Microbial Composition before and after Conservation of Grass-Dominated Haylage Harvested Early,Middle, and Late in the Season

Haylage for horses is often harvested in late plant maturity, which could be associated with an increased risk of impaired hygienic quality in the forage and short aerobic storage stability after bale opening, but knowledge in this area is scant. An experiment was conducted in which the microbial composition was analyzed before and after conservation of primary growth haylage harvested early (June), middle (July), and late (August) in the season during 1 year. The counts of yeast, enterobacteria, and lactic acid bacteria (LAB) in preconserved herbage increased with the advancing harvest time (P ≤ .02). After conservation, the August haylage had increased counts of enterobacteria (log 4.3 colony-forming unit [CFU]/g) and LAB (log 6.5 CFU/g), compared with the June and July haylage (log ≤1.7 CFU/g for enterobacteria and ≤5.7 CFU/g for LAB, P < .001). The yeast counts were the lowest in the June haylage (log 5.0 CFU/g) compared with the July and August haylage (log ≥6.3 CFU/g, P < .001). After conservation, the mold counts were lower in the June haylage and greater in the August haylage (P = .01). In the preconserved herbage, Cladosporium cladosporioides was the most common mold species in June but Fusarium poae was in July, and Mucor fragilis in August. After conservation, Penicillium carneum was the only species found in the June haylage, with M. circinelloides most frequently found in the July haylage and M. hiemalis and M. circinelloides found at similar frequencies in the August haylage. An advanced harvest time resulted in greater counts of enterobacteria, yeast, and LAB and an increased number of mold species in the conserved haylage. The aerobic storage stability of the opened haylage bales measured by temperature was similar among the harvests.     

Fate of C- and N-labelled rhizodeposition of Lolium perenne as function of the distance to the root surface

A greenhouse rhizobox experiment was carried out to quantify the incorporation of ¹³C- and ¹⁵N-labelled rhizodeposits into different soil pools, especially into the rhizosphere microbial biomass, with increasing distances to the root surface of Lolium perenne. Five layers were analysed over 0-4.2 mm distance to an artificial root surface. C and N derived from rhizodeposition were 4.2% of total C and 2.8% of total N in soil at 0-1.0 mm distance and decreased rapidly with increasing distance. Microbial biomass C and N increased significantly towards the roots. At 0-1.0 mm distance microbial biomass C and N accounted for 66% and 29% of C and N derived from rhizodeposition, respectively. These percentages declined with increasing distance to the roots, but were still traceable up to 4.2 mm distance. Only small amounts of root released C and N were found in the 0.05 M K₂SO₄-extractable fraction. Extractable C and N derived from rhizodeposition varied around means of 4% of total C and N derived from rhizodeposition and increased only marginally with increasing distance to the roots. C derived from rhizodeposition in the non-extractable soil organic matter increased from 65 to 89% of total C derived from rhizodeposition at 0-3.4 mm distance. Conversely, microbial biomass C derived from rhizodeposition decreased from 33 to 4%. N derived from rhizodeposition in the non-extractable soil organic matter increased from 61 to 79% of total N derived from rhizodeposition at 0-2.6 mm distance, followed by a decline to roughly 55% in the two outer layers. Microbial biomass N decreased from 37 to 16% at 0-2.6 mm distance, followed by an increase to roughly 41% in the two outer layers. The C/N ratio of total C and N derived from rhizodeposition as well as that of extractable C and N derived from rhizodeposition increased with increasing distance to the roots to values above 30. In contrast, the C/N ratio of incorporated rhizodeposition C and N into the microbial biomass decreased to values less than 5 at 2.6-4.2 mm distance. The data indicate differential microbial response to C and N derived from rhizodeposition at a high spatial resolution from the root surface. The turnover of C and N derived from rhizodeposition in the rhizosphere as a function of the distance to the root surface is discussed.     

A High-Temperature Electrical Conduction Mechanism in the Lower Mantle Phase (Mg,Fe)1-xO

Measurements of electrical conductivity at high pressure and temperature were taken on the lower mantle phase magnesiowustite with varying Fe3+ content. Although previous measurements at atmospheric pressure suggest Fe2+-Fe3+ hopping (small polaron) as the dominant conductivity mechanism, the present experiments show a change in charge transport mechanism with temperature. The lower temperature measurements are consistent with small polaron conduction, but at higher temperatures, which are more applicable to the lower mantle, a large polaron mechanism is suggested. Because these mechanisms have different temperature and compositional dependencies, this transition has important implications for extrapolation to mantle conditions.     

Root and aerial infections of Chamaecyparis lawsoniana by Phytophthora lateralis: a new threat for European countries

Phytophthora lateralis has been isolated from root and collar lesions in Port‐Orford Cedar (POC) trees (Chamaecyparis lawsoniana) in north‐western France (Brittany). These trees, planted in hedgerows, displayed symptoms similar to the typical symptoms of POC root disease. Until now, the disease has been found outside of the nurseries only in western North America. Aerial symptoms, not associated with root or collar infections, were also observed, and P. lateralis was isolated from branch lesions. Similar symptoms were previously observed only in one POC root disease site, located in the Pacific coast of Oregon where climatic conditions are similar to those occurring in Brittany. The reported aetiology as well as the morphological characteristics (deciduous sporangia) of P. lateralis suggests that this species could be air‐dispersed, as described for P. ramorum, a closely related species. This outbreak of P. lateralis in Brittany in farming landscapes associated with the aerial spread of this pathogen represents a new threat for European countries.     

Analysis of ethyl carbamate in wines using solid-phase extraction and multidimensional gas chromatography/mass spectrometry

The method describes a rapid and accurate procedure for the analysis of ethyl carbamate in wines. The separation of the ethyl carbamate (EC), the target analyte, from alcohol and the sample matrix is a challenge to many analytical chemists. After alcohol removal from the sample, EC was extracted and concentrated by solid-phase extraction. For analysis of EC, large-volume injection on a programmable temperature vaporization (PTV) inlet was used followed by multidimensional gas chromatography/mass spectrometry (MDGC/MS) using electron-impact ionization (EI). For quantitation, the ratio of ions produced during EI at m/z 62 (EC) and 64 (isotopically labeled EC) was monitored. The use of solid-phase extraction and MDGC/MS removes the majority of the matrix interference encountered in other methods. A linear dynamic range was established from 0.387 to 1160 ng/mL, with a limit of detection at 0.1 ng/mL and limit of quantitation at 1 ng/mL.     

Prediction of serum ionized calcium concentration by use of serum total calcium concentration in dogs

OBJECTIVE: To determine whether total serum calcium (tCa) or adjusted tCa concentrations accurately predict ionized calcium (iCa) status in dogs. SAMPLE POPULATION: 1,633 canine serum samples. PROCEDURE: The tCa concentration was adjusted for total protein (TP) or albumin concentration by use of published equations. Correlations between iCa and tCa or adjusted tCa, tCa and TP, and tCa and albumin were calculated. Diagnostic discordance between tCa or adjusted tCa and iCa was determined. Diagnostic discordance in predicting iCa was also determined for 490 dogs with chronic renal failure (CRF). Sensitivity, specificity, positive and negative predictive values, and positive and negative diagnostic likelihood ratios were calculated for tCa, tCa adjusted forTP, and tCa adjusted for albumin. RESULTS: Diagnostic discordance was 27% when tCa concentration was used to predict iCa status. Use of adjusted tCa increased diagnostic discordance to approximately 37% for all dogs and 55% for dogs with CRF. Positive predictive value and positive diagnostic likelihood ratios were poor when tCa concentration was used to predict iCa status. The tCa concentration overestimated normocalcemia and underestimated hypocalcemia. Adjusted tCa overestimated hypercalcemia and underestimated hypocalcemia. CONCLUSIONS AND CLINICAL RELEVANCE: Adjusted tCa or tCa concentrations are unacceptable for predicting iCa status in dogs. Use of adjustment equations is not recommended. Direct measurement of iCa concentration is necessary for accurate assessment of calcium status. Use of tCa or adjusted tCa concentrations to predict iCa status in dogs could cause serious mistakes in diagnosis and case management, especially in dogs with CRF.     

Filamentous fungi in wrapped forages determined with different sampling and culturing methods

The use of wrapped forage bales with high dry‐matter (DM) content implies risk of fungal growth inside the wrapping, and impaired feed quality. Since fungi may be unevenly distributed in bales, the method of sampling can influence the outcome of the analysis. Three common sampling methods for detection of fungi in wrapped forage were compared: direct plating of visible mouldy patches on bale surfaces (Method I), direct plating of pieces of foliage from drilled core samples (Method II) and quantitative analysis dilution series of drilled core samples (Method III). All samples were cultured on two media at two temperatures. Samples were collected from 124 farms in Sweden and Norway. Using Methods I, II and III, fungi were detected on 52%, 77% and 56% of the farms respectively. Fifty‐two fungal species were identified using a combination of culturing and molecular methods. The most predominant species were Arthrinium spp., found on 55% of the farms, followed by Penicillium roqueforti at 48% of the farms. Incubation at 25°C resulted in higher numbers of all genera, except Aspergillus, compared to incubation at 37°C. The different methods of sampling and culturing did not identify the same fungal species within the same bale. Analysing one bale per farm resulted in detection of less than half the number of species compared to analysing three bales. Of the sampling and culturing methods compared, direct plating of drilled core samples cultivated at malt extract agar at 25°C performed best in terms of qualitative analysis of fungi species.     

Unitary control in quantum ensembles: maximizing signal intensity in coherent spectroscopy

Experiments in coherent magnetic resonance, microwave, and optical spectroscopy control quantum-mechanical ensembles by guiding them from initial states toward target states by unitary transformation. Often, the coherences detected as signals are represented by a non-Hermitian operator. Hence, spectroscopic experiments, such as those used in nuclear magnetic resonance, correspond to unitary transformations between operators that in general are not Hermitian. A gradient-based systematic procedure for optimizing these transformations is described that finds the largest projection of a transformed initial operator onto the target operator and, thus, the maximum spectroscopic signal. This method can also be used in applied mathematics and control theory.