• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 36
  • 12
  • 11
  • 5
  • 5
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 90
  • 21
  • 17
  • 12
  • 10
  • 10
  • 10
  • 9
  • 8
  • 7
  • 7
  • 7
  • 6
  • 6
  • 6
  • 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.
51

Modification of the 20 Metre Shuttle Run Test (20 MST) for ice-sports

Kuisis, S.M. (Suzan Mary) 29 October 2004 (has links)
The 20 Metre Multistage Shuttle Run Test (20 MST) was modified for application to ice-sports, more specifically for ice-hockey and figure-skating. Seventy two participants in ice-sports served as the total subject group. Subjects included in the study were National and Provincial standard male ice-hockey subjects (n=67) and female figure skaters (n=5) participating in the Gauteng area of South Africa (altitude of 1497 metres above sea level and barometric pressure of 655 mmHg). The mean age for the total group was 17.44±1.33 years. The research methodology entailed a repeated measures design to determine: a) velocity of motion on-ice vs. over-ground; b) energy expenditure on-ice vs. over-ground; and c) mechanical efficiency on-ice vs. over-ground. The mean velocity of motion measured over three distances (0 to 20, 0 to 30 and 0 to 40 m) indicated a significantly (p≤0.05) faster velocity on-ice (5.99±0.72 m/s) versus over-ground (5.75±0.63 m/s). The corresponding mean time-lapsed on-ice/over-ground ratio was 0.97±0.11. Differences in mean energy expenditure whilst performing the original 20 MST over-ground as opposed to on-ice were measured at low (at 4 minutes of exercise and 10 km/h), intermediate (after 8 minutes of exercise and 12 km/h), and high intensity (after 12 min of exercise and 14 km/h). The mean of the three indicated a significantly (p≤0.05) higher energy expenditure over-ground (14.04±4.86 kcal/min) as apposed to on-ice (10.51±2.95 kcal/min). The mean energy expenditure ratio for the three different intensities on-ice vs. over-ground was 0.74±0.21. Similarly, the mechanical efficiency index over-ground (4.92±0.59) was found to be significantly (p≤0.001) poorer than on-ice (6.83±1.49). The mean mechanical efficiency ratio over-ground/over-ice was 0.74±0.13. Subsequently, based on the above results, the 20 MST was modified by: a) adapting (increasing) the velocity of motion required for each level of the test (distance of 20 m per shuttle); and b) establishing the reliability and validity of the modified 20 MST for use on-ice. The adapted 20 Metre Multistage Shuttle Skating Test (the modified (skating) 20 MST) started at a velocity of 2.8 m/s (10.1 km/h) and permitted 7.1 seconds to complete each shuttle for the first level of the test, which then decreased progressively at each level. This was based on an over-all variable-derived on-ice to over ground ratio of 0.84. Test-retest, on-ice reliability measures (n=15) for predicted VO2max (49.5±8.37 vs. 49.29±7.95 ml/kg/min) showed a highly significant (p£0.001) consistency (r=0.87). Similarly test-retest concurrent validity measures (n=10) for predicted VO2max over-ground with the original 20 MST (48.09±6.25 ml/kg/min) as designed by Léger and Lambert (1982) versus on-ice values with the adapted on-ice 20 MST (49.98±7.23 ml/kg/min), showed a very significant (p£0.01) correlation of 0.73 between the two tests. In conclusion the original 20 MST, as designed by Léger and Lambert (1982) for over-ground, proved inappropriate for use on-ice. Modification of the starting velocity as well as a progressive increase in velocity for all subsequent stages renders the modified 20 MST for ice-sports a reliable and valid test for cardiorespiratory fitness (VO2max), with surface-specific utility. The 20 Metre Multistage Shuttle Run Test (20 MST) was modified for application to ice-sports, more specifically for ice-hockey and figure-skating. Seventy two participants in ice-sports served as the total subject group. Subjects included in the study were National and Provincial standard male ice-hockey subjects (n=67) and female figure skaters (n=5) participating in the Gauteng area of South Africa (altitude of 1497 metres above sea level and barometric pressure of 655 mmHg). The mean age for the total group was 17.44±1.33 years. The research methodology entailed a repeated measures design to determine: a) velocity of motion on-ice vs. over-ground; b) energy expenditure on-ice vs. over-ground; and c) mechanical efficiency on-ice vs. over-ground. The mean velocity of motion measured over three distances (0 to 20, 0 to 30 and 0 to 40 m) indicated a significantly (p≤0.05) faster velocity on-ice (5.99±0.72 m/s) versus over-ground (5.75±0.63 m/s). The corresponding mean time-lapsed on-ice/over-ground ratio was 0.97±0.11. Differences in mean energy expenditure whilst performing the original 20 MST over-ground as opposed to on-ice were measured at low (at 4 minutes of exercise and 10 km/h), intermediate (after 8 minutes of exercise and 12 km/h), and high intensity (after 12 min of exercise and 14 km/h). The mean of the three indicated a significantly (p≤0.05) higher energy expenditure over-ground (14.04±4.86 kcal/min) as apposed to on-ice (10.51±2.95 kcal/min). The mean energy expenditure ratio for the three different intensities on-ice vs. over-ground was 0.74±0.21. Similarly, the mechanical efficiency index over-ground (4.92±0.59) was found to be significantly (p≤0.001) poorer than on-ice (6.83±1.49). The mean mechanical efficiency ratio over-ground/over-ice was 0.74±0.13. Subsequently, based on the above results, the 20 MST was modified by: a) adapting (increasing) the velocity of motion required for each level of the test (distance of 20 m per shuttle); and b) establishing the reliability and validity of the modified 20 MST for use on-ice. The adapted 20 Metre Multistage Shuttle Skating Test (the modified (skating) 20 MST) started at a velocity of 2.8 m/s (10.1 km/h) and permitted 7.1 seconds to complete each shuttle for the first level of the test, which then decreased progressively at each level. This was based on an over-all variable-derived on-ice to over ground ratio of 0.84. Test-retest, on-ice reliability measures (n=15) for predicted VO2max (49.5±8.37 vs. 49.29±7.95 ml/kg/min) showed a highly significant (p£0.001) consistency (r=0.87). Similarly test-retest concurrent validity measures (n=10) for predicted VO2max over-ground with the original 20 MST (48.09±6.25 ml/kg/min) as designed by Léger and Lambert (1982) versus on-ice values with the adapted on-ice 20 MST (49.98±7.23 ml/kg/min), showed a very significant (p£0.01) correlation of 0.73 between the two tests. In conclusion the original 20 MST, as designed by Léger and Lambert (1982) for over-ground, proved inappropriate for use on-ice. Modification of the starting velocity as well as a progressive increase in velocity for all subsequent stages renders the modified 20 MST for ice-sports a reliable and valid test for cardiorespiratory fitness (VO2max), with surface-specific utility. / Dissertation (MA (Human Movement Science))--University of Pretoria, 2005. / Biokinetics, Sport and Leisure Sciences / unrestricted
52

Untersuchungen an einer Kolbenexpansionsmaschine mit integrierten Wärmeübertragerflächen (Wärmeübertrager-Expander) zur Realisierung eines neuartigen Neon-Tieftemperatur-Prozesses

Fredrich, Ole 23 April 2004 (has links)
Viele Anwendungen der Hochtemperatur-Supraleitung arbeiten vorteilhaft im Temperaturbereich zwischen 30 - 50 K. Für diesen Temperaturbereich existieren nur wenige geeignete Kältemaschinen mit kleiner Kälteleistung (1-2 W) u. gutem Wirkungsgrad. Neon ist aufgrund seiner Stoffeigenschaften ein hervorragendes Kältemittel für diesen Temperaturbereich, wie z.B. anhand einer realisierten Joule-Thomson (JT) Demonstrationsanlage deutlich wird. Als Ergebnis einer Prozessanalyse wird ein Kreislauf vorgestellt, der speziell den Eigenschaften von Neon angepasst ist. Durch die Überlagerung von Wärmeübertragung u. arbeitsleistender Expansion sowie der Einbeziehung einer JT-Stufe kann auch mit wenig effizienten Komponenten ein vergleichsweise hoher Gütegrad erreicht werden. Durch die Integration von Wärmeübertragerflächen in eine Kolbenexpansionsmaschine wird ein neues Konzept vorgeschlagen, um Kälte in einem großen Temperaturbereich in vielen Expansionsschritten zu erzeugen, ohne dafür viele Expander zu verwenden. Diese Einheit wird als Wärmeübertrager-Expander (WE) bezeichnet. Mit einem Arbeitsraum in konischer Grundform wird der Wärmeübergangskoeffizient günstig gestaltet u. die Wärmeübergangsfläche vergrößert. Mehrere Versuchsmaschinen wurden untersucht. Anhand der Versuche konnten die wesentlichen Verlustquellen u. Problembereiche identifiziert werden. Es wurde im Rahmen der Versuchsbedingungen nachgewiesen, dass für das vorgesehene Druckverhältnis eine nahe isotherme Expansion u. Kompression möglich ist. Es werden Möglichkeiten zur Verringerung der Längswärmeleitung vorgestellt. Zwei Simulationsprogramme wurden verwendet. Mit Hilfe des Wärmeübertrager-Programms wurden die Wärmeübertragungsvorgänge unter Berücksichtigung der Längswärmeleitung simuliert. Hierbei geht die Expansionsarbeit als stationäre Wärmesenke ein. Der im Ergebnis vorliegende stationäre Temperaturverlauf ist die Grundlage für die Berechnung der Expansionsarbeit unter Berücksichtigung der Realgaseigenschaften im Expander-Programm. Für die Neon-Tieftemperaturvariante wurde eine Grundvariante des WE definiert. Anhand dieser wurde mit Hilfe der Programme der Einfluss verschiedener Parameter auf Kälteleistung u. Gütegrad untersucht. Der WE wird als Teil des beschriebenen Prozesses mit einer JT-Stufe betrachtet. Die Kälteleistung weist sowohl in Abhängigkeit vom Massestrom als auch vom Hub ein Maximum auf. Der Shuttle-Verlust verschiebt durch Wärmetransport mittels des Kolbens die effektive Kälteleistung zu kleineren Hüben. Die durch die Güte (NTU) des JT-Wärmeübertragers bestimmte Eintrittstemperatur des Niederdruckstroms in den WE hat einen großen Einfluss auf die Kälteleistung. Mit steigender Eintrittstemperatur steigen der NTU-Wert für den Arbeitsraum u. somit auch die Kälteleistung. Das Maximum der Kälteleistung stimmt nicht mit dem Optimum für den Gütegrad überein. Der Gütegrad strebt mit sinkenden Masseströmen einem Optimum zu. Durch den zunehmenden Einfluss der Längswärmeleitung u. begrenzt durch die Minimalfüllung der Maschine aufgrund des Schadraumes ergibt sich ein Optimum. Der Einfluss des Massestroms ist entscheidend. Als untergeordnete Größen beeinflussen die Eintrittstemperatur des Niederdruckstroms u. der Hub den optimalen Gütegrad. Der Einfluss der Längswärmeleitung auf Kälteleistung u. Gütegrad wird exemplarisch anhand von vergleichenden Rechnungen gezeigt. Konkret kann für einen Eintrittsdruck von 200 bar, einen Austrittsdruck von 60 bar bei einer Eintrittstemperatur des Niederdruckstroms von 80 K für die Grundvariante eine maximale effektive Kälteleistung von 1,3 W mit einem Massestrom von 0,22 g/ s bei einem Hub von ca. 17 mm ausgewiesen werden. Der effektive Gütegrad für diese Bedingungen beträgt ca. 14%. Kommerzielle Split-Stirlingkühler erreichen bei 42 K einstufig Gütegrade von ca. 7%. Mit der vorgeschlagenen Konfiguration wird ein Konzept vorgestellt, das trotz technologisch offener Fragen das Gütegradniveau bekannter Kryokühler übertreffen kann. / Many applications of high temperature superconductivity are working advantageously within a temperature range between 30 K and 50 K. But for this temperature range only few suitable cryocooler with small refrigerating capacity (1-2 W) and good efficiency exist.Due to its properties Neon is an excellent refrigerant for this temperature level as an example with realised Joule-Thomson plant shows. A process analysis results in the presented cycle which is especially adapted to the properties of Neon. By combination of heat exchange and work extracting expansion and integration of a Joule-Thomson stage a high efficiency could be reached in spite of less efficient components.By arranging heat exchanger surfaces into a piston expansion machine a new concept is suggested to produce refrigeration in a large temperature range with a lot of expansion steps with reduced number of expanders. This unit is referred hereinafter to as heat exchanger-expander.The conical shaped working space results in an increase of the heat transfer coefficient and the heat transfer area.Several test machines were investigated. By means of testing the main loss sources and critical zones could be identified. The test results prove the opportunity of a near isothermal expansion and compression for the specified pressure ratio.Options to reduce the axial heat conduction are presented.Two simulation programs were utilised. Using the heat exchanger program the heat transfer is simulated in consideration of the axial heat conduction. Thereby the expansion work is considered as a stationary heat sink. The resulting stationary temperature pattern is the base for the expansion work calculation using the real gas properties in the expander program. Referring to the defined basic neon low temperature application the influence of different parameters on refrigerating capacity and efficiency was researched with the programs. The heat exchanger-expander is part of the described process with a Joule-Thomson stage. The refrigerating capacity shows a maximum depending as well from the mass flow as from the stroke. In result of the shuttle loss smaller strokes lead to better capacity due to heat transport with the piston.The inlet temperature of the low pressure flow influenced by the quality (NTU) of the Joule-Thomson heat exchanger has a large influence on the refrigerating capacity. With increasing inlet temperature the number of transfer units (NTU) for the fluid in the working volume increases and so the refrigerating capacity, too. The location of refrigerating capacity maximum and efficiency optimum is different. While decreasing mass flow efficiency is increasing to an optimum caused by the increased influence of axial heat conduction but limited by the minimum charge of the machine due to the dead space. The influence of the mass flow is dominating. As lower range values the inlet temperature of the low pressure flow and the stroke are influencing the optimal efficiency. The influence of axial heat conduction on refrigerating capacity and efficiency is shown using comparing calculations.For an inlet pressure of 200 bar, an outlet pressure of 60 bar, an inlet temperature of the low pressure flow of 80 K, a mass flow of 0,22 g/ s and a stroke of about 17 mm for the basic version of heat exchanger-expander a maximal effective refrigerating capacity of 1,3 We could be shown. The effective efficiency therefore is 14 %. Current commercial split Stirling cryocooler reach with single stage operation efficiencies of about 7 % at 42 K. The suggested configuration represents a concept that could be able to master the efficiency level of known cryocooler.
53

Space Shuttle Program (SSP) retirement and NASA transition to the Vision for Space Exploration (VSE)

Reyes, Carlos Joel 20 September 2010 (has links)
On January 14, 2004, President George W. Bush announced the Vision for Space Exploration (VSE). The goals of the vision include developing a new generation launch capability while completing assembly of the International Space Station (ISS) and retiring the Space Shuttle by 2010. In support of this goal, the Space Shuttle Program (SSP) initiated evaluation of hardware, infrastructure, and workforce skill mix needed to continue Space Shuttle flights until the projected 2010 retirement. The SSP also studied how NASA will deploy personnel from, and use the facilities of, the SSP to ensure that the Space Shuttle operates safely through its final flight, and to ensure personnel and facilities from the SSP are effectively transitioned to NASA’s exploration programs. NASA funding, like other federal agencies, is affected by various factors including domestic and international political environments, current and emerging technologies available to meet agency goals, and sustainability and potential economic return of federal expenditures. In this paper I will present a retrospective analysis of federal budget allocations to NASA as a percentage of the Federal Budget from years 1958 to 2010 (adjusted to 1979 dollars). The classic method for calculating net present value (NPV) is not well suited for projecting potential value of future R&D technologies. A quantitative analysis of R&D technologies transferred to private industry will be presented, as well as a description of a method of evaluating their significance will discussed relative to current budgetary considerations will likely for past, current and upcoming funding cycles. The opportunity at hand for NASA’s transition from SSP to Constellation in support of the VSE initiative is to advocate their culture as R&D innovators and emphasize the future benefit of increased funding. / text
54

Réseaux de capteurs sans fil linéaires : impact de la connectivité et des interférences sur une méthode d'accès basée sur des jetons circulants / Linear Wireless Sensors  Networks : Impact of connectivity and interferences on an Token Based MAC Protocol

Ndoye, El Hadji Malick 21 December 2015 (has links)
Dans cette thèse, il s'agit de proposer un protocole MAC qui prend en compte certaines spécificités des réseaux de capteurs sans fil linéaires. Ce protocole MAC est basé sur des jetons circulants qui donnent aux noeuds le droit d’accès au canal de transmission. Nous évaluons à partir de ce protocole l’impact des interférences et de la connectivité sur un réseau linéaire. Cette évaluation nous permet de proposer des techniques de clustering dans un réseau de capteurs sans fil linéaire. Nous supposons d’abord un clustering basé sur une exploitation logique du voisinage des noeuds capteurs. Nous considérons dans ce cas, un modèle de propagation déterministe qui ne tient pas en compte la complexité du milieu. Ensuite, nous considérons une technique de clustering dans laquelle le modèle de propagation prend en compte les fluctuations qui rendent le milieu complexe. / In this thesis, we propose a MAC protocol that takes into account the specific characteristics of LSNs. This MAC protocol is based on tokens circulating that give the right to nodes to access to the transmission channel. We evaluate from this protocol the impact of interference and connectivity in the LSN. This evaluation allows us to propose clustering techniques in a LSN. We assume first a clustering based on a logical exploitation of the vicinity of the sensor nodes. In this case, we assume that a deterministic propagation model that does not take into account the complexity of the environment. Next, we consider a clustering technique wherein the propagation model takes into account the fluctuations that make complex the medium.
55

Studies of the Carbon and Energy Metabolism in the Moss Physcomitrella patens

Nilsson, Anders January 2009 (has links)
Since a proper balance between anabolic and catabolic reactions is essential for all eukaryotes, the basic mechanisms for regulation of the energy and carbon metabolism have been conserved throughout evolution. The moss Physcomitrella patens, which belongs to one of the basal clades among land plants, has many unique properties that make it an excellent plant model system. We have used a yeast two-hybrid system to identify novel possible regulators or targets of the moss Snf1-related kinases, previously shown to regulate energy homeostasis. The function of the identified interactors PpSki1 and PpSki2 was analyzed in order to better understand the biological role of plant Snf1-related kinases. The recently completed genome sequence of Physcomitrella was used in a comparative approach to study to what extent key enzyme and gene families involved in transport and metabolism of sugars and in regulation of the energy and carbon metabolism are conserved between mosses and vascular plants. It has long been known that transformed DNA can replicate episomally in Physcomitrella. We have now shown that such DNA can be rescued back into E. coli. Surprisingly, we found that the original plasmid can be recovered from moss transformants obtained with circular DNA. Plasmids rescued from transformants obtained with linearized DNA had been repaired either by homologous recombination or by cohesive end re-ligation. These findings suggest that methods using shuttle plasmids are feasible in Physcomitrella. Hexokinase, a key enzyme in the carbon metabolism, catalyzes the first step in hexose metabolism, but is also involved in sugar sensing and signaling. We have now made an initial characterization of the complete hexokinase family in Physcomitrella which is encoded by 11 genes. Two new types of plant hexokinases, types C and D, were found in addition to the previously described types A and B.
56

Structural and geologic controls on gigantic (>1 Gm³) landslides in carbonate sequences: case studies from the Zagros Mountains, Iran and Rocky Mountains, Canada

Roberts, Nicholas Jason January 2008 (has links)
Two gigantic landslides in carbonate sequences were studied through a combination of remotely sensed datasets and detailed field investigation. Field investigations supplemented the remote analysis at both sites. The work presents the first detailed documentation of the Seymareh (Saidmarreh) landslide, Zagros Mountains, Iran, which is shown to be the largest known rock avalanche in the world and the largest known landslide of any type on the Earth’s land surface. Volume of the Seymareh rock avalanche (38 Gm³) was previously underestimated by nearly 50 percent. The failure mode was complex planar sliding involving fold-related bedding-parallel shears and local break-through of bedding. The overall dip of the sliding surface was 11°. Lateral release and toe release were provided by tectonically-weakened joints and by break-out likely assisted by fluvial undercutting, respectively. Broad scar morphology and outcrop-scale features indicate the presence of nine discrete sliding surfaces distributed through the failed sequence and define nine stacked plates involved in the detachment. The Valley of the Rocks rock avalanche (1.3 Gm³), Rocky Mountains, Canada is described in detail for the first time and shown to be the largest known rock avalanche in North America as well as the largest known landslide of any type in Canada. The failure mode was simple planar sliding along a bedding-parallel, slightly concave-up surface possibly coinciding with a thrust fault (average dip 25°). Lateral release and toe release were provided by bedding-normal joints and by glacial undercutting, respectively. There is a surprisingly high degree of similarity between the two rock avalanches, despite differences in tectonic and climatic setting.. Similarities and differences between the two gigantic landslides suggest several factors important in volume determination of gigantic landslides in carbonate sequences: 1) extensive contiguous source slope; 2) high degree of structural continuity, especially across slope parallel to strike; 3) a comparatively low failure surface dip; 4) discontinuity-parallel slopes, and subsequent toe undercutting; and 5) hard-over-soft geomechanical contrasts. Comparison with magnitude-mobility relationships for landslides over five orders of magnitude shows that the Seymareh rock avalanche suggests an upper limit for landslide mobility (fahrböschung = ~4°) on the Earth’s continental surface.
57

Structural and geologic controls on gigantic (>1 Gm³) landslides in carbonate sequences: case studies from the Zagros Mountains, Iran and Rocky Mountains, Canada

Roberts, Nicholas Jason January 2008 (has links)
Two gigantic landslides in carbonate sequences were studied through a combination of remotely sensed datasets and detailed field investigation. Field investigations supplemented the remote analysis at both sites. The work presents the first detailed documentation of the Seymareh (Saidmarreh) landslide, Zagros Mountains, Iran, which is shown to be the largest known rock avalanche in the world and the largest known landslide of any type on the Earth’s land surface. Volume of the Seymareh rock avalanche (38 Gm³) was previously underestimated by nearly 50 percent. The failure mode was complex planar sliding involving fold-related bedding-parallel shears and local break-through of bedding. The overall dip of the sliding surface was 11°. Lateral release and toe release were provided by tectonically-weakened joints and by break-out likely assisted by fluvial undercutting, respectively. Broad scar morphology and outcrop-scale features indicate the presence of nine discrete sliding surfaces distributed through the failed sequence and define nine stacked plates involved in the detachment. The Valley of the Rocks rock avalanche (1.3 Gm³), Rocky Mountains, Canada is described in detail for the first time and shown to be the largest known rock avalanche in North America as well as the largest known landslide of any type in Canada. The failure mode was simple planar sliding along a bedding-parallel, slightly concave-up surface possibly coinciding with a thrust fault (average dip 25°). Lateral release and toe release were provided by bedding-normal joints and by glacial undercutting, respectively. There is a surprisingly high degree of similarity between the two rock avalanches, despite differences in tectonic and climatic setting.. Similarities and differences between the two gigantic landslides suggest several factors important in volume determination of gigantic landslides in carbonate sequences: 1) extensive contiguous source slope; 2) high degree of structural continuity, especially across slope parallel to strike; 3) a comparatively low failure surface dip; 4) discontinuity-parallel slopes, and subsequent toe undercutting; and 5) hard-over-soft geomechanical contrasts. Comparison with magnitude-mobility relationships for landslides over five orders of magnitude shows that the Seymareh rock avalanche suggests an upper limit for landslide mobility (fahrböschung = ~4°) on the Earth’s continental surface.
58

B-cyclin/CDK Regulation of Mitotic Spindle Assembly through Phosphorylation of Kinesin-5 Motors in the Budding Yeast, <italic>Saccharomyces cerevisiae</italic>

Chee, Mark Kuan Leng January 2012 (has links)
<p>Although it has been known for many years that B-cyclin/CDK complexes regulate the assembly of the mitotic spindle and entry into mitosis, the full complement of relevant CDK targets has not been identified. It has previously been shown in a variety of model systems that B-type cyclin/CDK complexes, kinesin-5 motors, and the SCF<super>Cdc4</super> ubiquitin ligase are required for the separation of spindle poles and assembly of a bipolar spindle. It has been suggested that in the budding yeast,<italic> Saccharomyces cerevisiae</italic>, B-type cyclin/CDK (Clb/Cdc28) complexes promote spindle pole separation by inhibiting the degradation of the kinesins-5 Kip1 and Cin8 by the anaphase-promoting complex (APC<super>Cdh1</super>). I have determined, however, that the Kip1 and Cin8 proteins are actually present at wild-type levels in yeast in the absence of Clb/Cdc28 kinase activity. Here, I show that Kip1 and Cin8 are in vitro targets of Clb2/Cdc28, and that the mutation of conserved CDK phosphorylation sites on Kip1 inhibits spindle pole separation without affecting the protein's <italic>in vivo</italic> localization or abundance. Mass spectrometry analysis confirms that two CDK sites in the tail domain of Kip1 are phosphorylated in vivo. In addition, I have determined that Sic1, a Clb/Cdc28-specific inhibitor, is the SCF<super>Cdc4</super> target that inhibits spindle pole separation in cells lacking functional Cdc4. Based on these findings, I propose that Clb/Cdc28 drives spindle pole separation by direct phosphorylation of kinesin-5 motors. </p><p>In addition to the positive regulation of kinesin-5 function in spindle assembly, I have also found evidence that suggests CDK phosphorylation of kinesin-5 motors at different sites negatively regulates kinesin-5 activity to prevent premature spindle pole separation. I have also begun to characterize a novel putative role for the kinesins-5 in mitochondrial genome inheritance in <italic>S. cerevisiae</italic> that may also be regulated by CDK phosphorylation. </p><p>In the course of my dissertation research, I encountered problems with several established molecular biology tools used by yeast researchers that I have tried to address. I have constructed a set of 42 plasmid shuttle vectors based on the widely used pRS series for use in <italic>S. cerevisiae</italic> that can be propagated in the bacterium Escherichia coli. This set of pRSII plasmids includes new shuttle vectors that can be used with histidine and adenine auxotrophic laboratory yeast strains carrying mutations in the genes <italic>HIS2</italic> and <italic>ADE1</italic>, respectively. My new pRSII plasmids also include updated versions of commonly used pRS plasmids from which common restriction sites that occur within their yeast-selectable biosynthetic marker genes have been removed in order to increase the availability of unique restriction sites within their polylinker regions. Hence, my pRSII plasmids are a complete set of integrating, centromere and 2&#61549; episomal plasmids with the biosynthetic marker genes <italic>ADE2</italic>, <italic>HIS3</italic>, <italic>TRP1</italic>, <italic>LEU2</italic>, <italic>URA3</italic>, <italic>HIS2</italic> and <italic>ADE1</italic> and a standardized selection of at least 16 unique restriction sites in their polylinkers. Additionally, I have expanded the range of drug selection options that can be used for PCR-mediated homologous replacement using pRS plasmid templates by replacing the G418-resistance kanMX4 cassette of pRS400 with MX4 cassettes encoding resistance to phleomycin, hygromycin B, nourseothricin and bialaphos. Finally, in the process of generating the new plasmids, I have determined several errors in existing publicly available sequences for several commonly used yeast plasmids. Using updated plasmid sequences, I constructed pRS plasmid backbones with a unique restriction site for inserting new markers in order to facilitate future expansion of the pRS/pRSII series.</p> / Dissertation
59

Análisis y ajuste de modelos digitales de elevaciones en la región central de la Argentina

Galván, Lucrecia January 2014 (has links)
El objetivo general del trabajo es evaluar el comportamiento del modelo de elevaciones SRTM 90m DEM (Modelo Digital de Elevaciones de la Misión Topográfica de Radar del Transbordador) sobre una zona extendida y de topografía muy variada de la República Argentina e incorporar información local al mismo. La técnica de interferometría de radar se ha analizado y utilizado para explicar el comportamiento del modelo en algunos puntos singulares de la zona de aplicación de esta tesis. La zona de trabajo incluyó parte de las provincias de Buenos Aires, La Pampa, Mendoza, Río Negro y Neuquén. Como información de referencia terrestre, se utilizaron puntos pertenecientes a la Red altimétrica del IGN y a la Red POSGAR07. En particular la Red GEOBA98 y su densificación, con puntos altimétricos GPS sobre todo el territorio de la provincia de Buenos Aires, representó la información de referencia que permitió: generar el DEM mejorado, mediante la integración de sus puntos, y la evaluación de su precisión externa. El DEM mejorado (HSRTM DEMMEJ) obtenido en este trabajo, para la zona de estudio, representa un avance con respecto al modelo original SRTM 90m DEM v4.1 CGIAR-CSI. El modelo gravitacional terrestre EGM96 asociado al SRTM 90 m fue analizado y utilizado como indicador del comportamiento de las alturas elipsoidales del geoide en la zona de estudio. Este análisis permitió expresar el nuevo DEM mejorado en coordenadas elipsoidales para facilitar su aplicación en relación a las determinaciones GNSS e independizarlo del modelo geopotencial utilizado. Los nuevos modelos geopotenciales, como el EGM2008, han significado una sensible mejora en la representación del geoide en gran parte de nuestro país. Por ello, finalmente se obtiene un modelo de elevaciones cuyas alturas se encuentran referidas al modelo gravitacional terrestre EGM2008 (HSRTM Nuevo). Las mejoras obtenidas son estimadas poniendo en consideración las características topográficas de las regiones estudiadas. Este nuevo modelo proporciona precisiones de una decena de centímetros
60

Avalia??o da aptid?o cardiorrespirat?ria pelo Incremental Shuttle Walking Test em crian?as e adolescentes assintom?ticos do sexo masculino

Gomes, Andreza Let?cia 10 November 2017 (has links)
O orientador do trabalho n?o mencionado na lista da folha de aprova??o. / Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2018-08-06T18:31:52Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) andreza_leticia_gomes.pdf: 1090108 bytes, checksum: 96eed10c887fbcff28a65cbd64874639 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2018-10-05T19:12:17Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) andreza_leticia_gomes.pdf: 1090108 bytes, checksum: 96eed10c887fbcff28a65cbd64874639 (MD5) / Made available in DSpace on 2018-10-05T19:12:17Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) andreza_leticia_gomes.pdf: 1090108 bytes, checksum: 96eed10c887fbcff28a65cbd64874639 (MD5) Previous issue date: 2018 / O Incremental Shuttle Walking Test (ISWT) vem sendo utilizado na avalia??o da aptid?o cardiorrespirat?ria (ACR) de crian?as e adolescentes com diferentes condi??es de sa?de. N?o se sabe se a resposta cardiorrespirat?ria apresentada por adolescentes saud?veis no ISWT ir? se assemelhar aquela induzida pelo teste de esfor?o cardiopulmonar (TECP). Os objetivos deste estudo foram: (1) Avaliar se o ISWT ? um teste m?ximo para adolescentes assintom?ticos do sexo masculino. (2) Propor uma equa??o matem?tica para predizer o pico do consumo de oxig?nio (VO2 pico) e, (3) testar a confiabilidade dessa equa??o para essa popula??o. M?todos: No primeiro est?gio do estudo, 26 participantes realizaram o ISWT e o TECP. No segundo est?gio 50 participantes realizaram o ISWT duas vezes. Em ambos os est?gios foram avaliados VO2 pico, a frequ?ncia card?aca m?xima (FC m?x.) e o pico da raz?o de troca respirat?ria (R pico). No terceiro est?gio foram comparados os valores do VO2 pico preditos pela equa??o criada e obtidos de forma direta no ISWT. Resultados: N?o houve diferen?a significativa no VO2 pico, R pico e FC m?x. obtidos no ISWT e TECP. Os valores encontrados para o VO2 pico (r = 0,44. p = 0,002) e R pico (r = -0,53, p< 0,01) obtidos no ISWT e TECP apresentaram correla??o moderada e significativa, al?m de concord?ncia na an?lise de Bland-Altman. A velocidade da marcha foi a vari?vel que explicou 48% (R2 = 0,48, p = 0,000) da varia??o no VO2 pico no ISWT. Foi criada a equa??o VO2 previsto = 5,490 + (17,093 x Velocidade da Marcha). Os resultados obtidos pela equa??o foram comparados com os valores obtidos pelo analisador de gases e nenhuma diferen?a significativa foi encontrada entre eles. Conclus?es: Em crian?as e adolescentes do sexo masculino o ISWT ? um teste de esfor?o m?ximo com repercuss?es cardiorrespirat?rias similares ao TECP. A equa??o preditiva proposta ? uma estimativa vi?vel para predi??o do VO2 pico para essa popula??o. / Disserta??o (Mestrado Profissional) ? Programa de P?s-Gradua??o em Reabilita??o e Desempenho Funcional, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2017. / The Incremental Shuttle Walking Test (ISWT) has been used to evaluate the Cardiorespiratory Fitness (CRF) of children and adolescents with different pathological conditions. It is unknown whether the cardiorespiratory response presented by asymptomatic adolescents in ISWT will be similar to that induced by CardiopulmonaryExerciseStress Test (CEPT). The aims of this study were: (1) To evaluate whether ISWT is a maximum test for asymptomatic male adolescents. (2) To propose a mathematical equation to predict peak oxygen consumption (VO2 peak) and (3) Totest the reliability of this equation on this population. Methods: In the first stage of the study, 26 participants performed the ISWT and the CEPT. In the second stage 33 participants performed the ISWT twice. In both stages, peak VO2, maximal heart rate (HR max) and peak respiratory rate (peak R) were evaluated. In the third stage, the peak VO2 values predicted by the equation created and obtained directly in the ISWT were compared. Results: There was no significant difference in the peak VO2 (p> 0.05), peak R (p> 0.05) and maximum HR obtained in ISWT and CEPT. The values found for the VO2 peak (r = 0.44, p = 0.002) and peak R (r = -0.53, p <0.01) obtained in the ISWT and CEPT presented a moderate correlation and anagreement in the analysis of Bland-Altman analysis. The gait speed was the variable that explained 48% (R2 = 0.48, p = 0.000) of the variation in the peak VO2. The VO2 peak equation = 5.490 + (17.093 x Gait Speed) was created. The results obtained by the equation were compared with the values obtained by the gas analyzer and no significant differences were found between them (p> 0.05). Conclusion: ISWT produced a cardiorespiratory response comparable to CEPT in asymptomatic male adolescents, and the developed equation presented viability to predict peak VO2 in adolescents.

Page generated in 0.022 seconds