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Studium vzájemné interakce trhlin šířících se v částicovém kompozitu s křehkou matricí za podmínek subkritického růstu / Mutual interaction of multiple cracks growing in the particulate composite with brittle matrix under conditions of sub-critical crack growthSlávik, Ondrej January 2017 (has links)
In the first part of the submitted diploma thesis, the knowledge in the sphere of the fracture mechanics, related to the practice part of this thesis are summarized. In that the 2D parametrical numerical model of the particle composite with multiple cracks was created, using the finite elements method. Thanks to this model it is possible to find specific configurations which are showing the existance of multiple mutual interactions between these cracks, just by simple manipulation of the input data. In the calculations the influence of the residual stresses was considered which are formed during production of the material. The effect of the subcritical crack growth was taken into account as well in this thesis.
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以優選理論分析上海話之入聲變調 / An OT approach to the Tone Sandhi of checked syllables in Shanghai黃子權, Huang, Tzu Chuan Unknown Date (has links)
本論文以優選理論探討上海話之入聲變調,試圖將文獻中所認為表現不規律之入聲變調納入與舒聲變調相容之分析中。本研究認為入聲變調與舒聲變調皆受制於ANCHOR-L(tσ1, Hd),因此其首音節之基底聲調在輸出值中皆出現於重讀音節。以此觀之,則入聲變調與舒聲變調的差異主要在於節律重音的位置:在舒聲變調中首音節重讀;在入聲變調中重音則後移──在陰入變調中係移至第二音節,在陽入變調中則移至末音節。
本論文提出兩點假設:上海話中舒聲音節為重量音節,入聲音節為輕量音節;節律結構基本上為一位於左端之雙音節音步。據此,本研究提出COINCIDE (LightHd, FT-final),認為陰入變調中重音所以後移至第二音節是因為重讀之輕量音節傾向於由音步末音節核可(licensing)。另一方面,由於陽入的單字調為曲拱調,與陰入的水平調有別,是以本研究另外提出COINCIDE(Contour, PrWd-final),此制約顯示陽入變調中重音的遠距移位是為了遵行「曲拱調須由末音節核可」之普遍現象。
綜述之,本論文提供了一個重量音節、節律重音、曲拱調以及邊際位置等韻律顯著位置間彼此對映的實例。此外,本研究亦顯示上海話的連讀變調涉及聲調與重音的互動,是以所提出之分析或許對相關類型之研究亦有所貢獻。 / This thesis offers an Optimality-theory approach to the tone sandhi of checked tones (TSC) in Shanghai, in an attempt to regulate its surface patterns which have long been considered anomaly as opposed to the tone sandhi of smooth tones (TSS). With a reanalysis in the present study, TSC and TSS arguably have in common that their process of tone mapping is both subject to ANCHOR-L(tσ1, Hd), by which the un- derlying tone of the initial syllable ends up at the stressed syllable in the output. It follows that TSC is different from TSS in the way that metrical head is assigned: all domains undergoing TSS are stressed on their initial syllable; only in domains of TSC does the stress move rightwards, either to the second place in the tone sandhi of Yinru (TSYI), or to the final syllable in the tone sandhi of Yangru (TSYA).
Given the assumption that checked syllables and smooth syllables in Shanghai are light and heavy, respectively, in terms of moraicity, and that foot-parsing is binary and left-aligned in general, the one-syllable shift of stress in TSYI can be accounted for by positing COINCIDE(LightHd, FT-final), which sets up the preference for light stress- bearing syllables to be licensed foot-finally. On the other hand, given that Yangru in the citation forms represents a rising contour, different from the level tone of Yinru, a licensing constraint, namely COINCIDE(Contour, PrWd-final), is further posited so that the long-distance movement of metrical head observed in TSYA emerges to satisfy the requirement for the retained rising contour to be licensed word-finally.
Taken together, this thesis instantiates a remarkable case of the mapping among multiple prominent positions, including heavy syllables, metrical head, contour tones, and edge positions. Also, the present analysis demonstrates that Shanghai tone sandhi involves an interaction between tone and stress, thus a contribution to the general OT tone-prominence typology literature (cf. Zhang 2001, Barnes 2002, De Lacy 2002).
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Behavioral effects of female sex steroid hormones : models of PMS and PMDD in Wistar ratsLöfgren, Magnus January 2009 (has links)
Background Animal models can be used to mimic human conditions of psychopathology, and also as pre-clinical models to evaluate candidate drugs. With hormonal treatment it is possible to produce behavior in the rat which corresponds to the mental symptoms of pre-menstrual syndrome (PMS), and pre-menstrual dysphoric disorder (PMDD). PMS affects 25-30 % of all women in fertile age and 3-8% are diagnosed with the more severe condition PMDD. The cardinal mental symptoms are; irritability, mood-swings, depression, anxiety, fatigue, insomnia, difficulties with concentration and memory and learning difficulties. The symptoms of PMS/PMDD occur in the luteal phase in conjunction with increasing concentrations of progesterone (P4) and P4-metabolites. In anovulatory cycles the symptoms are absent. The hormones which produce the monthly reoccurring negative symptoms on mood are foremost the neuroactive metabolites; allopregnanolone (ALLO) and tetrahydro-deoxycorticosterone (THDOC). ALLO is produced by the corpus luteum, but can also be synthesized in the brain, both ALLO and THDOC can also be released from the adrenal cortex during stress. These steroids are active on the inhibitory GABA neurotransmitter system through the GABAA receptor, and the effects are similar to that of alcohol and benzodiazepines. These steroids have strong sedative and hypnotic effects. A paradox is that some individuals seem to react with negative mood on sex steroids while all fertile women have the cyclical steroid changes during the menstrual cycle. Some individuals are more sensitive to neuroactive steroids with influences of personality, heritability and stress factors. Aims The thesis aims were to develop pre-clinical animal models of PMS/PMDD and to investigate induction of ALLO tolerance, individual sensitivity to neurosteroids and the interactions between chronic social stress and neurosteroids. Methods In these studies male and female Wistar rats were used to test steroid hormone effects on learning and memory and behaviors analogous to negative mood symptoms. This was accomplished through hormonal treatment and a subsequent withdrawal period from P4 (P4) + estradiol (E2) (PEWD), or ALLO. To assess tolerance, memory and learning in the Morris water maze (MWM) was studied. Anxiety-like behaviors were tested with the elevated plus maze (EPM), open field test (OFT), and the intruder test (IT). The EPM or OFT was used to classify the rats as high or low responders on risk-taking and explorative behavior (HR/LR). For social ranking order assessment the tube test (TT) and food competition test (FCT) were used. Chronic social stress was accomplished through co-habituation with two older rats (chronic subordination stress). In female rats the estrous cycle followed using staining of vaginal smears. Concentration of corticosterone (CORT) was measured by radio-immuno-assay (RIA). Results In the MWM ALLO pre-treatment produced tolerance to the acute negative ALLO effects. Both male and female rats showed behavioral correlations between the EPM and OFT tests, and correlations were also seen in CORT levels. Individuals with the stable trait of high risk-taking and explorative behavior (HR) were more sensitive to PEWD induction of anxiety-like behavior. These animals also showed decreased CORT levels during withdrawal. Chronic subordination stress enhanced the response to PEWD on measures of locomotor activity and social anxiety-like behavior. Conclusions It is possible to induce tolerance to the negative ALLO effects on learning and memory. The animal models of anxiety-like behavior show an individual PEWD response profile where HR rats are more sensitive. Exposure to chronic social stress enhanced the PEWD response. Hence there are both inherent and environmental factors behind the behavioral response to steroid hormones in rats. / Stress- och könshormoners verkningar på centrala nervsystemet
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