Estimation and reduction of the uncertainties in chemical models: Application to hot core chemistry

It is not common to consider the role of uncertainties in the rate coefficients used in interstellar gas-phase chemical models. In this paper, we report a new method to determine both the uncertainties in calculated molecular abundances and their sensitivities to underlying uncertainties in the kinetic data utilized. The method is used in hot core models to determine if previous analyses of the age and the applicable cosmic-ray ionization rate are valid. We conclude that for young hot cores ($\le 10^4$ yr), the modeling uncertainties related to rate coefficients are reasonable so that comparisons with observations make sense. On the contrary, the modeling of older hot cores is characterized by strong uncertainties for some of the important species. In both cases, it is crucial to take into account these uncertainties to draw conclusions from the comparison of observations with chemical models.Comment: Accepted for publication in A&

FORCE-VELOCITY RELATIONSHIP OF LEG MUSCLES ASSESSED BY MOTORIZED TREADMILL TESTS

We aimed to explore the properties of the F-V relationship of leg muscles exerting the maximum pulling F within a wide range of V set on a standard motorized treadmill. Subjects exerted maximum horizontally pulling F while walking on a treadmill set to 8 different V (1.4 - 3.3 m/s). The obtained F-V relationships proved to be linear and strong (all R \u3e 0.84), while their parameters depicting the leg muscle capacities for producing maximum F, V, and power (i.e., the maximum product of F and V) were highly reliable (0.84 \u3c ICC \u3c 0.97; 6.4 \u3c CV% \u3c 19.3). Moreover, when obtained from only the lowest and highest V the F-V relationships revealed virtually identical outcomes. We conclude that the evaluated procedure could be developed into an ecologically valid and reliable protocol for routine testing of the F, V, and P-producing capacities of leg muscles

pET expression vector customized for efficient seamless cloning

Here we present a modification of the widely used pET29 expression vector for use in rapid and straightforward parallel cloning via a gene replacement and Golden Gate strategy. The modification can be applied to other expression vectors for Gram-negative bacteria. We have used the modified vectors to clone large numbers of bacterial natural enzyme variants from genomic and metagenomic sources for applications in biocatalysis

Decoupling the Effects of Atmospheric Humidity and Soil Moisture on Cereal Physiology

Climate change is driving perturbations to global humidity levels with rises and falls already observed across many of the crop growing regions whilst drought continues to threaten agricultural productivity. Soil moisture content determines how much water can be supplied to a plant and atmospheric humidity influences vapour pressure deficit (VPD) thus driving transpirational demand. The influences of both this supply and demand on plant physiology are often overlooked, with drought study research seldom focused on the possible influences of humidity. This thesis aims to address this problem by decoupling the effects of humidity and soil moisture on maize (Zea mays) and wheat (Triticum aestivum cv. Paragon) through controlled growth under four treatments; high humidity high soil moisture, high humidity low soil moisture, low humidity high soil moisture, low humidity low soil moisture. This thesis found distinct differences in response between young maize and wheat crops with maize appearing more sensitive to humidity and wheat more to soil moisture. There was also variation between species in which areas of physiology were influenced most by the treatment conditions, as maize showed more responses related to biomass production and root architecture, whereas wheat gas exchange and stomatal morphology were more heavily impacted. This thesis highlights the importance of studying the effects of humidity and soil moisture concurrently as both maize and wheat were affected by individual treatments as well as significant interactions between the two. There is also evidence that high humidity could be mitigating some effects of low soil moisture conditions in the early growth of both species, which could have big impacts on future irrigation practices, commercial glasshouses, and predictive hydraulic and climatic models

Decoupling the Effects of Atmospheric Humidity and Soil Moisture on Cereal Physiology

Climate change is driving perturbations to global humidity levels with rises and falls already observed across many of the crop growing regions whilst drought continues to threaten agricultural productivity. Soil moisture content determines how much water can be supplied to a plant and atmospheric humidity influences vapour pressure deficit (VPD) thus driving transpirational demand. The influences of both this supply and demand on plant physiology are often overlooked, with drought study research seldom focused on the possible influences of humidity. This thesis aims to address this problem by decoupling the effects of humidity and soil moisture on maize (Zea mays) and wheat (Triticum aestivum cv. Paragon) through controlled growth under four treatments; high humidity high soil moisture, high humidity low soil moisture, low humidity high soil moisture, low humidity low soil moisture. This thesis found distinct differences in response between young maize and wheat crops with maize appearing more sensitive to humidity and wheat more to soil moisture. There was also variation between species in which areas of physiology were influenced most by the treatment conditions, as maize showed more responses related to biomass production and root architecture, whereas wheat gas exchange and stomatal morphology were more heavily impacted. This thesis highlights the importance of studying the effects of humidity and soil moisture concurrently as both maize and wheat were affected by individual treatments as well as significant interactions between the two. There is also evidence that high humidity could be mitigating some effects of low soil moisture conditions in the early growth of both species, which could have big impacts on future irrigation practices, commercial glasshouses, and predictive hydraulic and climatic models

The impact of atmospheric circulation on the chemistry of the hot Jupiter HD 209458b

This is the author accepted manuscript. The final version is available from EDP Sciences via the DOI in this record.We investigate the effects of atmospheric circulation on the chemistry of the hot Jupiter HD 209458b. We use a simplified dynamical model and a robust chemical network, as opposed to previous studies which have used a three dimensional circulation model coupled to a simple chemical kinetics scheme. The temperature structure and distribution of the main atmospheric constituents are calculated in the limit of an atmosphere that rotates as a solid body with an equatorial rotation rate of 1 km/s. Such motion mimics a uniform zonal wind which resembles the equatorial superrotation structure found by three dimensional circulation models. The uneven heating of this tidally locked planet causes, even in the presence of such a strong zonal wind, large temperature contrasts between the dayside and nightside, of up to 800 K. This would result in important longitudinal variations of some molecular abundances if the atmosphere were at chemical equilibrium. The zonal wind, however, acts as a powerful disequilibrium process. We identify the existence of a pressure level of transition between two regimes, which may be located between 100 and 0.1 mbar depending on the molecule. Below this transition layer, chemical equilibrium holds, while above it, the zonal wind tends to homogenize the chemical composition of the atmosphere, bringing molecular abundances in the limb and nightside regions close to chemical equilibrium values characteristic of the dayside, i.e. producing an horizontal quenching effect in the abundances. Reasoning based on timescales arguments indicates that horizontal and vertical mixing are likely to compete in HD 209458b's atmosphere, producing a complex distribution where molecular abundances are quenched horizontally to dayside values and vertically to chemical equilibrium values characteristic of deep layers.M.A., O.V., F.S., and E.H. acknowledge support from the European Research Council (ERC Grant 209622: E3ARTHs). Computer time for this study was provided by the computing facilities MCIA (Mésocentre de Calcul Intensif Aquitain) of the Université de Bordeaux and of the Université de Pau et des Pays de l’Adour. We thank the anonymous referee for a constructive report that helped to improve this manuscript

C₂N₂ vertical profile in Titan's stratosphere

In this paper, we present the first measurements of the vertical distribution of cyanogen (${{\rm{C}}}_{2}{{\rm{N}}}_{2}$) in Titan's lower atmosphere at different latitudes and seasons, using Cassini's Composite Infrared Spectrometer far-infrared data. We also study the vertical distribution of three other minor species detected in our data: methylacetylene (${{\rm{C}}}_{3}{{\rm{H}}}_{4}$), diacetylene (${{\rm{C}}}_{4}{{\rm{H}}}_{2}$), and ${{\rm{H}}}_{2}{\rm{O}}$, in order to compare them to ${{\rm{C}}}_{2}{{\rm{N}}}_{2}$, but also to get an overview of their seasonal and meridional variations in Titan's lower stratosphere from 85 km to 225 km. We measured an average volume mixing ratio of ${{\rm{C}}}_{2}{{\rm{N}}}_{2}$ of $6.2\pm 0.8\times {10}^{-11}$ at 125 km at the equator, but poles exhibit a strong enrichment in ${{\rm{C}}}_{2}{{\rm{N}}}_{2}$ (up to a factor 100 compared to the equator), greater than what was measured for ${{\rm{C}}}_{3}{{\rm{H}}}_{4}$ or ${{\rm{C}}}_{4}{{\rm{H}}}_{2}$. Measuring ${{\rm{C}}}_{2}{{\rm{N}}}_{2}$ profiles provides constraints on the processes controlling its distribution, such as bombardment by Galactic Cosmic Rays which seem to have a smaller influence on ${{\rm{C}}}_{2}{{\rm{N}}}_{2}$ than predicted by photochemical models

First observation of CO at 345 GHz in the atmosphere of Saturn with the JCMT. New constaints on its origin

International audienceWe have performed the first observation of the CO(3-2) spectral line in the atmosphere of Saturn with the James Clerk Maxwell Telescope. We have used a transport model of the atmosphere of Saturn to constrain the origin of the observed CO. The CO line is best-fit when the CO is located at pressures less than (15± 2) mbar with a mixing ratio of (2.5±0.6)×10-8 implying an external origin. By modelling the transport in Saturn's atmosphere, we find that a cometary impact origin with an impact 200-350 years ago is more likely than continuous deposition by interplanetary dust particles (IDP) or local sources (rings/satellites). This result would confirm that comet impacts are relatively frequent and efficient providers of CO to the atmospheres of the outer planets. However, a diffuse and/or local source cannot be rejected, because we did not account for photochemistry of oxygen compounds. Finally, we have derived an upper limit of 1×10-9 on the tropospheric CO mixing ratio

Enzymatic synthesis of chiral amino-alcohols by coupling transketolase and transaminase-catalyzed reactions in a cascading continuous-flow microreactor system

Rapid biocatalytic process development and intensification continues to be challenging with currently available methods. Chiral amino-alcohols are of particular interest as they represent key industrial synthons for the production of complex molecules and optically pure pharmaceuticals. (2S,3R)-2-amino-1,3,4-butanetriol (ABT), a building block for the synthesis of protease inhibitors and detoxifying agents, can be synthesized from simple, non-chiral starting materials, by coupling a transketolase- and a transaminase-catalyzed reaction. However, until today, full conversion has not been shown and, typically, long reaction times are reported, making process modifications and improvement challenging. In this contribution, we present a novel microreactor-based approach based on free enzymes, and we report for the first time full conversion of ABT in a coupled enzyme cascade for both batch and continuous-flow systems. Using the compartmentalization of the reactions afforded by the microreactor cascade, we overcame inhibitory effects, increased the activity per unit volume, and optimized individual reaction conditions. The transketolase-catalyzed reaction was completed in under 10 min with a volumetric activity of 3.25 U ml-1 . Following optimization of the transaminase-catalyzed reaction, a volumetric activity of 10.8 U ml-1 was attained which led to full conversion of the coupled reaction in 2 hr. The presented approach illustrates how continuous-flow microreactors can be applied for the design and optimization of biocatalytic processes

Knowledge-Based Bioeconomy: The Use of Intellectual Capital in Food Industry of Serbia

The main objective of this exploratory study was to identify and analyse the indicators of intellectual capital in food industry of Serbia. The study investigated managers’ perceptions of their usefulness, practical application, and factors that influence them. The respondents were surveyed by means of a questionnaire. They were mainly top managers from 18 food organizations, committed to the bioeconomy paradigm. The survey items were divided into three subcategories, namely human, structural, and relational capital. The data were analysed by the SPSS 21 statistical software. The results show that all indicators were perceived as very important, relational capital indicators being the most useful of all. Of all individual items, employee motivation, market share, and employee satisfaction were perceived as the most important. This study provides a perspective on managing intellectual capital in bioeconom