386 research outputs found
Technology neutrality in power transformer regulation and standardisation
The EU’s minimum energy performance standards differentiate power transformers by rated power, rated voltage and technology. The first two are self-evident and performance-based. This article addresses whether technology is pertinent as a differentiator. The main differentiation
is between liquid-filled and drytype transformers. Higher losses are considered acceptable for dry-type transformers to compensate for their ability to fulfil certain requirements. This technology-based concession has resulted from its historical development but hampers innovation and
creates unfair competition. Differentiation to avoid excessively high costs is reasonable, but a better approach would be to formalise the concession for all transformers meeting the same requirements
Assessing the effects of long-term ocean acidification on benthic communities at CO2 seeps
Full version unavailable due to 3rd party copyright restrictions.Ocean acidification has the potential to profoundly affect marine ecosystems before the end of this century, but there are large uncertainties on its effects on temperate benthic communities. Volcanic CO2 seeps provide an opportunity to examine and improve our understanding of community responses to ocean acidification. In this thesis, two Mediterranean CO2 seeps (Methana in Greece and Vulcano in Italy) were used to investigate the responses of macroalgae and their epifaunal communities to increased CO2. Changes in plant-herbivore interactions at elevated CO2, as well as adaptation potential of dominant macroalgae and responses of macroalgae and epifauna to concurrent exposure to elevated CO2 and copper pollution, were also examined. Firstly, I determined that volcanic seeps off Methana (Greece) are suitable for ocean acidification studies as they do not have confounding gradients in temperature, salinity, total alkalinity, nutrients, hydrogen sulphide, heavy metals or wave exposure. Calcifying macroalgae abundance decreased as CO2 increased both at Methana and at Vulcano, while fucoid algae seemed to benefit from elevated pCO2 levels. Seasonality greatly affected macroalgal responses to increasing CO2, according to the annual cycles of dominant species. Epifaunal communities of dominant fucoid algae changed at elevated pCO2 as well, with calcifying invertebrates decreasing and polychaetes increasing near the seeps. Herbivore control of macroalgal biomass did not greatly change at elevated pCO2 levels, as limpets had a minor role in controlling macroalgal biomass off Vulcano (Italy) and sea urchins were replaced by herbivorous fish near seeps off Methana. The two macroalgal species examined for signs of long-term acclimatisation (Cystoseira corniculata (Turner) Zanardini and Jania rubens (Linnaeus) J.V.Lamouroux) to ocean acidification using reciprocal transplants did not appear to have permanently acclimatised to elevated pCO2 levels, but changed their physiology in four to nine months depending on the local environment. Furthermore, when exposed to a 36-hour copper pulse at elevated pCO2 levels both seaweed species accumulated more copper in their tissues compared to those exposed to copper in reference pCO2 conditions, and this resulted in altered epifaunal assemblages on C. corniculata. These observations suggest that benthic communities will significantly change as CO2 levels increase, and that long-term acclimatisation is not likely to play a significant role; this would have profound consequences for benthic ecosystems and the services they provide.This work was funded through a MARES Grant. MARES is a Joint Doctorate programme selected under Erasmus Mundus coordinated by Ghent
University (FPA 2011-0016)
Bridge officers’ operational experiences with electronic chart display and information systems on ships
In this paper, authors suggest an improvement in the electronic chart display and information system handling. Electronic nautical charts provide significant benefits to maritime navigation as a real time navigation system and all updates are important. This paper analyses the electronic chart use experiences on board ships. A questionnaire and survey were used so as to ascertain and corroborate the existing problems with corrections and maintenance of electronic charts on ships, and reliability of the systems was calculated. The survey results have shown that ship’s officers had serious problems with ECDIS systems which were difficult to solve during ship’s operation. A survey was done which showed that a significant percentage of the surveyed bridge officers and captains had problems with ECDIS system operation, such as operation stoppage due to different reasons. They did not always report failures of these systems while having continued to operate ECDIS. The reliability of those systems was also calculated and it resulted 0.916 or 91.6%. Compared to results of previous similar researches done by other scientists, the results of this research show an improvement in the ECDIS handling. It was concluded that a proper action was needed toward finding the solution to the future chart corrections procedure through remote monitoring and maintenance. The study results emphasized that taking action was necessary in the interest of safety protection on ships, with particular attention to be paid to better safety of navigation, of life, and of potential environmental pollution due to this type of information system failures. The results obtained by this study represent a good starting point for future researches in the field
Psychological Reductionism About Persons: A Critical Development
There is a need to distinguish two questions in the philosophy of persons. One of these is the factual question of identity. This is the question of the conditions of personal identity over time. The other is the first person question of survival. This can be expressed as, "Under which circumstances should I consider a person at another time to be my survivor, who I have reason to care about just as much if he were me?" This second question does not presuppose that the survivor is numerically identical with her predecessor and is the question considered in this thesis.
Answering this question requires us to resolve the tension in our concept of a person between, on the one hand, the view of persons as purely physical beings, no more than the sum of their particular parts, bound to the here and now, and on the other hand, as somehow transcendent, beings who exist beyond the here and now.
The conception built upon is that offered by Derek Parfit in Reasons and Persons. Two errors in Parfit's account are explained and amendments suggested. The first is Parfit's explanation of the unity of a mental life over time in terms of connectedness and continuity between individual, independent thoughts, and secondly his account of connectedness and continuity itself. I suggest that psychological connectedness and continuity must be between persons-at-a-time, not individual thoughts, and that a unified mental life over time is not just a product of enough connections, as Parfit argues, but is determined by the kind of connectedness there is
Exploring the geochemistry and shell ultrastructure of bivalves as archives of past ocean acidification events: recent Mytilidae in a natural acidic setting in Ischia (Italy, Mediterranean Sea)
Herbivore diversity improves benthic community resilience to ocean acidification
Ocean acidification is expected to alter a wide range of marine systems, but there is great uncertainty about the outcome because indirect effects are often crucial in ecology. Work at volcanic seeps has shown that major ecological shifts occur due to chronic exposure to acidified seawater. Changes in herbivore densities are often seen and this may interact with direct CO2 effects to determine benthic community structure. Here, an exclusion experiment was used to test effects of herbivory in benthic communities along a pCO2 gradient off Methana (Greece). A manipulative experiment was used to examine how large herbivores affected sublittoral algal communities as seawater carbon dioxide levels increased. Sea urchins and herbivorous fish dramatically reduced macroalgal biomass at background carbon dioxide levels; this effect was not hampered by increased pCO2 despite lower sea urchin densities near the seeps, since herbivorous fish abundances increased concurrently. We found that carbon dioxide levels up to about 2000μatm are unlikely to reduce the role of herbivory in structuring benthic communities if tolerant species are able to replace those that are vulnerable. A shift from sea urchins to fish as main grazers highlights that ocean acidification may cause unexpected responses at the community level, and that maintaining high functional redundancy in marine ecosystems is key to improving their resilience
Marine bivalve geochemistry and shell ultrastructure from modern low pH environments
Abstract. Bivalve shells can provide excellent archives of past environmental change but have not been used to interpret ocean acidification events. We investigated carbon, oxygen and trace element records from different shell layers in the mussels Mytilus galloprovincialis (from the Mediterranean) and M. edulis (from the Wadden Sea) combined with detailed investigations of the shell ultrastructure. Mussels from the harbour of Ischia (Mediterranean, Italy) were transplanted and grown in water with mean pHT 7.3 and mean pHT 8.1 near CO2 vents on the east coast of the island of Ischia. The shells of transplanted mussels were compared with M. edulis collected at pH ~8.2 from Sylt (German Wadden Sea). Most prominently, the shells recorded the shock of transplantation, both in their shell ultrastructure, textural and geochemical record. Shell calcite, precipitated subsequently under acidified seawater responded to the pH gradient by an in part disturbed ultrastructure. Geochemical data from all test sites show a strong metabolic effect that exceeds the influence of the low-pH environment. These field experiments showed that care is needed when interpreting potential ocean acidification signals because various parameters affect shell chemistry and ultrastructure. Besides metabolic processes, seawater pH, factors such as salinity, water temperature, food availability and population density all affect the biogenic carbonate shell archive.</jats:p
Cuando la escuela se transforma en un infierno: Estudio sobre el contenido de las representaciones sociales de la violencia escolar en una escuela secundaria de la Ciudad de México
La violencia en la escuela se ha constituido a lo largo de los últimosaños en México en un tema prioritario en las investigaciones sociales,como asimismo en un tópico destacado en la agenda pública debido al incrementode los casos de inseguridad en el interior de los establecimientoseducativos y en su entorno, además del grado de crueldad que denotan lasacciones violentas y sus consecuencias entre otros motivos, originando unamultiplicidad de estudios que, amparados en marcos teóricos y disciplinariosdiversos, han permitido un análisis del tema desde la perspectiva educativa,social, política, psicológica y de la salud. No obstante, la limitadaliteratura disponible que escruta este problema social desde la mirada de lasrepresentaciones sociales hace que el presente escrito muestre el análisis delas narrativas que los actores de una escuela secundaria periférica de la ciudadde México tienen sobre la violencia escolar con la pretensión de conocerel contenido de las representaciones sociales. Para alcanzar este objetivo setuvo en cuenta un diseño cualitativo en donde se destaca la utilización dela entrevista, la observación y la revisión documental como las técnicas quepermiten la construcción de los datos a partir de los testimonios ofrecidos por los actores escolares de una escuela secundaria y la teoría fundamentadacomo el recurso para la reconstrucción del contenido de las representaciones.La importancia de estudiar este tema radica en la necesidad de hacervisible los significados sociales que el sentido común le atribuye a este fenómenopara entender las prácticas agresivas que se suscitan en el interior dela escuela, además de brindar insumos que ayuden a una revisión de las políticaseducativas que se implementan actualmente para la creación de ambientesescolares basados en el desarrollo de una cultura de la paz. En estesentido, consideramos que el significado de la violencia escolar es construidopor los diversos actores a partir de la conjunción de numerosos factoresde orden subjetivo y social, dando lugar a la construcción de cuatro tipos derepresentaciones que tienden a complementarse y yuxtaponerse en su interpretacióncomo orientadoras de la acción individual y colectiva, originadolos siguientes significados a saber: la violencia escolar como instrumento,la violencia como una forma de relación escolar, la violencia escolar comorasgo identitario y la violencia escolar como efecto de las transformacionessociales
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