1,720,975 research outputs found
Serum Free Medium
No full textIn-vitro cell-based assays are widely used to characterize a molecule's bioactivity or quantify the potency of clinical and marketed drugs, as requested by regulatory authorities. Fetal Bovine Serum (FBS) is the gold standard of cell supplements but at the same time, it is one of the most critical reagents for cell culture. Firstly, FBS collection causes suffering to animals. Secondly, FBS is one of the higher sources of cell culture contamination. Finally, FBS composition is not completely characterized, and this could lead to batch-to-batch variability. Therefore, the idea is to adapt the HEK-293T cells to grow in a homemade Serum-Free Medium (SFM) where each media component is known, chemically characterized, and replaceable by the user
Advertising investments on television: real option estimation through Markov chains
Full text linkWe propose the valuation of a real option in the telecommunications industry. According to the probabilistic present worth approach, we estimate the value of a contract between a television network and a company willing to advertise its business on this network. We assume that the value of the contract depends on a time-dependent variable, i.e., the number of viewers tuned into the network, which behaves like a Markov process. After discretizing and converting this number into a monetary value through a specific function, we compute the nth-order moment of the total discounted earnings. The knowledge of the moments, and the application of the maximum-entropy approach, allows to find the probability distribution of the payoff function and the consequential pricing of the real option. Finally, we apply the proposed model to the real television audience data
Parametric study of the influence of the wind assisted propulsion on ships
No full textnologies to increase energy efficiency and reduce ship fuel consumption. Several measures have been identified, or even applied, with the potential to achieve substantial fuel consumption and emission reductions, like slow-steaming, bio-fuels, and alternative propulsion technologies. Slow steaming has been already analysed to a great extent, whereas biofuels have raised concerns about environmental impact and availability. Among alternative propulsion technologies, a resurgence in wind-assisted propulsion is observed in recent years, primarily due to its high potential for fuel consumption and emission reduction. Wind power is currently being developed through both conventional sails and modern alternatives. These include Flettner rotors, kites or spinnakers, soft sails, wing sails and wind turbines. In particular, Flettner rotors are rotating cylinders generating lift when immersed in a fluid stream. This paper presents a ship propulsion model study, able to account for the thrust force produced by the rotor accounting for different vessel speed and weather scenario. This paper aims to assess the improvement of the ship’s energy efficiency and optimise the ship operating conditions in terms of daily performance. The result clearly shows the potential reduction achieved in the propeller delivered power given using the rotor as an auxiliary propulsion device
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Marine Pollution Mitigation by Waste Oils Recycling Onboard Ships: Technical Feasibility and Need for New Policy and Regulations
No full textAbout 80% of the total pollution from ships is caused by operational oil discharges into the sea, often made deliberately and in violation of international rules; the main reasons can be due to cost savings or lack of adequate facilities in ports to receive waste oils. Therefore, reducing waste oil discharges is crucial for a proper protection of the marine environment. In this regard, the paper presents the preliminary feasibility of a particular waste recycling technology, aimed at obtaining marine fuel oil from sludge, through a pyrolysis process to be carried out in a small reactor onboard. The originality of the research consists in the adaptation of pyrolysis to oily waste produced by ships, since this technology is traditionally applied to solid waste and biomass. Furthermore, the plant has to be designed for operation on board the ship, therefore under very different constraints compared to traditional land plants. Although the preliminary lab tests and simulation results in the chemical process are promising enough, there are still some technical criticalities due to the energy optimization of the reactor for an efficient use onboard of the whole system. In addition, the possibility of recycling waste, directly onboard ships, is not yet covered by mandatory regulations, which is why shipowners generally still feel unmotivated to invest in such technologies
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Energy efficiency analysis of a flexible marine hybrid propulsion system
No full textThe paper analyses some advantages of the hybrid ship propulsion, enhanced by the use of some energy recovery technologies. The concept design of a power plant for a Ro-Ro ferry is presented as a case study, since this particular ship can best take advantage of the operational flexibility of this propulsion type. As an element of innovation, the hybrid propulsion flexibility is analysed taking into account the installation onboard of dual fuel engines. This leads to examine the influence of natural gas, being rather different from traditional diesel oil in performance and price, on the propulsion system efficiency and fuel cost saving. Moreover, technical solutions as the waste heat recovery from the exhaust gas of the engine, equipped with innovative hybrid turbochargers, are also considered to produce additional electric energy, improving the overall efficiency of the vessel
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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