Effect of the methodology on circulating peptides determination and consequences on net flux measurements across the gastrointestinal tract of sheep.     

L Bernard  C F R Backwell  D Rémond  D Wilson  L A Bruce  V Buchan  J C MacRae 《Archives of Animal Nutrition》2002,56(1):13-21

Two methodologies for the measurement of peptide amino acids (PAA) in blood were compared to evaluate their effects on the measurement of the net flux of peptides across the gastrointestinal tract of sheep. These methods consisted of a chemical deproteinization of blood samples with sulfosalicylic acid (1.6 M, 0.1 ml for 1 ml of sample) or perchloric acid (1 M, 1 ml for 1 ml of sample) followed by ultrafiltration through a 3,000-Da cut-off filter (SSA + UF3 kD) or gel filtration through a Sephadex G-15 column (1,500-Da cut-off filter; PCA + G-15), respectively, prior to PAA analysis. Peptide concentrations as determined by amino acid concentrations before and after hydrolysis of samples were slightly greater with the SSA + UF3 kD (991 microM) than with the PCA + G-15 (605 microM) methodology. However, both methodologies gave similar net portal-drained viscera flux data in sheep fed on alfalfa pellets with histidine as the only significant uptake of peptide amino acid.  相似文献   

Letters to the Editor ◆ Lettres À La Rédaction: Ethics on the decline — A reply          下载免费PDF全文

Bernard E. Rollin 《The Canadian veterinary journal. La revue veterinaire canadienne》1997,38(11):677

  相似文献   

Remittances sent by a growing altruistic diaspora: How do they grow over time?     

Bernard Poirine 《Asia Pacific viewpoint》2006,47(1):93-108

Abstract: This paper investigates theoretically the time pattern of remittances sent home by a growing diaspora of emigrants who are motivated by altruism rather than pure self‐interest. Migrants are assumed to care about the consumption of home‐resident family members as well as their own welfare. Hence, remittance effort will depend upon the ratios of per capita income and income growth rates between the host country and the home country. Effort will depend also on the number of emigrants sending back remittances to each home‐resident household. In general, the effect of remittances is to sustain growth of consumption per capita in the home country above the growth rate of per capita GDP. A priori, there is no necessary tendency for remittance effort to rise or fall over time. Falling remittance amounts per migrant may occur as the diaspora grows relative to the home population, but should not be treated as evidence of so‐called ‘remittance fatigue’. A number of feasible scenarios are traced out, and some opportunities are identified to use statistical tests to adjudicate between self‐interest and altruism as motives for sending remittances.  相似文献   

Metaphase-I analysis of a Triticum aestivum x T. monococcum hybrid by the C-banding technique     

Juan M. González  Sylvie Bernard  Michel Bernard 《Euphytica》1993,68(3):187-192

Summary The meiotic pairing behaviour at metaphase I of a Triticum aestivum×Triticum monococcum hybrid has been studied by means of the C-banding technique to ascertain the homology between the chromosomes in the A genome of the two species. The technique allowed the A and B genome chromosomes and the 2D, 3D and 5D chromosomes to be identified. Differences in the level of chromosome pairing in the A genome were noted. The T. monococcum 4A chromosome did not pair with any of the T. aestivum chromosomes in any of the metaphase I cells analysed. Two reciprocal translocations between the 2B and 2D chromosomes on one side and the 2A and 3D on the other side have been identified. The usefulness of the C-banding technique in the study of chromosome homology among species related to wheat is discussed.  相似文献   

Maximum slat width for cooling efficiency of horticultural produce in wooden crates     

Clment Vigneault  Bernard Goyette  Larissa R. de Castro 《Postharvest Biology and Technology》2006,40(3):308-313

The influence of wood package design on airflow distribution was investigated for forced-air cooling using horticultural produce simulators. The position of grooves on the container walls was tested using slat width of 100–200 mm and airflow rates ranging from 0.0005 to 0.003 m³ kg⁻¹ s⁻¹. The package opening configurations were compared based on their impact on the energy added to the system using a methodology previously developed. For this purpose, apples and sweet corns were taken as examples of produce from two different extremes in the respiration activity range. For airflow rates as low as 0.0005 m³ kg⁻¹ s⁻¹one groove at the bottom of the container produced a cooling process more uniform than the other one-groove configurations and even two grooves because of natural convection effect. If packing low respiration rate produce, increasing airflow rate could compromise the process energy efficiency because of air circulation obstruction for less vented containers. For high respiration rate produce enlarging open area above 2.4% would be recommended rather than increasing airflow rate to enhance cooling energy efficiency.  相似文献   

Genetics of resistance to 3 isolates of Ascochyta fabae on Faba bean (Vicia faba L.) in controlled conditions     

Mohamed Kharrat  Joël Le Guen  Bernard Tivoli 《Euphytica》2006,151(1):49-61

Summary Genetics of resistance to Ascochyta fabae Speg. in Vicia faba L. was studied with a final objective to develop resistant faba bean varieties to Ascochyta blight. The study was conducted separately on 3 single spore isolates (AF10-2 and AF13-2 from Tunisia and AF4-3 from France) and belonging to different groups of virulence (GV1 and GV2). Important general combining ability (GCA) effects were found especially with isolates AF10-2 and AF4-3. Specific combining ability (SCA), although significant for the 3 isolates, was important only with AF13 -2, but less important than GCA. Additive gene effects were predominant to non-additive effects. Lines 29H and A8817 transmitted to their progenies resistance to the 3 isolates, whereas 14–12 and 19TB conferred resistance to their progenies only with isolates AF13-2 and AF4-3, respectively. In the material studied, resistance was generally controlled by dominant genes but also could be attributed to recessive genes although less frequent. Analysis of segregation in the F2 of 2 crosses between the resistant lines (A8817 and 29H) and the susceptible line (14–12) with isolate AF4-3 revealed dominant monogenic control at the level of leaves in the 2 resistant lines and, in addition, a recessive gene controlling resistance of stems. Non-allelic interactions were occasionally manifested and their origin appeared to be due to line 19TB. A recurrent selection scheme was proposed with the objective to develop improved open-pollination populations and synthetic varieties responding to the objective of the national Tunisian research programme on faba bean.  相似文献   

Anisotropy of wood vibrational properties: dependence on grain angle and review of literature data   总被引：1，自引：1，他引：0  

Iris Brémaud  Joseph Gril  Bernard Thibaut 《Wood Science and Technology》2011,45(4):735-754

The anisotropy of vibrational properties influences the acoustic behaviour of wooden pieces and their dependence on grain angle (GA). As most pieces of wood include some GA, either for technological reasons or due to grain deviations inside trunks, predicting its repercussions would be useful. This paper aims at evaluating the variability in the anisotropy of wood vibrational properties and analysing resulting trends as a function of orientation. GA dependence is described by a model based on transformation formulas applied to complex compliances, and literature data on anisotropic vibrational properties are reviewed. Ranges of variability, as well as representative sets of viscoelastic anisotropic parameters, are defined for mean hardwoods and softwoods and for contrasted wood types. GA-dependence calculations are in close agreement with published experimental results and allow comparing the sensitivity of different woods to GA. Calculated trends in damping coefficient (tanδ) and in specific modulus of elasticity (E′/ρ) allow reconstructing the general tanδ-E′/ρ statistical relationships previously reported. Trends for woods with different mechanical parameters merge into a single curve if anisotropic ratios (both elastic and of damping) are correlated between them, and with axial properties, as is indicated by the collected data. On the other hand, varying damping coefficient independently results in parallel curves, which coincide with observations on chemically modified woods, either “artificially”, or by natural extractives.  相似文献   

Determinants of annual fluxes of CO₂ and N₂O in long-term no-tillage and conventional tillage systems in northern France   总被引：2，自引：1，他引：2  

Katrien Oorts  Roel Merckx  Eric Grhan  Jrme Labreuche  Bernard Nicolardot 《Soil & Tillage Research》2007,95(1-2):133-148

The greenhouse gases CO₂ and N₂O emissions were quantified in a long-term experiment in northern France, in which no-till (NT) and conventional tillage (CT) had been differentiated during 32 years in plots under a maize–wheat rotation. Continuous CO₂ and periodical N₂O soil emission measurements were performed during two periods: under maize cultivation (April 2003–July 2003) and during the fallow period after wheat harvest (August 2003–March 2004). In order to document the dynamics and importance of these emissions, soil organic C and mineral N, residue decomposition, soil potential for CO₂ emission and climatic data were measured. CO₂ emissions were significantly larger in NT on 53% and in CT on 6% of the days. From April to July 2003 and from November 2003 to March 2004, the cumulated CO₂ emissions did not differ significantly between CT and NT. However, the cumulated CO₂ emissions from August to November 2003 were considerably larger for NT than for CT. Over the entire 331 days of measurement, CT and NT emitted 3160 ± 269 and 4064 ± 138 kg CO₂-C ha⁻¹, respectively. The differences in CO₂ emissions in the two tillage systems resulted from the soil climatic conditions and the amounts and location of crop residues and SOM. A large proportion of the CO₂ emissions in NT over the entire measurement period was probably due to the decomposition of old weathered residues. NT tended to emit more N₂O than CT over the entire measurement period. However differences were statistically significant in only half of the cases due to important variability. N₂O emissions were generally less than 5 g N ha⁻¹ day⁻¹, except for a few dates where emission increased up to 21 g N ha⁻¹ day⁻¹. These N₂O fluxes represented 0.80 ± 0.15 and 1.32 ± 0.52 kg N₂O-N ha⁻¹ year⁻¹ for CT and NT, respectively. Depending on the periods, a large part of the N₂O emissions occurred was probably induced by nitrification, since soil conditions were not favorable for denitrification. Finally, for the period of measurement after 32 years of tillage treatments, the NT system emitted more greenhouses gases (CO₂ and N₂O) to the atmosphere on an annual basis than the CT system.  相似文献   

Near‐infrared spectroscopy can predict the composition of organic matter in soil and litter     

Thomas Terhoeven‐Urselmans  Kerstin Michel  Mirjam Helfrich  Heiner Flessa  Bernard Ludwig 《植物养料与土壤学杂志》2006,169(2):168-174

The usefulness and limitations of near‐infrared reflectance spectroscopy (NIRS) for the assessment of several soil characteristics are still not sufficiently explored. The objective of this study was to evaluate the ability of visible and near‐infrared reflectance (VIS‐NIR) spectroscopy to predict the composition of organic matter in soils and litter. Reflectance spectra of the VIS‐NIR region (400–2500 nm) were recorded for 56 soil and litter samples from agricultural and forest sites. Spectra were used to predict general and biological characteristics of the samples as well as the C composition which was measured by ¹³C‐CPMAS‐NMR spectroscopy. A modified partial least‐square method and cross‐validation were used to develop equations for the different constituents over the whole spectrum (1st to 3rd derivation). Near‐infrared spectroscopy predicted well the C : N ratios, the percentages of O‐alkyl C and alkyl C, the ratio of alkyl C to O‐alkyl C, and the sum of phenolic oxidation products: the ratios of standard deviation of the laboratory results to standard error of cross‐validation (RSC) were greater than 2, the regression coefficients (a) of a linear regression (measured against predicted values) ranged from 0.9 to 1.1, and the correlation coefficients (r) were greater than 0.9. Satisfactorily (0.8 ≤ a ≤ 1.2, r ≥ 0.8, and 1.4 ≤ RSC ≤ 2.0) assessed were the contents of C, N, and production of DOC, the percentages of carbonyl C and aromatic C and the ratio of alkyl C to aromatic C. However, the N‐mineralization rate and the microbial biomass were predicted unsatisfactorily (RSC < 1.4). The good and satisfactory predictions reported above indicate a marked usefulness of NIRS in the assessment of biological and chemical characteristics of soils and litter.  相似文献   

Variability of CO2 and N2O emissions during freeze‐thaw cycles: results of model experiments on undisturbed forest‐soil cores     

Robert Teepe  Bernard Ludwig 《植物养料与土壤学杂志》2004,167(2):153-159

The amounts of N₂O released in periods of alternate freezing and thawing depend on site and freezing conditions, and contribute considerably to the annual N₂O emissions. However, quantitative information on the N₂O emission level of forest soils in freeze‐thaw cycles is scarce, especially with regard to the direct and indirect effect of tree species and the duration of freezing. Our objectives were (i) to quantify the CO₂ and N₂O emissions of three soils under beech which differed in their texture, C and N contents, and humus types in freeze‐thaw cycles, and (ii) to study the effects of the tree species (beech (Fagus sylvatica L.) and spruce (Picea abies (L.) Karst.)) for silty soils from two adjacent sites and the duration of freezing (three and eleven days) on the emissions. Soils were adjusted to a matric potential of –0.5 kPa, and emissions were measured in 3‐hr intervals for 33 days. CO₂ emissions of all soils were similar in the two freeze‐thaw cycles, and followed the temperature course. In contrast, the N₂O emissions during thawing differed considerably. Large N₂O emissions were found on the loamy soil under beech (Loam‐beech) with a maximum N₂O emission of 1200 μg N m^–2 h^–1 and a cumulative emission of 0.15 g N m^–2 in the two thawing periods. However, the sandy soil under beech (Sand‐beech) emitted only 1 mg N₂O‐N m^–2 in the two thawing periods probably because of a low water‐filled pore space of 44 %. The N₂O emissions of the silty soil under beech (Silt‐beech) were small (9 mg N m^–2 in the two thawing periods) with a maximum emission of 150 μg N m^–2 h^–1 while insignificant N₂O emissions were found on the silty soil under spruce (0.2 mg N m^–2 in the two thawing periods). The cumulative N₂O emissions of the short freeze‐thaw cycles were 17 % (Sand‐beech) or 22 % (Loam‐beech, Silt‐beech) less than those of the long freeze‐thaw cycles, but the differences between the emissions of the two periods were not significant (P ≤ 0.05). The results of the study show that the amounts of N₂O emitted in freeze‐thaw cycles vary markedly among different forest soils and that the tree species influence the N₂O thawing emissions in forests considerably due to direct and indirect impacts on soil physical and chemical properties, soil structure, and properties of the humus layer.  相似文献