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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.
41

Health promoting palliative care through higher education reform : development and evaluation of a new humanities course in thanatology

Ho, Andy Hau Yan January 2016 (has links)
Under a socio-cultural backdrop where death and loss is heavily stigmatized and community resources for the dying and the bereaved are lacking, Hong Kong requires a public health approach for empowering its people to become active participants in the governance of mortality. “Health-promoting palliative care” (HPPC) translates the hospice ideals of total person care into much broader public health languages and practices, focusing not only on palliation but also prevention, harm reduction, community action, policy advocacy, and most importantly, education and research. Despite their significance, life and death education and Thanatology research has received little attention in Hong Kong. The recent General Education (GE) reform for tertiary institutions, which aims to nurture students’ creativity and civility through the liberal arts, provides a timely opportunity to actualize HPPC. The current study provides a formative account of the development and implementation of a new thanatology course, “The Last Dance: Understanding Death and Dying” offered by the University of Hong Kong, and critically examines its efficacy for reducing negative death perceptions and enhancing positive life attitudes among a group of undergraduate students. Adopting a mixed methods research design and a holistic approach to education evaluation, it utilizes: 1) a quantitative pretest-posttest survey to assess course effectiveness with the standardized tools of Death Attitude Profile-Revised, Meaning-in-Life Scale and Spirituality Scale, as well as a series of ad hoc items on traditional death taboos and death preparedness behaviors; and 2) a qualitative analysis of 100 randomly selected students’ reflective writings for identifying factors that facilitate effective learning. Results from paired-sample t-test with 85 students who have successfully completed the pretest-posttest survey provide robust evidence that The Last Dance was effective in significantly reducing students’ fear of death, death avoidance tendency, and taboo beliefs that oppress death, while promoting active participation in the governance of mortality through increased death preparedness behaviors. Moreover, The Last Dance was found to be effective in enhancing students’ sense of meaning in life, spirituality and interconnectedness. Framework analysis of Students’ reflective writing revealed 12 themes that illuminate the specific learning contents, pedagogy activities, key attitudinal and behavioral changes, as well as significant learning outcomes which supported the quantitative results. These 12 themes were organized into four categories: 1) “Mortality Matters”, which includes Consideration of Palliative Care and Euthanasia, Expression of Death via Arts and Media, and Exploration of Death Rituals and Spirituality; 2) “Teachable Moments” which includes Multi-Media Lectures, Funeral Home Visitation, and Examination of life; 3) “Shifting Perspectives”, which encompasses Cultivating Insights, Renewing Meaning, and Applying Knowledge; and 4) “Ego Awakening” which encompasses Normalization of death, Appreciation of Life, and Recognition of Common Humanity. These 4 categories and their respective 12 themes together form a “Thanatology Pathway to Transformative Growth”, highlighting the vital significance of carefully integrating stimulating learning contents with engaging pedagogical activities for developing an effective and holistic thanatology curriculum; one that focuses not only on skills and knowledge transfer, but also on cultivating life appreciation and compassionate living through an enhanced understanding of death, dying and bereavement.
42

Investigating the Puzzling Synchrotron Behaviour of Mrk 421

Carnerero, Maria, Raiteri, Claudia, Villata, Massimo, Acosta Pulido, Jose, Smith, Paul, Larionov, Valeri 04 November 2016 (has links)
We investigate the multiwavelength behaviour of the high-energy peaked BL Lac object (HBL) Mrk 421 at redshift z = 0.031 in the period 2007-2015. We use optical photometric, spectroscopic, and polarimetric data and near-infrared data obtained by 35 observatories participating in the GLAST-AGILE Support Program (GASP) of the Whole Earth Blazar Telescope (WEBT), as well as by the Steward Observatory Support of the Fermi Mission. We also employ high-energy data from the Swift (UV and X-rays) satellite to study correlations among emission in different bands.
43

A SEARCH FOR SPECTRAL HYSTERESIS AND ENERGY-DEPENDENT TIME LAGS FROM X-RAY AND TeV GAMMA-RAY OBSERVATIONS OF Mrk 421

Abeysekara, A. U., Archambault, S., Archer, A., Benbow, W., Bird, R., Buchovecky, M., Buckley, J. H., Bugaev, V., Cardenzana, J. V, Cerruti, M., Chen, X., Ciupik, L., Connolly, M. P., Cui, W., Eisch, J. D., Falcone, A., Feng, Q., Finley, J. P., Fleischhack, H., Flinders, A., Fortson, L., Furniss, A., Griffin, S., Håkansson, M. HN., Hanna, D., Hervet, O., Holder, J., Humensky, T. B., Kaaret, P., Kar, P., Kertzman, M., Kieda, D., Krause, M., Kumar, S., Lang, M. J., Maier, G., McArthur, S., McCann, A., Meagher, K., Moriarty, P., Mukherjee, R., Nieto, D., Ong, S. OR. A., Otte, A. N., Park, N., Pelassa, V., Pohl, M., Popkow, A., Pueschel, E., Ragan, K., Reynolds, P. T., Richards, G. T., Roache, E., Sadeh, I., Santander, M., Sembroski, G. H., Shahinyan, K., Staszak, D., Telezhinsky, I., Tucci, J. V., Tyler, J., Wakely, S. P., Weinstein, A., Wilhelm, A., Williams, D. A., Ahnen, M. L., Ansoldi, S., Antonelli, L. A., Antoranz, P., Arcaro, C., Babic, A., Banerjee, B., Bangale, P., Almeida, U. Barres de, Barrio, J. A., González, J. Becerra, Bednarek, W., Bernardini, E., Berti, A., Biasuzzi, B., Biland, A., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Carosi, R., Carosi, A., Chatterjee, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Cumani, P., Da Vela, P., Dazzi, F., De Angelis, A., De Lotto, B., de Oña Wilhelmi, E., Di Pierro, F., Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Einecke, S., Glawion, D. Eisenacher, Elsaesser, D., Engelkemeier, M., Ramazani, V. Fallah, Fernández-Barral, A., Fidalgo, D., Fonseca, M. V., Font, L., Fruck, C., Galindo, D., López, R. J. García, Garczarczyk, M., Gaug, M., Giammaria, P., Godinović, N., Gora, D., Guberman, D., Hadasch, D., Hahn, A., Hassan, T., Hayashida, M., Herrera, J., Hose, J., Hrupec, D., Hughes, G., Idec, W., Kodani, K., Konno, Y., Kubo, H., Kushida, J., Lelas, D., Lindfors, E., Lombardi, S., Longo, F., López, M., López-Coto, R., Majumdar, P., Makariev, M., Mallot, K., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martínez, M., Mazin, D., Menzel, U., Mirzoyan, R., Moralejo, A., Moretti, E., Nakajima, D., Neustroev, V., Niedzwiecki, A., Rosillo, M. Nievas, Nilsson, K., Nishijima, K., Noda, K., Nogués, L., Nöthe, M., Paiano, S., Palacio, J., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Paredes-Fortuny, X., Pedaletti, G., Peresano, M., Perri, L., Persic, M., Poutanen, J., Moroni, P. G. Prada, Prandini, E., Puljak, I., Garcia, J. R., Reichardt, I., Rhode, W., Ribó, M., Rico, J., Saito, T., Satalecka, K., Schroeder, S., Schweizer, T., Shore, S. N., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Stamerra, A., Strzys, M., Surić, T., Takalo, L., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Torres, D. F., Torres-Albà, N., Toyama, T., Treves, A., Vanzo, G., Acosta, M. Vazquez, Vovk, I., Ward, J. E., Will, M., Wu, M. H., Zanin, R., Hovatta, T., de la Calle Perez, I., Smith, P. S., Racero, E., Baloković, M. 22 December 2016 (has links)
Blazars are variable emitters across all wavelengths over a wide range of timescales, from months down to minutes. It is therefore essential to observe blazars simultaneously at different wavelengths, especially in the X-ray and gamma-ray bands, where the broadband spectral energy distributions usually peak. In this work, we report on three " target-of-opportunity" observations of Mrk 421, one of the brightest TeV blazars, triggered by a strong flaring event at TeV energies in 2014. These observations feature long, continuous, and simultaneous exposures with XMM-Newton (covering the X-ray and optical/ultraviolet bands) and VERITAS (covering the TeV gamma-ray band), along with contemporaneous observations from other gamma-ray facilities (MAGIC and Fermi-Large Area Telescope) and a number of radio and optical facilities. Although neither rapid flares nor significant X-ray/TeV correlation are detected, these observations reveal subtle changes in the X-ray spectrum of the source over the course of a few days. We search the simultaneous X-ray and TeV data for spectral hysteresis patterns and time delays, which could provide insight into the emission mechanisms and the source properties (e. g., the radius of the emitting region, the strength of the magnetic field, and related timescales). The observed broadband spectra are consistent with a one-zone synchrotron self-Compton model. We find that the power spectral density distribution at greater than or similar to 4 x 10(-4) Hz from the X-ray data can be described by a power-law model with an index value between 1.2 and 1.8, and do not find evidence for a steepening of the power spectral index (often associated with a characteristic length scale) compared to the previously reported values at lower frequencies.
44

Electromagnetic induction on an expanding conducting sphere.

January 1964 (has links)
References: p.71. / Contract DA36-039-AMC-03200(E). Grant DA-SIG-36-039-61-G14.
45

Συμπεριφορική χρηματοοικονομική : τα φαινόμενα του συντηρητισμού και της αντιπροσώπευσης στο London Stock Exchange

Καριοφύλλας, Σπυρίδων 12 March 2015 (has links)
Σκοπός της παρούσας Διδακτορικής Διατριβής (ΔΔ), είναι να ελέγξουμε το εύρος των επιδράσεων δύο ευρέως διαδεδομένων ψυχολογικών φαινομένων (γνωστικά σφάλματα), του συντηρητισμού και της αντιπροσώπευσης, στο Χρηματιστήριο του Λονδίνου για την περίοδο από το 1980 έως το 2012. Για να ικανοποιήσουμε τον παραπάνω σκοπό, χρησιμοποιήσαμε τις προσέγγιση των τάσεων και της σταθερότητας στις χρηματοοικονομικές επιδόσεις . Αναλύσαμε αν η σταθερότητα των παρελθουσών επιδόσεων σε συγκεκριμένους χρηματοοικονομικούς δείκτες, έχει προβλεπτική ικανότητα για τις μελλοντικές τιμές των μετοχών, ελέγχοντας τρεις διατυπωμένες υποθέσεις (Hypothesis Tests). Προκειμένου να απαντήσουμε θέματα ευρωστίας και αξιοπιστίας, υπολογίσαμε και συγκρίναμε τις υπερβάλλουσες αποδόσεις (abnormal returns) με διάφορες μεθόδους (single, three and four factors). Επίσης για αξιοποίηση των πολυπαραγοντικών μοντέλων, χρησιμοποιήσαμε μια εναλλακτική μέθοδο υπολογισμού των three and four factor models, που παρουσιάστηκε από τους Gregory et al. (2013) και ελέγχθηκε αποκλειστικά για την αγορά του Λονδίνου. Τα αποτελέσματα είναι μικτά, και υποστηρίζουν το βαθμό επίδρασης των δύο φαινομένων στις αποδόσεις, ανάλογα με την περίοδο εξέτασης και τις μεθόδους υπολογισμού των αποδόσεων. Ειδικότερα, οι υπερβάλλουσες αποδόσεις που παρατηρήθηκαν με τα πολυπαραγοντικά μοντέλα, επιβεβαιώνουν ευρέως την ύπαρξη των υπό εξέταση γνωστικών σφαλμάτων, σε αντίθεση με τα αποτελέσματα που προκύπτουν από το μονοπαραγοντικό μοντέλο. / The aim of this academic research is to examine the potential magnitude of the impact of two well known psychological phenomena, such as representativeness and conservatism, in the London Stock Exchange (LSE) for the period of 1980 to 2012. To fulfil this purpose, the approaches of trend and consistency in the accounting performance are followed. We analyzed whether the stability of past performance in specific financial ratios, has predictive power for future stock prices, by testing three formulated hypotheses (Hypothesis Tests). In order to address questions about robustness and reliability, we calculated and compared the excess returns (abnormal returns) with various methods (single, three and four factors). Also in order to take advantage of the multifactor models, we used an alternative method of calculation for three and four factor models, presented by Gregory et al. (2013) and tested exclusively for the London market. The results are analysed thoroughly and compared in sub periods, namely, before and after the recent financial crisis. The conclusions are mixed, and the findings support the dependence of the two cognitive biases upon the examined period and the abnormal returns calculation method. Specifically, the results of abnormal returns obtained by the multifactor models largely confirm the existence of the psychological phenomena examined, which is in contrast to those of the single factor model, which derives variations depending on the examined biases.
46

The effects of cafeteria diet feeding on maternal adaptation to pregnancy, growth and development of fetus and glucose homeostasis later in life

Akyol, Asli January 2011 (has links)
Both epidemiological and experimental studies have demonstrated adverse effects of maternal obesity upon both maternal and fetal health. It has been shown that feeding a cafeteria diet in rat pregnancy can induce altered food preferences and greater weight gain in the resulting offspring. This study firstly aimed to examine the effect of diet-induced obesity, or high fat feeding on maternal adaptation to pregnancy and fetal growth. Forty-eight 3-weekold virgin female Wistar rats were randomly divided into two groups fed control (n=24) and cafeteria diet (n=23). 8 weeks later, all rats were mated and after confirming pregnancy half of the rats fed cafeteria diet switched to control, and half of the control rats switched to the cafeteria diet. Maternal cafeteria diet feeding prior to pregnancy resulted in profound adiposity, but did not compromise physiological adaptation to pregnancy or impact upon reproductive success. Maternal cafeteria diet feeding during pregnancy only or maternal obesity induced distinct effects on fetal growth, with pregestational obesity resulting in reduced fetal weight at 20 days gestation. In contrast, cafeteria diet feeding during pregnancy only resulted in increased fetal weight. The main focus of the study was the development of the fetus, and consideration of whether maternal obesity, or cafeteria diet feeding during pregnancy determined body weight, body composition, metabolic biomarkers and glucose homeostasis throughout life. With respect to this point, the same study design was used with additional nutritional challenges during lactation and post-weaning. In contrast to the literature, offspring exposed to cafeteria diet at any stage pre-weaning, showed no evidence of hyperphagia or increased adiposity. Adult offspring exposed to cafeteria diet in early life and weaned onto chow diet, had low fasting glucose and insulin concentrations and were more sensitive to insulin during an i.p. glucose tolerance test. When weaned onto cafeteria diet, offspring exhibited glucose intolerance. There was evidence that rats arrived at a glucose intolerant state via different mechanistic routes which were dependent on the feeding regime during lactation. The data suggested that components of the insulin signalling pathway may be targets for programming by maternal obesity, but that IRS2 and Akt2 do not play major roles. There was also evidence of pancreatic insufficiency in some groups of animals that were fed cafeteria diet during lactation. The observations in this study confirm that maternal over-nutrition and obesity during pregnancy are risk factors for metabolic disturbance in the resulting offspring. The effects on glucose homeostasis were independent of offspring adiposity. However the programming of a glucose intolerant phenotype was dependent upon consumption of cafeteria diet during the post-weaning period.
47

Dissecting the long-term emission behaviour of the BL Lac object Mrk 421

Carnerero, M. I., Raiteri, C. M., Villata, M., Acosta-Pulido, J. A., Larionov, V. M., Smith, P. S., D'Ammando, F., Agudo, I., Arévalo, M. J., Bachev, R., Barnes, J., Boeva, S., Bozhilov, V., Carosati, D., Casadio, C., Chen, W. P., Damljanovic, G., Eswaraiah, E., Forné, E., Gantchev, G., Gómez, J. L., González-Morales, P. A., Griñón-Marín, A. B., Grishina, T. S., Holden, M., Ibryamov, S., Joner, M. D., Jordan, B., Jorstad, S. G., Joshi, M., Kopatskaya, E. N., Koptelova, E., Kurtanidze, O. M., Kurtanidze, S. O., Larionova, E. G., Larionova, L. V., Latev, G., Lázaro, C., Ligustri, R., Lin, H. C., Marscher, A. P., Martínez-Lombilla, C., McBreen, B., Mihov, B., Molina, S. N., Moody, J. W., Morozova, D. A., Nikolashvili, M. G., Nilsson, K., Ovcharov, E., Pace, C., Panwar, N., Pastor Yabar, A., Pearson, R. L., Pinna, F., Protasio, C., Rizzi, N., Redondo-Lorenzo, F. J., Rodríguez-Coira, G., Ros, J. A., Sadun, A. C., Savchenko, S. S., Semkov, E., Slavcheva-Mihova, L., Smith, N., Strigachev, A., Troitskaya, Yu. V., Troitsky, I. S., Vasilyev, A. A., Vince, O. 12 1900 (has links)
We report on long-term multiwavelength monitoring of blazar Mrk 421 by the GLAST-AGILE Support Program of the Whole Earth Blazar Telescope (GASP-WEBT) collaboration and Steward Observatory, and by the Swift and Fermi satellites. We study the source behaviour in the period 2007-2015, characterized by several extreme flares. The ratio between the optical, X-ray and gamma-ray fluxes is very variable. The gamma-ray flux variations show a fair correlation with the optical ones starting from 2012. We analyse spectropolarimetric data and find wavelength-dependence of the polarization degree (P), which is compatible with the presence of the host galaxy, and no wavelength dependence of the electric vector polarization angle (EVPA). Optical polarimetry shows a lack of simple correlation between P and flux and wide rotations of the EVPA. We build broad-band spectral energy distributions with simultaneous near-infrared and optical data from the GASP-WEBT and ultraviolet and X-ray data from the Swift satellite. They show strong variability in both flux and X-ray spectral shape and suggest a shift of the synchrotron peak up to a factor of similar to 50 in frequency. The interpretation of the flux and spectral variability is compatible with jet models including at least two emitting regions that can change their orientation with respect to the line of sight.
48

Propuesta de mejora del proceso productivo de muebles de melamina en la empresa Fabricaciones Metálicas Fametal S.A.C. para aumentar la rentabilidad

Morocho Incio, Luis Alonso January 2019 (has links)
La presente investigación se realizó en las instalaciones de la empresa Fabricaciones Metálicas FAMETAL S.A.C., una empresa peruana del sector manufacturero dedicada a la producción de estructuras metálicas y mobiliario de melamina. Esta empresa presentaba métodos de trabajos no estandarizados que duraban 590,41 minutos por unidad y tiempos no productivos de 25,74 minutos por unidad que limitaban la producción a 1790 unidades por año, asimismo un balance de línea empírico con el que trabajaban presentaba una eficiencia del 74%, la ganancia por la venta de cada producto era de 34 céntimos de sol por cada sol invertido. Ante esta problemática se determinó estandarizar el método de producción a través de la asignación de procedimientos a los operarios y el uso de tiempos estándar, lo cual redujo el tiempo de proceso en 55,64%; se realizó una nueva distribución de planta mediante los métodos SLP y de Güerchet, que redujo los tiempos de transportes en 49,31%, y se balanceó la línea de producción de muebles de melamina logrando reducir el tiempo de ciclo en 55,25%, se aumentó la producción en 123,46% y elevando la eficiencia de línea a 89,74%. Finalmente se analizó la rentabilidad de la propuesta de mejora, la cual presenta una relación beneficio/costo de 1,21, y se aumentó la eficiencia económica de la producción de muebles de melamina de 1,34 a 1,54.
49

Phonetic and phonological variability in the L1 and L2 of late bilinguals: The case of /r/ and /l/ / Phonetische und phonologische Variabilität in der L1 und L2 von späten Bilingualen: Der Fall von /r/ und /l/

Himmel, Marie-Christin January 2021 (has links) (PDF)
A large body of research has shown that a late bilingual’s L1 and L2 phonetic categories influence each other, yielding deviations from monolingual norms in the phonetics of both languages. Existing models of L2 sound acquisition (e.g., the Speech Learning Model; Flege, 1995, 2007) predict unified phonetic spaces which accommodate both L1 and L2 sound categories. Such connections between an L1 and an L2 are believed to lead to persistent non-nativelikeness in the L2, but also to divergence from the monolingual norm in the L1, as shown in numerous studies (e.g., Bergmann et al., 2016). In this dissertation, I focus on the differences in the sound patterns of a bilingual’s languages which do not only emerge in the precise phonetic realizations of L1 sounds but also in language-specific distributional patterns that determine the realization of these sound categories in different phonetic contexts. Previous work in L1 attrition is limited to a small set of phonetic properties (especially VOT, e.g., Flege, 1987), variables beyond L2 transfer which are known to give rise to variable realizations have been neglected. Thus, little is known as to whether bilinguals’ realizations of an L1 sound category in different phonetic contexts (e.g., position within a syllable) are subject to change in L1 attrition, and whether such changes arise due to long-term exposure to different distributional patterns of an equivalent L2 category. In this dissertation I address these gaps by exploring L1 attrition in the distributional and phonetic characteristics of liquids to shed light on the contribution of the L2 and the role of general phonetic and phonological variables to the processes that drive change in an L1. I investigate changes to phonetic properties and distributional patterns of rhoticity and /l/-allophony in the L1 of American-German late bilinguals, a language constellation which offers an instructive test case to investigate the causes of L1 attrition as well as the source from which changes due to L1 attrition emerge. Furthermore, changes to liquids can also shed light on the processes which drive sound change, gradience and variability due to various positional and phonetic factors (e.g., preceding vowel, syllable structure) in liquids across many native varieties of English. In particular, I explore the variable realization and distributional patterns of two sounds known to be subject to a considerable degree of gradience and variability, namely English /r/ and /l/, in American English-German late bilinguals. To that end, I present the results of a production study of 12 L2-dominant American English-German late bilinguals as well as a monolingual control group for each language. The speakers performed a variety of production tasks which were aimed to elicit the realization of (non)-rhoticity and /l/-(non-)allophony in both languages of the late bilinguals, English and German which were analyzed auditorily (/r/ only) and acoustically (/r/ and /l/). Although L1 attrition of rhotics and laterals has been investigated previously (e.g., de Leeuw, 2008; Ulbrich & Ordin, 2014), the effect of contextual variables on L1 attrition and whether such variables also shape L1 attrition remains unexplored. The results of the auditory analyses of postvocalic /r/ revealed that the late bilinguals showed non-convergence with monolingual (non-)rhoticity in both of their languages by vocalizing postvocalic /r/ more frequently in their L1 (English) and failing to entirely suppress rhoticity in their L2 (German) leading up to a higher degree of rhoticity in their L2. While the loss of rhoticity in the bilingual’s English was distributed along a spectrum of contextual constraints (e.g., type of pre-rhotic vowel and morpho-phonological environment) known to affect rhoticity in other English varieties, the non-targetlike productions of non-rhoticity (i.e., non-vocalized postvocalic /r/) in their L2, German, were not sensitive to the same contextual constraints. The acoustic analyses of the bilinguals’ rhotic productions in English and German differed from the monolinguals in the acoustic correlates of rhoticity in pre-rhotic vowels where they showed reduced anticipatory F3-lowering (i.e., less /r/-colored vowels). I take my results to indicate that the bilinguals operate in two separate phonological grammars which approximate the respective L1 norm but show an increase of variability along constraints already present in each grammar. In contrast, the bilinguals’ phonetic system seem shared between the two grammars. This leads to persistent L1-L2-interactions as the two grammars operate within the same phonetic space. Thus, the changes in L1 attrition are induced but not governed by the L2: Change to the L1 reflects constraints underlying the L1 as well as more general laws of phonetics and universal trajectories of language change. The lateral results revealed that just like in postvocalic /r/, the bilinguals showed non-convergence with the monolingual norm regarding the velarization of coda /l/ in both their languages. The changes to English laterals were sensitive to their positional context and more substantial for word-initial laterals than word-final laterals. Similarly, their German laterals were non-convergent with the monolinguals in two ways. Firstly, the bilinguals differed with regard to the acoustic specifications of their laterals, and secondly, the bilinguals failed to suppress the lateral allophony from their L1, leading to a non-targetlike allophonic pattern in their L2 laterals. I interpret the lateral results to lack evidence that the L1 allophonic rule was affected by the presence of an L2; nevertheless, L1 change emerged in the phonetic specifications of laterals. Furthermore, the bilinguals did not establish a nativelike allophonic pattern in their L2, leading to non-convergence in the allophonic distribution as well as the phonetic realization of German laterals. In this way, this dissertation provides evidence for L1 attrition in the distributional and the phonetic properties of liquids in the L1 of late bilinguals. In particular, the study presented in this dissertation provides evidence that L1 attrition is induced by the presence of a similar sound pattern in the L2. The pathway of attrition follows constraints not only underlyingly present in the L1 but also part of the universal laws of phonetics known to shape sound change. To explain these results, I draw from existing constraint grammars in phonological theory (such as Optimality Theory and Harmonic Grammar) to develop my Dynamic Constraints approach which allows the effects of external variables (e.g., L2 acquisition and its effect on the mind), and internal variables such as an increased likelihood of variability due to articulatory differences can be modeled using scaling factors which can interact with each other, the noise within the grammars, and the constraint weight itself. In this way, the model links previous findings on L1 attrition and its connections to diachronic and synchronic variability, offering insights into the links between the individual languages in a bilingual’s mind. / Bis heute hat eine Vielzahl von Studien zum Spracherwerb im Erwachsenenalter gezeigt, dass sich die phonetischen Merkmale der Muttersprache (L1) und Zweitsprache (L2) gegenseitig beeinflussen. Durch den Einfluss der L1 auf die Lautbildung in der L2 weichen insbesondere späte L2-Lerner von der L1 Norm ab. Modelle zum Erwerb von Lautmerkmalen in einer Zweitsprache wie zum Beispiel das Speech Learning Model (SLM) von Flege (2007) erklären den starken Einfluss der L1 im Spracherwerb im Erwachsenenalter anhand einer Eingliederung des Lautsystems der L2 in den bereits bestehenden phonetischen Raum der L1. Die dadurch entstandene Verknüpfung zwischen der L1 und der L2 führten nicht nur zum Einfluss der L1 auf die L2, sondern wie durch das SLM vorgesagt und durch neuere Studien gezeigt (z.B. DeLeeuw, Mennen & Scobbie, 2004; Chang, 2012), auch zu Veränderungen der L1 Lautkategorien. Diese nähern sich hierbei an die Ziellaute der L2 an, ein Prozess der als Spracherosion bezeichnet wird. Über das genaue Fortschreiten und die Gesetzmäßigkeiten des Einflusses der L2 auf die L1 ist jedoch wenig bekannt. In der bisherigen Forschung wurden Veränderungen in der L1 durch Transfer von der L2 in die L1 erklärt; jedoch zeigt sich bei genauerer Betrachtung vorheriger Ergebnisse, dass die L2 allein nicht ausreicht, um die beobachteten Veränderungen vollständig zu erklären. In meiner Dissertation befasse ich mich mit Prozessen der Spracherosion, welche sich nicht nur in den konkreten phonetischen Realisierungen von Lauten der L1 später bilingualer Sprecher äußern, sondern auch in den Verteilungsmustern von konkreten positionsspezifischen Lautvarianten. Die Forschung zur Spracherosion in der L1 beschränkte sich bislang auf eine kleine Anzahl von phonetischen Merkmalen, insbesondere VOT (z.B. Flege, 1987), und erklärte Veränderungen vollständig über die Merkmaleigenschaften der L2. Im Gegensatz hierzu ist der Beitrag anderer Faktoren jenseits des L2-Transfers zur Spracherosion weitestgehend unerforscht. Daher ist aktuell wenig bekannt, ob zweisprachige Realisierungen einer L1-Lautkategorie in verschiedenen phonetischen Kontexten (z. B. Position innerhalb einer Silbe) ebenfalls von Erosionserscheinungen betroffen sein können. Ebenfalls ist der Grund für solche Veränderungen unbekannt. In meiner Dissertation schließe ich diese Lücke, indem ich untersuche, wie Veränderungsprozesse der Spracherosion in den Verteilungs- und phonetischen Merkmalen wirken. Zu diesem Zweck untersuche ich Veränderungen phonetischer Merkmale sowie der Verteilungsmuster von L1-Rhotizität und /l/-Allophonen bei späten Amerikanisch-Deutschen Bilingualen. Zu diesem Zweck präsentiere ich mein Ergebnis einer Produktionsstudie von zwölf L2-dominanten Amerikanisch-Deutsch-Spätsprachlern sowie einer einsprachigen Kontrollgruppe zur jeweiligen Sprache. Die Proband*innen führten eine Vielzahl von Produktionsaufgaben, die darauf abzielten, die (Nicht-) Rhotizität und /l/-Allophonie in beiden Sprachen (Englisch und Deutsch) zu evaluieren. Diese habe ich in dieser Arbeit auditiv analysiert (nur /r/) und akustisch (/r/ und /l/) ausgewertet. Obwohl der Verlust von Rhotischen und Lateralen in der L1 bereits untersucht wurde (z. B. de Leeuw, 2008; Ulbrich & Ordin, 2014), blieb der Effekt von linguistischen und nicht-linguistischen Variablen auf den Erstsprachverlust bisher unerforscht. Das Ergebnis der auditorischen Analyse von postvokalischen /r/ zeigt, dass die späten Bilingualen von monolingualen Sprechern beider Sprachen abweichen. Im Englischen realisierten die Bilingualen das postvokalische /r/ häufiger in der L2-ähnlichen (vokalisierten) Variante und zeigten Reste von konsonantischen Realisierungen in der eigentlich nicht-rhotischen L2. Während der Verlust der Rhotizität in der L1 der Bilingualen (Englisch) von kontextuellen Beschränkungen (z. B. Art des vorrhotischen Vokals und der morphophonologischen Struktur der Silbe) geprägt war und differentielle Verteilungen über die Kontexte hinweg zeigte, waren die Bilingualen in ihrer L2 (Deutsch) nicht empfänglich für kontextuelle Variation, wie es auch in monolingualen Sprechern des Deutschen erwartet wird. Die akustischen Analysen zeigen, dass rhotische Produktionen der zweisprachigen Sprecher im Englischen und Deutschen sich deutlich von denen der monolingualen Kontrollgruppen unterscheiden: Hier wichen die späten Bilingualen vor allem in der Produktion antizipatorischer Rhotizität ab und produzierten die vorrhotischen Vokale mit weniger rhotischer Färbung. Ich interpretiere meine Ergebnisse als Beleg, dass die bilingualen Sprecher in zwei getrennten phonologischen Grammatiken für ihre Sprache arbeiten, die jeweils der L1-Norm entsprechen, jedoch einen höheren Grad an Variabilität zeigen. Diese Variabilität entsteht jedoch nicht durch sprachübergreifenden Transfer, sondern ist beeinflusst von den grammatischen Gegebenheiten der L1. Die phonetische Analyse zeigte im Gegensatz dazu, dass die bilingualen in einem einzigen phonetischen Raum agieren, welchen sich beide Sprachen teilen und wodurch phonetische Wechselwirkungen zwischen beiden Sprachen entstehen. Somit werden die Veränderungen im Zuge der Spracherosion von der L2 induziert, aber nicht von ihr gesteuert. Die Änderungen der L1 zeigt Sprachveränderungen auf, denen die Grammatik der L1 zugrunde liegt, und sind weiterhin geprägt von allgemeinen Gesetzen der Phonetik und des Sprachwandels. Die Ergebnisse der Lateral-Analyse zeigen, dass genau wie in postvokalischen /r/ die zweisprachigen Sprecher nicht mit monolingualen Sprechern konvergent sind. Besonders in Bezug auf die Velarisierung von wortfinalen /l/ in beiden Sprachen unterscheidet sich die bilinguale Gruppe deutlich von Monolingualen. Die festgestellten Änderungen unterlagen hier positionsbedingten Beschränkungen und waren im wortinitialen /l/ deutlich stärker ausgeprägt als im wortfinalen /l/. Weiterhin zeigten die Bilingualen eine stark ausgeprägte Allophonie in beiden Sprachen. Die Ergebnisse der Untersuchungen zu Lateralen liefern jedoch keinen Beleg für einen gleichmäßigen Erosionsprozess, und waren stattdessen stark geprägt von der L1 sowie von universellen Gesetzmäßigkeiten der Lautbildung. Insofern zeigt meine Dissertation, dass Spracherosion nicht einheitlich auf einen Sprecher wirkt, sondern dass Spracherosion einem historischen Prozess des Lautwandels ähnelt, welcher universellen phonetischen und phonologischen Gesetzen folgt. Die Ergebnisse meiner Studie erkläre ich mithilfe von phonologischen Constraint-Grammatiken (insbesondere Optimality Theory und Harmonic Grammar), den ich Dynamic Constraints nenne. In diesem Ansatz modifiziere ich einen Algorhithmus, wodurch linguistische und nicht-linguistische Faktoren das Gewicht von Constraints und die zufällige Streuung von Gewichten beeinflussen können. Hierdurch ergibt sich die Möglichkeit, mit Dynamic Constraints bisherige Forschungsergebnisse im Bereich der Psycholinguistik mit Kenntnissen aus der historischen und sozialen Sprachforschung zu verbinden und einen Einblick in die Sprachsysteme von Bilingualen zu gewinnen.
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Inverse Compton gamma-rays from Markarian 421 : A study of GeV and TeV emission from Mrk 421 based on Fermi-LAT and H.E.S.S. data

Andersson, Tom January 2016 (has links)
This thesis summarizes a senior project on the Active Galactic Nucleus (AGN) Markarian 421 (Mrk 421). Observations of Gev and TeV flux with Fermi Large Area Telescope (LAT) and High Energy Stereoscopic System (H.E.S.S.) were compared with previous reports and publications of flux analyses of the gamma-ray emission from Mrk 421. Power laws with exponential cutoffs made consistent fits to most SEDs in the GeV and TeV bands.

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