1,066 research outputs found
Isolating Secular Signals in Observations and Climate Model Simulations Using M-SSA Based Wiener Filtering
In this thesis, Wiener filtering of gridded surface-temperature time series from observations and climate model simulations is performed by using multi-channel singular spectrum analysis (M-SSA) in order to isolate non-stationary climate signals. The contributions to the singular spectrum from shorter-term internal climate variability, treated in this context as noise, are estimated by fitting to the data spatially extended stochastic models, which are subsequently used to produce synthetic ensembles of surface temperature time series and the corresponding synthetic M-SSA spectra. The full spectra are weighted by the signal-to-noise ratios and transformed back to physical space to obtain reconstructions of the non-stationary signal. This methodology was first tested using the twentieth century simulations from the Community Earth System Model Large Ensemble Project, for which the forced climate signal can be reliably estimated by taking the ensemble average over the 40 available climate realizations, then applied to individual model ensembles as well as the overall ensemble from the Coupled Model Intercomparison Project Phase 5 and, finally, to the observational surface-temperature time series from Twentieth Century Reanalysis. The method is shown to successfully recover the low-frequency (decadal or larger time scales) component of the forced signal in model simulations, but fails to isolate shorter-term variability associated with volcanic eruptions. The secular signals estimated from model simulations and observations exhibit large differences, which indicates the presence, in observations, of a pronounced multi-decadal variability with a distinctive spatiotemporal structure absent in any of the model simulations
A novel ion channel formed by interaction of TRPML3 with TRPV5.
TRPML3 and TRPV5 are members of the mucolipin (TRPML) and TRPV subfamilies of transient receptor potential (TRP) cation channels. Based on sequence similarities of the pore forming regions and on structure-function evidence, we hypothesized that the pore forming domains of TRPML and TRPV5/TRPV6 channels have similarities that indicate possible functional interactions between these TRP channel subfamilies. Here we show that TRPML3 and TRPV5 associate to form a novel heteromeric ion channel. This novel conductance is detectable under conditions that do not activate either TRPML3 or TRPV5. It has pharmacological similarity with TRPML3 and requires functional TRPML3 as well as functional TRPV5. Single channel analyses revealed that TRPML3 and TRPV5 heteromers have different features than the respective homomers, and furthermore, that they occur in potentially distinct stoichiometric configurations. Based on overlapping expression of TRPML3 and TRPV5 in the kidney and the inner ear, we propose that TRPML3 and TRPV5 heteromers could have a biological function in these organs
Thermal and Mechanical Investigation of a Preload Release Mechanism for a Space Probe under Laboratory Conditions
Der Vorspannungsabbau-Mechanismus der Asteroidenlandeeinheit MASCOT soll auf seine Funktionalität untersucht werden. Dazu muss ein Teststand entwickelt werden. Zusätzlich soll der Mechanismus derart verändert werden, dass der Erfolg des Abbauvorganges während des Fluges überprüft werden kann
Endogenous leukemia inhibitory factor protects photoreceptor cells against light-induced degeneration
PURPOSE: Expression of leukemia inhibitory factor (LIF) by a subset of Müller glia cells has recently been implicated in an endogenous survival response to photoreceptor injury in a model of inherited retinal degeneration. To investigate whether such a LIF-controlled survival pathway might be commonly induced upon photoreceptor injury independently of the nature of the toxic stimulus, we analyzed the role of LIF during light-induced retinal degeneration. METHODS: Lif(+/-) and Lif(-/-) mice were exposed to 15,000 lx of white light for 2 h. Retinal morphology and rhodopsin content were analyzed nine days after light exposure. Gene expression studies were done using real-time PCR. Protein levels were determined by western blotting using specific antibodies. RESULTS: A lack of LIF reduced survival of photoreceptor cells after light exposure. In the absence of LIF several genes encoding molecules involved in the Janus kinase/signal transducer and activator of transcription (Jak/STAT) signaling pathway were not activated after light exposure. Presence or absence of LIF did not affect AKT (also known as protein kinase B, PKB) signaling and had only a mild effect on extracellular regulated kinase (ERK) phosphorylation. Stress-induced glial fibrillary acidic protein (GFAP) induction was minimal in the absence of LIF. CONCLUSIONS: Our results suggest that increased retinal expression of LIF is a general response to photoreceptor injury. Independent of the nature of the toxic insult (gene mutation, light), LIF may activate an endogenous rescue pathway that protects viable photoreceptor cells, leading to an increased photoreceptor survival in the stressed retina. This defense system may depend on the Jak/STAT pathway and may involve endothelin 2 (EDN2) but not (or only minimally) AKT and ERK1,2 signaling
On the current state of German-speaking economics: Paradigmatic orientations and political alignments of German-speaking economists
A sample of 708 full professors (Lehrstuhlinhaber_innen) of economics at German-speaking universities (Austria, Germany and Switzerland). Very low percentage of female economists (13%). Dominance of microeconomic research orientation (50.35%). Paradigmatic classification based on two approaches reveals strong dominance of a neoclassical mainstream (91.27% and 76.11%). Heterodox approaches are marginalized and situated at small universities (e.g. Bremen, Darmstadt, Oldenburg, Lüneburg and Jena). Rather strong reference to ordoliberal concepts in Germany (8.04%). Only a minority of German-speaking economists is doing research on the financial crisis (14.45%). The German Economic Association is by far the most important academic association (60% are member of the GEA). A substantial part of German-speaking economists (particularly from those active in economic policy advice) are connected to ordoliberal and German neoliberal think tanks, institutions and initiatives (e.g. Walter Eucken Institute, Kronberger Kreis, INSM or the Hamburger Appell)
Dosimetria da pena utilizando redes neurais
Análise da viabilidade do uso de redes neurais artificiais como instrumentos de apoio aos operadores do Direito, seguido pela confecção de um exemplo de aplicação das mesmas, na dosimetria da pena. Faz-se uma análise histórica da dosimetria da pena até o sistema trifásico dos dias atuais, que passa a ser detalhado em suas circunstâncias judiciais e legais. Procede-se à explanação da origem e funcionamento das redes neurais artificiais, seguida de considerações acerca de sua compatibilidade com a forma de pensar jurÃdica. Projeta-se uma rede neural artificial, escolhendo-se tanto sua arquitetura quanto sua plataforma de implementação, para atuar na etapa de fixação da pena base da dosimetria da pena. Através de um conjunto de julgamentos hipotéticos para um mesmo magistrado, treina-se a rede neural artificial projetada. Verifica-se que o treinamento é bem-sucedido, com a rede neural artificial fornecendo exatamente a mesma pena base que o magistrado hipotético fixou para as circunstâncias judiciais apresentadas. Com a apresentação à rede neural artificial de novos conjuntos de circunstâncias judiciais, pode-se observar nuances no julgamento que não seriam possÃveis de serem observadas de outra forma. Atesta-seque a rede neural artificial, além de, com um treinamento adequado, poder reproduzir o comportamento de um magistrado, é capaz também de evidenciar a preponderância de alguns fatores sobre outros, na determinação da pena
Solving three major biases of the ETAS model to improve forecasts of the 2019 Ridgecrest sequence
Strong earthquakes cause aftershock sequences that are clustered in time according to a power decay law, and in space along their extended rupture, shaping a typically elongate pattern of aftershock locations. A widely used approach to model earthquake clustering, the Epidemic Type Aftershock Sequence (ETAS) model, shows three major biases. First, the conventional ETAS approach assumes isotropic spatial triggering, which stands in conflict with observations and geophysical arguments for strong earthquakes. Second, the spatial kernel has unlimited extent, allowing smaller events to exert disproportionate trigger potential over an unrealistically large area. Third, the ETAS model assumes complete event records and neglects inevitable short-term aftershock incompleteness as a consequence of overlapping coda waves. These three aspects can substantially bias the parameter estimation and lead to underestimated cluster sizes. In this article, we combine the approach of Grimm et al. (Bulletin of the Seismological Society of America, 2021), who introduced a generalized anisotropic and locally restricted spatial kernel, with the ETAS-Incomplete (ETASI) time model of Hainzl (Bulletin of the Seismological Society of America, 2021), to define an ETASI space-time model with flexible spatial kernel that solves the abovementioned shortcomings. We apply different model versions to a triad of forecasting experiments of the 2019 Ridgecrest sequence, and evaluate the prediction quality with respect to cluster size, largest aftershock magnitude and spatial distribution. The new model provides the potential of more realistic simulations of on-going aftershock activity, e.g. allowing better predictions of the probability and location of a strong, damaging aftershock, which might be beneficial for short term risk assessment and disaster response
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