bluuebunny/crossref_metadata_2025 huggingface dataset:
Interannual changes in recruitment of the Atlantic salmon (Salmo salar) population in the River Oir (Lower Normandy, France): relationships with spawners and in-stream habitat
Authors: Baglinière Jean-Luc , Marchand Frédéric , Vauclin Vincent
Published: May 2005

Since 1985, the dynamics of the Atlantic salmon (Salmo salar) population in the River Oir, a spawning tributary of the River Sélune (Lower Normandy, France), have been studied from a data set of parr density and the number and the age structure of migrating fish (smolts and adults). Parr densities (1.5–17.4 per 100 m2) and smolt production (0.25–9.2 per 100 m2) varied considerably from year to year. Migrating juveniles were mainly 1 year old. Abundance of parr and smolts was strongly correlated with 0+ densities. Egg-to-smolt survival rates were highly variable year on year (0.044–1.07%). During the juvenile freshwater phase, mortality was highest between the egg and the 0+ stage (97.5–99.9%). The fluctuations in abundance of juvenile salmon appear to be linked to the number and distribution of spawners within the stream during spawning, and also to the amount of silt deposition on the spawning beds. As a result, mortality was highest during the under-gravel phase, and the mean survival rate from egg to smolt was much lower than in rivers less impacted by human activities. Therefore, during the study period, the low production of smolts during some years might lead to a low renewal rate of the salmon population.
Expression and activation of peroxisome proliferator‐activated receptors in growth plate chondrocytes
Authors: Shao Yvonne Y. , Wang Lai , Hicks David G. , Tarr Shannon , Ballock R. Tracy
Published: May 2005

Peroxisome proliferator‐activated receptor γ (PPAR‐γ) is a nuclear hormone receptor that is involved in a wide range of cellular processes. Although it is known that PPAR‐γ plays an important role in cell cycle control, inflammation, apoptotic cell death, and other cellular processes, the role of PPAR‐γ in the normal and pathological function of growth plate chondrocytes has not been investigated. The purpose of this study was to determine if PPARs are expressed in growth plate chondrocytes and to describe the biological effect of PPAR activation in these cells. The results demonstrate the presence of three PPAR isoforms (α, δ, and γ) in growth plate cartilage. Activation of PPAR‐γ by ciglitazone in growth plate chondrocytes inhibits T3 induced terminal differentiation and promotes apoptosis through increased levels of caspase 3/7 activity and decreased expression of the anti‐apoptotic protein Bcl‐2. © 2005 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
In defence of mystery: a reply to Dale Tuggy
Authors: ANDERSON JAMES
Published: May 2005

In a recent article, Dale Tuggy argues that the two most favoured approaches to explicating the doctrine of the Trinity, Social Trinitarianism and Latin Trinitarianism, are unsatisfactory on either logical or biblical grounds. Moreover, he contends that appealing to ‘mystery’ in the face of apparent contradiction is rationally and theologically unacceptable. I raise some critical questions about Tuggy's assessment of the most relevant biblical data, before defending against his objections the rationality of an appeal to mystery in the face of theological paradox.
The hiddenness argument revisited (I)
Authors: SCHELLENBERG J. L.
Published: May 2005

More than a few philosophers have sought to answer the atheistic argument from reasonable non-belief (a.k.a. the argument from divine hiddenness or the hiddenness argument) presented in my 1993 book Divine Hiddenness and Human Reason. In this first of two essays in response, I focus on objections sharing the defect – sometimes well-hidden – of irrelevance, using their shortcomings to highlight important features of the argument that are commonly overlooked.
Do religious beliefs aim at the truth?
Authors: SCOTT MICHAEL
Published: May 2005

This paper evaluates Brian Zamulinski's argument from considerations of relative likelihood for preferring a ‘religion-as-fiction’ hypothesis to metaphysical realism. The paper finds that the argument fails to consider numerous variant hypotheses, and that the ‘religion-as-fiction’ hypothesis is poorly formulated. It is concluded that an argument from likelihood about the status of religious belief will not, in the way Zamulinski constructs it, give support to a hypothesis unless supplemented by an estimate of its probability. Moreover, once probability is taken into account, the ‘religion-as-fiction’ hypothesis looks very weak.
Working Memory, its Executive Functions, and the Emergence of Modern Thinking
Authors: Coolidge Frederick L. , Wynn Thomas
Published: May 2005

This article examines the possible origins of modern thinking by evaluating the cognitive models of working memory, executive functions and their interrelationship. We propose that a genetic mutation affected neural networks in the prefrontal cortex approximately 60,000 to 130,000 years ago. Our review of cognitive and archaeological evidence yields two possibilities: either it was non-domain specific, affecting general working memory capacity and its executive functions, or the mutation was domain-specific, affecting phonological storage capacity. We discuss the sequelae of these possibilities for modernity, including language enhancement, greater reasoning, planning, and modelling abilities, and increases in fluid/general intelligence.
Body Metamorphosis and Animality: Volatile Bodies and Boulder Artworks from Lepenski Vir
Authors: Borić Dušan
Published: May 2005

This article discusses the notion of body metamorphosis as a theory of phenomenal change by examining carved representational and ‘aniconic’ boulders from Lepenski Vir and other Meso-Neolithic sites in the Danube Gorges. The voluminous size of the boulders at Lepenski Vir, the way in which they occupy the three-dimensional space within buildings and around hearths, and the carvings over their surfaces suggest that they were understood as volatile bodies, undergoing continuous metamorphoses. The relationship between the seasonal recurrence of the Danube's migratory fish and these boulders is explored through the notion of animality. These boulders indicate prescribed stages of life-cycle metamorphosis that affected inextricably-linked realms of human and animal worlds. Prescribed stages of social embodiment at Lepenski Vir are discerned by looking at the archaeological context of representational boulders that sometimes directly commemorate particular deceased individuals. The possibility that boulder artworks acted as sacred heirlooms of particular buildings is connected to the social efficacy they might have acquired.
Historicizing the Spiritual: Bu Shell Arrangements on the Island of Badu, Torres Strait
Authors: David Bruno , Crouch Joe , Zoppi Ugo
Published: May 2005

Bu (Syrinx aruanus) shell arrangements are often found in ritual sites across Torres Strait. The position of such sites within Indigenous cosmologies has been ethnographically documented for the nineteenth and twentieth centuries. This article historicizes Indigenous spiritscapes by tracking back in time the history of this particular material expression of spiritual belief in Western Torres Strait. We argue that the last c. 400 years saw major shifts in ritual engagements with seascapes in Western Torres Straits. These transformations may have been Indigenous responses to the traumatic events of early contact with European seafarers, in particular the earliest Spanish sailors of 1606.
The Water Supply and Distribution System of the Nabataean City of Petra (Jordan), 300 bc– ad 300
Authors: Ortloff Charles R.
Published: May 2005

The water supply and distribution system of the Nabataean city of Petra in southwestern Jordan has been explored and mapped. Analysis of the system indicates exploitation of all possible water resources using management techniques that balance reservoir storage capacity with continuous flow pipeline systems to maintain a constant water supply throughout the year. Nabataean Petra was founded c. 300 bc; urban development progressed with later Roman administration of the city starting at ad 106; Byzantine occupation continued to the seventh century ad. Trade networks that extended throughout much of the ancient Near East and Mediterranean world intersected at Petra, and brought not only strategic and economic prominence, but also impetus to develop water resources fully to sustain demands of increasing population and city elaboration. City development was influenced by artistic, cultural and technological borrowings from Seleucid, Syro-Phoenician, Greek and Roman civilizations; the Petra water-distribution system included hydraulic technologies derived from these contacts as well as original technical innovations that helped to maintain the high living standard of city dwellers throughout the centuries. Analysis of the Nabataean water network indicates design criteria that promote stable flows and use sequential particle-settling basins to purify potable water supplies. They also promote open channel flows within piping at critical (maximum) flow rates that avoid leakage associated with pressurized systems and have the design function to match the spring supply rate to the maximum carrying capacity of a pipeline. This demonstration of engineering capability indicates a high degree of cognitive skill in solving complex hydraulic problems to ensure a stable water supply and may be posited as a key reason behind the many centuries of flourishing city life.
PREVENTION AND TREATMENT OF VENOUS THROMBOEMBOLISM IN HIGH RISK SITUATIONS IN PREGNANCY
Authors: McLEOD ANNE G , ELLIS CAMERON
Published: May 2005

Venous thromboembolism (VTE) is a leading cause of maternal mortality in the western developed world. VTE may present as deep vein thrombosis (DVT) or pulmonary embolism (PE) but if untreated can result in fatal PE. Although fatal PE is clearly the most significant consequence of VTE in pregnancy, DVT also often leads to morbidity related to the development of post-thrombotic syndrome (PTS). Pregnancy is an independent risk factor for VTE and the risk of VTE is 4–10 fold higher in pregnant women than in non-pregnant women of similar age. The puerperium represents a time of even higher risk. It is clear that many additional high-risk situations in pregnancy lower the threshold for thrombosis and warrant measures to prevent VTE and its complications. Risk factors for pregnancy-related VTE may be inherited or acquired. Acquired risk factors may be specifically related to the pregnancy or may have developed prior to pregnancy. Well-documented risk factors for pregnancy-related VTE include delivery by Caesarean section, previous VTE, and inherited or acquired thrombophilia. Other risk factors that have been identified include obesity, multiparity, multiple gestation, pre-eclampsia and medical conditions, such as sickle cell disease, that predispose to VTE. Our ability to diagnose VTE overall is poor as presenting signs and symptoms are extremely varied and unreliable. This is further complicated in pregnancy where signs and symptoms suggestive of VTE are common and invasive testing is more complicated. It is essential that physicians be vigilant in monitoring patients for the development of VTE and maintain a low threshold for considering thromboprophylaxis. Guidelines have recently been published by several medical societies to help with these difficult decisions. In this review the risk factors for the development of VTE in pregnancy will be discussed and guidelines for risk assessment presented. Management of patients who develop VTE in pregnancy is also outlined.
COMBINED SPINAL EPIDURAL ANALGESIA IN LABOUR
Authors: LEWIS MARGO , CALTHORPE NICOLA
Published: May 2005

The combined spinal epidural (CSE) as an anaesthetic technique for providing analgesia for labour and anaesthesia for operative delivery has gained in popularity over the last ten years. Essentially the CSE consists of identification of the epidural space and insertion of an epidural catheter plus the initial intentional placement of an intrathecal dose of opioid, local anaesthetic or both, all as a single procedure. Theoretically the technique combines the advantages of the speed of onset and the reliability of block achieved by subarachnoid anaesthesia with the flexibility provided by the presence of an epidural catheter and avoids their individual disadvantages. The complications that may be encountered are those attributable to subarachnoid and epidural anaesthesia individually but some are unique to the CSE technique. The CSE technique is also applicable to other situations in obstetrics where a block is initiated by subarachnoid anaesthesia and its continuation is facilitated by the presence of an epidural catheter, either to maintain anaesthesia for prolonged procedures or for post operative pain control. The CSE's popularity has been ensured by the fact that it has allowed rapid onset analgesia with minimal motor blockade to be provided routinely for mothers in labour.
Attachment to stainless steel by Mir Space Station bacteria growing under modeled reduced gravity at varying nutrient concentrations
Authors: Baker P. W. , Leff L. G.
Published: May 2005

Four bacterial isolates (Chryseobacterium sp., Pseudomonas fluorescens and two Stenotrophomonas maltophilia isolates) originally isolated from the water system aboard the Mir Space Station were grown in two concentrations of nutrient broth under modeled reduced gravity using clinorotation. Sampling was performed over a 7 day period and planktonic cells were enumerated using 4′,6-diamidino-2-phenylindole (DAPI), while those attached to stainless steel were enumerated using the LIVE/DEAD® BacLight™ kit and DAPI. On some of the sampling days for all the isolates, planktonic cell counts were higher under modeled reduced gravity as compared with the normal gravity controls. In contrast, the number of cells of P. fluorescens and one S. maltophilia isolate attached to the stainless steel disks was higher under modeled reduced gravity as compared with normal gravity, whereas no such differences were observed for Chryseobacterium sp. and the other S. maltophilia isolate. Differences in motility among isolates appeared to influence the growth of planktonic cells under modeled reduced gravity but did not appear to be related to biofilm formation.
Investigation into biofilms in a local drinking water distribution system
Authors: Hu J. Y. , Yu B. , Feng Y. Y. , Tan X. L. , Ong S. L. , Ng W. J. , Hoe W. C.
Published: May 2005

Biofilm growth within a water distribution system could lead to operational problems such as pipe corrosion, water quality deterioration and other undesirable impacts in water distribution systems. With the high ambient temperatures experienced in Singapore, the operating environment in water distribution systems is expected to be more conducive to biofilm development. We have recently conducted a survey on biofilms potentially present in a local water distribution system.

The survey results indicated that residual chlorine (±standard deviation) decreased from 1.49±0.61 mg/l (water plant outlets) to 0.82±0.21 mg/l (block pipes) or 0.18±0.06 mg/l (unit pipes), respectively. Consumed chlorine, instead of residual chlorine, was found to be correlated with biofilm bacterial population. Assimilable organic carbon (AOC) level was 160±66 μg acetate C/l, and AOC:PO4-P:NO3-N was about 8:13:1. Carbon source seemed to be the limiting nutrient for bacterial growth. The concentration of iron increased from <0.04 mg/l (water plant outlets) to 0.22±0.10 mg/l (all sites). All samples showed negative results in a coliform test. The average heterotrophic plate count (HPC) for the suspended bacteria was 20 colony-forming units (c.f.u.)/ml (2 days, 35 °C) or 290 c.f.u./ml (8 days, 35 °C). The average HPC for the biofilm bacteria was 6500 c.f.u./cm2 (2 days, 35 °C) or 29000 c.f.u./cm2 (8 days, 35 °C). High HPC values in samples B2a, B2b and B3a (representing biofilm samples at site 2 from block/unit pipes and biofilm samples at site 3 from block pipes, respectively) illustrated that the relevant sample sites had a higher probaboility of biofilm growth.
Adhesion and biofilm formation of Candida albicans on native and Pluronic-treated polystyrene
Authors: Wesenberg-Ward K. E. , Tyler B. J. , Sears J. T.
Published: May 2005

Candida albicans forms part of the normal human flora whose growth is usually restricted by the normal flora bacteria and the host's immune system. It is an opportunistic fungal pathogen that causes infections in immunocompromised individuals, mechanical trauma victims and iatrogenic patients. Candida albicans can ingress the human host by adhering to a plastic surface (i.e. prosthetic devices, catheters, artificial organs, etc.) that is subsequently implanted, and forms a protective biofilm that provides a continuous reservoir of yeast to be hematogenously dispersed. In order for the medical profession to battle device-related infections, initial adhesion and biofilm formation of C. albicans needs to be better understood. There has been some skepticism as to whether the initial adhesion events bear any relationship to subsequent biofilm formation. Thus, to better comprehend the relationship between the initial adhesion rates and growth rate and biofilm formation, these events were studied on two different, well-defined culture surfaces, native polystyrene and Pluronic F127-conditioned polystyrene. The adhesion studies determined that Pluronic F127 adsorption dramatically reduced the adhesion of C. albicans to polystyrene. The biofilm growth studies, analyzed by confocal scanning laser microscopy, revealed that Pluronic F127 decreased the biofilm surface coverage, cluster group size, thickness and the presence of hyphal elements over the untreated polystyrene. These findings indicate that the effect of a material's surface chemistry on the initial adhesion process has a direct influence on subsequent biofilm formation.
TES spectroscopic identification of a region of persistent water ice clouds on the flanks of Arsia Mons Volcano, Mars
Authors: Noe Dobrea E. Z. , Bell J. F.
Published: May 2005

As part of a search for small‐scale spectrally anomalous regions within the Mars Global Surveyor Thermal Emission Spectrometer (MGS/TES) data set, we have identified a region ∼100 km in diameter on the southwest flanks of the volcano Arsia Mons that exhibits remarkable and persistent water ice cloud cover. High‐opacity clouds (by Martian standards) occur in this region in all of the 400 TES spectra covering this area, regardless of season, as well as in all of the MGS Wide‐Angle camera images of this same region. We have also found evidence for similar persistent cloudiness at other local solar times of day in this region based on Hubble Space Telescope UV imaging. Modeling of the TES spectra identifies the clouds as water ice and reveals average IR cloud optical depths near 0.5 and typical cloud particle sizes of ∼3 μm. The presence of persistent cloudiness in this area, even during the relatively warm and cloud‐free season near perihelion, may indicate unique local circulation processes, perhaps related to orographic effects or the interaction between the global circulation and the Tharsis region in general. Our analysis also demonstrates that through careful modeling it is possible to extend the search for unique spectral features in the TES data far into the wings of the strong 15‐μm CO2 band.
Sedimentary rocks as sources of ancient organic carbon to the ocean: An investigation through Δ14C and δ13C signatures of organic compound classes
Authors: Komada Tomoko , Druffel Ellen R. M. , Hwang Jeomshik
Published: May 2005

Chemical and isotopic variability of particulate organic carbon (POC) was examined in samples from the Santa Clara River watershed and adjacent shelf to investigate the processing of fossil POC derived from bedrock. The Santa Clara is a small coastal river that drains mountainous terrain in southern California, United States. Organic carbon in shale, river suspended sediment, and coastal marine sediment was separated into three operationally defined organic compound classes: total extractable lipids, acid hydrolyzable material, and the nonhydrolyzable residue. In all samples, the nonhydrolyzable fraction was dominant (∼50% of POC), while lipids and acid hydrolyzable moieties were relatively minor (≤22 and ≤13%, respectively). The Δ14C and δ13C signatures of the isolated fractions varied dramatically, not only across different sample types, but also for a given sample. At the shale exposure, low Δ14C values (<−760‰) indicated dominance of ancient C in all three organic compound classes. In downstream samples, the extractable lipids displayed the lowest Δ14C values (<−500‰), while the acid hydrolyzable fraction was predominantly modern (Δ14C > −30‰). The nonhydrolyzable fraction displayed intermediate Δ14C values (<−190‰) that increased steadily downstream with decreasing δ13C values (−22.2 to −25.0‰), possibly from mixing of shale and surface soil POC. Our results indicate that most of the fossil POC discharged by the Santa Clara is composed of non‐acid hydrolyzable material, but its elusive molecular structure and marine‐like δ13C signature may render its detection in the ocean difficult. In contrast, fossil lipids may be more amenable to detection if their resistant components (e.g., asphaltic material) are unique to crustal sources.
A movable trigger: Fossil fuel CO2 and the onset of the next glaciation
Authors: Archer David , Ganopolski Andrey
Published: May 2005

The initiation of northern hemisphere ice sheets in the last 800 kyr appears to be closely controlled by minima in summer insolation forcing at 65°N. Beginning from an initial typical interglacial pCO2 of 280 ppm, the CLIMBER‐2 model initiates an ice sheet in the Northern Hemisphere when insolation drops 0.7 σ (standard deviation) or 15 W/m2 below the mean. This same value is required to explain the history of climate using an orbitally driven conceptual model based on insolation and ice volume thresholds (Paillard, 1998). When the initial baseline pCO2 is raised in CLIMBER‐2, a deeper minimum in summertime insolation is required to nucleate an ice sheet. Carbon cycle models indicate that ∼25% of CO2 from fossil fuel combustion will remain in the atmosphere for thousands of years, and ∼7% will remain beyond one hundred thousand years (Archer, 2005). We predict that a carbon release from fossil fuels or methane hydrate deposits of 5000 Gton C could prevent glaciation for the next 500,000 years, until after not one but two 400 kyr cycle eccentricity minima. The duration and intensity of the projected interglacial period are longer than have been seen in the last 2.6 million years.
Amplified carbon release from vast West Siberian peatlands by 2100
Authors: Frey Karen E. , Smith Laurence C.
Published: May 2005

Extensive new data from previously unstudied Siberian streams and rivers suggest that mobilization of currently frozen, high‐latitude soil carbon is likely over the next century in response to predicted Arctic warming. We present dissolved organic carbon (DOC) measurements from ninety‐six watersheds in West Siberia, a region that contains the world's largest stores of peat carbon, exports massive volumes of freshwater and DOC to the Arctic Ocean, and is warming faster than the Arctic as a whole. The sample sites span ∼106 km2 over a large climatic gradient (∼55–68°N), providing data on a much broader spatial scale than previous studies and for the first time explicitly examining stream DOC in permafrost peatland environments. Our results show that cold, permafrost‐influenced watersheds release little DOC to streams, regardless of the extent of peatland cover. However, we find considerably higher concentrations in warm, permafrost‐free watersheds, rising sharply as a function of peatland cover. The two regimes are demarcated by the position of the −2°C mean annual air temperature (MAAT) isotherm, which is also approximately coincident with the permafrost limit. Climate model simulations for the next century predict near‐doubling of West Siberian land surface areas with a MAAT warmer than −2°C, suggesting up to ∼700% increases in stream DOC concentrations and ∼2.7–4.3 Tg yr−1 (∼29–46%) increases in DOC flux to the Arctic Ocean.
Continental liquid water cloud variability and its parameterization using Atmospheric Radiation Measurement data
Authors: Kim Byung‐Gon , Klein Stephen A. , Norris Joel R.
Published: May 2005

Liquid water path (LWP) variability at scales ranging from roughly 200 m to 20 km in continental boundary layer clouds is investigated using ground‐based remote sensing at the Oklahoma site of the Atmospheric Radiation Measurement (ARM) program. Twelve episodes from the years of 1999 to 2001 are selected corresponding to conditions of overcast, liquid water single‐layered cloud. In contrast to previous studies of marine boundary layer clouds, variability in cloud‐top height in these clouds is comparable to that of cloud base, and most continental clouds appear to be subadiabatic. In agreement with previous studies of marine boundary layer clouds, variations in LWP are well related to the variations in cloud thickness. LWP variability exhibits significantly negative correlation with the static stability of the inversion near cloud top; larger cloud variability is associated with less stable inversions. A previously developed parameterization of LWP variability is extended to account for the differing conditions of continental clouds. The relationship between fluctuations in LWP and cloud thickness suggests that cloud parameterizations treating variations in LWP at these scales should include the effects of subgrid‐scale fluctuations in cloud thickness. One such treatment is proposed within the context of a statistical cloud scheme.
New studies of SAGE II and HALOE ozone profile and long‐term change comparisons
Authors: Nazaryan Hovakim , McCormick M. Patrick , Russell James M.
Published: May 2005

A comparison of the ozone data sets from the Stratospheric Aerosol and Gas Experiment II (SAGE II) (version 6.1) and the Halogen Occultation Experiment (HALOE) (version 19) is discussed for the period 1991–2000. A more accurate approach than those used in previous studies is applied for the comparisons, which takes into account measurement uncertainties and produces improved results. This approach gave closer agreement between the two measurement systems in terms of absolute values and differences in long‐term changes, that is, trends determined from each data set. In our work the analysis of weighted mean differences in coincident measurements by the two experiments shows approximately a 5% bias over the altitude range 20.5–50.5 km in the majority of latitude bands, with some exceptions. The SAGE II values are typically larger than the HALOE values. We calculate the slopes of the time series of differences between the two instruments and analyze ozone trends. This analysis, which covers a longer time period than was studied before, indicates little to no long‐term drift in either measurement system. The improved trend analysis methods used in this study show more statistically significant trends than were reported before. Ozone trend comparisons from these instruments show trend differences on the order of less than 0.3% per year in a majority of latitude bands at 25, 35, 45, and 55 km altitudes. Those differences are smaller than reported in other studies, thus revealing remarkable agreement between SAGE II and HALOE trend results.
Effect of climate sensitivity on the response to volcanic forcing
Authors: Wigley T. M. L. , Ammann C. M. , Santer B. D. , Raper S. C. B.
Published: May 2005

The results from 16 coupled atmosphere/ocean general circulation model (AOGCM) simulations are used to reduce internally generated noise and to obtain an improved estimate of the underlying response of 20th century global mean temperature to volcanic forcing. An upwelling diffusion energy balance model (UD EBM) with the same forcing and the same climate sensitivity as the AOGCM is then used to emulate the AOGCM results. The UD EBM and AOGCM results are in very close agreement, justifying the use of the UD EBM to determine the volcanic response for different climate sensitivities. The maximum cooling for any given eruption is shown to depend approximately on the climate sensitivity raised to power 0.37. After the maximum cooling for low‐latitude eruptions the temperature relaxes back toward the initial state with an e‐folding time of 29–43 months for sensitivities of 1–4°C equilibrium warming for CO2 doubling. Comparisons of observed and modeled coolings after the eruptions of Agung, El Chichón, and Pinatubo give implied climate sensitivities that are consistent with the Intergovernmental Panel on Climate Change (IPCC) range of 1.5–4.5°C. The cooling associated with Pinatubo appears to require a sensitivity above the IPCC lower bound of 1.5°C, and none of the observed eruption responses rules out a sensitivity above 4.5°C.
Stability and exchange of subsurface ice on Mars
Authors: Schorghofer Norbert , Aharonson Oded
Published: May 2005

We seek a better understanding of the distribution of subsurface ice on Mars, based on the physical processes governing the exchange of vapor between the atmosphere and the subsurface. Ground ice is expected down to ∼49° latitude and lower latitudes at poleward facing slopes. The diffusivity of the regolith also leads to seasonal accumulation of atmospherically derived frost at latitudes poleward of ∼30°. The burial depths and zonally averaged boundaries of subsurface ice observed from neutron emission are consistent with model predictions for ground ice in equilibrium with the observed abundance of atmospheric water vapor. Longitudinal variations in ice distribution are due mainly to thermal inertia and are more pronounced in the observations than in the model. These relations support the notion that the ground ice has at least partially adjusted to the atmospheric water vapor content or is atmospherically derived. Changes in albedo can rapidly alter the equilibrium depth to the ice, creating sources or sinks of atmospheric H2O while the ground ice is continuously evolving toward a changing equilibrium. At steady state humidity and temperature oscillations, the net flux of vapor is uninhibited by adsorption. The occurrence of temporary frost is characterized by the isosteric enthalpy of adsorption.
Ionospheric irregularity characteristics from quasiperiodic structure in the radio wave scintillation
Authors: Chen K. Y. , Su S. Y. , Liu C. H. , Basu S.
Published: May 2005

Quasiperiodic (QP) diffraction pattern in scintillation patches has been known to highly correlate with the edge structures of a plasma bubble (Franke et al., 1984). A new time‐frequency analysis method of Hilbert‐Huang transform (HHT) has been applied to analyze the scintillation data taken at Ascension Island to understand the characteristics of corresponding ionosphere irregularities. The HHT method enables us to extract the quasiperiodic diffraction signals embedded inside the scintillation data and to obtain the characteristics of such diffraction signals. The cross correlation of the two sets of diffraction signals received by two stations at each end of Ascension Island indicates that the density irregularity pattern that causes the diffraction pattern should have an eastward drift velocity of ∼130 m/s. The HHT analysis of the instantaneous frequency in the QP diffraction patterns also reveals some frequency shifts in their peak frequencies. For the QP diffraction pattern caused by the leading edge of the large density gradient at the east wall of a structured bubble, an ascending note in the peak frequency is observed, and for the trailing edge a descending note is observed. The linear change in the transient of the peak frequency in the QP diffraction pattern is consistent with the theory and the simulation result of Franke et al. Estimate of the slope in the transient frequency provides us the information that allows us to identify the locations of plasma walls, and the east‐west scale of the irregularity can be estimated. In our case we obtain about 24 km in the east‐west scale. Furthermore, the height location of density irregularities that cause the diffraction pattern is estimated to be between 310 and 330 km, that is, around the F peak during observation.
Influence of sediment storage on downstream delivery of contaminated sediment
Authors: Malmon Daniel V. , Reneau Steven L. , Dunne Thomas , Katzman Danny , Drakos Paul G.
Published: May 2005

Sediment storage in alluvial valleys can strongly modulate the downstream migration of sediment and associated contaminants through landscapes. Traditional methods for routing contaminated sediment through valleys focus on in‐channel sediment transport but ignore the influence of sediment exchanges with temporary sediment storage reservoirs outside the channel, such as floodplains. In theory, probabilistic analysis of particle trajectories through valleys offers a useful strategy for quantifying the influence of sediment storage on the downstream movement of contaminated sediment. This paper describes a field application and test of this theory, using 137Cs as a sediment tracer over 45 years (1952–1997), downstream of a historical effluent outfall at the Los Alamos National Laboratory (LANL), New Mexico. The theory is parameterized using a sediment budget based on field data and an estimate of the 137Cs release history at the upstream boundary. The uncalibrated model reasonably replicates the approximate magnitude and spatial distribution of channel‐ and floodplain‐stored 137Cs measured in an independent field study. Model runs quantify the role of sediment storage in the long‐term migration of a pulse of contaminated sediment, quantify the downstream impact of upstream mitigation, and mathematically decompose the future 137Cs flux near the LANL property boundary to evaluate the relative contributions of various upstream contaminant sources. The fate of many sediment‐bound contaminants is determined by the relative timescales of contaminant degradation and particle residence time in different types of sedimentary environments. The theory provides a viable approach for quantifying the long‐term movement of contaminated sediment through valleys.
How snowpack heterogeneity affects diurnal streamflow timing
Authors: Lundquist Jessica D. , Dettinger Michael D.
Published: May 2005

Diurnal cycles of streamflow in snow‐fed rivers can be used to infer the average time a water parcel spends in transit from the top of the snowpack to a stream gauge in the river channel. This travel time, which is measured as the difference between the hour of peak snowmelt in the afternoon and the hour of maximum discharge each day, ranges from a few hours to almost a full day later. Travel times increase with longer percolation times through deeper snowpacks, and prior studies of small basins have related the timing of a stream's diurnal peak to the amount of snow stored in a basin. However, in many larger basins the time of peak flow is nearly constant during the first half of the melt season, with little or no variation between years. This apparent self‐organization at larger scales can be reproduced by employing heterogeneous observations of snow depths and melt rates in a model that couples porous medium flow through an evolving snowpack with free surface flow in a channel.
Tide gauge observations of the Indian Ocean tsunami, December 26, 2004
Authors: Merrifield M. A. , Firing Y. L. , Aarup T. , Agricole W. , Brundrit G. , Chang‐Seng D. , Farre R. , Kilonsky B. , Knight W. , Kong L. , Magori C. , Manurung P. , McCreery C. , Mitchell W. , Pillay S. , Schindele F. , Shillington F. , Testut L. , Wijeratne E. M. S. , Caldwell P. , Jardin J. , Nakahara S. , Porter F.‐Y. , Turetsky N.
Published: May 2005

The magnitude 9.0 earthquake centered off the west coast of northern Sumatra (3.307°N, 95.947°E) on December 26, 2004 at 00:59 UTC (United States Geological Survey (USGS) (2005), USGS Earthquake Hazards Program‐Latest Earthquakes, Earthquake Hazards Program, http://earthquake.usgs.gov/eqinthenews/2004/usslav/, 2005) generated a series of tsunami waves that devastated coastal areas throughout the Indian Ocean. Tide gauges operated on behalf of national and international organizations recorded the wave form at a number of island and continental locations. This report summarizes the tide gauge observations of the tsunami in the Indian Ocean (available as of January 2005) and provides a recommendation for the use of the basin‐wide tide gauge network for future warnings.
Increased Intensity of Anticoagulation May Reduce Risk of Thrombus During Atrial Fibrillation Ablation Procedures in Patients with Spontaneous Echo Contrast
Authors: REN JIAN‐FANG , MARCHLINSKI FRANCIS E. , CALLANS DAVID J. , GERSTENFELD EDWARD P. , DIXIT SANJAY , LIN DAVID , NAYAK HEMAL M. , HSIA HENRY H.
Published: May 2005

Introducton:A 10% incidence of left atrial (LA) thrombus formation has been detected using intracardiac echocardiography (ICE) imaging monitoring during LA ablation for atrial fibrillation (AF). The aim of this study was to determine if the intensity of anticoagulation reduces LA thrombus formation during pulmonary vein isolation procedure in patients with AF and spontaneous echo contrast (SEC).

Methods and Results:We studied 511 patients (age 56 ± 10 years) undergoing pulmonary vein ostial isolation/ablation using radiofrequency energy. SEC was detected in 179 of 511 patients with ICE imaging before dual transseptal catheterization. All patients were anticoagulated with heparin to achieve activated clotting time (ACT) 250–300 seconds (group I) or >300 seconds (group II) confirmed at 30‐minute intervals. SEC was detected in 49/294 (16.7%) patients in group I versus 130/217 (59.9%) in group II (P < 0.0001). LA thrombus was observed in 33/294 (11.2%) patients in group I versus 6/217 (2.8%) in group II (P < 0.05). For those patients with SEC, LA thrombus was observed in 22/49 (44.9%) in group I versus 2/61 (4.6%) in group II (P < 0.0001). There were no significant differences in age, number of unsuccessful drugs, persistent AF, left ventricular ejection fraction, and LA diameter between the two groups. No clinical embolic event was observed with withdrawal of LA thrombus to the RA.

Conclusion:ICE‐diagnosed SEC before transseptal catheterization identifies an increased risk of LA thrombus. Increased intensity of heparin anticoagulation (ACT >300 seconds) during LA ablation for AF may prevent LA thrombus formation especially in patients with SEC.
Influence of diffusion of Fe atoms into the emissive layer of an organic light-emitting device on the luminescence properties
Authors: Shikoh Eiji , Ando Yasuo , Miyazaki Terunobu
Published: May 2005

This study investigated magnetic properties of multifilms, Fe∕Al–O (Al-oxide), Fe∕Alq3 (tris-(8-hydroxyquinolinato)-aluminum), and Fe∕Al–O∕Alq3, using vibrating sample magnetometer and ferromagnetic resonance. In the case of Fe∕Alq3-films, the decrease of magnetization value of Fe was observed compared with the other two. It was explained with diffusion of Fe atoms from the underlayer into the Alq3 layer, and those diffused Fe atoms worked as quenching centers in the luminescence process of Alq3.
Cell size corrections for nonzero-temperature micromagnetics
Authors: Kirschner M. , Schrefl T. , Dorfbauer F. , Hrkac G. , Suess D. , Fidler J.
Published: May 2005

Micromagnetic calculations at nonzero temperatures depend on the computational cell size. This paper shows that the spontaneous magnetization MS of exchange-coupled moments has to be scaled by a Bloch-like law, which is similar to the well-known temperature dependence of MS. Using this scaling law, nonatomistic Metropolis Monte Carlo and stochastic Landau–Lifshitz–Gilbert simulations are performed in an external field of 0.1T. The error of the equilibrium magnetization at a temperature of T∕TC=0.38 and a cell size of 1.5nm is then 0.9% as compared with atomistic calculations. In contrast, a cell size-independent MS leads to an overestimation of the temperature of 3.2%.
Spin-polarized current-driven switching in permalloy nanostructures
Authors: Martinez E. , Torres L. , Lopez-Diaz L. , Carpentieri M. , Finocchio G.
Published: May 2005

Spin-polarized current-driven switching processes in a rectangular-shaped permalloy spin valve at deep submicron dimension have been studied by means of micromagnetic modeling. The effect of the magnetostatic antiferromagnetic coupling between ferromagnetic layers has been analyzed. The antiferromagnetic coupling promotes the switching both from parallel to antiparallel transition and backward. Systematic simulations were carried out in order to determine the minimum pulse features needed to switch the magnetization of the free layer. Reversal from antiparallel to parallel state requires shorter and less intense pulses than the reciprocal transition due to the asymmetric character of the spin-polarized current torque.
Wang–Landau estimation of magnetic properties for the Heisenberg model
Authors: Brown G. , Schulthess T. C.
Published: May 2005

The Wang–Landau method is a Monte Carlo procedure for estimating the equilibrium density of states g(E) of spin models, which can then be used to rapidly calculate properties such as the free energy and specific heat as functions of temperature. Here, the Wang–Landau method is validated for the Heisenberg model by comparison with the traditional Monte Carlo estimates, and a procedure for estimating the minimum temperature for valid results is presented. In addition, we show that the Wang–Landau method can be extended to calculate zero-field magnetic properties such as the zero-field susceptibility.
Ferromagnetic Cr-doped ZnO for spin electronics via magnetron sputtering
Authors: Roberts Bradley K. , Pakhomov Alexandre B. , Shutthanandan Vaithiyalingam S. , Krishnan Kannan M.
Published: May 2005

Through nonequilibrium rf magnetron cosputtering of ZnO and Cr metal on a-plane Al2O3 we find ferromagnetic ordering with a room-temperature saturation moment of 1.4μB per Cr ion at a doping concentration of ∼9.5 at. % after UHV postanneal. No secondary phases are detected in the films via x-ray diffraction (XRD). Increased Cr doping causes disorder within the films resulting in decreased overall, and per Cr, moment. The Curie temperature exceeds 365 K, the maximum temperature reached in our experiment. All films are dielectric with a resistivity higher than 106Ωcm at room temperature. The lack of carriers indicates that the ferromagnetic mechanism is not carrier mediated.
Magnetic properties of Co-doped ZnO nanoparticles prepared by vaporization-condensation in a solar reactor
Authors: Martínez B. , Sandiumenge F. , Balcells Ll. , Fontcuberta J. , Sibieude F. , Monty C.
Published: May 2005

We report on the magnetic properties of Co-doped (5% and 10% molar) ZnO nanoparticles prepared by the vaporization-condensation method in a solar reactor. X-ray diffraction patterns do not show evidence of Co segregation or any other phase different from wurtzite-type ZnO. High-resolution electron microscopy shows no traces of Co clusters or any other secondary phase. Samples prepared at 70–100Torr inside glass reactors are paramagnetic and the dominant magnetic interactions are antiferromagnetic in nature. Increasing the Co content promotes a reinforcement of the antiferromagnetic interactions. A reduction of the high-temperature effective paramagnetic moment is also observed.
Micromagnetic simulation studies of ferromagnetic part spheres
Authors: Boardman Richard P. , Zimmermann Jürgen , Fangohr Hans , Zhukov Alexander A. , de Groot Peter A. J.
Published: May 2005

Self-assembly techniques can be used to produce periodic arrays of magnetic nanostructures. We have developed a double-template technique using electrochemical deposition. This method produces arrays of dots which are of spherical shape, as opposed to those prepared by standard lithographic techniques, which are usually cylindrical. By varying the amount of material that is deposited electrochemically, spheres of diameter d can be grown up to varying heights h<d. Thus different spherical shapes can be created ranging from shallow dots to almost complete spheres. Using micromagnetic modeling, we calculate numerically the magnetization reversal of the soft part spherical particles. The observed reversal mechanisms range from single domain reversal at small radii to vortex movement in shallow systems at larger radii and vortex core reversal, as observed in spheres at larger heights. We present a phase diagram of the reversal behavior as a function of radius and growth height. Additionally, we compare simulation results of hybrid finite element/boundary element and finite difference calculations for the same systems.
Micromagnetic studies of vortices leaving and entering square nanoboxes
Authors: Dotse Daniel , Arrott Anthony S.
Published: May 2005

The passage of the virtual vortex of the C state into a square cross-section nanobox proceeds by the development of a direction of polarization to break the symmetry. This happens in a dynamic transition for nanoboxes below a certain height, while for higher nanoboxes there exists a stable polarized C state over a narrow range of applied fields that increases as the square of the excess of the height above the critical height.
Micromagnetic eddy currents in conducting cylinders
Authors: Yanik L. , Della Torre E. , Donahue M. J. , Cardelli E.
Published: May 2005

The inclusion of eddy currents into micromagnetic programs is important for the proper analysis of dynamic effects in conducting magnetic media. This paper introduces a numerical implementation for eddy current calculations, in a limited geometry, for a thick domain wall. In the special case of a zero-thickness wall, our results are directly comparable with an analytical model previously presented. Our calculations provide some computational results for testing more complex programs.
Micromagnetic studies of domain structures and switching properties in a magnetoresistive random access memory cell
Authors: Wu Guoguang , Yu Juan , Wei Fulin , Liu Xiaoxi , Wei Dan
Published: May 2005

Domain structures and switching properties in the free layer of a magnetoresistive random access memory (MRAM) cell are studied, based on a micromagnetic simulation model. A primary design of a MRAM cell for 0-1 data storage requires a single domain structure in the free layer. The stability of the single domain structure is analyzed versus the aspect ratio and the thickness of a cell. The data-storage process in these MRAM cells are studied by applying external fields at different angles and different magnitude. The angular dependence of the switching field is simulated and compared with the Stoner–Wohlfarth model.
Spin transport in an InAs based two-dimensional electron gas nanochannel
Authors: Yi Hyunjung , Koo H. C. , Kim W. Y. , Chang Joonyeon , Han S. H. , Lim S. H.
Published: May 2005

A spin device composed of two ferromagnetic electrodes and InAs two-dimensional electron gas was fabricated. Submicron spin channels were defined to enhance spin transport characteristics. Electrical transport measurement was performed to detect spin-polarized electrons. In potentiometric geometry a voltage change, ΔV=0.17mV, sensed by a ferromagnetic electrode was obtained at 5 and 77K. In the nonlocal method ΔV=0.057mV, which resulted from accumulated spin-polarized electrons, was obtained at 77K. The main reason for theses large signals is that the short and narrow spin channels increase the possibility for spin-polarized electrons to arrive at the spin detector.