131 research outputs found
Identifying Advantages and Disadvantages of Variable Rate Irrigation â An Updated Review
Variable rate irrigation (VRI) sprinklers on mechanical move irrigation systems (center pivot or lateral move) have been commercially available since 2004. Although the number of VRI, zone or individual sprinkler, systems adopted to date is lower than expected there is a continued interest to harness this technology, especially when climate variability, regulatory nutrient management, water conservation policies, and declining water for agriculture compound the challenges involved for irrigated crop production. This article reviews the potential advantages and potential disadvantages of VRI technology for moving sprinklers, provides updated examples on such aspects, suggests a protocol for designing and implementing VRI technology and reports on the recent advancements. The advantages of VRI technology are demonstrated in the areas of agronomic improvement, greater economic returns, environmental protection and risk management, while the main drawbacks to VRI technology include the complexity to successfully implement the technology and the lack of evidence that it assures better performance in net profit or water savings. Although advances have been made in VRI technologies, its penetration into the market will continue to depend on tangible and perceived benefits by producers
Pyodine: An open, flexible reduction software for iodine-calibrated precise radial velocities
For existing and future projects dedicated to measuring precise radial
velocities (RVs), we have created an open-source, flexible data reduction
software to extract RVs from \'echelle spectra via the iodine (I)
absorption cell method. The software, called , is completely written
in Python and has been built in a modular structure to allow for easy
adaptation to different instruments. We present the fundamental concepts
employed by , which build on existing I reduction codes, and give
an overview of the software's structure. We adapted to two
instruments, Hertzsprung SONG located at Teide Observatory (SONG hereafter) and
the Hamilton spectrograph at Lick Observatory (Lick hereafter), and demonstrate
the code's flexibility and its performance on spectra from these facilities.
Both for SONG and Lick data, the results generally match the RV
precision achieved by the dedicated instrument pipelines. Notably, our code
reaches a precision of roughly on a short-term solar time
series of SONG spectra, and confirms the planet-induced RV variations of the
star HIP~36616 on spectra from SONG and Lick. Using the solar spectra, we also
demonstrate the capabilities of our software in extracting velocity time series
from single absorption lines. A probable instrumental effect of SONG is still
visible in the RVs, despite being a bit damped as compared to the
original results. With we prove the feasibility of a highly precise,
yet instrument-flexible I reduction software, and in the future the code
will be part of the dedicated data reduction pipelines for the SONG network and
the Waltz telescope project in Heidelberg.Comment: Published in Astronomy & Astrophysics, 13 pages, 8 figure
Spatial Localization of Vitamin D Metabolites in Mouse Kidney by Mass Spectrometry Imaging
Vitamin D plays a key role in the maintenance of calcium/phosphate homeostasis and elicits biological effects that are relevant to immune function and metabolism. It is predominantly formed through UV exposure in the skin by conversion of 7-dehydrocholsterol (vitamin D3). The clinical biomarker, 25-hydroxyvitamin D (25-(OH)-D), is enzymatically generated in the liver with the active hormone 1,25-dihydroxyvitamin D then formed under classical endocrine control in the kidney. Vitamin D metabolites are measured in biomatrices by liquid chromatography-tandem mass spectrometry (LC-MS/MS). In LC-MS/MS, chemical derivatization (CD) approaches have been employed to achieve the desired limit of quantitation. Recently, matrix-assisted laser desorption/ionization (MALDI) has also been reported as an alternative method. However, these quantitative approaches do not offer any spatial information. Mass spectrometry imaging (MSI) has been proven to be a powerful tool to image the spatial distribution of molecules from the surface of biological tissue sections. On-tissue chemical derivatization (OTCD) enables MSI to image molecules with poor ionization efficiently. In this technical report, several derivatization reagents and OTCD methods were evaluated using different MSI ionization techniques. Here, a method for detection and spatial distribution of vitamin D metabolites in murine kidney tissue sections using an OTCD-MALDI-MSI platform is presented. Moreover, the suitability of using the Bruker ImagePrep for OTCD-based platforms has been demonstrated. Importantly, this method opens the door for expanding the range of other poor ionizable molecules that can be studied by OTCD-MSI by adapting existing CD methods
Comprehensive Derivation of a Density Limit of the Evolution of Space
No density can be larger than the Planck density. The time evolution of the actual light horizon should be traced back until the Planck length is reached. However there arises a problem, as in the framework of general relativity theory, GRT, that length is only reached at the density much larger than the Planck density. We investigate the Planck scale, the evolution of space according to the Friedmann Lemaitre equation and the resulting density limit by using EXCEL in a graphic manner. So, we achieve a comprehensive understanding based on our own activity. Additionally, we outline a possible solution of that problem
Comprehensive Derivation of a Density Limit of the Evolution of Space
No density can be larger than the Planck density. The time evolution of the actual light horizon should be traced back until the Planck length is reached. However there arises a problem, as in the framework of general relativity theory, GRT, that length is only reached at the density much larger than the Planck density. We investigate the Planck scale, the evolution of space according to the Friedmann Lemaitre equation and the resulting density limit by using EXCEL in a graphic manner. So, we achieve a comprehensive understanding based on our own activity. Additionally, we outline a possible solution of that problem
New HARPS and FEROS observations of GJ1046
In this paper we present new precise Doppler data of GJ1046 taken between
November 2005 and July 2018 with the HARPS and the FEROS high-resolution
spectographs. In addition, we provide a new stellar mass estimate of GJ1046 and
we update the orbital parameters of the GJ1046 system. These new data and
analysis could be used together with the GAIA epoch astrometry, when available,
for braking the degeneracy and revealing the true mass of the GJ1046
system.Comment: 2 pages, 1 figure, 1 table with RV data (available only in the
Astro-PH version of the paper), Accepted by RNAA
Material efficiency strategies to reducing greenhouse gas emissions associated with buildings, vehicles, and electronics - A review
As one quarter of global energy use serves the production of materials, the more efficient use of these materials presents a significant opportunity for the mitigation of greenhouse gas (GHG) emissions. With the renewed interest of policy makers in the circular economy, material efficiency (ME) strategies such as light-weighting and downsizing of and lifetime extension for products, reuse and recycling of materials, and appropriate material choice are being promoted. Yet, the emissions savings from ME remain poorly understood, owing in part to the multitude of material uses and diversity of circumstances and in part to a lack of analytical effort. We have reviewed emissions reductions from ME strategies applied to buildings, cars, and electronics. We find that there can be a systematic trade-off between material use in the production of buildings, vehicles, and appliances and energy use in their operation, requiring a careful life cycle assessment of ME strategies. We find that the largest potential emission reductions quantified in the literature result from more intensive use of and lifetime extension for buildings and the light-weighting and reduced size of vehicles. Replacing metals and concrete with timber in construction can result in significant GHG benefits, but trade-offs and limitations to the potential supply of timber need to be recognized. Repair and remanufacturing of products can also result in emission reductions, which have been quantified only on a case-by-case basis and are difficult to generalize. The recovery of steel, aluminum, and copper from building demolition waste and the end-of-life vehicles and appliances already results in the recycling of base metals, which achieves significant emission reductions. Higher collection rates, sorting efficiencies, and the alloy-specific sorting of metals to preserve the function of alloying elements while avoiding the contamination of base metals are important steps to further reduce emissions
Hemophagocytic lymphohistiocytosis in critically ill patients: diagnostic reliability of HLH-2004 criteria and HScore
Background: Hemophagocytic lymphohistiocytosis (HLH) is a rare though often fatal hyperinflammatory syndrome mimicking sepsis in the critically ill. Diagnosis relies on the HLH-2004 criteria and HScore, both of which have been developed in pediatric or adult non-critically ill patients, respectively. Therefore, we aimed to determine the sensitivity and specificity of HLH-2004 criteria and HScore in a cohort of adult critically ill patients.
Methods: In this further analysis of a retrospective observational study, patients â„ 18 years admitted to at least one adult ICU at CharitĂ© - UniversitĂ€tsmedizin Berlin between January 2006 and August 2018 with hyperferritinemia of â„ 500 ÎŒg/L were included. Patients' charts were reviewed for clinically diagnosed or suspected HLH. Receiver operating characteristics (ROC) analysis was performed to determine prediction accuracy.
Results: In total, 2623 patients with hyperferritinemia were included, of whom 40 patients had HLH. We found the best prediction accuracy of HLH diagnosis for a cutoff of 4 fulfilled HLH-2004 criteria (95.0% sensitivity and 93.6% specificity) and HScore cutoff of 168 (100% sensitivity and 94.1% specificity). By adjusting HLH-2004 criteria cutoffs of both hyperferritinemia to 3000 Όg/L and fever to 38.2 °C, sensitivity and specificity increased to 97.5% and 96.1%, respectively. Both a higher number of fulfilled HLH-2004 criteria [OR 1.513 (95% CI 1.372-1.667); p < 0.001] and a higher HScore [OR 1.011 (95% CI 1.009-1.013); p < 0.001] were significantly associated with in-hospital mortality.
Conclusions: An HScore cutoff of 168 revealed a sensitivity of 100% and a specificity of 94.1%, thereby providing slightly superior diagnostic accuracy compared to HLH-2004 criteria. Both HLH-2004 criteria and HScore proved to be of good diagnostic accuracy and consequently might be used for HLH diagnosis in critically ill patients.
Clinical trial registration: The study was registered with www.ClinicalTrials.gov (NCT02854943) on August 1, 2016
Disruption of the vacuolar-type H+-ATPase complex in liver causes MTORC1-independent accumulation of autophagic vacuoles and lysosomes
The vacuolar-type H+-translocating ATPase (v-H+-ATPase) has been implicated in the amino aciddependent activation of the mechanistic target of rapamycin complex 1 (MTORC1), an important regulator of macroautophagy. To reveal the mechanistic links between the v-H+-ATPase and MTORC1, we destablilized v-H+-ATPase complexes in mouse liver cells by induced deletion of the essential chaperone ATP6AP2. ATP6AP2-mutants are characterized by massive accumulation of endocytic and autophagic vacuoles in hepatocytes. This cellular phenotype was not caused by a block in endocytic maturation or an impaired acidification. However, the degradation of LC3-II in the knockout hepatocytes appeared to be reduced. When v-H+-ATPase levels were decreased, we observed lysosome association of MTOR and normal signaling of MTORC1 despite an increase in autophagic marker proteins. To better understand why MTORC1 can be active when v-H+-ATPase is depleted, the activation of MTORC1 was analyzed in ATP6AP2-deficient fibroblasts. In these cells, very little amino acid-elicited activation of MTORC1 was observed. In contrast, insulin did induce MTORC1 activation, which still required intracellular amino acid stores. These results suggest that in vivo the regulation of macroautophagy depends not only on v-H+-ATPase-mediated regulation of MTORC1.Peer reviewe
Precise radial velocities of giant stars XV. Mysterious nearly periodic radial velocity variations in the eccentric binary Cygni
Using the Hamilton Echelle Spectrograph at Lick Observatory, we have obtained
precise radial velocities (RVs) of a sample of 373 G- and K-giant stars over
more than 12 years, leading to the discovery of several single and multiple
planetary systems. The RVs of the long-period (~53 years) spectroscopic binary
Cyg (HIP 102488) are found to exhibit additional regular variations
with a much shorter period (~291 days). We intend to improve the orbital
solution of the Cyg system and attempt to identify the cause of the
nearly periodic shorter period variations, which might be due to an additional
substellar companion. We used precise RV measurements of the K-giant star
Cyg from Lick Observatory, in combination with a large set of RVs
collected more recently with the SONG telescope, as well as archival data sets.
Our Keplerian model to the RVs characterizes the orbit of the spectroscopic
binary to higher precision than achieved previously, resulting in a semi-major
axis of , an eccentricity of , and a minimum
mass of the secondary of . Additional short-period RV
variations closely resemble the signal of a Jupiter-mass planet orbiting the
evolved primary component with a period of , but the period and
amplitude of the putative orbit change strongly over time. Furthermore, in our
stability analysis of the system, no stable orbits could be found in a large
region around the best fit. Both of these findings deem a planetary cause of
the RV variations unlikely. Most of the investigated alternative scenarios,
such as an hierarchical triple or stellar spots, also fail to explain the
observed variability convincingly. Due to its very eccentric binary orbit, it
seems possible, however, that Cyg could be an extreme example of a
heartbeat system.Comment: 17 pages, 13 figures, accepted to A&
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