2,081 research outputs found
An experimental study of the cryoentrainment pump Progress report
Cryoentrainment pump using liquid nitrogen and helium as cooling mediu
A study of the relative effectiveness and cost of computerized information retrieval in the interactive mode
Results of a number of experiments to illuminate the relative effectiveness and costs of computerized information retrieval in the interactive mode are reported. It was found that for equal time spent in preparing the search strategy, the batch and interactive modes gave approximately equal recall and relevance. The interactive mode however encourages the searcher to devote more time to the task and therefore usually yields improved output. Engineering costs as a result are higher in this mode. Estimates of associated hardware costs also indicate that operation in this mode is more expensive. Skilled RECON users like the rapid feedback and additional features offered by this mode if they are not constrained by considerations of cost
Enhanced moments of Eu in single crystals of the metallic helical antiferromagnet EuCo2 yAs2
The compound EuCo{2-y}As2 with the tetragonal ThCr2Si2 structure is known to
contain Eu{+2} ions with spin S = 7/2 that order below a temperature TN = 47 K
into an antiferromagnetic (AFM) proper helical structure with the ordered
moments aligned in the tetragonal ab plane, perpendicular to the helix axis
along the c axis, with no contribution from the Co atoms. Here we carry out a
detailed investigation of the properties of single crystals. Enhanced ordered
and effective moments of the Eu spins are found in most of our crystals.
Electronic structure calculations indicate that the enhanced moments arise from
polarization of the d bands, as occurs in ferromagnetic Gd metal. Electrical
resistivity measurements indicate metallic behavior. The low-field in-plane
magnetic susceptibilities chi{ab}(T < TN) for several crystals are reported
that are fitted well by unified molecular field theory (MFT), and the Eu-Eu
exchange interactions Jij are extracted from the fits. High-field magnetization
M data for magnetic fields H||ab reveal what appears to be a first-order
spin-flop transition followed at higher field by a second-order metamagnetic
transition of unknown origin, and then by another second-order transition to
the paramagnetic (PM) state. For H||c, the magnetization shows only a
second-order transition from the canted AFM to the PM state, as expected. The
critical fields for the AFM to PM transition are in approximate agreement with
the predictions of MFT. Heat capacity Cp measurements in zero and high H are
reported. Phase diagrams for H||c and H||ab versus T are constructed from the
high-field M(H,T) and Cp(H,T) measurements. The magnetic part Cmag(T, H = 0) of
Cp(T, H = 0) is extracted and is fitted rather well below TN by MFT, although
dynamic short-range AFM order is apparent in Cmag(T) up to about 70 K, where
the molar entropy attains its high-T limit of R ln8.Comment: 29 pages, 30 figures including 62 subfigures, 8 tables, 84 reference
Early adolescent disclosure and parental knowledge regarding online activities: Social anxiety and parental rule-setting as moderators
Early adolescents spend a lot of time online, yet little is currently known about the links between parental rule-setting, adolescent disclosure about online activities, and whether social anxiety may interfere with these processes. Using a longitudinal sample of 526 adolescents (269 girls; Mage = 14.00) and their parents (79% mothers, Mage = 43.66), the results from the current study showed low correspondence between parental knowledge, adolescent disclosure, as well as parents’ and adolescents’ ratings of parental legitimacy to set boundaries about online activities. High social anxiety interacted with high adolescent-rated parental rule-setting in predicting the least disclosure about chatting with strangers and posting online content over time. Also, high social anxiety interacted with low parent-rated control to predict more adolescent disclosure about chatting with strangers and money spent online over time. Thus, social anxiety and parental rule-setting moderated the links between disclosure and knowledge for some early adolescent online activities. Our results conflict with the value typically placed on parental rule-setting in online contexts, at least for socially anxious adolescents
Magnetocardiography with a modular spin-exchange relaxation free atomic magnetometer array
We present a portable four-channel atomic magnetometer array operating in the
spin exchange relaxation-free regime. The magnetometer array has several design
features intended to maximize its suitability for biomagnetic measurement,
specifically foetal magnetocardiography, such as a compact modular design, and
fibre coupled lasers. The modular design allows the independent positioning and
orientation of each magnetometer, in principle allowing for non-planar array
geometries. Using this array in a magnetically shielded room, we acquire adult
magnetocadiograms. These measurements were taken with a 6-11 fT Hz^(-1/2)
single-channel baseline sensitivity that is consistent with the independently
measured noise level of the magnetically shielded room.Comment: 15 pages, 5 figure
Human Galectins Induce Conversion of Dermal Fibroblasts into Myofibroblasts and Production of Extracellular Matrix: Potential Application in Tissue Engineering and Wound Repair
Members of the galectin family of endogenous lectins are potent adhesion/growth-regulatory effectors. Their multi-functionality opens possibilities for their use in bioapplications. We studied whether human galectins induce the conversion of human dermal fibroblasts into myofibroblasts (MFBs) and the production of a bioactive extracellular matrix scaffold is suitable for cell culture. Testing a panel of galectins of all three subgroups, including natural and engineered variants, we detected activity for the proto-type galectin-1 and galectin-7, the chimera-type galectin-3 and the tandem-repeat-type galectin-4. The activity of galectin-1 required the integrity of the carbohydrate recognition domain. It was independent of the presence of TGF-beta 1, but it yielded an additive effect. The resulting MFBs, relevant, for example, for tumor progression, generated a matrix scaffold rich in fibronectin and galectin-1 that supported keratinocyte culture without feeder cells. Of note, keratinocytes cultured on this substratum presented a stem-like cell phenotype with small size and keratin-19 expression. In vivo in rats, galectin-1 had a positive effect on skin wound closure 21 days after surgery. In conclusion, we describe the differential potential of certain human galectins to induce the conversion of dermal fibroblasts into MFBs and the generation of a bioactive cell culture substratum. Copyright (C) 2011 S. Karger AG, Base
\u3ci\u3ePhilonthus furvus\u3c/i\u3e Nordmann, 1837 and its allies in Mexico and Central America (Coleoptera: Staphylinidae)
The Mexican and Central American species associated with Philonthus firvus Nordmann, 1837 are reviewed. Nine species are treated, two of them, P. oenotrus and P. melampus, both from Mexico, are described as new. Philonthus flohri Sharp, 1876 is removed from synonymy with P. furvus. All species are described and illustrated, and a key is added to aid in their identification. All available records from Mexico and Central America, and biological data for the species are provided. Lectotypes are designated for: P. flohri Sharp, 1876; P. sallaei Sharp, 1885; P. fissilis Sharp, 1885; P. nigerrimus Erichson, 1840
Fourth West Australian random sample egg laying test : 1960-1961
TO help improve the quality of laying stock for poultry farmers in Western Australia the Poultry Branch of the Department of Agriculture conducts annual random sample egg laying tests.
The tests reveal good and bad points in the laying strains available, and their results are a valuable guide to breeders.
Most of the chickens sold in Western Australia are now bred by hatcherymen who participate in the Random Sample Tests
Fifth West Australian random sample egg laying test : 1961-1962 : progressive laying report to April 29, 1962
FIFTH RANDOM SAMPLE LAYING TEST, 1961-62 Progressive Report to April 29th, 1962 (18 Weeks
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