Eddy Covariance flux errors due to random and systematic timing errors during data acquisition

Modern eddy covariance (EC) systems collect high-frequency data (10–20 Hz) via digital outputs of instru ments. This is an important evolution with respect to the tra ditional and widely used mixed analog/digital systems, as fully digital systems help overcome the traditional limita tions of transmission reliability, data quality, and complete ness of the datasets

Eddy covariance flux errors due to random and systematic timing errors during data acquisition

Modern eddy covariance (EC) systems collect high-frequency data (10–20&thinsp;Hz) via digital outputs of instruments. This is an important evolution with respect to the traditional and widely used mixed analog/digital systems, as fully digital systems help overcome the traditional limitations of transmission reliability, data quality, and completeness of the datasets.However, fully digital acquisition introduces a new problem for guaranteeing data synchronicity when the clocks of the involved devices themselves cannot be synchronized, which is often the case with instruments providing data via serial or Ethernet connectivity in a streaming mode. In this paper, we suggest that, when assembling EC systems in-house, aspects related to timing issues need to be carefully considered to avoid significant flux biases.By means of a simulation study, we found that, in most cases, random timing errors can safely be neglected, as they do not impact fluxes significantly. At the same time, systematic timing errors potentially arising in asynchronous systems can effectively act as filters leading to significant flux underestimations, as large as 10&thinsp;%, by means of attenuation of high-frequency flux contributions. We characterized the transfer function of such filters as a function of the error magnitude and found cutoff frequencies as low as 1&thinsp;Hz, implying that synchronization errors can dominate high-frequency attenuations in open- and enclosed-path EC systems. In most cases, such timing errors neither be detected nor characterized a posteriori. Therefore, it is important to test the ability of traditional and prospective EC data logging systems to assure the required synchronicity and propose a procedure to implement such a test relying on readily available equipment.</p

Exploration Medical System Technical Architecture Overview

The Exploration Medical Capability (ExMC) Element Systems Engineering (SE) goals include defining the technical system needed to support medical capabilities for a Mars exploration mission. A draft medical system architecture was developed based on stakeholder needs, system goals, and system behaviors, as captured in an ExMC concept of operations document and a system model. This talk will discuss a high-level view of the medical system, as part of a larger crew health and performance system, both of which will support crew during Deep Space Transport missions. Other mission components, such as the flight system, ground system, caregiver, and patient, will be discussed as aspects of the context because the medical system will have important interactions with each. Additionally, important interactions with other aspects of the crew health and performance system are anticipated, such as health & wellness, mission task performance support, and environmental protection. This talk will highlight areas in which we are working with other disciplines to understand these interactions

miR-34a Promotes Vascular Smooth Muscle Cell Calcification by Downregulating SIRT1 (Sirtuin 1) and Axl (AXL Receptor Tyrosine Kinase).

Objective- Vascular calcification (VC) is age dependent and a risk factor for cardiovascular and all-cause mortality. VC involves the senescence-induced transdifferentiation of vascular smooth muscle cells (SMCs) toward an osteochondrogenic lineage resulting in arterial wall mineralization. miR-34a increases with age in aortas and induces vascular SMC senescence through the modulation of its target SIRT1 (sirtuin 1). In this study, we aimed to investigate whether miR-34a regulates VC. Approach and Results- We found that miR-34a and Runx2 (Runt-related transcription factor 2) expression correlates in young and old mice. Mir34a &lt;sup&gt;+/+&lt;/sup&gt; and Mir34a &lt;sup&gt;-/-&lt;/sup&gt; mice were treated with vitamin D, and calcium quantification revealed that Mir34a deficiency reduces soft tissue and aorta medial calcification and the upregulation of the VC Sox9 (SRY [sex-determining region Y]-box 9) and Runx2 and the senescence p16 and p21 markers. In this model, miR-34a upregulation was transient and preceded aorta mineralization. Mir34a &lt;sup&gt;-/-&lt;/sup&gt; SMCs were less prone to undergo senescence and under osteogenic conditions deposited less calcium compared with Mir34a &lt;sup&gt;+/+&lt;/sup&gt; cells. Furthermore, unlike in Mir34a &lt;sup&gt;+/+&lt;/sup&gt; SMC, the known VC inhibitors SIRT1 and Axl (AXL receptor tyrosine kinase) were only partially downregulated in calcifying Mir34a &lt;sup&gt;-/-&lt;/sup&gt; SMC. Strikingly, constitutive miR-34a overexpression to senescence-like levels in human aortic SMCs increased calcium deposition and enhanced Axl and SIRT1 decrease during calcification. Notably, we also showed that miR-34a directly decreased Axl expression in human aortic SMC, and restoration of its levels partially rescued miR-34a-dependent growth arrest. Conclusions- miR-34a promotes VC via vascular SMC mineralization by inhibiting cell proliferation and inducing senescence through direct Axl and SIRT1 downregulation, respectively. This miRNA could be a good therapeutic target for the treatment of VC

Optimization of an enclosed gas analyzer sampling system for measuring eddy covariance fluxes of H&lt;sub&gt;2&lt;/sub&gt;O and CO&lt;sub&gt;2&lt;/sub&gt;

Several initiatives are currently emerging to observe the exchange of energy and matter between the earth's surface and atmosphere standardized over larger space and time domains. For example, the National Ecological Observatory Network (NEON) and the Integrated Carbon Observing System (ICOS) are set to provide the ability of unbiased ecological inference across ecoclimatic zones and decades by deploying highly scalable and robust instruments and data processing. In the construction of these observatories, enclosed infrared gas analyzers are widely employed for eddy covariance applications. While these sensors represent a substantial improvement compared to their open- and closed-path predecessors, remaining high-frequency attenuation varies with site properties and gas sampling systems, and requires correction. Here, we show that components of the gas sampling system can substantially contribute to such high-frequency attenuation, but their effects can be significantly reduced by careful system design. From laboratory tests we determine the frequency at which signal attenuation reaches 50 % for individual parts of the gas sampling system. For different models of rain caps and particulate filters, this frequency falls into ranges of 2.5–16.5 Hz for CO2, 2.4–14.3 Hz for H2O, and 8.3–21.8 Hz for CO2, 1.4–19.9 Hz for H2O, respectively. A short and thin stainless steel intake tube was found to not limit frequency response, with 50 % attenuation occurring at frequencies well above 10 Hz for both H2O and CO2. From field tests we found that heating the intake tube and particulate filter continuously with 4 W was effective, and reduced the occurrence of problematic relative humidity levels (RH  &gt; 60 %) by 50 % in the infrared gas analyzer cell. No further improvement of H2O frequency response was found for heating in excess of 4 W. These laboratory and field tests were reconciled using resistor–capacitor theory, and NEON's final gas sampling system was developed on this basis. The design consists of the stainless steel intake tube, a pleated mesh particulate filter and a low-volume rain cap in combination with 4 W of heating and insulation. In comparison to the original design, this reduced the high-frequency attenuation for H2O by  ≈ 3∕4, and the remaining cospectral correction did not exceed 3 %, even at high relative humidity (95 %). The standardized design can be used across a wide range of ecoclimates and site layouts, and maximizes practicability due to minimal flow resistance and maintenance needs. Furthermore, due to minimal high-frequency spectral loss, it supports the routine application of adaptive correction procedures, and enables largely automated data processing across sites

Impact of different eddy covariance sensors, site set-up, and maintenance on the annual balance of CO2 and CH4 in the harsh Arctic environment

Improving year-round data coverage for CO2 and CH4 fluxes in the Arctic is critical for refining the global C budget but continuous measurements are very sparse due to the remote location limiting instrument maintenance, to low power availability, and to extreme weather conditions. The need for tailoring instrumentation, site set up, and maintenance at different sites can add uncertainty to estimates of annual C budgets from different ecosystems. In this study, we investigated the influence of different sensor combinations on fluxes of sensible heat, CO2, latent heat (LE), and CH4, and assessed the differences in annual CO2 and CH4 fluxes estimated with different instrumentation at the same sites. Using data from four sites across the North Slope of Alaska, we found that annual CO2 fluxes estimated with heated (7.5 ± 1.4 gC m−2 yr−1) and non-heated (7.9 ± 1.3 gC m−2 yr−1) anemometers were within uncertainty bounds. Similarly, despite elevated noise in 30-min flux data, we found that summer CO2 fluxes from open (−17.0 ± 1.1 gC m−2 yr−1) and close-path (−14.2 ± 1.7 gC m−2 yr−1) gas analyzers were not significantly different. Annual CH4 fluxes were also within uncertainty bounds when comparing both open (4.5 ± 0.31 gC m−2 yr−1) and closed-path (4.9 ± 0.27 gC m−2 yr−1) gas analyzers as well as heated (3.7 ± 0.26 gC m−2 yr−1) and non-heated (3.7 ± 0.28 gC m−2 yr−1) anemometers. A continuously heated anemometer increased data coverage (64%) relative to non-heated anemometers (47–52%). However, sensible heat fluxes were over-estimated by 12%, on average, with the heated anemometer, contributing to the overestimation of CO2, CH4, and LE fluxes (mean biases of −0.03 μmol m−2 s−1, −0.05 mgC m−2 h−1, and −3.77 W m−2, respectively). To circumvent this potential bias and reduce power consumption, we implemented an intermittent heating strategy whereby activation only occurred when ice or snow blockage of the transducers was detected. This resulted in comparable coverage (50%) during winter to the continuously heated anemometer (46%), while avoiding flux over-estimation. Closed and open-path analyzers showed good agreement, but data coverage was generally greater when using closed-path, especially during winter. Winter data coverage of 26–32% was obtained with closed-path devices, vs 10–14% for the open-path devices with unheated anemometers or up to 46% and 35% using closed and open-path analyzers, respectively with heated anemometers. Accurate estimation of LE remains difficult in the Arctic due to strong attenuation in closed-path systems, even when intake tubes are heated, and due to poor data coverage from open-path sensors in such a harsh environment

Lability of copper bound to humic acid

Geochemical speciation models generally include the assumption that all metal bound to humic acid and fulvic acid (HA, FA) is labile. However, in the current study, we determined the presence of a soluble ‘non-labile’ Cu fraction bound to HA extracted from grassland and peat soils. This was quantified by determining isotopically-exchangeable Cu (E-value) and EDTA-extraction of HA-bound Cu, separated by size-exclusion chromatography (SEC) and assayed by coupled ICP-MS. Evidence of time-dependent Cu fixation by HA was found during the course of an incubation study (160 days); up to 50% of dissolved HA-bound Cu was not isotopically exchangeable. This result was supported by extraction with EDTA where approximately 40% of Cu remained bound to HA despite dissolution in 0.05 M Na2-EDTA. The presence of a substantial non-labile metal fraction held by HA challenges the assumption of wholly reversible equilibrium which is central to current geochemical models of metal binding to humic substances

Рентгенодиагностика хронических заворотов желудка: серия случаев

INTRODUCTION: Volvulus of the stomach is a rare disease that can lead to serious consequences, including death of the patients. Among all volvulus of various parts of the gastrointestinal tract, volvulus of the stomach corresponds to 0.5% of cases.Chronic volvulus, while being detected timely, can be successfully treated conservatively or surgically without leading to life threatening conditions. So the diagnosis of chronic gastric volvulus is an important and topical problem.OBJECTIVE: The aim of the study was the analysis of radiological data of patients with gastric volvulus.MATERIALS AND METHODS: Results of chest, esophagus and stomach X-ray examination of 23 patients with gastric volvulus were analyzed.RESULTS: The results of X-ray examination of 23 patients with gastric volvulus are described. In 9 cases organo-axial volvulus of the stomach was detected, in 12 — mesenteric-axial volvulus, 2 patients had a combined type of inversion. In 3 cases chronic volvulus was combined with total hiatal hernia, in 6 — with gastric tumors, in 9 cases — with perigastritis, in 5 patients volvulus was observed after abdominal surgery.DISCUSSION: In our observations, most patients were diagnosed with chronic volvulus of the stomach along the transverse axis, and longitudinal was less common. We also observed a rare combined gastric volvulus. The development of volvulus in our observations was provoked by perigastritis, gastric tumors, surgical interventions and total hiatal herniaal signs.Complaints of patients and the clinical signs were non-specific, in some cases the disease was asymptomatic. X-ray examination of the esophagus and stomach showed high efficiency in the diagnosis of various types of gastric volvulus.CONCLUSION: X-ray allows to reliably diagnose various types of gastric volvulus. ВВЕДЕНИЕ: Заворот желудка — редкое заболевание, которое может привести к тяжелым последствиям вплоть до летального исхода. Среди всех заворотов различных отделов желудочно-кишечного тракта заворот желудка составляет 0,5%. Вовремя выявленный хронический заворот успешно корригируется консервативным или оперативным путем без угрозы для жизни пациента, поэтому диагностика хронических заворотов желудка является важной и актуальной проблемой.ЦЕЛЬ: Провести анализ возможностей классических рентгеноскопии и рентгенографии в выявлении хронических заворотов желудка.МАТЕРИАЛЫ И МЕТОДЫ: Рентгенологическая картина легких и средостения, пищевода и желудка 23 пациентов с хроническими заворотами желудка.РЕЗУЛЬТАТЫ: Получена рентгенологическая картина состояния желудка 23 пациентов с хроническими заворотами желудка. У 9 пациентов был диагностирован заворот желудка по продольной оси, у 12 пациентов — по поперечной оси, у 2 — комбинированный тип заворота. У 5 пациентов заворот наблюдался после оперативных вмешательств. В 9 случаях заворот сочетался с перигастритом, в 6 — с опухолями желудка, в 3 случаях — с тотальной хиатальной грыжей.ОБСУЖДЕНИЕ: В наших наблюдениях у большинства пациентов диагностирован хронический заворот желудка по поперечной оси, реже встречался заворот по продольной оси. Кроме того, мы наблюдали редкий комбинированный заворот желудка. Развитие заворота в наших наблюдениях провоцировали перигастрит, опухоли желудка, оперативные вмешательства и тотальные грыжи пищеводного отверстия диафрагмы. Жалобы пациентов и клиническая картина носили неспецифический характер, в ряде случаев заболевание протекало бессимптомно. Рентгенологическое исследование пищевода и желудка показало высокую эффективность в диагностике различных видов заворотов желудка.ЗАКЛЮЧЕНИЕ: Рентгеноскопия и рентгенография позволяют диагностировать различные виды хронического заворота желудка

Bidimensional spectroelectrochemistry: application of a new device in the study of a o-vanillin-copper(II) complex

A new bidimensional spectroelectrochemistry setup for UV-Vis absorption measurements has been developed. The new device has been used to follow electrochemical reactions using two different arrangements: 1) a near-normal configuration that supplies information about the processes taking place both on the electrode surface and in the solution adjacent to it, and 2) a long-optical-pathway configuration based on a mobile slit that controls the position of a light beam passing parallel and adjacent to the electrode surface providing information only about the processes taking place in solution during the electrochemical reaction. The new setup has been validated using o-tolidine, a typical reference system for spectroelectrochemistry. The electrochemical mechanism of oxidation/reduction of Cu(o-Va)2(H2O)2 complex (o-Va = o-Vanillin = 2-hydroxy-3-methoxybenzaldehyde) has been studied using bidimensional UV-Vis absorption spectroelectrochemistry. This Cu(II) complex exhibits antimutagenic, anticarcinogenic and superoxide dismutase mimic properties.Junta de Castilla y León (BU033U16), and Ministerio de Economía y Competitividad (CTQ2014-55583-R, CTQ2014-61914-EXP, CTQ2015-71955-REDT)CONICET, UNLP, Junta de Castilla y León (BU033U16), and Ministerio de Economía y Competitividad (CTQ2014-55583-R, CTQ2014-61914-EXP, CTQ2015-71955-REDT