bluuebunny/crossref_metadata_2025 huggingface dataset:
Landau Fermi Liquid Theory
Authors: Neilson D
Published: November 2018

This article reviews the Landau theory of interacting Fermi liquids such as mobile electrons in solids or helium-3. It starts with Landau's original formulation which takes advantage of the existence of a Fermi surface to map the strongly interacting single-particle excitations near the Fermi surface into a system of weakly interacting quasiparticle excitations. The theory relates microscopic parameters for the quasiparticle energies and scattering strengths to experimental observables. The resulting low lying collective modes of the system, such as zero sound in helium-3, are then discussed. Next the rigorous microscopic basis of the theory is presented. Finally there is an outline of a recent modification of the theory which may resolve some of the puzzles about the nature of the electron states in materials exhibiting high transition temperature superconductivity.
Density Functional Theory of Normal and Superconducting Electron Liquids: Explicit Functionals via the Gradient Expansion
Authors: Ullrich CA , Gross EKU
Published: November 2018

The basic idea of density functional theory is to map an interacting many-particle system on an effective non-interacting system in such a way that the ground-state densities of the two systems are identical. The non-interacting particles move in an effective local potential which is a functional of the density. The central task of density functional theory is to find good approximations for the density dependence of this local single-particle potential. An overview of recent advances in the construction of this potential (beyond the local-density approximation) will be given along with successful applications in quantum chemistry and solid state theory. We then turn to the extension of density functional theory to superconductors and first discuss the Hohenberg-Kohn-Sham-type existence theorems. In the superconducting analogue of the the normal-state Kohn-Sham formalism, a local single-particle potential is needed which now depends on two densities, the ordinary density n(r) and the anomalous density △(r,r/). As a first step towards the construction of such a potential, a gradient expansion technique for superconductors is presented and applied to calculate an approximation of the non-interacting kinetic energy functional Ts[n, △]. We also obtain a Thomas-Fermi-type variational equation for superconductors.
Stability of a modulated ion acoustic wave in a magnetised plasma.
Authors: Alam Md. Khurshed , Chowdhury A. Roy
Published: November 2018

A nonlinear Schrödinger equation which governs the nonlinear interaction
of the ion-acoustic wave with the quasistatic plasma slow response in a
magnetised plasma is deduced. The magnetic field is assumed to be constant. It
is observed that the coefficient of the nonlinear term in the derived
nonlinear Schrödinger equation turns out to be complex, in contrast to
the usual situation. The condition for modulational stability is derived and
it is found to be somewhat different. In the final section such a condition is
discussed graphically. Our NLS equation goes back to that of the unmagnetised
case if wc is put to zero.
Collapses and revivals of the coherence of a mesoscopic superposition of motional states.
Authors: Zheng Shi-Biao
Published: November 2018

A scheme is proposed to observe the collapses and revivals of a mesoscopic
superposition of coherent states in the motion of a trapped ion. In the scheme
the ion motion in the x-axis is first prepared in a
Schrödinger cat state, and then coupled to the motion in the
z-axis. With the vibrational excitation exchange between
the two modes, the mesoscopic quantum coherence collapses and revives
periodically, providing an example for complementarity.
The Bose-Einstein condensation of anyons.
Authors: Liu Yong
Published: November 2018

The probability for the Bose-Einstein condensation of anyons is discussed. It
is found that the ideal anyon gas near Bose statistics can display BEC
behaviour. In addition, the transition point and the specific heat are
determined.
Time Dynamics in Chaotic Many-body Systems: Can Chaos Destroy a Quantum Computer?
Authors: Flambaum V. V.
Published: November 2018

Highly excited many-particle states in quantum systems (nuclei, atoms, quantum
dots, spin systems, quantum computers) can be ‘chaotic’
superpositions of mean-field basis states (Slater determinants, products of
spin or qubit states). This is a result of the very high energy level density
of many-body states which can be easily mixed by a residual interaction
between particles. We consider the time dynamics of wave functions and
increase of entropy in such chaotic systems. As an example, we present the
time evolution in a closed quantum computer. A time scale for the entropy
S(t) increase is
t c ~τ
0 /(n log
2 n), where τ
0 is the qubit ‘lifetime’,
n is the number of qubits, S(0)
= 0 and S(t
c )=1. At t _
t c the entropy is small:
S ~nt 2
J 2 log 2
(1/t 2
J2 ), where
J is the inter-qubit interaction strength. At
t > t c
the number of ‘wrong’ states increases exponentially as 2
S(t)
. Therefore, t c may be
interpreted as a maximal time for operation of a quantum computer. At
t >>t
c the system entropy approaches that for chaotic
eigenstates.
Electron-impact ionisation of atomic hydrogen from near threshold to high energies
Authors: Bray Igor
Published: November 2018

Application of the convergent close-coupling (CCC) method to electron-impact
ionisation of the ground state of atomic hydrogen is considered at incident
energies of 15·6, 17·6, 20, 25, 27·2, 30, 54·4,
150 and 250 eV. Total through to fully differential cross sections are
presented. Following the analysis of Stelbovics (1999) the equal-energy
sharing cross sections are calculated using a solely coherent combination of
total-spin-dependent ionisation amplitudes, which are found to be simply a
factor of two greater than the incoherent combination suggested by Bray and
Fursa (1996). As a consequence, the CCC theory is particularly well-suited to
the equal-energy-sharing kinematical region, where it is able to obtain
convergent absolute scattering amplitudes, fully ab initio. This is consistent
with the step-function hypothesis of Bray (1997), and indicates that at
equal-energy-sharing the CCC amplitudes converge to half the step size.
Comparison with experiment is satisfactory in some cases and substantial
discrepancies are identified in others. The discrepancies are generally
unpredictable and some internal inconsistencies in the experimental data are
identified. Accordingly, new (e, 2e) measurements are requested.
Magnetic fields in spaces with VII0 x VIII isometries.
Authors: Dariescu Ciprian , Dariescu Marina-Aura
Published: November 2018

The aim of the present paper is to investigate some globally pathological
features of a class of static planary symmetric exact solutions with a
G6-group of motion, namely with
g44 = –sinh2
(αz), by means of the null oblique geodesics and
Penrose diagram. Finally, we derive general expressions for the
Aµ(x, y,
z)µ=1,3―
components of the vector potential, satisfying the source-free Maxwell
equations and the Lorentz condition, pointing out the influence of the global
pathological properties on the behaviour of magnetostatic fields in such
universes.
The Hydraulic Conductivity and Volumetric Elastc Modulus of Cells and Isolated Cell Walls of Nitella and Chara spp.: Pressure and Volume Effects
Authors: Zimmermann U , Steudle E
Published: November 2018

The hydraulic conductivities (L*p) and the volumetric elastic moduli (e) of N. flexilis, C. intermedia and C. fragilis were determined by means of direct cell turgor measurements. For large cell volumes (V) the function e = f(P), where P = pressure, is a hyperbola. For small cell volumes e is nearly independent of pressure and the absolute e values are smaller than those obtained for larger volumes. This volume dependence of the volumetric elastic modulus was also verified by measurements of the elastic properties of isolated cell walls of N. Jlexilis under conditions where the lengths of the cell wall tubes prepared from each cell were varied. The volume dependence of e, which is unexpected within the framework of Hooke's law, can be explained by assuming that two different intrinsic moduli e*1 and e*2 are applicable to different cell regions with volumes V*1 and V*2. The quantities e*1 and V*1 are related to the cylindrical part, and e*2 and V*2 to the small node or end regions of the internode. With this assumption the overall e is then given by:
e = (e*1e*2V)/(e*2V*1 + e*1 V*2) ? e*1e*2 V /(e*2 V + e*1 V*2) .
This indicates that for very large cells e has a saturation value equal to e*1, while for smaller volumes the influence of e*2 will become predominant. The value of e*1 was calculated to be about 7.5 x 10*7 Pa* and that of e*2 to be about 10*6 Pa. Since for small cells the overall volumetric elastic modulus e is mainly determined by e*2, the weak pressure dependence of e in such cells reflects a weak pressure dependence of e*2. On the other hand, the strong pressure dependence of e in large cells points to a strong pressure dependence of e*1. The direct determination of the elastic properties of the end regions of the internodes, which was not possible up to the present, is of great importance for growth and growth regulation.
The hydraulic conductivity of Nitella and Chara spp. was found to be independent of cell volume, but dependent on the cell turgor pressure. The L*p values were constant at high pressures, but increased on approaching the plasmolytic points. In contrast, the L*p value of the isolated cell wall of N. flexilis was constant over the whole pressure range 0-8 x 10*5 Pa and amounted to (6.9 � 1.3) x 10-*l2 ms-� Pa-�. Since the L*p value in the living N. flexilis cell increased to 4 x 10-*12 ms-� Pa-� at a pressure of 5 x 10*4 Pa it can be concluded that the cell wall becomes the rate-limiting barrier for water flow and that the hydraulic conductivity of the cell membranes must be remarkable at low pressures. The increase in L, in the low pressure range is not caused by artificial leakages or by leakages through the plasmodesmata, since no water flow across plasmodesmata could be detected.
Transport of Solutes and Water by Resetting Bladders of Utricularia
Authors: Sydenham P.H , Findlay G.P
Published: November 2018

The bladder of the insectivorous aquatic plant Utricularia, after stimulation and consequent sudden
increase in volume, slowly resets, transporting solutes, mainly Na+, K+ and C1-, and water, from the
lumen to the outside solution. The resetting process, which involves the movement of both water and
chloride against the direction of passive driving forces, requires energy. As the resetting rate is diminished
by the application of respiratory inhibitors and by lowered temperature, but is not affected
by darkness, it is clear that respiration and not photosynthesis provides the energy for transport.
Experiments with bladders resetting under paraffin oil show that the transported luminal fluid
emerges from the mouth region of the bladder.
The transport of solution from lumen to outside is essentially a one-way process. Changes of
osmotic potential in the luminal solution affect transport rate, but similar changes in the outside
solution do not. Bladders which are fully set appear to be almost completely impermeable to water.
The transport process can be accounted for as an active transport of chloride ions, with sodium
as the predominant accompanying ion, from the lumen to some intermediate region in the cellular
bladder wall. Between this region and the lumen an osmotic gradient could be set up that would
cause a passive flow of water from the lumen. An increase in hydrostatic pressure in the space could
then expel solution, possibly through a subcuticular space to the outside.
Arsenate Uncoupling of Oxidative Phosphorylation in Isolated Plant Mitochondria
Authors: Wickes W.A , Wiskish J.T
Published: November 2018

The uncoupling by arsenate of beetroot and cauliflower bud mitochondria showed the following characteristics: (1) arsenate stimulation of respiration above the rate found with phosphate; (2) inhibition of arsenate-stimulated respiration by phosphate; (3) enhancement of arsenate-stimulated respiration by ADP; (4) only partial prevention of this ADP-enhanced respiration by atractyloside; (5) inhibition by oligomycin of the arsenate-stimulated respiration back to the phosphate rate; and (6) the absence of any stimulatory effect of ADP in the presence of oligomycin. These results are qualitatively analogous to those reported for arsenate uncoupling in rat liver mitochondria.
Arsenate stimulated malate oxidation, presumably by stimulating malate entry, in both beetroot and cauliflower bud mitochondria; however, high rates of oxidation, and presumably entry, were only sustained with arsenate in beetroot mitochondria. NADH was oxidized rapidly in cauliflower bud mitochondria in the presence of arsenate, showing that arsenate did not inhibit electron transfer processes.
Proton Transport in Halobacterium haloium
Authors: Wagner G , Hope A.B
Published: November 2018

H. halobium, when cultured in media deficient in organic nutrients, showed light-dependent, transient net fluxes of H+, whose magnitude and initial direction were significantly pH-dependent. However, the extent of H+ translocation ( �H+) was almost independent of pH. Also, under these conditions, the steady-state level of bleached (A*max at 415 nm) to unbleached bacteriorhodopsin, and the rate constants to reach it, were pH-dependent.
The H+ gradient across the membrane, measured using the compound 5,5-dimethyl-2,4-oxa- zolidinedione, was 0.8 (pH outside, 7.2) or 2.55 (pH outside, 5.5) and was increased c. 0.5 units in the light. The contribution of these gradients to the total driving force for ATP synthesis is discussed.
The rigidity of the purple membrane is assumed to be influenced by the external H+ concentration, which also determines the cycling rate of bacteriorhodopsin, a light-dependent H+ carrier.
Effects of Ultraviolet Radiation on the Plasma Membranes of Chava corallina. III* Action Spectra
Authors: Doughty C.J , Hope A.B
Published: November 2018

Action spectra have been determined for the effects of 300 s of U.V. irradiation on the potential
difference and conductance of the plasmalemma in cells of C, couallina. Wavelengths for maximum
effect were 240-2.50 nm and 285 nm. The target molecules are tentatively identified as protein
molecules containing vulnerable amino acids such as cystine, since this has high photochemical
lability to 250-nm U.V. Absorption at 285 nm could be by aromatic amino acids in the same or
different proteins. A schematic model for the various u.v.-sensitive membrane properties is given,
based on the fluid mosaic model of cell membranes.
Membrane Potentials in Carrot Root Cells
Authors: Anderson W.P , Robertson R.N , Wright B.J
Published: November 2018

Membrane potentials in carrot root xylem parenchyma cells, aged for at least 5 days after excision from the parent organ, were measured under a variety of external conditions by standard intracellular electrode methods. The respiration blocking agents cyanide and carbon monoxide (in the dark) produced large (up to 90 mV) depolarizations which could be described by single exponential decay curves having rate constants (or half-times) of 0.065 s-1 (t*1/2 = 10.8 s) and 0.094 s-1 (t*1/2 = 7.4 s) respectively. The uncoupler carbonyl cyanide m-chlorophenylhydrazone caused a single exponential membrane depolarization with a rate constant of 0.0054 s-1(t*1/2 = 126 s). These effects are thought to reflect the action of an active electrogenic H+ extrusion pump at the plasmalemma.
A second, minor electrogenic transport, causing depolarization of about 10 mV in the restlng state, and due to an obligate electrogenic coupling to Cl- influx has been confirmed in KCl-pretreated tissue. In tissue pretreated in more complete nutrient solution, there is no evidence of a Cl- -coupled electrogenic exchange.
This seems to be the first report of two independent electrogenic mechanisms operating in a plant cell and, interestingly, they act in opposite senses, the major H+ extrusion causing membrane hyperpolarization, the minor Cl- -influx-coupled exchange causing depolarization, in the normal resting cell.
Stomatal Metabolism: CO2 Fixation and Respiration
Authors: Thorpe N , Milthorpe F.L
Published: November 2018

The rate of fixation of CO2 by epidermis attached to the leaf of Commelina cyanea was linear with photon flux density up to 1.08 mE m-� s-� and with CO2 concentration from 0 to 355 ppm. Detached epidermis, on the other hand, showed no response to photon flux density and had rates in the light which were only twice those in the dark. There was substantial leakage of all labelled methanol-soluble substances from isolated epidermis. Its apparent reduced functioning may well be associated with this leakage rather than reflecting transport from the mesophyll.
The early fixation products in light and dark were similar in attached and detached epidermis. These were mainly aspartate and malate in contrast to the Calvin cycle intermediates formed in mesophyll in the light. It seems likely that phosphoenolpyruvate carboxylase is closely implicated in the initial fixation of CO2 by stomata and is responsible for the much higher rates of fixation per unit of chlorophyll by epidermis than by mesophyll. Although aspartate and malate are the major products detectable after 2 min feeding with 14CO2 and remain as a high proportion of labelled products during a subsequent 12CO2 chase, amino acids, sugars and sugar phosphates together with polysaccharides and other methanol-insoluble products are eventually labelled.
Attempts to measure respiration rates of attached epidermis were unsuccessful due to fixation of mesophyll-respired CO2; the rate in detached epidermis was high, suggesting a high rate of turnover of carbon products by stomata, but we were unable to relate this to rates in attached epidermis. Rates were higher in CO2-free than in CO2-containing environments, indicating a possible explanation of the CO2 effect on stomata.
Interactions between Source, Path and Sink in Determining Phloem Translocation Rate
Authors: Lang A
Published: November 2018

Treatments involving mild (5-10 Celsius degrees) temperature changes, spanning a range of mean temperatures, were imposed upon the source, path and sink regions of a translocating plant of Nymphoides geminata whilst the translocation rate was monitored. The temperature dependence (Q*10) of the rate of translocation was evaluated for each of these treatments. A new steady rate was achieved in only 3-5 min following a temperature change and was sustained for 2 h or more. Changes in rate were propagated down the sieve tubes at speeds more than ten times greater than those of sap flow, indicating that translocation involves the flow of a slightly compressible sap.
The results suggest that translocation rate is normally under the joint control of source, path and sink regions of the plant. An attempt is made to assess their relative contributions to the overall control and this leads to the conclusion that, in this plant situation, the pathway predominates in controlling rate. It would seem that the individual rates of activity of source, path and sink regions are modulated by changes in the sieve tube sap concentration in their vicinity, these changes corresponding to, and being brought about rapidly by, changes in the hydrostatic pressure of this sap.
Effects of Microwave Energy on the Strophiole, Seed Coat and Germination of Acacia Seeds
Authors: Nguyen Tran V
Published: November 2018

Germination of Acacia longifolia and A. sophorae is enhanced by microwave energy at 2450 MHz. The technique provides a quick and effective method of treatment for seeds (either dry or moist) having an impermeable seed coat. Microwave energy causes the strophiole to appear golden and well defined under the microscope and to become permeable to water. The strophiolar fracture and the observed cracks on a treated seed coat could be explained by the thin shell theory used in structural analysis. The difference in germination rate of the two Acacias may be related to the differences in the mechanical strength of their seed coats and the way they responded to the dry and moist heat.
Osmotic Adaption in the Marine Alga Griffithsia monilis (Rhodophyceae): The Role of Ions and Organic Compounds
Authors: Bisson M.A , Kirst G.O
Published: November 2018

The red alga G. monilis maintains its turgor pressure constant at 4.05 � 0.14 x 10*5 Pa (179 measurements), or 166 mosmol/kg, over a range of external osmotic pressures from 900 to 1300 mosmol/kg. It is capable of regulating turgor pressure in the dark or when sorbitol is used to increase the external osmotic pressure. Complete regulation of turgor requires 24-36 h, although much of the regulation is accomplished in the first 2 h. The change in II*i is achieved by controlling the concentrations of K+, Na+, and Cl-. In the vacuole, KCl concentration is higher than NaCl, and KCI is usually more important than NaCl in regulating turgor, although the importance of the individual cations varies with specific conditions. The steady-state concentration of the principal photosynthetic product, digeneaside, increases with increasing external osmotic pressure. Its concentration is too low to affect the internal osmotic pressure if it is distributed evenly throughout the cell but, if it is restricted to the cytoplasm, it can play a major role in regulating the volume of the cytoplasm.
Effects of Coppicing on Growth Rates, Stomatal Characteristics and Water Relations in Eucalyptus camaldulensis Dehn
Authors: Blake T.J
Published: November 2018

Stem elongation, transpiration rate, water potential, diffusive resistance and stomatal characteristics were compared in intact and coppiced (decapitated) seedlings of E. camaldulensis. Stump sprouts from coppiced seedlings showed a threefold increase in the rate of stem elongation, a doubling in transpiration rate per seedling and a 5–8-fold increase in transpiration per unit leaf area compared with intact seedlings. Reversion to more juvenile leaf morphology following decapitation was accompanied by decrease in leaf stomatal resistance. Increased stomatal length and higher stomatal frequency on the lower surface of coppice leaves appears to explain the increased transpiration rate following decapitation compared with intact seedlings.
Factors that Influence the Yield, Stability in Culture and Cell Wall Regeneration of Spinach Mesophyll Protoplasts
Authors: Rose R.J
Published: November 2018

A study has been made of factors that influence the yield, stability in culture, and ability to regenerate
cell walls of isolated spinach (Spinacia olevacea L.) mesophyll protoplasts. The presence of 7 mM
CaZ + or 7 mM Mg2+ in the isolation medium, which also included 1.5 % (w/v) Driselase, 0.25 %
(w/v) pectinase and 0.8 M sorbitol, increased the yield and stability in culture of the protoplasts in a
liquid nutrient medium. This latter medium has been used previously in the culture of spinach leaf
discs, and does not support the division of spinach mesophyll cells. Protoplasts isolated in the presence
of CaZ+ showed a greater capacity for cell wall regeneration compared with protoplasts isolated in
the absence of ions or in the presence of Mg2+. Though darkness during culture improved the initial
protoplast stability, it inhibited wall regeneration. The initial stability of protoplasts appeared to
be dependent on plasma membrane stability, but after a few days in culture the most effective treatments
were those which stimulated cell wall regeneration. In many cases, associated with cell wall
regeneration, there was a budding off of small vesicles which sometimes contained chloroplasts.
Protoplasts isolated in the presence of Ca2+ and incubated in low light had a 50% survival rate
after 8 days culture and most had regenerated cell walls. Such culture of spinach protoplasts has
not been shown previously and should be useful in developmental studies of spinach chloroplasts.
A Distinction between the Fast and Slow Responses to Abscisic Acid
Authors: Milborrow B.V
Published: November 2018

Data already in the literature show that closure of stomata of intact leaves by abscisic acid (ABA)
occurs rapidly by the (+) enantiomer, but the (-) is ineffective. Germination and growth are
inhibited equally by (+)-ABA and (-)-ABA. The stomata in Commelina and Tropaeolum epidermal
strips have now been shown to respond to (+)-ABA but not to (-)-ABA and protein synthesis
in wheat embryos is inhibited by both. Thus the receptor sites for fast and slow responses to ABA
have different molecular requirements and the fast reaction, therefore, cannot be a prerequisite
for the slow.
Using Chlorophyll Fluorescence in vivo to Measure the Chilling Tolerances of Different Populations of Maize
Authors: Hetherington S.E , Smillie R.M , Hardacre A.K , Eagles H.A
Published: November 2018

Chlorophyll fluorescence in vivo has been used to measure the chilling tolerances of three maize
populations and their crosses as males to an inbred Corn Belt Dent tester and to investigate whether
these populations can be chill hardened. In response to chilling at O�C, the logarithm of the maximal
rate of the induced rise of chlorophyll fluorescence (FR) in leaves of the populations of Confite Puneno,
Northern Flint and U.S. Corn Belt Dent and their crosses grown at 20�C day-15�C night decreased
linearly with time. Analysis of variance of the rate of decrease of In FR showed the populations to
possess significantly different levels of chilling tolerance. Confite Puneno, a highland Peruvian maize,
was the most tolerant with a half-fall time for FR of 11 8 h. This compared with 9.4 h for the Northern
Flint population, which is better adapted to cool conditions than the U.S. Corn Belt Dent, and 8 4
h for the US. Corn Belt Dent population. In the crosses, the chilling tolerance character of the paternal
population was retained. Remeasuring plant chilling tolerance using plants grown at 16OC day-6�C
night demonstrated that all three maize populations and their crosses had become markedly chill
hardened in terms of an increase in the half-fall time for FR of leaves kept at O�C. From the results
it is suggested that chlorophyll fluorescence in vivo can be used as a rapid screening test for chilling
tolerance at the varietal level.
The Electrical Properties of Plant Cell Membranes. II.* Distortion of Non-linear Current-Voltage Characteristics induced by the Cable Properties of Chara
Authors: Smith J.R
Published: November 2018

The electrical 'cable' properties of cylindrical, radially symmetric cells with non-linear membrane
current-voltage (I-V) characteristics are considered. A numerical technique is described whereby,
from a knowledge of the membrane I-V characteristics and the cellfelectrode geometry, it is possible
to calculate the I-V characteristics that would be actually measured after distortion by the cable
properties of the cell. Thus it is shown that the I-V characteristics of charophytes such as Chara and
Nitella measured in some common experimental configurations can be significantly different from
the actual I-V characteristics of the membrane. This distortion will always tend to linearize the
measured I-V characteristics and consequently a major problem is that the magnitude of any such
linearization cannot be simply estimated. In particular if the measured conductance increases with
increasing magnitude of V, it is very difficult to determine the actual shape of the membrane I-V
characteristics. However an iterative procedure is described which will permit derivation of the correct
intrinsic membrane I-V characteristics from the distorted measured I-V characteristics, providing
that V is measured at the point of current injection. This procedure is applied to some experimental
I-V data of Chara to demonstrate the possible magnitude of the distortion arising from the cable
properties.
Glaucousness in Wheat: Its Development and Effect on Water-use Efficiency, Gas Exchange and Photosynthetic Tissue Temperatures*
Authors: Richards R.A , Rawson H.M , Johnson D.A
Published: November 2018

Glaucousness, which is the visual manifestation of epicuticular wax, has previously been found to
increase the yield of grain and dry matter of droughted wheat. This study was designed, first, to monitor
the development of epicuticular wax in a pair of durum (Triticum turgidum L. var. durum) wheats
isogenic for glaucousness and, second, to determine the likely reasons for increased yields of glaucous
durum and common (T. aestivum L.) wheats over their non-glaucous isogenic counterparts.
Glaucousness first appears on the leaf sheath at the time of stem elongation. It rapidly reaches
maximum expression, particularly on the flag leaf sheath and the abaxial surface of the flag leaf lamina,
as well as on the emerging head. In glasshouse experiments using isogenic pairs of both common and
durum wheats, the water-use efficiency measured between sowing and maturity in droughted treatments
was on average 9% higher in the glaucous lines. Glaucous leaves were retained longer than non-glaucous
leaves in the droughted treatment but not in the irrigated control. In droughted field-grown plants,
temperatures of photosynthetic tissues were up to 0.7"C cooler in glaucous than non-glaucous lines,
depending on the time of day. Similarly, in well-watered glasshouse plants, glaucous plant parts were
on average 0.3"C cooler than non-glaucous plants. Gas-exchange studies of the durum lines in both
irrigated and droughted treatments in a glasshouse indicated that ears of non-glaucous plants had higher
rates of photosynthesis and day- and night-time transpiration, a higher stomata1 conductance and a
greater rate of increase in photosynthesis with increasing light levels. However, the ratio of photosynthesis
to transpiration was higher in the ears of glaucous plants. No differences were found for flag
leaves when the adaxial surface was exposed to light. This study further documents that glaucousness
can be a yield positive character under water-limited conditions, primarily through its effect on wateruse
efficiency, on an extended period of transpiration and on the timing of the deposition of wax.
Mechanism of Paraquat Resistance in Hordeum glaucum . 11.* Paraquat Uptake and Translocation
Authors: Bishop T , Powles S.B , Cornic G
Published: November 2018

A biotype of the important and widespread annual grass weed Hordeum glaucum Steud. is resistant to
the bipyridyl herbicides. This resistance is not due to any changes at the chloroplast or protoplast level.
Experiments utilising [methyl-I4c]paraquat show no difference between leaves of susceptible and resistant
biotypes in the penetration of the cuticle by paraquat. Whole leaf photosynthesis in the resistant
biotype is dramatically less sensitive to paraquat than in the susceptible biotype. This indicates that
paraquat is sequestered in the leaf outside the cytoplasm thus preventing paraquat reaching the active
site. Translocation of [I4c]paraquat from a droplet on a leaf is negligible in the resistant biotype but
there is some translocation in the susceptible biotype. Paraquat remains localised in, or close to, the
vascular tissue when excised leaves are supplied [14C]paraquat through the transpiration stream. It is
proposed that the mechanism of resistance to paraquat is exclusion from the cytoplasm by sequestration
in the apoplast.
The Needs of Caregivers of People with COPD: A Study
Authors: Woolfe Pamela , McMillan Margaret , Conway Jane
Published: November 2018

The purpose of this research was to replicate a study undertaken with different cohorts of clients and their caregivers in both Australia and the United States of America (USA). The researcher wanted to establish better local information, through the use of a survey, about the needs of informal caregivers who provide physical and emotional care, rehabilitation and supervision of treatments for patients with Chronic Obstructive Pulmonary Disease (COPD), at home. Contemporary feedback about what caregivers perceive as critical to their ability to provide care in the home environment was identified. Health services, particularly professionals such as nurses within those services, need to respond appropriately to these needs.
Effects of corticotropin-releasing hormone and its antagonist on the gene expression of gonadotrophin-releasing hormone (GnRH) and GnRH receptor in the hypothalamus and anterior pituitary gland of follicular phase ewes
Authors: Ciechanowska Magdalena , Łapot Magdalena , Malewski Tadeusz , Mateusiak Krystyna , Misztal Tomasz , Przekop Franciszek
Published: November 2018

There is no information in the literature regarding the effect of corticotropin-releasing hormone (CRH) on genes encoding gonadotrophin-releasing hormone (GnRH) and the GnRH receptor (GnRHR) in the hypothalamus or on GnRHR gene expression in the pituitary gland in vivo. Thus, the aim of the present study was to investigate, in follicular phase ewes, the effects of prolonged, intermittent infusion of small doses of CRH or its antagonist (α-helical CRH 9-41; CRH-A) into the third cerebral ventricle on GnRH mRNA and GnRHR mRNA levels in the hypothalamo–pituitary unit and on LH secretion. Stimulation or inhibition of CRH receptors significantly decreased or increased GnRH gene expression in the hypothalamus, respectively, and led to different responses in GnRHR gene expression in discrete hypothalamic areas. For example, CRH increased GnRHR gene expression in the preoptic area, but decreased it in the hypothalamus/stalk median eminence and in the anterior pituitary gland. In addition, CRH decreased LH secretion. Blockade of CRH receptors had the opposite effect on GnRHR gene expression. The results suggest that activation of CRH receptors in the hypothalamus of follicular phase ewes can modulate the biosynthesis and release of GnRH through complex changes in the expression of GnRH and GnRHR genes in the hypothalamo–anterior pituitary unit.
The promise of dog cloning
Authors: Oh Hyun Ju , Ra Kihae , Kim Min Jung , Kim Geon A , Setyawan Erif Maha Nugraha , Lee Seok Hee , Lee Byeong Chun
Published: November 2018

Dog cloning as a concept is no longer infeasible. Starting with Snuppy, the first cloned dog in the world, somatic cell nuclear transfer (SCNT) has been continuously developed and used for diverse purposes. In this article we summarise the current method for SCNT, the normality of cloned dogs and the application of dog cloning not only for personal reasons, but also for public purposes.
Early onset of puberty in cattle: implications for gamete quality and embryo survival
Authors: Kenny D. A. , Heslin J. , Byrne C. J.
Published: November 2018

Advancing the age at which puberty and subsequent sexual maturation is attained in cattle is central to the reproductive and economic efficiency of both beef and dairy production systems worldwide. Onset of puberty in both male and female cattle is regulated by a complex network of biochemical processes and involves interaction among many key metabolic, neuroendocrine and reproductive tissues. Although our understanding of the biochemical interplay that conditions and eventually triggers the pubertal process has improved in recent years, much of the intricate mechanistic detail still eludes us. Environmental factors, such as nutritional management, as well as the genetic makeup of the animal undoubtedly affect the timing of puberty in cattle. In particular, there is now overwhelming evidence to support the importance of early life nutrition in regulating the timing of puberty in both bulls and heifers. For both genders, there is significant evidence that an improved metabolic status, early in calfhood, advances maturation of the hypothalamic–pituitary–gonadal axis, therefore facilitating earlier sexual development. Although advancing sexual maturation is a desirable goal, it is important that any strategy used does not impinge upon normal gametogenesis or postpubertal fertility potential. To this end, the aim of this review is to discuss the underlying biology of puberty in cattle with particular emphasis on the role of nutritional management during early calfhood in: (1) advancing the maturity of the hypothalamic–pituitary–gonadal axis; and (2) implications for the quality of gametes and subsequent fertility.
The mitochondrial genome: how it drives fertility
Authors: St. John Justin C. , Srirattana Kanokwan , Tsai Te-Sha , Sun Xin
Published: November 2018

In mammalian species, the mitochondrial genome is between 16.2 and 16.7 kb in size and encodes key proteins associated with the cell’s major energy-generating apparatus, the electron transfer chain. The maternally inherited mitochondrial genome has, until recently, been thought to be only involved in the production of energy. In this review, we analyse how the mitochondrial genome influences the developing embryo and cellular differentiation, as well as fetal and offspring health and wellbeing. We make specific reference to two assisted reproductive technologies, namely mitochondrial supplementation and somatic cell nuclear transfer, and how modulating the mitochondrial content in the oocyte influences embryo viability and the potential to generate enhanced offspring for livestock production purposes. We also explain why it is important to ensure that the transmission of only one population of mitochondrial (mt) DNA is maintained through to the offspring and why two populations of genetically distinct mitochondrial genomes could be deleterious. Finally, we explain how mtDNA influences chromosomal gene expression patterns in developing embryos and cells primarily by modulating DNA methylation patterns through factors associated with the citric acid cycle. These factors can then modulate the ten–eleven translocation (TET) pathway, which, in turn, determines whether a cell is in a more or less DNA methylated state.
102 In Vitro Embryo Production and Oocyte Quality in Bos indicus Beef Cows Selected for Fertility Characteristics
Authors: Vasconcelos G. L. , Maculan R. , Alves N. , Ribeiro A. L. A. P. L. , Silva A. W. B. , Cunha E. V. , Moreira G. M. , Viafara J. A. S. , Guimaraes A. S. B. , Ribeiro C. V. , Silva J. R. V. , Sales J. N. S. , Pinto T. L. C. , El Azzi M. S. , DeSouza J. C.
Published: November 2018

Embryo production may be enhanced when associated with cows selected on the basis of fertility markers, which should be easy to measure, such as antral follicle count (AFC) and genital tract morphometrics. The objective was to evaluate the effects of AFC class on oocyte 24-h outcome and in vitro embryo production in Bos indicus beef cows. Brahman (n = 151) cows (2-13 years old, 344-803 kg of BW, and 7-9 BCS). Low (LAFC), intermediate (IAFC), and high (HAFC) antral follicle classes were defined as follows: LAFC ≤ 30; IAFC 30-49; and HAFC ≥50 AFC. All follicles ≥3 mm in diameter were aspirated by conventional ovum pick-up technique. Only cumulus–oocyte complexes with at least 2 layers of granulosa cells and homogeneous cytoplasm were used for in vitro culture. They were matured in TCM-199 plus supplements for 24 h at 38.7°C in a 5% CO2 humidified atmosphere. After 24 h of maturation, a subset of oocytes (n = 319) was fixed and analysed under fluorescent microscopy and oocyte outcome was evaluated by classification, as follows: germinal vesicle (GV), germinal vesicle breakdown (GVBD), metaphase I/anaphase I/telophase I (MIAITI), and metaphase II (MII). The second subset of oocytes (n = 797) was fertilized in Ferti-TALP (10-15 oocytes per 60-µL drop) with frozen–thawed semen (18-22 h at 38.7°C in 5% CO2 after Percoll) from a single bull previously tested for good in vitro fertility. Presumptive zygotes were cultivated in CR2 medium for 48 h at 37.8°C in 5% CO2. For the remaining 96 h, embryos were transferred to 10% FCS-supplemented TCM-199 drops until the final evaluation. Data were analysed by the GENMOD, GLM, and CORR procedures of SAS (SAS Institute Inc., Cary, NC, USA). Viable oocytes, total embryos, and embryo production efficiency (viable oocyte/total embryos produced; P < 0.05) to AFC in various degrees (r2 = 0.87, 0.86, 0.30, respectively). The proportion of oocytes in GV, GVBD, MIAITI, and MII were different (P < 0.05) between LAFC, IAFC, and HAFC classes [GV: 12.3% (13/106)a, 3.1% (3/96)a and 4.3% (5/117)b, respectively]; [GVBD: 32.1% (34/106)a, 8.3% (8/96)a and 6.0 (7/117)b]; [MIAITI: 14.2% (15/106)a, 26.0% (25/96)b and 8.5% (10/117)c, respectively] and [MII: 41.5% (44/106)b, 62.5% (60/96)a and 81.2% (95/117)c, respectively). In conclusion, high AFC is positively related to better in vitro embryo fertility and to 24-h oocyte outcome after in vitro maturation.
120 Theophylline: the Key for Bulls with Low In Vitro Blastocyst Rates?
Authors: Bernal-Ulloa S. M. , Ulbrich S. E.
Published: November 2018

Although many efforts have been made to improve the sperm normal penetration ability for in vitro embryo production (IVP), sperm capacitation in bovine remains a bottleneck for in vitro fertilization (IVF). The variable responses of sperm to the different supplements in IVF medium makes the process suboptimal for every bull. Theophylline, a methylxanthine, has recently been reported to enhance and maintain in vitro blastocyst production due to prolonged motility and longevity of bovine sperm (Kang et al. 2015 J. Reprod. Dev. 61, 99-105). Here, we evaluated the effects of theophylline supplementation during IVF on developmental rates of bulls with known low and average blastocyst production under standard conditions. A total of 1498 cumulus–oocyte complexes were obtained by slicing from bovine ovaries. Cumulus-oocyte complexes were submitted to in vitro maturation (IVM) for 24 h. In vitro fertilization was performed for 19 h with (2.5 mM) or without theophylline using frozen–thawed sperm from 5 different bulls at a final sperm concentration of to 2 × 106 cells mL−1. Two of the bulls had a previous report of low blastocyst rates (A, B) and 3 showed an average blastocyst production (C, D, E). After IVF, presumptive zygotes were cultured in vitro for 8 days until the blastocyst stage. Cleavage and blastocyst rates were evaluated 3 and 8 days after IVF, respectively. R software (https://www.r-project.org/) was used to evaluate cleavage and blastocyst rates using a two-sample t-test. The supplementation of theophylline significantly increased blastocyst rates for bulls A, B, and E (Table 1; P < 0.05). The blastocyst rates did not differ for bull C and D with or without the use of theophylline (Table 1; P > 0.05). These preliminary results show that in vitro blastocyst production for low performance bulls can be improved by theophylline supplementation during IVF. The underlying mechanism probably involves phosphodiesterase (PDE) inhibition to increase intra-sperm/oocyte cAMP levels improving oocyte-sperm interaction.

Table 1.Total oocytes and mean (± SEM) cleavage and blastocyst rates of bull sperm treated or not with theophylline

The authors thank Susanne Meese and Ulrich Witschi from Swissgenetics for the cooperation and donation of frozen bull sperm.
123 In Vitro Embryo Production in Lyophilized In Vitro Culture Medium as a Method to Increase the Medium's Shelf-Life
Authors: Rubessa M. , Salerno F. , Weisgerber D. , Gasparrini B. , Harley B. , Wheeler M.
Published: November 2018

The worldwide production of livestock embryos requires stable medium with long shelf life. In this experiment, we evaluated the impact of the freeze-dried in vitro culture (IVC) medium (Mdry) on in vitro embryo production. We compared the standard IVC and Mdry media for cleavage rate and embryo production. Media solutions (10 mL) were aliquoted into 50-mL conical tubes and lyophilized to form a powder concentrate using a Genesis freeze-dryer (VirTis, Gardener, NY, USA). Lyophilization consisted of a constant cooling from 20°C to –10°C at a constant rate of 1°C/min with a 2-h hold at –10°C before sublimation at 0°C. Mdry medium were held at –80°C for 4 months. When the IVC medium was rehydrated, the pH were adjusted to 7.4. Abattoir-derived Holstein oocytes (n = 618, in 7 replicates) were in vitro matured and fertilized with sexed semen, according to standard procedures (Rubessa et al. 2011 Theriogenology 76, 1347-1355). Twenty hours after IVF, presumptive zygotes were cultured in SOF medium with 5% BS at 39°C with 5% CO2, 7% O2, and 88% N2. On Day 7, embryo yields were assessed. All recorded parameters were subjected to a Chi-Square Test 2 × 2. The parameters compared were percent cleavage, blastocysts, and embryos/cleaved. The α level was set at 0.05. All data were expressed as quadratic means and mean standard errors. The results (Table 1) showed not a statistical difference between control and Mdry. The Mdry had a higher percentage of cleaved zygotes (65.4% v. 53.4%) but not enough for a statistical difference. However, when we compared embryo production, there was no difference between treatments. The ratio between blastocysts and cleaved embryos was higher in the control group but not significant according to our selected α level. These results indicate that it is possible lyophilize IVC medium without interfering with the potential quality of the medium. Further studies will be needed to better understand the positive effect of the lyophilization on the cleavage rate.

Table 1.Mean (SD in parentheses) percentage cleavage and blastocysts
141 Antioxidant Supplementation Alleviates DNA Damage in Boar Sperm Induced by Tropical Heat Stress
Authors: Peña S. T. , Gummow B. , Parker A. J. , Paris D. B. B. P.
Published: November 2018

Seasonal heat stress is known to significantly diminish reproductive performance in pigs, particularly in the tropics, costing the industry millions in annual losses. The boar’s reduced capacity to sweat and non-pendulous scrotum, combined with the widespread use of European breeds in the tropics, makes this species particularly vulnerable to heat stress. Although heat stress is traditionally considered a sow problem, recent mouse studies demonstrate that heat stress-induced sperm DNA damage can result in arrested development and loss of early embryos. Our study investigated the impact of tropical summer heat stress on the quality and DNA integrity of boar sperm, and trialled antioxidant supplementation to alleviate the problem. Data, expressed as mean ± SEM, were analysed by one-way repeated-measures ANOVA with pairwise Bonferroni tests. Motility of sperm obtained from Large White boars (n = 5) housed in the dry tropics of Townsville, North Queensland, Australia, was characterised by computer-assisted sperm analysis but did not differ between summer, winter, or spring (total motility: 71.3 ± 8.1 v. 90.2 ± 4.2 v. 70.8 ± 5.5%, respectively; P > 0.05; progressive motility: 35.4 ± 7.0 v. 46.6 ± 4.0 v. 41.7 ± 2.8%, respectively; P > 0.05). Sperm DNA integrity in 20,000 sperm/boar per season, evaluated using TUNEL and flow cytometry, revealed 16-fold more DNA-damaged sperm in summer than winter, and nearly 9-fold more than spring (16.1 ± 4.8 v. 1.0 ± 0.2 v. 1.9 ± 0.5%, respectively; P ≤ 0.05). However, boar feed supplemented with 100 g/boar per day of proprietary custom-made antioxidants during summer significantly reduced sperm DNA damage to 9.9 ± 4.5% and 7.2 ± 1.6% (P ≤ 0.05) after 42 and 84 days of treatment respectively. Total and progressive motility were not altered by the supplement. In summary, sperm DNA integrity is compromised in boars during summer, suggesting that boar factors may contribute to seasonal embryo loss in sows. Moreover, such damage appears undetectable using traditional measures of sperm motility. Antioxidant supplementation during summer appears to mitigate the negative impact of heat stress on sperm DNA integrity.