bluuebunny/crossref_metadata_2025 huggingface dataset:
Soil Organic Matter and Nutrient Availability Responses to Reduced Plant Inputs in Shortgrass Steppe
Authors: Kelly Robin H. , Burke Ingrid C. , Lauenroth William K.
Published: May 2006

We examined soil organic matter (SOM) dynamics in a shortgrass steppe ecosystem along spatial gradients in plant inputs and temporal gradients in disturbance age because a better understanding of decay characteristics of SOM pools may improve our ability to predict ecosystem responses to perturbation. We assessed measurable pools of SOM that are thought to correspolnd to active, intermediate, and passive SOM based upon turnover characteristics in three separate experiments. In a first, we evaluated SOM pools along a spatial gradient in plant inputs, from locations under individual bunch grasses to natural areas of plant removal (ant mounds). In a second experiment we assessed SOM pools across a temporal gradient in ant mounds ranging frm $\approx$5 to 60 yr old. Finally, we compared our results from the second experiment to a single human—induced plant removal experiment. We found that reduced root biomass accounted for up to 90% of the variation in SOM across our spatial gradients. In our examination of temporal dynamics of SOM, wer found that locations with little or no plant inputs for $\approx$45 yr had 2% less total soil C than in native areas with average plant cover. We measured the greatest proportional losses (48—78%) of SOM in response to reduced plant inputs (over 30—60 yr) in the active SOM as indexed by C and N mineralization and microbial biomass C and N. The range of losses from intermediate organic matter as indexed by particulate organic matter (POM) ranged from 38 to 73% , and losses from the passive pool were proportionately lower (57%). Though this general pattern flows the course predicted by theory, and our measurements of turnover of intermediate SOM agree closely with models, results indicate a considerably slower turnover rate for the active pool and a considerably faster rate for the passive pool than expected. We compared our field estimates of plant—removal—induced SOM losses to simulation modeling results and cultivation studies. Our comparison of field results to Century model simulations indicated a possible model overesitmation of the impact of plant removal on SOM loss. By comparing our plant—revmoval results to studies of cultivation induced losses of SOM on the shortgrass steppe, we found that plant—removal is not as severe a disturbance as cropping, likely as a result of physical disturbances associated with tillage such as surface erosion and disturbance of soil aggregate structure.
Toward an Integrated Model for Raised‐Bog Development: Theory and Field Evidence
Authors: Almquist‐Jacobson H. , Foster D. R.
Published: May 2006

The development and distribution of Northern mires, including minerotrophic fens and ombrotrophic raised bogs, frequently are presumed to be strongly controlled by the interplay of regional climate and site geomorphology and history. Investigations of these relationships provide insights into long—term trends in ecosystem development by linking geological and landscape—scale processes. In this study, a theoretical model for raised—bog development integrates internal bog hydrodynamics with external factors, including local substrate characteristics, and regional temperature and moisture conditions. The model is used to interpret the development of raised bogs in the Bergslagen region, which coincides with the modern northern distributional limit of those mires in central Sweden. The development of minerotrophic fens that precede bog formation is also considered. Basal radiocarbon dates along surveyed transects are used to assess the pattern and timing of peatland formation and rates of lateral expansion. Previous palynological and lake—level studies from the same region provide independent evidence for changes in Holocene climate. Fen initiation in the region occurred throughout the Holocene under a broad range of environmental conditions. Once established, fens appear to expand faster during moister periods. Locally, substrate slope is an important mediator of fen development, with slopes >0.5% inhibiting lateral expansion. Accumulation of Sphagnum peat, an indicator of raised—bog initiation, occurred from ≈ 4000 to 5000 yr BP during relatively dry phases. Rates of lateral expansion were not significantly affected by increasing moisture or by decreasing temperatures until at least 2000 yr BP. However, modern geographic trends in cross—sectional shape of mires suggest that, at the northern limit of their range today, raised bogs are limited by low temperatures.
Seed Size of Woody Plants in Relation to Disturbance, Dispersal, Soil Type in Wet Neotropical Forests
Authors: Hammond D. S. , Brown V. K.
Published: May 2006

Fresh and dry masses of seeds of woody species collected at Mabura Hill, Guyana were evaluated according to dispersal mode, gap size preference, and soil type. Data published for woody species from Manu, Peru and Barro Colorado Island (BCI), Panama were analyzed by dispersal mode and gap size preference for comparison. Larger seeds at the three sites were significantly associated with canopy or emergent trees or lianas that are dispersed by mammals or gravity and recruit best in small gaps. Variation in seed size, after accounting for the effects of plant height and life—form, could be explained by dispersal mode (Mabura Hill: 22%, Manu: 14%, BCI: 26%) and gap size preference (Mabura Hill: 9%, Manu: 7%, BCI: 11%). Soil type preference, analyzed only for Mabura Hill, was not associated with seed size. Mean seed size at Mabura Hill was significantly larger than at Manu or BCI. Short—term successional processes may explain the variation of seed size within sites; dispersal mode is particularly important in defining seed size selection during the successional process. However, short—term successional processes cannot explain the variation of seed size among sites. It is suggested that this variation may be attributed to differences in the effects of larger—scale variations in soils and disturbance on seed size among the three sites.
Ficus Stupenda Germination and Seedling Establishment in a Bornean Rain Forest Canopy
Authors: Laman Timothy G.
Published: May 2006

Factors limiting seed germination and seedling establishment of the hemiepiphyte Ficus stupenda were investigated with two field experiments conducted in a Bornean rain forest canopy. In Experiment 1, seeds of F. stupenda were planted in potential establishment sites averaging 31 m above the ground in each of 45 dipterocarp trees. Twenty seeds each were planted in a total of 336 sites. Germination, survivorship, and growth were monitored over 1 yr, and examined in relation to microsite and host tree characteristics. The presence of substrate with good moisture retention (soil, rotting wood, or moss) was the most important factor for germination. Such substrates were most frequently associated with knothole sites in the canopy, which had the highest level of establishment success. Seedling survival to 12 mo was low (1.3% of planted seeds), especially considering that the best available sites in each tree were selected. Only 0.04% of seedlings showed vigorous growth after 12 mo. A seed—harvesting ant in the genus Pheidole significantly reduced germination success, and herbivory and desiccation killed many seedlings at later stages. In Experiment 2, seedling growth in natural canopy sites was compared with growth of seedlings in artificial planter boxes raised into the canopy in order to assess the relative quality of canopy sites. Planters were superior to natural sites for seedling survivorship and supported much more rapid seedling growth with a positive response to light level. Higher growth rates in planters compared with natural sites showed that water stress appeared to be the critical factor limiting seedling growth in the canopy, even in this very wet climate. Sites in the canopy with the optimal combination of conditions for fig seedling establishment appear to be very scarce. Ficus population densities may be limited by both biotic and abiotic factors reducing early recruitment success.
Responses of Legumes to Herbivores and Nutrients During Succession on a Nitrogen‐Poor Soil
Authors: Ritchie Mark E. , Tilman David
Published: May 2006

We measured legume abundance following 13— and 5—yr experiments testing for the effects of mammalian herbivores, nutrients, and climate on plant communities in an old field and a savanna in east central Minnesota. Total legume abundance was significantly greater in plots with herbivores excluded. Within herbivore exclosures, legumes were more abundant in plots to which P, K, S, Mg, Mn, Ca, Na, and trace minerals had been added. Legumes were significantly more abundant in the savanna than in the old field. Lathyrus venosus, a rapidly growing early—maturing species, was largely responsible for these results. Two other common legumes at our study site, Amorpha canescens and Lespedeza capitata, were not significantly affected by herbivore exclosures. However, within herbivore exclosures, addition of nutrients significantly reduced Lespedeza. Late summer total legume biomass within herbivore exclosures increased strongly following exclosure establishment in 1982, declined dramatically following a severe drought in 1988, and then increased again following the drought. This trend suggested that herbivore effects we measured in 1994 resulted from long—term accumulation of legumes following the establishment of exclosures. Our results suggest that herbivores and nutrients other than nitrogen can dramatically limit the abundance of some legume species that might otherwise dominate grassland plant communities on nitrogen—poor soils. Limitation of legumes by colonization and drought may also be important. Thus, herbivores and nutrients other than nitrogen may be critical in structuring grassland plant communities and influencing succession, even on nitrogen—poor soils.
Body Size Variation in Lesser Snow Geese: Environmental Plasticity in Gosling Growth Rates
Authors: Cooch E. G. , Lank D. B. , Dzubin A. , Rockwell R. F. , Cooke F.
Published: May 2006

We examined the influence of timing of reproduction and brood size on growth rates of goslings of nidifugous Lesser Snow Geese (Anser caerulescens) using data collected at La Perouse Bay, Manitoba from 1978 to the present, Gosling growth rates declined significantly during the season, and the declines were independent of the parental genotype. Goslings from larger broods grew significantly faster, but there was no significant annual variation in the seasonal growth rate patterns with either hatch date or brood size. The hatch date and brood size effects could not be accounted for by systematic differences in either egg size or body size of the female parent. Goslings that grew more slowly due to the effects of hatch date or brood size were significantly smaller as adults. Because gosling growth rates influence final adult size, they may have a significant effect on various life history traits in this species.
Experimental Determination of Seed Bank Age Structure in the Winter Annual Collinsia Verna
Authors: Kalisz Susan
Published: May 2006

Data on survival in and emergence from soil seed banks are scarce for natural plant populations. In this paper I present a new experimental method for quantifying soil seed bank dynamics in the field and data derived from this method describing the age structure of the seed bank for the winter annual Collinsia verna. The roles of spatial and temporal variation in seed bank formation were investigated using a replicated design arrayed along three transects in the study site. Emergence from and persistence in the seed bank were monitored for 3 yr using experimental seed banks containing seeds of the same age arrayed along each of the three transects. In addition, replicate estimates of survivorship and fecundity of naturally emerging plants were monitored in quadrats arrayed along each of the three transects. The conditional probability of persisting in the seed bank for 1 yr ranged from 14 to 45% and differed significantly among the transects. Significant differences in the probabilities of emerging (or persisting) produced seed banks of varying age structure among the transects and years. A life table analysis of the vegetative plants indicated significant differences between years in their survivorship curves. In addition, seedlings derived from seeds 1 yr old or older germinated significantly later than the general seed population. Age—structured seed banks are expected to alter the population dynamics and demographic projections of plant populations.
The film boiling reactor: A new environment for chemical processing
Authors: Urban Bryan J. , Avedisian C. Thomas , Tsang Wing
Published: May 2006

A new platform, based on film boiling, is described for chemical processing by catalytic decomposition of organic liquids. A model for conversion of pure methanol to hydrogen and carbon monoxide is used to illustrate the operational and performance characteristics of the reactor. The model extends film boiling theory to include catalytic reactions at the surface. The results show that wall temperature exerts a dominant influence on product yields, with tube diameter a secondary effect. The yields of hydrogen increase as tube diameter and wall temperature increase, with the variation being nonlinear. At temperatures > 1200 K, the wall conversion rates reach an asymptote with wall concentrations of hydrogen and carbon monoxide being lower and higher than stoichiometric, respectively, because of the higher diffusion rate of hydrogen compared to carbon monoxide. A dimensional “performance factor,” defined as the ratio of hydrogen yield to the total energy required to maintain the vapor film and drive the reaction, is used to cast the performance of the film boiling reactor in terms of the variables of the problem. For the range of tube diameters examined (1.5 mm to 1.5 cm), the analysis shows the existence of wall temperatures that optimize performance. The advantages of the new reactor system are its simplicity and potentially large product yields, making it ideal for portable applications. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Formation of galacto‐oligosaccharides during lactose hydrolysis by a novel β‐galactosidase from the moderately thermophilic fungusTalaromyces thermophilus
Authors: Nakkharat Phimchanok , Kulbe Klaus D. , Yamabhai Montarop , Haltrich Dietmar
Published: May 2006

Discontinuous and continuous processes of lactose hydrolysis and concomitant galacto‐oligosaccharide (GalOS) formation were studied. To this end a wide experimental range of the main variables was evaluated, including the initial lactose concentration, the degree of lactose conversion, the pH value and the temperature for discontinuous transformations, while the initial lactose concentration and the feed rate were varied for the continuous process. For both processes a high‐initial lactose concentration proved to be advantageous for the formation of GalOS. The maximum amount of GalOS (100 g/L, corresponding to a yield of approximately 50% based on the initially employed lactose) was obtained after 8 h of incubation when using 200 g/L lactose as substrate and 90% lactose hydrolysis was observed. GalOS productivity in the continuous process (g/L·h) was enhanced by an increase of the flow rate. The maximum GalOS productivity of 70 g/L·h was obtained at a flow rate of 24 mL/h when using a reactor with a total working volume of 21 mL. As was evident from these experiments, this β‐galactosidase from a moderately thermophilic fungus showed a strong transgalactosylation activity and can be used for the formation of GalOS, sugars that are of considerable interest for functional food applications because of their presumed healthpromoting effects.
Study on the Photochromism of Ni–Al Layered Double Hydroxides Containing Nitrate Anions
Authors: Wei Min , Xu Xiangyu , Wang Xinrui , Li Feng , Zhang Hui , Lu Yanluo , Pu Min , Evans David G. , Duan Xue
Published: May 2006

The photochromism of nitrate‐containing nickel–aluminum layered double hydroxides (NiAl‐NO3‐LDHs) has been studied. Powder X‐ray diffraction (PXRD), FTIR, UV/Vis, XPS, ESR, EXAFS, and elemental analysis were used to investigate the structure, composition, and photochromic behavior of NiAl‐NO3‐LDHs. A possible photochromic mechanism in NiAl‐NO3‐LDHs has been proposed.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Ad hoc on demand multipath distance vector routing (AOMDV) over a distributed TDMA MAC protocol for QoS support in wireless ad hoc networks: integration issues and performance evaluation
Authors: Loscrì Valeria , De Rango Floriano , Marano Salvatore
Published: May 2006

This paper focuses on the problem of QoS multi‐path in wireless ad hoc networks. An integration of a novel multi‐path routing protocol and a distributed time division multiple access (TDMA) MAC protocol is proposed. The MAC considered is called evolutionary TDMA (E‐TDMA) and the analysed multi‐path routing protocol is the ad hoc on demand multi‐path distance vector (AOMDV) protocol. The integrated approach multi‐path routing and TDMA MAC protocol offers advantages typical of multi‐path routing, in terms of reduced route discovery frequency and increased throughput. The advantage of the E‐TDMA MAC is a higher throughput in comparison with the standard IEEE 802.11 MAC and the reduction of the contention interference due to the slot reservation mechanism for high‐data traffic. Two schemes to build the multi‐route are exploited. The simulation results show the benefits of the integrated routing‐MAC protocol in terms of reduced overhead, higher throughput and reduced end‐to‐end delay for a scenario with very high mobility and heavy data traffic. Copyright © 2006 AEIT
Controlled Degradation of Poly(propylene) in Industrial Extruders
Authors: Oliveira Jackson A. , Biscaia Evaristo C. , Fadigas José C. S. , Pinto José C.
Published: May 2006

Summary: The main objective of this work was to study the controlled degradation of PP in industrial extruders at different operating conditions. Firstly, the investigation of certain key polymer properties, such as the MI and the MWD, revealed that the changes undergone by the polymer resin during the reactive extrusion depend strongly on the operating conditions. In the absence of oxygen, the results indicated that spontaneous thermal and/or mechanical degradation were not very important. Therefore, resin properties were not expected to change during extrusion if no peroxide was fed into the extruder, in the absence of oxygen. On the other hand, in the presence of oxygen, MWD analysis showed that the MWD could be shifted towards higher or lower molecular weights, indicating that both chain growth and chain scission were possible during extrusion. Finally, simple expressions are presented here in order to allow for the monitoring and control of the important final properties of the extruded resin.

The molecular weight distribution of polymer powder and polymer pellets during extrusion.

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The molecular weight distribution of polymer powder and polymer pellets during extrusion.
Role of the leader sequence in tobacco pectin methylesterase secretion
Authors: Dorokhov Yuri L. , Skurat Eugene V. , Frolova Olga Yu. , Gasanova Tatjana V. , Ivanov Peter A. , Ravin Nikolay V. , Skryabin Konstantin G. , Mäkinen Kristiina M. , Klimyuk Viktor I. , Gleba Yuri Yu. , Atabekov Joseph G.
Published: May 2006

We report that unprocessed tobacco pectin methylesterase (PME) contains N‐terminal pro‐sequence including the transmembrane (TM) domain and spacer segment preceding the mature PME. The mature portion of PME was replaced by green fluorescent protein (GFP) gene and various deletion mutants of pro‐sequence fused to GFP were cloned into binary vectors and agroinjected in Nicotiana benthamiana leaves. The PME pro‐sequence delivered GFP to the cell wall (CW). We showed that a transient binding of PME TM domain to endoplasmic reticulum membranes occurs upon its transport to CW. The CW targeting was abolished by various deletions in the TM domain, i.e., anchor domain was essential for secretion of GFP to CW. By contrast, even entire deletion of the spacer segment had no influence on GFP targeting.
Last glacial cycle hydrological change at Lake Tyrrell, southeast Australia
Authors: Stone Tim
Published: May 2006

Lake Tyrrell is the largest playa in the Murray Basin of southeast Australia. Optical dating of transverse dune (lunette) sediments extends the lake's radiocarbon chronology to the last interglacial period. The highest lake level was attained 131,000 ± 10,000 yr ago, forming Lake Chillingollah, a megalake that persisted until around 77,000 ± 4000 yr ago. Pedogenesis of its sandy lunette continued until buried by a silty clay lunette deflated from the lake floor 27,000 ± 2000 yr ago. The dated soil-stratigraphic units correlate with the upper Tyrrell Beds and contain evidence that humans visited the lakeshore before 27,000 yr ago. The Lake Chillingollah megalake was synchronous with very high lake levels in monsoon-dominated Australia, yet it was not influenced by tropical monsoon systems. It was filled instead by increased winter rainfall from westerly low-pressure fronts. Greater effective precipitation across Australia is evident, the result of a weakened subtropical high-pressure zone.
Instrumental music? The social origins of broadcast music in British factories
Authors: KORCZYNSKI MAREK , JONES KEITH
Published: May 2006

This paper explores the social origins and development of music relayed through loudspeakers in British factories during World War Two, focusing on the BBC programme Music While You Work, which provided a national soundtrack for factory work, and the contemporary institutions of Industrial Psychology, which promoted music as a highly ‘valuable’ accompaniment to work and formulated scientific principles governing its broadcast. Combining archival evidence from these organisations, the paper first outlines the historical circumstances of development, detailing the form of broadcasts and of the music itself. Subsequently, the causes of music's introduction to the factory are analysed. The central argument advanced is that the music resulted centrally from top-down initiatives from a ‘human relations school’ coalition of institutions and individuals, in which the aims of increased productivity and the humanisation of the workplace intermingled, but in which the aim of increased productivity dominated. Concluding remarks assess the argument and relate it to the growing literature on contemporary practices of the sound-tracking of social life.
Chemistry of vent fluids and its implications for subsurface conditions at Sea Cliff hydrothermal field, Gorda Ridge
Authors: Von Damm K. L. , Parker C. M. , Lilley M. D. , Clague D. A. , Zierenberg R. A. , Olson E. J. , McClain J. S.
Published: May 2006

We report here the first compositional data for fluids from the Sea Cliff hydrothermal field, northern Gorda Ridge, collected in 2000, 2002, and 2004. An unusual aspect of this site is its location ∼2.6 km east of the axis of spreading, leading to speculation since its discovery in 1988 that this may be an “older” hydrothermal field, as it occurs on crust that the spreading rate would predict to be ∼100,000 years old. Our results suggest this hydrothermal system is being driven by subsurface magma, as evidenced by (1) elevated 3He/heat ratios, (2) relatively high concentrations of He, and (3) chloride contents less than seawater in the hydrothermal fluids. The measured fluid temperatures were ≤308°C, but we infer they were >400°C at depth. In spite of these elevated temperatures, the fluids exiting from these vents are clear, a consequence of extremely low transition metal concentrations. We attribute the low transition metal contents to loss of these metals below the seafloor, most likely as a result of the slightly elevated pH of the fluids. Neither the fluid compositions nor the setting provides evidence that buried sediments and/or organic matter are responsible for raising the fluid pH. Our favored explanation for the elevated pH is that calcite, deposited as a vein‐filling mineral at this site, perhaps when it was closer to the axis and a hydrothermal downflow zone, is currently being dissolved by the hydrothermal fluids. This hypothesis is supported by our geochemical modeling results that suggest the fluids are close to saturation with calcite at in situ conditions. Elevated fluid pH is observed at a number of hydrothermal sites on the global mid‐ocean ridge system, and the reason for this has not been well understood. Dissolution of previously deposited calcite may be a heretofore unrecognized mechanism that can explain these observations. Finally, our data suggest the compositions of these fluids are unchanged from 2002 to 2004 and are consistent with water column observations first made at this site in 1985. We therefore interpret the Sea Cliff site to be another hydrothermal area marked by long‐term stability in fluid compositions and temperatures.
Kinetic properties of heavy solar wind ions from Ulysses‐SWICS
Authors: von Steiger R. , Zurbuchen T. H.
Published: May 2006

The kinetic properties of heavy ions in the solar wind reflect the plasma processes governing the solar wind in the heliosphere. We use Ulysses‐SWICS data that resolve heavy ions in a wide range of mass‐per‐charge values, 2 ≤ m/q ≤ 9.33, to investigate the heavy ions and their dynamic evolution throughout the heliosphere. While at 1 AU the imprint of Coulomb collisions is known to be present in the slow solar wind, we show that is vanishes by the time the wind has reached 5 AU. All ion species flow with equal bulk and thermal speeds there. This is interpreted as a progressive dominance of wave‐particle interactions over Coulomb collisions.
Detailed imaging of tectonic structures by multiscale Earth resistivity tomographies: The Colfiorito normal faults (central Italy)
Authors: Diaferia I. , Barchi M. , Loddo M. , Schiavone D. , Siniscalchi A.
Published: May 2006

This study is aimed to show how cost effective geophysical surveying, integrated with detailed knowledge of the local geology, can give a significant contribution to image the subsurface structure of complex areas of active faulting. The combined inversion of a data set consisting of a large scale tomography and a target‐dependent multiresolution dipole‐dipole measurements, the multiscale approach, is shown to yield detailed structural information and to infer some characteristics of the fault zone. The operating procedure, applied to the Colfiorito fault system, allowed to differentiate the electrical signatures of the crossed faults. Minor faults show sharp lateral variations generated by a contact between different geological formations, while the major faults are also characterized by a decrease in resistivity values distributed on the fault damage zones. A close interpretation was supported by detailed geological surface data. Besides, quantitative correlations between in situ resistivity distribution and geological units were supported by electrical logs.
Monitoring the chemical vapor deposition growth of multiwalled carbon nanotubes by tapered element oscillating microbalance
Authors: Švrček V. , Kleps I. , Cracioniou F. , Paillaud J. L. , Dintzer T. , Louis B. , Begin D. , Pham-Huu C. , Ledoux M.-J. , Le Normand F.
Published: May 2006

The growth of multiwalled carbon nanotubes (MWCNTs) produced by a catalytic chemical vapor deposition (CCVD) process has been monitored using a tapered element oscillating microbalance (TEOM) probe. This technique displays a high sensitivity (<1μg). Growths in the TEOM microreactor are investigated with catalytic particles (Fe, Ni) dispersed on different supports. First, high surface area Fe∕Al2O3 or Fe (Ni) exchanged on zeolite powders is used. Second, growths are performed on array of nickel dots or Fe∕Si-nc particles dispersed on large holes patterned on Si(100) substrates. An accurate monitoring of the early stages of growth permits a precise evaluation of the growth rates and shows substantial differences between these samples which greatly differ by the surface area. On catalysts dispersed on Si(100) the mass uptake is linear throughout the process. On high surface area catalysts, however, a saturation of the mass uptake is indifferently observed. This saturation is explained either by diffusion limitation by the growing MWCNTs or by internal diffusion through the pores or external diffusion through the grains of the catalyst. The kinetic dependence with partial pressure of the incoming C2H6:H2 gas mixture is then explored on the Fe∕Al2O3 catalyst. A linear dependence of the MWCNT growth an (PC2H6∕PH2)1∕2 is found. A simple model is then developed that accounts for this dependence only if an associative and competitive adsorption of ethane is the rate determining step of the overall process. These results thus bring insight to improve and control the CCVD growth kinetics of MWCNTs.
Metastability of CuInS2 and its implications on thin-film growth
Authors: Hahn Thomas , Cieslak Janko , Metzner Heinrich , Eberhardt Jens , Reislöhner Udo , Gossla Mario , Witthuhn Wolfgang , Kräußlich Jürgen
Published: May 2006

Thin layers of the ternary chalcopyrite semiconductor CuInS2 grown epitaxially on Si(001) substrates were investigated with respect to the existing phases and their lattice parameters by means of x-ray diffraction at the European Synchrotron Radiation Facility in Grenoble (France). The predominant parts of the samples exhibit the metastable CuAu-type ordering. The smaller volume fractions of the samples showing the ground-state chalcopyrite ordering are distorted in order to accommodate themselves to the tetragonal CuAu-type structure. It is suggested that this finding is a consequence of the growth mode of CuInS2 thin films.
Orientation-dependent grain growth in a bulk nanocrystalline alloy during the uniaxial compressive deformation
Authors: Fan G. J. , Wang Y. D. , Fu L. F. , Choo H. , Liaw P. K. , Ren Y. , Browning N. D.
Published: May 2006

The microstructural evolution during the uniaxial compression of an as-deposited bulk nanocrystalline (nc) Ni–Fe (average grain size d≈23nm) at ambient temperature was investigated by the high-energy x-ray diffraction (HEXRD) and the transmission-electron microscopy (TEM). HEXRD measurements indicated that the grain growth occurred in the nc Ni–Fe alloy during the uniaxial compression tests and that the grain growth shows orientation dependence, i.e., the grains preferentially grow perpendicular to the loading direction. This preferred grain growth was further confirmed by the TEM observations, indicating that the grains were elongated after the compressive plastic deformation.
GaN full-vertical p-i-n rectifiers employing AlGaN:Si conducting buffer layers on n-SiC substrates
Authors: Yoo D. , Limb J. , Ryou J.-H. , Lee W. , Dupuis R. D.
Published: May 2006

The development of a full-vertical GaN p-i-n rectifier on a 6H n-type SiC substrate by employing a conducting AlxGa1−xN:Si (x=∼0.1) buffer layer scheme is reported. In this vertical configuration, the n contact is made on the backside of the SiC substrate using a Ni∕Au metallization scheme. Epitaxial layers are grown by low-pressure metal organic chemical vapor deposition. The AlxGa1−xN:Si nucleation layer is proven to provide excellent electrical properties while also acting as a good buffer layer for subsequent GaN growth. The reverse breakdown voltage for a relatively thin 2.5μm thick i region was found to be over −330V. The devices also show a low on resistance of Ron of 7.5×10−3Ωcm2. This full-vertical configuration provides the advantage of the reduction of sidewall damage from plasma etching and lower forward resistance due to the reduction of current crowding in the bottom n-type layer.
A model of acquired autoresistance to a potent ErbB2 tyrosine kinase inhibitor and a therapeutic strategy to prevent its onset in breast cancer
Authors: Xia Wenle , Bacus Sarah , Hegde Priti , Husain Intisar , Strum Jay , Liu Leihua , Paulazzo Georgina , Lyass Ljuba , Trusk Patricia , Hill Jason , Harris Jennifer , Spector Neil L.
Published: May 2006

The development of acquired resistance to ErbB2 tyrosine kinase inhibitors limits the clinical efficacy of this class of cancer therapeutics. Little is known about the mechanism(s) of acquired resistance to these agents. Here we establish a model of acquired resistance to
N
-{3-chloro-4-[(3-fluorobenzyl) oxy]phenyl}-6-[5-({[2 (methylsulfonyl)ethyl]amino}methyl)-2-furyl]-4-quinazolinamine (lapatinib), an inhibitor of ErbB2 and ErbB1 tyrosine kinases by chronically exposing lapatinib-sensitive ErbB2-overexpressing breast cancer cells to lapatinib, simulating the clinic where lapatinib is administered on a daily chronic basis. Analysis of baseline gene expression in acquired lapatinib-resistant and parental cells indicates estrogen receptor (ER) signaling involvement in the development of resistance. Using gene interference, we confirm that acquired resistance to lapatinib is mediated by a switch in cell survival dependence and regulation of a key antiapoptotic mediator from ErbB2 alone to codependence upon ER and ErbB2 rather than loss of ErbB2 expression or insensitivity of ErbB2 signaling to lapatinib. Increased ER signaling in response to lapatinib is enhanced by the activation of factors facilitating the transcriptional activity of ER, notably FOXO3a and caveolin-1. Importantly, we confirm that lapatinib induces ER signaling in tumor biopsies from patients with ErbB2-overexpressing breast cancers receiving lapatinib therapy. These findings provided the rationale for preventing the development of acquired resistance by simultaneously inhibiting both ER and ErbB2 signaling pathways. Establishing clinically relevant models of acquired resistance to ErbB2 kinase inhibitors will enhance therapeutic strategies to improve clinical outcomes for patients with ErbB2-overexpressing breast cancers.
Cloning, expression and location of the RNA-dependent RNA polymerase gene fromBombyx mori cypovirus 1
Authors: Jing-Chen Sun , Wei-Jun Dai , Yu-Rong Tan , Yi-Feng Yang , Qin-Fen Zhang , Xing-Yao Xu , Jing-Qiang Zhang
Published: May 2006

The RNA-dependent RNA polymerase (RdRp) gene ofBombyx mori cypovirus 1(BmCPV-1) (China strain) was cloned in three fragments using step-by-step reverse transcriptase-polymerase chain reaction (RT-PCR). The wholeRdRpgene of 3691 bp was sequenced (GenBank accession number: AY496445). Vector pET-28b(+) was used to construct the expression vector pET28b–RdRpwhich was expressed inEscherichia coliBL21 (DE3) induced with isopropyl β-d-thiogalactoside (IPTG). The molecular weight of the expression product was about 138 Da. The primary antibody employed was rabbit antibody against BmCPV–RdRp recombinant protein and the secondary antibody was 15 nm immunogold-labelled goat anti-rabbit IgG. Immunogold was mostly bound to the virions which were dispersed in a virus generation matrix and polyhedron in the columnar cells of the midgut of the silkworms, and the average marking ratio was about 35%. This result demonstrated that BmCPV–RdRp complexes are indeed located at the BmCPV capsid.
Does diet have a role in the aetiology of rheumatoid arthritis?
Authors: Pattison Dorothy J. , Symmons Deborah P. M. , Young Adam
Published: May 2006

Although dietary factors have been extensively studied in many chronic diseases, the role of diet in the epidemiology of rheumatoid arthritis (RA) has received little attention. Fruit and vegetables and dietary antioxidants are thought to play a protective role in the pathogenesis of CVD and some cancers, but few studies have investigated these dietary components in the aetiology of RA. Fish oil supplementation has consistently been shown to have a beneficial effect on the symptoms of established RA, but it is not known whether the PUFA present in fish oils can reduce the risk of developing the disease. There is evidence that RA is less severe in the southern Mediterranean countries, such as Italy and Greece, where oil-rich fish, fruit, vegetables and olive oil are consumed in greater amounts than in many other countries. Overall, the evidence for a role of diet in the aetiology of RA is limited to a small number of observational studies of very different designs. Recently, it was demonstrated that lower intakes of fruit and vegetables and dietary vitamin C are associated with an increased risk of developing inflammatory polyarthritis in a free-living population in Norfolk, UK. These findings provide further evidence for a role of diet in the development of inflammatory arthritis, although the mechanisms involved are uncertain.
PACK: Profile Analysis using Clustering and Kurtosis to find molecular classifiers in cancer
Authors: Teschendorff Andrew E. , Naderi Ali , Barbosa-Morais Nuno L. , Caldas Carlos
Published: May 2006

Motivation: Elucidating the molecular taxonomy of cancers and finding biological and clinical markers from microarray experiments is problematic due to the large number of variables being measured. Feature selection methods that can identify relevant classifiers or that can remove likely false positives prior to supervised analysis are therefore desirable.

Results: We present a novel feature selection procedure based on a mixture model and a non-gaussianity measure of a gene's expression profile. The method can be used to find genes that define either small outlier subgroups or major subdivisions, depending on the sign of kurtosis. The method can also be used as a filtering step, prior to supervised analysis, in order to reduce the false discovery rate. We validate our methodology using six independent datasets by rediscovering major classifiers in ER negative and ER positive breast cancer and in prostate cancer. Furthermore, our method finds two novel subtypes within the basal subgroup of ER negative breast tumours, associated with apoptotic and immune response functions respectively, and with statistically different clinical outcome.

Availability: An R-function pack that implements the methods used here has been added to vabayelMix, available from ().

Contact:  aet21@cam.ac.uk

Supplementary information: Supplementary information is available at Bioinformatics online.
Making Sense of the Infant Formula Controversy
Authors: Paine Heather
Published: May 2006

The main features of the UK Code of Practice for the Marketing of
Infant Formula and the reasons behind its development are briefly
described. The criticisms of the industry′s marketing practices are
addressed and arguments against these criticisms are put forward.
Developments in the EEC are also discussed, with the implications for
the UK. It is concluded that the UK needs a sensible approach to
legislation, that will allow the promotion of infant milks while at the
same time protecting the rights of breast and bottle‐feeding mothers.
Microbiological Safety – The Role of the Institute of Food Research
Authors: Moseley B.E.B.
Published: May 2006

Enormous changes have taken place in the manufacture, production
and distribution of food in the recent past. With this in mind, the food
industry and government must be ever‐vigilant about safety, because
these changes in methods can result in unlooked‐for changes elsewhere in
the chain. Relevant scientific research being conducted at the AFRC
Institute of Food Research is described.
Salmonellosis
Authors: Sharp J.C.M.
Published: May 2006

During and immediately after the Second World War salmonellosis
first emerged as a public health problem in Britain, having been
introduced primarily via contaminated batches of dried egg from the USA.
Surveys of broiler carcasses at retail outlets and hospitals have shown
salmonella contamination rates varying between 45 and 80 per cent. To
what extent the legislative control measures introduced during 1989
requiring the testing and slaughter of infected laying and breeding
poultry flocks, more frequent inspection of protein processing plants,
along with other veterinary measures, will be effective in controlling
salmonellosis and other foodborne infections in Britain, remains to be
seen. In 1989 the government also announced its intention to introduce
legislation which will legalise the use of irradiation of certain foods,
including poultry, the cost‐effectiveness of which as a public health
measure has been demonstrated.
The Development of an EC Policy on Food Safety and Quality
Authors: Allen Paul
Published: May 2006

East Sussex County Council has been invited to allow their Trading
Standards Officer to help the European Commission implement the Official
Control of Foodstuffs Directive. The author′s views on the Directive are
presented.
Food Research Strategy and Requirements: 1992‐94
Authors: Fallows Stephen J.
Published: May 2006

A strategy document which reflects many of the most prominent food
issues of recent years has been published by the Ministry of
Agriculture, Fisheries and Food. Many of its aims are discussed
including research and programme management and also the protection of
the public by ensuring food safety within an efficient industry.
A Web of Sound: The Charles Parker Archive
Authors: Tait Fiona
Published: May 2006

A description is given of the Charles Parker Archive in Birmingham
Reference Library. The background of Charles Parker and his work in the
BBC and in the folk revival are described. Production of The Radio
Ballads and later work is mentioned. The contents and subject matter
of the Archive, its cataloguing and the promotion of such oral history
material are discussed.
The Management of Change in a Library Service
Authors: Odini Cephas
Published: May 2006

The psychological, communication, motivational and administrative
factors which require attention in the management of change in library
services are all examined. The importance of change, particularly in
relation to progress in service provision, is emphasised. The selection
of change management strategies to minimise hardship in staff
administration and to ensure effective implementation and staff
commitment is considered.
What Will Be Might Be: Some Thoughts on Likelihood in
Libraries
Authors: Hannabuss Stuart
Published: May 2006

Some aspects of statistical probability and forecasting are
considered in relation to library planning. Some aspects of library
management and decision making are discussed in the light of this theory
of probability.
The Library of Rhodes House, Oxford
Authors: Howard Jeanne G.
Published: May 2006

The career of Cecil John Rhodes is described, leading to the establishment by his bequest of the Rhodes Scholarship programme. The building of Rhodes House at Oxford is described and an account given of the library established in it and the development of its collections into one of the world′s finest repositories of British colonial history.
Greek, Computers and Libraries
Authors: Cornell Evelyn
Published: May 2006

The provision of classical and biblical texts on CD‐ROM databases
and their use in King′s College Library are reviewed. A project is
described to catalogue by the Libertas system a collection of
Modern Greek literature in collaboration with the University of Crete.
Cataloguing and transliteration problems are discussed.
The Early Staffing of the London Library: A Note on John
George Cochrane and Others
Authors: Baker William
Published: May 2006

The candidates for the post of first librarian of the London
Library are considered and the circumstances involved in the appointment
of John George Cochrane are discussed. Cochrane′s immediate successors
are briefly reviewed, as well as the overall staffing of the Library in
the mid‐nineteenth century.
A Structured Approach to Residential Workshop Organisation
Authors: McElwee Gerard
Published: May 2006

This article demonstrates how training agencies
and other business institutions could follow
the lead of Teesside Business School by reviewing
their residential seminars and “in‐house” workshops.
Such residential courses, it is argued, can be
further enhanced as a learning exercise by
refining and critically assessing current evaluation
systems. At Teesside this was done using the BA
(Hons) Business Studies degree as a model. The
theoretical framework for reviewing some of
these practical issues is provided by utilising a
structured approach to systems analysis. This
approach produces a more appropriate model
than those used in many current systems.
Meeting the Needs of Employers
Authors: Pollitt David
Published: May 2006

A description is given of the Professional,
Industrial and Commercial Updating (PICKUP)
Europe Unit, operated by a consortium
consisting of Bradford University, South Bank
Polytechnic, Leeds Polytechnic and Spicers
Centre for Europe, which will offer employers
“one‐stop shopping” where they can obtain
advice, consultancy and short courses. An initial
network of 20 Regional Centres is being
established to gather market intelligence, identify
development needs and highlight good practice.
Appropriate research will be commissioned and
the results disseminated in a variety of ways.
Broad outlines of the training implications of the
Single Market are identifed. These range from
the knowledge of legislation relating to the
market itself to the likely effects on manpower
planning. The need for a response from
educationists is emphasised, as transnational
study programmes, aided by distance learning
methods and satellite and computer links, grow
in importance.
The Modern Languages in Industry Project: Putting Languages to Work for TVEI
Authors: Dunning Lesley
Published: May 2006

A project is described which involved liaising with
companies to research current use and future needs
of foreign languages. Twenty‐four schools
participated. A materials development team of
teachers was formed who visited various
organisations to investigate their use of foreign
languages. Their aim was to provide a local
business context for foreign language learning.
Wherever possible, self‐study materials were to be
provided and IT applications included. A
description is given of the workpacks completed in
collaboration with a number of organisations.
Where do Students Figure in your EHE Equation? The Development of the Role and Function of a Student Enterprise Manager
Authors: Hursey Tony , Taylor Maggie
Published: May 2006

The authors describe the development of the role and function of a
Student Enterprise Manager under the Enterprise in Higher Education
Initiative. Chester College of Higher Education was the first
institution to adopt a “management model” rather than
“representative model” of student involvement in their EHE
programme. The article discusses processes of consultation, recruitment
and selection which engaged students in the appointment of one of their
own Graduates to the first, sabbatical post of Student Enterprise
Manager. The authors summarise the problems and approaches to creating a
totally new role and function which links students, staff and employer
partners to initiatives outside the curriculum. The work and projects
which characterised the first six months of operation are described. The
authors reflect on the themes and issues to emerge from the first
National Student Enterprise Network Conference, hosted by Chester
College in January 1991. There is considerable potential for realising
EHE goals through more effective structuring and networking between
students in different institutions.
Integrating Learning and Working
Authors: Coulson‐Thomas Colin J.
Published: May 2006

Reports the key findings of a survey of major companies which
reveal a diversity of individual and corporate learning requirements
which are difficult to address through public programmes. As companies
build differentiated corporate cultures they are finding it more
difficult to absorb “general inputs” or “standard
solutions” from outside. There are however opportunities for
external partners to work with them in the identification and definition
of workplace based projects that would be both intrinsically important
and offer development opportunities.
Bridging the Academic‐vocational Divide: Curriculum Developments for the Over‐16s
Authors: Nicholls Anne
Published: May 2006

Discusses schemes for new qualifications combining academic and
vocational areas of the 16‐to 19‐years age group: the Technological
Baccalaureate and the Diploma of Vocational Education. Emphasizes the
role City and Guilds is playing in the development of both.