bluuebunny/crossref_metadata_2025 huggingface dataset:
On the Origin of Quasar Absorption Lines
Authors: John N Bahcall
Published: January 2007

Many predictions have been made on the basis of the cosmological hypothesis for the origin of quasar absorption liens. The observational evidence relating to these predictions is summarized. It appears likely that many of the observed absorption lines originate in material that is separated from the emitting quasar by cosmological distances. Two special problems are briefly discussed: the interpretation of redshift splittings and the origin of absorption redshifts larger than their associated emission redshifts.
Extended and Compact Extragalactic Radio Sources: Interpretation and Theory
Authors: Roger D Blandford  , Martin J Rees
Published: January 2007

The interpretation of strong double radio sources in terms of the "beam" model is reviewed. Implications of this model for source evolution and the nature of radio trails are briefly discussed. A final section is concerned with deductions about the properties of compact and variable components in quasars and galactic nuclei.
Future Prospects of Infrared Observations of Active Nuclei
Authors: G Neugebauer
Published: January 2007

Future developments in infrared observations are briefly discussed. The prospects for large advances in ground-based broad-band observations probably lie in increased availability of dedicated telescopes and observing time. Several specific areas of potential advancement are described. The plans for the utilization of space for infrared astronomy call for an unbiased all-sky survey in the wavelengths 8-120 μm followed by complementary missions using a cooled moderate sized telescope and a large uncooled telescope.
The CTIO Surveys for Large Redshift Quasars
Authors: Patrick S Osmer
Published: January 2007

Lyman α emission in large redshift quasars is readily detectable on slitless spectrograms taken with an objective prism on the Curtis Schmidt and with a transmission grating-prism combination on the 4 m telescope. This provides a new survey method, independent of color, for finding radio-quiet quasars in large numbers. Surveys by Smith with the Curtis Schmidt and Hoag and Smith with the 4 m telescope, have produced more than 200 candidates with 1.5 < z < 3.5 and 16 < m < 21.

Spectroscopic observations with the CTIO SIT vidicon system have been carried out for more than 50 of the candidates, with the result that the basic properties of the surveys are known. To date three 16th magnitude quasars with z ∼ 2.2 and six quasars with 3.0 < z < 3.25 have been found. One of the most important uses of the surveys will be the determination of the surface and space densities of large redshift quasars. A preliminary analysis of the data indicates that the space density of quasars is at least constant, if not increasing, over the interval 1.9 < z < 3.25. However, the Hoag-Smith sample has only one candidate with z > 3.2.
Remark on Activity in Nuclei of Spiral Galaxies Different from that in Seyfert Galaxies
Authors: J H Oort
Published: January 2007

Attention is drawn to some types of large-scale eruptive phenomena which differ from those observed around the nuclei of Seyfert galaxies.
Trapping of Non-Resonance Radiation in Atoms and its Influence on Measured Lifetimes of the 4p and 5p Levels in Ar I
Authors: Peter Erman  , Sven Huldt
Published: January 2007

Lifetimes of 17 levels of the 3p54pand 3p55pconfigurations in Ar I have been measured using the High Frequency Deflection technique at target pressures in the range 0.04-10 mtorr. An anomalous pressure dependence is found which indicates that the studied 4p, 5p→ 4s(non-resonance) transitions are subjected to trapping effects which occur because of exceptionally long lifetimes of the 4slevels due to either 4s→ 3presonance trapping (4s, J= 1) or metastability (4s, J= 0, 2). A theoretical fit to the observed pressure dependence based upon this process is given as well as corrected zero pressure lifetimes which in several cases are considerably shorter than earlier published values.
Radiative Lifetimes for Selected Astrophysically Important Resonance Transitions of F I, Si II, S I, II, III, P II, and CO
Authors: Wm Hayden Smith
Published: January 2007

Radiative lifetimes for selected upper levels for transitions of F I, Si II, S I, II, and III, P II, and the CO molecule, lying between 950 Å and 1350 Å have been measured with the phase shift method. These species have been observed or sought via these transitions with the Copernicus satellite. The measured laboratory lifetimes ranged from 0.5 to 26 ns. Comparison is made with previous measurements where possible and the results of the Copernicus satellite in determining interstellar abundances.
A Perturbation Expansion for the Nonlinear Schrödinger Equation with Application to the Influence of Nonlinear Landau Damping
Authors: J Weiland  , Y H Ichikawa  , H Wilhelmsson
Published: January 2007

The Bogoliubov-Mitropolsky perturbation method has been applied to the study of a perturbation on soliton solutions to the nonlinear Schrödinger equation. The results are compared to those of Karpman and Maslov using the inverse scattering method to those by Ott and Sudan on the KdV equation and to a recent paper by Pereira and Stenflo.
The Electromagnetic Field near a Metal Surface in the Semi-classical Infinite Barrier Model
Authors: P Apell
Published: January 2007

The electromagnetic field has been calculated in the semi-classical infinite barrier model (SCIB). Since the conductivity tensor is discontinuous at the surface, the field component perpendicular to the surface is found to be discontinuous. In the surface region the field is modified due to single-particle excitations. This contribution to the vector potential is analyzed carefully and numerical results, as for the vector potential, is given. For certain angles of incidence and frequencies the transmitted wave propagates nearly parallel to the surface and the usefulness of the SCIB-model is questioned since it does not describe the detailed surface properties properly. Expressions and numerical results for the distribution of absorbed energy are given and a discussion of the local absorption of energy sometimes becoming negative.
Theoretical Investigation of Transition Probabilities for 2s22p2-2s2p3-2p4 of Ca XV, Fe XXI
Authors: P O Bogdanovich  , G V Merkelis  , Z B Rudzikas  , S D Sadziuviene  , U I Safronova
Published: January 2007

Two different methods have been used for a theoretical investigation of the energy spectra as well as transition probabilities of 2s
22p
2-2s2p
3-2p
4 in the case of Ca XV and Fe XXI: the non-relativistic Hartree-Fock method with relativistic corrections in the Breit approximation and the first two orders of a perturbation expansion in powers of 1/Z. Calculations are made in intermediate coupling using LS basis functions. Eigen-functions and eigenvalues of the Hamiltonian considered as well as wave-lengths and transition probabilities are presented in tables. The data obtained show that both methods lead to results which are in good agreement with the available experimental information. The results given can be used for the identification of energy levels not yet observed.
The Vacuum Ultraviolet Spectrum of Selenium Hydride I. Determination of the Ground State Spin-Orbit Coupling Constant
Authors: P Bollmark  , B Lindgren  , B Rydh  , U Sassenberg
Published: January 2007

In the wavelength region 1700-1900 Å an electronic transition in the SeH (SeD) molecule is observed. Even though the bands are so diffuse that the rotational structure is almost unresolved, the transition can be identified as the B
2Σ-X
2Π
i
system and a good determination of the spin-orbit coupling constant A = -1764.4 ± 0.2 cm-1 can be made.
Enhanced Line Radiation from Active Molecular Plasmas Due to Electron Collision Induced Instability
Authors: H Wilhelmsson
Published: January 2007

The present study considers the possibility of obtaining an enhancement of stimulated molecular line radiation as a result of an electron collision induced instability. The growth-rate of the negative energy transverse wave which propagates in the dissipative active molecular plasma medium is calculated. An attempt is made to interpret the observed long-term growth of interstellar OH radiation as such a collision induced instability. A possible role played by the same instability mechanism, e.g., in gas-dynamic or plasmadynamic lasers is also suggested.
Determination of the morphological texture of the fibres in a composite material made from a textile of AISI 316L fibres using a mixed deconvolution/positivity method
Authors: Langelaan G. , Ryelandt S. , Root J. H. , Van Houtte P.
Published: January 2007

The orientation distribution or `morphological texture function' (MTF) of the fibres is determined from measurements of the crystallographic texture of the fibres themselves. From neutron diffraction pole-figure measurements of the fibres in the composite and X-ray diffraction pole figures of the individual fibres, the MTF is determined by a deconvolution. To account for errors in the expansion coefficients due to measurement uncertainties, the deconvolution is performed simultaneously with a positivity criterion in the form of a set of linear equations which may be solved by a least-squares method. This approach is validated using a model system of AISI 316L stainless-steel fibres in an Al–13 wt% Si eutectic casting alloy. The fibres had been spun into yarns and subsequently woven to form a textile. The composite was made by infiltrating a `brick' containing several layers of the textile with the Al alloy. The results of the deconvolution procedure show that the method indeed yields the expected morphological texture. The so-determined MTF is resolved to an angular resolution not attainable by other methods. It also provides a very good estimate of the volume fractions of the different texture components.
Focusing capillary optics for use in solution small-angle X-ray scattering
Authors: Lamb Jessica S. , Cornaby Sterling , Andresen Kurt , Kwok Lisa , Park Hye Yoon , Qiu Xiangyun , Smilgies Detlef-M. , Bilderback Donald H. , Pollack Lois
Published: January 2007

Measurements of the global conformation of macromolecules can be carried out using small-angle X-ray scattering (SAXS). Glass focusing capillaries, manufactured at the Cornell High Energy Synchrotron Source (CHESS), have been successfully employed for SAXS measurements on the heme protein cytochromec. These capillaries provide high X-ray flux into a spot size of tens of micrometres, permitting short exposures of small-volume samples. Such a capability is ideal for use in conjunction with microfluidic mixers, where time resolution may be determined by beam size and sample volumes are kept small to facilitate mixing and conserve material.
Scanning texture analysis of lamellar bone using microbeam synchrotron X-ray radiation
Authors: Wagermaier Wolfgang , Gupta Himadri S. , Gourrier Aurélien , Paris Oskar , Roschger Paul , Burghammer Manfred , Riekel Christian , Fratzl Peter
Published: January 2007

Texture analysis with microbeam scanning diffraction enables the local mapping of three-dimensional crystallite orientation in heterogeneous natural and synthetic materials. Cortical (compact) bone is an example of a hierarchically structured biocomposite, which is built mainly of cylindrical osteons, having a lamellar texture at the micrometre level. In this work, a combination of microbeam synchrotron X-ray texture analysis with thin sections of osteonal bone is used to measure the three-dimensional distribution of thec-axis orientation of the mineral apatite in bone with positional resolution of 1 µm. The data reduction procedure needed to go from the stereographic projection of X-ray intensity to the determination of the local orientation of mineralized collagen fibrils is described. The procedure can be applied to other mineralized tissues (such as trabecular bone and chitin) with micrometre scale and biologically controlled fibrillar texture.
Successful protein cryocooling for powder diffraction
Authors: Jenner Mark J. , Wright Jonathan P. , Margiolaki Irene , Fitch Andrew N.
Published: January 2007

It is shown that samples of microcrystalline tetragonal chicken egg white lysozyme can be effectively cryoprotected for high-resolution synchrotron X-ray powder diffraction studies at 100 K. The survival of the powder in the beam is increased by a factor of around 30. Thus, a high-quality powder diffraction pattern could be collected at 100 K, which attains a resolution ofdmin≃ 2.6 Å, significantly better than the previous limit of ∼3.27 Å at room temperature, despite a smaller volume of sample. Systematic variations of the concentration and type of cryoprotectant agent show that the lattice microstrains that accompany cooling, and degrade the quality of the powder diffraction data by broadening the diffraction peaks, are caused by a collapse in the volume of the crystalline unit cell.
Effective hydrostatic limits of pressure media for high-pressure crystallographic studies
Authors: Angel Ross J. , Bujak Maciej , Zhao Jing , Gatta G. Diego , Jacobsen Steven D.
Published: January 2007

The behavior of a number of commonly used pressure media, including nitrogen, argon, 2-propanol, a 4:1 methanol–ethanol mixture, glycerol and various grades of silicone oil, has been examined by measuring the X-ray diffraction maxima from quartz single crystals loaded in a diamond-anvil cell with each of these pressure media in turn. In all cases, the onset of non-hydrostatic stresses within the medium is detectable as the broadening of the rocking curves of X-ray diffraction peaks from the single crystals. The onset of broadening of the rocking curves of quartz is detected at ∼9.8 GPa in a 4:1 mixture of methanol and ethanol and at ∼4.2 GPa in 2-propanol, essentially at the same pressures as the previously reported hydrostatic limits determined by other techniques. Gigahertz ultrasonic interferometry was also used to detect the onset of the glass transition in 4:1 methanol–ethanol and 16:3:1 methanol–ethanol–water, which were observed to support shear waves above ∼9.2 and ∼10.5 GPa, respectively, at 0.8–1.2 GHz. By contrast, peak broadening is first detected at ∼3 GPa in nitrogen, ∼1.9 GPa in argon, ∼1.4 GPa in glycerol and ∼0.9 GPa in various grades of silicone oil. These pressures, which are significantly lower than hydrostatic limits quoted in the literature, should be considered as the practical maximum limits to the hydrostatic behavior of these pressure media at room temperature.
Microstructural characterization of ball-milled α-Al2O3: bimodal size distribution and shape anisotropy
Authors: Deb Apurba Kanti , Chatterjee Partha , Sen Gupta Siba Prasad
Published: January 2007

α-Al2O3prepared by combustion technique was ball-milled in a planetary ball-mill for several hours. A detail microstructural characterization of the ball-milled samples was performed by X-ray line broadening analysis. X-ray diffraction patterns from the milled materials showed super-Lorentzian peak shapes for the α-Al2O3peak profiles, attributed to a bimodal size distribution of the α-Al2O3crystallites, one type of crystallites having spherical and the other having cylindrical morphology. Rietveld analysis using two different phase fractions of α-Al2O3with different microstructural features yielded a low goodness-of-fit of the X-ray data, indicating the suitability of the assumed model.
Superstructure phase in the binary C28H58:C36H/D74system
Authors: Chandra Lydon , Buckley C. E. , Connolly Joan , Norén Lasse , Lockhart Gordon , Gilbert Elliot
Published: January 2007

Blends of the normal alkane C28H58with either protonated or deuterated C36alkane,xC28H58.(1 −x)C36H/D74, have been rapidly cooled from the melt and aged under ambient conditions for at least seven months. For compositions 0.94 ≥x≥ 0.65, both Bragg peaks and associated satellite peaks appear in the small-angle X-ray scattering. The Bragg peaks may be indexed to multiple order reflections from the average spacing of the chain lengths of the two components. The offset inqbetween these peaks is constant for each composition, but dependent on molar composition, and indicates that a superstructure phase forms on prolonged annealing. This new phase appears to be a solid solution and is found for both the protonated and deuterated samples, with a larger cell in the former system. For the remaining compositions, additional peaks indicate formation of a C36-rich phase.
The CCP13FibreFixprogram suite: semi-automated analysis of diffraction patterns from non-crystalline materials
Authors: Rajkumar Ganeshalingam , AL-Khayat Hind A. , Eakins Felicity , Knupp Carlo , Squire John M.
Published: January 2007

The extraction of useful information from recorded diffraction patterns from non-crystalline materials is non-trivial and is not a well defined operation. Unlike protein crystallography where one expects to see well behaved diffraction spots in predictable positions defined by standard space groups, the diffraction patterns from non-crystalline materials are very diverse. They can range from uniaxially oriented fibre patterns which are completely sampled as Bragg peaks, but rotationally averaged around the fibre axis, to fibre patterns that are completely unsampled, to either kind of pattern with considerable axial misalignment (disorientation), to liquid-like order and even to mixtures of these various structure types. In the case of protein crystallography, the specimen is generated artificially and only used if the degree of order is sufficient to yield a three-dimensional density map of high enough resolution to be interpreted sensibly. However, with non-crystalline diffraction, many of the specimens of interest are naturally occurring (e.g.cellulose, rubber, collagen, muscle, hair, silk) and to elucidate their structure it is necessary to extract structural information from the materials as they actually are and to whatever resolution is available. Even when synthetic fibres are generated from purified components (e.g.nylon, polyethylene, DNA, polysaccharides, amyloidsetc.) and diffraction occurs to high resolution, it is rarely possible to obtain perfect uniaxial alignment. The CCP13 project was established in the 1990s to generate software which will be generally useful for analysis of non-crystalline diffraction patterns. Various individual programs were written which allowed separate steps in the analysis procedure to be carried out. Many of these programs have now been integrated into a single user-friendly package known asFibreFix, which is freely downloadable from http://www.ccp13.ac.uk. Here the main features ofFibreFixare outlined and some of its applications are illustrated.
Fortran90 sources of the subroutines ofUMWEG. III. TheUMWEG-specific subroutines
Authors: Rossmanith Elisabeth
Published: January 2007

The Fortran90 sources of theUMWEG-specific subroutines of the programUMWEGare presented and deposited, together with the PostScript-plot software subroutines and the simple and short main program of the command-line version of the programUMWEG.
DRAWxtl, an open-source computer program to produce crystal structure drawings
Authors: Finger Larry W. , Kroeker Martin , Toby Brian H.
Published: January 2007

The computer programDRAWxtlproduces crystal structure drawings in the form of an interactive screen representation, as well as VRML files for use on web pages and in classroom teaching, and creates input files for the popularPersistence of Vision Raytracer(POV-Ray) rendering program for publication-quality graphics, including generation of stereo pairs.DRAWxtloutput produces the standard kinds of graphical representations: spheres, ellipsoids, bonds and polyhedra of any complexity. In addition, it can draw arrows to represent magnetic moments, show capped cones to indicate the location of lone-pair electrons and display Fourier contours in three dimensions. A unique feature of this program is the ability to plot incommensurately modulated and composite structures. This open-source program can be used with operating systems as diverse as Windows (9X, NT, 2000 and XP), Mac OS X, Linux and most other varieties of Unix.
Application of time‐resolved fluorometry to immunoassays for bovine reproductive hormones
Authors: KANEKO Hiroyuki , HASEGAWA Yoshihisa
Published: January 2007

The principle of time‐resolved fluorometry with lanthanide chelates was established in the 1980s, but in the field of animal sciences it has not been widely applied to immunoassays. However, immunoassays that utilize time‐resolved fluorometry are possible alternatives to radioimmunoassays, since they can attain high sensitivity without safety risks. In this short review, we introduce the development of time‐resolved immunoassays for inhibin A, inhibin B and follicle‐stimulating hormone (FSH), and describe their application to the investigation of FSH regulation in male and female cattle. The results obtained using these newly developed immunoassays indicate that inhibin A acts as a feedback regulator for FSH secretion in female cattle, whereas inhibin A, and probably inhibin B, do so in male cattle.
Antiradical function of sulfhydryl residues and oxidative stress markers in dairy cattle plasma
Authors: TANAKA Masahito , KAMIYA Yuko , KAMIYA Mitsuru , SHIOYA Shigeru , NAKAI Yutaka
Published: January 2007

The antiradical function of sulfhydryl (SH) residue in dairy cattle plasma and the relationship of SH residue concentrations to other oxidative stress markers, ascorbic acid and thiobarbituric acid reactive substance (TBARS) in plasma were investigated. The concentration of reduced glutathione (GSH) in phosphate buffer solution (pH 7.6) and SH residues in dairy cattle plasma decreased significantly (P < 0.05) in vitro by the addition of peroxyradicals at 38°C, depending on incubation periods. The decrease of GSH concentration with the peroxyradical solution was partially protected by the addition of sodium ascorbate solution. A positive and significant correlation with SH residues and albumin concentration in the fresh plasma obtained from 15 dairy cattle was observed (P < 0.05). The SH residue concentration was not correlated with the TBARS concentration in plasma. The total ascorbic acid and SH residues concentration in the plasma correlated positively but not significantly (P < 0.10). These results suggested that SH residues in dairy cattle plasma play important part in the antiradical function.
Major microbiota of lactic acid bacteria from Matsoni, a traditional Georgian fermented milk
Authors: UCHIDA Kenji , URASHIMA Tadasu , CHANISHVILI Nino , ARAI Ikiti , MOTOSHIMA Hidemasa
Published: January 2007

A total of 26 samples of Matsoni were collected in Georgia. From these samples 80 strains of lactic acid cocci and 173 strains of lactobacilli were isolated. The number of lactic acid bacteria varied between 105 and 1010 colony forming unit (CFU)/mL. All the isolated lactic acid bacteria were thermophilic bacteria that could grow at 45°C. The predominant lactic acid bacteria were Streptococcus thermophilus and Lactobacillus delbrueckii spp. bulgaricus in 25 samples of Matsoni, while Lactobacillus helveticus was also a predominant species, together with the two previous species in one sample of Matsoni. We showed there was diversity in both S. thermophilus and L. delbrueckii spp. bulgaricus at the strain level by randomly amplified polymorphic DNA analysis.
A cell wall preparation of Enterococcus faecalis strain EC‐12 stimulates β‐defensin expression in newly hatched broiler chicks
Authors: SAKAI Yuri , TSUKAHARA Takamitsu , MATSUBARA Noritaka , USHIDA Kazunari
Published: January 2007

In our previous study, a cell wall preparation of Enterococcus faecalis strain EC‐12 (EC‐12) prevented the colonization of vancomycin‐resistant enterococci (VRE) in newly hatched broiler chicks. Relatively early prevention against VRE colonization by EC‐12 administration may be related to the enhanced innate immune system. In this study we examined the effect of EC‐12 on the kinetics of immunoglobulin A (IgA) concentration in the cecal digesta of chicks from 1 day to 14 days old to evaluate humoral immunity. We also examined the effect of EC‐12 on β‐defensin mRNA expression and lysozyme production. The IgA concentration in the cecal digesta showed a decline in chicks from 2 to 8 days old and then a recovery up to when they were 14 days old. The concentration tended to be higher in EC‐12‐administered chicks than in control chicks at 14 days old. EC‐12 administration did not stimulate the lysozyme activities in the alimentary tract. However, β‐defensin mRNA expression in the tongue and the bursa of Fabricius was higher in chicks administered EC‐12 than in the control chicks at 5 days old. These results indicate that β‐defensin may be one of the major defense mechanisms inhibiting VRE colonization in young chicks.
Video of a disaster drill is effective in educating registrars on the hospital disaster plan
Authors: Bartley Bruce , Fisher Julia , Stella Julian
Published: January 2007

Objective:  To test whether an instructional video of edited footage from a disaster drill is effective in educating registrars on the hospital disaster plan.

Methods:  This was a prospective pre‐ and post‐intervention study. Forty hospital registrars were shown a 15 min video based on footage obtained at a simulated mass casualty incident. The video provided information on the ED disaster response plan and principles of hospital disaster management. A survey was developed to assess disaster plan knowledge before and after viewing the video. The survey had a predetermined ‘pass mark’ of 14/20 (70%).

Results:  Thirty‐nine registrars completed the surveys. Three of 39 (7.7% 95% confidence interval [CI] 7.0–8.3%) registrars achieved the pass mark in the pre‐video survey and 35/39 (89.7% 95% CI 81.2–98.3%) registrars achieved the pass mark in the post‐video survey (χ2‐test P < 0.001) with an absolute increase in the pass rate of 82% (95% CI 75.8–88.2%).

Conclusion:  This finding justifies compulsory viewing of the video in the registrar orientation package locally and might encourage more widespread use of educational video in hospital disaster preparedness.
Attachment and Sexual Health Behaviors in Homeless Youth
Authors: Taylor‐Seehafer Margaret , Johnson Regina , Rew Lynn , Fouladi Rachel T. , Land Lee , Abel Elizabeth
Published: January 2007

PURPOSE.  To explore relationships and group differences in attachment‐related constructs (social connectedness and social support) and sexual health behaviors in a sample of homeless youth.

DESIGN AND METHODS.  An exploratory design, this study analyzed baseline data from an ongoing intervention study. Survey data were collected by audio, computer‐assisted self‐interview (A‐CASI) from a nonprobability sample of homeless youth (n = 176).

RESULTS.  Social connectedness was positively correlated with period of time homeless, while social support was positively related to sexual self‐concept and to self‐efficacy and intention to use condoms.

PRACTICE IMPLICATIONS.  The street group that homeless youth identify with may be a potential resource for peer‐mentoring and skill‐building regarding healthy sexual behavior.
Accuracies of β-Lactam Susceptibility Test Results for
Pseudomonas aeruginosa
with Four Automated Systems (BD Phoenix, MicroScan WalkAway, Vitek, and Vitek 2)
Authors: Juretschko Stefan , LaBombardi Vincent J. , Lerner Stephen A. , Schreckenberger Paul C. ,   and the Pseudomonas AST Study Group
Published: January 2007

Contemporary clinical isolates and challenge strains of
Pseudomonas aeruginosa
were tested by four automated susceptibility testing systems (BD Phoenix, MicroScan WalkAway, Vitek, and Vitek 2; two laboratories with each) against six broad-spectrum β-lactams, and the results were compared to reference broth microdilution (BMD) and to consensus results from three validated methods (BMD, Etest [AB Biodisk, Solna, Sweden], and disk diffusion). Unacceptable levels of error (minor, major, and very major) were detected, some with systematic biases toward false susceptibility (piperacillin-tazobactam and imipenem) and others toward false resistance (aztreonam, cefepime, and ceftazidime). We encourage corrective action by the system manufacturers to address test biases, and we suggest that clinical laboratories using automated systems should consider accurate alternative methods for routine use.
White Spot Syndrome Virus Annexes a Shrimp STAT To Enhance Expression of the Immediate-Early Gene
ie1
Authors: Liu Wang-Jing , Chang Yun-Shiang , Wang Andrew H.-J. , Kou Guang-Hsiung , Lo Chu-Fang
Published: January 2007

Although the Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling pathway is part of the antiviral response in arthropods such as
Drosophila
, here we show that white spot syndrome virus (WSSV) uses a shrimp STAT as a transcription factor to enhance viral gene expression in host cells. In a series of deletion and mutation assays using the WSSV immediate-early gene
ie1
promoter, which is active in shrimp cells and also in insect Sf9 cells, an element containing a STAT binding motif was shown to be important for the overall level of WSSV
ie1
promoter activity. In the Sf9 insect cell line, a specific protein-DNA complex was detected by using electrophoresis mobility shift assays (EMSA) with the
32
P-labeled STAT binding motif of the WSSV
ie1
promoter as the probe. When recombinant
Penaeus monodon
STAT (rPmSTAT) was overexpressed in Sf9 cells, EMSA with specific antibodies confirmed that the STAT was responsible for the formation of the specific protein-DNA complex. Another EMSA showed that in WSSV-infected
P. monodon
, levels of activated PmSTAT were higher than in WSSV-free
P. monodon
. A transactivation assay of the WSSV
ie1
promoter demonstrated that increasing the level of rPmSTAT led to dose-dependent increases in
ie1
promoter activity. These results show that STAT directly transactivates WSSV
ie1
gene expression and contributes to its high promoter activity. We conclude that WSSV successfully annexes a putative shrimp defense mechanism, which it uses to enhance the expression of viral immediate-early genes.
Inter-rater agreement in the assessment of exposure to carcinogens in the offshore petroleum industry
Authors: Steinsvåg Kjersti , Bråtveit Magne , Moen Bente E , Kromhout Hans
Published: January 2007

Objectives:To evaluate the reliability of an expert team assessing exposure to carcinogens in the offshore petroleum industry and to study how the information provided influenced the agreement among raters.

Methods:Eight experts individually assessed the likelihood of exposure for combinations of 17 carcinogens, 27 job categories and four time periods (1970–1979, 1980–1989, 1990–1999 and 2000–2005). Each rater assessed 1836 combinations based on summary documents on carcinogenic agents, which included descriptions of sources of exposure and products, descriptions of work processes carried out within the different job categories, and monitoring data. Inter-rater agreement was calculated using Cohen’s kappa index and single and average score intraclass correlation coefficients (ICC) (ICC(2,1)and ICC(2,8), respectively). Differences in inter-rater agreement for time periods, raters, International Agency for Research on Cancer groups and the amount of information provided were consequently studied.

Results:Overall, 18% of the combinations were denoted as possible exposure, and 14% scored probable exposure. Stratified by the 17 carcinogenic agents, the probable exposure prevalence ranged from 3.8% for refractory ceramic fibres to 30% for crude oil. Overall mean kappa was 0.42 (ICC(2,1) = 0.62 and ICC(2,8) = 0.93). Providing limited quantitative measurement data was associated with less agreement than for equally well described carcinogens without sampling data.

Conclusion:The overall κ and single-score ICC indicate that the raters agree on exposure estimates well above the chance level. The levels of inter-rater agreement were higher than in other comparable studies. The average score ICC indicates reliable mean estimates and implies that sufficient raters were involved. The raters seemed to have enough documentation on which to base their estimates, but provision of limited monitoring data leads to more incongruence among raters. Having real exposure data, with the inherent variability of such data, apparently makes estimating exposure in a rigid semiquantitative manner more difficult.
Taxonomy, ecology, and biogeography of polypores (Basidiomycetes) from Argentinian Polylepis woodlands
Authors: Robledo Gerardo , Urcelay Carlos , Domínguez Laura , Rajchenberg Mario
Published: January 2007

Twenty-three polypore species were found in Polylepis Ruiz & Pav. (Rosacecae) woodlands from Argentina. Six species occur exclusively in the neotropics and four are host-specific to Polylepis ( Phellinus tabaquilio , Phellinus uncisetus , Phellinus daedaliformis , and Datronia orcomanta ), of which the first two are facultative parasites or occur during the early stages of wood decay. Host specificity and patterns of distribution vary among species. Datronia orcomanta Robledo & Rajchenb. is described as a new endemic taxon and Inonotus serranus is reduced to synonymy with Inonotus venezuelicus .
Two threatened coexisting indigenous conifer species in the dry Afromontane forests of Ethiopia are associated with distinct arbuscular mycorrhizal fungal communities
Authors: Wubet Tesfaye , Weiß Michael , Kottke Ingrid , Oberwinkler Franz
Published: January 2007

The molecular diversity of arbuscular mycorrhizal (AM) fungi colonizing roots of Podocarpus falcatus (Thunb.) R.Br. (Podocarpaceae) in the dry Afromontane forests of Ethiopia was investigated. The nuclear gene coding for small subunit ribosomal RNA (nucSSU rDNA) was amplified from colonized roots of P. falcatus, cloned, and sequenced using AM fungal specific primers. Phylogenetic analyses revealed that the glomeromycetous sequences from mycorrhizae of P. falcatus belong to the Glomeraceae, Diversisporaceae, and Archaeosporaceae. Overall, 16 Glomus , three Diversispora , and one Archaeospora sequence types were identified. These sequence types were distinct and only distantly related to sequences from the available defined species. The composition of the AM fungal communities differed significantly between the two study sites. Comparison of the AM fungal community composition of P. falcatus with that of previously investigated Juniperus procera Hochst. ex Endl. (Cupressaceae), the only coexisting indigenous conifer tree species in the dry Afromontane forest ecosystem, yields that the two tree species are colonized by distinct AM fungal communities. This suggests that fungal communities are host plant specific in the natural stand conditions. Therefore, in the conservation of these endangered species and restoration of the degraded ecosystem, the use of appropriate mycorrhizal fungi should be taken into account in future projects.
Proterozoic evolution of the western margin of the Wyoming craton: implications for the tectonic and magmatic evolution of the northern Rocky Mountains
Authors: Foster David A , Mueller Paul A , Mogk David W , Wooden Joseph L , Vogl James J
Published: January 2007

Defining the extent and age of basement provinces west of the exposed western margin of the Archean Wyoming craton has been elusive because of thick sedimentary cover and voluminous Cretaceous–Tertiary magmatism. U–Pb zircon geochronological data from small exposures of pre-Belt supergroup basement along the western side of the Wyoming craton, in southwestern Montana, reveal crystallization ages ranging from ~2.4 to ~1.8 Ga. Rock-forming events in the area as young as ~1.6 Ga are also indicated by isotopic (Nd, Pb, Sr) signatures and xenocrystic zircon populations in Cretaceous–Eocene granitoids. Most of this lithosphere is primitive, gives ages ~1.7–1.86 Ga, and occurs in a zone that extends west to the Neoproterozoic rifted margin of Laurentia. These data suggest that the basement west of the exposed Archean Wyoming craton contains accreted juvenile Paleoproterozoic arc-like terranes, along with a possible mafic underplate of similar age. This area is largely under the Mesoproterozoic Belt basin and intruded by the Idaho batholith. We refer to this Paleoproterozoic crust herein as the Selway terrane. The Selway terrane has been more easily reactivated and much more fertile for magma production and mineralization than the thick lithosphere of the Wyoming craton, and is of prime importance for evaluating Neoproterozoic continental reconstructions.
2480 Ma mafic magmatism in the northern Black Hills, South Dakota: a new link connecting the Wyoming and Superior cratons
Authors: Dahl Peter S , Hamilton Michael A , Wooden Joseph L , Foland Kenneth A , Frei Robert , McCombs James A , Holm Daniel K
Published: January 2007

The Laramide Black Hills uplift of southwest South Dakota exposes a Precambrian crystalline core of ~2560–2600 Ma basement granitoids nonconformably overlain by two Paleoproterozoic intracratonic rift successions. In the northern Black Hills, a 1 km thick, layered sill (the Blue Draw metagabbro) that intrudes the older rift succession provides a key constraint on the timing of mafic magmatism and of older rift-basin sedimentation. Ion microprobe spot analyses of megacrysts of magmatic titanite from a horizon of dioritic pegmatite in the uppermost sill portion yield a 207Pb/206Pb upper-intercept age of 2480 ± 6 Ma (all age errors ±2σ), comparable to two-point 207Pb/206Pb errorchron ages obtained by Pb stepwise leaching of the same titanites. Nearly concordant domains in coexisting magmatic zircon yield apparent spot ages ranging from 2458 ± 16 to 2284 ± 20 Ma (i.e., differentially reset along U–Pb concordia), and hornblende from an associated metadiorite yields a partially reset date with oldest apparent-age increments ranging between 2076 ± 16 and 2010 ± 8 Ma. We interpret these data as indicating that an episode of gabbroic magmatism occurred at 2480 Ma, in response to earlier rifting of the eastern edge of the Wyoming craton. Layered mafic intrusions of similar thickness and identical age occur along a rifted belt in the southern Superior craton (Sudbury region, Ontario). Moreover, these mafic intrusions are spatially aligned using previous supercontinent restorations of the Wyoming and Superior cratons (Kenorland–Superia configurations). This new "piercing point" augments one previously inferred by spatial–temporal correlation of the Paleoproterozoic Huronian (southern Ontario) and Snowy Pass (southeastern Wyoming) supergroups. We propose that layered mafic intrusions extending from Nemo, South Dakota, to Sudbury, Ontario, delineate an axial rift zone along which Wyoming began to separate from Superior during initial fragmentation of the Neoarchean supercontinent at ≥2480 Ma.
The Wyoming Province: a distinctive Archean craton in Laurentian North America
Authors: Mueller P A , Frost C D
Published: January 2007

The Wyoming Province is a distinctive Archean craton in the northwestern United States that can be subdivided into three subprovinces, namely, from oldest to youngest, the Montana metasedimentary province, the Beartooth–Bighorn magmatic zone, and the Southern accreted terranes. Archean rocks of the Montana metasedimentary province and the Beartooth–Bighorn magmatic zone are characterized by (1) their antiquity (rock ages to 3.5 Ga, detrital zircon ages up to 4.0 Ga, and Nd model ages exceeding 4.0 Ga); (2) a distinctly enriched 207Pb/204Pb isotopic signature, which suggests that this part of the province was not produced by the amalgamation of exotic terranes; and (3) a distinctively thick (15–20 km), mafic lower crust. The Montana metasedimentary province and Beartooth–Bighorn magmatic zone were cratonized by about 3.0–2.8 Ga. Crustal growth occurred via continental-arc magmatism and terrane accretion in the Southern accreted terranes along the southern margin of the province at 2.68–2.50 Ga. By the end of the Archean, the three subprovinces were joined as part of what is now the Wyoming Province. Subsequent to amalgamation of the Wyoming crust to Laurentia at ca. 1.8–1.9 Ga, Paleoproterozoic crust (1.7–2.4 Ga) was juxtaposed along the southern and western boundaries of the province. Subsequent tectonism and magmatism in the Wyoming region are concentrated in the areas underlain by these Proterozoic mobile belts.
Tectonic histories of the Paleo- to Mesoarchean Sacawee block and Neoarchean Oregon Trail structural belt of the south-central Wyoming Province
Authors: Grace Rashmi LB , Chamberlain Kevin R , Frost B Ronald , Frost Carol D
Published: January 2007

The Sacawee block is a narrow belt of Paleo- to Mesoarchean crust that extends for ~70 km across the northern Granite Mountains. It is composed of the ~3.3 Ga Sacawee orthogneiss, additional calc-alkalic and tonalitic orthogneisses, and the ~2.86 Ga Barlow Gap Group. The Sacawee block basement is characterized by negative εNdvalues and Paleoarchean Nd crustal residence model ages. A broad east–west-trending zone of Neoarchean high strain, which is part of the Oregon Trail structural belt, transects the Sacawee block and was studied at two locations, the Beulah Belle Lake area and West Sage Hen Rocks. U–Pb analyses of magmatic zircon from a sheared amphibolite within the high-strain zone of the Beulah Belle Lake area constrain the age of the Neoarchean deformation to be later than 2688 ± 5 Ma. At West Sage Hen Rocks, metamorphic zircons in a sheared amphibolite provide a direct date on the shear zone of 2649 ± 2.8 Ma. These data, combined with similar ages of deformation from two other shear zones, are interpreted to suggest that the Neoarchean Oregon Trail structural belt is a pervasive feature of the Sacawee block and may represent a deformation front related to accretion. Multiple east–west-trending shear zones within the Sacawee block are evidence for tectonic modification of the crust between ~2.65 and 2.63 Ga and horizontal convergence analogous to modern plate tectonics processes. The Sacawee block is either a rare exposure of ancient basement typical of that which originally underlay much of the Wyoming Province or it is an exotic block that was accreted to the core of the Wyoming Province in Neoarchean time.
Relationships among nutrients, algae, and land use in urbanized southern California streams
Authors: Busse Lilian B , Simpson Juliet C , Cooper Scott D
Published: January 2007

We surveyed algal cover, algal biomass, and physical and chemical factors at 14 sites representing a range of land use types in the Malibu Creek watershed in southern California, USA. We also conducted nutrient diffuser substrate experiments to identify the nutrient limiting algal growth. Algal biomass increased with urbanization, reaching very high levels in the most urbanized streams (up to 322.4 mg chlorophyll a·m-2). Total nitrogen, total phosphorus, and benthic and total chlorophyll concentrations were positively correlated with the proportion of upstream land covered by impervious surfaces. Relationships between land use and algal biomass or nutrient concentrations were evaluated at 100 m, 500 m, and whole subwatershed scales. The closest relationships were found at the 500 m scale, where 56% of the variation in total chlorophyll could be explained by the proportion of land within a 500 m radius upstream covered by impervious surfaces. Floating macroalgae were observed in the summer in pools with high nutrient and light levels, whereas benthic algal biomass was positively related to total phosphorus concentrations and current speed. Other methods of determining nutrient limitation (nutrient diffuser substrate experiment, molar N/P ratios in stream water) produced conflicting results, possibly because algal growth was saturated by high nutrient levels at some of the study sites.
The genetic structure of Atlantic cod (Gadus morhua) around Iceland: insight from microsatellites, the Pan I locus, and tagging experiments
Authors: Pampoulie Christophe , Ruzzante Daniel E , Chosson Valérie , Jörundsdóttir Thóra Dögg , Taylor Lorna , Thorsteinsson Vilhjálmur , Daníelsdóttir Anna Kristín , Marteinsdóttir Guðrún
Published: January 2007

Allelic variation at nine microsatellite loci and the Pan I locus provides evidence that Atlantic cod (Gadus morhua) around Iceland is genetically structured (FST = 0.003 and FST = 0.261, respectively). A total of 2534 cod were sampled at 22 spawning locations. For both types of markers, most of the significant pairwise FST resulted from northeastern–southwestern comparisons. A multidimensional scaling analysis based on FST, a spatial hierarchical analysis of molecular variance (SAMOVA) and a hierarchical analysis of molecular variance (AMOVA), conducted on both types of markers confirmed a genetic differentiation between cod from the northeastern and southwestern regions. Genetic discontinuities were revealed across two main current fronts in the southeast and northwest, where the cold and warm water masses meet. The AMOVA also detected genetic differences with depth. Expected and observed heterozygosity of microsatellite loci significantly decreased with depth, whereas the B allele frequency at the Pan I locus increased. A tagging experiment of spawning fish conducted during the same years as the genetic work revealed that tagged individuals released in the southwestern region seldom migrated to the northeastern region and vice versa, suggesting that the southwestern and northeastern populations of Atlantic cod around Iceland represent two distinct spawning components.
Fatty acid dynamics during the spring bloom in a High Arctic fjord: importance of abiotic factors versus community changes
Authors: Leu Eva , Falk-Petersen Stig , Kwaśniewski Slawomir , Wulff Angela , Edvardsen Kåre , Hessen Dag O
Published: January 2007

We followed the fatty acid composition of particulate organic matter (POM) in a High Arctic fjord (79°N; Svalbard, Norway) during and after the spring bloom. The content of essential polyunsaturated fatty acids (PUFAs) was highest (45% of total fatty acids) at the beginning of the bloom, well before the biomass maximum, and decreased linearly towards the end (30%). During the postbloom period, the concentrations of PUFAs remained stable, between 25% and 30%. Redundancy analysis was used to identify the environmental factors that explained the observed variability in the fatty acid composition of phytoplankton. A particular emphasis was put on the potential influence of high irradiances. During the spring bloom, nutrient availability (Si and N), as well as shifts in phytoplankton community composition and chlorophyll a, were shown to account for much of the pattern in fatty acid composition. During the postbloom period, particularly during periods of stratification, light had a pronounced effect on the fatty acid composition. In general, we found a decrease in the relative amount of PUFAs under high light intensities and nutrient limitation.
Groundwater modelling of a weathered gneissic cover
Authors: Cascini Leonardo , Gullà Giovanni , Sorbino Giuseppe
Published: January 2007

Knowledge of the groundwater regime, which is generally necessary in studying the stability of slopes, is of fundamental importance in the analysis of landslides involving intensely weathered rocks, as in the case of a landslide in the western Sila Massif (southern Italy) reactivated by heavy and prolonged rainfall. For this landslide, the total absence of displacements during the actual quiescence period and the long return period of the critical rainfall events did not allow measurement of the critical pore pressures capable of reactivating the landslide. To solve such a problem, a saturated–unsaturated flow model was calibrated taking into account in situ pore pressure measurements acquired over a long period of time. The analyses permitted determination of the role played by the hydraulic heterogeneity of the involved soils and the hydraulic boundary conditions for simulation of the response of in situ pore pressures to rainfall. Such conditions were therefore used to predict the critical unknown values attained during landslide reactivations and were indirectly tested using different models.Key words: landslide, weathered rocks, groundwater monitoring, unsaturated–saturated flow model, rainfall, critical pore pressures.