289 research outputs found

    Hilary Putnams Religionsphilosophie zwischen Relativismus und Schizophrenie

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    Ein Jahr vor seiner Konversion zum internen Realismus hat Hilary Putnam 1975 eine Konversion zum expliziten Theismus durchgemacht (vgl. Putnam, H., (1/1992), S. 351) und einer Zeit gewisser Schizophrenie als Gläubiger und Atheist zugleich (vgl. Putnam, H., 1992, S. 1) ein Ende bereitet. Bislang hat nach verbreiteter Meinung Putnam aber weder eine eigene Religionsphilosophie oder auch nur religionsphilosophische Überlegungen systematischer Art im Sinne einer Rechtfertigung der Rationalität religiösen Glaubens derart vorgelegt, als dass klar wäre, was diese Konversion nun in seinem Leben bewirkt hat und folglich, gerade von einem pragmatistischen Standpunkt aus gesehen, mit seiner Philosophie zu tun haben soll. Putnam selbst erachtet seine religiöse Praxis in jüdischer Tradition als einen Katalysator sowohl für seine bereits vor der Konversion einsetzenden ablehnenden Haltung dem Szientismus gegenüber als auch für seinen den Pluralismus anerkennenden internen bzw. pragmatischen Realismus (vgl. Putnam, (1/1992), S. 351). Darüber hinaus fällt es ihm jedoch schwer, einen weiteren Einfluß seiner religiös geprägten Lebensform auf sein philosophisches Denken dingfest zu machen oder gar einen Einfluß seiner Philosophie auf seine religiöse Einstellung

    Melting of subducted slab dictates trace element recycling in global arcs

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    Protracted fluid-induced melting during Barrovian metamorphism in the Central Alps

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    The timing and dynamics of fluid-induced melting in the typical Barrovian sequence of the Central Alps has been investigated using zircon chronology and trace element composition. Multiple zircon domains in leucosomes and country rocks yield U-Pb ages spanning from ∼32 to 22 Ma. The zircon formed during Alpine melting can be distinguished from the inherited and detrital cores on the basis of their age, Th/U (<0.1) and trace element composition. Ti-in-zircon thermometry indicates crystallization temperatures around 620-700°C. Their composition allows discriminating between (1) zircon formation in the presence of early garnet, (2) zircon in equilibrium with abundant L-MREE-rich accessory phases (allanite, titanite and apatite) typical of metatonalites, and (3) zircon formed during melting of metasediments in feldspar-dominated assemblages. The distribution of zircon overgrowths and ages indicate that repeated melting events occurred within a single Barrovian metamorphic cycle at roughly constant temperature; that in the country rocks zircon formation was limited to the initial stages of melting, whereas further melting concentrated in the segregated leucosomes; that melting occurred at different times in samples a few meters apart because of the local rock composition and localized influx of the fluids; and that leucosomes were repeatedly melted when fluids became available. The geochronological data force a revision of the temperature-time path of the migmatite belt in the Central Alps. Protracted melting over 10 My followed the fast exhumation of Alpine eclogites contained within the same region and preceded fast cooling in the order of 100°C/Ma to upper crustal levels

    Congenital dyserythropoietic anemia type I with bone abnormalities, mutations of the CDAN I gene, and significant responsiveness to alpha-interferon therapy

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    Congenital dyserythropoietic anemia type I (CDA I) is a rare autosomal recessive disorder with ineffective erythropoiesis, characteristic morphological abnormalities of erythroblasts, and iron overloading. CDA I is caused by mutations in the CDAN I gene, encoding a protein named codanin-1. Complex bone abnormalities, especially syndactyly, have not been systematically described with this disease. We present two cases of morphologically and genetically confirmed CDA I with striking bone abnormalities and response to treatment with alpha-interferon. Our cases clearly document the association of skeletal anomalism with CDA I and indicate that codanin-1 may play a role in the development of the skeleto

    The responses of the four main substitution mechanisms of H in olivine to H2O activity at 1050 °C and 3 GPa

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    The water solubility in olivine (CH2O) has been investigated at 1050 °C and 3 GPa as a function of water activity (aH2O) at subsolidus conditions in the piston-cylinder apparatus, with aH2O varied using H2O–NaCl fluids. Four sets of experiments were conducted to constrain the effect of aH2O on the four main substitution mechanisms. The experiments were designed to grow olivine in situ and thus achieve global equilibrium (G-type), as opposed to hydroxylating olivine with a pre-existing point-defect structure and impurity content (M-type). Olivine grains from the experiments were analysed with polarised and unpolarised FTIR spectroscopy, and where necessary, the spectra have been deconvoluted to quantify the contribution of each substitution mechanism. Olivine buffered with magnesiowüstite produced absorbance bands at high wavenumbers ranging from 3566 to 3612 cm−1. About 50% of the total absorbance was found parallel to the a-axis, 30% parallel to the b-axis and 20% parallel to the c-axis. The total absorbance and hence water concentration in olivine follows the relationship of CH2O∝aH2O2, indicating that the investigated defect must involve four H atoms substituting for one Si atom (labelled as [Si]). Forsterite buffered with enstatite produced an absorbance band exclusively aligned parallel the c-axis at 3160 cm−1. The band position, polarisation and observed CH2O∝aH2O are consistent with two H substituting for one Mg (labelled as [Mg]). Ti-doped, enstatite-buffered olivine displays absorption bands, and polarisation typical of Ti-clinohumite point defects where two H on the Si-site are charge-balanced by one Ti on a Mg-site (labelled as [Ti]). This is further supported by CH2O∝aH2O and a 1:1 relationship of molar H2O and TiO2 in these experiments. Sc-doped, enstatite-buffered experiments display a main absorption band at 3355 cm−1 with CH2O∝aH2O0.5 and a positive correlation of Sc and H, indicating the coupled substitution of a trivalent cation plus a H for two Mg (labelled as [triv]). Our data demonstrate that extreme care has to be taken when inferences from experiments conducted at aH2O=1 are applied to the mantle, where in most cases, a low aH2O persists. In particular, the higher exponent of the [Si] substitution mechanism means that the contribution of this hydrous defect to total water content will decrease more rapidly with decreasing aH2O than the contributions of the other substitution mechanisms. The experiments confirm previous results that the [Mg] mechanism holds an almost negligible amount of water under nearly all T-P-fO2-fH2O conditions that may be anticipated in nature. However, the small amounts of H2O we find in substituting by this mechanism are similar in the experiments on forsterite doped with either Sc or Ti to those in the undoped forsterite at equivalent aH2O (all buffered by enstatite), confirming the assumption that, thermodynamically, CH2O substituting by each mechanism does not depend on the water concentration that substitutes by other mechanisms.We gratefully acknowledge the Australian Research Council (ARC) support through DP110103134 to JH and HON, and FL130100066 to HON, which partly supported PT during the final stages of this project. RS acknowledges an Australian Postgraduate Award

    A Subsolidus Olivine Water Solubility Equation for the Earth's Upper Mantle

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    The pressure and temperature sensitivity of the two most important point hydrous defects in mantle olivine involving Si vacancies (associated to trace amounts of titanium [TiChu-PD] or exclusively to Si vacancies [Si]) was investigated at subsolidus conditions in a fluid-saturated natural peridotite from 0.5 to 6 GPa (approximately 20–200 km depth) at 750 to 1050°C. Water contents in olivine were monitored in sandwich experiments with a fertile serpentine layer in the middle and olivine and pyroxene sensor layers at the border. Textures and mineral compositions provide evidence that olivine completely recrystallized during the weeklong experiments, whereas pyroxenes displayed only partial equilibration. A site-specific water solubility law for olivine has been formulated based on the experiments reconciling previous contradictory results from low- and high-pressure experiments. The site-specific solubility laws permit to constrain water incorporation into olivine in the subducting slab and the mantle wedge, as these are rare locations on Earth where fluid-present conditions exist. Chlorite dehydration in the hydrated slab is roughly parallel to the isopleth of 50 ± 20 ppm wt H2O in olivine, a value which is independent of the pressure and temperature trajectory followed by the slab. Hydrous defects are dominated by [Si] under the relevant conditions for the mantle wedge affected by fluids coming from the slab dehydration (slab-adjacent low viscosity/seismic low-velocity channel, P > 3 GPa). In cold subduction zones at 5.5 km from the slab surface the storage capacity of the mantle wedge at depths of 100–250 km ranges from 400 to 2,000 ppm wt H2O

    RARE-01: Cerebral infarction in childhood-onset craniopharyngioma patients: results of KRANIOPHARYNGEOM 2007 [Abstract]

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    BACKGROUND: Cerebral infarction (CI) is a known vascular complication following treatment of suprasellar tumors. Risk factors for CI, incidence rate, and long-term prognosis are unknown for patients with childhood-onset craniopharyngioma (CP). METHODS: MRI of 244 CP patients, recruited between 2007 and 2019 in KRANIOPHA-RYNGEOM 2007, were reviewed for CI. Risk factors for CI and outcome after CI were analyzed. RESULTS: Twenty-eight of 244 patients (11%) presented with CI based on reference assessment of MRI. One CI occurred before initial surgery and one case of CI occurred after release of intracystic pressure by a cyst catheter. 26 of 28 CI were detected after surgical tumor resection at a median postoperative interval of one day (range: 0.5 - 53 days). Vascular lesions during surgical procedures were documented in 7 cases with CI. No relevant differences with regard to surgical approaches were found. In all 12 irradiated patients, CI occurred before irradiation. Multivariable analyses showed that hydrocephalus and gross-total resection at the time of primary diagnosis / surgery both were risk factors for CI. After CI, quality of life (PEDQOL) and functional capacity (FMH) were impaired. CONCLUSIONS: CI occurs in 11% of surgically-treated CP cases. Degree of resection and increased intracranial pressure are risk factors, which should be considered in the planning of surgical procedures for prevention of CI

    Flow-dependent regulation of endothelial Tie2 by GATA3 in vivo

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    BACKGROUND Reduced endothelial Tie2 expression occurs in diverse experimental models of critical illness, and experimental Tie2 suppression is sufficient to increase spontaneous vascular permeability. Looking for a common denominator among different critical illnesses that could drive the same Tie2 suppressive (thereby leak inducing) phenotype, we identified "circulatory shock" as a shared feature and postulated a flow-dependency of Tie2 gene expression in a GATA3 dependent manner. Here, we analyzed if this mechanism of flow-regulation of gene expression exists in vivo in the absence of inflammation. RESULTS To experimentally mimic a shock-like situation, we developed a murine model of clonidine-induced hypotension by targeting a reduced mean arterial pressure (MAP) of approximately 50% over 4 h. We found that hypotension-induced reduction of flow in the absence of confounding disease factors (i.e., inflammation, injury, among others) is sufficient to suppress GATA3 and Tie2 transcription. Conditional endothelial-specific GATA3 knockdown (B6-Gata3tm1Jfz^{tm1-Jfz} VE-Cadherin(PAC)-cerERT2) led to baseline Tie2 suppression inducing spontaneous vascular leak. On the contrary, the transient overexpression of GATA3 in the pulmonary endothelium (jet-PEI plasmid delivery platform) was sufficient to increase Tie2 at baseline and completely block its hypotension-induced acute drop. On the functional level, the Tie2 protection by GATA3 overexpression abrogated the development of pulmonary capillary leakage. CONCLUSIONS The data suggest that the GATA3-Tie2 signaling pathway might play a pivotal role in controlling vascular barrier function and that it is affected in diverse critical illnesses with shock as a consequence of a flow-regulated gene response. Targeting this novel mechanism might offer therapeutic opportunities to treat vascular leakage of diverse etiologies

    Search for dark matter in the hidden-photon sector with a large spherical mirror

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    If dark matter consists of hidden-sector photons which kinetically mix with regular photons, a tiny oscillating electric-field component is present wherever we have dark matter. In the surface of conducting materials this induces a small probability to emit single photons almost perpendicular to the surface, with the corresponding photon frequency matching the mass of the hidden photons. We report on a construction of an experimental setup with a large ~14 m2 spherical metallic mirror that will allow for searches of hidden-photon dark matter in the eV and sub-eV range by application of different electromagnetic radiation detectors. We discuss sensitivity and accessible regions in the dark matter parameter space.Comment: 9 pages, proceeding of the 34th International Cosmic Ray Conference (ICRC), July 30 - August 6, 2015, The Hague, The Netherland

    Enzyme Scaffolds with Hierarchically Defined Properties via 3D Jet Writing

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    The immobilization of enzymes into polymer hydrogels is a versatile approach to improve their stability and utility in biotechnological and biomedical applications. However, these systems typically show limited enzyme activity, due to unfavorable pore dimensions and low enzyme accessibility. Here, 3D jet writing of water‐based bioinks, which contain preloaded enzymes, is used to prepare hydrogel scaffolds with well‐defined, tessellated micropores. After 3D jet writing, the scaffolds are chemically modified via photopolymerization to ensure mechanical stability. Enzyme loading and activity in the hydrogel scaffolds is fully retained over 3 d. Important structural parameters of the scaffolds such as pore size, pore geometry, and wall diameter are controlled with micrometer resolution to avoid mass‐transport limitations. It is demonstrated that scaffold pore sizes between 120 µm and 1 mm can be created by 3D jet writing approaching the length scales of free diffusion in the hydrogels substrates and resulting in high levels of enzyme activity (21.2% activity relative to free enzyme). With further work, a broad range of applications for enzyme‐laden hydrogel scaffolds including diagnostics and enzymatic cascade reactions is anticipated.In this article, the development and application of a water‐based bioink with preloaded enzymes is described. With 3D jet writing, a hydrodynamic jetting system, freestanding 3D hydrogel frameworks with defined micropores are brightened. The enzyme‐loaded scaffolds show a high enzymatic activity and can be tested for industrial use in a continuous flow reactor over several days.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/162721/2/mabi202000154_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162721/1/mabi202000154.pd
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