Gap-filling strategies for annual VOC flux data sets

Up to now the limited knowledge about the exchange of volatile organic compounds (VOCs) between the biosphere and the atmosphere is one of the factors which hinders more accurate climate predictions. Complete long-term flux data sets of several VOCs to quantify the annual exchange and validate recent VOC models are basically not available. In combination with long-term VOC flux measurements the application of gap-filling routines is inevitable in order to replace missing data and make an important step towards a better understanding of the VOC ecosystem–atmosphere exchange on longer timescales. <br><br> We performed VOC flux measurements above a mountain meadow in Austria during two complete growing seasons (from snowmelt in spring to snow reestablishment in late autumn) and used this data set to test the performance of four different gap-filling routines, mean diurnal variation (MDV), mean gliding window (MGW), look-up tables (LUT) and linear interpolation (LIP), in terms of their ability to replace missing flux data in order to obtain reliable VOC sums. According to our findings the MDV routine was outstanding with regard to the minimization of the gap-filling error for both years and all quantified VOCs. The other gap-filling routines, which performed gap-filling on 24 h average values, introduced considerably larger uncertainties. The error which was introduced by the application of the different filling routines increased linearly with the number of data gaps. Although average VOC fluxes measured during the winter period (complete snow coverage) were close to zero, these were highly variable and the filling of the winter period resulted in considerably higher uncertainties compared to the application of gap-filling during the measurement period. <br><br> The annual patterns of the overall cumulative fluxes for the quantified VOCs showed a completely different behaviour in 2009, which was an exceptional year due to the occurrence of a severe hailstorm, compared to 2011. Methanol was the compound which, at 381.5 mg C m^&minus;2 and 449.9 mg C m^&minus;2, contributed most to the cumulative VOC carbon emissions in 2009 and 2011, respectively. In contrast to methanol emissions, however, considerable amounts of monoterpenes (−327.3 mg C m^&minus;2) were deposited onto the mountain meadow during 2009 caused by a hailstorm. Other quantified VOCs had considerably lower influences on the annual patterns

Improving the representational strategies of children in a music-listening and playing task: an intervention-based study.

This intervention-based study focuses on the relation between music and its graphic representation from a meta-representational point of view. It aims to determine whether middle school students show an increase in meta-representational competence (MRC) after an educational intervention. Three classes of 11 to 14-year-old students participated in the teaching experiment: one experimental class (E) and two control classes (C). An intervention on MRC was carried out on the E class during the hours that were allocated for the regular music lessons, while students from the C classes followed the regular music curriculum. E and C classes were given the same pretest and posttest, which measured students' MRC by means of six representational criteria. One month after the posttest, all classes completed a retention test. The results reveal an overall effect in favour of the E group, despite the negative results for two representational criteria. Moreover, the overall gain, to a great extent, was due to a decrease in the score of the C classes, while the gains in the E class were rather small. Theoretical, methodological and educational implications are discussed

Hidden cusps

International audienceThis paper investigates a situation pointed out in a recent paper, in which a non-singular change of assembly mode of a planar 2-RPR-PR parallel manipulator was realized by encircling a point of multiplicity 4. It is shown that this situation is, in fact, a non-generic one and gives rise to cusps under a small perturbation. Furthermore , we show that, for a large class of singularities of multiplicity 4, there are only two types of stable singularities occurring in a small perturbation: these two types are given by the complex square mapping and the quarto mapping. Incidentally , this paper confirms the fact that, generically, a local non-singular change of solution must be accomplished by encircling a cusp point

Readout of GEM Detectors Using the Medipix2 CMOS Pixel Chip

We have operated a Medipix2 CMOS readout chip, with amplifying, shaping and charge discriminating front-end electronics integrated on the pixel-level, as a highly segmented direct charge collecting anode in a three-stage gas electron multiplier (Triple-GEM) to detect the ionization from $^{55}$Fe X-rays and electrons from $^{106}$Ru. The device allows to perform moderate energy spectroscopy measurements (20 % FWHM at 5.9 keV $X$-rays) using only digital readout and two discriminator thresholds. Being a truly 2D-detector, it allows to observe individual clusters of minimum ionizing charged particles in $Ar/CO_2$ (70:30) and $He/CO_2$ (70:30) mixtures and to achieve excellent spatial resolution for position reconstruction of primary clusters down to $\sim 50 \mu m$, based on the binary centroid determination method.Comment: 18 pages, 14 pictures. submitted to Nuclear Instruments and Methods in Physics Research

Expression of Rb2/p130 in breast and endometrial cancer: correlations with hormone receptor status

Rb2/p130 is a member of the retinoblastoma family of proteins, consisting of Rb, Rb2 and p107, which are important negative regulators of cell cycle progression and differentiation. While Rb2 downregulation was observed in several malignant tumours including endometrial cancer, the role of p130 in breast carcinomas is still unknown. We investigated Rb2 protein expression in tumour tissue from 68 mammary and 41 endometrial carcinomas, 4 mammary cell lines, and normal tissue samples. Therefore, we performed Western blot experiments for Rb2, Rb, and the oestrogen and progesterone receptors (ER, PR-A, PR-B). Weak or absent Rb2 expression was more often found in endometrial (59%) than in mammary carcinomas (24%). We found significant positive correlations of Rb2 expression with Rb, ER, and PR-B in breast cancer samples, and of Rb2 with Rb, PR-A, PR-B, and younger age in endometrial carcinomas. No significant associations with histological grading, stage, nodal involvement, or Ki67 staining were detected. Rb2 mRNA expression was studied by semi-quantitative RT-PCR in 56 endometrial or mammary tissue samples and correlated significantly with Western blot results. Our results indicate that loss of Rb2 expression, mostly by transcriptional down-regulation, may be associated with the development and dedifferentiation of most endometrial and a subset of mammary carcinomas. © 2001 Cancer Research Campaign http://bjcancer.co

The Presampler for the Forward and Rear Calorimeter in the ZEUS Detector

The ZEUS detector at HERA has been supplemented with a presampler detector in front of the forward and rear calorimeters. It consists of a segmented scintillator array read out with wavelength-shifting fibers. We discuss its desi gn, construction and performance. Test beam data obtained with a prototype presampler and the ZEUS prototype calorimeter demonstrate the main function of this detector, i.e. the correction for the energy lost by an electron interacting in inactive material in front of the calorimeter.Comment: 20 pages including 16 figure

Signaling in Secret: Pay-for-Performance and the Incentive and Sorting Effects of Pay Secrecy

Key Findings: Pay secrecy adversely impacts individual task performance because it weakens the perception that an increase in performance will be accompanied by increase in pay; Pay secrecy is associated with a decrease in employee performance and retention in pay-for-performance systems, which measure performance using relative (i.e., peer-ranked) criteria rather than an absolute scale (see Figure 2 on page 5); High performing employees tend to be most sensitive to negative pay-for- performance perceptions; There are many signals embedded within HR policies and practices, which can influence employees’ perception of workplace uncertainty/inequity and impact their performance and turnover intentions; and When pay transparency is impractical, organizations may benefit from introducing partial pay openness to mitigate these effects on employee performance and retention

Strategy Plan A Methodology to Predict the Uniformity of Double-Shell Tank Waste Slurries Based on Mixing Pump Operation

This document presents an analysis of the mechanisms influencing mixing within double-shell slurry tanks. A research program to characterize mixing of slurries within tanks has been proposed. The research program presents a combined experimental and computational approach to produce correlations describing the tank slurry concentration profile (and therefore uniformity) as a function of mixer pump operating conditions. The TEMPEST computer code was used to simulate both a full-scale (prototype) and scaled (model) double-shell waste tank to predict flow patterns resulting from a stationary jet centered in the tank. The simulation results were used to evaluate flow patterns in the tank and to determine whether flow patterns are similar between the full-scale prototype and an existing 1/12-scale model tank. The flow patterns were sufficiently similar to recommend conducting scoping experiments at 1/12-scale. Also, TEMPEST modeled velocity profiles of the near-floor jet were compared to experimental measurements of the near-floor jet with good agreement. Reported values of physical properties of double-shell tank slurries were analyzed to evaluate the range of properties appropriate for conducting scaled experiments. One-twelfth scale scoping experiments are recommended to confirm the prioritization of the dimensionless groups (gravitational settling, Froude, and Reynolds numbers) that affect slurry suspension in the tank. Two of the proposed 1/12-scale test conditions were modeled using the TEMPEST computer code to observe the anticipated flow fields. This information will be used to guide selection of sampling probe locations. Additional computer modeling is being conducted to model a particulate laden, rotating jet centered in the tank. The results of this modeling effort will be compared to the scaled experimental data to quantify the agreement between the code and the 1/12-scale experiment. The scoping experiment results will guide selection of parameters to be varied in the follow-on experiments. Data from the follow-on experiments will be used to develop correlations to describe slurry concentration profile as a function of mixing pump operating conditions. This data will also be used to further evaluate the computer model applications. If the agreement between the experimental data and the code predictions is good, the computer code will be recommended for use to predict slurry uniformity in the tanks under various operating conditions. If the agreement between the code predictions and experimental results is not good, the experimental data correlations will be used to predict slurry uniformity in the tanks within the range of correlation applicability