Reference Quality Upper-Air Measurements: guidance for developing GRUAN data products

The accurate monitoring of climate change imposes strict requirements upon observing systems, in particular regarding measurement accuracy and long-term stability. Currently available data records of the essential climate variables (temperature-T, geopotential-p, humidity-RH, wind, and cloud properties) in the upper-air generally fail to fulfil such requirements. This raises serious issues about the ability to detect, quantify and understand recent climate changes and their causes. GCOS is currently implementing a Reference Upper-Air Network (GRUAN) in order to fill this major void within the global observing system. As part of the GRUAN implementation plan we provide herein fundamental guidelines for establishing and maintaining reference quality atmospheric observations which are based on principal concepts of metrology, in particular traceability. It is argued that the detailed analysis of the uncertainty budget of a measurement technique is the critical step for achieving this goal. As we will demonstrate with an example, detailed knowledge of the calibration procedures and data processing algorithms are required for determining the uncertainty of each individual data point. Of particular importance is the careful assessment of the uncertainties introduced by correction schemes adjusting for systematic effects.

A guide for upper-air reference measurements

The accurate monitoring of climate change imposes strict requirements upon observing systems, in particular regarding measurement accuracy and long-term stability. Currently available data records of the essential climate variables (temperature-T, geopotential-p, humidity-RH, wind, and cloud properties) in the upper-air generally fail to fulfill such requirements. This raises serious issues about the ability to detect, quantify and understand recent climate changes and their causes. GCOS is currently implementing a Reference Upper-Air Network (GRUAN) in order to fill this major void within the global observing system. As part of the GRUAN implementation plan we provide herein fundamental guidelines for establishing and maintaining reference quality atmospheric observations which are based on principal concepts of metrology, in particular traceability. It is argued that the detailed analysis of the uncertainty budget of a measurement technique is the critical step for achieving this goal. As we will demonstrate with an example, detailed knowledge of the calibration procedures and data processing algorithms are required for determining the uncertainty of each individual data point. Of particular importance is the careful assessment of the uncertainties introduced by correction schemes adjusting for systematic effects.

Additive/synergistic efficacy of zoledronic acid and LBH589 in the spheroid-based cellular angiogenesis assay

e14627 Background: The compounds Zoledronic acid (ZA) and LBH589 (histon deactetylase (HDAC) inhibitor) have shown in previous experiments antitumoral and antiangiogenic effects. Aim of this study was to determine their ability to inhibit VEGF-A induced endothelial cell (EC) sprouting and to observe potential additive/synergistic effects of the combination ZA and LBH589 in the spheroid-based cellular 3D angiogenesis assay. Methods: HUVEC spheroids were embedded in a 3D collagen gel, stimulated with VEGF-A [25 ng/ml] and treated for 24h with different concentrations of ZA alone or in combination with LBH589. Sprouting intensity of EC spheroids was quantitated by an image analysis system determining the cumulative sprout length per spheroid using an inverted microscope and digital imaging software. The mean of the cumulative sprout length of 10 randomly selected spheroids was analyzed as an individual data point. Results: Before testing the compounds in combination the single IC50 values for ZA (42 μM) and LBH589 (2.9 μM) were determined. The IC50 of ZA has to be considered with caution because of the low inhibitory effect which did not reach basal sprouting levels. In the first combination experiment a dilution series of ZA was tested in combination with a constant LBH589 concentration [2.9 μM, IC50 value as determined previously]. The combination of ZA with LBH589 was ∼330 fold more effective in the inhibition of EC sprouting than ZA alone [0.58 μM compared to 190 μM]. However, the sprouting intensity in the combination of LBH589 and ZA was very low. Therefore the experiment was repeated with a dilution series of ZA in combination with a constant LBH589 concentration that showed no inhibition of EC sprouting previously (1 μM). The second combination experiment revealed IC50 values of 1300 μM for ZA alone and 1.5 μM in combination with LBH589 [1 μM]. The combination LBH589 and ZA is again ∼870 fold more effective in the inhibition of EC sprouting than ZA alone. Conclusions: Our results indicate a very strong synergistic effect of the combination ZA and LBH589 in the spheroid-based angiogenesis assay. No significant financial relationships to disclose.

Efficiencies of Traditional and Digital Measurement Technologies for Forest Operations

Higher-precision technologies may increase measurement accuracy and efficiency for operational layout while decreasing total planning costs. Although a number of trials have been completed on the potential implementation of some of these new technologies, few have quantified the benefits of such devices in an operational setting. Unit boundaries for 16 (∼1 ac) units were measured by three surveying techniques, comprising (1) a string box, manual compass, and clinometer; (2) a laser, digital compass, and digital data collector; and (3) a GPS. Collected data were compared to a fourth benchmark method established with a total station. Techniques were statistically analyzed and error distributions were developed at either a unit or an individual data-point scale. Time and cost studies were conducted to determine the overall efficiencies of each technique. Our results should assist forest resource managers in their decisions when selecting alternate measurement tools for collecting spatial data. West. J. Appl. For. 20(2):138–143.

Image Compression in Morphometry Studies Requiring 21 CFR Part 11 Compliance: Procedure Is Key with TIFFs and Various JPEG Compression Strengths

This study aims to compare the integrity and reproducibility of measurements created from uncompressed and compressed digital images in order to implement compliance with 21 CFR Part 11 for image analysis studies executed using 21 CFR Part 58 compliant capture systems. Images of a 400-mesh electron microscope grid and H&E stained rat liver tissue were captured on an upright microscope with digital camera using commercially available analysis software. Digital images were stored as either uncompressed TIFFs or in one of five different levels of JPEG compression. The grid images were analyzed with automatic detection of bright objects while the liver images were segmented using color cube-based morphometry techniques, respectively, using commercially-available image analysis software? When comparing the feature-extracted measurements from the TIFF uncompressed to the JPEG compressed images, the data suggest that JPEG compression does not alter the accuracy or reliability to reproduce individual data point measurements in all but the highest compression levels. There is, however, discordance if the initial measure was obtained with a TIFF format and subsequently saved as one of the JPEG levels, suggesting that the use of compression must precede feature extraction. It is a common practice in software packages to work with TIFF uncompressed images. However, this study suggests that the use of JPEG compression as part of the analysis work flow was an acceptable practice for these images and features. Investigators applying image file compression to other organ images will need to validate the utility of image compression in their work flow. A procedure to digitally acquire and JPEG compress images prior to image analysis has the potential to reduce file archiving demands without compromising reproducibility of data.