Are Botanists Becoming the Dinosaurs of Biology in the 21st Century?

The number of botany students, botany classes, botany departments in universities and botanists attending conventions has been declining over many years in North America. This is part of a general trend throughout the field of organismal biology, not just botany. The history leading up to the situation today in North America, is discussed and reasons are given for this trend over the last century of time. Seven ways to keep botany a viable occupation are discussed otherwise botany, in the 21st century, may go the way of the dinosaur. © 2007

Trends in the Composition of Consumer Expenditure: Australia 1854-1913

This paper fust surveys available evidence on consumption patterns in the period between the gold rushes and the fust world war (Section 1), then attempts to integrate this evidence to achieve a reasonably consistent set of estimates across the period (Section 2). The changes in the composition of consumption activity are then compared with those occurring since 1914 in Australia, and also with evidence for the United States and several European countries between 1875 and 1914 (Section 3). The share of food items in total consumption has declined while the shares of clothing, housing and "other" items increased between the 1850s and 1914, though this did not occur steadily across the period. Australian and U.S. consumption patterns seem broadly comparable at the end of the nineteenth century.historical analysis; income; growth rate; household

Methods of Increasing Net Work Output of Organic Rankine Cycles for Low-Grade Waste-Heat Recovery

An organic Rankine cycle (ORC) is a thermodynamic cycle that is particularly well-suited for waste heat recovery. It is generally employed for waste heat with temperatures in the range of 80 °C – 300 °C. When the application is strictly to convert waste heat into work with no restrictions on heat source exit temperature, thermal efficiency is not as relevant as other aspects of the cycle performance. In such an application, maximization of net power may be the objective rather than maximization of thermal efficiency. An air-cooled ORC for waste-heat conversion is studied in the present work. Two alternative cycle configurations which could increase the net power produced from a heat source with a given temperature and flow rate are proposed and analyzed. These cycle configurations are: • An ORC with two-phase flash expansion • An ORC with a zeotropic working fluid mixture (ZRC) A simplified ORC model is introduced which calculates the pinch point in the heat exchangers based on a specified minimum temperature difference. This model is used to assess the merits of each cycle configuration with respect to a baseline ORC when the finite capacity of the heat source and heat sink fluids is considered. The finite capacity of the heat sink fluid is incorporated into the model in terms of a condenser fan power requirement. Of all working fluids studied for the baseline ORC, R134a and R245fa result in the highest net power. The ORC with two-phase flash expansion offers the most improvement over the baseline cycle provided the expander can handle two-phase flow at the same isentropic efficiency as in the baseline case. Relative improvements are highest at low source temperatures. The maximum increase in net power is 84% over the baseline ORC when water is the working fluid at a source temperature of 80 °C. At low source temperatures, the improvements decrease with increasing condenser fan power requirements. The improvements of the ZRC are also higher for low heat source temperatures. The ZRC shows improvement between 20% and 40% over the baseline as long as the condenser fan power is not negligible. At the highest estimated condenser fan power, the ZRC shows up to 92% improvement at a source temperature of 100 °C, while the ORC with flash expansion is no longer beneficial. This work represents a first step toward identifying a more optimal ORC configuration for waste heat recovery. Other data, including experimental validation, operating experience, and economic analysis particular to an application will be required to support a final recommendation

Spreading of Latex Particles on a Substrate

We have investigated both experimentally and theoretically the spreading behavior of latex particles deposited on solid substrates. These particles, which are composed of cross-linked polymer chains, have an intrinsic elastic modulus. We show that the elasticity must be considered to account for the observed contact angle between the particle and the solid substrate, as measured through atomic force microscopy techniques. In particular, the work of adhesion computed within our model can be significantly larger than that from the classical Dupr\'{e} formula.Comment: 7 pages, 7 figures, to appear in Europhys. Let

Thermodynamic Comparison of Organic Rankine Cycles Employing Liquid-Flooded Expansion or a Solution Circuit

Two modifications to a conventional Organic Rankine Cycle (ORC) are investigated: an Organic Rankine Cycle with Liquid-Flooded Expansion (ORCLFE), and an Organic Rankine Cycle with Solution Circuit (ORCSC). The ORCLFE involves “flooding” the expansion device with a liquid that is in thermal equilibrium with the primary working fluid, while simultaneously expanding the primary working fluid through the same device. The ORCSC employs a zeotropic mixture consisting of two components with a large boiling point difference. The more volatile component in the vapor phase is separated from the absorbent in the liquid phase; the vapor then flows through the expansion device, whereas the liquid absorbent gives rise to a regenerative solution circuit. A thermodynamic model is used to compare these modified ORCs with conventional ORC technology for a range of working fluids including ammonia, water, CO2, acetone, pentane, R134a and R245fa. The working fluid pairs considered for the ORCSC are ammoniaewater and CO2eacetone. Based purely on thermodynamic considerations, the conventional ORC using water as the working fluid is found to be more efficient than ORCs that use other working fluids. It yields almost 65% of the Carnot efficiency for a source and sink temperature of 200C and 20C, respectively. However, the use of water requires low expander exhaust quality, large pressure ratios, and a large expander due to its low density at the expander exhaust. Thus, the practical challenges of using water as a working fluid at typical ORC input temperatures may make its use prohibitive. The ORCLFE always leads to improved cycle efficiency when compared to an ORC for a given working fluid, but it requires the use of a positive displacement expander. The ORCSC shows the lowest efficiencies for the working fluid pairs studied. There are significant practical advantages intrinsic to both the ORCLFE and the ORCSC. For example, the more isothermal expansion of the ORCLFE eliminates the concern of low expander exhaust quality for wet working fluids. The ORCSC provides the ability to use the two-phase temperature glide to match source and sink temperature profiles, facilitates intrinsic capacity control, and can have significantly lower working pressures than an ORC. Ultimately, the overall best choice of cycle and working fluid is highly application-specific and should balance the tradeoffs between efficiency and practical concerns. The thermodynamic analysis presented in this work represents a step toward identifying an optimal ORC solution for an application where the temperature glides of the source and sink fluids are sufficiently small to approximate a thermal energy reservoir

Multi-scale three-dimensional characterization of iron particles in dusty olivine: Implications for paleomagnetism of chondritic meteorites

Dusty olivine (olivine containing multiple sub-micrometer inclusions of metallic iron) in chondritic meteorites is considered an ideal carrier of paleomagnetic remanence, capable of maintaining a faithful record of pre-accretionary magnetization acquired during chondrule formation. Here we show how the magnetic architecture of a single dusty olivine grain from the Semarkona LL3.0 ordinary chondrite meteorite can be fully characterised in three dimensions, using a combination of Focussed-Ion-Beam nanotomography (FIB-nT), electron tomography and finite-element micromagnetic modelling. We present a three-dimensional (3D) volume reconstruction of a dusty olivine grain, obtained by selective milling through a region of interest in a series of sequential 20 nm slices, which are then imaged using scanning electron microscopy. The data provide a quantitative description of the iron particle ensemble, including the distribution of particle sizes, shapes, interparticle spacings and orientations. Iron particles are predominantly oblate ellipsoids with average radii 242 ± 94 nm by 199 ± 80 nm by 123 ± 58 nm. Using analytical TEM we observe that the particles nucleate on sub-grain boundaries and are loosely arranged in a series of sheets parallel to (001) of the olivine host. This is in agreement with the orientation data collected using the FIB-nT, and highlights how the underlying texture of the dusty olivine is crystallographically constrained by the olivine host. The shortest dimension of the particles is oriented normal to the sheets and their longest dimension is preferentially aligned within the sheets. Individual particle geometries are converted to a finite-element mesh and used to perform micromagnetic simulations. The majority of particles adopt a single vortex state, with ‘bulk’ spins that rotate around a central vortex core. We observed no particles, which are in a true single domain state. The results of the micromagnetic simulations challenge some pre-conceived ideas about the remanence carrying properties of vortex states. There is often not a simple predictive relationship between the major, intermediate and minor axes of the particles and the remanence vector imparted in different fields. Although the orientation of the vortex core is determined largely by the ellipsoidal geometry (i.e., parallel to the major axis for prolate ellipsoids and parallel to the minor axis for oblate ellipsoids), the core and remanence vectors can sometimes lie at very large (tens of degree) angles to the principal axes. The subtle details of the morphology can control the overall remanence state, leading in some cases to a dominant contribution from the bulk spins to the net remanence, with profound implications for predicting the anisotropy of the sample. The particles have very high switching fields (several hundred mT), demonstrating their high stability and suitability for paleointensity studies.The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC grant agreements 291522-3DIMAGE (P.A.M.) and 320750 - Nanopaleomagnetism (J.F.E., R.J.H., and P.A.M.). BPW and RRF were supported by NASA Emerging Worlds program grant #NNX15AH72G, the NASA Solar System Exploration and Research Virtual Institute grant #NNA14AB01A, and a generous gift from Thomas F. Peterson, Jr. The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement No. 320832-Imagine. (W.W . and P.O.C.) W.W. was also supported for this research under NERC grant NE/J020966/1 - Predicting the reliability with which the geomagnetic field can be recorded in igneous rocks.This is the author accepted manuscript. It is currently under an indefinite embargo pending publication by the Mineralogical Society of America

Vertical zonation of testate amoebae in the Elatia Mires, northern Greece : palaeoecological evidence for a wetland response to recent climate change or autogenic processes?

The Elatia Mires of northern Greece are unique ecosystems of high conservation value. The mires are climatically marginal and may be sensitive to changing hydroclimate, while northern Greece has experienced a significant increase in aridity since the late twentieth century. To investigate the impact of recent climatic change on the hydrology of the mires, the palaeoecological record was investigated from three near-surface monoliths extracted from two sites. Testate amoebae were analysed as sensitive indicators of hydrology. Results were interpreted using transfer function models to provide quantitative reconstructions of changing water table depth and pH. AMS radiocarbon dates and 210Pb suggest the peats were deposited within the last c. 50 years, but do not allow a secure chronology to be established. Results from all three profiles show a distinct shift towards a more xerophilic community particularly noted by increases in Euglypha species. Transfer function results infer a distinct lowering of water tables in this period. A hydrological response to recent climate change is a tenable hypothesis to explain this change; however other possible explanations include selective test decay, vertical zonation of living amoebae, ombrotrophication and local hydrological change. It is suggested that a peatland response to climatic change is the most probable hypothesis, showing the sensitivity of marginal peatlands to recent climatic change

Synthesis and biological evaluation of N-cyanoalkyl-, Naminoalkyl-, and N-guanidinoalkyl-substituted 4-aminoquinoline derivatives as potent, selective, brain permeable antitrypanosomal agents

YesCurrent drugs against human African trypanosomiasis (HAT) suffer from several serious drawbacks. The search for novel, effective, brain permeable, safe, and inexpensive antitrypanosomal compounds is therefore an urgent need. We have recently reported that the 4-aminoquinoline derivative huprine Y, developed in our group as an anticholinesterasic agent, exhibits a submicromolar potency against Trypanosoma brucei and that its homo- and hetero-dimerization can result in to up to three-fold increased potency and selectivity. As an alternative strategy towards more potent smaller molecule anti-HAT agents, we have explored the introduction of ω-cyanoalkyl, ω-aminoalkyl, or ω-guanidinoalkyl chains at the primary amino group of huprine or the simplified 4-aminoquinoline analogue tacrine. Here, we describe the evaluation of a small in-house library and a second generation of newly synthesized derivatives, which has led to the identification of 13 side chain modified 4-aminoquinoline derivatives with submicromolar potencies against T. brucei. Among these compounds, the guanidinononyltacrine analogue 15e exhibits a 5-fold increased antitrypanosomal potency, 10-fold increased selectivity, and 100-fold decreased anticholinesterasic activity relative to the parent huprine Y. Its biological profile, lower molecular weight relative to dimeric compounds, reduced lipophilicity, and ease of synthesis, make it an interesting anti-HAT lead, amenable to further optimization to eliminate its remaining anticholinesterasic activity.Wellcome Trus

Sensory cutaneous papillae in the sea lamprey (Petromyzonmarinus L.) : I. Neuroanatomy and physiology

Molecules present in an animal's environment can indicate the presence of predators,food, or sexual partners and consequently, induce migratory, reproductive, foraging,or escape behaviors. Three sensory systems, the olfactory, gustatory, and solitarychemosensory cell (SCC) systems detect chemical stimuli in vertebrates. While agreat deal of research has focused on the olfactory and gustatory system over theyears, it is only recently that significant attention has been devoted to the SCC sys-tem. The SCCs are microvillous cells that were first discovered on the skin of fish,and later in amphibians, reptiles, and mammals. Lampreys also possess SCCs that areparticularly numerous on cutaneous papillae. However, little is known regarding theirprecise distribution, innervation, and function. Here, we show that sea lampreys(Petromyzon marinus L.) have cutaneous papillae located around the oral disk, nostril,gill pores, and on the dorsal fins and that SCCs are particularly numerous on thesepapillae. Tract-tracing experiments demonstrated that the oral and nasal papillae areinnervated by the trigeminal nerve, the gill pore papillae are innervated by branchialnerves, and the dorsal fin papillae are innervated by spinal nerves. We also character-ized the response profile of gill pore papillae to some chemicals and showed thattrout-derived chemicals, amino acids, and a bile acid produced potent responses.Together with a companion study (Suntres et al., Journal of Comparative Neurology,this issue), our results provide new insights on the function and evolution of the SCCsystem in vertebrates