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Opposite
Kinds of Opposite Terms modified by Opposite Selected AbstractsMeadow Voles (Microtus pennsylvanicus) and Prairie Voles (M. ochrogaster) Differ in Their Responses to Over-Marks from Opposite- and Same-Sex ConspecificsETHOLOGY, Issue 11 2000Raymond L. Woodward Jr Over-marking occurs when one individual deposits its scent mark on the scent mark of a conspecific. Previous studies have shown that meadow voles (Microtus pennsylvanicus) and prairie voles (M. ochrogaster) that were exposed to an over-mark of two same-sex conspecifics, later responded similarly to the top-scent mark but differed in their response to the bottom-scent mark. In the present study, we examined the responses of meadow voles and prairie voles to same-sex and mixed-sex over-marks to ascertain whether their responses reflect the different tactics which males and females in promiscuous (meadow voles) and monogamous (prairie voles) species use to attract opposite-sex conspecifics and to compete with same-sex conspecifics. Males and females of both species spent more time investigating the mark of the top-scent donor than that of the bottom-scent donor of an over-mark. Meadow voles exposed to a mixed-sex over-mark spent more time investigating the mark of the opposite-sex conspecific independently of whether it was from the top- or bottom-scent donor. In contrast, prairie voles spent more time investigating the mark of the opposite-sex donor if it was from the top-scent donor. These results suggest that: (i) over-marking serves a competitive function; (ii) the scent marks of individuals attract multiple mates in promiscuous species such as the meadow vole; and (iii) the scent marks of individuals establish and maintain pair bonds between familiar opposite-sex conspecifics in monogamous species such as the prairie vole. [source] Revisiting a Classification Scheme for U.S.-Mexico Alluvial Basin-Fill AquifersGROUND WATER, Issue 5 2005Barry J. Hibbs Intermontane basins in the Trans-Pecos region of westernmost Texas and northern Chihuahua, Mexico, are target areas for disposal of interstate municipal sludge and have been identified as possible disposal sites for low-level radioactive waste. Understanding ground water movement within and between these basins is needed to assess potential contaminant fate and movement. Four associated basin aquifers are evaluated and classified; the Red Light Draw Aquifer, the Northwest Eagle Flat Aquifer, the Southeast Eagle Flat Aquifer, and the El Cuervo Aquifer. Encompassed on all but one side by mountains and local divides, the Red Light Draw Aquifer has the Rio Grande as an outlet for both surface drainage and ground water discharge. The river juxtaposed against its southern edge, the basin is classified as a topographically open, through-flowing basin. The Northwest Eagle Flat Aquifer is classified as a topographically closed and drained basin because surface drainage is to the interior of the basin and ground water discharge occurs by interbasin ground water flow. Mountains and ground water divides encompass this basin aquifer on all sides; yet, depth to ground water in the interior of the basin is commonly >500 feet. Negligible ground water discharge within the basin indicates that ground water discharges from the basin by vertical flow and underflow to a surrounding basin or basins. The most likely mode of discharge is by vertical, cross-formational flow to underlying Permian rocks that are more porous and permeable and subsequent flow along regional flowpaths beneath local ground water divides. The Southeast Eagle Flat Aquifer is classified as a topographically open and drained basin because surface drainage and ground water discharge are to the adjacent Wildhorse Flat area. Opposite the Eagle Flat and Red Light Draw aquifers is the El Cuervo Aquifer of northern Chihuahua, Mexico. The El Cuervo Aquifer has interior drainage to Laguna El Cuervo, which is a phreatic playa that also serves as a focal point of ground water discharge. Our evidence suggests that El Cuervo Aquifer may lose a smaller portion of its discharge by interbasin ground water flow to Indian Hot Springs, near the Rio Grande. Thus, El Cuervo Aquifer is a topographically closed basin that is either partially drained if a component of its ground water discharge reaches Indian Hot Springs or undrained if all its natural ground water discharge is to Laguna El Cuervo. [source] Numerical simulation of a single bubble by compressible two-phase fluidsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 6 2010Siegfried Müller Abstract The present work deals with the numerical investigation of a collapsing bubble in a liquid,gas fluid, which is modeled as a single compressible medium. The medium is characterized by the stiffened gas law using different material parameters for the two phases. For the discretization of the stiffened gas model, the approach of Saurel and Abgrall is employed where the flow equations, here the Euler equations, for the conserved quantities are approximated by a finite volume scheme, and an upwind discretization is used for the non-conservative transport equations of the pressure law coefficients. The original first-order discretization is extended to higher order applying second-order ENO reconstruction to the primitive variables. The derivation of the non-conservative upwind discretization for the phase indicator, here the gas fraction, is presented for arbitrary unstructured grids. The efficiency of the numerical scheme is significantly improved by employing local grid adaptation. For this purpose, multiscale-based grid adaptation is used in combination with a multilevel time stepping strategy to avoid small time steps for coarse cells. The resulting numerical scheme is then applied to the numerical investigation of the 2-D axisymmetric collapse of a gas bubble in a free flow field and near to a rigid wall. The numerical investigation predicts physical features such as bubble collapse, bubble splitting and the formation of a liquid jet that can be observed in experiments with laser-induced cavitation bubbles. Opposite to the experiments, the computations reveal insight to the state inside the bubble clearly indicating that these features are caused by the acceleration of the gas due to shock wave focusing and reflection as well as wave interaction processes. While incompressible models have been used to provide useful predictions on the change of the bubble shape of a collapsing bubble near a solid boundary, we wish to study the effects of shock wave emissions into the ambient liquid on the bubble collapse, a phenomenon that may not be captured using an incompressible fluid model. Copyright © 2009 John Wiley & Sons, Ltd. [source] Improved third-order Møller,Plesset perturbation theoryJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 13 2003Stefan Grimme Abstract Based on a partitioning of the total correlation energy into contributions from parallel- and antiparallel-spin pairs of electrons, a modified third-order Møller,Plesset (MP) perturbation theory is developed. The method, termed SCS,MP3 (SCS for spin-component-scaled) continues previous work on an improved version of MP2 (S. Grimme, J Chem Phys 2003, 118, 9095). A benchmark set of 32 isogyric reaction energies, 11 atomization energies, and 11 stretched geometries is used to assess to performance of the model in comparison to the standard quantum chemical approaches MP2, MP3, and QCISD(T). It is found, that the new method performs significantly better than usual MP2/MP3 and even outperforms the more costly QCISD method. Opposite to the usual MP series, the SCS third-order correction uniformly improves the results. Dramatic enhancements are especially observed for the more difficult atomization energies, some of the stretched geometries, and reaction and ionization energies involving transition metal compounds where the method seems to be competitive or even superior to the widely used density functional approaches. Further tests performed for other complex systems (biradicals, C20 isomers, transition states) demonstrate that the SCS,MP3 model yields often results of QCISD(T) accuracy. The uniformity with which the new approach improves for very different correlation problems indicates significant robustness, and suggests it as a valuable quantum chemical method of general use. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 1529,1537, 2003 [source] Caffeine inhibition of rat carotid body chemoreceptors is mediated by A2A and A2B adenosine receptorsJOURNAL OF NEUROCHEMISTRY, Issue 2 2006S. V. Conde Abstract Caffeine, an unspecific antagonist of adenosine receptors, is commonly used to treat the apnea of prematurity. We have defined the effects of caffeine on the carotid body (CB) chemoreceptors, the main peripheral controllers of breathing, and identified the adenosine receptors involved. Caffeine inhibited basal (IC50, 210 µm) and low intensity (PO2 , 66 mm Hg/30 mm K+) stimulation-induced release of catecholamines from chemoreceptor cells in intact preparations of rat CB in vitro. Opposite to caffeine, 5,-(N -ethylcarboxamido)adenosine (NECA; an A2 agonist) augmented basal and low-intensity hypoxia-induced release. 2- p -(2-Carboxyethyl)phenethyl-amino-5,- N -ethylcaboxamido-adenosine hydrochloride (CGS21680), 2-hexynyl-NECA (HE-NECA) and SCH58621 (A2A receptors agents) neither affected catecholamine release nor altered the caffeine effects. The 8-cycle-1,3-dipropylxanthine (DPCPX; an A1/A2B antagonist) and 8-(4-{[(4-cyanophenyl)carbamoylmethyl]-oxy}phenyl)-1,3-di(n-propyl)xanthine (MRS1754; an A2B antagonist) mimicking of caffeine indicated that caffeine effects are mediated by A2B receptors. Immunocytochemical A2B receptors were located in tyrosine hydroxylase positive chemoreceptor cells. Caffeine reduced by 52% the chemosensory discharges elicited by hypoxia in the carotid sinus nerve. Inhibition had two components with pharmacological analysis indicating that A2A and A2B receptors mediate, respectively, the low (17 × 10,9 m) and high (160 × 10,6 m) IC50 effects. It is concluded that endogenous adenosine, via presynaptic A2B and postsynaptic A2A receptors, can exert excitatory effects on the overall output of the rat CB chemoreceptors. [source] Short-term propagation of rainfall perturbations on terrestrial ecosystems in central CaliforniaAPPLIED VEGETATION SCIENCE, Issue 2 2010Mónica García Abstract Question: Does vegetation buffer or amplify rainfall perturbations, and is it possible to forecast rainfall using mesoscale climatic signals? Location: Central California (USA). Methods: The risk of dry or wet rainfall events was evaluated using conditional probabilities of rainfall depending on El Niño Southern Oscillation (ENSO) events. The propagation of rainfall perturbations on vegetation was calculated using cross-correlations between monthly seasonally adjusted (SA) normalized difference vegetation index (NDVI) from the Advanced Very High Resolution Radiometer (AVHRR), and SA antecedent rainfall at different time-scales. Results: In this region, El Niño events are associated with higher than normal winter precipitation (probability of 73%). Opposite but more predictable effects are found for La Niña events (89% probability of dry events). Chaparral and evergreen forests showed the longest persistence of rainfall effects (0-8 months). Grasslands and wetlands showed low persistence (0-2 months), with wetlands dominated by non-stationary patterns. Within the region, the NDVI spatial patterns associated with higher (lower) rainfall are homogeneous (heterogeneous), with the exception of evergreen forests. Conclusions: Knowledge of the time-scale of lagged effects of the non-seasonal component of rainfall on vegetation greenness, and the risk of winter rainfall anomalies lays the foundation for developing a forecasting model for vegetation greenness. Our results also suggest greater competitive advantage for perennial vegetation in response to potential rainfall increases in the region associated with climate change predictions, provided that the soil allows storing extra rainfall. [source] Study on the antinociceptive action of Tyr-K-MIF-1, a peptide from the MIF familyAUTONOMIC & AUTACOID PHARMACOLOGY, Issue 2 2007R. Zamfirova Summary 1 Tyr-K-MIF-1 is a melanocyte inhibiting factor (MIF) neuropeptide, isolated from the brain. Opposite to other MIFs (Tyr-MIF-1, Tyr-W-MIF-1), it has a very low affinity for opiate , -receptors, but interacts with Tyr-MIF-1 specific binding sites. Tyr-MIF-1 and Tyr-W-MIF-1 evoke antinociception mainly by activating opioid receptors. We investigated the possible antinociceptive effect of Tyr-K-MIF-1 and the involvement of histaminergic system in its mechanism of action. 2 Tested on rats by paw-pressure test, Tyr-K-MIF-1 (0.5, 1 and 2 mg kg,1) was associated with short-lasting analgesia, which was abolished by naloxone (1 mg kg,1). 3 Injected intraperitoneally (i.p.) 15 min before Tyr-K-MIF-1, antagonists of H1 (diphenhydramine, 100 mg kg,1) or H2 (famotidine, 0.3 and 0.6 mg kg,1) histamine receptors diminished peptide antinociceptive effect. Simultaneous H1 - and H2 blockade, as well as pretreatment with 5 mg kg,1 dimaprit (H2 agonist) abolished Tyr-K-MIF-1-induced analgesia. Tyr-K-MIF-1-induced analgesia was also abolished by treatment with R-(,)-methylhistamine (10 mg kg,1, i.p.), an H3 histamine receptor agonist that acts to inhibit histamine release. 4 Our results together with data reported in the literature support the conclusion that activation of the histaminergic system is involved in the mechanism of Tyr-K-MIF-1-induced antinociception. [source] Opposites attract: MHC-associated mate choice in a polygynous primateJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 1 2010J. M. SETCHELL Abstract We investigated reproduction in a semi-free-ranging population of a polygynous primate, the mandrill, in relation to genetic relatedness and male genetic characteristics, using neutral microsatellite and major histocompatibility complex (MHC) genotyping. We compared genetic dissimilarity to the mother and genetic characteristics of the sire with all other potential sires present at the conception of each offspring (193 offspring for microsatellite genetics, 180 for MHC). The probability that a given male sired increased as pedigree relatedness with the mother decreased, and overall genetic dissimilarity and MHC dissimilarity with the mother increased. Reproductive success also increased with male microsatellite heterozygosity and MHC diversity. These effects were apparent despite the strong influence of dominance rank on male reproductive success. The closed nature of our study population is comparable to human populations for which MHC-associated mate choice has been reported, suggesting that such mate choice may be especially important in relatively isolated populations with little migration to introduce genetic variation. [source] Size Selection During Crystallization of Oppositely Charged NanoparticlesCHEMISTRY - A EUROPEAN JOURNAL, Issue 9 2009Bartlomiej Kowalczyk Dr. Abstract Opposites attract (selectively): Oppositely charged nanoparticles characterized by different size distributions form 3D supracrystals (see figure) only if the distributions overlap. Crystal quality decreases rapidly with decreasing degree of overlap, and, irrespective of the ratio of particle diameters/charges, no crystals are observed for non-overlapping distributions. [source] A comparison of concurrent programming and cooperative multithreading under load balancing applicationsCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 4 2004Justin T. Maris Abstract Two models of thread execution are the general concurrent programming execution model (CP) and the cooperative multithreading execution model (CM). CP provides nondeterministic thread execution where context switches occur arbitrarily. CM provides threads that execute one at a time until they explicitly choose to yield the processor. This paper focuses on a classic application to reveal the advantages and disadvantages of load balancing during thread execution under CP and CM styles; results from a second classic application were similar. These applications are programmed in two different languages (SR and Dynamic C) on different hardware (standard PCs and embedded system controllers). An SR-like run-time system, DesCaRTeS, was developed to provide interprocess communication for the Dynamic C implementations. This paper compares load balancing and non-load balancing implementations; it also compares CP and CM style implementations. The results show that in cases of very high or very low workloads, load balancing slightly hindered performance; and in cases of moderate workload, both SR and Dynamic C implementations of load balancing generally performed well. Further, for these applications, CM style programs outperform CP style programs in some cases, but the opposite occurs in some other cases. This paper also discusses qualitative tradeoffs between CM style programming and CP style programming for these applications. Copyright © 2004 John Wiley & Sons, Ltd. [source] Homicide, psychopathology, prosecutorial and jury discretion and the death penaltyCRIMINAL BEHAVIOUR AND MENTAL HEALTH, Issue 4 2000Chief, Division of Forensic Psychiatry, Richard M. Yarvis MD MPH Professor of Clinical Psychiatry Introduction The American preoccupation with the death penalty persists and, in fact, shows no sign of abatement. This is demonstrated not only by attitudinal measures but also by the quickening pace of executions. In California, homicide convictions can result in either 25-year-to-life, life-with-no-possibility-of-parole, or death sentences. The ultimate outcome in any given case is determined by a complex interaction of prosecutorial and jury decisions. Three vignettes illustrate how heinous crimes have been handled quite variably. Method A data set comprising 115 homicide cases was examined. To determine how murderers who qualify for the death penalty differed, if at all, from those who did not so qualify, 52 defendants who met the criteria for a death sentence were compared with 63 who did not. Criteria utilized and ignored by prosecutors in seeking the death penalty were analysed by comparing 39 cases in which death sentences could have been and were sought with 13 cases in which prosecutors chose to seek a lesser penalty instead. Finally, criteria utilized and ignored by juries to reach sentencing decisions were analysed by comparing 25 cases in which juries chose not to hand down death sentences with 14 cases in which they did render death verdicts. Results Special circumstance murderers did not differ significantly on personal variables from ordinary murderers. (1) Special circumstances were invariably charged when more than one criterion for this was present. Robbery and sexual assault usually provoked a special circumstances charge. Mitigating factors did not deter prosecutors from charging a special circumstance. (2) There was no excess of aggravating factors in individuals sentenced to death by juries, indeed there was a trend for the opposite to be the case, but there was a trend for mitigating factors to be commoner in those excused the death penalty. Conclusion It is not clear that the death penalty process in California carries out the legislature's intent but the US Supreme Court's 1976 mandate that mitigating and aggravating factors should provide discretion may be having a modest impact. Copyright © 2000 Whurr Publishers Ltd. [source] The Animated Muse: An Interpretive Program for Creative ViewingCURATOR THE MUSEUM JOURNAL, Issue 3 2005Austin Clarkson ABSTRACT Explore a Painting in Depth, an experiment presented in the Canadian Collection of the Art Gallery of Ontario, consisted of a booth that offered seating for two visitors and, opposite them, The Beaver Dam, a 1919 landscape painting by the Canadian artist J. E. H. MacDonald. In a 12-minute audio-guided Exercise for Exploring, visitors were invited to engage in a creative process with the imagery of the painting. This paper sketches how the experiment evolved, presents the background of the Exercise for Exploring, and surveys the effects of the exhibit on a wide range of visitors. The question is raised: How can facilitating visitors' creative responses to artworks be part of the museum's educational mandate and its arsenal of interpretive resources? More broadly: Do strategies that foster and privilege visitor creativity, as well as honor the creativity of artists, affect the accessibility and relevance of the museum for the general public? [source] Incorrect citation suggests an opinion opposite to our conviction: a clarificationDENTAL TRAUMATOLOGY, Issue 3 2009Yango Pohl No abstract is available for this article. [source] Epigenetic control of translation regulation: Alterations in histone H3 lysine 9 post-translation modifications are correlated with the expression of the translation initiation factor 2B (Eif2b5) during thermal control establishmentDEVELOPMENTAL NEUROBIOLOGY, Issue 2 2010Tatiana Kisliouk Abstract Thermal control set point is regulated by thermosensitive neurons of the preoptic anterior hypothalamus (PO/AH) and completes its development during postnatal critical sensory period. External stimuli, like increase in environmental temperature, influence the neuronal protein repertoire and, ultimately, cell properties via activation or silencing of gene transcription, both of which are regulated by the "histone code."" Here, we demonstrated an increase in global histone H3 lysine 9 (H3K9) acetylation as well as H3K9 dimethylation in chick PO/AH during heat conditioning at the critical period of sensory development. In contrast to the global profile of H3K9 modifications, acetylation and dimethylation patterns of H3K9 at the promoter of the catalytic subunit of eukaryotic translation initiation factor 2B (Eif2b5) were opposite to each other. During heat conditioning, there was an increase in H3K9 acetylation at the Eif2b5 promoter, simultaneously with decrease in H3K9 dimethylation. These alterations coincided with Eif2b5 mRNA induction. Moreover, exposure to excessive heat during the critical period resulted in long-term effect on both H3K9 tagging at the Eif2b5 promoter and Eif2b5 mRNA expression. These data suggest a role for dynamic H3K9 post-translational modifications in global translation regulation during the thermal control establishment. © 2009 Wiley Periodicals, Inc. Develop Neurobiol, 2010 [source] Islet transplantation: where do we stand now?,DIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 3 2003Boaz Hirshberg Abstract After many years of limited success in islet transplantation, researchers developing this procedure have made great strides, and several centers have now reported that islet transplantation can result in long-term insulin independence for patients with type 1 diabetes mellitus. The improved quality of life achieved in some islet allograft recipients suggests that this important line of investigation should proceed. Yet, several factors limit the technique and these hurdles must be overcome before it can be considered a practical treatment for the millions of individuals with diabetes, be it type 1 or type 2. Most obvious is the gross disparity between the number of islets available for clinical transplantation and the number of patients with diabetes who might benefit. Other important limitations, too often lost in the discussion, include complications associated with the technique itself, the toxicity of currently available immunosuppressive drugs, and the imperfect glycemia control achieved in most patients. In fact, our ongoing analysis as to whether transplantation-based therapy improves survival for patients with type 1 diabetes suggests that, for many at least, the opposite may be true. Two variables, as yet undefined, also need to be considered: (1) can the procedure, when done well, prevent or reverse diabetes-associated complications and (2) what are the long-term consequences of intrahepatic islets? Published in 2003 by John Wiley & Sons, Ltd. [source] Idols and Demons: On Discerning the SpiritsDIALOG, Issue 1 2002Vitor Westhelle This article elaborates on the distinction between two spiritual ailments, which can be properly identified as idolatry and demonry. They represent opposite but complementary age,long phenomena still relevant to the analysis of the contemporary spiritual situation in explaining disorders of the soul as well as cultural derangement. The text suggests that the church as the spiritual community is the locus for the discernment of the spirit and that in its two distinguishing foundational and functional features (the proclamatory function and the communion function) it is molded precisely to confront both idols and demons. [source] Identification of some human genes oppositely regulated during esophageal squamous cell carcinoma formation and human embryonic esophagus developmentDISEASES OF THE ESOPHAGUS, Issue 3 2010M. V. Zinovyeva SUMMARY Here we directly compared gene expression profiles in human esophageal squamous cell carcinomas and in human fetal esophagus development. We used the suppression subtractive hybridization technique to subtract cDNAs prepared from tumor and normal human esophageal samples. cDNA sequencing and reverse transcription polymerase chain reaction (RT-PCR) analysis of RNAs from human tumor and the normal esophagus revealed 10 differentially transcribed genes: CSTA, CRNN, CEACAM1, MAL, EMP1, ECRG2, and SPRR downregulated, and PLAUR, SFRP4, and secreted protein that is acidic and rich in cysteine upregulated in tumor tissue as compared with surrounding normal tissue. In turn, genes up- and downregulated in tumor tissue were down- and upregulated, respectively, during development from the fetal to adult esophagus. Thus, we demonstrated that, as reported for other tumors, gene transcriptional activation and/or suppression events in esophageal tumor progression were opposite to those observed during development from the fetal to adult esophagus. This tumor ,embryonization' supports the idea that stem or progenitor cells are implicated in esophageal cancer emergence. [source] Reservoir siltation in the semi-arid highlands of northern Ethiopia: sediment yield,catchment area relationship and a semi-quantitative approach for predicting sediment yieldEARTH SURFACE PROCESSES AND LANDFORMS, Issue 11 2006L. Tamene Abstract Due to shortage of rainfall and its increasing variability, moisture stress is identified to be one of the most critical factors affecting agricultural productivity in the drylands of Ethiopia. To circumvent this problem, a strategy of supplemental irrigation through surface water harvesting was adopted by the government and several micro-dams have been built in the semi-arid parts of the country. However, the benefits from the water harvesting schemes are not sustainable because of rapid water storage loss due to siltation. There is, therefore, an urgent need for improved catchment-based erosion control and sediment management strategies. The design and implementation of such strategies require data on the rate and magnitude of sediment deposition. To this end, reservoir surveys were conducted to estimate sediment deposition rate for 11 reservoirs identified to be representative of catchments in the Tigray region of northern Ethiopia. Two approaches were employed during the survey: one was based on measurement of sediment thickness in reservoirs while the other was based on comparing the original and existing topography of the reservoir-beds. The average annual sediment yield estimated for the study sites was about 19 t ha,1 y,1. An equation of the type SSY = 3á36A0á67 (with SSY = area specific sediment yield in t ha,1 y,1 and A = catchment area in km2) was also established for the study region, which is opposite to the ,universal' SSY,A relationship. In order to improve the sediment yield predictive capability of A, it was integrated with a factorial index that assesses the catchment's propensity to erosion and potential sediment yield. The effect of accelerated sediment deposition on water storage loss of reservoirs and possible controlling factors of the SSY,A relationship are outlined. The potential semi-quantitative scoring approach to characterize catchments in terms of erosion sensitivity and the significance of the A -index approach to predict SSY of similar catchments are also highlighted. Copyright © 2006 John Wiley & Sons, Ltd. [source] Seismic demand sensitivity of reinforced concrete shear-wall building using FOSM methodEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 14 2005Tae-Hyung Lee Abstract The uncertainty in the seismic demand of a structure (referred to as the engineering demand parameter, EDP) needs to be properly characterized in performance-based earthquake engineering. Uncertainties in the ground motion and in structural properties are responsible for EDP uncertainty. In this study, sensitivity of EDPs to major uncertain variables is investigated using the first-order second-moment method for a case study building. This method is shown to be simple and efficient for estimating the sensitivity of seismic demand. The EDP uncertainty induced by each uncertain variable is used to determine which variables are most significant. Results show that the uncertainties in ground motion are more significant for global EDPs, namely peak roof acceleration and displacement, and maximum inter-storey drift ratio, than those in structural properties. Uncertainty in the intensity measure (IM) of ground motion is the dominant variable for uncertainties in local EDPs such as the curvature demand at critical cross-sections. Conditional sensitivity of global and local EDPs given IM is also estimated. It is observed that the combined effect of uncertainties in structural properties is more significant than uncertainty in ground motion profile at lower IM levels, while the opposite is true at higher IM levels. Copyright © 2005 John Wiley & Sons, Ltd. [source] A Nomogram for Measurement of Mitral Valve Area by Proximal Isovelocity Surface Area MethodECHOCARDIOGRAPHY, Issue 8 2007Mehmet Uzun M.D. Introduction: Although its accuracy has been documented in many studies, the proximal isovelocity surface area (PISA) method is not used widely for mitral valve area (MVA) measurement. In this study, we prepared a new nomogram and tested its use in MVA assessment. Material and Methods: The study included 23 patients (age: 27 ± 5 years) with mitral stenosis, of whom 7 were in atrial fibrillation. The MVA was measured by four methods: planimetry (PL) (reference method), pressure-half time (PHT), conventional PISA (CP), and nomogram (Nomo) methods. The nomogram included two unknowns: (1) r; the radius of the first PISA section; (2) a; the length of the border opposite to the PISA angle in the triangle with both adjacent borders of 1 cm. The nomogram was also tested for its popularity potential by eight echocardiographers, none of whom were included in the author list. Results: Mean MVAPL was 1.85 ± 0.53 cm2 (range: 0.72,2.99), mean MVAPHT was 1.72 ± 0.56 cm2 (range: 0.91,3.30), mean MVACP was 1.69 ± 0.45 cm2 (range: 0.97,2.54), and MVANomo was 1.70 ± 0.44 cm2 (0.96,2.49). The nomogram correlated with planimetry (r = 0.87; P < 0.001), pressure half-time (r = 0.71; P < 0.001) and conventional PISA (r = 0.99; P = 0.000) methods. The nomogram method also correlated with planimetry in patients with atrial fibrillation (r = 0.81; P = 0.026). The echocardiographers found that the nomogram is superior to the planimetry and conventional PISA methods but inferior to the pressure half-time method in terms of simplicity. Conclusion: The new nomogram is potentially helpful in measurement of MVA. It may be used as an additional method in assessing severity of mitral stenosis. [source] Contrasting spatial and temporal global change impacts on butterfly species richness during the 20th centuryECOGRAPHY, Issue 6 2006Peter White Regional patterns of species richness are often explained by models using temperature or measures habitat suitability. Generally, species richness is positively associated with temperature, and negatively associated with habitat degradation. While these models have been well tested across spatial scales, they have rarely been tested on a temporal scale , in part due to the difficulty in ascertaining accurate historical data at an appropriate resolution. In this study, we compared the results of temporal and spatial models, each incorporating two predictors of species richness: temperature, and human population density (as a surrogate of human-related habitat impacts). We found that the change in species richness from the early to late part of the 20th century was positively correlated with temperature change, and negatively correlated with human population density change. When we compared these results to two spatial models using contemporary and historic data, the spatial effects of temperature on butterfly richness were similar to its temporal effects, while the effect of human population density through time is the opposite of its spatial effect. More generally, the assumption that spatial patterns are equivalent to temporal ones when applying macroecological data to global change is clearly unreliable. [source] Non-native species disrupt the worldwide patterns of freshwater fish body size: implications for Bergmann's ruleECOLOGY LETTERS, Issue 4 2010Simon Blanchet Ecology Letters (2010) 13: 421,431 Abstract In this study, we test whether established non-native species induce functional changes in natural assemblages. We combined data on the body size of freshwater fish species and a worldwide data set of native and non-native fish species for 1058 river basins. We show that non-native fish species are significantly larger than their native counterparts and are a non-random subset of the worldwide set of fish species. We further show that the median body size of fish assemblages increases in the course of introductions. These changes are the opposite of those expected under several null models. Introductions shift body size patterns related to several abiotic factors (e.g. glacier coverage and temperature) in a way that modifies latitudinal patterns (i.e. Bergmann's rule), especially in the southern hemisphere. Together, these results show that over just the last two centuries human beings have induced changes in the global biogeography of freshwater fish body size, which could affect ecosystem properties. [source] Mass invariance of population nitrogen flux by terrestrial mammalian herbivores: an extension of the energetic equivalence ruleECOLOGY LETTERS, Issue 9 2008Christopher W. Habeck Abstract According to the energetic equivalence rule, energy use by a population is independent of average adult body mass. Energy use can be equated with carbon flux, and it has been suggested that population fluxes of other materials, such as nitrogen and phosphorus, might also be independent of body mass. We compiled data on individual nitrogen deposition rates (via faeces and urine) and average population densities of 26 species of mammalian herbivores to test the hypothesis of elemental equivalence for nitrogen. We found that the mass scaling of individual nitrogen flux was opposite to that of population density for the species in our dataset. By computing the product of individual nitrogen flux and average population density for each species in our dataset, we found that population-level nitrogen flux was independent of species mass, averaging c. 3.22 g N ha,1 day,1. Results from this analysis can be used to understand the influence of mammalian herbivore communities on nitrogen cycling in terrestrial ecosystems. [source] Complexity can enhance stability in competitive systemsECOLOGY LETTERS, Issue 5 2001Ian D. Rozdilsky Empirical observations often indicate that complexity enhances stability, while most theoretical studies, such as May's (1972) classic paper, point to the opposite. Despite the wide generality of these latter theoretical analyses, our examination of the well-known competitive Lotka,Volterra system reveals that increasing complexity (measured in terms of connectance) can enhance species coexistence and persistence in model communities (measured in terms of their feasibility and stability). The high feasibility and stability found for tightly interconnected competitive subsystems might provide an explanation for the clumped structure in food webs. [source] What Happens When Wal-Mart Comes to Town: An Empirical Analysis of the Discount Retailing IndustryECONOMETRICA, Issue 6 2008Panle Jia In the past few decades multistore retailers, especially those with 100 or more stores, have experienced substantial growth. At the same time, there is widely reported public outcry over the impact of these chain stores on other retailers and local communities. This paper develops an empirical model to assess the impact of chain stores on other discount retailers and to quantify the size of the scale economies within a chain. The model has two key features. First, it allows for flexible competition patterns among all players. Second, for chains, it incorporates the scale economies that arise from operating multiple stores in nearby regions. In doing so, the model relaxes the commonly used assumption that entry in different markets is independent. The lattice theory is exploited to solve this complicated entry game among chains and other discount retailers in a large number of markets. It is found that the negative impact of Kmart's presence on Wal-Mart's profit was much stronger in 1988 than in 1997, while the opposite is true for the effect of Wal-Mart's presence on Kmart's profit. Having a chain store in a market makes roughly 50% of the discount stores unprofitable. Wal-Mart's expansion from the late 1980s to the late 1990s explains about 40,50% of the net change in the number of small discount stores and 30,40% for all other discount stores. Scale economies were important for Wal-Mart, but less so for Kmart, and the magnitude did not grow proportionately with the chains' sizes. [source] The international monetary system in the last and next 20 yearsECONOMIC POLICY, Issue 47 2006Barry Eichengreen SUMMARY The evolution of exchange rate regimes The last two decades have seen far-reaching changes in the structure of the international monetary system. Europe moved from the European Monetary System to the euro. China adopted a dollar peg and then moved to a basket, band and crawl in 2005. Emerging markets passed through a series of crises, leading some to adopt regimes of greater exchange rate flexibility and others to rethink the pace of capital account liberalization. Interpreting these developments is no easy task: some observers conclude that recent trends are confirmation of the ,bipolar view' that intermediate exchange rate arrangements are disappearing, while members of the ,fear of floating school' conclude precisely the opposite. We show that the two views can be reconciled if one distinguishes countries by their stage of economic and financial development. Among the advanced countries, intermediate regimes have essentially disappeared; this supports the bipolar view for the group of countries for which it was first developed. Within this subgroup, the dominant movement has been toward hard pegs, reflecting monetary unification in Europe. While emerging markets have also seen a decline in the prevalence of intermediate arrangements, these regimes still account for more than a third of the relevant subsample. Here the majority of the evacuees have moved to floats rather than fixes, reflecting the absence of EMU-like arrangements in other parts of the world. Among developing countries, the prevalence of intermediate regimes has again declined, but less dramatically. Where these regimes accounted for two-thirds of the developing country subsample in 1990, they account for a bit more than half of that subsample today. As with emerging markets, the majority of those abandoning the middle have moved to floats rather than hard pegs. The gradual nature of these trends does not suggest that intermediate regimes will disappear outside the advanced countries anytime soon. , Barry Eichengreen and Raul Razo-Garcia [source] Novel negatively charged tentacle-type polymer coating for on-line preconcentration of proteins in CEELECTROPHORESIS, Issue 4 2009Liang Xu Abstract A novel negatively charged tentacle-type polymer-coated capillary column was fabricated and applied for on-line extraction and preconcentration of proteins. The polymer coating was prepared by glycidyl-methacrylate graft polymerization in a silanized capillary column and the following sulfonic acid group functionalization. It had high surface area and offered high phase ratio for protein adsorption. In addition, the polymer-coated capillary column provided more stable EOF than a bare uncoated capillary. These features of the polymer coating facilitated the extraction of proteins through electrostatic interactions. This was used to extract proteins. The extracted analytes were then desorbed and focused by EOF in the direction opposite to the sample injection flow for subsequent CE. With this procedure, over 1500-fold sensitivity enhancement was realized for myoglobin (MB) as compared with a normal capillary zone electrophoresis. By comparison of the peak areas of the enriched protein, it was found that the polymer-coated column could capture proteins about 30 times more than the uncoated column. In addition, the separation of a protein mixture containing 0.4,,g/mL of MB and 0.4,,g/mL of insulin was demonstrated by the on-line preconcentration and electrophoretic separation with the polymer-coated column. [source] A model for targeted substitution mutagenesis during SOS replication of double-stranded DNA containing cis-syn cyclobutane thymine dimersENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 9 2006Helen A. Grebneva Abstract A model for ultraviolet mutagenesis is described that is based on the formation of rare tautomeric bases in pyrimidine dimers. It is shown that during SOS synthesis the modified DNA-polymerase inserts canonical bases opposite the dimers; the inserted bases are capable of forming hydrogen bonds with bases in the template DNA. SOS-replication of double-stranded DNA having thymine dimers, with one or both bases in a rare tautomeric conformation, results in targeted transitions, transversions, or one-nucleotide gaps. Structural analysis indicates that one type of dimer containing a single tautomeric base (TT1*, with the "*" indicating a rare tautomeric base and the subscript referring to the particular conformation) can cause A:T , G:C transition or homologous A:T , T:A transversion, while another dimer (TT2*) can cause a one-nucleotide gap. The dimers containing T4* result in A:T , C:G transversion, while TT5* dimers can cause A:T , C:G transversion or homologous A:T , T:A transversion. If both bases in the dimer are in a rare tautomeric form, then tandem mutations or double-nucleotide gaps can be formed. The dimers containing the rare tautomeric forms T1 *,, T2*,, T3*,, T4*,, and T5*, may not result in mutations. The question of whether dimers containing T4*, and T5*, result in mutations requires further investigation. Environ. Mol. Mutagen., 2006. © 2006 Wiley-Liss, Inc. [source] At the birth of molecular radiation biology ,ENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 2-3 2001Raymond Devoret Abstract Rational thinking builds on feelings, too. This article starts with a tribute to Richard Setlow, an eminent scientist; it retraces as well some studies in molecular genetics that helped to understand basic questions of radiation biology. In the mid-1950s, the induction of a dormant virus (prophage) by irradiation of its host was an intriguing phenomenon. Soon, it was found that prophage induction results from the inactivation of the prophage repressor. Similarly, a score of induced cellular SOS functions were found to be induced when the LexA repressor is inactivated. Repressor inactivation involves the formation of a newly formed distinctive structure: a RecA-polymer wrapped around single-stranded DNA left by the arrest of replication at damaged sites. By touching this RecA nucleofilament, the LexA repressor is inactivated, triggering the sequential expression of SOS functions. The RecA nucleofilament acts as a chaperone, allowing recombinational repair to occur after nucleotide excision repair is over. The UmuD,C complex, synthesized slowly and parsimoniously, peaks at the end of recombinational repair, ready to be positioned at the tip of a RecA nucleofilament, placing the UmuD,C complex right at a lesion. At this location, UmuD,C prevents recombinational repair, and now acts as an error-prone paucimerase that fills the discontinuity opposite the damaged DNA. Finally, the elimination of lesions from the path of DNA polymerase, allows the resumption of DNA replication, and the SOS repair cycle switches to a normal cell cycle. Environ. Mol. Mutagen. 38:135,143, 2001. © 2001 Wiley-Liss, Inc. [source] Substrate incorporation patterns of bacterioplankton populations in stratified and mixed waters of a humic lakeENVIRONMENTAL MICROBIOLOGY, Issue 7 2009Ulrike Buck Summary Bacterial incorporation of glucose, leucine, acetate and 4-hydroxybenzoic acid (HBA) was investigated in an artificially divided humic lake (Grosse Fuchskuhle, Germany). Two basins with contrasting influx of allochthonous organic carbon were sampled during late summer stratification (oxic and anoxic layers) and after autumn mixing. High total and cell-specific incorporation rates were observed for glucose and HBA in stratified and mixed waters respectively, but only a small fraction of bacteria visibly incorporated HBA. The oxic layer of the more humic-rich basin featured a significantly lower fraction of glucose incorporating cells and substantially higher proportions of acetate assimilating bacteria. Niche differentiation was observed in two betaproteobacterial populations: cells affiliated with the Polynucleobacter C subcluster efficiently incorporated acetate but little glucose, whereas the opposite was found for members of the R-BT065 clade. By contrast, leucine incorporation was variable in both taxa. Considering the high concentrations and rapid photochemical generation of organic acids in humic waters our results may help to explain the success of the Polynucleobacter C lineage in such habitats. Specific substrate or habitat preferences were also present in three subgroups of the actinobacterial acI lineage: The numerically dominant clade in oxic waters (acI-840-1) was absent in the anoxic zone and did not incorporate acetate. A second group (acI-840-2) was found both in the epi- and hypolimnion, whereas the third one (acI-840-3) only occurred in anoxic waters. Altogether our results suggest a constitutive preference for some substrates versus an adaptive utilization of others in the studied microbial groups. [source] | ||||||||||||||||||||||||||||||||||||||||||||||||||||