• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 126
  • 114
  • 53
  • 22
  • 22
  • 14
  • 5
  • 5
  • 4
  • 4
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 450
  • 40
  • 39
  • 32
  • 30
  • 27
  • 26
  • 26
  • 26
  • 26
  • 26
  • 24
  • 24
  • 24
  • 22
  • 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.
81

Proteomic Analysis of Mammary Epithelial Cell Development

Conly, Alyssa Kay 01 January 2014 (has links)
In this set of studies, a proteomic approach was used to investigate the protein profile of the mammary epithelial cell (MEC) through different stages of mammary development. The HC11 cell line was used to investigate protein changes between undifferentiated and differentiated MEC, which represent the pregnant and lactating states of the cells. This comparison revealed an interesting differential expression profile underscoring many recognized processes that occur in differentiated MECs, while others unveiled differences between MEC differentiation in vitro and in vivo. Primary MEC were also isolated from virgin, pregnant, and primiparous quiescent mice to compare the virgin state of the cell to the other two stages of development. These comparisons added to a previous dataset of primary isolated MEC and generated data that implied a surprising level of activity in virgin MEC relative to the other stages of development investigated. Differentially expressed proteins in the virgin and primiparous quiescent comparison also added to evidence of persisting changes occurring in the gland after a full term pregnancy that are implicated in the risk for breast cancer development. Data sets generated in the same manner from differentiating MEC were used in the development of a database to help manage the growing list of differentially expressed proteins and aid in the identification of potential interesting patterns of regulation during mammary development and differentiation.
82

Biosynthesis of Various Steroids in vitro by Isolated Adrenal Cells in Primary Aldosteronism, Cushing's Syndrome, and Adrenogenital Syndrome due to Adrenocortical Adenoma

FUNAHASHI, HIROOMI, MIZUNO, SHIGERU 11 1900 (has links)
No description available.
83

Verlustzeitenbasierte LSA-Steuerung eines Einzelknotens

Oertel, Robert, Wagner, Peter, Krimmling, Jürgen, Körner, Matthias 24 July 2012 (has links) (PDF)
Neue Methoden zur Verkehrsdatenerfassung wie die Fahrzeug-Infrastruktur-Kommunikation, der Floating Car-Ansatz und die Videodetektion eröffnen die Möglichkeit, neue Verfahren zur verkehrsabhängigen Lichtsignalanlagensteuerung zu realisieren. In dem Beitrag wird ein Verfahren beschrieben, das aus diesen Quellen Daten in Form von Fahrzeugverlustzeiten direkt zur Steuerung eines Einzelknotens verwendet. Die robuste Ausgestaltung des Verfahrens sorgt dabei dafür, dass auch mit einer lückenhaften Datenlage, wie z. B. aufgrund geringer Ausstattungsraten kommunikationsfähiger Fahrzeuge, angemessen umgegangen werden kann. Mit Hilfe einer mikroskopischen Simulationsstudie wird nachgewiesen, dass das neue Verfahren bei der Qualität des Verkehrsablaufs das gleiche Niveau wie eine traditionelle Zeitlückensteuerung erreicht oder dieses unter bestimmten Bedingungen sogar übersteigt. Mit abnehmender Ausstattungsrate ergibt sich dabei allerdings ein Qualitätsverlust, der ebenfalls mit Hilfe der mikroskopischen Simulation quantifiziert wird und wichtige Erkenntnisse für einen möglichen Praxistest liefert. / State-of-the-art traffic data sources like Car-to-Infrastructure communication, Floating Car Data and video detection offer great new prospects for vehicle-actuated traffic signal control. Due to this, the article deals with a recent approach which uses vehicles’ delay times for real-time control of traffic signals at an isolated intersection. One of the strengths of the new approach is that it can handle also incomplete data sets, e.g. caused by low penetration rates of vehicles equipped with Car-to-Infrastructure communication technology, in an appropriate manner. Based on a microscopic simulation study the high quality of this innovative approach is demonstrated, which is equal or even outperforms the well-known headway-based control. However, a decreasing penetration rate of equipped vehicles means a reduced quality of signals’ control, which is quantified in the microscopic simulation study, too, and provides useful information for tests in the field.
84

Adaptive stepsize control in path tracking for total degree homotopy continuation method

Cheng, Chao-Chun 06 July 2012 (has links)
The theory of solving polynomial systems by homotopy continuation method has been proposed by Garcia, Zangwill and Drexler, and the most typical method in this category is total degree homotpy. The numerical implementation of tracking homotopy curves can be taken as two parts: prediction and correction. In this thesis we compare the performance of several prediction methods in the total degree homotopy, including Runge-Kutta method, Adams-Bashforth method and cubic Hermite method. In addition, we design an adaptive stepsize control algorithm in path tracking, which is based on the information obtained during Newton correction process. The numerical experiment shows that the stepsize control algorithm is quite efficient and reliable in path tracking. In the end we employ the algorithm for solving eigenvalue problems by random product homotopy method
85

Evolution Of Multivariant Microstuctures With Anisotropic Misfit

Bhattacharyya, Saswata 11 1900 (has links)
Many technologically important alloys such as Ni base superalloys and Ti-Al base alloys benefit from the precipitation of an ordered β phase from a disordered α matrix. When the crystallographic symmetry of the β phase is a subgroup of that of the disordered α phase, the microstructure may contain multiple orientational variants of the β phase, each with its own (anisotropic, crystallographically equivalent) misfit (lattice parameter mismatch) with the matrix phase. Examples include orthorhombic precipitates in a hexagonal matrix in Ti-Al-Nb alloys, and tetragonal precipitates in a cubic matrix in ZrO2-Y2O3. We have studied two-phase microstructures containing multiple variants of the precipitate phase. In particular, we have used phase field simulations to study the effect of elastic stresses in a two dimensional system containing a disordered matrix and three different orientational variants of the precipitate phase, with a view to elucidate the effect of different levels of anisotropy in misfit. We consider a two dimensional, elastically homogeneous and isotropic model system in which the matrix (α) and precipitate (β) phases have hexagonal and rectangular symmetries, respectively, giving rise to three orientational variants of the β phase. Therefore, our phase field model has composition (c) and three order parameters (η1, η2, η3) as the field variables.Due to the difference in crystallographic symmetry, the precipitate-matrix misfit strain tensor, ε*, can be anisotropic. ε*maybe represented in its principal form as ε *= (ε xx 0 ) 0 εyy where ε xx and ε yy are the principal components of the misfit tensor. We define t= εyy/εxx as the parameter representing anisotropy in the misfit. In this thesis, we report the results of our systematic study of microstructural evolution in systems with different values of t, representing different levels of anisotropy in misfit: •Case A: t=1 (dilatational or isotropic misfit) • Case B: 0 <t<1 (principal misfit components are unequal but have the same sign) • Case C: t=0 (the principal misfit along the y direction is zero) • Case D: -1 <t<0 (principal misfit components have opposite signs and unequal magnitudes) • Case E: t= -1 (principal misfit components are equal, but with opposite signs; pure shear) In Cases D and E, there is an invariant line along which the normal misfit is zero. In Case D, this invariant line is at ±54.72◦, and in Case E, it is at ±45◦, with respect to the x-axis. Our simulations of microstructural evolution in this system are based on numerical integration of the Cahn-Hilliard and Cahn-Allen equations which govern the evolution of composition and order parameter fields, respectively. In each case, we have studied two different situations: isolated particle (single variant) and many interacting particles (multivariant). Dynamical growth shape of an isolated precipitate In systems with an isotropic misfit (Case A), the precipitate shape remains circular at all sizes. In Cases B and C, the precipitate shape is elongated along the y-axis, which is also the direction in which the magnitude of the misfit strain is lower. In all these cases, the symmetry of the particle shape remains unaltered at all sizes. In contrast, in Cases D and E, the particle shape exhibits a symmetry-breaking transition. In Case D, the precipitate elongates initially along the y direction (i.e. the direction of lower absolute misfit), before undergoing a transition in which the mirror symmetry normal to x and yaxes is lost. In Case E, the particle has an initial square-like shape (with its sides normal to the 11directions) before losing its four-fold rotation axis to become rectangle-like with its long axis along one of the the 11directions. The critical precipitate size at which the symmetry-breaking shape transition occurs is obtained using bifurcation diagrams. In both Cases D and E, the critical size for the dynamical growth shapes is larger than those for equilibrium shapes[1].This critical size is larger when the matrix supersaturation is higher or shear modulus is lower. Microstructural Evolution In all the five cases, the elastic stresses have a common effect: they lead to microstructures in which the precipitate volume fraction is lower than that in a system with no misfit. This observation is consistent with the results from the thermodynamics of stressed solids that show that a precipitate-matrix misfit increases the interfacial composition in both the matrix and the precipitate phase. In systems with isotropic misfit (Case A), the microstructure consists of isolated circular domains of the precipitate phase that retain their circular shape during growth and subsequent coarsening. In Cases B and C with anisotropic misfit with t≥0, the three orientational variants of the precipitate phase are elongated along the directions of lower misfit (y-axis and ±120◦to y-axis). At a given size, particles in Case C (in which one of the principal misfits is zero) are more elongated than those in Case B. Systems with a higher shear modulus enhance the effect of misfit stresses, and therefore, lead to thinner and longer precipitates. When the precipitate volume fraction is increased, these elongated precipitates interact with (and impinge against) one another to a greater extent, and acquire a more jagged appearance. For Cases D and E, each orientation domain is associated with an invariant line along which the normal misfit is zero. Thus, in Case D, early stage microstructures show particles elongated along directions of lower absolute misfit (y-axis and ±120°to y-axis). At the later stages, the domains of the precipitate phase tend to orient along the invariant lines; this leads some of the particles to acquire a ‘Z’ shape before they completely re-orient themselves along the invariant line. In Case E, each variant grows as a thin plate elongating along the invariant line. The growth and impingement of these thin plates leads to a microstructure exhibiting complex multi-domain patterns such as stars, wedges, triangles, and checkerboard. These patterns have been compared (and are in good agreement) with experimental observations in Ti-Al-Nb alloys containing the precipitate (O) and matrix (α2)phases[2]. Since in Case E the sum of misfit strains of the three variants is zero, elastic energy considerations point to the possibility of compact, self-accommodating clusters of the three variants, sharing antiphase boundaries (APBs). Thus, if the APB energy is sufficiently low, the microstructure may consist of such compact clusters. Our simulations with such low APB energy do show triangle shaped clusters with six separate particles (two of each variant)in a self-accommodating pattern. (Refer PDF file)
86

Integrated geological and petrophysical investigation on carbonate rocks of the middle early to late early Canyon high frequency sequence in the Northern Platform area of the SACROC Unit

Isdiken, Batur 18 February 2014 (has links)
The SACROC unit is an isolated carbonate platform style of reservoir that typifies a peak icehouse system. Icehouse carbonate platforms are one of the least well understood and documented carbonate reservoir styles due to the reservoir heterogeneities they embody. The current study is an attempt to recognize carbonate rock types defined based on rock fabrics by integrating log and core based petrophysical analysis in high-frequency cycle (HFC) scale sequence stratigraphic framework and to improve our ability to understand static and dynamic petrophysical properties of these reservoir rock types, and there by, improve our understanding of heterogeneity in the middle early to late early Canyon (Canyon 2) high frequency sequence (HFS) in the Northern Platform of the SACROC Unit. Based on core descriptions, four different sub-tidal depositional facies were defined in the Canyon 2 HFS. Identified depositional facies were grouped into three different reservoir rock types in respect to their rock fabrics in order for the HFC scale petrophysical reservoir rock type characteristic analysis. Composed of succession of the identified reservoir rocks, twenty different HFCs were determined within the HFC scale sequence stratigraphic framework. The overall trend in the HFCs demonstrate systematic coarsening upward cycles with high reservoir quality at the cycle tops and low reservoir quality at the cycle bottoms. It was observed in terms of systems tracts described within the cycle scale frame work that the overall stacking pattern for high stand systems tracts (HST) and transgressive systems tracts (TST) is aggradational. And, the reservoir rocks representing the HST are more porous and permeable than those of TST. In addition to that, it was detected that the diagenetic overprint on the HST reservoir rocks is more than that of the TST. According to the overall petrophysical observations, the grain-dominated packstone deposited during HST was interpreted as the best reservoir rock. Upon well log analysis on the identified reservoir rocks, some specific log responses were attributed to the identified reservoir rocks as their characteristic log signatures. / text
87

Hydrological regime changes in a Canadian Prairie wetland basin

2015 July 1900 (has links)
The hydrology of the Canadian Prairies has been well described in the scientific literature. 20th C observations show that snowmelt over frozen soils accounted for over 80% of the annual runoff, and streamflow hydrographs peaked in April and ceased in May due to a lack of runoff or groundwater contributions. Since then, the region has undergone rapid changes in land use and climate, both which affect streamflow generating processes. This study evaluates the detailed hydrological impact of regional changes to climate on an instrumented research catchment, the Smith Creek Research Basin (SCRB); an unregulated, wetland and agriculture dominated prairie catchment in south-eastern Saskatchewan. Wetlands have been drained for decades, reducing wetland extent by 58% and maximum storage volume by 79%, and increasing drainage channels lengths by 780%. Long term meteorological records show that there have been gradual changes to the climate: though there are no trends in annual precipitation amount, increasing temperatures since 1942 have brought on a gradual increase in the rainfall fraction of precipitation and an earlier snowmelt by two weeks. In the summer months, the number of multiple day rainfall events has increased by 5 events per year, which may make rainfall-runoff generation mechanisms more efficient. Streamflow records show that annual streamflow volume and runoff ratios have increased 14-fold and 12-fold, respectively since 1975, with major shifts in 1994 and 2010. Streamflow contributions from rainfall-runoff and mixed-runoff regimes increased substantially. Snowmelt runoff declined from 86% of annual discharge volume in the 1970’s to 47% recently while rainfall runoff increased from 7% to 34%. Annual peak discharge tripled over the period from 1975 to 2014, with a major shift in 1994, while the duration of flow doubled in length to 147 days after a changepoint in 1990. Recent flooding in the SCRB has produced abnormally large streamflow volumes, and flooding in June 2012 and 2014 was caused solely by rainfall, something never before recorded at the basin. Although the observed changes in climate and wetland drainage are substantial, it is unlikely that a single change can explain the dramatic shifts in the surface hydrology of the SCRB. Further investigation using process hydrology simulations is needed to help explain the observed regime changes.
88

Boundary conditions for black holes using the Ashtekar isolated and dynamical horizons formalism

Schirmer, Jerry Michael 02 February 2011 (has links)
Isolated and Dynamical horizons are used to generate boundary conditions upon the lapse and shift vectors. Numerous results involving the Hamiltonian of General relativity are derived, including a self-contained derivation of the Hamiltonian equations of general relativity using both a direct 'brute force' method of directly computing Lie derivatives, as well as the standard Hamil- tonian approach. Conclusions are compared to numerous examples, including the Kerr, Schwarzschild-De Sitter, McVittie, and Vaiyda spacetimes. / text
89

Physiochemical and Rheological Properties of Alkaline Isolated Poultry Proteins

Moayedi Mamaghani , Vida Unknown Date
No description available.
90

Oplevelseaf isolation under indlæggelse : Et kvalitativt studie / Experience of source isolation during hospitalization : A qualitative study

Madsen, Ann Filippa January 2014 (has links)
Formål: Formålet med dette studie var at undersøge faktorer der kan have betydning for hvordan patienten magter at være isoleret under indlæggelse på hospital. Der søges afdækning af om der er baggrundsvariabler som køn, alder og tidligere erfaringer, som har betydning og hvilke konsekvenser det medfører. Formålet var endvidere på baggrund af en risikoanalyse af den enkelte patientat fokusere på at tilrettelægge organiseringen af pleje og behandling. Metode: Studiet er et kvalitativstudie, hvor det empiriske materiale blev indsamlet ved fempatientinterviews. Som analysemetode blev anvendt indholdsanalyse. Den konceptuelle ramme omfatter antibiotikaresistens i et folkesundhedsperspektiv, en beskrivelse af rammerne for infektionsforebyggelse i Danmark samt en teoretisk ramme af hvad det indebærer for patienter at være smittet med en multiresistent bakterie og oplevelse af at være isoleret. Resultater: Studiet viser, at lukket dør, mangel på kontakt og stimuli resulterer i følelsen af kedsomhed, monotoni og angst. Studiet viser endvidere at baggrundsvariabler synes at have betydning for hvordan isolationen opleves. Kvinder udviser større bekymringer omkring smitteforholdsregler, og er mere observante på personalets adfærd end mænd. Kvinder bekymrer sig mere om risikoen for smitteoverførsel til besøgende og familie. Kvinder er mere emotionelle under indlæggelsen og under isolationen. Mænd affinder sig udadtil med situationen og har ikke samme spekulationer omkring smitteforholdsregler. Mænd har en mere rationel tilgang, og der er en tendens til at mænd bedre magter at være isoleret på enestue. Yngre patienterser ud til at magte isolationen bedre og anser enestue som en fordel. De ældre bliver mere triste og føler sig ensomme. Erindringer fra tidligere indlæggelser kan lejres som negative oplevelser, og influere på nuværende indlæggelse. Forat patienterne kunne magte situationen, udviklede de selv strategier til egen hjælp og befandt sig således i en balance mellem stress og mestring. Konklusion: For at kunne forebygge de negative oplevelser det har for patienter som er isoleret, uden at kompromittere smitteforebyggelsen, vil et skærpet fokus på hele organiseringen, undervisning af personale, tilrettelæggelsen af isolationen med fokus på sengestuefaciliteter, tid til kontakt og grundig information være nødvendig. Her udover kan individuelle foranstaltninger på baggrund af en risikoanalyse overvejes. / Aim: This study explored and describedthe factors that may influence how patients react to source isolation from others during hospitalization. The study also sought to determine how background variables such as gender, age, and previous hospitalization affect source isolation. Based on individuals’ risk assessment, this study also focusedon how hospitalsplan and the organization of care and treatment. Method: This qualitative study used content analysisto reviewd ata collected from interviews with five patients. The conceptual framework describes antibiotic resistance and infection control from a public health perspective and exploredits prevention in Denmark. Thetheoretical framework describe show patients experiencean infection acquired by exposure to drug-resistant bacteria, as well assubsequent source isolation. Results: Thelimited space of an isolation room, including closed doors, lack of contact with people, and few sensory stimuli, resulted in patient boredom, monotony,and anxiety. Moreover, the data showed that background variables affected how patients experience source isolation. Compared with men, women showed greater concern about precautions against infection and greater awareness of staff behavior. Women also worried more about the risk of transmitting bacteria/disease to visitors and familymembers, and display more emotion during isolation. In contrast, men outwardly resigned themselves to the situation and didnot speculate about infection precautions. Men had more rational approach, and tended to cope better when isolated in a single room. Younger patients seemed to have a better coping strategy during isolation, and considered a single room an advantage compared to the ward. Elderly patients felt sad and lonely during source isolation. In addition, previous negative experiences from earlier hospitalization seemedto influence current isolation. Patients developed their own strategies for coping with source isolation and found themselves balanced between being stressed and coping. Conclusion: Hospitals need more alternatives (e.g., better training and improved treatment culture) to prevent negative psychological affects due to isolation without compromising infection prevention. Hospitals should update their personnel at all organizational levels, and focus on room facilities in the ward, contact time,and improved information and communication. Riskassessment should be individualizedfor each patient. / <p>ISBN 978-91-86739-98-0</p>

Page generated in 0.0632 seconds