4,665 research outputs found
A measure of data collapse for scaling
No full textData collapse is a way of establishing scaling and extracting associated exponents in problems showing self-similar or self-affine characteristics as, for example, in equilibrium or non-equilibrium phase transitions, in critical phases, in dynamics of complex systems and many others. We propose a measure to quantify the nature of data collapse. Via a minimization of this measure, the exponents and their error-bars can be obtained. The procedure is illustrated by considering finite-size-scaling near phase transitions and quite strikingly recovering the exact exponents
Helicase on DNA: a phase coexistence based mechanism
No full textWe propose a phase coexistence based mechanism for activity of helicases, ubiquitous enzymes that unwind double stranded DNA. The helicase-DNA complex constitutes a fixed-stretch ensemble that entails the coexistence of domains of zipped and unzipped phases of DNA, separated by a domain wall. The motor action of the helicase leads to a change in the position of the fixed constraint thereby shifting the domain wall on dsDNA. We associate this off-equilibrium domain wall motion with the unzipping activity of the helicase. We show that this proposal gives a clear and consistent explanation of the main observed features of helicases
Mechanical denaturation of DNA: existence of a low-temperature denaturation
No full textRecent theoretical predictions on DNA (deoxyribonucleic acid) mechanical separation induced by pulling forces are numerically tested within a model in which self-avoidance for DNA strands is fully taken into account. DNA strands are described by interacting pairs of self-avoiding walks which are pulled apart by a force applied at the two extremities. The whole phase diagram is spanned by extensive Monte Carlo simulations and the existence of a low-temperature denaturation is confirmed. The basic features of the phase diagram and the re-entrant phase boundary are also obtained with a simple heuristic argument based on an energy-entropy estimate
FIGURE 3 in Gastrochilus pseudocalceolaris, a new species of epiphytic orchid from India
No full textFIGURE 3. Labellum of – A, B. Gastrochilus calceolaris (Buch.-Ham. ex Sm.) D. Don; C. G. acaulis (Lindl.) Kuntze; D, E. G. pseudocalceolaris S. Dey, L. Phom, Av. Bhattacharjee, Moaakum & K. Eshuo.Published as part of Dey, Santanu, Phom, Limamanen, Bhattacharjee, Avishek & Eshuo, Kazhuhrii, 2022, Gastrochilus pseudocalceolaris, a new species of epiphytic orchid from India, pp. 295-300 in Phytotaxa 574 (4) on page 298, DOI: 10.11646/phytotaxa.574.4.5, http://zenodo.org/record/738910
When a DNA triple helix melts: an analogue of the Efimov state
No full textThe base sequences of DNA contain the genetic code, and, to decode it, a double helical DNA has to be unzipped to reveal the bases. Recent studies have shown that a third strand can be used to identify the base sequences, not by opening the double helix but rather by forming a triple helix. It is predicted here that a three-strand DNA exhibits the unusual behaviour of the existence of a three-chain bound state in the absence of any two being bound. Such a state can occur at or above the duplex melting point. This phenomenon is analogous to the Efimov state in three-particle quantum mechanics. A scaling theory is used to justify the Efimov connection. Real space renormalization group (RG) and exact numerical calculations are used to validate the prediction of a biological Efimov effect
Yeast metabolism in fresh and frozen dough : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, Palmerston North, New Zealand
No full textAuthor also known as SM LovedayFresh bakery products have a very short shelf life, which limits the extent to which manufacturing can be centralised. Frozen doughs are relatively stable and can be manufactured in large volumes, distributed and baked on-demand at the point of sale or consumption. With appropriate formulation and processing a shelf life of several months can be achieved.Shelf life is limited by a decline in proofing rate after thawing, which is attributed to a) the dough losing its ability to retain gas and b) insufficient gas production, i.e. yeast activity. The loss of shelf life is accelerated by delays between mixing and freezing, which allow yeast cells the chance to ferment carbohydrates.This work examined the reasons for insufficient gas production after thawing frozen dough and the effect of pre-freezing fermentation on shelf life. Literature data on yeast metabolite dynamics in fermenting dough were incomplete. In particular there were few data on the accumulation of ethanol, a major fermentation end product which can be injurious to yeast.Doughs were prepared in a domestic breadmaker using compressed yeast from a local manufacturer and analysed for glucose, fructose, sucrose, maltose and ethanol. Gas production after thawing declined within 48 hours of frozen storage. This was accelerated by 30 or 90 minutes of fermentation at 30;C prior to freezing.Sucrose was rapidly hydrolysed and yeast consumed glucose in preference to fructose. Maltose was not consumed while other sugars remained. Ethanol, accumulated from consumption of glucose and fructose, was produced in approximately equal amounts to CO2, indicating that yeast cells metabolised reductively.Glucose uptake in fermenting dough followed simple hyperbolic kinetics and fructose uptake was competitively inhibited by glucose. Mathematical modelling indicated that diffusion of sugars and ethanol in dough occurred quickly enough to eliminate solute gradients brought about by yeast metabolism
Converting SrI <sub>2</sub> :Eu <sup>2+</sup> into a near infrared scintillator by Sm <sup>2+</sup> co-doping
No full text The luminescence and scintillation properties of SrI 2 single crystals doped with 5% Eu 2+ and 0.05%, 0.2% and 0.5% Sm 2+ are evaluated. X-ray excited and photoluminescence measurements show energy transfer from excited Eu 2+ ions to Sm 2+ ions. At a concentration of 0.5% Sm 2+ , the luminescence consists almost entirely of 740 nm emission from Sm 2+ 5d-4f transitions. Co-doping SrI 2 :5% Eu 2+ with Sm 2+ provides a novel method to bypass the self-absorption problem encountered in large SrI 2 :Eu 2+ crystals and, at the same time, provides a unique near-infrared emitting scintillator with a light yield of approximately 40,000 photons/MeV. Accepted Author ManuscriptRST/Fundamental Aspects of Materials and EnergyRST/Luminescence Material
'Laws 'Needefull in Later to be Abrogated': Intersex and the Sources of Christian Theology
No full textThis is the author accepted manuscript. The final version is available from Palgrave Macmillan via the DOI in this record
Introduction: Troubling Bodies?
No full textThis is the author accepted manuscript. The final version is available from Palgrave Macmillan via the DOI in this record
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