bluuebunny/crossref_metadata_2025 huggingface dataset:
Forage Legume Regeneration from the Soil Seed Bank in Western North Dakota
Authors: Carr Patrick M. , Poland Woodrow W. , Tisor Lee J.
Published: July 2010

Rotating wheat (Triticum spp.) with fallow cannot be sustained in the Great Plains. Replacing fallow with legume pasture enhanced wheat production in Australian ley farming. The legume species used in ley farming regenerated from seed produced during previous pasture periods. Our objective was to identify legumes that regenerated from the seed bank in western North Dakota. Ten legume species were established in one experiment, 30 species in a second experiment, and 29 species in a third experiment. Seedlings were counted in the spring following the year of establishment. Over 200 seedlings m−2 germinated in balansa clover (Trifolium michelianum Savi), berseem clover (T. alexandrinum L.), birdsfoot trefoil (Lotus corniculatus L.), black medic (Medicago lupulina L.), burr medic (M. polymorpha L.), crimson clover (T. incarnatum L.), Persian clover (T. resupinatum L.), and red clover (T. pratense L.) plots in at least one experiment. Forage dry matter yield ranged from 2 to 5 Mg ha−1 for birdsfoot trefoil and red clover depending on the experiment and was similar to forage yield by alfalfa (M. sativa L.) that persisted in the second year following establishment (P > 0.05). Crude protein, acid detergent fiber, and neutral detergent fiber concentrations suggested that forage quality was equal or superior for birdsfoot trefoil compared with alfalfa and red clover. Birdsfoot trefoil has potential as a self‐seeding pasture species in the Great Plains.
Tillage System, Preceding Crop, and Nitrogen Fertilizer in Wheat Crop: II. Water Utilization
Authors: López‐Bellido Rafael J. , López‐Bellido Luis , Benítez‐Vega Jorge , López‐Bellido Francisco J.
Published: July 2010

Under rainfed Mediterranean conditions, where water constitutes the limiting factor, the aim is to obtain the highest production per unit of available water. A 6‐yr study in a Vertisol was undertaken to determine in wheat (Triticum aestivum L.) the effects of tillage system, preceding crop, and N fertilizer on water utilization. Tillage treatments were no‐tillage and conventional tillage. Preceding crops, in 2‐yr rotations, were sunflower (Helianthus annuus L.), chickpea (Cicer arietinum L.), faba bean (Vicia faba L.), fallow, and continuous wheat. The mean crop precipitation interception index (CPI) was low (43%). Rotations including spring‐planted crops such as chickpea and sunflower, or including fallow, reduced the CPI, increasing the risk of erosion. The tillage system did not affect any of the parameters studied. Water use efficiency (WUE) ranged from 5 to 14 kg ha−1 mm−1. Wheat and sunflower as preceding crops yielded poorer values for productivity and water utilization, while the best results were obtained with faba bean. The highest values of precipitation use efficiency (PUE) and WUE were reached with 100 kg N ha−1 in all rotations except for wheat–sunflower, which needed 150 kg N ha−1. The inclusion of faba bean or chickpea in a 2‐yr rotation contributes to improve the WUE by wheat crop.
Effect of Phosphate Source, Lime, and Time of Phosphate Application on Absorption of Applied Phosphorus by Plants
Authors: Chin N. L. , Ray H. E. , Caldwell A. C. , Hustrulid A.
Published: July 2010

Effects of P source, rate of liming, and time of contact between fertilizer and soil on the availability and uptake by plants of phosphatic fertilizers applied to several Minnesota soils have been studied in greenhouse experiments.

Monocalcium phosphate resulted in significantly higher yields and lower P contents of wheat than dicalcium phosphate, and was more available to both wheat and alfalfa.

Alfalfa yields generally increased with an increase in the rate of liming. Liming had no apparent effect on the total P content of wheat or alfalfa, but the uptake by alfalfa of P from applied monocalcium phosphate was increased by the 4‐ton per acre rate of lime application. With both phosphate sources, alfalfa yields were highest on the alkaline soils, and lowest on an acid soil.

Time of phosphate application had no consistent effect on growth rate or dry matter production of oats, although yield responses to phosphate fertilization were obtained on four soils. Phosphorus content of oats was generally increased when fertilizer was applied ahead of the planting date. Availability of applied phosphate tended to decrease on two high pH soils when fertilizer was applied 20 days or more ahead of planting.
Rate of Potassium Release from Fixed and Native Forms
Authors: Ellis Boyd G. , Mortland M. M.
Published: July 2010

The rate of release of K from fixed and native forms was compared utilizing a biotite‐vermiculite system. Although X‐ray diffraction patterns of oriented aggregates showed little difference between native biotite and weathered biotite containing fixed K, there was a marked difference in the rates of K release from the two materials. The release from native biotite was maintained at nearly a constant rate while approximately 50% of the K was removed, whereas with the fixed forms, rate of release decreased with time. The relationship between the logarithm of the rate of release and time was linear. The slopes of these curves were directly related to the extent of weathering which the weathered biotite had undergone before being subjected to the fixation reaction. The ease of release of fixed K therefore appears to be a function of the extent of weathering of the mica. This may be the result of loss of charge in the mineral during weathering.
Water Retention by Capillary Forces in an Ideal Soil
Authors: Waldron L. J. , McMurdie J. L. , Vomocil J. A.
Published: July 2010

In a system of air, water and solid spheres of uniform size the water content by volume may be expressed as a function of the pressure drop across an air‐water interface. Such an expression has been obtained by R. A. Fisher (1926).

The validity of the Fisher theory was tested by making water extractions from saturated packs of equal size (monodisperse) glass beads. The extractions were made by means of pressure plate, centrifuge, osmotic solution and pressure membrane techniques. The glass spheres were Minnesota Mining and Manufacturing Co. “Superbrite” glass beads of 51, 99, and 203µ diameter.

The data show that at all values of suction the amount of water retained by the pack of glass beads greatly exceeds the amount predicted by the Fisher capillary theory.

This result indicates that a mechanism in addition to the pressure drop across the air‐water interface is involved in the retention of water in coarse‐grained, “noninteracting” materials. The lack of agreement may be a consequence of the omission of an adsorptive mechanism in this application of capillary theory.
A Comparison of Tree Responses to Fertilizers in Field and Pot Experiments
Authors: Mead D. J. , Pritchett W. L.
Published: July 2010

Eight uniform fertilizer experiments with Pinus elliottii Engelm. were established in the field between 1959–1962 on six soils ranging from excessively drained fine sands to poorly drained sandy loams. Soils from these experiments were used in pot tests, following similar treatments. Seedlings were grown for 8 months. No single measure of seedling response to treatments (height, diameter at soil surface, dry weight of tops, total dry weight) consistently correlated with field responses, expressed in terms of average tree height. There were large differences between field and greenhouse experiments in both type and degree of response obtained from the various soils. The best correlation (r = 0.66) was between seedling total dry weight and tree height at age 7. Height of greenhouse seedlings was the poorest method of those tested for predicting field response. All results from pot experiments were more poorly correlated with tree heights in the field after 3 years than after 7 years. The role of greenhouse experiments in studying deficiency symptoms and as a diagnostic tool for determining limiting nutrients is well recognized, but results must be used with caution for predicting magnitude of fertilizer response in the field.
Physical and Chemical Properties of the Forest Floor in Birch and Aspen Stands in Interior Alaska
Authors: Van Cleve Keith , Noonan Laraine L.
Published: July 2010

This study was conducted to establish the mass and nutrient status of the forest floor in quaking aspen (Populus tremuloides Michx.) and paper birch (Betula papyrifera Marsh.) forests in interior Alaska. Results of this investigation show that aspen forests have a greater mass of organic matter and nutrient elements in the forest floor than birch forests. The more favorable base status in aspen forest floors is reflected in higher pH and lower exchangeable hydrogen than encountered in birch forest floors. Increasing degree of organic matter decomposition in the forest floor of both vegetation types (L layer > F layer > H layer) is associated with increased N content and cation exchange capacity of the organic matter in the respective layers.
Assessing Boron Needs for Improving Peanut Yield and Quality
Authors: Hill W. E. , Morrill L. G.
Published: July 2010

Three experiments were conducted to determine requirements of boron (B) for Spanish peanuts (Arachis hypogaea); (i) three rates of B were applied in solution to soil surfaces at 17 field locations, (ii) two rates of B were applied to soil at various stages of growth, and (iii) four B carriers were compared. Soil samples were collected at planting time. Leaf and petiole samples were collected 30 and 60 days after planting. The relationship of the occurrence of internal damage to initial soil B levels and concentration of B in plant tissue were evaluated. The effects of time, rate, and B carrier were also compared.

Boron deficiency was found in more than 50% of the field locations. Boron application did not increase yields of peanuts or improve seed quality as measured by yield of sound mature kernels. The occurrence of internal damage from B deficiency (IDB) was shown to be related to hot‐water‐soluble soil B and to B content in young leaves and petioles. No IDB was found at locations with a hot‐water‐soluble soil B level > 0.15 ppm. Peanuts from plants with B concentration in young leaf tissue between 26 to 30 ppm at 30 and 60 days after planting were free of IDB. Boron applied as late as 60 days after planting was effective in eliminating IDB. No difference in the effectiveness of the four B carriers was found.
Depth Distribution and Seasonal Populations of Mesquite‐Nodulating Rhizobia in Warm Desert Ecosystems
Authors: Jenkins Michael B. , Virginia Ross A. , Jarrell Wesley M.
Published: July 2010

Deeply rooted woody legumes are common in desert ecosystems yet little is known about the distribution of their rhizobial symbionts in relation to their roots and soil properties of the systems. The distribution of mesquite (Prosopis glandulosa Torr.)‐nodulating rhizobia was investigated to depths of 13 m in warm desert ecosystems. Soils were collected under mesquite from sand dune and playa ecosystems in the California Sonoran Desert, and from sand dune, playa, arroyo, and grassland ecosystems in the Chihuahuan Desert of southern New Mexico. A Larrea tridentata (DC.) Coville (creosote bush) ecosystem in New Mexico, containing no mesquite, was sampled as a reference. Three intact soil cores from each ecosystem were removed during the winter, spring, and fall from the New Mexico sites, and the winter from the California sites. Significant rhizobial population densities were measured in soil from 1‐ to 4‐m depths at the sand dune, arroyo, and playa ecosystems. At the playa ecosystem in New Mexico population densities > 105 cells kg−1 were measured in soils from 8‐m depth, and root nodules containing rhizobia were recovered in soil samples from 3‐, 4‐, and 7‐m depths. Multipleregression analysis of rhizobial concentration against soil NH4‐N, PO4‐P, electrical conductivity, and gravimetric water content indicated that no single soil factor was related significantly to rhizobial concentration across the ecosystems. Rhizobial densities varied with season in the dune and arroyo ecosystems. In these desert ecosystems significant rhizobial populations, root nodules, and presumably symbiotic N2 fixation occur at soil depths rarely studied.
Modeling Magnesium Uptake from an Acid Soil. II. Barber‐Cushman Model
Authors: Rengel Z. , Robinson D. L.
Published: July 2010

A better understanding of the processes that are involved in the absorption of Mg may lead to improved management practices to avoid high grass tetany potential of forage. Two ryegrass (Lolium multiflorum Lam.) cultivars were grown in a greenhouse on an acid Stough soil (a coarse‐loamy, siliceous, thermic Fragiaquic Paleudult) amended with three rates each of CaO and MgCl2. Linear, lime‐rate‐dependent relationships between exchangeable and soil‐solution Mg were found. The slopes of these relationships (Mg buffer power) were 0.68, 1.31, and 1.21 for lime rates 0, 1, and 3 g kg−1, respectively. The Barber‐Cushman nutrient‐uptake model consistently overpredicted observed Mg uptake by 1.15 to 1.70 times, depending on the Mg application rate. Model calculations showed accumulation of Mg at the root surface. Sensitivity analyses revealed that large values of maximal net Mg influx (Imax) were the reason for overprediction of Mg uptake. Using input parameters based on soil‐solution Mg activities lowered the overprediction to 1.10 to 1.61 times the observed uptake. A major obstacle to using the Barber‐Cushman model for predicting Mg uptake is the lack of information about kinetic parameters of plant uptake from soil solution.
Air Pressure Fluctuations in a Prairie Soil
Authors: Renault Pierre , Mohrath Dalila , Gaudu Jean‐Claude , Fumanal Jean‐Claude
Published: July 2010

The influence of air convection on soil aeration has not been investigated in great detail. A study was conducted to measure air pressure changes by depth in the first 2 m of a prairie soil that was known for its denitrification properties. An absolute air pressure probe was used to measure air pressure fluctuations at the soil surface and newly designed differential air pressure probes were placed at depths of 0.1, 0.2, 0.3, 0.4, 0.5, 0.75, 1, 1.5, and 2 m. A procedure of in situ recalibration was used every 6 or 7 wk for these probes. At the same depths, capacitive probes and thermocouples measured the volumetric water content and temperature, respectively. The bulk density profile, water table level, and rainfall amounts were recorded. The atmospheric pressure ranged between 97 000 and 101 000 Pa during the experiment. The signal drift of the air pressure probes was negligible for four of the probes and <50 Pa for the others. The accuracy of the measurements with signal drift compensation was superior to 10 Pa. Differences of air pressure between the soil at the surface and at depth may be >2000 Pa. These differences, which are not necessarily linked to the depth, are probably due to soil heterogeneities and generally to water infiltration. Air pressure seemed to level out quickly when the air‐filled pore space was continuous. This generally prevented “dephasing‐amortization” effects. When the air‐filled pore space was discontinuous, differential air pressures depended simultaneously on the atmospheric pressure and temperature fluctuations.
Changes in Soil Water Retention Curves Due to Tillage and Natural Reconsolidation
Authors: Ahuja L. R. , Fiedler F. , Dunn G. H. , Benjamin J. G. , Garrison A.
Published: July 2010

Changes in soil water retention of the surface soil brought about by tillage can significantly alter the amount of rain water that infiltrates into the root zone and is available for plant growth. Soil tillage generally increases porosity and changes the pore‐size distribution, leading to changes in the soil water retention curve and hydraulic conductivities. The objective of this study was to investigate some simple ways of estimating the soil water retention curve of a tilled soil from that of an untilled soil, knowing the change in soil porosity or bulk density due to tillage. The study of literature and empirical analysis of the available data indicated: (i) under field conditions the tillage did not significantly change the air‐entry value of the soil; (ii) tillage increased the absolute value of the slope of the log‐log relationship below the air‐entry value; and (iii) the changes due to tillage in the retention curve occurred only in the larger pore‐size range, approximately between the air‐entry pressure head value and 10 times the air‐entry value. Assuming these observations hold in general, two simple methods of estimating the water retention curve of a tilled soil from that of its untilled condition are proposed. The first method is a simple imposition of the Brooks and Corey function between the air‐entry value and 10 times this value. The second method assumes that the change in soil water content at a given pressure head in the above range of pressure heads was inversely proportional to the value of the pressure head. The tests on four pairs of measured water retention curves on three different soils showed that these methods provided good approximations.
Determination of the period of major runoff decline and related driving factors in Ye River Basin, North China
Authors: Tian Fei , Yang Yonghui , Han Shumin , Moiwo Juana P. , Qiu Guoyu
Published: July 2010

There is a sharp decline in runoff and available water resources in North China in recent years. Not only the causes, but also the magnitudes, especially of the dwindling runoff remain largely unclear. Hence the Ye Rive Basin, a typical mountain watershed in North China, is used in this study to determine: (1) the trend of precipitation and runoff via a Mann–Kendall test; (2) the period of drastic runoff decline via a sequential Mann–Kendall test and (3) the driving factors of runoff decline via (i) runoff comparisons for dry and wet years with similar precipitation events, and (ii) regression comparisons on precipitation and runoff for the pre- and post-development periods. Analysis of 40 years (1960–1999) of data shows a significant decline in annual runoff, whereas annual precipitation remains relatively stable. In the basin, runoff decline started in 1974, and became drastic in 1978. Furthermore, runoff analysis for typical dry and wet years, and regression comparisons, indicate that human activity is the main driving factor of runoff decline in the basin. Agricultural water use is the dominant cause of the drastic hydrological changes in the study area.
Floristic Composition of Weeds in Paddy Fields in Mahendranagar, Nepal
Authors: Bhatt M. D. , Tewari A. , Singh S. P.
Published: July 2010

Field experiments were conducted during 2004 and 2005 in paddy fields to evaluate the floristic composition of weeds, in lowland and upland areas of Mahendranagar, Nepal. A total of 61 weed species belonging to 42 genera and 23 families were recorded. Of the 23 families, Cyperaceae was the largest (13 spp.), followed by Poaceae (11 spp.), Euphorbiaceae (4 spp.), Amaranthaceae, Commelinaceae and Asteraceae (3 spp. each), Polygonaceae (2 spp.) and one species each belonged to Apiaceae, Acanthaceae, Alismataceae, Pontederiaceae, Leguminosae, Convolvulaceae, Eriocaulaceae, Marsileaceae, Malvaceae, Oxalidaceae, Onagraceae, Parkeriaceae, Portulaceae, Rubiaceae and Verbenaceae. The number of weed species was higher in upland (55) when compared with the lowland sites (48). On the basis of Importance Value Index (IVI) dominating weed species in paddy fields were: Fimbristylis miliacea (13.4), Lindernia oppositifolia (13.2), Eleocharis atropurpurea (13.1), Ageratum conyzoides (13.0), Cyperus iria (13.0), Echinochloa crus-galli (11.9), Ischaemum rugosum (11.7), Echinochloa colona (11.4), Cyperus difformis (11.1) and Schoenoplectus juncoides (11.0). Besides dicots and monocots, two species of pteridophytes (Ceratopteris thalictriodes and Marsilea minuta) were also recorded in lowland paddy fields. Key words: Paddy, weeds, upland, lowland, IVI. DOI: 10.3126/eco.v16i0.3468ECOPRINT 16: 15-19, 2009
Robert Brown on Pterocymbium (Sterculiaceae)
Authors: MABBERLEY D J
Published: July 2010

SUMMARY

Robert Brown's use of pamphlets as a medium for disseminating his work is explained and the necessary resultant amendments in nomenclatural citation pointed out. The pamphlets associated with Horsfield's Plantae javanicae rariores are described, the existence of the second of these, Pterocymbium, having come to light in only 1984. It was published in June 1844, some five months before the text appeared in Plantae javanicae rariores under the general supervision of Bennett. New names of genera and species (largely referable to Sterculiaceae, but also Euphorbiaceae) are attributable to Brown alone.
A preliminary note on the publication dates of H. C. Andrews' Coloured engravings of heaths (1794–1830)
Authors: CLEEVELY* R. J. , OLIVER* E. G. H.
Published: July 2010

ABSTRACT:

An account is given of this major work on Cape heaths (Erica spp) produced during a period that such plants were fashionable. The first volume (1794–1802), originally published in parts, contained the author's explanation and a dissertation on the history and cultivation of these species. None of the plates in its four volumes was numbered so that subscribers could make their own arrangements, but both alphabetical and systematic lists were provided. The copyright acts of that period required the date of issue to be stated, and lists of these help to establish the dates of publication of the names of the new species described. Examination of the engraved dates and other evidence indicates that the following dates can be applied to Coloured engravings of heaths: original parts 1794–1802, volume I “1802”, volume II “1805x201D;, volume III “1809x201D; and volume IV 1810–1830, but these are subject to further work. These dates have also been used to infer the probable contents of the earlier parts which the discovery of a set of the original 23 numbers has since confirmed.
Effect of exercise intervention on thigh muscle volume and anatomical cross‐sectional areas—Quantitative assessment using MRI
Authors: Hudelmaier Martin , Wirth Wolfgang , Himmer Maria , Ring‐Dimitriou Susanne , Sänger Alexandra , Eckstein Felix
Published: July 2010

The objective of this study was to evaluate the location‐specific magnitudes of an exercise intervention on thigh muscle volume and anatomical cross‐sectional area, using MRI. Forty one untrained women participated in strength, endurance, or autogenic training for 12 weeks. Axial MR images of the thigh were acquired before and after the intervention, using a T1‐weighted turbo‐spin‐echo sequence (10 mm sections, 0.78 mm in‐plane resolution). The extensor, flexor, adductor, and sartorius muscles were segmented between the femoral neck and the rectus femoris tendon. Muscle volumes were determined, and anatomical cross‐sectional areas were derived from 3D reconstructions at 10% (proximal‐to‐distal) intervals. With strength training, the volume of the extensors (+3.1%), flexors (+3.5%), and adductors (+3.9%) increased significantly (P < 0.05) between baseline and follow‐up, and with endurance training, the volume of the extensor (+3.7%) and sartorius (+5.1%) increased significantly (P < 0.05). No relevant or statistically significant change was observed with autogenic training. The greatest standardized response means were observed for the anatomical cross‐sectional area in the proximal aspect (10–30%) of the thigh and generally exceeded those for muscle volumes. The study shows that MRI can be used to monitor location‐specific effects of exercise intervention on muscle cross‐sectional areas, with the proximal aspect of the thigh muscles being most responsive. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Compositional and Antioxidant Activity Analysis of Zanthoxylum bungeanum Seed Oil Obtained by Supercritical CO2 Fluid Extraction
Authors: Xia Lian , You Jinmao , Li Guoliang , Sun Zhiwei , Suo Yourui
Published: July 2010

Supercritical CO2 fluid extraction (SFE‐CO2) of Zanthoxylum bungeanum (Z. bungeanum) seed oil was investigated. To optimize the SFE process, three‐level Box‐Behnken factorial design and response surface methodology (RSM) were applied to optimize the extraction conditions, including pressure, temperature and amount of modifier. The optimum conditions were as follows: extraction pressure, 29.28 MPa; extraction temperature, 41.19 °C; and the added amount of modifier, 10.94%. The experimental results showed that the maximum extraction yield was 21.85 ± 0.23% (n = 3) under the proposed conditions. The compositional analysis of Z. bungeanum seed oil was performed by HPLC‐FLD‐MS using a new labeling reagent of 2‐(11H‐benzo[a]carbazol‐11‐yl)‐ethyl‐4‐methyl benzenesulfonate (BCETS). The results indicated that the Z. bungeanum seed oil contained mainly unsaturated fatty acids, including C18:3, C22:6, C20:4, C18:2, C18:1 and C20:1, which accounted for 84.0% (mass percentage) of the total amount. The antioxidant activity of seed oil obtained by Box‐Behnken design concerning the DPPH radical was investigated, and this indicated that the pressure and the amount of added modifier had positive effects on the antioxidant activity, but the effect of the temperature elevation is complicated, depending on the nature of the extracted contents.
Can social support protect bullied adolescents from adverse outcomes? A prospective study on the effects of bullying on the educational achievement and mental health of adolescents at secondary schools in East London
Authors: Rothon Catherine , Head Jenny , Klineberg Emily , Stansfeld Stephen
Published: July 2010

This paper investigates the extent to which social support can have a buffering effect against the potentially adverse consequences of bullying on school achievement and mental health. It uses a representative multiethnic sample of adolescents attending East London secondary schools in three boroughs. Bullied adolescents were less likely to achieve the appropriate academic achievement benchmark for their age group and bullied boys (but not girls) were more likely to exhibit depressive symptoms compared to those not bullied. High levels of social support from family were important in promoting good mental health. There was evidence that high levels of support from friends and moderate (but not high) family support was able to protect bullied adolescents from poor academic achievement. Support from friends and family was not sufficient to protect adolescents against mental health difficulties that they might face as a result of being bullied. More active intervention from schools is recommended.
Differentiating three conceptualisations of the relationship between positive development and psychopathology during the transition to adulthood
Authors: O’Connor Meredith , Sanson Ann , Hawkins Mary T. , Toumbourou John W. , Letcher Primrose , Frydenberg Erica
Published: July 2010

The transition to adulthood is characterised by both great potential for positive change and a relatively high incidence of problem outcomes. A multidimensional model of positive development during the transition to adulthood (at 19–20 years) has recently been proposed. However, an unresolved question regarding the nature of positive development during this time is how best to conceptualise its relationship to psychopathology. We drew on data from 1158 participants in the Australian Temperament Project, a large longitudinal community‐based study that has followed young people’s psychosocial adjustment from infancy to early adulthood. Using structural equation modelling, we compared three models reflecting different conceptualisations of the relationship between positive development and psychopathology. The results suggest that positive development and psychopathology are best modelled as separate but correlated constructs. Hence, development in one domain is likely to influence the other, although separate and specific developmental pathways are also likely to be operating.
Mental motor imagery indexes pain: The hand laterality task
Authors: Coslett H. Branch , Medina Jared , Kliot Dasha , Burkey Adam R.
Published: July 2010

Mental motor imagery is subserved by the same cognitive systems that underlie action. In turn, action is informed by the anticipated sensory consequences of movement, including pain. In light of these considerations, one would predict that motor imagery would provide a useful measure pain‐related functional interference. We report a study in which 19 patients with chronic musculoskeletal or radiculopathic arm or shoulder pain, 24 subjects with chronic pain not involving the arm/shoulder and 41 normal controls were asked to indicate if a line drawing was a right or left hand. Previous work demonstrated that this task is performed by mental rotation of the subject's hand to match the stimulus. Relative to normal and pain control subjects, arm/shoulder pain subjects were significantly slower for stimuli that required greater amplitude rotations. For the arm/shoulder pain subjects only there was a correlation between degree of slowing and the rating of severity of pain with movement but not the non‐specific pain rating. The hand laterality task may supplement the assessment of subjects with chronic arm/shoulder pain.
Interaction of human immunodeficiency virus gp120 with the voltage‐gated potassium channel BEC1
Authors: Herrmann Madeleine , Ruprecht Klemens , Sauter Marlies , Martinez Javier , van Heteren Pearl , Glas Michael , Best Barbara , Meyerhans Andreas , Roemer Klaus , Mueller-Lantzsch Nikolaus
Published: July 2010

MINT‐7968675: BEC1 (uniprotkb:Q9ULD8) physically interacts (MI:0915) with gp160 (uniprotkb:P04578) by pull down (MI:0096)
Crystal structure of tubulin folding cofactor A from Arabidopsis thaliana and its β‐tubulin binding characterization
Authors: Lu Lu , Nan Jie , Mi Wei , Li Lan-Fen , Wei Chun-Hong , Su Xiao-Dong , Li Yi
Published: July 2010

MINT‐7968928: KIS (uniprotkb:O04350) and Tub9 (uniprotkb:P29517) physically interact (MI:0915) by bimolecular fluorescence complementation (MI:0809)
α‐Synuclein induced cell death in mouse hippocampal (HT22) cells is mediated by nitric oxide‐dependent activation of caspase‐3
Authors: Adamczyk Agata , Kaźmierczak Anna , Czapski Grzegorz Arkadiusz , Strosznajder Joanna Benigna
Published: July 2010

Our previous studies indicated that exogenous α‐synuclein (ASN) activates neuronal nitric oxide (NO) synthase (nNOS) in rat brain slices. The present study, carried out on immortalized hippocampal neuronal cells (HT22), was designed to extend the previous results by showing the molecular pathway of NO‐mediated cell death induced by exogenous ASN. Extracellular ASN (10 μM) was found to stimulate nitric oxide synthase (NOS) and increase caspase‐3 activity in HT22 cells, leading to poly(ADP‐ribose) polymerase (PARP‐1) cleavage. The inhibitor of Ca2+‐dependent NOS (N‐nitro‐l‐arginine, 100 μM) prevented ASN‐evoked caspase‐3 activation and PARP‐1 degradation. ASN exposure resulted in apoptotic death of HT22 cells and this effect was reversed by inhibition of NO synthesis and caspase‐3 activity. Our results demonstrated that extracellular ASN induces neuronal cell death by NO‐mediated caspase‐3 activation.
Glial cells modulate heparan sulfate proteoglycan (HSPG) expression by neuronal precursors during early postnatal cerebellar development
Authors: Araujo Ana Paula B. , Ribeiro Maria Emília O.B. , Ricci Ritchelli , Torquato Ricardo J. , Toma Leny , Porcionatto Marimélia A.
Published: July 2010

Cerebellum controls motor coordination, balance, eye movement, and has been implicated in memory and addiction. As in other parts of the CNS, correct embryonic and postnatal development of the cerebellum is crucial for adequate performance in the adult. Cellular and molecular defects during cerebellar development can lead to severe phenotypes, such as ataxias and tumors. Knowing how the correct development occurs can shed light into the mechanisms of disease. Heparan sulfate proteoglycans are complex molecules present in every higher eukaryotic cells and changes in their level of expression as well as in their structure lead to drastic functional alterations. This work aimed to investigate changes in heparan sulfate proteoglycans expression during cerebellar development that could unveil control mechanisms. Using real time RT‐PCR we evaluated the expression of syndecans, glypicans and modifying enzymes by isolated cerebellar granule cell precursors, and studied the influence of soluble glial factors on the expression of those genes. We evaluated the possible involvement of Runx transcription factors in the response of granule cell precursors to glial factors. Our data show for the first time that cerebellar granule cell precursors express members of the Runx family and that the expression of those genes can also be controlled by glial factors. Our results also show that the expression of all genes studied vary during postnatal development and treatment of precursors with glial factors indicate that the expression of heparan sulfate proteoglycan genes as well as genes encoding heparan sulfate modifying enzymes can be modulated by the microenvironment, reflecting the intricate relations between neuron and glia.
Interference effects in the sum frequency generation spectra of thin organic films. II: Applications to different thin-film systems
Authors: Tong Yujin , Zhao Yanbao , Li Na , Ma Yunsheng , Osawa Masatoshi , Davies Paul B. , Ye Shen
Published: July 2010

In this paper, the results of the modeling calculations carried out for predicting the interference effects expected in the sum frequency generation (SFG) spectra of a specific thin-layer system, described in the accompanying paper, are tested by comparing them with the experimental spectra obtained for a real thin-layer film comprising an organic monolayer/variable thickness dielectric layer/gold substrate. In this system, two contributions to the SFG spectra arise, a resonant contribution from the organic film and a nonresonant contribution from the gold substrate. The modeling calculations are in excellent agreement with the experimental spectra over a wide range of thicknesses and for different polarization combinations. The introduction of another resonant monolayer adjacent to the gold substrate and with the molecules having a reverse orientation has a significant affect on the spectral shapes which is predicted. If a dielectric substrate such as CaF2 is used instead of a gold substrate, only the spectral intensities vary with the film thickness but not the spectral shapes. The counterpropagating beam geometry will change both the thickness dependent spectral shapes and the intensity of different vibrational modes in comparison with a copropagating geometry. The influences of these experimental factors, i.e., the molecular orientational structure in the thin film, the nature of the substrate, and the selected incident beam geometry, on the experimental SFG spectra are quantitatively predicted by the calculations. The thickness effects on the signals from a SFG active monolayer contained in a thin liquid-layer cell of the type frequently used for in situ electrochemical measurements is also discussed. The modeling calculation is also valid for application to other thin-film systems comprising more than two resonant SFG active interfaces by appropriate choice of optical geometries and relevant optical properties.
Determination of the antisymmetric part of the chemical shift anisotropy tensor via spin relaxation in nuclear magnetic resonance
Authors: Paquin Raphaël , Pelupessy Philippe , Duma Luminita , Gervais Christel , Bodenhausen Geoffrey
Published: July 2010

Relaxation processes induced by the antisymmetric part of the chemical shift anisotropy tensor (henceforth called anti-CSA) are usually neglected in NMR relaxation studies. It is shown here that anti-CSA components contribute to longitudinal relaxation rates of the indole N15 nucleus in tryptophan in solution at different magnetic fields and temperatures. To determine the parameters of several models for rotational diffusion and internal dynamics, we measured the longitudinal relaxation rates R1=1/T1 of N15, the N15–H1 dipole-dipole (DD) cross-relaxation rates (Overhauser effects), and the cross-correlated CSA/DD relaxation rates involving the second-rank symmetric part of the CSA tensor of N15 at four magnetic fields B0=9.4, 14.1, 18.8, and 22.3 T (400, 600, 800, and 950 MHz for protons) over a temperature range of 270<T<310 K. A good agreement between experimental and theoretical rates can only be obtained if the CSA tensor is assumed to comprise first-rank antisymmetric (anti-CSA) components. The magnitude of the hitherto neglected antisymmetric components is of the order of 10% of the CSA.
de Sitter breaking through infrared divergences
Authors: Miao S. P. , Tsamis N. C. , Woodard R. P.
Published: July 2010

Just because the propagator of some field obeys a de Sitter invariant equation does not mean it possesses a de Sitter invariant solution. The classic example is the propagator of a massless, minimally coupled scalar. We show that the same thing happens for massive scalars with MS2<0 and for massive transverse vectors with MV2≤−2(D−1)H2, where D is the dimension of space-time and H is the Hubble parameter. Although all masses in these ranges give infrared divergent mode sums, using dimensional regularization (or any other analytic continuation technique) to define the mode sums leads to the incorrect conclusion that de Sitter invariant solutions exist except at discrete values of the masses.
Order-dependent mappings: Strong-coupling behavior from weak-coupling expansions in non-Hermitian theories
Authors: Zinn-Justin Jean , Jentschura Ulrich D.
Published: July 2010

A long time ago, it has been conjectured that a Hamiltonian with a potential of the form x2+ivx3, v real, has a real spectrum. This conjecture has been generalized to a class of the so-called PT symmetric Hamiltonians and some proofs have been given. Here, we show by numerical investigation that the divergent perturbation series can be summed efficiently by an order-dependent mapping (ODM) in the whole complex plane of the coupling parameter v2, and that some information about the location of level-crossing singularities can be obtained in this way. Furthermore, we discuss to which accuracy the strong-coupling limit can be obtained from the initially weak-coupling perturbative expansion, by the ODM summation method. The basic idea of the ODM summation method is the notion of order-dependent “local” disk of convergence and analytic continuation by an ODM of the domain of analyticity augmented by the local disk of convergence onto a circle. In the limit of vanishing local radius of convergence, which is the limit of high transformation order, convergence is demonstrated both by numerical evidence as well as by analytic estimates.
Light direction-dependent plasmonic enhancement in quantum dot infrared photodetectors
Authors: Lee S. C. , Krishna S. , Brueck S. R. J.
Published: July 2010

Plasmonic enhancement of a quantum dot infrared photodetector (QDIP) integrated with a metal photonic crystal (MPC) depends on the direction of the incident light, air-side versus substrate-side illumination. Compared with air-side illumination, substrate-side illumination on the same photodetector results in more than 2× enhancement in detectivity. This is explained by more efficient excitation of surface plasma waves (SPWs) at the MPC/QDIP interface in the back-side geometry. The air/MPC/semiconductor structure is optically asymmetric and has different SPW coupling leading to higher photoresponse for substrate-side illumination. This agrees with simulation and provides direct evidence that the detectivity enhancement is due to the coupling to SPWs and is crucially affected by light incident direction.
Electrospraying insulating liquids via charged nanodrop injection from the Taylor cone of an ionic liquid
Authors: Larriba-Andaluz Carlos , Fernández de la Mora Juan
Published: July 2010

Charge is injected into the bulk of an insulating liquid in the form of nanodrops produced by an immersed Taylor cone of an ionic liquid. The charge then drifts onto the insulator surface, destabilizing it and leading to the formation of an electrified jet that atomizes into approximately monodisperse micron size insulator drops. The approach is similar to those previously based on field injection of ions from sharp tungsten tips, but the continuous renewal and self-sharpening of the liquid charge-injector permits long-term stable operation. Using heptane as the insulator and 1-ethyl-3-methylimidazolium-BF4 as the ionic liquid we produce approximately monodisperse drops with average diameters ranging from less than 4 up to 20 μm, injecting in some cases as little as 0.0002% by volume of ionic liquid. No fundamental limitation restricting the possibility of forming even smaller drops is apparent. The scaling law of Kim and Turnbull [“Generation of charged drops of insulating liquids by electrostatic spraying,” J. Appl. Phys. 47, 1964 (1976)] where the drop diameter varies as the 2/3 power of the liquid flow rate and the −2/3 power of the spray current is confirmed, implying that the drops are on the average charged to 50%–60% of the Rayleigh limit.
On the two-dimensionalization of quasistatic magnetohydrodynamic turbulence
Authors: Favier B. , Godeferd F. S. , Cambon C. , Delache A.
Published: July 2010

We analyze the anisotropy of turbulence in an electrically conducting fluid in the presence of a uniform magnetic field, for low magnetic Reynolds number, using the quasistatic approximation. In the linear limit, the kinetic energy of velocity components normal to the magnetic field decays faster than the kinetic energy of component along the magnetic field [H. K. Moffatt, “On the suppression of turbulence by a uniform magnetic field,” J. Fluid Mech. 28, 571 (1967)]. However, numerous numerical studies predict a different behavior, wherein the final state is characterized by dominant horizontal energy. We investigate the corresponding nonlinear phenomenon using direct numerical simulations. The initial temporal evolution of the decaying flow indicates that the turbulence is very similar to the so-called two-and-a-half-dimensional flow [D. Montgomery and L. Turner, “Two-and-a-half-dimensional magnetohydrodynamic turbulence,” Phys. Fluids 25, 345 (1982)] and we offer an explanation for the dominance of horizontal kinetic energy.
Homogenization and mixing measures for a replenishing passive scalar field
Authors: Keating Shane R. , Kramer Peter R. , Smith K. Shafer
Published: July 2010

The efficiency with which an incompressible flow mixes a passive scalar field that is continuously replenished by a steady source-sink distribution has been quantified using the suppression of the mean scalar variance below the value it would attain in the absence of the stirring. We examine the relationship this mixing measure has to the effective diffusivity obtained from homogenization theory, particularly establishing precise connections in the case of a stirring velocity field that is periodic in space and time and varies on scales much smaller than that of the source. We explore theoretically and numerically via the Childress–Soward family of flows how the mixing measures lose their linkage to the homogenized diffusivity when the velocity and source field do not enjoy scale separation. Some implications for homogenization-based parametrizations of mixing by flows with finite scale separation are discussed.
Mode-specific intermolecular vibrational energy transfer. II. Deuterated water and potassium selenocyanate mixture
Authors: Bian Hongtao , Wen Xiewen , Li Jiebo , Zheng Junrong
Published: July 2010

Vibrational energy transfer from the first excited state (2635 cm−1) of the O–D stretch of deuterated water (D2O) to the 0-1 transition (2075 cm−1) of the CN stretch of potassium selenocyanate (KSeCN) in their 2.5:1 liquid mixture was observed with a multiple-mode two dimensional infrared spectroscopic technique. Despite the big energy mismatch (560 cm−1) between the two modes, the transfer is still very efficient with a time constant of 20 ps. The efficient energy transfer is probably because of the large excitation coupling between the two modes. The coupling is experimentally determined to be 176 cm−1. An approximate analytical equation derived from the Landau–Teller formula is applied to calculate the energy transfer rate with all parameters experimentally determined. The calculation results are qualitatively consistent with the experimental data.
Photocurrent spectra of heavily doped terahertz quantum well photodetectors
Authors: Guo X. G. , Zhang R. , Liu H. C. , SpringThorpe A. J. , Cao J. C.
Published: July 2010

Terahertz (THz) quantum well photodetectors (QWPs) are an important candidate for THz imaging and THz free space communication. Low absorption efficiency of THz QWPs is the main factor limiting the performance of this kind of THz detectors. To increase the absorption efficiency, three heavily doped THz QWPs were fabricated. The band structure calculations show that the second subband falls into the quantum well with increasing Si doping concentration, which decreases the escape probability of the photon-excited electrons in the second subband. This effect is responsible for the blueshift and broadening of the photocurrent peak with increasing Si doping.
Note: New design of a cryogenic linear radio frequency multipole trap
Authors: Asvany Oskar , Bielau Frank , Moratschke Damian , Krause Jürgen , Schlemmer Stephan
Published: July 2010

A new design of a cryogenic linear 22-pole ion trap has been constructed and tested. It is essentially a copper housing to which opposite inner walls two electrode sets are attached via sapphire insulators. These stainless steel electrodes are electroformed in one piece to guarantee good heat conduction. Connected to an external coil, they form an LC-circuit of about 19 MHz resonance frequency. This circuit is excited with a rf power supply made of a commercial digital synthesizer followed by a 10 W amplifier. Buffer gas-cooled H2D+ ions have been stored in this trap at a nominal trap temperature of 14 K. Spectroscopy of the ions confirmed that the kinetic (Doppler) temperature is in reasonable agreement with this value.
Very thin transparent, conductive carbon nanotube films on flexible substrates
Authors: Scardaci Vittorio , Coull Richard , Coleman Jonathan N.
Published: July 2010

We investigate the morphological, electrical, and optical properties of carbon nanotube thin films, focusing on films with transmittance, T>90%. For films with T≈90% we measure sheet resistance of Rs<400 Ω/◻. However, we show that optoelectrical properties, such as σdc and σdc/σOp, degrade with decreasing film thickness, t, for percolating nanotube networks, i.e., those with t<20 nm and T>90%. Thus, while reducing t can give T>99%, the corresponding Rs increases to >40 kΩ/◻. Acid treatment improves the conductivity by doping, giving properties such as T≈98% for Rs≈10 kΩ/◻.