2,028 research outputs found
A critique of avian CHD-based molecular sexing protocols illustrated by a Z-chromosome polymorphism detected in auklets
The sexes of non-ratite birds can be determined routinely by PCR amplification of the CHD-Z and CHD-W genes.
CHD -based molecular sexing of four species of auklets revealed the presence of a polymorphism in the Z chromosome. No deviation from a 1:1 sex ratio was observed among the chicks, though the analyses were of limited power. Polymorphism in the CHD-Z
gene has not been reported previously in any bird, but if undetected it could lead to the incorrect assignment of sex. We discuss the potential difficulties caused by a
polymorphism such as that identified in auklets and the merits of alternative CHD -based sexing protocols and primers
Kinetics of Alkyl Lactate Formation from the Alcoholysis of Poly(Lactic Acid)
Alkyl lactates are green solvents that are successfully employed in several industries such as pharmaceutical, food and agricultural. They are considered prospective renewable substitutes for petroleum-derived solvents and the opportunity exists to obtain these valuable chemicals from the chemical recycling of waste poly(lactic acid). Alkyl lactates (ethyl lactate, propyl lactate and butyl lactate) were obtained from the catalysed alcoholysis reaction of poly(lactic acid) with the corresponding linear alcohol. Reactions were catalysed by a Zn complex synthesised from an ethylenediamine Schiff base. The reactions were studied in the 50â130 °C range depending on the alcohol, at autogenous pressure. Arrhenius temperature-dependent parameters (activation energies and pre-exponential factors) were estimated for the formation of the lactates. The activation energies (Ea1, Ea2 and Eaâ2) for alcoholysis in ethanol were 62.58, 55.61 and 54.11 kJ/mol, respectively. Alcoholysis proceeded fastest in ethanol in comparison to propanol and butanol and reasonable rates can be achieved in temperatures as low as 50 °C. This is a promising reaction that could be used to recycle end-of-life poly(lactic acid) and could help create a circular production economy
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Poor choices: the limits of competitive markets in the provision of essential services to low-income consumers
A major study of the problems faced by the poor in the market for seven essential services in the UK - energy, food, housing, water, telecoms, transport, and financial services. Together these represent 60% of spending by the poorest 30% of households
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Engineering work plan tank farm lightning mitigation system
This Engineering Work Plan defines the scope, function and design criteria, and installation activities that will be provided in support of the Tank Farm Lightning Mitigation System. The Tank Farm Lightning Mitigation System is comprised of two tasks, the light pole air terminal design and the tank riser bonding design. Air terminals, riser and riser flange bonding system will be designed and installed to mitigate the effect of lightning strikes in single shell tank farms with watchlist tanks
On the Representation Theory of an Algebra of Braids and Ties
We consider the algebra introduced by F. Aicardi and J.
Juyumaya as an abstraction of the Yokonuma-Hecke algebra. We construct a tensor
space representation for and show that this is faithful. We use
it to give a basis for and to classify its irreducible
representations.Comment: 24 pages. Final version. To appear in Journal of Algebraic
Combinatorics
Single nucleotide polymorphisms in the bovine leptin gene and their association with carcass and efficiency traits, and endocrine profiles, in female Angus cows
One hundred and fifty female Angus cattle were genotyped for the bovine leptin gene SNPs UASMS1, UASMS2, E2FB and E2JW. Net Feed Intake (NFI) Estimated Breeding Values (EBVs) and E2JW SNP data was also acquired from 169 Angus cattle that originated from Trangie Research Station, NSW, and were selected for a divergence in feed efficiency. The E2JW SNP was associated with NFI, NFI EBV and P8 fatness. The UASMS1 and UASMS2 SNPs were associated with circulating leptin concentrations. These particular associations have not been reported previously but similar associations have reported in North American studies. The inconsistent associations suggest that these SNPs are not good candidates for marker-assisted selection for NFI. Also, the investigation of associations with endocrine profiles that reflect body composition such as leptin, requires genotyping of a larger number of Australian cattle than was possible in this experiment
The Magnificent Seven: Magnetic fields and surface temperature distributions
Presently seven nearby radio-quiet isolated neutron stars discovered in ROSAT
data and characterized by thermal X-ray spectra are known. They exhibit very
similar properties and despite intensive searches their number remained
constant since 2001 which led to their name ``The Magnificent Seven''. Five of
the stars exhibit pulsations in their X-ray flux with periods in the range of
3.4 s to 11.4 s. XMM-Newton observations revealed broad absorption lines in the
X-ray spectra which are interpreted as cyclotron resonance absorption lines by
protons or heavy ions and / or atomic transitions shifted to X-ray energies by
strong magnetic fields of the order of 10^13 G. New XMM-Newton observations
indicate more complex X-ray spectra with multiple absorption lines. Pulse-phase
spectroscopy of the best studied pulsars RX J0720.4-3125 and RBS 1223 reveals
variations in derived emission temperature and absorption line depth with pulse
phase. Moreover, RX J0720.4-3125 shows long-term spectral changes which are
interpreted as due to free precession of the neutron star. Modeling of the
pulse profiles of RX J0720.4-3125 and RBS 1223 provides information about the
surface temperature distribution of the neutron stars indicating hot polar caps
which have different temperatures, different sizes and are probably not located
in antipodal positions.Comment: 10 pages, 8 figures, to appear in Astrophysics and Space Science, in
the proceedings of "Isolated Neutron Stars: from the Interior to the
Surface", edited by D. Page, R. Turolla and S. Zan
Structural And Magnetic Study Of Labacocu O5+ÎŽ
The structure and magnetic properties of the compound LaBaCuCo O5+ÎŽ have been studied for the non-stoichiometric oxygen concentration ÎŽâ0.6. The structure is pseudo-cubic with a tripled perovskite unit cell. The crystal structure was determined by a combined Rietveld fit to neutron and synchrotron x-ray powder diffraction data in the orthorhombic Pmmm space group, with cell parameters a=3.9223 (3) Ă
, b=3.9360 (3) Ă
, c=11.7073 (8) Ă
, and V=180.74 (2) Ă
3 (room temperature). Antiferromagnetic ordering of Cu and Co magnetic moments is observed below 205 (4) K. The magnetic structure with cell aM =2a, bM =2b, and cM =2c, could be described with the Shubnikov space group Fmm mâČ. The magnetic moments of both equivalent Cu/Co sites were determined at 50 and 170 K to be 0.83 (3) ÎŒB and 0.58 (3) ÎŒB, respectively, consistent with one unpaired electron per atom. The fit of the intensities to a simple mean field magnetic model appeared to be insufficient to account for the variation of moments at temperatures close to TN while a three dimensional Heisenberg model could improve the fit. Susceptibility measurements between 4 and 350 K also show irreversibility below 150 K. The local environments of Cu and Co were studied by extended x-ray absorption fine structure spectroscopy at both absorption edges. Cu atoms adopt an elongated octahedral or square-based pyramidal oxygen environment which suggests mainly the presence of Cu(II) in the structure. Co adopts different local environments, depending on the electronic and spin states. © 2005 The American Physical Society.7114Er-Rakho, L., Michel, C., Lacorre, P., Raveau, B., (1988) J. Solid State Chem., 73, p. 531. , JSSCBI 0022-4596 10.1016/0022-4596(88)90141-7Meyer, C., Hartmann-Boutron, F., Gros, Y., Strobel, P., (1990) Solid State Commun., 76, p. 163. , SSCOA4 0038-1098 10.1016/0038-1098(90)90535-JAtanassova, Y.K., Popov, V.N., Bogachev, G.G., Iliev, M.N., Mitros, C., Psycharis, V., Pissas, M., (1993) Phys. Rev. B, 47, p. 15201. , PRBMDO 0163-1829 10.1103/PhysRevB.47.15201MombrĂș, A.W., Christides, C., Lappas, A., Prassides, K., Pissas, M., Mitros, C., Niarchos, D., (1994) Inorg. Chem., 33, p. 1255. , INOCAJ. 0020-1669Caignaert, V., Mirebeau, I., Bouree, F., Nguyen, N., Ducouret, A., Greneche, J.M., Raveau, B., (1995) J. 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Calcium confusion--is the variability in calcium response by Sertoli cells to specific hormones meaningful or simply redundant?
When results of more than ten different studies on hormone-induced calcium
signals in Sertoli cells are taken together, a wide variety of responses
emerges. The reported changes range from increased concentrations, via no
response at all, to decreased calcium concentrations. Minor variations in
cell isolation techniques, culture conditions, or techniques for measuring
the intracellular calcium could explain some of these differences.
However, erratic variations in response are also observed within research
groups under very similar experimental conditions. Such 'negative'
findings are mainly reported orally and do not further penetrate the
scientific community. As hormone-dependent calcium responses evidently may
depend very much on the context of the cells, calcium transients would
appear to be unreliable bioassay principles with which to detect the
primary actions of FSH and effectors such as androgens on Sertoli cells. A
more important biological question is whether these sometimes opposed
calcium transients are connected with a particular cellular response. To
date there is no evidence for such a tight coupling in Sertoli cells,
implying that, at least under in vitro conditions, calcium signals might
even be redundant altogether. Such calcium variability is probably not
unique to Sertoli cells, and the aim of this commentary is to promote an
open debate that may help to transform the current state of 'calcium
confusion' into a better understanding of the intracellular calcium
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