bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of pressure and mineralogy on seismic velocities in oceanic gabbros: Implications for the composition and state of the lower oceanic crust
Authors: Carlson R. L. , Jay Miller D.
Published: September 2004

We have analyzed the relationship between P wave velocities, measured at pressures of 40, 100, and 200 MPa, and modal mineralogy in oceanic gabbro samples from Ocean Drilling Program Holes 735B, 894G, and 923A. At all pressures, increasing velocities correspond to increasing pyroxene contents and decreasing alteration (phyllosilicate and amphibole content) but indicate little or no variation of olivine content, in part because the olivine compositions are in the range Fo65 to Fo73. A Voigt‐Reuss‐Hill inverse model reveals that the effective bulk density and elastic moduli of olivine in the gabbros are low, even relative to Fo73, possibly because the olivine grains contain ubiquitous networks of cracks. Even if the cracks are not present in situ, on average, gabbros with velocities typical of seismic layer 3 (6.7–7.0 km s−1) contain 5–15% alteration products, including 5–15% amphibole and 0–5% phyllosilicates. These results suggest that the lower crust is, on average, slightly to moderately altered.
Distributions and variability of particulate organic matter in a coastal upwelling system
Authors: Karp‐Boss L. , Wheeler P. A. , Hales B. , Covert P.
Published: September 2004

In this study we examined the spatial and temporal variability of particulate organic material (POM) off Oregon during the upwelling season. High‐resolution vertical profiling of beam attenuation was conducted along two cross‐shelf transects. One transect was located in a region where the shelf is relatively uniform and narrow (off Cascade Head (CH)); the second transect was located in a region where the shelf is shallow and wide (off Cape Perpetua (CP)). In addition, water samples were collected for direct analysis of chlorophyll, particulate organic carbon (POC), and particulate organic nitrogen (PON). Beam attenuation was highly correlated with POC and PON. Striking differences in distribution patterns and characteristics of POM were observed between CH and CP. Off CH, elevated concentrations of chlorophyll and POC were restricted to the inner shelf and were highly variable in time. The magnitude of the observed short‐term temporal variability was of the same order as that of the seasonal variability reported in previous studies. Elevated concentrations of nondegraded chlorophyll and POM were observed near the bottom. Downwelling and rapid sinking are two mechanisms by which phytoplankton cells can be delivered to the bottom before being degraded. POM may be then transported across the shelf via the benthic nepheloid layer. Along the CP transect, concentrations of POM were generally higher than they were along the CH transect and extended farther across the shelf. Characteristics of surface POM, namely, C:N ratios and carbon:chlorophyll ratios, differed between the two sites. These differences can be attributed to differences in shelf circulation.
Global distribution of near‐surface hydrogen on Mars
Authors: Feldman W. C. , Prettyman T. H. , Maurice S. , Plaut J. J. , Bish D. L. , Vaniman D. T. , Mellon M. T. , Metzger A. E. , Squyres S. W. , Karunatillake S. , Boynton W. V. , Elphic R. C. , Funsten H. O. , Lawrence D. J. , Tokar R. L.
Published: September 2004

Neutron data observed using the Neutron Spectrometer aboard 2001 Mars Odyssey provide a lower limit to the global inventory of Martian water‐equivalent hydrogen. Hydrogen‐rich deposits ranging between about 20% and 100% water‐equivalent by mass are found poleward of ±50° latitude, and less rich, but significant, deposits are found at near‐equatorial latitudes. The equatorial deposits between ±45° latitude range between 2% and 10% water‐equivalent hydrogen by mass and reach their maximum in two regions that straddle the 0‐km elevation contour. Higher water abundances, up to ∼11%, are required in subsurface regolith of some equatorial regions if the upper 10 g/cm2of regolith is desiccated, as suggested on average by comparison of epithermal and fast neutron data. The hydrogen contents of surface soils in the latitude range between 50° and 80° north and south are equal within data uncertainties. A lower‐limit estimate of the global inventory of near surface hydrogen amounts to a global water layer about 14 cm thick if the reservoir sampled from orbit is assumed to be 1 m thick.
Gravity‐inferred crustal attributes of visible and buried impact basins on Mars
Authors: Potts Laramie V. , von Frese Ralph R. , Leftwich Timothy E. , Taylor Patrick T. , Shum C. K. , Li Rongxing
Published: September 2004

The impact basins of Mars reveal important insights on Martian tectonic evolution. They involve strongly disrupted, depressed regions of crust with likely enhanced porosity and permeability that may locally concentrate water and other crustal fluids. Hence the crustal properties of impact basins can also be important in the hunt for water and related clues for life on Mars. We assess the crustal details of impact basins by separating the Mars Global Surveyor free‐air anomalies into terrain‐correlated and terrain‐decorrelated components. The separation is based on the correlation spectrum between the free‐air anomalies and the gravity effects evaluated from the topography mapped by the Mars Orbital Laser Altimeter (MOLA). For topographically visible multiring basins like Isidis, striking circular patterns of alternating terrain‐correlated free‐air maxima and minima mark the uncompensated components of the central mantle plug and surrounding rings. The first vertical derivatives of these anomalies effectively estimate the basin ring locations and a transient cavity depth‐to‐diameter ratio of 0.09 that is consistent with the ratio observed for lunar nearside multiring basins. For the Isidis Basin we obtain an excavation depth of roughly 66 km that reflects considerably disrupted crust for concentrating local fluids since the Noachian impact. Furthermore, the related crustal terrain‐decorrelated free‐air anomalies suggest up to 2 km of high‐density basin fill may cap the central basin. Subtle quasi‐circular depressions in the relatively featureless MOLA terrain of the northern hemisphere have identified potentially buried impact basins [Frey et al., 2002]. An altimetry depression in Acidalia Planitia and another in Utopia are also associated with ringed patterns of terrain‐decorrelated free‐air anomalies that may mark the uncompensated mass effects of buried impact basins. The gravity‐derived transient excavation depths for these inferred basins are roughly 41 and 20 km, respectively, while the related ring diameters (D) follow the ubiquitous D rule of planetary impact basins. The crust of these buried basins is likely to contain water at higher levels than the crust of the equatorial basins that was substantially dewatered with the development of the great northern basin. Hence analyzing surface fractures, faults, and other crustal discontinuities that can tap the more saturated crust of these inferred buried basins may facilitate the hunt for water on Mars.
A numerical study of a mantle plume beneath the Tharsis Rise: Reconciling dynamic uplift and lithospheric support models
Authors: Redmond Hannah L. , King Scott D.
Published: September 2004

The Tharsis Rise is an area of extensive volcanism containing the most significant long‐wavelength topographic and areoid anomalies on Mars. The mechanism for supporting this large topographic expression and correlating areoid remains controversial. The two main competing ideas are dynamic support by a deep, mantle plume and a volcanically constructed lithosphere followed by lithospheric flexure. While both of these models, separately, can account for specific features of Tharsis, neither explain its entirety. Most of the support of the Tharsis topographic anomaly is best explained by a volcanic structure modifying the lithosphere. However, this raises the important question of the origin of the heat source for volcanic construction, leading to possible small‐scale convection. This demonstrates that the remaining topography and areoid not accounted for in lower end‐members of volcanically constructed surface loads is consistent with a deeper, mantle plume source. Our results show we can produce about 15% and 18% of the total Tharsis long‐wavelength areoid and topography anomaly with a plume forming in a strong, temperature‐dependent rheology. Additionally, our plume model has a 165 km thick rheological lithosphere (within the range for present‐day estimates on Mars) and generates about 1% partial melting, more than sufficient to provide a heat source for recent volcanism. This implies both a model with dynamic support from a plume and a volcanically constructed lithosphere not only can coexist but offer an explanation for both the surface anomalies and heat needed for the minor amount of recent volcanic activity at Tharsis Rise.
Initial test of the silicic acid leakage hypothesis using sedimentary biomarkers
Authors: Higginson Matthew J. , Altabet Mark A.
Published: September 2004

Several mechanisms have been proposed for large CO2 changes at glacial Terminations, including shifting the CaCO3:Corg rain ratio by changing surface water nutrient supply, altering the balance between diatom and coccolithophore production. Diatom Si:N is highest in Fe‐stressed high‐latitude waters. Southern Ocean Fe enrichment studies suggest diatom Si demands reduced under Fe‐replete (glacial) conditions, allowing increased silicic acid to leak northward in subducted intermediate water and upwell at lower latitudes. We test this ‘Silicic Acid Leakage’ hypothesis using relative abundances of phytoplankton‐specific biomarkers in Peru margin sediments spanning 0–20 Ka. Results indicate increased coccolithophorid:diatom production from ∼0.5 to 3 between 18.0–15.5 Ka. Temporal correlation with the initial pCO2 rise and early deglacial shift in mode water ventilation implicates a coincidental, possibly causative reorganization of Sub‐Antarctic Mode Water formation and reduced Fe abundance. However, coccolithophorid production subsequently declined, suggesting rain ratio changes were only partly responsible for the CO2 deglacial transition.
Tropical Pacific upper ocean heat content variations and Indian summer monsoon rainfall
Authors: Rajeevan M. , McPhaden Michael J.
Published: September 2004

Indian southwest monsoon rainfall (ISMR) has strong links with El Niño/Southern Oscillation (ENSO). However, sea surface temperature (SST) anomalies during the pre‐monsoon season do not have any predictive value for ensuing monsoon rainfalls. Recent studies have suggested that warm water volume (WWV) in the tropical Pacific Ocean in boreal winter is a good precursor of ENSO warm and cold events (El Niño and La Niña). In this study, we have analyzed inter‐annual variations in the WWV in the tropical Pacific Ocean and Indian summer monsoon rainfall (ISMR) using upper ocean thermal field analyses spanning 54 years (1950–2003). Significant negative correlations have been observed between WWV anomalies in the boreal winter and spring seasons and ISMR, with deficient (excess) monsoon years corresponding to positive (negative) WWV anomalies. This relationship provides a much longer lead time than ENSO SST indicators for prediction of ensuing monsoon rainfall. Twenty‐one year moving correlations show that the correlation between WWV anomalies in boreal winter and spring and subsequent ISMR anomalies has strengthened since the mid‐1980s.
Accelerated ice discharge from the Antarctic Peninsula following the collapse of Larsen B ice shelf
Authors: Rignot E. , Casassa G. , Gogineni P. , Krabill W. , Rivera A. , Thomas R.
Published: September 2004

Interferometric synthetic‐aperture radar data collected by ERS‐1/2 and Radarsat‐1 satellites show that Antarctic Peninsula glaciers sped up significantly following the collapse of Larsen B ice shelf in 2002. Hektoria, Green and Evans glaciers accelerated eightfold between 2000 and 2003 and decelerated moderately in 2003. Jorum and Crane glaciers accelerated twofold in early 2003 and threefold by the end of 2003. In contrast, Flask and Leppard glaciers, further south, did not accelerate as they are still buttressed by an ice shelf. The mass loss associated with the flow acceleration exceeds 27 km3 per year, and ice is thinning at rates of tens of meters per year. We attribute this abrupt evolution of the glaciers to the removal of the buttressing ice shelf. The magnitude of the glacier changes illustrates the importance of ice shelves on ice sheet mass balance and contribution to sea level change.
Substantial traffic emissions contribution to the global H2S budget
Authors: Kourtidis K. , Kelesis A. , Maggana M. , Petrakakis M.
Published: September 2004

One year of hydrogen sulfide measurements in an urban traffic site were used to assess the importance of traffic in the overall high ambient air burden of H2S (mean annual concentration of 8 μg/m3). During calm nighttime hours, hourly values of H2S were correlated positively with those of CO (R2 = 0.75) and SO2 (R2 = 0.70), suggesting a common source from traffic. For the driving conditions of the measurement site, H2S automotive emissions are around 24% w/w those of SO2, while European inventories calculate these at only 2.5%. H2S annual traffic emissions, based on the existing emission inventories for CO and SO2 are calculated at 0.199–0.311 × 10−3 Tg a−1 for Thessaloniki and are extrapolated to 0.030–0.0485 Tg a−1 for the EU15 countries and 2.6 Tg a−1 for Europe and Eurasia. It appears that traffic emissions make up a significant contribution to the global H2S budget.
On magnetic reconnection regimes and associated three‐dimensional asymmetries: Hybrid, Hall‐less hybrid, and Hall‐MHD simulations
Authors: Karimabadi H. , Krauss‐Varban D. , Huba J. D. , Vu H. X.
Published: September 2004

Magnetic reconnection in a plane current sheet is investigated in both two and three dimensions, using three different types of simulation codes, Hall MHD, hybrid (electron fluid, kinetic ions), and a new code called Hall‐less hybrid. The latter code, which is similar to the hybrid code but has the Hall term removed, enables us to clarify the differences between kinetic ion and Hall MHD approaches. The major findings of this research are (1) Sweet‐Parker regime of reconnection cannot be maintained and does not reach a steady state in a kinetic plasma for physically interesting parameter regimes. (2) Fast asymptotic reconnection rate of 0.15VA0B0 is obtained both in the hybrid and Hall‐less hybrid simulations with outflow boundaries. VA0 and B0 are the Alfvén velocity and magnetic field strength in the upstream region. This finding has two immediate implications. First, ion kinetics are sufficient to lead to fast reconnection even in the absence of the Hall term, and second, explanation of fast reconnection in terms of quadratic disperion of whistlers needs to be reconsidered, as whistlers are dispersionless in Hall‐less hybrid limit. (3) Unlike in MHD, diffusion region is different in size that the region of localized resistivity. (4) While both Hall and hybrid codes show that reconnection is inherently asymmetric in three dimensions, there are differences in the nature of the asymmetry. In Hall MHD we show that the X‐line grows in the direction of the electron drift, propagating as a (reconnection) wave because the current is carried by electrons, although the wave direction can change in the presence of a substantial ion flow. However, in the hybrid simulations here, as is the case for typical conditions at the magnetopause and magnetotail, ions carry the bulk of the current, and the observed asymmetry is found to be due to ion flow and not a wave motion unless the extent of finite resistivity in the third dimension is very thin, comparable to the current sheet thickness. Thus aside from scenarios where electrons are the dominant current carriers, such as very thin current sheets that are on electron scales, we do not expect the reconnection wave to form. This result is relevant to the magnetotail where dawn‐dusk asymmetries are observed in the motions of auroral brightenings and surges, as well as in the statistical location of pressure decreases, flows, and magnetic signatures associated with the near‐Earth neutral line and early plasmoids. We attribute the observed dawn‐dusk asymmetries to ion flows. One interesting question left for future work is the possibility that reconnection waves may form in thin electron‐scale current layers that are sometimes observed embedded within a thicker sheet in the magnetotail.
Onset and amplitude of the 11‐year solar modulation of cosmic ray intensities at the Earth and at Voyagers 1 and 2 during the period from 1997 to 2003
Authors: Webber W. R. , Lockwood J. A.
Published: September 2004

We have examined the intensity changes of galactic and anomalous cosmic rays at five rigidities and at three heliocentric radii, 1 AU, ∼60 AU, and ∼80 AU, between the maximum 11‐year solar cycle intensity observed in 1997–1998 and the minimum intensity observed in 2001. The main results of this paper are as follows. (1) The onset of the intensity decrease in the outer heliosphere is delayed by 1–2 years from that observed at Earth. Most of the intensity decrease at both the Earth and Voyagers 1 and 2 occurs at the time of the solar magnetic polarity change from positive to negative. (2) The amplitude of this 11‐year intensity decrease is strongly dependent on heliospheric radius. It is only ∼1/3 as large at Voyager 2 located at ∼60 AU and ∼1/6 as large at Voyager 1 located at ∼80 AU for all galactic particles. This radial dependence extrapolates to a zero modulation in this positive solar magnetic polarity cycle at a distance ∼90–100 AU. This strong radial dependence of the intensity changes is in contrast to that observed in the previous negative polarity cycle where the radial effects were much smaller. (3) The dependence on the rigidity, P, of the modulation observed at all the three locations follows a simple P−1 dependence between ∼0.6 and 2.5 GV. The relative modulation of anomalous O nuclei is ∼5.35 times that for galactic nuclei at the same rigidity of 2.4 GV. This is just the ratio of speeds of anomalous O and galactic H and He nuclei at this rigidity.
Characteristics of Saturn's FUV aurora observed with the Space Telescope Imaging Spectrograph
Authors: Gérard Jean‐Claude , Grodent Denis , Gustin Jacques , Saglam Adem , Clarke John T. , Trauger John T.
Published: September 2004

We analyze a set of 15 FUV images obtained between October 1997 and January 2001 with the Hubble Space Telescope Imaging Spectrograph (STIS), providing a good view of Saturn's south auroral oval. It is found that the morphology and brightness distribution of the aurora are dynamical with variations occurring on time scales of hours or less. The dayside main oval lies between 70° and 80° and is generally brighter and thinner in the morning than in the afternoon sector. The afternoon sector is characterized by more diffuse emission at higher latitudes. Weak emission is also observed poleward of the main oval up to the pole. A spot of enhanced auroral precipitation, tentatively identified as the optical signature of the dayside cusp, is sometimes observed poleward of the main oval in the noon sector, especially during periods when the morning arc is not fully developed. A spiral structure of the main oval with arcs at two latitudes in the same sector is occasionally observed. The brightness of the main oval ranges from below the STIS threshold of 1 kR of H2 emission up to ∼75 kR. The total electron precipitated power varies between 20 and 140 GW, that is, comparable to the Earth's active aurora but about two orders of magnitude less than on Jupiter. An increasing trend of the precipitated power between the 1997 and the 2000–2001 observations may be related to the rising solar activity. Six spectra of the aurora in the noon sector covering the 1200–1700 Å range are dominated by emissions of the Lyman‐α line and H2 Werner and Lyman bands. Their comparison with a synthetic model of electron excited H2 emissions indicates the presence of a weak absorption below 1400 Å by a column of methane ranging between 7 × 1015 and 2 × 1016 cm−2. The corresponding energy of the primary auroral electrons is estimated 12 ± 3 keV, using a low‐latitude model atmosphere based on Voyager occultation measurements. The main oval brightness and the characteristic electron energy are generally consistent with recent models of Saturn's aurora, which colocate the main oval with the narrow upward field‐aligned current system associated with departure from plasma corotation near the open‐closed field line boundary. The latitude of the bright morning arc is somewhat lower than model predictions based on the plasma flow velocity measured by Voyager in the middle magnetosphere.
Crustal structure of the northern Nova Scotia rifted continental margin (eastern Canada)
Authors: Funck Thomas , Jackson H. Ruth , Louden Keith E. , Dehler Sonya A. , Wu Yue
Published: September 2004

The Nova Scotia continental margin off eastern Canada marks a transition from a volcanic to a nonvolcanic style of rifting. The northern (nonvolcanic) segment of the margin was studied by a 490‐km‐long refraction seismic line with dense air gun shots, coincident with previous deep reflection profiles. APwave velocity model was developed from forward and inverse modeling of the wide‐angle data from 19 ocean bottom seismometers and coincident normal incidence reflection profiles. The continental crust has a maximum thickness of 36 km and is divided into three layers with velocities of 5.7–6.9 km/s. Crustal thinning down to 3 km occurs in a 180‐km‐wide zone and the sediment cover in this area is up to 15 km thick. Farther seaward, a 150‐km‐wide transition zone is observed with a 5‐km‐thick lower layer (7.2–7.6 km/s) interpreted as partially serpentinized mantle. At the landward end, this layer is overlain by highly altered continental crust (5.4 km/s) extending up to the seaward limit of the Jurassic salt province. Farther seaward, the upper layer is interpreted as exhumed and highly serpentinized mantle (5.1 km/s) separated from the lower layer by subhorizontal reflectivity, which probably represents a serpentinization front. Oceanic crustal thickness is 4 km with layer 2 velocities of 4.6–5.0 km/s. Layer 3 velocities of 6.4–6.55 km/s are lower than typical lower oceanic crust velocities but consistent with a low magma supply and increased tectonism as observed on the reflection profile. This reduced magma production might be related to the proximity of the Newfoundland transform margin.
Simulation of the cold climate event 8200 years ago by meltwater outburst from Lake Agassiz
Authors: Bauer E. , Ganopolski A. , Montoya M.
Published: September 2004

The cold climate anomaly about 8200 years ago is investigated with CLIMBER‐2, a coupled atmosphere‐ocean‐biosphere model of intermediate complexity. This climate model simulates a cooling of about 3.6 K over the North Atlantic induced by a meltwater pulse from Lake Agassiz routed through the Hudson strait. The meltwater pulse is assumed to have a volume of 1.6 × 1014 m3 and a period of discharge of 2 years on the basis of glaciological modeling of the decay of the Laurentide Ice Sheet (LIS). We present a possible mechanism which can explain the centennial duration of the 8.2 ka cold event. The mechanism is related to the existence of an additional equilibrium climate state with reduced North Atlantic Deep Water (NADW) formation and a southward shift of the NADW formation area. Hints at the additional climate state were obtained from the largely varying duration of the pulse‐induced cold episode in response to overlaid random freshwater fluctuations in Monte Carlo simulations. The model equilibrium state was attained by releasing a weak multicentury freshwater flux through the St. Lawrence pathway completed by the meltwater pulse. The existence of such a climate mode appears essential for reproducing climate anomalies in close agreement with paleoclimatic reconstructions of the 8.2 ka event. The results furthermore suggest that the temporal evolution of the cold event was partly a matter of chance.
A solar (irradiance) trigger for millennial‐scale abrupt changes in the southwest monsoon?
Authors: Higginson Matthew J. , Altabet Mark A. , Wincze Lauren , Herbert Timothy D. , Murray David W.
Published: September 2004

Marine sedimentary records of the last glacial from tropical monsoon latitudes indicate climate fluctuations comparable to rapid changes in δ18O recorded in Greenland. Synchronizing two high‐resolution sedimentary records from the Oman and Pakistan margins, we resolve millennial‐scale reversals in sea surface temperature (SST) gradient (ΔSST) across the Arabian Sea which directly correspond with the majority of Dansgaard‐Oeschger (D‐O) events for the last 65 kyr. The relative amplitude of individual monsoon and D‐O events appears comparable, suggesting coupled and at least hemispheric forcing. To explore this quasi‐cyclic forcing, we compare alkenone‐based geologic data with modern satellite‐derived ΔSST estimates between sites. Interstadial conditions fall within the range of monsoons during the Holocene, but stadial conditions have no analogs. Following published associations between Eurasian Winter Snow Cover (EWSC) and monsoon rainfall, and El Niño/Southern Oscillation (ENSO) events and anomalous EWSC, we find a good correlation between the Southern Oscillation Index (SOI) and Arabian Sea ΔSST throughout the modern data set. An apparent 11‐year cyclicity in the SOI reveals an association between the monsoon, SOI, and solar output variability. The SOI primarily tracks solar total irradiance, but the SOI monsoon linkage becomes nonlinear during excursions of the SOI associated with El Niño Events. Strong El Niños coincide precisely with minimum solar irradiance during the solar cycle, which we attribute to threshold behavior in tropical Pacific SSTs and associated trade wind strength. We propose that both short‐term (interannual‐decadal) and long‐term (centennial‐millennial) changes in solar output are consistent with records of ENSO variability, monsoon intensity, and D‐O event timing.
Importance of groundwater sulfate to acidification in the Goose River watershed, Maine
Authors: Sidle William C. , Allen Derrick
Published: September 2004

The role of groundwater sulfate discharge to ponds and streams within the Goose River basin (33.3 km2) is examined. While airborne sulfate deposition has declined, acidity in surface waters locally remains elevated. Monthly SO42− analyses (1999–2002) of wet deposition and surface waters are reported, and a sulfate budget for six catchments of the Goose River watershed, Maine is calculated. Groundwater values from different bedrock types are beneficial in identifying groundwater source(s) of sulfate in surface waters and discriminating them from atmospheric sulfate deposition. The variability of proposed sulfide oxidation among certain local chalcophile rocks and the depth of aeration in these sheared granitoids are elucidated from and data. Cosmogenic residence times estimate new atmospheric SO42− deposition in the catchments and production of SO42− from water‐rock interactions among some fractured granitoids.
Multifaceted Nature of Intrinsic Motivation: The Theory of 16 Basic Desires
Authors: Reiss Steven
Published: September 2004

R. W. White (1959) proposed that certain motives, such as curiosity, autonomy, and play (called intrinsic motives, or IMs), have common characteristics that distinguish them from drives. The evidence that mastery is common to IMs is anecdotal, not scientific. The assertion that “intrinsic enjoyment” is common to IMs exaggerates the significance of pleasure in human motivation and expresses the hedonistic fallacy of confusing consequence for cause. Nothing has been shown scientifically to be common to IMs that differentiates them from drives. An empirically testable theory of 16 basic desires is put forth based on psychometric research and subsequent behavior validation. The desires are largely unrelated to each other and may have different evolutionary histories.
Social and Individual Coping with Threats: Outlines of an Interdisciplinary Approach
Authors: Greve Werner , Strobl Rainer
Published: September 2004

Referring to a general conception of coping as an adaptive reaction to a perceived is-ought discrepancy, the authors present an interdisciplinary perspective on coping processes. Based on systems theory, a psychological view is compared with a sociological perspective, focusing structural equivalencies between social and individual adaptational processes. Defensive, proactive, and accommodative reactions are discussed as 3 general modes of coping. It is argued that all of these coping reactions in both individuals and social systems have specific costs and benefits, which are particularly visible if the interaction and “interpenetration” between the coping strategies of individuals and social systems are observed.
Contextual Politics of Difference in Transnational Care: The Rhetoric of Filipino Domestics’ Employers in Taiwan
Authors: Cheng Shu-Ju Ada
Published: September 2004

The construction of foreign domestics as ‘Others’ has been a critical process to the globalization of domestic service. While the globalization of domestic service has been associated with a transnational female labour force, the transnational labour system has always been reconstituted as a new labour regime consistent with local particularity. In this article, I examine how Taiwanese employers discursively construct the otherness of their Filipino domestics. I argue that Taiwanese employers construct and naturalize the otherness of foreign domestics utilizing national identities, racial characteristics, and nationally based class difference. These differences, integral to the racialization of foreign domestics, are central not only to the persistence of their servitude at home but also to their social and political marginalization in the host society as a whole. The localization of a transnational labour force necessitates the examination of the contextual politics of difference. Rather than speaking of the universalized experience of foreign domestics, the contextual politics of difference provides a comparative framework for understanding not only the relational but also the contextual nature of identity construction. It demonstrates how difference is localized in the transnational system of care and how the localization of difference serves to reproduce social and global inequality.
A Report on Gender Discrimination in South Africa's 2002 Immigration Act: Masculinizing the Migrant
Authors: Dodson Belinda , Crush Jonathan
Published: September 2004

Changes in immigration policy and legislation have the power to shape and alter the gendering of migration in significant ways, and can have a dramatic effect on the lives and relationships of the men, women and families involved. In this paper, we examine the provisions of the new Immigration Act introduced in South Africa in 2002. The Act, which replaces the outdated Aliens Control Act of 1991, gives considerable cause for concern on gender grounds. Foremost, the Act entrenches a system of male-dominated regional labour migration that has its origins in the 19th-century discovery of gold and diamonds. The male bias in the work permit and other employment-based categories along with the limits to family reunification for those entering for work are likely in effect to discriminate against women to a greater extent than men. While similar gender concerns are common to most immigration policy regimes around the world, the particular circumstances of the South African case, where both skilled and unskilled migration streams are heavily male-dominated, makes them especially acute here. This paper contextualizes migration regimes in South Africa and examines in detail the likely implications of the new Immigration Act.
Method in Action and Method in Tool: A Stakeholder Perspective
Authors: Lundell Björn , Lings Brian
Published: September 2004

Tool support for information systems (IS) development can be considered from many perspectives, and it is not surprising that different stakeholders perceive such tools very differently. This can contribute on one side to poor selection processes and ineffective deployment of CASE, and on another to inappropriate tool development. In this paper, the relationship between CASE-tools and IS development methods is considered from three stakeholder perspectives: concept developer, IS developer and product developer. These perspectives, and the tensions between them, are characterised within a ‘stakeholder triangle’. Some of the major issues related to each tension are highlighted, and the triangle is then used to consider the importance, and implications for all stakeholders, of considering all tensions together. In particular, we suggest that the concept of ‘method in action’ be complemented by that of ‘method in tool’. We believe that these insights will contribute to the continuing debate on how to reduce adoption failures.
Genetic and phenotypic trends and parameters in reproduction, greasy fleece weight and liveweight in Merino lines divergently selected for multiple rearing ability
Authors: Cloete S. W. P. , Gilmour A. R. , Olivier J. J. , van Wyk J. B.
Published: September 2004

Genetic and phenotypic trends and parameters were estimated for reproduction, fleece weight and liveweight in a South African Merino population, divergently selected from 1986, either for (H line) or against (L line) maternal multiple rearing ability. Annual reproduction, ewe greasy fleece weight and pre-joining liveweight data were recorded on 809 Merino ewes, from 1986 to 2002. Phenotypic trends indicated divergence in reproduction traits between the H and L lines. The direct additive variance ratio (h2 ± s.e.) for day of lambing was 0.08 ± 0.02. Estimates of h2 for reproduction traits were: 0.10 ± 0.02 for number of lambs born per ewe; 0.04 ± 0.02 for number of lambs weaned per ewe; and 0.04 ± 0.02 for weight of lamb weaned per ewe, corrected for the gender of the lamb. Corresponding h2 estimates for annual production were 0.57 ± 0.06 for greasy fleece weight and 0.48 ± 0.06 for ewe liveweight at joining. Service sire only exerted a significant (P<0.05) effect on day of lambing, but it accounted for merely 2% of the overall phenotypic variation. Ewe permanent environment variance ratios (c2ewe) for the reproduction traits were: 0.07 ± 0.03 for number of lambs born per ewe; 0.11 ± 0.03 for number of lambs weaned per ewe; and 0.11 ± 0.03 for total weight of lamb weaned per ewe. Corresponding c2ewe estimates for annual production traits were 0.14 ± 0.05 for greasy fleece weight and 0.27 ± 0.06 for ewe joining weight. Genetic and ewe permanent environmental correlations between measures of reproduction exceeded 0.7. Genetic correlations of reproduction traits with greasy fleece weight were low and variable in sign. Genetic correlations of reproduction traits with ewe joining weight were positive and particularly high for weight of lamb weaned. Permanent environmental correlations of reproduction traits with greasy fleece weight and joining weight were generally low to moderate. Genetic trends for the H and L lines (derived from averaged direct breeding values within birth years) were divergent (P<0.01) for all reproduction traits. Expressed as percentage of the overall least squares means of the respective traits, breeding values in the H line increased annually, with 1.3% for lambs born per ewe, 1.5% for lambs weaned per ewe and by 1.8% for weight of lamb weaned per ewe. Corresponding trends in the L line were, respectively, –0.6%, –1.0% and –1.2% per year. Substantial genetic progress in annual lamb output was attainable, despite relatively small h2 estimates. This response was achieved without unfavourable genetic changes in wool and liveweight.
Increasing the economic benefits from agricultural research: the case of enhancing the diffusion of a pasture weed technology
Authors: Vere D. T. , Jones R. E. , Dowling P. M.
Published: September 2004

The process of enhancing the diffusion of a new technology attempts to shorten the time between the completion and adoption of an agricultural research programme, as well as to increase the overall level of adoption. The economic benefits of introducing a new technology are influenced by the technology development lag, the adoption lag and the maximum, or ceiling, level of adoption. Technology diffusion embodies these issues and concerns the uptake of a new technology across a population of potential adopters. Diffusion enhancement is now considered to be a desirable component of pasture research programmes in Australia. This paper evaluates the economic benefits of enhancing the diffusion process for new technology in the management of Vulpia, which is a prominent annual grass weed of Australian temperate pastures. Differences in economic benefits were calculated for a range of scenarios, by varying the values of the main elements of the diffusion process relative to those of a base scenario which represented the most optimistic adoption expectations for the technology. The discounted total benefits to the Australian wool industry, calculated for a 15-year period from reducing Vulpia in temperate pastures, were between A$31.9 million and A$287.3 million, according to differences in the pasture's Vulpia content. While the 2 main time components of the diffusion process both had strong effects on the potential benefits, the technology lag had a much larger influence than the adoption lag. This result emphasises the importance of agricultural research programmes that are able to quickly diffuse such technologies to the potential adopters.
Effects of supplement grain type and level of feeding on the milk production of early-lactation Holstein - Friesian cows grazing temperate and tropical pastures
Authors: Granzin B. C.
Published: September 2004

Two experiments were undertaken to examine the effects of supplement grain type (barley v. maize) and level of feeding [4.5 v. 8.1 kg dry matter (DM)/cow.day] on the milk production, nutrient intake and rumen fermentation of cows grazing swards of biennial ryegrass (Lolium multiflorum cv. Concord), prairie grass (Bromus willdenowii cv. Matua) (expt 1) or kikuyu (Pennisetum clandestinum cv. Common) (expt 2). There were no interactions (P>0.05) between grain type and level of feeding (G × L) on milk production, liveweight change or condition score in either experiment.
When the main effects were examined, feeding maize as opposed to barley resulted in higher milk protein concentrations (P = 0.001) in both experiments (2.96 v. 2.83% and 2.91 v. 2.71% for expts 1 and 2, respectively), higher milk fat concentration (P = 0.001; 3.85 v. 3.36%) and daily milk fat yield per cow (P = 0.029; 875 v. 791 g) in experiment 1, and higher daily yield (P = 0.004) of milk protein in experiment 2 (618 v. 578 g). In both experiments, feeding increased supplement resulted in higher (P<0.05) daily yields per cow of milk (24.1 v. 22.0 L and 23.6 v. 20.1 L for expts 1 and 2, respectively) and milk protein (703 v. 637 g and 646 v. 550 g for expts 1 and 2, respectively), and lower (P<0.05) milk fat concentrations (3.46 v. 3.76% and 3.25 v. 3.57% for expts 1 and 2, respectively). In both experiments, there were no G × L interactions (P>0.05) on pasture intake, neutral detergent fibre digestibility or rumen concentrations of ammonia or volatile fatty acids. There were G × L interactions on organic matter digestibility (P = 0.019) in experiment 1 and on starch digestibility (P = 0.003) in experiment 2, with cows fed 4.5 kg DM/day of barley having higher organic matter digestibility, and cows fed either level of barley having higher starch digestibility. In both experiments, feeding more supplement reduced (P>0.05) daily pasture intake per cow (13.3 v. 11.3 kg DM and 9.9 v. 8.3 kg DM for expts 1 and 2, respectively). Feeding barley rather than maize caused higher starch digestibility (P = 0.006) in experiment 1 (93.0 v. 89.8%), and higher organic matter digestibility (P = 0.021) and neutral detergent fibre digestibility (P = 0.009) in experiment 2 (70.8 v. 69.3% and 62.9 v. 59.7%, for organic matter digestibility and neutral detergent fibre digestibility, respectively). Feeding maize rather than barley reduced (P = 0.034) rumen molar proportion of butyrate (16.1 v. 17.6 mol %) in experiment 1. These experiments show that feeding supplements based on maize, as opposed to barley can: increase the milk fat concentration and yield of cows grazing temperate pastures; increase the milk protein yield of cows grazing tropical pastures; and increase the milk protein concentration of cows grazing either temperate or tropical pastures.
Seasonal variation in muscle glycogen in beef steers
Authors: Knee B. W. , Cummins L. J. , Walker P. , Warner R.
Published: September 2004

Dark-cutting in beef carcasses is a quality and economic problem for the grass-fed beef industry in Australia, with ~10% of carcasses graded as dark-cutting. Dark-cutting results from low muscle glycogen levels at the time of slaughter. An experiment was designed to examine the relationship between season and muscle glycogen levels for cattle at pasture. Sixty steers were allocated to 2 stocking rate treatments, low and high (1.5 and 2.5 steers/ha, respectively) with 3 replicates for each treatment and grazed in 6 separate paddocks. Monthly samples of the M. semimembranosus (SM) and M. semitendinosus (ST) were taken by biopsy from all cattle and analysed for glycogen and lactate content.
Significant differences in muscle glycogen were found between seasons. Average muscle glycogen levels for autumn, winter, spring and summer were 1.24, 1.00, 1.15 and 0.82 mg/g SM and 0.85, 0.91, 1.05 and 0.76 mg/g ST, respectively. The seasonal effects on muscle glycogen were not influenced by stocking rate, but it is postulated that they were influenced by nutrition, with the peak in muscle glycogen level generally coinciding with the peak in pasture quantity and quality in spring.
Correlation of morphological traits with molecular markers in radish (Raphanus sativus)
Authors: Pradhan A. , Yan G. , Plummer J. A.
Published: September 2004

Radish (Raphanus sativus L.) is an important vegetable crop in Asia. Lack of uniformity in the crop at harvest is due to genetic variability and environmental conditions. Molecular markers associated with morphological traits of seed and seedlings were identified. Seed (100) of radish cvv. Fire Ball and Long White Chinese from Australia and Mino Early, Pyuthane Red, Tokinasi, White Neck and 40 Days from Nepal. The seed was germinated between paper (20°C, 6 days) and seedlings were grown in pots under glasshouse conditions (20°C, further 3 weeks). Morphological characters were measured in seed and seedlings at 6 days and 4 weeks after germination. Deoxyribonucleic acid was extracted from selected samples and Random Amplified Polymorphic DNA (RAPD) markers were identified using 10 primers. Multivariate analysis based on principle coordinates analysis was used to correlate morphological traits with molecular markers within and across cultivars. Several markers associated with high or low seed weight, germination proportion, seedling length and fresh weight were identified. This new method for identifying potential RAPD markers may be useful for marker assisted breeding and selection of improved radish varieties.
Phalaris persistence under rotational grazing on a highly acidic soil on the south-west slopes of New South Wales
Authors: Li G. D. , Helyar K. R. , Conyers M. K. , Cullis B. R. , Poile G. J. , Knight P. G.
Published: September 2004

Phalaris (Phalaris aquatica L.)-based pastures were established with and without lime in 1992 as a part of a long-term pasture–crop rotation experiment (Managing Acid Soils Through Efficient Rotations). Pre- and post-grazing pasture dry matter, phalaris basal cover and proportion of phalaris in sward were measured since 1992. In general, phalaris persisted well and its productivity was high on the highly acidic soil studied in the current experiment, and this was improved on the limed treatment. After establishment in 1992, the average proportion of phalaris in spring 2001 was 32.1% in the limed treatment and 15.6% in the unlimed treatment. Basal cover at the end of summer 2002 was 4.5% and 2.0% for the limed and unlimed treatments, respectively. The results from the current experiment showed that subsurface acidity (low pHCa and high exchangeable aluminium percentage in the 10–30 cm soil depth) had significant impacts on phalaris persistence. It is concluded that subsurface pH was one of the major constraints for the persistence of phalaris. The long-term management of soil acidity should aim to eliminate the exchangeable aluminium from the soil profile by maintaining a high pHCa (5.5 or above) in the 0–10 cm soil depth. Rainfall during growing season had no direct effect on phalaris persistence. Nevertheless, feed scarcity in dry years due to moisture stress often exacerbated grazing pressure on phalaris, which may affect the phalaris persistence indirectly.
It is the grazing management in autumn and summer that had significant effects on phalaris persistence. It is suggested that rotational grazing plus strategic rest if possible in autumn could prolong the life of phalaris-based pastures. Repeated heavy grazing should be avoided during summer, particularly after light to moderate summer rainfall events have stimulated sprouting.
Rooting of 'GF677' (almond × peach hybrid) hardwood cuttings in relation to hydrogen hyperoxide, moisture content, oxygen concentration, temperature and pH of substrate
Authors: Tsipouridis C. , Thomidis T.
Published: September 2004

In this study, the influence of water content, temperature, oxygen concentration and pH of perlite substrate and H2O2 treatments on the rooting percentage of GF677 hardwood cuttings was examined. The best moisture level was 100 mL in 500 mL perlite; this resulted in 100% rooting. The observations showed that even pure O2 did not reduce callusing or, possibly, rooting and it gave similar results as 21% O2. There was no indication of a promotory effect. No rooting or callusing was observed in N, 5% CO2 or 5% O2 treatments. There were significant differences in the responses to temperature and pH levels. The best temperature was 29°C, while the best pH levels were between 3 and 5. Cuttings in media with higher pH levels (7–8) rooted less successfully. The results also showed that H2O2 possibly had an effect on the rooting percentage of cuttings.
The effects of site and season on the yield and nutritive value of cultivars and half-sib families of perennial ryegrass (Lolium perenne)
Authors: Smith K. F. , Simpson R. J. , Oram R. N.
Published: September 2004

The effects of site and season on the nutritive value of 16 perennial ryegrass cultivars and 60 half-sib families were assessed at 2 locations in South West Victoria. Crude protein, water-soluble carbohydrates, neutral detergent fibre and in vitro digestibility were measured on vegetative herbage, harvested in either autumn or spring. While no heritable genetic variation for nutritive value parameters was detected in this set of families, consistent differences in the nutritive value of cultivars were measured across sites and seasons. The cultivars Yatsyn1 and Ellett were consistently high in both water-soluble carbohydrates and in vitro digestibility. The differences in mean nutritive value between high and low ranking cultivars were ~40 g/kg water-soluble carbohydrates and 3–5% in vitro digestibility. These consistent differences in forage quality demonstrate the value of measuring forage quality during cultivar evaluation. The identification of cultivars with improved nutritive value will also facilitate the crossing of the alleles that confer this improvement into other genetic backgrounds.