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Selected AbstractsThe influence of pool length on local turbulence production and energy slope: a flume experimentEARTH SURFACE PROCESSES AND LANDFORMS, Issue 11 2004Douglas M. Thompson Abstract The in,uence of pool length on the strength of turbulence generated by vortex shedding was investigated in a 6 m long recirculating ,ume. The experiment utilized a 38% constriction of ,ow and an average channel-bed slope of 0·007. The base geometry for the intermediate-length pool experiment originated from a highly simpli,ed, 0·10 scale model of a forced pool from North Saint Vrain Creek, Colorado. Discharge in the ,ume was 31·6 l/s, which corresponds to a discharge in the prototype channel of 10 m3/s. Three shorter and four longer pool lengths also were created with a ,xed bed to determine changes in turbulence intensities and energy slope with pool elongation. Three-dimensional velocities were measured with an acoustic Doppler velocimeter at 31,40 different 0·6-depth and near-bed locations downstream of the rectangular constriction. The average velocity and root mean square (RMS) of the absolute magnitude of velocity at both depths are signi,cantly related to the distance from the constriction in most pool locations downstream of the constriction. In many locations, pool elongation results in a non-linear change in turbulence intensities and average velocity. Based on the overall ,ow pattern, the strongest turbulence occurs in the center of the pool along the shear zone between the jet and recirculating eddy. The lateral location of this shear zone is sensitive to changes in pool length. Energy slope also was sensitive to pool length due to a combination of greater length of the pool and greater head loss with shorter pools. The results indicate some form of hydraulic optimization is possible with pools adjusting their length to adjust the location and strength of turbulent intensities in the center of pools, and lower their rate of energy dissipation. Copyright © 2004 John Wiley & Sons, Ltd. [source] Indication of antagonistic interaction between climate change and erosion on plant species richness and soil properties in semiarid Mediterranean ecosystemsGLOBAL CHANGE BIOLOGY, Issue 2 2009PATRICIO GARCÍA-FAYOS Abstract We analyzed the consequences of climate change and the increase in soil erosion, as well as their interaction on plant and soil properties in semiarid Mediterranean shrublands in Eastern Spain. Current models on drivers of biodiversity change predict an additive or synergistic interaction between drivers that will increase the negative effects of each one. We used a climatic gradient that reproduces the predicted climate changes in temperature and precipitation for the next 40 years of the wettest and coldest end of the gradient; we also compared flat areas with 20° steep hillslopes. We found that plant species richness and plant cover are negatively affected by climate change and soil erosion, which in turn negatively affects soil resistance to erosion, nutrient content and water holding capacity. We also found that plant species diversity correlates weakly with plant cover but strongly with soil properties related to fertility, water holding capacity and resistance to erosion. Conversely, these soil properties correlate weaker with plant species cover. The joint effect of climate change and soil erosion on plant species richness and soil characteristics is antagonistic. That is, the absolute magnitude of change is smaller than the sum of both effects. However, there is no interaction between climate change and soil erosion on plant cover and their effects fit the additive model. The differences in the interaction model between plant cover and species richness supports the view that several soil properties are more linked to the effect that particular plant species have on soil processes than to the quantity and quality of the plant cover and biomass they support. Our findings suggest that plant species richness is a better indicator than plant cover of ecosystems services related with soil development and protection to erosion in semiarid Mediterranean climates. [source] The regional variation of aboveground live biomass in old-growth Amazonian forestsGLOBAL CHANGE BIOLOGY, Issue 7 2006YADVINDER MALHI Abstract The biomass of tropical forests plays an important role in the global carbon cycle, both as a dynamic reservoir of carbon, and as a source of carbon dioxide to the atmosphere in areas undergoing deforestation. However, the absolute magnitude and environmental determinants of tropical forest biomass are still poorly understood. Here, we present a new synthesis and interpolation of the basal area and aboveground live biomass of old-growth lowland tropical forests across South America, based on data from 227 forest plots, many previously unpublished. Forest biomass was analyzed in terms of two uncorrelated factors: basal area and mean wood density. Basal area is strongly affected by local landscape factors, but is relatively invariant at regional scale in moist tropical forests, and declines significantly at the dry periphery of the forest zone. Mean wood density is inversely correlated with forest dynamics, being lower in the dynamic forests of western Amazonia and high in the slow-growing forests of eastern Amazonia. The combination of these two factors results in biomass being highest in the moderately seasonal, slow growing forests of central Amazonia and the Guyanas (up to 350 Mg dry weight ha,1) and declining to 200,250 Mg dry weight ha,1 at the western, southern and eastern margins. Overall, we estimate the total aboveground live biomass of intact Amazonian rainforests (area 5.76 × 106 km2 in 2000) to be 93±23 Pg C, taking into account lianas and small trees. Including dead biomass and belowground biomass would increase this value by approximately 10% and 21%, respectively, but the spatial variation of these additional terms still needs to be quantified. [source] Zolpidem and triazolam interact differentially with a delay interval on a digit-enter-and-recall taskHUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 2 2001Craig R. Rush Abstract Zolpidem (AMBIEN®), an imidazopyridine, is now the most commonly prescribed hypnotic in the United States. Zolpidem is neuropharmacologically distinct from benzodiazepine hypnotics in that it binds with low affinity to ,5 -containing GABAA -receptor subtypes. Despite its unique benzodiazepine-receptor binding profile, the results of most of the published studies conducted with humans suggest that the absolute magnitude of impairment produced by zolpidem is comparable to that observed with benzodiazepine hypnotics like triazolam. The present study compared the acute effects of zolpidem (0, 7.5, 15 and 22.5,mg) and triazolam (0, 0.1875, 0.375 and 0.5625,mg) in 10 non-drug-abusing humans using a Digit-Enter-and-Recall task with varying delay intervals (0, 10 and 20,s). To more fully characterize the behavioral effects of zolpidem and triazolam, several other performance tasks and subject-rated drug-effect questionnaires were included. Zolpidem and triazolam impaired performance on the Digit-Enter-and-Recall task as a function of dose under all delay intervals. However, the dose-related effects of the drugs interacted differentially with the delay interval such that zolpidem produced significantly less impairment than triazolam following the longest delay (i.e., 20,s). Zolpidem and triazolam produced comparable dose-related impairment on the digit symbol substitution test (DSST), circular lights task, and picture recall/recognition task. Zolpidem and triazolam generally produced qualitatively and quantitatively similar subject-rated drug effects, although some between-drug differences were observed. Consistent with the pharmacokinetics of these drugs, the effects of zolpidem peaked sooner and were shorter in duration than those observed with triazolam. The results of this experiment suggest that zolpidem may have less potential than triazolam to impair recall, which may be due to differences between these compounds in terms of their benzodiazepine-receptor binding profile. The results of the present study are also concordant with previous studies that found that drugs that act at the GABAA -receptor complex can be differentiated based on their interaction with the delay interval on a Digit-Enter-and-Recall task. Copyright © 2001 John Wiley & Sons, Ltd. [source] Rapid determination of stress factors and absolute residual stresses in thin filmsJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 6 2006E. Eiper A methodology is presented that allows the determination of experimental stress factors in thin films on the basis of static diffraction measurements. The approach relies on the characterization of thin films deposited on a monocrystalline substrate serving as a mechanical sensor. Rocking-curve measurements of the symmetrical reflections of the substrate are used to determine the substrate curvature and subsequently the macroscopic stress imposed on the film. The elastic strain in the film is determined by lattice-spacing measurement at different sample tilt angles. The calculated experimental stress factors are applied to thin films deposited on other types of substrates and are used to determine the absolute magnitude of the residual stress. The approach is applied to nanocrystalline TiN and CrN thin films deposited on Si(100) and steel substrates, characterized using a laboratory-type ,/, goniometer. [source] Factors Associated with Differences in the Magnitude of Abnormal Returns Around NYSE Versus Nasdaq Firms' Earnings AnnouncementsJOURNAL OF BUSINESS FINANCE & ACCOUNTING, Issue 9-10 2001Youngsoon Susan Cheon This study provides an explanation for the ,exchange effect' puzzle documented in prior accounting research. Grant (1980) finds that the magnitude of earnings announcement week abnormal returns is higher, on average, for firms traded over-the-counter than for NYSE firms. Atiase (1987) shows that this incremental ,exchange effect' persists even after controlling for firm size. We investigate potential explanations for this incremental exchange effect. We first show that even after controlling for differences in firm size, Nasdaq firms have less rich information environments and enjoy greater growth opportunities than NYSE firms. We then investigate whether differential predisclosure information environments and/or growth opportunities can explain the incremental exchange effect. The results indicate that although the absolute magnitude of the earnings announcement-related abnormal returns is inversely related to proxies for the amount of predisclosure information, the incremental exchange effect cannot be explained by differences in the predisclosure information environment. In contrast, after controlling for differences in growth opportunities across NYSE versus Nasdaq firms, and investors' heightened sensitivity to Nasdaq firms' growth opportunities in particular, there is no significant incremental exchange effect (whether or not we control for predisclosure information). These results suggest that the incremental exchange effect puzzle documented in prior research is more likely to reflect growth-related phenomena than differences in the predisclosure information environment. [source] Multilevel Anthropogenic Cycles of Copper and Zinc: A Comparative Statistical AnalysisJOURNAL OF INDUSTRIAL ECOLOGY, Issue 1-2 2006Barbara Reck Contemporary cycles for copper and zinc are coanalyzed with the tools of exploratory data analysis. One-year analyses (circa 1994) are performed at three discrete spatial levels-country (52 countries that comprise essentially all anthropogenic stocks and flows of the two metals), eight world regions, and the planet as a whole-and are completed both in absolute magnitude and in per capita terms. This work constitutes, to our knowledge, the first multiscale, multilevel analysis of anthropogenic resources throughout their life cycles. The results demonstrate that (1) A high degree of correlation exists between country-level copper and country-level zinc rates of fabrication and manufacturing, entry into use, net addition to in-use stocks, discard, and landfilling; (2) Regional-level rates for copper and zinc cycle parameters show the same correlations as exist at country level; (3) On a per capita basis, countries add to in-use stock almost 50% more copper than zinc; (4) The predominant discard streams for copper and zinc at the global level are different for the two metals, and relative rates of different loss processes differ geographically, so that resource recovery policies must be designed from metalspecific and location-specific perspectives; (5)When absolute magnitudes of life-cycle flows are considered, the standard deviations of the data sets decrease from country level to regional level for both copper and zinc, which is not the case for the per capita data sets, where the statistical properties of the dat sets for both metals approach being independent of spatial level, thus providing a basis for predicting unmeasured per capita metal flow behavior. [source] Changes in explicit memory associated with early dementia in adults with Down's syndromeJOURNAL OF INTELLECTUAL DISABILITY RESEARCH, Issue 3 2002S. J. Krinsky-McHale Abstract Background A modified version of the Selective Reminding Test (SRT) (Buschke 1973) was used to examine the changes in memory that occur with early-stage dementia of the Alzheimer's type (DAT) in adults with intellectual disability (ID) and Down's syndrome (DS), and to compare these changes to those occurring with ,normal' ageing. Method Hierarchical linear modelling analyses showed steep declines in the performance of participants who had met the criteria for the onset of DAT. Non-demented participants also showed declines in performance which were related to their age. However, the absolute magnitude of these declines was consistent with a ,normal' ageing pattern and not with undetected dementia. Results In analysing the specific memory components that are compromised, the present authors found that participants with early-stage DAT showed severely diminished long-term storage and retrieval processing abilities compared to their non-demented peers. Notably, these declines preceded other symptoms of dementia, in most cases by more than a full year and sometimes by as much as 3 years. Conclusions Thus, the present results clearly confirm that memory processes are affected during early dementia in adults with DS, and that the SRT has promise as a clinical tool. [source] GHASP: an H, kinematic survey of spiral and irregular galaxies , V. Dark matter distribution in 36 nearby spiral galaxiesMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2008M. Spano ABSTRACT The results obtained from a study of the mass distribution of 36 spiral galaxies are presented. The galaxies were observed using Fabry,Perot interferometry as part of the GHASP survey. The main aim of obtaining high-resolution H, 2D velocity fields is to define more accurately the rising part of the rotation curves which should allow to better constrain the parameters of the mass distribution. The H, velocities were combined with low resolution H i data from the literature, when available. Combining the kinematical data with photometric data, mass models were derived from these rotation curves using two different functional forms for the halo: an isothermal sphere (ISO) and a Navarro,Frenk,White (NFW) profile. For the galaxies already modelled by other authors, the results tend to agree. Our results point at the existence of a constant density core in the centre of the dark matter haloes rather than a cuspy core, whatever the type of the galaxy from Sab to Im. This extends to all types the result already obtained by other authors studying dwarf and low surface brightness galaxies but would necessitate a larger sample of galaxies to conclude more strongly. Whatever model is used (ISO or NFW), small core radius haloes have higher central densities, again for all morphological types. We confirm different halo scaling laws, such as the correlations between the core radius and the central density of the halo with the absolute magnitude of a galaxy: low-luminosity galaxies have small core radius and high central density. We find that the product of the central density with the core radius of the dark matter halo is nearly constant, whatever the model and whatever the absolute magnitude of the galaxy. This suggests that the halo surface density is independent from the galaxy type. [source] Are galaxies with active galactic nuclei a transition population?MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2007P. B. Westoby ABSTRACT We present the results of an analysis of a well-selected sample of galaxies with active and inactive galactic nuclei from the Sloan Digital Sky Survey, in the range 0.01 < z < 0.16. The SDSS galaxy catalogue was split into two classes of active galaxies, Type 2 active galactic nuclei (AGN) and composites, and one set of inactive, star-forming/passive galaxies. For each active galaxy, two inactive control galaxies were selected by matching redshift, absolute magnitude, inclination, and radius. The sample of inactive galaxies naturally divides into a red and a blue sequence, while the vast majority of AGN hosts occur along the red sequence. In terms of H, equivalent width (EW), the population of composite galaxies peaks in the valley between the two modes, suggesting a transition population. However, this effect is not observed in other properties such as the colour,magnitude space or colour,concentration plane. Active galaxies are seen to be generally bulge-dominated systems, but with enhanced H, emission compared to inactive red-sequence galaxies. AGN and composites also occur in less dense environments than inactive red-sequence galaxies, implying that the fuelling of AGN is more restricted in high-density environments. These results are therefore inconsistent with theories in which AGN host galaxies are a ,transition' population. We also introduce a systematic 3D spectroscopic imaging survey, to quantify and compare the gaseous and stellar kinematics of a well-selected, distance-limited sample of up to 20 nearby Seyfert galaxies, and 20 inactive control galaxies with well-matched optical properties. The survey aims to search for dynamical triggers of nuclear activity and address outstanding controversies in optical/infrared imaging surveys. [source] Multiwavelength study of the nuclei of a volume-limited sample of galaxies , II.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2007Optical, infrared, radio observations ABSTRACT We present optical and infrared broad-band images, radio maps, and optical spectroscopy for the nuclear region of a sample of nearby galaxies. The galaxies have been drawn from a complete volume-limited sample for which we have already presented X-ray imaging. We modelled the stellar component of the spectroscopic observations to determine the star formation history of our targets. Diagnostic diagrams were used to classify the emission-line spectra and determine the ionizing mechanism driving the nuclear regions. All those sources classified as active galactic nuclei present small Eddington ratios (,10,3,10,6), implying a very slow growth rate of their black holes. We finally investigate the relative numbers of active and normal nuclei as a function of host galaxy luminosity and find that the fraction of active galaxies slowly rises as a function of host absolute magnitude in the MB,,12 to ,22 range. [source] Discovery and analysis of three faint dwarf galaxies and a globular cluster in the outer halo of the Andromeda galaxy,MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2006N. F. Martin ABSTRACT We present the discovery of three faint dwarf galaxies and a globular cluster in the halo of the Andromeda galaxy (M31), found in our MegaCam survey that spans the southern quadrant of M31, from a projected distance of ,50 to ,150 kpc. Though the survey covers 57 deg2, the four satellites lie within 2° of one another. From the tip of the red giant branch (RGB), we estimate that the globular cluster lies at a distance of 631 ± 58 kpc from the Milky Way and along with a ,100 kpc projected distance from M31 we derive a total distance of 175 ± 55 kpc from its host, making it the farthest M31 globular cluster known. It also shows the typical characteristics of a bright globular cluster, with a half-light radius of 2.3 ± 0.2 pc and an absolute magnitude in the V band of MV,0=,8.5 ± 0.3. Isochrone fitting reveals that it is dominated by a very old population with a metallicity of [Fe/H],,1.3. The three dwarf galaxies are revealed as overdensities of stars that are aligned along the RGB tracks in their colour,magnitude diagrams. These satellites are all very faint, with absolute magnitudes in the range ,7.3 ,MV,0,,6.4, and show strikingly similar characteristics with metallicities of [Fe/H],,1.4 and half-light radii of ,120 ± 45 pc, making these dwarf galaxies two to three times smaller than the smallest previously known satellites of M31. Given their faintness, their distance is difficult to constrain, but we estimate them to be between 740 and 955 kpc which places them well within the virial radius of the host galaxy. The panoramic view of the MegaCam survey can provide an unbiased view of the satellite distribution of the Andromeda galaxy and, extrapolating from its coverage of the halo, we estimate that up to 45 ± 20 satellites brighter than MV,,6.5 should be orbiting M31. Hence faint dwarf galaxies cannot alone account for the missing satellites that are predicted by , cold dark matter models, unless they reside in dark matter minihaloes that are more massive than the typical masses of 107 M, currently inferred from their central radial velocity dispersion. [source] Interpretation of the 1998 outburst of the unique X-ray transient CI Camelopardalis (XTE J0421+560)MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2006imon ABSTRACT We present an analysis of the 1998 outburst of the peculiar X-ray binary and X-ray transient CI Cam (XTE J0421+560). We discuss the observations in the framework of several possible models and argue that this outburst can be explained by the thermal instability of the accretion disc, analogous to the outbursts of soft X-ray transients. Applying the model by King & Ritter and Shahbaz, Charles & King on the X-ray light curve, we obtain a realistic mass of the disc at the peak of outburst to be Mh(0) , 1.5 × 1023 g (the distance d= 5 kpc) or 3.8 × 1022 g (d= 2.5 kpc). The disc radius at this moment is then Rh(0) , 2.5 × 1010 cm (d= 5 kpc) or 1.6 × 1010 cm (d= 2.5 kpc), provided that the factor f (the ratio of the mass of the hot disc at that moment with respect to its maximum possible mass) is close to unity. Even if we take a quite low f= 0.05, we still obtain Rh(0) by only 2.7 times larger. The reddening in the outburst maximum and brighter peak absolute magnitude of CI Cam with respect to those of soft X-ray transients in outbursts can be explained if the disc in CI Cam heats up an extended envelope and/or a strong jet is formed. We thus bring firm arguments for Robinson, Ivans & Welsh's hypothesis. On the other hand, we bring the arguments against the mass transfer burst from the donor and the periastron passage of the compact object. [source] Investigation of the ELAIS field by Vega photometry: absolute magnitude-dependent Galactic model parametersMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2006S. Bilir ABSTRACT We estimate the density laws of the Galactic stellar populations as a function of absolute magnitude in a near-polar Galactic field. The density laws are determined by direct fitting to photometric parallaxes from Vega photometry in the ELAIS field (; epoch 2000), both independently for each population and simultaneously for all stellar populations. Stars have been separated into different populations based on their spatial location. The thick disc and halo are fitted best by an exponential. However, the thin disc is fitted best by using a sech2 law for stars at faint absolute magnitudes [10 < M(g,) , 11, 11 < M(g,) , 12 and 12 < M(g,) , 13], and an exponential law for stars at relatively bright absolute magnitudes [5 < M(g,) , 6, 6 < M(g,) , 7, 7 < M(g,) , 8, 8 < M(g,) , 9 and 9 < M(g,) , 10]. The scaleheights for the sech2 density laws are the equivalent exponential scaleheights. Galactic model parameters are dependent on absolute magnitude. The scaleheight for the thin disc decreases monotonically from stars at bright absolute magnitudes [M(g,) = 5] to stars at faint absolute magnitudes [M(g,) = 13] in the range 363,163 pc, except for the minimum H= 211 pc at 9 < M(g,) , 10 where the sech density law fits better. Its local density is flat at bright absolute magnitudes but increases at faint absolute magnitudes. For the thick disc, the scaleheight is flat within the uncertainties. The local space density of the thick disc relative to the local space density for the thin disc is almost flat in the absolute magnitude intervals 5 < M(g,) , 6 and 6 < M(g,) , 7, 7.59 and 7.41 per cent respectively, whereas it decreases down to 3.31 per cent in the absolute magnitude interval 7 < M(g,) , 8. The axial ratio for the halo is ,= 0.60, 0.73 and 0.78 for the absolute magnitude intervals 4 < M(g,) , 5, 5 < M(g,) , 6 and 6 < M(g,) , 7 respectively, and its local space density relative to the local space density for the thin disc is 0.06 and 0.04 per cent for the intervals 5 < M(g,) , 6 and 6 < M(g,) , 7, respectively [the local space density relative to the thin disc could not be derived for the absolute magnitude interval 4 < M(g,) , 5 owing to a lack of the local space density for the thin disc for this interval]. The simultaneous fit of all three stellar populations agrees within uncertainties with the most recent values in the literature. Also, each parameter is close to one of the corresponding parameters estimated for different absolute magnitude intervals in this work, but with one exception: i.e. the scaleheight for the thick disc is relatively small and its error is rather large (H= 760+62,55 pc). [source] Explosion energies, nickel masses and distances of Type II plateau supernovaeMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2003D. K. Nadyozhin ABSTRACT The hydrodynamical modelling of Type II plateau supernova (SNIIP) light curves predicts a correlation between three observable parameters (plateau duration, absolute magnitude and photospheric velocity at the middle of the plateau) on the one hand, and three physical parameters (explosion energy E, mass of the envelope expelled and pre-supernova radius R) on the other. The correlation is used, together with adopted distances from the expanding photosphere method, to estimate and R for a dozen well-observed SNIIP. For this set of supernovae, the resulting value of E varies within a factor of 6 (0.5 ,E/1051 erg , 3), whereas the envelope mass remains within the limits . The pre-supernova radius is typically 200,600 R,, but can reach ,1000 R, for the brightest supernovae (e.g. SN 1992am). A new method of determining the distance of SNIIP is proposed. It is based on the assumption of a correlation between the explosion energy E and the 56Ni mass required to power the post-plateau light curve tail through 56Co decay. The method is useful for SNIIP with well-observed bolometric light curves during both the plateau and radioactive tail phases. The resulting distances and future improvements are discussed. [source] The sizes of disc galaxies in intermediate-redshift clustersMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY: LETTERS (ELECTRONIC), Issue 1 2007S. P. Bamford ABSTRACT We examine how the location of star formation within disc galaxies depends on environment at intermediate redshift. This is achieved by comparing emission-line (rem) and rest-frame B -band (rB) scalelengths for matched samples of 50 field and 19 cluster, star-forming, disc galaxies, with 0.25 ,z, 1.0 and MB,,19.5 mag. We find that at a given rB the majority of our cluster galaxies have rem smaller than those in the field, by 25 per cent on average. These results are compared with studies of local galaxies, which find a very similar behaviour. From the relations of rem and rB versus B -band absolute magnitude (MB) we infer that the difference between the intermediate- z cluster and field samples is mostly attributable to variation in rem at a given MB, while the rB versus MB relation is similar for the two samples. [source] Living alone, lack of a confidant and psychological well-being of elderly women in Singapore: the mediating role of lonelinessASIA-PACIFIC PSYCHIATRY, Issue 1 2010Lena L. Lim Abstract Background: The "feminization of aging" and nuclearization of families calls for research to examine the mental health and well-being of elderly women living alone. This study examined a proposed heuristic model whereby the relationship between living alone and lack of a confidant and psychological well-being is mediated by feeling of loneliness. Methods: Path analysis was performed on data of 1,205 community-living older women aged 55 and above with psychological well-being assessed by depressive symptoms (15-items Geriatric Depression Scale) and SF-12 MCS (mental component summary scale of the 12-item Short-Form Health Survey) quality of life scores assessed at baseline and follow-up 1.5 years later. Results: Goodness-of-fit indices used for the model showed good fits. All of the path coefficients were meaningful in absolute magnitude and significant at P<0.001. Living alone was associated concurrently with lack of a confidant (r=0.11), both of which predicts loneliness (path co-efficient=0.09). Loneliness predicts more depressive symptoms (path coefficient=0.25) and SF-12 MCS (path coefficient=,0.28) at baseline, as well as at follow-up. Conclusion: The findings suggest that loneliness mediates the relationship between living alone, lack of a confidant, and psychological well-being. Living alone becomes detrimental when it leads to loneliness. Social programs directed at elderly women who are living alone should alleviate loneliness through satisfactory interpersonal relationships, and emotional and spiritual support. [source] The evolution of cluster dwarfsASTRONOMISCHE NACHRICHTEN, Issue 9-10 2009D. Harsono Abstract We summarize the results from analyzing six clusters of galaxies at 0.14 < z < 0.40 observed with the Hubble Space Telescope Advanced Camera for Surveys. We derive deep composite luminosity functions in B, g, V, r, i, and z down to absolute magnitude of , ,14 + 5 log h mag. The luminosity functions are fitted by a single Schechter function with MBgVriz * = ,19.8, ,20.9, ,21.9, ,22.0, ,21.7, and ,22.3 mag, and , , ,1.3 for all bands. The data suggests red sequence dominates the luminosity function down to ,6 mag below L*, the dwarf spheroidals regime. Hence, at least at z 0.3, the red sequence is well established and galaxies down to dwarf spheroidals are assembled within these clusters. We do not detect the faint-end upturn (M > ,16) that is observed in lower redshift clusters. If this is real, the faint-end population has originated since z = 0.3 (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] The spectroscopic evolution of V2467 Cyg (Nova Cygni 2007) in the first months after the outburstASTRONOMISCHE NACHRICHTEN, Issue 1 2009R. PoggianiArticle first published online: 2 JAN 200 Abstract We present the spectroscopy of nova V2467 Cyg acquired at the Loiano Observatory, Italy, during the first six months after the outburst. We have used the optical spectroscopy to study the physical properties of the ejected material and the photometry to estimate the nova distance. V2467 Cyg is a fast nova, with decline rates by two or three magnitudes of 7.6 and 14.6 days respectively. The light curve exhibited oscillations during the transition stage. The nova achieved an absolute magnitude at maximum in the range ,8.5, ,9.1. The distance is in the range 2.6, 3.6 kpc. V2467 Cyg showed an early appearance of forbidden lines during the transition stage. Its evolution is similar to the behavior of V1494 Aql (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Contribution of gravitational potential energy differences to the global stress fieldGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 2 2009Attreyee Ghosh SUMMARY Modelling the lithospheric stress field has proved to be an efficient means of determining the role of lithospheric versus sublithospheric buoyancies and also of constraining the driving forces behind plate tectonics. Both these sources of buoyancies are important in generating the lithospheric stress field. However, these sources and the contribution that they make are dependent on a number of variables, such as the role of lateral strength variation in the lithosphere, the reference level for computing the gravitational potential energy per unit area (GPE) of the lithosphere, and even the definition of deviatoric stress. For the mantle contribution, much depends on the mantle convection model, including the role of lateral and radial viscosity variations, the spatial distribution of density buoyancies, and the resolution of the convection model. GPE differences are influenced by both lithosphere density buoyancies and by radial basal tractions that produce dynamic topography. The global lithospheric stress field can thus be divided into (1) stresses associated with GPE differences (including the contribution from radial basal tractions) and (2) stresses associated with the contribution of horizontal basal tractions. In this paper, we investigate only the contribution of GPE differences, both with and without the inferred contribution of radial basal tractions. We use the Crust 2.0 model to compute GPE values and show that these GPE differences are not sufficient alone to match all the directions and relative magnitudes of principal strain rate axes, as inferred from the comparison of our depth integrated deviatoric stress tensor field with the velocity gradient tensor field within the Earth's plate boundary zones. We argue that GPE differences calibrate the absolute magnitudes of depth integrated deviatoric stresses within the lithosphere; shortcomings of this contribution in matching the stress indicators within the plate boundary zones can be corrected by considering the contribution from horizontal tractions associated with density buoyancy driven mantle convection. Deviatoric stress magnitudes arising from GPE differences are in the range of 1,4 TN m,1, a part of which is contributed by dynamic topography. The EGM96 geoid data set is also used as a rough proxy for GPE values in the lithosphere. However, GPE differences from the geoid fail to yield depth integrated deviatoric stresses that can provide a good match to the deformation indicators. GPE values inferred from the geoid have significant shortcomings when used on a global scale due to the role of dynamically support of topography. Another important factor in estimating the depth integrated deviatoric stresses is the use of the correct level of reference in calculating GPE. We also elucidate the importance of understanding the reference pressure for calculating deviatoric stress and show that overestimates of deviatoric stress may result from either simplified 2-D approximations of the thin sheet equations or the assumption that the mean stress is equal to the vertical stress. [source] Modelling stream flow for use in ecological studies in a large, arid zone river, central AustraliaHYDROLOGICAL PROCESSES, Issue 6 2005Justin F. Costelloe Abstract Australian arid zone ephemeral rivers are typically unregulated and maintain a high level of biodiversity and ecological health. Understanding the ecosystem functions of these rivers requires an understanding of their hydrology. These rivers are typified by highly variable hydrological regimes and a paucity, often a complete absence, of hydrological data to describe these flow regimes. A daily time-step, grid-based, conceptual rainfall,runoff model was developed for the previously uninstrumented Neales River in the arid zone of northern South Australia. Hourly, logged stage data provided a record of stream-flow events in the river system. In conjunction with opportunistic gaugings of stream-flow events, these data were used in the calibration of the model. The poorly constrained spatial variability of rainfall distribution and catchment characteristics (e.g. storage depths) limited the accuracy of the model in replicating the absolute magnitudes and volumes of stream-flow events. In particular, small but ecologically important flow events were poorly modelled. Model performance was improved by the application of catchment-wide processes replicating quick runoff from high intensity rainfall and improving the area inundated versus discharge relationship in the channel sections of the model. Representing areas of high and low soil moisture storage depths in the hillslope areas of the catchment also improved the model performance. The need for some explicit representation of the spatial variability of catchment characteristics (e.g. channel/floodplain, low storage hillslope and high storage hillslope) to effectively model the range of stream-flow events makes the development of relatively complex rainfall,runoff models necessary for multisite ecological studies in large, ungauged arid zone catchments. Grid-based conceptual models provide a good balance between providing the capacity to easily define land types with differing rainfall,runoff responses, flexibility in defining data output points and a parsimonious water-balance,routing model. Copyright © 2004 John Wiley & Sons, Ltd. [source] Multilevel Anthropogenic Cycles of Copper and Zinc: A Comparative Statistical AnalysisJOURNAL OF INDUSTRIAL ECOLOGY, Issue 1-2 2006Barbara Reck Contemporary cycles for copper and zinc are coanalyzed with the tools of exploratory data analysis. One-year analyses (circa 1994) are performed at three discrete spatial levels-country (52 countries that comprise essentially all anthropogenic stocks and flows of the two metals), eight world regions, and the planet as a whole-and are completed both in absolute magnitude and in per capita terms. This work constitutes, to our knowledge, the first multiscale, multilevel analysis of anthropogenic resources throughout their life cycles. The results demonstrate that (1) A high degree of correlation exists between country-level copper and country-level zinc rates of fabrication and manufacturing, entry into use, net addition to in-use stocks, discard, and landfilling; (2) Regional-level rates for copper and zinc cycle parameters show the same correlations as exist at country level; (3) On a per capita basis, countries add to in-use stock almost 50% more copper than zinc; (4) The predominant discard streams for copper and zinc at the global level are different for the two metals, and relative rates of different loss processes differ geographically, so that resource recovery policies must be designed from metalspecific and location-specific perspectives; (5)When absolute magnitudes of life-cycle flows are considered, the standard deviations of the data sets decrease from country level to regional level for both copper and zinc, which is not the case for the per capita data sets, where the statistical properties of the dat sets for both metals approach being independent of spatial level, thus providing a basis for predicting unmeasured per capita metal flow behavior. [source] 15N NMR coordination shifts in Pd(II), Pt(II), Au(III), Co(III), Rh(III), Ir(III), Pd(IV), and Pt(IV) complexes with pyridine, 2,2,-bipyridine, 1,10-phenanthroline, quinoline, isoquinoline, 2,2,-biquinoline, 2,2,:6,, 2,-terpyridine and their alkyl or aryl derivativesMAGNETIC RESONANCE IN CHEMISTRY, Issue S1 2008Leszek Pazderski Abstract The 15N NMR data for 105 complexes of Pd(II), Pt(II), Au(III), Co(III), Rh(III), Ir(III), Pd(IV), and Pt(IV) complexes with simple azines such as pyridine, 2,2,-bipyridine, 1,10-phenanthroline, quinoline, isoquinoline, 2,2,-biquinoline, 2,2':6', 2"-terpyridine and their alkyl or aryl derivatives have been reviewed. The 15N NMR coordination shifts, i.e. the differences between the 15N chemical shifts of the same nitrogen in the molecules of the complex and the ligand (,15Ncoord = ,15Ncompl , ,15Nlig), have been related to some structural features of the reviewed coordination compounds, like the type of the central ion and the character of auxiliary ligands (mainly in trans position). These ,15Ncoord parameters are negative, their absolute magnitudes (ca 30,150 ppm) generally increasing in the metal order Au(III) < Pd(II) < Pt(II) and Rh(III) < Co(III) < Pt(IV) < Ir(III), as well as with the enhanced trans influence of the other donor atoms (H, C , Cl < N). Copyright © 2008 John Wiley & Sons, Ltd. [source] Discovery and analysis of three faint dwarf galaxies and a globular cluster in the outer halo of the Andromeda galaxy,MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2006N. F. Martin ABSTRACT We present the discovery of three faint dwarf galaxies and a globular cluster in the halo of the Andromeda galaxy (M31), found in our MegaCam survey that spans the southern quadrant of M31, from a projected distance of ,50 to ,150 kpc. Though the survey covers 57 deg2, the four satellites lie within 2° of one another. From the tip of the red giant branch (RGB), we estimate that the globular cluster lies at a distance of 631 ± 58 kpc from the Milky Way and along with a ,100 kpc projected distance from M31 we derive a total distance of 175 ± 55 kpc from its host, making it the farthest M31 globular cluster known. It also shows the typical characteristics of a bright globular cluster, with a half-light radius of 2.3 ± 0.2 pc and an absolute magnitude in the V band of MV,0=,8.5 ± 0.3. Isochrone fitting reveals that it is dominated by a very old population with a metallicity of [Fe/H],,1.3. The three dwarf galaxies are revealed as overdensities of stars that are aligned along the RGB tracks in their colour,magnitude diagrams. These satellites are all very faint, with absolute magnitudes in the range ,7.3 ,MV,0,,6.4, and show strikingly similar characteristics with metallicities of [Fe/H],,1.4 and half-light radii of ,120 ± 45 pc, making these dwarf galaxies two to three times smaller than the smallest previously known satellites of M31. Given their faintness, their distance is difficult to constrain, but we estimate them to be between 740 and 955 kpc which places them well within the virial radius of the host galaxy. The panoramic view of the MegaCam survey can provide an unbiased view of the satellite distribution of the Andromeda galaxy and, extrapolating from its coverage of the halo, we estimate that up to 45 ± 20 satellites brighter than MV,,6.5 should be orbiting M31. Hence faint dwarf galaxies cannot alone account for the missing satellites that are predicted by , cold dark matter models, unless they reside in dark matter minihaloes that are more massive than the typical masses of 107 M, currently inferred from their central radial velocity dispersion. [source] Investigation of the ELAIS field by Vega photometry: absolute magnitude-dependent Galactic model parametersMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2006S. Bilir ABSTRACT We estimate the density laws of the Galactic stellar populations as a function of absolute magnitude in a near-polar Galactic field. The density laws are determined by direct fitting to photometric parallaxes from Vega photometry in the ELAIS field (; epoch 2000), both independently for each population and simultaneously for all stellar populations. Stars have been separated into different populations based on their spatial location. The thick disc and halo are fitted best by an exponential. However, the thin disc is fitted best by using a sech2 law for stars at faint absolute magnitudes [10 < M(g,) , 11, 11 < M(g,) , 12 and 12 < M(g,) , 13], and an exponential law for stars at relatively bright absolute magnitudes [5 < M(g,) , 6, 6 < M(g,) , 7, 7 < M(g,) , 8, 8 < M(g,) , 9 and 9 < M(g,) , 10]. The scaleheights for the sech2 density laws are the equivalent exponential scaleheights. Galactic model parameters are dependent on absolute magnitude. The scaleheight for the thin disc decreases monotonically from stars at bright absolute magnitudes [M(g,) = 5] to stars at faint absolute magnitudes [M(g,) = 13] in the range 363,163 pc, except for the minimum H= 211 pc at 9 < M(g,) , 10 where the sech density law fits better. Its local density is flat at bright absolute magnitudes but increases at faint absolute magnitudes. For the thick disc, the scaleheight is flat within the uncertainties. The local space density of the thick disc relative to the local space density for the thin disc is almost flat in the absolute magnitude intervals 5 < M(g,) , 6 and 6 < M(g,) , 7, 7.59 and 7.41 per cent respectively, whereas it decreases down to 3.31 per cent in the absolute magnitude interval 7 < M(g,) , 8. The axial ratio for the halo is ,= 0.60, 0.73 and 0.78 for the absolute magnitude intervals 4 < M(g,) , 5, 5 < M(g,) , 6 and 6 < M(g,) , 7 respectively, and its local space density relative to the local space density for the thin disc is 0.06 and 0.04 per cent for the intervals 5 < M(g,) , 6 and 6 < M(g,) , 7, respectively [the local space density relative to the thin disc could not be derived for the absolute magnitude interval 4 < M(g,) , 5 owing to a lack of the local space density for the thin disc for this interval]. The simultaneous fit of all three stellar populations agrees within uncertainties with the most recent values in the literature. Also, each parameter is close to one of the corresponding parameters estimated for different absolute magnitude intervals in this work, but with one exception: i.e. the scaleheight for the thick disc is relatively small and its error is rather large (H= 760+62,55 pc). [source] Transformations between the 2MASS, SDSS, and BVI photometric systems for late-type giantsASTRONOMISCHE NACHRICHTEN, Issue 8 2010E. Yaz Abstract We present colour transformations from Two Micron All Sky Survey (2MASS) photometric system to Johnson-Cousins system and to Sloan Digital Sky Survey (SDSS) system for late-type giants and vice versa. The giant star sample was formed using surface gravity constraints (2 < log g , 3) to Cayrel de Strobel et al.'s (2001) spectroscopic catalogue. 2MASS, SDSS and Johnson-Cousins photometric data was taken from Cutri et al. (2003), Ofek (2008), and van Leeuwen (2007), respectively. The final sample was refined applying the following steps: (1) the data were dereddened, (2) the sample stars selected are of the highest photometric quality. We give two-colour dependent transformations as a function of metallicity as well as independent of metallicity. The transformations provide absolute magnitudes and distance determinations which can be used in space density evaluations at relatively short distances where some or all of the SDSS magnitudes of late-type giants are saturated (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Eight new and three recalculated orbits for binariesASTRONOMISCHE NACHRICHTEN, Issue 3 2010Z. Cvetkovi Abstract In this paper new orbital elements are given for eleven binaries. For eight of them, WDS 00003,4417 = I 1477, WDS 00106,7313 = I 43 AB, WDS 00366+5609 = A 914, WDS 00519,4343 = I 47, WDS 01315+1521 = BU 506, WDS 01577+4434 = A 1526, WDS 08144,4550 = FIN 113 AB and WDS 08291,4756 = FIN 315 Aa-Ab, the orbital elements are calculated for the first time. For three of them, WDS 04422+2257 = MCA 16 Aa-Ab, WDS 08275,5501 = FIN 116 and WDS 14567,6247 = FIN 372, the orbital elements are recalculated. One of the eleven binaries, MCA 16 Aa-Ab, was discovered by McAlister in 1980 by speckle interferometry and four pairs were discovered by Finsen between 1929 and 1960. For these five pairs, all measured separations are less than 0,.4 and most of the observations were done by using the interferometric techniques. The orbital periods calculated here are between 39 and 270 years. The remaining six pairs were discovered between 1878 and 1926 and most of the observations are visual. They have longer orbital periods, between 384 and 1637 years. In addition to the orbital elements the masses, dynamical parallaxes, absolute magnitudes and ephemerides for the next five years are also given in this paper (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] The total-to-selective extinction ratio determined from near IR photometry of OB starsASTRONOMISCHE NACHRICHTEN, Issue 3 2003W. WegnerArticle first published online: 8 APR 200 Abstract The paper presents an extensive list of the total to selective extinction ratios R calculated from the infrared magnitudes of 597 O and B stars using the extrapolation method. The IR magnitudes of these stars were taken from the literature. The IR colour excesses are determined with the aid of "artificial standards" , Wegner (1994). The individual and mean values of total to selective extinction ratios R differ in most cases from the average value R= 3.10 ±0.05 , Wegner (1993) in different OB associations. The relation between total to selective extinction ratios R determined in this paper and those calculated using the "method of variable extinction" and the Cardelli et al. (1989) formulae is discussed. The R values presented in this paper can be used to determine individual absolute magnitudes of reddened OB stars with known trigonometric parallaxes. [source] | ||||||||||||||||||||||