Artículos de revistas: "Alpha variation"

1

MOON, MARY ANN. "Alpha-Synuclein Gene Variation Associated With Parkinson's". Clinical Psychiatry News 34, n.º 11 (noviembre de 2006): 44. http://dx.doi.org/10.1016/s0270-6644(06)71903-8.

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2

Dunn, D. S., B. Madhoo, R. Turnbull y T. Jenkins. "Alpha-1-Antitrypsin Variation in Southern Africa". Human Heredity 36, n.º 4 (1986): 238–42. http://dx.doi.org/10.1159/000153633.

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3

Şengül, Hacer, Hüseyin Çakallı y Mikail Et. "A variation on strongly ideal lacunary ward continuity". Boletim da Sociedade Paranaense de Matemática 38, n.º 7 (14 de octubre de 2019): 99–108. http://dx.doi.org/10.5269/bspm.v38i7.46136.

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The main purpose of this paper is to introduce the concept of strongly ideal lacunary quasi-Cauchyness of order (alpha,beta) of sequences of real numbers. Strongly ideal lacunary ward continuity of order (alpha,beta) is also investigated. Interesting results are obtained.

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4

Kunicki, TJ, R. Orchekowski, D. Annis y Y. Honda. "Variability of integrin alpha 2 beta 1 activity on human platelets". Blood 82, n.º 9 (1 de noviembre de 1993): 2693–703. http://dx.doi.org/10.1182/blood.v82.9.2693.2693.

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Abstract The activity and surface antigenicity of alpha 2 beta 1 on platelets from 27 normal subjects were found to vary significantly. A fourfold range of surface antigen correlates with a 20-fold variation in the ability of nonactivated, washed platelets to adhere to type I collagen and a fivefold variation in the adhesion of platelets to type III collagen. These differences in surface receptor are reflected in significant variation in the lag time required for type I collagen- induced platelet aggregation in platelet-rich plasma. Among the same individuals, no difference was observed in surface levels or activities of two other platelet integrins, the fibronectin receptor alpha 5 beta 1 and the fibrinogen receptor alpha IIb beta 3. In all cases studied, we observed complimentary differences in the incorporation of 125I into surface alpha 2 beta 1, in quantity of surface alpha 2 beta 1 antigens, and in alpha 2 beta 1 collagen receptor activity. Despite variations in these parameters, there was no difference in the electrophoretic mobility or isoelectric point of either integrin subunit among the individuals studied. The wide range of activity and antigenicity of this platelet collagen receptor may result from polymorphism(s) in the alpha 2 beta 1 genes, or the activity of alpha 2 beta 1 may be variably regulated by another gene product. The heterogeneity of platelet alpha 2 beta 1 that we describe in this report certainly explains previous discrepancies concerning the contributions of this integrin to platelet adhesion to collagens. Most importantly, differences in surface collagen receptor activity may correlate with a long-term risk toward thrombosis, impaired hemostasis, and/or cardiovascular disease.

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5

Kunicki, TJ, R. Orchekowski, D. Annis y Y. Honda. "Variability of integrin alpha 2 beta 1 activity on human platelets". Blood 82, n.º 9 (1 de noviembre de 1993): 2693–703. http://dx.doi.org/10.1182/blood.v82.9.2693.bloodjournal8292693.

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The activity and surface antigenicity of alpha 2 beta 1 on platelets from 27 normal subjects were found to vary significantly. A fourfold range of surface antigen correlates with a 20-fold variation in the ability of nonactivated, washed platelets to adhere to type I collagen and a fivefold variation in the adhesion of platelets to type III collagen. These differences in surface receptor are reflected in significant variation in the lag time required for type I collagen- induced platelet aggregation in platelet-rich plasma. Among the same individuals, no difference was observed in surface levels or activities of two other platelet integrins, the fibronectin receptor alpha 5 beta 1 and the fibrinogen receptor alpha IIb beta 3. In all cases studied, we observed complimentary differences in the incorporation of 125I into surface alpha 2 beta 1, in quantity of surface alpha 2 beta 1 antigens, and in alpha 2 beta 1 collagen receptor activity. Despite variations in these parameters, there was no difference in the electrophoretic mobility or isoelectric point of either integrin subunit among the individuals studied. The wide range of activity and antigenicity of this platelet collagen receptor may result from polymorphism(s) in the alpha 2 beta 1 genes, or the activity of alpha 2 beta 1 may be variably regulated by another gene product. The heterogeneity of platelet alpha 2 beta 1 that we describe in this report certainly explains previous discrepancies concerning the contributions of this integrin to platelet adhesion to collagens. Most importantly, differences in surface collagen receptor activity may correlate with a long-term risk toward thrombosis, impaired hemostasis, and/or cardiovascular disease.

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6

Salter, D. M., J. L. Godolphin y M. S. Gourlay. "Chondrocyte heterogeneity: immunohistologically defined variation of integrin expression at different sites in human fetal knees." Journal of Histochemistry & Cytochemistry 43, n.º 4 (abril de 1995): 447–57. http://dx.doi.org/10.1177/43.4.7897185.

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During development and at maturity different forms of cartilage vary in morphology and macromolecular content. This reflects heterogeneity of chondrocyte activity, in part involving differential interactions with the adjacent extracellular matrix via specialized cell surface receptors such as integrins. We undertook an immunohistological study on a series of human fetal knee joints to assess variation in the expression of integrins by chondrocytes and potential matrix ligands in articular, epiphyseal, growth plate, and meniscal cartilage. The results show that articular chondrocytes (beta 1+, beta 5 alpha V+, alpha 1+, alpha 2+/-, alpha 5+, weakly alpha 6+, alpha V+) differed from epiphyseal (beta 1+, beta 5 alpha V+, alpha 1+/-, alpha 2+/-, alpha 5+, alpha 6+, alpha V+) growth plate (beta 1+, beta 5 alpha V+, alpha 1-, alpha 2-, alpha 5+, alpha 6+, alpha V+), and meniscal cells (beta 1+, beta 5 alpha V+, alpha 1+, strongly alpha 2+, alpha 5+, alpha 6+, alpha V+ in expression of integrin subunits. There was no expression of beta 3, beta 4, beta 6, or alpha 3 by chondrocytes. These results differ from previous reports on the expression of integrins by adult articular cartilage, where alpha 2 and alpha 6 are not seen. Variation in distribution of matrix ligands was also seen. Fibronectin, laminin and Type VI collagen were expressed in all cartilages but there was restricted expression of tenascin, ED-A and ED-B fibronectin isoforms (articular cartilage and meniscus), and vitronectin (absent from growth plate cartilage). Regulated expression of integrins by chondrocytes, associated with changes in the pericellular matrix composition, is of potential importance in control of cartilage differentiation and function in health and disease.

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7

Ohno, Ichiro. "Temperature Variation of Elastic Properties of .ALPHA.-Quartz up to the .ALPHA.-.BETA. Transition." Journal of Physics of the Earth 43, n.º 2 (1995): 157–69. http://dx.doi.org/10.4294/jpe1952.43.157.

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8

MENEZES, J., C. SANTOS y P. P. AVELINO. "GRAVITATIONAL EFFECTS OF VARYING ALPHA STRINGS". International Journal of Modern Physics A 21, n.º 16 (30 de junio de 2006): 3295–306. http://dx.doi.org/10.1142/s0217751x06031430.

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We study spatial variations of the fine-structure constant in the presence of static straight cosmic strings in the weak-field approximation in Einstein gravity. We work in the context of a generic Bekenstein-type model and consider a gauge kinetic function linear in the scalar field. We determine an analytical form for the scalar field and the string metric at large distances from the core. We show that the gravitational effects of α-varying strings can be seen as a combination of the gravitational effects of global and local strings. We also verify that at large distances to the core the space–time metric is similar to that of a global string. We study the motion of test particles approaching from infinity and show that photons are scattered to infinity while massive particles are trapped in bounded trajectories. We also calculate an overall limit on the magnitude of the variation of α for a GUT string, by considering suitable cosmological constraints coming from the Equivalence Principle.

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9

Claeyssens, A., J. Richard, J. Blaizot, T. Garel, F. Leclercq, V. Patrício, A. Verhamme et al. "Spectral variations of Lyman $\alpha$ emission within strongly lensed sources observed with MUSE". Monthly Notices of the Royal Astronomical Society 489, n.º 4 (10 de septiembre de 2019): 5022–29. http://dx.doi.org/10.1093/mnras/stz2492.

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ABSTRACT We present an analysis of ${\rm H\,\rm{\small {I}}}$ Lyman $\alpha$ emission in deep VLT/MUSE observations of two highly magnified and extended galaxies at $z=3.5$ and 4.03, including a newly discovered, almost complete Einstein ring. While these Lyman $\alpha$ haloes are intrinsically similar to the ones typically seen in other MUSE deep fields, the benefits of gravitational lensing allow us to construct exceptionally detailed maps of Lyman $\alpha$ line properties at sub-kpc scales. By combining all multiple images, we are able to observe complex structures in the Lyman $\alpha$ emission and uncover small ($\sim120$ km s−1 in Lyman $\alpha$ peak shift), but significant at $ \gt $4 $\sigma$, systematic variations in the shape of the Lyman $\alpha$ line profile within each halo. Indeed, we observe a global trend for the line peak shift to become redder at large radii, together with a strong correlation between the peak wavelength and line width. This systematic intrahalo variation is markedly similar to the object-to-object variations obtained from the integrated properties of recent large samples. Regions of high surface brightness correspond to relatively small line shifts, which could indicate that Lyman $\alpha$ emission escapes preferentially from regions where the line profile has been less severely affected by scattering of Lyman $\alpha$ photons.

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10

Hauck, Ekkehard W., Arne Hauptmann, Simone M. Haag, Anette Bohnert, Wolfgang Weidner, Gregor Bein y Holger Hackstein. "Alpha-1-Antitrypsin Levels and Genetic Variation of the Alpha-1-Antitrypsin Gene in Peyronie’s Disease". European Urology 46, n.º 5 (noviembre de 2004): 623–28. http://dx.doi.org/10.1016/j.eururo.2004.04.028.

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11

Takayanagi, Issei, Shuji Onozuka y Katsuo Koike. "Variation in Sensitivity of .ALPHA.1-Adrenoceptor Stimulants and .ALPHA.1-Adrenoceptor Mechanisms in Rabbit Arteries." Japanese Journal of Pharmacology 55, n.º 4 (1991): 513–22. http://dx.doi.org/10.1254/jjp.55.513.

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12

Smit, Christine M., Margaret J. Wright, Narelle K. Hansell, Gina M. Geffen y Nicholas G. Martin. "Genetic variation of individual alpha frequency (IAF) and alpha power in a large adolescent twin sample". International Journal of Psychophysiology 61, n.º 2 (agosto de 2006): 235–43. http://dx.doi.org/10.1016/j.ijpsycho.2005.10.004.

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13

Peng, Weiwei, Yilin Zhan, Yali Jiang, Wenya Nan, Roi Cohen Kadosh y Feng Wan. "Individual variation in alpha neurofeedback training efficacy predicts pain modulation". NeuroImage: Clinical 28 (2020): 102454. http://dx.doi.org/10.1016/j.nicl.2020.102454.

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14

Calvert, Laura, Helen Atkinson, Leslie Berry y Anthony Chan. "Age-Dependent Variation in Glycosylation Features of Alpha-2-Macroglobulin". Cell Biochemistry and Biophysics 77, n.º 4 (5 de septiembre de 2019): 335–42. http://dx.doi.org/10.1007/s12013-019-00883-4.

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15

AMIMOTO, K., Y. SASAKI, S. FUKUYAMA y Y. TAMURA. "Genetic variation and cross-reactivity of Clostridium septicum alpha-toxin". Veterinary Microbiology 114, n.º 1-2 (16 de abril de 2006): 51–59. http://dx.doi.org/10.1016/j.vetmic.2005.10.039.

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16

MULLOOLY, VIRGINIA M., ALLAN L. ABRAMSON, BETTIE M. STEINBERG y MARILYN S. HOROWITZ. "CLINICAL EFFECTS OF ALPHA-INTERFERON DOSE VARIATION ON LARYNGEAL PAPILLOMAS". Laryngoscope 98, n.º 12 (diciembre de 1988): 1324???1329. http://dx.doi.org/10.1288/00005537-198812000-00008.

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17

Bertoin, Jean. "Sur Une Integrale Pour Les Processus A $\alpha$-Variation Bornee". Annals of Probability 17, n.º 4 (octubre de 1989): 1521–35. http://dx.doi.org/10.1214/aop/1176991171.

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18

Whitehouse, David B., Jenny U. Lovegrove y David A. Hopkinson. "Variation in alpha-1-antitrypsin phenotypes associated with penicillamine therapy". Clinica Chimica Acta 179, n.º 1 (enero de 1989): 109–15. http://dx.doi.org/10.1016/0009-8981(89)90028-4.

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19

GIORDANI, Paolo, Giorgio BRUNIALTI, Marco CALDERISI, Paola MALASPINA y Luisa FRATI. "Beta diversity and similarity of lichen communities as a sign of the times". Lichenologist 50, n.º 3 (mayo de 2018): 371–83. http://dx.doi.org/10.1017/s0024282918000221.

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AbstractCurrently, change in lichen community structure depends on a combination of several pollutants instead of just one. Consequently, alpha lichen diversity no longer represents an effective response variable for assessing trends in atmospheric pollutants over time. Here we investigated the value of the relationship between alpha diversity and different aspects of gamma diversity (similarity, replacement and differences in richness of species) together with that of beta diversity (calculated as the sum of replacement and difference in richness of species), for assessing complex variations in epiphytic lichen communities in response to a changing pollution scenario. We considered an area subjected to extreme variation in atmospheric pollution in recent decades and explored temporal and spatial aspects of lichen community succession over short-, intermediate- and long-term reference periods. We found that variation in lichen communities for long- and intermediate-term reference periods was strongly dependent on the alpha diversity of single trees at the beginning of the observation period. The occurrence of nitrophytic species, which responded to the decrease in SO2 concentrations, contribute to this trend. The effect of land use was observed only over long observation periods, with trees in urban areas showing less variation than those located in rural areas. In particular, the analysis of similarity, species replacement and differences in richness of tree pairs demonstrated that trends and patterns within lichen communities are neither always nor to the same extent associated with alpha diversity. Our results show that a thorough study of gamma diversity, including beta diversity and similarity, is required to detect changes in air quality in long-term biomonitoring surveys.

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20

Gupta, Rajendra P. "Cosmology with relativistically varying physical constants". Monthly Notices of the Royal Astronomical Society 498, n.º 3 (25 de agosto de 2020): 4481–91. http://dx.doi.org/10.1093/mnras/staa2472.

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ABSTRACT We have shown that the varying physical constant model is consistent with the recently published variational approach wherein Einstein equations are modified to include the variation of the speed of light c, gravitational constant G, and cosmological constant Λ using the Einstein–Hilbert action. The general constraint resulting from satisfying the local conservation laws and contracted Bianchi identities provides the freedom to choose the form of the variation of the constants as well as how their variations are related. When we choose ${\dot{G}}/G = 3\,\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle\cdot}$}}{\dot{c}} /c,\,c = {c_0}\,{\rm{exp}}\,[({a^\alpha} - 1)],\,G = {G_0}\,{\rm{exp}}\,[3({a^\alpha} - 1)]$, and ${\rm{\Lambda }} = {{\rm{\Lambda }}_0}\ \exp [ {( {{a^{ - \alpha }} - 1} )} ]$, where a is the scale factor and α = 1.8, we are able to show that the resulting model: (a) fits the supernova 1a observational data marginally better than the Lambda cold dark matter (ΛCDM) model; (b) determines the first peak in the power spectrum of the cosmic microwave background temperature anisotropies at a multipole value of $l = 217.3$; (c) calculates the age of the Universe as 14.1 Gyr; and (d) finds the BAO acoustic scale to be 145.2 Mpc. These numbers are within less than 3 per cent of the values derived using the ΛCDM model. Surprisingly, we find that the dark-energy density is negative in a Universe that has significant negative curvature and whose expansion is accelerating at a faster rate than that predicted by the ΛCDM model.

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21

Fu, Yong-Bi, G. Peter Y. Clarke, Gene Namkoong y Alvin D. Yanchuk. "Incomplete block designs for genetic testing: statistical efficiencies of estimating family means". Canadian Journal of Forest Research 28, n.º 7 (1 de julio de 1998): 977–86. http://dx.doi.org/10.1139/x98-072.

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A half-sib progeny trial with single-tree plots on one test site of various environmental variations is simulated to examine the relative statistical efficiencies of randomized incomplete block designs (ICBs) over their corresponding randomized complete block design (RCB) in estimating family means. The ICBs with full constraint (FC), half constraint (HC), and no constraint (NC) over replicates and an alpha design (Alpha) are considered. A geostatistical spatial model is employed, which allows specifications of patchy and systematic environmental variations across the test site and estimations of block and error components with SAS PROC MIXED. The simulation shows that Alpha is the most efficient ICB in the 21 scenarios of patchy and systematic site variations, followed by NC and HC, and these ICBs (except FC) are generally more efficient than RCB in terms of the average variance of a family mean contrast. The gains in statistical efficiencies with implementations of Alpha and NC (rather than RCB) in forest genetic testing can be high, depending largely on the nature (and level) of spatial environmental variation. Practical implications of these simulated results for forest genetic trials are discussed.

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22

BARROW, JOHN D., JOÃO MAGUEIJO y HÅVARD BUNES SANDVIK. "CHANGING ALPHA: SOME MATTERS OF GRAVITY". International Journal of Modern Physics D 11, n.º 10 (diciembre de 2002): 1615–19. http://dx.doi.org/10.1142/s0218271802002980.

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We show how recent evidence for a small cosmological variation of the fine structure "constant" can be tested by local experiments which probe the behaviour of gravity. In particular, in the simplest theory, 'fifth force' experiments should see a positive effect with just an order of magnitude increase in current sensitivity. Space experiments should easily see the predicted effects.

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23

Hölzel, W. G. "Intra-individual variation of some analytes in serum of patients with insulin-dependent diabetes mellitus." Clinical Chemistry 33, n.º 1 (1 de enero de 1987): 57–61. http://dx.doi.org/10.1093/clinchem/33.1.57.

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Abstract Biological intra-individual variation in concentrations of 16 clinical biochemical analytes in serum was estimated for 27 patients with insulin-dependent diabetes mellitus (IDDM), and results were compared with those for apparently healthy individuals. In general, the variation was significantly higher in the patients. The ratio of the average intra-individual variation in IDDM patients to that in normal subjects exceeded 2.0 for Na+, K+, creatinine, and alpha-amylase; 1.50 to 2.0 for Cl-, total protein, albumin, cholesterol, and hemoglobin; and 1.2 to 1.5 for urea, uric acid, high-density-lipoprotein cholesterol, and aspartate aminotransferase. This increased variability in IDDM patients may be caused by variations in osmotic diuresis. Average intra-individual variations were greater for women than for men for Na+, total protein, albumin, and hemoglobin. Individual values showed a gaussian distribution for all analytes, including enzymes and triglycerides. No intra-individual variation was time dependent. For practical purposes, decision-making criteria in monitoring IDDM can be derived from the estimated biological component of intra-individual variation and the analytical variation established for each laboratory.

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24

SCARPASSA, V. M. y W. P. TADEI. "Enzymatic analysis in Anopheles nuneztovari Gabaldón (Diptera, Culicidae)". Revista Brasileira de Biologia 60, n.º 4 (noviembre de 2000): 539–50. http://dx.doi.org/10.1590/s0034-71082000000400002.

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Enzymatic analysis in Anopheles nuneztovari was made using four populations from the Brazilian Amazon and two from Colombia. The enzymes ME and XDH presented a monomorphic locus in all of the studied populations. EST and LAP presented a higher number of loci. In EST, genetic variation was observed in the five loci; LAP presented four loci, with allec variation in two loci. In IDH, three activity regions were stained, with genetic variation for locus Idh-1 in the Brazilian Amazon populations. A locus for MDH was observed, with genetic variation in the six populations. A region was verified for ACON, with four alleles in Sitronela and three in the other populations. PGM constituted one locus, with a high variability in the Brazilian Amazon populations. A locus was observed for 6-PGD with allelic variation in all of the populations with the exception of Tibú. Enzyme PGI presented two loci, both with genetic variability in the Tucuruí population. The enzyme alpha-GPD showed an activity region with polymorphism in the Tucuruí, Tibú and Sitronela populations. The phenotypic variations detected for these enzymes suggest that four (EST, LAP, ACON and PGM) possess monomeric structures and five (IDH, MDH, 6-PGD, PGI and alpha-GPD) dimeric structures in their proteins. These enzymes constitute in important markers to estimate variability and genetic divergence in natural populations of A. nuneztovari.

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25

Hauptmann, A., E. Hauck, A. Bohnert, S. Haag, W. Weidner, G. Bein y H. Hackstein. "732 Alpha-1-antitrypsin levels and genetic variation of the alpha-1-antitrypsin gene in Peyronie's disease". European Urology Supplements 3, n.º 2 (febrero de 2004): 186. http://dx.doi.org/10.1016/s1569-9056(04)90726-9.

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26

Zemel, Désirée, Raymond T. Krediet, Gerardus C. M. Koomen, Dirk G. Struijk y Lambertus Arisz. "Day-To-Day Variability of Protein Transport Used as a Method for Analyzing Peritoneal Permeability in CAPD". Peritoneal Dialysis International: Journal of the International Society for Peritoneal Dialysis 11, n.º 3 (julio de 1991): 217–23. http://dx.doi.org/10.1177/089686089101100306.

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The transperitoneal transport of macromolecules is dependent on both effective peritoneal surface area and intrinsic permeability of the peritoneum. For passage of small solutes, the effective surface area is the main determinant. We hypothesized that day-to-day variations in peritoneal clearances are caused by changes in the effective surface area and not in the intrinsic permeability. Four CAPD {continuous ambulatory peritoneal dialysis) patients without peritonitis were investigated on 28 consecutive days. Concentrations of beta-2-microglobulin, albumin, IgG, and alpha-2-macroglobulin were determined daily in dialysate {night bags) and weekly in serum. Clearances and their coefficients of variation were calculated. Mean coefficients of the intraindividual variation of protein clearances increased, the higher the molecular weight: they ranged from 12% for beta-2microglobulin clearance to 22% for alpha-2-macroglobulin clearance. Correlations were present between the clearances of albumin, IgG, and alpha-2-macroglobulin, but not between any of these and beta-2-microglobulin clearance. In all patients, protein clearance {C) was a power function of the free diffusion coefficient in water {D) according to the equation: C=a. Db in which b represents the restriction coefficient of the peritoneum, and thus intrinsic permeability. The coefficient of variation of the restriction coefficient was low (range 4–6%). This supports our assumption that the intrinsic permeability is fairly constant on the short term. Day-to-day variations in protein clearances are thus mainly caused by alterations in the effective peritoneal surface area. Longterm follow-up of the restriction coefficient in individual patients might identify those at risk for the development of structural changes in the peritoneal membrane.

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27

SOWARD, A. M. y P. H. ROBERTS. "On the derivation of the Navier–Stokes–alpha equations from Hamilton's principle". Journal of Fluid Mechanics 604 (14 de mayo de 2008): 297–323. http://dx.doi.org/10.1017/s0022112008001213.

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We investigate the derivation of Euler's equation from Hamilton's variational principle for flows decomposed into their mean and fluctuating parts. Our particular concern is with the flow decomposition used in the derivation of the Navier–Stokes–α equation which expresses the fluctuating velocity in terms of the mean flow and a small fluctuating displacement. In the past the derivation has retained terms up to second order in the Lagrangian which is then averaged. The variation is effected by incrementing the mean velocity, while holding the moments of the products of the displacements fixed. The process leads to a mean Euler equation for the mean velocity. The Navier–Stokes–α equation is only obtained after making a further closure approximation, which is not the concern of this paper. Instead attention is restricted here to the exact analysis of Euler's equation. We show that a proper implementation of Hamilton's principle, which concerns the virtual variation of particle paths, can only be achieved when the fluctuating displacement and mean velocity are varied in concert. This leads to an exact form of Euler's equation. If, on the other hand, the displacement is held fixed under the variation, a term in Euler's equation is lost. Averaging that erroneous form provides the basis of the Navier–Stokes–α equation. We explore the implications of the correct mean equation, particularly with regard to Kelvin's circulation theorem, comparing it with the so called GLM and glm-equations.

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28

Gussoli, M. K., J. C. D. de Oliveira y M. Higa. "INVESTIGATION ON VOLUME VARIATION FOR ALPHA STIRLING ENGINES ON ISOTHERMAL MODEL". Revista de Engenharia Térmica 19, n.º 2 (21 de diciembre de 2020): 10. http://dx.doi.org/10.5380/reterm.v19i2.78608.

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The usage of renewable energies is approximately 11% of the matrix energy worldwide. In countries known for its renewable sources, such as Brazil, the percentage is close to 38%. The importance to study Stirling engines and propose a prototype is that they are a feasible alternative for generation of power and electricity when considering low quality sources such as solar and waste energy. This paper will compare two different approaches of the volume variation, sinusoidal and kinematic, using an isothermal model that represents the Stirling engines. The comparison is made for an a type engine. Such approaches are capable of representing an estimative of work and power output for Stirling engines since the difference of results for these approaches are 8.07% for power output. As both approaches are a valid choice for analyzing the Stirling engine cycle, the availability of the data determines which approach is the most suitable for characterizing the engine performance.

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29

Blomqvist, Mia E. L., Niels Andreasen, Nenad Bogdanovic, Kaj Blennow, Anthony J. Brookes y Jonathan A. Prince. "Genetic variation in CTNNA3 encoding alpha-3 catenin and Alzheimer's disease". Neuroscience Letters 358, n.º 3 (abril de 2004): 220–22. http://dx.doi.org/10.1016/j.neulet.2004.01.032.

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30

TESSNOW1, K. "Circadian variation of topoisomerase II-alpha in human rectal crypt epithelium". American Journal of Gastroenterology 96, n.º 9 (septiembre de 2001): S168—S169. http://dx.doi.org/10.1016/s0002-9270(01)03308-1.

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31

Contreras-Aguilar, María D., Jerome Vialaret, Dominique Deville de Périère, Damián Escribano, Sylvain Lehmann, Fernando Tecles, Jose J. Cerón y Christophe Hirtz. "Variation of human salivary alpha-amylase proteoforms in three stimulation models". Clinical Oral Investigations 24, n.º 1 (6 de agosto de 2019): 475–86. http://dx.doi.org/10.1007/s00784-019-03021-9.

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32

Brennan, B. J. "Variation of the alpha dose rate to grains in heterogeneous sediments". Radiation Measurements 41, n.º 7-8 (agosto de 2006): 1026–31. http://dx.doi.org/10.1016/j.radmeas.2006.05.011.

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33

Bloemhof, E. E., W. C. Danchi y C. H. Townes. "Rapid variation in the circumstellar 10 micron emission of Alpha Orionis". Astrophysical Journal 299 (diciembre de 1985): L37. http://dx.doi.org/10.1086/184576.

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34

Anderson, D. y M. Lisak. "Variation of prompt alpha particle losses during sawtooth activity in Tokamaks". Plasma Physics and Controlled Fusion 32, n.º 2 (1 de febrero de 1990): 141–53. http://dx.doi.org/10.1088/0741-3335/32/2/005.

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35

Malafosse, Bruno De. "On the set of $ \alpha $, $ p $-bounded variation of order $ h $". Tamkang Journal of Mathematics 38, n.º 2 (30 de junio de 2007): 121–37. http://dx.doi.org/10.5556/j.tkjm.38.2007.83.

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Kömpf, J., J. Tomiuk, G. Feil, S. Lahme y K. H. Bichler. "Induratio penis plastica und genetische Variation des Alpha-1-Antitrypsin-Systems". Aktuelle Urologie 32, S1 (julio de 2001): 41–43. http://dx.doi.org/10.1055/s-2001-15959.

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37

Hu Jing-yao, Sun Jing-hao y Dong Yi-sun. "A rapid variation in the H-alpha profile of gamma cassiopeiae". Chinese Astronomy and Astrophysics 9, n.º 3 (septiembre de 1985): 259–60. http://dx.doi.org/10.1016/0275-1062(85)90048-7.

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38

Silva, Teomar Duarte da, Michele Trombin de Souza, Mireli Trombin de Souza, Roger Raupp Cipriano, Humberto Ribeiro Bizzo y Cicero Deschamps. "Essential Oil Variation in Brazilian Varronia curassavica Jacq. in Response to Drying and Edaphoclimatic Conditions". Journal of Agricultural Science 13, n.º 8 (15 de julio de 2021): 16. http://dx.doi.org/10.5539/jas.v13n8p16.

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Varronia curassavica Jacq. (Boraginaceae) is a native species of the Atlantic Forest with medical importance. This study determined the essential oil variation of 16 populations of V. curassavica of restinga in Santa Catarina, Brazil, in response to drying and edaphoclimatic conditions. The populations supplied essential oil with a content between 0.27 to 1.15% in the summer and from 0.33 to 1.12% in the winter. 41 chemical compounds were identified in the summer and 40 in the winter. The compounds were grouped into 4 chemical classes in each station studied. The common chemical constituents found in the essential oil of all populations and in both seasons were α-thujene, α-pinene, sabinene, α-humulene, (E)-cariophylene, spatulenol, mircene, allo-aromadendrene, β-sesquifelandreno and α-zingiberene. Cluster analysis using the nearest neighbor method based on Euclidean distance grouped the 16 populations into 3 groups in the summer and 8 groups in the winter. As the habitats have distinct pedological characteristics, we identified that pH, organic matter, sum of bases and base saturation are associated with the synthesis of (E)-caryophyllene, α-humulene, and allo-aromadendrene from populations.

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Gese, Eric M. y Robert L. Ruff. "Howling by coyotes ( Canis latrans): variation among social classes, seasons, and pack sizes". Canadian Journal of Zoology 76, n.º 6 (1 de junio de 1998): 1037–43. http://dx.doi.org/10.1139/z98-038.

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From January 1991 to June 1993 we observed 54 coyotes (Canis latrans) for 2507 h in Yellowstone National Park,Wyoming, during which we observed 517 howling events. Among coyotes of different types of social organization (residentversus transient), members of resident packs initiated or participated in howling events, while transient individuals were neverobserved howling (n = 51 h of observation). For members of resident packs, alpha coyotes spent more time howling and had ahigher rate of howling events than beta coyotes and pups; beta coyotes and pups howled similarly. The percentage of time andthe rate of howling events typically peaked in the dispersal and breeding seasons, with the lowest rate of howling during puprearing. Social rank and season did not influence the length of howling events. Pack size did not affect howling rates amongindividuals in a pack or the alpha pair. With respect to space-use patterns, coyotes in resident packs howled more frequentlythan expected along the periphery of the territory than in the core area. We concluded that, like wolves (Canis lupus), allcoyotes in the resident pack did not contribute equally to howling duties; alpha coyotes howled more than all coyotes. Howlingby coyotes appears to serve a territorial spacing function that is mainly performed by the alpha pair of the resident pack.

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40

Cheng, Dandong, Xiaotian Zhao, Jinxi Song, Haotian Sun, Shaoqing Wang, Haifeng Bai y Qi Li. "Quantifying the Distribution and Diversity of Fish Species Along Elevational Gradients in the Weihe River Basin, Northwest China". Sustainability 11, n.º 21 (5 de noviembre de 2019): 6177. http://dx.doi.org/10.3390/su11216177.

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In this study, species compositions, distributions, and diversity patterns of fish assemblages were investigated at 50 sampling sites in the Weihe River and its two largest tributaries, the Jinghe River and the Beiluo River, under high- and low-flow conditions in 2017. For every condition tested and in the all rivers tested, Cyprinidae was the richest family, containing 17 of the 39 identified fish species. Carassius auratus was the most common species, accounting for 11.3% of the total individuals. Nonmetric multidimensional scaling (NMDS), analysis of similarities (ANOSIM), and similarity percentage analysis (SIMPER) revealed that fish species composition differed significantly among rivers (p < 0.05), with dissimilar species assemblages found in the different rivers. Variation was influenced by a combined effect of habitat conditions, environmental factors, and human impact. Canonical correspondence analysis (CCA) identified variables explaining the variation in fish species (p < 0.05), and elevation contributed the most under both flow conditions. Alpha diversity decreased with increasing elevation within rivers as a result of changing environmental conditions, especially for wetted width. Alpha and beta diversities of rivers increased with increasing drainage area, which is related to habitat heterogeneity. The decrease in alpha diversity and the increase in beta diversity with increasing elevation can be explained by variations in habitat and geographic features.

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41

Adebambo, A. O., C. O. N. Ikeobi, M. O. Ozoje y O. A. Adebambo. "Variation in growth performance of pure and crossed meat type chickens". Nigerian Journal of Animal Production 36, n.º 2 (29 de diciembre de 2020): 211–27. http://dx.doi.org/10.51791/njap.v36i2.1302.

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Genetic variation from a combination of four breeds of chickens (Anak Titan, Alpha, Giriraja and Normal indigenous chickens) were examined for importance of sire, dam, season and sex on growth traits using a Mixed-model Least-Squares and Maximum LIkelihood computer program. The results show that sire and dam genotypes significantly (P<0.05) affected growth. Anak Titan cocks and hens performed best in body weight (BW) with values ranging from 38.45±0.74g and 40.21±0.66g at day old to 1135.93 35.67g and 953.38 35.38g at week 12 respectively. Normal indigenous and Alpha improved indigenous performed better in linear body parameters. Genetic correlation coefficients among parameters for all the breeds were generally high. Positive estimates ranged from 0.15 for breast girth (BG) and keel length (KL) at week four to 0.99 for BG-KL at week tweve while negative values ranged from -0.783 for body weight (BW) and wing length (WL) at week four to -0.99 for BW-BG at week twelve. Heritability estimates for body weight ranged from 0.14 at week one to 0.63 at week four. It can be concluded that appreciable variation exists for growth traits among the strains of chickens. Such variations can be utilized for improvement in the present emvironment.

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42

Vanga, Amaresh R., Samantha A. Schrier Vergano, Jolanta Kowalewska y Thomas R. McCune. "Previously Unidentified Gene Variation Associated with Fabry Disease: The Impact on One Family". Case Reports in Nephrology 2020 (19 de septiembre de 2020): 1–3. http://dx.doi.org/10.1155/2020/8899703.

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Fabry disease is an X-linked lysosomal storage genetic disorder associated with over 1000 mutations in the alpha-galactosidase-A gene region. We report here a 69-year-old male who underwent a kidney biopsy to evaluate progressive renal failure. He was found to have zebra bodies in visceral epithelial cells on biopsy, with electron microscopy showing inclusions within the cytoplasm of multiple podocytes consistent with Fabry disease. An alpha-galactosidase level was found to be 21 nm/hr/mg (normal range 50–150 nm/hr/mg). Genetic studies revealed a missense variant in the GLA gene with alanine replaced by cysteine at position 682 (c.682 A > C, p.N228H) that had not been previously associated with Fabry disease. The same variant was detected in two additional family members. The pathologic findings, clinical features, and low alpha-galactosidase level suggest that the c.682 A > C variant is associated with Fabry disease.

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Sepkoski, J. John. "Alpha, beta, or gamma: where does all the diversity go?" Paleobiology 14, n.º 3 (1988): 221–34. http://dx.doi.org/10.1017/s0094837300011969.

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Global taxonomic richness is affected by variation in three components: within-community, or alpha, diversity; between-community, or beta, diversity; and between-region, or gamma, diversity. A data set consisting of 505 faunal lists distributed among 40 stratigraphic intervals and six environmental zones was used to investigate how variation in alpha and beta diversity influenced global diversity through the Paleozoic, and especially during the Ordovician radiations. As first shown by Bambach (1977), alpha diversity increased by 50 to 70 percent in offshore marine environments during the Ordovician and then remained essentially constant for the remainder of the Paleozoic. The increase is insufficient, however, to account for the 300 percent rise observed in global generic diversity. It is shown that beta diversity among level, soft-bottom communities also increased significantly during the early Paleozoic. This change is related to enhanced habitat selection, and presumably increased overall specialization, among diversifying taxa during the Ordovician radiations. Combined with alpha diversity, the measured change in beta diversity still accounts for only about half of the increase in global diversity. Other sources of increase are probably not related to variation in gamma diversity but rather to appearance and/or expansion of organic reefs, hardground communities, bryozoan thickets, and crinoid gardens during the Ordovician.

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44

Zhang, Xianan, Mingshen Su, Jihong Du, Huijuan Zhou, Xiongwei Li, Xin Li y Zhengwen Ye. "Comparison of Phytochemical Differences of the Pulp of Different Peach [Prunus persica (L.) Batsch] Cultivars with Alpha-Glucosidase Inhibitory Activity Variations in China Using UPLC-Q-TOF/MS". Molecules 24, n.º 10 (22 de mayo de 2019): 1968. http://dx.doi.org/10.3390/molecules24101968.

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In order to fully understand the variation of the fruit alpha-glucosidase inhibitory activity-related phytochemical basis in the Chinese peach [Prunus persica (L.) Batsch], mature fruit from 33 cultivars was used for the investigation of fruit phenolic phytochemical attributes, including total phenolics, flavonoids, anthocyanins, and procyanidins, as well as the alpha-glucosidase inhibitory activity in vitro. Alpha-glucosidase inhibitory activity varied significantly among tested peach cultivars and was strongly correlated with total phenolics, total procyanidins, and total flavonoids. Untargeted UPLC-Q-TOF/MS-based metabolomics were used to comprehensively discriminate between peaches with different inhibitory activity on alpha-glucosidase. Principal component analysis (PCA) and orthogonal partial least squares discrimination analysis (OPLS-DA) were used for this process. Twenty-three differential compounds were identified between peach cultivars with high and low alpha-glucosidase inhibitory activity, and nine, including procyanidin C1, procyanidin trimer isomer 1, procyanidin trimer isomer 2, procyanidin B1, procyanidin dimer, epicatechin-epicatechin-epicatechin, phloridzin, kaempferol 3-(2’’,6’’-di-(E)-p-coumarylglucoside), and luteolin 3’-methyl ether 7-malonylglucoside, were identified as marker compounds responsible for the discrimination. Overall, variations in metabolites in peach pulp reflect the diversity in peach germplasm, and these nine compounds are good candidate markers for future genetic breeding of peach fruit with high alpha-glucosidase inhibitory activity.

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45

Bu, Qiang. "Benchmarking mutual fund alpha". American Journal of Business 31, n.º 4 (3 de octubre de 2016): 227–39. http://dx.doi.org/10.1108/ajb-01-2016-0001.

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Purpose The standard market models assume that all investors are rational with the same level of risk aversion, whereas investors in the real world are neither rational nor homogeneous. This contrast makes these models inappropriate for evaluating manager skill. The purpose of this paper is to attempt to bridge the gap between model assumption and fund investment practice. Design/methodology/approach This study proposes a series of modified models using the excess return of peer funds to estimate fund alpha. In these models, the market excess return in the standard market models is replaced with the average excess return of bootstrapped funds. In addition, the author examines the reasons for the difference between the modified models and the standard models. Findings The modified models better explain the variation of fund returns, and they exhibit that a considerably higher percentage of funds can earn positive alpha, thus the skill of fund managers is underestimated based on the standard market models. Originality/value The proposed models provide a more reliable method for investors to identify skilled fund managers, and they can also serve as an objective benchmark in evaluating fund performance and in designing manager compensation packages.

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46

Carra, G. y R. S. Accolla. "Structural analysis of human Ia antigens reveals the existence of a fourth molecular subset distinct from DP, DQ, and DR molecules." Journal of Experimental Medicine 165, n.º 1 (1 de enero de 1987): 47–63. http://dx.doi.org/10.1084/jem.165.1.47.

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Structural analysis by two-dimensional peptide maps (2D-PM) of the human Ia molecular pool expressed on the cell surface of two distinct lymphoblastoid cell line, LG-2 and Raji, revealed the existence of a novel MHC class II molecular heterodimer that differs at the level of both alpha and beta subunits from the previously described DP, DQ, and DR antigens. These differences were also seen at the level of two-dimensional electrophoresis (2D-PAGE) of biosynthetically labeled intact molecules, although to a lesser extent, due to the intrinsic limitations of this technique in resolving fine structural differences. We have designated this new class II antigen as the fourth Ia subset. The fourth Ia subset seems to represent a small proportion of the human Ia pool. Comparative analysis by 2D-PM of the two cell lines showed the presence of structural variations in the alpha chains of the fourth Ia subset, suggesting the existence of polymorphism for these subunits. Cell surface iodination did not show appreciable labeling of the fourth subset beta chain in LG-2 cells, and this prevented analysis of the structural polymorphism of this subunit. Furthermore, for the first time, we have shown that DP alpha chains display distinct peptide maps in LG-2 and Raji cells, thus suggesting the presence of structural polymorphism for these Ia subunits also. The DQ1 alpha and beta allelic products present in LG-2 cells (DQ homozygous) did not show appreciable structural variation when compared with the homologous allelic products present in Raji cells (DQ heterozygous). Finally, we have confirmed the absence of polymorphism for the DR alpha subunits. By 2D-PM, relatively low structural variation was instead found for the highly polymorphic DR beta subunits expressed in the two cell lines, suggesting that cell surface iodination preferentially labels constant domains of DR beta chains.

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Bevan, J., M. Oriowo y R. Bevan. "Physiological variation in alpha-adrenoceptor-mediated arterial sensitivity: relation to agonist affinity". Science 234, n.º 4773 (10 de octubre de 1986): 196–97. http://dx.doi.org/10.1126/science.3018932.

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Zaki, M. F., Tarek M. Hegazy, U. Seddik y A. Ahmed Morsy. "Variation of the track etch rates of alpha-particle trajectory in PADC". Radiation Effects and Defects in Solids 160, n.º 1-2 (enero de 2005): 53–58. http://dx.doi.org/10.1080/10420150500032416.

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49

Coizet, B., L. Nicoloso, D. Marletta, A. Tamiozzo-Calligarich, G. Pagnacco y P. Crepaldi. "Variation in Salivary and Pancreatic Alpha-Amylase Genes in Italian Horse Breeds". Journal of Heredity 105, n.º 3 (20 de febrero de 2014): 429–35. http://dx.doi.org/10.1093/jhered/esu005.

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50

Skinner, T. E., M. T. DeLand, G. E. Ballester, K. A. Coplin, P. D. Feldman y H. W. Moos. "Temporal variation of the Jovian H I Lyman alpha emission (1979–1986)". Journal of Geophysical Research 93, A1 (1988): 29. http://dx.doi.org/10.1029/ja093ia01p00029.

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