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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.
321

Traits and habitat specialization influence in future range shifts of butterflies in a warmer climate

Gustafsson, Jennie Frida Linn January 2017 (has links)
Climate change is considered one of the greatest future threats against biodiversity. One predicted consequence of a global temperature increase is that biomes will move against the poles, which will force species to either adapt to an unsuitable habitat or follow their climatic range shift. A common way to assess the future geographical distribution of a species is to predict their future climatic range. However, this excludes factors that could interfere with the species ability to follow their range shift, such as dispersal ability. The importance of expansion-related traits are often assumed rather than quantified. This study investigated if the specialist butterfly Pyrgus armoricanus, living at its northern range limit in south Sweden, will be able to expand north as the temperature increases. The study also explored the importance of six traits on a butterfly’s range shift ability; habitat specialization, growth rate, emigration probability, establishment probability, dispersal vagrancy and dispersal probability. The study found that the butterfly Pyrgus armoricanus will not be able to expand north in Sweden due to low dispersal ability and habitat availability. The most important traits for a butterfly’s ability to expand north in Sweden was growth rate, dispersal ability and habitat generalisation. Specialized butterflies dependent on well managed meadows will have limited success in following their northern range limit, and restoration is necessary to avoid future biodiversity degradation.
322

Validation of an assessment tool for mental fatigue applied to rotational shift work

Huysamen, Kirsten Christina January 2014 (has links)
Mental fatigue has been proven to be highly prominent during shift work, due to long, irregular working hours and disruption of the circadian rhythm. Measuring mental fatigue has been a challenge for many years, where commonly cognitive test tasks are used to assess mental fatigue. Moreover, these test tasks do not isolate where fatigue is occurring during human information processing. The human information processing system consists of four core stages, each of which requires numerous cognitive functions in order to process information. The Human Kinetics and Ergonomics Department at Rhodes University has developed six cognitive test tasks where each isolates a cognitive function: an accommodation test task, a visual detection test task, a reading test task, a memory test task, a tapping test task and a neural control test task. The cognitive functions include: eye accommodation, visual discrimination, visual pattern recognition, memory duration, motor programming and peripheral neural control. General task-related effect can also be examined for each of these cognitive test tasks which include choice reaction time, visual detection, reading performance, short-term memory, motor control and tracking performance. Additionally, a simple reaction time test task has been developed to analyse simple reaction time. This test task does not isolate a cognitive function. One or more parameters can be examined for each cognitive function and task-related effect. The first aim of this study was to validate numerous cognitive test tasks for mental fatigue in a simulated shift work laboratory setting. The second aim was to assess the validated cognitive test tasks in Phase 1 in a field-based rotational shift work setting. Parameters revealing sensitivity to mental fatigue would be validated for mental fatigue applied to rotational shift work and would be inserted into an assessment tool. In the laboratory setting, the seven cognitive test tasks were examined on four different types of shift work regimes. The first regime was a standard eight-hour shift work system, and the other three were non-conventional shift work regimes. Participants (n = 12 per regime) were required to complete one day shift followed by four night shifts, where testing occurred before and after each shift and four times within each shift. The cognitive test tasks revealing sensitivity to fatigue included: visual detection test task, reading test task, memory test task, tapping test task, neural control test task and simple reaction time test task. The testing of Phase 2 was conducted in three different companies, where each performed a different type of rotational shift work. The six cognitive test tasks validated for mental fatigue in Phase 1 were tested before and after work for each shift type within the rotational shift work system adopted by each company. Company A (n = 18) and Company B (n = 24) performed two-shift rotational shift work systems, where the shift length of Company A was 12-hours and the shift length of Company B was irregular hours. Company C (n = 21) performed an eight-hour three-shift rotational shift work system. Nine parameters revealed fatiguing effects and were inserted into the assessment tool, five of which provided information on a specific cognitive function: error rate for visual discrimination, processing time for visual pattern recognition, error rate for visual pattern recognition, impact of rehearsal time on memory recall rate for memory duration and the high-precision condition for motor programming time. The remaining four parameters provided information on general task-related effects: reading speed for reading performance, recall rate for short-term memory, reaction time for motor control and simple reaction time. Therefore, an assessment tool comprising nine parameters was validated for mental fatigue applied to rotational shift work, where five of the parameters were able to isolate exactly where fatigue was occurring during human information processing and the other four parameters were able to assess fatigue occurring throughout the human information processing chain.
323

Lifetimes of states in 19Ne above the 15O+ alpha threshold

Subramanian, Mythili Myths 11 1900 (has links)
Astrophysical models that address stellar energy generation and nucleosynthesis require a considerable amount of input from nuclear physics and are very sensitive to the detailed structure of nuclei, both stable and unstable. Radioactive nuclei play a dominant role in several stellar environments such as supernovae, X-ray bursts, novae etc. and nuclear data are important in the interpretation of these phenomena. When carbon, nitrogen and oxygen isotopes are present in substantial quantities in a star of sufficient mass, the fusion of four hydrogen nuclei to form a helium nucleus proceeds via the CNO cycles. Energy release in the CNO cycles is limited by the long lifetimes of 14O and 15O. In explosive stellar scenarios such as X-ray bursts, the energy output is very large, suggesting a breakout from the CNO cycles. 15O(α,γ)19Ne is the first reaction that breaks out of the CNO cycle. Nuclear structure information on high lying states in 19Ne is required to calculate the rate of the 15O(α,γ)19Ne reaction. This work focuses on the study of states in 19Ne above 3.53 MeV. The lifetimes of five states in 19Ne above 3.53 MeV were measured in this work. The states in 19Ne were populated via the 3He(20Ne,α)19Ne reaction at a beam energy of 34 MeV. The lifetimes were measured using the Doppler Shift Attenuation Method. The lifetimes of five states were measured and an upper limit was set on the lifetime of a sixth state. Three of the measurements are the most precise thus far. The lifetimes of the other three states agree with the values of the only other measurement of the lifetimes of these states. An upper limit on the rate of the 15O(α,γ)19Ne reaction was calculated at the 90% confidence level using the measured lifetimes. The contributions to the 15O(α,γ)19Ne reaction rate from several states in 19Ne at different stellar temperatures are discussed. / Science, Faculty of / Physics and Astronomy, Department of / Graduate
324

Illinois’s Shift to the Left: How a Bellwether State Diverged from National Trends

Segal, Jack 01 January 2018 (has links)
Throughout the 20th century, Illinois supported winning candidates in twenty-three out of twenty-five presidential elections. However, in the 21st century, Illinois supported winning candidates in two out of five presidential elections. The state’s divergence from national trends followed three partisan shifts that occurred in the mid-to-late 20th and early-21st centuries. These shifts altered the state’s partisan preferences. While the causes of each shift varies, Illinois’s changing demographics, the concentration of its population in the Chicago Metropolitan area, and the rise of the post-industrial economy, caused the state to depart national trends as Illinois increasingly supported Democrats.
325

Arbetsrelaterad stress och utmattning : En kvantitativ studie om skillnader mellan män och kvinnor

Bengtsson, Jessica, Pless, Maria January 2017 (has links)
Stressrelaterade besvär och andra former av psykisk ohälsa orsakade av arbetet, är ett omdiskuterat och väl undersökt samhällsfenomen som ökat de senaste åren i Sverige. Några av de vanligaste stressrelaterade besvären är utmattning och trötthet. Forskning har visat att det existerar könsskillnader i upplevelse av stress och att olika typer av arbeten genererar olika stressnivåer hos individer. Syftet med uppsatsen är att bidra med kunskap om stress och utmattning inom arbetslivet, med särskilt fokus på skillnader mellan män och kvinnor. Krav- och kontrollmodellen lyfts fram för att förklara sambandet mellan krav och kontroll i arbetet, vilket ger en förståelse för hur graden av kontroll de anställda har påverkar effekterna av de psykiska krav som den anställde utsätts för. Även Arlie Hochschilds teori om The Second Shift presenteras, för att beskriva hur män och kvinnor på olika sätt utsätts för krav och kontroll i hemmet. Teorierna lyfts fram för att de kan bidra till en förståelse för eventuella könsskillnader i arbetsrelaterad stress och utmattning. En kvantitativ metod har använts för undersökningen av uppsatsens syfte. Det empiriska materialet som används grundar sig på en enkätstudie från 2005, som är hämtad från International Social Survey Programme. Motiveringen till att detta material används som underlag i denna studie är att det kan bidra till en förståelse för respondenternas upplevelse av stress och utmattning, samt för att kunna jämföra skillnader mellan män och kvinnor i dessa avseenden. Resultatet av undersökningen visade att det i vissa fall existerar skillnader mellan män och kvinnor gällande upplevelse av stress och utmattning. Detta resultat visade sig vid undersökningen av alla respondenter som arbetar och av alla heltidsarbetande respondenter som arbetar med människor. Dock visade resultatet att det inte fanns några signifikanta könsskillnader gällande upplevelse av stress, vid undersökningen av alla heltidsarbetande respondenter och de heltidsarbetande respondenter som inte arbetar med människor. Detta tyder på att vidare forskning bör fortsätta undersöka könsskillnader gällande stress och utmattning, eftersom resultatet kan tolkas som att det i nuläget inte går att dra generaliserande slutsatser i detta avseende.
326

Urban street design in modern China : standards, practices and outcomes

Zhang, Yi January 2013 (has links)
This thesis investigates and discusses the current design approaches and development trends of urban streets in China. As the methodological focus, multiple case studies and interviews are used to examine actual street design practice to identify the development policy bias of local governments. Since the 1990s, the great economic achievement in most Chinese cities has evoked significant growth in the number of automobiles, as well as the increasingly serious problems of road casualties and congestion. The traffic-engineering-based design approach which used to be widely adopted and implemented in western countries has dominated the development patterns of urban streets in modern China. The conventional paradigm exclusively focuses on the traffic function in urban streets resulting in morphological changes to the urban circulation environment and keeps on neglecting non-vehicular movement and non-traffic needs. The automobile- dominated urban circulation environment has had negative economic, social and public health impacts. Thus, a paradigm shift which calls for a more inclusive design approach for urban streets which balances functions of place and movement is urgently needed in China. To determine the challenges and opportunities for the new paradigm, this research identifies the cultural, political and technical factors for the traffic-centred design trends and the policy bias. Based on this, policy recommendations and an agenda for revolutionary change for achieving better design practice for urban streets in post-modern China are suggested.
327

Modeling the chemical and photophysical properties of gold complexes.

Barakat, Khaldoon A. 08 1900 (has links)
Various gold complexes were computationally investigated, to probe their photophysical, geometric, and bonding properties. The geometry of AuI complexes (ground state singlet) is very sensitive to the electronic nature of the ligands: σ-donors gave a two-coordinate, linear shape; however, σ-acceptors yielded a three-coordinate, trigonal planar geometry. Doublet AuIIL3 complexes distort to T-shape, and are thus ground state models of the corresponding triplet AuIL3. The disproportionation of AuIIL3 to AuIL3 and AuIIIL3 is endothermic for all ligands investigated, however, σ-donors are better experimental targets for AuII complexes. For dimeric AuI complexes, only one gold center in the optimized triplet exciton displays a Jahn-Teller distortion, and the Au---Au distance is reduced versus the ground state distance (i.e., two reasons for large Stokes' shifts).
328

Rule Utilization and Rule Shift: A Developmental Study

Rakowitz, Lambert William 08 1900 (has links)
Current rule-utilization research indicated that subjects successively tested multiple conceptual rules, available from natural preexperimental experience, to solve a sorting task. Prior results suggested that older subjects were more efficient in utilizing rules and shifting to unused rules, possibly due to the availability of more conceptual rules at higher age levels. The experimental groups consisted of third, fourth, sixth, ninth graders, and college students. Each of the five groups contained 16 subjects. The rule-utilization procedure was applied to each group. The procedure contained a multitrial, card sorting task. The feedback given at the end of each trial was limited to the correctness of the entire card sort and did not provide information on the correctness of the sorting for any individual card. All subjects in each group were run until they used both bidimensional rules (the conjunctive and the inclusive-disjunctive rule), or until a limit of 30 trials was reached.
329

Development of Red-Shifted Channelrhodopsin Variants Having Chemically Modified Retinylidene Chromophore / レチニリデン発色団の化学修飾による赤色光吸収チャネルロドプシンの開発

Shen, Yi-Chung 25 March 2019 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第21610号 / 理博第4517号 / 新制||理||1648(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)准教授 今元 泰, 教授 高田 彰二, 教授 杤尾 豪人 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM
330

An Investigation of the Basis of the Strength-Based Criterion-Shift

Olchowski, James E 29 August 2014 (has links)
In recognition memory, participants often fail to change their criterion for making a “studied” response from one trial to the next based on learning strength, even when they are given obvious cues to identify each test item as studied often (“strong”) or studied a single time (“weak”) (e.g., Stretch & Wixted, 1998). In three experiments we tested the hypothesis that participants produce robust item-by-item shifts only when responding did not involve significant response interference (Simon, Acosta, Mewaldt, & Speidel, 1976). In our three experiments, participants studied lists of words studied once (weak) or five times (strong). In Experiment 1, both strong and weak words appeared at test under the questions “Was this studied at all?” or “Was this studied five times?” Participants were randomly assigned to conditions using two keys to respond “yes” or “no”, or using four keys with one set of “yes” and “no” per question. Four-key participants were expected to shift their criteria while 2-key participants could not due to response interference, though results showed that both conditions were capable of criterion-shifting. In Experiment 2 test items appeared on either the left or the right side of the screen; only strong words appeared on the right and only weak words on the left. Participants went through one study-test cycle with four response keys, and one with two. Regardless of the testing conditions, participants did not shift their criteria in the 2-key condition while participants in the 4-key condition did shift their criteria. Finally, Experiment 3 fully crossed 2 or 4 key conditions with blocked or unblocked presentation of test items. Previous experiments have found both number of response keys and blocking of presentations to have an effect on ability to criterion-shift (Hicks & Starns, 2014; Starns & Olchowski, submitted; Verde & Rotello, 2007). Experiment 3 confirmed that number of response keys has a significant effect on criterion-shifting and that it is separate from any effect of blocking. All three experiments suggest that response interference is not the driving force behind criterion-shifting. A new explanation is proposed.

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