ADMS-AIRPORT: MODEL INTER-COMPARISIONS AND MODEL VALIDATION

The functionality of ADMS-Airport and details of its use in the Model Inter-comparison Study of the Project for the Sustainable Development of Heathrow Airport (PSDH) have previously been presented, Carruthers et al (2007). A distinguishing feature is the treatment of jet engine emissions as moving jet sources rather than averaging these emissions into volume sources as is the case in some other models. In this presentation two further studies are presented which each contribute to the overall evaluation of the model. In the Heathrow study on adding capacity (third runway) further comparisons have been made between the measured NOx, NO2 and PM10 concentrations from the large number of automatic monitoring sites located in the neighbourhood of Heathrow Airport and the ADMS-Airport predictions. A range of tools is employed with which to present the comparisons including the BOOT validation toolkit and concentration wind roses. In the CAEPport study a fictional but realistic airport was ‘constructed’ for a model inter-comparison study the purposes of which were (i) to determine that air quality airport models put forward for CAEP (ICAO’s Committee on Environmental Aviation Protection) analysis are ‘sufficiently robust, rigorous and transparent’ for forthcoming CAEP analyses and (ii) to explain differences in the models. The study included consideration of both emissions and air pollution concentrations however the focus here will be on the modelled concentrations. Results for ADMS-Airport from this study will be presented along with those of the other participating models – EDMS, LASPORT and ALAQS

The time required for water attack at the phosphorus atom of simple phosphodiesters and of DNA

Phosphodiester linkages, including those that join the nucleotides of DNA, are highly resistant to spontaneous hydrolysis. The rate of water attack at the phosphorus atom of phosphodiesters is known only as an upper limit, based on the hydrolysis of the dimethyl phosphate anion. That reaction was found to proceed at least 99% by C–O cleavage, at a rate suggesting an upper limit of 10−15 s−1 for P–O cleavage of phosphodiester anions at 25°C. To evaluate the rate enhancement produced by P–O cleaving phosphodiesterases such as staphylococcal nuclease, we decided to establish the actual value of the rate constant for P–O cleavage of a simple phosphodiester anion. In dineopentyl phosphate, C–O cleavage is sterically precluded so that hydrolysis occurs only by P–O cleavage. Measurements at elevated temperatures indicate that the dineopentyl phosphate anion undergoes hydrolysis in water with a t1/2 of 30,000,000 years at 25°C, furnishing an indication of the resistance of the internucleotide linkages of DNA to water attack at phosphorus. These results imply that staphylococcal nuclease (kcat = 95 s−1) enhances the rate of phosphodiester hydrolysis by a factor of ≈1017. In alkaline solution, thymidylyl-3′-5′-thymidine (TpT) has been reported to decompose 105-fold more rapidly than does dineopentyl phosphate. We find however that TpT and thymidine decompose at similar rates and with similar activation parameters, to a similar set of products, at pH 7 and in 1 M KOH. We infer that the decomposition of TpT is initiated by the breakdown of thymidine, not by phosphodiester hydrolysis

Explaining the relationship between number line estimation and mathematical achievement: the role of visuomotor integration and visuospatial skills

Performance on number line tasks, typically used as a measure of numerical representations, are reliably related to children’s mathematical achievement. However, recent debate has questioned what precisely performance on the number line estimation task measures. Specifically, there has been a suggestion that this task may measure not only numerical representations but also proportional judgment skills; if this is the case, then individual differences in visuospatial skills, not just the precision of numerical representations, may explain the relationship between number line estimation and mathematical achievement. The current study investigated the relationships among visuospatial skills, visuomotor integration, number line estimation, and mathematical achievement. In total, 77 children were assessed using a number line estimation task, a standardized measure of mathematical achievement, and tests of visuospatial skills and visuomotor integration. The majority of measures were significantly correlated. In addition, the relationship between one metric from the number line estimation task (R2LIN) and mathematical achievement was fully explained by visuomotor integration and visuospatial skill competency. These results have important implications for understanding what the number line task measures as well as the choice of number line metric for research purposes

Effects of multiple-bond ruptures on kinetic parameters extracted from force spectroscopy measurements: Revisiting biotin-streptavidin interactions

Force spectroscopy measurements of the rupture of the molecular bond between biotin and streptavidin often results in a wide distribution of rupture forces. We attribute the long tail of high rupture forces to the nearly simultaneous rupture of more than one molecular bond. To decrease the number of possible bonds, we employed hydrophilic polymeric tethers to attach biotin molecules to the atomic force microscope probe. It is shown that the measured distributions of rupture forces still contain high forces that cannot be described by the forced dissociation from a deep potential well. We employed a recently developed analytical model of simultaneous rupture of two bonds connected by polymer tethers with uneven length to fit the measured distributions. The resulting kinetic parameters agree with the energy landscape predicted by molecular dynamics simulations. It is demonstrated that when more than one molecular bond might rupture during the pulling measurements there is a noise-limited range of probe velocities where the kinetic parameters measured by force spectroscopy correspond to the true energy landscape. Outside this range of velocities, the kinetic parameters extracted by using the standard most probable force approach might be interpreted as artificial energy barriers that are not present in the actual energy landscape. Factors that affect the range of useful velocities are discussed

Feasibility of percutaneous posterolateral spinal fusion with recombinant bone morphogenetic protein-2 (rhBMP-2): a comparison with standard methods using an animal model study

Background Context: The clinical application of recombinant bone morphogenetic protein in spinal surgery has been shown to be safe and effective. However, its use in minimally invasive spine surgery has been limited to anterior interbody fusion procedures. To date, no study has evaluated the feasibility of percutaneous posterolateral fusion in the spine utilizing recombinant bone morphogenetic protein-2 (rhBMP-2). Purpose: To evaluate the feasibility of percutaneous posterolateral fusion in the spine utilizing rhBMP-2. Study Design: Animal study. Methods: This is an animal research model involving 32 New Zealand white rabbits stratified into 4 study groups: control, autogenous iliac crest bone graft (ICBG), demineralized bone matrix (DBM), and rhBMP-2 groups, with 8 study subjects per group. The rhBMP-2 group was subdivided into the open technique (right side) and the percutaneous technique groups (left side). Fusion was graded at 6 weeks and 3 months after plain radiography, computed tomography, and clinical assessment with the following grading system: grade A, no bone formation; grade B, non-bridging bone formation; grade C, fusion; and grade D, fusion with ectopic bone formation. Results: No fusion was noted in the placebo and the DBM groups. However, in the DBM group, bone formation occurred in 37.5% of the subjects. The rhBMP-2 group had a higher fusion rate compared with the ICBG group at 6 weeks and 3 months. The fusion rate for the ICBG, the rhBMP-2 (open), and the rhBMP-2 (percutaneous) groups were 37.5%, 87.5%, and 50.0% at 6 weeks and 50.0%, 100.0%, and 62.5% at 3 months, respectively. Ectopic bone formation occurred in 12.5% of the cases in the rhBMP-2 (percutaneous) group and in 25.0% of the cases in the rhBMP-2 (open) group. Conclusions: Usage of rhBMP-2 is feasible for percutaneous posterolateral fusion of the lumbar spine in this animal model. However, a more precise delivery system might improve the fusion rate when the percutaneous technique is used. A significant rate of ectopic bone formation occurred when rhBMP-2 was used

Phenotypic Characterization of a Genetically Diverse Panel of Mice for Behavioral Despair and Anxiety

Animal models of human behavioral endophenotypes, such as the Tail Suspension Test (TST) and the Open Field assay (OF), have proven to be essential tools in revealing the genetics and mechanisms of psychiatric diseases. As in the human disorders they model, the measurements generated in these behavioral assays are significantly impacted by the genetic background of the animals tested. In order to better understand the strain-dependent phenotypic variability endemic to this type of work, and better inform future studies that rely on the data generated by these models, we phenotyped 33 inbred mouse strains for immobility in the TST, a mouse model of behavioral despair, and for activity in the OF, a model of general anxiety and locomotor activity.We identified significant strain-dependent differences in TST immobility, and in thigmotaxis and distance traveled in the OF. These results were replicable over multiple testing sessions and exhibited high heritability. We exploited the heritability of these behavioral traits by using in silico haplotype-based association mapping to identify candidate genes for regulating TST behavior. Two significant loci (-logp >7.0, gFWER adjusted p value <0.05) of approximately 300 kb each on MMU9 and MMU10 were identified. The MMU10 locus is syntenic to a major human depressive disorder QTL on human chromosome 12 and contains several genes that are expressed in brain regions associated with behavioral despair.We report the results of phenotyping a large panel of inbred mouse strains for depression and anxiety-associated behaviors. These results show significant, heritable strain-specific differences in behavior, and should prove to be a valuable resource for the behavioral and genetics communities. Additionally, we used haplotype mapping to identify several loci that may contain genes that regulate behavioral despair

Multi-messenger searches via IceCube’s high-energy neutrinos and gravitational-wave detections of LIGO/Virgo

We summarize initial results for high-energy neutrino counterpart searches coinciding with gravitational-wave events in LIGO/Virgo\u27s GWTC-2 catalog using IceCube\u27s neutrino triggers. We did not find any statistically significant high-energy neutrino counterpart and derived upper limits on the time-integrated neutrino emission on Earth as well as the isotropic equivalent energy emitted in high-energy neutrinos for each event