4,525 research outputs found
Monitoring panel performance within and between sensory experiments by multi-way analysis
In sensory analysis a panel of trained assessors evaluates a set of samples
according to specific sensory descriptors. The training improves objectivity and
reliability of assessments. However, there can be individual differences between
assessors left after the training that should be taken into account in the analysis.
Monitoring panel performance is then crucial for optimal sensory evaluations. The
quality of the results is strongly dependent on the performance of each assessor and
of the panel as a whole. The present work proposes to analyze the panel performance
within single sensory evaluations and between consecutive evaluations. The
basic idea is to use multi-way models to handle the three-way nature of the sensory
data. Specifically, a PARAFAC model is used to investigate the panel performance
in the single experiment. N-PLS model is used to test the predictive ability of the
panel on each experiment. A PARAFAC model is also used for monitoring panel
performance over different experiments
Localization of NG2 immunoreactive neuroglia cells in the rat locus coeruleus and their plasticity in response to stress
The locus coeruleus (LC) nucleus modulates adaptive behavioural responses to stress and dysregulation of LC neuronal activity is implicated in stress-induced mental illnesses. The LC is composed primarily of noradrenergic neurons together with various glial populations. A neuroglia cell-type largely unexplored within the LC is the NG2 cell. NG2 cells serve primarily as oligodendrocyte precursor cells throughout the brain. However, some NG2 cells are in synaptic contact with neurons suggesting a role in information processing. The aim of this study was to neurochemically and anatomically characterise NG2 cells within the rat LC. Furthermore, since NG2 cells have been shown to proliferate in response to traumatic brain injury, we investigated whether such NG2 cells plasticity also occurs in response to emotive insults such as stress. Immunohistochemistry and confocal microscopy revealed that NG2 cells were enriched within the pontine region occupied by the LC. Close inspection revealed that a sub-population of NG2 cells were located within unique indentations of LC noradrenergic somata and were immunoreactive for the neuronal marker NeuN whilst NG2 cell processes formed close appositions with clusters immunoreactive for the inhibitory synaptic marker proteins gephyrin and the GABA-A receptor alpha3-subunit, on noradrenergic dendrites. In addition, LC NG2 cell processes were decorated with vesicular glutamate transporter 2 immunoreactive puncta. Finally, ten days of repeated restraint stress significantly increased the density of NG2 cells within the LC. The study demonstrates that NG2 IR cells are integral components of the LC cellular network and they exhibit plasticity as a result of emotive challenges
A non-adiabatic approach to entanglement distribution over long distances
Entanglement distribution between trapped-atom quantum memories, viz. single
atoms in optical cavities, is addressed. In most scenarios, the rate of
entanglement distribution depends on the efficiency with which the state of
traveling single photons can be transferred to trapped atoms. This loading
efficiency is analytically studied for two-level, -level, -level,
and double--level atomic configurations by means of a system-reservoir
approach. An off-resonant non-adiabatic approach to loading -level
trapped-atom memories is proposed, and the ensuing trade-offs between the
atom-light coupling rate and input photon bandwidth for achieving a high
loading probability are identified. The non-adiabatic approach allows a broad
class of optical sources to be used, and in some cases it provides a higher
system throughput than what can be achieved by adiabatic loading mechanisms.
The analysis is extended to the case of two double- trapped-atom
memories illuminated by a polarization-entangled biphoton.Comment: 15 pages, 15 figure
HIV infection significantly reduces lipoprotein lipase which remains low after 6 months of antiretroviral therapy
Purpose of the study
Fractional clearance rate of apolipoprotein B100-containing
lipoproteins is reduced in HIV infection before and
after antiretroviral (ARV) treatment [1]. We compared
lipoprotein lipase (LPL) activity and gene expression in
HIV-positive subjects before and 6 months after ARV with
HIV-negative controls.
Methods
Fasting blood post heparin total and hepatic lipase activity,adiponectin, leptin, insulin, glucose, and lipid measurementswere made in 32 HIV-infected and 15 HIVnegative
controls. LPL was estimated by subtractinghepatic lipase from total lipase. Adiponectin, LPL andhormone sensitive lipase (HSL) gene expression weremeasured from iliac crest subcutaneous fat biopsies.Patients were tested before, and 6 months after randomisation to AZT/3TC (n = 15) or TDF/FTC (n = 17) with EFV.Between-group comparison was by Mann-Whitney andpaired samples by the Wilcoxon signed rank tests.
Summary of results
There were no differences in gender, ethnicity, baseline
BMI, regional fat distribution (whole body DEXA) and
visceral (VAT) and subcutaneous fat (SAT) measured by
abdominal CT scans between controls and patients. Trunk
fat/BMI ratio, VAT and VAT:SAT ratio significantly
increased after 6-month ARV therapy (p = 0.01). There
were no differences between groups in serum NEFA,HOMA and leptin levels. Selected other results are shown
in Table 1.
Conclusion
Post heparin lipoprotein lipase activity is reduced in HIV
and does not return to control levels after 6 months of
ARV therapy. AZT-containing regimens are associated
with a greater increase in LPL, LPL gene expression and
plasma adiponectin than TDF
A General Return-Mapping Framework for Fractional Visco-Elasto-Plasticity
We develop a fractional return-mapping framework for power-law
visco-elasto-plasticity. In our approach, the fractional viscoelasticity is
accounted through canonical combinations of Scott-Blair elements to construct a
series of well-known fractional linear viscoelastic models, such as
Kelvin-Voigt, Maxwell, Kelvin-Zener and Poynting-Thomson. We also consider a
fractional quasi-linear version of Fung's model to account for stress/strain
nonlinearity. The fractional viscoelastic models are combined with a fractional
visco-plastic device, coupled with fractional viscoelastic models involving
serial combinations of Scott-Blair elements. We then develop a general
return-mapping procedure, which is fully implicit for linear viscoelastic
models, and semi-implicit for the quasi-linear case. We find that, in the
correction phase, the discrete stress projection and plastic slip have the same
form for all the considered models, although with different property and
time-step dependent projection terms. A series of numerical experiments is
carried out with analytical and reference solutions to demonstrate the
convergence and computational cost of the proposed framework, which is shown to
be at least first-order accurate for general loading conditions. Our numerical
results demonstrate that the developed framework is more flexible, preserves
the numerical accuracy of existing approaches while being more computationally
tractable in the visco-plastic range due to a reduction of in CPU time.
Our formulation is especially suited for emerging applications of fractional
calculus in bio-tissues that present the hallmark of multiple viscoelastic
power-laws coupled with visco-plasticity
Performance Evaluation of Inverted Tee (IT) Bridge System
The Inverted Tee (IT) girder bridge system was originally developed in 1996 by the University of Nebraska–Lincoln (UNL) researchers and Nebraska Department of Transportation (NDOT) engineers. This bridge system currently accounts for over 110 bridges in Nebraska used for both state highways and local county roads. Extensive longitudinal and transverse deck cracking have been observed and noted in numerous bridge inspection reports. Since the IT girder bridge system is relatively new, limited data and knowledge exist on its structural performance and behavior. This study evaluates the IT girder bridge system by conducting twenty field observations as well as recording accelerometer, strain gauge, and LVDT time histories and lidar scans for a selected subset of these bridges and then a three-dimensional finite element analysis (FEA) was conducted. The field observations included visual inspection for damage and developing deck crack maps to identify a trend for the damage. System identification of the bridge deck and girders helped investigate the global and local structural responses, respectively. Operational modal analysis quantified the natural frequencies, damping ratios, and operational deflected shapes for the instrumented IT girder bridges. These results helped diagnose the reason for the longitudinal deck cracking. The IT girders respond non- uniformly for the first operational deflected shape and independently for higher modes. Two comparable bridges, namely one slab and one NU girder bridge, were instrumented to verify and demonstrate that the IT girder behavior is unique. An advanced geospatial analysis was conducted for the IT girder bridges to develop lidar depth maps of the deck and girders elevations. These depth maps help identify locations of potential water/chloride penetration and girders set at various elevations and/or where the deck thickness is non-uniform. Live load tests helped quantify the transverse dynamic behavior of the bridge girders. Quantifying the transverse dynamic behavior helped validate the source of longitudinal deck cracking in IT girder bridges, which was determined to be the differential deflection between adjacent IT girders. The FEA analysis was conducted to evaluate the live load moment and shear distribution factors and compare that to the predicted values calculated from the AASHTO Standard and LRFD bridge design specifications. The comparison indicated that the predicted distribution factors were conservative. Also, interviews with IT bridge producers and contractors were conducted to determine production and construction advantages and challenges of this bridge system
Delayed feedback control of active particles: a controlled journey towards the destination
We explore theoretically the navigation of an active particle based on delayed feedback control. The delayed feedback enters in our expression for the particle orientation which, for an active particle, determines (up to noise) the direction of motion in the next time step. Here we estimate the orientation by comparing the delayed position of the particle with the actual one. This method does not require any real-time monitoring of the particle orientation and may thus be relevant also for controlling sub-micron sized particles, where the imaging process is not easily feasible. We apply the delayed feedback strategy to two experimentally relevant situations, namely, optical trapping and photon nudging. To investigate the performance of our strategy, we calculate the mean arrival time analytically (exploiting a small-delay approximation) and by simulations.DFG, 163436311, SFB 910: Kontrolle selbstorganisierender nichtlinearer Systeme: Theoretische Methoden und AnwendungskonzepteTU Berlin, Open-Access-Mittel - 201
A Reconfigurable Color Reflector by Selective Phase Change of GeTe in a Multilayer Structure
It is shown that a phase change material (PCM), germanium telluride (GeTe), when integrated into a subwavelength layered optical cavity, can produce widely tunable reflective colors. It is shown that the crystallization temperature (Tx) of GeTe is dependent on the film thickness for thin films of less than â 20 nm, which is exploited for color tuning. Four colors from the same physical structure are demonstrated by electrical heating, through novel optical and thermal engineering of a thin film stack that includes two GeTe layers with only a single integrated joule heater element. The selective sensitivity to incident light angle and low polarization dependence, as well as the low static power consumption of this device make it a good candidate for potential consumer electronics applications.A subâ wavelength optical cavity consisting of multiple layers of germanium telluride (GeTe) is shown here to produce widely tunable reflective colors. The dependence of GeTe crystallization temperature on its film thickness is exploited to achieve four colors from the same physical multiâ layer structure. An integrated electrical heating approach is used to switch between different colors.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/148263/1/adom201801214-sup-0001-S1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/148263/2/adom201801214_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/148263/3/adom201801214.pd
Barrier and Sacrificial Protection Mechanisms of Zinc Rich Primers
A specific type of Zinc-Rich Paint was scratched and exposed in salt fog chamber for various exposure times up to 1,000 hours. The corrosion products that developed within the scratched region were studied by optical microscopy, scanning electron microscopy, and Electrochemical Impedance Spectroscopy (EIS). Bode plots were used to obtain the total resistance of the coating by salt spray exposure time. The results suggest that the mechanism of protection of zinc rich paints may not be simply as only sacrificial action followed by only barrier action, but rather an iteration of these two mechanisms exist. Although at very short times, prior to deposition of zinc corrosion products in the scratch, sacrificial action is the only mechanism of protection, once the corrosion products start to form there is a conjunction of the two protection actions with one dominating from time to time. This dual protection mechanism continues until all the available free zinc within the throwing power distance of the scratch has been consumed, at which point only barrier protection remains in action
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