22 resultados para stars: kinematics and dynamics


Relevância:

100.00% 100.00%

Publicador:

Resumo:

Climate is warming and it is especially seen in arctic areas, where the warming trend is expected to be greatest. Arctic freshwater ecosystems, which are a very characteristic feature of the arctic landscape, are especially sensitive to climate change. They could be used as early warning systems, but more information about the ecosystem functioning and responses are needed for proper interpretation of the observations. Phytoplankton species and assemblages could be especially suitable for climate-related studies, since they have short generation times and react rapidly to changes in the environment. In addition, phytoplankton provides a good tool for lake classifications, since different species have different requirements and tolerance ranges for various environmental factors. The use of biological indicators is especially useful in arctic areas, were many of the chemical factors commonly fall under the detection limit and therefore do not provide much information about the environment. This work brings new information about species distribution and dynamics of arctic freshwater phytoplankton in relation to environmental factors. The phytoplankton of lakes in Finnish Lapland and other European high-altitude or high-latitude areas were compared. Most lakes were oligotrophic and dominated by flagellated species belonging to chrysophytes, cryptophytes and dinoflagellates. In Finnish Lapland cryptophytes were of less importance, whereas desmids had high species richness in many of the lakes. In Pan-European scale, geographical and catchment-related factors were explaining most of the differences in species distributions between different districts, whereas lake water chemistry (especially conductivity, SiO2 and pH) was most important regionally. Seasonal and interannual variation of phytoplankton was studied in subarctic Lake Saanajärvi. Characteristic phytoplankton species in this oligotrophic, dimictic lake belonged mainly to chrysophytes and diatoms. The maximum phytoplankton biomass in Lake Saanajärvi occurs during autumn, while spring biomass is very low. During years with heavy snow cover the lake suffers from pH drop caused by melt waters, but the effects of this acid pulse are restricted to surface layers and last for a relatively short period. In addition to some chemical parameters (mainly Ca and nutrients), length of the mixing cycle and physical factors such as lake water temperature and thermal stability of water column had major impact on phytoplankton dynamics. During a year with long and strong thermal stability, the phytoplankton community developed towards an equilibrium state, with heavy dominance of only a few taxa for a longer period of time. During a year with higher windiness and less thermal stability, the species composition was more diverse and species with different functional strategies were able to occur simultaneously. The results of this work indicate that although arctic lakes in general share many common features concerning their catchment and water chemistry, large differences in biological features can be found even in a relatively small area. Most likely the lakes with very different algal flora do not respond in a similar way to differences in the environmental factors, and more information about specific arctic lake types is needed. The results also show considerable year to year differences in phytoplankton species distribution and dynamics, and these changes are most likely linked to climatic factors.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Protein conformations and dynamics can be studied by nuclear magnetic resonance spectroscopy using dilute liquid crystalline samples. This work clarifies the interpretation of residual dipolar coupling data yielded by the experiments. It was discovered that unfolded proteins without any additional structure beyond that of a mere polypeptide chain exhibit residual dipolar couplings. Also, it was found that molecular dynamics induce fluctuations in the molecular alignment and doing so affect residual dipolar couplings. The finding clarified the origins of low order parameter values observed earlier. The work required the development of new analytical and computational methods for the prediction of intrinsic residual dipolar coupling profiles for unfolded proteins. The presented characteristic chain model is able to reproduce the general trend of experimental residual dipolar couplings for denatured proteins. The details of experimental residual dipolar coupling profiles are beyond the analytical model, but improvements are proposed to achieve greater accuracy. A computational method for rapid prediction of unfolded protein residual dipolar couplings was also developed. Protein dynamics were shown to modulate the effective molecular alignment in a dilute liquid crystalline medium. The effects were investigated from experimental and molecular dynamics generated conformational ensembles of folded proteins. It was noted that dynamics induced alignment is significant especially for the interpretation of molecular dynamics in small, globular proteins. A method of correction was presented. Residual dipolar couplings offer an attractive possibility for the direct observation of protein conformational preferences and dynamics. The presented models and methods of analysis provide significant advances in the interpretation of residual dipolar coupling data from proteins.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Tutkimuksen keskeinen tehtävä on selvittää, mikä on dokumentoinnin merkitys lastensuojelun sosiaalityön tiedonmuodostuksessa ja ammattikäytännöissä. Asiakirjateksteistä koostuvaa tutkimusaineistoa tarkastellaan kolmesta eri suunnasta kysymällä: 1)Miten asiakirjoja kirjoitetaan? 2) Mitä asiakirjoihin kirjoitetaan? 3) Miksi asiakirjoja kirjoitetaan niin kuin kirjoitetaan? Tutkimusaineisto muodostuu lastensuojelun sosiaalityöntekijöiden laatimista asiakastietojärjestelmään tallennetuista muistiinpanoista ja huostaanottopäätöksistä. Tutkimukseen on valittu 20 huostaanotetun eri-ikäisen lapsen ja heidän perheensä asiakirjat yhteensä 1613 asiakirjatulostussivua. Tekstit ajoittuvat vuodesta 1989 vuoteen 2000. Tutkimusmenetelmä on diskurssianalyyttinen ja tukeutuu Fairclough`n (1997)esittämään kolmiulotteiseen malliin, jossa diskurssi määritellään tekstin, käytäntöjen ja sosiokulttuurisen ympäristön suhteeksi. Diskurssianalyysi on näiden rakenteiden ja niiden välisten suhteiden kuvaamista, tulkintaa ja selittämistä. Fairclough’n mallia mukaillen tutkimuksen analyysi koostuu retoriikan ja tematiikan analyyseistä sekä pragmatiikan näkökulman sisältävästä tarkastelusta. Asiakirjatekstien pilkkominen puhujakategorioihin osoitti tekstien olevan moniäänisiä, useiden henkilöiden näkemyksiä ja mielipiteitä sisältäviä tekstipintoja. Retoriikan analyysi näytti, että lastensuojelun sosiaalityön asiakirjat sisältävät paljon dynaamisia kuvauksia työstä. Asiakirjojen kirjoittaminen moniäänisiksi tuo tekstiin uskottavuutta, ja se on myös yksi retorinen vaikuttamiskeino. Tematiikan tarkastelu osoitti,että asiakirjojen sisällölliset teemat (lapsen hoiva, arjen hallinta, yhteistyö ja päihteiden käyttö) ja kokemukselliset teemat (huoli, vastuu, yhteys ja moraali) toistuvat sisäkkäisinä ja päällekkäisinä säikeinä dynaamisesti vaihdellen. Sosiaalityöntekijät kirjaavat teksteihin monia yhtäaikaisia teemoja, joiden avulla rakentavat ammatillista ymmärrystä kyseessä olevasta tilanteesta. Asiakirjojen tutkiminen pragmatiikan suunnasta toi esiin, kirjoittamisen ja lukemisen kontekstiulottuvuudet sekä tiedonmuodostusprosessin. Asiakirjojen laatiminen on osa sosiaalityön käytäntöjä. Se on myös keskeinen alue ammattikunnan yhteisen ammatillisen ymmärryksen luomisessa ja ylläpitämisessä. Muistiinpanot, huostaanottopäätökset ja lakitekstit ovat intertekstuaalisia. Lastensuojelun sosiaalityön asiakirjojen tutkiminen on avannut uusia mahdollisuuksia ymmärtää sosiaalityön dokumentointiprosessia, merkitystä ja roolia sekä tiedonmuodostuksen dynamiikkaa. Tekstien kirjoittaminen, niiden lukeminen, tietojen siirtäminen ja asiakkaan kuuleminen samoin kuin kuulemisen kirjaaminen ovat sosiaalityön dokumentoinnin keskeisiä haasteita. Tutkimus pyrkii avaamaan ymmärrystä asiakirjatekstien monivivahteiseen ja dynaamiseen maailmaan ja siten myös sosiaalityön dokumentoinnin arkeen. Tarkastelut mahdollistavat työn kehittämisen erityisesti sosiaalityön asiakasvaikuttavuuden mittaamisen ja parantamisen suuntaan. Asiakirjoissa ilmenevä tiedonmuodostuksen dynamiikka syntyy kirjoittamiskäytäntöjen, kirjoittamisen ja lukemisen sekä toimintakäytäntöjen yhteisessä alueessa. Avainsanat: sosiaalityö, lastensuojelu, dokumentointi, asiakirja, diskurssianalyysi, tiedonmuodostus.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In today’s business one can say that competition does not take place inside the network, but between networks. Change and dynamics are central issues in network studies, and a company, due its changing environment, can identify opportunities and threats and respond to them accordingly. These opportunities are vital, but also complex and demanding for the management. Earlier research has identified a shortcoming in explanations of how the micro-level interactions to macro-level patterns are connected. The IMP-group has been trying to fill this research gap with research on interactions within business networks. In this area of research lies the focus of research on relationships between organizations. Adaptation in cooperation is a central concept within business network research. Adaptation has been dealt with in previous literature, but the focus of the studies has mainly been outside this phenomenon, and it has mostly had a supporting role. Most literature has also described the buyers' point of view in studied supply networks, whereas much less attention has been paid to the suppliers' view on them. This study focuses on this research gap. The results of the study stress that adaptation should be included to a greater extent in the strategy work of companies. The adaptations should be carefully planned and, as far as possible, made consciously. Conscious, well-planned adaptations can be seen as investments into present and future relationships, and resources should be invested into something that does not increase the company’s dependence, but divides the power in the relationship between the companies. Adaptations should be planned so that they result in a more offensive way of responding to the demands that are placed upon the companies. In this way, the actions can be viewed and analyzed in accordance with whether the actions make the company weaker or stronger.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In the markets-as-networks approach business networks are conceived as dynamic actor structures, giving focus to exchange relationships and actors’ capabilities to control and co-ordinate activities and resources. Researchers have shared an understanding that actors’ actions are crucial for the development of business networks and for network dynamics. However, researchers have mainly studied firms as business actors and excluded individuals, although both firms and individuals can be seen as business actors. This focus on firms as business actors has resulted in a paucity of research on human action and the exchange of intangible resources in business networks, e.g. social exchange between individuals in social networks. Consequently, the current conception of business networks fails to appreciate the richness of business actors, the human character of business action and the import of social action in business networks. The central assumption in this study is that business actors are multidimensional and that their specific constitution in any given situation is determined by human interaction in social networks. Multidimensionality is presented as a concept for exploring how business actors act in different situations and how actors simultaneously manage multiple identities: individual, organisational, professional, business and network identities. The study presents a model that describes the multidimensionality of actors in business networks and conceptualises the connection between social exchange and human action in business networks. Empirically the study explores the change that has taken place in pharmaceutical retailing in Finland during recent years. The phenomenon of emerging pharmacy networks is highly contemporary in the Nordic countries, where the traditional license-based pharmacy business is changing. The study analyses the development of two Finnish pharmacy chains, one integrated and one voluntary chain, and the network structures and dynamics in them. Social Network Analysis is applied to explore the social structures within the pharmacy networks. The study shows that emerging pharmacy networks are multifaceted phenomena where political, economic, social, cultural, and historical elements together contribute to the observed changes. Individuals have always been strongly present in the pharmacy business and the development of pharmacy networks provides an interesting example of human actors’ influence in the development of business networks. The dynamics or forces driving the network development can be linked to actors’ own economic and social motives for developing the business. The study highlights the central role of individuals and social networks in the development of the two studied pharmacy networks. The relation between individuals and social networks is reciprocal. The social context of every individual enables multidimensional business actors. The mix of various identities, both individual and collective identities, is an important part of network dynamics. Social networks in pharmacy networks create a platform for exchange and social action, and social networks enable and support business network development.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Purpose This paper takes a customer view on corporate image and value, and discusses the value of image in service. We propose a model depicting how the customer’s corporate brand image affects the customer’s value-in-use. Methodology/approach The paper represents conceptual development on customers’ value and image construction processes. By integrating ideas and elements from the current service and branding literature a model is proposed that extends current views on how value-in-use emerges. Findings From a current service perspective it is the customer who makes value assessments when experiencing service. Similarly, if branding is a concept used to denote the service provider’s intentions and attempts to create a corporate brand, image construction is the corresponding process where the customer constructs the corporate image. This image construction process is always present both in service interactions and in communication and has an effect on the customer’s value-in-use. We argue that two interrelated concepts are needed to capture corporate image construction and dynamics and value-in-use – the image-in-use and image heritage. Research implications The model integrates two different streams of research pointing to the need to consider traditional marketing communication and service interactions as inherently related to each other from the customer’s point of view. Additionally the model gives a platform for understanding how value-in-use emerges over time. New methodological approaches and techniques to capture image-in-use and image heritage and their interplay with value-in-use are needed. Practical implications The company may not be able to control the emergence of value-in-use but may influence it, not only in interactions with the customer but also with pure communication. Branding activities should therefore be considered related to service operations and service development. Additionally, practitioners would need to apply qualitative methods to understand the customer’s view on image and value-in-use. Originality/value The paper presents a novel approach for understanding and studying that the customer’s image of a company influences emergence of value-in-use. The model implies that the customer’s corporate image has a crucial role for experienced value-in-use.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Microcatchment water harvesting (MCWH) improved the survival and growth of planted trees on heavy soils in eastern Kenya five to six years after planting. In the best method, the cross-tied furrow microcatchments, the mean annual increments (MAI; based on the average biomass of living trees multiplied by tree density and survival) of the total and usable biomass in Prosopis juliflora were 2787 and 1610 kg ha-1 a-1 respectively, when the initial tree density was 500 to 1667 trees per hectare. Based on survival, the indigenous Acacia horrida, A. mellifera and A. zanzibarica were the most suitable species for planting using MCWH. When both survival and yield were considered, a local seed source of the introduced P. juliflora was superior to all other species. The MAI in MCWH was at best distinctly higher than that in the natural vegetation (163­307 and 66­111 kg ha-1 a-1 for total and usable biomass respectively); this cannot satisfy the fuelwood demand of concentrated populations, such as towns or irrigation schemes. The density of seeds of woody species in the topsoil was 40.1 seeds m-2 in the Acacia-Commiphora bushland and 12.6 seeds m-2 in the zone between the bushland and the Tana riverine forest. Rehabilitation of woody vegetation using the soil seed bank alone proved difficult due to the lack of seeds of desirable species. The regeneration and dynamics of woody vegetation were also studied both in cleared and undisturbed bushland. A sub-type of Acacia-Commiphora bushland was identified as Acacia reficiens bushland, in which the dominant Commiphora species is C. campestris. Most of the woody species did not have even-aged populations but cohort structures that were skewed towards young individuals. The woody vegetation and the status of soil nutrients were estimated to recover in 15­20 years on Vertic Natrargid soils after total removal of above-ground vegetation.