Shoot Heterogeneity Effects on Shiraz/Richter 99 Grapevines. I. Vegetative Growth

In this study the vegetative growth parameters of normally developed and underdeveloped shoots were compared in an attempt to quantify shoot heterogeneity in a Shiraz/Richter 99 vineyard. A field trial was performed in the Stellenbosch area,Western Cape, South Africa. Comparisons based on certain vegetative growth parameters were made between normally developed and underdeveloped shoots from both shaded and well-exposed canopies. The longer primary shoots of the normally developed shoots matured earlier in the season, with less apparent competition between shoot lignification and grape ripening. Reserves were more evenly distributed in these shoots. Total starch content over the whole shoot was found to be higher in the normally developed shoots, particularly when wellexposed. More and longer secondary shoots occurred on the normally developed shoots than on the underdeveloped shoots. No difference was found in the number of primary leaves (leaves on primary shoots) betweennormally developed and underdeveloped shoots, although the leaf area was much larger in the case of the former.  Normally developed shoots had more and larger secondary leaves (leaves on secondary shoots), while all the leaves that developed in the shaded canopies were found to be larger than those in the well-exposed canopies with a higher leaf area:mass ratio. The normally developed shoots seemed to have a greater potential for producing a higher yield, with better quality, than the underdeveloped shoots, as they have a more desirable leaf area composition in addition to a larger total leaf area per shoot

Teachers' understanding and operationalisation of 'science capital'

Across the globe, governments, industry and educationalists are in agreement that more needs to be done to increase and broaden participation in post-16 science. Schools, and teachers, are seen as key in this effort. Previous research has found that engagement with science, inclination to study science, and understanding of the value of science strongly relates to a student’s science capital. This paper reports on findings from the pilot year of a one-year professional development (PD) programme designed to work with secondary school teachers to build students' science capital. The PD programme introduced teachers to the nature and importance of science capital and thereafter supported them to develop ways of implementing science capital-building pedagogy in their practice. The data comprises interviews with the participating teachers (n=10), observations of classroom practices, and analyses of the teachers' accounts of their practice. Our findings suggest that teachers found the concept of science capital to be compelling and to resonate with their own intuitive understandings and experiences. However, the ways in which the concept was operationalised in terms of the implementation of pedagogical practices varied. The difficulties inherent in the operationalisation are examined and recommendations for future work with teachers around the concept of science capital are developed

Multiple timescales for neutralization of fossil fuel CO2

The long term abiological sinks for anthropogenic CO2 will be dissolution in the oceans and chemical neutralization by reaction with carbonates and basic igneous rocks. We use a detailed ocean / sediment carbon cycle model to simulate the response of the carbonate cycle in the ocean to a range of anthropogenic CO2 release scenarios. CaCO3 will play only a secondary role in buffering the CO2 concentration of the atmosphere because CaCO3 reaction uptake capacity and kinetics are limited by the dynamics of the ocean carbon cycle. Dissolution into ocean water sequesters 70-80 of the CO2 release on a time scale of several hundred years. Chemical neutralization of CO2 by reaction with CaCO3 on the sea floor accounts for another 9-15 decrease in the atmospheric concentration on a time scale of 5.5 - 6.8 kyr. Reaction with CaCO3 on land accounts for another 3-8, with a time scale of 8.2 kyr. The final equilibrium with CaCO3 leaves 7.5-8 of the CO2 release remaining in the atmosphere. The carbonate chemistry of the oceans in contact with CaCO3 will act to buffer atmospheric CO2 at this higher concentration until the entire fossil fuel CO2 release is consumed by weathering of basic igneous rocks on a time scale of 200 kyr

Shoot Heterogeneity Effects on Shiraz/Richter 99 Grapevines. III. Leaf Chlorophyll Content

In this study, the leaf chlorophyll content of normally developed and underdeveloped shoots was compared in anattempt to quantify the effect of shoot heterogeneity in a Shiraz/Richter 99 vineyard, located in the Stellenbosch areaof the Western Cape, South Africa. Comparisons are also made between normally developed and underdevelopedshoots from shaded and well-exposed canopies. No positive correlation was found between the photosyntheticactivity and the chlorophyll concentration of the leaves at five weeks after véraison. Equal amounts of chlorophyllper cm2 and a non-significant difference in the assimilation rate were calculated for the leaves of normally developedand underdeveloped shoots. No significant differences were found between the shaded and well-exposed canopies. Ittherefore appears that it is the effective surface area per leaf or per shoot rather than the chlorophyll concentrationor activity that may be responsible for any apparent difference in the photosynthetic output of the leaves fromnormally developed and underdeveloped shoots in shaded or well-exposed canopies

Shoot Heterogeneity Effects on Shiraz/Richter 99 Grapevines. II. Physiological Activity

In this study, the physiology of normally developed and underdeveloped shoots is compared in an attempt toquantify the effect of shoot heterogeneity in a Shiraz/Richter 99 vineyard, located in the Stellenbosch area of theWestern Cape, South Africa. Comparisons are made between normally developed and underdeveloped shoots fromshaded and well-exposed canopies. In the first five weeks after véraison, photosynthetic and transpiration rates,stomatal conductance and water-use efficiency (WUE) decreased as berry ripening progressed, while the internalCO2 levels of the leaves increased. Since differences in activity between individual leaves from normally developedand underdeveloped shoots only became apparent in the third week after véraison, it seemed as if the leaf area pershoot played a more important role than the photosynthetic output per unit leaf area in determining photosynthetatesupply to the rest of the vine up to this stage. From the third week after véraison, higher levels of photosynthetateswere produced by normally developed shoots than by underdeveloped shoots, due to the larger effective leaf areaper shoot as well as the higher photosynthetic activity per unit leaf area. This points to premature senescence of theleaves on underdeveloped shoots. The quantity and quality of the yield from normally developed shoots are expectedto benefit from the higher physiological output of the leaves. The enhancing effect on leaf functioning induced bycanopy exposure became apparent from the third week after véraison

Physicochemical Properties and Catalytic Behavior of the Molecular Sieve SSZ-70

SSZ-70 is synthesized using 1,3-bis(isobutyl)imidazolium, 1,3-bis(cyclohexyl)imidazolium, and 1,3-bis(cycloheptyl)imidazolium structure directing agents (SDAs), and the solids obtained are characterized by powder X-ray diffraction (XRD), ^(29)Si magic angle spinning nuclear magnetic resonance (MAS NMR), electron microscopy, nitrogen and hydrocarbon adsorption, and thermogravimetric analyses. The physicochemical properties of SSZ-70 show that it is a new molecular sieve that has similarities to MWW-type materials. The catalytic behavior of SSZ-70 is evaluated through the use of the constraint index (CI) test. Distinct differences in the reactivity between Al-SSZ-70 and SSZ-25 (MWW) are observed and are the consequences of the structural differences between these two molecular sieves

Dynamical density functional theory for dense atomic liquids

Starting from Newton's equations of motion, we derive a dynamical density functional theory (DDFT) applicable to atomic liquids. The theory has the feature that it requires as input the Helmholtz free energy functional from equilibrium density functional theory. This means that, given a reliable equilibrium free energy functional, the correct equilibrium fluid density profile is guaranteed. We show that when the isothermal compressibility is small, the DDFT generates the correct value for the speed of sound in a dense liquid. We also interpret the theory as a dynamical equation for a coarse grained fluid density and show that the theory can be used (making further approximations) to derive the standard mode coupling theory that is used to describe the glass transition. The present theory should provide a useful starting point for describing the dynamics of inhomogeneous atomic fluids.Comment: 14 pages, accepted for publication in J. Phys.: Condens. Matte

Augmented collisional ionization via excited states in XUV cluster interactions

The impact of atomic excited states is investigated via a detailed model of laser-cluster interactions, which is applied to rare gas clusters in intense femtosecond pulses in the extreme ultraviolet (XUV). This demonstrates the potential for a two-step ionization process in laser-cluster interactions, with the resulting intermediate excited states allowing for the creation of high charge states and the rapid dissemination of laser pulse energy. The consequences of this excitation mechanism are demonstrated through simulations of recent experiments in argon clusters interacting with XUV radiation, in which this two-step process is shown to play a primary role; this is consistent with our hypothesis that XUV-cluster interactions provide a unique window into the role of excited atomic states due to the relative lack of photoionization and laser field-driven phenomena. Our analysis suggests that atomic excited states may play an important role in interactions of intense radiation with materials in a variety of wavelength regimes, including potential implications for proposed studies of single molecule imaging with intense X-rays.Comment: 4 pages, 2 figure

Generation of defects and disorder from deeply quenching a liquid to form a solid

We show how deeply quenching a liquid to temperatures where it is linearly unstable and the crystal is the equilibrium phase often produces crystalline structures with defects and disorder. As the solid phase advances into the liquid phase, the modulations in the density distribution created behind the advancing solidification front do not necessarily have a wavelength that is the same as the equilibrium crystal lattice spacing. This is because in a deep enough quench the front propagation is governed by linear processes, but the crystal lattice spacing is determined by nonlinear terms. The wavelength mismatch can result in significant disorder behind the front that may or may not persist in the latter stage dynamics. We support these observations by presenting results from dynamical density functional theory calculations for simple one- and two-component two-dimensional systems of soft core particles.Comment: 25 pages, 11 figure

Analysis of circadian pattern reveals tissue-specific alternative transcription in leptin signaling pathway

*Background*
It has been previously reported that most mammalian genes display a circadian oscillation in their baseline expression. Consequently, the phase and amplitude of each component of a signal transduction cascade has downstream consequences. 

*Results*
We report our analysis of alternative transcripts in the leptin signaling pathway which is responsible for the systemic regulation of macronutrient storage and energy balance. We focused on the circadian expression pattern of a critical component of the leptin signaling system, suppressor of cytokine signaling 3 (SOCS3). On an Affymetrix GeneChip 430A2 microarray, this gene is represented by three probe sets targeting different regions within the 3’ end of the last exon. We demonstrate that in murine brown adipose tissue two downstream 3’ probe sets experience circadian baseline oscillation in counter-phase to the upstream probe set. Such differences in expression patterns are a telltale sign of alternative splicing within the last exon of SOCS3. In contrast, all three probe sets oscillated in a common phase in murine liver and white adipose tissue. This suggests that the regulation of SOCS3 expression in brown fat is tissue specific. Another component of the signaling pathway, Janus kinase (JAK), is directly regulated by SOCS and has alternative transcript probe sets oscillating in counter-phase in a white adipose tissue specific manner.
 
*Conclusion*
We hypothesize that differential oscillation of alternative transcripts may provide a mechanism to maintain steady levels of expression in spite of circadian baseline variation