bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical evaluation of soft inter‐slab joint in concrete‐faced rockfill dam with dual mortar finite element method
Authors: Zhou Mozhen , Zhang Bingyin , Peng Chong
Published: January 2018

Recently constructed concrete‐faced rockfill dams (CFRDs) often use soft inter‐slab joints to prevent axial compression‐induced extrusion damage in the concrete face. Due to the complexity of the multibody contact and the lack of information on the actual behavior of soft joints, it is highly challenging to numerically assess the effect of soft joints in CFRDs. In this paper, we present a numerical approach for the three‐dimensional modeling of CFRDs with hard and soft joints. A dual mortar finite element method with Lagrange multiplier is developed to treat the multibody contact in hard joints with impenetrability condition. The soft joint slab‐filler‐slab contact system is modeled using an equivalent contact interface approach, where the soft contact constraints are imposed using a perturbed Lagrange formulation. Through a series of laboratory tests, the mechanical behavior of soft joint is investigated. An extrusion model for the soft joint is presented and implemented in the dual mortar finite element method. The proposed numerical method is applied to the three‐dimensional analysis of Tianshengqiao‐1 CFRD. Despite the complex multibody contact and strong material and geometry nonlinearities in the CFRD, the proposed method is stable and capable of capturing salient characteristics of the CFRD. Numerical results show that in Tianshengqiao‐1, the employment of soft joints can effectively reduce the axial compression stress, thus greatly alleviating the risk of extrusion damage in the concrete face.
Synthesis, characterization, thermal, dynamic mechanical, and dielectric studies of Ba0.7Sr0.3TiO3/polystyrene composites
Authors: Shalu Saumya , Kar Pradip , Krupka Jerzy , Dasgupta Ghosh Barnali
Published: January 2018

Ba0.7Sr0.3TiO3/polystyrene composite films were successfully prepared through solution casting route and characterized by SEM and XRD. The particle size distribution of sol‐gel synthesized Ba0.7Sr0.3TiO3 filler was analyzed by dynamic light scattering. The Z‐average size of Ba0.7Sr0.3TiO3 particles is 314.78 nm (∼0.3 µm). At low concentrations of the filler there is no significant agglomeration between the particles whereas at higher concentrations of the filler (∼40 vol%) agglomerates were observed in the composite film as evidenced by scanning electron microscopy. The thermal and dynamic mechanical properties of the synthesized composites were studied in detail that show the 30 vol% Ba0.7Sr0.3TiO3/PS to be the most effective composite. The dielectric properties of Ba0.7Sr0.3TiO3/PS composites as a function of the filler content in the polymer matrix in the range 10 Hz to 1 MHz and at 5 GHz along with temperature dependent dielectric studies for 30 vol% and 50 vol% Ba0.7Sr0.3TiO3/PS composites at 10 kHz and 1 MHz have been reported. The dielectric constant for 50 vol% Ba0.7Sr0.3TiO3/PS composite at 5 GHz is 10.34 which is higher than reported literature values for similar polystyrene composites with other fillers. Different theoretical models were employed to predict the effective permittivity of the composites and compared with the experimental results. POLYM. COMPOS., 39:E1714–E1724, 2018. © 2018 Society of Plastics Engineers
Simulation of the effect of an external GHz electric field on the potential energy profile of Ca2+ ions in the selectivity filter of the CaVAb channel
Authors: Adiban Jamal , Jamali Yousef , Rafii‐Tabar Hashem
Published: January 2018

CaV channels are transmembrane proteins that mediate and regulate ion fluxes across cell membranes, and they are activated in response to action potentials to allow Ca2+ influx. Since ion channels are composed of charge or polar groups, an external alternating electric field may affect the ion‐selective membrane transport and the performance of the channel. In this article, we have investigated the effect of an external GHz electric field on the dynamics of calcium ions in the selectivity filter of the CaVAb channel. Molecular dynamics (MD) simulations and the potential of mean force (PMF) calculations were carried out, via the umbrella sampling method, to determine the free energy profile of Ca2+ ions in the CaVAb channels in presence and absence of an external field. Exposing CaVAb channel to 1, 2, 3, 4, and 5 GHz electric fields increases the depth of the potential energy well and this may result in an increase in the affinity and strength of Ca2+ ions to binding sites in the selectivity filter the channel. This increase of strength of Ca2+ ions binding in the selectivity filter may interrupt the mechanism of Ca2+ ion conduction, and leads to a reduction of Ca2+ ion permeation through the CaVAb channel.
Patterning Graphene Surfaces with Iron‐Oxide‐Embedded Mesoporous Polypyrrole and Derived N‐Doped Carbon of Tunable Pore Size
Authors: Zhu Shuyan , Tian Hao , Wang Nan , Chen Bin , Mai Yiyong , Feng Xinliang
Published: January 2018

This study develops a novel strategy, based on block copolymer self‐assembly in solution, for preparing two‐dimensional (2D) graphene‐based mesoporous nanohybrids with well‐defined large pores of tunable sizes, by employing polystyrene‐block‐poly(ethylene oxide) (PS‐b‐PEO) spherical micelles as the pore‐creating template. The resultant 2D nanohybrids possess a sandwich‐like structure with Fe2O3 nanoparticle‐embedded mesoporous polypyrrole (PPy) monolayers grown on both sides of reduced graphene oxide (rGO) nanosheets (denoted as mPPy‐Fe2O3@rGO). Serving as supercapacitor electrode materials, the 2D ternary nanohybrids exhibit controllable capacitive performance depending on the pore size, with high capacitance (up to 1006 F/g at 1 A/g), good rate performance (750 F/g at 20 A/g) and excellent cycling stability. Furthermore, the pyrolysis of mPPy‐Fe2O3@rGO at 800 °C yields 2D sandwich‐like mesoporous nitrogen‐doped carbon/Fe3O4/rGO (mNC‐Fe3O4@rGO). The mNC‐Fe3O4@rGO nanohybrids with a mean pore size of 12 nm show excellent electrocatalytic activity as an oxygen reduction reaction (ORR) catalyst with a four‐electron transfer nature, a high half‐wave‐potential of +0.84 V and a limiting current density of 5.7 mA/cm2, which are well comparable with those of the best commercial Pt/C catalyst. This study takes advantage of block copolymer self‐assembly for the synthesis of 2D multifunctional mesoporous nanohybrids, and helps to understand the control of their structures and electrochemical performance.
Fluorescent Diarylethene Photoswitches—A Universal Tool for Super‐Resolution Microscopy in Nanostructured Materials
Authors: Nevskyi Oleksii , Sysoiev Dmytro , Dreier Jes , Stein Simon Christoph , Oppermann Alex , Lemken Florian , Janke Tobias , Enderlein Jörg , Testa Ilaria , Huhn Thomas , Wöll Dominik
Published: January 2018

Super‐resolution fluorescence microscopy allows for unprecedented in situ visualization of biological structures, but its application to materials science has so far been comparatively limited. One of the main reasons is the lack of powerful dyes that allow for labeling and photoswitching in materials science systems. In this study it is shown that appropriate substitution of diarylethenes bearing a fluorescent closed and dark open form paves the way for imaging nanostructured materials with three of the most popular super‐resolution fluorescence microscopy methods that are based on different concepts to achieve imaging beyond the diffraction limit of light. The key to obtain optimal resolution lies in a proper control over the photochemistry of the photoswitches and its adaption to the system to be imaged. It is hoped that the present work will provide researchers with a guide to choose the best photoswitch derivative for super‐resolution microscopy in materials science, just like the correct choice of a Swiss Army Knife's tool is essential to fulfill a given task.
Assessing the Influence of Tilapia on Sport Fish Species in North Carolina Reservoirs
Authors: Henson Mary Nell , Derek Aday D. , Rice James A. , Layman Craig A.
Published: January 2018

Redbelly Tilapia Tilapia zilli and Blue Tilapia Oreochromus aureus are indigenous to Africa and the Middle East, but now occur throughout the southeastern United States. It is fairly well understood that foraging flexibility and wide salinity, oxygen, and temperature tolerances have led to general invasion success for most tilapia species. Conflicting empirical information about the influence of tilapia on native sport fish species, however, leaves natural resource managers unable to anticipate and prevent further introductions and potential associated risks to native sport fishes. This investigation focused on two North Carolina reservoirs with tilapia populations: Hyco Lake, a large reservoir in northcentral North Carolina and Lake Julian, a small impoundment in western North Carolina. These reservoirs receive heated effluent from power generation, which is assumed to provide winter refuge for tilapia at a time when temperatures would otherwise lead to mortality. We assessed relative abundances of the tilapias and native sport species (Bluegill Lepomis macrochirus, black basses Micropterus spp., and Black Crappie Pomoxis nigromaculatus) in these systems and examined their trophic interactions via diet and stable isotope analyses in both lakes. In Hyco Lake we assessed potential spatial interactions and influences on relative abundance using a priori candidate models and model selection via Akaike's information criterion (AIC). These analyses indicated little evidence of tilapias influencing the relative abundances of the sport species in Hyco Lake. In both lakes, however, we did find substantial diet overlap between the tilapias and Bluegill along with isotopic niche overlap between Blue Tilapia and Bluegill in Lake Julian and Redbelly Tilapia and Bluegill in Hyco Lake. Due to the omnivorous and flexible diet of all three species these interactions were not surprising, but the ultimate influence on Bluegill growth and size structure is unknown. Overall, our results suggest that tilapia are exploiting trophic niches that are not used by the sport fishes of interest in these two very different reservoir systems and that their direct impact on sport species is not substantial.
The Apple Falls Increasingly Far: Parent-Child Correlation in Schooling and the Growth of Post-Secondary Education in Switzerland
Authors: Cattaneo Alejandra , Hanslin Sandra , Winkelmann Rainer
Published: January 2018

We analyze the completed highest education degree of four ten-year birth cohorts between 1934 and 1973 in Switzerland, using data from the Swiss Household Panel 1999–2004. As expected, the fraction of tertiary graduates has increased over time, for women more so than for men. Educational attainment is highly correlated with educational attainment of parents. We then decompose the overall trend into a parental background effect and a general expansion effect. For women in particular, we find that a substantial fraction of the overall increase in participation in tertiary education can be explained by the fact that the participation rates of women with lowly educated parents have increased. We furthermore explore the role of financial constraints in explaining these trends. Although the number of individuals suffering financial hardship during youth has declined over time, logit models suggest that financial problems might have become more important as an impediment for higher education.
Life Cycle Portfolio Choice: A Swiss Perspective
Authors: Zainhofer Florian
Published: January 2018

We use panel data from the Swiss Labor Force Survey to estimate age-earnings profiles as well as transitory and permanent income shock variances for investor groups distinguished by gender, education and activity rate. Estimation results are then used to stylize several different Swiss investor types. Finally, we determine optimal life cycle consumption, savings and risky asset share for these investor types using a recent computational life cycle model of portfolio choice suggested by Cocco et al. (2005). We are particularly interested in the allocation differences between the investor types and their normative implications.
Modeling Monetary Transmission in Switzerland with a Structural Cointegrated VAR Model
Authors: Assenmacher-Wesche Katrin
Published: January 2018

This paper examines the transmission of monetary policy in Switzerland using a structural cointegrated VAR model that includes real money, real output, a long and short-term interest rate, inflation, the exchange rate and a foreign interest rate as endogenous variables and oil prices as exogenous variables. The model takes account of five cointegrating relations that are interpreted as money demand, the real interest rate, the term spread, uncovered interest parity and an aggregate demand schedule. Recursive analysis confirms that the model remains stable after the adoption of a new monetary policy framework of the Swiss National Bank in 2000. After identifying a monetary policy shock, the model is used for impulse-response analysis. We obtain plausible responses of inflation and output to a monetary policy shock but despite the inclusion of money and oil prices an exchange rate puzzle remains present.
Estimation of Hedonic Models Using a Multilevel Approach: An Application for the Swiss Rental Market
Authors: Djurdjevic Dragana , Eugster Christine , Haase Ronny
Published: January 2018

This paper is an empirical application of a hedonic model to determine rents in Switzerland. Unlike traditional hedonic models, we take account of the fact that data are clustered at different levels. The resulting spatial autocorrelation and heterogeneity permits a consideration of different submarkets within Switzerland. For the empirical analysis, we consider the special case of the clustering of apartments at municipality level. Our results show that even after controlling for housing and locational attributes, a significant part of rental differences are still attributable to municipality differences.
The Swiss Franc exchange rate and deviations from uncovered interest parity: Global vs domestic factors
Authors: Hoffmann Mathias , Suter Rahel
Published: January 2018

We examine the role of global and country-specific factors for the Swiss franc exchange rate in the period 1990–2009. Simple asset pricing theory would predict that exchange rates reflect relative movements in national discount factors and that systematic departures from uncovered interest parity can only be explained by international differences in the exposure to the common (global) component of all national discount factors. We extend the methodology of Lustig, Roussanov and Verdelhan (2009) to allow individual currencies’ exposure to this global factor to vary over time as a function of the interest rate differential. This allows us to study the time-varying risk characteristics of individual currency pairs. We find that the Swiss franc acts as a safe haven against some currencies — notably for dollar-based investors — but not for all, specifically not the euro. Also, the extent to which global factors have weighed on the Swiss franc exchange rate has varied over the sample period and appears more subdued in the global low interest rate environment of the last decade.
International policy coordination and simple monetary policy rules
Authors: Berger Wolfram
Published: January 2018

This paper studies monetary policy in an optimizing two-country model. We suppose a two-step production process that is associated with vertical trade. Prices of final consumption goods are sticky and pass-through can be incomplete. Monetary authorities should respond to both home and foreign shocks in this set-up. Which simple, i.e. non-optimal, targeting rule best supports the welfare maximizing policy hinges critically on the degree of the cross-country interdependence in production and the relative importance of productivity and cost-push shocks. We argue that the relative volatility of productivity and cost-push shocks determines whether the monetary authority should follow a price targeting rule whereas the degree of vertical integration determines which simple price targeting rule (producer or consumer price index targeting) is best.
Productivity and economic growth in Switzerland 1991–2006
Authors: Rudolf Barbara , Zurlinden Mathias
Published: January 2018

In this paper, we analyse the sources of economic growth in Switzerland during the period 1991–2006. The results suggest that labour input and capital input contribute 0.52 pp and 0.57 pp, respectively, to the average annual GDP growth of 1.44%. The remaining 0.35 pp represent growth in multi-factor productivity which is calculated as a residual. The estimate of growth in multi-factor productivity is lower than in previous studies because our measure of labour input takes changes in labour quality into account. Changes in labour quality explain 0.39 pp of the 0.52 pp contribution from labour input.
Application of the Swiss fiscal rule to artificial data a Monte Carlo simulation
Authors: Geier Alain
Published: January 2018

The Swiss fiscal rule or “debt brake” is applied to simulated data of economic output and fiscal revenues. The budget remains almost perfectly balanced and the debt ratio stable over the medium and long term: The cyclical adjustment of the debt brake is effective in terms of its primary objective of achieving a balanced budget over the medium term. The rule also performs well with respect to the objective of taking into account the position of the economy in the cycle. In the case of a non-stationary GDP series, however, this result can not be guaranteed anymore.
Swiss Energy Strategies under Global Climate Change and Nuclear Policy Uncertainty
Authors: Marcucci Adriana , Turton Hal
Published: January 2018

Domestic strategies for the Swiss energy system are likely to be affected by a range of uncertain global challenges, such as natural resource availability and depletion, international climate change policies, and global technology policies. We analyze technological choices for Switzerland under a stringent global climate policy with modest global energy resources; and the possible consequences of different global or regional policies in response to the recent nuclear accident in Fukushima, Japan. We use MERGE, an integrated assessment model, with a division of the world in 10 regions, including Switzerland and Japan. We find that nuclear energy, including light water reactors or more advanced technologies have the potential to play a major role in the future energy system. The consequences of a moratorium on the construction of new nuclear power plants include the need for additional electricity efficiency measures and the integration of a large share of intermittent renewables, raising additional challenges.
Exchange rates and import prices in Switzerland
Authors: Herger Nils
Published: January 2018

For the case of Switzerland, this paper endeavours to estimate the empirical extent to which exchange rates are “passed-through” onto import prices. For data covering the 1999 to 2010 period, the results suggest that (i) on aggregate, the exchange rate pass-through is highly incomplete with an elasticity of around 0.3 and (ii) major differences arise between industries. In particular, larger pass-through effects can be observed for certain commodities and other standardised products such as paper, timber, or minerals whilst for automobiles and textiles, the impact of the exchange rate upon import prices is almost always negligible and statistically far from significant.
Can green power save us from climate change?
Authors: Taylor M. Scott
Published: January 2018

International efforts to lower emissions have largely failed, and many now believe we will fail to limit warming to less than 2 degrees Celsius by 2100. In this extended abstract, I discuss whether a wholesale movement to renewable energy or Green Power could limit carbon emissions to meet a 2 degree Celsius target while simultaneously meeting the world’s growing demands for energy. Using a very simple growth model I calculate the burden Green Power must carry in order to keep emissions within the 2 degree target, and then discuss the speed, scope, and size of the energy transition this would imply. An energy transition of sufficient speed and magnitude to meet these targets is unlikely, leading me to believe that Green Power cannot save us from climate change.
Obtaining and Predicting the Bounds of Realized Correlations
Authors: Grossmass Lidan
Published: January 2018

This paper argues that the inherent data problems make precise point identification of realized correlation difficult but identification bounds in the spirit ofManski(1995) can be derived. These identification bounds allow for a more robust approach to inference especially when the realized correlation is used for estimating other risk measures. We forecast the identification bounds using the HAR model ofCorsi(2003) using data during the year of onset of the credit crisis and find that the bounds provide good predictive coverage of the realized correlation for both 1- and 10-step forecasts even in volatile periods.
Review of accelerator driven heavy ion nuclear fusion
Authors: Hofmann Ingo
Published: January 2018

Using high energy accelerators for energy production by nuclear fission goes back to the 1950's with plans for “breeder accelerators” as well as with early ideas on subcritical reactors, which are currently pursued in China and other countries. Also, fusion came in, when the idea emerged in the mid 1970's to use accelerators and their highly time and space compressed beams in order to generate the extremely high density and temperatures required for inertial fusion energy production. Due to the higher repetition rates and efficiencies of accelerators, this was seen as a promising alternative to using high power lasers. After an introduction to nuclear fission applications of accelerators, this review summarizes some of the scientific developments directed towards this challenging application – with focus on the European HIDIF-study- and outlines parameters of future high energy density experiments after construction of the FAIR/Germany and HIAF/China heavy ion accelerator projects.
Helicopter Mountain Rescue in Slovenia from 2011 to 2015
Authors: Deeb Janina Golob , Walter Nicholas , Carrico Caroline , Gašperin Miha , Deeb George R.
Published: January 2018

Introduction

The popularity of adventure recreation in wilderness areas across the world continues to increase. Nevertheless, the risk of injury and illness remains significant. The purpose of this study is to analyze the mountain rescue operations performed in Slovenia between 2011 and 2015.

Methods

This retrospective study reports mountain rescue operations documented by the Slovenian National Mountain Rescue Association. The annual number of ground-based and helicopter-based rescues were identified and compared. For 2015, the indication for rescue and the severity of injury were also analyzed, specifically for interventions requiring the use of a helicopter.

Results

From 2011 through 2015, the number of rescues remained consistent with an annual average of 413 (SD ±15; range, 393–434) rescues. However, the percentage of ground-based rescues varied significantly year by year ( P=0.016), with highest rate in 2014 (68%) and the lowest in 2015 (56%). In 2015, 434 mountain rescue operations were reported in Slovenia. Injury accounted for 44%, illness for 10%, and fatality for 9% of the rescues. In 37%, no illness or injury was reported. Helicopter rescue was used in 190 (44%) of all interventions. Among the 190 helicopter rescues, 49% of patients had nonfatal injuries, 29% required no medical treatment, 15% had illness, and 7% had fatal injuries.

Conclusions

A significant number of mountain rescue operations were conducted in Slovenia from 2011 through 2015. Most of these were needed for injured, ill, or deceased persons. A notable number of rescues in 2015 required a helicopter.
The President's Power to Withdraw the United States from International Agreements at Present and in the Future
Authors: Galbraith Jean
Published: January 2018

An uneasy equilibrium exists with respect to how the United States exits international agreements. In general, exit is easy as a matter of legal doctrine but, for important agreements, difficult as a matter of political practice. While presidents can withdraw the United States from most major international agreements, they have done so only rarely—and never yet with deep costs to the stability of our world order.
Associations between alcohol and obesity in more than 100 000 adults in England and Scotland
Authors: O’Donovan Gary , Stamatakis Emmanuel , Hamer Mark
Published: January 2018

The objective of this cross-sectional study was to clarify the association between alcohol and obesity using data from 106 182 adults in England and Scotland (46·7 % male; mean 46·9 (sd 16·9) years). Trained interviewers asked participants about alcohol intake. Obesity was defined as BMI≥30 kg/m2. Potential confounders included age, sex, smoking, physical activity, longstanding illness, psychological distress and socioeconomic status. Compared with those who drank at least five times a week, obesity risk was 1·21 (95 % CI 1·15, 1·27) in those who drank one to four times a week, 1·53 (95 % CI 1·43, 1·62) in those who drank one to two times a month, 1·61 (95 % CI 1·52, 1·71) in those who drank less than once every couple of months, 1·34 (95 % CI 1·23, 1·47) in those who were former drinkers, and 1·03 (95 % CI 0·95, 1·11) in those who were never drinkers. Compared with those who drank a harmful volume, obesity risk was 0·78 (95 % CI 0·68, 0·90) in those who drank within guidelines, 0·69 (95 % CI 0·54, 0·88) in former drinkers and 0·50 (95 % CI 0·40, 0·63) in never drinkers; and, these associations were biased away from the null after adjustment for drinking volume. Abstinence was associated with increased risk of obesity in women. These data suggest that the association between drinking frequency and obesity is bell-shaped, with obesity risk not significantly different in those who drink most often and never drinkers. Drinking volume has a positive confounding effect on the association between drinking frequency and obesity, which may help explain the conflicting findings of other studies.
From obduction to continental collision: new data from Central Greece
Authors: NIRTA GIUSEPPE , MORATTI GIOVANNA , PICCARDI LUIGI , MONTANARI DOMENICO , CARRAS NICOLAOS , CATANZARITI RITA , CHIARI MARCO , MARCUCCI MARTA
Published: January 2018

The aim of this paper is to contribute to deciphering the evolutionary history of the Hellenides by the study of a large sector of the chain located between the front of the ophiolitic units and the external zones classically attributed to the continental margin of Adria. In particular, the tectonic units located in Boeotia – a key area located in Central Greece at the boundary between the Internal and External Hellenides – were studied from structural, stratigraphic and biostratigraphic points of view. Addressing the main debated aspects concerning the origin of the ophiolite nappe(s), the tectonic evolution of the Hellenic orogen was revised with a particular emphasis on the period between obduction and continental collision. New findings were compared with consolidated data concerning the main metamorphic events recorded in the more Internal Hellenides, geochemistry and age of the ophiolites and main stratigraphic constraints obtained in other sectors of the belt. Finally, a new reconstruction of the tectonic evolution of this area was introduced and, in the context of the dispute concerning the origin of the ‘ophiolitic belts’ as a possible record of multiple oceanic basins, we put forward for consideration a ‘single ocean’ tectonic model spanning from Triassic up to Tertiary times, and valid for the whole Hellenic–Albanian sector.
Negative energy standing wave instability in the presence of flow
Authors: Ruderman Michael S.
Published: January 2018

We study standing waves on the surface of a tangential discontinuity in an incompressible plasma. The plasma is moving with constant velocity at one side of the discontinuity, while it is at rest at the other side. The moving plasma is ideal and the plasma at rest is viscous. We only consider the long wavelength limit where the viscous Reynolds number is large. A standing wave is a superposition of a forward and a backward wave. When the flow speed is between the critical speed and the Kelvin–Helmholtz threshold the backward wave is a negative energy wave, while the forward wave is always a positive energy wave. We show that viscosity causes the standing wave to grow. Its increment is equal to the difference between the negative energy wave increment and the positive energy wave decrement.
A botanical mystery solved by phylogenetic analysis of botanical garden collections: the rediscovery of the presumed-extinct Dracaena umbraculifera
Authors: Edwards Christine E. , Bassüner Burgund , Birkinshaw Chris , Camara Christian , Lehavana Adolphe , Lowry Porter P. , Miller James S. , Wyatt Andrew , Jackson Peter Wyse
Published: January 2018

Extinction is the complete loss of a species, but the accuracy of that status depends on the overall information about the species. Dracaena umbraculifera was described in 1797 from a cultivated plant attributed to Mauritius, but repeated surveys failed to relocate it and it was categorized as Extinct on the IUCN Red List. However, several individuals labelled as D. umbraculifera grow in botanical gardens, suggesting that the species’ IUCN status may be inaccurate. The goal of this study was to understand (1) where D. umbraculifera originated, (2) which species are its close relatives, (3) whether it is extinct, and (4) the identity of the botanical garden accessions and whether they have conservation value. We sequenced a cpDNA region of Dracaena from Mauritius, botanical garden accessions labelled as D. umbraculifera, and individuals confirmed to be D. umbraculifera based on morphology, one of which is a living plant in a private garden. We included GenBank accessions of Dracaena from Madagascar and other locations and reconstructed the phylogeny using Bayesian and parsimony approaches. Phylogenies indicated that D. umbraculifera is more closely related to Dracaena reflexa from Madagascar than to Mauritian Dracaena. As anecdotal information indicated that the living D. umbraculifera originated from Madagascar, we conducted field expeditions there and located five wild populations; the species’ IUCN status should therefore be Critically Endangered because < 50 wild individuals remain. Although the identity of many botanical garden samples remains unresolved, this study highlights the importance of living collections for facilitating new discoveries and the importance of documenting and conserving the flora of Madagascar.
Competition of Prickly Sida with Cotton
Authors: Buchanan G.A. , Crowley R.H. , McLaughlin R.D.
Published: January 2018

Seed cotton (Gossypium hirsutumL.) yields were not reduced when competing with prickly sida (Sida spinosaL.) for 7 weeks or less after cotton emergence and maintained weed-free for the remainder of the season. Cotton yields were not affected when pure prickly sida stands were controlled for 5 to 6 weeks after cotton emergence and then allowed to grow uncontrolled for the remainder of the season. In the more severe weed competition treatments, cotton plant height and main stem diameter were reduced; however, yield of seed cotton was the most sensitive indicator of prickly sida competition. Maturity of cotton, as measured by percent of total yield obtained at first picking, indicated a delay in maturity in 1 of 3 yr in treatments where competing prickly sida was present for 8 weeks or more. In density studies, where prickly sida emerged with cotton and was allowed to compete for the full growing season, 45 prickly sida plants/15 m of row caused reductions in yield of seed cotton in two of five experiments. In another series of three experiments as few as 32 prickly sida plants/15 m of row significantly reduced seed cotton yields in two of the three experiments. Trash content of machine-harvested cotton was increased at densities of 64 and 128 prickly sida plants/15 m of row in one experiment. Staple length and grade of cotton were not affected by any weed density studied. Micronaire measurements of cotton were reduced at prickly sida densities of 64 and 128 weeds/15 m of row during 1972.
Winter Annual Weed Control in Dormant Bermudagrass Turf
Authors: Johnson B.J.
Published: January 2018

Control of annual broadleaf winter weeds in dormant bermudagrass [Cynodon dactylon(L.) Pers. ‘Common’] by a variety of herbicides was examined. Nearly all treatments allowed good to excellent control of spur weed (Soliva sessilisP. and K.). Metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazine-5(4H)one] was the only tested herbicide that controlled all weed species consistently with a single treatment. Bentazon [3-isopropyl-1H-2,1,3-benzothiadiazin-(4) 3H-one 2,2-dioxide] applied alone as single or repeated treatments controlled spur weed, parsley-piert (Alchemilla microcorpaBoissier Reuter), and chickweed [Stellaria media(L.) Cyrillo], but a combination of bentazon and silvex [2-(2,4,5-trichlorophenoxy)propionic acid] were needed for acceptable control of henbit (Lamium amplexicauleL.) and corn speedwell (Veronica arvensisL.). None of the herbicide treatments affected green-up of bermudagrass the following spring.
Effects of Density and Species Proportion on Competition between Spurred Anoda (Anoda cristata) and Velvetleaf (Abutilon theophrasti)
Authors: Patterson David T.
Published: January 2018

Spurred anoda and velvetleaf were grown for 40 days in controlled-environment chambers in monocultures at densities of 2, 4, 8, and 12 plants per 20-cm-diam pot and in mixed culture with all combinations of 2, 4, 8, and 12 plants of each species per pot. The day/night temperature was 29/23 C, and the photosynthetic photon flux density (PPFD) was 1000 μE m–2s–1. Shoot dry weights and leaf areas of the two species were similar when they were grown in monoculture. However, in mixed culture spurred anoda exceeded velvetleaf in leaf area/plant and shoot weight/plant in 15 out of 16 treatments. Multiple linear regression equations relating shoot biomass/plant to the density of both species in mixed culture were calculated. Comparison of competition coefficients from these equations indicated that the competitive impact of a single spurred anoda plant was equivalent to the impact of 2.5 velvetleaf plants. In mixed culture, spurred anoda always contributed a greater proportion of the total shoot weight and total leaf area per pot than would be predicted from its proportion of the total plant population. These results indicate spurred anoda is competitively superior to velvetleaf.
Soil Temperature, Soil Moisture, and Seed Burial Depth Effects on Redstem Filaree (Erodium cicutarium) Emergence
Authors: Blackshaw Robert E.
Published: January 2018

A study was conducted under controlled environmental conditions to determine the effect of soil temperature, soil moisture, and depth of seed burial on the emergence of redstem filaree. Emergence occurred from 5 to 30 C but was optimal at 5 to 15 C. Redstem filaree emergence was optimal in moist soil with water contents of −0.03 to −0.28 MPa. Emergence progressively decreased as soil moisture was lowered below these levels, with less than 25% emergence attained at −1.53 MPa regardless of soil temperature. Almost no germination was observed in warm (30 C), dry (-1.03 to −1.53 MPa) soils. Rate of emergence was affected more by soil temperature than by moisture. A decrease in temperature from 20 to 5 C increased the time to reach 50% emergence by 6 to 8 d but a decrease in soil moisture from −0.03 to −1.53 MPa increased the time to reach 50% emergence by only 1 to 2 d. Emergence was greatest at soil depths of 1 cm or less. No emergence occurred at depths of 8 cm or below.
Effect of Soluble Sugars and Gibberellic Acid in Breaking Dormancy of Excised Wild Oat (Avena fatua) Embryos
Authors: Foley Michael E.
Published: January 2018

Dormant line M73 wild oat caryopses were utilized to develop a system for the culture of excised embryos, to evaluate whether embryo dormancy exists, and to investigate the physiological basis for breaking dormancy. Dormant embryos cultured on N6 medium solidified with 0.25% Bacto agar displayed 70% germination in 2 d compared with approximately 20% for the other gelling agents. The non-plant-based gelling agent gellum at a concentration of 0.25% was selected for further experiments on breaking dormancy after it was determined that concentrations ≥ 0.5% decreased the rate of germination. Amending N6 medium with concentrations of 0.1 to 10 μM gibberellic acid (GA) increased the rate and extent of germination. Embryos treated with 0 to 0.01 μM GA required 6 d to attain 90% germination. Germination of dormant embryos on N6 medium without GA suggested that either true embryo dormancy did not exist in M73 or some constituent of the N6 medium promoted breaking of dormancy. Subsequent experiments indicated that the 88 mM sucrose was the constituent in the N6 medium responsible for breaking dormancy. Concentrations of sucrose from 40 to 200 mM were effective in breaking dormancy. Ten μM GA increased the rate and extent of germination of embryos cultured with 88 to 200 mM sucrose. At 88 mM, fructose, maltose, glucose, and sucrose all broke embryo dormancy. Fructose was the most active soluble sugar for breaking embryo dormancy, promoting nearly 100% germination in 4 d. As with sucrose, there was an interaction between GA and the soluble sugars in breaking dormancy. Ten μM GA with 88 mM fructose provided nearly 100% germination in 1 d. Amylose, but not amylopectin or pullulan, may substitute for soluble sugars. However, with 10 μM GA amylose, amylopectin and pullulan were equally effective in breaking dormancy. Breaking dormancy of embryos on N6 medium was independent of temperatures from 12 to 24 C in the presence of GA, but in its absence the optimum was 12 C. Application of GA to dormant caryopses significantly increased and decreased the level of glucose and sucrose, respectively, in the embryo. Gibberellic acid had a similar effect on glucose and sucrose in the endosperm tissue, except the differences were not significant at all times after treatment. The change in carbohydrate metabolism, especially in embryo tissue, may be important when considered in context with the observation that soluble sugars and GA act independently in breaking dormancy in excised M73 embryos. Breaking wild oat embryo dormancy with GA may be mainly a substitution for sugar requirement.
Use of Ethylene and Nitrate to Break Seed Dormancy of Common Lambsquarters (Chenopodium album)
Authors: Saini Hargurdeep S. , Bassi Pawan K. , Spencer Mary S.
Published: January 2018

Effects of ethylene and KNO3on the germination of dormant common lambsquarters (Chenopodium albumL. # CHEAL) seed were studied under controlled environmental conditions. Ethylene, applied in the gaseous form or as an aqueous solution of ethephon (2-chloroethylphosphonic acid), was able to overcome the dormancy of over 70% of the seed. The optimum concentrations of ethylene and ethephon were 10 μL·L-1and 100 mg·L-1, respectively. The dormancy-breaking action of ethylene was dependent on the availability of nitrate. Hence, seed containing a high level of endogenous nitrate responded readily to ethylene, whereas nitrate-deficient seed required a combined application of ethylene and nitrate. Stimulation of seed germination by ethylene was observed in soil at all depths studied (up to 15 cm). The sensitivity of seed to ethylene increased upon imbibition to reach a peak on the third day, followed by a steady decline. Consequently, the greatest promotion of germination occurred when ethylene was administered during the first 3 to 4 days of imbibition. The loss of seed sensitivity was neither preempted nor overcome by an exogenous supply of KNO3, and may imply that the seed had passed into secondary dormancy. The present findings could form the basis for the use of ethylene to accomplish commercially significant promotion of germination in the field and thus improve the efficiency of the control of common lambsquarters.
Isozyme Variability and Breeding Systems in Populations of Yellow Nutsedge (Cyperus esculentus)
Authors: Horak Michael J. , Holt Jodie S.
Published: January 2018

The importance of seeds in the reproduction and maintenance of yellow nutsedge (Cyperus esculentusL. # CYPES) populations was evaluated. Isozyme analysis using starch gel electrophoresis was performed on 20 individuals of each of 10 widely separate populations in California. Genetic variation among individuals served as an indicator of the relative importance of asexual and sexual reproduction in each population. Eight enzyme systems were assayed from which 12 loci were resolvable, with four of those loci exhibiting variability. A maximum of four isozyme genotypes appeared in any population; only nine of 81 total potential genotypes were identified. Five populations were isozymically uniform, apparently composed of a single genotype. The remaining five populations were genotypically variable; these frequently deviated strongly from the genotype frequencies expected of a sexually reproducing population. These results indicate that sexually produced seeds are unimportant in the maintenance of yellow nutsedge populations in agricultural environments. Although viable seed may be produced, tubers appear to be the primary mode of reproduction in this species.
Antimicrobial Activity of Velvetleaf (Abutilon theophrasti) Seeds
Authors: Kremer Robert J.
Published: January 2018

Velvetleaf (Abutilon theophrastiMedik. # ABUTH) seeds were bioassayed on 241 microbial isolates to assess their antimicrobial activity. Seeds placed on agar plates inoculated with test microorganisms released a diffusible substance(s) that inhibited the growth of 117 of 202 (58%) bacteria and all of the fungi tested. Antimicrobial activity of the seeds appeared to be nonselective as the extent of inhibition was not related to type of microorganism nor their origin. Hard, water-impermeable seeds had greater inhibitory activity than imbibed (soft) seeds. The intensity of inhibition was affected by prior leaching of seeds with various solvents and by the stage of seed development. Chemical analysis of diffusion zones from agar plates and seed leachates revealed the presence of phenolic compounds. The presence of antimicrobial substances in velvetleaf seeds may contribute to the persistence of viable seeds in soil by inhibiting potential seed-deteriorating microorganisms.
Pugin’s Churches
Authors: Hill Rosemary
Published: January 2018

This article is intended as a companion to ‘Pugin’s Small Houses’ published here three years ago. It follows the same method, tracing the development of Pugin’s ideas about a single building type over the course of his career by way of the most significant examples. It would be impractical to discuss every church, and in assessing significance I have considered how relevant a particular building may be to the overall direction of Pugin’s thinking. Some major buildings, such as St Barnabas, Nottingham, are touched on only briefly because little or nothing followed directly from them. By the same token a relatively minor work, such as St Wilfred’s Hulme, may in this context be revealing. At times it will be necessary to discuss Pugin’s work in other building types.
Seeing the collective: family arrangements for care at home for older people with dementia
Authors: CECI CHRISTINE , SYMONDS BROWN HOLLY , PURKIS MARY ELLEN
Published: January 2018

With the predicted growth in the number of people with dementia living at home across the globe, the need for home-based care is expected to increase. As such, it will be primarily family carers who will provide this crucial support to family members. Designing appropriate support for family carers is thus essential to minimise risks to their health, to prevent premature institutionalisation or poor care for persons with dementia, as well as to sustain the effective functioning of health and social care systems. To date, the high volume of research related to care at home and acknowledged low impact of interventions suggests that a re-examination of the nature of care at home, and how we come to know about it, is necessary if we are to advance strategies that will contribute to better outcomes for families. This paper describes findings from an ethnographic study that was designed to support an analysis of the complexity and materiality of family care arrangements – that is, the significance of the actual physical, technological and institutional elements shaping care-giving situations. In this paper, we describe the arrangements made by one family to show the necessary collectivity of these arrangements, and the consequences of the formal care system's failure to respond to these.
Childlessness and upward intergenerational support: cross-national evidence from 11 European countries
Authors: PESANDO LUCA MARIA
Published: January 2018

Childless individuals are often depicted as ‘selfish’ as they opt out of raising children in favour of investing resources in themselves. Yet no research has investigated whether this claim holds in domains of social life such as intergenerational family support. Using data from the Generations and Gender Survey for 11 European countries, this article examines differences between childless and non-childless individuals in the provision of financial, practical and emotional transfers to their elderly parents. Results support the idea that the childless are more prone to provide upward support than individuals with children. Specifically, estimates from multivariate logistic regression and propensity score specifications suggest that,ceteris paribus, childless adults are about 20–40 per cent more likely to provide support to their parents, with the association driven by transfers to elderly mothers. These findings enrich the literature on childlessness and ageing, and support the view that researchers and policy makers should take into more consideration not only what childless people receive or need in old age, but also what they provide as middle-aged adults.
Conditioning calves to accept high Na feeds
Authors: Phillips C.J.C. , Youssef M.
Published: January 2018

In saline areas livestock are often offered food and water with high sodium contents and there is evidence for major effects of the sodium content of feeds on their palatability, ingestive behaviour and the performance of ruminants (Youssef et al 1993). The aim in this experiment was to examine whether calves could be conditioned to accept high sodium feeds by early experience.

Sixteen dairy Friesian heifer calves, aged 7 days, were allocated to receive their ad libitum concentrate feed with or without 27g added Na/calf/day, up to weaning at 6 weeks. The daily concentrate and water intakes were recorded for each calf until weaning time. The behaviour of calves was also observed for 12 hours per week at 8 min-intervals throughout the weaning period. At 6 months of age, calves were offered silage with added sodium, to give 0.1, 0.3, 0.5, 0.7, 0.8, 1.1, 1.3 and 1.5% sodium content in the DM. The daily silage intake for each calf was recorded for 2 weeks, beside observing the ingestive behaviour of calves for 24 hours at 3 min - intervals.
Metabolic effects of fibrous ingredients in pig diets
Authors: Brouns F. , Edwards S.A. , English P.R.
Published: January 2018

Previous experiments indicated that several fibrous raw materials in dry sow diets failed to prevent excessive nutrient intake. Only a diet high in unmolassed sugar-beet pulp (SBP) limited voluntary intake to acceptable levels. SBP consists of mainly soluble fibre. It is known that some types of fibre can affect blood metabolites and hormone profiles, which might affect intake regulation. The effects on blood metabolites and insulin of a diet containing soluble or insoluble fibre were compared to a diet containing readily available carbohydrates.