bluuebunny/crossref_metadata_2025 huggingface dataset:
Water Renewal Efficiency of Watershed and Lake Combinations in the ELA Region of the Precambrian Shield
Authors: Newbury R. W. , Beaty K. G.
Published: October 2008

Individual components of lakewater budgets in the Experimental Lakes Area (ELA) are highly variable through time. Direct field measurements combined with empirical relationships for unmeasurable components are required to achieve balanced lakewater budgets over short intervals of several hours or days. However, annual variations in the hydrological regime are related to a few simple characteristics of the lake and surrounding watershed. In the 1969–77 period the annual ratios of terrestrial evapotranspiration/precipitation and lake evaporation/precipitation showed little variation and were of a similar magnitude. As a result, the potential for water renewal or replacement in the lake basins annually can be characterized by only four factors: the annual precipitation, the tributary drainage basin area, the lake area, and the lake volume. The potential has been expressed as the Annual Watershed Efficiency (AWE), the reciprocal of the water renewal time, to obtain a linear relationship between the four variables. The AWE i a measure of the extent to which a particular watershed and lake combination can renew the lake water under various annual precipitation conditions. A general graphical relationship for the AWE has been prepared for small headwater lakes similar to those of the ELA for a range of annual precipitations.Key words: watershed hydrology, water renewal, water residence, precipitation/runoff ratios, water budgets, evaporation, watershed efficiency
Fates of Metal Radiotracers Added to a Whole Lake: Sediment–Water Interactions
Authors: Hesslein R. H. , Broecker W. S. , Schindler D. W.
Published: October 2008

A whole-lake radiotracer experiment with the isotopes Se-75, Hg-203, Cs-134, Fe-59, Co-60 was carried out in Lake 224 of the Experimental Lakes Area, northwestern Ontario. The results of the analyses of isotopes in the water column show an exponential decrease in concentration with time. The rate of loss from the water column does not show dependence on the affinity of the isotope for suspended particulate material. This affinity ranged from 98% for Fe-59 to < 1% for Cs-134 over the first 65 d. The major sink for isotopes lost from the water column is the sediments. Ratios of isotopes in the sediments show that those isotopes associated with suspended particulates more easily reach deep sediments than those in dissolved form which are restricted by the thermocline to adsorption to epilimnion sediments.Key words: Experimental Lakes Area, metal and radioisotope budgets, environmental fate of radionuclides
Experimental Studies on the Effect of Arsenic on Microbial Degradation of Organic Matter and Algal Growth
Authors: Brunskill G. J. , Graham B. W. , Rudd J. W. M.
Published: October 2008

Experiments were performed in tubes in Lake 303 at the Experimental Lakes Area to determine the effects of arsenate and arsenite on microbial degradation of organic matter, and to determine rates of reduction and oxidation of inorganic arsenic. Under winter ice, 40 μmol∙L−1 arsenate or arsenite inhibited microbial degradation of organic matter by 50%. Rates of oxidation of arsenite were about 2 μmol∙L−1∙d−1 under aerobic conditions, and rates of reduction of arsenate were about 1 μmol∙L−1∙d−1 under anaerobic conditions. During the ice-free season, arsenate and arsenite had little apparent effect upon rates of degradation of organic matter in lake tubes enriched with nutrients. Rates of formation of particulate phosphorus, and rates of planktonic uptake of dissolved phosphorus were depressed in the presence of arsenic. The observed rate of oxidation of arsenite in summer was similar to the winter value. Arsenate reduction rates ([Formula: see text]30 μmol∙L−1∙d−1) were very rapid under short periods of anaerobiosis. In the presence of large nutrient (N, P) concentrations, As did not inhibit the development of high algal biomass.Based on these experiments, we predict that addition of domestic sewage to arsenate-polluted Kam Lake (near Yellowknife, N.W.T.) will result in a state of restrained eutrophication. Degradation of organic matter will not be inhibited by As in summer, and dissolved phosphorus concentrations will remain high, due to As inhibition of P uptake by the plankton. During the summer, growth of algal blooms may be moderated by As, and more dissolved phosphorus will flow out of the lake to downstream waterbodies.Key words: arsenic, bacteria, algae, organic matter decomposition, eutrophication
Comparison of the Nitrogen-15 Uptake and Acetylene Reduction Methods for Estimating the Rates of Nitrogen Fixation by Freshwater Blue-Green Algae
Authors: Graham B. M. , Hamilton R. D. , Campbell N. E. R.
Published: October 2008

The relationship of acetylene reduction to nitrogen-15 uptake was investigated using blue-green algal populations in three lakes in the Experimental Lakes Area, northwestern Ontario. Nitrogen fixation rates, as estimated with both techniques, were compared and acetylene to nitrogen ratios determined. Lake ratios ranged from 6.3 to 9.1 moles of acetylene reduced per mole of nitrogen fixed varying from sample to sample and also with the method of calculation. Explanations of the discrepancies between theoretical and empirical ratios are discussed; these include hypotheses of excretion of assimilated nitrogen-15 labeled material and interference from nitrogenase-mediated hydrogen production.Key words: acetylene reduction, nitrogen-15 uptake, nitrogen fixation, C2H2/N2 ratio determination
Whole-Lake Model for the Distribution of Sediment-Derived Chemical Species
Authors: Hesslein R. H.
Published: October 2008

The distribution of CH4, ΣCO2, and NH3-N below the thermocline of Lake 227 can be reproduced using a simple numerical model. The model uses a constant vertical eddy diffusion coefficient and assumes the sediments to be the sole source of the chemical species. Analogs dependent on oxygen concentration can effectively represent conditions at the interface of the modeled region and the shallower depths in the lake. The best tit value for the vertical eddy diffusion coefficient is 3.1 × 10−3 cm2∙s−1. This is in good agreement with other independent measurements of this phenomena. The best fit fluxes of CH4, dissolved inorganic carbon and NH3-N are respectively: 13 × 10−3 mol∙m−2∙d−1, 7.5 × 10−3 mol∙m−2∙d−1, and 1.65 × 10−3 mol∙m−2∙d−1. The flux of methane is similar to that found in other small productive northern lakes and the ratio of CH4:ΣCO2 production of 1.73 falls in the range of values established for fermentation of mixed organic materials and sediments. The flux of ΣCO2 is 50–75% of the bicarbonate flux (10–15 × 10−3 mol∙m−2∙d−1) found previously in Linsley Pond, Connecticut.Key words: sediment–water interactions, methane, CO2, and ammonia fluxes, diffusion from sediments, Experimental Lakes Area
Characterizing In-stream Flow Refugia
Authors: Lancaster Jill , Hildrew Alan G.
Published: October 2008

Flow in nine streams was examined in relation to refugia for invertebrates. Areas of bed maintaining low hydraulic stress throughout the discharge hydrograph could provide flow refugia for animals during spates. In one stream, near-bed shear stress and velocity were repeatedly measured in discrete patches. Three types were identified: "fast" patches maintained high hydraulic stress, "variable" patches showed the greatest change in stress, and "slow" patches maintained low stress and thus were potential refugia. Average stress increased with discharge, but potential refugia were prominent throughout and could be important for invertebrates. Abundances of refugia in eight comparison streams were characterized by changes in the frequency distribution of flow forces with discharge. Three stream types were identified that did not simply reflect channel size or morphology. Such stream-specific flow patterns could affect the structure of comunities through the differing provision of refugia. Longitudinal transport processes in these streams were investigated by solute dilution experiments and by the application of a model to measure an aggregated "dead zone". Transport (and dead zone volume) varied among streams and further reflected their refuge potential. Clearly, flow habitat features could intervene in population and community dynamics by providing refuge from spates.
Mercury in Sediments and Sediment Pore Water in the Laurentian Trough
Authors: Gobeil Charles , Cossa Daniel
Published: October 2008

The concentration of dissolved mercury in the pore water of Laurentian Trough sediments varies between the detection limit (2.5 pM) and 64 pM, up to an order of magnitude enriched relative to the overlying water. Dissolved mercury is low near the sediment surface, increases with depth to 5 cm, and then decreases with further depth. Redistribution of remobilized mercury within the sediment column is, however, insufficient to explain the observed depth variations in mercury concentration. In the Lower St. Lawrence Estuary, the vertical profiles of mercury in trough sediments tend to be consistent with the chronology of mercury discharges from chlor-alkali plants located in the St. Lawrence drainage basin. The total amount of anthropogenic mercury in sediments deposited below the 200-m isobath in the entire lower St. Lawrence Estuary since the beginning of industrialization is estimated as 170 ± 85 × 103 kg, about six times the amount of natural mercury that has accumulated during the same period. Near the seaward end of the Trough in the Gulf of St. Lawrence, sedimentary mercury concentrations are much lower than in the Estuary, with a significant portion of the anthropogenic mercury deposited in the sediments probably coming from the atmosphere.
Construction and characterization of a sugar beet (Beta vulgaris) fosmid library
Authors: Lange Cornelia , Holtgräwe Daniela , Schulz Britta , Weisshaar Bernd , Himmelbauer Heinz
Published: October 2008

A sugar beet ( Beta vulgaris ) fosmid library from the doubled haploid accession KWS2320 encompassing 115 200 independent clones was constructed and characterized. The average insert size of the fosmid library was determined by pulsed field gel electrophoresis to be 39 kbp on average, thus representing 5.9-fold coverage of the sugar beet genome (758 Mbp). PCR screening of plate pools with primer pairs against nine sugar beet genes supported the insert size estimation. BLAST searches with 2951 fosmid end-sequences originating from 1510 clones (1536 clones attempted) revealed little contamination with organellar DNA (2.1% chloroplast DNA, 0.3% mitochondrial DNA). The sugar beet fosmid library will be integrated in the presently ongoing efforts to determine the sequence of the sugar beet genome. Fosmids will be publicly available in the format of plate pools and individual clones.
Comparison of genome structure between white clover and Medicago truncatula supports homoeologous group nomenclature based on conserved synteny
Authors: George Julie , Sawbridge Timothy I. , Cogan Noel O.I. , Gendall Anthony R. , Smith Kevin F. , Spangenberg German C. , Forster John W.
Published: October 2008

Computational analysis has been used to align the genetic map of white clover ( Trifolium repens L.) with the draft genome sequence of the model legume species Medicago truncatula Gaertn. In silico comparison based on white clover expressed sequence tags that contain simple sequence repeat loci revealed substantial macrosynteny between the genomes of these two species, which are closely related within the Trifolieae tribe of the Fabaceae family. Six of the eight homoeologous chromosome groups (HGs) of allotetraploid white clover show predominant relationships with single M. truncatula (Mt) chromosomes, while the two remaining groups may have participated in an evolutionary reciprocal translocation event. On this basis, a new chromosome nomenclature system for allotetraploid white clover is proposed such that HG A = 3, HG B = 8, HG C = 7, HG D = 4, HG E = 1, HG F = 2, HG G = 5, and HG H = 6. A rationalized linkage map ordering system has also been demonstrated. Improved knowledge of the relationships between agricultural and model forage legume genomes will facilitate prediction of gene location for key agronomic traits for pasture production.
Refinement of the locus for distal hereditary motor neuronopathy VII (dHMN-VII) and exclusion of candidate genes
Authors: Dick Katherine J. , McEntagart Meriel , Alwan Wisam , Reilly Mary , Crosby Andrew H.
Published: October 2008

Distal hereditary motor neuronopathy type seven (dHMN-VII) is an autosomal dominant condition characterized by distal muscular atrophy associated with unilateral or bilateral vocal cord paralysis. We previously mapped the dHMN-VII locus to chromosome 2q14 using a genome-wide linkage scan in a single large pedigree. Here we have performed more detailed microsatellite saturation analysis and also evaluated two new affected individuals not described in the original study. We have significantly refined the extent of the disease locus and show that two distinct regions of chromosome 2q14.2, comprising 9.2 Mb and 4.3 Mb separated by an unusual double recombination event, cosegregate with the disease phenotype. The proximal linked region is now defined by markers D2S3038–D2S160, and the distal region by D2S2970–D2S2969. Sequencing of 15 candidate genes within the critical interval has not yet revealed any pathogenic mutations. Inspection of genomic databases indicates that this refinement of the critical interval by 8.4 Mb reduces the number of candidate genes from ~400 to ~100.
Allelic analysis of stripe rust resistance genes on wheat chromosome 2BS
Authors: Luo P. G. , Hu X. Y. , Ren Z. L. , Zhang H. Y. , Shu K. , Yang Z. J.
Published: October 2008

Stripe rust, caused by Puccinia striiormis Westend f. sp. tritici, is one of the most important foliar diseases of wheat ( Triticum aestivum L.) worldwide. Stripe rust resistance genes Yr27, Yr31, YrSp, YrV23, and YrCN19 on chromosome 2BS confer resistance to some or all Chinese P. striiormis f. sp. tritici races CYR31, CYR32, SY11-4, and SY11-14 in the greenhouse. To screen microsatellite (SSR) markers linked with YrCN19, F1, F2, and F3populations derived from cross Ch377/CN19 were screened with race CYR32 and 35 SSR primer pairs. Linkage analysis indicated that the single dominant gene YrCN19 in cultivar CN19 was linked with SSR markers Xgwm410, Xgwm374, Xwmc477, and Xgwm382 on chromosome 2BS with genetic distances of 0.3, 7.9, 12.3, and 21.2 cM, respectively. Crosses of CN19 with wheat lines carrying other genes on chromosome 2B showed that all were located at different loci. YrCN19 is thus different from the other reported Yr genes in chromosomal location and resistance response and was therefore named Yr41. Prospects and strategies of using Yr41 and other Yr genes in wheat improvement for stripe rust resistance are discussed.
Meiotic events inOenothera — a non-standard pattern of chromosome behaviour
Authors: Golczyk Hieronim , Musiał Krystyna , Rauwolf Uwe , Meurer Jörg , Herrmann Reinhold G. , Greiner Stephan
Published: October 2008

The genus Oenothera shows an intriguing extent of permanent translocation heterozygosity. Reciprocal translocations of chromosome arms in species or populations result in various kinds of chromosome multivalents in diakinesis. Early meiotic events conditioning such chromosome behaviour are poorly understood. We found a surprising uniformity of the leptotene–diplotene period, regardless of the chromosome configuration at diakinesis (ring of 14, 7 bivalents, mixture of bivalents and multivalents). It appears that the earliest chromosome interactions at Oenothera meiosis are untypical, since they involve pericentromeric regions. During early leptotene, proximal chromosome parts cluster and form a highly polarized Rabl configuration. Telomeres associated in pairs were seen at zygotene. The high degree of polarization of meiotic nuclei continues for an exceptionally long period, i.e., during zygotene–pachytene into the diplotene contraction stage. The Rabl-polarized meiotic architecture and clustering of pericentromeres suggest a high complexity of karyotypes, not only in structural heterozygotes but also in bivalent-forming homozygous species.
Aluminum and calcium in fine root tips of red spruce collected from the forest floor
Authors: Smith K.T. , Shortle W.C. , Ostrofsky W.D.
Published: October 2008

Root chemistry is being increasingly used as a marker of biologically relevant soil chemistry. To evaluate this marker, we determined the precision of measurement, the effect of organic soil horizon, and the effect of stand elevation on the chemistry of fine root tips of red spruce (Picearubens Sarg.). Fine root tips were collected from the F and H horizons of the forest floor of nine locations. Six of the locations were selected as pairs that differed in elevation. The concentrations of Al, Ca, Mg, and Fe in fine root tip collections were determined by direct current plasma emission spectroscopy. Element concentrations were not well correlated between collections made from the F and H layers associated with individual trees. The concentration of Ca was significantly higher and the concentrations of Al and Fe were significantly lower in fine root tips collected from the F than in tips collected from the H horizons. Fine root tips collected from the higher elevation member of paired locations yielded a higher Al:Ca ratio than did those collected from the lower elevation member. These results indicated the need to stratify fine root collections by soil horizon within the forest floor.
Variation in wood structure of eastern larch defoliated by the larch sawfly in subarctic Quebec, Canada
Authors: Filion Louise , Cournoyer Luc
Published: October 2008

We studied the wood structure of eastern larch (Larixlaricina (Du Roi) K. Koch) affected by a larch sawfly (Pristiphoraerichsonii (Htg.)) infestation that occurred in 1939 in the Lac à l'Eau-Claire and Rivière-aux-Mélèzes areas, subarctic Quebec. The objective was to document variation in wood characteristics in relation to defoliation at three study sites. Lumen diameter of tracheids and cell wall thickness were measured from thin sections representing the 1931–1955 period. Significant changes in the wood structure of larch was noticed only at the Atkinson Island site, where the radial growth pattern was typical of the insect activity. A light ring was formed the 1st year of the infestation (1939). During the 2nd year (1940), the size of tracheids (lumen) decreased abruptly along with radial growth, while the proportion of latewood increased. The variation in wood anatomy among the three study sites paralleled that in radial growth. Wood structure appears to be a good indicator of the end of an infestation.
Incidence of wetwood and decay in precommercially thinned western hemlock stands
Authors: Shaw David C. , Edmonds Robert L. , Littke Willis R. , Browning John E. , Russel Kenelm W.
Published: October 2008

The occurrence and pattern of stains in the base and lower stem of young-growth western hemlock (Tsugaheterophylla (Raf.) Sarg.) and its relationship to root disease were studied at 16 sites in coastal Washington. Stands ranged in age from 17 to 35 years and were precommercially thinned 5–17 years previously. The most common stain was discolored wood or wetwood, which is a type of heartwood in standing trees that has been internally infused with water. Wetwood occurred in more than 50% of the 1215 trees examined, and within some stands it occurred in 80% of the trees examined. The presence of wetwood did not indicate root disease or other decay. However, all wood decay infections were associated with wetwood. Wetwood can be economically important because it interferes with drying and causes shake and warping in lumber. Incipient decay stain was less common (<6% of the trees) and was caused predominantly by the basidiomycete fungi Heterobasidionannosum (Fr.) Bref., Armillaria spp., and Perenniporiasubacida (Pk.) Donk. Wetwood appearance varied from bright pinkish, purplish, or pinkish brown to light brown, depending on moisture and extractives content. Incipient decay stain of H. annosum was distinguished from wetwood by its mostly brown, dark brown, or brownish black color. Heterobasidionannosum also has incipient decay stain that may be light brown to pinkish and closely resembles wetwood. Experimental wounding of trees resulted in both wetwood and incipient decay formation. Wetwood and incipient decay stain can occur in the same bole section, so there is a potential for confusing them. Cultural isolation of fungi is the only sure way to distinguish wetwood from incipient decay.
Balsam fir mortality following the last spruce budworm outbreak in northwestern Quebec
Authors: Bergeron Yves , Leduc Alain , Joyal Claude , Morin Hubert
Published: October 2008

Balsam fir (Abiesbalsamea (L.) Mill.) mortality caused by the last spruce budworm (Choristoneurafumiferana (Clem.)) outbreak (1970–1987) was studied in 624 sites belonging to a complex natural forest mosaic originating from different fires in northwestern Quebec. Multiple regression analyses were used to assess the respective effects of stand structure, species composition, site characteristics, and the forest composition surrounding the stand on observed stand mortality. Mortality was observed to increase in relation to diameter of the trees, basal area of balsam fir, and the number of stands dominated by conifers in the forest mosaic. All of these factors showed significant independent effects, but 60% of the variance remained unexplained. Site characteristics, however, did not show a significant relationship to stand mortality. The results suggest that forest composition at both the stand and the forest mosaic levels may be responsible for differing degrees of defoliation that result in differences in stand mortality. Forest management strategies that favor the presence of mixed compositions both at the stand level and at the mosaic level may contribute to decreased stand vulnerability.
THE UNIVERSAL COVER OF 3-MANIFOLDS BUILT FROM INJECTIVE HANDLEBODIES IS ℝ3
Authors: COFFEY JAMES
Published: October 2008

This paper gives a proof that the universal cover of a closed 3-manifold built from three π1-injective handlebodies is homeomorphic to ℝ3. This construction is an extension to handlebodies of the conditions for gluing of three solid tori to produce non-Haken Seifert fibered manifolds with infinite fundamental group. This class of manifolds has been shown to contain non-Haken non-Seifert fibered manifolds.
DOES FINITE KNOT ENERGY LEAD TO DIFFERENTIABILITY?
Authors: BLATT SIMON , REITER PHILIPP
Published: October 2008

In this article, we raise the question if curves of finite (j, p)-knot energy introduced by O'Hara are at least pointwise differentiable. If we exclude the highly singular range (j - 2)p ≥ 1, the answer is no for jp ≤ 2 and yes for jp > 2. In the first case, which also contains the most prominent example of the Möbius energy(j = 2, p = 1) investigated by Freedman, He and Wang, we construct counterexamples. For jp > 2, we prove that finite-energy curves have in fact a Hölder continuous tangent with Hölder exponent ½(jp - 2)/(p + 2). Thus, we obtain a complete picture as to what extent the (j, p)-energy has self-avoidance and regularizing effects for (j, p) ∈ (0, ∞) × (0, ∞). We provide results for both closed and open curves.
MULTISTAGE COMMUNICATION WITH AND WITHOUT VERIFIABLE TYPES
Authors: KOESSLER FRÉDÉRIC , FORGES FRANÇOISE
Published: October 2008

We survey selected results on strategic information transmission. We distinguish between "cheap talk" and "persuasion". In the latter model, the informed player's message set depends on his type. As a benchmark, we first assume that the informed player sends a single message to the decision maker. We state characterization results for the sets of equilibrium payoffs, with and without verifiable types. We then show that multistage, bilateral communication enables the players to achieve new equilibrium outcomes, even if types are verifiable. We also propose complete characterizations of the equilibrium payoffs that are achievable with a bounded number of communication rounds.
THE PROPORTIONAL LOTTERY PROTOCOL IS STRONGLY β-PARTICIPATORY AND VNM-STRATEGY-PROOF
Authors: VANNUCCI STEFANO
Published: October 2008

A voting protocol is said to be strongly β-participatory if for any voter i and any strategy profile either the outcome is i′s preferred one or i has a sincere strategy which would ensure her a better outcome, and VNM-strategy-proof if at any preference profile the set of sincere strategies of each voter is a VNM-stable set. It is shown that the proportional lottery (PL) modular voting protocol is both strongly β-participatory and VNM-strategy-proof.
INTEGRATING WALKING AND VISION TO INCREASE HUMANOID AUTONOMY
Authors: STASSE OLIVIER , SAÏDI FRANÇOIS , YOKOI KAZUHITO , VERRELST BJÖRN , VANDERBORGHT BRAM , DAVISON ANDREW , MANSARD NICOLAS , ESTEVES CLAUDIA
Published: October 2008

Aiming at building versatile humanoid systems, we present in this paper the real-time implementation of behaviors which integrate walking and vision to achieve general functionalities. The paper describes how real-time — or high-bandwidth — cognitive processes can be obtained by combining vision with walking. The central point of our methodology is to use appropriate models to reduce the complexity of the search space. We will describe the models introduced in the different blocks of the system and their relationships: walking pattern, self-localization and map building, real-time reactive vision behaviors, and planning.
Immunity to Respiratory Viruses
Authors: Kohlmeier Jacob E. , Woodland David L.
Published: October 2008

The respiratory tract is characterized by an extensive surface area that is in direct contact with the environment, posing a significant problem for effective immune surveillance. Yet most respiratory pathogens are quickly recognized and controlled by a coordinated response involving the innate and adaptive arms of the immune system. The investigation of pulmonary immunity to respiratory viruses during a primary infection has demonstrated that multiple innate and adaptive immune mechanisms are necessary for efficient antiviral responses, and the inhibition of any single mechanism can have disastrous consequences for the host. Furthermore, the investigation of recall responses in the lung has shown that protection from a secondary challenge infection is a complex and elegant process that occurs in distinct stages. In this review, we discuss recent advances that describe the roles of individual components during primary and secondary responses to respiratory virus infections and how these discoveries have added to our understanding of antiviral immunity in the lung.
Fed-state clamp stimulates cellular mechanisms of muscle protein anabolism and modulates glucose disposal in normal men
Authors: Adegoke Olasunkanmi A. J. , Chevalier Stéphanie , Morais José A. , Gougeon Réjeanne , Kimball Scot R. , Jefferson Leonard S. , Wing Simon S. , Marliss Errol B.
Published: October 2008

Since maximum anabolism occurs postprandially, we developed a simulated fed state with clamped hyperinsulinemia, physiological hyperglycemia, and hyperaminoacidemia (Hyper-3) and explored muscle cellular mechanisms. Whole body [1-13C]leucine and [3-3H]glucose kinetics in healthy men were compared between hyperinsulinemic, euglycemic, isoaminoacidemic (Hyper-1, n = 10) and Hyper-3 ( n = 9) clamps. In Hyper-3 vs. Hyper-1, nonoxidative leucine Rd [rate of disappearance (synthesis)] was stimulated more (45 ± 4 vs. 24 ± 4 μmol/min, P < 0.01) and endogenous Ra [rate of appearance (breakdown)] was inhibited similarly; hence net balance increased more (86 ± 6 vs. 49 ± 2 μmol/min, P < 0.001). Glucose Rd was similar; thus Hyper-3 metabolic clearance rate (331 ± 23 vs. 557 ± 41 ml/min, P < 0.0005) and Rd/insulin (M, 0.65 ± 0.10 vs. 1.25 ± 0.10 mg·min−1·pmol−1·l, P < 0.001) were less, despite higher insulin (798 ± 74 vs. 450 ± 24 pmol/l, P < 0.005). In vastus lateralis muscle biopsies, phosphorylation of Akt ( P = 0.025), mammalian target of rapamycin (mTOR), ribosomal protein S6 kinase (p70S6K1; P = 0.008), S6 ( P = 0.049), and 4E-binding protein 1 (4E-BP1; P = 0.001) increased. With decreased eukaryotic initiation factor-4E (eIF4E)·4E-BP1 complex ( P = 0.01), these are consistent with increased mTOR complex 1 (mTORC1) signaling and translation initiation of protein synthesis. Although mRNA expression of ubiquitin, MAFbx 1, and MuRF-1 was unchanged, total ubiquitinated proteins decreased 20% ( P < 0.01), consistent with proteolysis suppression. The Hyper-3 clamp increases whole body protein synthesis, net anabolism, and muscle protein translation initiation pathways and decreases protein ubiquitination. The main contribution of hyperaminoacidemia is stimulation of synthesis rather than inhibition of proteolysis, and it attenuates the expected increment of glucose disposal.
Dose-dependent effects of cholecystokinin-8 on antropyloroduodenal motility, gastrointestinal hormones, appetite, and energy intake in healthy men
Authors: Brennan Ixchel M. , Little Tanya J. , Feltrin Kate L. , Smout Andre J. P. M. , Wishart Judith M. , Horowitz Michael , Feinle-Bisset Christine
Published: October 2008

CCK mediates the effects of nutrients on gastrointestinal motility and appetite. Intravenously administered CCK stimulates pyloric pressures, increases plasma PYY, and suppresses ghrelin, all of which may be important in the regulation of appetite and energy intake. The dose-related effects of exogenous CCK on gastrointestinal motility and gut hormone release, and the relationships between these effects and those on energy intake, are uncertain. We hypothesized that 1) intravenous CCK-8 would have dose-dependent effects on antropyloroduodenal (APD) pressures, plasma PYY and ghrelin concentrations, appetite, and energy intake and 2) the suppression of energy intake by CCK-8 would be related to the stimulation of pyloric motility. Ten healthy men (age 26 ± 2 yr) were studied on four separate occasions in double-blind, randomized fashion. APD pressures, plasma PYY and ghrelin, and appetite were measured during 120-min intravenous infusions of 1) saline (“control”) or 2) CCK-8 at 0.33 (“CCK0.33”), 3) 0.66 (“CCK0.66”), or 4) 2.0 (“CCK2.0”) ng·kg−1·min−1. After 90 min, energy intake at a buffet meal was quantified. CCK-8 dose-dependently stimulated phasic and tonic pyloric pressures and plasma PYY concentrations ( r > 0.70, P < 0.05) and reduced desire to eat and energy intake ( r > −0.60, P < 0.05) without inducing nausea. There were relationships between basal pyloric pressure and isolated pyloric pressure waves (IPPW) with plasma CCK ( r > 0.50, P < 0.01) and between energy intake with IPPW ( r = −0.70, P < 0.05). Therefore, our study demonstrates that exogenous CCK-8 has dose-related effects on APD motility, plasma PYY, desire to eat, and energy intake and suggests that the suppression of energy intake is related to the stimulation of IPPW.
Structural and functional changes in the kidneys of high-fat diet-induced obese mice
Authors: Deji Naoko , Kume Shinji , Araki Shin-ichi , Soumura Mariko , Sugimoto Toshiro , Isshiki Keiji , Chin-Kanasaki Masami , Sakaguchi Masayoshi , Koya Daisuke , Haneda Masakazu , Kashiwagi Atsunori , Uzu Takashi
Published: October 2008

Metabolic syndrome has been reported to be associated with chronic kidney disease, but the mechanisms remain unclear. Although feeding of a high-fat diet (HFD) to C57BL/6 mice is reported to induce systemic metabolic abnormalities and subsequent renal injuries, such as albuminuria, similar to human metabolic syndrome, alterations in HFD-induced renal injuries have not been fully elucidated in detail. We therefore investigated the structural and functional changes in the kidneys of C57BL/6 mice on a HFD. Six-week-old mice were fed a low-fat diet (LFD; 10% of total calories from fat) or a HFD (60% fat) for 12 wk. Mice fed a HFD showed significant increases in body weight, systolic blood pressure, plasma insulin, glucose, and triglycerides compared with those on a LFD. Accompanying these systemic changes, mice on a HFD showed albuminuria, an increase in glomerular tuft area, and mesangial expansion. These systemic and renal alterations in mice on a HFD were prevented by body weight control with the dietary restriction of feeding a HFD. Furthermore, mice on a HFD showed renal pathophysiological alterations including renal lipid accumulation, an increased accumulation of type IV collagen in glomeruli, an increase in macrophage infiltration in the renal medulla, an increase in urinary 8-hydroxy-2′-deoxyguanosine excretion, and impaired sodium handling. In conclusion, this study suggests that local metabolic alterations in the kidney play important roles in the development of renal injury associated with metabolic syndrome in addition to systemic metabolic changes and an increase in body weight.
Age-Dependent Decline in Supragranular Long-Term Synaptic Plasticity by Increased Inhibition During the Critical Period in the Rat Primary Visual Cortex
Authors: Jang Hyun-Jong , Cho Kwang-Hyun , Kim Hyun-Sok , Hahn Sang June , Kim Myung-Suk , Rhie Duck-Joo
Published: October 2008

Supragranular long-term potentiation (LTP) and depression (LTD) are continuously induced in the pathway from layer 4 during the critical period in the rodent primary visual cortex, which limits the use of supragranular long-term synaptic plasticity as a synaptic model for the mechanism of ocular dominance (OD) plasticity. The results of the present study demonstrate that the pulse duration of extracellular stimulation to evoke a field potential (FP) is critical to induction of LTP and LTD in this pathway. LTP and LTD were induced in the pathway from layer 4 to layer 2/3 in slices from 3-wk-old rats when FPs were evoked by 0.1- and 0.2-ms pulses. LTP and LTD were induced in slices from 5-wk-old rats when evoked by stimulation with a 0.2-ms pulse but not by stimulation with a 0.1-ms pulse. Both the inhibitory component of FP and the inhibitory/excitatory postsynaptic potential amplitude ratio evoked by stimulation with a 0.1-ms pulse were greater than the values elicited by a 0.2-ms pulse. Stimulation with a 0.1-ms pulse at various intensities that showed the similar inhibitory FP component with the 0.2-ms pulse induced both LTD and LTP in 5-wk-old rats. Thus extracellular stimulation with shorter-duration pulses at higher intensity resulted in greater inhibition than that observed with longer-duration pulses at low intensity. This increased inhibition might be involved in the age-dependent decline of synaptic plasticity during the critical period. These results provide an alternative synaptic model for the mechanism of OD plasticity.
Timing of Impulses From the Central Amygdala and Bed Nucleus of the Stria Terminalis to the Brain Stem
Authors: Nagy Frank Z. , Paré Denis
Published: October 2008

The amygdala and bed nucleus of the stria terminalis (BNST) are thought to subserve distinct functions, with the former mediating rapid fear responses to discrete sensory cues and the latter longer “anxiety-like” states in response to diffuse environmental contingencies. However, these structures are reciprocally connected and their projection sites overlap extensively. To shed light on the significance of BNST–amygdala connections, we compared the antidromic response latencies of BNST and central amygdala (CE) neurons to brain stem stimulation. Whereas the frequency distribution of latencies was unimodal in BNST neurons (∼10-ms mode), that of CE neurons was bimodal (∼10- and ∼30-ms modes). However, after stria terminalis (ST) lesions, only short-latency antidromic responses were observed, suggesting that CE axons with long conduction times course through the ST. Compared with the direct route, the ST greatly lengthens the path of CE axons to the brain stem, an apparently disadvantageous arrangement. Because BNST and CE share major excitatory basolateral amygdala (BL) inputs, lengthening the path of CE axons might allow synchronization of BNST and CE impulses to brain stem when activated by BL. To test this, we applied electrical BL stimuli and compared orthodromic response latencies in CE and BNST neurons. The latency difference between CE and BNST neurons to BL stimuli approximated that seen between the antidromic responses of BNST cells and CE neurons with long conduction times. These results point to a hitherto unsuspected level of temporal coordination between the inputs and outputs of CE and BNST neurons, supporting the idea of shared functions.
Expression of genes involved in GABAergic neurotransmission in anoxic crucian carp brain (Carassius carassius)
Authors: Ellefsen Stian , Stensløkken Kåre-Olav , Fagernes Cathrine E. , Kristensen Tom A. , Nilsson Göran E.
Published: October 2008

The crucian carp, Carassius carassius, survives days to months without oxygen, depending on temperature. In the anoxic crucian carp brain, increased GABAergic inhibition, mediated by increased extracellular levels of GABA, has been shown to suppress electric activity and ATP consumption. To investigate an involvement of gene expression in this response, we utilized real-time RT-PCR to test the effect of 1 and 7 days anoxia (8°C) on the expression of 22 genes, including nine GABAAreceptor subunits (α1–6, β2, δ, and γ2), three GABABreceptor subunits (GB1a-1b and GB2), three enzymes involved in GABA metabolism (GAD65 and GAD67, GABAT), four GABA transporters (GAT1, 2a-b and 3), two GABAAreceptor-associated proteins (GABARAP 1 and 2), and the K+/Cl−cotransporter KCC2. While the expression of GABAAreceptor subunits was dominated by α4-, α6-, and δ-subunits, all of which are located to extrasynaptic sites in mammalian brains and respond to elevations in extracellular levels of GABA by showing tonic activity patterns, the expression of GABA transporters was dominated by GAT2 (a and b) and GAT3, which also show extrasynaptic location in mammals. These expression patterns differ from those observed in mammals and may be a prerequisite for GABAergic inhibition of anoxic metabolic rate in crucian carp. Furthermore, while the expression of the majority of the genes was largely unaltered by anoxia, the expression of GAT2 and GAT3 decreased to 20%. This suggests impairment of GABA transport, which could be a mechanism behind the accumulation of extracellular GABA and the increased GABAergic inhibition.
Possibilities of Simultaneous In‐Cylinder Reduction of Soot and NOx Emissions for Diesel Engines with Direct Injection
Authors: Wagner U. , Eckert P. , Spicher U.
Published: October 2008

Up to now, diesel engines with direct fuel injection are the
propulsion systems with the highest efficiency for mobile
applications. Future targets in reducing CO2 ‐emissions with regard
to global warming effects can be met with the help of these
engines. A major disadvantage of diesel engines is the high soot
and nitrogen oxide emissions which cannot be reduced completely
with only engine measures today. The present paper describes two
different possibilities for the simultaneous in‐cylinder reduction
of soot and nitrogen oxide emissions. One possibility is the
optimization of the injection process with a new injection
strategy the other one is the use of water diesel emulsions with
the conventional injection system. The new injection strategy for
this experimental part of the study overcomes the problem of
increased soot emissions with pilot injection by separating the
injections spatially and therefore on the one hand reduces the
soot formation during the early stages of the combustion and on
the other hand increases the soot oxidation later during the
combustion. Another method to reduce the emissions is the
introduction of water into the combustion chamber. Emulsions of
water and fuel offer the potential to simultaneously reduce NOx
and soot emissions while maintaining a high‐thermal efficiency.
This article presents a theoretical investigation of the use of
fuel‐water emulsions in DI‐Diesel engines. The numerical
simulations are carried out with the 3D‐CFD code KIVA3V. The use
of different water diesel emulsions is investigated and assessed with the numerical model.
Simulation of MASPn Experiments in MISTRA Test Facility with COCOSYS Code
Authors: Povilaitis Mantas , Urbonavičius Egidijus
Published: October 2008

An issue of the stratified atmospheres in the containments of nuclear power plants is still unresolved; different experiments are performed in the test facilities like TOSQAN and MISTRA. MASPn experiments belong to the spray benchmark, initiated in the containment atmosphere mixing work package of the SARNET network. The benchmark consisted of MASP0, MASP1 and MASP2 experiments. Only the measured depressurisation rates during MASPn were available for the comparison with calculations. When the analysis was performed, the boundary conditions were not clearly defined therefore most of the attention was concentrated on MASP0 simulation in order to develop the nodalisation scheme and define the initial and boundary conditions. After achieving acceptable agreement with measured depressurisation rate, simulations of MASP1 and MASP2 experiments were performed to check the influence of sprays. The paper presents developed nodalisation scheme of MISTRA for the COCOSYS code and the results of analyses. In the performed analyses, several parameters were considered: initial conditions, loss coefficient of the junctions, initial gradients of temperature and steam volume fraction, and characteristic length of structures. Parametric analysis shows that in the simulation the heat losses through the external walls behind the lower condenser installed in the MISTRA facility determine the long-term depressurisation rate.
Classification System for Minimally Invasive Thyroid Surgery
Authors: Terris David J. , Seybt Melanie W.
Published: October 2008

Background: Minimally invasive thyroid surgery has been increasingly embraced in the United States and elsewhere. The surgical standards have yet to emerge, resulting in a sometimes confusing assortment of designations for the techniques. Design:Evidence-based analysis of prospectively collected data from a consecutive, single-surgeon experience with minimally invasive and conventional thyroid surgery. Methods and Materials: Demographic parameters were obtained on patients undergoing thyroid surgery at the Medical College of Georgia from February 2003 to June 2007. Particular attention was paid to patient and tumor characteristics thought to have relevance to eligibility for minimally invasive thyroid surgery. Normally distributed variables were subjected to parametric tests, nonnormally distributed variables to nonparametric tests. Results: A total of 359 patients underwent thyroidectomy during the study period; there were 57 males and 302 females, with a mean (± standard deviation) age of 45.9 ± 15.1 years. Predictably, there was a strongly positive correlation between incision length and both the size of the nodule (p = 0.0001) and the patient body mass index (p = 0.0001). A classification system was designed which established distinct and discrete levels for minimally invasive thyroidectomy (MIT I, II and III). Conclusions: A patient- and disease-driven classification system for assigning eligibility for incremental levels of minimally invasive thyroid surgery is proposed. This system allows for both uniform reporting of outcome measures across patient populations and a logical basis for determining patient eligibility.
Estatura baja y estatura alta
Authors: Bramswig Jurgen H.
Published: October 2008

Fundamentalmente la estatura baja o la estatura alta es una variación normal en la talla. Forma parte del continuo de la curva de distribución gausiana normal, que define los límites inferior y superior de la normalidad como los percentiles 3 y 97. Dentro de este contexto, es muy importante diferenciar las variaciones normales en la talla y el crecimiento por medio de los estados patológicos. Las variaciones normales en la talla constituyen la estatura baja o alta familiar e idiopática. Las variaciones normales en el crecimiento se diagnostican como aceleración constitucional o retraso constitucional del crecimiento y la pubertad y se observan en todos los percentiles. Los pacientes con estados patológicos de la talla presentan habitualmente trastornos sindrómicos, esqueléticos o cromosómicos, como el síndrome de Russell-Silver o Marfan, la acondroplasia y el síndrome de Ullrich-Turner o Klinefelter. Muchos de los trastornos con la estatura baja se basan en un retraso intrauterino del crecimiento. La talla final (media) no necesariamente sigue el margen de tallas de referencia, sino que alcanza una talla por debajo o por encima del percentil 3 ó 97 de la población. Los pacientes con estados patológicos del crecimiento pueden presentar estatura baja, normal o alta. Tienen una velocidad de crecimiento reducida o incrementada, causada por una amplia variedad de enfermedades orgánicas o psicosomáticas crónicas. En el momento actual, se dispone del tratamiento con hormona del crecimiento (HC) para pacientes con deficiencia de HC, síndrome de Ullrich-Turner, insuficiencia renal crónica, pequeños para la edad gestacional y síndrome de Prader-Willi. Hasta la fecha, la indicación del tratamiento con HC para la estatura baja idiopática está sólo aprobada en EE.UU. Los datos de la talla adulta indican que los pacientes con deficiencia de HC documentada alcanzan una talla adulta dentro de su margen de tallas de referencia. Para todas las demás indicaciones se ha documentado una mejoría estadísticamente significativa de la talla adulta. En el seguimiento a largo plazo de estos pacientes debe demostrarse no sólo una mejoría estadísticamente significativa sino también una mejoría clínicamente significativa de la talla adulta. En función de los resultados, podrían tener que reconsiderarse algunas de las indicaciones del tratamiento con HC.
Factors Affecting Physicians’ Practices Related to Helicobacter pylori Infection: Effect of Experience and Mode of Practice
Authors: Yee Yuk Kei , Cheung Ting Kin , Gu Qing , Chan Pierre , But David , Hung Ivan F.N. , Chan Chi Kuen , Yuen Man Fung , Wong Benjamin C.Y.
Published: October 2008

Background: Studies found that guidelines on the management of Helicobacter pylori were not always followed in clinical practice. This study investigated factors that were responsible for the deviation. Methods: A cross-sectional survey using a structured self-administered questionnaire was used to ask physicians whether they would offer testing and treatment for H. pylori infection in different clinical scenarios. Results: 170 medical practitioners completed the questionnaires. Respondents in the private sector were significantly more likely to test and treat than those in the public sector for patients with a history of peptic ulcer, gastric cancer or no symptom (p = 0.018, <0.001 and 0.041, respectively). Significant differences in practice were noted amongst practitioners of different specialty and seniority, but not qualification. Medical practitioners in the private sector complied with the guidelines significantly better than those in the public sector (p = 0.002) and so did senior practitioners compared with junior practitioners (p < 0.001). The specialty and qualification of the respondents, however, did not have a significant effect. Conclusion: There were significant differences in the management of H. pylori amongst medical practitioners from the private and public sectors and amongst senior and junior practitioners. Published guidelines were not completely followed. Further educational campaigns are needed.