bluuebunny/crossref_metadata_2025 huggingface dataset:
Food Hoarding by Merriam's Kangaroo Rats: A Test of Alternative Hypotheses
Authors: Jenkins Stephen H. , Rothstein Aron , Green Wendy C. H.
Published: May 2006

Merriam's kangaroo rats (Dipodomys merriami) store seeds in burrows (larderhoarding) and in small clumps in shallow holes dug in the soil (scatterhoarding). We used a large laboratory arena with an artificial burrow for larderhoarding and four sand—filled compartments for scatterhoarding to test several alternative hypotheses about spatial patterns of food caching. The hypotheses were that kangaroo rats prefer to (1) larderhoard seeds in burrows, (2) scatterhoard seeds near burrows, (3) scatterhoard seeds away from burrows, (4) scatterhoard seeds near food sources, or (5) make widely spaced scatterhoards. Three treatments that differed in the distance between the burrow and food source were used to discriminate among hypotheses (2) through (4). There was a substantial amount of variation among individuals in proportion of seeds that were larderhoarded. Subjects initially scatterhoarded seeds close to the food source, but distributed caches more evenly among caching compartments as trials progressed. Increased evenness of cache distribution resulted from harvesting and repositioning of extant caches as well as selective placement of new caches. Initial caching close to food may be adaptive by maximizing harvest rates during flushes of seed production and making seeds unavailable to non—digging competitors (birds and ants). Subsequent redistribution of caches may make them less available to other rodents that locate buried seeds by smell and use area—restricted search to find closely spaced scatterhoards.
Damage and Responsiveness of Jamaican Montane Tree Species after Disturbance by a Hurricane
Authors: Bellingham P. J. , Tanner E. V. J. , Healey J. R.
Published: May 2006

A severe hurricane affected Jamaican montane rain forests in 1988. We made local and widespread measurements of tree condition in three periods: prehurricane 1974–1984 (preh.); hurricane 1984—1989 (h.); and post—hurricane 1989—1992 (post—h.). In the h. period, 7.22% of stems and 4.72% of the total basal area died; crown loss was the most frequent cause of mortality. Among individual tree species, the hurricane caused a large range in mortality (0—26%) and non—fatal damage. Post—h. mortality was greater than mortality in the h. period, and varied among species. Post—h. stem growth rates (all species combined) were more than double the prehurricane rates, but species showed a considerable range from no significant increase to eight times greater. We classified 20 common tree species using damage scores (normalized h. mortality, plus normalized change in mortality from preh. to post—h., plus normalized complete crown loss in h.) and response scores (normalized change, preh. to post—h., in recruitment to the ≥ 3 cm dbh size class, plus normalized change in growth rate from preh. to post—h., plus normalized frequency of sprouts). Species were assigned to one of four groups: resistant (11 species), with low damage and low response; susceptible (5 species), with high damage and low response; resilient (1 species), with high damage and high response; and usurpers (3 species), with low damage and high responsiveness. The grouping of species was broadly related to their regeneration requirements. Most species with seedlings usually found under closed canopy were resistant; three of the four species with seedlings usually found on landslides were also resistant. Species with seedlings most frequently found in gaps included resilient, susceptible, and usurper species, but were not usually resistant. It is likely that the three species classified as usurpers will increase their relative abundance in the forest in the next decades and that Cyathea pubescens, which was very susceptible, will decrease in relative abundance of adults. Most of the other species are likely to have small changes in their relative abundances. Thus, at present, hurricanes have few long—term effects on the forests, although a change in the disturbance regime may alter this.
Demographic Models for Leptogorgia Virgulata, A Shallow‐Water Gorgonian
Authors: Gotelli Nicholas J.
Published: May 2006

I used time—invariant and time—varying matrix models to analyze the demography of Leptogorgia virgulata, a shallow—water gorgonian. For a local population in the northeastern Gulf of Mexico, I estimated monthly rates of recruitment, colony growth, and mortality in a mapped 24—m2 plot for 2 yr. In a time—invariant model, average mortality and recruitment rates were nearly balanced, so the population growth rate, ln (@l), was close to 0.0. An elasticity analysis showed recruitment contributed <5% to the measured rate of population growth. The most important component of population growth rate was survivorship, particularly of the large size classes. Results were similar for a patch model that incorporated spatial variation in recruitment and colony growth rates. Several published transition matrices of forest trees, which have a similar life history, were also characterized by low elasticities for recruitment. Fluctuations in population size of L. virgulata were analyzed with a time—varying matrix model. I randomized certain elements in the 23 monthly projection matrices and simulated the population track. For models with random temporal variation in survivorship, standard deviations (and coefficients of variation) of population size were consistently larger than observed. This result suggests that temporal variation in mortality rates tended to damp population fluctuations. The damping occurred at low population sizes: models with random variation in survivorship generated significantly smaller minimum population sizes than observed. In contrast, population tracks with random temporal variation in recruitment were not consistently different from observed. Although recruitment is widely regarded as an important factor structuring marine communities, its contribution to the temporal (but not spatial) dynamics of L. virgulata was minimal. This finding may be typical of long—lived organisms with delayed reproduction and indeterminate growth, such as forest trees and many sessile marine invertebrates.
Holocene Vegetation Patterns in the Adirondack Mountains
Authors: Jackson Stephen T. , Whitehead Donald R.
Published: May 2006

Pollen and plant macrofossil date from six sites along an elevational gradient (661—1320 m) in the east—central Adirondack Mountains (New York) reveal the history of six tree taxa (Picea, Abies, Pinus strobus, Tsuga, Betula papyrifera,B. lutea) in the region during the past 10 000 yr. Space—time plots of the data show how spatial patterns of vegetation along the elevational gradient changed during the Holocene in response to climatic, biotic, and other changes. The plots also illustrate the contrasting spatial scales at which pollen and plant macrofossil data sense forest composition. Vegetational patterns along the gradient changed substantially during the Holocene. Responses of the six tree taxa to temporal changes in environment were individualistic, resulting in continual changes in the spatial vegetation patterns. The modern elevational zonation developed only within the past 3000 yr. Each tree taxon has a unique abundance pattern along the spatial and temporal gradients. Pollen percentages of Picea, Pinus, Tsuga, and Betula did not vary systematically with elevation, but changed substantially with time, indicating changes in abundance of these taxa at a regional scale. Macrofossil percentages of all six taxa varied with both time and elevation, revealing temporal changes in abundance of these taxa along the elevational gradient. Abies populations were concentrated at a higher elevations, while Pinus strobus, Tsuga, and Betula lutea trees were most abundant at lower elevations. The elevational distributions and low—elevation abundance of the latter three taxa changed substantially during the Holocene. Picea trees were rare at all elevations during the early and mid—Holocene, and increased in abundance at mid—elevation sites within the past 3000 yr.
Low back pain and musculoskeletal symptoms among Kansas farmers
Authors: Rosecrance John , Rodgers Gina , Merlino Linda
Published: May 2006

Background

Farming continues to rank as one of the most dangerous occupations in the United States. The purpose of this study was to determine the prevalence of low back pain and other musculoskeletal disorders (MSDs) among the farmers and to examine the factors associated with occupational back pain. Farmers in a predominately corn and soybean growing region of Kansas served as the study sample.

Methods

Questionnaires were mailed out to 499 active farmers of a Farmers' Cooperative in Southeast Kansas. The self‐administered questionnaire was used to determine the prevalence of self‐reported symptoms of back pain and other MSDs and to determine the strength of associations between back pain and work factors.

Results

The participation rate was 57.2%. The low back was the anatomical area with the highest prevalence of self‐reported work‐related pain (37.5%), followed by the shoulders (25.9%), knees (23.6%), and neck (22.4%). Close to 60% of the farmers reported that they experienced farm work‐related MSD symptoms in at least one of the nine body areas in the previous year. Nearly one quarter of the farmers reported seeing a physician for their low back symptoms, and one in five farmers had to modify their work habits due to low back symptoms during the previous year.

Conclusions

Low back pain and other musculoskeletal conditions are a significant problem for Kansas farmers. This group of Kansas farmers experienced low back pain at a much higher rate than the general working population and higher than other groups of farmers previously studied. Am. J. Ind. Med. 49:547–556, 2006. © 2006 Wiley‐Liss, Inc.
ImmunoTrack®: The novel antibody‐based technology for tracing in animal health
Authors: Ruehland Claus , Reichel Christoph , Neugebauer Markus , Strich Sandra , Bertling Wolf M. , Reiser Christian O. A. , Hess Juergen
Published: May 2006

This paper describes a novel antibody‐based livestock movement control tool and method of meat allocation, both in livestock husbandry as well as during the meat‐processing chain. Immuno Track® fulfills diverse prerequisites and meets regulatory demands which are substantial for a successful monitoring technology: (i) the induction of long‐lasting antibody responses detectable onsite throughout the whole mast period of pigs, (ii) a single immunization injection with protein derivatives is sufficient to evoke a strong epitope‐specific antibody response, and (iii) the complete degradation of the protein markers after the antibody response has been triggered in meatproducing animals such as cattle or pigs. There are diverse fields of application for the Immuno‐Track marker technology, such as in quality meat programs, as compliance markers for animal vaccines or as a tool for verification of origin. Combination of this monitoring technology with the husbandry and identification databases for cattle and pigs within the European Community will lead to greater transparency in meat production, thereby regaining consumers' trust in concomitant structures of the meat‐producing industry.
Computational design of proteins stereochemically optimized in size, stability, and folding speed
Authors: Joshi Sadhna , Rana Soumendra , Wangikar Pramod , Durani Susheel
Published: May 2006

Artificial proteins potentially barrier‐free in the folding kinetics are approached computationally under the guidance of protein‐folding theories. The smallest and fastest folding globular protein triple‐helix‐bundle (THB) is so modified as to minimize or eliminate its presumed barriers in folding speed. As the barriers may reside in the ordering of either secondary or tertiary structure, the elements of both secondary and tertiary structure in the protein are targeted for prenucleation with suitable stereochemically constrained amino acid residues. The required elements of topology and sequence for the THB are optimized independently; first the topology is optimized with simulated annealing in polypeptides of highly simplified alphabet; next, the sequence in side chains is optimized using the standard inverse design methods. The resultant three best‐adapted THBs, variable in topology and distinctive in sequences, are assessed by comparing them with a few benchmark proteins. The results of mainly molecular dynamics (MD) comparisons, undertaken in explicit water at different temperatures, show that the designed sequences are favorably placed against the chosen benchmarks as THB proteins potentially thermostable in the native folds. Folding simulation experiments with MD establish that the designed sequences are rapid in the folding of individual helices, but not in the evolution of tertiary structure; energetic cum topological frustrations remain but could be the artifacts of the starting conformations that were chosen in the THBs in the folding simulations. Overall, a practical high‐throughput approach for de novo protein design has been developed that may have fruitful application for any type of tertiary structure. © 2006 Wiley Periodicals, Inc. Biopolymers 83: 122–134, 2006

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Photoelectrochemical Kinetics of Eosin Y‐Sensitized Zinc Oxide Films Investigated by Scanning Electrochemical Microscopy
Authors: Shen Yan , Nonomura Kazuteru , Schlettwein Derck , Zhao Chuan , Wittstock Gunther
Published: May 2006

Eosin Y is used as a sensitizer for nanoporous zinc oxide films for prospective applications in photoelectrochemical solar cells. The kinetics of the reduction of the intermittently formed photo‐oxidized dye molecules by iodide ions in the electrolyte phase was investigated by using the feedback mode of scanning electrochemical microscopy (SECM). The bulk solution phase contained triiodide as electron transfer mediator, from which the ultramicroelectrode‐generated iodide ions acted as electron donors for photo‐oxidized Eosin Y molecules (D+ads) at the zinc oxide sample. Effective rate constants for the dye regeneration could be extracted from the SECM approach curves. The effective rate constants at different triiodide concentrations could be related to the rate constant for the reaction of the dissolved donor with photo‐oxidized Eosin Y bound to ZnO, as well as to the overall rate of the photosensitization process. For the reaction D+ads + 1.5 I−→Dads + 0.5 I3− a rate constant of kox = (1.4±0.8)×108 cm9/2 mol−3/2 s−1 was determined.
Competing Magnetic Interactions in Na10Co4O10, Studied by Neutron Diffraction
Authors: Stüßer Norbert , Sofin Mikhail , Bircher Roland , Güdel Hans‐Ulrich , Jansen Martin
Published: May 2006

Na10Co4O10 was investigated by neutron powder diffraction at 230, 70, and 4 K. The crystal structure, determined previously by X‐ray diffraction on single crystals, was confirmed. Na10Co4O10 orders magnetically below 37 K. All observed magnetic reflections could be indexed by integers (hkl) with respect to the chemical unit cell and the magnetic propagation vector q=0. The refinement was performed in the Shubnikov space group C2/c and indicated a collinear antiferromagnetic spin structure. The determined spin arrangement is consistent with the magnetic intratetramer interactions suggested previously from the analysis of magnetic susceptibility data: the magnetic moments of the central CoIII ions of the Co4O10 tetramer lie parallel to each other and couple in an antiparallel fashion to the terminal CoII moments. The Rietveld analysis shows that the net moments of 0.64 μB per tetramer form ferromagnetic layers parallel to the ab plane. Adjacent layers are coupled antiferromagnetically along c. The spins are aligned in the ac plane along the line connecting adjacent CoII and CoIII ions of the tetramer. We have determined unusually low values for the ordered magnetic moments of 2.43(5) μB and 2.11(6) μB for CoIII and CoII, respectively. The occurrence of spontaneous magnetization below 37 K indicates a slight canting of 2.2° of the antiferromagnetic structure. A representation analysis shows that a weak ferromagnetic component along b is compatible with the determined antiferromagnetic structure.
Synthesis of Doubly Strappedmeso–meso‐Linked Porphyrin Arrays and Triply Linked Conjugated Porphyrin Tapes
Authors: Ikeda Toshiaki , Lintuluoto Juha M. , Aratani Naoki , Yoon Zin Seok , Kim Dongho , Osuka Atsuhiro
Published: May 2006

1,10‐Dioxydecamethylene doubly strapped ZnII‐porphyrinS1was prepared and treated with AgPF6to givemeso–meso‐linked porphyrin oligomersSn(n= 2, 3, 4, 6, 8, and 12), which were converted to triply linked porphyrin tapesTSnbymeso,meso′‐dibromomeso–meso‐linked porphyrin arraysBSnandmeso,meso′‐diphenylmeso–meso‐linked porphyrin arraysPSn. The structures ofS1andS2have been determined by single‐crystal X‐ray diffraction analysis. Characteristically,Snexhibit sharp Q(0,0) absorption and fluorescence bands. Low energy Q‐band‐like absorption bands ofTSnare progressively red‐shifted with an increase in the number of porphyrins without saturation behavior of conjugation. The double straps suppress π–π stacking to some extent as seen from partial preservation of vibration structures in the Q‐band‐like bands ofTS4andTS6and improve the chemical stabilities of longer tapes such asTS8andTS12. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Syntheses, characterizations, and crystal structures of tri‐ and diorganotin (IV) derivatives with 2‐mercapto‐5‐methyl‐1,3,4‐thiadiazole
Authors: Ma Chunlin , Li Jikun , Zhang Rufen
Published: May 2006

A series of organotin(IV) complexes with 2‐mercapto‐5‐methyl‐1,3,4‐thiadiazole (HL) of the type R3 Sn(L) (R = Me 1; Bu 2; Ph 3; PhCH2 4) and R2Sn(L)2 (R = CH3 5; Ph 6; PhCH2 7; Bu 8) have been synthesized. All complexes 1–8 were characterized by elemental analysis, IR,1H, 13 C, and 119Sn NMR spectra. Among these, complexes 1, 3, 4, and 7 were also determined by X‐ray crystallography. The tin atoms of complexes 1, 3, and 4 are all penta‐coordinated and the geometries at tin atoms of complexes 3 and 4 are distorted trigonal–bipyramidal. Interestingly, complex 1 has formed a 1D polymeric chain through Sn and N intermolecular interactions. The tin atom of complex 7 is hexa‐coordinated and its geometry is distorted octahedral. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:353–364, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20215
Syntheses and spectroscopic investigation of some cyclophosphazanes: Analysis of pseudo‐triplet splitting
Authors: Gholivand Khodayar , Shariatinia Zahra , Tabasi Zahra Ahmadian , Tadjarodi Azadeh
Published: May 2006

Some new phosphoramidates, 1–3, and the corresponding cyclophosphazanes, 4–6, with formula Cl2P(p‐NHC6H4CH3) 1, Cl2P(O)(p‐NHC6H4NO2) 2, (CH3)2NP(O)Cl(p‐NHC6H4CH3)3, [ClP(p‐NC6H4CH3)]2 4, [ClP(O)(p‐NC6H4NO2)]2 5, and [(CH3)2NP(O)(p‐NC6H4CH3)]2 6 were synthesized and characterized by 1H, 13C, 31P NMR, IR, mass spectroscopy, and elemental analysis. A pseudo‐triplet signal was observed in the 1H NMR spectrum of molecule 6 for the N(CH3)2 protons. The A6A′ 6X2 spin system was suggested for the pseudo‐triplet pattern of 3JPNCH coupling in this molecule. Ab initio calculations were performed at the HF and B3LYP levels of theory with 6‐311G** standard basis set on the geometry of compound 6. Also, the NMR chemical shift calculations were done to compare the computed results with the experimental ones. The calculated results are in good agreement with experimental data. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:337–343, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20229
Electrochemical behavior of aluminium in acidic media
Authors: Jain T. , Chowdhary R. , Mathur S.P.
Published: May 2006

The inhibitive action of the acid extracts of seeds' leaves and bark from the Ficus virens plant towards hydrochloric and sulfuric acid corrosion of aluminium is tested using mass loss and thermometric techniques. It was found that the extract acts as a good corrosion inhibitor for aluminium corrosion in all concentration of hydrochloric and sulfuric acid solution. The ellagic acid has been used as a representative of the tannin species. The tannins are anodic inhibitors. The inhibition efficiency (IE) increases as the extract concentration is increased. The effect of temperature on the IE was studied. It was found that the presence of extract increases the activation energy of the corrosion reaction. Moreover, the heat of adsorption (Qads) was also calculated. It was found that the Ficus virens extract provides a good protection against pitting corrosion in chloride ion containing solution.
Active catheter tracking using parallel MRI and real‐time image reconstruction
Authors: Bock Michael , Müller Sven , Zuehlsdorff Sven , Speier Peter , Fink Christian , Hallscheidt Peter , Umathum Reiner , Semmler Wolfhard
Published: May 2006

In this work active MR catheter tracking with automatic slice alignment was combined with an autocalibrated parallel imaging technique. Using an optimized generalized autocalibrating partially parallel acquisitions (GRAPPA) algorithm with an acceleration factor of 2, we were able to reduce the acquisition time per image by 34%. To accelerate real‐time GRAPPA image reconstruction, the coil sensitivities were updated only after slice reorientation. For a 2D trueFISP acquisition (160 × 256 matrix, 80% phase matrix, half Fourier acquisition, TR = 3.7 ms, GRAPPA factor = 2) real‐time image reconstruction was achieved with up to six imaging coils. In a single animal experiment the method was used to steer a catheter from the vena cava through the beating heart into the pulmonary vasculature at an image update rate of about five images per second. Under all slice orientations, parallel image reconstruction was accomplished with only minor image artifacts, and the increased temporal resolution provided a sharp delineation of intracardial structures, such as the papillary muscle. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Krylov precise time‐step integration method
Authors: Fung T. C. , Chen Z. L.
Published: May 2006

An efficient precise time‐step integration (PTI) algorithm to solve large‐scale transient problems is presented in this paper. The Krylov subspace method and the Padé approximations are applied to modify the original PTI algorithm in order to improve the computational efficiency. Both the stability and accuracy characteristics of the resultant algorithms are investigated. The efficiency can be further improved by expanding the dimension to avoid the computation of the particular solutions. The present algorithm can also be extended to tackle nonlinear problems without difficulty. Two numerical examples are given to illustrate the highly accurate and efficient algorithm. Copyright © 2006 John Wiley & Sons, Ltd.
Promoting autonomy of the client with persistent mental illness: A challenge for occupational therapists from The Netherlands, Germany and Belgium
Authors: Le Granse Mieke , Kinébanian Astrid , Josephsson Staffan
Published: May 2006

The aim of this study was to determine how occupational therapists from The Netherlands, Germany and Belgium promote the autonomy of clients with persistent mental illness. Sixty occupational therapists working in psychosocial mental health completed two semi‐structured questionnaires. Data were analysed by applying the constant comparative method. The results of the study show the importance of handling motivation in relation to personal autonomy and the different strategies occupational therapists use in promoting autonomy. In conclusion, enhancing clients' personal autonomy will empower and help them to discover meaningful occupations. More in‐depth information could have been obtained using an interview in combination with observations. Further research is needed to evaluate the effectiveness of strategies used by occupational therapists in promoting clients' autonomy. Copyright © 2006 John Wiley & Sons, Ltd.
Hyperbranched polycarbosiloxane with dendritic boron cores: Synthesis, characterization, and structure regulation
Authors: Kong Jie , Fan Xiaodong , Si Qingfa , Zhang Guobin , Wang Shengjie , Wang Xin
Published: May 2006

The synthesis, characterization, and structure regulation of hyperbranched polycarbosiloxane with dendritic boron cores were realized in this paper. First, dendritic boron core was synthesized via hydroboration with borane dimethylsulfide and bis(allyloxy)dimethylsilane. Then, the hyperbranched polycarbosiloxanes with dendritic boron cores were synthesized via hydrosilylation with AB2type monomer of bis(allyloxy)methylsilane and dendritic boron cores. The molecular structures of the dendritic boron core and resulting hyperbranched polymers were characterized by using Fourier transform infrared spectroscopy,1H nuclear magnetic resonance, and13C nuclear magnetic resonance spectroscopies. Size exclusion chromatography/multiangle laser light scattering analysis reveals that the structures of hyperbranched polycarbosiloxane can be regulated effectively by incorporation of functional dendritic boron cores. Compared with hyperbranched polycarbosiloxane of the same molecular weight level, the hyperbranched polycarbosiloxane with dendritic boron cores presents narrower molecular weight distribution as well as much smaller hydrodynamic radius and intrinsic viscosity. Thermalgravimetric analyzer analysis indicates that both the decomposition temperature and ceramic yields are increased as the results of the incorporation of dendritic boron cores into hyperbranched polycarbosiloxane. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3930–3941, 2006
Aligned single‐wall carbon nanotube polymer composites using an electric field
Authors: Park Cheol , Wilkinson John , Banda Sumanth , Ounaies Zoubeida , Wise Kristopher E. , Sauti Godfrey , Lillehei Peter T. , Harrison Joycelyn S.
Published: May 2006

While high shear alignment has been shown to improve the mechanical properties of single‐wall carbon nanotube (SWNT)‐polymer composites, this method does not allow for control over the electrical and dielectric properties of the composite and often results in degradation of these properties. Here, we report a novel method to actively align SWNTs in a polymer matrix, which permits control over the degree of alignment of the SWNTs without the side effects of shear alignment. In this process, SWNTs were aligned via AC field‐induced dipolar interactions among the nanotubes in a liquid matrix followed by immobilization by photopolymerization under continued application of the electric field. Alignment of SWNTs was controlled as a function of magnitude, frequency, and application time of the applied electric field. The degree of SWNT alignment was assessed using optical microscopy and polarized Raman spectroscopy, and the morphology of the aligned nanocomposites was investigated by high‐resolution scanning electron microscopy. The structure of the field induced aligned SWNTs was intrinsically different from that of shear aligned SWNTs. In the present work, SWNTs are not only aligned along the field, but also migrate laterally to form thick, aligned SWNT percolative columns between the electrodes. The actively aligned SWNTs amplify the electrical and dielectric properties of the composite. All of these properties of the aligned nanocomposites exhibited anisotropic characteristics, which were controllable by tuning the applied field parameters. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1751–1762, 2006
Effect of annealing time on the self‐nucleation behavior of semicrystalline polymers
Authors: Lorenzo Arnaldo T. , Arnal María L. , Sánchez Johan J. , Müller Alejandro J.
Published: May 2006

It is widely known that when a polymer is heated just above its melting point and is kept at a given temperature (denoted Ts) for a short time, when it is cooled down its nucleation density increases and its peak crystallization temperature shifts to higher temperatures, as detected for instance by differential scanning calorimetry (DSC). The Ts temperature range where the described process occurs has been named Domain II self‐nucleation (SN) because the selected Ts temperatures are high enough to melt the polymer without causing detectable annealing of any remnant crystals by DSC. Experimental results obtained by DSC, polarized light optical microscopy (PLOM), and rheology indicate that these techniques are unable to detect any remaining crystal fragments in Domain II. Our kinetic results demonstrate that Domain II SN is a transient phenomenon that can even disappear if enough time at Ts is allowed. Results of the study of the time dependence of the SN effect indicates two possibilities: (a) if crystal fragments are present (even if undetected by the employed techniques) their final melting is a very slow process (in the order of hours); (b) if all crystallites have melted in Domain II, then it may be more plausible to reinterpret self‐nuclei as arising from “precursors” whose detail nature has not been the subject of this investigation but that can be regarded as either a residual segmental orientation in the melt (i.e., a melt memory effect) or a mesophase in a preordered state. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1738–1750, 2006
Si diffusion in epitaxial GaN
Authors: Jakiela Rafal , Barcz Adam , Dumiszewska Ewa , Jagoda Andrzej
Published: May 2006

The aim of this work is to determine diffusion coefficient of silicon in gallium nitride under different annealing conditions. Silicon was implanted into 3 µm thick GaN layer deposited on sapphire substrate with MOVPE (Metalorganic Vapour Phase Epitaxy) method. Implantation was performed at room temperature to a dose of 6×1015/cm2 at energy of 100 keV. The samples were annealed under 1 atm nitrogen pressure at 900–1200 °C with or without an AlN protective layer. The extent of diffusion of the implanted species was characterized using the SIMS (Secondary Ion Mass Spectrometry) technique. The resultant concentration profiles are characterized with two diffusion fronts: slow diffused Si atoms at high concentration and fast diffused Si atoms at low concentration. We ascribe the first mechanism as to originate from diffusion in the crystal bulk (substitutional migration), while the second one – from diffusion via grain boundaries/dislocations. Si diffusion coefficient in a crystal was found to be dependent on annealing conditions, in contrast to diffusion via grain boundary. Calculated diffusion coefficient parameters for annealing with and without AlN layer amount respectively to: DO = 6.5×10–11 cm2/s, Ea = 0.89 eV and DO = 9.1×10–8 cm2/s, Ea = 1.55 eV. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Twin concordances test for ascertained trichotomous traits data
Authors: Huang Jason Kunming , Tai John Jen
Published: May 2006

In human genetics, twin studies are widely underwent for investigation of the genetic influence on diseases. There are several measures that had been proposed to evaluate the similarity between two twins for dichotomous traits when the twins are sampled at random. These measures include the correlations, odds ratios, and casewise and pairwise concordances. When data are sampled through an ascertainment procedure, truncated data are formed. Under this circumstance, odds ratio cannot be defined and correlations cannot be correctly estimated. However, concordance measures for dichotomous traits can still be estimated using the likelihood method. On the other hand, though theoretically concordance measures can be extended to trichotomous traits, how to define them and to derive their estimators for ascertained trichotomous traits data have not been thoroughly discussed. In this study, we aim to address several relevant issues for ascertained trichotomous traits data. We define two new (casewise and pairwise) concordance measures for trichotomous traits and demonstrate how to apply a so‐called ‘self‐contained subsets method (SCSM)’ to estimation of twin concordances for ascertained data. We show that this method can obtain the same estimates as the likelihood method in an easier way and derive the asymptotic variances of the SCSM estimates under ascertainment. We establish the testing procedure for test of the equality of concordance measures between monozygotic twin pairs and dizygotic twin pairs, and illustrate the methods with a real data set and conduct Monte Carlo simulation to investigate its power performance. Copyright © 2006 John Wiley & Sons, Ltd.
Anaemia is an independent predictor of mortality in patients with left ventricular systolic dysfunction following acute myocardial infarction☆
Authors: Valeur Nana , Nielsen Olav Wendelboe , McMurray John J.V. , Torp‐Pedersen Christian , Køber Lars ,   TRACE Study Group
Published: May 2006

Background

In patients with chronic heart failure (HF), mortality is inversely related to haemoglobin (hgb) concentration. We investigated the prognostic importance of anaemia in patients with acute myocardial infarction (AMI) and left ventricular systolic dysfunction (LVSD) with and without HF.

Methods and results

We studied 1731 patients with AMI and left ventricular ejection fraction ≤35% from the TRAndolapril Cardiac Evaluation (TRACE) study. Mild anaemia (110 g/L ≤ hgb < 120 g/L in women and 120 g/L ≤ hgb < 130g/L in men) was present in 264 patients (15%), 114 (7%) had moderate (100 g/L ≤ hgb < 110 g/L in women and 110 g/L ≤ hgb < 120g/L in men) and 59 (3%) had severe (hgb < 100 g/L in women and < 110g/L in men) anaemia. According to the WHO criteria (hgb ≤120g/L in women and < 130g/L in men), 25% had anaemia. Anaemia was associated with increasing age, higher serum creatinine, lower body mass index, history of chronic HF, and worse NYHA class. In multivariable analyses including other prognostic factors only severe anaemia was associated with increased mortality, hazard ratio 1.59 (1.20–2.11). Anaemia was of prognostic importance in patients with HF, but not without HF. In HF patients the hazard ratios were 1.73 (1.26–2.36), 1.20 (0.93–1.56) and 1.05 (0.88–1.25) for severe, moderate and mild anaemia, respectively.

Conclusion

Anaemia is an independent predictor of mortality in patients with AMI and LVSD, but prognostic importance of anaemia is confined to the first year following AMI. The increased risk is driven by patients with severe anaemia and HF.
The transition metal chelator nicotianamine is synthesized by filamentous fungi
Authors: Trampczynska Aleksandra , Böttcher Christoph , Clemens Stephan
Published: May 2006

Nicotianamine is an important metal ligand in plants. Surprisingly, recent genome sequencing revealed that ascomycetes encode proteins with similarity to plant nicotianamine synthases (NAS). By expression in a Zn2+‐hypersensitive fission yeast mutant we show for a protein from Neurospora crassa that it indeed possesses NAS activity. Using electrospray‐ionization‐quadrupole‐time‐of‐flight mass spectrometry we prove the formation of nicotianamine in N. crassa. Transcript level is strongly upregulated under Zn deficiency as shown by real‐time PCR. These findings demonstrate that nicotianamine is more widespread in nature than anticipated and provide further evidence for a function of nicotianamine as a cytosolic chelator of Zn2+ ions.
Serum from pemphigus vulgaris reduces desmoglein 3 half‐life and perturbs its de novo assembly to desmosomal sites in cultured keratinocytes
Authors: Cirillo Nicola , Femiano Felice , Gombos Fernando , Lanza Alessandro
Published: May 2006

Defects of cell–cell adhesion underlie disruption of epithelial integrity observed in patients with pemphigus vulgaris (PV), an autoimmune disease characterized by severe mucosal erosions and skin blisters. Pathogenic PV autoantibodies found in patients’ sera target desmoglein 3 (Dsg3), a major component of the desmosome, but how does this phenomenon affect Dsg‐dependent adhesion and lead to acantholysis still remains controversial. Here, we show that PV serum determines a reduction of Dsg3 half‐life in HaCaT keratinocytes, although the total amount of Dsg3 remains unchanged. Immunofluorescence studies suggest that PV IgG exert their effect prevalently by binding non‐desmosomal Dsg3 without causing its massive internalization. Furthermore, PV IgG targeting desmosome‐assembled Dsg3 do not induce depletion of Dsg3 from the adhesion sites. Conversely, incorporation of PV IgG‐Dsg3 complexes into new forming desmosomes appears perturbed. With our study, the basic biochemical changes of Dsg3 in an in vitro model of PV have been defined.
The genetic structure of Pandalus borealis in the Northeast Atlantic determined by RAPD analysis
Authors: Martinez Iciar , Aschan Michaela , Skjerdal Taran , Aljanabi Salah M.
Published: May 2006

The genetic structure of shrimp (Pandalus borealis) in the Northeast Atlantic was examined by RAPD analysis on specimens caught at eight stations in the Barents Sea, three off Svalbard, two off Jan Mayen, and in two northern Norwegian fjords (19 < n > 31 per station). A total of 34 polymorphic markers generated by seven 10-mer arbitrary primers was used to assess the genetic population structure using analysis of molecular variance (AMOVA). There was considerable RAPD diversity (>90%) among shrimp at all stations. The two Norwegian fjords and the Jan Mayen stations were different from all the others, and the Jan Mayen stations also differed from each other. More than 98% of the genetic variation between Barents Sea and Svalbard was ascribed to individual diversity, and there was no significant difference between the two areas, although there seemed to be a subpopulation structure in the Barents Sea. Principal component analysis on the frequency of each RAPD marker on each sampled station confirmed the presence of three populations: Barents Sea and Svalbard, northern Norwegian fjords, and Jan Mayen. We postulate that the large genetic variability found at an individual level may provide the total population with a diverse genetic pool from which traits can be selected to respond to variations in local environmental conditions, and that this local selection may be the cause of the subpopulation structure observed.
Protestant vibrations? Reggae, Rastafari, and conscious Evangelicals
Authors: ROMMEN TIMOTHY
Published: May 2006

The globalisation of reggae continues to engender a wide range of highly poignant re-inscriptions and re-interpretations of reggae's sound and of Rastafarian thought. One of the most compelling of these has been the negotiation of Rastafarian and Christian ideologies within the context of Protestant reggae bands and artists. The application of Rastafarian thought, dress and language to the evangelical concerns of Protestants – at times paradoxical, at others ingenious – signals an important moment of inter-religious contact that opens a window onto the complexities and multiple meanings that attach to music and to religious systems as they travel between the local and the global. This essay considers music by Christafari (United States), Sherwin Gardner (Trinidad and Tobago), and Stitchie (Jamaica), and considers questions related to the parallel globalisation of reggae and Rastafari. It does this by interrogating the extent to which authenticity, positionality, and religious context inform the use of and interpretation of Rastafari symbols within gospel reggae. In so doing, I introduce a concept that I call the negotiation of proximity, and offer some reflections on the ways that the Rastafari elements within gospel reggae might be understood in new, global (and newly localised) contexts.
‘Wrapped up’: ideological setting and figurative meaning in African-American gospel rap
Authors: VILJOEN MARTINA
Published: May 2006

In this article I shall attempt to demonstrate the application of an ideology-critical framework designed to give a comprehensive and differentiated account of textual ‘contradictions’ and ‘tensions’ in symbolic forms. Based on Johann Visagie's figurative semiotics of ideological discourse, this theoretical schema is demonstrated via an extensive analysis of the gospel rap video wrapped up by the African-American group Dawkins & Dawkins. As a metaphorically mediated enactment of contemporary-religious meaning, this instance of gospel rap is analysed as a forthright yet complex example of structural ambiguity. Allowing for a detailed reading of the semiotic layering surrounding and infiltrating all dimensions of this text, my interpretation problematises its reading as an uncomplicated, commercialised excursion into the pleasures of an embodied, danced religion. In both ‘highlighting’ and ‘hiding’ the layers of cultural meaning built into the metaphor of danced religion, wrapped up celebrates black religious identity without distancing it from underlying ideological formations associated with collective suffering and social injustice.
Gerard Kempers (1948–2005): a personal statement
Authors: Tagg Philip
Published: May 2006

I first met Gerard in 1975 in Örebro (Sweden) at the Nordic Piano Teachers' annual conference and workshops. Both of us were like fish out of water in discussions about the best fingering techniques to use in Beethoven sonatas. I had been asked to talk about popular music education and Gerard was on the lookout for fresh ideas for his art college in Lelystad. ‘I didn’t have a clue what you were actually saying' (in Swedish), he told me, ‘but it seemed to make sense’. What Gerard said he was trying to achieve in his college made perfect sense to me. He was determined to democratise music (and media) education: he wanted to right the wrong that consisted of excluding the music of the popular majority from officially sanctioned institutions of education and research. I had found a good friend and powerful ally. We kept contact from that time until very recently.
Alkenone‐based reconstruction of late‐Holocene surface temperature and salinity changes in Lake Qinghai, China
Authors: Liu Zhonghui , Henderson Andrew C. G. , Huang Yongsong
Published: May 2006

Few proxies can provide quantitative reconstructions of past continental climatic and hydrological changes. Here, we report the first alkenone‐based reconstruction of late Holocene temperature and salinity changes in Lake Qinghai, China. The alkenone‐temperature proxy (Uk′37) indicates up to a 1°C change in mean annual air temperature or a 2°C change in summer lake water temperature during the late Holocene. Oscillating warm and cold periods could be related to the 20th century warm period, the Little Ice Age, the Medieval Warm Period, the Dark Ages Cold Period, and the Roman Warm Period. The relative importance of C37:4 alkenone to total C37 alkenone production (%C37:4) fluctuated between 15–45%, with higher values during warm periods, suggesting that lake water was also fresher during these periods. The coupled late Holocene surface temperature and salinity changes suggest that Asian monsoons strongly influenced the climate of the Lake Qinghai region.
Impacts of the 2004 tsunami on groundwater resources in Sri Lanka
Authors: Illangasekare Tissa , Tyler Scott W. , Clement T. Prabhakar , Villholth Karen G. , Perera A. P. G. R. L. , Obeysekera Jayantha , Gunatilaka Ananda , Panabokke C. R. , Hyndman David W. , Cunningham Kevin J. , Kaluarachchi Jagath J. , Yeh William W.‐G. , van Genuchten Martinus T. , Jensen Karsten
Published: May 2006

The 26 December 2004 tsunami caused widespread destruction and contamination of coastal aquifers across southern Asia. Seawater filled domestic open dug wells and also entered the aquifers via direct infiltration during the first flooding waves and later as ponded seawater infiltrated through the permeable sands that are typical of coastal aquifers. In Sri Lanka alone, it is estimated that over 40,000 drinking water wells were either destroyed or contaminated. From February through September 2005, a team of United States, Sri Lankan, and Danish water resource scientists and engineers surveyed the coastal groundwater resources of Sri Lanka to develop an understanding of the impacts of the tsunami and to provide recommendations for the future of coastal water resources in south Asia. In the tsunami‐affected areas, seawater was found to have infiltrated and mixed with fresh groundwater lenses as indicated by the elevated groundwater salinity levels. Seawater infiltrated through the shallow vadose zone as well as entered aquifers directly through flooded open wells. Our preliminary transport analysis demonstrates that the intruded seawater has vertically mixed in the aquifers because of both forced and free convection. Widespread pumping of wells to remove seawater was effective in some areas, but overpumping has led to upconing of the saltwater interface and rising salinity. We estimate that groundwater recharge from several monsoon seasons will reduce salinity of many sandy Sri Lankan coastal aquifers. However, the continued sustainability of these small and fragile aquifers for potable water will be difficult because of the rapid growth of human activities that results in more intensive groundwater pumping and increased pollution. Long‐term sustainability of coastal aquifers is also impacted by the decrease in sand replenishment of the beaches due to sand mining and erosion.
Development of a new polarizable potential model of hydrogen fluoride and comparison with other effective models in liquid and supercritical states
Authors: Pártay Lívia , Jedlovszky Pál , Vallauri Renzo
Published: May 2006

Development of a new polarizable potential of hydrogen fluoride through the reparametrization of the JV-P model is presented: The length of the H–F bond has been shortened and the other parameters of the model have been readjusted accordingly. The structural, thermodynamic, and liquid-vapor equilibrium properties of the new model are compared with those of other effective potential models of HF as well as with experimental data in a broad range of thermodynamic states, from near-freezing to supercritical conditions. It is found that although the reparametrization does not change the structural properties of the HF model noticeably at the level of the pair correlations, it improves the reproduction of the thermodynamic properties of hydrogen fluoride over the entire range of existence of a thermodynamically stable liquid phase and also that of the vapor-liquid coexistence curve. However, the new model, which still overestimates the close-contact separation of the HF molecules, underestimates the density of the coexisting liquid phase and overestimates the saturation pressure, probably due to the too steep repulsion of the potential function.
Interfacial electronic structure of copper phthalocyanine and copper hexadecafluorophthalocyanine studied by photoemission
Authors: Lau K. M. , Tang J. X. , Sun H. Y. , Lee C. S. , Lee S. T. , Yan Donghang
Published: May 2006

Electronic structures of the heterojunction between copper phthalocyanine (CuPc) and copper hexadecafluorophthalocyanine (F16CuPc) were studied with ultraviolet photoemission spectroscopy. Band bending and an interface dipole were observed at the interface due to the formation of an electron accumulation layer and a depletion layer in F16CuPc and CuPc, respectively. Such an energy level alignment leads to interesting ambipolar characteristics for application of the CuPc∕F16CuPc junction in organic field-effect transistors.