Ontogeny and structure of the acervulate partial inflorescence in Hyophorbe lagenicaulis (Arecaceae; Arecoideae)

Background and Aims The palm tribe Chamaedoreeae displays flowers arranged in a complex partial inflorescence called an acervulus. This type of partial inflorescence has so far not been reported elsewhere in the largest palm subfamily Arecoideae, which is traditionally characterized by flowers predominantly arranged in triads of one central female and two lateral male flowers. The ontogenetic basis of the acervulus is as yet unknown and its structural diversity throughout the genera of the Chamaedoreeae poorly recorded. This study aims to provide critical information on these aspects. Methods Developmental series and mature inflorescences were sampled from plants cultivated in international botanical gardens and wild populations. The main techniques employed included scanning electronic microscopy and serial anatomical sectioning of resin-embedded fragments of rachillae. Key Results Inflorescence ontogeny in Hyophorbe lagenicaulis demonstrates that the acervulus and the inflorescence rachilla form a condensed and cymose branching system resembling a coenosome. Syndesmy results from a combined process of rapid development and adnation, without or with reduced axis elongation. Acervulus diversity in the ten taxa of the Chamaedoreeae studied is displayed at the level of their positioning within the inflorescence, their arrangement, the number of floral buds and their sexual expression. Conclusions The results show that a more general definition of the type of partial inflorescence observed within the large subfamily Arecoideae would correspond to a cyme rather than to a floral triad. In spite of their common cymose architecture, the floral triad and the acervulus present differences with respect to the number and arrangement of floral buds, the superficial pattern of development and sexual expressio

Torsional stick-slip vibrations and multistability in drill-strings

This is the final version. Available on open access from Elsevier via the DOI in this recordData accessibility: The datasets generated and analysed during the current study are available from the corresponding author on reasonable request.The generalized lumped-parameter model of the drill-string system is studied in this paper to provide a fundamental understanding of the torsional stick-slip vibrations in downhole drilling. Our investigation focuses on analysing the cause of three coexisting states: bit sticking, stick-slip vibration, and constant rotation. A critical region of multistability is identified based on the lumped-parameter model, and the conditions for switching between these multiple stable states are discussed. Special attention is given to the bifurcation structure of the considered drill-string model, which is obtained via path-following methods for nonsmooth dynamical systems. The bifurcation scenario is compared to the case when a longer drill-string is considered, which amounts to drilling deeper. It is found that the main features of the bifurcation picture persist under variation of the drill-string length, with certain numerical differences regarding for instance the window of multistability.Engineering and Physical Sciences Research Council (EPSRC)National Natural Science Foundation of ChinaChina Scholarship Counci

A possible origin of superconducting currents in cosmic strings

The scattering and capture of right-handed neutrinos by an Abelian cosmic string in the SO(10) grand unification model are considered. The scattering cross-section of neutrinos per unit length due to the interaction with the gauge and Higgs fields of the string is much larger in its scaling regime than in the friction one because of the larger infrared cutoff of the former.The probability of capture in a zero mode of the string accompanied by the emission of a gauge or Higgs boson shows a resonant peak for neutrino momentum of the order of its mass. Considering the decrease of number of strings per unit comoving volume in the scaling epoch the cosmological consequences of the superconducting strings formed in this regime will be much smaller than those which could be produced already in the friction one.Comment: 14 pages Latex, 4 figues/ep

Evolving a lipase for hydrolysis of natural triglycerides along with enhanced tolerance towards a protease and surfactants

In the accompanying paper, we described evolving a lipase to the point where variants were soluble, stable and capable of degrading C8 TAG and C8 esters. These variants were tested for their ability to survive in an environment that might be encountered in a washing machine. Unfortunately, they were inactivated both by treatment with a protease used in laundry detergents and by very low concentrations of sodium dodecyl sulfate (SDS). In addition, all the variants had very low levels of activity with triglycerides with long aliphatic chains and with naturally occurring oils, like olive oil. Directed evolution was used to select variants with enhanced properties. In the first 10 rounds of evolution, the primary screen was selected for variants capable of hydrolyzing olive oil whereas the secondary screen was selected for enhanced tolerance towards a protease and SDS. In the final six rounds of evolution, the primary and secondary screens identified variants that retained activity after treatment with SDS. Sixteen cycles of evolution gave variants with greatly enhanced lipolytic activity on substrates that had both long (C16 and C18) as well as short (C3 and C8) chains. We found variants that were stable for more than 3 hours in protease concentrations that rapidly degrade the wild-type enzyme. Enhanced tolerance towards SDS was found in variants that could break down naturally occurring lipid and resist protease attack. The amino acid changes that gave enhanced properties were concentrated in the cap domain responsible for substrate binding

Producción de forraje verde hidropónico de cebada (Hordeum vulgare) usando efluente de piscigranja de truchas

The objective was to determine the effect of trout farm effluent on the production of green hydroponic forage of barley (GHF). The activities were: oxidation of ammonia (N-NH4+) in the trout farm effluent to nitrate of nitrogen (N-NO3-) in a biofilter (nitrification), and the use of this effluent in the production of GHF. Design was completely randomized with three treatments: 100% of water from water supply channel (T0), 50% of water from biofilter effluent, plus 50% of water from water supply channel (T1), and 100% of water from biofilter effluent (T2); with 10 replications. Variables assessed were: development time of biofilter; NNO3- content in fully developed biofilter; percentage of protein and plant height on 4th, 8th, 12th, and 16th day production; and biomass production of GHF on 16th day. By the end of the 90th day, the biofilter installed to generate N-NO3- was developed at a medium pH of 8.23 and at a medium temperature of 14.9°C. N-NO3- content (mg/L) in biofilter effluent was 2.2 while trout farm effluent was 1.2. No significant difference was found in protein percentage of GHF (P<0.05). However, there was a highly significant effect (P<0.01) on plant height the 4th, 8th, 12th, and 16th days, and biomass production on the 16th day. For both variables, treatment T2 was placed in the A range, treatment T1 in B range and treatment T0 in C range.El objetivo fue determinar el efecto del efluente de pozas de trucha sobre la producción de forraje verde hidropónico de cebada (FVH). Las actividades fueron: La oxidación del amoniaco (N-NH4+) – en el efluente de las pozas de trucha – hasta nitrato (N-NO3-) en un biofiltro (nitrificación) y el uso del efluente en la producción de FVH. Se utilizó el diseño completamente al azar con tres tratamientos: 100% de agua del canal de abastecimiento (T0), 50% de efluente del biofiltro más 50% de agua del canal de abastecimiento (T1) y 100% de efluente del biofiltro (T2); con 10 repeticiones. Las variables evaluadas fueron: tiempo de desarrollo del biofiltro, contenido de N-NO3- en el biofiltro completamente desarrollado, porcentaje de proteína y altura de planta los días 4, 8, 12 y 16 de producción; y producción de biomasa del FVH el día 16. El biofiltro instalado para la generación de N-NO3- se desarrolló a los 90 días, a un pH medio de 8.23 y una temperatura media de 14.9 °C. El contenido de NNO3-(mg/L) en el efluente del biofiltro fue de 2.2 y en el de las pozas de trucha, 1.2. No se encontraron diferencias significativas (P<0.05) en porcentaje de proteína del FVH, pero se observó un efecto altamente significativo (P<0.01) en la altura de planta los días 4, 8, 12 y 16, asimismo en la producción de biomasa del día 16. Para ambas variables el tratamiento T2 se ubicó en el rango A, el tratamiento T1 en el rango B y el tratamiento T0 en el rango C

Meeting irrigation demands in a water-challenged environment

Presented at Meeting irrigation demands in a water-challenged environment: SCADA and technology: tools to improve production: a USCID water management conference held on September 28 - October 1, 2010 in Fort Collins, Colorado.Includes bibliographical references.Accurate estimates of spatially distributed evapotranspiration (ET) using remote sensing inputs could help improve crop water management, the assessment of regional drought conditions, irrigation efficiency, ground water depletion, and the verification of the use of water rights over large irrigated areas. In this study, ET was mapped using surface reflectance and radiometric temperature images from the Landsat 5 satellite in a surface energy budget algorithm driven by a surface aerodynamic temperature (SAT_ET) model. The SAT_ET model was developed using surface temperature, horizontal wind speed, air temperature and crop biophysical characteristic measured over an irrigated alfalfa field in Southeastern Colorado. Estimates of the remote sensing-based ET for a 4.0 hectare alfalfa field and a 3.5 hectare oats field, during the 2009 cropping season, were evaluated using two monolithic weighing lysimeters located at the Colorado State University Arkansas Valley Research Center (AVRC) in Rocky Ford, Colorado. Although the overall model performance was encouraging, results indicated that the SAT_ET model performed well under dry atmospheric and soil conditions and less accurately under high air relative humidity and soil water content conditions. These findings are evidence that SAT_ET needs to be further developed to perform better under a range of environmental and atmospheric conditions

A preliminary study of genetic factors that influence susceptibility to bovine tuberculosis in the British cattle herd

Associations between specific host genes and susceptibility to Mycobacterial infections such as tuberculosis have been reported in several species. Bovine tuberculosis (bTB) impacts greatly the UK cattle industry, yet genetic predispositions have yet to be identified. We therefore used a candidate gene approach to study 384 cattle of which 160 had reacted positively to an antigenic skin test (‘reactors’). Our approach was unusual in that it used microsatellite markers, embraced high breed diversity and focused particularly on detecting genes showing heterozygote advantage, a mode of action often overlooked in SNP-based studies. A panel of neutral markers was used to control for population substructure and using a general linear model-based approach we were also able to control for age. We found that substructure was surprisingly weak and identified two genomic regions that were strongly associated with reactor status, identified by markers INRA111 and BMS2753. In general the strength of association detected tended to vary depending on whether age was included in the model. At INRA111 a single genotype appears strongly protective with an overall odds ratio of 2.2, the effect being consistent across nine diverse breeds. Our results suggest that breeding strategies could be devised that would appreciably increase genetic resistance of cattle to bTB (strictly, reduce the frequency of incidence of reactors) with implications for the current debate concerning badger-culling

Stick-slip suppression and speed tuning for a drill-string system via proportional-derivative control

This is the final version. Available from Elsevier via the DOI in this record. This paper studies the problems of stick-slip mitigation and speed tuning for a lumped-parameter drill-string system by using a proportional-derivative feedback controller via path-following analysis. In this study, we consider two main control parameters, the weight-on-bit and the desired drill-bit speed, which in general differs from the real angular speed. In particular, we determine the combinations of these two parameters for which the proposed control scheme is applicable, which is affected by the non-smooth nature of the system induced by bit-rock interaction. Our analysis using path-following techniques for non-smooth systems reveals the inherent coexistence of stick-slip vibration and constant rotation, and identifies a critical point where the drill-bit speed coincides with the desired angular speed. Furthermore, our analysis proposes a strategy that allows controlling the drill-bit speed to suppress stick-slip, by tuning the controller in a suitable manner.Engineering and Physical Sciences Research Council (EPSRC