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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
531

Long term effects of MDMA administration in rats during early and late adolescence.

Kolyaduke, Olga January 2011 (has links)
Drug use and abuse for recreational purposes is a common phenomenon, with club drugs such as MDMA (3,4-methylendioxymethamphetamine) being popular for its energetic and euphoric effects – recreating an artificial feeling of “Ecstasy”. Although use of the drug itself has remained relatively constant over the years, the population among which it is popular has been shifting toward younger users, with MDMA use among adolescents becoming more prominent. However research on the effects that MDMA has on the developing adolescent brain has been limited. The current study focuses on the long term effects in rats following chronic MDMA exposure during either early or late adolescence. In adulthood, the rats’ memory, activity and emotional reactivity were assessed through frequency of ambulation, grooming, rearing, defecation, and corner or center occupancy of an open-field, novel object-recognition in the open-field, emergence from a dark chamber into a bright area, and recognition of the changed arm of the Y-maze. The results showed that there were significant long-term effects resulting in increased anxiety for rats treated with MDMA during late adolescence only. This increase of emotional reactivity was indicated through decreased ambulation on the open-field measures, decreased movement between the dark and light chambers, and decreased entries of both arms of the Y-maze. Sex of the animal was also found to differentiate MDMA effects, with females showing a greater increase in anxiety. Measures regarding spatial and working memory were not significant. Overall, the results suggest that animals are more susceptible to long-term effects following MDMA administration in late, but not early adolescence. Furthermore, memory appears to remain unaffected regardless of the age of administration, and only anxiety levels were affected by the drug.
532

The Application of Atheoretical Regression Trees to Problems in Time Series Analysis

Rea, William Stanley January 2008 (has links)
This thesis applies Atheoretical Regression Trees (ART) to the problem of locating changes in mean in a time series where the number and location of those changes are unknown. We undertook an extensive simulation study into ART's performance on a range of time series. We found ART to be a useful addition to currently established structural break methodologies such as the CUSUM and that due to Bai and Perron. ART was found to be useful in the analysis of long time series which are not practical to analyze with the optimal procedure of Bai and Perron. ART was applied to a long standing problem in the analysis of long memory time series. We propose two new methods based on ART for distinguishing between true long memory and spurious long memory due to structural breaks. These methods are fundamentally different from current tests and procedures intended to discriminate between the two sets of competing models. The methods were subjected to a simulation study and shown to be effective in discrimination between simple regime switching models and fractionally integrated processes. We applied the new methods to 16 realized volatility series and concluded they were not fractionally integrated series. All 16 series had mean shifts, some of which could be identified with historical events. We applied the new methods to a range of geophysical time series and concluded they were not fractional Gaussian noises. All of the series examined had mean shifts, some of which could be identified with known climatic changes. We conclude that our new methods are a significant advance in model discrimination in long memory series.
533

Self referencing SPR sensor by simultaneous excitation of long and short range surface plasmon modes

Donipudi, Raghunandan K 01 January 2006 (has links)
A novel surface plasmon resonance sensor is fabricated to evaluate its use in biochemical sensing. The sensor can differentiate between bulk refractive index changes and surface binding reactions of interest. There has been a great interest in developing sensors to differentiate biological or chemical agents from interfering effects, but they still remain in research phase. In this work, a prism coupler is used to simultaneously excite both long and short range surface plasmon modes of the sensor. The differing sensitivities of the long and short range modes allow one to distinguish surface binding reactions of interest from refractive index fluctuations. In this thesis, we have demonstrated the sensors self referencing capability by detecting the formation of an octadecanethiol self assembled monolayer while varying solution refractive index.
534

Les actions françaises depuis 1854 : analyses et découvertes

Le bris, David 01 February 2011 (has links) (PDF)
Le Bris a collecté environ 200 000 données sur les actions françaises entre 1854 et 1988 pour construire un indice de performances.Différents biais qui surestimaient la rentabilité dans les indices français existants sont identifiés. D'autres probables cas à l'étranger sont présentés.Sur le long terme, les actions offrent une meilleure rentabilité que les autres actifs mais sans prime particulière.Par rapport aux actions américaines, les françaises sous-performent y compris durant les périodes de paix.Le marché est très sensible aux changements de gouvernements et surperforme sous ceux de gauche.Une nouvelle méthode de détection des krachs est proposée. Elle identifie des krachs cohérents avec l'histoire.Les entreprises de services dominent la capitalisation boursière de manière quasi-continue depuis 1854.La rationalité des investissements en emprunts russes avant 1914 est démontrée grâce à une optimisation de portefeuille parmi les actifs français (action, obligation, rente) et huit emprunts d'Etats étrangers.Une nouvelle méthode de décomposition du bénéfice de diversification est proposée ; les investisseurs français étaient attirés par la faible corrélation plus que par les rentabilités étrangères supérieures avant 1914.Les actions françaises et américaines présentent une hausse de corrélation sur le long terme probablement suivant l'intégration des économies. Ainsi, l'incitation à diversifier internationalement a baissé.Le risque de marché enregistre une forte hausse durant l'entre-deux-guerres et le niveau pré-1914 n'est jamais retrouvé. Il semble lié à la fin du Gold Standard, à l'inflation et aux déficits publics.Conséquence de la hausse de ce risque commun, la corrélation entre actions françaises augmente, réduisant l'effet de diversification domestique ; a l'opposé un " super effet portefeuille " est identifiée avant 1914.
535

Damn Pinkerton, and all such as he! : Om orientalism i Madame Butterfly

Beverloo, Sebastian January 2014 (has links)
Sebastian Beverloo: "Damn Pinkerton, and all such as he! – Om orientalism i Madame Butterfly." Exa- mensarbete på kandidatnivå i musikvetenskap, Institutionen för musik- och teatervetenskap, Stockholms universitet, ht 2014. Orientalism är teorin att Väst, genom representation i konsten, har förmedlat en ofördelaktig bild av Ori- entens folk, seder och bruk. Begreppet förklarar de estetiska strömningar som följde med den ostindiska handeln och den europeiska kolonialismen. Problemen som teorin om kulturell orientalism sätter fingret på innefattar olika aspekter av representation; hur orientalerna (redan det ett problematiskt begrepp i sig) har gestaltats i konsten. Ett av de centrala problemen är att etnicitet lyfts fram före individualitet: en orien- talisk man är i första hand orientalisk, och bara i andra hand man. Det här arbetet problematiserar repre- sentationen av rollpersonerna i den kvartett av verk, som jag kallar för Madame Geisha-berättelsen (Lotis Madame Chrysanthème (1887), Longs Madame Butterfly (1898), Belascos Madame Butterfly (1900), Puc- cinis Madama Butterfly (1904-7)). Mer specifikt undersöks hur den japanska kvinnan gestaltas genom alla de fyra verken – i synnerhet med hänsyn till relationen mellan japansk kvinnlighet och västerländsk man- lighet. Ett av huvudproblemen är att centralfiguren i berättelsen är en japansk kvinna, trots att ingen av de inblandade författarna var varken japansk eller en kvinna. Verken studeras sida vid sida och jämförs utifrån orientalistiska och genusrelaterade problem. En del av undersökningen ägnas även åt Butterflys påstaådda verkliga ursprung.
536

Agile supply partnerships : the paradox of high-involvement and short-term supply relationships in the Macerata-Fermo footwear district

Cerruti, Corrado 08 1900 (has links)
Despite a general consensus concerning the relevance of supply partnerships to agility, the literature reveals disagreements and contradictions regarding their characteristics and, in particular, their duration. This is, whether partnerships in an agile strategy should be long-term (strategic partnerships) or short-term (agile partnerships). The research joins this debate by investigating the types and characteristics of supply partnerships to achieve agility. The underlying premise of the work is that the type of supply partnership is contingent on the degree of turbulence an agile strategy is designed to face. The research was carried out in the fashion industry, given the relevance of agility in this industry. Specifically, the research focused the supply partnerships developed by the footwear companies in the Macerata-Fermo district, the largest footwear district in Italy. The focus on district companies allow the comparison of several companies sharing a very similar business context, allowing a better control of external variables and increasing the internal validity of the study. The field research consisted of a preliminary survey on agility drivers and agile capabilities in the Macerata-Fermo footwear district, followed by an in-depth investigation on supply partnerships using multiple embedded cases studies. Overall six medium-large footwear companies have been analysed in their supply relationships with respect to five key supply categories. For each supply category, the buyer view of the focal firms has been complemented with a view from the supplier side. In total the fieldwork is built upon 30 interviews with 22 informants from 18 companies for a total of more than 23 hours of interviews. In all cases, except two, the key informant was owner, CEO or general manager of the company, eventually supported by another company manager. In two cases, the interviews data have been strengthened by a longitudinal analysis of purchase orders over eight years. The fieldwork highlights that agility drivers and agile capabilities impact on the footwear companies’ decision of developing agile supply partnerships. Specifically footwear companies that are under the pressure of high-turbulence agility drivers (here represented by a high collection renewal rate) and that have developed strong agile capabilities (here represented by a local supply network and a purchase orders postponement) choose agile supply partnerships with respect to supply categories that are sensitive to the fashion trends and therefore difficult to be sourced in a stable way – season after season – from the same suppliers. The main contribution to theory is related to the characteristics of supply partnerships in an agile strategy and specifically to the apparent paradox of “high-involvement & short- term” relationships (i.e. agile supply partnerships). In spite of the presence of time compression diseconomies in building up partnership and of the loss of relational (non- redeployable) benefits in closing down partnerships, scenarios of high-turbulence can give companies an incentive to look for short-term partnerships. Such finding can support a wider claim that different levels of turbulence call for different agility strategies requiring different capabilities and practices. The main contribution to practice is related to the way agile partnerships are selected, started and ended. Given that many industries are facing an increase in market turbulence, it appears that many companies – even outside the fashion industry – might have to learn how to balance high-involvement supply relationships with respect to a shorter time horizon.
537

Physiological adaptations to taper in competitive distance runners.

Luden, Nicholas D. January 2009 (has links)
Access to abstract permanently restricted to Ball State community only / Access to thesis permanently restricted to Ball State community only / School of Physical Education, Sport, and Exercise Science
538

Historical Trends in Water Quality in the Grand River, Ontario: Reconstruction of Phosphorus Loadings

Shaker, Saliy January 2014 (has links)
Phosphorus, a mineral nutrient, is an essential element in aquatic systems. It is only available for biological activity in the form of orthophosphate and soluble restrictive phosphate. Eutrophication, caused by nutrient enrichment, is a problem in many freshwater systems, which results in increased algal blooms, anoxic conditions, and consequently, biodiversity loss and ecosystem failure. Low dissolved oxygen levels trigger the release of sediment bound phosphorus, which reinforces eutrophication. Nutrients in aquatic systems are provided by point and non-point sources and these sources can be affected by several factors, including population, land-use, and climate change. There are many long-term historical phosphorus studies on rivers, but there are very few that are conducted on the Grand River watershed and none that look at factors that might be driving the phosphorus loadings. The Grand River watershed, located in Ontario, Canada, is a highly agricultural watershed with a growing population of approximately one million. It has experienced eutrophication, which has led to excessive production of cyanobacteria and regions of hypoxia. In this study, historical phosphorus concentration data (Total Phosphorus, Soluble Reactive Phosphorus, and Particulate Phosphorus) in five sites along the Grand River were analyzed temporally and spatially from 1965 to 2010 in the upper, middle, and lower parts of the watershed. The Particulate Phosphorus was calculated by subtracting SRP from TP. Several other data such as climate, land-use, geology, and population were also explored and considered as possible factors that may have influenced the trends over time. TP, SRP, and PP average flow weighted concentrations and fluxes were calculated in 2-6 year intervals. SRP load was higher prior to the early 1970???s, declined in the 1970???s, was more stable in the 1980???s and 1990???s, and increased in the 2000???s. The initial decrease in SRP in the early 1970???s was likely due to the phosphorus ban in detergents in 1973 that was implemented over several years. The constant SRP loadings in the 1980???s and 1990???s, despite population and urban development growth, may have been due to upgrades in waste water treatment plants during that time period. The recent increase in phosphorus in more recent years coincides with a large increase in the number of livestock in the 2000???s and population growth. SRP and PP loads increase from upstream to downstream regions are likely due to nutrient accumulation by the river. The higher loads and concentrations of SRP in the CGR is expected because the region is highly urbanized and contains most of the tile drainage in the watershed.
539

Röster från långtidsarbetslösa: en kvalitativ studie av unga vuxnas upplevelser och hantering kring sin livssituation

Annas, Katja, Håkansson, Per Ranil January 2014 (has links)
Under vårterminen 2014 har vi arbetat kontinuerligt med ämnet långtidsarbetslösa unga vuxna. Detta forskningsområde är en aktuell debatterad fråga i dagens samhälle, och har varit intressant som fenomen att undersöka. Härmed vill vi tacka och rikta vår uppskattning till er som har bistått oss under studiens gång och gjort det möjligt för oss att genomföra samt färdigställa denna kandidatuppsats. Ett stort tack till Arbetsförmedlingen i Trollhättan, som stod för ett varmt mottagande och ett gott samarbete. Vi vill här särskilt rikta ett stort Tack till samtliga intervjudeltagare som så fint ställt upp och berätta om deras personliga erfarenheter gällande långtidsarbetslöshet. Vi anser att utan er hjälp, hade inte denna uppsats blivit av. Sist, men inte minst, ett varmt tack till vår handledare Yngve Mohlin, för hans positiva inställning och inspiration, samt för all konstruktiv kritik och pedagogiskt vägledande under hela processen. Vi har noggrant övervägt för- och nackdelar med att skriva denna studie tillsammans. Det framkom att vi tänker lika varandra, utifrån att båda vill ha en hållbar struktur och en given framförhållning. De olika delarna har gemensamt utarbetats och korrigerats. Studiens intervjuer delades dock upp mellan oss och transkriberades av den motsatta kollegan, för att kunna ta del av informationen i respektive intervjuer. Vi satte upp delmål innehållande slutdatum för att kunna få bra flyt i skriv- och materialinsamlandet. Vår utgångspunkt har varit att vi sätter oss ned och utför samtliga delar tillsammans, då vi har diskuterat och sammanställt materialet till en helhet. Vi känner också att det totala arbetet har varit ömsesidigt och där båda har tagit ansvar för samtliga moment i studien.
540

A study of the time-dependent modulation of galactic cosmic rays in the heliosphere / Dzivhuluwani C. Ndiitwani

Ndiitwani, Dzivhuluwani Christopher January 2005 (has links)
Time-dependent cosmic ray modulation in the heliosphere is studied by using a two-dimensional time dependent modulation model. To compute realistic cosmic ray modulation a compound approach is used, which combines the effect of the global changes in the heliospheric magnetic field magnitude and the current sheet tilt angle to establish realistic time dependent diffusion and drift coefficients. This approach is refined by scaling down drifts additionally (compared to diffusion) towards solar maximum. The amount of drifts needed in the model to realistically compute 2.5 GV proton and electron and 1.2GV electron and helium intensities, as measured by Ulysses from 1990 to 2004, is established. It is shown that the model produces the correct latitudinal gradients evident from the observations during both the Ulysses fast latitude scan periods. Also, much can be learned on the magnitude of perpendicular diffusion in the polar direction, K┴θ, especially for solar minimum conditions and for polarity cycles when particles drift in from the poles. For these periods K┴θ = 0.12K║ in the polar regions (with K║ the parallel diffusion coefficient)and K┴θ /K║ can vary between 0.01 to even 0.04 in the equatorial regions depending on the enhancement factor toward the poles. The model is also applied to compute radial gradients for 2.5 GV cosmic ray electrons and protons in the inner heliosphere. It is shown that, for solar minimum, and in the equatorial regions, the protons (electrons) have a radial gradient of 1.9 %/AU (2.9 %/AU), increasing for both species to a very fluctuating gradient varying between 3 to 4 %/AU at solar maximum. Furthermore, the model also computes realistic electron to proton and electron to helium ratios when compared to Ulysses observations, and charge-sign dependent modulation is predicted up to the next solar minimum expected in 2007. Lastly the model is also applied to model simultaneously galactic cosmic ray modulation at Earth and along the Voyager 1 trajectory, and results are compared with> 70 MeV count rates from Voyager 1 and IMP8. To produce realistic modulation, this model gives the magnitude of perpendicular diffusion in the radial direction as K┴r/K║= 0.035 and that the modulation boundary seemed to be situated between at 120 AU and 140 AU. / Thesis (M.Sc. (Physics))--North-West University, Potchefstroom Campus, 2005.

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