21 resultados para DARK-MATTER HALOES
Resumo:
Pro gradu -tutkielma käsittelee afroamerikkalaisen puhekielen (African American Vernacular English, AAVE) käyttöä kolmen englanninkielisen romaanin dialogissa ja suomen yleispuhekielen käyttöä romaanien käännöksissä. Tutkimus on pääasiassa kvantitatiivinen ja deskriptiivinen. Romaanit ovat Stephen Kingin The Dark Tower II: The Drawing of the Three (1987) (Musta torni 2, Kolme korttia pakasta 2005, suom. Kari Salminen), John Grishamin A Time to Kill (1989) (On aika tappaa 1994, suom. Kimmo Linkama) ja Sapphiren Push (1996) (Precious – harlemilaistytön tarina 2010, suom. Kristiina Drews). Alkukielisten romaanien osalta Grisham ja Sapphire suosivat lauseopillisia kielenpiirteitä, kun taas King on suosinut äänteellisiä. Sen sijaan käännöksissä piirteistä yleisimpiä ovat äänteelliset ja harvinaisimpia lauseopilliset. Vaikka käännöksissä sanastolliset piirteet ovat taajaan esiintyviä, äänteellisiä piirteitä esiintyy niitä enemmän. Poikkeuksena on On aika tappaa, jossa sanastollisia piirteitä esiintyy enemmän kuin äänteellisiä. Tulos eroaa Sampo Nevalaisen vuonna 2003 tekemästä tutkimuksesta, jossa hän sai selville, että käännöksissä käytetyt piirteet olivat enimmäkseen sanastollisia, kun taas alun perin suomeksi kirjoitetussa kaunokirjallisuudessa puhekielisyyden vaikutelma saatiin aikaan pääasiassa äänteellisin keinoin. Mahdollinen selitys tässä tutkimuksessa havaitulle erolle on se, että kahdessa romaanissa esiintyvä leimallinen AAVEn käyttö on saanut kääntäjät käyttämään samanlaisia strategioita kuin suomalaiset kirjailijat murretta kirjoittaessaan.
Resumo:
In this Thesis, we study various aspects of ring dark solitons (RDSs) in quasi-two-dimensional toroidally trapped Bose-Einstein condensates, focussing on atomic realisations thereof. Unlike the well-known planar dark solitons, exact analytic expressions for RDSs are not known. We address this problem by presenting exact localized soliton-like solutions to the radial Gross-Pitaevskii equation. To date, RDSs have not been experimentally observed in cold atomic gases, either. To this end, we propose two protocols for their creation in experiments. It is also currently well known that in dimensions higher than one, (ring) dark solitons are susceptible, in general, to an irreversible decay into vortex-antivortex pairs through the snake instability. We show that the snake instability is caused by an unbalanced quantum pressure across the soliton's notch, linking the instability to the Bogoliubov-de Gennes spectrum. In particular, if the angular symmetry is maintained (or the toroidal trapping is restrictive enough), we show that the RDS is stable (long-lived with a lifetime of order seconds) in two dimensions. Furthermore, when the decay does take place, we show that the snake instability can in fact be reversible, and predict a previously unknown revival phenomenon for the original (many-)RDS system: the soliton structure is recovered and all the point-phase singularities (i.e. vortices) disappear. Eventually, however, the decay leads to an example of quantum turbulence; a quantum example of the laminar-to-turbulent type of transition.
Resumo:
In recent years, there have been studies that show a correlation between the hyperactivity of children and use of artificial food additives, including colorants. This has, in part, led to preference of natural products over products with artificial additives. Consumers have also become more aware of health issues. Natural food colorants have many bioactive functions, mainly vitamin A activity of carotenoids and antioxidativity, and therefore they could be more easily accepted by the consumers. However, natural colorant compounds are usually unstable, which restricts their usage. Microencapsulation could be one way to enhance the stability of natural colorant compounds and thus enable better usage for them as food colorants. Microencapsulation is a term used for processes in which the active material is totally enveloped in a coating or capsule, and thus it is separated and protected from the surrounding environment. In addition to protection by the capsule, microencapsulation can also be used to modify solubility and other properties of the encapsulated material, for example, to incorporate fat-soluble compounds into aqueous matrices. The aim of this thesis work was to study the stability of two natural pigments, lutein (carotenoid) and betanin (betalain), and to determine possible ways to enhance their stability with different microencapsulation techniques. Another aim was the extraction of pigments without the use of organic solvents and the development of previously used extraction methods. Stability of pigments in microencapsulated pigment preparations and model foods containing these were studied by measuring the pigment content after storage in different conditions. Preliminary studies on the bioavailability of microencapsulated pigments and sensory evaluation for consumer acceptance of model foods containing microencapsulated pigments were also carried out. Enzyme-assisted oil extraction was used to extract lutein from marigold (Tagetes erecta) flower without organic solvents, and the yield was comparable to solvent extraction of lutein from the same flowers. The effects of temperature, extraction time, and beet:water ratio on extraction efficiency of betanin from red beet (Beta vulgaris) were studied and the optimal conditions for maximum yield and maximum betanin concentration were determined. In both cases, extraction at 40 °C was better than extraction at 80 °C and the extraction for five minutes was as efficient as 15 or 30 minutes. For maximum betanin yield, the beet:water ratio of 1:2 was better, with possibly repeated extraction, but for maximum betanin concentration, a ratio of 1:1 was better. Lutein was incorporated into oil-in-water (o/w) emulsions with a polar oil fraction from oat (Avena sativa) as an emulsifier and mixtures of guar gum and xanthan gum or locust bean gum and xanthan gum as stabilizers to retard creaming. The stability of lutein in these emulsions was quite good, with 77 to 91 percent of lutein being left after storage in the dark at 20 to 22°C for 10 weeks whereas in spray dried emulsions the retention of lutein was 67 to 75 percent. The retention of lutein in oil was also good at 85 percent. Betanin was incorporated into the inner w1 water phase of a water1-in-oil-inwater2 (w1/o/w2) double emulsion with primary w1/o emulsion droplet size of 0.34 μm and secondary w1/o/w2 emulsion droplet size of 5.5 μm and encapsulation efficiency of betanin of 89 percent. In vitro intestinal lipid digestion was performed on the double emulsion, and during the first two hours, coalescence of the inner water phase droplets was observed, and the sizes of the double emulsion droplets increased quickly because of aggregation. This period also corresponded to gradual release of betanin, with a final release of 35 percent. The double emulsion structure was retained throughout the three-hour experiment. Betanin was also spray dried and incorporated into model juices with different pH and dry matter content. Model juices were stored in the dark at -20, 4, 20–24 or 60 °C (accelerated test) for several months. Betanin degraded quite rapidly in all of the samples and higher temperature and a lower pH accelerated degradation. Stability of betanin was much better in the spray dried powder, with practically no degradation during six months of storage in the dark at 20 to 24 °C and good stability also for six months in the dark at 60 °C with 60 percent retention. Consumer acceptance of model juices colored with spray dried betanin was compared with similar model juices colored with anthocyanins or beet extract. Consumers preferred beet extract and anthocyanin colored model juices over juices colored with spray dried betanin. However, spray dried betanin did not impart any off-odors or off-flavors into the model juices contrary to the beet extract. In conclusion, this thesis describes novel solvent-free extraction and encapsulation processes for lutein and betanin from plant sources. Lutein showed good stability in oil and in o/w emulsions, but slightly inferior in spray dried emulsions. In vitro intestinal lipid digestion showed a good stability of w1/o/w2 double emulsion and quite high retention of betanin during digestion. Consumer acceptance of model juices colored with spray dried betanin was not as good as model juices colored with anthocyanins, but addition of betanin to real berry juice could produce better results with mixture of added betanin and natural berry anthocyanins could produce a more acceptable color. Overall, further studies are needed to obtain natural colorants with good stability for the use in food products.
Resumo:
This thesis in caring science didactics is based on a thinking, where the fundamental basis for the didactic is science-based, i.e. it does not emanate from the nursing profession but brings forward a didactic that grows out of caring science and its core substance and ethos. This view on didactics arises from the caritative theory developed by Eriksson. The overall aim of the study is to clarify the meaning and essence of understanding, as well as to explore and deepen the understanding of student nurses' processes of understanding and becoming with the intention of developing a theory model for caring didactics. The overarching research questions are: What is the essence of understanding (of caring science knowledge)? What are the possibilities and importance of understanding in the appropriation of caring science? What characterizes and impels the process of becoming? The thesis consists of four sub studies and a summary section. The overall methodological approach is hermeneutic involving quantitative as well as qualitative methods. The data for the study has been collected through a longitudinal research project that followed student nurses at three universities during their entire education. The empirical sub studies form the basis for the interpreted knowledge that is formulated in the new understanding. This new understanding have, through additional theory-charging with the theory fragments from Gadamer, generated the heuristic synthesis which is illustrated in the theory model. The findings shows that understanding can be described as something unlimited, as an endless movement, which can be illustrated as a lying eighth, a lemniscate. The lemiscate of understanding is characterized by seeing, knowing and becoming and consists of seven differently named phases; the acquired horizon of understanding, the encounter of horizons, the dialogue of horizons, the fusion of horizons, application, reflection and shaping a new horizon of understanding. Bildung (formation), is the ultimate imprint of the endless spiral movement of understanding. Ethos and arête constitute the hubs around which the lemniscate of understanding circles. These include the spirit and driving force that the student carries within. The caring culture encloses the lemniscate of understanding. The caring culture provides the life space of understanding and the prevailing basic values are evinced in the culture.
Resumo:
Guided by the social-ecological conceptualization of bullying, this thesis examines the implications of classroom and school contexts—that is, students’ shared microsystems—for peer-to-peer bullying and antibullying practices. Included are four original publications, three of which are empirical studies utilizing data from a large Finnish sample of students in the upper grade levels of elementary school. Both self- and peer reports of bullying and victimization are utilized, and the hierarchical nature of the data collected from students nested within school ecologies is accounted for by multilevel modeling techniques. The first objective of the thesis is to simultaneously examine risk factors for victimization at individual, classroom, and school levels (Study I). The second objective is to uncover the individual- and classroom-level working mechanisms of the KiVa antibullying program which has been shown to be effective in reducing bullying problems in Finnish schools (Study II). Thirdly, an overview of the extant literature on classroom- and school-level contributions to bullying and victimization is provided (Study III). Finally, attention is paid to the assessment of victimization and, more specifically, to how the classroom context influences the concordance between self- and peer reports of victimization (Study IV). Findings demonstrate the multiple ways in which contextual factors, and importantly students’ perceptions thereof, contribute to the bullying dynamic and efforts to counteract it. Whereas certain popular beliefs regarding the implications of classroom and school contexts do not receive support, the role of peer contextual factors and the significance of students’ perceptions of teachers’ attitudes toward bullying are highlighted. Directions for future research and school-based antibullying practices are suggested.