What cost reslience?

Air traffic management research lacks a framework for modelling the cost of resilience during disturbance. There is no universally accepted metric for cost resilience. The design of such a framework is presented and the modelling to date is reported. The framework allows performance assessment as a function of differential stakeholder uptake of strategic mechanisms designed to mitigate disturbance. Advanced metrics, cost- and non-cost-based, disaggregated by stakeholder subtypes, will be deployed. A new cost resilience metric is proposed

Hub operations delay recovery based on cost optimisation - Dynamic cost indexing and waiting for passengers strategies

In this paper, two strategies for airlines’ operations at a hub are combined and analysed: dynamic cost indexing, to recover delay, and waiting for connecting passengers at the hub. Agent Based Modelling techniques have been used to model the airlines’ operations considering detailed passenger’s itineraries, an extended arrival manager operation with slot negotiation, and delay and uncertainty at different phases of the flights. Results show that, when optimising the total cost, there is a trade-off between connecting and non-connecting passengers with respect to the gate to gate trip time. Waiting for passengers arises as an interesting technique when minimising airline operating costs

Comportamiento biológico intraarticular de distintos aloinjertos tendinosos: estudio experimental

Se ha efectuado un estudio experimental comparativo, con valoración macro y microscópica, de la supervivencia, dentro de la articulación de la rodilla del conejo, de tendones flexores sobre extensores y dentro de estos, entre tendones conservados en fresco, congelados, liofilizados y fijados en solución de glutaraldehido al 0,2%. Los tendones se mantuvieron libres en la articulación receptora durante periodos distintos de tiempo. Entre los resultados destaca la pérdida de volumen, en el tiempo, de la masa tendinosa (18% de despariciones totales, con un 28% de pérdida final global). Los tendones fijados en glutaraldehido fueron los que presentaron menor pérdida de volumen. Los tendones implantados en fresco y los congelados presentaron una mayor tasa de infección. La mejor respuesta de supervivencia se detectó en los tendones conservados en glutaraldehido y los congelados. Así mismo, tenían más posibilidades de sobrevivir los flexores que los extensores. Desde el punto de vista histológico, los tendones conservados en fresco desencadenaron una mayor respuesta inflamatoria, con gran alteración estructural. Desde el punto de vista microscópico no se han hallado diferencias significativas entre flexores y extensores.Different groups of flexor and extensor tendons have been compared in their abitihty survive within the rabbit knee joint. Tendons were grouped and compared according four different storage procedures like freezing, lyophylization and fixation in 0,2% glutaraldehid. Some of them were used in fresh. All tendons have been kept inside the joint as free graft. All specimens lost weight along the study (18% of total loosing of specimen, and 28% of global loosing). Tendons fixed in disclosed less loosing of volume. Allograft infection was related to the method o glutaraildehid of storage, relationship being statistically significant (fresh tendons and frozen tendons were infected more easily). The best survival was found in both frozen and glutaraldehid fixed tendons. Flexor tendons show more chances of survival than extensors tendons. Histologically, fresh tendons disclosed the greatest inflammatory reaction. Opposite to the macroscopic findings, there were no significant differences between flexors and extensors tendons in the microscopical study

Time-domain THz spectroscopy reveals coupled protein-hydration dielectric response in solutions of native and fibrils of human lyso-zyme

Here we reveal details of the interaction between human lysozyme proteins, both native and fibrils, and their water environment by intense terahertz time domain spectroscopy. With the aid of a rigorous dielectric model, we determine the amplitude and phase of the oscillating dipole induced by the THz field in the volume containing the protein and its hydration water. At low concentrations, the amplitude of this induced dipolar response decreases with increasing concentration. Beyond a certain threshold, marking the onset of the interactions between the extended hydration shells, the amplitude remains fixed but the phase of the induced dipolar response, which is initially in phase with the applied THz field, begins to change. The changes observed in the THz response reveal protein-protein interactions me-diated by extended hydration layers, which may control fibril formation and may have an important role in chemical recognition phenomena

Continuous quantum measurements of a particle in a Paul trap

We calculate the propagator of a particle caught in a Paul trap and subject to the continuous quantum measurement of its position. The probabilities of the measurement outputs, the possible trajectories of the particle, are also found. This enables us to propose a series of experiments that would allow to confront the predictions of one of the models that describe the interaction between a measured quantum system and measuring device, namely the so called Restricted Path-Integral Formalism, with the experiment.Comment: Latex file, 10 page

Mutagenesis of Trichoderma reesei endoglucanase I: impact of expression host on activity and stability at elevated temperatures.

BackgroundTrichoderma reesei is a key cellulase source for economically saccharifying cellulosic biomass for the production of biofuels. Lignocellulose hydrolysis at temperatures above the optimum temperature of T. reesei cellulases (~50°C) could provide many significant advantages, including reduced viscosity at high-solids loadings, lower risk of microbial contamination during saccharification, greater compatibility with high-temperature biomass pretreatment, and faster rates of hydrolysis. These potential advantages motivate efforts to engineer T. reesei cellulases that can hydrolyze lignocellulose at temperatures ranging from 60-70°C.ResultsA B-factor guided approach for improving thermostability was used to engineer variants of endoglucanase I (Cel7B) from T. reesei (TrEGI) that are able to hydrolyze cellulosic substrates more rapidly than the recombinant wild-type TrEGI at temperatures ranging from 50-70°C. When expressed in T. reesei, TrEGI variant G230A/D113S/D115T (G230A/D113S/D115T Tr_TrEGI) had a higher apparent melting temperature (3°C increase in Tm) and improved half-life at 60°C (t1/2 = 161 hr) than the recombinant (T. reesei host) wild-type TrEGI (t1/2 = 74 hr at 60°C, Tr_TrEGI). Furthermore, G230A/D113S/D115T Tr_TrEGI showed 2-fold improved activity compared to Tr_TrEGI at 65°C on solid cellulosic substrates, and was as efficient in hydrolyzing cellulose at 60°C as Tr_TrEGI was at 50°C. The activities and stabilities of the recombinant TrEGI enzymes followed similar trends but differed significantly in magnitude depending on the expression host (Escherichia coli cell-free, Saccharomyces cerevisiae, Neurospora crassa, or T. reesei). Compared to N.crassa-expressed TrEGI, S. cerevisiae-expressed TrEGI showed inferior activity and stability, which was attributed to the lack of cyclization of the N-terminal glutamine in Sc_TrEGI and not to differences in glycosylation. N-terminal pyroglutamate formation in TrEGI expressed in S. cerevisiae was found to be essential in elevating its activity and stability to levels similar to the T. reesei or N. crassa-expressed enzyme, highlighting the importance of this ubiquitous modification in GH7 enzymes.ConclusionStructure-guided evolution of T. reesei EGI was used to engineer enzymes with increased thermal stability and activity on solid cellulosic substrates. Production of TrEGI enzymes in four hosts highlighted the impact of the expression host and the role of N-terminal pyroglutamate formation on the activity and stability of TrEGI enzymes