92 research outputs found
Direct numerical simulation of quasi-two-dimensional MHD turbulent shear flows
Direct numerical simulations (DNS) are performed to study the turbulent shear
flow of an electrically conducting fluid in a cylindrical container. The flow
is driven by the interaction between the radial electric currents ()
injected through a large number of small electrodes at the bottom wall and an
axial magnetic field. All the numerical parameters, including the geometry of
the container, the total injcected currents and the magnetic field, are in line
with the experiment performed in J. Fluid Mech. 456, 137-159. First, witth
laminar Hartmann layers, three dimensional simulations recover experimentally
measured quantities (global angular momentum, velocity profiles). The variation
laws for the wall shear stresses, the energy spectra and visualizations of flow
structures near the side wall highlight separation and turbulence within the
side wall layers. Furthermore, a parametric analysis of the flow reveals that
Ekman recirculations have significant influence on the vortex size, the free
shear layer, and the global dissipation. Second, we recover the scaling laws of
the cutoff scale that separate the large quasi-two-dimensional scales from the
small three-dimensional ones (J. Fluid Mech. 118, 507-518), and thus establish
their validity in sheared MHD turbulence. Furthermore, we find that
three-componentality are and the three-dimensionality appear concurrently and
that both the two-dimensional cutoff frequency and the mean energy associated
to the axial component of velocity scale with , respectively as
and
Hepatitis and Encephalitis due to Coxsackie Virus A9 in an Adult
Coxsackie virus infection most commonly manifests itself in the neonatal period as a multisystem disease. This life-threatening neonatal infection has been recently treated with a new anti-picornaviral drug, pleconaril. In contrast, in adults Coxsackie virus is an uncommon source of hepatitis, but Coxsackie virus type B has been described in case reports to cause hepatitis. This is the first case report of hepatitis and encephalitis secondary to Coxsackie virus type A9 in an adult. This virus was found in a culture of the cerebrospinal fluid and was confirmed by PCR. The patient recovered completely without specific treatment
Functional characterization of infiltrating T lymphocytes in human hepatic allografts
We have employed recently developed techniques in T-cell culturing to study the nature and function of infiltrating hepatic allograft T cells. Using the rationale that intragraft T cells are activated during cell mediated damage to the allograft, we were able to show that these cells would propagate and remain functionally active in the presence of the T-cell growth factor, IL-2. In several instances, phenotyiic analysis of cells grown in this manner was very similar to that found within the graft. Both proliferative and cytotoxic responses could be detected from the cultured cell lines. The majority of the proliferative responses were donor-directed and immunogenetic analysis could define donor-directed HLA reactivity, to either class I or class II antigens, or both. Monoclonal anti-HLA antibodies inhibition profiles verified the apparent HLA reactivity. In a smaller percentage of cases, only IL-2 responsiveness could be detected, and no HLA reactivity could be determined. Cytotoxicity could be detected against both class I and class II antigens, however, those cells which demonstrated a greater magnitude of donor-directed cytotoxicity appeared to be directed against class I antigens. A significant correlation between donor-directed proliferation of biopsy cultured lymphocytes and cellular rejection was found. This model appears to be useful in delineating functions of the intragraft T-cell population during rejection. © 1986
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Dose response of the 16p11.2 distal copy number variant on intracranial volume and basal ganglia.
Carriers of large recurrent copy number variants (CNVs) have a higher risk of developing neurodevelopmental disorders. The 16p11.2 distal CNV predisposes carriers to e.g., autism spectrum disorder and schizophrenia. We compared subcortical brain volumes of 12 16p11.2 distal deletion and 12 duplication carriers to 6882 non-carriers from the large-scale brain Magnetic Resonance Imaging collaboration, ENIGMA-CNV. After stringent CNV calling procedures, and standardized FreeSurfer image analysis, we found negative dose-response associations with copy number on intracranial volume and on regional caudate, pallidum and putamen volumes (ÎČâ=â-0.71 to -1.37; Pâ<â0.0005). In an independent sample, consistent results were obtained, with significant effects in the pallidum (ÎČâ=â-0.95, Pâ=â0.0042). The two data sets combined showed significant negative dose-response for the accumbens, caudate, pallidum, putamen and ICV (Pâ=â0.0032, 8.9âĂâ10-6, 1.7âĂâ10-9, 3.5âĂâ10-12 and 1.0âĂâ10-4, respectively). Full scale IQ was lower in both deletion and duplication carriers compared to non-carriers. This is the first brain MRI study of the impact of the 16p11.2 distal CNV, and we demonstrate a specific effect on subcortical brain structures, suggesting a neuropathological pattern underlying the neurodevelopmental syndromes
Altimetry for the future: Building on 25 years of progress
In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and provides guidance for future mission design, research activities, and sustainable operational radar altimetry data exploitation. Recommendations provided are fundamental for optimizing further scientific and operational advances of oceanographic observations by altimetry, including requirements for spatial and temporal resolution of altimetric measurements, their accuracy and continuity. There are also new challenges and new openings mentioned in the paper that are particularly crucial for observations at higher latitudes, for coastal oceanography, for cryospheric studies and for hydrology. The paper starts with a general introduction followed by a section on Earth System Science including Ocean Dynamics, Sea Level, the Coastal Ocean, Hydrology, the Cryosphere and Polar Oceans and the ââGreenâ Ocean, extending the frontier from biogeochemistry to marine ecology. Applications are described in a subsequent section, which covers Operational Oceanography, Weather, Hurricane Wave and Wind Forecasting, Climate projection. Instrumentsâ development and satellite missionsâ evolutions are described in a fourth section. A fifth section covers the key observations that altimeters provide and their potential complements, from other Earth observation measurements to in situ data. Section 6 identifies the data and methods and provides some accuracy and resolution requirements for the wet tropospheric correction, the orbit and other geodetic requirements, the Mean Sea Surface, Geoid and Mean Dynamic Topography, Calibration and Validation, data accuracy, data access and handling (including the DUACS system). Section 7 brings a transversal view on scales, integration, artificial intelligence, and capacity building (education and training). Section 8 reviews the programmatic issues followed by a conclusion
Mitochondrial physiology
As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery
Mitochondrial physiology
As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery
Altimetry for the future: building on 25 years of progress
In 2018 we celebrated 25âŻyears of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and provides guidance for future mission design, research activities, and sustainable operational radar altimetry data exploitation. Recommendations provided are fundamental for optimizing further scientific and operational advances of oceanographic observations by altimetry, including requirements for spatial and temporal resolution of altimetric measurements, their accuracy and continuity. There are also new challenges and new openings mentioned in the paper that are particularly crucial for observations at higher latitudes, for coastal oceanography, for cryospheric studies and for hydrology.
The paper starts with a general introduction followed by a section on Earth System Science including Ocean Dynamics, Sea Level, the Coastal Ocean, Hydrology, the Cryosphere and Polar Oceans and the âGreenâ Ocean, extending the frontier from biogeochemistry to marine ecology. Applications are described in a subsequent section, which covers Operational Oceanography, Weather, Hurricane Wave and Wind Forecasting, Climate projection. Instrumentsâ development and satellite missionsâ evolutions are described in a fourth section. A fifth section covers the key observations that altimeters provide and their potential complements, from other Earth observation measurements to in situ data. Section 6 identifies the data and methods and provides some accuracy and resolution requirements for the wet tropospheric correction, the orbit and other geodetic requirements, the Mean Sea Surface, Geoid and Mean Dynamic Topography, Calibration and Validation, data accuracy, data access and handling (including the DUACS system). Section 7 brings a transversal view on scales, integration, artificial intelligence, and capacity building (education and training). Section 8 reviews the programmatic issues followed by a conclusion
From AG to Fortis.
The development of the insurance industry in Belgium at the start of the nineteenth century cannot be dissociated from the fundamental social and economic changes which were then taking place in the country: the start of the industrial revolution, which went hand in hand with a great financial evolution, and the transition from the class-based state of the Ancien Regime to a 'contractual' state, with the mercantile middle classes holding the power. One of the first insurance companies in the Southern Netherlands, the Maatschappij van Algemene Verzekeringen (General Insurance Company), AG for short, was set up in 1824 by a group of Brussels capitalists led by the banker Jacques Coghen. In this new study Rene Brion and Jean-Louis Moreau examine the growth of the AG group from its inception until today. An important chapter is reserved for the developments of the last ten years, and more specifically for the capital role which AG, now Fortis (B), plays in the project of the 'great Belgian bank', after the takeover and merger of the ASLK and the Generale Bankmaatschappij. From AG to Fortis (1824-1999) deals with the history of the oldest and most important insurance company in Belgium and with it the history of the Belgian insurance industry. With its brilliant and often unexpected illustrations it also gives the reader a picture of the development of demographics, mathematics, medicine, technology and also, of course, economic evolution. Rene Brion and Jean-Louis Moreau are members of the Vereniging voor de Valorisatie van Bedrijfsarchieven (Association for the Assessment of Company Archives) and authors of several studies on economic history and industrial archaeology, including the company monographs of Tractebel, Fabrimetal and the Generale Maatschappij van Belgie
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