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Book reviews     
Affiliated to Astrophysics Div., Space Science Department, European Space Agency.  相似文献   
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IntroductionSensorydataareusedinfoodindustryforsensoryevaluationaswellasforprocesscontrol.Sensoryevaluationisusedwhenthefinalproductqualitycannotbeeasilyputinrelationtothecorrespondingmanufacturingparameters.Thisisparticularlyrelevantforfoodproducts,wherequalityfactorsperceivedbyconsumersaredifficulttorelatetochemicalorphysicalcomponentcharacteristics.Therearemanydifferentkindsofproblemsinwhichsensoryevaluationisnecessary:Newproductdevelopment,costreductionexercises,qualityimprovement,evaluat…  相似文献   
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The complexity of local situations in which agricultural value chains are enacted requires a systemic understanding when seeking to improve interlinked livelihoods. Studying the fresh pineapple value chain in Uganda offers an illustrative example. Individually negotiated and context-specific actor relationships, along with their connected activities can be revealed by conceptualizing the chain as a purposeful human activity system. We followed a systems learning approach to elicit value chain actors’ perspectives on factors influencing their activities while surfacing relevant problem situations, resolutions and constraints. Participatory methods, including cognitive mapping, were used to spark dialogue during meetings with only farmers, traders and brokers and also with mixed groups. The results present the multiple natural, technical and social factors identified by value chain actors leading to losses and benefits to their income. System driving and shaping influences included infrastructure, seasonality, perishability and weather conditions. Process-oriented analysis of multi-stakeholder discussions revealed feedback cycles related to fragmentation of the chain. This resulted from and contributed to problematic communication, price fluctuations and challenges in actor relations. For example, actors proposed uniform pricing and debated the implications. Although the systemic perspective brought forward actors’ awareness of potential benefits of improved collaboration and recognition of interdependent activities, it also exposed barriers. Participatory systems learning helped to capture actors’ room of maneuver, and can support processes towards actor-driven change.  相似文献   
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Retraction of mesenchymal stromal cells supports the invasion of colorectal cancer cells (CRC) into the adjacent compartment. CRC-secreted 12(S)-HETE enhances the retraction of cancer-associated fibroblasts (CAFs) and therefore, 12(S)-HETE may enforce invasivity of CRC. Understanding the mechanisms of metastatic CRC is crucial for successful intervention. Therefore, we studied pro-invasive contributions of stromal cells in physiologically relevant three-dimensional in vitro assays consisting of CRC spheroids, CAFs, extracellular matrix and endothelial cells, as well as in reductionist models. In order to elucidate how CAFs support CRC invasion, tumour spheroid-induced CAF retraction and free intracellular Ca2+ levels were measured and pharmacological- or siRNA-based inhibition of selected signalling cascades was performed. CRC spheroids caused the retraction of CAFs, generating entry gates in the adjacent surrogate stroma. The responsible trigger factor 12(S)-HETE provoked a signal, which was transduced by PLC, IP3, free intracellular Ca2+, Ca2+-calmodulin-kinase-II, RHO/ROCK and MYLK which led to the activation of myosin light chain 2, and subsequent CAF mobility. RHO activity was observed downstream as well as upstream of Ca2+ release. Thus, Ca2+ signalling served as central signal amplifier. Treatment with the FDA-approved drugs carbamazepine, cinnarizine, nifedipine and bepridil HCl, which reportedly interfere with cellular calcium availability, inhibited CAF-retraction. The elucidation of signalling pathways and identification of approved inhibitory drugs warrant development of intervention strategies targeting tumour–stroma interaction.  相似文献   
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The paper investigates Kant's pre-critical views on the use of analytic and synthetic methods in Newtonian science and in philosophical reasoning. In his 1755/56 writings, Kant made use of two variants of the analytic method, i.e., conceptual analysis in a Cartesian (or Leibnizean) sense, and analysis of the phenomena in a Newtonian sense. His Prize Essay (1764) defends Newton's analytic method of physics as appropriate for philosophy, in contradistinction to the synthetic method of mathematics. A closer look, however, shows that Kant does not identify Newton's method with conceptual analysis, but just suggests a methodological analogy between both methods. Kant’s 1768 paper on incongruent counterparts also fits in with his pre-critical use of conceptual analysis. Here, Kant criticizes Leibniz’ relational concept of space, arguing that it is incompatible with the phenomenon of chiral objects. Since this result was in conflict with his pre-critical views about space, Kant abandoned the analytic method of philosophy in favour of his critical method. The paper closes by comparing Kant's pre-critical analytic method and the way in which he once again took up the methodological analogy between Newtonian science and metaphysics, in the preface B to the Critique of Pure Reason, in the context of his thought experiment of pure reason.  相似文献   
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This paper presents an activity and knowledge analysis using second-order cybernetics for analysing human activities in social-ecological systems. We do this with the case of smallholder farmers producing milk in Nakuru County, Kenya. The analysis is based on farmers′ actions and the knowledge behind their actions. Using this approach, we analysed how smallholder farmers regulate milk production and how they influence milk quality. Farmers influence milk quality with their routine and problem-solving management actions. The knowledge behind these actions can be represented as rules. We found that Routine Control Rules that influence milk quality aim to (i) minimize contamination (ii) maintain udder health, and (iii) preserve milk. Problem-Solving Control Rules aim to deal with disturbances associated with (i) market imperfection (ii) microbiological contamination (iii) disease, and (iv) unfavourable milk composition. The approach revealed key restrictions and disturbance factors influencing milk quality in smallholder dairy systems. It also allowed for co-identification of best practices and entry points for contextualized innovations, i.e. innovations that fit into the respective production context. The co-analysis led to changes in farmers’ practices, as it fostered the co-development of milk quality standards to be applied at the community level as preparation for collective marketing activities. When emphasis is placed on finding restrictions and developing innovations, the approach can be further applied to other land-use systems.  相似文献   
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The seasonal polar ice caps of Mars are composed mainly of CO2 ice. A region of low (< 30%) albedo has been observed within the south seasonal cap during early to mid-spring. The low temperature of this 'cryptic region' has been attributed to a clear slab of nearly pure CO2 ice, with the low albedo resulting from absorption by the underlying surface. Here we report near-infrared imaging spectroscopy of the south seasonal cap. The deep and broad CO2 absorption bands that are expected in the near-infrared with a thick transparent slab of CO2 ice are not observed. Models of the observed spectra indicate that the low albedo results from extensive dust contamination close to the surface of a CO2 ice layer, which could be linked to atmospheric circulation patterns. The strength of the CO2 absorption increases after mid-spring, so part of the dust is either carried away or buried more deeply in the ice layer during the CO2 ice sublimation process.  相似文献   
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