2,352 research outputs found
Modelling gap-size distribution of parked cars using random-matrix theory
We apply the random-matrix theory to the car-parking problem. For this
purpose, we adopt a Coulomb gas model that associates the coordinates of the
gas particles with the eigenvalues of a random matrix. The nature of
interaction between the particles is consistent with the tendency of the
drivers to park their cars near to each other and in the same time keep a
distance sufficient for manoeuvring. We show that the recently measured
gap-size distribution of parked cars in a number of roads in central London is
well represented by the spacing distribution of a Gaussian unitary ensemble.Comment: 7 pages, 1 figur
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Chromatin remodeling protein HELLS is critical for retinoblastoma tumor initiation and progression.
Retinoblastoma is an aggressive childhood cancer of the developing retina that initiates by biallelic RB1 gene inactivation. Tumor progression in retinoblastoma is driven by epigenetics, as retinoblastoma genomes are stable, but the mechanism(s) that drive these epigenetic changes remain unknown. Lymphoid-specific helicase (HELLS) protein is an epigenetic modifier directly regulated by the RB/E2F pathway. In this study, we used novel genetically engineered mouse models to investigate the role of HELLS during retinal development and tumorigenesis. Our results indicate that Hells-null retinal progenitor cells divide, undergo cell-fate specification, and give rise to fully laminated retinae with minor bipolar cells defects, but normal retinal function. Despite the apparent nonessential role of HELLS in retinal development, failure to transcriptionally repress Hells during retinal terminal differentiation due to retinoblastoma (RB) family loss significantly contributes to retinal tumorigenesis. Loss of HELLS drastically reduced ectopic division of differentiating cells in Rb1/p107-null retinae, significantly decreased the incidence of retinoblastoma, delayed tumor progression, and increased overall survival. Despite its role in heterochromatin formation, we found no evidence that Hells loss directly affected chromatin accessibility in the retina but functioned as transcriptional co-activator of E2F3, decreasing expression of cell cycle genes. We propose that HELLS is a critical downstream mediator of E2F-dependent ectopic proliferation in RB-null retinae. Together with the nontoxic effect of HELLS loss in the developing retina, our results suggest that HELLS and its downstream pathways could serve as potential therapeutic targets for retinoblastoma
The detection of lubricating oil viscosity changes in gearbox transmission systems driven by sensorless variable speed drives using electrical supply parameters
Lubrication oil plays a decisive role to maintain a reliable and efficient operation of gear transmissions. Many offline methods have been developed to monitor the quality of lubricating oils. This work focus on developing a novel online method to diagnose oil degradation based on the measurements from power supply system to the gearbox. Experimental studies based on an 10kW industrial gearbox fed by a sensorless variable speed drive (VSD) shows that measurable changes in both static power and dynamic behaviour are different with lube oils tested. Therefore, it is feasible to use the static power feature to indicate viscosity changes at low and moderate operating speeds. In the meantime, the dynamic feature can separate viscosity changes for all different tested cases
Evaluating Diversity and Inclusion Content on Graduate Medical Education Websites.
UNLABELLED: Websites are important tools for programs to provide future residency applicants with freely accessible information regarding their program, including diversity, equity, and inclusion (DEI) initiatives.
OBJECTIVE: To describe the variability of DEI content in residency programs and compare DEI website content by specialty.
METHODS: Using the 2021 Accreditation Council for Graduate Medical Education (ACGME) list of residency programs, residency training websites were identified and evaluated. Information was extracted from program websites as indicators of DEI content. Chi-square analysis and one-way ANOVA were chosen to assess for statistical differences.
RESULTS: In total, 4644 program websites representing 26 specialties were assessed. Among all the programs, the average DEI completeness of a program website was 6.1±14.6% (range 0-100%). While 6.2% of all programs had a diversity webpage, only 13.3% included a commitment to DEI, and few programs (2.7%) provided information about underrepresented in medicine (URiM) faculty.
CONCLUSIONS: Graduate medical education programs can enhance information for current and prospective applicants about DEI initiatives on their websites. Including DEI initiatives on residency websites may improve diversity recruitment efforts
Impact of Symmetry on the Ferroelectric Properties of CaTiO₃ Thin Films
Epitaxial strain is a powerful tool to induce functional properties such as ferroelectricity in thin films of materials that do not possess ferroelectricity in bulk form. In this work, a ferroelectric state was stabilized in thin films of the incipient ferroelectric, CaTiO3, through the careful control of the biaxial strain state and TiO6 octahedral rotations. Detailed structural characterization was carried out by synchrotron x-ray diffraction and scanning transmission electron microscopy. CaTiO3 films grown on La0.18Sr0.82Al0.59Ta0.41O3 (LSAT) and NdGaO3 (NGO) substrates experienced a 1.1% biaxial strain state but differed in their octahedral tilt structures. A suppression of the out-of-plane rotations of the TiO6 octahedral in films grown on LSAT substrates resulted in a robust ferroelectric 14 mm phase with remnant polarization ~5 µC/cm2 at 10K and Tc near 140 K. In contrast, films grown on NGO substrates with significant octahedral tilting showed reduced polarization and Tc. These results highlight the key role played by symmetry in controlling the ferroelectric properties of perovskite oxide thin films
Erratum: Impact of Symmetry on the Ferroelectric Properties of CaTiO₃ Thin Films (Applied Physics Letters 106:162904 (2015))
There is a typo of the space group. All the Pnmb should be Pbnm (or Pnma). So the Glazer notation should be changed to (a-a-c+) for Pbnm space group on page 4 of the article. We have also noticed that the thermodynamic analysis of CaTiO3 thin film is not correct. The films are (001)PC-oriented or (101)-oriented. Therefore, there is no need to rotate the coordinate system (on page 4 of the article). By applying the thin film boundary condition, i.e., ε11 = ε22 = εs, ε21 = ε12 = 0; σ13 = σ23 = σ33 = σ31 = σ32 = 0, and minimizing the total free energy with respect to epitaxial strain, εs, a temperature-strain phase diagram is determined. All the strain and stress components should be in the original coordinate system. The corrected phase diagrams are shown in the figures below. For LSAT phase diagrams (Figs. 5(a) and 5(b)), the ferroelectric transition is better described using the Fmm2 phase because the calculated phase boundary is much closer to the experimental value than using the Aba2 phase. The NGO phase diagram, as shown in Fig. 5(c), is essentially the same as Gu’s orthorhombic Pbnm CaTiO3 film calculation, which is also (001)PC-oriented. All the other analysis and conclusions in the article are not affected. We apologize to the readers for the confusion that might have been caused. The authors would like to thank Ryan Haislmaier for pointing out the mistake
Report on findings on transportation and logistics of selected food value chains:Salmon to fillet case study
• Transportation has significant impact on food costs and the environment. It is a major contributor to carbon emissions, accounting for almost a quarter of the CO2 emissions in the EU, of which 30% is attributed to the food sector.
• This deliverable addresses the modelling of food chains’ transportation and logistics. It develops a robust model for policy support, which is applied to a specific case as a worked example. The approach can be used to model the transport and logistics of other food supply chains, given data availability.
• The mathematical modelling aims to optimise the cost and effectiveness of logistics operations. It also allows for the integration and consideration of environmental aspects within transportation, processing and distribution operations.
• Specifically, the deliverable focuses on the development of a logistics mathematical model using Atlantic salmon as an exemplary example of a globally integrated food supply chain. A Norwegian salmon exporter was engaged to supply data for validating the mathematical model.
• The model follows a multi-objective optimization approach that captures the trade-off between total logistics cost and the environment. It has two objectives. Firstly, to minimize total costs associated with transportation, fuel consumption, inventory holding, processing and residuals/waste. Secondly, to reduce CO2 emissions incurred by production at plants, transportation from suppliers to plants, and transportation from plants to customers.
• Constraints related to supply, processing capacity, storage capacity, demand, carbon emissions, inventory balancing, transportation capacity, and different modes of transportation between different types of plants and facilities are also consider within the model.
• Model development, validation and policy recommendation occurred in four stages: (i) mapping supply chain linkages and product flows, (ii) designing the mathematical model, (iii) data collection for parameters of the model and (iv) model validation and deriving policy recommendation.
• Before modeling, consultation with salmon supply chain actors occurred as a first step to map the supply chain linkages. This involved expert interviews with VALUMICS partners.
• Based on the mapping of the supply chain, a mathematical model was developed. However, given the complexity of the supply chain and the limited information that can be drawn from a single company which completely covers both the supply and the demand ends of the value chains, the model was divided into two stages (Model N1 and N2)
• First it optimises the supply chain network from salmon farms, abattoirs, primary processing plants, secondary processing plants and wholesalers so to meet the demand of the Secondary Processing Plants and Wholesalers for Fresh HOG (Head-on-Gutted) product (Model N1) (farm to wholesaler).
• Second, it addresses the supply chain from the secondary processing plants and wholesalers to retailers. The secondary processing plants process HOG into whole fillet, salmon by-products and some residual amount so to meet the demand of retailers (Model N2) (wholesaler to retailer).
• An additional model (Model M) allows for the optimisation of the overall supply chain network where, for example, a Company X tries to meet the demand of retailers in different time periods (farm to retailer).
• A transportation scenario analysis was also conducted by considering options for various maritime transportation routes from primary processing plant to secondary processing and primary processing plant to various wholesalers.
• The results from the three models highlight that it is essential for any company to optimise the overall supply chain network system (from salmon farms to retailers), as the total cost for model M is relatively much lower than the combined total cost of N1 and N2.
• Each model also shows that the supply chain network is sensitive to fuel cost and consequently, fuel consumption and distances between actors across the supply chain.
• Environmental impact is generally measured by fuel consumption during operations and in the case of food chain, transportation and distribution are important contributors via the use of fuel-based vehicles, sea vessels and/or airplanes.
• The scenarios analysis highlights the importance of adopting maritime transportation routes in terms of significantly reducing the total cost, fuel cost and overall carbon emission. Hence shifting certain logistics operations from road to maritime transportation from the perspective of economic and environmental benefits are advocated.
• For short to medium distances (vans, trucks, rails and sea vessels) that covers transportation trips to reach airport hubs and big cities, lowering CO2 emissions depends on the emissions ratio (the relative emissions impact of delivery vehicle when compared to personal vehicle – mostly applied in urban logistics) and customer density.
• For long distance transport (air), environmental improvement can be mainly achieved through technological development and this has been well supported by research dedicated specifically to address EU aviation industry challenges.
• The models are developed for a planning horizon consisting of discrete time periods, aiding the possibility of studying demand and supply uncertainty and its consequences in supply chain decision making. Hence, they help decision makers to identify the changes in a supply chain network when different transportation routes are adopted (for example whether maritime routes can be adopted or not in place of road/rail transportation, to address environmental concerns related to fuel consumption and carbon emissions).
• The models are valuable for policy makers in terms of understanding the costs and emissions associated with different food supply chains, as well as the effects of particular policy interventions and market developments (e.g. variation in demand, fuel costs, emission and waste constraints).
• They can aid supply chain managers to make decisions regarding the amountof inventory to be kept in different time periods.Aditjandra, P., De, A., M., Gorton, M., Hubbard, C., Pang, G., Mehta, S., Thakur, M., Richardson, M., Bogasson, S., Olafsdottir, G. (2019) Report on findings on transportation and logistics of selected food value chains. VALUMICS "Understanding Food Value Chains and Network Dynamics", funded by European Union's Horizon 2020 research and innovation programme GA No 727243. Deliverable: D7.1, Newcastle University, UK, 94 page
Aleuria Aurantia Lectin (AAL)-Reactive Immunoglobulin G Rapidly Appears in Sera of Animals following Antigen Exposure.
We have discovered an Aleuria Aurantia Lectin (AAL)-reactive immunoglobulin G (IgG) that naturally occurs in the circulation of rabbits and mice, following immune responses induced by various foreign antigens. AAL can specifically bind to fucose moieties on glycoproteins. However, most serum IgGs are poorly bound by AAL unless they are denatured or treated with glycosidase. In this study, using an immunogen-independent AAL-antibody microarray assay that we developed, we detected AAL-reactive IgG in the sera of all animals that had been immunized 1-2 weeks previously with various immunogens with and without adjuvants and developed immunogen-specific responses. All of these animals subsequently developed immunogen-specific immune responses. The kinetics of the production of AAL-reactive IgG in mice and rabbits were distinct from those of the immunogen-specific IgGs elicited in the same animals: they rose and fell within one to two weeks, and peaked between four to seven days after exposure, while immunogen-specific IgGs continued to rise during the same period. Mass spectrometric profiling of the Fc glycoforms of purified AAL-reactive IgGs indicates that these are mainly comprised of IgGs with core-fucosylated and either mono-or non-galactosylated Fc N-glycan structures. Our results suggest that AAL-reactive IgG could be a previously unrecognized IgG subset that is selectively produced at the onset of a humoral response
Statistical Properties of Charmonium Spectrum and a New Mechanism of J/\psi Suppression
The statistical properties of Charmonium energy spectrum determined by the
Bethe-Salpeter equation are investigated. It is found that the regular motion
of the system can be expected at a small value of color screening
mass but the chaotic motion at a large one. It is shown that the level mixing
due to color screening serves as a new mechanism resulting in the J/
suppression. Moreover, this kind of suppression can occur before the color
screening mass reaches its critical value for J/ dissociation. It implies
that a strong J/ suppression is possible in the absence of dissociation
of J/.Comment: 13 latex pages, 2 figures. Phys. Rev. C in pres
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