A multi-scale approach to determine the REV in complex carbonate rocks

Complex porous carbonates display heterogeneity at different scales, influencing their reservoir properties (e.g. porosity) especially since different porosity types may exist on different spatial scales. This requires a quantitative geometric description of the complex (micro)structure of the rocks. Modern computer tomography techniques permit acquiring detailed information concerning the porosity network at different scales. These datasets allow evolvement to a more objective pore classification based on mathematical parameters. However computational limitations in complex reservoir models do not allow incorporating heterogeneities on small scales (e.g. sub-meter scale) in full-field reservoir simulations [Nordahl and Ringrose, 2008]. The suggested workflow allows characterizing different porosity networks in travertine rocks as well as establishing confidence intervals regarding the Representative Elementary Volume (REV) of these samples. The results of this study prove that one has to be very critical when determining the REV of heterogeneous complex carbonate rocks, since they are influenced by both resolution and size of the dataset

Milk fatty acid composition and associated rumen lipolysis and fatty acid hydrogenation when feeding forages from intensively managed or semi-natural grasslands

In order to evaluate the effect of replacing intensive forage by semi-natural grassland products on rumen lipid metabolism and milk fatty acid composition, four lactating and rumen canulated Holstein cows were used in a 4×4 Latin square design. Four different diets were fed: diet 100 IM - 100% intensively managed silage (IM), diet 20 SPP - 80% IM plus 20% semi-natural but species poor silage (SPP), diet 60 SPP - 40% IM plus 60% SPP and diet 60 SPR - 40% IM plus 60% semi-natural species rich silage (SPR). The silages showed significant differences in total fat content and in proportions of C18:2 n-6 and C18:3 n-3. Despite the reduced dietary supply of C18:3 n-3 with diets 60 SPP and 60 SPR, differences in milk C18:3 n-3 were small, suggesting higher recoveries of C18:3 n-3. Presumably, the latter are related to a higher transfer efficiency of C18:3 n-3 from the duodenum to the mammary gland, since rumen biohydrogenation, estimated from rumen pool size and first order rumen clearance kinetics, were similar among diets. CLA c9t11 in milk from cows fed diet 60 SPR were almost doubled compared to feeding one of the other diets. This has been related to the partial inhibition of rumen biohydrogenation of C18:3 n-3 and/or C18:2 n-6, as suggested by the increased proportions of hydrogenation isomers and reduced stearic acid proportions in rumen pool samples. In conclusion, the results suggest that the use of semi-natural grasslands in the diet of the animals reduce to some extent complete rumen biohydrogenation, which leads to an increase in milk CLA

Effect of induction of subacute ruminal acidosis on milk fat profile and rumen parameters

High-concentrate diets can lead to subacute ruminal acidosis and are known to result in changes of the ruminal fermentation pattern and mammary secretion of fatty acids. The objective of this paper is to describe modifications in milk fatty acid proportions, particularly odd- and branched-chain fatty acids and rumen biohydrogenation intermediates, associated with rumen parameters during a 6-wk subacute ruminal acidosis induction protocol with 12 ruminally fistulated multiparous cows. The protocol involved a weekly gradual replacement of a standard dairy concentrate with a wheat-based concentrate (610 g of wheat/kg of concentrate) during the first 5 wk and an increase in the total amount of concentrate in wk 6. Before the end of induction wk 6, cows were switched to a control diet because 7 cows showed signs of sickness. The pH was measured continuously by an indwelling pH probe. Milk and rumen samples were taken on d 2 and 7 of each week. Data were analyzed using a linear mixed model and by principal component analysis. A pH decrease occurred after the first concentrate switch but rumen parameters returned to the original values and remained stable until wk 5. In wk 5 and 6, rumen pH values were indicative of increasing acidotic conditions. After switching to the control diet in wk 6; rumen pH values rapidly achieved normal values. Odd- and branched-chain fatty acids and C18:1 trans-10 increased with increasing amount of concentrate in the diet, whereas C18:1 trans-11 decreased. Four fatty acids [C18:1 trans-10, C15:0 and C17:0+C17:1 cis-9 (negative loadings), and iso C14:0 (positive loading)] largely correlated with the first principal component (PC1); with cows spread along the PC1 axis. The first 4 wk of the induction experiment showed variation across the second principal component (PC2) only, with high loadings of anteiso C13:0 (negative loading) and C18:2 cis-9,trans-11 and C18:1 trans-11 (positive loadings). Weeks 5 and 6 deviated from PC2 and tended toward the negative PC1 axis. A discriminant analysis using a stepwise approach indicated the main fatty acids discriminating between the control and acidotic samples as iso C13:0, iso C16:0, and C18:2 cis-9. trans-11 rather than milk fat content. or C18:1 trans-10; which have been used before as indicators of acidosis. This shows that specific milk fatty acids have potential in discriminating acidotic cases

Influence of damaging and wilting red clover on lipid metabolism during ensiling and in vitro rumen incubation

This paper describes the relationship between protein-bound phenols in red clover, induced by different degrees of damaging before wilting and varying wilting duration, and in silo lipid metabolism. The ultimate effect of these changes on rumen biohydrogenation is the second focus of this paper For this experiment, red clover, damaged to different degrees (not damaged (ND), crushing or frozen/thawing (FT)) before wilting (4 or 24 h) was ensiled. Different degrees of damaging and wilting duration lead to differences in polyphenol oxidase (PPO) activity, measured as increase in protein-bound phenols. Treatment effects on fatty acid (FA) content and composition, lipid fractions (free FAs, membrane lipids (ML) and neutral fraction) and lipolysis were further studied in the silage. In FT, red clover lipolysis was markedly lower in the first days after ensiling, but this largely disappeared after 60 days of ensiling, regardless of wilting duration. This suggests an inhibition of plant lipases in FT silages. After 60 days of ensiling no differences in lipid fractions could be found between any of the treatments and differences in lipolysis were caused by reduced FA proportions in ML of wilted FT red clover Fresh, wilted (24 h) after damaging (ND or FT) and ensiled (4 or 60 days; wilted 24 h; ND or FT) red clover were also incubated in rumen fluid to study the biohydrogenation of C18:3n-3 and C18:2n-6 in vitro. Silages (both 60 days and to a lower degree 4 days) showed a lower biohydrogenation compared with fresh and wilted forages, regardless of damaging. This suggests that lipids in ensiled red clover were more protected, but this protection was not enhanced by a higher amount of protein-bound phenols in wilted FT compared with ND red clover The reduction of rumen microbial biohydrogenation with duration of red clover ensiling seems in contrast to what is expected, namely a higher biohydrogenation when a higher amount of FFA is present. This merits further investigation in relation to strategies to activate PPO toward the embedding of lipids in phenol protein complexes

Migrating medical communications software to a multi-tenant cloud environment

The rise of cloud computing has paved the way for many new applications. Many of these new cloud applications are also multi-tenant, ensuring multiple end users can make use of the same application instance. While these technologies make it possible to create many new applications, many legacy applications can also benefit from the added flexibility and cost-savings of cloud computing and multi-tenancy. In this paper, we describe the steps required to migrate a. NET-based medical communications application to the Windows Azure public cloud environment, and the steps required to add multi-tenancy to the application. We then discuss the advantages and disadvantages of our migration approach. We found that the migration to the cloud itself requires only a limited amount of changes to the application, but that this also limited the benefits, as individual instances would only be partially used. Adding multi-tenancy requires more changes, but when this is done, it has the potential to greatly reduce the cost of running the application

The effect of N-fertilisation rate or inclusion of red clover to timothy leys on fatty acid composition in milk of dairy cows fed a commercial silage:concentrate ratio

The aim of this experiment was to, under typical Swedish production conditions, evaluate the effects of grass silages subjected to different N-fertilisation regimes fed to dairy cows on the fatty acid (FA) composition of their milk, and to compare the grass silages in this respect to red clover-dominated silage. Grass silages made from first year Phleum pratense L. leys subjected to three N-fertilisation regimes (30, 90 and 120 kg N/ha, designated G-30, G-90 and G-120, respectively) and a mixed red clover grass silage (Trifolium pratense L. and P. pratense L; 60/40 on dry matter (DM) basis, designated RC G) were produced. The experiment was conducted as a change-over design, including 24 primiparous and multiparous dairy cows of the Swedish Red breed, each of which was allocated to three of the four diets. The cows were offered 11 kg DM of silage and 7 kg concentrates. The silages had similar DM and energy concentrations. The CP concentration increased with increase in N-fertilisation level. There was a linear increase in DM intake of the different silages with increased N fertilisation. There were also differences in concentrations of both individual and total FAs amongst silages. The daily milk production (kg/day) did not significantly differ between treatments, but G-30 silage resulted in higher concentrations of 18:2n-6 in the milk compared with the other two grass silages. The highest concentrations of 18:3n-3 and cis-9, trans-11 18:2 were found in milk from cows offered the RC G silage. The G-30 diet resulted in higher concentration of 18:2n-6 and the same concentration of 18:3n-3 in the milk as the other grass silages, despite lower intake levels of these FAs. The apparent recoveries of 18:3n-3 from feed to milk were 5.74%, 4.27%, 4.10% and 5.31% for G-30, G-90, G-120 and RC G, respectively. A higher recovery when red clover is included in the diet confirms previous reports. The higher apparent recovery of 18:3n-3 on the G-30 treatment may be related to the lower silage DM intake, which led to a higher relative proportion of ingested FAs originating from concentrates compared with the G-90 and G-120 diets. With the rates and types of concentrates used in this study, the achieved differences in FA composition among the silages were not enough to influence the concentrations of unsaturated FAs in milk

The Role of Maternal Thyroid Hormones in Avian Embryonic Development

During avian embryonic development, thyroid hormones (THs) coordinate the expression of a multitude of genes thereby ensuring that the correct sequence of cell proliferation, differentiation and maturation is followed in each tissue and organ. Although THs are needed from the start of development, the embryonic thyroid gland only matures around mid-incubation in precocial birds and around hatching in altricial species. Therefore, maternal THs deposited in the egg yolk play an essential role in embryonic development. They are taken up by the embryo throughout its development, from the first day till hatching, and expression of TH regulators such as distributor proteins, transporters, and deiodinases in the yolk sac membrane provide the tools for selective metabolism and transport starting from this level. TH receptors and regulators of local TH availability are expressed in avian embryos in a dynamic and tissue/cell-specific pattern from the first stages studied, as shown in detail in chicken. Maternal hyperthyroidism via TH supplementation as well as injection of THs into the egg yolk increase TH content in embryonic tissues while induction of maternal hypothyroidism by goitrogen treatment results in a decrease. Both increase and decrease of maternal TH availability were shown to alter gene expression in early chicken embryos. Knockdown of the specific TH transporter monocarboxylate transporter 8 at early stages in chicken cerebellum, optic tectum, or retina allowed to reduce local TH availability, interfering with gene expression and confirming that development of the central nervous system (CNS) is highly dependent on maternal THs. While some of the effects on cell proliferation, migration and differentiation seem to be transient, others result in persistent defects in CNS structure. In addition, a number of studies in both precocial and altricial birds showed that injection of THs into the yolk at the start of incubation influences a number of parameters in posthatch performance and fitness. In conclusion, the data presently available clearly indicate that maternal THs play an important role in avian embryonic development, but how exactly their influence on cellular and molecular processes in the embryo is linked to posthatch fitness needs to be further explored

Effects of nematic fluctuations on the elastic properties of iron arsenide superconductors

We demonstrate that the changes in the elastic properties of the FeAs systems, as seen in our resonant ultrasound spectroscopy data, can be naturally understood in terms of fluctuations of emerging nematic degrees of freedom. Both the softening of the lattice in the normal, tetragonal phase as well as its hardening in the superconducting phase are consistently described by our model. Our results confirm the view that structural order is induced by magnetic fluctuations.Comment: revised version with changed title accepted for publication in PR

Lipid peroxidation in tobacco leaves treated with the elicitor cryptogein: evaluation by high-temperature thermoluminescence emission and chlorophyll fluorescence

AbstractTreatment of excised tobacco leaves with the fungal elicitor cryptogein progressively induced lipid peroxidation. In a first step, evidence was provided by the accumulation of thiobarbituric acid reactive substances (TBARS) and in a second step, the process was monitored for a 26 h period by high-temperature thermoluminescence (TL) emission, showing a close correlationship with the TBARS data. Differences in the temperature-associated F0 rise (constant fluorescence) and in fluorescence emission spectra point to a progressive destabilization of the thylakoid membrane, especially affecting Photosystem II (PS II). In parallel, the PS II quantum efficiency ΔF / Fm and the Fv / Fm ratio of chlorophyll fluorescence induction decreased significantly over the 24 h period