bluuebunny/crossref_metadata_2025 huggingface dataset:
The applicability of dip moveout/azimuth moveout in the presence of caustics
Authors: Malcolm Alison E. , de Hoop Maarten V. , Rousseau Jérôme H. Le
Published: February 2005

Reflection seismic data continuation is the computation of data at source and receiver locations that differ from those in the original data, using whatever data are available. We develop a general theory of data continuation in the presence of caustics and illustrate it with three examples: dip moveout (DMO), azimuth moveout (AMO), and offset continuation. This theory does not require knowledge of the reflector positions. We construct the output data set from the input through the composition of three operators: an imaging operator, a modeling operator, and a restriction operator. This results in a single operator that maps directly from the input data to the desired output data. We use the calculus of Fourier integral operators to develop this theory in the presence of caustics. For both DMO and AMO, we compute impulse responses in a constant-velocity model and in a more complicated model in which caustics arise. This analysis reveals errors that can be introduced by assuming, for example, a model with a constant vertical velocity gradient when the true model is laterally heterogeneous. Data continuation uses as input a subset (common offset, common angle) of the available data, which may introduce artifacts in the continued data. One could suppress these artifacts by stacking over a neighborhood of input data (using a small range of offsets or angles, for example). We test data continuation on synthetic data from a model known to generate imaging artifacts. We show that stacking over input scattering angles suppresses artifacts in the continued data.
Perturbation approach to depth extrapolation
Authors: Mittet Rune
Published: February 2005

The Born-series solution of the Lippmann-Schwinger equation does not necessarily converge properly for depth-extrapolation problems. Even more seriously, the Lippmann-Schwinger equation is not necessarily self-consistent for depth extrapolation, unless it is interpreted correctly. A solution is proposed by using the generalized Lippmann-Schwinger equation that includes boundary value contributions that normally are ignored. A modified version of the Lippmann-Schwinger equation for depth extrapolation is obtained. The corrections to the Born-series expansion for depth extrapolation are demonstrated. The new system has the desired convergence and self-consistency properties. Explicit depth extrapolation is discussed in the context of the Lippmann-Schwinger equation. A partial explanation for why explicit depth extrapolation works reasonably well in laterally inhomogeneous media may be that the contribution from the perturbation term in the Lippmann-Schwinger equation for that problem is small for a wide variety of velocity models.
Multicomponent prestack depth migration using the elastic screen method
Authors: Xie Xiao-Bi , Wu Ru-Shan
Published: February 2005

A 3D multicomponent prestack depth-migration method is presented. An elastic-screen propagator based on one-way wave propagation with a wide-angle correction is used to extrapolate both source and receiver wavefields. The elastic-screen propagator neglects backscattered waves but can handle forward multiple-scattering effects, such as focusing/defocusing, diffraction, interference, and conversions between P- and S-waves. Vector-imaging conditions are used to generate a P-P image and a P-S converted-wave image. The application of the multicomponent elastic propagator and vector-imaging condition preserves more information carried by the elastic waves. It also solves the polarization problem of converted-wave imaging. Partial images from different sources with correct polarizations can be stacked to generate a final image. Numerical examples using 2D synthetic data sets are presented to show the feasibility of this method.
SEG: 75 Years and Going Strong
Authors: Schuster Gerard T.
Published: February 2005

The year 2005 marks the 75th anniversary of the Society of Exploration Geophysicists. Among the many commemorations is a series of special papers in GEOPHYSICS throughout 2005, providing an overview of the journal and how it has advanced the field of exploration geophysics. A motivation for this series is to allow young geophysicists and veterans to temporarily step aside from computer terminals and innumerable meetings to revel in the panoramic view of our shared history of geophysical technology and science that has had such a tremendous impact on the development of modern civilization.
The History, Current Status, and Future of GEOPHYSICS
Authors: Clark Dean
Published: February 2005

As part of the commemoration of the 75th anniversary of the Society of Exploration Geophysicists, SEG Editor Gerard T. Schuster decided to canvass the living former editors regarding the history, current status, and future of the journal GEOPHYSICS. His plan was to solicit e-mail responses to a series of questions and then quickly follow up with a conference call in which respondents could elaborate on their remarks or comment on the answers of their colleagues… or (probably what Schuster really wanted) the electronic overloading of so much geophysical talent would result in a critical mass that would send the discussion into a new and very productive direction.
Intellectual Property
Authors: Walker David A.
Published: February 2005

The Intellectual Property department in each issue of Geophysics provides U.S. patent abstracts, published patent abstracts of U.S. patent applications, and published abstracts filed under the Patent Cooperation Treaty (PCT).
Statins: immunomodulators for autoimmune rheumatic disease?
Authors: Jury E C , Ehrenstein M R
Published: February 2005

Inhibitors of 3-hydroxy-3-methylgluttaryl coenzyme A (HMG-CoA) reductase, or statins, are used extensively to reduced elevated lipid levels and reduce cardiovascular risk. However, accumulated evidence suggests that stains not only act by lowering cholesterol levels, but also exert pleiotropic effects on many essential cellular functions including cell proliferation, differentiation, and survival and participate in the regulation of cell shape and motility. Thus cardiovascular benefit is provided by lowering raised cholesterol levels and by modulation of the inflammatory component of this disease. Such an anti-inflammatory effect may also benefit patients with autoimmune rheumatic disease. This overview assesses the evidence for using statins in patients with rheumatoid arthritis and systemic lupus erythematosus (SLE).
Autologous peripheral blood stem cell transplantation with in vivo T-cell depletion for life threatening refractory systemic lupus erythematosus
Authors: Talaulikar D , Tymms K E , Prosser I , Smith R
Published: February 2005

We report the first Australian application of autologous haemopoietic stem cell transplantation in a 39-year old woman with severe systemic lupus erythematosus (SLE) and multiple life threatening complications, refractory to conventional therapy including intravenous cyclophosphamide. Our transplant technique, although not unique, differs from most published reports, in which an unmanipulated peripheral stem cell graft was used with in vivo lymphocyte depletion using rabbit antithymocyte globulin (ATG). Successful stem cell mobilization was achieved using granulocyte-colony stimulating factor mobilization with methylprednisolone cover, after an initial attempt at mobilization was curtailed by respiratory arrest from upper airway obstruction due to cricoarytenoiditis, requiring tracheostomy. Conditioning regimen for the transplantation was cyclophosphamide 50 mg/kg on days 25to 22 and rabbit ATG 2.2 mg/kg on days 23 and 22. An unmanipulated autograft was infused, with in vivo T-cell depletion achieved through a further dose of ATG given on day +2 postinfusion. The autologous transplant was well tolerated without fever or other serious complication. At 12 months follow-up post-transplantation, there is an objective evidence of near-complete response with SLE disease activity index scores falling from 40 pretransplant to 2. We conclude that HSCT with unmanipulated peripheral stem cell graft and in vivo lymphocyte depletion with ATG is safe and effective therapy for cyclophosphamide refractory SLE.
Hypoparathyroidism in systemic lupus erythematosus
Authors: Nashi E , Banerjee D , Crelinsten G
Published: February 2005

We present the case of a man diagnosed with lupus and hypoparathyroidism. This combined diagnosis has very rarely been reported, which is surprising given the evidence that idiopathic hypoparathyroidism can be due to autoimmunity, the multiplicity of organ systems that lupus can affect and the evidence that other endocrinopathies such as hypothyroidism do occur at increased rates in patients with lupus. Hypoparathyroidism does not always cause overt clinical symptoms but the resultant hypocalcemia be a significant health risk. In addition to presenting the case, we review the relevant literature and offer a discussion.
Theory, targets and therapy in systemic lupus erythematosus
Authors: Vasoo S , Hughes G RV
Published: February 2005

The treatment of systemic lupus erythematosus (SLE) has been refined over the years, with the recognition that a fine balance lies between aggressive and prompt therapy and attendant complications brought upon by immunosuppressive therapy itself. However, there has been limited change to the repertoire of drugs available to treat this challenging disease. The current standard therapy for severe manifestations of SLE includes the use of high-dose corticosteroids and cytotoxic agents such as cyclophosphamide (CYC), which have been associated with an increased risk of serious and opportunistic infections. The need for safer, more targeted therapies has been recognized and now, with the exponential increase in the understanding of immunopathogenic mechanisms in SLE, the way has been paved for the development of biologic or targeted therapies in SLE. Although the potential immunosuppression, long-term safety issues and cost-effectiveness remain unclear. These targeted therapies may range from small molecules that specifically inhibit inflammatory processes at an intracellular, cell-cell or cell-matrix level to monoclonal antibodies, soluble receptors or natural antagonists that interfere with cytokine function, cellular activation and inflammatory gene transcription.
A unified web-based Query and Notification System (QNS) for subject management, adverse events, regulatory, and IRB components of clinical trials
Authors: Mitchell Rick , Shah Maitri , Ahmad Sushma , Rogers Audrey Smith , Ellenberg Jonas H ,   Adolescent Medicine Trials Network for HIV/AIDS Interventions
Published: February 2005

Even after intensive review, interpretative questions, ambiguities, contradictions, or errors, will arise once the protocol is scrutinized by site IRBs and implemented at sites. This will occur despite preparation and implementation of site protocol training, and provision of well crafted case report forms for the reporting of clinical and laboratory evaluations and adverse events. Since many staff are involved in each protocol, site investigators or study coordinators might direct protocol queries, participant management, or IRB queries to different network participants, resulting in inconsistent responses. It is important to establish a response mechanism that ensures consistent responses and their systematic documentation. For reporting of adverse events, and the submission of or documentation of completion of regulatory requirements, an easily accessible and structured communications system is also required. This paper describes the development and implementation of a user-friendly web-based query and notification system (QNS) for subject management, adverse events, regulatory, and IRB components. This system was created in the Adolescent Trials Network for HIV/AIDS Interventions (ATN), using existing web based tools with minor modifications and minimal cost. The query and notification system is interactive and allows for free flow of information among the site coordinators and both the protocol teams and the regulatory group. The process of the system is transparent to users at the sites, although its use and maintenance is controlled by Data Operations Center staff, to assure that ATN requirements for review and approval are met. This results in consistency of and timeliness of responses to queries, timeliness and accuracy of adverse event reporting and the ability for the data operations center regulatory staff to provide notification of pending or delinquent regulatory submissions.
The ethics of confidentiality in teaching and research: Invited commentary on… re-evaluating confidentiality
Authors: Tyrer Peter
Published: February 2005

Draper & Rogers (2005, this issue) have put an important subject under the ethical microscope. They have demonstrated that the current, fairly simple, rules applying to the publication of case studies and dissemination of patient information in teaching are inadequate and need revision. This is particularly important because such forms of communication are likely to increase in the future. Many journals, including the British Journal of Psychiatry, generally frown upon case studies as representing little value to science: case studies unnecessarily focus on the particular; their message is only valuable when it is general. However, they aren't going to go away because their educational value is obvious, as anyone who looks at the handling of almost any scientific subject in the mass media will testify. Experts can pontificate on hypotheses, proportions, means and significance to little effect and the real message comes home from a sufferer or successfully treated patient who adds human flesh to a dry factual skeleton. This need to particularise is necessary in all parts of teaching.
Service innovations: The role of a consultant in old age psychiatry
Authors: Lawley David , Bestley John , Talbot Andy , Hostick Gary
Published: February 2005

There is increased recognition that the role and function of a consultant psychiatrist is ill-defined and associated with excessive workloads, low job satisfaction, high levels of stress and high rates of premature retirement (Kennedy & Griffiths, 2001). This has led to an examination and debate about how consultants in general psychiatry could adapt models of working to address these difficulties, and also face the agenda of change facing the NHS as a whole and the mental health services in particular (Kennedy & Griffiths, 2001; De Silva & Sutcliffe, 2003). These challenges are not, of course, unique to general psychiatry, but as yet, there has been little debate about how consultants in other specialities, including old age psychiatry, could begin to try and address these difficulties. This article aims to stimulate debate, by describing an adapted model of working adopted by two consultants in old age psychiatry within the Hull and East Riding Community Health NHS Trust.
Information Sources for Noun Learning
Authors: Kako Edward
Published: February 2005

Why are some words easier to learn than others? And what enables the eventual learning of the more difficult words? These questions were addressed for nouns using a paradigm in which adults were exposed to naturalistic maternal input that was manipulated to simulate access to several different information sources, both alone and in combination: observation of the extralinguistic contexts in which the target word was used, the words that co‐occurred with the target word, and the target word's syntactic context. Words that were not accurately identified from observation alone were both abstract (e.g., music) and concrete (e.g., tail). Whether a noun could be learned from observation depended on whether it labeled a basic‐level object category (BLOC). However, the difference between BLOC labels and non‐BLOC labels was eliminated when observation was supplemented with linguistic context. Thus, although BLOC labels can be learned from observation alone, non‐BLOC labels require richer linguistic context. These findings support a model of vocabulary growth in which an important role is played by changes in the information to which learners have access.
A Memory‐Based Theory of Verbal Cognition
Authors: Dennis Simon
Published: February 2005

The syntagmatic paradigmatic model is a distributed, memory‐based account of verbal processing. Built on a Bayesian interpretation of string edit theory, it characterizes the control of verbal cognition as the retrieval of sets of syntagmatic and paradigmatic constraints from sequential and relational long‐term memory and the resolution of these constraints in working memory. Lexical information is extracted directly from text using a version of the expectation maximization algorithm. In this article, the model is described and then illustrated on a number of phenomena, including sentence processing, semantic categorization and rating, short‐term serial recall, and analogical and logical inference. Subsequently, the model is used to answer questions about a corpus of tennis news articles taken from the Internet. The model's success demonstrates that it is possible to extract propositional information from naturally occurring text without employing a grammar, defining a set of heuristics, or specifying a priori a set of semantic roles.
Experimental studies on the combustion characteristics and performance of a naturally aspirated, direct injection engine fuelled with a liquid petroleum gas/diesel blend
Authors: Donghui Qi , Longbao Zhou , Shenghua Liu
Published: February 2005

This paper studies the combustion characteristics and performances of a LPG/diesel blend-fuel engine; the influences of mixing ratio of LPG in diesel on the ignition timing, in-cylinder pressure, heat-release rate, specific fuel consumption, power output, and exhaust emissions have been identified. The results indicate that the ignition delay of blend fuel was obviously longer than that of diesel and the higher the mixing ratio of LPG in diesel, the longer the ignition delay. When the mixing ratio of LPG in diesel was 10 per cent, the peak in-cylinder gas pressure and the peak rate of pressure rise were slightly higher than those of diesel, and the corresponding crank angles at which the peak values occurred were almost the same as those of diesel. When the mixing ratio was 30 per cent, the peak in-cylinder pressure and the peak rate of pressure rise were lower than those of diesel, and the corresponding crank angles were retarded. With the increasing of mixing ratio of LPG in diesel, the peak rate of heat release increased and the corresponding crank angles were retarded. The equivalent specific fuel consumption of L10 was the same as that of diesel, but that of L30 was slight higher. The power output of the diesel engine was higher than those of L10 and L30 at speed characteristic of full load, especially at high engine speed. With the increasing of mixing ratio, the smoke emissions and NOx emissions were greatly reduced, and CO emissions decreased too, but HC emissions slightly increased.
Influence of braking force in low-speed vehicle collisions
Authors: Mastandrea M , Vangi D
Published: February 2005

The aim of this research is to find out the influence of braking force on the impact dynamics in low-speed rear-end collisions. The method used to simulate the crash is a step-by-step impulsive model including tyre friction and the rolling resistance effect. The simulation allows a separate analysis of the compression and restitution phases. The first is based upon experimental data of the crash test between the vehicles, the latter leads to two different choices of reconstruction, considering the bumper rebound or neglecting it. The coefficient of restitution is calculated by the force reached at compression ending, thus including the influence of external forces (as friction). The results show a great accuracy and matching with experimental data. The main changes in the impact dynamics due to the rise in braking force are the enlargement of the crush with a delay of the restitution start and a lowering of the coefficient of restitution, the increase of the impact duration and the decrease of the velocities at the collision end. These effects depend on the closing velocity and are more marked at low speed. This study therefore demonstrates that the braking force is not negligible in a good reconstruction of impact dynamics at low speed.
A study on an electronically controlled liquefied petroleum gas-diesel dual-fuel automobile
Authors: Zhang Chunhua , Bian Yaozhang , Si Lizeng , Liao Junzhi , Odbileg N
Published: February 2005

In this paper, the control scheme of a liquefied petroleum gas (LPG)-diesel dual-fuel engine with electronic control is illustrated, the external characteristics and load characteristics of the LPG-diesel dual-fuel engine and the diesel engine are compared and analysed, and the results of automobile road tests are also given. The experimental results show that, compared with diesel, the output performance of dual fuel is not reduced, while smoke emission of dual fuel is significantly reduced, NOx emission of dual fuel is hardly changed, but HC emission and CO emission of dual fuel are increased and fuel consumption of dual fuel is reduced.
The influence of seat back rake on ligament loadings in rear-end impact
Authors: Golinski W Z , Gentle R
Published: February 2005

A biomechanical finite element (FE) model of the 50th percentile male human cervical spine, capable of predicting ligament loadings in whiplash scenarios, has been developed and previously reported. The study reported here analyses the influence of seat back rake on ligament injury in two scenarios: firstly, the in position, where the car occupant is looking forward and the head remains in the sagittal plane, and, secondly, the out of position, where the car occupant is initially looking slightly to one side. In both cases the results show an increase in ligament loading with a decrease of seat back rotational stiffness, substantiating the need for dynamic seat testing. Moreover, comparing individual ligament loading data shows that the initial head rotation scenario is more damaging to the cervical spine than the sagittal plane scenario, confirming a published hypothesis.
Research and development of an advanced combustion system for the direct injection diesel engine
Authors: Su W H , Lin T J , Zhao H , Pei Y Q
Published: February 2005

In order to obtain a simultaneous reduction in both NOx and particulate emissions from a direct injection (DI) diesel engine, an advanced combustion system has been researched and developed in the authors' laboratory. The new combustion system comprises homogeneous charge compression ignition (HCCI) combustion at low load by early and multiple injections, combined HCCI, and lean diffusion burning at medium and higher load conditions by means of a novel combustion chamber design and multiple injections. In this paper, the research and development of the enhanced mixing by means of a raised round object (referred to in this paper as BUMP) and its application to a diesel combustion chamber design is described. Then the experimental results from a DI diesel engine equipped with a multiple injection common rail (CR) fuel injection system and the new combustion chamber design will be presented and discussed.

Engine testing has shown that the BUMP combustion chamber was very effective in reducing both NOx and smoke emissions. HCCI combustion by means of multiple injections leads to extremely low NOx emissions under low load operations. At medium and higher load operation conditions, quasi HCCI combustion combined with the BUMP combustion chamber could signficantly reduce NOx emissions without sacrificing particulate emission and fuel consumption.
Selective Extraction of Endohedral Metallofullerenes Using a Mixed Solvent of Triethylamine and Acetone
Authors: Kodama Takeshi , Higashi Korenari , Ichikawa Takafumi , Suzuki Shinzo , Nishikawa Hiroyuki , Ikemoto Isao , Kikuchi Koichi , Achiba Yohji
Published: February 2005

We have developed a single-step method for selectively extracting endohedral metallofullerenes. In this new method, a mixed solvent of triethylamine and acetone is used to extract endohedral metallofullerenes from raw soot. The efficiency of extraction was investigated by extracting Ce-containing metallofullerenes, Ce@C82 and Ce2@C80, from raw soot obtained by an arc discharge technique. The resultant extract contained little or no empty fullerenes such as C60 or C70, that is, the Ce-metallofullerenes were selectively extracted.
Synthesis of Box-shaped Pentaporphyrin with Cobalt(II) Porphyrin in the Center; Reversible O2 Binding in the Box
Authors: Uruma Keirei , Tsuge Kiyoshi , Sasaki Yoichi , Imamura Taira
Published: February 2005

Aiming at construction of robust molecular architectures having an active center surrounded by stable walls, a box-shaped cobalt(II)–rhodium(III) pentaporphyrin [Co(tpyp)][Rh(tpp)Cl]4 (2) (tpyp = 5,10,15,20-tetrapyridylporphyrinato dianion, tpp = 5,10,15,20-tetraphenylporphyrinato dianion) was newly synthesized via coordination bonds. The cobalt(II) center of the complex 2 reacts reversibly with O2 to give a corresponding dioxygen complex of [Co(tpyp)(py)(O2)][Rh(tpp)Cl]4 (2-(py)(O2)) at low temperatures in dichloromethane-containing pyridine.
Reaction of (4-Nitorophenyl)nitrene with Molecular Oxygen in Low-temperature Matrices: First IR Detection and Photochemistry of Aryl Nitroso Oxide
Authors: Inui Hiroshi , Irisawa Masatoshi , Oishi Shigero
Published: February 2005

The thermal reaction of (4-nitrophenyl)nitrene with oxygen in low-temperature matrices produced a new molecular species, which was identified as 4-nitrophenylnitroso oxide on the basis of its IR spectrum in combination with isotopic labeling with 18O2 and vibration analyses by the DFT method. This is the first report for the infrared detection of an aryl nitroso oxide. We could monitor also the wavelength-dependent N–O and O–O bond cleavage of the nitroso oxide.
Stilbene-extended Trithienylmethanophanes: A Novel C3-Symmetric Cage Molecule Capable of Accommodating an Organic Molecule As Well As Three Silver(I) Ions
Authors: Kurata Hiroyuki , Haruki Kenji , Oda Masaji
Published: February 2005

A combination of the Suzuki and the McMurry coupling on tris(5-bromo-2-thienyl)methanes leads to the title compounds which accommodate one n-hexane molecule or three silver(I) ions in the cavity.
Degradation of p-Chlorophenol by γ-Radiolysis: Radiolytic Intermediates and Theoretical Calculations
Authors: Liu Shao-Yang , Chen You-Peng , Yu Han-Qing , Li Qian-Rong
Published: February 2005

Radiolysis of p-chlorophenol (p-CP) was investigated through experiments and theoretical calculations. Its radiolytic intermediate products, i.e., phenol, hydroquinone, 4-chlororesorcinol, and 4-chloropyrocatechol, were identified using their mass spectra through a GC/MS system. Three transition states and a prereaction complex of the reaction between hydroxyl radical and p-CP were found from the density functional theory (DFT) study. Both the experimental and calculation results demonstrate that the main p-CP degradation pathway was the formation of 4-chloropyrocatechol.
Synthesis of Kaolinite with a High Level of Fe3+ for Al Substitution
Authors: Iriarte Iñaki , Petit Sabine , Javier Huertas F. , Fiore Saverio , Grauby Olivier , Decarreau Alain , Linares José
Published: February 2005

Fe-rich kaolinites were synthesized at 225°C in distilled water from gels with different Fe/Al ratios (0.15, 0.25, 0.35) and with Si/(Al + Fe) = 2. X-ray diffraction patterns of the reaction products showed that kaolinite was the only long-range crystalline phase synthesized. Analytical electron microscopy analyses of individual particles and Fourier transform infrared spectra indicated that Fe3+ was isomorphously incorporated into the kaolinite octahedral sheet and that tetrahedral substitution did not occur. The Fe content hosted in the synthetic kaolinites was similar to that incorporated into its corresponding starting gel. The highest Fe content in the particles reached 30 mol.% of the octahedral occupancy. Increases in the b parameter are proportional to increases in Fe for Al substitution. The extent of isomorphic substitution of Al by Fe is the highest ever reported for both natural and synthetic samples. At the nano-scale, there is no evidence of discontinuity in the solid-solution between the Si2Al2O7 and Si2Al1.4Fe0.6O7 end-members, such as short-range disorder or clustering of Fe and Al in domains.
Synthesis of a Mg2+-Al3+-SO42−-Hydrotalcite-Type Compound from the acid Wastewaters of the Aluminum-Anodizing Industry
Authors: Álvarez-Ayuso E. , Nugteren H. W.
Published: February 2005

The synthesis of a Mg2+-Al3+-SO2−4-hydrotalcite-type compound from the acid wastewaters of the aluminum-anodizing industry has been studied as a possible means of recovering the unused Al resource materials as a useful mineral. The synthesis has been carried out from wastewaters of different concentrations (from 6.7 g Al/L to 134 mg Al/L) using the method of precipitation at constant pH, proving that all of them are suitable for such a process. The mineral was characterized using X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, differential thermal analysis and chemical analysis, all of which indicated characteristics typical of the desired compound. Almost 100% of the Al initially present in the wastewater solutions is recovered in the form of the Mg2+-Al3+-SO42−-hydrotalcite-type compound.
Substitution of Fe3+ for Al3+ Cations in Layered Double Hydroxide [LiAl2(OH)6]2CO3-nH2O
Authors: Kuśtrowski Piotr , Węgrzyn Agnieszka , Rafalska-Łasocha Alicja , Pattek-Janczyk Agnieszka , Dziembaj Roman
Published: February 2005

Synthesis of the Li-Al-Fe layered double hydroxides was performed by the coprecipitation method at constant pH (11.0±0.2) and temperature (40±2°C). Structural features of the as-synthesized samples were investigated by X-ray diffraction (XRD), infrared (IR) spectroscopy, scanning electron microscopy and Mössbauer spectroscopy. The samples consisted of well crystallized [LiFexAl2-x(OH)6]2CO3·nH2O phases with strict ordering of M+ and M3+ cations in the sheets. However, only a proportion of Al3+ could be substituted by Fe3+ ions. The excess Fe3+ cations formed a separate ferrihydrite phase. Incorporation of Fe into the hydrotalcite-like structure resulted in an increase in the a lattice parameter determined by XRD. In addition, a shift of IR absorption bands, ascribed to the stretching vibrations of interlayer CO32− anions as well as the transitional motions of oxygen in the layers, to lower frequencies was observed. The presence of Fe3+ in the octahedral sheets caused a splitting of the band assigned to the stretching vibrations of the layer OH groups. Mössbauer experiments revealed that Fe exists in the synthesized samples in two different chemical environments. A proportion of the Fe3+ cations is incorporated as isolated ions in the [LiFexAl2-x(OH)6]2CO3.nH2O crystal structure. However, Fe3+ ions forming the ferrihydrite phase are dominant in the Fe-rich materials.
Microscopy Studies of the Palygorskite-to-Smectite Transformation
Authors: Krekeler Mark P. S. , Hammerly Eric , Rakovan John , Guggenheim Stephen
Published: February 2005

The transformation process between palygorskite and smectite was studied by examining the morphological and structural relationships between these two minerals in an assemblage from the Meigs Member of the Hawthorne Formation, southern Georgia. Studied samples were related to an alteration horizon with a tan clay unit above and a blue clay unit below. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) were used to study the mechanism of transformation.

From AFM data, both clay units contain euhedral palygorskite fibers. Many fibers are found as parallel intergrowths joined along the [010] direction to form ‘raft-like’ bundles. Degraded fibers, which are common in the tan clay, have a distinctly segmented morphology, suggesting a dissolution texture. Many of the altered palygorskite fibers in the tan clay exhibit an oriented overgrowth of another mineral phase, presumably smectite, displaying a platy morphology. This latter mineral forms along the length of the palygorskite crystals with an interface parallel to {010} of the palygorskite. The resulting grain structures have an elongate ‘wing-like’ morphology.

Imaging by TEM of tan clay material shows smectite lattice-fringe lines intergrown with 2:1 layer ribbon modules (polysomes) of the palygorskite. These features indicate an epitaxial overgrowth of smectite on palygorskite and illustrate the structural relationship between platy overgrowths on fibers observed in AFM data. The epitaxial relationship is described as {010} [001] palygorskite ‖ {010} [001] smectite.

Energy dispersive spectroscopy indicates that the smectite is ferrian montmorillonite. Polysomes of palygorskite fibers involved in these textures commonly vary and polysome widths are consistent with double tetrahedral chains (10.4 Å), triple tetrahedral chains (14.8 Å), quadruple tetrahedral chains (21.7 Å) and quintuple tetrahedral chains (24.5 Å).

The transformation of palygorskite to smectite and the resulting intergrowths will cause variations in bulk physical properties of palygorskite-rich clays. The observation of this transformation in natural samples suggests that this transformation mechanism may be responsible for the lower abundance of palygorskite in Mesozoic and older sediments.
Titanite Low-Temperature Alteration and Ti Mobility
Authors: Tilley David B. , Eggleton Richard A.
Published: February 2005

A pseudomorphous aggregate after titanite composed of smectite, anatase and residual titanite of composition (Ca0.98,Mn0.02)(Ti0.65,Al0.35)[SiO4](O0.65,OH0.35), from a depth of 450 m in the Broken Hill South Mine, New South Wales, Australia, was investigated by electron microscopy and microanalysis to characterize the alteration products and the mobility of Ti. Examination of the pseudomorph showed randomly oriented anatase crystals dispersed throughout a matrix of beidellite, with 9% porosity. Around the periphery and along the (110) cleavage plane of titanite, alteration was most developed. The range of Ti mobility was found to be limited to ~500 nm, and the ratio between the average diameter of anatase crystals and the average distance between them is ≈1.3. This ratio is consistent with an alteration process in which Ti is conserved and the anatase crystals grow from the Ti available immediately around them. It is unlikely that Ti migrated beyond the titanite pseudomorph.
Death is That Man Taking Names
Authors: Momberger Karla
Published: February 2005

Death is That Man Taking Names Robert A. Burt (Berkeley: University of California Press; New York: Milbank Memorial Fund, 2002)
Comparison of Push Nets and Tow Nets for Sampling Larval Fish with Implications for Assessing Littoral Habitat Utilization
Authors: Claramunt Randall M. , Shoup Daniel E. , Wahl David H.
Published: February 2005

Understanding sampling effectiveness is critical to gear selection and the determination of larval fish dynamics. We evaluated bow-mounted push nets for collecting larval fish across reservoirs and habitats and compared them with traditional tow nets. By means of a pushed 0.5-m-diameter conical net and towed 0.5-m-diameter and 0.75-m-diameter conical nets, ichthyoplankton samples were taken during daylight hours from May to July on 21 reservoirs that varied in morphological and environmental characteristics. The push net had higher catches than the same-diameter tow net. However, the push net was not as efficient as the larger-sized tow net in July, when larvae are larger. For pelagic habitats, bow-mounted push nets or large tow nets will sample the larval fish community more efficiently than traditional 0.5-m-diameter conical tow nets. We also assessed push nets for sampling nearshore littoral habitats (<1.0 m in depth). Across reservoirs the littoral areas had much higher catch rates than did the offshore pelagic zone; estimates of peak larval fish densities were four times as high in the littoral zone. Deriving estimates of larval fish abundance from pelagic habitats only will probably lead to underestimation of total larval fish densities. The versatility of the push net in sampling littoral habitats is an important consideration when designing surveys to estimate larval fish communities. Bow-mounted push nets can be used to effectively sample both pelagic and littoral larval fish communities, whereas traditional tow nets are only suited for pelagic habitats.
Relationships between Recapture Rates from Different Gears for Estimating Walleye Abundance in Northern Wisconsin Lakes
Authors: Rogers Mark W. , Hansen Michael J. , Beard T. Douglas
Published: February 2005

Maximizing sampling efficiency and reducing sampling costs are desirable goals for fisheries management agencies. Expensive and labor-intensive methods (such as mark–recapture) are commonly used to estimate the population abundance of walleye Sander vitreus, but more efficient methods may be available. We compared recapture rates from surveys and harvests to evaluate the efficiency of currently used recapture gears and the potential for using gears that require less effort. To evaluate the usefulness of walleye harvest as mark–recapture samples, we used errors-in-variables models to determine whether recapture rates differed between fyke-netting and spearing, electrofishing and spearing, and electrofishing and angling. We found no significant differences between fyke-netting and adult walleye electrofishing recapture rates or between spearing and adult walleye electrofishing recapture rates. In contrast, we found that recapture rates from angling and electrofishing differed significantly in lakes with and without minimum length limits. We concluded that the lack of significant differences between the slopes of some harvest and survey recapture rates may allow the use of harvest recapture rates to estimate walleye abundance, but the biases associated with each gear should be considered. We also concluded that more attention should be given to understanding the biases of recapture gears.
Distribution and Abundance of Black Bass in Skiatook Lake, Oklahoma, after Introduction of Smallmouth Bass and a Liberalized Harvest Regulation on Spotted Bass
Authors: Long James M. , Fisher William L.
Published: February 2005

We conducted a 3-year study to examine the trends in abundance and distribution of three sympatric black bass species (Micropterus) in an Oklahoma reservoir after implementation of a differential harvest regulation to reduce the abundance of spotted bass M. punctulatus and after stocking nonnative smallmouth bass M. dolomieu. Largemouth bass M. salmoides were stocked in Skiatook Lake, Oklahoma, immediately after its creation in 1984 to supplement the existing population in the watershed. Nonnative smallmouth bass were stocked in 1990, and their abundance and distribution have increased ever since. Native spotted bass, which have less fishery value than the other two black bass species, increased fivefold in abundance in 1994, became the predominant black bass species by at least 1996, and appeared to displace largemouth bass from many habitats. From boat-mounted electrofishing sampling conducted in April and May 1997–1999, we found that spotted bass abundance (proportion and catch per hour) had decreased while smallmouth bass abundance and distribution within the reservoir steadily increased. Largemouth bass abundance did not change among years. Throughout our study period, spotted bass was always the most abundant black bass species where differences in abundance were found. Our results suggest that the continually expanding smallmouth bass population is displacing spotted bass from many of their formerly used habitats, much like spotted bass had displaced largemouth bass by 1996.
Evaluating the Effectiveness of Instream Habitat Structures for Overwintering Stream Salmonids: A Test of Underwater Video
Authors: Carlson Leah D. , Quinn Michael S.
Published: February 2005

Instream habitat structures are often employed by fisheries managers to enhance habitat quality. The effectiveness of instream habitat structures, however, is hindered by a lack of critical and systematic assessment of their success, especially in winter conditions. This study tested the use of underwater video as a method to evaluate the use of instream habitat structures (V-weirs) by overwintering salmonids in the Crowsnest River of southwestern Alberta, Canada. The use of readily available and relatively inexpensive video equipment was shown to be effective in documenting salmonid use of winter habitat both under the ice and in open water. This technique may be particularly appropriate in areas where sampling mortality is a concern and where other methods are impractical or dangerous (e.g., small, ice-covered streams or rivers).
Sand Seals in Coho Salmon Redds: Do They Improve Egg Survival?
Authors: Meyer Carolyn B. , Sparkman Michael D. , Klatte Bernard A.
Published: February 2005

We investigated whether sand seals form in the upper egg pocket of salmonid redds and improve egg survival in a sediment-impacted coastal stream in northern California. Sand seals can potentially reduce infiltration of detrimental finer sand and silt into the lower egg pocket. We predicted sand seals would form when the redds were exposed to streamflows high enough to entrain coarse sand and form seals. Using artificial redds of coho salmon Oncorhynchus kisutch, we conducted sediment analyses of the upper and lower egg pockets and found that protective sand seals formed in redds when discharge was two or more times the flow that entrains the median particle size of the streambed. When the coarse sand in the upper egg pocket was incorporated into a two-stage model that predicted survival to hatching and emergence, it greatly improved predictions in years with higher flows in both natural and artificial redds. However, the sand seals provided little protection when suspended sediment flux was high from logging or road construction. We built the model used for these predictions with data from artificial redds and applied it to natural redds during 6 years of different flow regimes. Predictor variables included cumulative flow above the entrainment flow, peak discharge, coarse sand in the upper egg pocket, fine sediment in riffle gravel, coarse sand in the upper and entire egg pocket, suspended sediment flux, and presence of predaceous worms. The model explained 67% of the variance in egg survival to emergence in coho salmon natural redds. We suggest that managers consider the complex interactions of streamflow, sediment transport, formation of sand seals, and fine-sediment infiltration when estimating salmonid reproductive success in sediment-impacted streams.
Assessing Age-0 Year-Class Strength of Fast-Growing Largemouth Bass in a Tropical Reservoir
Authors: Ozen Ozcan , Noble Richard L.
Published: February 2005

Age-0 largemouth bass Micropterus salmoides were collected every 3 weeks from 1992 to 1994, every 6 weeks from 1995 to 1998, and about every 15 weeks from 1999 to 2000 by means of a handheld electrofisher in Lucchetti Reservoir, Puerto Rico. An extended hatching period (January to June) and a high (0.63–1.50-mm/d) juvenile daily growth rate required high sampling effort because age-0 largemouth bass recruited to the sampling gear between February and September. To assess whether the handheld electrofisher catch per unit effort (CPUE; fish/h) of age-0 largemouth bass was a reliable estimator of relative year-class abundance, we regressed the age-1 largemouth bass CPUE obtained with a conventional boat electrofisher between 1994 and 2001 on the CPUE of age-0 (<150-mm) fish from the previous years. Simple linear regression analyses indicated that as much as 90% (P < 0.01; N = 7) of the variation in age-1 CPUE could be explained by age-0 mean CPUE. Early variation of year-class abundance of largemouth bass can be detected efficiently with the handheld electrofisher, thereby allowing early evaluation of management options.
Influence of Circle Hook Size on Hooking Efficiency, Injury, and Size Selectivity of Bluegill with Comments on Circle Hook Conservation Benefits in Recreational Fisheries
Authors: Cooke Steven J. , Barthel Brandon L. , Suski Cory D. , Siepker Michael J. , Philipp David P.
Published: February 2005

Hook size is an important consideration in the use of circle hooks as a conservation tool for minimizing the injury and mortality of marine fishes, but little is known about the role of hook size in the performance of hooks in recreational freshwater fisheries. In this study, we angled 100 bluegills Lepomis macrochirus on each of five different-sized circle hooks (1/0, 2, 6, 10, and 14). The largest hook size (1/0) had low hooking and capture efficiency but selected larger individuals. The smallest hook size also had low hooking efficiency and resulted in the selection of smaller individuals. Intermediate hook sizes captured fish of intermediate size. Jaw hooking rates generally increased with decreasing hook size, whereas roof hooking rates decreased. Gullet hooking was restricted to the three smallest hook sizes. Relative hooking depth and incidences of bleeding were uniformly low for all hook sizes. Similarly, the fish were generally easy to remove from the hook irrespective of hook size. Our mortality projections revealed no trends associated with hook size, our overall mortality rate being less than 1%. This study suggests that circle hooks function most effectively when the entire hook can fit in the mouth of the fish and when the shank-to-point distance is large enough to permit jaw hooking. Size selectivity for larger individuals can be achieved by using larger hook sizes. However, large circle hooks will also catch smaller fish that will be more likely to be hooked in injurious anatomical locations. Therefore, we recommend the use of intermediate-sized hooks for maximizing hook performance in terms of size selectivity, efficiency, and conservation.
Re‐envisioning Reading and Writing Through Combined‐Text Picture Books
Authors: Dean Deborah , Grierson Sirpa
Published: February 2005

Combined‐text picture books unite multiple genres, providing nuanced information on a single topic from the unique lens of each genre. By providing guided practice in reading and writing a combined‐text picture book, teachers can help students develop sensitivity to different types of texts, to what they do and how they do it. Such sensitivity can give students a foundation for selecting appropriate strategies for reading and writing effectively in a wider variety of genres. This article describes the process of explicit instruction, discussion, and guided practice with one such text,One Leaf Rides the Wind, that helped one class of seventh‐grade students develop as strategic readers and writers when they created a class version of a combined‐text picture book.