2,985 research outputs found
Saturated hydrocarbon polymeric binder for advanced solid propellant and hybrid solid grains Quarterly report no. 3, 1 May - 31 Jul. 1966
Saturated hydrocarbon polymeric binder for advanced solid propellant and hybrid solid grain
Saturated hydrocarbon polymeric binder for advanced solid propellant and hybrid solid grains Quarterly report no. 2, 1 Feb. - 30 Apr. 1966
Synthesis and analysis of ethylene-neohexene copolymers with other non ketene-imine group free radicals for solid and hybrid grain propellant saturated hydrocarbon binder progra
Ethnicity and academic performance in UK trained doctors and medical students: systematic review and meta-analysis
Objective To determine whether the ethnicity of UK trained doctors and medical students is related to their academic performance
2D Potts Model Correlation Lengths: Numerical Evidence for at
We have studied spin-spin correlation functions in the ordered phase of the
two-dimensional -state Potts model with , 15, and 20 at the
first-order transition point . Through extensive Monte Carlo
simulations we obtain strong numerical evidence that the correlation length in
the ordered phase agrees with the exactly known and recently numerically
confirmed correlation length in the disordered phase: . As a byproduct we find the energy moments in the ordered phase
at in very good agreement with a recent large -expansion.Comment: 11 pages, PostScript. To appear in Europhys. Lett. (September 1995).
See also http://www.cond-mat.physik.uni-mainz.de/~janke/doc/home_janke.htm
Population connectivity of an overexploited coastal fish, Argyrosomus coronus (Sciaenidae), in an ocean-warming hotspot
The West Coast dusky kob Argyrosomus coronus is a commercially exploited fish with a distribution confined to the Angola–Benguela Frontal Zone (ABFZ) of the southeastern Atlantic Ocean. A previous study revealed that during a recent period of local warming the species extended its distribution into Namibian waters, where it hybridised with the resident and congeneric Argyrosomus inodorus. Environmental changes are a major threat to marine biodiversity and when combined with overfishing have the potential to accelerate the decline of species. However, little is known regarding the evolutionary history and population structure of A. coronus across the ABFZ. We investigated genetic diversity, population structure and historical demographic changes using mtDNA control region sequences and genotypes at six nuclear microsatellite loci, from 180 individuals. A single, genetically homogeneous population was indicated across the distributional range of A. coronus (ϕST = 0.041, FST = 0.000, D = 0.000; p > 0.05). These findings imply that the oceanographic features within the ABFZ do not appear to significantly influence population connectivity in A. coronus, which simplifies management of the species. However, reconstruction of the demographic history points to a close link between the evolutionary history of A. coronus and the environmental characteristics of the ABFZ. This outcome suggests the species’ vulnerability to the rapid environmental changes being observed across this region, and highlights a pressing need for transboundary management to mitigate the impacts of climate change in this global hotspot of seawater temperature changes.Keywords: Angola–Benguela Frontal Zone, climate change, demographic history, marine fisheries, molecular ecology, population structur
Hydrocarbon polymeric binder for advanced solid propellant
Various experimental factors were examined to determine the source of difficulty in an isoprene polymerization in the 5-gallon reactor which gave a non-uniform product of low functionality. It was concluded that process improvements relating to initiator and monomer purity were desirable, but that the main difficulty was in the initiator feed system. A new pumping system was installed and an analog simulation of the reactor, feed system and initiator decomposition kinetics was devised which permits the selection of initial initiator concentrations and feed rates to use to give a nearly uniform initiator concentration throughout a polymerization run. An isoprene polymerization was run in which the process improvements were implemented
Testing potential mechanisms underlying test-potentiated new learning
An emerging body of studies demonstrates that practicing retrieval of studied information, by comparison with restudying or no treatment, can facilitate subsequent learning and retrieval of new information, a phenomenon termed the forward testing effect (FTE) or test-potentiated new learning. Several theoretical explanations have been proposed to account for the FTE. A release-from-PI theory proposes that interpolated testing induces context changes and enhances event segregation, which in turn protect new learning from proactive interference (PI). A strategy-change view hypothesizes that prior tests teach learners to adopt more effective/elaborative learning and retrieval strategies in subsequent study and test phases. Finally, a reset-of-encoding account proposes that interim testing on studied information reduces memory load, resets the subsequent encoding process, and enhances encoding of new information. The current study recruited a large sample (over 1,000 participants) and employed a multilist learning task and mediation analyses to test these theories. The results suggest that prior list intrusions (an index of PI) significantly mediated the FTE, supporting the release-from-PI theory. In addition, interim testing enhanced strategic processing of temporal information during new learning (reflected by increased clustering), and temporal clustering significantly mediated the FTE, supporting a role for strategy-change in the FTE. Lastly, a variety of indices were constructed to represent the benefit of reset-of-encoding, but none of them provided evidence supporting the reset-of-encoding view. The results shed new light on the complex mechanisms underlying the forward benefits of testing. (PsycInfo Database Record (c) 2021 APA, all rights reserved
- …