bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigating Motivation in Context
Authors: Walker Richard A. , Pressick-Kilborn Kimberley , Arnold Lynette S. , Sainsbury Erica J.
Published: October 2004

Motivation is increasingly recognized as contextually situated, and this recognition has led to considerable research into motivation in authentic learning environments such as classrooms. Developing sociocultural perspectives on motivation, however, requires consideration of theoretical issues beyond those of context. This article discusses two separate empirical studies that are grounded in sociocultural principles in that they reconceptualize the constructs of interest and student regulatory activities as fundamentally social in nature and origin. Using multiple methodologies that allow focus at the levels of both classroom and individual, these studies employ the notion of transformative internalization and subsequent externalization to explain the social origins of individual motivational processes. The study of interest followed a small group of students within a primary science classroom, and employed a range of qualitative methods including observation of lessons, the videotaping of lesson segments, interviews with students, and written student reflections. The study of student regulatory activities investigated the impact of a teaching intervention in primary social studies classrooms, and used a combination of quantitative (questionnaire-based) and qualitative methods (semistructured interviews, observations of classroom activities, and student reflections). Both studies contribute to the development of sociocultural perspectives on motivation through empirical research guided by such theoretical notions as intersubjectivity, canalization, and coregulation.
Comments on Motivation in Real-Life, Dynamic, and Interactive Learning Environments
Authors: Winne Philip H.
Published: October 2004

Articles published in this special section report state-of-the-art research on motivation and related constructs by studying learners in authentic and dynamic situations. Each research team demonstrates the value of using multiple methodologies. I draw out four themes that illuminate critical issues in this area of research: First, learners hold multiple goals simultaneously. Second, holding multiple goals affords opportunities for self-regulation. Third, goals and motivation evolve over time, although we know little about the trajectory of this process. Fourth, investigations that adopt multiple methodologies create opportunities to accelerate progress in the field. I also offer an alternative interpretive stance, a cognitive one, for theorizing about these constructs. I attempt to stimulate alternative but not antithetical views for future research about motivational constructs and their relations to learners' participation in classroom activities and achievements.
Professional Ethics Across National Boundaries
Authors: Pettifor Jean L.
Published: October 2004

The International Union of Psychological Science is searching for ethical principles that are universal for the discipline of psychology. Codes of ethics adopted by other international organizations are reviewed, as well as recent comparisons of psychology codes across national boundaries. Distinctions are made between declarations of human rights and professional codes of ethics, between ethical principles as overarching values and as rules of conduct, and between Euro-North American and non-Western cultural values. Organizations such as the United Nations and Amnesty International work for the elimination of abuses of human rights. Professional associations establish guidelines to promote the ethical behavior of their members. The hope for articulating universal ethical principles for psychologists is based on respect for our common humanity while still respecting the diversity of beliefs in different cultures.
Effects of level and quality of organic matter input on carbon storage and biological activity in soil: Synthesis of a long‐term experiment
Authors: Kirchmann Holger , Haberhauer Georg , Kandeler Ellen , Sessitsch Angela , Gerzabek Martin H.
Published: October 2004

The aim of this paper was to synthesize a series of investigations from a long‐term field experiment addressing the turnover of organic matter in soil. This paper is based on four organic matter inputs (soil treatments): none (fallow), small amounts of roots+stubble cropped without N fertilizer (no‐N), moderate additions of animal manure, and moderate additions of peat. After 42 years, soil carbon stocks declined in the fallow and no‐N treated soil but increased in the animal manure and peat‐amended soil. Gentle fractionation of soil particles and aggregates revealed that the silt‐sized fraction contained most of the soil C and was most responsive to changes in input of organic matter. The clay‐sized fraction (<2 μm) acted as a sink for C, and amounts of clay‐sized C increased in all treatments, including fallow. The contribution of size fractions to C storage decreased in the following order: silt > clay > fine sand > coarse sand. The highest natural abundance of 13C and 15N was found in the clay‐sized fraction, the fallow being most enriched in 13C and the animal manure‐treated soil in 15N, indicating that the organic matter of the clay‐sized fraction had been turned over most intensively. The 13C inventory showed that the transfer from silt‐ to clay‐sized carbon was most intensive in the soil treated with animal manure and least intensive in the peat‐treated soil. Bacterial diversity increased from sand‐ to clay‐sized fractions revealed by 16S rRNA genes. Fungal activity was highest in coarse‐sized fractions as indicated by enzyme measurements. The quality and amount of organic matter input had no significant effect on the community structure of soil bacteria.
Mixing in a coastal environment: 2. A view from microstructure measurements
Authors: Oakey Neil S. , Greenan Blair J. W.
Published: October 2004

During the Coastal Mixing and Optics Experiment in 1996 and 1997, an integrated dye and microstructure experiment was done to measure and compare mixing rates on the continental shelf. The results of the dye experiment are presented in the companion paper by Ledwell et al. [2004]. In this paper, we explore the results from microstructure measurements using a vertical profiling instrument. We measure temperature and velocity microstructure and, along with simultaneous measurements of salinity and temperature as well as a shipboard acoustic Doppler current profiler (ADCP), are able to estimate the vertical diffusivities of heat, mass, and momentum. In three of four dye injections performed, we were able to make a comparison of the diffusivity from both dye and microstructure measurements. Although the mixing rates were quite small (vertical diffusivity of heat, KT < 10−5 m2 s−1), the two techniques yielded consistent results. A comparison of the vertical diffusivities KT and Kρ (the vertical diffusivity for density) allowed us to determine a flux Richardson number of Rf = 0.16 ± 0.03. Rf showed little dependence on either the buoyancy frequency, N, or gradient Richardson number, Ri. A clear relationship was found between the ratio of diffusivities, Km/KT and Ri consistent with Km/KT = 5 Ri. Turbulence levels were extremely low, with Cox numbers in one experiment of about 20 and in the other three of about 5 (i.e., KT about 20 and 5 times molecular diffusion, respectively).
Mixing in a coastal environment: 1. A view from dye dispersion
Authors: Ledwell James R. , Duda Timothy F. , Sundermeyer Miles A. , Seim Harvey E.
Published: October 2004

Dye release experiments were performed together with microstructure profiling to compare the two methods of estimating diapycnal diffusivity during summer and fall stratification on the continental shelf south of New England. The experiments were done in 1996 and 1997 as part of the Coastal Mixing and Optics Experiment. During the 100 hours or so of the experiments the area of the dye patches grew from less than 1 km2 to more than 50 km2 [Sundermeyer and Ledwell, 2001]. Diapycnal diffusivities inferred from dye dispersion range from 10−6 to 10−5 m2/s at buoyancy frequencies from 9 to 28 cycles/hour. Diffusivities estimated from the dye and those estimated from dissipation rates in the companion paper by Oakey and Greenan [2004] agree closely in most cases. Estimates of diffusivities from towed conductivity microstructure measurements made during the cruises by Duda and Rehmann [2002] and Rehmann and Duda [2000] are fairly consistent with the dye diffusivities. The dye diffusivities would be predicted well by an empirical formula involving shear and stratification statistics developed by MacKinnon and Gregg [2003] from profiling microstructure measurements obtained at the same site in August 1996. All of the measurements support the general conclusion that the diffusivity, averaged over several days, is seldom greater than 10−5 m2/s in the stratified waters at the site, and usually not much greater than 10−6 m2/s. Severe storms, such as a hurricane that passed over the CMO site in 1996, can dramatically increase the mixing at the site, however.
Focused magmatism versus amagmatic spreading along the ultra‐slow spreading Southwest Indian Ridge: Evidence from TOBI side scan sonar imagery
Authors: Sauter Daniel , Mendel Véronique , Rommevaux‐Jestin Céline , Parson Lindsay M. , Fujimoto Hiromi , Mével Catherine , Cannat Mathilde , Tamaki Kensaku
Published: October 2004

The analysis of the Towed Ocean Bottom Instrument (TOBI) side scan sonar images along the Southwest Indian Ridge between 63°40′E and 65°40′E reveals strong focusing of magmatic activity and long amagmatic accretionary ridge segments. Fresh‐looking volcanic terrains are observed at distinct locations along the axis separated by highly tectonized and sedimented terrains of an along‐axis extent as much as 82 km. The largest tectonized section corresponds to a dramatically thin crust area with moderate magnetization anomalies. We suggest that seafloor spreading is mainly amagmatic in this tectonized section of the Southwest Indian Ridge with upper mantle rocks exposed at the seafloor. Amagmatic accretionary ridge segments of such dimensions are quite distinct from what is observed at the Mid‐Atlantic Ridge but are also recognized at the Gakkel Ridge and may thus be characteristic of ultra‐slow spreading ridges. The correlation between the distribution of fresh‐looking volcanic terrains, the occurrence of shallow areas crowned by axial volcanic ridges, and high magnetization values suggests a shallow segmentation of the ridge mainly related to variation in the thickness and/or the intrinsic magnetization of the basaltic source layer. By contrast, strong along‐axis variations of the gravity‐derived crustal thickness are shrunken in length relative to this shallow segmentation of the ridge and occur only beneath the elevated segments. Adjacent to these elevated segments, small bathymetric swells with fresh‐looking volcanic constructions do not correspond to thicker crust areas. This suggests a highly focused melt supply beneath the elevated segments which may feed volcanic constructions up to 60 km from the center of these segments by shallow lateral melt migration in the crust, probably through large dikes. Neither the ultra‐slow spreading rate nor the ridge obliquity explains the variation of the magmatic vigor along the ridge. Mantle source heterogeneities together with lower mantle temperatures beneath the easternmost Southwest Indian Ridge could partly control its segmentation.
Equation of state and elasticity of FeSi
Authors: Caracas R. , Wentzcovitch R.
Published: October 2004

FeSi may be one of the main products of the reaction between molten iron and mantle silicates. We use both the Local Density Approximation (LDA) and the Generalized Gradient Approximation (GGA) to Density Functional Theory (DFT) to analyze the structural behavior of FeSi and to determine its elastic properties up to high pressures. According to our calculations, at lowermost mantle pressure conditions, FeSi is in the B2 (CsCl‐type) structure. The B20‐B2 transition takes place at 30 GPa in LDA and 40 GPa in GGA and is characterized by a 0.35 g/cm3 shift in density.
On effect of wave breaking on short wind waves
Authors: Kudryavtsev Vladimir , Johannessen Johnny
Published: October 2004

The paper presents an attempt to estimate short wave generation by wave breaking. A breaking wave crest disturbs the surface and generates sub‐surface turbulence. The locally disturbed area further disperses and feeds short wave energy to the surroundings. The total short wave energy results from summing up the effect of wave breaking events randomly distributed over the sea surface. The rate of short wave generation is determined by the frequency of wavebreaking events per unit area. The source of short wave energy is isotropic, thus it generates waves at cross and opposite wind directions. The model qualitatively reproduces observed directional property of short wind wave spectra and mean square slope.
Local attenuation in western Nagano, central Japan, estimated from seismograms recorded in three boreholes
Authors: Ito Shinobu , Ito Hisao , Horiuchi Shigeki , Iio Yoshihisa
Published: October 2004

Seismic attenuation parameters three borehole stations in Western Nagano, Central Japan. Based on the difference in attenuation between combinations of two boreholes, the local attenuation (QP−1) is 1.23 × 10−3 s in the frequency range of 80 to 250 Hz. Obtained QP−1 is consistent with the trend estimated by grid search with the assumption of the ω2 source model. Even though the boreholes are located on the fracture area of the 1984 Nagano‐Ken‐Seibu Earthquake, the estimated QP−1 is low. The result is not completely consistent with a previous study, and a result of QS−1 obtained from the twofold spectral ratio, but the difference can be interpreted as the difference of frequency ranges. The differences of station corrections of attenuation between boreholes are much smaller than the difference between borehole and surface, and the result shows the advantage of borehole seismometers.
Basin scale estimates of evapotranspiration using GRACE and other observations
Authors: Rodell M. , Famiglietti J. S. , Chen J. , Seneviratne S. I. , Viterbo P. , Holl S. , Wilson C. R.
Published: October 2004

Evapotranspiration is integral to studies of the Earth system, yet it is difficult to measure on regional scales. One estimation technique is a terrestrial water budget, i.e., total precipitation minus the sum of evapotranspiration and net runoff equals the change in water storage. Gravity Recovery and Climate Experiment (GRACE) satellite gravity observations are now enabling closure of this equation by providing the terrestrial water storage change. Equations are presented here for estimating evapotranspiration using observation based information, taking into account the unique nature of GRACE observations. GRACE water storage changes are first substantiated by comparing with results from a land surface model and a combined atmospheric‐terrestrial water budget approach. Evapotranspiration is then estimated for 14 time periods over the Mississippi River basin and compared with output from three modeling systems. The GRACE estimates generally lay in the middle of the models and may provide skill in evaluating modeled evapotranspiration.
Shatter cones: Branched, rapid fractures formed by shock impact
Authors: Sagy Amir , Fineberg Jay , Reches Ze'ev
Published: October 2004

Shatter cones are rock discontinuities known only from sites of extraterrestrial impacts, and they are assumed to be formed by impact‐induced shock waves. Here we characterize the structure of shatter cones by field and microanalyses and explain their formation by dynamic fracture mechanics. Our analyses reveal that shatter cones always occur as multilevel, three‐dimensional networks, 0.01–100 m in size, with hierarchal branched fractures. A typical, individual shatter cone is a curved, oblate branch that bifurcates from its parent fracture (e.g., a larger shatter cone) and expands to form a spoon‐like surface. The unique shatter cone striations are arranged in V‐shaped pairs whose enclosed angle is constant for a given sample. We propose that shatter cones are the natural consequence of tensile rock fracturing at extreme velocities. First, the structure of shatter cone networks is strikingly similar to the structure of branched networks of experimental dynamic fractures that propagate at high velocities (velocities that approach the Rayleigh wave speed, VR). Second, “fracture front waves,” generated experimentally by the interaction of a rapidly moving tensile fractures and material inclusions, create tracks on the fracture surface that correspond to the V‐shaped striations of shatter cones. Third, applying the front wave concept to our field measurements (Vredefort impact, South Africa) shows that the shatter cones propagated at velocities of 0.98–0.90VR, with a systematic velocity decrease from the impact center. These extreme asymptotic velocities require the intense energy flux of impacts. Our model explains all of the structural features of shatter cones (curved surfaces, cone directivity, unique striations, hierarchic, multilevel structure) and their exclusive occurrence at impact sites.
Warping and cracking of the Pacific plate by thermal contraction
Authors: Sandwell David , Fialko Yuri
Published: October 2004

Lineaments in the gravity field and associated chains of volcanic ridges are widespread on the Pacific plate but are not yet explained by plate tectonics. Recent studies have proposed that they are warps and cracks in the plate caused by uneven thermal contraction of the cooling lithosphere. We show that the large thermoelastic stress produced by top‐down cooling is optimally released by lithospheric flexure between regularly spaced parallel cracks. Both the crack spacing and approximate gravity amplitude are predicted by elastic plate theory and variational principle. Cracks along the troughs of the gravity lineaments provide conduits for the generation of volcanic ridges in agreement with new observations from satellite‐derived gravity. Our model suggests that gravity lineaments are a natural consequence of lithospheric cooling so that convective rolls or mantle plumes are not required.
Estimation of the thin ice thickness and heat flux for the Chukchi Sea Alaskan coast polynya from Special Sensor Microwave/Imager data, 1990–2001
Authors: Martin Seelye , Drucker Robert , Kwok Ronald , Holt Benjamin
Published: October 2004

One of the largest Arctic polynyas occurs along the Alaskan coast of the Chukchi Sea between Cape Lisburne and Point Barrow. For this polynya, a new thin ice thickness algorithm is described that uses the ratio of the vertically and horizontally polarized Special Sensor Microwave/Imager (SSM/I) 37‐GHz channels to retrieve the distribution of thicknesses and heat fluxes at a 25‐km resolution. Comparison with clear‐sky advanced very high resolution radiometer data shows that the SSM/I thicknesses and heat fluxes are valid for ice thicknesses less than 10–20 cm, and comparison with several synthetic aperture radar (SAR) images shows that the 10‐cm ice SSM/I ice thickness contour approximately follows the SAR polynya edge. For the twelve winters of 1990–2001, the ice thicknesses and heat fluxes within the polynya are estimated from daily SSM/I data, then compared with field data and with estimates from other investigations. The results show the following: First, our calculated heat losses are consistent with 2 years of over‐winter salinity and temperature field data. Second, comparison with other numerical and satellite estimates of the ice production shows that although our ice production per unit area is smaller, our polynya areas are larger, so that our ice production estimates are of the same order. Because our salinity forcing occurs over a larger area than in the other models, the oceanic response associated with our forcing will be modified.
A composite Mg II index spanning from 1978 to 2003
Authors: Viereck Rodney A. , Floyd Linton E. , Crane Patrick C. , Woods Thomas N. , Knapp Barry G. , Rottman Gary , Weber Mark , Puga Lawrence C. , DeLand Matthew T.
Published: October 2004

The Mg II core‐to‐wing ratio is a measure of solar chromospheric variability. The Mg II Index, formed by combining various Mg II core‐to‐wing data sets, has been used in EUV, UV, and total solar irradiance models. It is one of the longest records of solar variability reaching back nearly 25 years. We present a single, continuous time series of the Mg II core‐to‐wing ratio extending from November 1978 to the present. The Mg II core‐to‐wing ratio is a measurement that is well suited to the creating of a single time series despite the fact that the seven different instruments measuring the solar flux near 280 nm have different spectral resolutions and sample rates. The Upper Atmosphere Research Satellite (UARS) Solar Ultraviolet Spectral Irradiance Monitor (SUSIM), UARS Solar Stellar Irradiance Comparison Experiment (SOLSTICE), ERS‐2/Global Ozone Monitoring Experiment (GOME) and five NOAA solar backscatter ultraviolet data sets were used. Initially, the best data sets were selected to create a time series spanning from 1978 to the present. Then the gaps in the record were filled with data from various other Mg II data sets. Where no alternate data were available, a cubic spline function was used to bridge the missing data. In some cases the data gaps were too long for reasonable spline fits (more than 5 days), and for these gaps the F10.7 cm flux data were scaled to fill the gaps. Thus a continuous, uninterrupted time series of the Mg II core‐to‐wing ratio was created. The final Mg II time series is compared with other solar activity indices, such as the F10.7, He I 1083, and Sunspot number, to look for trends in the Mg II data.
Understanding midlatitude space weather: Storm impacts observed at Bear Lake Observatory on 31 March 2001
Authors: Sojka J. J. , Rice D. , Eccles J. V. , Berkey F. T. , Kintner P. , Denig W.
Published: October 2004

On 30 March 2001 in the late evening an auroral display was observed over the United States of America. The Bear Lake Observatory (BLO) magnetometer in Utah measured changes of 550 nT in less than 30 min. During the same period, BLO ionosonde measurements showed deep high‐frequency radio wave absorption up to 7 MHz. BLO's GPS single‐frequency receiver experienced geolocation errors of 20 m for over 3 hours. These storm signatures were also accompanied by L‐band scintillation effects which approached an S4 value of 0.2, which is large for midlatitudes. Although such measurements have been have been made at midlatitude locations for many decades, our knowledge of the processes and couplings involved in such events remains incomplete and, at best, qualitative. The interpretation of key ionospheric parameters' storm response is discussed in the context of present‐day auroral and geospace electrodynamics understanding. We find that at BLO (L = 2.38) the available data raise more questions and can provide almost no answers without observational inputs from other locations. One solution to this impasse is to field a ground‐based sensor network to resolve the spatial scales of the geospace electrodynamics. On the basis of the instrument complement at BLO, we argue for a contiguous U.S. deployment of modest magnetic/optical/RF observatories to observe the next solar maximum period's geomagnetic storms and to use these data to explore the physical processes and couplings on space weather effective scales in assimilative models in conjunction with space‐based observations.
Genotype by environment studies across Australia reveal the importance of phenology for chickpea (Cicer arietinum L.) improvement
Authors: Berger J. D. , Turner N. C. , Siddique K. H. M. , Knights E. J. , Brinsmead R. B. , Mock I. , Edmondson C. , Khan T. N.
Published: October 2004

Chickpea (Cicer arietinum L.) genotypes comprising released cultivars, advanced breeding lines, and landraces of Australian, Mediterranean basin, Indian, and Ethiopian origin were evaluated at 5 representative sites (Merredin, WA; Minnipa, SA; Walpeup, Vic.; Tamworth, NSW; Warwick, Qld) over 2 years. Data on plant stand, early vigour, phenology, productivity, and yield components were collected at each site.
Site yields ranged from 0.3 t/ha at Minnipa in 1999 to 3.5 t/ha at Warwick in 1999. Genotype by environment (G × E) interaction was highly significant. Principal components analysis revealed contrasting genotype interaction behaviour at dry, low-yielding sites (Minnipa 1999, Merredin 2000) and higher rainfall, longer growing-season environments (Tamworth 2000). Genotype clusters performing well under stress tended to yield well at all sites except Tamworth in 2000, and were characterised by early phenology and high harvest index, but were not different in terms of biomass or early vigour. Some of these traits were strongly influenced by germplasm origin. The material with earliest phenology came from Ethiopia, and southern and central India, with progressively later material from northern India and Australia, and finally the Mediterranean. There was a delay between the onset of flowering and podding at all sites, which was related to average temperatures immediately post-anthesis (r = –0.81), and therefore larger in early flowering material (>30 days at some sites). Harvest index was highest in Indian and Ethiopian germplasm, whereas crop height was greatest in Australian and Mediterranean accessions. Some consistently high yielding genotypes new to the Australian breeding program were identified (ICCV 10, BG 362), and the existing cultivar Lasseter was also confirmed to be very productive.
EST analysis of the heading leaf of Chinese cabbage (Brassica rapaL. ssp.pekinensis) in the early phase of the heading stage
Authors: Rui-Juan Gao , Da-Peng Dai , Rong-Cai Ma , Ming-Qing Cao , Yue-Ming Yan , Ya-Dong Wang , Shi-Jun Ren , Xin-Yu Guo
Published: October 2004

A cDNA library was constructed from the heading leaf in the early phase of the heading stage of Chinese cabbage (Brassica rapaL. ssp.pekinensis). By sequencing the randomly selected clones, 1363 sequences longer than 200 bp were found, with better trace data. After removing the poly(A) and contamination sequences, 1162 ESTs longer than 150 bp were obtained, of which 1102 shared significant similarity with known sequences in protein and nucleotide databases of the National Center for Biotechnology Information (NCBI) as revealed by searches using the BLASTX and BLASTN engines. Functional assignment of the ESTs was based on the method used in theArabidopsis thalianagenome-sequencing project. About 77% of the putative protein sequences with known biological functions best matched with those ofA. thalianadeposited in the non-redundant database of NCBI. These data suggest that Chinese cabbage is closely related toA. thaliana. This result is different from that reported in otherBrassicaspecies. At nucleotide level, however, 51% of the ESTs were homologous to those deposited forA. thalianawhen all ESTs were searched against the est-others database. In addition, 60 ESTs had no homology with any of the plant gene sequences deposited in GenBank. These ESTs are very important for understanding the unique developmental process of Chinesecabbage and elaborating its genetic mapping. Among the genes with assigned functions, the most abundant representatives were those involved in protein synthesis and energy metabolism. With the 1162 ESTs, 895 non-redundant contigs were generated after being aligned using the Seqman II module of DNAStar software at the threshold of more than 80% homology over a minimum of 40 base pairs. Of these, 723 were singletons containing only one EST sequence, indicating that many kinds of such genes are expressed in the heading leaf of Chinese cabbage. An expression profile of Chinese cabbage heading leaf with the 1162 ESTs was therefore acquired in this work. This could be very useful for uncovering the mechanism of the heading process, which is the most obvious characteristic of Chinese cabbage and perhaps other related species, such asBrassica oleracea. This work could accelerate the finding and characterization of genes specifically expressed in the heading stage of Chinese cabbage.
Study on tobacco disease resistances mediated by the elicitor gene cryptogein from Phytophthora cryptogea
Authors: Donghua Jiang , Zejian Guo , Xujun Chen , Zhiqiang Cheng , Zhong Zheng
Published: October 2004

The cryptogein (Crypt) gene was obtained by PCR amplification of genomic DNA from Phytophthora cryptogea and confirmed by DNA sequencing. A promoter of the rice phenylalanine ammonia-lyase (PAL) gene was used to regulate the expression of Crypt, because this promoter has a low level of constitutive expression, is strongly induced by pathogen infection and is expressed in epidermal tissues. These promoter characteristics may be suitable for potential inhibition of pathogen attack on epidermal tissues. For functional interaction of Crypt with its outer plasma membrane binding sites, Crypt was led by a signal sequence of the extracellular pathogenesis-related protein (PR1b) of tobacco (Nicotiana tabacum). The fused gene was constructed into a binary vector and the final plasmid (CHF-PAL::Crypt) was transformed into tobacco using the Agrobacterium-mediated transformation method. Twenty-two lines of transformants were obtained from selection medium containing 100 mg/l of kanamycin. Results from PCR amplification and Southern blot analysis demonstrated that Crypt was integrated into the tobacco genome. In the assay of pathogen challenge, nearly two-thirds (68.2%) of the transgenic plants showed significantly enhanced resistance against black shank fungal (Phytophthora parasitica var. nicotianae), brown spot fungal (Alternaria alternata) and wild fire bacterial (Pseudomonas syringae pv. tabaci) diseases. This observation indicates that low-level constitutive expression of Crypt gene in tobacco could have potential use in generating broad-spectrum disease-resistant plants.
Isolation and transformation ofTrichoderma virideprotoplasts
Authors: Shi-Wang Liu , Zheng-Yi Wang , Ze-Jian Guo
Published: October 2004

The conditions for protoplast isolation and regeneration fromTrichoderma viridewere studied. Protoplasts were optimally isolated when mycelia ofT. viridethat had been cultured for 24 h were digested with 4 mg/ml Glucanex in phosphate buffer (pH 6.98) for 4 h at 30°C, resulting in a protoplast yield of 4.7×107cfu/mg. The maximum regeneration ratio (14.5%) was obtained in mycelia culture medium containing 0.3 mol/l KCl and 0.3 mol/l inositol. In addition, a plasmid pCSSNCC1 carrying a hygromycin resistance gene and an elicitor-producing gene was transformed intoT. virideprotoplasts, with an efficiency of 1–2 transformants/μg DNA. The hygromycin-resistant transformants were determined by PCR and the elicitor protein was detected by ELISA. The results indicate that the elicitor protein was expressed stably inT. viride.
Genetic analysis and molecular mapping of eui1 gene conferring elongated uppermost internode in the indica rice mutant Xieqingzao eB1
Authors: Hong-Li Ma , Shu-Biao Zhang , Qin Lu , Xuan-Jun Fang , Shu-Lan Yang , Ren-Cui Yang
Published: October 2004

The indica rice Xieqingzao eB1 (XQZ eB1), a mutant with an elongated uppermost internode, was produced by mutagenesis from elite maintainer line Xieqingzao B (XQZ B) using γ-radiation. Compared with the wild-type XQZ B, plant height and the length of the rice panicle neck, second internode and third internode from the panicle were elongated significantly in XQZ eB1. Genetic analysis indicated that the trait for uppermost internode elongation of XQZ eB1 is controlled by a single recessive gene eui1, which is allelic to that of IR50eui (derived from 76:4512). Further studies were carried out using the bulk segregated analysis approach. An F3 population, derived from the cross XQZ eB1×Aijiaonante, was used to map the mutant gene eui1. Two SSR makers, RM164 and AC9, were identified to link to eui1, their genetic distances to eui1 being 18.4 and 7.9 cM, respectively. The eui1 gene was also mapped to the long arm of chromosome 5 in this research.
Genetic diversity and relationships among Secale L. based on RAMP markers
Authors: Hai-Ying Shang , You-Liang Zheng , Yu-Ming Wei , Wei Wu , Ze-Hong Yan
Published: October 2004

Genetic diversity and relationships among 21 accessions of Secale L., including three species and 10 subspecies, were evaluated using RAMP markers. Forty-one out of 80 (50.5%) RAMP primers, which produced clear and polymorphic bands, were selected for PCR amplification of genomic DNA. A total of 446 bands were amplified from the 41 primers, and 428 of these bands (about 96%) were polymorphic. Three to 19 polymorphic bands could be amplified from each primer, with an average of 10.4 bands. The RAMP-based genetic similarity (GS) values among the 21 Secale accessions ranged from 0.266 to 0.658, with a mean of 0.449. A high level of genetic variation was found between or within the wild populations and the cultivars. Based on the GS matrix, a dendrogram was constructed using the unweighted pair group method with arithmetic average (UPGMA). All 21 accessions could be distinguished by RAMP markers. Clustering results showed that the genetic diversity of Secale based on RAMP markers was correlated with geographical distribution. Six rye cultivars, originating from Poland, Portugal, Mexico, Hungary, Armenia and Ukraine, were clustered into one group. The six countries are all located in the transitional region of broad-leaf forests between maritime and continental temperate zones, with narrow latitude span. In comparison, the other five cultivars from countries scattered over a region with large latitude span were distributed within different groups or subgroups. Genetic relationships based on RAMP markers had great deviation from the original taxonomy. Some subspecies of the same species were distributed within different groups, while some accessions of different species were closely clustered into one subgroup. These results suggest that RAMP markers could be an effective technique for detecting genetic diversity among Secale and give some useful information about its phylogenic relationships.
Growth and nodulation competitiveness of poly(3-hydroxybutyrate) metabolism mutants of Sinorhizobium meliloti and effects of exogenous biotin
Authors: Mei-Xue Dai , Zachertowska Alicja , Charles Trevor C. , Bo Wu , Xue-Liang Bai , Cheng-Gang Zhang , Qing-Sheng Ma
Published: October 2004

This paper has been retracted by Dai Mei-Xue
Construction of plant expression vector and analysis of herbicide resistance and salt tolerance of transgenic tobacco
Authors: Xian-Yan Wang , Xiao-Yi Shan , Ai-Fang Yang , Ju-Ren Zhang
Published: October 2004

The plant expression vector pCAMBIA1300-AtNHX1-als was constructed by inserting the herbicide resistance gene als of Arabidopsis thaliana into the plasmid pCAMBIA1300-AtNHX1, which contains the AtNHX1 gene encoding the Na+/H+ antiport from the vacuolar membrane of A. thaliana. Transgenic tobacco plants were obtained via Agrobacterium-mediated transformation. PCR and Southern blot assay indicated that genes als and AtNHX1 had been integrated into the genome of the transgenic plants. The herbicide resistance and salt tolerance of transgenic plants increased by about 1000-fold and by 1.5% NaCl concentration, respectively, compared with controls. Herbicide resistance of the T1 progeny was evaluated by spraying transgenic plants with different concentrations of Luhuanglong at the four-leaf stage. Controls gradually died under 100 mg/l Luhuanglong whereas 73% of the T1 plants still survived at 500 mg/l Luhuanglong. Thus the plant expression vector pCAMBIA1300-AtNHX1-als could be used to improve the herbicide resistance and salt tolerance of crops.
Characterization of genotypes and genetic relationships of cili (Rosa roxburghii) and its relatives using RAPD markers
Authors: Xiao-Peng Wen , Xiu-Xin Deng
Published: October 2004

Cili (Rosa roxburghii Tratt), characterized by containing the highest vitamin C content among fruits and showing attractive senescence-retarding and cancer-preventing effects, has gained widespread interest. RAPD markers were applied to identify the seven genotypes of cili and to evaluate the genetic relationships within cili, as well as among its relatives. Sixteen arbitrary primers screened from 154 were adopted to analyse polymorphism in RAPD profiles for the 15 samples. A total of 137 RAPD bands ranging in size from 480 bp to 3.3 kb were obtained, among which 95 were polymorphic, covering 69.3% of the total bands obtained; and an average of 8.6 bands/primer was scored. The genotypes of cili and seedless cili could be identified efficiently by 14 genotype-specific bands, which were obtained from the polymorphic primers OPB-11, OPAF-16 and OPW-02. Additionally, using the unweighted pair group method with arithmetic mean, a dendrogram showing genetic relationships among the 15 samples was constructed based on cluster analysis of genetic distance. The possible origin of seedless cili and multiple-corolla cili is also discussed.
History of the Journal of the American College of Toxicology
Authors: Christian Mildred S.
Published: October 2004

This companion article to the History of the American College of Toxicology also is written in celebration of the 25th Anniversary of the American College of Toxicology (ACT). It relates how the official journal of the College evolved from a privately owned publication, the Journal of Environmental Pathology and Toxicology (JEPT), into publications owned and managed by the College and its Board, for the first 17 years as the Journal of the American College of Toxicology (JACT) and currently as The International Journal of Toxicology (IJT). It relates how the first journal focused on toxicological studies, potential cancer causes and concerns associated with environmental contamination and chemical exposure safety issues. It tells how this journal was replaced by one more broadly based that addressed multiple industries and regulatory approaches, accepted previously unpublishable “no-effect” studies, so important in eliminating unwarranted animal use, and provided review articles, rather than only original research. It also described how the JACT evolved into an international journal finally recognized for its quality reviews and peer-reviewed research. Each of the three journals that represented the College is described, as well as interesting events associated with their development and publication, including the activities and contributions of the first four editors in chief, Drs. Myron A. Mehlman, Mildred S. Christian, Robert M. Diener and Harihara Mehendale.
Bioavailability and Risk Assessment of Orally Ingested Polycyclic Aromatic Hydrocarbons
Authors: Ramesh Aramandla , Walker Stormy A. , Hood Darryl B. , Guillén Maria D. , Schneider Klaus , Weyand Eric H.
Published: October 2004

Polycyclic aromatic hydrocarbons (PAHs) are a family of toxicants that are ubiquitous in the environment. These contaminants generate considerable interest, because some of them are highly carcinogenic in laboratory animals and have been implicated in breast, lung, and colon cancers in humans. These chemicals commonly enter the human body through inhalation of cigarette smoke or consumption of contaminated food. Of these two pathways, dietary intake of PAHs constitutes a major source of exposure in humans. Although many reviews and books on PAHs have been published, factors affecting the accumulation of PAHs in the diet, their absorption following ingestion, and strategies to assess risk from exposure to these hydrocarbons following ingestion have received much less attention. This review, therefore, focuses on concentrations of PAHs in widely consumed dietary ingredients along with gastrointestinal absorption rates in humans. Metabolism and bioavailability of PAHs in animal models and the processes, which influence the disposition of these chemicals, are discussed. The utilitarian value of structure and metabolism in predicting PAH toxicity and carcinogenesis is also emphasized. Finally, based on intake, disposition, and tumorigenesis data, the exposure risk to PAHs from diet, and contaminated soil is presented. This information is expected to provide a framework for refinements in risk assessment of PAHs from a multimedia exposure perspective.
Contamination Is a Frequent Confounding Factor in Toxicology Studies with Anthraquinone and Related Compounds
Authors: Butterworth Byron E. , Mathre Owen B. , Ballinger Kenneth E. , Adalsteinsson Orn
Published: October 2004

Anthraquinone (AQ) (9,10-anthracenedione) is an important compound in commerce. Many structurally related AQ derivatives are medicinal natural plant products. Examples include 1-hydroxyanthraquinone (1-OH-AQ) and 2-hydroxyanthraquinone (2-OH-AQ), which are also metabolites of AQ. Some commercial AQ is produced by the oxidation of anthracene (AQ-OX). In the recent past, the anthracene used was distilled from coal tar and different lots of derived AQ often contained polycyclic aromatic hydrocarbon contaminants, particularly 9-nitroanthracene (9-NA). Many toxicology studies on AQ used contaminated anthracene-derived AQ-OX, including a National Toxicology Program (NTP) 2-year cancer bioassay that reported a weak to modest increase in tumors in the kidney and bladder of male and female F344/N rats and in the livers of male and female B6C3F1 mice. The AQ-OX used in that bioassay was mutagenic and contained 9-NA and other contaminants. In contrast, purified AQ is not genotoxic. The purpose of this paper is to provide additional information to help iterpret the NTP cancer bioassay. This paper describes a quantitative analytical study of the NTP anthracene-derived AQ-OX test material, and presents the results of mutagenicity studies with the 1-OH-AQ and 2-OH-AQ metabolites and the primary contaminant 9-NA. Purified 1-OH-AQ and 2-OH-AQ exhibited only weak mutagenic activity in selected strains of tester bacteria and required S9. Literature reports of potent mutagenic activity for 1-OH-AQ and 2-OH-AQ in bacteria minus S9 are, once again, very likely the result of the presence of contaminants in the test samples. Weak activity and limited production of the 1-OH-AQ and 2-OH-AQ metabolites are possible reasons that AQ fails to exhibit activity in numerous genotoxicity assays. 9-NA was mutagenic in tester strains TA98 and TA100 minus S9. This pattern of activity is consistent with that seen with the contaminated AQ-OX used in the NTP bioassay. Analysis of all the mutagenicity and analytical data, however, indicates that the mutagenic contamination in the NTP bioassay probably resides with compounds in addition to 9-NA. 9-NA exhibited potent mutagenic activity in the L5178Y mammalian cell mutagenicity assay in the presence of S9. The positive response was primarily associated with an increase in small colony mutants suggesting a predominance of a clastogenic mechanism. Quantitative mutagenicity and carcinogenicity potency estimates indicate that it is plausible that the contaminants alone in the NTP AQ-OX bioassay could have been responsible for all of the observed carcinogenic activity. Although AQ-OX is no longer commercially used in the United States, many of the reported genotoxicity and carcinogenicity results in the literature for AQ and AQ derivative compounds must be viewed with caution.
Secondary Ultraweak Luminescence from Humic Acids Induced by γ-Radiation
Authors: Gorączko Wieslaw , Sławiński Janusz
Published: October 2004

Humic substances (HSs) are products of biochemical transformations of plant and animal residues that make up a major fraction of the organic carbon of soil and aquatic systems in the environment. Because radioisotopes occur in the Earth's crust and because the entire biosphere is continuously exposed to cosmic radiation, ionizing radiation continually interacts with HSs. This chronic irradiation could have a significant ecological impact. However, very few publications are available that address possible consequences of chronic exposure of HSs to ionizing radiation from terrestrial and cosmic sources. This study was conducted to investigate possible impacts of exposure of HSs to ionizing radiation.

Dried humic acid (HA) or its associated aqueous solution (in 0.1 M Na2CO3) were exposed to absorbed γ-radiation in high doses of 1–90 kGy using a 60Co source. Following the γ-ray exposures, a secondary, ultraweak radiation emanation with wavelengths in the spectral range λ = 340–650 nm was recorded as a long-lived chemiluminescence (CL) from the aqueous solutions; however, the CL was not observed after irradiating dry HA.

Absorption spectra (for λ = 240–800 nm) of irradiated solutions indicated that polymerization/degradation processes were operating on the HA macromolecules. The effect of specific CL enhancers (luminol and lucigenin) on the intensity and kinetics of the CL implicated the participation of reactive oxygen species and free radicals in the CL and polymerization/degradation processes. For the range of absorbed doses used (1–10 kGy), the intensity of the induced CL was nonlinearly related to dose, suggesting that complex radical formation mechanisms were involved.
Radiation-Induced Change in Lymphocyte Proliferation and its Neuroendocrine Regulation: Dose-Response Relationship and Pathophysiological Implications
Authors: Liu Shu-Zheng
Published: October 2004

Cellular activities are regulated by intracellular signals initiated by stimulation from the external and internal environments. Different signal pathways are involved in the initiation of different cellular functions. In connection with cell proliferation in response to mitogenic stimulation, the dose-effect relationship of the magnitude of H-TdR incorporation into lymphocytes after exposure to different concentrations of concanavalin A (Con A) showed an inverted U-shaped curve in the concentration range 2–30 μg/ml. In previous studies it has been observed that the stimulatory effect of Con A (5 μg/ml) on lymphocyte proliferation was potentiated by whole-body irradiation (WBI) with low dose (0.075 Gy) and suppressed by WBI with high dose (2 Gy). When different concentrations of corticosterone, ranging from 10−12 to 10−7 M, were added to the Con A-stimulated lymphocytes, low-concentration stimulation and high-concentration suppression of lymphocyte proliferation were demonstrated. In the presence of 5 × 10−12 M (subphysiological concentration) of corticosterone the proliferation of thymocytes and splenic T cells in response to Con A was further up-regulated after low-dose radiation. Low-dose radiation (0.075 Gy) caused lowering of serum ACTH and corticosterone concentration as well as down-regulated transcription of the hypothalamic proopiomelanocortin gene. The present paper intends to show that multiple neurohormonal factors, including the pineal gland and neurotransmitters, in addition to the hypothalamic-pituitary-adrenocortical axis, are involved in the stimulation of immune responses induced by low-dose ionizing radiation. The complex nature of the interrelationship between the intracellular signaling of lymphocytes and the neuroendocrine regulation after WBI is discussed.