1,394 research outputs found
Fragmentation of chloroplast coupling factor in dependence of bound nucleotides Preparation of a reconstitutionally active form of subunit δ
AbstractPrevious studies on the ability of CF1, fragments to reconstitute photophosphorylation in CF1,-depleted thylakoids have shown that the degree of reconstitution was correlated with the presence of subunit δ in the fragment. This was taken as evidence that subunit δ was necessary for plugging the active proton channel CF0 [(1986) Eur. J. Biochem. 160, 635–643]. We questioned whether or not δ alone had this ability. In order to obtain δ we investigated the role of bound nucleotides in the stability of CF1. Starting from ammonium sulfate-precipitated CF1, we found that a low content of bound ADP (1 mol ADP/mol CF1) seemed to stabilize the β—δ interaction, while loosening the interaction between α,β and γ. By elution from an anion-exchange column in the presence of the nonionic surfactant Mega 9 we obtained β3δ and CF1(—δ) (both containing one ADP) or, after washing with alcohol/glycerol mixtures, β (nucleotide-free) and CF1/CF1(—ϵ). On the other hand, with a further 2 ADP and 2 ATP bound to CF1, (after incubation with excess ATP) the α-β-γ interaction was stabilized in such a way that subunit δ alone could be isolated from the complex. Subunit δ, when isolated by this procedure and added back to CF1-depleted thylakoids, reconstituted a high rate of photophosphorylation
Charge-Spin Separation in 2D Fermi Systems: Singular Interactions as Modified Commutators, and Solution of 2D Hubbard Model in Bosonized Approximation
The general 2-dimensional fermion system with repulsive interactions
(typified by the Hubbard Model) is bosonized, taking into account the finite
on-shell forward scattering phase shift derived in earlier papers. By taking
this phase shift into account in the bosonic commutation relations a consistent
picture emerges showing the charge-spin separation and anomalous exponents of
the Luttinger liquid.Comment: Latex file 14 pages. email: [email protected]
An evaluation of integrated spatial technology framework for greenhouse gas mitigation in grain production in Western Australia
The International Panel on Climate Change (IPCC) predicts an increase of 0.2 C per decade for the nexttwo decades in global temperatures and a rise of between 1.5 and 4.5 C by the year 2100. Related to theincrease in world temperatures is the increase in Greenhouse Gases (GHGs) which are primarily made upof carbon dioxide (CO2), nitrous oxide (N2O), methane (CH4) and fluorinated gases. In 2004, the GHGsfrom agriculture contributed 14% of the overall global GHGs made up mainly of methane (CH4) andnitrous oxide (N2O) emissions. In Australia, the dominant source of CH4 and N2O emissions for the yearending June 2012 was found to be from the agricultural sector. With the recent introduction of the CleanEnergy Act 2011, the agricultural sector of Australia is expected to develop appropriate GHG mitigationstrategies to maintain and improve its competitiveness in the green commodity market. This paperproposes the use of Integrated Spatial Technologies (IST) framework by linking Life Cycle Assessment(LCA), Remote Sensing (RS) and Geographical Information Systems (GIS). The IST approach also integratesand highlights the use of Cleaner Production (CP) strategies for the formulation and application of costeffectiveGHG mitigation options for grain production in Western Australia (WA). In this study, the ISTframework was tested using data from an existing study (the baseline study) and two mitigation options.The analysis results revealed production and use of fertiliser as the “hotspot”, and for mitigation purposeswas replaced with pig manure in option 1, whereas option 2 emphasised crop rotation system/s
An industry-sponsored, school-focused model for continuing professional development of technology teachers
Traditionally a divide has existed between faculties of education at higher
education institutions (HEIs) and trade and industry, but the business sector is
increasingly buying into community development with corporate social investment,
especially regarding technology education. We report on a continuing
professional teacher development (CPTD) model, which entails trade and
industry sponsoring learning and teacher support material (LTSM) for technology
education in under-resourced schools, paying for LTSM through their corporate
social investment funds, and sponsoring CPTD of technology teachers where
they are trained to use LTSM more efficiently. Trade and industry, together with
HEIs and Departments of Education (DoE), could change the traditional concept
that CPTD is the responsibility of DoEs into a new model where the business
sector shares some of the responsibility for equipping teachers so that they can
provide quality education. We argue that custom-made and sponsored LTSM
and CPTD play an important role in the training and empowerment of technology
teachers. Keywords: continuing professional development; learning and teacher support material; technology education South African Journal of Education Vol. 27 (4) 2007: pp. 579-59
One-Particle Excitation of the Two-Dimensional Hubbard Model
The real part of the self-energy of interacting two-dimensional electrons has
been calculated in the t-matrix approximation. It is shown that the forward
scattering results in an anomalous term leading to the vanishing
renormalization factor of the one-particle Green function, which is a
non-perturbative effect of the interaction U. The present result is a
microscopic demonstration of the claim by Anderson based on the conventional
many-body theory. The effect of the damping of the interacting electrons, which
has been ignored in reaching above conclusion, has been briefly discussed.Comment: 7 pages, LaTeX, 1 figure, uses jpsj.sty, to be published in J. Phys.
Soc. Jpn. 66 No. 3 (1997
Numerical Evidence of Luttinger and Fermi Liquid Behaviour in the 2D Hubbard Model
The two dimensional Hubbard model with a single spin-up electron interacting
with a finite density of spin-down electrons is studied using the quantum
Monte Carlotechnique, a new conjugate gradient method for the evaluation of
the Edwards wavefunction ansatz, and the standard second order perturbation
theory. We performed simulations up to 242 sites at reaching the zero
temperature properties with no ``fermion sign problem'' and found a
surprisingly good accuracy of the Edwards wavefunction ansatz at low density or
low doping. The conjugate gradient method was then applied to system up to 1922
sites and infinite for the Edwards state. Fermi liquid theory seems to
remain stable in 2D for all cases studied with the exception of the half
filling case where a ``Luttinger like behavior'' survives in the Hubbard model
, yielding a vanishing quasiparticle weight in the thermodynamic limit.Comment: 10 pages + 4 pictures, RevTex, SISSA 121/93/CM/M
A multifaceted hospital-wide intervention increases hand hygiene compliance
Background. Hand hygiene is an important and basic practice that should be used by all healthcare staff to protect both themselves and their patients against infection. Unfortunately hand hygiene compliance remains poor.Objective. To show an improvement in hand hygiene compliance using a multifaceted approach.Methods. This was a quasiexperimental pre-post intervention study design with a number of standardised interventions to promote hand hygiene. The World Health Organization hand hygiene multimodal (five-step) intervention approach was used. The study ran from June 2015 to August 2015 in 11 selected wards of a 975-bed tertiary and quaternary care public hospital (Groote Schuur Hospital, Cape Town, South Africa). The outcome was to assess improvement in hand hygiene compliance monthly over the 3 months, compared with nonintervention wards and compared with the wards’ own performance measured in 2014. The study included both descriptive and analytical components.Results. Post intervention, hand hygiene compliance showed a statistically significant improvement for before patient contact from 34% in 2014 to 76% in 2015 (p<0.05) and for after patient contact from 47% in 2014 to 82% in 2015 (p<0.05).Conclusion. The intervention improved hand hygiene compliance and can easily be replicated in other wards, resulting in sustaining a culture of hand hygiene improvement and behavioural change throughout the hospital
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Cellular Structures for Optimal Performance
Cellular material structures, such as honeycombs and lattice structures, enable
unprecedented stiffness and strength characteristics, for a given weight. New design and CAD
technologies to construct cellular materials are presented in this paper. Such materials have very
complex geometries, hence the need for additive manufacturing processes to produce them. A
series of experiments was performed to build and test parts fabricated using Selective Laser
Sintering. Variations in mechanical properties were quantified and related to processing
conditions. Examples help illustrate the variety of applications of cellular materials in the
aerospace, automotive, motorsports, energy, electronics, and related industries. A software tool
is being developed to enable users to design and construct parts with cellular structures.Mechanical Engineerin
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