1,848 research outputs found
A Review and Interspecific Comparison of Nocturnal and Cathemeral Strepsirhine Primate Olfactory Behavioural Ecology
This paper provides a comparative review of the known patterns of olfactory behavioural ecology among the nocturnal strepsirhine primates and the cathemeral lemurid genus Eulemur. Endemic to Madagascar, all Eulemur species exhibit both diurnality and nocturnality (i.e., cathemerality), and are gregarious, making them an interesting group of taxa to compare with the nocturnal strepsirhines. This paper represents the first comparative review of patterns of olfactory communication among the nocturnal strepsirhines and the cathemeral Eulemur species. Inductive assessment of these comparative data indicates that olfactory communication serves multiple functions in both groups, including individual recognition, sex recognition, indication of social dominance, and coordination of mating behaviour. However, the urine-washing behaviour characteristic of many nocturnal strepsirhines has no clear homologue among Eulemur species (although the latter may use urine droplets in scent marking). Despite sparse and scattered comparative data, it appears that Eulemur species exhibit different olfactory communication patterns that are associated with differing social organizations in this genus
Predation and cathemerality. Comparing the impact of predators on the activity patterns of lemurids and ceboids.
The removal, or absence, of predatory species could be a contributing proximate factor to the rise of primate cathemerality. But predators themselves can also be cathemeral, so cathemerality could well be an evolutionary stable strategy. From a comparative perspective, it appears that the effect of predatory species cannot provide a unitary explanation for cathemerality. Varying distributions and population densities of predators, especially raptors, may be key factors in owl monkey (Aotus) cathemerality, but temperature and lunar cycle variation have also been implicated. In Madagascar, while raptors are potential predators of lemur species, the cathemerality of Eulemur species coincides with that of the fossa (Cryptoprocta ferox), a major predatory threat to lemurs. Thus, lemurid cathemerality may be more parsimoniously explained as an evolutionary stable strategy
Υ and Υ′ leptonic widths, abμ, and mb from full lattice QCD
We determine the decay rate to leptons of the ground-state ϒ meson and its first radial excitation in lattice
QCD for the first time. We use radiatively improved nonrelativistic QCD for the b quarks and include u, d,
s and c quarks in the sea with u=d masses down to their physical values. We find Γðϒ → eþe−Þ ¼
1.19ð11Þ keV and Γðϒ0 → eþe−Þ ¼ 0.69ð9Þ keV, both in good agreement with experimental results. The
decay constants we obtain are included in a summary plot of meson decay constants from lattice QCD
given in the Conclusions. We also test time moments of the vector current-current correlator against values
determined from the b-quark contribution to σðeþe− → hadronsÞ and calculate the b-quark piece of the
hadronic vacuum polarization contribution to the anomalous magnetic moment of the muon,
ab
μ ¼ 0.271ð37Þ × 10−10. Finally we determine the b-quark mass, obtaining in the MS scheme, ¯
m¯ bðm¯ b; nf ¼ 5Þ ¼ 4.196ð23Þ GeV, the most accurate result from lattice QCD to date
Ion-channel-like behavior in lipid bilayer membranes at the melting transition
It is well known that at the gel-liquid phase transition temperature a lipid
bilayer membrane exhibits an increased ion permeability. We analyze the
quantized currents in which the increased permeability presents itself. The
open time histogram shows a "-3/2" power law which implies an open-closed
transition rate that decreases like as time evolves. We
propose a "pore freezing" model to explain the observations. We discuss how
this model also leads to the noise that is commonly observed in
currents across biological and artificial membranes.Comment: 5 pages, 4 figure
B-meson decay constants: a more complete picture from full lattice QCD
We extend the picture of -meson decay constants obtained in lattice QCD
beyond those of the , and to give the first full lattice QCD
results for the , and . We use improved NonRelativistic QCD
for the valence quark and the Highly Improved Staggered Quark (HISQ) action
for the lighter quarks on gluon field configurations that include the effect of
, and quarks in the sea with quark masses going down to
physical values. For the ratio of vector to pseudoscalar decay constants, we
find = 0.941(26), = 0.953(23) (both
less than 1.0) and = 0.988(27). Taking correlated
uncertainties into account we see clear indications that the ratio increases as
the mass of the lighter quark increases. We compare our results to those using
the HISQ formalism for all quarks and find good agreement both on decay
constant values when the heaviest quark is a and on the dependence on the
mass of the heaviest quark in the region of the . Finally, we give an
overview plot of decay constants for gold-plated mesons, the most complete
picture of these hadronic parameters to date.Comment: 20 pages, 9 figures. Minor updates to the discussion in several
places and some additional reference
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Inducing hardening and healability in poly(ethylene-co-acrylic acid) via blending with complementary low molecular weight additives
The design and synthesis of low molecular weight additives based on self-assembling nitroarylurea units, and their compatibility with poly(ethylene-co-acrylic acid) copolymers are reported. The self-assembly properties of the low molecular weight additives have been demonstrated in a series of gelation studies. Upon blending at low percentage weights (≤ 5%) with poly(ethylene-co-acrylic acid) the additives were capable of increasing the stress and strain to failure when compared to the parent copolymer. By varying the percentage weight of the additive as well as the type of additive the mechanical properties of poly(ethylene-co-acrylic acid) could be tailored. Finally, the healability characteristics of the blends were improved when compared to the original polymer via the introduction of a supramolecular ‘network within a network’
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Synthesis and analysis of a healable, poly(propylene glycol)-based supramolecular network
An investigation into healable supramolecular networks based upon branched poly(propylene) (PPG) oligomers that feature nitroarylurea chain ends is reported. A one-pot reaction utilising bis(toluene-1,4-diisocyanate)-terminated poly(propyleneglycol) (Mn ~ 2300), a nitroarylurea recognition motif, and tris(2-aminoethyl)amine was used to synthesise several branched PPG-based oligomers. The degree of oligomerization/branching was systematically varied by changing the stoichiometry of the starting materials in this one-pot reaction. The branched oligomers thus generated self-assemble into supramolecular networks, aided by association of the nitroarylurea end groups, and from this study a material that is capable of healing at ambient temperatures was realised. The healable supramolecular material formed from these studies exhibited effective autonomous healing (80% with respect to ultimate stress) up to 6 weeks after defect formation. Furthermore, elastic recovery was observed (80% with respect to yield stress) over a period of 24 hours after the samples were elongated beyond the region of uniform strain (50%)
Entropy Production of Brownian Macromolecules with Inertia
We investigate the nonequilibrium steady-state thermodynamics of single
Brownian macromolecules with inertia under feedback control in isothermal
ambient fluid. With the control being represented by a velocity-dependent
external force, we find such open systems can have a negative entropy
production rate and we develop a mesoscopic theory consistent with the second
law. We propose an equilibrium condition and define a class of external forces,
which includes a transverse Lorentz force, leading to equilibrium.Comment: 10 pages, 1 figur
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