Fluctuation Induced Instabilities in Front Propagation up a Co-Moving Reaction Gradient in Two Dimensions

We study 2D fronts propagating up a co-moving reaction rate gradient in finite number reaction-diffusion systems. We show that in a 2D rectangular channel, planar solutions to the deterministic mean-field equation are stable with respect to deviations from planarity. We argue that planar fronts in the corresponding stochastic system, on the other hand, are unstable if the channel width exceeds a critical value. Furthermore, the velocity of the stochastic fronts is shown to depend on the channel width in a simple and interesting way, in contrast to fronts in the deterministic MFE. Thus, fluctuations alter the behavior of these fronts in an essential way. These affects are shown to be partially captured by introducing a density cutoff in the reaction rate. Some of the predictions of the cutoff mean-field approach are shown to be in quantitative accord with the stochastic results

Research in the field of molecular collision phenomena using molecular beam techniques Final report

Aerodynamic molecular beam interactions with solid surface

Pathological changes within the cerebral vasculature in Alzheimer's disease:New perspectives

Cerebrovascular disease underpins vascular dementia (VaD), but structural and functional changes to the cerebral vasculature contribute to disease pathology and cognitive decline in Alzheimer's disease (AD). In this review, we discuss the contribution of cerebral amyloid angiopathy and non‐amyloid small vessel disease in AD, and the accompanying changes to the density, maintenance and remodelling of vessels (including alterations to the composition and function of the cerebrovascular basement membrane). We consider how abnormalities of the constituent cells of the neurovascular unit – particularly of endothelial cells and pericytes – and impairment of the blood‐brain barrier (BBB) impact on the pathogenesis of AD. We also discuss how changes to the cerebral vasculature are likely to impair Aβ clearance – both intra‐periarteriolar drainage (IPAD) and transport of Aβ peptides across the BBB, and how impaired neurovascular coupling and reduced blood flow in relation to metabolic demand increase amyloidogenic processing of APP and the production of Aβ. We review the vasoactive properties of Aβ peptides themselves, and the probable bi‐directional relationship between vascular dysfunction and Aβ accumulation in AD. Lastly, we discuss recent methodological advances in transcriptomics and imaging that have provided novel insights into vascular changes in AD, and recent advances in assessment of the retina that allow in vivo detection of vascular changes in the early stages of AD

The Frequency of Reevaluation or Peak Flow Meter Documentation in Acute Asthma Exacerbations in the Emergency Department: Are We Treating in Accordance with NIH/NAEPP Guidelines?

Objectives: To evaluate the frequency of peak expiratory flow rate (PEFR) measurement and clinical re-evaluation in the management of ED asthmatic patients. Methods: This was a retrospective chart review examining consecutive asthma patients who presented to the University of California Irvine ED between September 1, 2003 and December 31, 2003. Patients were excluded if they had a diagnosis of COPD, lung cancer, pneumonia, congestive heart failure, alpha 1 anti-trypsin deficiency or were under 5 years of age. Data collected included patient demographics, pulse oximetry reading(s), ED treatments rendered, and frequencies of PEFR measurement (pre and post therapy), of clinical re-evaluations in the ED, and of ED return visits. Results: Of the 122 ED visits from 111 patients, 11 (10%) patients returned during the 4 month study period, with 5 patients (4.5%) returning in less than 72 hours. Seven (6.0%) patients had PEFR done both pre and post treatment and 24 (20%) had one or more PEFR performed either before or after treatment. Only 61 (50%) of the visits had a documented clinical re-evaluation prior to disposition. Conclusions: Despite their documented role in asthma treatment algorithms, PEFR was performed infrequently and clinical re-evaluation was documented in only half of cases. Recommended algorithms for asthma management were not commonly followed in this academic ED

Pattern of Reaction Diffusion Front in Laminar Flows

Autocatalytic reaction between reacted and unreacted species may propagate as solitary waves, namely at a constant front velocity and with a stationary concentration profile, resulting from a balance between molecular diffusion and chemical reaction. The effect of advective flow on the autocatalytic reaction between iodate and arsenous acid in cylindrical tubes and Hele-Shaw cells is analyzed experimentally and numerically using lattice BGK simulations. We do observe the existence of solitary waves with concentration profiles exhibiting a cusp and we delineate the eikonal and mixing regimes recently predicted.Comment: 4 pages, 3 figures. This paper report on experiments and simulations in different geometries which test the theory of Boyd Edwards on flow advection of chemical reaction front which just appears in PRL (PRL Vol 89,104501, sept2002

Best Practices for Data Sharing and Deposit for Librarian Authors

Sharing data is now encouraged by major funding agencies, and many journals require it as a prerequisite for publication. While many of the hard science journals have implemented ‘Data Deposit Requirements’ and ‘Policies’, in the Library Science literature, publishers are beginning to move titles into open access journals, but data deposit requirements are just beginning to be addressed. Librarian authors will increasingly find themselves having to comply with data sharing policies. In this webinar, we look at examples from the Journal of the Medical Library Association and the Journal of eScience Librarianship and discuss best practices in data deposit

On the origin of non-monotonic doping dependence of the in-plane resistivity anisotropy in Ba(Fe1−xTx_{1-x}T_x)2_2As2_2, TT = Co, Ni and Cu

The in-plane resistivity anisotropy has been measured for detwinned single crystals of Ba(Fe$_{1-x}$Ni$_x$)$_2$As$_2$ and Ba(Fe$_{1-x}$Cu$_x$)$_2$As$_2$. The data reveal a non-monotonic doping dependence, similar to previous observations for Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$. Magnetotransport measurements of the parent compound reveal a non-linear Hall coefficient and a strong linear term in the transverse magnetoresistance. Both effects are rapidly suppressed with chemical substitution over a similar compositional range as the onset of the large in-plane resistivity anisotropy. It is suggested that the relatively small in-plane anisotropy of the parent compound in the spin density wave state is due to the presence of an isotropic, high mobility pocket of reconstructed Fermi surface. Progressive suppression of the contribution to the conductivity arising from this isotropic pocket with chemical substitution eventually reveals the underlying in-plane anisotropy associated with the remaining FS pockets.Comment: 12 pages, 9 figure