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1
Eberle, Dominique Gilbert Basil. „Neue Translokation t(11;11)(q23;q13) bei akuter myeloischer Leukämie : Suche nach einem unbekannten Partner-Gen /“. [S.l.] : [s.n.], 2009. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000281145.
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2
Outram, Philip James. „QSO absorption systems“. Thesis, University of Cambridge, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624575.
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3
Webb, J. K. „QSO absorption lines“. Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234000.
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The absorption lines found in the spectra of distant quasars provide a unique method of probing the physical conditions in the universe at early epochs. This thesis describes a study of the Lyman alpha forest absorption systems seen in the spectra of high redshift QSOs. The Anglo-Australian Telescope has been used to obtain high resolution spectra of several bright QSOs. Considerable effort has gone into developing statistical techniques for profile fitting to the data to objectively and reliably extract the parameters associated with each absorbing cloud. The distribution functions for these are given and discussed. Particular attention has been paid to the clustering properties of the Lyman alpha clouds and it is found that they are weakly (but significantly) clustered on small velocity scales. Possible interpretations of this result are discussed. One especially interesting aspect of QSO absorption systems concerns the potential for measuring, or obtaining limits on, the deuterium to hydrogen abundance at high redshifts. A knowledge of this quantity is important for constraining cosmological models and can also help us to understand the chemical evolution of light elements in galaxies. A series of numerical simulations has been carried out to explore the potential for such measurements and an absorption system has been analysed to obtain an upper limit to D/H at z = 3.
4
Smith, Robert James. „QSO clustering and environments“. Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624809.
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5
Jahnke, Knud. „Stellar populations of QSO host galaxies“. [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=965227995.
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6
Zare, Haidi. „On spherical classes in H*QSⁿ“. Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.499135.
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We consider the problem of determining spherical classes In H*QS¹. We take a geometrical approach and show how existence of specific classes as a spherical class In H*QS¹ will determine the type of homology operations that can detect the related homotopy class. Most of our results here are quite general, and can be applied to H*QX, with X an arbitrary path connected space. We see this as an approach to attack the conjecture of Ed Curtis about spherical classes in H*Q₀S⁰.
7
Ellison, S. L. „The chemical evolution of QSO absorbers“. Thesis, University of Cambridge, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.598835.
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Using quasar absorption lines as a probe of the high redshift universe is a powerful tool in the field of chemical evolution. In this thesis, I consider the elemental abundances in absorbers that correspond to a variety of environments, ranging from high redshift galaxies to the low density intergalactic medium. I firstly address the question of abundances in intermediate redshift (zabs < 1.5) damped Lyα systems (DLAs), objects believed to correspond to the progenitors of present day massive galaxies. I present Hubble Space Telescope (HST) spectra of six intermediate redshift DLAs which have been supplemented with high resolution spectroscopy obtained with the high resolution echelle spectrograph (HIRES) on the Keck telescope. The chemical abundances of a range of elements are investigated and compared with local Galactic values in order to gain an insight into the metallicities, dust-to-gas ratios and star formation histories of these systems. The results from this work have inspired a new survey for DLAs based on a radio-selected sample of QSOs. The motivation for this endeavour has been to determine the extent to which our current view of distant galaxies is obscured by dust. I present intermediate resolution spectra obtained at the Anglo-Australian Telescope (AAT) from which DLAs may be identified. The number statistics of the newly discovered DLAs are analysed in order to determine whether obscuration by dust of background QSOs causes a significant observational bias. Finally, I consider the metallicity of the IGM by studying C IV systems associated with the Lyα forest at z ~ 3. The extent to which the IGM has been polluted with metals will provide important clues to the enrichment mechanism. I firstly investigate the column density distribution function of strong C IV absorbers associated with high column density Lyα clouds. This work is then extended to consider the C IV/H 1 ratio in low column density absorbers which are associated with physically less dense material. The spectra of two high redshift QSOs are analysed using two different techniques, both of which are critically assessed using synthetic spectra.
8
Larrea, Erik Aris Stengler. „Cosmological evolution of QSO absorption systems“. Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339588.
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9
López-Corredoira, M., F. Melia, E. Lusso und G. Risaliti. „Cosmological test with the QSO Hubble diagram“. World Scientific Publishing, 2016. http://hdl.handle.net/10150/615119.
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A Hubble diagram (HD) has recently been constructed in the redshift range
$0\lesssim z\lesssim 6.5$ using a non-linear relation between the ultraviolet and
X-ray luminosities of QSOs. The Type Ia SN HD has already provided a high-precision
test of cosmological models, but the fact that the QSO distribution extends well
beyond the supernova range ($z\lesssim 1.8$), in principle provides us with an
important complementary diagnostic whose significantly greater leverage in $z$
can impose tighter constraints on the distance versus redshift relationship. In
this paper, we therefore perform an independent test of nine different cosmological
models, among which six are expanding, while three are static. Many of these are
disfavoured by other kinds of observations (including the aforementioned Type Ia
SNe). We wish to examine whether the QSO HD confirms or rejects these earlier
conclusions. We find that four of these models (Einstein-de Sitter, the Milne
universe, the Static Universe with simple tired light and the Static universe
with plasma tired light) are excluded at the $>99\%$ C.L. The Quasi-Steady State
Model is excluded at $>95$\% C.L. The remaining four models ($\Lambda$CDM/$w$CDM,
the $R_{\rm h}=ct$ Universe, the Friedmann open universe and a Static universe
with a linear Hubble law) all pass the test. However, only $\Lambda$CDM/$w$CDM
and $R_{\rm h}=ct$ also pass the Alcock-Paczy\'nski (AP) test. The optimized
parameters in $\Lambda$CDM/$w$CDM are $\Omega _m=0.20^_$ and
$w_{de}=-1.2^_$ (the dark-energy equation-of-state). Combined
with the AP test, these values become $\Omega _m=0.38^_$ and
$w_{de}=-0.28^_$. But whereas this optimization of parameters
in $\Lambda$CDM/$w$CDM creates some tension with their concordance values,
the $R_=ct$ Universe has the advantage of fitting the QSO and AP data
without any free parameters.
10
Dinshaw, Nadine 1964. „The spatial extent and correlations of QSO absorbers“. Diss., The University of Arizona, 1996. http://hdl.handle.net/10150/290639.
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The lines of sight to QSOs are powerful probes of large-scale structure from redshifts corresponding to the most distant QSOs to the local universe. In this thesis, spectroscopy of QSO pairs and groups are used to study superclustering at high redshift and to estimate the tranverse dimensions of the Lyα absorbers. We present high resolution (∼30km s⁻¹) echelle spectra obtained with the CTIO 4-m telescope of the wide QSO pair Tol 1037—2704 (z(em) = 2.193) and Tol 1038—2712 (z(em) = 2.331), as well as two neighboring quasars. The quasars exhibit a large number of apparently correlated C IV absorption systems over a narrow redshift range 1.48 ≤ 2 ≤ 2.15 which is thought to be produced by an intervening supercluster. The velocity correlation function of C IV absorbers distributed among the four lines of sight show significant clustering signal on comoving scales out to ∼30 h⁻¹ Mpc at redshift z ∼ 2 (h ≡ H₀/100 km s⁻¹ Mpc⁻¹; q₀ = 0.5). The spatial correlation function shows a marginally significant peak on scales of < 18h⁻¹ Mpc. The clustering amplitude on these scales is larger than that predicted by current theories of the formation of large scale structure. We present spectroscopy of three close pairs of quasars with angular separations 10" to 2' in order to measure the sizes of the Lyα forest absorbers from scales of a few tens of kpc out to hundreds of kpc. Ground-based estimates of the pair Q1343+2640.A (z(em) = 2.029) and B (z(em) = 2.031) imply a characteristic radius of the Lyα absorbers of ∼100 h⁻¹ kpc at z ≃ 2. Ultraviolet FOS spectra of the pair Q0107—025A (z(em) = 0.956) and B (z(em) = 0.952) in the redshift range 0.5 < 2 < 0.9 show a number of Lyα absorption features common to both spectra as well as several features which are not in common, and imply characteristic radii of 400 h⁻¹ kpc to bigger than 1 h⁻¹ Mpc. Furthermore, the rms velocity difference between the common systems between the two lines of sight is only about 100 km s⁻¹ These measurements lead to a picture of absorbing clouds that are larger in extent than previously thought and surprisingly quiescent. Using a new statistical technique, we tested the relative likelihood of three geometric models, namely, spherical absorbers, with and without a distribution in size, as well as filamentary and disk-like absorbers. Spherical absorbers with uniform radius cannot represent the observations and are ruled out. Randomly-inclined disks and filaments match the data comparably, with disks being slightly favored over filaments. Our results are in remarkable agreement with hydrodynamical simulations in which the Lyα absorption is found to arise in diverse structures with coherence lengths as great as 1 Mpc. Finally, we present FOS observations of a second pair of quasars, LB 9605 (z(em) = 1.834) and LB 9612 (z(em) = 1.898), over the redshift range 1.1 < z < 1.7 from which we placed an 95% confidence upper limit on the radii of the Lyα absorbers of 280 h⁻¹ kpc. The estimates span the redshift range 0.5 < z < 2, corresponding to roughly a third of the age of the universe, and provide tantalizing evidence for evolutionary growth in the size of the Lyα absorbers
11
Keeney, Brian A. „Do starburst winds escape? Insights from QSO absorption lines“. Diss., Connect to online resource, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3239454.
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12
Lipman, Keith. „Chemical abundances of primeval galaxies from QSO absorption lines“. Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363292.
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13
Fakhouri, Onsi Joe 1983. „Constraining the QSO luminosity function using gravitational lensing statistics“. Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/32733.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics; and, (S.B.)--Massachusetts Institute of Technology, Dept. of Mathematics, 2004.Includes bibliographical references (leaves 85-87).
In this thesis we use gravitational lensing statistics to constrain the QSO luminosity function at a variety of redshifts. We present a theoretical discussion of gravitational lensing statistics and illustrate how high resolution QSO imagery can be used to constrain the QSO luminosity function. We then discuss the selection and observation of the 1073 QSO exposures in our sample. The sample covers a redshift range of 0.7
S.B.
14
Gharabaghi, Sara. „Quantitative Susceptibility Mapping (QSM) Reconstruction from MRI Phase Data“. Wright State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=wright1610018553822445.
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15
Zuo, Lin Phinney E. Sterl. „QSO absorption lines and the ionizing field at high redshifts /“. Diss., Pasadena, Calif. : California Institute of Technology, 1992. http://resolver.caltech.edu/CaltechETD:etd-09232008-081252.
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16
Locke, Devin Paul. „SEGMENTAL DUPLICATIONS PROMOTE GENOMIC INSTABILITY IN HUMAN CHROMOSOME 15q11-q13“. Case Western Reserve University School of Graduate Studies / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=case1088114861.
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17
Cruz, da Angela José Antonio. „Clustering and redshift-space distortions in QSO and galaxy surveys“. Thesis, Durham University, 2006. http://etheses.dur.ac.uk/2342/.
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In this thesis, we exploit the potential of existing QSO and galaxy surveys for investigating the nature of the large scale structure in the Universe. A detailed analysis of clustering and redshift- space distortions allows us to constrain cosmological parameters. We model the anisotropies due to dynamical and geometrical effects in the measured clustering pattern of distant QSOs from the 2dF QSO Survey (2QZ) and also Lyman break galaxies. The 2QZ is then combined with the QSO sample from the 2dF SDSS LRG and QSO Survey (2SLAQ) to study the luminosity dependence of QSO clustering. Using AT-body simulations, we estimate the statistical gains in the determination of cosmological parameters from future LRG surveys. We measure the clustering of distant QSOs from the 2QZ survey by performing a correlation analysis of redshift-space (z-space) distortions. To interpret the z-space correlation function measured in orthogonal directions, ع(σ,π)， we require an accurate model for the QSO real-space correlation function, ع (r). Motivated by the form for ع (r) seen in the 2dF Galaxy Redshift Survey (2dFGRS) and in standard ACDM predictions, we use a double power-law model for ع (r). which gives a good fit to the z-space and projected correlation functions. By fitting functional forms of ع(σ,π) which include both dynamical and geometrical modelling, we find, as expected, that β (which parameterises the infall into overdense regions) and the density of the Universe (Ω(^0_M)) are degenerate. However, this degeneracy can be lifted by using linear theory predictions under different cosmological scenarios. Using the 2QZ survey, we obtain: βQAO (z=1.4) = 0.50 (^0.13_0.15), Ω(^0_M) = 0.35 (^+0.19_-0.13). The modelling of geometrical and dynamical anisotropies in the measured ع(σ,π) pattern is then applied to a sample of distant Lymari-break galaxies. The presence of feedback mechanisms in these z〜 3 star-forming galaxies heightens the importance of understanding the effects of z-space distortions. Despite the limited size of the fields, which hampers the determination of ع(r) at large scales, we find that a double-power law ع(s) parameterisation is consistent with the correlation function measurements. This double power law model is then used as an input for the ع(σ,π) fitting and subsequent constraining of cosmological parameters. This investigation reveals that: ßLBG (z= 3) = 0.25± (^+0.05_-0.05) and Ω(^0_M) = 0.55(^+0.45_-0.16). The combination of the 2QZ with the fainter 2SLAQ QSO sample reveals that QSO clustering does not depend strongly on luminosity. This result is consistent with models which predict that haloes of similar mass can harbour QSOs of different luminosities. By assuming ellipsoidal models for the collapse of density perturbations, we test this hypothesis and estimate the mass of the dark matter haloes which the QSOs inhabit. We find that halo mass does not seem to evolve strongly with redshift nor depend on QSO luminosity. Having determined the black hole mass associated with the QSOs, we investigate how it correlates with luminosity and redshift and ascertain the relation between Eddington efficiency and black hole mass. Our results suggest that: (i) black hole mass does not depend strongly on accretion efficiency and (іі) black holes associated with QSOs of different luminosities have similar masses. Finally, the Hubble Volume simulation is used to construct a mock sample of a future ΑΑΩ Luminous Red Galaxy (LRG) survey. The ultimate aims of this survey are to identify the baryon acoustic features in the LRG clustering signal and to determine the equation of state of dark energy. We apply the z-space distortion analysis developed previously in the thesis to infer the statistical gain in terms of determinations of ß(_LRG) (z~ 0.7) and Ω(+0_m) .This thesis exploits the wealth of information contained in cosmological surveys, and demonstrates how the use of tools such as clustering statistics or z-space distortion analyses permit the extraction of such information.
18
Forsyth, Nicholas R. „Functional demonstration of a mortality phenotype associated with 4cen-q23“. Thesis, University of Glasgow, 2000. http://theses.gla.ac.uk/8487/.
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Normal human keratinocytes possess a finite replicative lifespan whereas most advanced squamous cells carcinomas are immortal. The mechanisms, whose abrogation's can be considered necessary to achieve immortality, include those involving the negative cell cycle regulators p53, p16INK4A, and the telomere repair reverse-transcriptase enzyme, telomerase. Other specific chromosomes have also been demonstrated to carry functions whose loss is necessary for the development of immortality, through immortal phenotype reversion upon reintroduction into an immortal cell line. We demonstrate here the phenotypic reversion of immortal HNSCC-derived keratinocyte cell lines to a mortal growth-arrest upon reintroduction of a resistance marker tagged wild-type human chromosome 4. We further demonstrate that this phenotypic reversion occurs only in cell lines, which display LOH on 4q (BICR6 and BICR31), and not in those with intact endogenous chromosome 4 copies (BICR3 and BICR19), and that it is chromosome 4-specific, chromosomes 6, 11, and 15 having no effect on proliferative lifespan following introduction into BICR6 by MMCT. Through XMMCT-based truncated chromosomal fragment generation the functional complementation was localised to 4cen-q23, whilst fine mapping in segregants arising from the MMCT experiments identified an approximate 1.5Mb locus containing a minimal number of candidate genes. Through biological assay we have further determined the growth-arrest to have characteristics of crisis. This was determined through low BrdU incorporation balanced with high levels of apoptosis to statistically significant levels (less than 0.05). We found no evidence for involvement of telomeric attrition in the observed phenotype, through insufficient phenotypic lag (3-10 MPD) and growth-arrest in the presence of ectopic hTERT expression, suggesting the operation of an alternative mechanism. This suggests the presence of gene(s) at 4cen-q23 whose loss is advantageous to the development of immortality in advanced tumours including HNSCC.
19
Newman, Janson. „QS Ranking Methodologies“. Universidad Peruana de Ciencias Aplicadas (UPC), 2018. http://hdl.handle.net/10757/623345.
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Conferencia realizado el 19 de Abril de 2018 en las instslaciones de la Universidad Peruana de Ciencias Aplicadas (UPC), campus San Isidro. Lima Perú. Evento auspiciado por Universidad y FIPES.Conferencia acerca de la importancia de los rankings universitarios: caso QS World University Rankings.
20
Londish, Diana. „Properties of BL Lac objects from the 2dF QSO Redshift Survey“. University of Sydney. Physics, 2003. http://hdl.handle.net/2123/600.
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This thesis is an analysis of the X-ray, optical, infrared and radio properties of a sample of candidate BL Lac objects, identified from two catalogues of colour-selected point sources, the 2QZ and 6QZ. The importance of the sample lies in the fact that it is the first BL Lac sample in which initial selection has been made from optical spectra, independent of the objects' flux levels at X-ray and radio frequencies. These optically selected candidate BL Lac objects thus provide an unbiased sample (in terms of radio flux density) with which to study the proportion of radio- dominant and X-ray-dominant BL Lac objects in the global population. The observed number counts and redshift distribution of the 2BL are consistent with theoretical predictions based on the QSO evolutionary model. Given the small number statistics we are not, however, able to show that this distribution is significantly different to that of the 2QZ/6QZ white dwarfs. A median redshift of z=1.25 was computed for these candidate BL Lacs, a value supported by redshift information obtained for ~25% of the sample. This median redshift is much higher than redshifts found for X-ray selected BL Lac objects and suggests that in the past high redshift, low luminosity, radio-weak BL Lacs may have been missed in radio- and X-ray-selected samples. From results of the above studies it appears that this sample of optically selected candidate BL Lac objects is different to that of hitherto known radio-loud BL Lacs. We explore mechanisms that might produce such radio-weak/radio-quiet continuum objects, and also demonstrate that such radio-quiet BL Lac objects could exist at low redshift. Failure to include these radio-quiet BL Lacs in X-ray selected samples could explain the negative evolution found for this class of object.
21
Stafford, Amanda Newland. „Physical mapping within human chromosome 11q12-q13 including the atopy locus“. Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239248.
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22
Murugesan, Saravanan. „Quantitative sensory testing (QST) to establish normative vibratory and thermal thresholds“. Thesis, University of Strathclyde, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.502346.
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Quantitative Sensory Testing (QST) is emerging as a potential adjunct to the neurological examination in the evaluation of sensory dysfunction after Spinal Cord injury (SCI). In both clinical and research areas, the QST technique is used as an aid in early diagnosis, follow-up, and evaluations of therapy in SCI patients. QST's are psychophysical in nature, requiring cooperation from the patient. A normative database from healthy controls helps to establish neurological disorders or changes in sensory dysfunction during the SCI treatment. A deviation from the normal range can indicate the existence of neurological disorders in Spinal cord. The main objective of this study was to establish a normative database to evaluate the sensory dysfunction after SCI and to evaluate the reliability of the QST methodology.
23
Burles, Scott. „Measurements of the deuterium to hydrogen ratio in QSO absorption systems /“. Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC IP addresses, 1997. http://wwwlib.umi.com/cr/ucsd/fullcit?p9808982.
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24
Ita, Meagan Eleanor. „Comparison of Q3s Anthropomorphic Test Device Biomechanical Responses to Pediatric Volunteers“. The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1397486884.
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25
Fisher, Michael Lynn. „Theoretical studies of QSO absorption lines and the inter- galactic medium /“. The Ohio State University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487682558445736.
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26
Yi, Weimin, Richard Green, Jin-Ming Bai, Tinggui Wang, Catherine J. Grier, Jonathan R. Trump, William N. Brandt et al. „The Physical Constraints on a New LoBAL QSO at z = 4.82“. IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/623841.
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Very few low-ionization broad absorption line (LoBAL) QSOs have been found at high redshifts, to date. One high-redshift LoBAL QSO, J0122+1216, was recently discovered by the Lijiang 2.4 m Telescope, with an initial redshift determination of 4.76. Aiming to investigate its physical properties, we carried out follow-up observations in the optical and near-IR spectroscopy. Near-IR spectra from UKIRT and P200 confirm that it is a LoBAL, with a new redshift determination of 4.82 +/- 0.01 based on the Mg II emission-line. The new Mg II redshift determination reveals strong blueshifts and asymmetry of the high-ionization emission lines. We estimate a black hole mass of similar to 2.3 x 10(9) M-circle dot and Eddington ratio of similar to 1.0 according to the empirical Mg II-based single-epoch relation and bolometric correction factor. It is possible that strong outflows are the result of an extreme quasar environment driven by the high Eddington ratio. A lower limit on the outflowing kinetic power (>0.9% L-Edd) is derived from both emission and absorption lines, indicating that these outflows play a significant role in the feedback process that regulates the growth of its black hole, as well as host galaxy evolution.
27
Marble, Andrew R. „QSO Pairs and the Lyman-alpha Forest: Observations, Simulations, and Cosmological Implications“. Diss., The University of Arizona, 2007. http://hdl.handle.net/10150/193945.
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This dissertation addresses two cosmological applications of the Lyman-alpha (Ly ɑ) forest observed in QSO pairs separated by several arcminutes or less. The Ly ɑ flux autocorrelation and cross-correlation provide a measurement of cosmic geometry at z > 2, via a variant of the Alcock-Paczyński test. I present the results of an observing campaign to obtain moderate resolution spectroscopy of the Ly ɑ forest in QSO pairs with small redshift differences (Δz < 0.25) and arcminute separations (θ < 5'). This new sample includes 29 pairs and one triplet suitable for measuring the cross-correlation and 78 individual QSO spectra for determining the autocorrelation. Continuum fits are provided, as are seven revisions for previously published QSO identifications and/or redshifts. Using a suite of hydrodynamic simulations, anisotropies in the Ly ɑ flux correlation function due to redshift-space distortions and spectral smoothing are investigated for 1:8 ≤ z ≤ 3, further enabling future applications of the Alcock-Paczyński test with Ly ɑ correlation measurements. Sources of systematic error including limitations in mass-resolution and simulation volume, prescriptions for galactic outflow, and the observationally uncertain mean flux decrement are considered. The latter is found to be dominant. An approximate solution for obtaining the zero-lag cross-correlation for arbitrary spectral resolution is presented, as is a method for implementing the resulting anisotropy corrections while mitigating systematic uncertainty.
28
Matejek, Michael Scott. „Probing the early universe with the epoch of reionization and QSO spectroscopy“. Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/79521.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 185-198).
We present results from the first systematic survey for Mg ii absorption lines at z > 2.5. Using 46 infrared QSO spectra we discovered 111 Mg II systems, including five with z > 5- the most distant systems now known. The comoving line density for weaker systems is statistically consistent with no evolution from z = 0.4 to z = 5.5. The density for stronger systems increases three-fold until z ~ 3 before declining towards higher redshifts, suggesting a connection to star formation. The weaker systems' lack of evolution does not fit within this interpretation, but may be reproduced by extrapolating low redshift scaling relations between host galaxy luminosity and absorbing halo radius to earlier epochs. Using new measurements from optical spectra of the same targets and low redshift control samples we study evolutionary trends in the chemical composition of Mg ii systems from z = 0 --> 5.33. We observe a significant strengthening in the characteristic N(H I) for fixed Mg 11 strength as one moves toward higher redshift. We set lower limits on the metallicity where we can measure H 1, and find that systems with W₀ [delta]2796 = 0.3 - i.OA are quite metal rich at ~ 0.1 Solar. We speculate that if weaker Mg ii systems represent accreting gas, then their high metal abundance suggests re-accretion of recently ejected material rather than first-time infall from the metal-poor IGM, even at early times. We present a new technique for simultaneously fitting bright point sources in ungridded visibility data called the side lobe matrix technique. We provide computational speedups which allow for real time implementation. We derive analytic approximations for the error distributions of fit intensities in the presence of thermal noise, imperfect calibration, and ionospheric errors. We find that the intensity errors of the brightest sources with imperfect calibration and ionospheric errors are dominated by 'self errors' that exist independent of side-lobe contamination. We demonstrate that to lowest order, the dynamic range obtained with calibration/ionospheric errors is the same as when the source intensities are perfectly known.
by Michael Scott Matejek.
Ph.D.
29
Pan, Hongchao. „X-ray observations of SS 433 and the QSO MR 2251-178“. Thesis, University of Leicester, 1989. http://hdl.handle.net/2381/35754.
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This thesis reports the results of the X-ray observations of the galactic binary source SS 433 and the QSO MR 2251-178 made with the EXOSAT and GINGA X-ray satellites. The EXOSAT and GINGA study of SS 433 shows that both the X-ray intensity and spectrum of the binary vary over the periods of the 163 day jet precession and the 13 day binary motion. The X-ray luminosity of SS 433 is high at the phase corresponding to the maximum separation of the Doppler-shifted optical lines, and low when the jets become edge-on. An intensity decrease of up to 50% can be seen in each energy channel while the source changes from high to low luminosity. Over the 13 day binary cycle, the X-ray source is eclipsed by the companion star at the phase of the primary optical minimum. Five such events were observed by the EXOSAT and GINGA satellites at different phases of jet precession. The X-ray spectrum of SS 433 consists of a thermal continuum and a Doppler energy shifted broad emission line. It is proved, in this thesis, that the X-ray emission of SS 433 originates in the jets and is thermal in nature. The X-ray sources of SS 433 are stable and its properties are strongly modulated by the relativistic motion of the X-ray emitting material in the jets, the jet precession and the binary motion. With the constraints from the X-ray observations, a general picture of the X-ray jets of SS 433 is established in this thesis. The X-ray jets are a continuous super-sonic plasma flow and are generated inside the funnels of a thick accretion disc located around a black hole. Variable X-ray absorption and soft X-ray excess are found in the X-ray spectrum of MR 2251-178 with the EXOSAT observations. While there is an overall correlation between the ME(2-10 keV) and LE(0.1-2 keV) fluxes the pattern of variability can not be described by simple intensity, absorption or slope variations. It is shown, in this thesis, that it is possible to explain all the observed features by adopting the 'warm' absorber model in which the absorbing material is partially ionized by the flux of extreme ultra-violet and X-ray photons from the central continuum source. The preferred location of the absorbing material is close to the central continuum source. The recent evidence for 'cool' material in the centre of Seyfert galaxies is thus extended to include an object of significantly higher luminosity.
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Fiscone, Cristiana. „A machine learning approach to QSM: quantitative susceptibility map reconstruction with convolutional autoencoders“. Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/18047/.
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QSM (Quantitative Susceptibility Mapping) è un’ applicazione MRI, in grado di riprodurre, partendo da dati di fase di sequenze gradient echo, distribuzioni di suscettività magnetica dei tessuti. Con questa tecnica è possibile, ad esempio, caratterizzare e trattare malattie vascolari e neurodegenerative.
Per ottenere la mappa di suscettività, deve essere risolto un problema mal posto, dovuto alla presenza di singolarità all'interno dello spazio di Fourier. Sono state già implementate diverse tecniche per superare questa difficoltà, divise in: single-orientation methods (e.g. TKD) e multiple-orientation methods (e.g. COSMOS). I primi garantiscono una veloce ricostruzione, anche se molto rumorosa; i secondi invece richiedono lunghi tempi d’acquisizione, ma forniscono risultati accurati. Bisogna trovare un compromesso tra accuratezza e velocità per poter applicare QSM all'ambito clinico.
Una soluzione potrebbe essere un metodo che sfrutti tecniche di deep learning; per questo, abbiamo costruito una rete neurale con una struttura di fully convolutional autoencoder. La rete è stata addestrata tramite apprendimento supervisionato, utilizzando dati di fase come input, dati di suscettività ottenuti da COSMOS come labels e dati di suscettività ottenuti da TKD come controllo.
Dalle immagini dell’encefalo contenute nel database della QSM2016 Challenge, dati 2D e 3D sono stati estratti e processati. La distribuzione ottenuta con il nostro modello è stata confrontata con quella di COSMOS, considerata come gold-standard per la precisione nella ricostruzione: valutando intensità e contrasto in alcune regioni, sono emersi risultati tra loro consistenti. Le perfomance del network sono migliori di quelle di TKD.
Il risultato ottenuto è perciò soddisfacente: tramite machine learning, single-orientation method, è possibile quindi costruire velocemente una mappa di suscettività magnetica accurata tanto quanto quella risultante da approcci a multiple-orientation.
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Barbato, Eric. „GENETIC VARIATION NEAR CHRXQ22-Q23 IS LINKED TO EMOTIONAL FUNCTIONING IN CYSTIC FIBROSIS“. Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case1576069523062159.
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Hinoda, Takuya. „Quantitative assessment of gadolinium deposition in dentate nucleus using quantitative susceptibility mapping“. Kyoto University, 2018. http://hdl.handle.net/2433/232091.
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Frank, Stephan. „OVI Absorbers in SDSS Spectra“. The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1222116379.
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Siana, Brian D. „Optical-infrared selection of high redshift QSOs and the z = 3 QSO luminosity function /“. Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC IP addresses, 2005. http://wwwlib.umi.com/cr/ucsd/fullcit?p3205374.
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Quelen, Cathy. „La translocation chromosomique t(X;6) (p11;q23) dans la leucémie aigüe à basophiles“. Toulouse 3, 2011. http://thesesups.ups-tlse.fr/1650/.
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Les leucémies aiguës myéloblastiques de l'enfant sont des hémopathies malignes associées majoritairement à des translocations chromosomiques. La caractérisation moléculaire de ces réarrangements chromosomiques permet de mettre en évidence des gènes importants dans les processus de différenciation hématopoïétique. D'un point de vue clinique, la découverte de translocations récurrentes peut aider à la recherche de maladie résiduelle, établir des valeurs pronostiques et ainsi adapter la prise en charge du patient. La leucémie aiguë à basophiles (LAB) est un sous-type rare de leucémie aiguë myéloblastique. Malgré de rares cas de translocation t(X;6)(p11;q23) décrits dans cette pathologie, jusqu'alors, aucune caractérisation moléculaire n'avait été effectuée. Nos travaux ont porté sur la caractérisation des remaniements géniques associés à cette translocation. Nous avons recherché les modifications issues de cet événement chez 4 nourrissons de sexe masculin porteurs de la t(X;6). De part sa localisation en 6q23, l'implication du gène MYB était suspectée. A l'aide des techniques de Fluorescence in situ Hybridization et de Rapid Amplification of cDNA ends, des réarrangements chromosomiques complexes ainsi que l'existence d'un gène chimérique, MYB-GATA1, ont été respectivement mis en évidence dans les cas de LAB étudiés. De plus, la translocation t(X;6) est associée à une invalidation de l'unique allèle sauvage du gène GATA1 situé sur le chromosome X. Ces deux gènes sont des acteurs majeurs de l'hématopoïèse. En effet, GATA1 est indispensable à une érythropoïèse normale et MYB est impliqué, entre autre, dans l'auto-renouvellement des cellules souches hématopoïétiques et dans la différenciation des progéniteurs myéloïdes. Des tests clonogéniques sur des progéniteurs hématopoïétiques murins exprimant la protéine chimérique MYB-GATA1 ont permis de caractériser son impact sur la différenciation myéloïde. MYB-GATA1 induit à la fois l'engagement de ces cellules dans la lignée granulocytaire, et leur blocage à un stade précoce de différenciation. De plus, cette protéine de fusion augmente le pouvoir clonogène des cellules transduites. Pour la première fois, l'ensemble de nos résultats établit un lien de cause à effet entre une translocation chromosomique récurrente et le développement de LABChildhood acute myeloblastic leukemias are haematological malignancies frequently associated with chromosomal translocations. The molecular characterization of these chromosomal rearrangements highlights genes important in haematopoietic differentiation. Furthermore, the discovery of recurrent chromosomal translocation is essential for the detection of residual disease, establishment of prognostic value and therapeutic choices. Acute basophilic leukemia is a rare sub-type of acute myeloblastic leukaemia. Despite rare cases of t(X;6)(p11;q23) translocation reported for this pathology, no molecular characterization was available until recently. The aim of our work was to characterize genes rearrangement in four cases of male infants carrying t(X;6). Because of its location on chromosome 6q23, MYB was a good candidate gene. Our molecular investigations, based on fluorescence in situ hybridization and rapid amplification of cDNA ends, revealed a complex chromosomal rearrangement leading to the creation of a MYB-GATA1 fusion gene. Moreover, this translocation is associated with an invalidation of the GATA1 gene located on chromosome X. These two proteins are master regulators of haematopoiesis. GATA1 is essential for normal erythropoiesis and MYB is involved in hematopoietic stem cell renewal and myeloid differentiation. Expression of MYB-GATA1 in mouse lineage-negative cells committed them to the granulocyte lineage and blocked them at an early stage of differentiation. Moreover, this protein increased clonogenic potential. Taken together, these results establish, for the first time, a link between a recurrent chromosomal translocation and the development of this particular subtype of infant leukemia
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Wang, Kunrong. „High-Frequency Quasi-Single-Stage (QSS) Isolated AC-DC and DC-AC Power Conversion“. Diss., Virginia Tech, 1998. http://hdl.handle.net/10919/29394.
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The generic concept of quasi-single-stage (QSS) power conversion topology for ac-dc rectification and dc-ac inversion is proposed. The topology is reached by direct cascading and synchronized switching of two variety of buck or two variety of boost switching networks. The family of QSS power converters feature single-stage power processing without a dc-link low-pass filter, a unidirectional pulsating dc-link voltage, soft-switching capability with minimal extra commutation circuitry, simple PWM control, and high efficiency and reliability.
A new soft-switched single-phase QSS bi-directional inverter/rectifier (charger) topology is derived based on the QSS power conversion concept. A simple active voltage clamp branch is used to clamp the otherwise high transient voltage on the current-fed ac side, and at the same time, to achieve zero-voltage-switching (ZVS) for the switches in the output side bridge. Seamless four-quadrant operation in the inverter mode, and rectifier operation with unity power factor in the charger (rectifier) mode are realized with the proposed uni-polar center-aligned PWM scheme. Single-stage power conversion, standard half-bridge connection of devices, soft-switching for all the power devices, low conduction loss, simple center-aligned PWM control, and high reliability and efficiency are among its salient features. Experimental results on a 3 kVA bi-directional inverter/rectifier prototype validate the reliable operation of the circuit. Other single-phase and three-phase QSS bi-directional inverters/rectifiers can be easily derived as topological extensions of the basic QSS bi-directional inverter/rectifier.
A new QSS isolated three-phase zero-voltage/zero-current-switching (ZVZCS) buck PWM rectifier for high-power off-line applications is also proposed. It consists of a three-phase buck bridge switching under zero current and a phase-shift-controlled full-bridge with ZVZCS, while no intermediate dc-link is involved. Input power and displacement factor control, input current shaping, tight output voltage regulation, high-frequency transformer isolation, and soft-switching for all the power devices are realized in a unified single stage. Because of ZVZCS and single-stage power conversion, it can operate at high switching frequency while maintaining reliable operation and achieving higher efficiency than standard two-stage approaches. A family of isolated ZVZCS buck rectifiers are obtained by incorporating various ZVZCS schemes for full-bridge dc-dc converters into the basic QSS isolated buck rectifier topology. Experimental and simulation results substantiate the reliable operation and high efficiency of selected topologies.
The concept of charge control (or instantaneous average current control) of three-phase buck PWM rectifiers is introduced. It controls precisely the average input phase currents to track the input phase voltages by sensing and integrating only the dc rail current, realizes six-step PWM, and features simple implementation, fast dynamic response, excellent noise immunity, and is easy to realize with analog circuitry or to integrate. One particular merit of the scheme is its capability to correct any duty-cycle distortion incurred on only one of the two active duty-cycles which often happens in the soft-switched buck rectifiers, another merit is the smooth transition of the input currents between the 60o sectors. Simulation and preliminary experimental results show that smooth operations and high quality sinusoidal input currents in the full line cycle are achieved with the control scheme.Ph. D.
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Deverdun, Jérémy. „A la recherche de biomarqueurs vasculaires issus de l’IRM multimodale : mise en place d’un protocole expérimental et d’outils de modélisation associés“. Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS175.
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L'imagerie par résonance magnétique (IRM) permet maintenant d'observer différents types de tissus avec des résolutions de plus en plus fines. L'arbre vasculaire artériel et veineux est explorable et les flux peuvent y être caractérisés de façon non invasive. Le versant artériel de l'arbre vasculaire peut être obtenu par une imagerie dite par « temps de vol » et le versant veineux par une imagerie en contraste de phase. Le développement de reconstructions de cartographies de susceptibilité magnétique (QSM) permet d'améliorer le niveau de détails atteignable sur les veines en fournissant en plus la possibilité de quantifier des paramètres physiologiques comme la saturation veineuse en oxygène. La mise en place d'algorithmes et outils dédiés permet la reconstruction in-silico d'une architecture cohérente sujet-spécifique. Par ailleurs grâce à l'emploi de séquences de la dynamique telles que le contraste de phase dynamique et l'imagerie par marquage des protons artériels du sang, les débits artériels, veineux, et perfusionnels sont mesurables. L'intégralité de ces acquisitions est non invasive, donc applicable à l'intégralité des sujets passant des IRM. Sur la base de ces données anatomiques et dynamiques, un modèle complet et sujet-spécifique de l'hydrodynamique intracrânienne est proposé. Le flux sanguin et cérébro-spinal est décrit dans ce modèle par les équations bilans fondamentales de l'hydrodynamique : conservation de la masse, conservation de la quantité de mouvement. Pour tenir compte de l'adaptation du diamètre des vaisseaux aux pressions on introduit pour chaque compartiment un paramètre d'élasticité de la paroi et une équation correspondante. Grâce aux données d'imagerie IRM, les compartiments sanguins des artères aux veines, le parenchyme cérébral et le système ventriculaire sont inclus. Le modèle permet de simuler la répartition des flux et des pressions dans les différents compartiments de la vascularisation du patient ainsi que d'évaluer les effets d'occlusions localisées sur l'ensemble de l'architectureThe magnetic resonance imaging (MRI) allows the observation of various kind of tissues with always increasing resolution. The arterial and venous vascular trees can be explored, and the flows can be characterized in a noninvasive way. As an example, the arterial part of the tree can be obtained using so-called “Time Of Flight” MRI, and the venous part with phase contrast techniques. The development of quantitative susceptibility maps (QSM) improves the level of details achievable regarding veins; furthermore, it provides a new way to estimate physiological parameters such as venous saturation in oxygen. Eventually the implementation of dedicated algorithms and tools allows the in-silico reconstruction of a subject-specific coherent architecture. Moreover, due to the use of dynamic imaging sequences such as the dynamic phase contrast imaging and the arterial spin labeling, the arterial, venous and cerebral blood flow are measurable. All of these sequences are noninvasive and so usable on every subjects. Based on these anatomical and dynamics data, a full subject-specific model of the brain hydrodynamics is proposed here. The blood and cerebrospinal flow are described using basic balance equations of the hydrodynamics: continuity and momentum. To take into account of the adaptation of vessel diameter to the pressure, a wall elasticity parameter is added for each compartment together with the corresponding equation. Thanks to the MRI data, all the blood compartments, from arteries to vein, the cerebral parenchyma and the ventricular system are included. The model is able to simulate the flow and pressure repartition in all compartments of the subjects as well as show the impact of a located occlusion on the whole architecture
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Gansonre, Yassia. „Contribution à la mise en place d'une chaine qualité pour la conception, la réalisation et la gestion des infrastructures routières au Burkina Faso“. Thesis, Université Clermont Auvergne (2017-2020), 2018. http://www.theses.fr/2018CLFAC059.
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Au Burkina Faso, pays enclavé, pays agricole et minier, la mobilité est essentiellement assurée par les infrastructures routières qui couvrent près de 90% des besoins de transport. De ce fait, la politique de l’état burkinabé vise à renforcer le réseau existant et de désenclaver le pays, conscient du fort lien entre le développement du pays et le développement du réseau routier. Cependant, il est possible de noter une dégradation précoce du réseau routier. Lesquels phénomènes sont récurrents dans la zone intertropicale, notamment d’Afrique et sont parfois liés aux facteurs environnementaux (trafic, climat et matériaux) et aux procédures de conception, de réalisation et d’entretien des routes. Le travail a consisté à analyser la chaine complète de réalisation des routes depuis l’avant-projet jusqu’à l’entretien, afin de mettre en évidence les dysfonctionnements et de proposer des solutions permettant de les améliorer. Ainsi le travail s’est appuyé sur des études expérimentales, analytiques et sur des études socio-économiques qui ont permis enfin de comprendre et de mettre en place une chaine qualité adaptée au contexte socio-économique du paysIn Burkina Faso, landlocked country, agricultural and mining country, mobility is mainly ensured by the road infrastructures which cover nearly 90% of the transport needs. So the policy of the Burkina Faso’s state is relatively to reinforce the existing road network and to disenclose the country, conscious of the strong link between the development of the country and the development of the road network. However, it is possible to note an early degradation of the road network. Which phenomena are recurrent, in particular in the intertropical countries of Africa, and, are sometime related to the environmental factors (traffic, climate and materials) and to the procedures of design, construction and maintenance of roads. The study is consisted in analyzing the complete chain of realization roads since the preliminary draft until maintenance, in order to highlight the dysfunctions and to suggest solutions making it possible to improve them. Thus, the study was based on experimental, analytical and on socio-economic studies which finally made it possible to understand and to implement a QSE chain adapted to the socio-economic context of the country
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Pettazzoni, Laura. „Il Sistema di Gestione Integrata QSA per la miniera di acque termominerali di Porretta Terme“. Master's thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amslaurea.unibo.it/930/.
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SANTOS, MARCO ANTONIO CETALE. „PHASE-SHIFT DEPTH MIGRATION FOR QP AND QSV WAVEFIELDS ON LOCALLY TRANSVERSE ISOTROPIC (LTI) MEDIA“. PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2003. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=4373@1.
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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOEste trabalho propõe uma técnica do tipo rotação de fase para migração em profundidade de dados sísmicos para meios com simetria polar local (localmente transversalmente isotrópicos, LTI), nos quais a direção do eixo de simetria varia continuamente ao longo das camadas. São testadas, através de simulações numéricas de levantamentos sísmicos, a precisão e a estabilidade do método, em função da variação do eixo de simetria. Para a realização das simulações, desenvolveu-se um método a partir da solução da equação elástica da onda usando-se a técnica das diferenças finitas, que possibilita a modelagem em meios LTI, onde cada ponto da malha tem suas características definidas pelas velocidades de fase P e SV, parâmetros de Thomsen, densidade e inclinação do eixo de simetria. Na separação dos modos de onda qP e qSV dos sismogramas, implementou-se um algoritmo baseado na solução da equação de Christoffel para determinar os operadores de separação. A migração para cada família de tiro comum é realizada por soluções da equação da onda usando somente técnicas de rotações de fase. De fato, tanto a depropagação do campo registrado quanto a geração das matrizes de tempo utilizadas na condição de imageamento, são realizadas por soluções que envolvem rotações de fase para cada conjunto de parâmetros, em cada nível de profundidade. Nos resultados das migrações usando reflexões dos tipos qP-qP, e qP-qSV, os horizontes foram localizados precisamente e verificou-se que o processo é estável em relação à variação do eixo de simetria. Vale ressaltar que o método não está restrito a aquisições sísmicas multicomponentes, podendo ser aplicado em dados sísmicos marítimos convencionais, como também em dados provenientes de aquisições do tipo OBC (Ocean Bottom Cable) e com cabo vertical. Como o método proposto se baseia em algoritmos que utilizam técnicas de rotação de fase, a sua implementação conta com o beneficio de ser altamente paralelizável.
This work proposes a technique based on the phase-shift method to implement pre-stack depth migration on locally transverse isotropic media (LTI), in which the direction of the symmetry axis varies continually along the layers. Through numerical seismic data simulations the methods robustness and stability were tested in relation to the axis symmetry variations. For seismic modeling, a generalization of the finite differences method for the solution of the elastic wave equation was used. With this procedure, it was possible to accommodate seismic modeling on LTI media defined by six parameters at each grid point, i.e., density, P and S wave propagation velocities along the local symmetry axis, Thomsen parameters and, the direction of the local symmetry axis itself. In order to separate from the seismograms the qP and qSV wavefields, an algorithm based on the Christoffel equation was implemented. The migration for each common shot gather is implemented solely by phase-shift based algorithms, which means that not only the depropagation of the registered wavefield, but also the generation of the time matrices involved in the imaging condition were obtained in this manner for each set of parameters at each depth level. The migration results using qP-qP and qP-qSV reflections show that the horizons were located precisely, and that the process is stable in relation to the symmetry axis variations. The proposed method is not restricted to multicomponent seismic acquisitions, but it can be applied to marine seismic data using streamers, or Ocean Bottom Cables or vertical cables. Since the proposed method uses phaseshift algorithms, its parallel implementation can be highly efficient.
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MARQUET, SANDRINE. „Evidences pour un role de la region 5q31-q33 dans la susceptibilite aux infections parasitaires“. Clermont-Ferrand 2, 1997. http://www.theses.fr/1997CLF21899.
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Les bilharzioses qui infectent plusieurs centaines de millions d'etres humains sont associees a une mortalite elevee et a des souffrances considerables. L'etude d'une population du nord est bresilien a permis a notre laboratoire de faire la part entre les facteurs environnementaux et les facteurs de l'hote dans le determinisme des niveaux d'infection et a suggere l'existence d'un gene majeur qui controlerait ce phenotype. Le principal objectif de notre travail a ete de localiser ce gene en utilisant une approche de recherche systematique sur l'ensemble du genome de 150 sujets. Les marqueurs d5s636 et csf1r ont permis de localiser ce gene sm1 dans la region 5q31-q33 contenant de nombreux genes impliques dans la differenciation des lymphocytes-t auxiliaires. Ceci est compatible avec l'analyse immunologique des memes sujets montrant une association entre la resistance/susceptibilite a l'infection et une reponse t auxiliaire de type th0/2/th0/1. L'interleukine 5 produite par les lymphocytes th0/2 est essentielle a la production des eosinophiles dont le nombre est tres augmente chez les sujets infectes par des vers. Notre groupe avait, par analyse de segregation obtenu de fortes evidences pour un controle des niveaux de production d'il5 par un gene majeur. Nous avons entrepris sa localisation et avons obtenu un lod score suggestif d'une liaison entre un marqueur, d4s428, du chromosome 4 et ce gene. Nous avons entrepris l'identification de sm1 en recherchant si un ou plusieurs polymorphismes au sein de genes candidats presents dans l'intervalle de localisation de sm1 pourraient expliquer le phenotype niveau d'infection. L'ensemble de ces resultats indique que le developpement de la resistance humaine a s. Mansoni depend en grande partie des effets du gene sm1 qui intervient probablement dans le controle de la reponse immune au niveau de la differenciation des lymphocytes t auxiliaires. L'hypothese actuellement testee est que le locus 5q31-q33 joue un role important non seulement dans les bilharzioses mais egalement dans d'autres infections telle que le paludisme.
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Cochran, Pamela A. „Q Code, Text, and Signs: A Study of the Social Semiotic Significance of QSL Cards“. University of Findlay / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=findlay1484321999467252.
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Kokkonen, H. (Hannaleena). „Genetic changes of chromosome region 15q11-q13 in Prader-Willi and Angelman syndromes in Finland“. Doctoral thesis, University of Oulu, 2003. http://urn.fi/urn:isbn:9514270274.
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Abstract
The Prader-Willi (PWS) and Angelman (AS) syndromes are clinically distinct developmental disorders which are caused by genetic defects in the imprinted domain at chromosome 15q11-q13, resulting in the loss of paternal (PWS) or maternal (AS) gene function. In this study, the genetic changes of 15q11-q13 and their possible inheritance in Finnish PWS (n=76) and AS (n=47) patients are described. The diagnosis could be confirmed by laboratory methods in all PWS and in 43 (91%) AS patients.
A deletion of 15q11-q13 accounted for 76% of the PWS and 67% of the AS patients in whom a specific genetic defect had been established. The origin of deletion was always paternal in PWS and maternal in AS. In PWS, deletions of four different sizes were detected, while in AS only type I or II deletions were found. The smallest overlap of deletions/critical region detected was from locus D15S13 to locus D15S10 in PWS and from locus D15S128 to locus D15S12 in AS. A rare recurrence of del(15)(q11q13) due to maternal germ line mosaicism is described.
Maternal uniparental disomy of chromosome 15 accounted for 21% of PWS patients and paternal UPD for 2% of AS patients. In PWS, most UPD cases were due to errors in maternal meiosis (87%), most commonly leading to maternal heterodisomy (MI error). In AS, a rare error in the second segregation of paternal meiosis was found. UPD was associated with advanced maternal age, the mean being 34.6 years.
Imprinting defects were found in 3% of PWS (two non-IC-deletions) and 11% of AS (IC deletion in one sib pair and three non-IC-deletions) patients. In the case with IC deletion, the mutation was seen in several generations. The non-deletion cases were thought to be due to a de novo prezygotic or postzygotic error. In the non-deletion PWS cases, the maternally imprinted paternal chromosome region was shown to have been inherited from the paternal grandmother, while in AS the paternally imprinted maternal chromosome region had been inherited from either the maternal grandfather or the maternal grandmother. The region of IC involved in AS was defined to be 1.15 kb.
Five (11%) AS patients with normal DNA methylation test results had a UBE3A mutation. One of the two novel missense mutations (902A→C) had been inherited from the mosaic mother, while the mutation 975T→C was a new one. De novo deletions 1930delAG and 3093delAAGA have also been described previously, suggesting that these sites may be mutation hotspots in UBE3A.
Identification of different genetic aetiologies with different recurrence risks is essential for genetic counselling, and close co-operation between clinicians and the laboratory is required both for diagnosis and for the detection of possible inheritance.
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Silva, Shirley Margareth Buffon da. „A moral em questões sociocientíficas no ensino de biologia“. reponame:Repositório Institucional da UnB, 2016. http://repositorio.unb.br/handle/10482/22248.
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Tese (doutorado)—Universidade de Brasília, Faculdade de Educação, Programa de Pós-Graduação em Educação, 2016.Submitted by Fernanda Percia França (fernandafranca@bce.unb.br) on 2016-12-02T14:56:08Z No. of bitstreams: 1 2016_ShirleyMargarethBuffondaSilva.pdf: 3222308 bytes, checksum: 53786de30dcdc460dc998b2007a9771d (MD5)
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Esta tese é o resultado de uma investigação realizada com estudantes no 2º ano do ensino médio em uma escola pública do Distrito Federal. O objetivo foi desenvolver sequências didáticas com a introdução de questões sociocientíficas (QSC) relativas a dilemas da biotecnologia que envolvem aspectos morais, visando caracterizar implicações pedagógicas para tratar questões morais no ensino de Biologia. Para isso, foram identificados aspectos morais adotados pelos estudantes relativos às QSC, antes, durante e depois da discussão dos dilemas, com o propósito de encontrar possíveis indicadores da relação entre abordagem de QSC e aspectos morais. A investigação tomou como referência pesquisas empíricas e estudos sobre inserção curricular de QSC e moral, bem como estudos no campo da psicologia e da filosofia. As sequências didáticas desenvolvidas foram sobre os seguintes dilemas morais: alimentos transgênicos, clonagem e terapia gênica. As teorias morais normativas e a metaética foram o referencial teórico utilizado na análise dos dados. No caso dos princípios morais nos embasamos na Declaração Universal de Bioética e dos Direitos Humanos e Valores do Espírito do Desporto. Foi realizada uma abordagem investigativa de cunho qualitativo utilizando-se a análise textual discursiva para identificar categorias emergentes nos discursos dos atores, obtidos por meio de questionários, entrevistas e após o desenvolvimento de uma sequência didática com discussões de QSC. Os dados construídos apontaram que a maioria dos estudantes interpreta QSC sobre temas da biotecnologia com base nas teorias morais deontológica e utilitarista e também no ceticismo moral. Nas QSC sobre alimentos transgênicos a moral utilitarista foi a mais utilizada. Já no caso da clonagem e da terapia gênica a moral deontológica foi predominante, com um pequeno número de estudantes que apresentaram ceticismo moral. Nesse contexto, percebemos que as aplicações da biotecnologia abordadas foram analisadas de formas diferentes em termos de moralidade por parte dos estudantes, e que fatores como o contexto, emoções, existência de valores protegidos e sagrados podem ter influenciado o julgamento moral. Além disso, concluímos que com a realização da sequência didática houve mudanças nas percepções dos estudantes quanto a algumas categorias utilizadas na análise como, uso de alimentos transgênicos, consciência ecológica e percepção de risco. Os dados demonstram também que não houve uma mobilização significativa dos estudantes nos debates das QSC. A análise do desenvolvimento das sequências didáticas aponta dificuldades para se incluir aspectos morais em discussões de QSC, tais como a inserção de atividades didáticas apropriadas para desenvolver a participação dos estudantes em QSC e o contexto curricular da escola. Defendemos como tese que a introdução de aspectos morais em QSC é essencial no ensino de Biologia para que se prepare os estudantes na tomada de decisão moral. Para que isso ocorra no contexto curricular da maioria das escolas brasileiras, muitos desafios precisam ser enfrentados tais como a formação de professores e o desenvolvimento de estratégias de ensino variadas dentro da diversidade de cenários existentes. Em síntese, esta investigação identificou elementos para o entendimento de como discussões de QSC no ensino de Biologia podem contribuir para o favorecimento do raciocínio moral dos estudantes.
This thesis is the result of an investigation carried out with students in the 2nd year of high school in a public school in the Federal District. The goal was to develop didactic sequences with the introduction of socio-scientific issues (SSI) concerning biotechnology dilemmas involving moral aspects, aiming to characterize pedagogical implications to address moral issues in Biology teaching. To achieve this goal, moral aspects adopted by students regarding SSI were identified, before, during and after the discussion of the dilemmas in order to find out possible indicators of the relationship between SSI approach and moral issues. The investigation used, as reference, empirical researches and studies on curricular inclusion of SSI and moral, as well as studies on moral in the fields of psychology and philosophy. The developed didactic sequences involved the following moral dilemmas regarding biotechnology SSI: GM food, cloning and gene therapy. The normative moral theories and meta-ethics were the theoretical framework used in the data analysis. In the case of moral principles we relied on the principles of the Universal Declaration of Bioethics and of Human Rights, and in the case of genetic doping, on the Values of Sport Spirit. An investigative approach of qualitative nature, using discursive textual analysis, was performed to identify emerging categories in the speeches of the actors, obtained through questionnaires, interviews and after the development of a didactic sequence with SSI discussions. The obtained data showed that most students interpret SSI on biotechnology having as a basis moral deontological, utilitarian theories and moral skepticism. In SSI on GM food utilitarian moral was the most used. In the case of cloning and genetic therapy, deontological moral was predominant. A small number of students showed moral skepticism. In this context, we realize that the discussed applications of biotechnology were analyzed in different ways, in terms of morality, by part of the students, and that factors such as the context, emotions, existence of protected and sacred values may have influenced their moral judgment. Furthermore, we noticed that, with the completion of the didactic sequence, there were changes in the perceptions of the students regarding some categories used in the analysis, such as the use of GM food, ecological awareness and risk perception. The data also show that there was not a significant mobilization of the students in the SSI discussions. The analysis of the development of the didactic sequences points out several difficulties to introduce moral aspects in SSI discussions, such as appropriate didactic activities to develop the participation of the students in SSI and the curricular context of the school. We defend the thesis that the introduction of moral aspects of SSI is essential in Biology teaching to prepare students for in their moral decision-making. To attain this goal, in the curricular context of most Brazilian schools, many challenges need to be faced, such as teachers’ proficiency and the development of various teaching strategies within the diversity of the actual scenarios. In summary, this research identified elements for understanding how SSI discussions in Biology teaching may contribute to foster the moral reasoning of the students.
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Botti, Rojas Ismael Andrés. „Monitoreo Óptico de Causares Luminosos de Alto Redshift“. Tesis, Universidad de Chile, 2011. http://www.repositorio.uchile.cl/handle/2250/102676.
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Martins, Ana Patrícia da Silva Cunha. „Análise de pressupostos para definição de um modelo interno no âmbito da solvência II“. Master's thesis, Faculdade de Ciências e Tecnologia, 2009. http://hdl.handle.net/10362/8381.
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Zhu, Ying. „Deletion of chromosome bands 11q22-q23 in lymphoproliferative disorders and the genetics of mantle cell lymphoma“. Helsinki : University of Helsinki, 2002. http://ethesis.helsinki.fi/julkaisut/laa/haart/vk/zhu/.
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Kirkman, David. „The physical properties of the redshift three intergalactic medium from studies of QSO absorption line systems /“. Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC IP addresses, 1999. http://wwwlib.umi.com/cr/ucsd/fullcit?p9917953.
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McDonell, Nathalie. „Identification of a candidate gene for leukaemogenesis associated with an isocentric X chromosome [idic(X)(q13)]“. Paris 5, 2000. http://www.theses.fr/2000PA05C009.
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L'anomalie cytogénétique acquise consistant en un chromosome X isodicentrique [idic(X)(q13)] est associée chez des femmes âgées soit à une leucémie myéloi͏̈de aigue͏̈ (AML) soit à un syndrome myélodysplasique (MDS), souvent accompagnées d'une anémie sidéroblasique. L'existence d'autres anomalies cytogénétiques acquises impliquant Xq13 et associées à la MDS/AML, et l'identification d'un locus en Xq13 associé à une anémie sidéroblastique héréditaire, suggèrent fortement l'implication dans ces maladies myéloi͏̈des d'au moins un gène localisé en Xq13. Une étude précédente a permis de localiser, chez des patientes souffrant de myélodysplasie, les points de cassure de deux chromosomes idic(X)(q13) acquis dans une région de 450 kb proximale au gène XIST. Cette thèse décrit l'élaboration d'un contig de cosmides, PACs et BACs couvrant la région d'intérêt sur 1Mb et la caractérisation approfondie de cette région par séquençage à grande échelle et fibre-FISH. Une concentration exceptionnellement forte d'éléments répétitifs (LINE) et de nombreuses duplications ont été mises en évidence dans cette région génomique très complexe et pourraient expliquer l'instabilité génomique sous-jacente responsable de la formation itérative du chromosome isodicentrique Xq13. Le séquençage complet de la région a permis la localisation de plusieurs gènes et pseudogènes (PHKA1, NAP1L2, HDAC8, PABPP1&2, MAGE) de séquences exprimées et d'un marqueur polymorphe octanucléotidique qui coségrège avec la maladie dans deux familles souffrant d'anémie sidéroblastique. Les analyses réalisées par FISH sur les chromosomes en métaphase de six patientes idic(X)(q13)/MDS ou AML en utilisant comme sondes les clones du contig ont montré que tous les points de cassure étaient situés dans un intervalle couvert entièrement par un BAC. L'analyse de la séquence du BAC a permis le clonage d'un gène dont l'expression est probablement pertubée par l'anomalie génétique. Etant donné qu'il s'agit de la seule séquence exprimée identifiée dans la région des points de cassure, celle-ci représente un excellent gène candidat pour les troubles hématopoi͏̈étiques associés à une anomalie en Xq13. La confirmation de cette hypothèse pourrait par ailleurs contribuer à une meilleure compréhension du mécanisme moléculaire complexe menant au syndrome myélodysplasique et à la leucémie myéloi͏̈de aigue͏̈.
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Ippoliti, Matteo [Verfasser]. „Development and optimization of methods for quantitative Magnetic Resonance Imaging: QSM and DCE-MR / Matteo Ippoliti“. Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2021. http://d-nb.info/1241539871/34.
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