bluuebunny/crossref_metadata_2025 huggingface dataset:
NMR structural studies of the myristoylated N‐terminus of ADP ribosylation factor 6 (Arf6)
Authors: Gizachew Dawit , Oswald Robert
Published: July 2006

Arf proteins are guanine nucleotide binding proteins that are implicated in endocytotic pathways and vesicle trafficking. The two widely studied isoforms of Arf proteins (Arf1 and Arf6) have different cellular functions and localizations but similar structures. Arf proteins have an N‐terminal helix with a covalently bound myristoyl group. Except structural models, there are no three dimensional structures of the myristoylated N‐terminal peptide or the intact myristoylated Arf proteins. However, understanding the role of both the myristoyl group and the N‐terminal helix based on the details of their molecular structures is of great interest. In the solution structure of myristoylated N‐terminal peptide of Arf6 described here, the myristoyl group folds toward the N‐terminus to interact with the hydrophobic residues in particular, the phenyl ring. Also, the structure of the dodecylphosphocholine (DPC) micelle‐bound of the peptide together with paramagnetic studies showed that the myristoyl group is inserted into the micelle while residues V4–G10 interact with the surface of the micelle. The structural differences between the unbound and micelle‐bound myristoylated N‐terminal peptide of Arf6 involves the myristoyl group and the side chains of the hydrophobic residues.
Fractalkine and minocycline alter neuronal activity in the spinal cord dorsal horn
Authors: Owolabi Samuel A. , Saab Carl Y.
Published: July 2006

Fractalkine (FKN) evokes nociceptive behavior in naïve rats, whereas minocycline attenuates pain acutely after neuronal injury. We show that, in naïve rats, FKN causes hyperresponsiveness of lumbar wide dynamic range neurons to brush, pressure and pinch applied to the hindpaw. One day after spinal nerve ligation (SNL), minocycline attenuates after‐discharge and responses to brush and pressure. In contrast, minocycline does not alter evoked neuronal responses 10 days after SNL or sciatic constriction, but increases spontaneous discharge. We speculate that microglia rapidly alter sensory neuronal activity in naïve and neuropathic rats acutely, but not chronically, after injury.
Characterization of the last step of lignin biosynthesis in Zinnia elegans suspension cell cultures
Authors: Gabaldón Carlos , López-Serrano Matías , Pomar Federico , Merino Fuencisla , Cuello Juan , Pedreño M.A. , Barceló A. Ros
Published: July 2006

The last step of lignin biosynthesis in Zinnia elegans suspension cell cultures (SCCs) catalyzed by peroxidase (ZePrx) has been characterized. The k
3 values shown by ZePrx for the three monolignols revealed that sinapyl alcohol was the best substrate, and were proportional to their oxido/reduction potentials, signifying that these reactions are driven exclusively by redox thermodynamic forces. Feeding experiments demonstrate that cell wall lignification in SCCs is controlled by the rate of supply of H2O2. The results also showed that sites for monolignol β‐O‐4 cross‐coupling in cell walls may be saturated, suggesting that the growth of the lineal lignin macromolecule is not infinite.
Calmodulin isoform‐specific activation of a rice calmodulin‐binding kinase conferred by only three amino‐acids of OsCaM61
Authors: Li Dian-Fan , Li Jing , Ma Li , Zhang Lei , Lu Ying-Tang
Published: July 2006

The kinase activity of a Ca2+/calmodulin (CaM)‐binding serine/threonine protein kinase from rice (Oryza sativa) (OsCBK) has been reported to be unaffected by OsCaM1 binding. In this study, we examined whether other rice CaMs can stimulate OsCBK. It was observed that OsCaM61 stimulated OsCBK in a Ca2+‐dependent manner. In addition, Ala111, Gly123 and Ser127 were identified as critical residues for OsCBK activation. Mutational study and fluorescent spectroscopy analysis indicated that CaM‐binding affinity does not correlate with the kinase activity and that these key amino‐acids in OsCaM61 play a vital role in suitable changes of OsCBK conformation for kinase activation.
Human lactoferrin upregulates expression of KDR/Flk‐1 and stimulates VEGF‐A‐mediated endothelial cell proliferation and migration
Authors: Kim Chan Woo , Son Kyung-No , Choi Sang-Yun , Kim Jiyoung
Published: July 2006

Lactoferrin (LF) is a multifunctional iron‐binding glycoprotein, which plays a variety of biological processes including immunity. In this study, we demonstrate that human LF upregulates KDR/Flk‐1 mRNA and protein levels in HUVECs at an optimal concentration of 5 μg/ml, which subsequently promotes the VEGF‐induced proliferation and migration of the endothelial cells. Exposure of HUVECs to LF significantly increased VEGF‐induced ERK MAP kinase phosphorylation. The maximal stimulation of KDR/Flk‐1 expression by LF was correlated with LF‐induced increase in cell proliferation and migration. These findings suggest that LF may stimulate in vivo angiogenesis via upregulation of KDR/Flk‐1 expression in endothelial cells.
The escape of juvenile farmed Atlantic salmon from hatcheries into freshwater streams in New Brunswick, Canada
Authors: Carr Jonathan W. , Whoriskey Frederick G.
Published: July 2006

The escape of juvenile Atlantic salmon from freshwater hatcheries supplying the salmon farming industry may lead to interactions between wild and farmed fish. The scale of this problem, however, has not been examined in detail. We monitored temporal trends in the abundance of escaped juvenile farmed salmon in the Magaguadavic River and Chamcook Stream for several years. In addition, in 2004 we assessed more than 90% of the commercial hatcheries producing salmon smolts located next to freshwater streams in New Brunswick. Escaped juvenile fish were recorded in 75% of the streams electrofished close to hatcheries. Numbers varied by site and year. However, escaped juvenile salmon were found every year at sites near hatcheries in the Magaguadavic River and Chamcook Stream. In the Magaguadavic River, juvenile escapees outnumbered wild salmon parr in most years. These results highlight the need for implementation of a containment strategy for freshwater hatcheries to reduce escapes.
Microanatomy in 21 day rat brains exposed prenatally to cocaine
Authors: Buxhoeveden Daniel P. , Hasselrot Ulla , Buxhoeveden Nicole E. , Booze Rosemarie M. , Mactutus Charles F.
Published: July 2006

We examined cell minicolumns, apical dendrite bundles, and inhibitory interneurons, in prefrontal and somatosensory cortex of 21‐day‐old rat brains exposed to cocaine during fetal development. Cell columns and apical dendrite bundles were found to be narrower, or closer together, in all three areas following in utero cocaine exposure. The inter‐rater reliability among different observers was R2 = 0.89. The number of cells stained for glutamic acid decarboxylase (GAD) was not significantly different in the prenatal cocaine exposed group compared to saline controls. The present data suggests that recreational doses of cocaine administered intravenously in early pregnancy, have the capacity to modify the maturation of the ontogenetic cell column.
Differential effects of hypoglossal and facial nerve injuries on survival and growth of rats at different developmental stages
Authors: Fukuyama T. , Yokouchi K. , Fukushima N. , Kawagishi K. , Kakegawa A. , Moriizumi T.
Published: July 2006

The hypoglossal (XII) nerve is made up of functionally different nerve branches: the medial branch related to protrusion of the tongue and the lateral branch related to its retraction. The present study was performed to determine the effects of facial (VII) and XII nerve injuries on the survival and growth of rats in which the unilateral or bilateral VII and XII nerve components (main trunk, XII‐trunk; medial branch, XII‐med; lateral branch, XII‐lat) had been resected at different developmental stages. In the suckling period, unilateral as well as bilateral injuries in the XII‐trunk or XII‐med nerve produced disturbed milk intake, lower survival rates and growth retardation in the nerve‐injured rats. In the transition and mastication periods, only bilateral injury in the XII‐trunk or XII‐med nerve produced disturbed food intake followed by lower survival rates and growth retardation in those animals. The unilateral XII‐lat nerve injury did not have significant effects on milk and food intake, whereas the bilateral injury caused disturbance in milk intake especially at the early neonatal stage. The unilateral VII nerve injury at the early neonatal stage caused deteriorating effects on food intake resulting in lower survival rate and severe growth retardation in the nerve‐injured rats. The results indicate that the survival and growth of XII and VII nerve‐resected rats differ considerably depending on the nerves injured and the developmental ages of the animals at the time of nerve insult.
Is vacuum extraction still known, taught and practiced? A worldwide KAP survey
Authors: Fauveau V.
Published: July 2006

Objective: Is vacuum extraction–the method of first choice for assisting vaginal delivery in case of prolonged labor–losing ground in the developing world? And if it is, why? The paper tries to answer these disturbing questions, and examine their consequences.

Methods: A rapid Knowledge–Attitude–Practice (KAP) survey was conducted during 2003–2004 on the question of assisted vaginal delivery (AVD) by the use of the vacuum extractor. Public health specialists and obstetricians from 121 developing countries were consulted about their knowledge of the method in their country, its reputation (i.e. their attitude) and its use (practice).

Results: Overall 48% of the respondent countries have confirmed knowledge, positive attitude, teaching and countrywide use of the method, while 37% said the method is known and used by only a limited number of specialists who do not teach it, and 15% admitted no knowledge and therefore no use.

Conclusion: Given the evidence‐based international recognition of the benefits of vacuum extraction (if practiced correctly and for appropriate indications), it is unjust to deprive women with prolonged labor (and their fetuses) of a simple intervention that can contribute to reducing life threatening complications. This unsophisticated worldwide survey, while not providing in‐depth explanations, calls for rehabilitation of vacuum extraction in countries where it is disappearing and surgical extraction is not yet readily accessible to all women with prolonged labor.
Breastfeeding: A woman's reproductive right
Authors: Labbok M.
Published: July 2006

This paper explores the importance of breastfeeding as a women's issue in the health and political contexts, covering the role of global institutions, health practitioners, and national decision‐makers in furthering the goals of supporting breastfeeding as a woman's right to health. The roles and responsibilities of the Obstetrician/Gynecologist are highlighted.
Uterine activity and ductus venosus flow velocity patterns during the first stage of labor
Authors: Szunyogh N. , Zubor P. , Dokus K. , Galo S. , Visnovsky J. , Danko J.
Published: July 2006

Objective: To analyze the effects of uterine contractions on ductus venosus (DV) pulsatility during the first stage of labor. Methods: Twenty healthy women were examined. Measurements were taken at three stages of cervical dilatation (< 4 cm, 4–7 cm and ≥ 8 cm) during and between contractions. Peak velocity during ventricular systole (S) and atrial contraction (A), pulsatility index for veins (DV PIV), ductus venosus index (DVI) and the S/A ratio were measured. Results: The DV was observed successfully in 16 cases. The mean S velocity did not change significantly (64 cm/s during and 65 cm/s between contractions). The mean A velocity decreased significantly from 35 cm/s measured between contractions to 29 cm/s during contractions (P < 0.0001). The mean DV PIV and DVI were significantly higher during contractions (0.72 and 0.55) than between contractions (0.57 and 0.45) (P < 0.0001). There were no significant differences in means between stages of cervical dilatation. Conclusion: Significant differences during and between uterine contractions can be observed in DV pulsatility during normal labor.
The SauvÉ-Kapandji Operation
Authors: MILLROY P. , COLEMAN S. , IVERS R.
Published: July 2006

For distal radio-ulnar joint disorders, the Sauvé-Kapandji procedure, previously attributed to Lauenstein, of arthrodesis of the joint and distal ulnar pseudarthrosis is a very useful procedure, yet is not often practised. This paper describes the technique and presents the results of 81 procedures in 71 patients. There was excellent patient satisfaction. The procedure is a reliable and effective method of dealing with distal radio-ulnar joint disorders, especially in rheumatoid arthritis and following distal radial fractures. Some changes to previous techniques are emphasized.
The Plantaris Tendon as a Tendo-Osseous Graft
Authors: SCHLICHT S. M. , MORRISON W. A.
Published: July 2006

Comparative studies have shown that bone-bone union develops faster than a junction between grafted tendon and bone, and would thus allow earlier post-operative movement, limiting adhesion formation. In this context the nature of the insertion of the plantaris tendon into the calcaneus is reviewed as a possible source of composite bone-tendon grafts. It is proposed that the composite plantaris tendon with its bony block attachment is inserted through a hole in the distal phalanx of the finger creating an immediate firm distal fixation. From cadaver dissections it was found that in at least 80% of cases the insertion of the plantaris tendon was directly into the calcaneus, independent of the tendo Achilles, and was therefore suitable for use as the proposed tendon graft.
Himalayan medicinal plant diversity in an ecologically complex high altitude anthropogenic landscape, Dolpo, Nepal
Authors: GHIMIRE SURESH KUMAR , MCKEY DOYLE , AUMEERUDDY-THOMAS YILDIZ
Published: July 2006

The conservation of high-altitude medicinal plants is of concern throughout the Himalayan region, because they are important for traditional health care and in large-scale collection for trade. Because little is known regarding their conservation status in relation to the diversity of land-use patterns and habitats, this paper explores patterns of species composition and diversity of medicinal plants in five different pasture types in a traditionally-managed high-altitude landscape in northwest Nepal. Environmental variables, including human activities, strongly affected species composition, diversity and cover-abundance of medicinal plant species. Species richness of rare and commercially threatened medicinal plants (CTMP) showed patterns similar to overall medicinal plant species richness. Sub-alpine meadows, which have intermediate levels of human pressure related to grazing and relatively high levels of resource availability in terms of rainfall and soil nutrients, were richer in medicinal-plant species than alpine meadows. The coexistence of various plant communities under different human management regimes also enhanced landscape-level species diversity by maintaining some species restricted to particular habitat or pasture types. A number of medicinal plant species reported to be resistant to grazing were most abundant in heavily grazed sites. This pattern suggests that medicinal plant species may be positively influenced, to a certain extent, by human activities (mainly grazing). The combination of grazing and high levels of harvesting, however, had a negative impact on diversity and cover-abundance of rare and CTMP species. Maintenance of medicinal plant diversity and cover-abundance is critically dependent on managing grazing and resource harvesting to maintain levels that are both ecologically and economically sustainable. Forage for livestock and medicinal plants for local health care cannot be managed independently; a systems approach is needed, incorporating social management to accommodate the needs of different users. This could be achieved by maintenance of a mosaic landscape, in which different use patterns and pressures, reflecting the values attached to resources by different users and favouring different types of biodiversity, co-exist.
FUNCTIONAL PEARL: A program to solve Sudoku
Authors: BIRD RICHARD
Published: July 2006

There's no maths involved. You solve the puzzle with reasoning and logic. Advice on how to play Sudoku, The Independent Newspaper
Does the transport of dissolved organic nutrients affect export production in the Atlantic Ocean?
Authors: Roussenov Vassil , Williams Richard G. , Mahaffey Claire , Wolff George A.
Published: July 2006

A simplified cycling and transport model for inorganic nutrients and dissolved organic nitrogen (DON) and phosphorus (DOP) is applied to the Atlantic, on the basis of recent measurements along a meridional transect. The DON and DOP are separated into semilabile pools with a lifetime of 6 months and a refractory pool which is conserved in the interior, but photochemically breaks down in the euphotic zone with a lifetime of 6–12 years. The semilabile pool typically only makes up 10% of the surface DON, but up to 95% of DOP. DON and DOP are preferentially produced over upwelling zones in the euphotic zone. Elevated surface concentrations of DON and DOP generally occur over the tropics where the mixed layer is thin, but become diluted at higher latitudes where the mixed layer is thick. There is a northward transport of DON and DOP from the tropics into the northern subtropical gyre, as part of the Ekman wind‐driven circulation and overturning circulation. At the same time, there is a depth‐integrated southward transport of nitrate and phosphate leading to a loss of nitrate and phosphate over the subtropics of the North Atlantic, which is partly compensated by the supply of DON and DOP. Inputs of DON enhance the particle export over the subtropical gyres by typically 0.05 mol N m−2 yr−1, compared with a background model particle export of typically 0.2 mol N m−2 yr−1. Inputs of DOP appear to be more significant (owing to their smaller refractory content) in increasing particle export by typically 12 mmol P m−2 yr−1 over the subtropical gyre, which is sufficiently large to supply half of the phosphorus requirements for particle export.
Hydromechanics of a high taper angle, low‐permeability prism: A case study from Peru
Authors: Matmon Dorit , Bekins Barbara A.
Published: July 2006

The Peru frontal prism represents a contrasting hydrologic setting to the better characterized systems of Nankai and Barbados. The high taper angle and convergence rate result in rapid burial of low‐permeability sediments. Critical taper stability calculations were combined with a flow model to understand how a steep taper angle could be stable under these conditions. Constant rate flow tests of the slope and prism sediments gave permeability values ranging from a low of ∼10−18 m2 to a high of ∼10−16 m2. Estimated compaction fluid sources exceed 5 × 10−13 s−1 near the toe and remain above 10−14 s−1 for 20 km arcward in the underthrust sediments. These data were used to constrain a two‐dimensional, steady state model of pore pressure along a cross section at 9°S. The model domain is composed of a 15‐km‐wide frontal prism with a crystalline buttress at the back and 500 m of permeable basement at the base. The combined mechanical stability and flow model analysis yielded a feasible basement permeability of ∼10−16 m2 and a décollement permeability range of 10−15–10−17 m2. The model results demonstrate that basement flow and use of different pressure ratio values for the wedge and the base in stability calculations are important for systems with steep taper angles.
Experimental simulation of phase mingling in a subaqueous lava fountain
Authors: Friedman Peter D. , Meyer William J. , Carey Steven
Published: July 2006

Experimental simulations were carried out to determine hydrodynamic flow structures and phase mingling mechanisms of a completely submerged shallow water volcanic vent with the objective of understanding how flow conditions ultimately affect the character and explosiveness of hydromagmatic eruptions. Negatively buoyant jets were produced by injecting glycerin‐water mixtures (magma surrogate) into silicon oil (water surrogate) and imaging the flow structure using a laser/particle image velocimetry system. The experiments were designed to evaluate only the initial mingling processes of magma and water and do not account for subsequent vaporization of water and heat transfer effects. The onset of phase mingling is strongly controlled by the Richardson number of the jet, which governs the flow structure and stability. At Ri <0.90 an oscillatory collapsing fountain is developed, which entrains ambient fluid by vortex rollup and collapsing margins. On the basis of the experimental results the incorporation of water into basaltic magma discharged from a submarine vent of the order of 10 m in diameter is predicted to occur when the volume discharge rate is in excess of 460 m3/s.
Decadal change of the surface water pCO2 in the North Pacific: A synthesis of 35 years of observations
Authors: Takahashi Taro , Sutherland Stewart C. , Feely Richard A. , Wanninkhof Rik
Published: July 2006

Surface water pCO2 data observed over the 3 decades between 1970 and 2004 are analyzed for space and time (mean decadal) variability in thirty‐two 10° × 10° box areas over the North Pacific Ocean north of 10°N. During this period, the pCO2 values at SST increased at a mean decadal rate of 12.0 ± 4.8 μatm decade−1 in all but four areas located in the vicinity of the Bering and Okhotsk Seas, where they decreased at a mean rate of −11.1 ± 5.7 μatm decade−1. The mean rate of increase for the open ocean areas is indistinguishable from the mean atmospheric CO2 increase rate of 15 μatm decade−1 (or 1.5 ppm yr−1) suggesting that the North Pacific surface waters as a whole have been following the atmospheric CO2 increase. However, the rate of increase varies geographically, reflecting differences in local oceanographic processes including lateral mixing of waters from marginal seas, upwelling of subsurface waters and biological activities. The decrease observed in the southern Bering Sea and the peripheries of the Okhotsk Sea may be accounted for by the combined effects of intensified biological production and changes in lateral and vertical mixing in these areas. The natural logarithm of wintertime pCO2 values normalized to a constant temperature and salinity of 14.3°C and 34.0 (the basin mean values, respectively) is correlated with winter SST. Using this relationship, the wintertime TCO2 in mixed layer can be expressed as a function of winter SST with a standard error of ±5 μmol kg−1.
Influence of assimilating rainfall derived from WSR‐88D radar on the rainstorm forecasts over the southwestern United States
Authors: Xu Jianjun , Xiao Qingnong , Gao X. , Sorooshian S.
Published: July 2006

In this study, the impact of rainfall assimilation on the forecasts of convective rainfall over the mountainous areas in the southwestern United States is investigated. The rainfall is derived from the U.S. Weather Surveillance Radar–1988 Doppler (WSR‐88D) radar network, and the fifth‐generation Mesoscale Model (MM5) Four‐Dimensional Variational (4DVAR) system is employed in the study. We evaluate the rainfall assimilation skill through two rainstorm events (5–6 August and 11–12 September 2002) that occurred over the southwestern United States in 2002. A series of experiments for the two cases is conducted. The results show that the minimization process in the 4DVAR is sensitive to the length of assimilation window and error variance in the observation data. Assimilation of rainfall can produce a better short‐range precipitation forecast. However, the time range of improved forecasts is limited to about 15 hours with the model resolution of 20 km. It is indicated that rainfall assimilation produces more realistic moisture divergence and temperature fields in the initial conditions for the two cases. Therefore the forecast of rainstorms is closer to observations in both quantity and pattern.
Use of a regional, relict landscape to measure vertical deformation of the eastern Tibetan Plateau
Authors: Clark M. K. , Royden L. H. , Whipple K. X. , Burchfiel B. C. , Zhang X. , Tang W.
Published: July 2006

Field work and topography analysis show that remnant, local areas of a low‐relief landscape or erosion surfaces are geographically continuous across the southeastern Tibetan Plateau margin. We correlate these remnant surfaces as a paleolandscape that formed at low elevation. Remnants of this paleolandscape are preserved because incision of the fluvial system has been largely limited to major rivers and principal tributaries and has not yet progressed throughout the entire fluvial network. The incomplete adjustment of the fluvial system signals initiation of rapid bedrock incision into a developing plateau margin, and erosional denudation is concentrated in the major river channels. This interpretation contradicts earlier notions that low‐gradient, regional topography is the product of regional elevation reduction by intense landscape dissection due to the presence of several large southeast flowing rivers. The modern altitude of the reconstructed paleolandscape (or “relict landscape”) constrains the vertical displacement of the plateau surface in response to crustal thickening and subsequent erosion during the lateral growth of the Tibetan Plateau. Regional preservation of the relict landscape is consistent with minor surface disruption by late Cenozoic thrust faults and folds and supports a model of distributed lower crustal thickening. Because significant erosion is limited to narrow river gorges, an increase in the plateau elevation due to isostatic rebound is minor. Therefore we propose that the modern elevation of the relict landscape reflects isostatically compensated thickening of the lower crust.
Feedback between deformation and magmatism in the Lloyds River Fault Zone: An example of episodic fault reactivation in an accretionary setting, Newfoundland Appalachians
Authors: Lissenberg C. Johan , van Staal Cees R.
Published: July 2006

The Lloyds River Fault Zone is a 10–15 km wide amphibolite‐grade shear zone that formed during the Ordovician Taconic Orogeny. It separates ophiolites and arc–back‐arc complexes formed in Iapetus from a peri‐Laurentian microcontinent (Dashwoods microcontinent). The Lloyds River Fault Zone comprises three high‐strain zones, dominantly composed of mylonitic amphibolites, separated by less deformed plutonic rocks. Structural, age and metamorphic data suggest the Lloyds River Fault Zone accommodated sinistral‐oblique underthrusting of ophiolites underneath the Dashwoods microcontinent prior to 471 ± 5 Ma at 800°C and 6 kbar. Plutonic rocks within the Lloyds River Fault Zone comprise two suites dated at 464 ± 2 plus 462 ± 2 and 459 ± 3 Ma, respectively. The younger age of the plutons with respect to some of the amphibolites, evidence for magmatic deformation, and the elongate nature of the plutons parallel to the Lloyds River Fault Zone suggest they were emplaced within the fault zone during deformation. Both intrusive episodes triggered renewed deformation at high temperatures (770–750°C), illustrating the positive feedback between deformation and magmatism. Offshoots of the plutons intruded undeformed ophiolitic gabbros outside the Lloyds River Fault Zone. Deformation localized within the intrusive sheets, coeval with static contact metamorphism of the host gabbros, leading to the development of new, small‐scale shear zones. This illustrates that channeling of plutons into shear zones and nucleation of shear zones in melt‐rich zones may occur simultaneously within the same fault system.
Performance of different types of time domain reflectometry probes for water content measurement in partially saturated rocks
Authors: Sakaki Toshihiro , Rajaram Harihar
Published: July 2006

In applying TDR for water content estimation in rocks, the special considerations required include (1) elimination of inaccuracies resulting from gap effects, (2) difficulties in installation of TDR probes, and (3) the need for individual calibration functions between the apparent dielectric constant (Ka) and water content (θ) specific to each rock type. Using seven different rock types, we demonstrate that carefully applied conductive silicone fillings can eliminate gap effects in the case of the penetration‐type probes. We also propose two designs for surface probes, which can be installed relatively easily and are found to be free of errors attributable to gap effects. Measurement accuracy of three probe types is comparable to conventional water content measurement in soils. Error due to the difference in Ka‐θ calibration functions obtained with different probe types is more significant than error due to variation in a single measurement or spatial variability in rock properties.
Decadal to secular time scales variability in temperature measurements over France
Authors: Abarca‐Del‐Rio Rodrigo , Mestre Olivier
Published: July 2006

The influence of inter‐decadal and secular variability on the annual mean air surface temperature variability over France is characterized for the period 1880–2005, together with a description of their regional distribution. After a descriptive study of temperature linear trends over the century, the oscillatory components of the series are investigated through continuous and discrete wavelet transform. This study reveals the importance of inter‐decadal time scales (40–60 and 60–80 years) and particularly the evolution of their phase shift in the latest epoch of the high temperatures rise over France (since 1980).
Ozone pollution from future ship traffic in the Arctic northern passages
Authors: Granier Claire , Niemeier Ulrike , Jungclaus Johann H. , Emmons Louisa , Hess Peter , Lamarque Jean‐François , Walters Stacy , Brasseur Guy P.
Published: July 2006

With sea ice expected to recede in the Arctic during the 21st century as a result of projected climate warming, global shipping patterns will change considerably in the decades ahead. The opening of viable shipping routes through the Northern passages will generate new environmental problems including the degradation of air quality in the Arctic. The release of considerable amounts of carbon monoxide, nitric oxide and other chemical substances by the ship's combustion engines will enhance the level of atmospheric photooxidants and other secondary pollutants in this region. Here we show that, during the summer months, surface ozone concentrations in the Arctic could be enhanced by a factor of 2–3 in the decades ahead as a consequence of ship operations through the northern passages. Projected ozone concentrations of 40–60 ppbv from July to September are comparable to summertime values currently observed in many industrialized regions in the Northern Hemisphere.
Oceanic‐atmospheric variability and western U.S. snowfall
Authors: Hunter Thad , Tootle Glenn , Piechota Thomas
Published: July 2006

A study of the influences of interdecadal and interannual oceanic‐atmospheric influences on April 1 Snow‐Water Equivalent (SWE) in the western U.S. is presented. SWE data was identified at 323 Natural Resources Conservation Service (NRCS) SNOTEL (SNOwpack TELemetrysites) stations for the period of 1961 to 2004 and for 121 SNOTEL stations for the period 1941 to 2004. The phases (cold/negative or warm/positive) of Pacific Ocean [El Niño ‐Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO)] and Atlantic Ocean [Atlantic Multidecadal Oscillation (AMO) and North Atlantic Oscillation (NAO)] oceanic‐atmospheric influences were identified for the year prior to the SWE data set. Statistical significance testing of SWE data set, based on the interdecadal and interannual oceanic‐atmospheric phase (warm/positive or cold/negative) was performed by applying the nonparametric rank‐sum test. The results show that in addition to the well established ENSO signal in the northwest, the PDO and AMO influence SWE variability. Additionally, the coupled effects of the oceanic‐atmospheric influences were evaluated on the basis of the long‐term phase (cold/negative or warm/positive) of the interdecadal (PDO, AMO, NAO) influences and the interannual ENSO. Finally, the coupled effects of the oceanic‐atmospheric influences were evaluated on the basis of the long‐term phase (cold/negative or warm/positive) of the interdecadal (AMO, PDO, NAO) phenomena. Regions in the west were identified that responded to the interdecadal/decadal climatic coupling. By utilizing the April 1 SWE and the long lead‐time approach for the oceanic‐atmospheric variables, useful information can be provided to snow forecasters and water managers.
Evidence that cytochrome b559 is involved in superoxide production in photosystem II: effect of synthetic short-chain plastoquinones in a cytochrome b559 tobacco mutant
Authors: Pospíšil Pavel , Šnyrychová Iva , Kruk Jerzy , Strzałka Kazimierz , Nauš Jan
Published: July 2006

Light-induced production of superoxide (O2•−) in spinach PSII (photosystem II) membrane particles was studied using EPR spin-trapping spectroscopy. The presence of exogenous PQs (plastoquinones) with a different side-chain length (PQ-n, n isoprenoid units in the side-chain) enhanced O2•− production in the following order: PQ-1>PQ-2≫PQ-9. In PSII membrane particles isolated from the tobacco cyt (cytochrome) b559 mutant which carries a single-point mutation in the β-subunit and also has a decreased amount of the α-subunit, the effect of PQ-1 was less than in the wild-type. The increase in LP (low-potential) cyt b559 content, induced by the incubation of spinach PSII membrane particles at low pH, resulted in a significant increase in O2•− formation in the presence of PQ-1, whereas it had little effect on O2•− production in the absence of PQ-1. The enhancement of O2•− formation induced by PQ-1 was not abolished by DCMU [3-(3,4-dichlorophenyl)-1,1-dimethylurea]. Under anaerobic conditions, dark oxidation of LP cyt b559 increased, as pH was decreased. The presence of molecular oxygen significantly enhanced dark oxidation of LP cyt b559. Based on these findings it is suggested that short-chain PQs stimulate O2•− production via a mechanism that involves electron transfer from Pheo− (pheophytin) to LP cyt b559 and subsequent auto-oxidation of LP cyt b559.
Nonlinear growth (and breakdown) of disturbances in developing Hagen Poiseuille flow
Authors: Duck Peter W.
Published: July 2006

The effect of imposing disturbances on developing Hagen Poiseuille flow is investigated for large Reynolds numbers. A formal large Reynolds number analysis is used throughout, which leads to a parabolic approximation (to the Navier-Stokes equations). In this inlet region [which is long O(Reynoldsnumber)×pipe radius], assuming uniform/near uniform inlet flow conditions, the boundary layers develop on the walls of the pipe, that eventually merge. Boundary layers are known to be susceptible to three-dimensional eigensolutions that grow algebraically in the streamwise direction. In this study, nonaxisymmetric disturbances are triggered through (i) the imposition of the aforementioned eigenstates at the pipe inlet and (ii) forcing the azimuthal velocity on the pipe wall. Fully nonlinear, steady disturbances are considered in detail; if the disturbance amplitude is sufficiently large, a solution “breakdown” is observed (associated with a rapid growth of the radial and azimuthal velocity components close to lines of symmetry). This appears to be linked to reversals in both the azimuthal and radial velocity components, suggesting a possible mechanism for flow transition. Some comparison is also made with the analogous effect on planar (Blasius-type) boundary layers. The analysis is wholly rational, with (in particular) the highly nonlinear and nonparallel flow effects being treated in an entirely consistent manner.
Combinatorial study of exciplex formation at the interface between two wide band gap organic semiconductors
Authors: Li G. , Kim C. H. , Zhou Z. , Shinar J. , Okumoto K. , Shirota Y.
Published: July 2006

Combinatorial screening of exciplex formation in blends of 4,4′,4″-tris[2-naphthyl (phenyl)-amino] triphenylamine (2-TNATA), and 2,2′,7,7′-tetrakis(2,2′-diphenylvinyl) spiro-9,9′-bifluorene (spiro-DPVBi) is described. The blended layer was incorporated in ITO/[2-TNATA]/[1:1 2-TNATA:spiro-DPVBi]/[N,N′ - diphenyl - N,N′ - bis (1-naphthylphenyl) - 1,1′ - bi-phenyl - 4,4′-diamine (NPB)]/[spiro-DPVBi]/[tris(8-hydroxy quinoline) Al]/CsF∕Al organic light-emitting devices; the thickness of the blend and NPB layers were varied systematically. The electroluminescence quantum yield decreased as the blended layer thickness increased. The NPB spacer layer reduced the exciplex formation; an 8-nm-thick layer completely suppressed it.
Acceleration and dissipation statistics of numerically simulated isotropic turbulence
Authors: Yeung P. K. , Pope S. B. , Lamorgese A. G. , Donzis D. A.
Published: July 2006

Direct numerical simulation (DNS) data at grid resolution up to 20483 in isotropic turbulence are used to investigate the statistics of acceleration in a Eulerian frame. A major emphasis is on the use of conditional averaging to relate the intermittency of acceleration to fluctuations of dissipation, enstrophy, and pseudodissipation representing local relative motion in the flow. Pseudodissipation (the second invariant of the velocity gradient tensor) has the same intermittency exponent as dissipation and is closest to log-normal. Conditional acceleration variances increase with each conditioning variable, consistent with the scenario of rapid changes in velocity for fluid particles moving in local regions of large velocity gradient, but in a manner departing from Kolmogorov’s refined similarity theory. Acceleration conditioned on the pseudodissipation is closest to Gaussian, and well represented by a novel “cubic Gaussian” distribution. Overall the simulation data suggest that, with the aid of appropriate parameterizations, Lagrangian stochastic modeling with pseudodissipation as the conditioning variable is likely to produce superior results. Reduced intermittency of conditional acceleration also makes the present results less sensitive to resolution concerns in DNS.
Large eddy simulations of transitional round jets: Influence of the Reynolds number on flow development and energy dissipation
Authors: Bogey Christophe , Bailly Christophe
Published: July 2006

Transitional round jets at Mach number M=0.9, with identical initial conditions except for the diameter, yielding Reynolds numbers over the range 1.7×103⩽ReD⩽4×105, are computed by large eddy simulation (LES) using explicit selective/high-order filtering. The effects of the Reynolds number on the jet flows are first presented. As the Reynolds number decreases, the jets develop more slowly upstream from the end of the potential core, but more rapidly downstream. At lower Reynolds numbers, the decay of the centerline velocity and the jet spreading are indeed faster, and the turbulence intensities are higher after the potential core, in agreement with data of the literature. The integral length scales are also significantly larger. The results suggest moreover that the jet self-similar region is reached at shorter axial distances at lower Reynolds numbers. The influence of the Reynolds number on the energy-dissipation mechanisms involved in the LES, namely molecular viscosity and explicit filtering, is secondly investigated. At high Reynolds number, energy dissipation is mainly ensured by the explicit filtering, through the smaller scales discretized. As the Reynolds number decreases, the contribution of molecular viscosity increases and becomes predominant. Molecular viscosity is also shown to affect a large range of turbulent scales with a dissipation peak observed around the Taylor length scale.
Two-dimensional simulations of flow near a cavity and a flexible solid boundary
Authors: Yin Xiuyan , Kumar Satish
Published: July 2006

Two-dimensional fluid flow near a cavity and a flexible solid boundary is examined in this work. Stokes’ equations are used to describe the fluid flow, while the flexible solid boundary is modeled as a uniformly tensioned membrane. Equations for elliptic mesh generation are solved iteratively along with Stokes’ equations, and the equation describing the membrane is used to update its position during the iterations. Two different configurations are considered. In the first, flow passes through the gap between a moving flexible wall and a rigid cavity. This configuration is studied in order to verify the validity of a lubrication model for this flow which was developed in previous work [X. Yin and S. Kumar, Phys. Fluids 17, 063101 (2005)]. In the second, flow driven by an externally applied pressure gradient passes through the gap between a stationary rigid wall and a cavity with a flexible bottom wall that can be deformed by an external pressure. This configuration is studied in order to explore the effect of boundary deformation on the flow pattern in the cavity. The results for the first configuration indicate that the lubrication model yields good predictions of the pressure profile, position of the flexible wall, and flow rate. The comparison also confirms that the lubrication model can only predict the existence of one primary eddy in the cavity, but not multiple primary eddies or corner eddies. The results for the second configuration indicate that the flow pattern in the cavity is dramatically altered as the external pressure changes. Replacing the bottom of a cavity with a flexible wall and applying a time-periodic pressure to it may thus be a potentially useful way to improve mixing and heat/mass transport in the cavity.
Wake state and energy transitions of an oscillating cylinder at low Reynolds number
Authors: Leontini J. S. , Stewart B. E. , Thompson M. C. , Hourigan K.
Published: July 2006

This paper reports on an extensive parameter space study of two-dimensional simulations of a circular cylinder forced to oscillate transverse to the free-stream. In particular, the extent of the primary synchronization region, and the wake modes and energy transfer between the body and the fluid are analyzed in some detail. The frequency range of the primary synchronization region is observed to be dependent on Reynolds number, as are the wake modes obtained. Energy transfer is primarily dependent on frequency at low amplitudes of oscillation, but primarily dependent on amplitude at high amplitudes of oscillation. However, the oscillation amplitude corresponding to zero energy transfer is found to be relatively insensitive to Reynolds number. It is also found that there is no discernible change to the wake structure when the energy transfer changes from positive to negative.
The swimming of animalcules
Authors: Felderhof B. U.
Published: July 2006

Animalcules can swim in a viscous fluid at low Reynolds number and low Stokes number by moving their body parts in a periodic coherent fashion. The swimming motion is analyzed in a simple model of beads subject to periodic one-body forces. In the model the animalcule is held together by reactive two-body forces. The nonlinear equations of Stokesian dynamics are formulated on the basis of the Oseen tensor. Under suitable conditions the solution of the equations of motion has a limit cycle character. The limit cycle is analyzed for small amplitude motion in the framework of a bilinear theory. The linearized equations of motion are solved analytically for longitudinal and transverse modes of motion for a linear trimer, and expressions are derived for the swimming velocity and the mean dissipation to second order in the force amplitude. The results of the bilinear theory are compared to numerical solution of the nonlinear equations of motion. A similar comparison is made for chains of twelve beads.
Turbulent drag reduction by the seal fur surface
Authors: Itoh Motoyuki , Tamano Shinji , Iguchi Ryo , Yokota Kazuhiko , Akino Norio , Hino Ryutaro , Kubo Shinji
Published: July 2006

The drag-reducing ability of the seal fur surface was tested in a rectangular channel flow using water and a glycerol-water mixture to measure the pressure drop along the channel in order to evaluate friction factors in a wide range of Reynolds number conditions, and the drag reduction effect was confirmed quantitatively. The maximum reduction ratio was evaluated to be 12% for the glycerol-water mixture. The effective range of the Reynolds number, where the drag reduction was remarkable, was wider for the seal fur surface compared to that of a riblet surface measured in this channel and in previous studies. It was also found that for the seal fur surface, unlike riblets, any drag increase due to the effect of surface roughness was not found up to the highest Reynolds number tested. Measurements of the seal fur surface using a 3D laser microscope revealed that there were riblet-like grooves, composed of arranged fibers, of which spacings were comparable to that of effective riblets and were distributed in various wavelengths. Using LDV measurements, it was found that the difference in the mean velocity scaled by the outer variable among the smooth, riblet, and seal fur surfaces did not appear at any spanwise locations. Streamwise turbulence intensity for the seal fur surface was found to be about 5% smaller than those for smooth and riblet surfaces.
Particle concentration in homogeneous shear turbulence simulated via Lagrangian and equilibrium Eulerian approaches
Authors: Shotorban Babak , Balachandar S.
Published: July 2006

Direct numerical simulation is conducted to study particle concentration in particle-laden homogeneous shear turbulence. The equilibrium assumption in which the velocity of particles is approximated in terms of the velocity and acceleration of the fluid phase is assessed for this flow by analyzing the radial distribution function (RDF), the probability density function (PDF) of the number density of particles, the autocorrelation of particle Lagrangian velocity, and the particle turbulent diffusivity for various particle time constants. A good agreement between exact and equilibrium Lagrangian particles is observed for these statistics when nondimensional particle time constant τp*<0.6. In this work, we also introduce a new methodology for measuring the anisotropy of the Lagrangian particle concentration through calculating two-dimensional RDFs. It is shown that particles are the most and least accumulated in the streamwise and cross-stream directions, respectively. Also, a methodology is introduced to extract a spatially smooth number density of particles from discrete Lagrangian particles by employing a locally averaged formulation. In this work, the equilibrium Eulerian equations are reformulated for the case of homogeneous shear turbulence as well and the concentration of particles are simulated in a Eulerian framework by solving the corresponding transport equation. A good agreement between the exact Lagrangian and equilibrium Eulerian results is observed. The governing equations of the fluid phase along with the concentration transport equation of the particle phase are solved by a pseudospectral method.