Measuring sub-mm structural displacements using QDaedalus: a digital clip-on measuring system developed for total stations

The monitoring of rigid structures of modal frequencies greater than 5 Hz and sub-mm displacement is mainly based so far on relative quantities from accelerometers, strain gauges etc. Additionally geodetic techniques such as GPS and Robotic Total Stations (RTS) are constrained by their low accuracy (few mm) and their low sampling rates. In this study the application of QDaedalus is presented, which constitutes a measuring system developed at the Geodesy and Geodynamics Lab, ETH Zurich and consists of a small CCD camera and Total Station, for the monitoring of the oscillations of a rigid structure. In collaboration with the Institute of Structural Engineering of ETH Zurich and EMPA, the QDaedalus system was used for monitoring of the sub-mm displacement of a rigid prototype beam and the estimation of its modal frequencies up to 30 Hz. The results of the QDaedalus data analysis were compared to those of accelerometers and proved to hold sufficient accuracy and suitably supplementing the existing monitoring techniques

Noise-assisted classical adiabatic pumping in a symmetric periodic potential

We consider a classical overdamped Brownian particle moving in a symmetric periodic potential. We show that a net particle flow can be produced by adiabatically changing two external periodic potentials with a spatial and a temporal phase difference. The classical pumped current is found to be independent of the friction and to vanish both in the limit of low and high temperature. Below a critical temperature, adiabatic pumping appears to be more efficient than transport due to a constant external force.Comment: six pages, 3 figure

Muonium as a hydrogen analogue in silicon and germanium; quantum effects and hyperfine parameters

We report a first-principles theoretical study of hyperfine interactions, zero-point effects and defect energetics of muonium and hydrogen impurities in silicon and germanium. The spin-polarized density functional method is used, with the crystalline orbitals expanded in all-electron Gaussian basis sets. The behaviour of hydrogen and muonium impurities at both the tetrahedral and bond-centred sites is investigated within a supercell approximation. To describe the zero-point motion of the impurities, a double adiabatic approximation is employed in which the electron, muon/proton and host lattice degrees of freedom are decoupled. Within this approximation the relaxation of the atoms of the host lattice may differ for the muon and proton, although in practice the difference is found to be slight. With the inclusion of zero-point motion the tetrahedral site is energetically preferred over the bond-centred site in both silicon and germanium. The hyperfine and superhyperfine parameters, calculated as averages over the motion of the muon, agree reasonably well with the available data from muon spin resonance experiments.Comment: 20 pages, including 9 figures. To appear in Phys. Rev.

Cell morphology governs directional control in swimming bacteria

The ability to rapidly detect and track nutrient gradients is key to the ecological success of motile bacteria in aquatic systems. Consequently, bacteria have evolved a number of chemotactic strategies that consist of sequences of straight runs and reorientations. Theoretically, both phases are affected by fluid drag and Brownian motion, which are themselves governed by cell geometry. Here, we experimentally explore the effect of cell length on control of swimming direction. We subjected Escherichia coli to an antibiotic to obtain motile cells of different lengths, and characterized their swimming patterns in a homogeneous medium. As cells elongated, angles between runs became smaller, forcing a change from a run-and-tumble to a run-and-stop/reverse pattern. Our results show that changes in the motility pattern of microorganisms can be induced by simple morphological variation, and raise the possibility that changes in swimming pattern may be triggered by both morphological plasticity and selection on morphology

The Relationship of Hypertension in the Elderly to AD, Vascular Dementia, and Cognitive Function

Background: Hypertension at the age of 45 to 50 years may predispose to AD later in life. It is not known whether hypertension after age 65 years also contributes to AD risk, and its effect on cognitive function is also not fully understood. Methods: Data were analyzed from 1,259 Medicare recipients free of dementia in a longitudinal study covering a 7-year period (1991 to 1998). The effect of hypertension was first examined in relationship to the risk for incident AD and then to incident vascular dementia (VaD) using Cox proportional hazards models. Changes in performance over time on tasks of memory, language, and visuospatial/cognitive function were compared in those with and without hypertension using generalized estimating equations. Results: Of the 1,259 subjects, 731 (58.1%) had a history of hypertension associated with diabetes, stroke, and heart disease. A history of hypertension was not associated with an increased risk for AD (rate ratio [RR] 0.9, 95% CI 0.7 to 1.3) but was associated with an increased risk for VaD (1.8 [1.0 to 3.2]). Hypertension was not associated with changes in memory, language, and general cognitive function in normal individuals over time. Compared with individuals with neither hypertension nor heart disease, those with hypertension or heart disease alone had no increase in risk for VaD. However, when both were present, there was a threefold increase in risk for VaD. A sixfold increase in risk was observed when both hypertension and diabetes were present. Conclusions: Hypertension after age 65 years is not associated with AD and does not adversely affect memory, language, or general cognitive function. A history of hypertension may be an antecedent to VaD, particularly in the presence of heart disease or diabetes

SerpinA3N is a novel hypothalamic gene upregulated by a high-fat diet and leptin in mice

Background: Energy homeostasis is regulated by the hypothalamus but fails when animals are fed a high-fat diet (HFD), and leptin insensitivity and obesity develops. To elucidate the possible mechanisms underlying these effects, a microarray-based transcriptomics approach was used to identify novel genes regulated by HFD and leptin in the mouse hypothalamus. Results: Mouse global array data identified serpinA3N as a novel gene highly upregulated by both a HFD and leptin challenge. In situ hybridisation showed serpinA3N expression upregulation by HFD and leptin in all major hypothalamic nuclei in agreement with transcriptomic gene expression data. Immunohistochemistry and studies in the hypothalamic clonal neuronal cell line, mHypoE-N42 (N42), confirmed that alpha 1-antichymotrypsin (α1AC), the protein encoded by serpinA3, is localised to neurons and revealed that it is secreted into the media. SerpinA3N expression in N42 neurons is upregulated by palmitic acid and by leptin, together with IL-6 and TNFα, and all three genes are downregulated by the anti-inflammatory monounsaturated fat, oleic acid. Additionally, palmitate upregulation of serpinA3 in N42 neurons is blocked by the NFκB inhibitor, BAY11, and the upregulation of serpinA3N expression in the hypothalamus by HFD is blunted in IL-1 receptor 1 knockout (IL-1R1−/−) mice. Conclusions: These data demonstrate that serpinA3 expression is implicated in nutritionally mediated hypothalamic inflammation

MANAGING COMMON NIGHTHAWKS AT MCCONNELL AIR FORCE BASE, KANSAS, TO REDUCE AIRCRAFT STRIKES

McConnell Air Force Base (AFB) experiences a unique bird/aircraft hazard problem with migrating common nighthawks from August to October. Nighthawks are the most commonly struck species at McConnell AFB, representing about 38% of reported bird/aircraft strikes. During August and September, nighthawks represented 82% of the bird strikes found on the airfield. Approaches for managing nighthawks on and around airfields are limited because of the night environment, logistics and an incomplete understanding of nighthawk behavior. We determined the number of nighthawks using McConnell AFB and associated foraging, loafing and roosting areas, analyzed their food habits, and developed a translocation management strategy to reduce hazards to aircraft. During 1998, 1999 and 2000, we observed 600, 540 and 920 nighthawks, respectively, on the airfield. The greatest activity on the airfield occurred from September 27-30 in 1998, September 9- 14 in 1999, and September 6-8 in 2000. The peak number of nighthawks observed using the airfield during these periods was 142, 90 and 118, respectively. Nighthawks foraged around the airfield mainly between 1800 and 2200 and usually roosted on the airfield about 1800 with a peak between 2200 and 0200. During one 2-hour survey period in 1999 and 2000, 37 and 59 nighthawks, respectively, were flushed from the airfield. Thirty-seven nighthawks collected during the study consumed mostly corn earworm moths (Noctuidae) and beetles (Scarabaeidae). Management of nighthawks on McConnell AFB has been difficult because commonly used hazing techniques seem to be ineffective; these birds usually return to the same roosting location after being flushed, which can present an even greater risk to aircraft. We developed and evaluated a unique technique for capturing and translocating nighthawks from the airfield. Only 1 of 214 nighthawks translocated 88 km from McConnell AFB returned. Nighthawk/aircraft strikes at McConnell AFB declined from 9 in 1998, when no translocation was conducted, to 0 in 1999 and 3 in 2000

MANAGING COMMON NIGHTHAWKS AT MCCONNELL AIR FORCE BASE, KANSAS, TO REDUCE AIRCRAFT STRIKES

McConnell Air Force Base (AFB) experiences a unique bird/aircraft hazard problem with migrating common nighthawks from August to October. Nighthawks are the most commonly struck species at McConnell AFB, representing about 38% of reported bird/aircraft strikes. During August and September, nighthawks represented 82% of the bird strikes found on the airfield. Approaches for managing nighthawks on and around airfields are limited because of the night environment, logistics and an incomplete understanding of nighthawk behavior. We determined the number of nighthawks using McConnell AFB and associated foraging, loafing and roosting areas, analyzed their food habits, and developed a translocation management strategy to reduce hazards to aircraft. During 1998, 1999 and 2000, we observed 600, 540 and 920 nighthawks, respectively, on the airfield. The greatest activity on the airfield occurred from September 27-30 in 1998, September 9- 14 in 1999, and September 6-8 in 2000. The peak number of nighthawks observed using the airfield during these periods was 142, 90 and 118, respectively. Nighthawks foraged around the airfield mainly between 1800 and 2200 and usually roosted on the airfield about 1800 with a peak between 2200 and 0200. During one 2-hour survey period in 1999 and 2000, 37 and 59 nighthawks, respectively, were flushed from the airfield. Thirty-seven nighthawks collected during the study consumed mostly corn earworm moths (Noctuidae) and beetles (Scarabaeidae). Management of nighthawks on McConnell AFB has been difficult because commonly used hazing techniques seem to be ineffective; these birds usually return to the same roosting location after being flushed, which can present an even greater risk to aircraft. We developed and evaluated a unique technique for capturing and translocating nighthawks from the airfield. Only 1 of 214 nighthawks translocated 88 km from McConnell AFB returned. Nighthawk/aircraft strikes at McConnell AFB declined from 9 in 1998, when no translocation was conducted, to 0 in 1999 and 3 in 2000

High "Normal" blood glucose is associated with decreased brain volume and cognitive performance in the 60s: the PATH through Life Study

Context:Type 2 diabetes is associated with cerebral atrophy, cognitive impairment and dementia. We recently showed higher glucose levels in the normal range not to be free of adverse effects and to be associated with greater hippocampal and amygdalar atrophy in older community-dwelling individuals free of diabetes.Objective:This study aimed to determine whether blood glucose levels in the normal range