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Many-Body State and Dynamic Behaviour of the Pair-Correlation Function of a Small Bose–Einstein Condensate Confined in a Ring Potential
No full textWe investigate the many-body state and the static and the dynamic behaviour of the pair-correlation function of a Bose–Einstein condensate with a finite atom number, which is confined in a quasi-one-dimensional toroidal/annular potential, both for repulsive, and for attractive interactions. We link the dynamic pair-correlation function that we evaluate with the problem of quantum time crystals. For weak repulsive interatomic interactions and a finite number of atoms the pair-correlation function shows a periodic temporal behaviour, which disappears in the limit of a large atom number, in agreement with general arguments. Finally we provide some insight into older results of attractive interactions, where the time-crystalline behaviour exists only in the limit of a large atom number
The influence of oxygen partial pressure on the base oxide of chromia forming steels: The story prior to breakaway oxidation
Get PDFThe influence of pO2 on the base oxide formed on 304 L stainless steel has been investigated at 600 \ub0C. The alloy was exposed in 5%O2-95%N2 and 10%H2-20%H2O-Ar atmospheres and the initial stages of oxidation were analysed by TEM and EDX. In both environments, the thin scale consists of a Cr-rich oxide overlaid by a FeCrMn oxide. However, the subscale formed in H2-H2O is richer in Cr compared to the 5%O2-95%N2 case (∼90 cation% and ∼70 cation% respectively). The findings are in good agreement with thermodynamic calculations and can explain breakaway oxidation of marginal chromia forming steels in H2-H2O
How COVID-19 transformed the landscape of transportation research: an integrative scoping review and roadmap for future research
No full textIn the wake of the COVID-19 pandemic, scholars mobilized their efforts to address its far-reaching societal problems. With mobility restrictions being front and center of the pandemic, a new cohort of transportation science was developed within a short period of time. Here, we examine more than 400 studies related to COVID-19 published across transportation journals during 2020 and 2021. The aim is (i) to scope this newly developed segment of transportation research, (ii) outline the diversity of pandemic-related issues across various divisions of the transportation field and (iii) provide a roadmap for the future of this line of research. Common themes are identified and existing congruence and discrepancies across findings are discussed. Results show that although conventional methods of transportation research were adopted in virtually all COVID-19 studies, no pre-pandemic study was particularly instrumental in the development of this segment of transportation literature. The COVID-19 segment appears to have developed its own independent knowledge foundation, in that, it does not systemically and frequently look back at any particular pre-pandemic reference. Potential impacts of this newly developed segment on the metrics of transportation journals are quantified and discussed
Enzymatic debranching is a key determinant of the xylan-degrading activity of family AA9 lytic polysaccharide monooxygenases
Get PDFBackground: Previous studies have revealed that some Auxiliary Activity family 9 (AA9) lytic polysaccharide monooxygenases (LPMOs) oxidize and degrade certain types of xylans when incubated with mixtures of xylan and cellulose. Here, we demonstrate that the xylanolytic activities of two xylan-active LPMOs, TtLPMO9E and TtLPMO9G from Thermothielavioides terrestris, strongly depend on the presence of xylan substitutions. Results: Using mixtures of phosphoric acid-swollen cellulose (PASC) and wheat arabinoxylan (WAX), we show that removal of arabinosyl substitutions with a GH62 arabinofuranosidase resulted in better adsorption of xylan to cellulose, and enabled LPMO-catalyzed cleavage of this xylan. Furthermore, experiments with mixtures of PASC and arabinoglucuronoxylan from spruce showed that debranching of xylan with the GH62 arabinofuranosidase and a GH115 glucuronidase promoted LPMO activity. Analyses of mixtures with PASC and (non-arabinosylated) beechwood glucuronoxylan showed that GH115 action promoted LPMO activity also on this xylan. Remarkably, when WAX was incubated with\ua0Avicel instead of PASC in the presence of the GH62, both xylan and cellulose degradation by the LPMO9 were impaired, showing that the formation of cellulose–xylan complexes and their susceptibility to LPMO action also depend on the properties of the cellulose. These debranching effects not only relate to modulation of the cellulose–xylan interaction, which influences the conformation and rigidity of the xylan, but likely also affect the LPMO–xylan interaction, because debranching changes the architecture of the xylan surface. Conclusions: Our results shed new light on xylanolytic LPMO9 activity and on the functional interplay and possible synergies between the members of complex lignocellulolytic enzyme cocktails. These findings will be relevant for the development of future lignocellulolytic cocktails and biomaterials
Numerical modeling of a wire mesh for aerodynamic noise reduction
No full textA novel wire mesh consisting of very fine wires and pores is numerically investigated for the purpose of noise reduction. To develop a numerical model for this wire mesh, a set of experimental flow-field data has been deployed for the model validation. The experimental data were measured with only 22% of the wind-tunnel cross section covered by the wire mesh, taking into account the vortex shedding from both sides of the wire-mesh fairing. It is found that existing wire-mesh models using a damping-type source term proportional to the square of flow velocity do not perform well in modeling this novel wire mesh. To tackle this issue, an improvement is proposed by additionally introducing a linear term to account for the permeability of the wire mesh, based on another set of experiments with the wind-tunnel cross section fully covered by the wire mesh. The proposed model is then validated against the experimental data, demonstrating its capability in modeling the wire mesh. Subsequently, the model is applied to a tandem cylinder configuration. Results show that a wide but short-span wire mesh significantly reduces the dominant tone of tandem cylinders, noise at higher frequencies, as well as the overall sound pressure levels
Mindful SensoriMotor Therapy combined with brain modulation for the treatment of pain in individuals with disarticulation or nerve injuries: a single-arm clinical trial
Get PDFINTRODUCTION: Neuropathic pain is a complex and demanding medical condition that is often difficult to treat. Regardless of the cause, the impairment, lesion or damage to the nervous system can lead to neuropathic pain, such as phantom limb pain (PLP). No treatment has been found widely effective for PLP, but plasticity-guided therapies have shown the least severe side effects in comparison to pharmacological or surgical interventions. Phantom motor execution (PME) is a plasticity-guided intervention that has shown promising results in alleviating PLP. The potential mechanism underlying the effectiveness of PME can be explained by the Stochastic Entanglement hypothesis for neurogenesis of neuropathic pain resulting from sensorimotor impairment. We have built on this hypothesis to investigate the efficacy of enhancing PME interventions by using phantom motor imagery to facilitate execution and with the addition of sensory training. We refer to this new treatment concept as Mindful SensoriMotor Therapy (MiSMT). In this study, we further complement MiSMT with non-invasive brain modulation, specifically transcranial direct current stimulation (tDCS), for the treatment of neuropathic pain in patients with disarticulation or peripheral nerve injury. METHODS AND ANALYSIS: This single-arm clinical trial investigates the efficacy of MiSMT and tDCS as a treatment of neuropathic pain resulting from highly impaired extremity or peripheral nerve injury in eight participants. The study consists of 12 sessions of MiSMT with anodal tDCS in the motor cortex, pretreatment and post-treatment assessments, and follow-up sessions (up to 6 months). The primary outcome is the change in pain intensity as measured by the Pain Rating Index between the first and last treatment sessions. ETHICS AND DISSEMINATION: The study is performed under the approval of the governing ethical committee in Sweden (approval number 2020-07157) and in accordance with the Declaration of Helsinki. TRIAL REGISTRATION NUMBER: NCT04897425
Insights from modeling renewable electricity systems and developing hydropower models
No full textOne strategy for reaching a carbon-neutral electricity system is a large-scale deployment of wind and solar power. However, electricity systems with high shares of wind and solar power rely on other technologies, e.g., transmission and hydropower, to ensure that demand can be met at all times despite weather-dependent wind and solar power production. Moreover,the deployment of some technologies may be limited by public concern and land availability, which could increase the cost of decarbonizing electricity systems.To analyze designs and costs for future electricity systems with high shares of renewables, energy system models are crucial. In such models, the representation of hydropower is often significantly simplified, overestimating how flexibly hydropower can operate and, thereby, the hydropower’s ability to complement wind and solar power production.This thesis has two overarching aims addressed separately in the two appended papers. First, to explore how deployment limits on wind and solar power, transmission, and nuclear power each affect the cost of future carbon-neutral electricity and how it differs between the Middle East and North Africa region (MENA) and Europe (Paper A). Second, to investigate theaccuracy of the hydropower representations used in energy system models and to develop a method for a more accurate hydropower representation (Paper B).In Paper A, we use an energy system model to show that the cost of a carbon-neutral electricity system is considerably lower in MENA than in Europe, which we link to MENA’s better wind and solar resource potential.Also, limiting the deployment of wind and solar power, transmission, or nuclear power can significantly affect system costs. However, the effect is markedly different in the two regions.Paper B examines how realistic different hydropower representations are by developing hydropower optimization models with different levels of detail and comparing them. We find that simple hydropower representations, such as those often used in energy system models, result in unrealistic production profiles and exaggerate the flexibility that hydropower can provide. In addition, we contribute a novel computationally efficient hydropower model that entails a more realistic hydropower production
SWATH-based quantitative proteomics gives insight into a significant proteome shift in UCB-1 pistachio rootstock under salt stress
No full textThe hybrid pistachio rootstock UCB-1 is especially tolerant to abiotic stresses including salinity. However, the effect of salinity on its whole proteome is obscure, which limits our ability to develop high-confident protein biomarkers to facilitate the genetic improvement of pistachio cultivars with enhanced salt-tolerance. In the present study, using sequential window acquisition of all theoretical mass spectra (SWATH-MS) technology, the expression of 1150 proteins was quantified, with the expression of 459 proteins significantly impacted by salt exposure. Functional enrichment determined that salinity stress increases the level of proteins associated with response to salt stress and reduces the level of ribosomal subunits. We used KEGG pathway enrichment analysis to link salt exposure with a set of alterations in several pathways including ribosome components, biosynthesis of phenylpropanoids, and carbon fixation in photosynthetic organisms. To track the potential consequences of protein alteration with more crucial biological functions in the enriched pathways, the incorporation of SWATH-MS data and protein-protein interactions (PPIs) analysis were then conducted. Centrality analysis of the three top-ranked enriched pathways highlighted that any alterations in the abundance of EMB3010, PA2, NAD-ME1, and PGAM proteins may result in desirable consequences on salt tolerance in UCB-1. Therefore, centrality analysis of whole proteome survey-derived responsive PPIs was useful in the identification, prioritization, and selection of potential biomarker candidates by which the need for expensive and time-consuming experimental validation will be minimized. At the early selection stages in tree breeding programs, integration of proteomics-generated resources with conventional programs can assist in developing fast selection assays
Performance and evolution of cold spray Cr-coated optimized ZIRLO™ claddings under simulated loss-of-coolant accident conditions
Get PDFThe performance of Cr-coated Optimized ZIRLO™ as accident tolerant fuel cladding material for pressurized water reactors (PWRs) is assessed. The coating oxidation mechanisms, oxide stability, and the transformation of the Cr-coating/Optimized ZIRLO™ interface are among the studied phenomena. For this purpose, samples were exposed at 1200\ub0C in steam for 3 min, 20 min and 40 min. As-fabricated coated claddings, plus specimens tested in autoclave at 415\ub0C for 90 days in simulated PWR water chemistry were employed for comparison. Characterization techniques such as scanning electron microscopy, energy dispersive x-ray spectroscopy, electron backscattered diffraction, and transmission electron microscopy were used to determine the chemistry and crystalline structure of the various phases formed during the different exposures. When exposed to loss-of-coolant accident (LOCA) conditions for 40 min, a layer of Cr2O3\ua0up to 8 \ub5m thick was measured on the outer surface of the Cr-coating. No significant oxidation of the underlaying Optimized ZIRLO™ alloy occurred, and the applied coating appears to be very effective at delaying the cladding degradation under accident conditions. At the coating-substrate interface, a 1–2 \ub5m thick layer of (Cr,Fe)2Zr Laves phase was found. The presence of this phase appears to have no detrimental effects on the coating performance, and it might play a role in slowing down the dissolution of the coating into the substrate. ZrO2\ua0particles were frequently found at grain boundaries in the coating after exposure to LOCA conditions. For longer exposure time, these particles are expected to grow into a ZrO2-network, creating a fast diffusion path for O, and compromising the oxidation protection offered by the coating
GOALS-JWST: NIRCam and MIRI Imaging of the Circumnuclear Starburst Ring in NGC 7469
Get PDFWe present James Webb Space Telescope (JWST) imaging of NGC 7469 with the Near-Infrared Camera and the Mid-InfraRed Instrument. NGC 7469 is a nearby, z = 0.01627, luminous infrared galaxy that hosts both a Seyfert Type-1.5 nucleus and a circumnuclear starburst ring with a radius of ∼0.5 kpc. The new near-infrared (NIR) JWST imaging reveals 66 star-forming regions, 37 of which were not detected by Hubble Space Telescope (HST) observations. Twenty-eight of the 37 sources have very red NIR colors that indicate obscurations up to A v ∼ 7 and a contribution of at least 25% from hot dust emission to the 4.4 μm band. Their NIR colors are also consistent with young (<5 Myr) stellar populations and more than half of them are coincident with the mid-infrared (MIR) emission peaks. These younger, dusty star-forming regions account for ∼6% and ∼17% of the total 1.5 and 4.4 μm luminosity of the starburst ring, respectively. Thanks to JWST, we find a significant number of young dusty sources that were previously unseen due to dust extinction. The newly identified 28 young sources are a significant increase compared to the number of HST-detected young sources (4-5). This makes the total percentage of the young population rise from ∼15% to 48%. These results illustrate the effectiveness of JWST in identifying and characterizing previously hidden star formation in the densest star-forming environments around active galactic nuclei (AGN)