KINETIC COMPONENTS OF ROPE SKIPPING: A PILOT STUDY

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A multisite microcanonical updating method

We have made a study of several update algorithms using the XY model. We find that sequential local overrelaxation is not ergodic at the scale of typical Monte Carlo simulation time. We have introduced a new multisite microcanonical update method, which yields results compatible with those of random overrelaxation and the microcanonical demon algorithm, which are very much slower, all being incompatible with the sequential overrelaxation results.Comment: 13 pages, 4 figure

Preeclampsia is associated with compromized maternal synthesis of long chain polyunsaturated fatty acids leading to offspring deficiency

Obesity and excessive lipolysis are implicated in preeclampsia (PE). Intrauterine growth restriction is associated with low maternal body mass index and decreased lipolysis. Our aim was to assess how maternal and offspring fatty acid metabolism is altered in mothers in the third trimester of pregnancy with PE (n=62) or intrauterine growth restriction (n=23) compared with healthy pregnancies (n=164). Markers of lipid metabolism and erythrocyte fatty acid concentrations were measured. Maternal adipose tissue fatty acid composition and mRNA expression of adipose tissue fatty acid–metabolizing enzymes and placental fatty acid transporters were compared. Mothers with PE had higher plasma triglyceride (21%, P<0.001) and nonesterified fatty acid (50%, P<0.001) concentrations than controls. Concentrations of major n−6 and n−3 long-chain polyunsaturated fatty acids in erythrocytes were 23% to 60% lower (all P<0.005) in PE and intrauterine growth restriction mothers and offspring compared with controls. Subcutaneous adipose tissue Δ−5 and Δ−6 desaturase and very long-chain fatty acid elongase mRNA expression was lower in PE than controls (respectively, mean [SD] control 3.38 [2.96] versus PE 1.83 [1.91], P=0.030; 3.33 [2.25] versus 1.03 [0.96], P<0.001; 0.40 [0.81] versus 0.00 [0.00], P=0.038 expression relative to control gene [square root]). Low maternal and fetal long-chain polyunsaturated fatty acid concentrations in PE may be the result of decreased maternal synthesis

Mob Rulers And Part-time Cleaners: Two Reef Fish Associations At The Isolated Ascension Island

Isolated oceanic islands may give rise not only to new and endemic species, but also to unique behaviours and species interactions. Multi-species fish interactions, such as cleaning, following, mob-feeding and others are understudied in these ecosystems. Here we present qualitative and quantitative observations on cleaning and mob-feeding reef fish associations at the isolated Ascension Island, South Atlantic Ocean. Cleaning interactions were dominated by juveniles of the facultative fish cleaners Bodianus insularis and Pomacanthus paru, with lesser contributions of Chaetodon sanctaehelenae, Thalassoma ascensionis and the cleaner shrimp Lysmata grabhami. Two types of feeding mobs were consistently identified: less mobile mobs led by the surgeonfish Acanthurus bahianus and A. coeruleus and the more mobile mobs led by the African sergeant Abudefduf hoefleri. This is the first record of A. hoefleri from outside of the Eastern Atlantic and also the first report of this species displaying mob-feeding behaviour. The principal follower of both mob types was the extremely abundant Melichthys niger, but the main aggressor differed: Stegastes lubbocki, a highly territorial herbivore, was the main aggressor of Acanthurus mobs; and Chromis multilineata a territorial fish while engaged in egg parental care, was the principal aggressor towards Abudefduf mobs. Our study enhances the scarce information on reef fish feeding associations at the isolated Ascension Island and at oceanic islands in the Atlantic in general. Copyright © Marine Biological Association of the United Kingdom 201611

SCIENCECRAFT

The technological capabilities are now at hand to design an integrated system that combine science instruments, spacecraft and propulsion elements into a single system. The authors have called this a Sciencecraft since it is intended to provide automatic scientific observations of planetary and astrophysical objects. Integration of function allows lower mass and cost and supports a short development cycle. A specific science mission is described in this paper, a flyby of Neptune, Triton and an object in the Kuiper belt. The SCIENCECRAFT system is described. It has electric propulsion and is capable of measuring the surface constituents and morphology of the objects visited and characterizing their atmospheres both in emission and absorption (against the sun). Miniature fields and particles experiments are incorporated that will provide interplanetary information together with details of the magnetic and electric attributes of each object. The SCIENCECRAFT is Delta launched and has a flight time to the Kuiper belt of 7 years. The design is such that the craft functions in a largely autonomous mode to provide low cost mission operations

Shadowing in photo-production : role of in-medium hadrons

We study the effects of in-medium hadronic properties on shadowing in photon-nucleus interactions in Glauber model as well as in the multiple scattering approach. A reasonable agreement with the experimental data is obtained in a scenario of downward spectral shift of the hadrons. Shadowing is found to be insensitive to the broadening of the spectral functions. An impact parameter dependent analysis of shadowing might shed more light on the role of in-medium properties of hadrons.Comment: Title modified; version to appear in PRC, Rapid Communication

The influence of hypoxia and energy depletion on the response of endothelial cells to the vascular disrupting agent combretastatin A-4-phosphate

Combretastatin A-4 phosphate (CA4P) is a microtubule-disrupting tumour-selective vascular disrupting agent (VDA). CA4P activates the actin-regulating RhoA-GTPase/ ROCK pathway, which is required for full vascular disruption. While hypoxia renders tumours resistant to many conventional therapies, little is known about its influence on VDA activity. Here, we found that active RhoA and ROCK effector phospho-myosin light chain (pMLC) were downregulated in endothelial cells by severe hypoxia. CA4P failed to activate RhoA/ROCK/pMLC but its activity was restored upon reoxygenation. Hypoxia also inhibited CA4P-mediated actinomyosin contractility, VE-cadherin junction disruption and permeability rise. Glucose withdrawal downregulated pMLC, and coupled with hypoxia, reduced pMLC faster and more profoundly than hypoxia alone. Concurrent inhibition of glycolysis (2-deoxy-D-glucose, 2DG) and mitochondrial respiration (rotenone) caused profound actin filament loss, blocked RhoA/ROCK signalling and rendered microtubules CA4P-resistant. Withdrawal of the metabolism inhibitors restored the cytoskeleton and CA4P activity. The AMP-activated kinase AMPK was investigated as a potential mediator of pMLC downregulation. Pharmacological AMPK activators that generate AMP, unlike allosteric activators, downregulated pMLC but only when combined with 2DG and/or rotenone. Altogether, our results suggest that Rho/ROCK and actinomyosin contractility are regulated by AMP/ATP levels independently of AMPK, and point to hypoxia/energy depletion as potential modifiers of CA4P response

Finite size effects on measures of critical exponents in d=3 O(N) models

We study the critical properties of three-dimensional O(N) models, for N=2,3,4. Parameterizing the leading corrections-to-scaling for the $\eta$ exponent, we obtain a reliable infinite volume extrapolation, incompatible with previous Monte Carlo values, but in agreement with $\epsilon$-expansions. We also measure the critical exponent related with the tensorial magnetization as well as the $\nu$ exponents and critical couplings.Comment: 12 pages, 2 postscript figure

Some mechanisms of "spontaneous" polarization of superfluid He-4

Previously, a quantum "tidal" mechanism of polarization of the atoms of He-II was proposed, according to which, as a result of interatomic interaction, each atom of He-II acquires small fluctuating dipole and multipole moments, oriented chaotically on the average. In this work, we show that, in the presence of a temperature or density gradient in He-II, the originally chaotically oriented tidal dipole moments of the atoms become partially ordered, which results in volume polarization of He-II. It is found that the gravitational field of the Earth induces electric induction U =10(-7)V in He-II (for vessel dimensions of the order of 10 cm). We study also the connection of polarization and acceleration, and discuss a possible nature of the electric signal dU = kdT/2e observed by A.S. Rybalko in experiments with second sound.Comment: 13 pages; the calculation is extended and refined; v4: reconstructio