaneous coronal fan structures, with a periodicity of 172
\pm 17 s and a propagation velocity of 45 \pm 7 km/s. Numerical simulations
reveal that the damping of the magneto-acoustic wave trains is dominated by
thermal conduction. The coronal fans are seen to anchor into the photosphere in
locations where large-amplitude umbral dot oscillations manifest. Derived
kinetic temperature and emission measure time-series display prominent
out-of-phase characteristics, and when combined with the previously established
sub-sonic wave speeds, we conclude that the observed EUV waves are the coronal
counterparts of the upwardly-propagating magneto-acoustic slow-modes detected
in the lower solar atmosphere. Thus, for the first time, we reveal how the
propagation of 3 minute magneto-acoustic waves in solar coronal structures is a
direct result of amplitude enhancements occurring in photospheric umbral dots.Comment: Accepted into ApJ (13 pages and 10 figures
Risk factors for race-day fatality in flat racing Thoroughbreds in Great Britain (2000 to 2013)
A key focus of the racing industry is to reduce the number of race-day events where horses die suddenly or are euthanased due to catastrophic injury. The objective of this study was therefore to determine risk factors for race-day fatalities in Thoroughbred racehorses, using a cohort of all horses participating in flat racing in Great Britain between 2000 and 2013. Horse-, race- and course-level data were collected and combined with all race-day fatalities, recorded by racecourse veterinarians in a central database. Associations between exposure variables and fatality were assessed using logistic regression analyses for (1) all starts in the dataset and (2) starts made on turf surfaces only. There were 806,764 starts in total, of which 548,571 were on turf surfaces. A total of 610 fatalities were recorded; 377 (61.8%) on turf. In both regression models, increased firmness of the going, increasing racing distance, increasing average horse performance, first year of racing and wearing eye cover for the first time all increased the odds of fatality. Generally, the odds of fatality also increased with increasing horse age whereas increasing number of previous starts reduced fatality odds. In the ‘all starts’ model, horses racing in an auction race were at 1.46 (95% confidence interval (CI) 1.06–2.01) times the odds of fatality compared with horses not racing in this race type. In the turf starts model, horses racing in Group 1 races were at 3.19 (95% CI 1.71–5.93) times the odds of fatality compared with horses not racing in this race type. Identification of novel risk factors including wearing eye cover and race type will help to inform strategies to further reduce the rate of fatality in flat racing horses, enhancing horse and jockey welfare and safety
Increased expression of programmed death ligand 1 (PD-L1) in human pituitary tumors
PURPOSE: Subsets of pituitary tumors exhibit an aggressive clinical courses and recur despite surgery, radiation, and chemotherapy. Because modulation of the immune response through inhibition of T-cell checkpoints has led to durable clinical responses in multiple malignancies, we explored whether pituitary adenomas express immune-related biomarkers that could suggest suitability for immunotherapy. Specifically, programmed death ligand 1 (PD-L1) has emerged as a potential biomarker whose expression may portend more favorable responses to immune checkpoint blockade therapies. We thus investigated the expression of PD-L1 in pituitary adenomas. METHODS: PD-L1 RNA and protein expression were evaluated in 48 pituitary tumors, including functioning and non-functioning adenomas as well as atypical and recurrent tumors. Tumor infiltrating lymphocyte populations were also assessed by immunohistochemistry. RESULTS: Pituitary tumors express variable levels of PD-L1 transcript and protein. PD-L1 RNA and protein expression were significantly increased in functioning (growth hormone and prolactin-expressing) pituitary adenomas compared to non-functioning (null cell and silent gonadotroph) adenomas. Moreover, primary pituitary adenomas harbored higher levels of PD-L1 mRNA compared to recurrent tumors. Tumor infiltrating lymphocytes were observed in all pituitary tumors and were positively correlated with increased PD-L1 expression, particularly in the functional subtypes. CONCLUSIONS: Human pituitary adenomas harbor PD-L1 across subtypes, with significantly higher expression in functioning adenomas compared to non-functioning adenomas. This expression is accompanied by the presence of tumor infiltrating lymphocytes. These findings suggest the existence of an immune response to pituitary tumors and raise the possibility of considering checkpoint blockade immunotherapy in cases refractory to conventional management
Reversible melting and equilibrium phase formation of (Bi,Pb)2Sr2Ca2Cu3O10+d
The decomposition and the reformation of the (Bi,Pb)2Sr2Ca2Cu3O10+d
(?Bi,Pb(2223)?) phase have been investigated in-situ by means of
High-Temperature Neutron Diffraction, both in sintered bulk samples and in
Ag-sheathed monofilamentary tapes. Several decomposition experiments were
performed at various temperatures and under various annealing atmospheres,
under flowing gas as well as in sealed tubes, in order to study the appropriate
conditions for Bi,Pb(2223) formation from the melt. The Bi,Pb(2223) phase was
found to melt incongruently into (Ca,Sr)2CuO3, (Sr,Ca)14Cu24O41 and a
Pb,Bi-rich liquid phase. Phase reformation after melting was successfully
obtained both in bulk samples and Ag-sheathed tapes. The possibility of
crystallising the Bi,Pb(2223) phase from the melt was found to be extremely
sensitive to the temperature and strongly dependent on the Pb losses. The study
of the mass losses due to Pb evaporation was complemented by thermogravimetric
analysis which proved that Pb losses are responsible for moving away from
equilibrium and therefore hinder the reformation of the Bi,Pb(2223) phase from
the melt. Thanks to the full pattern profile refinement, a quantitative phase
analysis was carried out as a function of time and temperature and the role of
the secondary phases was investigated. Lattice distortions and/or transitions
were found to occur at high temperature in Bi,Pb(2223), Bi,Pb(2212),
(Ca,Sr)2CuO3 and (Sr,Ca)14Cu24O41, due to cation diffusion and stoichiometry
changes. The results indicate that it is possible to form the Bi,Pb(2223) phase
from a liquid close to equilibrium conditions, like Bi(2212) and Bi(2201), and
open new unexplored perspectives for high-quality Ag-sheathed Bi,Pb(2223) tape
processing.Comment: 45 pages (including references,figures and captions), 13 figures
Submitted to Supercond. Sci. Techno
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