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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.
141

Lights, Clock, Action! Circadian Rhythms of Locomotor Activity in Larinioides cornutus Indicate Extreme Flexibility in Photo-entrainment

Miller, Madeleine K, Jones, Thomas C, Moore, Darrell 12 April 2019 (has links)
Circadian clocks are responsible for scheduling many behavioral and physiological processes to occur at the most appropriate time of day. The resulting daily rhythms also synchronize (entrain) to external environmental cues, known as zeitgebers. This phenomenon of entrainment enables organisms to anticipate daily changes in environmental conditions such as sunrise/sunset, temperature variations, availability of prey, etc. Given the critical nature of entrainment to survival, it is no surprise that the mechanism is conserved across taxa. The misalignment of the intrinsic clock with the external environment results in a plethora of negative consequences, made apparent by studies involving shift work and jet lag. The focus of the present study is to investigate the chronobiology of Larinioides cornutus (Araneidae), a nocturnal orb-weaving spider, with an emphasis on its entrainment to light:dark cycles. Because spiders have received scarce attention with respect to their chronobiology, it is instructive to compare the properties of spider circadian systems with those of the more established circadian model systems, such as Drosophilaand Murines. We found that both lights-off and lights-on are equally influential zeitgeber cues for (determines the phasing of) both activity onset and offset. Locomotor activity typically begins within a half hour after nightfall, continues throughout the night, and ceases just prior to dawn. Phase shifting experiments show that these spiders can re-entrain within 2 days to a light/dark cycle shifted by 6 hours, and within 3 days when shifted by 12 hours. These rates of re-entrainment occur at an extremely accelerated rate compared to mammals, which readjust to a time shift at a rate of around 1 day/ 1 hour of phase shift. In other words, spiders have a minimal jet-lag response. This suggests an increased level of plasticity in the spider circadian clock that has yet to be observed in other organisms. Typical of circadian rhythms in nearly all organisms, activity also persisted (free-runs) under constant conditions. However, in constant darkness (DD), a drastic change in periodicity was revealed in 66% of individuals, from 23.4 to 25.2. This particular phenomenon is rare and likely indicates the possible interaction of multiple oscillators. Further evidence to support this interpretation is the consistent periods of the rhythm displayed before and after the change. In contrast, under constant light (LL) conditions, 65% of spiders were arrhythmic, with 4 individuals ceasing activity completely. Significant periods detected in LL were normally distributed over an unusually broad range, from 16.7 to 34.9 hours, suggesting a high sensitivity to light. Because of the unusual rates of re-entrainment to light/dark cycles, the spontaneous changes in free-running period under DD, and arrhythmicity in LL, we propose that spiders are valuable comparative model organism for elucidating fundamental mechanisms of circadian clocks.
142

Essays in Applied Microeconomics:

Ferri, Benjamin January 2022 (has links)
Thesis advisor: Donald Cox / This dissertation consists of three related chapters. A unifying feature throughout all is a focus on the role of regional earnings distributions, especially at the Commuting Zone level, in driving social and economic behavior. The first chapter examines the role of women's and men's expected earnings, across Commuting Zones, in driving women's and men's location choices (migration). The second chapter, a collaboration with Lia Yin, examines the roles of the upper and lower tails of the earnings distribution in driving crime rates, with a key distinction made between crimes motivated primarily by emotional gain, and those motivated by financial gain. Both chapters one and two use simple structural models, identified by Shift-Share (Bartik) instruments as instrumental variables. The third chapter delves into the history, meaning, and scope of Shift-Share instruments, develops several new variants, and tests them in an application to measuring effects of earnings inequality single parenting rates. The first chapter, "How Women and Men Choose Where to Live Based on Each Other's Expected Earnings," considers how the distribution of earnings between genders may influence the distribution of the population via internal migration. Might the earnings potential of prospective spouses drive migration choices? Migrants who flock to places with high-earning prospective partners can cause sex ratios to become unbalanced. Shortages of men have been shown to increase rates of single parenting, and shortages of women to increase crime. Past attempts to answer this question have been limited to brief windows in time, and have lacked causal identification. I build a 7-decade panel of U.S. Commuting Zones from Census and American Community Survey data, computing gender-specific Shift-Share (Bartik) instruments in order to isolate exogenous variation in women's and men's expected earnings. I find that both women and men place at least twice as much priority weight on men's expected earnings as they do on women's, indicating a gender asymmetry in preferences. This asymmetry slightly erodes over time from 1970 to 2019, consistent with a shift in norms. Because women and men prioritize men's earnings over women's by about the same amount, gender differences in earnings play little role in driving sex ratio imbalance. However, women place more weight than men do on the sum of women's and men's earnings, so that the ratio of women to men increases by about 1% per 10% increase in earnings. More balanced sex ratios may follow from policies that reduce overall (gender neutral) inequality, such as between urban and rural areas. The second chapter, "The Distinct Roles of Poverty and Higher Earnings in Motivating Crime," considers how the two extremes of the earnings distribution bear upon people's propensity to turn to crime. Does inequality lead to more crime? We develop a new model that articulates how Poverty (the lower tail of the earnings distribution) and Earnings (the upper tail) enter into equilibrium crime rates. In our model, individuals in Poverty have less to lose in the context of criminal punishment, so are less averse to committing crimes in general. The presence of high Earnings (therefore things worth stealing) heightens the expected gain to offenders per crime - but specifically in terms of financial gain, not emotional gain. We estimate our model on a comprehensive panel of U.S. Commuting Zones (1980-2016), deploying novel Shift-Share instruments to correct for reverse causality (of crime on the earnings distribution). Corroborating our hypothesis, we find that high Earnings plays a much larger role in driving crimes that yield financial gain to the offender (various forms of theft) than it does for crimes of emotional gain; while Poverty is a driving force equally across both types of crime. In each case, not accounting for reverse causality would underestimate both effects, often by more than double. The third and final chapter, "Novel Shift-Share Instruments and Their Applications," digs deeper into the topic of Shift-Share (Bartik) instruments, which are vital in both of the earlier chapters. Shift-Share instruments are among the most important tools for causal identification in economics. In this paper, I crystallize main ideas underlying Shift-Share instruments - their core structure, distinctive claim to validity as instruments, history, uses, and wealth of varieties. I argue that the essence of the Shift-Share approach is to decompose the endogenous explanatory variable into an accounting identity with multiple components; preserve that which is most exogenous in the accounting identity, and neutralize that which is most endogenous. Following this framework, I show clearly how several variants in the literature are related. I then develop formulas for several new variants. Particularly, I show how to develop Shift-Share instruments for distribution summaries beyond the mean - the variance, skew, absolute deviation around a central point, and Gini coefficient. As an empirical application that highlights the themes of the paper, I measure the effect of earnings inequality on rates of single parenting in the U.S., comparing results using each of various alternative instruments for the Gini coefficient. / Thesis (PhD) — Boston College, 2022. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Economics.
143

Two types of clinical ictal direct current shifts in invasive EEG of intractable focal epilepsy identified by waveform cluster analysis / 難治部分てんかん患者の侵襲的脳波を用いたクラスター分析によって同定された発作時直流緩電位変化の2分類

Kajikawa, Shunsuke 24 November 2022 (has links)
京都大学 / 新制・課程博士 / 博士(医学) / 甲第24282号 / 医博第4898号 / 新制||医||1061(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 伊佐 正, 教授 花川 隆, 教授 村井 俊哉 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM
144

Phase Shift Approximation to Reaction Matrix Elements in an Oscillator Representation

Jopko, A. M. 09 1900 (has links)
<p> This thesis presents a derivation of a method to obtain two-body, diagonal and non-diagonal, reaction matrix elements for central and tensor forces respectively directly from nucleon-nucleon scattering phase shifts. This procedure eliminates the necessity for constructing a nuclear potential.</p> / Thesis / Master of Science (MSc)
145

APPLICATION OF THE MEAN SHIFT ALGORITHM ON CLUSTERS OF ORTHOLOGOUS GROUPS AND PHYLOGENETIC IMPLICATIONS

MAHAJANI, RASIKA January 2005 (has links)
No description available.
146

The Association of Types of Shift Work and Food Security Status among Overweight and Obese U.S. Adults aged 20-79, NHANES 2005-2010

Eggerichs, Jennifer J. 15 October 2015 (has links)
No description available.
147

NMR LINE SHAPES AND KNIGHT SHIFTS OF NaxCoO2-YH2O

Ning, Fanlong 12 1900 (has links)
<p> We investigated the local electronic properties of the triangular-lattice materials NaxCO2 (x = 0.3, 0.72) and the superconductor Na0.3Co02-1.3H20 by 59Co and 170 Nuclear Magnetic Resonance(NMR). For Na0.72Co02 , 59Co NMR line shape shows clearly that there are two types of Co sites - Co(A) site and Co(B) site. The electronic character of Co(A) site is close to that of the less magnetic Co+3-like ion with spin rv 0, while the electronic character of Co(B) site is close to that of the strongly magnetic Co+4-like ions with spin ~ 1/2. The temperature dependence of the Knight shifts suggests that the Co(A) and Co(B) sites are electronically coupled, which is not consistent with simple phase separation. The local Co electronic environments propagate to the adjacent 0 layers through p-d hybridization. Therefore, there are two types of oxygen sites, O(A) site and O(B) site. We introduced a different route to do K vs x plot analysis for the Co sites and determined that for the Co sites, Karbitat(A) is 1.816 % and Kspin(A) is about rv 0.2 %; Karbitat(B) is 4.0255 % and Kspin(B) is at least 1.5 %. For Na0 .3Co02 , 59Co NMR line shape shows that the Co valence is averaged out in this material. There are two types of oxygen sites, 0( C) site and O(D) site, presumably because of the nearest neighbor Na+ sites. The constant behavior of Knight shifts below 100 K for both the Co and 0 sites suggests the emergence of a low temperature canonical Fermi-liquid behavior. For the superconductor Na0.3CoO2-1.3H20, both 59Co and 170 NMR line shapes show that there is only one type of Co site and oxygen site. The Knight shifts of 59Co and 170 are temperature independent below 100 K down to Tc. Combined with our spin-lattice relaxation 1/T 1 T measurements, we can rule out the possibility of ferromagnetic scenario of spin excitations above Tc. </p> / Thesis / Master of Science (MSc)
148

Transformed by the renewing of our minds: shifting ecclesial mindsets in Northwestern Pennsylvania

Hall, Melinda 25 April 2024 (has links)
Centered in the Diocese of NWPA, this thesis proposes a diocesan-level curriculum that will help struggling, timeworn Episcopal parishes grow into thriving, contextual Episcopal communities based in methods of transformative learning, particularly strategies that engage spirituality (Tisdell and Tolliver), undo oppressive frameworks (Freire), and teach organizations to learn (Senge). The desired outcome is shifted mindsets around church and the Episcopal tradition so that these parishes live into their unique callings to proclaim the gospel. This paper reflects on the demographic and ecclesial challenges, setting the context for the work to be done, before exploring the characteristics of vibrant parishes in this region. The middle part of the thesis develops the curriculum, particularly exploring its scholarly grounding, before concluding with effective tools for measuring the success of the program in shifting mindsets.
149

High Precision Dynamic Power System Frequency Estimation Algorithm Based on Phasor Approach

Zhang, Xuan 11 February 2004 (has links)
An internet-based, real-time, Global Positioning System (GPS) ---synchronized relative to the wide-area frequency-monitoring network (FNET) ---has been developed at Virginia Tech. In this FNET system, an algorithm that employs the relationship between phasor angles and deviated frequency [13] is used to calculate both frequency and its rate of change. Tests of the algorithm disclose that, for non-pure sinusoidal input (as compared to pure sinusoidal input), significant errors in the output frequency will result. Three approaches for increasing the accuracy of the output frequency were compared. The first---increasing the number of samples per cycle N---proved ineffective. The second---using the average of the first estimated frequencies rather than the instant first estimated frequency as the resampling frequency---produces a moderate increase in accuracy of the frequency estimation. The third---multiple resampling---significantly increased accuracy. But both the second and the third become ineffective to the extent the input is not pure sinusoidal. From a practical standpoint, attention needs to be paid toward eliminating noise in the input data from the power grid so as to make it more purely sinusoidal. Therefore, it will be worthwhile to test more sophisticated digital filters for processing the input data before feeding it to the algorithm. / Master of Science
150

Prototyp av växelspaksknopp CMG3 / Prototype of a gear knob CMG3

Corselli, Rebecca, Al-Shawi, Sajjad January 2016 (has links)
This study has taken place in Mullsjö at Kongsberg Automotive (KA). The purpose of the study was to evaluate how to construct an easy mountable gearknob to the lowest cost based on design and functionality by using the techniques of concept generation and sifting. The knob is intended to be integrated in a Shift-ByWire shifter and generate prototypes through SLS. Researchers followed a concept study methodology following an abductive approach, to generate an appropriate mechanical design for the gearknob. Concepts were formed by a brainstorming process, followed by weighing criteria for the knob and were finalised by evaluating the formed concepts using a Pughs Matrix constructed by the researches. Relevant literature of mechanical designs processes was reviewed to develop the theoretical framework. In addition, data was collected from Kongsberg´s computer system and unstructured interviews with employees within certain specific areas to gain additional understanding. In cooperation with supervisors, pros and cons analysis of cost, functionality and mounting capability were used to enable the researchers to draw recommendations for mechanical designs meeting the requirements of specification. The study resulted in several findings in relation to each research question. In general, a gear knob has been constructed using SLS that can be both used for mounting and demounting purposes. In addition, this construction met the specification of requirements by KA. The Printed Circuit Board (PCB) were constructed using the geometrics in the inherent components of the knob. The study further resulted in a leather gaiter that were constructed as a link between the dashboard and the knob. Results from this study imply that more screws would be used for mounting different components in the prototype phase, which will impact the view on criteria for forthcoming knobs and their mounting methods. In addition, data collection have also shown that snaps in chromium details easily break, which can also further question the use of chromium snaps for dismantling purposes. Finalised recommendations for the gearknob met the requirements of specification since researchers constructed the most simple mounting on the current surface design. Researchers conclude that these concepts are applicable and could be presented in a following prototype phase. However, if the knob is to be produced, researchers do not have enough support regarding the liquid injection moulding, which requires to be further considered. Materials will require the design constructed in this study to be modified. / Arbetet har skett i Mullsjö på Kongsberg Automotive (KA). Syftet med studien var att konstruera en lättmonterad växelspaksknopp till lägsta kostnad utifrån design och funktionalitet. Detta baserat på konceptgenerering och sållningstekniker. Knoppen kommer att integreras i en Shift-by-Wire växelspak och tillverkas i SLS prototyper. Arbetet är en konceptstudie som har följt en abduktiv ansats. Tidigare konstruktionslösningar har studerats för att få kunskap om hur en knopp utformas. Koncepten har genererats via brainstorming och har följts upp av parvis viktning. Koncepten har sedan sållats med hjälp av Pughs matris. Relevant litteratur inom produktutvecklingsprocesser samt intervjuer med anställda har gett grunden till det teoretiska ramverket. Handledare har givit sin input under hela arbetsprocessen för att hjälpa studenterna att välja rätt koncept utifrån monterbarhet, funktionalitet och pris. Studien har svarat på de tre frågeställningarna som utformats. En knopp i SLS har konstruerats utifrån enkel montering och demontering som möter företagets kravspecifikation. Kretskorten inuti knoppen har formats utefter de ingående delarnas geometrier. Vidare har övergången mellan knopp och centerkonsol resulterat i en läderdamask. Studiens resultat kan få konsekvenser i att mer skruv kommer att användas i prototypfasen vid framtida projekt. Detta kan komma att ändra synen på hur viktigt monterbarheten kan vara i kommande knoppar. Informationsinsamling har också visat att snäppen i kromdetaljer lätt går av och detta kan ifrågasätta användningen av dessa. Vid materialval rekommenderas det att se över konstruktionslösningarna då de uppnådda egenskaperna kan avvika. Arbetet har utformat konstruktionen så att det fungerar bra för SLS prototyper men studenterna kan inte garantera att dessa fungerar om komponenterna ska formsprutas.

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