581 research outputs found

    Intra-industry trade and labor costs: The smooth adjustment hypothesis

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    We study a situation in which, owing to the exhaustion of non-renewable energy sources, conventional motor vehicles will turn out of use. We consider two scenarios: recycling or dismantling these motor vehicles. M|G|∞ queue system is used to study the process. Through it, we conclude that if the rate of dismantling and recycling of motor vehicles is greater than the rate at which they become idle, the system will tend to get balanced. The model allows also performing a brief study about the recycling or dismantling economic interest.

    Interacting Microsoft Visual Basic Procedures (Macros) and GIS tools in order to access optimal location and maximum use of railways and railway infrastructures

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    Some parts of the Portuguese railway infrastructure have been neglected through time: Rural lines have been abandoned, investment in new infrastructure is sometimes delayed, and marketing strategies to keep or attract more users have not been pursued. Simultaneously, problems with urban congestion, pollution and mobility for the young, the elderly, the poor, and the handicapped are putting forward the discussion about new or more sustainable modes of transportation. Common sense of public officials, other lobbying groups, and the locals demand new, trendy train lines. And while some axes may have the potential to justify rail lines, others seem to lack population or funding to be enabled. One major problem in order to evaluate the worthiness of these rail projects has been the fact that very often the studies of travel demand and physical implantation are done separately. Travel demand analysis is done based on the four-step model (trip generation, distribution, modal split, and network assignment) using survey data and the network system, using a relatively wide zoning. The importance of interacting with other, finer, information (i.e. slope, density of population, environmental sensitivity, or other socio-economic and land use information) with the development of the travel analysis demand will enhance the analysis/results and increase the chance of proposing lines that are both optimal in location and will have the maximum use by the citizens. Off the shelf software is still unable to perform this kind of operations. Some perform the analysis using existing networks, and no information on the land is available besides the zoning system, other software propose lines accordingly to land slopes, but no trip information is included. GIS packages have the capacity to include the land information and some have some transportation analysis, but are lacking computation capabilities and algorithms to perform analysis similar to off-the-shelf transportation software. In order to develop this kind of integrated analysis it is important to have a good knowledge of the algorithms and analysis required by transportation and of the tools/opportunities offered by the GIS packages. This paper presents a methodology that integrates the transportation algorithms with the GIS functionalities, using excel macro-language. The result is an interaction of both travel demand analysis and site selection. The characteristics of the place constrain the travel demand analysis, but on its own the travel demand analysis define not only the buffer of the train line, but systematically enhance the shape of the line and the location of the stops each time the results of a phase of the travel demand analysis is outputted. This paper offers guidelines for those developing travel demand analysis including some site selection criteria, and it can be a starting point for those of whom intend to develop further application of in the GIS fields.

    Redetermination at 180 K of a layered lanthanide–organic framework

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    The asymmetric unit of the title compound, poly[(μ4-{[bis­(hydrogen phospho­natometh­yl)aza­nium­yl]meth­yl}phospho­nato)lanthanum(III)], [La(C3H9NO9P3)]n, comprises an La3+ center and a H3nmp3− anion (where H3nmp3− is a residue of partially deprotonated nitrilo­tris­(methyl­ene­phospho­nic acid), namely {[bis­(hydrogen phospho­natometh­yl)aza­nium­yl]meth­yl}­phos­pho­nate). This study concerns a structural redetermination using single-crystal X-ray diffraction data, collected at the low temperature of 180 K, of a recently investigated material whose structural details have been proposed from powder X-ray diffraction studies [Silva et al. (2011 ▶). J. Am. Chem. Soc. 133, 15120–15138]. The main difference between the two models rests on the position of the H atoms. While two H atoms were modeled as attached to the same phospho­nate group in the powder determination, in the current model, the same H atoms are instead distributed among two of these groups. The sample studied was an inversion twin

    Plataforma de monitorização e suporte à decisão de doentes críticos

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    A situação complexa dos doentes críticos e a quantidade de dados disponíveis dificultam a obtenção de conhecimento profícuo para a decisão. Acrescendo o facto de nas Unidades de Cuidados Intensivos (UCI) ainda existir um elevado número de dados em papel, o decisor não consegue interpretar corretamente e em tempo útil toda a informação adquirida. Neste contexto, o fator humano pode provocar erros no processo de tomada de decisão (PTD), uma vez que, normalmente, não há tempo suficiente para analisar corretamente a situação clínica do doente. Para facilitar a aquisição de conhecimento e suportar o PTD por parte dos profissionais da UCI, foi desenvolvida uma plataforma global que, de entre as várias funcionalidades, permite um acompanhamento do doente e a previsão de eventos futuros de uma forma contínua e em tempo real, apresentando novos conhecimentos que podem contribuir de forma significativa para a melhoria da situação clínica de um doente.The complex situation of critical patients and the amount of data available in Intensive Care Units (ICU) makes difficult to obtain useful knowledge to the decision. Adding the fact that in ICU there is a large number of data on paper the decision maker cannot interpret correctly and in short time all the information acquired. In this context the human factor can cause errors in decision-making process (DMP), because normally the intensivist does not have enough time to properly analyse the clinical condition of the patient. To facilitate the acquisition of knowledge and support the ICU decision process by their professionals, a global platform was developed. Among the various features, this platform allows patient monitoring and forecasting future events continuously and in real time, presenting whenever is possible new knowledge which can contribute significantly to the improvement of the clinical status of a patient

    The role of shell crossing on the existence and stability of trapped matter shells in spherical inhomogeneous \Lambda-CDM models

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    We analyse the dynamics of trapped matter shells in spherically symmetric inhomogeneous \Lambda-CDM models. The investigation uses a Generalised Lema\^itre-Tolman-Bondi description with initial conditions subject to the constraints of having spatially asymptotic cosmological expansion, initial Hubble-type flow and a regular initial density distribution. We discuss the effects of shell crossing and use a qualitative description of the local trapped matter shells to explore global properties of the models. Once shell crossing occurs, we find a splitting of the global shells separating expansion from collapse into, at most, two global shells: an inner and an outer limit trapped matter shell. In the case of expanding models, the outer limit trapped matter shell necessarily exists. We also study the role of shear in this process, compare our analysis with the Newtonian framework and give concrete examples using density profile models of structure formation in cosmology.Comment: 17pp 12fig

    N-acetylgalactosamine 4-sulfate 6-O-sulfotransferase expression during early mouse embryonic development

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    N-acetylgalactosamine 4-sulfate 6-O-sulfotransferase (GalNAc4S-6ST) is an enzyme which is known to help build up the GlcA beta 1-3GalNAc(4,6-bisSO(4)) unit of chondroitin sulfate E (CSE). This enzymatic activity has been reported in squid cartilage and in human serum, but has never been reported as an enzyme required during early mouse development. On the other hand, CSE has been shown to bind with strong affinity to Midkine (MK). The latter is a heparin-binding growth factor which has been found to play important regulatory roles in differentiation and morphogenesis during mouse embryonic development. We have analyzed the expression pattern of the GalNAc4S-6ST gene during early mouse embryonic development by whole mount in situ hybridization. The results show that GalNAc4S-6ST is differentially expressed in the anterior visceral ectoderm at stage E5.5 and later becomes restricted to the embryonic endoderm, especially in the prospective midgut region. During the turning process, expression of GalNAc4S-6ST gene is detected in the forebrain, branchial arches, across the gut tube (hindgut, midgut and foregut diverticulum), in the vitelline veins and artery and in the splanchnopleure layer. These results open the possibility of a role for GalNAc4S-6ST during early mouse development

    A queue model for recycling and. dismantling motor vehicles

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    We study a situation in which, owing to the exhaustion of non-renewable energy sources, conventional motor vehicles will turn out of use. We consider two scenarios: recycling or dismantling these motor vehicles. M|G|°° queue system is used to study the process. Through it, we conclude that if the rate of dismantling and recycling of motor vehicles is greater than the rate at which they become idle, the system will tend to get balanced. The model allows also performing a brief study about the recycling or dismantling economic interest
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