132 research outputs found
Atmospheric Response to Ice-Age Conditions - Climatology near the Earth's Surface
We present a 6-year simulation of the ice age atmosphere using the T21 Atmospheric General Circulation Model (AGCM) of the European Centre for Medium-Range Weather Forecasts (ECMWF). The lower boundary conditions (18 kyr B.P.) were taken from CLIMAP Project Members (1981). The analysis is restricted to the surface climatology for two reasons: The surface fields are the test data derived from the geological record on land, and they define the upper boundary conditions for simulating the glacial ocean. Model results are shown for the mean annual surface fields of temperature, wind, and precipitation. In the global average the surface temperature was 4.7øC cooler compared to the present temperature. The wind strength increased in mid-latitudes and decreased in tropical trade wind regions. Precipitation did not change significantly in the global average; however, precipitation decreased over land and increased over the ocean. Most of the difference patterns between the present conditions and the ice age climate were statistically significant. The simulated surface climatology is roughly consistent with the paleogeological evidence and with numerical AGCM simulations of other authors. This suggests that presently available AGCMs, including the ECMWF model (T21), are able to describe climates far away from the present, although internal parameteriza- tions were tuned to present data sets
Understanding the Business Value: Towards a Taxonomy of Industrial Use Scenarios enabled by Cyber-Physical Systems in the Equipment Manufacturing Industry
The trend of digitalization provides new opportunities for industrial equipment manufactures as sensor technology and ubiquitous connectivity become part of the equipment. In particular, cyber-physical systems (CPSs) enable digital innovation for the industrial product and service business by improving operational efficiencies, facilitating innovative hybrid business models, and fuelling servitization in manufacturing. Despite the new opportunities, so far no research has been conducted to investigate and classify configurations and affordances of this new technology. To gain both a broad and in-depth understanding of use scenarios and added-value of CPSs for the service business in the equipment industry, a multi-method approach is chosen: a systematic literature review as well as case study research are conducted. Grounded in existing literature and based on empirical data of 45 use scenarios, we propose a taxonomy to classify use scenarios enabled by CPSs in the equipment industry. This work contributes to the theoretical body of knowledge by proposing a taxonomy of use scenarios enabled by CPSs. The taxonomy can be (1) leveraged to categorize use scenarios of CPSs in the equipment manufacturing industry and (2) used as a framework for further research. Practitioners can use the taxonomy to classify and compare use scenarios as well as identify business model archetypes
Implications of automatic photon quenching on compact gamma-ray sources
Aims: We investigate photon quenching in compact non-thermal sources. This
involves photon-photon annihilation and lepton synchrotron radiation in a
network that can become non-linear. As a result the gamma-ray luminosity of a
source cannot exceed a critical limit that depends only on the radius of the
source and on the magnetic field. Methods: We perform analytic and numerical
calculations that verify previous results and extend them so that the basic
properties of photon quenching are investigated. Results: We apply the above to
the 2006 TeV observations of quasar 3C279 and obtain the parameter space of
allowed values for the radius of the emitting source, its magnetic field
strength and the Doppler factor of the flow. We argue that the TeV observations
favour either a modest Doppler factor and a low magnetic field or a high
Doppler factor and a high magnetic field.Comment: 10 pages, 12 figures, accepted for publication in Astronomy and
Astrophysic
Liquid interactions with porous media and the fate of toxic materials
Toxic liquid chemicals released into the environment may pose an imme- diate risk to human health through contact or related vapour hazards. However, they can also interact with surfaces and remain in situ, poten- tially presenting a subsequent hazard. To improve understanding of the fate of these materials in different environments, the study group inves- tigated interactions between liquid droplets and porous media across a range of different time scales.
Splashing and the subsequent re-entrainment of micro-droplets into the atmosphere was identified as one possible mechanism though which the area effect of a contamination could be significantly increased. The study group looked at experimentally determined splashing thresholds for droplet impacts with impermeable substrates, to determine initial predictions of whether or not a given droplet will splash. In cases where splashing occurs the droplet inertia is the most significant effect driving the initial phase of the liquid infiltration into a porous media and the study group developed a model to investigate this behaviour.
For longer time scales the study group determined that capillary suction played the most significant role in spreading the liquid within the porous medium. Models for the evolution of the partial saturation within a porous medium based on Richards’ equation were investigated. Over even longer time scales evaporation converts the liquid back into a po- tentially hazardous vapour. The study group started to incorporate evaporation into models of liquid infiltration in a porous medium in order to describe this phenomenon. Recommendations for future theo- retical, numerical and experimental modelling are also provided
The emergence of smart service ecosystems : the role of socio‐technical antecedents and affordances
As physical products are increasingly augmented with digital technology, manufacturing firms have become part of the development of so-called smart products and smart services. As such, manufacturing firms are challenged by new market participants and ecosystem partners, particularly from the software development industry, and by the dynamic nature of business relationships. While the academic literature on the distinctive characteristics of ecosystems, particularly digital ecosystems, is rich, the effect of smart service ecosystems' emergence on the foundation of smart products remains uncertain. This study reports on case study research based on 47 semi-structured interviews with four companies that participate in an industrial smart service ecosystem. Taking an affordance-theoretic perspective, we uncover the antecedents of and the process of emergent smart service ecosystems. We find that smart service ecosystems have three socio-technical antecedents: a shared worldview, structural flexibility and integrity, and architecture of participation. We explain the emergence of smart service ecosystems as the result of specialisation in shared affordances and integration of idiosyncratic affordances into collective affordances. We derive seven propositions regarding the emergence of smart services, outline opportunities for further research, and present practical guidelines for manufacturing firms
The genetic contribution of the NO system at the glutamatergic post-synapse to schizophrenia : further evidence and meta-analysis
NO is a pleiotropic signaling molecule and has an important role in cognition and emotion. In the brain, NO is produced by neuronal nitric oxide synthase (NOS-I, encoded by NOS1) coupled to the NMDA receptor via PDZ. interactions; this protein-protein interaction is disrupted upon binding of NOS1 adapter protein (encoded by NOS1AP) to NOS-I. As both NOS1 and NOS1AP were associated with schizophrenia, we here investigated these genes in greater detail by genotyping new samples and conducting a meta-analysis of our own and published data. In doing so, we confirmed association of both genes with schizophrenia and found evidence for their interaction in increasing risk towards disease. Our strongest finding was the NOS1 promoter SNP rs41279104, yielding an odds ratio of 1.29 in the meta-analysis. As findings from heterologous cell systems have suggested that the risk allele decreases gene expression, we studied the effect of the variant on NOS1 expression in human post-mortem brain samples and found that the risk allele significantly decreases expression of NOS1 in the prefrontal cortex. Bioinformatic analyses suggest that this might be due the replacement of six transcription factor binding sites by two new binding sites as a consequence of proxy SNPs. Taken together, our data argue that genetic variance in NOS1 resulting in lower prefrontal brain expression of this gene contributes to schizophrenia liability, and that NOS1 interacts with NOS1AP in doing so. The NOS1-NOS1AP PDZ interface may thus well constitute a novel target for small molecules in at least some forms of schizophrenia. PostprintPeer reviewe
Empowering production workers with digitally facilitated knowledge processes--a conceptual framework
A mouse model for Sorsby fundus dystrophy
purpose. Sorsby fundus dystrophy (SFD) is a rare, late-onset macular dystrophy caused by mutations in the tissue inhibitor of metalloproteinases-3 (TIMP3) gene. The known mutations introduce potentially unpaired cysteine residues in the C terminus of the protein and result in the formation of higher-molecular-weight protein complexes of as yet unknown composition and functional consequences in the pathologic course of SFD. To facilitate in vivo investigation of mutant TIMP3, the authors generated a knock-in mouse carrying a disease-related Ser156Cys mutation in the orthologous murine Timp3 gene.
methods. Site-directed mutagenesis and homologous recombination in embryonic stem (ES) cells was used to generate mutant ES cells carrying the Timp3 S156C allele. Chimeric animals were obtained, of which two displayed germline transmission of the mutated allele. Molecular genetic, biochemical, electron microscopic, and electrodiagnostic techniques were used for characterization.
results. At 8 months of age, knock-in mice showed abnormalities in the inner aspect of Bruch’s membrane and in the organization of the adjacent basal microvilli of the retinal pigment epithelium (RPE). Changes resembling those in the mutant animals were also present to some extent in normal littermates, but only at an advanced age of 30 months. Long-term electrodiagnostic recordings indicated normal retinal function throughout life. The biochemical characteristics of the mutant protein appear similar in humans and knock-in mice, suggesting common molecular pathways in the two species. The localization of the mutant protein in the eye is normal, although there is evidence of increased Timp3 levels in Bruch’s membrane of mutant animals.
conclusions. The knock-in mice display early features of age-related changes in Bruch’s membrane and the RPE that may represent the primary clinical manifestations of SFD. In addition, our immunolabeling studies and biochemical data support a model proposing that site-specific excess rather than absence or deficiency of functional Timp3 may be the primary consequence of the known Timp3 mutations
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