Diffusion-annihilation dynamics in one spatial dimension

We discuss a reaction-diffusion model in one dimension subjected to an external driving force. Each lattice site may be occupied by at most one particle. The particles hop with asymmetric rates (the sum of which is one) to the right or left nearest neighbour site if it is vacant, and annihilate with rate one if it is occupied. We compute the long time behaviour of the space dependent average density in states where the initial density profiles are step functions. We also compute the exact time dependence of the particle density for uncorrelated random initial conditions. The representation of the uncorrelated random initial state and also of the step function profile in terms of free fermions allows the calculation of time-dependent higher order correlation functions. We outline the procedure using a field theoretic approach.Comment: 26 pages, 1 Postscript figure, uses epsf.st

Supersize It! Developing a Supercytoplast Through Platelet Fusion

Stem cell research opens a wide range of possibilities from lab-grown tissues for medical purposes to cloned animals for livestock production. The issue with one of the most popular forms of cell recombination into a stem cell, known as somatic cell nuclear transfer (SCNT), is that it requires an oocyte. The requirement of an oocyte is often the host of public scrutiny for its economic and ethical issues. Platelets may offer a less expensive and more accessible alternative to oocytes as sources of naturally enucleated cells. Thus, the objective of this explorative research project is to isolate and fuse platelets to form a large body of cytoplasm, which could be used to receive a donated somatic nucleus for recombination. Blood samples were collected first from a horse and then from cattle. The whole blood was centrifuged to create a density gradient, and then the platelets were isolated using a commercially available protocol (Abcam, Cambridge, MA) for the isolation of human platelets. Once isolated, the platelets were diluted using an RPMI solution to four dilutions using the volumetric ratio of ml of platelet-rich plasma (PRP) to ml of RPMI solution. The dilutions were 1:10, 1:100, 1:1000, and 1:10,000. Two samples of each dilution were then treated with either a 25%, 50%, or 100% concentration of polyethylene glycol (PEG). Fusion was found in the 1:100 dilution sample treated with the 100% PEG concentration. The rest of the samples appeared to have been destroyed. Two further replications were inconclusive as the platelets did not survive the isolation process. Any future attempts were canceled due to the shutdowns related to the COVID-19 pandemic. Despite inconclusive results, the fusion found in the first trial is encouraging that future research might find a method to consistently obtain platelet fusion

An Abstract Interpretation for ML Equality Kinds

The definition of Standard ML provides a form of generic equality which is inferred for certain types, called equality types, on which it is possible to define an equality relation in ML. However, the standard definition is incomplete in the sense that there are interesting and useful types which are not inferred to be equality types but for which an equality relation can be defined in ML in a uniform manner. In this paper, a refinement of the Standard ML system of equality types is introduced and is proven sound and complete with respect to the existence of a definable equality. The technique used here is based on an abstract interpretation of ML operators as monotone functions over a three point lattice. It is shown how the equality relation can be defined (as an ML program) from the definition of a type with our equality property. Finally, a sound, efficient algorithm for inferring the equality property which corrects the limitations of the standard definition in all cases of practical interest is demonstrated

The mathematical description of the electrosynthesis of composites of oxy-hydroxycompounds cobalt with polypyrrole overooxidazed

The electrosynthesis of the composite with of the overoxidized polypyrrole with cobalt oxy-hydroxide in strongly acidic media has been described mathematically, using linear stability theory and bifurcation analysis. The steadystates stability conditions and oscillatory and monotonic instability requirements have been described too. The system´s behavior was compared with behavior of other systems with overoxidation, electropolymerization of heterocyclic compounds and electrosynthesis of the cobalt oxy-hydroxides

Feasibility of a Brief Community-Based Train-the-Trainer Lesson to Reduce the Risk of Falls Among Community Dwelling Older Adults

The Better Balance, Better Bones, Better Bodies (B-Better©) program was developed to disseminate simple home-based strategies to prevent falls and improve functional health of older adults using a train-the-trainer model. Delivered by Family & Community Education Study Group program volunteers, the lesson stresses the importance of a physically active lifestyle to optimal health and promotes best practice strategies to prevent falls. Data from 235 program participants show participants gained knowledge and learned to reduce their risk of falls during this one-hour brief encounter. Over 80% reported intent to change behavior related to physical activity and to perform home safety checks

Let's face the music: A behavioral and electrophysiological exploration of score reading

This experiment was carried out to determine whether reading diatonic violations in a musical score elicits similar endogenous ERP components when hearing such violations in the auditory modality. In the behavioral study, musicians were visually presented with 120 scores of familiar musical pieces, half of which contained a diatonic violation. The score was presented in a measure-by-measure manner. Self-paced reading was significantly delayed for measures containing a violation, indicating that sight reading a violation requires additional effort. In the ERP study, the musical phrases were presented in a “RSVP”-like manner. We predicted that diatonic violations would elicit a late positive component. However, the ERP associated with the measure where a violation was presented showed a negativity instead. The negativity started around 100 ms and lasted for the entire recording period. This long-lasting negativity encompassed at least three distinct effects that were possibly related to violation detection, working memory processing, and a further integration/interpretation process

Subcellular Localization of the Leucine Biosynthetic Enzymes in Yeast

When baker's yeast spheroplasts were lysed by mild osmotic shock, practically all of the isopropylmalate isomerase and the β-isopropylmalate dehydrogenase was released into the 30,000 × g supernatant fraction, as was the cytosol marker enzyme, glucose-6-phosphate dehydrogenase. α-Isopropylmalate synthase, however, was not detected in the initial supernatant, but could be progressively solubilized by homogenization, appearing more slowly than citrate synthase but faster than cytochrome oxidase. Of the total glutamate-α-ketoisocaproate transaminase activity, approximately 20% was in the initial soluble fraction, whereas solubilization of the remainder again required homogenization of the spheroplast lysate. Results from sucrose density gradient centrifugation of a cell-free particulate fraction and comparison with marker enzymes suggested that α-isopropylmalate synthase was located in the mitochondria. It thus appears that, in yeast, the first specific enzyme in the leucine biosynthetic pathway (α-isopropylmalate synthase) is particulate, whereas the next two enzymes in the pathway (isopropylmalate isomerase and β-isopropylmalate dehydrogenase) are “soluble,” with glutamate-α-ketoisocaproate transaminase activity being located in both the cytosol and particulate cell fractions

Estimating adaptive cruise control model parameters from on-board radar units

Two new methods are presented for estimating car-following model parameters using data collected from the Adaptive Cruise Control (ACC) enabled vehicles. The vehicle is assumed to follow a constant time headway relative velocity model in which the parameters are unknown and to be determined. The first technique is a batch method that uses a least-squares approach to estimate the parameters from time series data of the vehicle speed, space gap, and relative velocity of a lead vehicle. The second method is an online approach that uses a particle filter to simultaneously estimate both the state of the system and the model parameters. Numerical experiments demonstrate the accuracy and computational performance of the methods relative to a commonly used simulation-based optimization approach. The methods are also assessed on empirical data collected from a 2019 model year ACC vehicle driven in a highway environment. Speed, space gap, and relative velocity data are recorded directly from the factory-installed radar unit via the vehicle's CAN bus. All three methods return similar mean absolute error values in speed and spacing compared to the recorded data. The least-squares method has the fastest run-time performance, and is up to 3 orders of magnitude faster than other methods. The particle filter is faster than real-time, and therefore is suitable in streaming applications in which the datasets can grow arbitrarily large.Comment: Accepted for poster presentation at the Transportation Research Board 2020 Annual Meeting, Washington D.

Physical Activity in Childhood May Be the Key to Optimizing Lifespan Skeletal Health

Physical activities undertaken in childhood, particularly activities which apply large forces quickly convey optimal benefits to bone mass, size, and structure. Evidence is accumulating that benefits persist well beyond activity cessation. This review examines the potential for early childhood activity to improve bone mineralization and structure and explores childhood activity as prevention for osteoporosis in later life