bluuebunny/crossref_metadata_2025 huggingface dataset:
Putting halophytes to work – genetics, biochemistry and physiology
Authors: Huchzermeyer Bernhard , Flowers Tim
Published: November 2018

Halophytes are a small group of plants able to tolerate saline soils whose salt concentrations can reach those found in ocean waters and beyond. Since most plants, including many of our crops, are unable to survive salt concentrations one sixth those in seawater (about 80 mM NaCl), the tolerance of halophytes to salt has academic and economic importance. In 2009 the COST Action Putting halophytes to work – from genes to ecosystems was established and it was from contributions to a conference held at the Leibniz University, Hannover, Germany, in 2012 that this Special Issue has been produced. The 17 contributions cover the fundamentals of salt tolerance and aspects of the biochemistry and physiology of tolerance in the context of advancing the development of salt-tolerant crops.
Two Remarks Concerning the Signs of the Light Quark Masses
Authors: Genz Henning
Published: November 2018

Partial conservation of the nine axial currents
Abµ for β = 0,
1,..., 8 applied to the vacuum expectation values of the equal-time
commutators of the nine axial charges
QαA
(x0) for α = 0,
1,..., 8 and the corresponding axial current divergences
∂µAβµ
implies that the non-vanishing current quark masses
mυ,
md,
ms of the light quarks
u, d, shave
the same sign. Under the more realistic assumption of partial conservation of
only the eight axial currents of SU(3) ⊗
SU(3), i.e. a = 1,..., 8 and β =
1,..., 8 in the above, inequalities for the quark masses follow. They are
trivially fulfilled if the three light quark masses have the same sign and
imply, for non-vanishing quark masses
mu,
md,
ms that at least two of these
masses have the same sign as their sum
mu +
md +
ms. If one of the three quark
masses vanishes, one of the other two might also. If both do not, they have
the same sign (the same, of course, as their sum). Our assumptions include the
standard vector SU(3) symmetry of the vacuum.
Some Physical Implications of the Gravitoelectromagnetic Field in Fractal Space - Time Theory
Authors: Agop M. , Griga V. , Buzea C. Gh. , Rezlescu N. , Buzea C. , Marin C. , Petreus I.
Published: November 2018

It is shown that in terms of the fractal space–time theory the
gravitoelectric potential is responsible for the quantisation of the planetary
and binary galaxy motions. On a cosmic scale a homogeneous gravitomagnetic
field allows not only an ordering of the Universe, but a ‘global’
redshift quantisation of galaxies as well.
Guidelines for ecological burning regimes in Mediterranean ecosystems: a case study in Banksia woodlands in Western Australia.
Authors: Wilson Barbara A , Kuehs Janine , Valentine Leonie E , Sonneman Tracy , Wolfe Kristen M
Published: November 2018

In Mediterranean ecosystems prescribed burning is commonly employed to reduce the risk or intensity of wildfires.
As a consequence, a major challenge for conservation land managers is the development of fire regimes that reduce
damaging wildfires and are optimal for biodiversity. The aim of this paper was to develop guidelines for ecological fire
regimes using the Banksia woodland on the Gnangara Groundwater System in Western Australia as a case study.
Development of the guidelines involved the determination of maximum and minimum fire intervals of key fire response
species, analyses of fire history records and estimation of ideal age class distributions at the landscape level.
Recommendations included a) adoption of a minimum fire interval of 8–16 years, b) implementation of a burning regime
to redress the current skewed distribution (60%: 1–7 years since last fire), c) retention of long-unburnt habitats that
are significant for species such as the critically endangered Calyptorhynchus latirostris (Carnaby’s black-cockatoo), and
Tarsipes rostratus (honey possum), and d) protection for wetlands that can serve as fire ‘refugia’ for associated species,
such as Isoodon obesulus fusciventer (southern brown bandicoot or quenda). The guidelines developed provide a model
for the development of ecological burning regimes in other similar ecosystems. The implementation of ecological
guidelines normally involves incorporation into fire management planning by fire agencies and often entails complex
solutions to conflicting aims. The guidelines are thus valuable for ecologists and land managers, especially in light of
an expected significant increase in global fire activity as a consequence of predicted climate change.
Discovery of Australia’s Fishes: A History of Australian Ichthyology to 1930.
Authors: Fulton Graham R
Published: November 2018

BRIAN Saunders is a retired ophthalmologist with a lifetime interest in marine biology and the history of ichthyology. He has previously published Shores and Shallows of Coffin Bay: An Identification Guide, in 2009, revised in 2012. That work, in its revised edition, contains extensive figures and supplementary information on other ecological parameters such as fish parasites and the habitat of the Coffin Bay area. The current work is a much greater labour, which relies on a significant knowledge of the Australian fish fauna and extensive research of the scientific and historical literature. This volume is about the discovery of Australia’s fishes (to 1930) following the main systematic and taxonomic research in Australia with the inclusion of the pertinent discoveries from further afield in the Indian and western Pacific Oceans. It treats only lightly the ichthyologic and Aboriginal lore, which is outside the intent and scope of the book.
Quenching of the 2D Metallic State by Aligning the Electron Spins
Authors: Thakur J. S. , Neilson D.
Published: November 2018

We discuss the destabilisation of the electron 2D metallic state by an
in-plane magnetic field. We demonstrate that such a field can destabilise the
metallic state through spin polarisation which significantly enhances the
exchange correlations between electrons. We find that the conducting phase of
the fully spin polarised system is almost completely suppressed. We discuss
this phenomenon within a memory function formalism which treats both disorder
and exchange-correlation effects. We determine the shift in the position of
the metal–insulator phase boundary as the system is polarised by an
increasing parallel magnetic field.
Finite Temperature Correlation Functions of One-dimensional Interacting Electron Systems
Authors: Bowen G. , Gulácsi M. , Rosengren A.
Published: November 2018

The well-known bosonisation method of one-dimensional electron systems is
extended to finite temperatures. As an example, the correlation functions of
the non-interacting case are explicitly calculated. The presentation is
pedagogical and is intended to be accessible to graduate students or
physicists who are not experts in this field.
Absorptive Quantum Measurements via Coherently Coupled Quantum Dots
Authors: Milburn G. J. , Sun H. B. , Upcroft B.
Published: November 2018

We propose an absorptive measurement scheme via coupled quantum dots based on
studies of the quantum dynamics of coherently coupled dots. The system is
described through a Markov master equation that is related to a measurable
quantity, the current. We analyse the measurement configuration and calculate
the correlations and noise spectra beyond the adiabatic approximation.
Effect of Interfaces on Dielectric Relaxation in La0.35Sr0.6MnO3 -YSZ
Authors: Zheng-Cai Xia , Chao-Qun Tang , Dong-Xiang Zhou , Jian-Hui Yang
Published: November 2018

The perovskite structure material La 0.35 Sr
0.6 MnO 3 was sintered in air and
the mixed ceramic of a 0.35 Sr 0.6
MnO 3 and 8 mol % Y 2 O
3 +ZrO 2 with a 1:1 mass rate
was also sintered in air, both at 1530 K for 12 hour. The AC complex impedance
spectra have been measured and the effect of the interface between La
0.35 Sr 0.6 MnO
3 and YSZ on dielectric relaxation properties of La
0.35 Sr 0.6 MnO
3 has been investigated. A schematic of diffusion phase
formation and the equivalent circuits are proposed for explaining the results.
In the complex impedance spectra, the first and second semicircles correspond
to the grain-boundary and interface respectively. The results show that the
dielectric relaxation properties and structure of the mixed ceramic are
different to that of single phase La 0.35 Sr
0.6 MnO 3 . The interface has an
important effect on the electric properties of the mixed ceramic and produces
a dielectric relaxation in low frequency.
Generation of Multicavity Entangled States with a Single Three-Level Atom
Authors: Zheng Shi-Biao
Published: November 2018

A simple scheme is proposed for the generation of maximally entangled states
for several separated cavities, in which each cavity is in a one-photon state
or in the vacuum state. In the scheme a laddertype three-level atom is sent
through the cavities and additional classical fields. The whole system finally
evolves into a state, which is given by the product of the highly entangled
field state with an atomic state.
Acoustic Vibrational Properties and Fractal Bond Connectivity of Praseodymium Doped Glasses
Authors: Senin H. B. , Sidek H. A. A. , Saunders G. A.
Published: November 2018

The velocities of longitudinal and shear ultrasonic waves propagated in the
(Pr2O3)x(P2O5)1-x
glass system, where x is the mole fraction of
Pr2O3 and (1 -
x) is the mole fraction of
P2O5, have been measured as
functions of temperature and hydrostatic pressure. The temperature
dependencies of the second order elastic stiffness tensor components (SOEC)
CS
IJ , which have been determined
from the velocitydata between 10 and 300 K, show no evidence of phonon mode
softening throughout the whole temperature range. The elastic stiffnesses
increased monotonically, the usual behaviour associated with the effect of the
phonon anharmonicityof atomic vibration. At low temperatures, strong phonon
interactions with two-level systems have been observed. The ultrasonic wave
attenuation of longitudinal and shear waves is dominated bya broad acoustic
loss peak whose height and peak position are frequencydependent. This
behaviour is consistent with the presence of thermally activated structural
relaxation of the two-level systems in these glasses. The fractal bond
connectivity of these glasses, obtained from the elastic stiffnesses
determined from ultrasonic wave velocities, has a value between 2.32 to 2.55,
indicating that their connectivitytends towards having a threedimensional
character. The hydrostatic pressure dependencies of longitudinal ultrasonic
waves show a slight increase with pressure. As a consequence, the hydrostatic
pressure derivatives (
CS11/
P)P=0 of the elastic
stiffness
CS11/
and
(BS/P)P=0
of the bulk modulus BS of
(Pr2O3)x(P2O5)1-x
glasses are positive. The bulk modulus increases with pressure, and thus these
glasses stiffen under pressure, which is associated with the normal elastic
behaviour. The GrÜneisen parameter approach has been used to quantifythe
vibrational anharmonicityof the long-wavelength acoustic phonons in these
glasses.
A General Equation for the Choice of Glass for Cemented Doublets
Authors: Steel WH
Published: November 2018

A general equation is derived for the choice of glass for cemented doublet objectives for any object distance or residual aberration. The case where the aberrations are zero is studied in detail.
Stress Relaxation of Wool Fibres in Water at Strains of 5?20 Per Cent
Authors: Rigby BJ
Published: November 2018

A study has been made of the stress relaxation at fixed longitudinal strains of wool fibres immersed in water, in the post-yield region of their load-strain curves. The fibres were extended at controlled rates up to predetermined strains, particular attention being paid to the first few minutes of the subsequent stress relaxation. It was found that the relaxation curves so obtained could be represented by a sum of one, two, or three negative exponentials, which could, in general, be simplified into two main processes, (a) a relatively fast relaxation of stress occurring in about the first 60 sec and (b) a much slower relaxation.
Multiple Images in Reflecting Microscopes
Authors: Steel WH
Published: November 2018

The normal image of a reflecting microscope is formed by a single reflection at each mirror surface. However, other images are possible ; higher order images formed by two or more reflections at each surface, and a zero order "image" which is the object itself, if there is an unobstructed light path through the system. In a mirror system possessing central obscuration of the pupil, this unwanted light usually does not reach the axial image point, but it may give rise to a spread of light across the outer parts of the field, so reducing the contrast. The effects of these extra images are most noticeable when the objective is used in reverse as a condenser.
Reciprocal Static Solutions of the Equations of the Gravitational Field
Authors: Buchdahl HA
Published: November 2018

This paper deals with reciprocal static line-elements, previously defined by the author, the condition that their Ricci tensors vanish being no longer imposed. If the indices i, k run from 1 to n with the exception of the fixed index a (the line-elements being static with respect to xa) a certain quantity appears with the remarkable property that in a reciprocal transformation is invariant, whilst merely changes sign. is closely related to the Hamiltonian derivative of the Gaussian curvature, so that the general results obtained may be applied to the field equations of General Relativity Theory, with n=a=4. is then the total energy density; and formally every static distribution of matter has a " reciprocal distribution" associated with it. In particular, the equation of state of a distribution of fluid reciprocal to a distribution of fluid possessing a given equation of state may be obtained directly from the latter, i.e. without the solution of the field equations being known.
The Fitting of a Truncated Log?Normal Curve to Daily Rainfall Data
Authors: Das SC
Published: November 2018

In a previous paper (Das 1955) the author discussed a problem of curve fitting which arose in testing the hypothesis proposed by Bowen (1953) concerning daily rainfall data.
An Analogy Between the Effects of Fluctuating Electric Fields and Steady Magnetic Fields in Isotropic Conductors when a Universal Relaxation Time Cannot Be Defined
Authors: Moore EJ
Published: November 2018

It is well known that when a " universal" time of relaxation ("t') exists, the influence of a harmonically varying electric field (F cceiOlt) on the transport properties of a solid may be taken into account by replacing "t' by "t'/(l +iCil"t'). Dingle (1956a) demonstrated that, for an isotropic solid, the effect of a steady magnetic field may similarly be obtained by replacing "t' by "t'/(l+j~l"t') with an applied d;c. electric field, and by "t'/[l+(iCil+jO)"t'] with an a.c. field. (Here j2= -1, ij -=1= -1, and 0=( -e)H/mc is the circular frequency of precession of an electron.) The object of the present note is to show that this analogy between a high frequency electric field and a steady magnetic field still exists, even when a " universal" relaxation time cannot be defined.
Characteristics of the Solitary Waves in Multicomponent Plasmas
Authors: Das GC , Karmakar B
Published: November 2018

We have investigated ion-acoustic solitary waves in a multicomponent plasma. The study shows an interaction of the negatively charged particles with the solitary waves, due to which interesting physical behaviour of the solitary waves is observed. Moreover, the isothermality and the non-isothermality of the plasma exhibit different soliton-type solutions and a transition of the soliton's behaviour can be shown through the changes of the non-isothermality in the plasma.
The Effect of Sintering Temperature on the Barrier Height of p-type PtSi Schottky Diodes
Authors: WL Chin Vincent , M Newbery Stephen , WV Storey John , Theden Ulrich
Published: November 2018

The effect of sintering temperature on the barrier height of p-type PtSi Schottky diodes is studied by electrical and infrared photoresponse methods. It is revealed that there is a consistent difference of about 0�06 eV for two samples sintered at different temperatures.
The Challenge of the EMC Effect
Authors: Thomas AW , Saito K , Michels A
Published: November 2018

A number of relatively successful quark model descriptions of nuclear matter have recently been developed, based on a mean-field description of non~overlapping nucleons bound by the self-consistent exchange of (1' and w mesons. By combining one such model with a recently developed method of calculating structure functions for the free nucleon, we are able tc. make a microscopic calculation of the structure functions of finite nuclei (in the local density approximation). As well as providing a semi-quantitative understanding of existing data, the model suggests that the impulse approximation, used in many theoretical treatments of nucleon binding, may be quite unreliable.
Water Vapour and Its Role in the Earth's Greenhouse
Authors: L Stephens Graeme , A Tjemkes Stephen
Published: November 2018

This paper examines the role of water vapour as a greenhouse gas and discusses its role in the evolution of the atmospheres of Venus, Earth and Mars. The paper focuses on how the greenhouse effect operates on Earth and describes the feedback between temperature and water vapour that is thqught to play a key role in global warming induced by increasing concentrations of carbon dioxide. A method for analysing the contribution of water vapour to the greenhouse effect using satellite observations is discussed. It is shown how this contribution varies in a directly proportional way with the amount of water vapour vertically integrated through the column of the atmosphere. Based on the results obtained from the analyses of satellite data, it is established that the sensitivity of the greenhouse effect to changing sea surface temperature is not uniform over the globe and is significantly greater over warmer oceans. The relevance of the results to the water vapour feedback is discussed.
Spectroscopic and Piezospectroscopic Studies of the Energy States of Boron in Silicon
Authors: Lewis RA , Fisher P , McLean NA
Published: November 2018

The P3/2 optical absorption spectrum of boron impurity in silicon has been re-examined at high resolution. The precise transition energies measured agree with energies previously reported. In addition, energies for several previously unrecognised transitions are given as well as values for the absorption strengths and line widths. The measured transition energies and absorption strengths correlate very well with several recent calculations of binding energies and oscillator strengths, respectively. This excellent agreement between experiment and theory motivates a renumbering of the spectral lines which is not expected to require future modification. High-resolution piezospectroscopy of the P3/2 series has also been undertaken. Small stresses were used to minimise the effect of interactions and permit accurate determination of the deformation potential constants. The deformation potential constants are found to be in fair agreement with previous experimental values and good agreement with recent theory. Experimental values for several of these are given for the first time, as are isotropic deformation potential constants of several excited states relative to the ground state.
X-ray Phase-contrast Imaging Study of Voids and Fibres in a Polymer Matrix
Authors: Gao Dachao , J Davis Timothy , W Wilkins Stephen
Published: November 2018

We report X-ray phase-contrast images of voids and glass fibres in a polymer matrix. The phase-contrast images are obtained using both a monolithic 3-refiection asymmetric channel-cut monochromator and analyser with 1�54 A X-rays. The mechanisms of contrast formation in the images of voids and glass fibres are discussed in detail and numerical simulations of the images are found to agree with the experiments.
Thermonuclear Reaction Rates for Reactions Leading to N = 28 Nuclei
Authors: Morton A.J , Sargood DG
Published: November 2018

Nuclear reaction cross sections derived from statistical-model calculations have been used in the calculation of thermonuclear reaction rates for 36 nuclei at temperatures that are representative of the interiors of evolving stars and supernovae as nucleosynthesis approaches the production of nuclei with N = 28. The statistical-model calculations used optical-model parameters in the particle channels which had been selected to give the best overall agreement between theoretical and experimental cross sections for reactions on stable target nuclei in the mass and energy ranges of importance for the stellar conditions of interest. The optical-model parameters used, and the stellar reaction rates obtained, are tabulated. Comparisons are made between these stellar rates and those from other statistical-model calculations in the literature.
Some implications of the gravitomagnetic field in fractal spacetime theory.
Authors: Agop M. , Matsuzawa H. , Oprea I. , Vlad R. , Sandu C. , Buzea C. Gh.
Published: November 2018

In a fractal spacetime, the absence of a gravitational Meissner effect is
thought of as ordering space as a crystal, at both a microscopic and a
macroscopic scale. A gravitational Meissner effect keeps a wormhole open and
penetrable and, in the same context, a gravitational superconductor levitates
in an external gravitomagnetic field, an external gravitomagnetic field
induces quantised vortices in a gravitational superconductor and gravitational
rotons in a superfluid, and the planetary systems are self-organised as
superconducting structures.
Preparation of superpositions of SU(2) coherent states of the motion of a trapped ion.
Authors: Zheng Shi-Biao
Published: November 2018

A scheme is presented for the generation of superpositions of two two-mode
SU(2) coherent states of the motion for a trapped ion. In the scheme an ion is
trapped in a two-dimensional isotropic harmonic potential and driven by two
resonant laser beams. Under certain conditions, the motional two-mode SU(2)
cat state can be generated after a conditional measurement on the internal
state following the ion-laser interaction.
Position Indeterminacy
Authors: Ruzzene Fosco
Published: November 2018

Calculations assuming position indeterminacy in the Dirac equation are
reported.Energy shift contributions for low-lying states of hydrogen-like
atoms are calculated by treating the position indeterminacy as a perturbation
additional to standard quantum mechanics. The results are consistent with the
current discrepancy between theory and experiment for Lamb shifts in hydrogen,
deuterium and the helium ion.
Flux and reactive contributions to electron transport in methane.
Authors: Ness K. F. , Nolan A. M.
Published: November 2018

A previously developed theoretical analysis (Nolan
et al. 1997) is applied to the study of electron
transport in methane for reduced electricfields in the range 1 to 1000 Td. The
technique of analysis identifies the flux and reactive components of the
measurable transport, without resort to the two-term approximation. A
comparison of the results of the Monte Carlo method with those of a multiterm
Boltzmann equation analysis (Ness and Robson 1986) shows good agreement. The
sensitivity of the modelled electron transport to post-ionisation energy
partitioning is studied by comparison of three ionisation energy partitioning
regimes at moderate (300 Td) and high (1000 Td) values of the reduced
electricfield.
General Gauge Independence of Diamagnetism plus Paramagnetism
Authors: Stewart A. M.
Published: November 2018

With the use of the generalised multipolar gauge, a completely general proof
is obtained for a result asserted by J. H. Van Vleck in 1932 but never fully
proved by him. Specifically it is demonstrated that the matrix elements of the
magnetic moment operator are independent of the origin of the vector potential
for electromagnetic fields that are non-uniform in space and non-constant in
time. A general survey of the principles of the quantum mechanics of solid
state and molecular magnetism is also given to set the problem in its context.
Based on the multipolar gauge, a simple conversion of the interaction
Hamiltonian from the form of A.p to
E.r plus higher order terms is demonstrated.
Fluxes of Potassium and Changes in Malate within Epidermis of Commelina cyanea and their Relationships with Stomatal Aperture
Authors: Pearson C.J
Published: November 2018

Stomatal apertures and concentrations of potassium, malate and sugars within the epidermis were
measured during stomatal opening and closure; the location of K+ was also estimated by cobaltinitrite
staining. The concentration of K+ in the epidermis as a whole did not change during stomatal
opening and closure, but K+ migrated between epidermal and guard cells. Concentrations of sugars
also remained constant. By contrast, there was a positive relationship between concentration of
malate and aperture. These and other results emphasize an appreciable degree of isolation of the
epidermis.
Effect of Temperature on Punchthrough in Electrical Characteristics of the Plasmalemma of Chara coralinna
Authors: Beilby M.J , Coster H.G.L
Published: November 2018

At the punchthrough, the current required to maintain the hyperpolarized potential difference (p.d.) of the plasmalemma increases very rapidly with increasing hyperpolarization so that, in the steady state, the membrane cannot be hyperpolarized beyond a certain level.
It was found that punchthrough in the plasmalemma of C. corallina occurred at more negative (i.e. at greater hyperpolarizing) potentials as the temperature was decreased, from a value of ~ -310mV at T = 32�C to ~ -420 mV at T = 5�C.
Some considerations are given to the compressive stress induced in the plasmalemma due to the electric field. These stresses at the p.d. values required for punchthrough are very considerable (~ 3 x 10*6 Nm*-�), and could lead to significant strains in the membrane.
The degree of electromechanical compression of the membrane would increase with increasing temperature if, as the evidence cited suggests, the elastic modulus of the membrane decreases with increasing temperature. This would account for the decrease in the absolute value of the p.d. required for punchthrough with increasing temperature.
Stomatal Metabolism: Primary Carboxylation and Enzyme Activities
Authors: Thorpe N , Brady C.J , Milthorpe F.L
Published: November 2018

Malate and aspartate are the major labelled products when 14CO2 is offered to epidermal strips of Commelina cyanea R.Br. Thirty seconds after initial exposure to 14CO2 of strips in light with open stomata, 75 % of 14C in aspartate was a [4-14C]aspartate. As the exposure time increased, the ratio [4-14C]aspartate to [U-14C]aspartate declined. This evidence indicates that 14C enters aspartate after a �-carboxylation reaction and that the newly formed aspartate is further metabolized by the tissue.
Ribulosebisphosphate carboxylase fractionated similarly on sucrose density gradients whether from intact leaf or epidermal strips and, from either tissue, the activity was inhibited by antisera to purified fraction 1 protein from wheat. Phosphoenolpyruvate carboxylase from mesophyll and epidermis also coincided on sucrose density gradients. A survey of enzymic activities in extracts of leaves and epidermes showed that the latter were specialized towards the metabolism of C*4 acids. They have a high ratio of phosphoenolpyruvate to ribulosebisphosphate carboxylase activities, and enhanced amounts of aspartate aminotransferase, malate dehydrogenase (NADP+), and NAD : malic and NADP : malic enzymes. Pyruvate, orthophosphate dikinase or phosphoenolpyruvate carboxykinase, enzymes possibly involved with C*4 acid metabolism, were not detected.
The Action Potential in Chara corallina III.* The Hodgkin-Huxley Parameters for the Plasmalemma
Authors: Beilby M.J , Coster H.G.L
Published: November 2018

An analysis, based on the Hodgkin-Huxley (H-H) equations is given of excitation processes in the plasmalemma of cells of C. corallina. Voltage clamp data for the plasmalemma show the presence of two activation and two inactivation processes and both of these transients are modelled in a manner analagous to the gated Na+ current in squid axons. Separation of the various ionic components of the experimental clamp currents was achieved by fitting the experimental data over a wide range of potentials to the model equations.
The potential dependencies of the various H-H parameters for C. corallina, determined from the analysis of experimental results, are presented. A reconstruction is also given of the action potential and it is shown to be in satisfactory agreement with the experimental data. Comparisons are made of the experimental and predicted threshold potential, refractory period and the effects of the external Cl- and Ca�+ ion concentrations on the action potential. From the H-H parameters, the time courses during an action potential of the conductances g*Cl, g*x (� g*Ca?), the non activated/inactivated steady-state conductance g*ss, and the corresponding ionic currents I*Cl, I*x (� I*Ca?) and I*ss are calculated.
While in the H-H analysis the peak value of g*x is found to be very large (larger than the peak value of g*Cl), it is shown that nevertheless I*Cl and I*ss dominate during an action potential.
The Action Potential in Chara corallina IV.* Activation Enthalpies of the Hodgkin-Huxley Gates
Authors: Beilby M.J , Coster H.G.L
Published: November 2018

Voltage-clamp experiments were made to determine the effect of temperature on the Hodgkin-Huxley parameters describing the excitation of the plasmalemma of C. covallina. In these cells two activated and inactivated transients in addition to a potential-dependent leak conductance occur during excitation.
The activation and inactivation time constants for both the Cl- and X (� Ca�+?) channels decreased with increasing temperature. The relative changes with temperature, however, were the same at all potentials. That is, the thermodynamic activation enthalpies for activation and inactivation were independent of membrane potential. This suggests that these parts of the gating processes do not involve movement, normal to the membrane, of charged moieties (other than the ions carrying the clamp currents).
For clamps beyond the threshold, both gated current transients occur only after a delay, the latter being strongly dependent on the clamp potential. The delays �*Cl and �*x in the Cl- transient and X (� Ca�+?) transients, respectively, both decreased with increasing temperature, having values �*Cl � 0.8 s and �*x � 2.5 s at - 110 mV and 20�C. Apparently activation/inactivation commenced only after the resting-state channels had been transformed into some precursor state for excitation.
The activation enthalpy for this transformation varied linearly with membrane clamp potential at a rate of ~ - 390 kJ per mol per volt and ~ -960 kJ per mol per volt for the CI- and X (� Ca�+?) channels respectively. The transformation to the precursor state therefore required the same energy as the separation (positive charges outwards, negative charges inwards), normal to the plasmalemma, of ~4 and ~10 charges per molecule for the Cl- and X channels, respectively.
The Double-fixed-charge Membrane: Electromechanical Stress and the Effects of Temperature on Punchthrough
Authors: Beilby Mary. J , Coster H.G.L
Published: November 2018

An analysis is given of the effects of electromechanical compression (electrostriction) on the
electrical characteristics of double-fixed-charge membranes. It is shown that the voltage-current
characteristics of Chaua couallina, and in particular the punchthrough potential, as a function of
temperature can be accounted for on the basis of the double-fixed-charge membrane model when
electrostrictive effects are taken into account.
Transport of Metabolites between the Mesophyll and Epidermis of Commelina cyanea R. Br.
Authors: Thorpe N , Milthorpe F.L
Published: November 2018

The concentrations of 10 major metabolites in the epidermis were one-third to one-half of those in
the mesophyll when the stomata were open. I4CO2 was supplied to the leaf and the radioactivity
contained in glucose, sucrose, sugar phosphates, malate, glycine, serine and alanine, and the ethanolinsoluble
HC1-hydrolysable fraction was followed for 2 h in both the mesophyll and epidermis. The
net fluxes from mesophyll to epidermis were in the range 0.7-4 nmol m-2 s-I when the leaf was
actively photosynthesizing and fell to near zero or became negative with no net photosynthesis. Fluxes
were largely independent of concentration differences, which did not vary greatly from initial values.
Although the amounts reaching the epidermis greatly exceeded those fixed from C02 in situ, available
evidence suggests that the epidermis may have the capacity to supply its own carbon needs; the carbon
imported no doubt supplies extra substrates and energy and may influence the flux of K+ ions through
the guard-cell membranes. Efflux curves indicated that one-half to three-quarters of the soluble
substances in the epidermis diffused readily from it but only about 10% of those in the mesophyll
diffused rapidly.
The Role of Hormones in Wall Loosening and Plant Growth
Authors: Cleland R.E
Published: November 2018

The rate at which any plant cell enlarges is determined by the product of two cellular parameters; the wall extensibility (m) and the effective turgor (�*p - Y), where �*p is the turgor pressure and Y is the wall yield threshold. When hormones modulate the rate of cell enlargement, they do so by altering one or both of these parameters. To determine whether the affected parameter is m, one must be able to measure it. There are four methods for assessing m; the Instron technique; stress relaxation; turgor relaxation; and the growth rate v. turgor method. Each has advantages and disadvantages. Ideally, at least two methods should be used and the results should agree, at least qualitatively.
In every case so far examined, wherever auxin promotes cell elongation, it also increases m. Gibberellins and cytokinins, on the other hand, sometimes increase m and sometimes do not. Abscisic acid, in the few cases tested, decreases m, while the effects of ethylene are mixed. A change in m can occur only if the cell exports (or takes up) a wall loosening factor (WLF) in response to the hormone. In some cases the WLF must be, at least in part, protons, but in other cases it is clear that it is something different. In dicotyledonous stems it could even be the uptake of Ca�+ from the walls.
Turgor can be influenced by hormones but, with the exception of gibberellins, the responses appear to be secondary, induced by the growth processes rather than by the hormone. However, the ability of cells to take up osmotic solutes and maintain �*p may be the most important factor, in nature, modulating the growth rate of plants on an hour-to-hour basis.
Plant Growth Substances and the Regulation of Growth Under Drought
Authors: Davies W.J , Metcalfe J , Lodge T.A , da Costa A.R
Published: November 2018

This paper reviews briefly the effects of water deficits on the synthesis and distribution of plant growth
regulators with some emphasis on genotypic variation in synthesis. The effects of abscisic acid on growth
and development are also considered and interactions between growth regulators are highlighted. One
possible role for a growth regulator in providing a mechanism to regulate physiology, growth and
development as a function of water availability is discussed in detail. It is proposed that reduction in
root tip turgor will reduce the synthesis and transport of cytokinins in the root tip and that this reduced
transport, perhaps combined with drought-induced reduced uptake of nutrients from the soil, will
influence the physiology of the shoot independently from any hydraulic influence.
The Photosystem Stoichiometry in Thylakoids of Some Australian Shade-adapted Plant Species
Authors: Chow W.S , Anderson J.M , Melis A
Published: November 2018

The concentrations of functional photosystem I1 (PSII) reaction centres in leaves and photosystem I
reaction centres (P700) in thylakoids isolated from comparable leaves of Australian shade-adapted
plant species of diverse taxa, life-forms and habitats were compared. The concentrations of PSII were
determined directly in leaves by the oxygen yield per single-turnover flash in the presence of far-red
background illumination. The concentrations of P700 were determined by the light-induced absorbance
change of thylakoid membranes at 703 nm. On a chlorophyll basis, the amounts of both functional
PSII and P700 were lower in shade species than in sun species. The PSII/PSI reaction centre stoichiometries
of the shade species ranged from 1.2 to 1.9 indicating that (i) shade-adapted species do not
have a fixed 1: 1 ratio; and (ii) their PSWPSI ratios are usually lower than those of sun species
(1.7-1.8). We conclude that shade plants display variable photosystem stoichiometry. The results are
discussed in terms of the interplay between the adjustment of photosystem stoichiometry and that
of the light-harvesting chlorophyll antenna size of each photosystem in the thylakoid membrane of
shade species.
Src family kinases are involved in the meiotic maturation of porcine oocytes
Authors: Kheilová Kateřina , Petr Jaroslav , Žalmanová Tereza , Kučerová-Chrpová Veronika , Řehák Dalibor
Published: November 2018

Mammalian meiotic maturation is regulated by changes in the phosphorylation state of proteins involved in signalling pathways. The regulatory proteins include the family of Src tyrosine kinases. Src family kinases (SFKs) are required for meiotic maturation of mouse oocytes, and it remains to be elucidated whether they play the same role in porcine oocytes. To clarify the role of SFKs in the meiotic maturation of porcine oocytes we used inhibition of SFKs, western blotting and immunolocalisation to determine the presence of SFKs and localisation in the oocytes and assays to determine the activity of maturation-promoting factor (MPF) and mitogen-activated protein kinase (MAPK). Inhibition of SFKs resulted in the disruption of oocyte maturation and led to a decline in MPF and MAPK activity. The fluorescence intensity of SFKs in the cytoplasm and membrane of MI oocytes decreased significantly compared with germinal vesicle oocytes. The highest fluorescence intensity for SFKs was detected on the membrane of MII oocytes. Only weak fluorescence was detected in the perichromosomal area of MI and MII oocytes. These results prove that SFKs play an active role in the meiotic maturation of porcine oocytes by regulating MPF and MAPK activity.
122 A New Maturation Medium Improves Porcine Embryo Production In Vitro
Authors: Lucas-Hahn A. , Petersen B. , Nowak-Imialek M. , Baulain U. , Becker R. , Eylers H.-M. , Hadeler K.-G. , Hassel P. , Niemann H.
Published: November 2018

Recently (Spate et al. 2017 Reprod. Fertil. Dev. 29, 150), a new medium [TCM-199 supplemented with hCG 10 IU, pregnant mare serum gonadotropin (PMSG) 10 IU mL−1, fibroblast growth factor (FGF) 40 ng mL−1, leukemia inhibitory factor (LIF) 2000 U mL−1, IGF-1 20 ng mL−1, epidermal growth factor (EGF) 10 ng mL−1], termed FLI medium, was demonstrated to improve porcine oocyte maturation in vitro. The effects on embryo development and quality have not yet been investigated. The purpose of the present study was to compare the FLI medium in porcine in vitro embryo production (IVP) with our standard maturation medium (DMEM supplemented with 10 IU mL−1 PMSG and hCG, 50 ng mL−1 EGF, 100 ng mL−1 IGF1, and 5 ng mL−1 FGF). Briefly, gilt oocytes were collected via aspiration of follicles from abattoir ovaries and matured for 44 h in either FLI or standard DMEM medium at 39°C, 5% CO2 in humidified air. In vitro fertilization was performed with freshly ejaculated sperm (250,000 mL−1) of a multi-transgenic boar (GGTA1-KO/hCD46/hCD55/hCD59/hHO-1/hA20) by co-incubation with the matured oocytes in PGMTac4 medium for 4 h. Zygotes were washed twice and then cultured for 6 days in PZM3 medium. Development to the blastocyst stage was recorded at Day 6 of culture. Blastocysts were fixed and Hoechst33342 stained for counting the nuclei. Each of the experiments was repeated 3 times. In a second step, Day 5 blastocysts derived from the FLI medium were transferred to synchronized pubertal gilts to test the in vivo developmental competence of the IVF embryos. Maturation of oocytes in FLI medium resulted in a significantly higher blastocyst rate (49.3 vs. 13.5; P ≤ 0.001, Chi-squared test) and nuclei number (41.3 ± 12.2 vs. 35.3 ± 10.8; P ≤ 0.001, one-way ANOVA) compared with the standard medium, whereas the cleavage rate was not affected. Transfer of Day 5 blastocysts (average 35 embryos/recipient) derived from the FLI system using 8 recipients resulted in 7 pregnancies (87.5%) as determined by ultrasound scanning on Day 25 of gestation. At the time of writing, one recipient had delivered 5 healthy piglets after a gestation length of 114 days. Results indicate that the FLI medium significantly improves blastocyst rates and the cell number of the resulting blastocysts (Table 1) and yields pig IVF embryos with a high developmental capacity in vivo. By producing high-quality porcine embryos, this FLI-based IVF system provides an efficient method to modify the porcine genome by cytoplasmic microinjection of CRISPR/Cas molecules into IVF-derived zygotes.

Table 1.Results of maturation of oocytes in FLI medium compared with DMEM
146 Effect of pH on Rainbow trout (Oncorhynchus mykiss) Sperm Motility Using Five Extender Solutions
Authors: Peralta-Martínez M. Á. , García S. R. , Kjelland M. E. , González-Márquez H.
Published: November 2018

Rainbow trout (Oncorhynchus mykiss) sperm extender protocols can differ considerably with regards to composition of the extenders and handling. The objective of this study was to determine the effect of pH for 5 extenders on rainbow trout sperm motility and activation during storage at 5°C. Two-year-old sexually mature rainbow trout males (n = 46) weighing 1.5 to 2.5 kg were caught at Aquaculture Farm Tatakay in Jilotzingo, Estado de México, México. One semen sample per male was collected by abdominal massage. For the experiments, 100 mL of each extender (306, 512, Mounibs, Erdahl and Graham, and Hanks’ Balanced Salt Solution) was made, with pH adjusted to 6 levels (7.0, 7.2, 7.4, 7.8, 8.0, and 8.2). To evaluate pH dynamics in each extender, pH was tested daily over an 8-day storage interval. Trout sperm was added to each of the extenders in a ratio of 1:1 and motility recorded. Afterwards, each activator solution [DIA 532, saline solution (0.85%) and pond water] was added separately to a sample of the extended sperm, to initiate sperm activation. Motility was evaluated subjectively at 400× and monitored until ~99% of the sperm stopped moving (on average, in 40 s). A one-way ANOVA was used and statistical differences were set at α < 0.05. Extender 512 activated sperm motility when pH was >7.4, whereas extender 306 activated motility at every pH. Hanks’ Balanced Salt Solution activated motility at very low percentages for various pH levels, whereas Mounibs and Erdahal and Graham solutions did not activate motility for any pH tested. The 512 extender with a pH of 7 performed best (P < 0.05) as a storage solution, producing a sperm motility of 54% after activation using DIA 532. These results demonstrated the importance of evaluating effects of sperm extender pH over both short- and medium-term storage.
173 Size Matters: a Follicle-of-Origin Effect on the Preovulatory Epigenetic Constitution of Germinal Vesicle-Stage Porcine Oocytes
Authors: Heywood S. , Matheson R. L. , Thomas J. , Moley L. , Isom S. C.
Published: November 2018

The goal of this study was to evaluate global levels of a variety of histone modifications at different lysine (K) residues on Histone 3 (H3) within the chromatin of porcine germinal vesicle (GV)-stage oocytes that were aspirated from follicles of different sizes. We hypothesised that we would see evidence of a transition from open, transcriptionally active chromatin (in oocytes from smaller, growing follicles) to more closed, transcriptionally silent chromatin associated with fully grown oocytes (aspirated from large, preovulatory follicles). Cumulus-enclosed oocytes were aspirated from small (<3 mm) or large (>7 mm) follicles from abattoir-derived pig ovaries. Oocytes were denuded immediately after aspiration and then immunoprobed with antibodies specific for trimethylated (me3) H3K4, H3K9me3, and H3K27me3. Background-corrected nuclear fluorescence levels for each histone mark were collected from multiple oocytes from each of at least three experimental replicates (aspiration days). Data were subjected to one-way ANOVA with a Bonferroni multiple testing correction to determine whether there were differences in fluorescence intensities in the nuclei (germinal vesicles) of oocytes from small v. large follicles. Oocytes from large follicles displayed more intense nuclear staining for all 3 histone marks: average nuclear H3K4me3 intensity was 31.4% higher (P = 0.0004), H3K9me3 was 70.3% higher (P = 0.0218), and H3K27me3 was 32.0% higher (P = 0.0231) in oocytes from large follicles. An ancillary analysis of the data revealed no effect (P > 0.1) of pubertal status (i.e. whether small and large follicles were aspirated from pre- v. post-pubertal ovaries) on the intensity of nuclear fluorescence for any of the marks evaluated. In continuation, 3 oocytes from both follicle types were collected on each of 6 aspiration days (i.e. 18 individual oocytes from each follicle type), and the mRNA from these were used for an RT-qPCR experiment to detect the relative abundance of transcripts from 21 different genes coding for histone methyltransferase or demethylase enzymes in oocytes from large v. small follicles. Of the 21 genes tested, 5 genes (KDM4C, KDM4D, KDM5B, KDM5C, and SETD7) were not detectable in our individual oocyte samples, but transcripts from 6 of the 16 remaining genes (KDM6A, KMT2B, MLL3, SETD1B, SETDB1, and SUV39H2) were shown to be significantly more abundant in oocytes from large follicles (at least 2-fold greater abundance and P < 0.05). Although our expectation-that histone marks (and related transcripts) would consistently reflect a globally “repressive” chromatin configuration in oocytes from large follicles and a more “open” configuration in oocytes from small follicles-turned out to be untrue, the evidence suggests that the epigenetic constitution of oocytes from small follicles may indeed vary from that of oocytes from large, preovulatory follicles, and this phenomenon warrants further investigation.