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DESCRIPTION DE LA CIRCULATION OCEANIQUE ET DE SA VARIABILITE DANS L'OCEAN ATLANTIQUE TROPICALBourlès, B. 14 October 2010 (has links) (PDF)
C'est dans les années 1980 que l'importance de l'Atlantique Tropical sur le climat des régions avoisinantes a été clairement mise en évidence, notamment grâce à l'expérience FOCAL-SEQUAL. Celle-ci a également permis d'observer des tourbillons et des ondes océaniques influant sur la circulation et les transports de chaleur de petite et moyenne échelles spatio-temporelles. Avec le programme WOCE des années 1990 et les mesures effectuées de la surface au fond de l'océan, le rôle de l'Atlantique Tropical sur la circulation thermohaline de grande échelle a pu également être identifié. Dans ce mémoire, je vais décrire mes différentes contributions aux observations et aux analyses portant sur toutes les dimensions de ce bassin Atlantique Tropical, de la surface au fond, et de l'Ouest vers l'Est et le Golfe de Guinée. Ces travaux m'ont amené à initier et à coordonner des programmes de recherche et de formation universitaire, qui seront également évoqués. Je conclurai par des perspectives de recherche spécifiques à la région Est du bassin, et d'observations, tant en terme de campagnes de mesures que de réseaux.
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Underlying patterns that shape ecological restoration in the post-colonial landscape of the Ainu Moshir (land) of Hokkaido, JapanShiga, Shinsaku 31 August 2011 (has links)
My main objective is to reveal and illustrate the patterns and processes underlying the practice of ecological restoration in post-colonial landscapes. To focus my analysis, I asked what these patterns are, and how they inhibit or enable the Iwor (Ainu Traditional Living Space) Restoration Project (IRP). The IRP is a state-funded project aimed at improving the well-being of Ainu in Hokkaido, Japan. I used interviews, participant observation and text analyses to elucidate the dynamics at work in and around the project.
My findings suggest that colonial and technological practices inhibit good ecological restoration practices in IRP by disengaging people, or more subtly preventing them from engaging with it. Colonially, structural and discursive marginalization maintains economic deprivation through denying progressive conversations about community empowerment. This process also reinforces subjective power relationships of Wajin, the ethnic majority, dominance.
Technologically, I observed signs of Borgmann’s (1984) “device paradigm” that are both institutionally (e.g. government agencies) and materially (e.g. infrastructure and tools) driving the IRP toward technological restoration and away from focal restoration. This was particularly apparent in such instances where means and ends were inverted, or the government agencies were inaccessible to the Ainu participants.
These patterns in turn make IRP less appealing for Ainu and other local peoples. However, I also found that the room for creativity and attention to human-nature relationships in ecological restoration allow creation of the new space where Ainu can assert their values more strongly. This is the Kotan Iwor where the space embodies both Iwor and iwor, two representations of Wajin and Ainu views of the “Traditional Living Space” respectively.
My findings on Kotan Iwor (the traditional settlement restoration site) suggest that there is a significant potential in the ecological restoration practices because of the practice’s inherent capacity to bring people and the landscape together in a creative context. With careful attention to colonial, technological, and other dynamics, good ecological restoration practices have the potential to restore and improve the well-being of indigenous and non-indigenous community members alike. / Graduate
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A chemical-biology approach for screening novel inhibitors of focal adhesion signaling in relation to breast cancer /Cao, Yangxiezi. January 2008 (has links)
Focal adhesion kinase (FAK), a non-receptor kinase, is a key regulator of integrin and focal adhesion signaling required for cancer cell survival, cell migration, and cell invasion. Amplification/Overexpression of FAK occurs in a wide variety of human cancers, supporting a role in carcinogenesis. Moreover, preclinical studies using cancer models where FAK is genetically inhibited indicate that this kinase is a potential therapeutic target to interfere with cancer progression. However, very little progress has been made in the identification of chemical inhibitors for potential therapeutic applications, in contrast to other kinases. Herein, I report optimization of the high-throughput in vitro Glo kinase assay for screening inhibitors of FAK kinase activity. Screening a large library of small molecule chemicals using these assays identified at least twenty FAK inhibitors, including a new FAK inhibitor developed by Pfizer and undergoing human clinical trials, and the non-specific kinase inhibitor staurosporine. Molecular studies of selective FAK inhibitors are undergoing in my host laboratory. In addition to this in vitro assay, I established similar assays to examine FAK kinase and adapter function in intact cells. The latter consists of ErbB-transformed cells deficient in FAK, and their matched cells where wild-type or kinase-dead FAK was restored. Biological characterization of these models revealed that both FAK kinase and adaptor activities cooperate for the regulation of cell migration, cell invasion, and tumor formation.
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Insb And Inassb Infrared Photodiodes On Alternative Substrates And Inp/ingaas Quantum Well Infrared Photodetectors: Pixel And Focal Plane Array PerformanceOzer, Selcuk 01 June 2005 (has links) (PDF)
InAsxSb1-x (Indium Arsenide Antimonide) is an important low bandgap
semiconductor whose high quality growth on GaAs or Si substrates is
indispensible for low cost, large format infrared focal plane arrays (FPAs).
Quantum well infrared photodetector (QWIP) technology, relying on mature
semiconductors, is also promising for the above purpose. While AlGaAs/GaAs
has been the standard material system for QWIPs, the search for alternative
materials is needed for better performance. This thesis reports a detailed
investigation of molecular beam epitaxy grown mid-wavelength infrared
InAsxSb1-x photodiodes on alternative substrates, and long wavelength infrared
InP/InGaAs QWIPs.
In the first part of the study, InSb and InAs0.8Sb0.2 photodiodes grown on Si and
GaAs substrates are investigated to reveal the performance degrading
mechanisms due to large lattice mismatch. InAs0.8Sb0.2/GaAs photodiodes yield
peak detectivities of 1.4× / 1010 and 7.5× / 108 cmHz½ / /W at 77 K and 240 K,
respectively, showing that the alloy is promising for both cooled and near room
temperature detectors. Under moderate reverse bias, 80 K RoA product limiting
mechanism is trap assisted tunneling, which introduces considerable 1/f noise.
InSb/Si photodiodes display peak 77 K detectivity as high as ~1× / 1010
cmHz 1/2/W and reasonably high peak quantum efficiency in spite of large lattice
mismatch. RoA product of detectors at 80 K is limited by Ohmic leakage with
small activation energy (25 meV). Bias and temperature dependence of 1/f noise
is in reasonable agreement with Kleinpenning&rsquo / s mobility fluctuation model,
confirming the validity of this approach.
The second part of the study concentrates on InP/In0.53Ga0.47As QWIPs, and
640× / 512 FPA, which to our knowledge, is the largest format InP/InGaAs QWIP
FPA reported. InP/InGaAs QWIPs yield quantum efficiency-gain product as
high as 0.46 under moderate bias. At 70 K, detector performance is background
limited with f/2 aperture up to ~3 V bias where peak responsivity (2.9 A/W) is
thirty times higher than that of the Al0.275Ga0.725As/GaAs QWIP with similar
spectral response. Impact ionization in InP/InGaAs QWIPs does not start until
the average electric-field reaches 25 kV/cm, maintaining high detectivity under
moderate bias.
The 640× / 512 InP/InGaAs QWIP FPA yields noise equivalent temperature
difference of ~40 mK at an FPA temperature as high as 77 K and reasonably low
NETD even with short integration times (t). 70 K NETD values of the FPA with
f/1.5 optics are 36 and 64 mK under &ndash / 0.5 V (t=11 ms) and &ndash / 2 V (t=650 Rs) bias,
respectively. The results clearly show the potential of InP/InGaAs QWIPs for
thermal imaging applications requiring short integration times.
Keywords: Cooled infrared detectors, InAsSb, QWIP, focal plane array.
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Long Wavelength Mercury Cadmium Telluride Photodiodes And Focal Plane ArraysAsici, Burak 01 September 2005 (has links) (PDF)
This thesis reports the fabrication and characterization of long wavelength infrared mercury cadmium telluride (Hg1-xCdxTe) photodiodes and 128x128 focal plane arrays grown on lattice matched cadmium zinc telluride (Cd1-yZnyTe) substrates by metal organic vapor phase epitaxy (MOVPE). The dark current modeling of 33x33 mm2 Hg1-xCdxTe photodiodes has shown the dark current is dominated by trap assisted tunneling under small reverse bias voltages typically used to bias these detectors. The dominant dark current mechanisms under high reverse bias and low forward bias are band&ndash / to&ndash / band tunneling and generation&ndash / recombination, respectively. The photodiodes have yielded a peak 77 K detectivity of 3.2x1010 cm& / #8730 / Hz/W with a cut-off wavelength (50%) of 10.92 mm. It has also been found that the 1/f noise current of the detectors at 1 Hz is related to the trap-assisted tunneling current through the empirical relation in=& / #945 / TAT(ITAT)& / #946 / with & / #945 / TAT=7.0 x 10-5 and & / #946 / =0.65.
In the course of the focal plane array (FPA) fabrication process development work, ohmic contact formation on p-type Hg1-xCdxTe and mesa wet etch were studied in detail. Contacts with chromium, gold, platinum and copper on p-type Hg1-xCdxTe resulted in bad ohmic contacts, which did not seem to improve with annealing. On the other hand a HgTe cap layer on p-type Hg1-xCdxTe resulted in good ohmic contact with acceptably low resistance. Among the etchants studied for mesa etching of the diode structures, Br2/HBr solution yielded the best performance.
After developing all of the steps of FPA processing, 128x128 Hg1-xCdxTe FPAs were successfully fabricated and tested in a thermal imager. While thermal imaging was performed with the FPAs, high nonuniformity of the material and low R0A product of the pixels did not allow high sensitivity imaging.
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Experimentally induced cortical plasticity: neurophysiological and functional correlates in health and disease.Schabrun, Siobhan M. January 2010 (has links)
Neuroplasticity provides the basis for many of our most fundamental processes including learning, memory and the recovery of function following injury. This thesis is concerned with the neurophysiological and functional correlates of sensorimotor neuroplasticity in the healthy and focal dystonic populations. My initial experiments were conducted to determine the functional correlates of neuroplasticity induced in the primary motor (M1) and primary sensory (S1) cortices during a grip lift task. In healthy subjects these experiments further quantified the role of M1 in the anticipatory control of grip force scaling and demonstrated a role for S1 in triggering subsequent phases of the motor plan. My second series of experiments served to extend these findings by examining the functional correlates of neuroplasticity induced in the supplementary motor area (SMA). This study provided evidence for the role of left SMA in the control of grip force scaling and a role for left and right SMA in the synchronization of grip force and load force during the grip-lift synergy. Afferent input is known to be a powerful driver of cortical reorganisation. In particular, the timing and pattern of afferent input is thought to be crucial to the induction of plastic change. In healthy subjects, I examined the neurophysiological effects of applying “associative” (synchronous) and “non-associative” (asynchronous) patterns of afferent input to the motor points or digits of the hand. I observed an increase in the volume and area of the cortical representation of stimulated muscles when associative stimulation was applied over the motor points of two hand muscles. This pattern of stimulation also caused the centres of gravity of the stimulated muscles to move closer together, mimicking the maladaptive changes seen in focal hand dystonia. Non-associative stimulation and stimulation applied to the digits did not produce such an effect. Task-specific focal dystonia is characterised by excessive representational plasticity resulting in cortical representations which are significantly larger, and demonstrate greater overlap, than those seen in healthy individuals. These changes are thought to be driven, in part, by repetitive movement patterns which promote associative patterns of afferent input over an extended time period. On the basis of this knowledge, I applied non-associative stimulation to the hand muscles of dystonic subjects. Following this intervention, I noted a contraction of representational maps and a separation in the centres of gravity of the stimulated muscles. These neurophysiological changes were accompanied by improvements on a cyclic drawing task. This thesis demonstrates the functional correlates of neuroplasticity in M1, S1 and SMA during object manipulation using a precision grasp. These findings further extend our knowledge on the mechanisms underlying effective grasp control and assist us in the development of future rehabilitation protocols for neurological conditions involving grasp dysfunction. In addition, this thesis is the first to demonstrate an improvement in both neurophysiological and functional measures in focal dystonia following a period of non-associative afferent stimulation. These results open up exciting new avenues for the development of effective treatment protocols in those with focal hand dystonia. / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2010
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Experimentally induced cortical plasticity: neurophysiological and functional correlates in health and disease.Schabrun, Siobhan M. January 2010 (has links)
Neuroplasticity provides the basis for many of our most fundamental processes including learning, memory and the recovery of function following injury. This thesis is concerned with the neurophysiological and functional correlates of sensorimotor neuroplasticity in the healthy and focal dystonic populations. My initial experiments were conducted to determine the functional correlates of neuroplasticity induced in the primary motor (M1) and primary sensory (S1) cortices during a grip lift task. In healthy subjects these experiments further quantified the role of M1 in the anticipatory control of grip force scaling and demonstrated a role for S1 in triggering subsequent phases of the motor plan. My second series of experiments served to extend these findings by examining the functional correlates of neuroplasticity induced in the supplementary motor area (SMA). This study provided evidence for the role of left SMA in the control of grip force scaling and a role for left and right SMA in the synchronization of grip force and load force during the grip-lift synergy. Afferent input is known to be a powerful driver of cortical reorganisation. In particular, the timing and pattern of afferent input is thought to be crucial to the induction of plastic change. In healthy subjects, I examined the neurophysiological effects of applying “associative” (synchronous) and “non-associative” (asynchronous) patterns of afferent input to the motor points or digits of the hand. I observed an increase in the volume and area of the cortical representation of stimulated muscles when associative stimulation was applied over the motor points of two hand muscles. This pattern of stimulation also caused the centres of gravity of the stimulated muscles to move closer together, mimicking the maladaptive changes seen in focal hand dystonia. Non-associative stimulation and stimulation applied to the digits did not produce such an effect. Task-specific focal dystonia is characterised by excessive representational plasticity resulting in cortical representations which are significantly larger, and demonstrate greater overlap, than those seen in healthy individuals. These changes are thought to be driven, in part, by repetitive movement patterns which promote associative patterns of afferent input over an extended time period. On the basis of this knowledge, I applied non-associative stimulation to the hand muscles of dystonic subjects. Following this intervention, I noted a contraction of representational maps and a separation in the centres of gravity of the stimulated muscles. These neurophysiological changes were accompanied by improvements on a cyclic drawing task. This thesis demonstrates the functional correlates of neuroplasticity in M1, S1 and SMA during object manipulation using a precision grasp. These findings further extend our knowledge on the mechanisms underlying effective grasp control and assist us in the development of future rehabilitation protocols for neurological conditions involving grasp dysfunction. In addition, this thesis is the first to demonstrate an improvement in both neurophysiological and functional measures in focal dystonia following a period of non-associative afferent stimulation. These results open up exciting new avenues for the development of effective treatment protocols in those with focal hand dystonia. / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2010
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Experimentally induced cortical plasticity: neurophysiological and functional correlates in health and disease.Schabrun, Siobhan M. January 2010 (has links)
Neuroplasticity provides the basis for many of our most fundamental processes including learning, memory and the recovery of function following injury. This thesis is concerned with the neurophysiological and functional correlates of sensorimotor neuroplasticity in the healthy and focal dystonic populations. My initial experiments were conducted to determine the functional correlates of neuroplasticity induced in the primary motor (M1) and primary sensory (S1) cortices during a grip lift task. In healthy subjects these experiments further quantified the role of M1 in the anticipatory control of grip force scaling and demonstrated a role for S1 in triggering subsequent phases of the motor plan. My second series of experiments served to extend these findings by examining the functional correlates of neuroplasticity induced in the supplementary motor area (SMA). This study provided evidence for the role of left SMA in the control of grip force scaling and a role for left and right SMA in the synchronization of grip force and load force during the grip-lift synergy. Afferent input is known to be a powerful driver of cortical reorganisation. In particular, the timing and pattern of afferent input is thought to be crucial to the induction of plastic change. In healthy subjects, I examined the neurophysiological effects of applying “associative” (synchronous) and “non-associative” (asynchronous) patterns of afferent input to the motor points or digits of the hand. I observed an increase in the volume and area of the cortical representation of stimulated muscles when associative stimulation was applied over the motor points of two hand muscles. This pattern of stimulation also caused the centres of gravity of the stimulated muscles to move closer together, mimicking the maladaptive changes seen in focal hand dystonia. Non-associative stimulation and stimulation applied to the digits did not produce such an effect. Task-specific focal dystonia is characterised by excessive representational plasticity resulting in cortical representations which are significantly larger, and demonstrate greater overlap, than those seen in healthy individuals. These changes are thought to be driven, in part, by repetitive movement patterns which promote associative patterns of afferent input over an extended time period. On the basis of this knowledge, I applied non-associative stimulation to the hand muscles of dystonic subjects. Following this intervention, I noted a contraction of representational maps and a separation in the centres of gravity of the stimulated muscles. These neurophysiological changes were accompanied by improvements on a cyclic drawing task. This thesis demonstrates the functional correlates of neuroplasticity in M1, S1 and SMA during object manipulation using a precision grasp. These findings further extend our knowledge on the mechanisms underlying effective grasp control and assist us in the development of future rehabilitation protocols for neurological conditions involving grasp dysfunction. In addition, this thesis is the first to demonstrate an improvement in both neurophysiological and functional measures in focal dystonia following a period of non-associative afferent stimulation. These results open up exciting new avenues for the development of effective treatment protocols in those with focal hand dystonia. / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2010
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Regulation and substrate specificity of the Git and AZAP ARTGAP families /Cuthbert, Ellen Jebb. January 2008 (has links)
Thesis (Ph. D.)--University of Virginia, 2008. / Includes bibliographical references. Also available via the Internet as viewed 10 July 2008.
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Role of focal adhesion kinase in mammary gland tumorigenesis /Pylayeva, Yuliya. January 2008 (has links)
Thesis (Ph. D.)--Cornell University, May, 2008. / Vita. Includes bibliographical references (leaves 115-128).
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