1,497 research outputs found
Development of Bacillus thuringiensis CryIC resistance by Spodoptera exigua (Huebner) (Lepidoptera : Noctuidae)
Selection of resistance in Spodoptera exigua (Hubner) to an HD-1 spore-crystal mixture, CryIC (HD-133) inclusion bodies, and trypsinized toxin from Bacillus thuringiensis' subsp, aizawai and B. thuringiensis subsp. entomocidus was attempted by using laboratory bioassays. No resistance to the HD-1 spore-crystal mixture could be achieved after 20 generations of selection. Significant levels of resistance (11-fold) to CryIC inclusion bodies expressed in Escherichia coli were observed after seven generations, Subsequent selection of the CryIC-resistant population with trypsinized CryIC toxin resulted, after 21 generations of CryIC selection, in a population of S. exigua that exhibited only 8% mortality at the highest toxin concentration tested (320 mu g/g), whereas the 50% lethal concentration was 4.30 mu g/g for the susceptible colony. Insects resistant to CryIC toxin from HD-133 also were resistant to trypsinized CryIA(b), CryIC from B. thuringiensis subsp. entomocidus, CryIE-CryIC fusion protein (G27), CryIH, and CryIIA. In vitro binding experiments with brush border membrane vesicles showed a twofold decrease in maximum CryIC binding, a fivefold difference in K-d, and no difference in the concentration of binding sites for the CryIC-resistant insects compared with those for the susceptible insects, Resistance to CryIC was significantly reduced by the addition of HD-1 spores, Resistance to the CryIC toxin was still observed 12 generations after CryIC selection was removed. These results suggest that, in S. exigua, resistance to a single protein is more likely to occur than resistance to spore crystal mixtures and that once resistance occurs, insects will be resistant to many other Cry proteins, These results have important implications for devising S. exigua resistance management strategies in the field
Preserving Liveness Guarantees from Synchronous Communication to Asynchronous Unstructured Low-Level Languages
In the implementation of abstract synchronous communication in asynchronous unstructured low-level languages, e.g. using shared variables, the preservation of safety and especially liveness properties is a hitherto open problem due to inherently different abstraction levels. Our approach to overcome this problem is threefold: First, we present our notion of handshake refinement with which we formally prove the correctness of the implementation relation of a handshake protocol. Second, we verify the soundness of our handshake refinement, i.e., all safety and liveness properties are preserved to the lower level. Third, we apply our handshake refinement to show the correctness of all implementations that realize the abstract synchronous communication with the handshake protocol. To this end, we employ an exemplary language with asynchronous shared variable communication. Our approach is scalable and closes the verification gap between different abstraction levels of communication
Quantitative determination of modal content and morphological properties of coal sulphides by digital image analysis as a tool to check their flotation behaviour
An efficient depression of coal sulphides in the flotation process means a healthier environment and may be essential for the sustainability of a coal operation. Nitric and ferric oxidative pre-treatment of coal pyrite have been tested to improve pyrite depression, and the results are compared with those from the process of raw, not pre-treated coal. The removal indexes point to nitric pre-treatment as the best, but depression is still low. The microscopic study of feed and products, coupled to Digital Image Analysis (DIA) in all the cases, provide important clues to understand the behaviour of pyrite, which can be related to quantitative parameters, such as the exposition ratio (ER), and to qualified interpretation of the textures. Pyrite shows in the first float an unexpected hydrophobic behaviour, which is due to its occurrence as framboids, or porous particles which may be intergrown with organic matter and behave as coal. In general, the flotation results can be predicted from the DIA-data, e.g. depression of liberated pyrite into the tailings, increased by oxidative pre-treatments by 300% (ferric) or by > 400% (nitric); or concentration of middlings with lower pyrite ER in the floats. DIA is an efficient tool to obtain some important quantitative informations which otherwise would be inaccessible (e.g. the morphological data on > 1,000,000 pyrite particles for this study), and its use should be enhanced to check ore processing
Assessing the influence of the carbon source on the abatement of industrial N2O emissions coupled with the synthesis of added-value bioproducts
Producción CientíficaThe continuous abatement of a synthetic N2O emission from a nitric acid plant coupled with the simultaneously production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) copolymer and the coenzyme Q10 (CoQ10) in a bubble column reactor (BCR) was tested using methanol, glycerol and a mixture of sodium acetate-acetic acid (Ac-HAc) as a carbon and electron donor source. The BCRs were inoculated with Paracoccus denitrificans and supplied with the carbon/electron donor at a loading rate of 139 g C m− 3 d− 1. High N2O removal efficiencies (81–91%) were achieved, with glycerol supporting the highest abatement. The PHBV cell content ranged from 25 to 53%, with highest accumulation in the culture obtained with methanol and Ac-HAc. However, the greatest PHBV productivities were observed in the BCRs operated with glycerol and Ac-HAc (21.7 and 33.5 g PHBV m− 3 d− 1, respectively). Glycerol supply induced the highest molar ratio (23%) of the homopolymer 3-hydroxyvalerate in the composition of PHBV. In addition, the specific cell content of CoQ10 ranged from 0.4 to 1 mg g− 1. This work constitutes, to the best of our knowledge, the first study combining N2O abatement with the simultaneous production of multiple bioproducts, which pave the way to the development of greenhouse gas biorefineries for climate change mitigation.Ministerio de Economía, Industria y Competitividad (Project CTM2015-70442-R and Red NOVEDAR
Nitrous Oxide Abatement Coupled with Biopolymer Production As a Model GHG Biorefinery for Cost-Effective Climate Change Mitigation
Producción CientíficaN2O represents ∼6% of the global greenhouse gas emission inventory and the most important O3-depleting substance emitted in this 21st century. Despite its environmental relevance, little attention has been given to cost-effective and environmentally friendly N2O abatement methods. Here we examined, the potential of a bubble column (BCR) and an internal loop airlift (ALR) bioreactors of 2.3 L for the abatement of N2O from a nitric acid plant emission. The process was based on the biological reduction of N2O by Paracoccus denitrificans using methanol as a carbon/electron source. Two nitrogen limiting strategies were also tested for the coproduction of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) coupled with N2O reduction. High N2O removal efficiencies (REs) (≈87%) together with a low PHBV cell accumulation were observed in both bioreactors in excess of nitrogen. However, PHBV contents of 38–64% were recorded under N limiting conditions along with N2O-REs of ≈57% and ≈84% in the ALR and BCR, respectively. Fluorescence in situ hybridization analyses showed that P. denitrificans was dominant (>50%) after 6 months of experimentation. The successful abatement of N2O concomitant with PHBV accumulation confirmed the potential of integrating biorefinery concepts into biological gas treatment for a cost-effective GHG mitigation.Ministerio de Economía, Industria y Competitividad (Proyect CTM2015-70442-R and Red NOVEDAR CTQ2014-51693-REDC
The implausibility of ‘usual care’ in an open system: sedation and weaning practices in Paediatric Intensive Care Units (PICUs) in the United Kingdom (UK)
Background: The power of the randomised controlled trial depends upon its capacity to operate in a closed
system whereby the intervention is the only causal force acting upon the experimental group and absent in the
control group, permitting a valid assessment of intervention efficacy. Conversely, clinical arenas are open systems
where factors relating to context, resources, interpretation and actions of individuals will affect implementation and
effectiveness of interventions. Consequently, the comparator (usual care) can be difficult to define and variable in
multi-centre trials. Hence outcomes cannot be understood without considering usual care and factors that may
affect implementation and impact on the intervention.
Methods: Using a fieldwork approach, we describe PICU context, ‘usual’ practice in sedation and weaning from
mechanical ventilation, and factors affecting implementation prior to designing a trial involving a sedation and
ventilation weaning intervention. We collected data from 23 UK PICUs between June and November 2014 using
observation, individual and multi-disciplinary group interviews with staff.
Results: Pain and sedation practices were broadly similar in terms of drug usage and assessment tools. Sedation
protocols linking assessment to appropriate titration of sedatives and sedation holds were rarely used (9 % and 4 %
of PICUs respectively). Ventilator weaning was primarily a medical-led process with 39 % of PICUs engaging senior
nurses in the process: weaning protocols were rarely used (9 % of PICUs). Weaning methods were variably based
on clinician preference. No formal criteria or use of spontaneous breathing trials were used to test weaning
readiness. Seventeen PICUs (74 %) had prior engagement in multi-centre trials, but limited research nurse
availability. Barriers to previous trial implementation were intervention complexity, lack of belief in the evidence and
inadequate training. Facilitating factors were senior staff buy-in and dedicated research nurse provision.
Conclusions: We examined and identified contextual and organisational factors that may impact on the
implementation of our intervention. We found usual practice relating to sedation, analgesia and ventilator weaning
broadly similar, yet distinctively different from our proposed intervention, providing assurance in our ability to
evaluate intervention effects. The data will enable us to develop an implementation plan; considering these factors
we can more fully understand their impact on study outcomes
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A simple device for multiplex ELISA made from melt-extruded plastic microcapillary film
We present a simple device for multiplex quantitative enzyme-linked immunosorbant assays (ELISA) made from a novel melt-extruded microcapillary film (MCF) containing a parallel array of 200µm capillaries along its length. To make ELISA devices different protein antigens or antibodies were immobilised inside individual microcapillaries within long reels of MCF extruded from fluorinated ethylene propylene (FEP). Short pieces of coated film were cut and interfaced with a pipette, allowing sequential uptake of samples and detection solutions into all capillaries from a reagent well. As well as being simple to produce, these FEP MCF devices have excellent light transmittance allowing direct optical interrogation of the capillaries for simple signal quantification. Proof of concept experiments demonstrate both quantitative and multiplex assays in FEP MCF devices using a standard direct ELISA procedure and read using a flatbed scanner. This new multiplex immunoassay platform should find applications ranging from lab detection to point-of-care and field diagnostics
Metrics for Differential Privacy in Concurrent Systems
Part 3: Security AnalysisInternational audienceOriginally proposed for privacy protection in the context of statistical databases, differential privacy is now widely adopted in various models of computation. In this paper we investigate techniques for proving differential privacy in the context of concurrent systems. Our motivation stems from the work of Tschantz et al., who proposed a verification method based on proving the existence of a stratified family between states, that can track the privacy leakage, ensuring that it does not exceed a given leakage budget. We improve this technique by investigating a state property which is more permissive and still implies differential privacy. We consider two pseudometrics on probabilistic automata: The first one is essentially a reformulation of the notion proposed by Tschantz et al. The second one is a more liberal variant, relaxing the relation between them by integrating the notion of amortisation, which results into a more parsimonious use of the privacy budget. We show that the metrical closeness of automata guarantees the preservation of differential privacy, which makes the two metrics suitable for verification. Moreover we show that process combinators are non-expansive in this pseudometric framework. We apply the pseudometric framework to reason about the degree of differential privacy of protocols by the example of the Dining Cryptographers Protocol with biased coins
A Metabolomic Approach To Detect Effects of Salmon Farming on Wild Saithe (Pollachius virens) Populations
A metabolomics approach was used to analyze effects of salmon farming on wild saithe (Pollachius virens) populations. Saithe fish were captured at two salmon farms and at two control locations around the island of Hitra, Norway. Changes in diet seem to drive changes in metabolic status of fishes. The liver and muscle tissues, from the fishes captured around the farm, showed higher levels of lactate and certain amino acids (glutamine, glutamate, and alanine) and lower levels of glucose and choline than the fishes captured in the control locations, far from the farm locations. The higher levels of lactate and amino acids could be related to the facility of obtaining food around the farm and the deficit in choline to the deficit of this nutrient in the salmon feed. At each location the fish were captured with either benthic gill nets and automatic jigging machines, and this feature showed also variations in different metabolites.This research was funded by the Norwegian Seafood Research Fund through the project “Evaluation of actions to promote sustainable coexistence between salmon culture and coastal fisheries, ProCoEx” (Project 900772). K.T.-G. was supported by a grant from Iceland, Liechtenstein, and Norway through the EEA Financial Mechanism
An Exactly Conservative Integrator for the n-Body Problem
The two-dimensional n-body problem of classical mechanics is a non-integrable
Hamiltonian system for n > 2. Traditional numerical integration algorithms,
which are polynomials in the time step, typically lead to systematic drifts in
the computed value of the total energy and angular momentum. Even symplectic
integration schemes exactly conserve only an approximate Hamiltonian. We
present an algorithm that conserves the true Hamiltonian and the total angular
momentum to machine precision. It is derived by applying conventional
discretizations in a new space obtained by transformation of the dependent
variables. We develop the method first for the restricted circular three-body
problem, then for the general two-dimensional three-body problem, and finally
for the planar n-body problem. Jacobi coordinates are used to reduce the
two-dimensional n-body problem to an (n-1)-body problem that incorporates the
constant linear momentum and center of mass constraints. For a four-body
choreography, we find that a larger time step can be used with our conservative
algorithm than with symplectic and conventional integrators.Comment: 17 pages, 3 figures; to appear in J. Phys. A.: Math. Ge
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