bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evolution of taxonomic diversity gradients in the marine realm: a comparison of Late Jurassic and Recent bivalve faunas
Authors: Crame J. Alistair 
Published: July 2006

We still have much to learn about the evolution of taxonomic diversity gradients through geologic time. For example, have latitudinal gradients always been as steep as they are now, or is this a phenomenon linked to some form of Cenozoic global climatic differentiation? The fossil record offers potential to address this sort of problem, and this study reconstructs latitudinal diversity gradients for the last (Tithonian) stage of the Jurassic period using marine bivalves. At this time of relative global warmth, bivalves were cosmopolitan in their distribution and the commonest element within macrobenthic assemblages.Analysis of 31 regional bivalve faunas demonstrates that Tithonian latitudinal gradients were present in both hemispheres, though on a much smaller magnitude than today. The record of the Northern Hemisphere gradient is more complete and shows a steep fall in values at the tropical/temperate boundary; the Southern Hemisphere gradient exhibits a more regular decline in diversity with increasing latitude.Tithonian latitudinal gradients were underpinned by a tropical bivalve fauna that comprises almost equal numbers of epifaunal and infaunal taxa. The epifaunal component was dominated by three pteriomorph families, the Pectinidae, Limidae and Ostreidae, that may be regarded as a long-term component of tropical bivalve diversity. Of the mixture of older and newer “heteroconch” families that formed the bulk of the infaunal component, the latter radiated spectacularly through the Late Cretaceous and Cenozoic to dominate tropical bivalve faunas at the present day. This pulse of heteroconch diversification, which was a major cause of the steepening of the bivalve latitudinal gradient, provides important evidence that rates of speciation may be negatively correlated with latitude.Nevertheless, we cannot exclude the possibility that elevated extinction rates in the highest latitudes also contributed to the marked steepening of bivalve latitudinal gradients over the last 150 Myr. Rates of extinction within epifaunal bivalve taxa appear to have been higher in these regions through the Cretaceous period, but this was largely before any significant global climatic deterioration. Infaunal bivalve clades have had differential success over this time period in the polar regions. Whereas, in comparison with the Tropics, heteroconchs are very much reduced in numbers today, the anomalodesmatans are much better represented, and the protobranchs have positively thrived. We are beginning to appreciate that low temperature per se may not be a primary cause of elevated rates of extinction. Food supply may be an equally important control on both rates of speciation and extinction; those bivalves that have been able to adapt to the extreme seasonality of food supply have flourished in the polar regions.
Artificial time-averaging of marsh foraminiferal assemblages: linking the temporal scales of ecology and paleoecology
Authors: Martin Ronald E. , Hippensteel Scott P. , Nikitina Daria , Pizzuto James E. 
Published: July 2006

Multiple regression models were developed for seasonal test inputs to, and preservation of, marsh foraminiferal assemblages for a two-year period at Bombay Hook National Wildlife Refuge (BHNWR; Smyrna, Delaware). Seasonal assemblages were quite variable and yielded poor regression models. However, signal/noise ratios were amplified using artificially time-averaged (ATA) assemblages, in which separate dead and live abundances of the most abundant species were summed for all seasons. Regression models that used ATA species abundances to retrodict original sample depths accounted for up to ~99% (p < 0.0001) and ~91% (p < 0.023) of the variation of dead and live ATA assemblages, respectively, and usually retrodicted sample depths within 2–3 cm of actual depths.Artificially time-averaged assemblages were also used to extract multidecadal- to centennial-scale sea-level signals from near-surface assemblages at BHNWR formed during the past few centuries. The BHNWR sea-level curve closely resembles one previously published for marshes in Clinton, Connecticut (also based on foraminifera). The technique of artificial time-averaging therefore links the temporal scales of ecology and paleobiology by extracting high-resolution paleoenvironmental signals preserved in the fossil record.
Testing for bias in the evolution of coloniality: a demonstration in cyclostome bryozoans
Authors: McShea Daniel W. , Venit Edward P. 
Published: July 2006

Colonial organisms vary in the degree to which they are individuated at the colony level, i.e., in the degree to which the colony constitutes a unified whole, as opposed to a group of independent lower-level entities. Various arguments have been offered suggesting that evolutionary change along this continuum may be biased, that increases may be more probable than decreases. However, counterarguments can be devised, and the existing evidence is meager and inconclusive. In this paper, we demonstrate how the question can be addressed empirically by conducting a test for bias in a group of stenolaemate bryozoans, the cyclostomes. More specifically, we suggest three criteria for colony individuation: degree of connectedness among lower-level entities (in this case, zooids), degree of differentiation among lower-level entities, and number of intermediate-level parts. And we show how these criteria can be used together with a phylogeny and ancestral-state reconstruction methods to test for bias. In this case, results do not unambiguously support any single interpretation but are somewhat supportive of a null hypothesis of no bias in favor of increase.As part of the demonstration, we also show how results can be transformed into a quantitative estimate of an upper limit on bias. Finally, we place the question of bias in a larger context, arguing that the same criteria and methods we employ here can be used to test for bias in other colonial taxa, and also at other hierarchical levels, for example, in the transitions from free-living eukaryotic cells to multicellular organisms.
Inferring predation intensity in the marine fossil record
Authors: Leighton Lindsey R. 
Published: July 2006

Accurate estimates of predation intensity, the frequency of mortality from predation, are critical to studies of the evolution of species in response to predation, and to studies of predator-prey systems in general. Most commonly used indirect proxies for predation intensity in the fossil record have logistical or theoretical problems. Direct proxies, using actual traces of predatory activity, such as drilling and repair scars, may hold more promise. However, these direct proxies often have been used in conjunction with optimal foraging models, and in this context, the underlying assumptions and predictions of optimal foraging are examined.Results from theoretical models using optimal foraging suggest that (1) the ratio of internal shell volume to shell thickness of prey (benefit/cost ratio) may be a questionable measurement of prey “value” to the predator, as it fails to account adequately for energetic cost to the predator during pursuit and grappling; (2) drilling and repair frequency are invalid measures of prey preference, because optimal foraging predicts that specific prey types are either always taken or always ignored; (3) pooled drilling frequency will not be a useful metric of predation intensity in systems in which the predator need not always drill; and (4) an increase in repair frequency can be a consequence of either an increase or a decrease in predation intensity.Although drilling frequency may not indicate prey preference, it is a valid proxy for selection due to predation. An approach using size classes, in which the minimum size at which a predation refuge is achieved, is suggested for use with repair frequency.
Morphometric analysis of ontogeny and allometry of the Middle Ordovician trilobite Triarthrus becki
Authors: Kim Keonho , Sheets H. David , Haney Robert A. , Mitchell Charles E. 
Published: July 2006

Traditionally, the distinction between meraspis and holaspis among trilobites has been based on the achievement of the full adult complement of thoracic segments. Using a large sample (over 700 specimens collected from a single bed) we explore the utility of employing the ontogenetic trajectory of the cranidium as an alternative means to differentiate trilobite growth stages. This method is particularly useful for species represented solely by exuviae and disarticulated individuals. We use geometric morphometrics to examine shape change among cranidia ranging in size from 0.9 mm to 11.6 mm in cephalic length. The 114 measured specimens exhibit a rather continuous gradation in size in which no distinct instars are evident.The meraspid and holaspid specimens exhibit allometry when partial warp scores and uniform components of shape derived from thin-plate spline analysis are regressed onto log centroid size. To describe allometric shape change, deformation vectors from the smallest to the largest specimen in both ontogenetic stages are presented in three different superimposition settings by using a new software program. We have concluded that a new superimposition method (the Sliding Baseline Registration) is a useful tool for visualizing allometry in organisms that contain an axis of symmetry. As a result, we conclude that allometry is evident in meraspides and holaspides, but the degree of allometry in holaspides is very small relative to that in meraspides. The boundary between meraspis and holaspis in Triarthrus becki appears to correspond to a large change in the rate of ontogenetic change, but neither to a change in the direction of that trajectory nor to a cessation of ontogenetic change. This boundary also corresponds to a cranidium centroid size that matches well previous determinations that holaspis begins at about 2.8 mm in cephalic length.
Novel soluble aromatic poly(amideimide)s containing 9,9-diphenylfluorene moieties: characterization and optical properties
Authors: Schab-Balcerzak Ewa , Grabiec Eugenia , Jarząbek Bożena , Grobelny Łukasz , Kurcok Małgorzata , Mazurak Zbigniew 
Published: July 2006

Abstract
A series of aromatic poly(amideimide)s containing 9,9-diphenylfluorene moieties and the amide units in the main chain have been synthesized by solution polycondensation reaction of newly prepared diamidedianhydride with several aromatic diamines: 1,3-phenylenediamine, 3,3′-dimethoxy-biphenyl-4,4′-diamine, 4,4′-oxydianiline, 4,4′-(1,3-phenylenedioxy)dianiline, 4,4′-(9-fluorenylidene)dianiline and 1,5-diaminonaphthalene. Molecular structures of the polymers obtained have been characterized using 13C NMR, 1H NMR and FTIR spectroscopies. The polymers prepared are readily soluble in aprotic polar solvents, and form optically transparent films by solution casting. The resultant poly(amideimide)s have been analyzed by differential scanning calorimetry (DSC), thermogravimetry (TG) and wide-angle X-ray diffraction measurements. They exhibited high levels of thermal stability, with decomposition temperatures in the range 452–494 °C, and high glass transition temperatures (181–278 °C). The optical behavior of these polymers has been investigated in NMP solution as well as in the films. The photoluminescence (PL) spectra of the free-standing films prepared from the poly(amideimide)s exhibited maximum emission bands around 506–525 nm in the green region.
Consequences of error
Authors: Gordon Derek , Finch Stephen J. 
Published: July 2006

Abstract
Although misclassification errors are among the most ubiquitous elements of any gene mapping study, their consequences are often omitted or ignored. These errors, however, can cause deleterious results for the analysis of genetic data. Here we review the consequences of misclassification error in genetic linkage and association analysis. We also present recent methodological advances to estimate error rates and to incorporate errors into statistical tests of gene mapping. Computations for many of these advances may be performed through freely available software.
Posttranslational modifications to plants – glycosylation
Authors: Tekoah Yoram 
Published: July 2006

AbstractPosttranslational modifications (PTMs) of plants include glycosylation. As in mammals, plants attach both N‐ and O‐linked glycans, but the systems are not identical. More is known about the N‐linked type glycans. The complex N‐linked glycans of plants differ markedly in structure from those of animals. They more closely resemble those of insects and molluscs by not containing terminal sialic acids. The complex type glycans may contain an α‐(1,3)‐fucose (Fuc) linked to the proximal GlcNAc residue and/or a β‐(1,2)‐xylose (Xyl) residues attached to the α‐linked mannose (Man) of the glycan core, similar to what is found in insects and molluscs. These additional epitopes are thought to have antigenic and/or allergenic properties. Less is known about O‐linked glycans in plants. Recently, plants and algae have been utilized for the production of therapeutic proteins. Much more information on glycosylation of plants and algae and the ability to manipulate the glycosylation will have to be acquired, if these therapeutic proteins are to be effective.
Protein–ligand docking and structure‐based drug design
Authors: Oledzki Peter R. , Laurie Alasdair T. R. , Jackson Richard M. 
Published: July 2006

AbstractProtein‐ligand docking and de novo drug design have become increasingly important tools in aiding the drug design process, particularly with the recent increase in the number of pharmaceutically relevant macromolecular structures that have become available. Here, we review current methods and their applications, and highlight some recent successes in structure‐based drug design.
Colloidal Synthesis of Hollow Cobalt Sulfide Nanocrystals
Authors: Yin Y. , Erdonmez C. K. , Cabot A. , Hughes S. , Alivisatos A. P. 
Published: July 2006

AbstractFormation of cobalt sulfide hollow nanocrystals through a mechanism similar to the Kirkendall Effect has been investigated in detail. It is found that performing the reaction at > 120 °C leads to fast formation of a single void inside each shell, whereas at room temperature multiple voids are formed within each shell, which can be attributed to strongly temperature‐dependent diffusivities for vacancies. The void formation process is dominated by outward diffusion of cobalt cations; still, the occurrence of significant inward transport of sulfur anions can be inferred as the final voids are smaller in diameter than the original cobalt nanocrystals. Comparison of volume distributions for initial and final nanostructures indicates excess apparent volume in shells, implying significant porosity and/or a defective structure. Indirect evidence for fracture of shells during growth at lower temperatures was observed in shell‐size statistics and transmission electron microscopy images of as‐grown shells. An idealized model of the diffusional process imposes two minimal requirements on material parameters for shell growth to be obtainable within a specific synthetic system.
Inside Front Cover: Quantitative Measurement of the Local Surface Potential of π‐Conjugated Nanostructures: A Kelvin Probe Force Microscopy Study (Adv. Funct. Mater. 11/2006)
Authors: Liscio A. , Palermo V. , Gentilini D. , Nolde F. , Müllen K. , Samorì P. 
Published: July 2006

AbstractKelvin probe force microscopy provides quantitative insight into the electronic properties of thin molecular layers, as shown by the results of P. Samorì and co‐workers on p. 1407. In the cartoon shown in the inside front cover, a scanning charged tip probes the local surface potential of a self‐assembled layer, inducing charge polarization into a nanoscale “effective area”. These measurements make it possible to unravel the interplay between structural and electronic properties of molecule‐based materials and devices.We describe a systematic study on the influence of different experimental conditions on the Kelvin probe force microscopy (KPFM) quantitative determination of the local surface potential (SP) of organic semiconducting nanostructures of perylene‐bis‐dicarboximide (PDI) self‐assembled at surfaces. We focus on the effect of the amplitude, frequency, and phase of the oscillating voltage on the absolute surface potential value of a given PDI nanostructure at a surface. Moreover, we investigate the role played by the KPFM measuring mode employed and the tip–sample distance in the surface potential mapping by lift‐mode KPFM. We define the ideal general conditions to obtain a reproducible quantitative estimation of the SP and we find that by decreasing the tip–sample distance, the area of substrate contributing to the recorded SP in a given location of the surface becomes smaller. This leads to an improvement of the lateral resolution, although a more predominant effect of polarization is observed. Thus, quantitative SP measurements of these nanostructures become less reliable and the SP signal is more unstable. We have also devised a semi‐quantitative theoretical model to simulate the KPFM image by taking into account the interplay of the different work functions of tip and nanostructure as well as the nanostructure polarizability. The good agreement between the model and experimental results demonstrates that it is possible to simulate both the change in local SP at increasing tip–sample distances and the 2D potential images obtained on PDI/highly oriented pyrolytic graphite samples. These results are important as they make it possible to gain a quantitative determination of the local surface potential of π‐conjugated nanostructures; thus, they pave the way towards the optimization of the electronic properties of electroactive nanometer‐scale architectures for organic (nano)electronic applications.
Bubble dynamics during degassing of liquids at microgravity conditions
Authors: Divinis Nikolaos , Karapantsios Thodoris D. , de Bruijn Robert , Kostoglou Margaritis , Bontozoglou Vasilis , Legros Jean‐Claude 
Published: July 2006

AbstractThis work investigates the growth of bubbles generated in a liquid saturated with dissolved CO2 when its temperature is rapidly and locally raised above the saturation value, still below the boiling point of the test liquid. Three test liquids with different physical and transport properties were studied: water, glycerine/water mixture 42/58 w/w, and n‐heptane. Bubbles grow at the tip of a roughly spherical miniature heater (thermistor), whose temperature varies linearly with the power of an applied heat pulse. Nucleation and growth of single bubbles is studied, triggered either by continuous heat pulses or by intermittent heat pulses. A one‐dimensional spherically symmetric bubble growth model based on heat and mass transfer on the liquid side is employed to extract the average bubble temperature evolution curves from the experimental bubble growth curves. Comparisons between extracted average bubble temperature evolution data and measured thermistor temperatures reveal features of the heat‐triggered bubble growth. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Environmental technical and administrative innovations in the Canadian manufacturing industry
Authors: Henriques Irene , Sadorsky Perry 
Published: July 2006

AbstractThis paper explores whether the adoption of an EMS and/or TQM, both administrative innovations, lead to the development of cleaner technological innovations. We draw on the stakeholder influence literature and Daft's (1978) dual core model of organizational innovation to determine the factors affecting a facility's decision to undertake cleaner technological innovations. Using Canadian facility level manufacturing data, we find that an EMS reduces the likelihood that a facility will implement environmental technologies that change the production process (clean technologies) while TQM increases the likelihood that the facility will implement clean technologies. We also find that administrative pressures (corporate headquarters and shareholders/investors) have no impact on technological innovations while external stakeholders such as regulators, community groups and environmental groups as well as customers and suppliers each increase the likelihood that facilities will use cleaner technologies. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.
Types and influential factors of consumers' non‐purchasing ecological behaviors
Authors: Tilikidou Irene , Delistavrou Antonia 
Published: July 2006

AbstractThis article presents an examination of non‐purchasing ecological behaviors and their influential factors. The results indicate that consumers who engage in recycling, pro‐environmental post‐purchasing behavior and pro‐environmental activities are highly educated people. Among them, those who are mostly involved in recycling and the non‐energetic, rather traditional, activities are mostly influenced by their positive attitudes towards recycling, as well as by their social responsibility. Those who adopt more energetic, more active, behaviors are mostly influenced by their beliefs that they hold power over politicians and politics. It was also found that those who are engaged in one type of non‐purchasing pro‐environmental behavior are more likely to engage in another type as well. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.
Intermittent hypobaric hypoxia‐induced oxidative stress in rat erythrocytes: protective effects of vitamin E, vitamin C, and carnitine
Authors: Devi S. Asha , Vani R. , Subramanyam M. V. V. , Reddy Shiva Shankar , Jeevaratnam K. 
Published: July 2006

AbstractThis study was aimed at determining the effect of vitamin E, vitamin C, and carnitine on intermittent hypobaric‐hypoxia‐induced oxidative stress (OS) in erythrocytes. For this purpose, male Wistar rats of 4 months of age were orally supplemented with one of the antioxidants prior to exposure to altitudes of 5700 m or 6300 m. Hemoglobin (Hb) and OS indices such as osmotic fragility and hemolysis were measured together with lipid peroxidation (LPO) and protein oxidation. The increase in Hb was accompanied by increase in activities of antioxidant enzymes, superoxide dismutase (SOD), and catalase (CAT) during exposure to both the altitudes without any further elevation by supplements. The extent of reduction in osmotic fragility and hemolysis by vitamin E and carnitine was greater at 6300 m than at 5700 m. Increase in LPO products, for example, malondialdehyde (MDA) and lipofuscin‐like autofluorescent substances (AFS) was noticeable at both the altitudes, and vitamin E and carnitine were effective in reducing LPO. While protein oxidation products such as carbonyl content (PrC) and advanced oxidation protein products (AOPP) increased at 6300 m, protein sulphydryl (P‐SH) content decreased. P‐SH levels were restored on supplementation of antioxidants. Hence, our results indicate that vitamin E, vitamin C, and carnitine may be beneficial in overcoming OS and hemolysis under situations such as intermittent hypobaric hypoxia (IHH) and hypobarotherapy wherein hypoxia is used to correct many pathological situations in humans. Further, this study suggests that supplementation of vitamin E, vitamin C, and L‐carnitine alone and not in combination can be beneficial in attenuating the OS associated with IHH compared to the unsupplemented rats exposed to two different altitudes. Copyright © 2006 John Wiley & Sons, Ltd.