bluuebunny/crossref_metadata_2025 huggingface dataset:
Lithostratigraphy and chemostratigraphy of the Mesoproterozoic Sibley Group, northwestern Ontario, Canada
Authors: Rogala Becky , Fralick Philip W , Heaman Larry M , Metsaranta Riku
Published: September 2007

The 950 m thick Sibley Group is a relatively flat-lying assemblage of siliciclastic and chemical sedimentary rocks exposed from the northwest shore of Lake Superior to the Lake Nipigon region of Ontario. Remnants of the Sibley Group occur in an ovoid area that sagged at ~1.5 Ga, creating accommodation space for braided fluvial sediments, derived as either first or multicycle detritus from the Trans-Hudson Orogen. This was followed by a transgressive episode and deposition of lacustrine siliciclastics and evaporites. An influx of sediment from the south occurred immediately prior to final contraction of the lacustrine system and deposition of strandline, stromatolite-bearing carbonates. The change in paleoslope was accompanied by development of a north–south-oriented half-graben. Overlying subaerial deposits represent deposition on a sabkha or saline mud flat. This assemblage is abruptly succeeded upward by flooding of the basin and major deltaic progradation and capped by a delta-top fluvial system with extensive preservation of floodplain deposits. The majority of the deltaic sediment was derived from Proterozoic sources to the south. An unconformity separates this assemblage from a thick succession of sandstone deposited as an aeolian dune field, with detritus probably coming from as far as the New Quebec Orogen to Baltica region. The geochemistry of medium-grained sandstone denotes that sediment became more mature and quartz-rich upsection and that the source areas evolved to more felsic and less alkalic compositions. Paleomagnetically correlated units in the Belt Supergroup, Apache Group, and Troy Quartzite in western North America indicate that the broad climatic fluctuations recorded in the Sibley Group may represent continent-wide events.
Use of fluorescence in situ hybridization as a tool for introgression analysis and chromosome identification in coffee (Coffea arabica L.)
Authors: Herrera Juan Carlos , D’Hont Angelique , Lashermes Philippe
Published: September 2007

Fluorescence in situ hybridization (FISH) was used to study the presence of alien chromatin in interspecific hybrids and one introgressed line (S.288) derived from crosses between the cultivated species Coffea arabica and the diploid relatives C. canephora and C. liberica. In situ hybridization using genomic DNA from C. canephora and C. arabica as probes showed elevated cross hybridization along the hybrid genome, confirming the weak differentiation between parental genomes. According to our genomic in situ hybridization (GISH) data, the observed genomic resemblance between the modern C. canephora genome (C) and the C. canephora–derived subgenome of C. arabica (Ca) appears rather considerable. Poor discrimination between C and Ca chromosomes supports the idea of low structural modifications of both genomes since the C. arabica speciation, at least in the frequency and distribution of repetitive sequences. GISH was also used to identify alien chromatin segments on chromosome spreads of a C. liberica–introgressed line of C. arabica. Further, use of GISH together with BAC-FISH analysis gave us additional valuable information about the physical localization of the C. liberica fragments carrying the SH3 factor involved in resistance to the coffee leaf rust. Overall, our results illustrate that FISH analysis is a complementary tool for molecular cytogenetic studies in coffee, providing rapid localization of either specific chromosomes or alien chromatin in introgressed genotypes derived from diploid species displaying substantial genomic differentiation from C. arabica.
Quantitative trait locus analysis of multiple agronomic traits in the model legumeLotus japonicus
Authors: Gondo Takahiro , Sato Shusei , Okumura Kenji , Tabata Satoshi , Akashi Ryo , Isobe Sachiko
Published: September 2007

The first quantitative trait locus (QTL) analysis of multiple agronomic traits in the model legume Lotus japonicus was performed with a population of recombinant inbred lines derived from Miyakojima MG-20 × Gifu B-129. Thirteen agronomic traits were evaluated in 2004 and 2005: traits of vegetative parts (plant height, stem thickness, leaf length, leaf width, plant regrowth, plant shape, and stem color), flowering traits (flowering time and degree), and pod and seed traits (pod length, pod width, seeds per pod, and seed mass). A total of 40 QTLs were detected that explained 5%–69% of total variation. The QTL that explained the most variation was that for stem color, which was detected in the same region of chromosome 2 in both years. Some QTLs were colocated, especially those for pod and seed traits. Seed mass QTLs were located at 5 locations that mapped to the corresponding genomic positions of equivalent QTLs in soybean, pea, chickpea, and mung bean. This study provides fundamental information for breeding of agronomically important legume crops.
Sex-specific death in the Asian corn borer moth (Ostrinia furnacalis) infected withWolbachiaoccurs across larval development
Authors: Sakamoto Hironori , Kageyama Daisuke , Hoshizaki Sugihiko , Ishikawa Yukio
Published: September 2007

Maternally inherited endosymbiotic bacteria of the genus Wolbachia induce various kinds of reproductive alterations in their arthropod hosts. In a Wolbachia-infected strain of the adzuki bean borer moth, Ostrinia scapulalis (Lepidoptera: Crambidae), males selectively die during larval development, while females selectively die when Wolbachia are eliminated by antibiotic treatment. We found that naturally occurring Wolbachia in the congener O. furnacalis caused sex-specific lethality similar to that in O. scapulalis. Cytogenetic analyses throughout the entire larval development clarified that the death of males (when infected) and females (when cured) took place mainly during early larval stages. However, some individuals also died after complete formation of larval bodies but before egg hatching, or at late larval stages, even in the penultimate instar. Although the specific timing was highly variable, death of males and females occurred before pupation without exception. The potential association of sex-specific lethality with the sex determination mechanism was also examined and is discussed.
A surprising abundance of human disease genes in a simple “basal” animal, the starlet sea anemone (Nematostella vectensis)
Authors: Sullivan James C. , Finnerty John R.
Published: September 2007

Invertebrate animals have provided important insights into the mechanisms of, and treatment for, numerous human diseases. A surprisingly high proportion of genes underlying human disease are present in the genome of a simple, evolutionarily basal invertebrate animal, Nematostella vectensis , including some genes that are absent in established invertebrate model organisms. This, together with the laboratory tractability and regenerative capability of N. vectensis, recommends the species as an important new experimental model for the study of genes underlying human disease.
Analysis of genetic variation within clonal lineages of grape phylloxera (Daktulosphaira vitifoliae Fitch) using AFLP fingerprinting and DNA sequencing
Authors: Vorwerk S. , Forneck A.
Published: September 2007

Two AFLP fingerprinting methods were employed to estimate the potential of AFLP fingerprints for the detection of genetic diversity within single founder lineages of grape phylloxera ( Daktulosphaira vitifoliae Fitch). Eight clonal lineages, reared under controlled conditions in a greenhouse and reproducing asexually throughout a minimum of 15 generations, were monitored and mutations were scored as polymorphisms between the founder individual and individuals of succeeding generations. Genetic variation was detected within all lineages, from early generations on. Six to 15 polymorphic loci (from a total of 141 loci) were detected within the lineages, making up 4.3% of the total amount of genetic variation. The presence of contaminating extra-genomic sequences (e.g., viral material, bacteria, or ingested chloroplast DNA) was excluded as a source of intraclonal variation. Sequencing of 37 selected polymorphic bands confirmed their origin in mostly noncoding regions of the grape phylloxera genome. AFLP techniques were revealed to be powerful for the identification of reproducible banding patterns within clonal lineages.
Evolution and function of B chromosome 45S rDNA sequences inBrachycome dichromosomatica
Authors: Marschner Sylvia , Meister Armin , Blattner Frank R. , Houben Andreas
Published: September 2007

The origin and activity of 45S rDNA located on micro B chromosomes of the daisy Brachycome dichromosomatica were analysed. The internal transcribed spacer 2 (ITS2) of the 45S rRNA gene was sequenced for micro B, large B, and A chromosomes of B. dichromosomatica cytodeme A2, and conserved differences were identified between sequences originating from A and both types of B chromosomes. Phylogenetic analysis did not identify a species containing an ITS2 sequence more similar to either of the B chromosome sequences than the B. dichromosomatica A chromosome sequences. Thus, an origin of the B chromosomes from A chromosomes at a time prior to the divergence of the 4 cytodemes of B. dichromosomatica is suggested. The frequent (70%) nucleolar non-association of micro B chromosomes suggests inactivity of micro B 45S rDNA.
Assessing the putative roles of X–autosome and X–Y interactions in hybrid male sterility of theDrosophila bipectinataspecies complex
Authors: Mishra Paras Kumar , Singh Bashisth Narayan
Published: September 2007

Interspecific F1hybrid males of the Drosophila bipectinata species complex are sterile, while females are fertile, following Haldane’s rule. A backcross scheme involving a single recessive visible marker on the X chromosome has been used to assess the putative roles of X–autosome and X–Y interactions in hybrid male sterility in the D. bipectinata species complex. The results suggest that X–Y interactions are playing the major role in hybrid male sterility in the crosses D. bipectinata × D. parabipectinata and D. bipectinata × D. pseudoananassae , while X–autosome interactions are largely involved in hybrid male sterility in the crosses D. malerkotliana × D. bipectinata and D. malerkotliana × D. parabipectinata. However, by using this single marker it is not possible to rule out the involvement of autosome–autosome interactions in hybrid male sterility. These findings also lend further support to the phylogenetic relationships among 4 species of the D. bipectinata complex.
Organellar genome analysis of rye (Secale cereale) representing diverse geographic regions
Authors: Isik Z. , Parmaksiz I. , Coruh C. , Geylan-Su Y.S. , Cebeci O. , Beecher B. , Budak H.
Published: September 2007

Rye (Secale cereale) is an important diploid (2n = 14, RR) crop species of the Triticeae and a better understanding of its organellar genome variation can aid in its improvement. Previous genetic analyses of rye focused on the nuclear genome. In the present study, the objective was to investigate the organellar genome diversity and relationships of 96 accessions representing diverse geographic regions using chloroplast (cp) and mitochondrial (mt) DNA PCR-RFLPs. Seven cpDNA and 4 mtDNA coding and noncoding regions were amplified using universal cpDNA and mtDNA primer pairs. Each amplified fragment was digested with 13 different restriction enzymes. mtDNA analysis indicated that the number of polymorphic loci (20) was low and genetic differentiation (GST) was 0.60, excluding the outgroups (hexaploid wheat, Triticum aestivum, 2n = 6x = 42, AABBDD; triticale, ×Triticosecale Wittmack, 2n = 6x = 42, AABBRR). cpDNA analysis revealed a low level of polymorphism (40%) among the accessions, and GSTwas 0.39. Of the 96 genotypes studied, 70 could not be differentiated using cpDNA PCR-RFLPs even though they are from different geographic regions. This is most likely due to germplasm exchange, indicating that genotypes might have a common genetic background. Two cpDNA and 3 mtDNA fragments were significantly correlated to the site of germplasm collection. However, there was no clear trend. These results indicate that the level of organellar polymorphism is low among the cultivated rye genotypes. The cpDNA and mtDNA PCR-RFLP markers used in the present study could be used as molecular markers in rye genetics and breeding programs.
Genetic analysis and molecular mapping of a nuclear recessive male sterility gene,ms91(t), in rice
Authors: Liu Xia , Wang Songwen , Wang Yong , Wei Shu
Published: September 2007

Mutations that result in plant male sterility provide means not only to probe reproductive development but also to facilitate commercial heterosis application and hybrid seed production. In this study, we report a novel male sterility gene, ms91(t), in a spontaneous mutant line (SH38) from a Chinese rice cultivar (Oryza sativa subsp. japonica ‘Jijing14’). The sterility of SH38 was studied by examining its progenies derived from crosses with 6 japonica cultivars. Corresponding F2populations were obtained by selfing each of the 6 F1s and a backcross population was produced by crossing SH38 to the F1of SH38 × C18. Our results revealed that SH38 has normal agronomic traits but produces no pollen grains. Segregations of male-sterile and male-fertile progenies in the F2and backcross populations fit well with ratios of 3:1 and 1:1, respectively, indicating that ms91(t) is a single recessive gene. Amplified fragment length polymorphism (AFLP) analysis of SH38 and Jijing14 plants showed the presence of a unique band in SH38. Simple sequence repeat (SSR) analysis of the bulked and individual progenies of the F2population of SH38 × C18 showed linkage of ms91(t) with the SSR marker RM5853 on chromosome 1. Subsequently, ms91(t) was fine-mapped to the interval between markers RM7075 (3.75 cM) and RM5638 (3.57 cM). Our results would facilitate the isolation of ms91(t) and male sterility in heterosis application.
Chromosomal localization and molecular characterization of three different 5S ribosomal DNA clusters in the sea urchin Paracentrotus lividus
Authors: Caradonna Fabio , Bellavia Daniele , Clemente Ann Maria , Sisino Giorgia , Barbieri Rainer
Published: September 2007

In this paper the chromosomal localization and molecular cloning and characterization of three 5S rDNA clusters of 700 bp (base pairs), 900 bp, and 950 bp in the sea urchin Paracentrotus lividus are reported. Southern blot hybridization demonstrated the existence of three 5S rDNA repeats of differing length in the P. lividus genome. Fluorescence in situ hybridization analysis, performed in parallel on both haploid and diploid metaphases and interphase nuclei using different 5S rDNA units as probes, localized these 5S rDNA clusters in 3 different pairs of P. lividus chromosomes. This is the first complete gene mapping not only in a sea urchin but also in the phylum of echinoderms as a whole.
Identification of a sex-specific SCAR marker in dioecious Pandanus fascicularis L. (Pandanaceae)
Authors: Vinod M.S. , Raghavan Prashanth S. , George Suja , Parida Ajay
Published: September 2007

Pandanus fascicularis L. is a dioecious plant native to South Asia with significant numbers in coastal areas. With the aim of distinguishing male genotypes from female genotypes early in the vegetative growth phase, the current study was initiated using molecular markers. Based on the principle of bulked segregant analysis, the sampled plants were separated into 2 bulks depending on their sex. Of the 89 random amplified polymorphic DNA and inter-simple sequence repeat markers used, one decamer (OPO-08) consistently amplified a 1263 bp band in the males that was absent in the females. Its DNA sequence did not exhibit significant similarity to previously characterized sequences, but the presence of mononucleotide and dinucleotide repeats suggested that it was a repeat-rich region. A sequence-characterized amplified region marker (MSSRF-01) designed for this fragment continued to amplify the specific allele in all the male plants. Southern hybridization performed using the sex-specific fragment as a probe yielded results consistent with those previously obtained by polymerase chain reaction. These results strongly suggest that MSSRF-01 is a male-specific molecular marker. With no information available on the presence of sex chromosomes in Pandanus , this marker can be used to differentiate the sexes.
The roles of nitrogen dissimilation and assimilation in biological nitrogen removal treating low, mid, and high strength wastewater
Authors: Li Baikun , Irvin Shannon
Published: September 2007

Nitrogen dissimilation (nitrification and denitrification) and assimilation (uptake by cell growth) under different operational conditions (chemical oxygen demand (COD) and dissolved oxygen (DO)) were evaluated in a sequencing batch reactor (SBR) system. Nitrogen dissimilation played an important role for nitrogen removal at low to mid CODs, while nitrogen assimilation became more significant with biomass concentration steadily increasing at high COD. Specific denitrification rate increased at low to mid COD (C:N < 15), but decreased at high COD (C:N > 20). Both COD and C:N ratio should be kept in proper ranges to obtain sufficient biomass concentration for nitrogen assimilation in treatment systems. With alkalinity being consumed in nitrification and produced in denitrification, effluent alkalinity indicated the corresponding nitrogen concentrations under different COD loadings. ΔAlk between influent and effluent was also well correlated with assimilation and dissimilation. The discrepancy between ΔAlkTheory and ΔAlkExperi was less than 15 mg/L when dissimilation played a predominant role in nitrogen removal, while the discrepancy increased to 30 mg/L when assimilation became dominant.
Performance of a diatomite-based sorbent in removing mercury from aqueous and oil matrices
Authors: Wang Bo , Smith Timothy R.
Published: September 2007

Performance of diatomite based mercury sorbent (Chromosorb® QSR) powder and pellets was studied. Test results indicated that this sorbent was highly effective in removing various mercury species from aqueous and oil matrices. More than 99% removal was achieved after 30 min treatment with the diatomite sorbent powder at 1 g/L sorbent loading for an initial ionic mercury concentration of 9700 ppb. The diatomite sorbent was also stable when stored at oxidizing condition or at high temperature up to 200 °C. For continuous mercury removal process, the diatomite sorbent powder can be used as filter aid in pressure filters and the diatomite sorbent pellets can be used in fixed bed columns. A number of case studies presented on actual industrial wastewater and crude oil samples further indicate that this new mercury sorbent could provide a practical solution to mercury contamination problems in many industries.
Thermochemical oxidation of phenolic-laden liquid effluent models
Authors: Benali M. , Guy C.
Published: September 2007

The paper presents a novel atmospheric free-radical thermochemical oxidation (TCO) process in an aqueous phase for decontamination of industrial liquid effluents from organic toxic substances, in particular the refractory organic pollutants such as phenols. Its original concept is based on a direct contact between a contaminated liquid stream and the flame of a gas-fired burner containing free radicals such as OH·, H·, CH3·, and CHO·. Despite a direct contact of the contaminated liquid with the flame, the evaporation was less than 6% at the separator outlet where liquid temperatures ranged from 60 to 70 °C. A prototype of the 50 kW reactor operated in a continuous mode with the phenol concentration ranging from 200 to 20 000 mg/L was proven to process from 200 to 300 L/h of the contaminated model liquid. Experimental results show a final destruction efficiency of over 98%. Kinetics of phenol oxidation in TCO shows that the induction period can be avoided by injection of a small amount of hydrogen peroxide in the contaminated effluent feeding tank.
Decontamination of water polluted with oil through the use of tanned solid wastes
Authors: Gammoun Amal , Tahiri Soufiane , Albizane Abderrahman , Azzi Mohammed , de la Guardia Miguel
Published: September 2007

Sorption by natural organic substrates, inorganic materials or synthetic fibers is one of the most popular methods used for the separation of oily wastes from contaminated water. In this work, the ability of chrome shavings (CS) and of buffing dusts of crust leather (BDCL) to remove motor oils and oily wastes from demineralised water and natural seawater has been studied. Tannery solid wastes are formed mainly by proteins and have a highly organized structure in the form of fibers (ΦΦ: 100 nm). These wastes have a high oil sorption capacity. Tanned solid wastes are capable of absorbing many times their weight in oil (6.5–7.6 and 12.8–14.5 g/g dry substrate, respectively, for ground CS and BDCL). The sorption capacity depends strongly of sorbent nature. The removal of oils from the water surface is a quasi-instantaneous process. After use, the saturated waste floats and can be removed in an efficient and easy manner. The results look fairly promising as to possibilities of using tanned wastes to remove oils from industrial effluents and from contaminated coastal areas.
A review of the effectiveness of current time–temperature regulations on pathogen inactivation during composting
Authors: Wichuk Kristine M. , McCartney Daryl
Published: September 2007

Pathogenic organisms can be present in all types of compost feedstocks. Since the infective dose for many of these organisms is very low, it is generally accepted that pathogens should be reduced to non-detectable levels. According to North American regulatory bodies (United States Environmental Protection Agency and Canadian Council of Ministers of the Environment), pathogen inactivation is expected to occur if all particles of compost maintain temperatures greater than 55 °C for at least 3 days. A literature review was conducted to examine whether compliance with these time–temperature conditions consistently resulted in production of pathogen-free compost products. Survival of pathogenic bacteria, protozoa, and helminths occurred in a significant number of studies, despite the prescribed time–temperature conditions apparently being met. It was hypothesized that this could either be the result of inadequate time–temperature requirements or of difficulties in ensuring that the time–temperature criteria are met by all compost particles.
Neural network models of Cryptosporidium parvum inactivation by chlorine dioxide and ozone
Authors: Janes Kevin R. , Musilek Petr
Published: September 2007

Several neural network disinfection models for the inactivation of Cryptosporidium parvum by chlorine dioxide and ozone were developed and compared against existing temperature-corrected Chick-Watson models. In this study a back propagation based network-pruning algorithm called structural learning with forgetting has been used to train all neural network models. The neural network disinfection models performed well relative to the competing Chick-Watson models and learned several basic input variable trends established in earlier disinfection studies. Water temperature was found to be a significant process variable and pH less influential for all neural network models. The final disinfectant residual was included as an input variable to incorporate residual decay, and was found to be more relevant for disinfectants with less stable residuals.
Biological denitrification of reverse osmosis brine concentrates: I. Batch reactor and chemostat studies
Authors: Ersever Ilknur , Ravindran Varadarajan , Pirbazari Massoud
Published: September 2007

A major technological concern with reverse osmosis in water purification, wastewater treatment, and water reclamation or recycling is the production of brine concentrates high in ammonia or nitrogen. This project addresses biological denitrification of reverse osmosis brine concentrates in a bioactive fluidized bed adsorber reactor (FBAR), accomplished in four stages. The first three stages are described in this paper, while the final stage is addressed in the companion paper (Ersever et al. 2007). The first stage optimized an FBAR to produce nitrified brine for subsequent denitrification studies. The second stage employed batch reactors to evaluate denitrification parameters such as temperature, pH, total dissolved solids, and carbon-to-nitrogen ratio. The specific denitrification rate was maximum at a temperature of 35 °C, pH of 8.0, and carbon-to-nitrogen ratio of 1.8. The third stage involved chemostats to determine Monod parameters under nitrate-, nitrite-, and carbon-limiting conditions. A biokinetic model was employed to simulate chemostat dynamics and to estimate the biological parameters. The final stage entailed FBAR denitrification experiments under different hydraulic retention times, nitrate concentrations, and packing media; simultaneous denitrification and sulfate reduction were addressed. A second FBAR used in series with the first achieved an overall sulfate reduction of 99%, and a biofilter effectively removed the hydrogen sulfide generated.
Climatic change effects on the physiology and growth of Pinusponderosa: expectations from simulation modeling
Authors: Constable John V.H. , Taylor Jr. George E. , Laurence John A. , Weber James A.
Published: September 2007

The TREGRO model was used to simulate the growth response of mature Pinusponderosa Dougl. ex Laws. to the interacting effects of changes in CO2 (+200 μL/L), temperature (+4 °C), and O3 (0.5×, 1×, and 2×ambient). Relative to simulated growth under the base-line climate in Corvallis, Oregon, elevated CO2 and temperature individually increased total-tree biomass gain by 29% and 13%, respectively, but when combined increased biomass gain by 49%. Ozone at all exposures reduced total-tree biomass gain by 1%, 19%, and 39%, respectively, as compared with simulated base-line conditions. Elevated CO2 increased photosynthesis and reduced stomatal conductance and partially offset growth reductions due to 2× O3. Elevated temperature, however, increased both photosynthesis and stomatal conductance and was less effective at mitigating growth reductions due to 2× O3. Growth at 2× O3 in elevated CO2 and temperature conditions had little effect on total-tree growth, but decreased fine-root growth by 61%. The simulated changes in stomatal conductance and fine-root biomass are expected to interact with the availability of soil resources to affect tree growth and possibly alter the distribution of Pinusponderosa.
Contributions of fine root production and turnover to the carbon and nitrogen cycling in taiga forests of the Alaskan interior
Authors: Ruess R.W. , Cleve K. Van , Yarie J. , Viereck L.A.
Published: September 2007

Fine root production and turnover were studied in hardwood and coniferous taiga forests using three methods. (1) Using soil cores, fine root production ranged from 1574 ± 76 kg•ha−1•year−1 in the upland white spruce (Piceaglauca (Moench) Voss) stand to 4386 ± 322 kg•ha−1•year−1 in the floodplain balsam poplar (Populusbalsamifera L.) stand, accounting for 49% of total production for coniferous stands and 32% of total production for deciduous stands. Fine root turnover rates were higher in floodplain (0.90 ± 0.06 year−1) stands than in upland (0.42 ± 0.10 year−1) stands. Across all sites, the ratio of fine root turnover to litter fall averaged 2.2 for biomass and 2.8 for N. Both values were higher in floodplain stands than in upland stands, and in coniferous stands than in deciduous stands. (2) The C budget method showed that C allocation to fine roots varied from 150 to 425 g C•m−2•year−1 and suggested that soil respiration was more dependent on C derived from roots than from aboveground inputs. The C allocation ratio (C to roots: C to litter fall) was inversely correlated with litter-fall C and varied from 0.3 to 69.5; there was a tendency for higher proportional belowground allocation in coniferous stands than in deciduous stands and the highest levels were at the earliest successional sites. (3) Estimates of apparent N uptake (Nu), N allocation to fine roots, and fine root production based on N budget calculations showed that annual aboveground N increments exceeded Nu estimates at half the sites, indicating that the method failed to account for large amounts of N acquired by plants. This suggests that plant and (or) mycorrhizal uptake of soil organic N may be more significant to ecosystem N cycling than mineral N turnover by the soil microbial biomass.
Soil water leachate from two forested catchments on the Precambrian Shield, Ontario
Authors: LaZerte Bruce D. , Scott Lem
Published: September 2007

A predominantly coniferous catchment on the Precambrian Shield had significantly more acid, base-poor, and Al-rich soil solutions than a predominantly deciduous catchment. Eight-year median depth profiles of the forest floor solutions revealed that ceramic tension lysimeters collected significantly higher levels of Al and Si, lower amounts of NO3−, and equal amounts of dissolved organic carbon than plastic zero-tension lysimeters. There was no significant difference between lysimeter types in the deeper mineral soils. NO3−, NH4+, K+, organic C, organic Al, Fe, and to a lesser extent Ca2+ and Mg2+ were more abundant in forest floor solutions than in the mineral soils. Inorganic Al, F−, Na+, and SO42− were more abundant in the mineral horizons, and Cl− was uniform throughout the profile. Calculations based on the Na profile and the weathering of plagioclase feldspars suggested that secondary Al and Si minerals were accumulating in the mineral soil. Long-term median inorganic Al concentrations followed the microcrystalline gibbsite solubility curve (−log(Al3+) = −9.2 + 3.0(pH); R2 = 0.97), and F− was closely correlated (R2 = 0.7). NO3−, NH4+, and K+ in the forest floor exhibited the strongest seasonal patterns, with peaks during the winter–spring snowmelt and late summer. Their levels increased severalfold in response to summer drought, but there was little response in the lower horizons. Apparently because of a decline in SO42− and possibly Ca2+ deposition, there was a long-term decline in Ca2+ and SO42− in the stream draining the PCl mineral horizons (approximately −2.1 ± 0.4 μequiv.•L−1•year−1), and a similar Ca2+ decline in the mineral soil solutions themselves. However, there was no change in pH or inorganic Al levels.
Habitat and harvest scheduling using Bayesian statistical concepts
Authors: Van Deusen Paul C.
Published: September 2007

A procedure is derived to generate long-term management schedules of habitat and harvest on large land holdings. The method utilizes spatial distributions that are derived using Bayesian statistical concepts. Model-based methods are proposed for incorporating spatial constraints and stochastically creating habitat. Thus, the Bayesian scheduler treats the schedule as a stochastic process rather than a deterministic one and generates virtually an infinite number of potential schedules that share common distributional characteristics. These schedules can then be examined and chosen according to economic or other criteria.
Reductions in gas exchange of Populustremuloides caused by leaf aging and ozone exposure
Authors: Clark C. Scott , Lee E.H. , Weber J.A. , Hogsett W.E.
Published: September 2007

Declines in gas exchange of mature leaves of Populustremuloides Michx. (quaking aspen) seedlings under four O3 treatments were investigated in a 33-d study. Gas exchange fell gradually with time, but under O3 exposure declines were accelerated. Photosynthetic capacity, stomatal conductance, and carboxylation efficiency were highly correlated, suggesting a coordinated reduction in the physiological activity of stressed leaves. Intercellular CO2 was not significantly different among treatments, indicating that stomatal opening was not the primary factor in limiting photosynthesis. Analysis of A:Ci response curves revealed that stomatal limitation increased only slightly, while biochemical limitation more than doubled, reaching a maximum of 47.1% by the third week of fumigations. Number of surviving leaves, ratio of surviving leaves to leaves produced, and total leaf area declined with O3 exposure. Whole-plant response curves were less linear than curves for the oldest subset of leaves because new leaves were produced continuously during the study, resulting in within-plant variation in O3 exposure. Declines in photosynthesis were greater than leaf area losses when data were expressed as a percentage of the control treatment. These results indicate that exposure to O3 for a relatively short time severely limits plant carbon gain in a sensitive free-growing species like aspen.
Damage to residual trees from cable yarding when partial cutting second-growth stands in coastal British Columbia
Authors: Howard Andrew F.
Published: September 2007

Damage to residual trees associated with a specific combination of stand conditions, silvicultural treatment, and harvesting system must be known if this information is to guide foresters in the design of prescriptions for individual stands planned for partial cutting. A study was made of residual tree damage in two stands of second growth in coastal British Columbia that were partially cut and the timber was yarded with cable systems. Damage to residual trees was found to be high at both sites. The percentage of trees damaged decreased with increasing distance from the skyline corridor, and bigger trees were less likely to be damaged than small ones. Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) was shown to be the least susceptible to damage, followed by western hemlock (Tsugaheterophylla (Raf.) Sarg.) and finally western redcedar (Thujaplicata Donn ex D. Don). Wider spacing of skyline corridors is suggested as one means for reducing stand damage.
Effects of geographic information system vector–raster–vector data conversion on landscape indices
Authors: Bettinger Pete , Bradshaw Gay A. , Weaver George W.
Published: September 2007

The effects of geographic information system (GIS) data conversion on several polygon-and landscape-level indices were evaluated by using a GIS vegetation coverage from eastern Oregon, U.S.A. A vector–raster–vector conversion process was used to examine changes in GIS data. This process is widely used for data input (digital scanning of vector maps) and somewhat less widely used for data conversion (output of GIS data to specific formats). Most measures were sensitive to the grid cell size used in the conversion process. At the polygon level, using the conversion process with grid cell sizes of 3.05, 6.10, and 10 m produced relatively small changes to the original polygons in terms of ln(polygon area), ln(polygon perimeter), and 1/(fractal dimension). When grid cell size increased to 20 and 30 m, however, polygons were significantly different (p < 0.05) according to these polygon-level indices. At the landscape level, the number of polygons, polygon size coefficient of variation (CV), and edge density increased, while mean polygon size and an interspersion and juxtaposition index (IJI) decreased. The youngest and oldest age-class polygons followed the trends of overall landscape only in terms of number of polygons, mean polygon size, CV, and IJI. One major side effect of the conversion process was that many small polygons were produced in and around narrow areas of the original polygons. An alleviation process (referred to as the dissolving process) was used to dissolve the boundaries between similarly attributed polygons. When we used the dissolving process, the rate of change for landscape-level indices slowed; although the number of polygons and CV still increased with larger grid cell sizes, the increase was less than when the dissolving process was not used. Mean polygon size, edge density, and fractal dimension decreased after use of the dissolving process. Trends for the youngest and oldest age-class polygons were similar to those for the total landscape, except that IJI was greater for these age-classes than for the total landscape.
Foliar nutrient dynamics of 11-year-old loblolly pine (Pinustaeda) following nitrogen fertilization
Authors: Zhang Shangshan , Allen H. Lee
Published: September 2007

Foliar macronutrient (N, P, K, Ca, Mg) concentration, content, retranslocation, internal balance, and variation with crown location and foliage age were quantified in 11-year-old loblolly pine (Pinustaeda L.) trees grown in two soil nitrogen regimes. Concentrations of N, P, and K decreased with foliage age, while the concentration of Ca increased. Nutrient content of new foliage increased with the elongation of foliage. Estimates of retranslocation were 75%, 73%, 83%, 28%, and less than 5% for N, P, K, Mg, and Ca, respectively. Increases in nutrient content of new foliage were associated with decreases in nutrient content of old foliage, suggesting transfer of nutrients to developing foliage. Concentrations and contents of P and K were greatest in the upper crown. Differences in N concentration among crown locations were small, although N content increased in the upper portion of the crown. Calcium and Mg concentrations decreased with crown height, but their contents generally did not differ among crown locations. Nitrogen fertilization increased N and Ca concentrations and fascicle weight, decreased P and Mg concentrations, and had no significant effect on K concentration. For the purposes of determining nutrient deficiency, our results suggest that foliar samples should be collected from 1-year-old foliage in the midcrown position during the rapid growth period for new shoots.
Effects of laminated root rot (Phellinusweirii) on Douglas-fir foliar chemistry
Authors: Thomson A.J. , Goodenough D.G. , Barclay H.J. , Lee Y.J. , Sturrock R.N.
Published: September 2007

To determine the effects of laminated root rot (Phellinusweirii) on Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) foliar chemistry, chlorophyll a and b, N, P, K, Ca, Mg, Mn, Fe, and foliage moisture were measured in new and old foliage from 20- to 80-year-old coastal Douglas-fir. Measurements were made in June and September of 1993 and June of 1994. Chlorophyll a and b, Ca, Fe, Mg, and Mn were higher in old foliage in both June and September, while moisture, N, and K were higher in the new foliage. The relationship of P to foliage age changed with time. Reductions in foliage moisture, chlorophyll a, and N were consistently associated with P. weirii infection in all plots, but the normal high variability in foliage chemistry made demonstration of statistical significance difficult. Within-tree variability in foliar chemistry was much higher in June than in September, especially in the new foliage.
Impact of simulated acid rain on microbial respiration, biomass, and metabolic quotient in a mature sugar maple (Acersaccharum) forest floor
Authors: Thirukkumaran Chandini M. , Morrison Ian K.
Published: September 2007

Effects of simulated acid rain on forest floor microbiological processes were investigated in an old-growth sugar maple (Acersaccharum Marsh.) woods at Turkey Lakes Watershed, northern Ontario, Canada. Sulphate and NO3− in ambient precipitation received on four replicate plots were augmented with additions of dilute (0.02 N) H2SO4 and HNO3, applied alone and in combination periodically during the growing seasons of 1993 and 1994. The equivalent load of SO42− applied in the present experiment was ca. 6 times that in ambient precipitation in the H2SO4-only treatment and half that in the combined treatment over the study period. In situ soil respiration measured during the summer and fall of 1994 showed no adverse effects of acid treatment. In the laboratory, soil microbial respiration, biomass (as determined by substrate-induced respiration), and microbial biomass carbon: organic carbon (Cmic/Corg ratios were significantly depressed in the L or FH layers of the forest floor when H2SO4 was applied alone or in combination with HNO3. No effects of HNO3 were detected when applied alone. Microbial respiration, substrate-induced respiration, and Cmic/Corg ratios were significantly correlated with forest floor pH. Microbial metabolic quotients (respiration:biomass ratios) were not adversely affected by any of the treatments. The observed deleterious effects of H2SO4 application under experimental conditions suggest the possibility of adverse effects in the field over the long-term.
Genetic diversity and differentiation in populations of Japanese stone pine (Pinuspumila) in Japan
Authors: Tani Naoki , Tomaru Nobuhiro , Araki Masayuki , Ohba Kihachiro
Published: September 2007

Japanese stone pine (Pinuspumila Regel) is a dominant species characteristic of alpine zones of high mountains. Eighteen natural populations of P. pumila were studied in an effort to determine the extent and distribution of genetic diversity. The extent of genetic diversity within this species was high (HT = 0.271), and the genetic differentiation among populations was also high (GST = 0.170) compared with those of other conifers. In previous studies of P. pumila in Russia, the genetic variation within the species was also high, but the genetic differentiation among populations was low. We infer that this difference originates from differences in geographic distribution and ecological differences between the two countries. The genetic variation within each population tended, as a whole, to be smaller within marginal southern populations than within northern populations. Genetic relationships among populations reflect the geographic locations, as shown by unweighted pair-group method with arithmetic means and neighbor-joining phylogenetic trees.
Static tests of lodgepole pine stability in the central interior of British Columbia
Authors: Krasowski M.J. , Hawkins C.D.B. , Coates H. , Ott P.K.
Published: September 2007

Lodgepole pine (Pinuscontorta Dougl. ex Loud. var. latifolia Engelm.) static stability was examined on six central interior British Columbia forest sites using dynamometer testing. Stand ages ranged from 11 to 21 years. The same number of tests were done in each cardinal direction. Two forces were measured: (i) first sign of destabilization (root plate movement or a loud cracking sound); (ii) maximum force recorded during uprooting. Forces were converted to turning moments of destabilization (M1) and complete uprooting (M2). On one site, trees planted as bare-root stock were significantly more firm (M1) than those planted as Styroblock stock, but differences were insignificant on two other sites. There were no differences in M2 between these stock types. No differences were observed among chemically root-pruned planting stock and the two above stock types. On coarse, sandy soil, M1 and M2 were small. On the same site, trees on slopes were less stable (when pulled down slope) than those growing on flat terrain. Naturally regenerated trees in a dense unthinned stand had a smaller M1 than nearby planted trees. However, in a natural stand thinned 1 year before testing, M1 did not differ between naturals and planted stock. Trees germinated in peat blocks and planted before roots had incurred air pruning had significantly greater M1 values than comparable Styroblock stock, but M2 values were not different. Rather than stock type, soil properties and stocking density are likely the prime determiners of stand stability.
Trends in variances and heritabilities with stand development of tropical pines
Authors: Vásquez J. , Dvorak W.S.
Published: September 2007

Phenotypic and additive genetic variances as well as narrow-sense heritability for cumulative height were determined from assessments of tropical pine (Pinuscaribaea Morelet, Pinuschiapensis (Mart.) Andresen, and Pinustecunumanii (Schw.) Eguiluz et Perry) trials established in South America and South Africa by the Central America and Mexico Coniferous Resources (CAMCORE) Cooperative. Cumulative stem height was analyzed from 1-, 3-, 5-, and 8-year data collected on open-pollinated families to determine additive genetic and phenotypic variances. Variances based on arithmetic as well as log-transformed values are presented. Phenotypic and genetic variances of log-transformed values decreased over time, probably reflecting the onset of intergenotypic competition. Absolute variances increased over time as the trials became older, but the rate of increase for phenotypic variance was greater than that for additive variance. Individual narrow-sense heritabiiities changed over time but without showing any definite trend by species. It appeared that variance trends reflected the varying ontogenetic changes during the development of the stands, which could be indicated by size of the trees rather than by their age. Breeding strategies in tropical pines should consider the increasing intensity of environmental effects as a stand matures, since they cause a decline of genetic variances at a higher rate than phenotypic variances. Furthermore, it is hypothesized that a phenotypic trait at a given ontogenetic stage of the individual is under temporal control of a set of genes that changes as the temporal environmental conditions change.
Influence of adjacent stand on spatial patterns of soil carbon and nitrogen in Eucalyptus and Albizia plantations
Authors: Ewers Brent , Binkley Dan , Bashkin Michael
Published: September 2007

The chemistry and fertility of forest soils can be strongly influenced by tree species. Many studies have addressed the effects of monocultures on forest soil chemistry, but few have examined the effects of varying ratios of species within stands. In the absence of well-designed trials across a range of mixture ratios, we examined the spatial influence of adjacent stands on soil chemistry as a first approximation of the effect of mixed-species stands. We examined soil total carbon (C), nitrogen (N), and C/N along transects in adjacent, replicated, 12-year-old plantations of pure Eucalyptussaligna (Sm.) and pure N2-fixing Albiziafalcataria (L.) Fosberg. Soils from the center of the Eucalyptus stands had more C, less N, and higher C/N than soils from the center of the Albizia stands. The effects of the neighbor species were apparent for only about 5 m into the stands. This limited distance of the neighboring plot effect suggests that a species mixture ratio of 5:1 would be the highest ratio that would show any effect of the minor species on these soils.
Dynamique de la régénération d'une pessière à lichen dans la zone de la pessière noire à mousses, nord du Saguenay–Lac-Saint-Jean (Québec)
Authors: Riverin Stéphane , Gagnon Réjean
Published: September 2007

Regeneration dynamics have been studied in three open lichen–spruce woodlands located in the black spruce feather-moss forest zone. Black spruces (Piceamariana (Mill.) BSP) belonging to the adult stratum originated from a fire that occurred in 1877. Population history and ecology has been studied on the basis of the establishment period of individuals. The age of black spruces belonging to the regeneration stratum was calculated by using the cross-dating method. The establishment period of the seedlings was determined by the age structure. The black spruces of these open forests belong to two different populations. The adult population originated from the 1877 fire whereas the regeneration population seems to have established itself following another fire that occurred in 1922–1923. Black spruce seedlings of the regeneration stratum are very old (60 years-old on average) in spite of a low height (mean height of 96 cm). Although these open forests are under favourable climatic conditions, they have dynamics similar to lichen–spruce woodlands of the taiga zone. In the last 45 years, no seedlings have settled in these sparse forests.
SELF-ADJOINTNESS OF GENERALIZED MIC–KEPLER SYSTEM
Authors: GIRI PULAK RANJAN
Published: September 2007

We have studied the self-adjointness of generalized MIC–Kepler Hamiltonian, obtained from the formally self-adjoint generalized MIC–Kepler Hamiltonian. We have shown that for [Formula: see text], the system admits a one-parameter family of self-adjoint extensions and for [Formula: see text] but [Formula: see text], it also has a one-parameter family of self-adjoint extensions.