1,167 research outputs found
VGOS VLBI Intensives between MACGO12M and WETTZ13S for the rapid determination of UT1-UTC
In this work, we present a status update and results of the designated
research and development VLBI Intensive program VGOS-INT-S, observed between
MACGO12M and WETTZ13S for the rapid determination of the Earth's phase of
rotation, expressed via UT1-UTC. The main novelty of these sessions is the use
of a special observation strategy, rapidly alternating between high- and
low-elevation scans, enabling an improved determination of delays caused by the
neutral atmosphere. Since 2021, 25 Intensive sessions have been observed
successfully. In early 2022, VGOS-INT-S was among the most accurate Intensive
programs with an average formal error of 3.1 s and a
bias w.r.t. IERS C04 of 1.1 s. Later, the session performance decreased
due to multiple technical difficulties.Comment: 8 pages, 5 figure
Assessing the ecological vulnerability of the shallow steppe Lake Neusiedl (Austria-Hungary) to climate-driven hydrological changes using a palaeolimnological approach
9openInternationalBothLake Neusiedl, the largest steppe lake in Europe, is particularly sensitive to climate variations due to its extreme shallowness (zmax = 1.8 m) and low ratio of catchment to lake area (3.5 : 1). Changes in water budget, salinity and turbidity have key implications for the lakeās ecology and management. Here, we present a multi-proxy palaeolimnological reconstruction of the evolution of Lake Neusiedl since the end of its last complete desiccation (1865ā1868), based on an undisturbed radiometrically dated core taken from the open water portion of the lake. Geochemical and biological (algal) proxies outline the succession of three major ecological stages since 1873 Ā± 16 yrs, with the first major changes appearing already in the 1930s as driven by climate related hydrological variability. Subfossil diatoms proved to be reliable for tracking long-term changes in the trophic conditions of Lake Neusiedl while diatom-inferred lake conductivity revealed to be unreliable due to a combination of lake environmental settings and the absence of a site-specific training set. Nonetheless, multivariate statistical analyses and comparisons with limnological data confirm a great potential of subfossil diatoms for revealing past ecological changes and tipping points of shallow lakes, as long as studies rely on a multi-proxy approach. In agreement with limnological surveys, the sediment record corroborates the high vulnerability of Lake Neusiedl, both in present and past times, towards climate-driven changes in water level and salinity, and allows the prediction, by analogy with the past, of future ecological changes in a context of global warming and increasing nutrient inputs from non-point sources.openTolotti, M.; Guella, G.; Herzig, A.; Rodeghiero, M.; Rose, N.L.; Soja, G.; Zechmeister, T.; Yang, H.; Teubner, K.Tolotti, M.; Guella, G.; Herzig, A.; Rodeghiero, M.; Rose, N.L.; Soja, G.; Zechmeister, T.; Yang, H.; Teubner, K
Quantifying black carbon deposition over the Greenland ice sheet from forest fires in Canada
Black carbon (BC) concentrations observed in 22 snowpits sampled in the northwest sector of the Greenland ice sheet in April 2014 have allowed us to identify a strong and widespread BC aerosol deposition event, which was dated to have accumulated in the pits from two snow storms between 27 July and 2 August 2013. This event comprises a significant portion (57% on average across all pits) of total BC deposition over 10 months (July 2013 to April 2014). Here we link this deposition event to forest fires burning in Canada during summer 2013 using modeling and remote sensing tools. Aerosols were detected by both the CloudāAerosol Lidar with Orthogonal Polarization (on board CALIPSO) and Moderate Resolution Imaging Spectroradiometer (Aqua) instruments during transport between Canada and Greenland. We use highāresolution regional chemical transport modeling (WRFāChem) combined with highāresolution fire emissions (FINNv1.5) to study aerosol emissions, transport, and deposition during this event. The model captures the timing of the BC deposition event and shows that fires in Canada were the main source of deposited BC. However, the model underpredicts BC deposition compared to measurements at all sites by a factor of 2ā100. Underprediction of modeled BC deposition originates from uncertainties in fire emissions and model treatment of wet removal of aerosols. Improvements in model descriptions of precipitation scavenging and emissions from wildfires are needed to correctly predict deposition, which is critical for determining the climate impacts of aerosols that originate from fires
Cities in fiction: Perambulations with John Berger
This paper explores selected novels by John Berger in which cities play a central role. These cities are places, partially real and partially imagined, where memory, hope, and despair intersect. My reading of the novels enables me to trace important themes in recent discourses on the nature of contemporary capitalism, including notions of resistance and universality. I also show how Berger?s work points to a writing that can break free from the curious capacity of capitalism to absorb and feed of its critique
Mutual Zonated Interactions of Wnt and Hh Signaling Are Orchestrating the Metabolism of the Adult Liver in Mice and Human
The Hedgehog (Hh) and Wnt/Ī²-Catenin (Wnt) cascades are morphogen pathways whose pronounced influence on adult liver metabolism has been identified in recent years. How both pathways communicate and control liver metabolic functions are largely unknown. Detecting core components of Wnt and Hh signaling and mathematical modeling showed that both pathways in healthy liver act largely complementary to each other in the pericentral (Wnt) and the periportal zone (Hh) and communicate mainly by mutual repression. The Wnt/Hh module inversely controls the spatiotemporal operation of various liver metabolic pathways, as revealed by transcriptome, proteome, and metabolome analyses. Shifting the balance to Wnt (activation) or Hh (inhibition) causes pericentralization and periportalization of liver functions, respectively. Thus, homeostasis of the Wnt/Hh module is essential for maintaining proper liver metabolism and to avoid the development of certain metabolic diseases. With caution due to minor species-specific differences, these conclusions may hold for human liver as well
From a certain point of view: sensory phenomenological envisionings of running space and place
The precise ways in which we go about the mundane, repetitive, social actions of everyday life are central concerns of ethnographers and theorists working within the traditions of the sociology of the mundane and sociological phenomenology. In this article, we utilize insights derived from sociological phenomenology and the newly developing field of sensory sociology to investigate a particular, mundane, and embodied social practice, that of training for distance running in specific places: our favored running routes. For, despite a growing body of ethnographic studies of particular sports, little analytic attention has been devoted to the actual, concrete practices of ādoingā or āproducingā sporting activity, particularly from a sensory ethnographic perspective. Drawing upon data from a 2-year joint autoethnographic research project, here we explore the visual dimension, focusing upon three key themes in relation to our runnersā visualization of, respectively, (1) hazardous places, (2) performance places, (3) the timeāspaceāplace nexus
Citrullinated histone H3, a marker of extracellular trap formation, is increased in blood of stable asthma patients
Background: Emerging data indicates that extracellular traps (ETs), structures formed by various immune cell types,
may contribute to the pathology of noninfectious infammatory diseases. Histone hypercitrullination is an important
step in ETs formation and citrullinated histone H3 (H3cit) is considered a novel and specifc biomarker of that process.
In the present study we have evaluated circulating H3cit in stable asthmatics and investigated its relationship with
asthma severity, pulmonary function and selected blood and bronchoalveolar lavage (BAL) biomarkers.
Methods: In 60 white adult stable asthmatics and 50 well-matched controls we measured serum levels of H3cit. In
asthmatics we also performed bronchoscopy with BAL. We analyzed blood and BAL biomarkers, including interleukin
(IL)-4, IL-5, IL-6, IL-10, IL-12p70, IL-17A and interferon Ī³. For statistical analysis, Mann-Whitney U-test, Ļ2
test, one-way
ANCOVA, ROC curve analysis and univariate linear regression were applied. Independent determinants of H3cit were
established in a multiple linear regression model.
Results: Asthma was characterized by elevated circulating H3cit (17.49 [11.25ā22.58] vs. 13.66 [8.66ā18.87] ng/ml,
p=0.03). In asthmatics positive associations were demonstrated between serum H3cit and lung function variables,
including total lung capacity (TLC) (Ī²=0.37 [95% CI 0.24-0.50]) and residual volume (Ī²=0.38 [95% CI 0.25ā0.51]).
H3cit was increased in asthma patients receiving systemic steroids (p=0.02), as well as in subjects with BAL eosinoā
philia above 144 cells/ml (p=0.02). In asthmatics, but not in controls, circulating H3cit correlated well with number
of neutrophils (Ī²=0.31 [95% CI 0.19ā0.44]) and monocytes (Ī²=0.42 [95% CI 0.29ā0.55]) in peripheral blood. Furtherā
more, BAL macrophages, BAL neutrophils, TLC, high-sensitivity C-reactive protein, Il-12p70 and bronchial obstruction
degree were independent determinants of H3cit in a multivariate linear regression model.
Conclusions: Asthma is characterized by increased circulating H3cit likely related to the enhanced lung ETs formaā
tion. Inhibition of ETs might be a therapeutic option in selected asthma phenotypes, such as neutrophilic asthma
Chemical data assimilation estimates of continental U.S. ozone and nitrogen budgets during the Intercontinental Chemical Transport Experiment-North America
Global ozone analyses, based on assimilation of stratospheric profile and ozone column measurements, and NOy predictions from the Real-time Air Quality Modeling System (RAQMS) are used to estimate the ozone and NOy budget over the continental United States during the July-August 2004 Intercontinental Chemical Transport Experiment-North America (INTEX-A). Comparison with aircraft, satellite, surface, and ozonesonde measurements collected during INTEX-A show that RAQMS captures the main features of the global and continental U.S. distribution of tropospheric ozone, carbon monoxide, and NOy with reasonable fidelity. Assimilation of stratospheric profile and column ozone measurements is shown to have a positive impact on the RAQMS upper tropospheric/lower stratosphere ozone analyses, particularly during the period when SAGE III limb scattering measurements were available. Eulerian ozone and NOy budgets during INTEX-A show that the majority of the continental U.S. export occurs in the upper troposphere/lower stratosphere poleward of the tropopause break, a consequence of convergence of tropospheric and stratospheric air in this region. Continental U.S. photochemically produced ozone was found to be a minor component of the total ozone export, which was dominated by stratospheric ozone during INTEX-A. The unusually low photochemical ozone export is attributed to anomalously cold surface temperatures during the latter half of the INTEX-A mission, which resulted in net ozone loss during the first 2 weeks of August. Eulerian NOy budgets are shown to be very consistent with previously published estimates. The NOy export efficiency was estimated to be 24%, with NOx + PAN accounting for 54% of the total NOy export during INTEX-A. Copyright 2007 by the American Geophysical Union
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