39 resultados para highly siderophile elements


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This study provides insights into the composition and origin of ferropicrite dikes (FeOtot = 13 17 wt. %; MgO = 13 19 wt. %) and associated meimechite, picrite, picrobasalt, and basalt dikes found at Vestfjella, western Dronning Maud Land, Antarctica. The dikes crosscut Jurassic Karoo continental flood basalts (CFB) that were emplaced during the early stages of the breakup of the Gondwana supercontinent ~180 Ma ago. Selected samples (31 overall from at least eleven dikes) were analyzed for their mineral chemical, major element, trace element, and Sr, Nd, Pb, and Os isotopic compositions. The studied samples can be divided into two geochemically distinct types: (1) The depleted type (24 samples from at least nine dikes) is relatively depleted in the most incompatible elements and exhibits isotopic characteristics (e.g., initial εNd of +4.8 to +8.3 and initial 187Os/188Os of 0.1256 0.1277 at 180 Ma) similar to those of mid-ocean ridge basalts (MORB); (2) The enriched type (7 samples from at least two dikes) exhibits relatively enriched incompatible element and isotopic characteristics (e.g., initial εNd of +1.8 to +3.6 and initial 187Os/188Os of 0.1401 0.1425 at 180 Ma) similar to those of oceanic island basalts. Both magma types have escaped significant contamination by the continental crust. The depleted type is related to the main phase of Karoo magmatism and originated as highly magnesian (MgO up to 25 wt. %) partial melts at high temperatures (mantle potential temperature >1600 °C) and pressures (~5 6 GPa) from a sublithospheric, water-bearing, depleted peridotite mantle source. The enriched type sampled pyroxene-bearing heterogeneities that can be traced down to either recycled oceanic crust or melt-metasomatized portions of the sublithospheric or lithospheric mantle. The source of the depleted type represents a sublithospheric end-member source for many Karoo lavas and has subsequently been sampled by the MORBs of the Indian Ocean. These observations, together with the purported high temperatures, indicate that the Karoo CFBs were formed in an extensive melting episode caused mainly by internal heating of the upper mantle beneath the Gondwana supercontinent. My research supports the view that ferropicritic melts can be generated in several ways: the relative Fe-enrichment of mantle partial melts is most readily achieved by (1) relatively low degree of partial melting, (2) high pressure of partial melting, and (3) melting of enriched source components (e.g., pyroxenite and metasomatized peridotite). Ferropicritic whole-rock compositions could also result from accumulation, secondary alteration, and fractional crystallization, however, and caution is required when addressing the parental magma composition.

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The multifaceted passive present participle in Finnish This study investigates the uses of the passive present participle in Finnish. The participle occurs in a variety of syntactic environments and exhibits a rich polysemy. Former descriptions have treated it as a mainly modal element, but it has several non-modal uses as well. The present study provides an overview of its uses and meanings, with the main focus on the factors which trigger the modal reading. In addition, the study contains two case studies on modal periphrastic constructions consisting of the verb 'to be' and the present passive participle, the Obligation construction, e.g., on men-tä-vä [is go-pass-ptc], and the Possiblity construction, e.g., on pelaste-tta-v-i-ssa [is save-pass-ptc-pl-ine]. The study is based on empirical data of 9000 sentences obtained from i) large collections of transcribed material from Finnish dialects, ii) a corpus of modern Finnish newspaper texts, iii) corpora of Old Finnish texts. Both in colloquial and standard Finnish the reading of the participle is highly dependent of the context and determined by such factors as the overall syntactic environment and other co-occurring elements. One of the main findings here is that the Finnish passive present participle is not modal per se. The contextual modal reading arises whenever the state of affairs is conceptualized from the viewpoint of the implied subject of the participle, and the meaning of possibility or obligation depends mostly on whether the situation is pleasant or undesirable. In sections examining the grammaticalization of the Possibility and Obligation constructions, the perspective is diachronic. Both constructions have derived from copula constructions with the passive present participle as a predicate (adjective or adverb). These sections show how a linguistic change can be investigated on the basis of the patterns of usage in the empirical data. The Possibility construction is currently going through a restructuration to a passive verbal complex. The source of this construction is reflected in its present-day use by the fact that it heavily biased towards a small set of verbs. The Obligation construction has grammaticalized to a construction comparable to a compound tense. Patterns of use of the construction show that grammaticalization originates in specific syntactic constructions with an implication of practical necessity. Furthermore, it is shown that the Obligation construction has grammaticalized in different directions in standard and colloquial Finnish. Differing from the study on most typical phenomena investigated in the literature on grammaticalization of modality, the present study opens new perspectives and methods for discussion on these questions.

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The K-shell diagram (K alpha(1,2) and K beta(1,3)) and hypersatellite (HS) (K-h alpha(1,2)) spectra of Y, Zr, Mo, and Pd have been measured with high energy-resolution using photoexcitation by 90 keV synchrotron radiation. Comparison of the measured and ab initio calculated HS spectra demonstrates the importance of quantum electrodynamical (QED) effects for the HS spectra. Phenomenological fits of the measured spectra by Voigt functions yield accurate values for the shift of the HS from the diagram lines, the splitting of the HS lines, and their intensity ratio. Good agreement with theory was found for all quantities except for the intensity ratio, which is dominated by the intermediacy of the coupling of the angular momenta. The observed deviations imply that our current understanding of the variation of the coupling scheme from LS to jj across the periodic table may require some revision.

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The aim of this masters thesis was to examine subjective wellbeing and personal happiness. Empirical study of happiness is part of broader wellbeing reseach and is based on an idea that the best experts of personal wellbeing are the individuals themselves. In addition to perceptions of personal happiness, the aim was also to acquire knowledge about personal values and components personal happiness is based on. In this study, moving into certain community and the charesteristics of neigbourhood contributing happiness, were defined to represent these values. The object was, through comparative casestudy, to obtain knowledge about subjective wellbeing of the inviduals in two different residental areas inside metropolitan area of Helsinki. In comparative case study the intention usually is that the examined units represent spesific "cases" from something broader and therefore the results can be somehow generalized. Consequently the chosen cases in this study were selected due to their image of "urban village" and thus the juxtapositioning was constructed between secluded post-suburban village and more heterogeneous urban village better attached to excisting urban structure. The researh questins were formed as follows: Are there any differencies between the areas regarding the components personal happines is based on? Are there any differencies between the areas regarding the level of residents subjective wellbeing? Based on the residents assesments, what are the most important charesteristics of neigbourhood contributing personal happiness? The data used in order to gain aswers to these questions was obtained from internet-based survey questionnaire. Based on the data residents of post-suburban village Sundsberg seem to share highly family oriented set of values and actualizing these values is ensured with high income, wealth and secure work situation. Insteadt in Kumpula the components of happiness seem place more towards learning and personal developement, interesting leisure and hobbies and specially having an influence regarding communal decisions. Conserning subjective wellbeing of residents there can be seen some differencies as well. Personal life is experienced a bit more happier in Sundsberg than in Kumpula. People are more satified with their personal health and job satisfaction in Sundsberg and additionally feelings of loneliness, inadequancy and frustration are bit more common in Kumpula. Regarding the charesteristics of neigbourhood contributing happiness data suggests that key charesteristics of area are peacefulness and safely, good location and connections and proximity of parks and recreational areas. These charesteristics were concidered highly significant in both areas but they were experienced to actualize better in Kumpula. In addition to these components the residents in Kumpula were overall more satisfied with various charecteristics contiburing happiness in their residental area. Besides these attributes mentioned above residents in Kumpula emphasize also some "softer" elements connecting into social, functional and communal side of area. From Sundsberg point of view residental area best contributing happiness is child friendly and safe community based on likeminded people who share the same sosioeconomical situation. The results of this study can be linked back into the society and metropolitan area, which they were chosen from as a cases to be studied. The results can thereby be seen as an example of differentation of conditions of personal happiness between certain population segments. It is possible to detect an spatial dimetion to this process as well and thereby the results suggests that regional segmentation affects between high-ranking residental areas as well. Thereby the results of this reseach contributes to the debate on innovative, diverse and dynamic urban area and as well cohesion of metropolitan area and the society in whole.

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Traumatic brain injury (TBI) affects people of all ages and is a cause of long-term disability. In recent years, the epidemiological patterns of TBI have been changing. TBI is a heterogeneous disorder with different forms of presentation and highly individual outcome regarding functioning and health-related quality of life (HRQoL). The meaning of disability differs from person to person based on the individual s personality, value system, past experience, and the purpose he or she sees in life. Understanding of all these viewpoints is needed in comprehensive rehabilitation. This study examines the epidemiology of TBI in Finland as well as functioning and HRQoL after TBI, and compares the subjective and objective assessments of outcome. The frame of reference is the International Classification of Functioning, Disability and Health (ICF). The subjects of Study I represent the population of Finnish TBI patients who experienced their first TBI between 1991 and 2005. The 55 Finnish subjects of Studies II and IV participated in the first wave of the international Quality of life after brain injury (QOLIBRI) validation study. The 795 subjects from six language areas of Study III formed the second wave of the QOLIBRI validation study. The average annual incidence of Finnish hospitalised TBI patients during the years 1991-2005 was 101:100 000 in patients who had TBI as the primary diagnosis and did not have a previous TBI in their medical history. Males (59.2%) were at considerably higher risk of getting a TBI than females. The most common external cause of the injury was falls in all age groups. The number of TBI patients ≥ 70 years of age increased by 59.4% while the number of inhabitants older than 70 years increased by 30.3% in the population of Finland during the same time period. The functioning of a sample of 55 persons with TBI was assessed by extracting information from the patients medical documents using the ICF checklist. The most common problems were found in the ICF components of Body Functions (b) and Activities and Participation (d). HRQoL was assessed with the QOLIBRI which showed the highest level of satisfaction on the Emotions, Physical Problems and Daily Life and Autonomy scales. The highest scores were obtained by the youngest participants and participants living independently without the help of other people, and by people who were working. The relationship between the functional outcome and HRQoL was not straightforward. The procedure of linking the QOLIBRI and the GOSE to the ICF showed that these two outcome measures cover the relevant domains of TBI patients functioning. The QOLIBRI provides the patients subjective view, while the GOSE summarises the objective elements of functioning. Our study indicates that there are certain domains of functioning that are not traditionally sufficiently documented but are important for the HRQoL of persons with TBI. This was the finding especially in the domains of interpersonal relationships, social and leisure activities, self, and the environment. Rehabilitation aims to optimize functioning and to minimize the experience of disability among people with health conditions, and it needs to be based on a comprehensive understanding of human functioning. As an integrative model, the ICF may serve as a frame of reference in achieving such an understanding.

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The removal of noncoding sequences, or introns, from the eukaryotic messenger RNA precursors is catalyzed by a ribonucleoprotein complex known as the spliceosome. In most eukaryotes, two distinct classes of introns exist, each removed by a specific type of spliceosome. The major, U2-type introns account for over 99 % of all introns, and are almost ubiquitous. The minor, U12-type introns are found in most but not all eukaryotes, and reside in conserved locations in a specific set of genes. Due to their slow excision rates, the U12-type introns are expected to be involved in the regulation of the genes containing them by inhibiting the maturation of the messenger RNAs. However, little information is currently available on how the activity of the U12-dependent spliceosome itself is regulated. The levels of many known splicing factors are regulated through unproductive alternative splicing events, which lead to inclusion of premature STOP codons, targeting the transcripts for destruction by the nonsense-mediated decay pathway. These alternative splice sites are typically found in highly conserved sequence elements, which also contain binding sites for factors regulating the activation of the splice sites. Often, the activation is achieved by binding of products of the gene in question, resulting in negative feedback loops. In this study, I show that U11-48K, a protein factor specific to the minor spliceosome, specifically recognizes the U12-type 5' splice site sequence, and is essential for proper function of the minor spliceosome. Furthermore, the expression of U11-48K is regulated through a feedback mechanism, which functions through conserved sequence elements that activate alternative splicing and nonsense-mediated decay. This mechanism is conserved from plants to animals, highlighting both the importance and early origin of this mechanism in regulating splicing factors. I also show that the feedback regulation of U11-48K is counteracted by a component of the major spliceosome, the U1 small nuclear ribonucleoprotein particle, as well as members of the hnRNP F/H protein family. These results thus suggest that the feedback mechanism is finely tuned by multiple factors to achieve precise control of the activity of the U12-dependent spliceosome.