bluuebunny/crossref_metadata_2025 huggingface dataset:
Regional climatic drivers of synchronous zooplankton dynamics in north-temperate lakes
Authors: Rusak James A , Yan Norman D , Somers Keith M
Published: April 2008

The role that climate plays in determining the temporal dynamics of freshwater zooplankton is poorly understood, despite its potential to synchronize population dynamics on a regional basis. We quantify the spatial synchrony of common zooplankton taxa among lakes in the Dorset, Ontario, area and investigate the climatic mechanisms responsible for these patterns at both annual and seasonal scales. We show that the dynamics of several taxa are characterized by similar patterns of abundance among lakes across the region, suggesting a synchronising effect of climate on zooplankton population abundances. Using multiple regression analyses to compare zooplankton dynamics with climatic and in-lake variables, we find that El Niño – Southern Oscillation (ENSO) events and ice cover variability are among the most important predictors of synchrony at annual and seasonal scales, particularly for Leptodiaptomus and Bosmina. Leptodiaptomus, a dominant herbivore in these lakes, had decreased abundances in years with earlier ice-off dates and shorter periods of ice cover. Secchi depth was also synchronous and appeared to respond to regional meteorological factors (spring temperature and precipitation, ice duration). A warming climate with the ability to modify ice and ENSO dynamics, as well as temperature and precipitation patterns, may also alter the structure and dynamics of zooplankton communities in north-temperate lakes.
Swimming Behavior of Coho Salmon, Oncorhynchus kisutch, in the Open Sea as Determined by Ultrasonic Telemetry
Authors: Ogura Miki , Ishida Yukimasa
Published: April 2008

Four coho salmon, Oncorhynchus kisutch, with depth-sensing ultrasonic transmitters were tracked in the central North Pacific Ocean during June and early July 1989. The average swimming depths of the fish ranged from 7.1 to 13.4 m, and they spent 72.3–92.8% of the time in the upper 15 m of the water column; maximum depths were 53–74 m. Average ground speeds ranged from 0.29 to 0.40 m∙s−1. Although swimming depths during the day were deeper than at night, one coho salmon tracked for 5 d showed no regular daily patterns of horizontal or vertical movements.
Modèles empiriques de la production annuelle et du rapport P/B d'invertébrés benthiques d'eau courante
Authors: Morin Antoine , Bourassa Nathalie
Published: April 2008

Published data on secondary production of running water invertebrates are analyzed by multiple regression to quantify the relationship between productivity (P, in grams dry mass per square metre per year) and biomass (B, in grams dry mass per square metre), mean individual mass (M, in grams dry mass), and annual mean water temperature (T, in degrees Celsius) to compare productivity of major taxonomic groups and to compare to invertebrate populations from other aquatic ecosystems. The equation P = 0.18 B1.01M−0.34 100.037T explains 87% of the variability in log P in the 291 lotic invertebrate populations analyzed. Significant differences were detected among major taxonomic groups, but these differences account for only about 4% of the variability in log P. Once the effect of biomass, mean individual mass and water temperature are taken into account, productivity of lake and stream invertebrate populations is quite similar, although productivity is a linear function of biomass in streams and not in lakes. Comparison of models for running waters, lake and marine ecosystems suggests that marine invertebrates are less productive than freshwater populations.
Allochthonous versus Autochthonous Organic Matter Contributions to the Trophic Support of Fish Populations in Clear-Cut and Old-Growth Forested Streams
Authors: Bilby Robert E. , Bisson Peter A.
Published: April 2008

Annual organic matter inputs and production of stocked coho salmon (Oncorhynchus kisutch), coastal cutthroat trout (O. clarki clarki), and shorthead sculpin (Cottus confusus) from spring through early autumn were monitored for 2 yr in two headwater tributaries of the Deschutes River, Washington. One site was bordered by old-growth coniferous forest; the other was an area clear-cut without buffer strips 7 yr before the study. Allochthonous organic matter (terrestrial origin) dominated inputs to the old-growth site and contributed ~300 g∙m−2∙yr−1, while autochthonous organic matter totaled ~100 g∙m−2∙yr−1. In the clear-cut site, autochthonous inputs contributed ~175 g∙m−2∙yr−1, but allochthonous inputs contributed only ~60 g∙m−2∙yr−1 owing to loss of riparian vegetation. Although combined allochthonous and autochthonous inputs were almost twofold greater in the old-growth site, fish production was greater in the clear-cut site. Production of coho salmon and shorthead sculpin during early summer was largely responsible for differences between sites. Fish populations appeared to depend upon food derived from autotrophic pathways during spring and summer in the presence or absence of forest canopy, a hypothesis supported by analysis of coho stomach contents and the similar ratios of autochthonous inputs and fish production between the two streams.
Effects of Multiple Fires on Nutrient Yields from Streams Draining Boreal Forest and Fen Watersheds: Nitrogen and Phosphorus
Authors: Bayley S. E. , Schindler D. W. , Beaty K. G. , Parker B. R. , Stainton M. P.
Published: April 2008

Wildfire in the boreal forests at the Experimental Lakes Area in Ontario caused significant losses of nitrogen and phosphorus in streams. Both watershed type and fire intensity appear to determine the extent of losses. The Northeast wetland basin lost more N and P, especially TDN, TDP, TN, and TP, than did terrestrial basins, although nitrate losses were higher from terrestrial basins. Losses of nutrients after the second fire generally were not as high as after the first fire. In the East basin, which burned twice with a high fire intensity, stream concentrations of NO3−, TDN, and TN were elevated for 6 yr between the fires and remained elevated for 9 yr after the second fire In contrast, the Northwest basin burned with a lower intensity and had no significant increase in annual concentrations of P or most forms of N in the first 3 yr after the fire; only NCV concentrations increased during this period. Despite the increases in export after wildfire, net retention of TN and TP over the 18-yr period was high. In the Northeast, East, and Northwest basins, retention of TN averaged 77, 80, and 87% compared with TP retention of 51, 67, and 84%.
TheTsn1–ToxA interaction in the wheat–Stagonospora nodorum pathosystem parallels that of the wheat–tan spot system
Authors: Liu Zhaohui , Friesen Timothy L. , Ling Hua , Meinhardt Steven W. , Oliver Richard P. , Rasmussen Jack B. , Faris Justin D.
Published: April 2008

The wheat tan spot fungus ( Pyrenophora tritici-repentis ) produces a well-characterized host-selective toxin (HST) known as Ptr ToxA, which induces necrosis in genotypes that harbor the Tsn1 gene on chromosome 5B. In previous work, we showed that the Stagonospora nodorum isolate Sn2000 produces at least 2 HSTs (SnTox1 and SnToxA). Sensitivity to SnTox1 is governed by the Snn1 gene on chromosome 1B in wheat. SnToxA is encoded by a gene with a high degree of similarity to the Ptr ToxA gene. Here, we evaluate toxin sensitivity and resistance to S. nodorum blotch (SNB) caused by Sn2000 in a recombinant inbred population that does not segregate for Snn1. Sensitivity to the Sn2000 toxin preparation cosegregated with sensitivity to Ptr ToxA at the Tsn1 locus. Tsn1-disrupted mutants were insensitive to both Ptr ToxA and SnToxA, suggesting that the 2 toxins are functionally similar, because they recognize the same locus in the host to induce necrosis. The locus harboring the tsn1 allele underlies a major quantitative trait locus (QTL) for resistance to SNB caused by Sn2000, and explains 62% of the phenotypic variation, indicating that the toxin is an important virulence factor for this fungus. The Tsn1 locus and several minor QTLs together explained 77% of the phenotypic variation. Therefore, the Tsn1–ToxA interaction in the wheat–S. nodorum pathosystem parallels that of the wheat–tan spot system, and the wheat Tsn1 gene serves as a major determinant for susceptibility to both SNB and tan spot.
Identification of common root-lesion nematode (Pratylenchus thornei Sher et Allen) loci in bread wheat
Authors: Toktay Halil , McIntyre C. Lynne , Nicol Julie M. , Ozkan Hakan , Elekcioglu Halil I.
Published: April 2008

Plant parasitic nematodes are a major biotic cause of wheat-yield loss in temperate wheat-growing regions. A major strategy to develop resistance to root-lesion nematodes (RLNs) in wheat is to assess and then exploit their natural genetic variation. This study examines RLN (Pratylenchus thornei) resistance in 1 Middle Eastern landrace (AUS4930 7.2) and 1 synthetic hexaploid wheat, CROC_1/AE.SQUARROSA (224)//OPATA (CROC), using F2 and F9 populations generated by crossing AUS4930 7.2 and CROC with the susceptible cultivar Pastor, and inoculating these crosses with P. thornei in greenhouse trials. Wheat microsatellite markers linked to previously identified quantitative trait loci (QTLs) for resistance to P. thornei and P. neglectus were used to screen both populations. In the AUS4930 7.2 × Pastor population, resistance loci on chromosomes 1B, 2B, and 6D were detected. Similarly, in the CROC × Pastor population, 2 resistance loci, located on chromosomes 1B and 3B, were identified. Interestingly, a resistance locus located on chromosome 6D was not detected. More detailed mapping is required in these 2 populations, developed using new RLN resistance sources, to determine whether the QTLs identified on these chromosomes are the same, are allelic, or are linked to different resistance loci from those previously identified, and to determine whether these 2 sources contain other novel resistance loci.
Molecular mapping of the shrunken endosperm genesseg8andsex1in barley (Hordeum vulgareL.)
Authors: Röder Marion S. , Kaiser Christian , Weschke Winfriede
Published: April 2008

A number of mutations affecting seed development in barley (Hordeum vulgare L.) have been known for many years; however, to date, no research has been reported that elucidates the molecular structure of the causal genes. As a first step, we initiated the linkage mapping of the two shrunken endosperm genes seg8 and sex1 using microsatellite markers. The recessive gene seg8 was mapped in the centromeric region of chromosome 7H to a 4.6 cM interval flanked by markers GBM1516 and Bmag341. The recessive sex1 gene showed xenia effects and was located in the centromeric region of barley chromosome 6H, which is in accordance to the previously reported chromosomal location in the classical linkage map. It was flanked by markers GBM5012 and GBM1063 in a 4.2 cM interval. EST-derived microsatellite markers were used to establish the syntenic relationships to the genomic rice sequences. Two orthologous sites on rice chromosome 2 flanking a 4.1 Mb sequence had homology to the respective barley markers in the sex1 region. For the markers in the seg8 region orthologous sites on rice chromosome 6 were detected.
Structural and functional analyses of the wheat genomes based on expressed sequence tags (ESTs) related to abiotic stresses
Authors: Ramalingam J. , Pathan M.S. , Feril O. , Miftahudin  , Ross K. , Ma X.-F. , Mahmoud A.A. , Layton J. , Rodriguez-Milla M.A. , Chikmawati T. , Valliyodan B. , Skinner R. , Matthews D.E. , Gustafson J.P. , Nguyen H.T.
Published: April 2008

To gain insights into the structure and function of the wheat (Triticum aestivum L.) genomes, we identified 278 ESTs related to abiotic stress (cold, heat, drought, salinity, and aluminum) from 7671 ESTs previously mapped to wheat chromosomes. Of the 278 abiotic stress related ESTs, 259 (811 loci) were assigned to chromosome deletion bins and analyzed for their distribution pattern among the 7 homoeologous chromosome groups. Distribution of abiotic stress related EST loci were not uniform throughout the different regions of the chromosomes of the 3 wheat genomes. Both the short and long arms of group 4 chromosomes showed a higher number of loci in their distal regions compared with proximal regions. Of the 811 loci, the number of mapped loci on the A, B, and D genomes were 258, 281, and 272, respectively. The highest number of abiotic stress related loci were found in homoeologous chromosome group 2 (142 loci) and the lowest number were found in group 6 (94 loci). When considering the genome-specific ESTs, the B genome showed the highest number of unique ESTs (7 loci), while none were found in the D genome. Similarly, considering homoeologous group-specific ESTs, group 2 showed the highest number with 16 unique ESTs (58 loci), followed by group 4 with 9 unique ESTs (33 loci). Many of the classified proteins fell into the biological process categories associated with metabolism, cell growth, and cell maintenance. Most of the mapped ESTs fell into the category of enzyme activity (28%), followed by binding activity (27%). Enzymes related to abiotic stress such as β-galactosidase, peroxidase, glutathione reductase, and trehalose-6-phosphate synthase were identified. The comparison of stress-responsive ESTs with genomic sequences of rice (Oryza sativa L.) chromosomes revealed the complexities of colinearity. This bin map provides insight into the structural and functional details of wheat genomic regions in relation to abiotic stress.
High temperature fluidized bed zero valent iron process for flue gas nitrogen monoxide removal
Authors: Cheng Chih-Yu , Chen Shiao-Shing , Tang Chih-Hui , Chang Yu-Min , Cheng Hsu-Hui , Liu Hsuan-Liang
Published: April 2008

A fluidized bed zero valent iron (ZVI) reactor was designed for nitrogen monoxide (NO) removal with typical flue gas temperatures based on ZVI’s strong reducing abilities. Three different parameters: temperature, influent concentration, and ZVI dosage were tested. Higher NO removals were observed for higher temperature, which was contributed to either higher diffusivity for NO or higher rate constant at higher temperature instead of thermodynamic aspect, since enthalpy change of the chemical reaction (ΔH) is negative and equilibrium constant is decreased when temperature is increased. At the same temperature, ZVI capacities (as mg NO/g ZVI) were constant for both influent concentration and ZVI dosage variation. Activated energies were determined for two different stages: before and after breakthrough. Before breakthrough, excess ZVI was presented and the reaction was described as a pseudo-first order reaction, and the activated energy (Ea) for the first stage was calculated as 46.5 kJ/mol according to the Arrhenius equation. After breakthrough, the presence of ZVI was not in excess and the reaction order of ZVI and NO was considered as 2nd order (1 order in [NO] and 1 order in ZVI), and Ea was determined to be 7.5 kJ/mol.
Characterization of PM2.5 and conversion rate of sulfur dioxide to sulfate in inland areas of Taiwan
Authors: Horng Chuen-Liang , Cheng Man-Ting
Published: April 2008

The purpose of this study was to investigate the sulfur conversion rate and the characterization of PM2.5 particulate matter and acidic gases in inland Taiwan region. The measurements were taken at two different sites located near the fossil fuel power plant in central Taiwan. First site was Wufong and the other site was Nantou, which is located 15 km south from Wufong. PM2.5 and gaseous acids were measured by annular denuder system. PM2.5 ionic species including SO42–, NO3–, NH4+, Cl–, Ca2+, K+, Na+, and H+and gaseous HNO3 and HCl were analyzed. Results showed that the average ratio of PM2.5 and SO42– was higher during daytime, probably due to the anthropogenic activities. Wind field map also clearly displayed that Wufong was located upwind and Nantou was located downwind during daytime. Sulfur conversion ratio in the downwind site was higher than upwind site. Experimental data showed that sulfur conversion rate between these sites was 5%–9% h–1. The increased PM2.5 and SO2 concentrations recorded in the Nantou site were from the direction of Taichung city during daytime.
Petroleum contamination characterization and quantification using fluorescence emission-excitation matrices (EEMs) and parallel factor analysis (PARAFAC)
Authors: Alostaz Moh’d , Biggar Kevin , Donahue Robert , Hall Gregory
Published: April 2008

This paper introduces a novel approach to characterize and semi-quantify common petroleum contaminants (natural gas condensate, gasoline, diesel, flare pit residue, and heavy crude oil) and their underlying aromatic hydrocarbon components in solutions based on their fluorescence spectral signatures. The method uses fluorescence excitation-emission matrices (EEMs) combined with multivariate statistical procedures: parallel factor analysis (PARAFAC) and soft independent method of class analogy (SIMCA) to identify the petroleum products. Quantitatively, fluorescence intensities of EEMs of analyzed petroleum products at different concentrations are used to establish standard calibration curves that can be employed to estimate unknown concentrations of similar petroleum products in solutions. As well, underlying aromatic hydrocarbon component concentrations are estimated by performing customized PARAFAC analysis. This approach provides fingerprints for different petroleum products along with estimates of their concentrations in non-fluorescing solvents. Concentrations of predicted PARAFAC components were validated by laboratory chemical analytical results of the same petroleum products.
A field-based procedure for determining number of waste sorts for solid waste characterization
Authors: Sharma Mukesh , McBean Edward
Published: April 2008

Current methodologies for estimating the number of waste sorts require prior information on statistics (mean and standard deviation) for specific waste categories. The methods often require an iterative procedure or computer software to estimate the number of sorts required and the required statistics may change both spatially and temporally. To overcome the need for prior statistical information and avoid the need for iterative effort, a real-time methodology is developed to determine the required number of waste sorts for a waste category while sampling in the field for solid waste characterization. The information on required numbers of waste sorts is field-based and evolves during the sampling by utilizing real-time data to characterize the means and standard deviations. The proposed approach does not require prior information. The application of proposed methodology is demonstrated using the data from the Greater Vancouver Regional District (GVRD) for the primary categories of paper, glass, and secondary category glass-beverage.
Comparison between complete and partial recovery of N and P from stale human urine with MAP crystallization
Authors: Liu Z.G. , Zhao Q.L. , Wang K. , Qiu W. , Li W. , Wang J.F.
Published: April 2008

To provide an option of magnesium ammonium phosphate (MAP) crystallization for different recovery objective and treatment aim of separated stale human urine, five lab-scale tests were conducted, among which two of them acted as complete N and P recovery and three of them as partial N and complete P recovery, respectively. The results showed the recovery efficiencies of PO43–-P were more than 85% when the molar ratio of Mg/N/P was above the needed stoichiometric proportion for MAP precipitation. Although higher recovery efficiencies of NH4+-N and PO43–-P could be obtained by adding more phosphate and magnesium salts during MAP precipitation, there existed disadvantages such as inconvenient operation, hard to be put into practice, high operation cost, etc. Thus it was not recommended to completely recover NH4+-N and PO43–-P simultaneously if there were no wastes containing high phosphorus on hand. All harvested precipitates were identified as nearly pure struvite with the presence of trace elements of K, Na, Ni, Mn, and Ca.
Effect of initial microbial density on inactivation of Escherichia coli by monochloramine
Authors: Kaymak Baris , Haas Charles N.
Published: April 2008

Numerous water disinfection studies have reported deviations from the Chick-Watson Law, which was used to develop the Ct tables provided by the USEPA’s SWTR. Some of the modifications of the Chick-Watson Law incorporate explicit dependence on initial microbial density. In this study, a series of inactivation experiments were conducted with Escherichia coli cultured under three different growth conditions to investigate cell density effects on inactivation. Cell density dependent inactivation was observed in E. coli cultures grown on nutrient agar slant overnight and grown in chemostat with hydraulic residence time of 110 h. The disinfection efficiency was significantly (P < 0.05) greater at higher initial microbial density. Inactivation of E. coli cultured in nutrient broth for only 3 h was independent of cell density. These results have a major significance for utilities in terms of optimization of the disinfection process and balancing the risks associated with exposure to pathogens and disinfection/disinfectant byproducts.
One-pot preparation of β-amido ketones/esters in a three-component condensation reaction using magnesium hydrogensulfate as an effective and reusable catalyst
Authors: Shaterian Hamid Reza , Hosseinian Asghar , Ghashang Majid
Published: April 2008

A one-pot, three-component condensation of an aryl aldehyde, an enolizable ketone or β-keto ester, acetyl chloride, and acetonitrile or benzonitrile in the presence of magnesium hydrogensulfate as an active, recoverable, and reusable green catalyst is described for the synthesis of β-amido ketones/esters at room temperature. The key features of this methodology are simplicity, mild reaction conditions, and high to excellent yields.Key words: multi-component reaction, magnesium hydrogensulfate, heterogeneous catalyst, β-amido ketone/ester, mild conditions.
Reaction on a solid surface — A simple, economical, and efficient Mannich reaction of azacrown ethers over graphite
Authors: Sharghi Hashem , Khalifeh Reza
Published: April 2008

Graphite brings about a rapid Mannich reaction with a range of activated and unactivated phenolic compounds such as p-cresol and p-nitrophenol. The reactions are carried out with azacrown ether and paraformaldehyde in solvent-free conditions at 100 °C for 20–30 min. The graphite powder can be reused up to three times after simple washing with acetone.Key words: azacrown ether, lariat ether, graphite, solvent-free, Mannich reaction.
Correlation of the rates of solvolysis of acetyl chloride and α-substituted derivatives
Authors: D’Souza Malcolm J , Ryu Zoon Ha , Park Byoung-Chun , Kevill Dennis N
Published: April 2008

Additional specific rates of solvolysis have been determined for acetyl chloride and diphenylacetyl chloride. These are combined with literature values to carry out correlation analyses, using the extended Grunwald–Winstein equation with incorporation of literature values for solvent nucleophilicity (NT) and solvent ionizing power (YCl). Parallel analysis are carried out using literature values for the specific rates of solvolysis of trimethylacetyl chloride, chloroacetyl chloride, phenylacetyl chloride, and α-methoxy-α-trifluoromethylphenylacetyl chloride (MTPAC). Chloroacetyl chloride and MTPAC react by an addition-elimination pathway, with the addition step rate-determining, over the full range of solvents. Acetyl chloride reacts over the full range of solvents by an ionization pathway, with considerable nucleophilic solvation. The other three substrates can solvolyze with the domination of either mechanism, depending on the properties of the solvent. Reports concerning the use of product selectivity values, kinetic solvent isotope effects, and computational studies as additional probes of the mechanism of solvolysis are discussed.Key words: Grunwald-Winstein equation, acyl chlorides, mechanism of solvolysis, solvent nucleophilicity.
Oxyhalogen–sulfur chemistry — Kinetics and mechanism of the bromate oxidation of cysteamine
Authors: Morakinyo Moshood K , Chikwana Edward , Simoyi Reuben H
Published: April 2008

The kinetics and mechanism of the oxidation of the biologically important molecule, cysteamine, by acidic bromate and molecular bromine have been studied. In excess acidic bromate conditions, cysteamine is oxidized to N-brominated derivatives, and in excess cysteamine the oxidation product is taurine according to the following stoichiometry: BrO3–+ H2NCH2CH2SH → H2NCH2CH2SO3H + Br–. There is quantitative formation of taurine before N-bromination commences. Excess aqueous bromine oxidizes cysteamine to give dibromotaurine: 5Br2+ H2NCH2CH2SH + 3H2O → Br2NCH2CH2SO3H + 8Br–+ 8H+, while excess cysteamine conditions gave monobromotaurine. The oxidation of cysteamine by aqueous bromine is effectively diffusion-controlled all the way to the formation of monobromotaurine. Further formation of dibromotaurine is dependent on acid concentrations, with highly acidic conditions inhibiting further reaction towards formation of dibromotaurine. The formation of the N-brominated derivatives of taurine is reversible, with taurine regenerated in the presence of a reducing agent such as iodide. This feature makes it possible for taurine to moderate hypobromous acid toxicity in the physiological environment.Key words: cysteamine, hypobromous acid, toxicities, antioxidant.
Frontier orbital interactions in the hetero Diels–Alder cycloaddition of diazadienes
Authors: Sharma Pratibha , Kumar Ashok , Sahu Vinita , Singh Jitendra
Published: April 2008

This work deals with the molecular orbital calculation studies performed on different diazadienes to assess their reactivity pattern. The interaction of these diazadienes with various electron-poor and electron-rich dienophiles leads to the formation of diazines and tetrazines as the cycloadducts. The results from frontier orbital interactions were used to rationalize the reactivity and predictability of NDAC and IEDDAC reaction pathways. Correlation studies were also performed to predict reactivity sequence using a number of electronic descriptors, such as electrophilicity index (ω), chemical potential (µ), electronic charge ΔNmax, and chemical hardness η. Moreover, these studies exhibit good compatibility with experimental observations.Key words: AM1, MNDO, PM3, diazadienes, tetrazines, electrophilicity index, chemical potential.
Determination of dissociation constants of p-hydroxybenzophenone in aqueous organic mixtures – Solvent effects
Authors: Sancho M I , Jubert A H , Blanco S E , Ferretti F H , Castro E A
Published: April 2008

The apparent acidity constant of p-hydroxybenzophenone, which is a practically insoluble drug in water but of great pharmaceutical interest, was determined by reversed-phase high-performance liquid chromatography in organic solvent – water mixtures (acetonitrile–water, ethanol–water, and methanol–water), varying the reaction medium permittivity in the interval 56 to 70, at constant ionic strength (0.050) and temperature (30 °C). A combined glass electrode calibrated with aqueous standard buffers was used to obtain pH readings based on the concentration scale (swpH). The pKa values from chromatographic data were obtained using the Hardcastle–Jano equation. Moreover, excellent linear relationships between the pKa values and solvation properties of the reaction medium (relative permittivity and Acity) were used to derive acid dissociation constants in aqueous solution. It has been concluded that the pKa values extrapolated from such solvent–water mixtures are consistent with each other and with previously reported measurements. In addition, the molecular structures of all the chemical species involved in the acid–base dissociation equilibrium studied were calculated with a B3LYP/6–311++G(d,p) method that makes use of the polarizable continuum model (PCM). Taking into account the theoretical pKa values, the conclusions obtained match our experimental determinations.Key words: solvent effects, p-hydroxybenzophenone, acidity constant, solvation parameters, structure, DFT calculation.
Compatible basal-area growth and yield model for thinned and unthinned stands
Authors: Bailey Robert L. , Ware Kenneth D.
Published: April 2008

A measure of kind and level of thinning is developed and its relationship to other stand attributes such as number of trees, basal area, and volume removed in thinning is quantified. This measure or thinning index is based on the ratio of the quadratic mean diameter of thinned trees to the quadratic mean diameter of all trees before thinning. The thinning index is then logically incorporated into a thinning multiplier from which is derived a compatible basal-area growth projection model to generalize the previous concepts for thinning effects in systems for predicting growth and yield. Empirical tests with data from thinned and unthinned natural stands of loblolly pine, from thinned and unthinned slash pine plantations, and from thinned western larch stands show the model to provide estimates with improved properties. Hence, the thinning index and the thinning multiplier are also proposed for other situations involving effects of thinning.
Apical control of branch movements and tension wood in black cherry and white ash trees
Authors: Wilson Brayton F. , Archer Robert R.
Published: April 2008

We measured x,y coordinates and growth of 2-year-old branches on ash (Fraxinusamericana L.) and cherry (Prunusserotina Ehrh.) trees through one season of growth. We sectioned the branches at the end of the season and calculated stresses developed by new wood cells through the season. There were three treatments: (1) control, (2) stem girdled above the branch, and (3) stem girdled as in (2), with indolebutyric acid in lanolin added to the girdle (IBA). All branches first moved down, then stopped in controls, reversed to relatively rapid upward movement in treatment 2 and moved slowly upward in IBA treatments. In treatment 2, compared with controls, branches grew more in diameter, particularly on the upper side and at the branch base; stem growth below the branch was reduced; tension wood (TW) formed in ash branches and TW with greater tensile stress than in controls formed in cherry branches. Branches in IBA treatments had diameter growth and TW formation intermediate between control and treatment 2 branches.
Responses of Pinusbanksiana and Pinusresinosa seedlings to flooding
Authors: Tang Z. C. , Kozlowski T. T.
Published: April 2008

Flooding of soil for 45 days severely inhibited growth of 115-day-old Pinusbanksiana Lamb, and P. resinosa Ait. seedlings, with significant effects apparent within 15 days after initiation of flooding. Both species adapted poorly to flooding of soil but P. banksiana was more adversely affected than P. resinosa as shown by earlier and more drastic reduction of growth in the former species. In both species flooding decreased the rate of height growth, production of secondary needles, dry weight increment, and relative growth rates of various plant parts. Root growth of both species was reduced more than shoot growth. The reduction in dry weight increment of root systems of both species reflected arrested branching and elongation of roots as well as decay of roots, mainly the very small nonwoody roots. Flooding slightly stimulated ethylene production by submerged stems.
Effect of root zone temperature on ectomycorrhiza and vesicular–arbuscular mycorrhiza formation in disturbed and undisturbed forest soils of southwest Oregon
Authors: Parke Jennifer L. , Linderman R. G. , Trappe J. M.
Published: April 2008

The presence of ectomycorrhizal and vesicular–arbuscular (VA) mycorrhizal fungi in soils from five sites in a mixed conifer zone in southwest Oregon, each consisting of a 1- to 1.5-year-old clear-cut adjacent to an undisturbed forest stand, was determined by bioassay with Pseudotsugamenziesii (Mirb.) Franco, Pinusponderosa Dougl. ex P. Laws & C. Laws, and Trifoliumsubterraneum L. 'Mt. Barker' as hosts grown at root zone temperatures ranging from 7.5 to 35 °C. Maximum formation of both ectomycorrhizae and VA mycorrhizae occurred at 18.5–24 °C in soils from all sites, and there were no significant qualitative or quantitative differences between disturbed (clear-cut) or undisturbed (forest) soils. Mycorrhiza formation was moderate even at the lowest temperature tested (7.5 °C) but was greatly reduced or prevented at or above 29.5 °C. Treatment of soil at 35 °C for 1 week did not appear to adversely affect viability of ectomycorrhizal fungus propagules, but young mycorrhizae subjected to the same treatment appeared to be severely injured. Thus the ability of native mycorrhizal fungi to grow at low soil temperatures is especially important as they may contribute to the survival of seedlings outplanted into climatic zones characterized by warm, dry summers following cool, wet winters and springs.
Site-specific growth and nutrition of planted Piceamariana in the Ontario Clay Belt.: I. Early performance
Authors: Munson A. D. , Timmer V. R.
Published: April 2008

Piceamariana (Mill.) B.S.P. (black spruce) seedlings were outplanted in three black spruce dominated ecosystems (operational groups of the regional Forest Ecosystem Classification system) of the Clay Belt and also planted in pots of intact forest humus substrates from these sites to investigate response to site nutrient condition, to diagnose limiting nutrients, and to test the effectiveness of a bioassay relative to field results. Over two seasons, growth was consistently superior on upland Feathermoss substrates, intermediate on Alnus–Herb poor substrates, and poorest on Ledum substrates, in both field and pot experiments. The inferior performance of seedlings on lowland sites was related by plant analysis to low N uptake on sphagnum-dominated substrates. Vector analysis of shoot nutrient concentration, content, and dry mass allowed simultaneous comparison of the nutrient status of seedlings outplanted on the three sites. Lower total N and higher C:N ratio in forest humus substrates on the Alnus and Ledum sites suggested that N availability may be low. The pot experiment demonstrated close correspondence with field results in the first season, indicating that a bioassay may be most useful for assessing short-term response and diagnosing nutritional factors affecting early performance.
Provenance variation for disease resistance in Pseudotsugamenziesii to the Swiss needle-cast pathogen, Phaeocryptopusgaeumannii
Authors: McDermott J. M. , Robinson R. A.
Published: April 2008

Nine provenances of Douglas-fir, Pseudotsugamenziesii, were examined for the presence of Swiss needle-cast pathogen, Phaeocryptopusgaeumannii, in a plantation at the University of British Columbia Research Forest, Haney, B.C. The provenances were represented in a randomized complete block design. A severe epidemic of Swiss needle cast had persisted in the plantation for a number of years. Fructification of the fungus on more than 75% of the foliage provided an opportunity to assess provenance variation in disease resistance. Analysis of variance demonstrated that there are significant differences among provenances in resistance, as indicated by needle retention, to the Swiss needle-cast pathogen. Linear regression indicated a positive relationship between needle loss and the proportion of the remaining needles with pseudothecia. Provenance variation for needle retention and fructifying needles both correlate strongly with rainfall data from the meteorological station nearest to each provenance origin. This result is consistent with the hypothesis that the provenances of Douglas-fir may have evolved in response to selection pressure imposed by the biological stress of Swiss needle-cast disease.
Mechanistically based, allometric models to predict tree diameter and height in even-aged monoculture of Eucalyptusregnans F. Muell.
Authors: West P. W. , Beadle C. L. , Turnbull C. R. A.
Published: April 2008

A randomly selected sample of 22 trees was felled in a stand in a 20-year-old monoculture of Eucalyptusregnans F. Muell. in southern Tasmania. One-half of the trees were from a section of the stand that had been heavily thinned 10 years previously, and the remainder were from the unthinned section. The trees were sectioned and the fresh weights of their stems (including bark) and crowns (leaves plus branches) determined. By combining a geometrical argument about the shape of tree stems with a structural argument about their vertical stability, allometric relationships were established relating tree diameter at breast height or tree height to total aboveground weight and the ratio of crown to stem weight. These relationships were found to hold in both the thinned and unthinned sections of the experiment. When combined with a model to predict biomass of individual trees, these models can be used to predict diameter or height of individual trees in E. regnans monoculture.
Regeneration of Robiniapseudoacacia via somatic embryogenesis
Authors: Merkle S. A. , Wiecko A. T.
Published: April 2008

Tissue cultures were initiated from developing seeds of black locust (Robiniapseudoacacia L.) collected from three trees at weekly intervals from 1 week following anthesis until early fruit maturity. Explants were cultured on media containing 0, 2, or 4 mg/L 2,4-dichlorophenoxyacetic acid and 0 or 0.25 mg/L 6-benzyladenine. Seeds explanted onto hormone-supplemented media remained on these media for 1 or 3 weeks before being placed on hormone-free media, or were maintained on hormone-supplemented media for the entire study. Direct somatic embryogenesis was observed in a single culture, initiated from a seed collected 4 weeks after anthesis and cultured for 1 week on a medium supplemented with 4 mg/L 2,4-dichlorophenoxyacetic acid and 0.25 mg/L 6-benzyladenine before transfer to basal medium. Although it could not be discerned from which part of the explant somatic embryos were derived, secondary embryogenesis continued from the radicles of cotyledonary-stage somatic embryos. Most somatic embryos were well formed, with two distinct cotyledons. Embryos germinated precociously, producing plantlets that were initially weak but later gained vigor and resembled seedlings.
THE PHYSICS OF BURNING PLASMAS IN TOROIDAL MAGNETIC FIELD DEVICES
Authors: ZONCA FULVIO
Published: April 2008

Some of the crucial physics aspects of burning plasmas magnetically confined in toroidal systems are presented from the viewpoint of nonlinear dynamics. Most of the discussions specifically refer to tokamaks, but they can be readily extended to other toroidal confinement devices. Particular emphasis is devoted to fluctuation induced transport processes of mega electron volts energetic ions and charged fusion products as well as to energy and particle transports of the thermal plasma. Long time scale behaviors due to the interplay of fast ion induced collective effects and plasma turbulence are addressed in the framework of burning plasmas as complex self-organized systems. The crucial roles of mutual positive feedbacks between theory, numerical simulation and experiment are shown to be the necessary premise for reliable extrapolations from present day laboratory to burning plasmas. Examples of the broader applications of fundamental problems to other fields of plasma physics and beyond are also given.
FUNDAMENTAL SYMMETRIES OF THE EXTENDED SPACETIME
Authors: LECIAN ORCHIDEA MARIA , MONTANI GIOVANNI
Published: April 2008

On the basis of Fourier duality and Stone-von Neumann theorem, we will examine polymer-quantization techniques and modified uncertainty relations as possible 1-extraD compactification schemes for a phenomenological truncation of the extraD tower.
ON MATTER COUPLING IN 5D KALUZA-KLEIN MODEL
Authors: LACQUANITI VALENTINO , MONTANI GIOVANNI
Published: April 2008

We analyze some unphysical features of the geodesic approach to matter coupling in a compactified Kaluza-Klein scenario, like the q/m puzzle and the huge massive modes. We propose a new approach, based on Papapetrou multipole expansion, that provides a new equation for the motion of a test particle. We show how this equation provides right couplings and does not generate huge massive modes.
SINGLE CRYSTALLINE a-AXIS ZnO THIN FILMS DEPOSITED BY SOL-GEL METHOD FOR OPTOELECTRONIC DEVICES
Authors: BHOLE M. P. , PATIL D. S.
Published: April 2008

Undoped a-axis oriented single crystalline zinc oxide ( ZnO ) films were deposited by sol-gel dip-coating method. The films were characterized by X-ray diffraction (XRD) and ultraviolet visible (UV-VIS) absorbance spectra. The films of ZnO were deposited on amorphous microscopic glass substrate at various temperatures. The XRD showed that the ZnO film was crystallized with a hexagonal structure with a strong orientation in the (100) plane, which is exactly along the a-axis and beneficial for the development of optoelectronic devices. The optical band gap energy found for this a-axis oriented ZnO film was 3.30 eV through UV-VIS absorbance spectra. The Fourier Transform Infrared Spectroscopy (FTIR) analysis was carried out by taking the IR absorbance spectra for ZnO film deposited on the silicon substrate at 450°C. It showed that the strong Zn – O stretching bond is present in the deposited film.
VARIABLE GROUP VELOCITY SLOWDOWN IN SLOW-LIGHT MEDIA
Authors: QIU WEI , ZHANG YUNDONG , YE JIANBO , TIAN HE , WANG JIANFANG , WANG NAN , WANG HAO , YUAN PING
Published: April 2008

We investigated the variations of group velocity slowdown in erbium-doped optical fiber. According to the population oscillation effect, the numerical model of the group velocity slowdown was established. From the theoretical calculation, the group velocity slowdown is tunable due to the variety of steady ground state erbium ion population [Formula: see text]. To validate the effect of ion population for slow light, the experimental research was implemented via highly-doped erbium fiber.
STRUCTURE AND PROPERTIES OF CONCENTRATED FIBER SUSPENSIONS IN A SHEAR FLOW
Authors: LIN J. Z. , CHAI X. C. , FAN X. J.
Published: April 2008

The concentrated fiber suspensions in a simple shear flow are simulated numerically by taking into account the hydrodynamic interactions and fiber–fiber mechanical contacts. The orientation probability distribution of fibers, the specific viscosity and the first normal stress difference are obtained. The comparison of the specific viscosity to experimental data is made and the agreement is good. The results show that initially randomly-oriented fibers are re-oriented in the flow direction. The hydrodynamic interactions and fiber–fiber mechanical contacts result in an increase in the spread of the orientation distribution and asymmetric orientation distribution about the flow direction. Fiber's alignment with the flow direction becomes more obvious with an increasing shear rate. In a concentrated fiber suspension, the force induced by the fiber–fiber mechanical contact plays a more important role than that induced by hydrodynamic interactions. The specific viscosity of fiber suspension grows with concentration for various aspect ratios. For a fixed concentration, the larger the aspect ratio is, the higher the specific viscosity is. The specific viscosity calculated by taking into account both hydrodynamic interactions and fiber–fiber mechanical contacts is larger than that only taking into account the fiber–fiber mechanical contacts. The effect of aspect ratio on the first normal stress difference is more obvious at high concentration. Taking into account the hydrodynamic interactions or not will make a big difference in the first normal stress difference.
Conditional Cash Transfers as Social Policy in Latin America: An Assessment of their Contributions and Limitations
Authors: Valencia Lomelí Enrique
Published: April 2008

Conditional cash transfer programs have recently spread throughout Latin America, and early findings suggest their potential to overcome poverty and create human capital. This review undertakes an assessment of CCT programs and the conventional theory that has evolved to justify them. It concludes that successes to date are limited, with positive effects on schooling and some aspects of health and nutrition in poor households, but weak effects on alleviating poverty in the short term and uncertain effects on educational aspects of human capital formation and poverty reduction in the long term. In a broader and more comprehensive view of social policy, as opposed to a minimalist focus, the key issue is how to integrate CCT programs with other social programs to overcome traditional patterns of segmentation in Latin America and thereby cultivate citizenship.
Expression of energy balance regulatory genes in the developing ovine fetal hypothalamus at midgestation and the influence of hyperglycemia
Authors: Adam Clare L. , Findlay Patricia A. , Chanet Audrey , Aitken Raymond P. , Milne John S. , Wallace Jacqueline M.
Published: April 2008

Evidence suggests that the prenatal nutritional environment influences the risk of developing obesity, a major health problem worldwide. It is hypothesized that fetal nutrition influences the developing neuroendocrine hypothalamus, the integrative control center for postnatal energy balance regulation. The present aim was to determine whether relevant hypothalamic genes are expressed in midgestation and whether they are nutritionally (glucose) sensitive at this time. Hypothalami from a cohort of 81-day singleton sheep fetuses, with varying glycemia by virtue of maternal dietary and/or growth hormone treatment, were subject to in situ hybridization analysis for primary orexigenic, anorexigenic, and related receptor genes (term = 147 days, n = 24). Neuropeptide Y, agouti-related peptide, proopiomelanocortin (POMC), cocaine- and amphetamine-regulated transcript (CART), and insulin receptor mRNAs were all localized in the hypothalamic arcuate nucleus (ARC) of all fetuses, whereas leptin receptor mRNA was expressed more abundantly in the ventromedial hypothalamic nucleus. ARC expression levels of POMC and CART genes, but none of the other genes, were positively correlated with fetal plasma glucose concentrations. Therefore, key central components of adult energy balance regulation were already present as early as midgestation (equivalent to 22 wk in humans), and two anorexigenic components were upregulated by elevated glycemia. Such changes provide a potential mechanism for the prenatal origins of postnatal energy balance dysregulation and obesity.
Quantitative analysis of functional reconstructions reveals lateral and axial zonation in the renal inner medulla
Authors: Pannabecker Thomas L. , Henderson Cory S. , Dantzler William H.
Published: April 2008

Three-dimensional functional reconstructions of descending thin limbs (DTLs) and ascending thin limbs (ATLs) of loops of Henle, descending vasa recta (DVR), ascending vasa recta (AVR), and collecting ducts (CDs) permit quantitative definition of lateral and axial zones of probable functional significance in rat inner medulla (IM). CD clusters form the organizing motif for loops of Henle and vasa recta in the initial 3.0–3.5 mm of the IM. Using Euclidean distance mapping, we defined the lateral boundary of each cluster by pixels lying maximally distant from any CD. DTLs and DVR lie almost precisely on this independently defined boundary, placing them in the intercluster interstitium maximally distant from any CD. ATLs and AVR lie in a nearly uniform pattern throughout intercluster and intracluster regions, which we further differentiated by a polygon around CDs in each cluster. Loops associated with individual CD clusters show a similar axial exponential decrease as all loops together in the IM. Because ∼3.0–3.5 mm below the IM base CD clusters cease to form the organizing motif, all DTLs lack aquaporin 1 (AQP1), and all vasa recta are fenestrated, we have designated the first 3.0–3.5 mm of the IM the “outer zone” (OZ) and the final 1.5–2.0 mm the “inner zone” (IZ). We further subdivided these into OZ-1, OZ-2, IZ-1, and IZ-2 on the basis of the presence of completely AQP1-null DTLs only in the first 1 mm and on broad transverse loop bends only in the final 0.5 mm. These transverse segments expand surface area for probable NaCl efflux around loop bends from ∼40% to ∼140% of CD surface area in the final 100 μm of the papilla.