997 resultados para 189-1170A
Resumo:
Tutkimuksessa tarkastellaan dementiakuolleisuutta sekä siihen vaikuttavia sosiaalisia tekijöitä. Dementia on oireyhtymä, jota pääasiassa sairastavat yli 65 -vuotiaat henkilöt. Väestön ikääntyessä sekä elinajanodotteen kasvaessa on odotettavissa, että dementiaa sairastavien määrä tulee kasvamaan merkittävästi lähivuosina. On viitteitä siitä, että dementiaan sairastumisen riskiin vaikuttavat erilaiset sosiaaliset tekijät kuten koulutus, mutta varsinkin dementiakuolleisuudesta tiedetään vähän. Tutkielman aineistona käytettiin Tilastokeskuksen muodostamaa Elinolot ja kuolinsyyt -rekisteriaineistoa, joka koostuu väestölaskentatiedoista sekä työssäkäyntitilaston pitkittäisaineistosta, johon on liitetty kuolinsyytietoja. Peruskuolinsyyn lisäksi aineistossa oli tieto korkeintaan kolmesta myötävaikuttavasta syystä. Dementiakuolleisuuden on esitetty aliarvioituvan peruskuolinsyynä, joten dementiakuolleisuuden määrittelyssä käytettiin myös tietoa myötävaikuttavista syistä. Rajausten jälkeen aineistossa on 317 944 henkilöä, joista 128 562 on miehiä ja 189 382 naisia. Pääanalyysimenetelmänä on käytetty elinaikamalleihin kuuluvaa Coxin regressiota. Dementiakuolleisuudessa oli vaihtelua kaikkien tutkimuksessa käytettyjen muuttujien, eli koulutuksen, sosiaaliluokan, tulojen, siviilisäädyn sekä perhemuodon mukaan. Koulutuksen vaikutus välittyi osin ammattiasemaan perustuvan sosiaaliluokan kautta. Suurimpia ryhmien väliset suhteelliset erot olivat nuoremmissa ikäryhmissä sekä sosiaaliluokan ja siviilisäädyn kohdalla. Eronneilla ja naimattomilla oli selvästi kohonnut riski suhteessa naimisissa oleviin. Myös työntekijöillä havaittiin kohonnut riski suhteessa ylempiin toimihenkilöihin. Siviilisääty vaikutti olevan merkittävä tekijä siinä mielessä, että koulutuksen, sosiaaliluokan ja tulojen tuominen malliin ei juuri vaikuttanut siviilisäätyryhmien välillä havaittuun vaihteluun. Dementiakuolleisuudessa havaitut ryhmien väliset suhteelliset erot olivat hieman pienempiä kuin muissa syissä, mutta kuitenkin hyvin samaa suuruusluokkaa. Tulosten perusteella on identifioitavissa tekijöitä, jotka suojaavat dementialta. Erityisesti avioliitto, korkea koulutus sekä ylemmät toimihenkilöammatit vaikuttavat olevan dementialta suojaavia tekijöitä. Avioliiton suojaavan vaikutuksen voidaan tulkita liittyvän sosiaaliseen kanssakäymiseen sekä puolison tukeen ja läsnäoloon. Korkea koulutus sekä toimihenkilöammatit indikoivat virikkeellisempää työympäristöä, mutta niiden vaikutus voi myös kulkea ylipäänsä aktiivisemman ja kognitiivisesti virikkeellisemmän elämäntavan kautta. Aktiivisen ja kognitiivisesti haastavan elämäntavan on esitetty suojaavan dementiaan sairastumiselta. Tuloksia voidaan tulkita elämänkaarinäkökulman kautta. Jo nuoruudessa vaikuttavilla tekijöillä, kuten koulutuksella, on vaikutusta. Tämän lisäksi elämänkaaren aikana myöhemmin vaikuttavat tekijät ovat merkityksellisiä. Näiden tekijöiden on esitetty vaikuttavan aivojen hermoverkostoon ja -yhteyksiin ja luovan kognitiivista reserviä, minkä on esitetty ehkäisevän tai lykkäävän dementiaan sairastumista.
Resumo:
This paper is concerned with a study of an operator split scheme and unsplit scheme for the computation of adiabatic freely propagating one-dimensional premixed flames. The study uses unsteady method for both split and unsplit schemes employing implicit chemistry and explicit diffusion, a combination which is stable and convergent. Solution scheme is not sensitive to the initial starting estimate and provides steady state even with straight line profiles (far from steady state) in small number of time steps. Two systems H2-Air and H2-NO (involving complex nitrogen chemistry) are considered in presentinvestigation. Careful comparison shows that the operator split approach is slightly superior than the unsplit when chemistry becomes complex. Comparison of computational times with those of existing steady and unsteady methods seems to suggest that the method employing implicit-explicit algorithm is very efficient and robust.
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A broad numerical survey of relativistic rotating neutron star structures was compiled using an exhaustive list of presently available equation of state models for neutron star matter. The structure parameters (spherical deformations in mass and radii, the moment of inertia and quadrupole moment, oblateness, and free precession) are calculated using the formalism proposed by Hartle and Thorne (1968). The results are discussed in relation to the relevant observational information. Binary pulsar data and X-ray burst sources provide information on the bulk properties of neutron stars, enabling the derivation of constraints that can be put on the structure of neutron stars and equation of state models.
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The terminal solid solubilities of the periclase (MgO-rich) and zincite (ZnO-rich) solid solutions in the MgO---ZnO system have been determined by measuring the activity of MgO using a solid-state galvanic cell of the type 02(g), Pt/MgO, MgF2//MgF2//{χMgO+(1-χ)ZnO}(s, sln), MgF2/Pt, O2(g) in the temperature range 900–1050°C. The ZnO activity was calculated by graphical Gibbs-Duhem integration. The activity-composition plots of both components exhibit a strong positive deviation from ideality and are characterised by a miscibility gap. The terminal solid solubilities of the periclase and zincite solid solutions obtained from the activity-composition plots are found to be in reasonable agreement with those reported in the literature.
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The formation of anomalous indentations, with two opposite faces describing a pin-cushion effect and the other two faces normal, in long elongated grains of an extruded Mg-2Al-1Zn alloy is reported. Subsurface microstructural observations combined with Schmid factor calculations suggest that extension twinning accompanied by basal slip are the reasons for these. Johnson's expanding cavity model is invoked for further substantiation. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Resumo:
Polystyrene/multiwall carbon nanotube composite films are prepared with loading up to 7 weight percent (wt%) of multiwall carbon nanotubes by solution processing and casting technique. In the formation of these composite films, iron filled carbon nanotubes with high aspect ratio (similar to 4000) were used. Scanning electron microscopy study shows that the nanotubes are uniformly dispersed within the polymer matrix. At high magnification, bending of carbon nanotubes is noticed which can be attributed to their elastic properties. The electrical conductivity measurements show that the percolation threshold is rather low at 0.21 wt%. Hysteresis loop measurements on the bulk multiwall carbon nanotube and composite samples are done at 10, 150 and 300 K and the coercivity values are found to be largest at all the temperatures, for 1 wt% composite sample. (C) 2010 Elsevier B.V. All rights reserved.
Resumo:
The problem of pumping an aquifer in an aquifer-water table aquitard system is considered, accounting for the elastic properties of both the aquifer and the aquitard, the gravity drainage in the aquitard and treating the water table as an unknown boundary. The coupled partial differential equations are nondimensionalised, yielding three principal parameters governing the problem. The numerical solution of these equations is obtained for a wide range of parameter values. Type curves are generated and their use is illustrated through a field application.
Resumo:
Right as an Argument. Leo Mechelin and the Finnish Question 1886-1912 At the turn of the 20th century the Finnish Question rose up as a political and juridical issue at the international arena. The vaguely précised position of Finland in the Russian empire led to diverse conclusions concerning the correctness of the February manifesto of 1899. It was predominantly among a European elite of politicians, cultural workers and academics the issue rose some interest. Finns were active making propaganda for their cause, and they put an emphasis on the claim that the right was on the Finnish side. In the study Elisabeth Stubb compare the Finnish, Russian and European statements about the Finnish Question and analyse their use of right as an argument. The Finnish Question offers at the same time a case study of a national entity which possesses a political sphere of life but is not fully independent, and its possibilities to drive its interests in an international context. Leo Mechelin (1839-1914), the leader of the Finnish propaganda organization abroad, is used as a point of departure. The biographical stance is formed into a triangle, where Leo Mechelin, the idea of right and the Finnish Question abroad are the three cornerstones. The treatment of one cornerstone sheds a ligth on the two others. The metaphor of triangulation also worked as a method to reach "a third stance" in a scinetific and political issue that usually is polarised into two opposite alternatives. An adherence to a strict legal right could not in the end offer a complete, unquestionable and satisfactory solution to the Finnsih Question, it was dependent on "the right of state wisdom and sound insight". The Finnish propaganda abroad used almost completely alternative ways of making politics. The propaganda did not have a decisive effect on countries' official politics, but gained unofficial support, especially in the public opinion and in academic statements. Mechelin claimed that the political field was dependent on public opinion and scientific research. Together with the official politics these two fields formed a triangle that shared the task of balancing the political arena and preventing it from making unwise decisions of taking an unjust turn. The international sphere worked as a balancing part in the Finnish Question. Mechelin tried by claiming the status of state for Finland's part to secure the country a place at the official international arena. At the same time, and especially when the claim was not fully adopted, he emphasised, and in a European context worked for, that right would become the guiding light not only for international relations, but also for the policy making in the inner life of the state.
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A review of the research work that has been carried out thus far relating the casting and heat treatment variables to the structure and mechanical properties of Al–7Si–Mg (wt-%) is presented here. Although specifications recommend a wide range of magnesium contents and a fairly high content of iron, a narrow range of magnesium contents, closer to either the upper or lower specified limits depending on the properties desired, and a low iron content will have to be maintained to obtain optimum and consistent mechanical properties. A few studies have revealed that the modification of eutectic silicon slightly increases ductility and fracture toughness and also that the effect of modification is predominant at low iron content. Generally, higher solidification rates give superior mechanical properties. Delayed aging (the time elapsed between quenching and artificial aging during precipitation hardening) severely affects the strength of the alloy. The mechanism of delayed aging can be explained on the basis of Pashley's kinetic model. It has been reported that certain trace additions (cadmium, indium, tin, etc.) neutralise the detrimental effect of delayed aging. In particular, it should be noted that delayed aging is not mentioned in any of the specifications. With reference to the mechanism by which trace additions neutralise the detrimental effect of delayed aging, various hypotheses have been postulated, of which impurity–vacancy interaction appears to be the most widely accepted.
Resumo:
Molecular dynamics calculations are reported for Xe in sodium Y zeolite with varying strengths of sorbate-zeolite dispersion interaction. In the absence of any dispersion interaction between the sorbate and the zeolite, the presence of the zeolite has a purely geometrical role. Increase in the strength of the sorbate-zeolite interaction increases the monomer population and decreases the population of dimers and higher sized clusters. The lifetime of the monomers as well as dimers increases with the strength of the dispersion interaction. The observed variations in the lifetime and the population of the different sized clusters is explained in terms of the changes in the potential energy surface caused by the increase in the strength of the dispersion interaction.
Resumo:
he effect of pressure on the conductivity of AgI-Ag2 O-MoO3 glasses has been reexamined. A conductivity maximum is observed around 0.7 GPa. No variation of the sample temperature is noted under pressure. The results are found to agree well with the cluster-tissue model.
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The direct intratesticular injection of [P-32]phosphate resulted in 4-9 times more labelling of rat testis proteins compared to the conventional method of in vitro incubation. Moreover this is a simple technique requiring minimum (7-10 times less) radioactive phosphate and is less hazardous.