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Second Component (second + component)
Selected AbstractsMorphological variation in relation to flower use in bumblebeesENTOMOLOGICAL SCIENCE, Issue 2 2006Maki N. INOUE Abstract To understand resource partitioning in a bumblebee community, we analyzed various morphological characters. A total of 1269 individuals of six bumblebee species, Bombus ardens, B. hypocrita, B. diversus, B. ignitus, B. honshuensis and B. beaticola, were examined and principal component analysis showed that the bumblebee species were clearly differentiated. Glossa, prementa and head lengths were positively correlated with the second component, and a longer proboscis was associated with a narrower body, which may help bees to intrude into and access deep-lying nectar sources. Bombus diversus, with a long proboscis and narrow body, preferred flowers with a long corolla tube, whereas B. hypocrita and B. ignitus, which have short proboscises and wide bodies, visited flowers with short corollas or dish-shaped flowers. Two pairs of consubgeneric species that have similar morphological characteristics, B. ardens and B. beaticola, and B. hypocrita and B. ignitus, divided flower resources by habitat selection and seasonal partitioning. For resource partitioning among bumblebee species, not only morphology but also other factors, such as habitat and seasonal preference, flower use, foraging behavior, and interspecific interactions, are responsible. [source] INDIRECT GENETIC EFFECTS INFLUENCE ANTIPREDATOR BEHAVIOR IN GUPPIES: ESTIMATES OF THE COEFFICIENT OF INTERACTION PSI AND THE INHERITANCE OF RECIPROCITYEVOLUTION, Issue 7 2009Bronwyn H. Bleakley How and why cooperation evolves, particularly among nonrelatives, remains a major paradox for evolutionary biologists and behavioral ecologists. Although much attention has focused on fitness consequences associated with cooperating, relatively little is known about the second component of evolutionary change, the inheritance of cooperation or reciprocity. The genetics of behaviors that can only be expressed in the context of interactions are particularly difficult to describe because the relevant genes reside in multiple social partners. Indirect genetic effects (IGEs) describe the influence of genes carried in social partners on the phenotype of a focal individual and thus provide a novel approach to quantifying the genetics underlying interactions such as reciprocal cooperation. We used inbred lines of guppies and a novel application of IGE theory to describe the dual genetic control of predator inspection and social behavior, both classic models of reciprocity. We identified effects of focal strain, social group strain, and interactions between focal and group strains on variation in focal behavior. We measured ,, the coefficient of the interaction, which describes the degree to which an individual's phenotype is influenced by the phenotype of its social partners. The genetic identity of social partners substantially influences inspection behavior, measures of threat assessment, and schooling and does so in positively reinforcing manner. We therefore demonstrate strong IGEs for antipredator behavior that represent the genetic variation necessary for the evolution of reciprocity. [source] Fatigue-relevant stress field parameters of welded lap joints: pointed slit tip compared with keyhole notchFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 9 2009P. LAZZARIN ABSTRACT The notch stress intensity factor (NSIF) based analytical frame is applied to the slit tips (or weld roots) of welded joints with inclusion of the T-stress component. This T-stress can be determined from FE models evaluating the ligament stresses close to the pointed slit tip. An alternative analytical frame is presented for the corresponding keyhole notches based on analytical solutions from the literature, which are applied to the ligament stresses. In the slit tip models, the mean local strain energy density (SED) with inclusion of the T-stress effect is determined analytically and numerically in comparison, using two different fatigue-relevant control radii,,R0= 0.28 mm and,R0= 0.15 mm, the former value well proven for thick-sheet welded joints made of structural steel. The latter smaller value is tentatively proposed for thin-sheet welded joints, in the direction suggested in the recent literature where a reduction of the microstructural support length for laser beam welds and resistance spot welds is recommended. The FEM-based and analytical stress concentration factors (SCF) for the lap joint keyhole model and also the SED values for the corresponding pointed slit tips are found to be in good agreement. The,J -integral consisting of the first and second component (the latter containing the T-stress) is compared with the corresponding SED values. [source] , -Peptide Conjugates: Syntheses and CD and NMR Investigations of ,/, -Chimeric Peptides, of a DPA- , -Decapeptide, and of a PEGylated , -HeptapeptideHELVETICA CHIMICA ACTA, Issue 12 2009James Gardiner Abstract ,3 -Peptides consisting of six, seven, and ten homologated proteinogenic amino acid residues have been attached to an , -heptapeptide (all d- amino acid residues; 4), to a hexaethylene glycol chain (PEGylation; 5c), and to dipicolinic acid (DPA derivative 6), respectively. The conjugation of the , -peptides with the second component was carried out through the N-termini in all three cases. According to NMR analysis (CD3OH solutions), the (M)- 314 -helical structure of the , -peptidic segments was unscathed in all three chimeric compounds (Figs.,2, 4, and 5). The , -peptidic section of the ,/, -peptide was unstructured, and so was the oligoethylene glycol chain in the PEGylated compound. Thus, neither does the appendage influence the , -peptidic secondary structure, nor does the latter cause any order in the attached oligomers to be observed by this method of analysis. A similar conclusion may be drawn from CD spectra (Figs.,1, 3, and 5). These results bode well for the development of delivery systems involving , -peptides. [source] 8-Methyldecan-2-yl acetate inhibits response to the pheromone in the western corn rootworm Diabrotica v. virgiferaJOURNAL OF APPLIED ENTOMOLOGY, Issue 5 2010M. Tóth Abstract Compounds that are structurally closely related to the western corn rootworm (WCR) (Diabrotica v. virgifera, Coleoptera: Chrysomelidae) pheromone were prepared and screened for biological activity in the field, presented alone or in combination with the pheromone 8-methyldecan-2-yl propanoate. None of the synthetic compounds showed attraction when presented alone. However, when presented in combination with the pheromone, catches in traps containing 8-methyldecan-2-yl acetate as a second component were dramatically reduced, suggesting strong inhibitory activity for this compound. The addition of the inhibitory acetate to the known floral WCR lure (4-methoxycinnamaldehyde plus indole) did not influence male (or female) catches suggesting that the inhibitor interferes in the perception process of the pheromone and not by exerting repellency per se. To our knowledge, this is the first report on an inhibitor of response to pheromone in WCR. 8-Methyldecan-2-yl acetate has previously been described as a sex attractant of Diabrotica cristata, so its inhibitory activity towards males of WCR may reflect a role in maintaining reproductive isolation between the two taxa. [source] Effect of non-exponential and multi-exponential decay behavior on the performance of the direct exponential curve resolution algorithm (DECRA) in NMR investigationsJOURNAL OF CHEMOMETRICS, Issue 11 2003Todd M. Alam Abstract The effect of non-exponential and multi-exponential decay or relaxation behavior on the performance of the direct exponential curve resolution algorithm (DECRA) is investigated through a series of numerical simulations. Three different combinations of decay or relaxation behavior were investigated through DECRA analysis of simulated pulse gradient spin echo (PGSE) NMR diffusion spectra that contained the combination of two individual components. The diffusion decay behavior of one component was described by a single-exponential decay, while the second component was described by either (1) a multi-exponential decay, (2) a decay behavior described by the empirical Kohlrausch,Williams,Watts (KWW) relation or (3) a multi-exponential decay behavior correlated with variations in the NMR spectral line shape. The magnitudes and types of errors produced during the DECRA analysis of spectral data with deviations from a pure single-exponential decay behavior are presented. It is demonstrated that the deviation from single-exponential decay impacts the resulting calculated line shapes, the calculated relative concentrations and the quantitative estimation of the decay or relaxation time constants of both components present in the NMR spectra. Copyright © 2004 John Wiley & Sons, Ltd. [source] Michaelis-Menten Elimination Kinetics of Acetaldehyde During Ethanol OxidationALCOHOLISM, Issue 2002Tatsuya Fujimiya Background Acetaldehyde (AcH) is a toxic metabolite of ethanol (EtOH). The pharmacokinetics of blood AcH during EtOH oxidation was studied with or without the administration of aldehyde dehydrogenase 2 inhibitor (cyanamide) in rabbits. Methods An bolus of EtOH saline solution (0.25, 0.5, 1.0, 1.5, and 2.0 g/kg) was injected intravenously. Cyanamide was administered intraperitoneally (25 mg/kg body weight) to the cyanamide-treated group. Blood EtOH and AcH concentrations were measured by using head-space gas chromatography. Results In the control group, the first peak of the blood AcH appeared immediately and the second elevation appeared 1 to 4 hr after administration at a high EtOH dose. The blood AcH levels other than the second elevation part were significantly correlated to the blood EtOH levels. In the cyanamide-treated group, a peak and a plateau formed at the time corresponding to the second peak in the control group. The peak and plateau concentration of AcH increased markedly. We attempted simultaneous curve fitting, using the five blood EtOH and AcH concentration-time curves, to determine the pharmacokinetic model. Consequently, the AcH elimination was best described by a Michaelis-Menten kinetic model in both groups. Conclusions The blood AcH profile was suggested to consist of the first and second components that are related to the blood EtOH concentration itself and the metabolic formation of AcH, respectively. With higher EtOH doses or aldehyde dehydrogenase 2 inhibition, the second component becomes prominent as a result of the capacity-limited property of the metabolism of AcH, which is described by Michaelis-Menten elimination kinetics. [source] IS FISHING COMPATIBLE WITH ENVIRONMENTAL CONSERVATION: A STOCHASTIC MODEL WITH AN ELEMENT OF SELF-PROTECTIONNATURAL RESOURCE MODELING, Issue 3 2008D. AMI Abstract The purpose of this paper is to introduce the impact of fishing activity on a marine ecosystem. The fishing activity is considered not only through annual harvest but also through a second component, called the degree of protection of the fishery environment. This characterizes the environmental impact of fishing. A stochastic dynamic programming problem is presented in infinite horizon, where a sole owner seeks to maximize a discounted expected profit. The main hypothesis states that the stock,recruitment relationship is stochastic and that both components of the fishing activity have an impact on the probability law of the state of the fishery environment. The optimal fishing policy is obtained and compared with standard models. This optimal policy has the following properties: is not a constant escapement policy and indicates an element of self-protection by the fishery manager. The paper ends with a discussion on the existence of degrees of protection of the fishery environment that take into account the environmental conservation and preservation of economic activity. [source] Postulation of leaf-rust resistance genes in Czech and Slovak barley cultivars and breeding linesPLANT BREEDING, Issue 3 2000A. Dreiseitl Abstract Leaf-rust resistance (Rph) genes in 61 Czech and Slovak barley cultivars and 32 breeding lines from registration trials of the Czech Republic were postulated based on their reaction to 12 isolates of Puccinia hordei with different combinations of virulence genes. Five known Rph genes (Rph2, Rph3, Rph4, Rph7, and Rph12) and one unknown Rph gene were postulated to be present in this germplasm. To corroborate this result, the pedigree of the barley accessions was analysed. Gene Rph2, as well as Rph4, originated from old European cultivars. The donor of Rph3, which has been mainly used by Czech and Slovak breeders, is ,Ribari' (,Baladi 16'). Rph12 originates from barley cultivars developed in the former East Germany. Rph7 in the registered cultivar ,Heris' originates from ,Forrajera'. A combination of two genes was found in 10 cultivars. Nine heterogeneous cultivars were identified; they were composed of one component with an identified Rph gene and a second component without any resistance gene. No gene for leaf rust resistance was found in 17 of the accessions tested. This study demonstrates the utility of using selected pathotypes of P. hordei for postulating Rph genes in barley. [source] Photodegradation mechanism and stabilization of polyphenylene oxide and rigid-rod polymersPOLYMER INTERNATIONAL, Issue 2 2006Ying-Hung So Abstract Poly(2,4-dimethyl-1,4-phenylene oxide) (PPO), poly(benzo[1,2- d:5,4- d,]bisoxazole-2,6-diyl-1,4-phenylene) (PBO) and poly(benzo[1,2- d:4,5- d,]bisthiazole-2,6-diyl-1,4-phenylene) (PBZT), which are polymers with extended conjugated structures, undergo a self-sensitized photo-induced electron-transfer reaction. A second component is not required. This article presents many similar observations on these polymers when they are exposed to light and evidence to support the proposed photo-induced electron-transfer mechanism. Methods to stabilize these polymers against photo-oxidation are also described. Workers investigating other conjugated polymeric systems may find the experimental methods, observations and polymer stabilization approaches discussed in this review useful. Copyright © 2005 Society of Chemical Industry [source] A new polymorph of 2-methyl-6-nitroanilineACTA CRYSTALLOGRAPHICA SECTION C, Issue 10 2009Samantha K. Callear A new crystal form of 2-methyl-6-nitroaniline, C7H8N2O2, crystallizing with Z, = 2 in the space group P21/c, has been identified during screening for salts and cocrystals. The different N,H...O hydrogen-bonding synthons result in linear V-shaped chains in the new polymorph, rather than the helical chain arrangement seen in the known form where Z, = 1. The presence of a second component during crystallization appears to have determined the resultant crystal form of 2-methyl-6-nitroaniline. [source] A multi-wavelength view of the archetypical CSS radio galaxy 3C303.1: Evidence for shocks and induced star formationASTRONOMISCHE NACHRICHTEN, Issue 2-3 2009C.P. O'Dea Abstract I discuss multi-wavelength data on the archetypal CSS radio galaxy 3C303.1. The radio source is sub-galactic in scale where it can directly affect the ISM of the host galaxy. The emission line kinematics and ionization diagnostics are consistent with energy input from shocks driven by the radio source. The Spitzer IRS spectrum indicates that star formation is occurring in the host galaxy. The HST/ACS/HRC UV image shows UV light which is aligned with the radio source axis. I suggest that the UV light is from young stars which have been triggered by the radio lobes. XMM observations detect the ISM of the host galaxy with a temperature of 0.8 keV plus an additional component whose properties are not well defined. I suggest the second component is a hot shocked gas (T = 45 keV) consistent with a Mach number of 13 for the expanding bow shock. Thus, the multi-wavelength data give a consistent picture in which the radio source drives shocks into the ISM which ionize dense clouds, trigger star formation, and shock heat the hot component of the ISM to very high temperature. These observations demonstrate that radio sources can provide significant feedback to their host galaxy (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Isolation and purification of Thermus thermophilus HpaB by a crystallization approachACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 3 2010Tewfik Soulimane The oxygenase HpaB is a component of the 4-hydroxyphenylacetate 3-monooxygenase enzyme that is responsible for the hydroxylation of 4-hydroxyphenylacetate. It utilizes molecular oxygen and a reduced flavin, which is provided by HpaC, the second component of the enzyme. While isolating integral membrane respiratory complexes from Thermus thermophilus, microcrystals of HpaB were formed. Further purification of the enzyme was achieved by repetitive crystallization. Subsequently, well shaped single crystals of the native enzyme that diffract to 1.82,Å resolution were grown in sitting drops. They belong to the orthorhombic space group I222, with unit-cell parameters a = 91.3, b = 99.8, c = 131.7,Å. [source] Natural hybridization between Vanilla claviculata (W.Wright) Sw. and V. barbellata Rchb.f. (Orchidaceae): genetic, morphological, and pollination experimental dataBOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2000LENE ROSTGAARD NIELSEN Vanilla claviculata (W.Wright) Sw. and K barbellata Rchb.f. grow sympatrically in the southwestern part of herto Rico. At three localities in the range of the two species, individuals with flowers that appeared Merent from previously known species were found. To test whether these were hybrids between V. claviculata and V. barbellata, 11 morphological floral characters were recorded at seven populations and allozyme profiles of the three taxa compared. Principal component analysis on the morphological characters gave three distinct groups with minor overlaps. The first component axis reflects variation in overall size of the flowers, while the second component reflects variation in the size of the distal aperture of the labellum. Allozyme data revealed that the putative hybrids have a significant surplus of heterozygotes (FIS= - 0.65) as expected in a F1 generation. Both data sets support the hypothesis that the individuals are hybrids, which is further augmented by interspecific pollination experiments between the putative parental species. This is the first case of natural hybridization reported in the genus Vanilla. [source] Regional variation in electrically-evoked contractions of rabbit isolated pulmonary arteryBRITISH JOURNAL OF PHARMACOLOGY, Issue 4 2002V Margaret Jackson Electrically-evoked contractions in different regions of the rabbit isolated pulmonary artery have been investigated using stimulation parameters generally assumed to stimulate nerves selectively. In extrapulmonary artery, trains of stimuli (10 Hz; pulse width 0.1 ms) evoked monophasic contractions. In contrast, a biphasic contraction was evoked in the intrapulmonary artery consisting of an initial fast component followed by a secondary very long-lasting component. The contraction in the extrapulmonary artery was prazosin-sensitive (1 ,M) whereas that in the intrapulmonary artery was prazosin-resistant. ,,,-Methylene ATP (1 ,M), atropine (1 ,M), losartan (1 ,M), BIBO3304 (1 nM) or nifedipine (1 ,M) had no effect on the biphasic contraction of the intrapulmonary artery. Bretylium (2 ,M) abolished the contraction of extrapulmonary artery but only partially inhibited the initial component in the intra region with no effect on the second component. Tetrodotoxin (0.3,1 ,M), abolished the contraction of extrapulmonary artery but only partially reduced the electrically-evoked contraction of intrapulmonary artery. Removal of the endothelium and application of sulphisoxazole (0.6,22 ,M) had no effect. Varying the resting tone on the arteries, or applying gadolinium, had no effect on contractions. Using confocal microscopy and calcium imaging, reproducible whole cell calcium transients were evoked in individual smooth muscle cells in intact preparations but only when direct muscle stimulation was used (pulse width of 5,10 ms). No detectable changes in calcium were elicited when brief pulse widths were used (0.1,2 ms). Together, these data suggest that noradrenaline is the neurotransmitter inducing contraction in extrapulmonary artery. Noradrenaline and sympathetic nerves appear to play a less important role in the intrapulmonary artery. The tetrodoxin-resistant component is not mediated by ATP, NPY, acetylcholine, angiotensins, ET-1, stretch-activation or Ca2+ influx through L-type Ca2+ channels. Smooth muscle cells do not appear to be damaged by the stimulation protocol. The mechanism underlying the long lasting contraction of intrapulmonary artery evoked by brief electrical stimuli remains to be elucidated. British Journal of Pharmacology (2002) 137, 488,496. doi:10.1038/sj.bjp.0704863 [source] Induced choquet ordered averaging operator and its application to group decision makingINTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 1 2010Chunqiao Tan Yager (Fuzzy Sets Syst 2003;137:59,69) extended the idea of order-induced aggregation to the Choquet aggregation and defined a more general type of Choquet integral operator called the induced Choquet ordered averaging (I-COA) operator, which take as their argument pairs, in which one component called order-inducing variable is used to induce an ordering over the second components called argument variable and then aggregated. The aim of this paper is to develop the I-COA operator. Some of its properties are investigated. We show its relationship to the induced-ordered weighted averaging operator. Finally, we provide some I-COA operators to aggregate fuzzy preference relations in group decision-making problems. © 2009 Wiley Periodicals, Inc. [source] Michaelis-Menten Elimination Kinetics of Acetaldehyde During Ethanol OxidationALCOHOLISM, Issue 2002Tatsuya Fujimiya Background Acetaldehyde (AcH) is a toxic metabolite of ethanol (EtOH). The pharmacokinetics of blood AcH during EtOH oxidation was studied with or without the administration of aldehyde dehydrogenase 2 inhibitor (cyanamide) in rabbits. Methods An bolus of EtOH saline solution (0.25, 0.5, 1.0, 1.5, and 2.0 g/kg) was injected intravenously. Cyanamide was administered intraperitoneally (25 mg/kg body weight) to the cyanamide-treated group. Blood EtOH and AcH concentrations were measured by using head-space gas chromatography. Results In the control group, the first peak of the blood AcH appeared immediately and the second elevation appeared 1 to 4 hr after administration at a high EtOH dose. The blood AcH levels other than the second elevation part were significantly correlated to the blood EtOH levels. In the cyanamide-treated group, a peak and a plateau formed at the time corresponding to the second peak in the control group. The peak and plateau concentration of AcH increased markedly. We attempted simultaneous curve fitting, using the five blood EtOH and AcH concentration-time curves, to determine the pharmacokinetic model. Consequently, the AcH elimination was best described by a Michaelis-Menten kinetic model in both groups. Conclusions The blood AcH profile was suggested to consist of the first and second components that are related to the blood EtOH concentration itself and the metabolic formation of AcH, respectively. With higher EtOH doses or aldehyde dehydrogenase 2 inhibition, the second component becomes prominent as a result of the capacity-limited property of the metabolism of AcH, which is described by Michaelis-Menten elimination kinetics. [source] | |||||||||||||||||||