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Quantitative Characteristics (quantitative + characteristic)
Selected AbstractsShrimp (Pandalus borealis) growth and timing of the spring phytoplankton bloom on the Newfoundland,Labrador ShelfFISHERIES OCEANOGRAPHY, Issue 2 2007C. FUENTES-YACO Abstract We examined latitudinal and temporal changes in the availability of food for young shrimp (Pandalus borealis) on the Newfoundland,Labrador Shelf, using a suite of quantitative characteristics of the spring phytoplankton bloom determined from satellite ocean colour data, including bloom initiation time, maximum chlorophyll concentration, timing of the maximum, and bloom duration. We found significant correlations between bloom intensity, timing, and the size of young shrimp. The results are discussed in relation to the observation that, since the early 1990s, carapace lengths of shrimp have been decreasing in many Northwest Atlantic stocks. [source] Determination of essential oil quality index by using energy summation indices in an elite strain of Cymbopogon citratus (DC) Stapf [RRL(J)CCA12]FLAVOUR AND FRAGRANCE JOURNAL, Issue 2 2005Ashok Kumar Shahi Abstract Out of the several accessions of Cymbopogon citratus (DC) Stapf introduced from Central and West India, one accession coded as RRL(J)CCA12, selected through a mass selection technique, was found to have citral (,80%) as the major constituent in its essential oil. Citral has tremendous application in the ,avour and perfume industries. Plant adaptation was judged by quantifying the regression coef,cient (b) value, which was 1.0 using essential oil growth indices. For prediction of essential oil quality index (EOQI), a multiple regression equation was developed for the ,rst time by using essential oil yield/plant and energy summation indices as EOQI (citral %) = 61.6 + 1.09 × essential oil yield/plant (g) - 0.005 × heat use ef,ciency + 0.675 × phenothermal index. For obtaining a better quality of essential oil (citral ,78%), the optimal value of independent variable would be: X1 = 2.49; X2 = 0.018 and X3 = 20.47, where X1, X2 and X3 denote essential oil yield/plant, heat use ef,ciency and phenothermal index, respectively. The validation of the EOQI model is done by correlating the predicted and calculated values of citral (%) which exhibited signi,cant r value = 0.955 at 5% probability level. The thermal requirement of the selectant was ,5500 degree days to exhibit plant maturity in terms of qualitative and quantitative characteristics of its essential oil at 6.0 vegetative lea,ng stage, with attainment of plant height ,1.0 m from previous date of harvest (December 2001). Prediction of essential oil quality by using the mathematical model is helpful for integrating the growth processes and evaluating crop management strategies. Copyright © 2004 John Wiley & Sons, Ltd. [source] Quantitative analysis of anti,hepatitis C virus antibody,secreting B cells in patients with chronic hepatitis C,HEPATOLOGY, Issue 1 2006Takeji Umemura To investigate the quantitative characteristics of humoral immunity in patients with hepatitis C, we established an enzyme-linked immunosorbent spot (ELISpot) assay for detection of anti,hepatitis C virus (HCV)-secreting B cells. Receiver operating characteristic curve analysis demonstrated 100% specificity and 58% to 92% sensitivity for detecting B-cell responses to NS5b, NS3, E2, and core antigens. The median sum of anti-HCV,secreting B cells to all HCV antigens tested was significantly higher in 39 patients with chronic hepatitis C (47.3 spot forming cells [SFCs]/106 peripheral blood mononuclear cells [PBMCs]) than in 9 recovered subjects (15.3 SFCs/106 PBMCs; P = .05) or 11 uninfected controls (5.3 SFCs/106 PBMCs; P < .001); the significant difference (P = .018) in chronic versus recovered patients was in reactivity to nonstructural antigens NS3 and NS5b. Anti-HCV immunoglubulin M (IgM),secreting B cells were also readily detected and persisted decades into HCV infection; there was no difference in IgM-positive cells between chronic and recovered patients. ELISpot reactivity to genotype 1,derived antigens was equivalent in patients of genotypes 1, 2, and 3. There was significant correlation between the numbers of anti-HCV IgG-secreting B cells and serum aminotransferase and to the level of circulating antibody. In conclusion, ELISpot assays can be adapted to study B-cell as well as T-cell responses to HCV. Measurement at the single-cell level suggests that humoral immunity plays a minor role in recovery from HCV infection and that B-cell immunity is strongest in those with persistent infection. (HEPATOLOGY 2005.) [source] RPA repair recognition of DNA containing pyrimidines bearing bulky adducts,JOURNAL OF MOLECULAR RECOGNITION, Issue 3 2008Irina O. Petruseva Abstract Recognition of new DNA nucleotide excision repair (NER) substrate analogs, 48-mer ddsDNA (damaged double-stranded DNA), by human replication protein A (hRPA) has been analyzed using fluorescence spectroscopy and photoaffinity modification. The aim of the present work was to find quantitative characteristics of RPA,ddsDNA interaction and RPA subunits role in this process. The designed DNA structures bear bulky substituted pyrimidine nitrogen bases at the inner positions of duplex forming DNA chains. The photoreactive 4-azido-2,5-difluoro-3- pyridin-6-yl (FAP) and fluorescent antracenyl, pyrenyl (Antr, Pyr) groups were introduced via different linker fragments into exo-4N of deoxycytidine or 5C of deoxyuridine. J-dU-containing DNA was used as a photoactive model of undamaged DNA strands. The reporter group was a fluorescein residue, introduced into the 5,-phosphate end of one duplex-forming DNA strand. RPA,dsDNA association constants and the molar RPA/dsDNA ratio have been calculated based on fluorescence anisotropy measurements under conditions of a 1:1 RPA/dsDNA molar ratio in complexes. The evident preference for RPA binding to ddsDNA over undamaged dsDNA distinctly depends on the adduct type and varies in the following way: undamaged dsDNA,<,Antr-dC-ddsDNA,<,mmdsDNA,<,FAPdU-, Pyr-dU-ddsDNA,<,FAP-dC-ddsDNA (KD,=,68,±,1; 25,±,6; 13,±,1; 8,±,2, and 3.5,±,0.5,nM correspondingly) but weakly depends on the chain integrity. Interestingly the bulkier lesions not in all cases have a greater effect on RPA affinity to ddsDNA. The experiments on photoaffinity modification demonstrated only p70 of compactly arranged RPA directly interacting with dsDNA. The formation of RPA,ddsDNA covalent adducts was drastically reduced when both strands of DNA duplex contained virtually opposite located FAP-dC and Antr-dC. Thus RPA requires undamaged DNA strand presence for the effective interaction with dsDNA bearing bulky damages and demonstrates the early NER factors characteristic features underlying strand discrimination capacity and poor activity of the NER system toward double damaged DNA. Copyright © 2008 John Wiley & Sons, Ltd. [source] Magneto-electric effect on frequency mixing in atomsLASER PHYSICS LETTERS, Issue 7 2004V. D. Ovsiannikov Abstract Steady electric and magnetic fields can stimulate frequency mixing of two laser waves in ensemble of free atoms. In addition to coherence conditions, the steady fields may induce additional resonance singularities essentially enhancing the cross section for scattering the sum-frequency wave. Interference between different components of the electric- and magnetic-field induced frequency summation amplitudes may cause significant effects on the efficiency of conversion. The dependence on the incident wave polarization and the atomic resonance structure is calculated analytically for the frequency mixing in atoms with a singlet structure of the ground and resonance states. Numerical estimates for the quantitative characteristics of the effect are presented for helium, alkali-earth and mercury atoms in their ground n1S0 -state in the case of the two-photon resonance on excited singlet states with angular momentum 0, 1, and 2. (© 2004 by ASTRO, Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source] Variation of Apigenin Quantity in Diploid and Tetraploid Chamomilla recutita (L.) RauschertPLANT BIOLOGY, Issue 4 2000vehlíková Abstract: Apigenin, a pharmacologically important flavonoid of the chamomile plant, was analyzed at two ploidy levels during a three-year period. This flavonoid accumulates in the ligulate florets of the anthodium. Higher percentages of apigenin were found in the ligulate florets of a diploid cultivar, in comparison with tetraploid plants. However, when the total apigenin (mg of compound) in the anthodium was evaluated, tetraploid individuals accumulated significantly more flavonoid. Moreover, in contrast to morphological quantitative characteristics of the anthodium, which varied significantly in different years, apigenin percentage in the ligulate florets was constant and not influenced by environmental conditions. Apigenin content was also found to change during inflorescence ontogeny. It represents the highest percentage of dry mass in young developing florets and anthodia of both cultivars. The total apigenin content of the anthodium, however, increases during flowering, although at later stages apigenin forms only a minor part of ligulate floret and anthodium dry mass. [source] Parameterization of the CO2 and H2O gas exchange of several temperate deciduous broad-leaved trees at the leaf scale considering seasonal changesPLANT CELL & ENVIRONMENT, Issue 2 2003Y. KOSUGI ABSTRACT A combined model to simulate CO2 and H2O gas exchange at the leaf scale was parameterized using data obtained from in situ leaf-scale observations of diurnal and seasonal changes in the CO2 and H2O gas exchange of four temperate deciduous broad-leaved trees using a porometric method. The model consists of a Ball et al. type stomatal conductance submodel [Ball, Woodrow & Berry, pp. 221,224 in Progress in Photosynthesis Research (ed. I. Biggins), Martinus-Nijhoff Publishers, Dordrecht, The Netherlands, 1987] and a Farquhar et al. type biochemical submodel of photosynthesis (Farquhar, von Caemmerer & Berry, Planta 149, 78,90, 1980). In these submodels, several parameters were optimized for each tree species as representative of the quantitative characteristics related to gas exchange. The results show that the seasonal physiological changes of Vcmax25 in the biochemical model of photosynthesis should be used to estimate the long-term CO2 gas exchange. For Rd25 in the biochemical model of photosynthesis and m in the Ball et al. type stomatal conductance model, the difference should be counted during the leaf expansion period. [source] Brief communication: Paleohistopathological analysis of pathology museum specimens: Can periosteal reaction microstructure explain lesion etiology?AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 1 2009Darlene A. Weston Abstract The assertion that the microstructure of periosteal new bone formation can be used to differentiate between disease etiologies (Schultz: Yrbk Phys Anthropol 44 2001 106,147; Schultz: Identification of pathological conditions in human skeletal remains, 2nd ed. London: Academic Press 2003 73,109) was tested in a pilot-study, using diagnosed bone specimens from St George's Hospital Pathology Museum, London, UK. Embedded bone specimens exhibiting pathological periosteal new bone formation were examined using scanning electron microscopy in back-scattered electron imaging mode (SEM-BSE). The results suggest that several histological features (i.e. Grenzstreifen, Polsters, and sinuous lacunae) deemed to be diagnostic of specific pathological conditions are of no specific diagnostic value, as they are encountered in pathological conditions of differing disease etiology. These results tie in with a previous investigation demonstrating a lack of diagnostic qualitative or quantitative characteristics seen in the macroscopic and radiographic appearance of periosteal reactions (Weston: Am J Phys Anthropol 137 2008 48,59). Am J Phys Anthropol, 2009. © 2009 Wiley-Liss, Inc. [source] Influence of tank volume on vitellogenesis and spawning performances in sea bass Dicentrarchus labrax L.AQUACULTURE RESEARCH, Issue 4 2008Vincent Buchet Abstract Sea bass, Dicentrarchus labrax (mean weight: 748±13 g), were maintained before and during vitellogenesis in 1, 3, 8, 16 and 32 m3 tanks, and then they were transferred to 2 m3 tanks, for the spawning season. During the first 2 months of the experiment, the growth rates were significantly lower in smaller tanks (1 m3). In August, the oocyte diameters were significantly lower in smaller tanks (1, 3 and 8 m3) than in larger (16,32 m3) tanks. At the end of the experiment, the fish mean weight in the 1 m3 tanks was significantly lower than in the 3 m3 tanks, but oocyte diameters and plasma oestradiol concentrations were not significantly different between the volumes. This shows a longer acclimation requirement in smaller volume rearing. Although all the females had not spawned, one spawn at least was collected in each volume. The variation in conditioning volume has not blocked the spawning process. The qualitative and quantitative characteristics of spawns were not significantly different between volumes. The conditioning volume of 3 m3 seems to be a minimal volume required to obtain good reproduction of sea bass. [source] "Natural restoration" can generate biological complexityCOMPLEXITY, Issue 2 2005Emile ZuckerkandlArticle first published online: 16 DEC 200 Abstract Factor complexes engaged in transcriptional regulation of gene expression and their cognate DNA elements recurrently suffer mutational damage that can result in deadaptations in the mutual fit of interacting macromolecules. Such mutations can spread in populations by drift if their functional consequences are not severe. Mutational restorations of the damaged complexes may ensue and can take many forms. One of these forms would represent spontaneous increases in gene interaction complexity and correlated aspects of organismic complexity. In this particular mode of restoration, restabilization of a factor/factor/DNA complex occurs through the binding of an additional factor. Factors added under such circumstances to regulatory kits of individual genes are thought to be at the origin of a slow but persistent "complexity drive." This drive seems to be resisted in many forms whose developmental outcome has reached a finish line difficult to pass, but imposes itself along other lines of phylogenetic descent. In the process of restoration by an additional factor, the chances are significant that the original regulatory control of a target gene is not recovered exactly and that the restored gene expression has novel spatial, temporal, or quantitative characteristics. These new characteristics, which represent a functional transfer of the gene to a new domain of activity, may be selectable, even when the physicochemical properties of the gene product have remained largely unchanged. As a consequence of such activity transfers under quasi-constancy of the molecular properties of the protein encoded by the regulation's target gene, the activity domain originally covered by that target gene may be left at least in part functionally vacant. At that point, an unmodified duplicate of the target gene and of its original regulatory dependencies probably becomes in turn selectable. A causal link is therefore predicted between the regulatory specialization and selection of one of two duplicates and the regulatory maintenance and selection of the other. A conserved increase in gene number would result indirectly from the regulatory shift in paralogs, and the organism's complexity would be increased in this sense also, complexity as number of genes in addition to complexity as number of regulatory factors per gene. It is thus proposed that increased biological complexity, innovation in the gene regulatory network, and the development of a novel evolutionary potential can be the result, counterintuitively, of conservative forces that intervene when mutations play a survivable form of havoc with the system of gene regulation. Increasing complexity, then, could be seen as one of the side effects of "natural restoration." This phrase designates the mutational re-establishment in the gene whose regulation has been damaged of a functionally effective activity pattern, albeit, perhaps, with changes in its mode of expression in regard to location, time, and rate. The higher complexity, innovation in the gene regulatory network, of higher organisms,their very character of higher organisms,would to a significant extent be a side effect of episodes of natural selection aimed at functional restoration, not at complexity itself. Regulatory impairment, the point of departure of the process outlined, represents a controller gene disease. It thus may well be the case that molecular diseases, the effects on the individual of inheritable structural decay, are among the conditions of the evolution of higher organisms. © 2005 Wiley Periodicals, Inc. Complexity 11: 14,27, 2005 [source] | ||||||||||||||||