429 research outputs found
Population polygons of tektite specific gravity for various localities in australasia
Comparison of specific gravity of tektites from australia, asia, texas, and czechoslovaki
Does 'relationship intelligence' make big brains in birds?
Lately, Emery et al. developed a bird-specific modification of the âsocial brain hypothesisâ, termed ârelationship intelligence hypothesisâ. Although the idea may be valuable, we doubt that it is supported by sufficient evidence and critically discuss some of the arguments raised by the authors in favour of their new idea
Customization, extension and reuse of outdated hydrogeological software
Each scientist is specialized in his or her field of research and in the tools that he or she uses during the research in a specified site. Thus, he or she is the most suitable person for improving the tools by overcoming their limitations to realize faster and higher quality analysis. However, most scientists are not software developers. Hence, it is necessary to provide them with an easy approach that enables non-software developers to improve and customize their tools. This paper presents an approach for easily improving and customizing any hydrogeological software. It is the result of experiences with updating several interdisciplinary case studies. The main insights of this approachhave been demonstrated using four examples: MIX (FORTRAN-based), BrineMIX (C++-based), EasyQuim and EasyBal (both spreadsheet-based). The improved software has been proven to be a better tool for enhanced analysis by substantially reducing the computation time and the tedious processing of the input and output data files
Geochemical characterisation of northern Norwegian fjord surface sediments: a baseline for further paleo-environmental investigations
Norwegian fjord sediments are promising archives for very high resolution records of past environmental changes. Recent investigations of the modern depositional environment within fjords revealed that the accurate quantification of the inputs, sources, and sedimentary preservation of organic and inorganic material is crucial to decipher long term past climate signals in the sedimentary record of a certain fjord. Here, we investigate the elemental composition, bulk mineral assemblage and grain size distribution of forty-one surface sediment samples from a northern Norwegian fjord system. We reveal modern geochemical and sedimentological processes that occur within the Vestfjord, Ofotfjord and Tysfjord. Our results indicate a very heterogeneous sediment supply and intricate sedimentation processes. We propose that this is related to the complex fjord bathymetry, a low hydrodynamic energy environment, differences in the hinterland bedrock composition and a relatively small drainage area causing a rather diffuse freshwater inflow. Moreover, we show that marine carbonate productivity is the main calcite and Ca source in all three fjords
Exploring the potential for timed cities in Malta : the case of Paola
With ever-increasing interest in the Timed City concept and active mobility-related initiatives that emerged during the COVID-19 pandemic, several cities in the developed Western world have engaged in projects to move towards sustainable mobility. Malta is a car-dependent small Island State with the highest population density in the European Union. Its transport planning policy, leading to ever-increasing car dependency, is having serious detrimental impacts on environmental, social and economic aspects. The archipelagoâs urban environment and demographics provide an ideal context for studying the Timed City concept. This research therefore tests the applicability of the Timed City concept to the Maltese context. A mixed method case study methodology is adopted using GIS and PGIS. Paola, a dense urban locality in Malta of over 9000 inhabitants and spanning 2.5 km2, was chosen. Relevant datasets are mapped out in GIS using ArcGIS Desktop 10.8. Qualitative research to gauge the user perspective using PGIS is ongoing. This paper presents the spatial analysis of the quantitative GIS data and discusses the findings in relation to the current literature. Ultimately, the data indicate undiscovered potential for the Timed City concept to be successfully adapted to such urban contexts, while identifying specific areas requiring improvement and concluding with suggestions for policy intervention and future research.peer-reviewe
Signal-to-noise measurements utilizing a novel dual-energy multimedia detector
Dual-energy measurements are presented utilizing a novel slot-scan digital radiographic imaging detector, operating on gaseous solid state ionization principles. The novel multimedia detector has two basic functional components: a noble gas-filled detector volume operating on gas microstrip principles, and a solid state detector volume. The purpose of this study is to investigate the potential use of this multimedia detector for enhanced dual-energy imaging. The experimental results indicate that the multimedia detector exhibits a large subtracted signal-to-noise ratio. Although the intrinsic merit of this device is being explored for medical imaging, potential applications of the multimedia detector technology in other industrial areas, such as aerospace imaging, aviation security, and surveillance, are also very promising
Pressure Dependence of Born Effective Charges, Dielectric Constant and Lattice Dynamics in SiC
The pressure dependence of the Born effective charge, dielectric constant and
zone-center LO and TO phonons have been determined for -SiC by a linear
response method based on the linearized augmented plane wave calculations
within the local density approximation. The Born effective charges are found to
increase nearly linearly with decreasing volume down to the smallest volume
studied, , corresponding to a pressure of about 0.8 Mbar. This
seems to be in contradiction with the conclusion of the turnover behavior
recently reported by Liu and Vohra [Phys.\ Rev.\ Lett.\ {\bf 72}, 4105 (1994)]
for -SiC. Reanalyzing their procedure to extract the pressure dependence of
the Born effective charges, we suggest that the turnover behavior they obtained
is due to approximations in the assumed pressure dependence of the dielectric
constant , the use of a singular set of experimental data
for the equation of state, and the uncertainty in measured phonon frequencies,
especially at high pressure.Comment: 25 pages, revtex, 5 postscript figures appended, to be published in
Phys. Rev.
The potential of open-access data for flood estimations: uncovering inundation hotspots in Ho Chi Minh City, Vietnam, through a normalized flood severity index
Hydro-numerical models are increasingly important to
determine the adequacy and evaluate the effectiveness of potential flood
protection measures. However, a significant obstacle in setting up
hydro-numerical and associated flood damage models is the tedious and
oftentimes prohibitively costly process of acquiring reliable input data,
which particularly applies to coastal megacities in developing countries and
emerging economies. To help alleviate this problem, this paper explores the
usability and reliability of flood models built on open-access data in
regions where highly resolved (geo)data are either unavailable or difficult
to access yet where knowledge about elements at risk is crucial for
mitigation planning. The example of Ho Chi Minh City, Vietnam, is taken to
describe a comprehensive but generic methodology for obtaining, processing
and applying the required open-access data. The overarching goal of this
study is to produce preliminary flood hazard maps that provide first insights
into potential flooding hotspots demanding closer attention in subsequent,
more detailed risk analyses. As a key novelty, a normalized flood severity
index (INFS), which combines flood depth and duration, is proposed to
deliver key information in a preliminary flood hazard assessment. This index
serves as an indicator that further narrows down the focus to areas where
flood hazard is significant. Our approach is validated by a comparison with
more than 300 flood samples locally observed during three heavy-rain events
in 2010 and 2012 which correspond to INFS-based inundation hotspots in
over 73â% of all cases. These findings corroborate the high potential of
open-access data in hydro-numerical modeling and the robustness of the newly
introduced flood severity index, which may significantly enhance the
interpretation and trustworthiness of risk assessments in the future. The
proposed approach and developed indicators are generic and may be replicated
and adopted in other coastal megacities around the globe.</p
Rapid post-glacial bedrock weathering in coastal Norway
Quantifying bedrock weathering rates under diverse climate conditions is essential to understanding timescales of landscape evolution. Yet, weathering rates are often difficult to constrain, and associating a weathered landform to a specific formative environment can be complicated by overprinting of successive processes and temporally varying climate. In this study, we investigate three sites between 59°N and 69°N along the Norwegian coast that display grussic saprolite, tafoni, and linear weathering grooves on diverse lithologies. These weathering phenomena have been invoked as examples of geomorphic archives predating Quaternary glaciations and consequently as indicators of minimal glacial erosion. Here we apply cosmogenic nuclide chronometry to assess the recent erosional history. Our results demonstrate that all three sites experienced sufficient erosion to remove most cosmogenic nuclides formed prior to the Last Glacial Maximum. This finding is inconsistent with preservation of surficial (<1â2 m) weathered landforms under non-erosive ice during the last glacial period, while simultaneously demonstrating that post-glacial weathering and erosion rates can be locally rapid (4â10 cm kyrâ1) in cold temperate to subarctic coastal locations
Receptor autoantibodies: Associations with cardiac markers, histology, and function in human non-ischaemic heart failure
AIMS: A causal link between non-ischaemic heart failure (HF) and humoral autoimmunity against G-protein-coupled receptors (GPCR) remains unclear except for Chagas' cardiomyopathy. Uncertainty arises from ambiguous reports on incidences of GPCR autoantibodies, spurious correlations of autoantibody levels with disease activity, and lack of standardization and validation of measuring procedures for putatively cardio-pathogenic GPCR autoantibodies. Here, we use validated and certified immune assays presenting native receptors as binding targets. We compared candidate GPCR autoantibody species between HF patients and healthy controls and tested associations of serum autoantibody levels with serological, haemodynamic, metabolic, and functional parameters in HF. METHODS: Ninety-five non-ischaemic HF patients undergoing transcatheter endomyocardial biopsy and 60 healthy controls were included. GPCR autoantibodies were determined in serum by IgG binding to native receptors or a cyclic peptide (for Ă1AR autoantibodies). In patients, cardiac function, volumes, and myocardial structural properties were assessed by cardiac magnetic resonance imaging; right heart catheterization served for determination of cardiac haemodynamics; endomyocardial biopsies were used for histological assessment of cardiomyopathy and determination of cardiac mitochondrial oxidative function by high-resolution respirometry. RESULTS: Autoantibodies against Ă(1) adrenergic (Ă(1) AR), M5-muscarinic (M5AR), and angiotensin II type 2 receptors (AT2R) were increased in HF (all P < 0.001). Autoantibodies against a(1) -adrenergic (a(1) AR) and angiotensin II type 1 receptors (AT1R) were decreased in HF (all P < 0.001). Correlation of alterations of GPCR autoantibodies with markers of cardiac or systemic inflammation or cardiac damage, haemodynamics, myocardial histology, or left ventricular inflammation (judged by T2 mapping) were weak, even when corrected for total IgG. Ă(1) AR autoantibodies were related inversely to markers of left ventricular fibrosis indicated by T1 mapping (r = -0.362, P < 0.05) and global longitudinal strain (r = -0.323, P < 0.05). AT2R autoantibodies were associated with improved myocardial mitochondrial coupling as measured by high-resolution respirometry in myocardial biopsies (r = -0.352, P < 0.05). In insulin-resistant HF patients, AT2R autoantibodies were decreased (r = -.240, P < 0.05), and AT1R autoantibodies were increased (r = 0.212, P < 0.05). CONCLUSIONS: GPCR autoantibodies are markedly altered in HF. However, they are correlated poorly or even inversely to haemodynamic, metabolic, and functional markers of disease severity, myocardial histology, and myocardial mitochondrial efficiency. These observations do not hint towards a specific cardio-pathogenic role of GPCR autoantibodies and suggest that further investigations are required before specific therapies directed at GPCR autoantibodies can be clinically tested in non-ischaemic HF
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