1,224 research outputs found

    Coupling production networks and regional assets in manufacturing clusters

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    Paradoxically, the ongoing process of globalisation goes hand in hand with a surge of interest in the ‘local’ sources of firm competitiveness. In this paper, we develop a frame of analysis that helps to understand ‘coupling’ of production networks and regional development. Our aim is to reflect on the ‘spatiality’ of different types of networks, and to study the dynamic coupling process between these networks and regional assets. We apply the framework to two case studies – shipbuilding in Turku and machine building in Porto. Our analysis points towards the relevance of regional assets facilitating this coupling process and in strengthening regions as magnets for global production networks, reinforcing the long term sustainability of different types of clusters

    Knowledge Locations in Cities: Emergence and Development Dynamics

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    This thesis studies the development of knowledge locations: area-based initiatives aimed at agglomerating knowledge-intensive activities in a designated area or city district (e.g. technology parks, creative “factories”). It relates the reinvigorated interest (and qualitative change) in knowledge locations with a number of societal evolutions, and develops a theoretical framework to explain their emergence and development. This framework contributes to better ground the study of knowledge locations within the spatial-economic context and dynamics of its host cities and regions. This study also explores the relation between a knowledge location´s features – Specialization, Urban-spatial integration and Management – and their agglomeration outcomes. It shows that there are multiple pathways to growth and agglomeration: no single factor has to be always present to explain it at a certain moment in time. Moreover, the three factors proved relevant but in different ways, and namely to the extent that they contribute to image formation (associated with the identification of a concept) and ecosystem formation (associated with exchange and learning among tenants). Those processes provide two different paths to agglomeration. Their interaction influences the development of a knowledge location over time and, ultimately, the relation between the location and change in its spatial-economic context. The abovementioned phenomena are explored with the support of four European case studies of “themed” knowledge locations, focusing on audiovisual, biotechnology, design and digital media, respectively

    Regional knowledge base and firms´ exploration and exploitation: a multilevel approach

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    How and why do firms interact with and benefit from regionally based sources of knowledge? Although firms increasingly search and source knowledge worldwide and many are inserted in global production and knowledge networks, there is a refreshed interest in the economic geography literature on the interplay between firms´ innovative efforts and regional specific assets. Combining insights from management studies and economic geography, the article presents and explores a theoretical framework linking regionally based knowledge assets with exploration and exploitation efforts of firms, which are increasingly achieved through collaborative networks. The paper argues that the potential of firms to benefit from those localized assets is dependent on the interplay between two moderator effects: firm absorptive capacity, at the firm level, and institutional and organizational infrastructure, at the regional level

    Discriminating among Earth composition models using geo-antineutrinos

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    It has been estimated that the entire Earth generates heat corresponding to about 40 TW (equivalent to 10,000 nuclear power plants) which is considered to originate mainly from the radioactive decay of elements like U, Th and K, deposited in the crust and mantle of the Earth. Radioactivity of these elements produce not only heat but also antineutrinos (called geo-antineutrinos) which can be observed by terrestrial detectors. We investigate the possibility of discriminating among Earth composition models predicting different total radiogenic heat generation, by observing such geo-antineutrinos at Kamioka and Gran Sasso, assuming KamLAND and Borexino (type) detectors, respectively, at these places. By simulating the future geo-antineutrino data as well as reactor antineutrino background contributions, we try to establish to which extent we can discriminate among Earth composition models for given exposures (in units of kt\cdot yr) at these two sites on our planet. We use also information on neutrino mixing parameters coming from solar neutrino data as well as KamLAND reactor antineutrino data, in order to estimate the number of geo-antineutrino induced events.Comment: 24 pages, 10 figures, final version to appear in JHE

    Metabolomic profiling can predict which humans will develop liver dysfunction when deprived of dietary choline

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    Choline is an essential nutrient, and deficiency causes liver and muscle dysfunction. Common genetic variations alter the risk of developing organ dysfunction when choline deficient, probably by causing metabolic inefficiencies that should be detectable even while ingesting a normal choline-adequate diet. We determined whether metabolomic profiling of plasma at baseline could predict whether humans will develop liver dysfunction when deprived of dietary choline. Fifty-three participants were fed a diet containing 550 mg choline/70 kg/d for 10 d and then fed <50 mg choline/70 kg/d for up to 42 d. Participants who developed organ dysfunction on this diet were repleted with a choline-adequate diet for ≥3 d. Plasma samples, obtained at baseline, end of depletion, and end of repletion, were used for targeted and nontargeted metabolomic profiling. Liver fat was assessed using magnetic resonance spectroscopy. Metabolomic profiling and targeted biochemical analyses were highly correlated for the analytes assessed by both procedures. In addition, we report relative concentration changes of other small molecules detected by the nontargeted metabolomic analysis after choline depletion. Finally, we show that metabolomic profiles of participants when they were consuming a control baseline diet could predict whether they would develop liver dysfunction when deprived of dietary choline

    Aspergilosis cerebral causada por Aspergillus fumigatus en paciente con SIDA: primer reporte de caso demostrado por cultivo en Brasil

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    Cerebral aspergillosis is a rare cause of brain expansive lesion in AIDS patients. We report the first culture-proven case of brain abscess due to Aspergillus fumigatus in a Brazilian AIDS patient. The patient, a 26 year-old male with human immunodeficiency virus (HIV) infection and history of pulmonary tuberculosis and cerebral toxoplasmosis, had fever, cough, dyspnea, and two episodes of seizures. The brain computerized tomography (CT) showed a bi-parietal and parasagittal hypodense lesion with peripheral enhancement, and significant mass effect. There was started anti-Toxoplasma treatment. Three weeks later, the patient presented mental confusion, and a new brain CT evidenced increase in the lesion. He underwent brain biopsy, draining 10 mL of purulent material. The direct mycological examination revealed septated and hyaline hyphae. There was started amphotericin B deoxycholate. The culture of the material demonstrated presence of the Aspergillus fumigatus. The following two months, the patient was submitted to three surgeries, with insertion of drainage catheter and administration of amphotericin B intralesional. Three months after hospital admission, his neurological condition suffered discrete changes. However, he died due to intrahospital pneumonia. Brain abscess caused by Aspergillus fumigatus must be considered in the differential diagnosis of the brain expansive lesions in AIDS patients in Brazil.La aspergilosis cerebral es una causa rara de lesión expansiva cerebral en pacientes con SIDA. Presentamos el primer reporte de un absceso cerebral causado por Aspergillus fumigatus en un paciente brasileño con SIDA. El paciente, de 26 años de edad, presentaba antecedentes de infección por el virus de la inmunodeficiencia humana (VIH), tuberculosis pulmonar y toxoplasmosis cerebral. Manifestó fiebre, tos, disnea y dos episódios de convulsiones. La tomografía computadorizada (TC) demostró una lesión hipodensa parasagital y bi-parietal con realce periférico e importante efecto de masa. Se inició tratamiento anti-Toxoplasma. Tres semanas después, el paciente evidenció confusión mental y una nueva TC de cráneo mostró aumento de la lesión. Se realizó biopsia cerebral con drenaje de 10 mL de material purulento. El examen micológico directo reveló hifas hialinas septadas. Se inició anfotericina B deoxicolato. La cultura del material demostró presencia de Aspergillus fumigatus. En los siguientes dos meses el paciente fue sometido a otras tres cirugías, insertándose un catéter de drenaje y administrándose anfotericina B intralesional. Tres meses después de la admisión hospitalaria, la condición neurológica del paciente sufrió discretos cambios. Sin embargo, falleció debido a neumonia intrahospitalaria. Aunque muy raros, los abscesos cerebrales causados por Aspergillus fumigatus deben ser considerados en el diagnóstico diferencial de las lesiones expansivas cerebrales en pacientes con SIDA

    Dietary docosahexaenoic acid supplementation modulates hippocampal development in the pemt-/- mouse

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    The development of fetal brain is influenced by nutrients such as docosahexaenoic acid (DHA, 22:6) and choline. Phosphatidylethanolamine-N-methyltransferase (PEMT) catalyzes the biosynthesis of phosphatidylcholine from phosphatidylethanolamine enriched in DHA and many humans have functional genetic polymorphisms in the PEMT gene. Previously, it was reported that Pemt-/- mice have altered hippocampal development. The present study explores whether abnormal phosphatidylcholine biosynthesis causes altered incorporation of DHA into membranes, thereby influencing brain development, and determines whether supplemental dietary DHA can reverse some of these changes. Pregnant C57BL/6 wild type (WT) and Pemt-/- mice were fed a control diet, or a diet supplemented with 3 g/kg of DHA, from gestational day 11 to 17. Brains from embryonic day 17 fetuses derived from Pemt-/- dams fed the control diet had 25-50% less phospholipid-DHA as compared with WT (p < 0.05). Also, they had 60% more neural progenitor cell proliferation (p < 0.05), 60% more neuronal apoptosis (p < 0.01), and 30% less calretinin expression (p < 0.05; a marker of neuronal differentiation) in the hippocampus compared with WT. The DHA-supplemented diet increased fetal brain Pemt-/- phospholipid-DHA to WT levels, and abrogated the neural progenitor cell proliferation and apoptosis differences. Although this diet did not change proliferation in the WT group, it halved the rate of apoptosis (p < 0.05). In both genotypes, the DHA-supplemented diet increased calretinin expression 2-fold (p < 0.05). These results suggest that the changes in hippocampal development in the Pemt-/- mouse could be mediated by altered DHA incorporation into membrane phospholipids, and that maternal dietary DHA can influence fetal brain development
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