814 research outputs found
Single-gene knockout of a novel regulatory element confers ethionine resistance and elevates methionine production in Corynebacterium glutamicum
Despite the availability of genome data and recent advances in methionine regulation in Corynebacterium glutamicum, sulfur metabolism and its underlying molecular mechanisms are still poorly characterized in this organism. Here, we describe the identification of an ORF coding for a putative regulatory protein that controls the expression of genes involved in sulfur reduction dependent on extracellular methionine levels. C. glutamicum was randomly mutagenized by transposon mutagenesis and 7,000 mutants were screened for rapid growth on agar plates containing the methionine antimetabolite d,l-ethionine. In all obtained mutants, the site of insertion was located in the ORF NCgl2640 of unknown function that has several homologues in other bacteria. All mutants exhibited similar ethionine resistance and this phenotype could be transferred to another strain by the defined deletion of the NCgl2640 gene. Moreover, inactivation of NCgl2640 resulted in significantly increased methionine production. Using promoter lacZ-fusions of genes involved in sulfur metabolism, we demonstrated the relief of l-methionine repression in the NCgl2640 mutant for cysteine synthase, o-acetylhomoserine sulfhydrolase (metY) and sulfite reductase. Complementation of the mutant strain with plasmid-borne NCgl2640 restored the wild-type phenotype for metY and sulfite reductas
From Titanic to Costa Concordia—a century of lessons not learned
The recent foundering of the Costa Concordia in January 2012 demonstrated
that accidents can occur even with ships that are considered masterpieces of
modern technology and despite more than 100 years of regulatory and technological
progress in maritime safety. The purpose of this paper is, however, not to speculate
about the concrete causes of the Costa Concordia accident, but rather to consider
some human and organizational factors that were present in the Costa Concordia
accident as well as in the foundering of the Titanic a century ago, and which can be
found in many other maritime accidents over the years. The paper argues that these
factors do not work in isolation but in combination and often together with other
underlying factors. The paper critically reviews the focus of maritime accident
investigations and points out that these factors do not receive sufficient attention. It
is argued that the widespread confidence in the efficacy of new or improved technical
regulations, that characterizes the recommendations from most maritime accident
investigations, has led to a lack of awareness of complex interactions of factors and
components in socio-technical systems. If maritime safety is to be sustainably
improved, a systemic focus must be adopted in future accident investigations
Критерии формы поперечного сечения взрывной скважины
Предложены критерии оценки форм поперечного сечения скважины, полностью заполненной удлиненным зарядом взрывчатого вещества. Критерии рассмотрены с точки зрения эффективности взрывного воздействия на горную породу и могут быть использованы при создании и обосновании конструкций бурового инструмента. Анализ геометрических форм поперечных сечений взрывной полости в виде правильных фигур показал, что имеется взаимосвязь критериев, конкретное значение которых может быть определено для имеющихся конструкций бурового инструмента.Proposed criteria for the assessment of the bag of cross-section of the borehole is completely filled elongated explosive charge. Criteria considered from the point of view of the ability to influence the result of the explosive impact and can be used to create and justify the constructions of the drilling tool. The analysis of geometrical forms of cross sections of the explosive borehole in the form of correct figures have shown that there is a relationship of the considered criteria, however, a specific value can be determined for the existing designs of drilling tools
After 40 years of regional and coordinated ship safety inspections: Destination reached or new point of departure?
Port State Control (PSC) is the major global strategy for fighting substandard shipping since the signature of The Hague Memorandum in 1978. In the last years, the increased volume of trade, the enlarged number of main international conventions and the highlighted differences among the various Regimes have posed new challenges to the modern system of PSC, which may need to find its new course. This paper examines the point of view of key maritime stakeholders with regard to the EU PSC regime. Elite interviews (n = 14) were conducted with subject matter experts ranging from policy makers, to industry and seafarers’ representatives. The study aims to determine factors leading to difference in treatment among EU Member States. The study concludes that PSC in Europe seems to be the most efficient and reliable of the regional agreement on PSC. However, some discrepancies during the inspection process and outcome can be highlighted due to differences at the inspector and Member State level
Making the case for Crew-Centered Design (CCD) in merchant shipping
Since 2003, the International Maritime Organization (IMO) has emphasised the need to address and integrate ergonomics knowledge in a concerted manner. However, there is little guidance on the application of this knowledge in the design of merchant vessels. Utilizing a mixed methods approach, the paper identifies the need for crew-centered design (CCD), highlighting the importance of using concepts derived from Human-Centred Design (HCD) to be able to design work spaces and operational procedures that facilitate the work of the crew on board. Drawing upon results obtained from accident analysis (utilising the Technique for the Retrospective and predictive Analysis of Cognitive Errors - TRACEr) and 24 semi-structured interviews, this paper identifies areas in which it could be potentially beneficial to integrate end-users in the design of ships and shipborne operations. This paper further discusses why and how concepts rooted in HCD could be used to improve maritime workspace and interface design, as well as the design of procedures and shipborne operations. However, due to the specifics of the maritime domain, the authors propose that there is the need to expand the HCD perspective, making the design not only fit a single user, but to fit the crew as part of a maritime socio-technical system. The paper discusses that the case for CCD is imperative in the interest of safety, efficiency and even makes economic sense
Safety of domestic ferries: A scoping study of seven high-risk countries
Ferry accidents are fairly common globally, causing countless deaths and injuries. Whereas ferry transportation is an integral part of the domestic transport infrastructure in many countries, particularly archipelagic countries such as Indonesia and the Philippines, river deltaic countries like Bangladesh, countries with extensive riverine systems such as the Democratic Republic of the Congo, Nigeria and Senegal, or even a combination of great lakes, rivers and archipelago such as Tanzania, these countries are experiencing a high number of ferry accidents and fatalities over the past two decades and, therefore, considered high-risk countries in the ferry transport sector. International community continuously seeks to enhance safety in the domestic ferry industry. Thus, a scoping study has been conducted on the safety of domestic ferries in these seven high-risk countries. The study utilizes a structured methodology to identify focus areas in the seven countries for enhancing safety in the domestic ferry sector. The analysis involves past domestic ferry accidents, maritime profile, industry demographics and stakeholder matrix, regulatory and governance climate, political landscape, and amenability to change and external intervention. Eventually, the study proposes a conceptual framework with fifteen distinct criteria, identified against five attributes as an aid to the decision-making in a country for considering a safety intervention with a high likelihood of success and a significant positive impact on safety in the domestic ferry sector. Furthermore, current hazards threatening the safety of domestic ferries and their role in the formation of accidents; key stakeholders of domestic ferry sector and their state of play; national regulations related to the safety of domestic ferries and alignment with the IMO model regulations; national political landscape; state’s willingness to facilitate and receive a safety intervention; and public attitude towards safety are presented in the respective countries using globally recognized indices, questionnaire surveys and personal interviews.https://commons.wmu.se/lib_reports/1086/thumbnail.jp
TRACEr-MAR: Technique for the retrospective & predictive analysis of cognitive errors adapted to the maritime domain
This guidebook is the first of a series of WMU Papers in Maritime and Ocean Affairs. It introduces the Human Error Identification technique TRACEr-Mar (Technique for the Retrospective and predictive Analysis of Cognitive Errors adapted to the Maritime Domain).
Modern socio-technical systems had witnessed a complex co-evolution and interaction of both social and technical aspects in the day-to-day reality. However, when an accident occurs in such complex systems, accident causation models always have to simplify the reality and may therefore be limited for fully understanding all the aspects involved in the failing of the maritime socio-technical system involved in that accident. In order to carry out an accident investigation that covers the needs of a particular investigator, different tools exist. A systematic accident analysis requires a full methodological framework consisting of a model to support the focus of the investigation, a related data taxonomy, a methodology for the application of the taxonomy and an outline of the analysis of the findings. This guidebook provides the necessary information for such a framework, TRACEr-Mar, as adapted to the Maritime domain. This framework focusses on human machine interfaces and the related decision making during maritime operations.
The guidebook is addressed to practitioners and researchers determined to apply the TRACEr-Mar technique to maritime accident investigations
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