bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bipolar, anastral spindle development in artificially activated sea urchin eggs
Authors: Henson John H. , Fried Christopher A. , McClellan Mary K. , Ader Jason , Davis Jessica E. , Oldenbourg Rudolf , Simerly Calvin R. 
Published: April 2008

AbstractThe mitotic apparatus of the early sea urchin embryo is the archetype example of a centrosome‐dominated, large aster spindle organized by means of the centriole of the fertilizing sperm. In this study, we tested the hypothesis that artificially activated sea urchin eggs possess the capacity to assemble the anastral, bipolar spindles present in many acentrosomal systems. Control fertilized Lytechinus pictus embryos and ammonia‐activated eggs were immunolabeled for tubulin, centrosomal material, the spindle pole structuring protein NuMA and the mitotic kinesins MKLP1/Kinesin‐6, Eg5/Kinesin‐5, and KinI/Kinesin‐13. Confocal imaging showed that a subset of ammonia‐activated eggs contained bipolar “mini‐spindles” that were anastral; displayed metaphase and anaphase‐like stages; labeled for centrosomal material, NuMA, and the three mitotic kinesins; and were observed in living eggs using polarization optics. These results suggest that spindle structural and motor proteins have the ability to organize bipolar, anastral spindles in sea urchin eggs activated in the absence of the paternal centriole. Developmental Dynamics 237:1348‐1358, 2008. © 2008 Wiley‐Liss, Inc.
Crystal Structure and Magnetism of the 6H Hexagonal Double Perovskites Ba2FeSbO6 and Ba2CoSbO6–δ: A Neutron Diffraction and Mössbauer Spectroscopy Study
Authors: Retuerto M. , Alonso J. A. , Martínez‐Lope M. J. , García‐Hernández M. , Krezhov K. , Spirov I. , Ruskov T. , Fernández‐Díaz M. T. 
Published: April 2008

AbstractBa2MSbO6–δ (M = Fe, Co) double perovskites have been prepared in polycrystalline form by the solid‐state reaction in air and characterized by X‐ray diffraction (XRD), neutron powder diffraction (NPD), magnetic measurements and Mössbauer spectroscopy (for M = Fe). At room temperature, the crystal structure of both compounds can be defined as a 6‐layered (6H) hexagonal perovskite structure (space group P63/mmc), with a = 5.7875(1) Å and c = 14.2104(2) Å for M = Fe and a = 5.7548(2) Å and c = 14.1439(7) Å for M = Co. M and Sb cations are randomly distributed over 4f and 2a Wickoff positions. The crystal structure is constituted by dimer units of (M,Sb)4fO6 octahedra sharing a face along the c axis; the dimers, which sharing corners, are connected by a single layer of (M,Sb)2aO6 octahedra. A severe degree of antisite disordering was detected in the Fe compound, which indicates the presence of 52.8 % Fe:47.2 % Sb at the (Fe,Sb)2a positions, whereas for Co, 64.0 % Sb is present at the(Co,Sb)2a sites. Mössbauer spectroscopic data for Ba2FeSbO6 confirm the existence of two distinct crystallographic sites for Fe3+. One site corresponds to very regular FeO6 octahedra (at 2a positions), which gives rise to a singlet in the Mössbauer spectra at room temperature and 77 K that is broadened by the strong Fe/Sb disorder over this site. The second environment for Fe3+ contributes to a broadened doublet in the Mössbauer spectra, which corresponds to a very distorted FeO6 octahedron (at 4f sites), for which neutron powder diffraction data demonstrates an axial distortion with two sets of Fe–O distances. This distortion is due to the repulsion of the highly charged Sb5+ cations within the dimer units of the (Fe,Sb)4fO6 octahedra, and it is much reduced in the Co compound, where the amount of Sb5+ at these sites is smaller. Magnetic measurements suggest the absence of long‐range magnetic ordering for both samples, which is confirmed by low‐temperature neutron diffraction data. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Enzyme‐based approaches for pitch control in thermomechanical pulping of softwood and pitch removal in process water
Authors: Dubé Etienne , Shareck François , Hurtubise Yves , Beauregard Marc , Daneault Claude 
Published: April 2008

AbstractBACKGROUND: In the pulp and paper manufacturing process, pitch colloidal particles have a tendency to agglomerate and deposit on pulp fibres and equipments. They reduce the efficiency of the washer, increase the dirt count and bleach chemical consumption, reduce pulp brightness thus leading to paper defects. Triglycerides are considered to be the most problematic compounds during the manufacturing of mechanical and acidic sulfite pulps from various softwood species.RESULTS: Using enzyme‐based approaches, a pitch control method was developed for use with thermomechanical pulping of softwood and for pitch removal from process water. Results showed that with combination of a novel biodegradable surfactant and a lipase resin acids, sterols and triglyceride groups were reduced by 48%, 32% and 78%, respectively, compared with untreated samples. Using laccase treatment of the process water the fatty and resin acids were reduced by 42% and the lignans by 60%.CONCLUSION: By combining the proposed pulp treatment with laccase decontamination of the process water, this new method offers an efficient alternative to control the various pitch‐associated problems. Copyright © 2008 Society of Chemical Industry
Nitrogen mineralization of leguminous crops in soils
Authors: Nakhone Lenah N. , Tabatabai M. Ali 
Published: April 2008

AbstractOrganic‐N production by legumes is a key benefit of growing cover crops and green manures. A soil sample was mixed with legume residue commonly used as green manure in Kenya at a rate of 500 mg N (kg soil)–1. Silica sand equal to the weight of the soils was added and mixed thoroughly. The mixture was packed in a leaching tube and leached with 100 mL of 5 mM of CaCl2 . 2H2O and incubated at 30°C. The leaching was repeated every 2 weeks for a total of 16 weeks and analyzed for N as NH$ _4^+ $, NO$ _3^- $, and NO$ _2^- $. Five legume residues and five different soils were used in this study. Nitrogen mineralization of the legume residues conformed to an exponential model. Application of a two‐components exponential model showed two phases of N mineralization. The relationship between the organic N remaining after each incubation period and time of incubation was controlled by two first‐order reactions. The initial fast rate (k1) changed to a slow rate (k2) at incubation times ranging from 2 to 8 weeks, depending on the legume residue and the soil used. The percentage of N in each phase varied among the legume residue and soils. Linear regression analyses showed that net cumulative amounts of N mineralized from individual legume residues was significantly correlated with the total polyphenols and polyphenol‐to‐N ratios for two soils. Nitrogen mineralization of dolichos and field bean was significantly and negatively correlated with clay and sand, respectively; of field bean and alfalfa was significantly correlated with Cmic; and of dolichos significantly but negatively correlated with the total N and organic N in soils. Linear regression analysis of the pooled data showed that net cumulative amounts of N mineralized and percentage N mineralized were significantly correlated with C : N ratios of the residues (r = 0.44 and 0.48 at p < 0.05, respectively), and that net cumulative N mineralized was significantly correlated with (lignin + polyphenols)‐to‐N ratios (r = 0.41 at p < 0.05) and with lignin contents (r = 0.61 at p < 0.001).
Understanding the patterns and distribution of opioid analgesic dependence symptoms using a latent empirical approach
Authors: Ghandour L.A. , Martins S.S. , Chilcoat H.D. 
Published: April 2008

AbstractPrevalence of extramedical opioid analgesic use in the US is rising, yet little is known about the nature and extent of problems of dependence related to the use of these drugs. This study uses Latent Class Analysis to empirically define classes of past‐year extramedical opioid analgesic users based on observed clustering of DSM‐IV defined clinical dependence features; multinomial logistic regression is used to describe differences across these groups. The 2002–2003 public data‐files of the National Survey on Drug Use and Health were used to identify 7810 extramedical opioid analgesic users in the past‐year. The best‐fitting four‐class model identified classes that differed quantitatively and qualitatively, with 2% of the users in Class 4 (most severe) and 84% in Class 1 (least severe). Classes 2 and 3 had parallel symptom profiles, but those in Class 3 reported additional problems. Adolescents (12–17 year olds) were at higher odds of being in Class 3 versus older age groups; females were two times as likely to be in Classes 2 and 4, and those with mental health problems were at higher odds of belonging to the more severe classes. Differences by type of past year opioid users were also detected. This study sheds light on the classification and distribution of extramedical opioid analgesic dependence symptoms in the US general population, identifying subgroups that warrant immediate attention. Copyright © 2008 John Wiley & Sons, Ltd.
An evaluation of the outsourcing IS/ICT activities in Turkish ministerial computer departments
Authors: Bensghir Turksel Kaya , Tekneci Ali 
Published: April 2008

AbstractOutsourcing an IS/ICT function has become fashionable in public administration reform. Through this modality, many organisations are cutting staff costs and increasing efficiency. Financial benefits can be great, public organisations can in fact expand IT usage and hence avoid obsolescence. Despite the benefits of outsourcing IT, there are risks involved. Public organisations need to weigh the benefits, risks and costs involved before making decisions to outsource.Recently, Turkish public organisations have been increasingly outsourcing functions such as facilities maintenance, catering, security and IS/ICT activities. This article, based on a field study, undertakes an evaluation of the experience of Chief Information Officers (CIO's) in outsourcing of IS/ICT activities in ministerial computer departments. The findings provide important lessons for outsourcing in Turkey and elsewhere. Copyright © 2008 John Wiley & Sons, Ltd.
Moderate temperature sol–gel deposition of magnesium fluoride films for optical UV‐applications:A study on homogeneity using spectroscopic ellipsometry
Authors: Krüger Hannes , Kemnitz Erhard , Hertwig Andreas , Beck Uwe 
Published: April 2008

AbstractThin films of MgF2 have been deposited on silicon wafers in optical quality with a novel sol–gel deposition process at temperatures as low as 100 °C. The properties of the fluoride layers are compared to bulk MgF2 with respect to the optical constants. By employing spectroscopic mapping ellipsometry, the uniformity of the thickness of fluoride layers is confirmed to be within acceptable limits for optical applications. The optical constants are close to the bulk data. High‐quality low‐index films of suitable and homogeneous thickness have already been produced on a laboratory scale. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Observation of quantum confinement and quantum size effects
Authors: Diebold A. C. , Price J. 
Published: April 2008

AbstractRecently, the change in optical properties of ultra‐thin silicon on insulator films was shown to be due to quantum confinement. The E1 critical point shifted to higher energies with a 1/L2 dependence, and the shift was observed room temperature. Yet, quantum confinement effects in thin metal have yet to be observed optically. This leads to a number of questions that we raise and for which we provide preliminary answers. Shifts less than kT in energy can be observed optically when the final state is spatially and temporally localized. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Plasma ion implantation to thin polymer foils
Authors: Tian X. B. , Huang Y. X. , Li J. , Yang S. Q. , Chu Paul K. , Fu Ricky K. Y. 
Published: April 2008

AbstractPlasma ion implantation and deposition of polymeric materials has gained substantial interest in recent years. This paper will present numerical results on initial potential on top surface and some examples on ion implantation of thin polymer foils. The results demonstrate that the thickness and permittivity of treated samples have a critical influence on initial potential drop across the insulating objects. The smaller thickness and larger permittivity are beneficial for ion implantation. Duplex films of Al2O3/SiO2 have been fabricated using arc plasma ion implantation and deposition. The films may substantially increase atomic‐oxygen resistance of Kapton foils, which have been frequently utilized in satellites in low‐earth‐orbit (LEO) environment. The mass loss of treated samples may decrease by one quarter of magnitude compared to that of control sample. The PET foils have also been implanted using C2H2 plasma ion implantation. The experimental results show that ion implantation may effectively enhance the gas barrier capability. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Parametric photoluminescence of spatially confined polaritons in patterned microcavities
Authors: Portolan S. , Hauke P. , Savona V. 
Published: April 2008

AbstractWe model the parametric photoluminescence process of laterally confined polaritons in a mesa structure, patterned on a semiconductor microcavity. Parametric processes are described within the lowest order in the polariton–polariton interaction. We show how a plane‐wave pump produces simultaneously several signal–idler pairs, due to the broken translational symmetry, the finite polariton linewidths, and the presence of a continuum of polariton states above the shallow mesa barrier. We discuss under which conditions of pump and detuning, the simple three‐mode picture for the parametric process is recovered. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preferred structures in large‐scale circulation and the effect of doubling greenhouse gas concentration in HadCM3
Authors: Hannachi A. , Turner A. G. 
Published: April 2008

AbstractPreferred structures in the surface pressure variability are investigated in and compared between two 100‐year simulations of the Hadley Centre climate model HadCM3. In the first (control) simulation, the model is forced with pre‐industrial carbon dioxide concentration (1 × CO2) and in the second simulation the model is forced with doubled CO2 concentration (2 × CO2). Daily winter (December–January–February) surface pressures over the Northern Hemisphere are analysed. The identification of preferred patterns is addressed using multivariate mixture models. For the control simulation, two significant flow regimes are obtained at 5% and 2.5% significance levels within the state space spanned by the leading two principal components. They show a high pressure centre over the North Pacific/Aleutian Islands associated with a low pressure centre over the North Atlantic, and its reverse. For the 2 × CO2 simulation, no such behaviour is obtained. At higher‐dimensional state space, flow patterns are obtained from both simulations. They are found to be significant at the 1% level for the control simulation and at the 2.5% level for the 2 × CO2 simulation. Hence under CO2 doubling, regime behaviour in the large‐scale wave dynamics weakens. Doubling greenhouse gas concentration affects both the frequency of occurrence of regimes and also the pattern structures. The less frequent regime becomes amplified and the more frequent regime weakens. The largest change is observed over the Pacific where a significant deepening of the Aleutian low is obtained under CO2 doubling. Copyright © 2008 Royal Meteorological Society
Potential energy surfaces for H2 dissociative adsorption on Pt(111) surface—effects of vacancies
Authors: Arboleda Nelson B. , Kasai Hideaki 
Published: April 2008

AbstractIn this study, we determine the effects of having vacancies on the Pt(111) surface to the dissociative adsorption behavior of H2 on Pt(111). We study the potential energy behaviors along the reaction paths based on the potential energy surfaces (PESs) we calculated that are relevant to these systems. Partial results of our current calculations, based on the density functional theory, reveal that vacancies on the substrate can significantly lower the barrier for the dissociative adsorption of H2 on the Pt(111) surface. We attribute this behavior to the increased reactivity of the surface owing to the vacant sites. Of the substrate atoms, we find that those on the surface mainly influence the behavior of H2 adsorption on Pt(111). Copyright © 2008 John Wiley & Sons, Ltd.
Gender, victimization, and psychiatric outcomes
Authors: Gershon A. , Minor K. , Hayward C. 
Published: April 2008

BackgroundAlthough gender differences in rates of internalizing disorders, particularly depression, are well documented, the causes of these differences are not well understood. One influential hypothesis [Cutler & Nolen-Hoeksema, Sex Roles (1991), 24, 425–438] proposes that higher rates of depression in females compared to males may be partially attributable to gender differences in the effects of childhood sexual abuse. The present study has evaluated this possibility by reviewing evidence for gender moderating the effects of childhood victimization on psychiatric outcomes.MethodLiterature search using PsycINFO and Medline, applying the following inclusion criteria: publication from 1996 to 2006, community-based sampling, adequate male-to-female sample ratio, use of clearly defined psychiatric outcomes, and a statistical test of gender differences in the effects of childhood victimization on psychiatric outcomes.ResultsThirty studies met inclusion criteria. Overall, the results were mixed. Nearly half of all studies find no gender differences. In studies that do observe gender differences, victimization tends to be associated with higher psychiatric risk in females in studies with adult samples, whereas in samples of youth, victimization tends to be associated with higher psychiatric risk in males. With respect to outcome, when gender differences were observed, outcomes were distributed across both internalizing and externalizing categories for both genders.ConclusionsThe gender differences in prevalence rates of internalizing disorders, such as depression, do not appear to be attributable to differential effects of childhood victimization.
The organization and rise of land and lease markets in northwestern Europe and Italy, c. 1000–1800
Authors: VAN BAVEL B. J. P. 
Published: April 2008

ABSTRACTIn the course of the late Middle Ages and early modern period, in Western Europe, ways of transferring and redistributing land outside the market were replaced by market transactions. This, however, was by no means a general and unilinear process, but one that displays strong regional differences and temporal discontinuities. This article aims to gain more insight in the factors underlying these differences, by reconstructing and analysing the institutional organization of exchange in land and lease markets. The analysis, undertaken for northwestern Europe and Italy, points to the socio-political context as a main determinant of this organization.
Magnitude of bacteraemia is a predictor of mortality during 1 year of follow-up
Authors: GRADEL K. O. , SØGAARD M. , DETHLEFSEN C. , NIELSEN H. , SCHØNHEYDER H. C. 
Published: April 2008

SUMMARYWe evaluated magnitude of bacteraemia as a predictor of mortality, comprising all adult patients with a first-time mono-microbial bacteraemia. The number of positive bottles [1 (reference), 2, or 3] in the first positive blood culture (BC) was an index of magnitude of bacteraemia. We used Cox's regression analysis to determine age and comorbidity adjusted risk of mortality at days 0–7, 8–30, and 31–365. Of 6406 patients, 31·1% had BC index 1 (BCI 1), 18·3% BCI 2, and 50·6% BCI 3. BCI 3 patients had increased risk of mortality for days 0–7 (1·30, 95% CI 1·10–1·55) and days 8–30 (1·37, 95% CI 1·12–1·68), but not thereafter. However, in surgical patients mortality increased only beyond day 7 (8–30 days: 2·04, 95% CI 1·25–3·33; 31–365 days: 1·27, 95% CI 0·98–1·65). Thus, high magnitude of bacteraemia predicted mortality during the first month with a shift towards long-term mortality in surgical patients.
Multiple paper monies in Sweden 1789–1903: substitution or complementarity?
Authors: Engdahl Torbjörn , Ögren Anders 
Published: April 2008

AbstractComplementarity of money means that two or more kinds of monies together fulfil the demands of the users better than they would without the existence of the other(s). In this article we study complementarity between paper monies in Sweden. We address four questions: 1. What was used as money at a macro-level (money supply) and at a micro-level (monetary remittances)? 2. What was the relative value of different monies in parallel circulation? 3. Were there seasonal variations in use and/or value of these monies? 4. Were there geographical variations in use and value? What we find is that the complementarity helped to solve the problem of providing sufficient liquidity domestically over time and space and thus contributed to the maintenance of a stable value of the currency.
Therapeutic mammotome excisions: radial scars
Authors: Morel J. , Michell M. J. 
Published: April 2008

AbstractBenign radial scars, lesions characterised histologically by a fibroelastic core surrounded by stellate duct proliferation, cannot be differentiated from lesions with associated invasive or non-invasive carcinoma on imaging, and histological sampling is therefore mandatory. There is also extensive evidence of the frequency with which radial scars are associated with malignancy and with other lesions that have an associated risk of malignancy. The traditionally accepted management has been the surgical excision of all suspected radial scars because insufficient tissue was removed by standard biopsy techniques to exclude associated lesions. In more recent series, it has been shown that with extensive tissue sampling of such lesions with core biopsy and modern vacuum-assisted sampling devices, the presence of associated malignancy can be excluded, thus negating the need for surgical excision.