1,007 research outputs found

    Internal Migration and Regional Population Dynamics in Europe: Portugal Case Study

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    Report prepared for the Council of Europe (Directorate of Social and Economic Affairs, Population and Migration Division) and for European Commission (Directorate General V, Employment, Industrial Relations and Social Affairs, Unit E1, Analysis and Research on the Social Situation). This paper reports on internal migration and regional population dynamics in Portugal. It examines internal migration patterns and trends in two years, 1981 and 1991, and compares them. Portugal is a country that has reached a population plateau and is currently experiencing very little overall population growth. In 1981 its population was 9.83 millions, only 9.87 millions in 1991 and 9.96 millions in 1997. During the 1980s natural increase steadily diminished and in the 1990s it has virtually ceased. International migration was predominantly negative in balance during the period between the mid 1980s and early 1990s, but has moved into small positive gains in the last few years. When population changes for the 1981-91 period are examined, the picture is broadly of gains in the major urban-centred regions of Norte and Lisboa Vale Tejo, and in the resort industry region of the Algarve. In the more peripheral regions, population decreases occurred, that is in the Centro, Alentejo and Açores regions with Madeira being roughly in balance. Natural increase was strong in the Norte and island regions and compensated for net out-migration, while elsewhere it was weak. All Portuguese NUTS 2 regions except the Algarve lost through migration, with emigration dominating any counter-flows due to internal migration. However, the strong influence of internal migration is apparent when the components of population change at concelhos scale are analysed. The largest cities, Lisboa and Porto, lose population in the 1981-91 period, particularly the capital, and part of the population losses represent migration to surrounding concelhos in the Outer parts of the city regions. Most of the rest of Grande Porto outside of the main city gains population through migration. Around Lisboa these suburban migration gains were experienced by the margins of Lisboa itself, the northern suburbs along the north bank of the Tagus and in a majority of the concelhos of Península Setúbal across the Tagus estuary from Lisboa, namely the southern suburbs linked to the city by two major road bridges. The Censuses of 1981 and 1991, which count migrants in the circa 15-month period before the census date (14½ and 15½ months in the two censuses), provide a picture of how internal migration affects people in different life stages. The all ages pattern of migration in 1979-81 is one of greatest losses from interior and eastern regions (NUTS 3 scale), lesser losses from remoter coastal regions and gains to the urban regions centred on Porto, Lisboa and the Algarve resorts. However, the centres of the Porto and Lisboa regions lose migrants, confirming the earlier interpretation of the components of population change. The situation in 1989-91 was similar but there were fewer regions with great migration losses, more regions with moderate losses and gains around the main urban nodes and the southern tourist coast. This general pattern of redistribution characterises the childhood and family ages (0-14, 25-44) and is intensified in terms of losses from the large cities and suburban gains in the 45-64 age group. Young persons, however, behave differently. In 1979-81 most of the regions of the country lost internal migrants in the 15-24 age group, while Lisboa, Porto and the Algarve experienced substantial migration gains. So, while the family ages showed a de-concentration pattern, the ages at which young adults start independent life careers showed centralising tendencies. The spatial pattern was broadly similar in 1989-91 but more interior regions posted migration gains. The retirement ages, 65 to 74, showed similar centralisation for the female population but not for the male. This age group was the only one that exhibited strong gender differences in the pattern of migration and considerable changes between 1979-81 and 1989-91. Whereas in the former period, the pattern was very much one of interior loss and coastal and urban region gain, in 1989-91, losses from the interior were relatively lower and moderate gains more widespread. At the oldest ages of 75 years or more the strong pattern of interior loss and coastal gain reasserted itself. Portuguese population dynamics thus exhibit some rural depopulation (mainly of the young and the very old), some urbanisation (migration to more densely settled regions around the biggest cities), some suburbanisation (de-concentration within the largest urban regions) and some regional flows to resource exploiting regions (sun and sea in the resort coast of the Algarve). Population gains in the 1981-91 decade also occurred in several coastal and interior small towns and medium-sized urban centres outside of Lisboa and Porto. This reveals that urbanisation was not just a metropolitan phenomenon but was a widespread process. Note that when considering whether the Portuguese population is centralising or decentralising, attention must be paid to the scale of migration observed. So, for example, population may be moving into the metropolitan regions of Lisboa and Porto and therefore centralising, but within those regions the population may be shifting from city to suburbs and to outer parts of the city region, and therefore decentralising. This nested system of flows may be obscured if attention is focused exclusively on total net migration

    Imaging 3D seismic velocity along the seismogenic zone of Algarve region (southern Portugal)

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    The present seismic tomographic study is focused around Algarve region, in South of Portugal. To locate the seismic events and find the local velocity structure of epicentral area, the P and S arrival times at 38 stations are used. The data used in this study were obtained during the Algarve campaign which worked from January/2006 to July/2007. The preliminary estimate of origin times and hypocentral coordinates are determined by the Hy- poinverse program. Linearized inversion procedure was applied to comprise the following two steps: 1) finding the minimum 1D velocity model using Velest and 2) simultaneous relocation of hypocenters and determination of local velocity structure. The velocity model we have reached is a 10 layer model which gave the lowest RMS, after several runnings of eight different velocity models that we used “a priori”. The model parameterization assumes a continuous velocity field between 4.5 km/s and 7.0 km/s until 30 km depth. The earth structure is represented in 3D by velocity at discrete points, and velocity at any intervening point is determined by linear interpolation among the surrounding eight grid points. A preliminary analysis of the resolution capabilities of the dataset, based on the Derivative Weight Sum (DWS) distribution, shows that the velocity structure is better resolved in the West part of the region between the surface to15 km. The resulting tomographic image has a prominent low-velocity anomaly that shows a maximum decrease in P-wave velocity in the first 12 kms in the studied region. We also identified the occurrence of local seismic events of reduced magnitude not catalogued, in the neighbourhood of Almodôvar (low Alentejo). The spatial distribution of epicentres defines a NE-SW direction that coincides with the strike of the mapped geological faults of the region and issued from photo-interpretation. Is still expectable to refine the seismicity of the region of Almodôvar and establish more rigorously its role in the seismotectonic picture of the region. This work is expected to produce a more detailed knowledge of the structure of the crust over the region of Algarve, being able to identify seismogenic zones, potentially generators of significant seismic events and also the identification of zones of active faults

    Non-Gaussianity after many-field reheating

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    International audienceWe numerically investigate reheating after quadratic inflation with up to 65 fields, focusing on the production of non-Gaussianity. We consider several sets of initial conditions, masses, and decay rates. As expected, we find that the reheating phase can have a significant effect on the non-Gaussian signal, but that for this number of fields a detectable level of non-Gaussianity requires the initial conditions, mass range, and decay rates to be ordered in a particular way. We speculate on whether this might change in the N-flation limit

    Attractor behaviour in multifield inflation

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    We study multifield inflation in scenarios where the fields are coupled non-minimally to gravity via ξI(ϕI)ngμνRμν\xi_I(\phi^I)^n g^{\mu\nu}R_{\mu\nu}, where ξI\xi_I are coupling constants, ϕI\phi^I the fields driving inflation, gμνg_{\mu\nu} the space-time metric, RμνR_{\mu\nu} the Ricci tensor, and n>0n>0. We consider the so-called α\alpha-attractor models in two formulations of gravity: in the usual metric case where Rμν=Rμν(gμν)R_{\mu\nu}=R_{\mu\nu}(g_{\mu\nu}), and in the Palatini formulation where RμνR_{\mu\nu} is an independent variable. As the main result, we show that, regardless of the underlying theory of gravity, the field-space curvature in the Einstein frame has no influence on the inflationary dynamics at the limit of large ξI\xi_I, and one effectively retains the single-field case. However, the gravity formulation does play an important role: in the metric case the result means that multifield models approach the single-field α\alpha-attractor limit, whereas in the Palatini case the attractor behaviour is lost also in the case of multifield inflation. We discuss what this means for distinguishing between different models of inflation.Comment: 20 pages, 6 figures. Typos corrected and references added. This is an author-created, un-copyedited version of an article published in JCAP. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://iopscience.iop.org/article/10.1088/1475-7516/2018/06/032/pd

    Family business succession: Analysis of the drivers of success based on entrepreneurship theory

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    This study explores family business succession. In this study, succession is compared to the concept of opportunity versus necessity entrepreneurship. The motivations of successors when they enter the succession process are examined to identify different conditions for family business success and sustainability. The influence of context is also considered. This study is based on multilevel research and a multidisciplinary perspective. Fuzzyset qualitative comparative analysis (fsQCA) is applied to a sample of 383 observations from 6 countries (Portugal, Italy, Greece, Cyprus, North Macedonia, and Bulgaria) spanning 2 regions: southern European Mediterranean countries (Portugal, Italy, Greece, and Cyprus) and southern Slavic countries (North Macedonia and Bulgaria). The interplay between personal characteristics of the successor, organizational characteristics of the family business, and context produces different patterns that lead to different outcomes in the succession processes of family businesses. The results are important to strengthen family business theory and identify the conditions that best promote the future growth and sustainability of family businesses. The results are also important to promote country-specific public policies that may create better conditions for successors in family businesses to succeed.info:eu-repo/semantics/publishedVersio

    Carcinoma da Tiróide em Crianças e Jovens Adultos: Revisão Retrospectiva de 19 Casos

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    Introduction: Thyroid carcinoma is rare in children and young adults. Most of management guidelines are based in data from adult population. Several controversies remain regarding the aggressiveness of clinical presentation and therapeutic approach. Objective: To evaluate all differentiated thyroid carcinoma patients with less than 20 years-old at presentation reflecting the experience of our unit in relation to diagnosis, treatment and follow-up of this clinical entity. Material and Methods: This is a retrospective review of clinical records of all children and young adults followed at Oncology Consultation of Department of Endocrinology of Centro Hospitalar e Universitário de Coimbra between 1996 and 2012. Results: Nineteen patients with mean age of 16 years old were followed, 13 girls and 6 boys. None of the patients had previous neck irradiation. A palpable cervical mass was the presenting complaint in 84.6%. FNA was performed in 15 patients and was diagnostic or suspicious of malignancy in 71.4%. Total thyroidectomy was performed in 18 cases (94.7%). Papillary carcinoma was identified in all. Vascular invasion and multicentry occurred in 21.1%. Mean tumor size was 2.5cm. Cervical lymph node involvement was diagnosed in 31.6% and distant metastases in 5.2%. The majority of patients (18 in 19) were classified as stage I disease. All patients received thyroxine suppressive therapy and postoperative radioiodine ablation was given to 84.2% (mean dose 85.7mCi). During mean follow-up of almost 6 years, 16 patients remain disease free. Conclusion: In our series, cervical lymph node and distant metastases rates were similar to that found in adult population. Overall prognosis was very good

    The identification of multiple thrombophilic risk factors in an infant with cerebrovascular accident

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    We found 1 article: Rev Neurol. 2005 Apr 16-30;40(8):479-81. [The identification of multiple thrombophilic risk factors in an infant with cerebrovascular accident] [Article in Spanish] Neves J, Costa E, Branca R, Carrilho I, Barbot J, Barbot C. Servicio de Hematología, Hospital de Crianças Maria Pia, 4050-111 Porto, Portugal. Abstract INTRODUCTION: Neonatal stroke (NNS) incidence appears to be increasing over the last years. This is believed to be a consequence of diagnostic accuracy rather than a real amplification of this entity. Nowadays, NNS incidence is estimated to be 1:4000 full newborns. CASE REPORT: Child with left middle cerebral artery territory infarction in which several thromboembolic risk factors were documented both in the child (neonatal sepsis and factor V Leiden) and his mother (lupus anticoagulant, pre-eclampsy and factor V Leiden). CONCLUSIONS: This case supports the increasing evidence in recent reports that association of multiple prothrombotic risk factors (maternal and foetal) is present in NNS genesis. This way the authors agree that wide prothrombotic study may be of crucial interest in identifying subjacent thrombophilic disease, even when an exogenous risk factor is present. PMID: 15861329 [PubMed - indexed for MEDLINE

    Unfolding the dynamical structure of Lisbon’s public space: space syntax and micromobility data

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    Space Syntax and the theory of natural movement demonstrated that spatial mor- phology is a primary factor influencing movement. This paper investigates to what extent spatial morphology at different scales (node, community and global network) influences the use of public space by micromobility. An axial map and corresponding network for Lisbon’s walkable and open public space, and data from e-scooters parking locations, is used as case study. Relevant metrics and their correlations (intelligibility, accessibility, permeability and local dimension) for the quantitative characterization of spatial morphology properties are described and computed for Lisbon’s axial map. Communities are identified based on the network topological structure in order to investigate how these properties are affected at different scales in the case study. The resulting axial line clustering is compared via the variation of information metric with the clustering obtained from e-scooters’ proximity. The results obtained enable to con- clude that the space syntax properties are scale dependent in Lisbon’s pedestrian net- work. On the other hand both the correlation between these properties, the number of scooters and the variation of information between clusters indicate that the spatial morphology is not the only factor influencing micromobility. Through the compara- tive analysis between the main properties of the public space network of Lisbon and data collected from e-scooters locations in a timeframe, centrality becomes a dynamic concept, relying not only on the static topological properties of the urban network, but also on other quantitative and qualitative factors, since the flows’ operating on the network will operate several transformations on the spatial network properties through time, uncovering spatiotemporal dynamics.info:eu-repo/semantics/publishedVersio

    FINITE STRAIN ANALYSIS OF LIMESTONE/BASALTIC MAGMA INTERACTION AND FRACTURE: LOW ORDER MIXED TETRAHEDRON AND REMESHING

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    In this investigation, we use a recent constitutive framework and remising technique for tetrahedra to analyse the pressure-driven crack propagation of limestone intruded by basaltic magma. Limestone is represented by an least-plastic capped Drucker-Prager model with an hypo elastic term in order to account for inelastic effects from plastic signature. Kinematic hardening is considered for limestone, whereas magma is modelled by means of a compressible Bingham fluid. Classical limit surfaces of the capped model are used to initiate the crack events in the limestone. Propagation is performed by a local remising technique with mesh smoothing for untracked elements. Arnold's MINI element is used to avoid locking in the quasi-incompressible case. Verification (for limestone) examples and a crack propagation example in 3D are performed. A mesh convergence study is performed, exhibiting very promising results
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