458 research outputs found
Exploring Design Requirements of Fleet Telematics Systems Supporting Road Freight Transportation: A Digital Service Side Perspective
Road freight operators (RFOs) optimize their fleet management processes using fleet telematics systems (FTSs). Therefore, the selection of FTSs by RFOs is driven by transport specifications from the customer side leading to substantial search costs. However, FTSs vary significantly in their design requirements to assist road freight operations. Hence, we analyze 74 web pages from FTSs of existing telematics vendors to elicit 31 design requirements (DRs) which we aggregated into nine requirement sets (RSs). Subsequently, 42 practitioners from five digital road freight service enterprises experienced in using FTSs validate the DRs and evaluate their importance with RSs following the Analytical Hierarchy Process (AHP) method. The results reveal that DRs and RSs promoting driver monitoring and IT integration are perceived more important than items promoting fleet and logistics support. Our contribution sheds light on an emerging topic in logistics and establishes a knowledge base that guides the design of future FTSs
Chemical composition of modern and fossil Hippopotamid teeth and implications for paleoenvironmental reconstructions and enamel formation: 1. major and minor element variation [Discussion paper]
Bioapatite in mammalian teeth is readily preserved in continental sediments and represents a very important archive for reconstructions of environment and climate evolution. This project intends to provide a detailed data base of major, minor and trace element and isotope tracers for tooth apatite using a variety of microanalytical techniques. The aim is to identify specific sedimentary environments and to improve our understanding on the interaction between internal metabolic processes during tooth formation and external nutritional control and secondary alteration effects. Here, we use the electron microprobe, to determine the major and minor element contents of fossil and modern molar enamel, cement and dentin from hippopotamids. Most of the studied specimens are from different ecosystems in Eastern Africa, representing modern and fossil lakustrine (Lake Kikorongo, Lake Albert, and Lake Malawi) and modern fluvial environments of the Nile River system.
Secondary alteration effects in particular FeO, MnO, SO3 and F concentrations, which are 2 to 10 times higher in fossil than in modern enamel; secondary enrichments in fossil dentin and cement are even higher. In modern and fossil enamel, along sections perpendicular to the enamel-dentin junction (EDJ) or along cervix-apex profiles, P2O5 and CaO contents and the CaO/P2O5 ratios are very constant (StdDev ~1 %). Linear regression analysis reveals very tight control of the MgO (R2∼0.6), Na2O and Cl variation (for both R2>0.84) along EDJ-outer enamel rim profiles, despite large concentration variations (40 % to 300 %) across the enamel. These minor elements show well defined distribution patterns in enamel, similar in all specimens regardless of their age and origin, as the concentration of MgO and Na2O decrease from the enamel-dentin junction (EDJ) towards the outer rim, whereas Cl displays the opposite variation.
Fossil enamel from hippopotamids which lived in the saline Lake Kikorongo have a much higher MgO/Na2O ratio (∼1.11) than those from the Neogene fossils of Lake Albert (MgO/Na2O∼0.4), which was a large fresh water lake like those in the western Branch of the East African Rift System today. Similarly, the MgO/Na2O ratio in modern enamel from the White Nile River (∼0.36), which has a Precambrian catchment of dominantly granite and gneisses and passes through several saline zones, is higher than that from the Blue Nile River, whose catchment is the Neogene volcanic Ethiopian Highland (MgO/Na2O∼0.22). Thus, particularly MgO/Na2O might be a sensitive fingerprint for environments where river and lake water have suffered strong evaporation.
Enamel formation in mammals takes place at successive mineralization fronts within a confined chamber where ion and molecule transport is controlled by the surrounding enamel organ. During the secretion and maturation phases the epithelium generates different fluid composition, which in principle, should determine the final composition of enamel apatite. This is supported by co-linear relationships between MgO, Cl and Na2O which can be interpreted as binary mixing lines. However, if maturation starts after secretion is completed the observed element distribution can only be explained by recrystallization of existing and addition of new apatite during maturation. Perhaps the initial enamel crystallites precipitating during secretion and the newly formed bioapatite crystals during maturation equilibrate with a continuously evolving fluid. During crystallization of bioapatite the enamel fluid becomes continuously depleted in MgO and Na2O, but enriched in Cl which results in the formation of MgO, and Na2O-rich, but Cl-poor bioapatite near the EDJ and MgO- and Na2O-poor, but Cl-rich bioapatite at the outer enamel rim.
The linkage between lake and river water composition, bioavailability of elements for plants, animal nutrition and tooth formation is complex and multifaceted. The quality and limits of the MgO/Na2O and other proxies have to be established with systematic investigations relating chemical distribution patterns to sedimentary environment and to growth structures developing as secretion and maturation proceed during tooth formation
Species-independent bioassay for sensitive quantification of antiviral type I interferons
<p>Abstract</p> <p>Background</p> <p>Studies of the host response to infection often require quantitative measurement of the antiviral type I interferons (IFN-α/β) in biological samples. The amount of IFN is either determined via its ability to suppress a sensitive indicator virus, by an IFN-responding reporter cell line, or by ELISA. These assays however are either time-consuming and lack convenient readouts, or they are rather insensitive and restricted to IFN from a particular host species.</p> <p>Results</p> <p>An IFN-sensitive, <it>Renilla </it>luciferase-expressing Rift Valley fever virus (RVFV-Ren) was generated using reverse genetics. Human, murine and avian cells were tested for their susceptibility to RVFV-Ren after treatment with species-specific IFNs. RVFV-Ren was able to infect cells of all three species, and IFN-mediated inhibition of viral reporter activity occurred in a dose-dependent manner. The sensitivity limit was found to be 1 U/ml IFN, and comparison with a standard curve allowed to determine the activity of an unknown sample.</p> <p>Conclusions</p> <p>RVFV-Ren replicates in cells of several species and is highly sensitive to pre-treatment with IFN. These properties allowed the development of a rapid, sensitive, and species-independent antiviral assay with a convenient luciferase-based readout.</p
Towards a Framework for Predictive Maintenance Strategies in Mechanical Engineering – A Method-Oriented Literature Analysis
Industrial machines are amongst Germany’s main export products and contribute to the increasing revenue of Mechanical Engineering. However, in the course of globalization, services for such machines have become costly and inflexible due to long distances between vendors and customers. Consequently, companies seek to avoid unexpected failures and long down times by the development of data-based “smart” service solutions, including Predictive Maintenance (PM). In contrast to reactive or preventive measures, PM refers to the proactive planning of required maintenance services based on data sampled from the machinery. Although PM has been conceptualized decades ago and various methods have been proposed ever since, there is no standard strategy. By analyzing existing literature, we shed light on the knowledge base in PM. We provide an overview of methods and discuss their respective context, including preconditions and applications. Our work constitutes a first step towards a framework that guides the implementation of PM-strategies
SCRUTINIZING THE DESIGN SPECIFICATIONS OF SMART PRODUCTS: A PRACTICAL EVALUATION IN YACHTING
The collection and use of data are of increasing importance not only in virtual worlds but also for real goods. New products operationalize this principle and integrate sensors, actuators and microcomputers into analog products to enable sophisticated features such as context-awareness or connectivity with other devices. The underlying concept is being discussed as Smart Product and aims for the automation of activities, right up to autonomization of entire products. This article raises design specifications from existing literature and instantiates Smart Products in sailing. We discuss the application of the design specifications with sailing professionals in order to evaluate its practical value and to identify further benefits. The results affirmed that sailboats can be transformed into Smart Products by the integration of information technology. However, it also turned out that additional benefits can only be tapped by the integration of further stakeholders in a systemic perspective
Comparison of Cognitive Learning Growth in Occupational Achievement in Minumum/Medium Security Inmates Enrolled in Vo-Tech Skills Centers and Postsecondary Students Enrolled in Area Vocational-Technical Schools in Oklahoma
Occupational and Adult Educatio
A spatial correlation model of peak ground acceleration and response spectra based on data of the Istanbul Earthquake Rapid Response and Early Warning System
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