bluuebunny/crossref_metadata_2025_split huggingface dataset:
A continued‐fraction‐based high‐order transmitting boundary for wave propagation in unbounded domains of arbitrary geometry
Authors: Bazyar Mohammad Hossein , Song Chongmin 
Published: July 2007

AbstractA high‐order local transmitting boundary is developed to model the propagation of elastic waves in unbounded domains. This transmitting boundary is applicable to scalar and vector waves, to unbounded domains of arbitrary geometry and to anisotropic materials. The formulation is based on a continued‐fraction solution of the dynamic‐stiffness matrix of an unbounded domain. The coefficient matrices of the continued fraction are determined recursively from the scaled boundary finite element equation in dynamic stiffness. The solution converges rapidly over the whole frequency range as the order of the continued fraction increases. Using the continued‐fraction solution and introducing auxiliary variables, a high‐order local transmitting boundary is formulated as an equation of motion with symmetric and frequency‐independent coefficient matrices. It can be coupled seamlessly with finite elements. Standard procedures in structural dynamics are directly applicable for evaluating the response in the frequency and time domains. Analytical and numerical examples demonstrate the high rate of convergence and efficiency of this high‐order local transmitting boundary. Copyright © 2007 John Wiley & Sons, Ltd.
HMM‐based surface reconstruction from single images
Authors: Nagai Takayuki , Ikehara Masaaki , Kurematsu Akira 
Published: July 2007

AbstractIn this paper, a novel method of surface reconstruction from a single monocular image is proposed. Our proposed approach (called “shape from object‐specific knowledge”) is based on knowledge of objects, acquired by learning from a number of samples. To achieve this, we investigate the use of the Subband Pseudo 2D Hidden Markov Model (SPHMM), which is an extended version of normal Pseudo 2D HMMs. SPHMMs can model the correspondence between an intensity image and its depth information. We have applied our algorithm to 3D face, 3D hand, and 3D car reconstruction from single images, and the results show the effectiveness of the proposed method. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(11): 80–89, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10685
Changes in dielectric constant as a measure of frying oil deterioration
Authors: Fritsch C. W. , Egberg D. C. , Magnuson J. S. 
Published: July 2007

AbstractA soybean oil, a hydrogenated vegetable frying shortening and an animal‐vegetable shortening were heated at 190 C for 8 hours each day for 4 days with and without the frying of potatoes. Samples were taken periodically and analyzed for various changes normally used to measure frying oil deterioration. The changes in the dielectric constant were determined with a patented instrument called the Food Oil Sensor. This instrument is standardized with 3. sample of the fresh oil, and it then measures the change in the electric capacitance of the heated oil samples. The dielectric constant of all three shortenings increased linearly with heating time. The greatest change occurred in the soybean oil sample and the smallest change in the hydrogenated vegetable shortening. For each shortening the increase was somewhat greater during frying than during heating without frying. Statistically significant correlations were obtained between instrument readings and increase in the total polar materials, the color, the peroxide values, the diene content, and the free fatty acids and the decrease in the iodine values.
Formulating characteristics of high and low 2‐phenyl linear alkylbenzene sulfonates in liquid detergents
Authors: Drozd Joseph C. , Gorman Wilma 
Published: July 2007

AbstractDetergent range linear alkylbenzene (LAB) currently is manufactured by two different processes, using either aluminum chloride or hydrogen fluoride as the alkylation catalyst. The alkylates from the two processes are not exactly the same. Furthermore, the properties of the linear alkylbenzene sulfonate (LAS) surfactants made by sulfonation of the LABs also differ. Because LAS is used in most types of detergent products, it is important to known how the properties of each type of LAS differ. This paper compares the formulating characteristics (such as viscosity, solubility and foaming) of high and low 2‐phenyl LAS in some typical household cleaning product formulations. It is concluded that the two types of LAS should not be used interchangeably without first checking carefully all the physical properties required in a product.
An analysis of the relationship between plasma urea and ammonia concentration in dairy cattle fed a consistent diet over a 100-day period
Authors: Laven Richard A , Claire Wathes D , Lawrence Kevin E , Scaramuzzi Rex J 
Published: July 2007

Measurement of plasma urea concentration is often used to identify a risk of dietary nitrogen-associated infertility. However, the use of plasma urea concentration in this way relies on it being an effective predictor for other potential toxic products associated with nitrogen metabolism (such as plasma or uterine ammonia). Recent research has shown that dietary nitrogen-associated infertility can be produced by diets which elevate plasma ammonia concentration without markedly increasing plasma urea concentration. Thus for cattle on different diets plasma urea concentration cannot be used to predict plasma ammonia concentration. This study evaluated whether plasma urea concentration could be used to predict plasma ammonia concentration in cattle kept on consistent diets. Data were analysed from a study where 42 cattle had been fed a control diet or the control diet plus 250 g urea per cow per day and had had weekly measurements of post-prandial plasma urea and ammonia concentrations. This analysis found that over a 100-d period, plasma urea concentration was relatively constant and unaffected by time while plasma ammonia concentration was significantly more variable, being affected by time since the study started, and whether cows began the study in the first or second group. Correlation between plasma ammonia and urea was limited; plasma urea concentration explained only 3·8% of the variation in plasma ammonia concentration. These data suggest that, even in cows on consistent diets, plasma urea concentration is not a good predictor of plasma ammonia, and that a simple urea threshold may not accurately identify the risk of dietary nitrogen-associated infertility.
Bourbon Intervention in the Peruvian Tobacco Industry, 1752–1813
Authors: VIZCARRA CATALINA 
Published: July 2007

AbstractDuring the second half of the eighteenth century the Spanish Crown monopolised the tobacco industry in its American colonies, creating vertically integrated organisations which included factories for the production of cigars and cigarettes. A detailed analysis of the regulations, organisation and policies applied during the Peruvian viceroyalty suggests that Bourbon officials were effective managers. The monopoly was successful at curbing contraband and extracting rents. The evolution of monopoly policies, however, reflected political constraints on the Crown's efforts to raise revenues. The archival evidence suggests that Bourbon officials closed the tobacco factories in Peru in 1791 as a result of public opposition.
Functional connectivity in the brain and human intelligence
Authors: Schmithorst Vincent J. 
Published: July 2007

AbstractA parieto-frontal integration theory (P-FIT) model of human intelligence has been proposed based on a review of neuroimaging literature and lesion studies. The P-FIT model provides an important basis for future research. Future studies involving connectivity analyses and an integrative approach of imaging modalities using the P-FIT model should provide vastly increased understanding of the biological bases of intelligence.
Beautiful minds (i.e., brains) and the neural basis of intelligence
Authors: Haier Richard J. , Jung Rex E. 
Published: July 2007

AbstractThe commentaries address conceptual issues ranging from our narrow focus on neuroimaging to the various definitions of intelligence. The integration of the P-FIT and data from cognitive neuroscience is particularly important and considerable consistency is found. Overall, the commentaries affirm that advances in neuroscience techniques have caused intelligence research to enter a new phase. The P-FIT is recognized as a reasonable empirical framework to test hypotheses about the relationship of brain structure and function with intelligence and reasoning.
The nature and origin of pegmatites in a fluorine-rich leucogranite, East Kemptville Tin Deposit, Nova Scotia, Canada
Authors: Kontak Daniel J. , Ansdell Kevin , Dostal Jaroslav , Halter Werner , Martin Robert , Williams-Jones Anthony E. 
Published: July 2007

ABSTRACTPegmatites at the East Kemptville Sn-Zn-Cu-Ag deposit occur within a F- and P-rich, 370 Ma topaz-muscovite leucogranite, the most evolved phase of the chemically zoned Davis Lake Pluton. Structural observations and geochronology indicate that the leucogranite intruded into an active shear/fault zone environment. Pegmatites are preferentially located near the roof zone of the intrusion and include: (1) quartz-feldspar pods (≤ 1–2 m) aligned parallel to a foliation in the leucogranite. Such pegmatites have marginal aplites or may be cored by aplites; (2) aplite-pegmatite zones with well-developed crenulate and unidirectional solidification textures; and (3) muscovite-bordered miarolitic cavities lined with quartz-feldspar ± cassiterite. Associated with areas of pegmatites are irregular- to cuspate-shaped zones enriched in muscovite. Mineralogically the pegmatites are simple, consisting of clear to black quartz, albite, microcline perthite and muscovite; topaz may be enriched in aplites coring pegmatites and coarse euhedral cassiterite is rare.Chemically the leucogranites marginal to pegmatites are similar to the host leucogranite, but some aphanitic felsic dykes indicate extreme differentiation, as reflected by REE depletion and P-enrichment. Enrichment of pegmatitic feldspar in P2O5 (to 1 wt. %) indicates that melts contained 2–3 wt. % P2O5, whereas muscovite chemistry (to 5 wt. % F) reflects the F-rich nature of the melt. Trace and REE contents of pegmatitic feldspars are consistent with local segregation of volatile-rich melts to form pegmatites rather than extreme crystal-chemical fractionation.Fluid inclusion studies of pegmatitic quartz and cassiterite indicate the presence of a highly saline brine (40 wt. % eq. NaCl; Na > K > Fe > Mn > Ca > Sr) of magmatic origin. Isochores modelled for a 40 wt. % eq. NaCl fluid constrain pegmatite formation at 550–600°C, thus the depressed solidus is consistent with the volatile-rich (F, P, H2O) nature of the melt. Stable isotopes demonstrate that a magmatic fluid (δ18OH2O = +5·5 to +10‰, δDH2O = −33 to −41‰ for 450–500°C) equilibrated with the pegmatites and the system cooled abruptly at c. 425°C.The low volume of pegmatite at East Kemptville suggests that the melt was not near volatile saturation, instead pegmatite generation is interpreted to have resulted from rapid decompression related to the active shear zone setting of the granite. Although feldspar chemistry reflects a local segregation model, the chemistry of aphanitic dyke rocks indicates that the leucogranite did evolve into a more fractionated melt. The local presence of cassiterite in pegmatites and miarolitic cavities indicates that locally, saturation of Sn occurred, but not throughout the EKL where elevated Sn contents are attributed to infiltration of mineralising fluids (i.e. deuteric alteration).
Towards a unified model for granite genesis
Authors: Chappell B. W. 
Published: July 2007

ABSTRACTMost granites result from partial melting within the crust. Granite melts produced at the lowest temperatures of partial melting mainly comprise close to equal amounts of the haplogranite components Qz, Ab and Or, with H2O. Many felsic granites were formed by partial melting under such conditions and are low-temperature types, with crystals of zircon and other restite minerals present in the initial magma. Such magmas evolve in composition, at least initially, through fractionation of that restite. If one of the four haplogranite components either becomes depleted or too low in amount to contribute further to the melt, then melting may proceed to higher temperatures without a contribution from that component. Melting will advance to significantly higher temperatures if there is a critical deficiency in one or more components and a high-temperature granite magma forms, in which zircon is completely soluble. Such magmas are extracted from the source in a completely molten state and may evolve by fractional crystallisation. They are monzonitic, tonalitic or A-type, depending on whether the critical deficiency occurred in the Qz, Or or H2O component. If the Ab component is critically deficient, as in pelitic rocks, the rocks may be infertile for granite production. The control that source rock compositions exert on both the physical and chemical properties of granite magmas provides a unifying element in granite gen
Timing of Early Proterozoic magmatism along the Southern margin of the Siberian Craton (Kitoy area)
Authors: Poller Ulrike , Gladkochub D. P. , Donskaya T. V. , Mazukabzov A. M. , Sklyarov E. V. , Todt W. 
Published: July 2007

ABSTRACTSeveral granites and basement gneisses along the southern margin of the Siberian Craton were sampled to obtain precise age constrains and compositional isotopic data. The analysed granite plutons are interpreted to have been emplaced between 1880 and 1850 Ma, and are related to Palaeoproterozoic collisional and post-collisional events. Pb-Pb whole data of a granulite (1884 ± 26 Ma) and a two mica granite (1821 ± 29 Ma) constrain these U-Pb single zircon ages. Sr, Nd and Pb-Pb isotope data reveal the crustal origin of the investigated rocks and the reworking of Archaean material. Nevertheless, a minor influence of a mantle component is still visible in the Pb isotopes. Geodynamically, the magmatic and metamorphic ages in the Kitoy area are linked to several Early Proterozoic events along the southern margin of the Siberian Craton. Since these events are all older than the assembly of Rodinia (about 1·4 Ga ago) the collisional processes are linked to the consolidation of the Siberian Craton itself in Early Proterozoic times.
A model of reconstruction for the oral apparatus of the Ordovician conodont genus Protopanderodus Lindström, 1971
Authors: Mellgren Johanna S. , Eriksson Mats E. 
Published: July 2007

ABSTRACTElements of the Ordovician conodont genus Protopanderodus have been investigated in order to provide a model of reconstruction for its oral apparatus. In total, 4,202 elements from the five named species representing this genus in the Swedish Middle Ordovician are included in this study: P. rectus, P. parvibasis, P. graeai, P. robustus and P. calceatus. The well-preserved specimens were studied in detail for identification of distinct element types and calculations were made to determine element ratios and minimum number of elements in a single apparatus. Three element groups, M, S and P, were recognised for all five species and their relative ratio is indicative of apparatuses consisting of at least 21 elements. However, the number of element types and their distribution varies between the species. The four bicostate species, P. rectus, P. parvibasis, P. graeai and P. robustus, have similar morphological characters and are believed to belong to the same evolutionary lineage. They possessed apparatuses consisting of M, Sa, Sb1, Sb2, Sc, Pa and Pb elements. By contrast, the multicostate species P. calceatus is morphologically different and had an apparatus consisting of M1, M2, Sa, Sb, Sc, “Sd”, Pa, Pb1 and Pb2 elements. These differences indicate that P. calceatus is not so closely related to the other species, possibly representing a separate evolutionary lineage, and may warrant an exclusive generic assignment.
Tracing the Structure‐Function Relationship of Neuroglobin and Cytoglobin using Resonance Raman and Electron Paramagnetic Resonance Spectroscopy
Authors: Van Doorslaer S. , Vinck E. , Trandafir F. , Ioanitescu I. , Dewilde S. , Moens L. 
Published: July 2007

AbstractThe physiological role of neuroglobin and cytoglobin, two vertebrate globins discovered in the last 5 years, is not yet clearly understood. In this work, we review the structural information on these globins and its implication on the possible protein functions, obtained by electron paramagnetic resonance and resonance Raman spectroscopy. All studies reveal a high flexibility in the heme‐pocket region of neuroglobin. Together with the observation that the distal ligand of the heme iron is the endogenous E7‐histidine in both the ferric and ferrous form of neuroglobin and cytoglobin, the flexibility of the heme environment in neuroglobin will play a crucial role in the globins' ability to bind and stabilize exogenous ligands.
IUBMB Life, 56: 665‐670, 2004
Physical‐chemical determinants of turn conformations in globular proteins
Authors: Street Timothy O. , Fitzkee Nicholas C. , Perskie Lauren L. , Rose George D. 
Published: July 2007

AbstractGlobular proteins are assemblies of α‐helices and β‐strands, interconnected by reverse turns and longer loops. Most short turns can be classified readily into a limited repertoire of discrete backbone conformations, but the physical–chemical determinants of these distinct conformational basins remain an open question. We investigated this question by exhaustive analysis of all backbone conformations accessible to short chain segments bracketed by either an α‐helix or a β‐strand (i.e., α‐segment‐α, β‐segment‐β, α‐segment‐β, and β‐segment‐α) in a nine‐state model. We find that each of these four secondary structure environments imposes its own unique steric and hydrogen‐bonding constraints on the intervening segment, resulting in a limited repertoire of conformations. In greater detail, an exhaustive set of conformations was generated for short backbone segments having reverse‐turn chain topology and bracketed between elements of secondary structure. This set was filtered, and only clash‐free, hydrogen‐bond–satisfied conformers having reverse‐turn topology were retained. The filtered set includes authentic turn conformations, observed in proteins of known structure, but little else. In particular, over 99% of the alternative conformations failed to satisfy at least one criterion and were excluded from the filtered set. Furthermore, almost all of the remaining alternative conformations have close tolerances that would be too tight to accommodate side chains longer than a single β‐carbon. These results provide a molecular explanation for the observation that reverse turns between elements of regular secondary can be classified into a small number of discrete conformations.
Reactivation of methionine synthase from Thermotoga maritima (TM0268) requires the downstream gene product TM0269
Authors: Huang Sha , Romanchuk Gail , Pattridge Katherine , Lesley Scott A. , Wilson Ian A. , Matthews Rowena G. , Ludwig Martha 
Published: July 2007

AbstractThe crystal structure of the Thermotoga maritima gene product TM0269, determined as part of genome‐wide structural coverage of T. maritima by the Joint Center for Structural Genomics, revealed structural homology with the fourth module of the cobalamin‐dependent methionine synthase (MetH) from Escherichia coli, despite the lack of significant sequence homology. The gene specifying TM0269 lies in close proximity to another gene, TM0268, which shows sequence homology with the first three modules of E. coli MetH. The fourth module of E. coli MetH is required for reductive remethylation of the cob(II)alamin form of the cofactor and binds the methyl donor for this reactivation, S‐adenosylmethionine (AdoMet). Measurements of the rates of methionine formation in the presence and absence of TM0269 and AdoMet demonstrate that both TM0269 and AdoMet are required for reactivation of the inactive cob(II)alamin form of TM0268. These activity measurements confirm the structure‐based assignment of the function of the TM0269 gene product. In the presence of TM0269, AdoMet, and reductants, the measured activity of T. maritima MetH is maximal near 80°C, where the specific activity of the purified protein is ∼15% of that of E. coli methionine synthase (MetH) at 37°C. Comparisons of the structures and sequences of TM0269 and the reactivation domain of E. coli MetH suggest that AdoMet may be bound somewhat differently by the homologous proteins. However, the conformation of a hairpin that is critical for cobalamin binding in E. coli MetH, which constitutes an essential structural element, is retained in the T. maritima reactivation protein despite striking divergence of the sequences.
Causes and consequences of winter mortality in fishes
Authors: Hurst T. P. 
Published: July 2007

Winter mortality has been documented in a large number of freshwater fish populations, and a smaller, but increasing, number of marine and estuarine fishes. The impacted populations include a number of important North American and European resource species, yet the sources of winter mortality remain unidentified in most populations where it has been documented. Among the potential sources, thermal stress and starvation have received the most research attention. Other sources including predation and pathogens have significant impacts but have received insufficient attention to date. Designs of more recent laboratory experiments have reflected recognition of the potential for interactions among these co‐occurring stressors.Geographic patterns in winter mortality are, in some cases, linked to latitudinal clines in winter severity and variability. However, for many freshwater species in particular, the effects of local community structure (predators and prey) may overwhelm latitudinal patterns. Marine (and estuarine) systems differ from freshwater systems in several aspects important to overwintering fishes, the most important being the lack of isolating barriers in the ocean. While open population boundaries allow fish to adopt migration strategies minimizing exposure to thermal stresses, they may retard rates of evolution to local environments. Geographic patterns in the occurrence and causes of winter mortality are ultimately determined by the interaction of regional and local factors.Winter mortality impacts population dynamics through episodic depressions in stock size and regulation of annual cohort strength. While the former tends to act in a density‐independent manner, the latter can be density dependent, as most sources of mortality tend to select against the smallest members of the cohort and population. Most stock assessment and management regimes have yet to explicitly incorporate the variability in winter mortality. Potential management responses include postponement of cohort evaluation (to after first winter of life), harvest restrictions following mortality events and habitat enhancement.Future research should place more emphasis on the ecological aspects of winter mortality including the influences of food‐web structure on starvation and predation. Beyond illuminating an understudied life‐history phase, studies of overwintering ecology are integral to contemporary issues in fisheries ecology including ecosystem management, habitat evaluation, and impacts of climate change.