On the negative hydrogen ion and its absorption coefficient

The continuous absorption coefficient of the negative hydrogen ion is discussed from the point of view of the sum rules, and it is shown that the absorption coefficient to the red of 5000 A is predominantly governed by the wave-function of the ground state of H- at distances of the order of five times the Bohr radius from the center. It appears that the wave-functions for H- now in use are not sufficiently accurate at these distances to provide reliable values for the absorption coefficient beyond 5000 A, Further, some objective criteria are stated which should enable the reliability of a given absorption curve to be tested

Weaving of UML sequence diagrams using STAIRS

In this report we explore aspect-oriented modeling for UML 2.0 sequence diagrams. We ensure that the aspect weaving is semantics-based by using a formal trace model for sequence diagrams. A major challenge is to handle unbounded loops which produce infinite traces. We establish a systematic way to permutate and rewrite the original loop definition so that the weaving in many typical cases can be performed on a finite structure. We prove that it is always sufficient to consider a loop with upper bound relative to the pointcut definition to discover if the loop has infinitely repeating matches. A running example illustrates the approach and a prototype weaving tool is being implemented

Proteinase-activated receptor-2: two potential inflammatory mediators of the gastrointestinal tract in Atlantic salmon

Proteinase-activated receptor 2 (PAR-2), activated by trypsin and other serine proteinases, is a key initiator of inflammatory responses in the intestine of mammals. Atlantic salmon fed diets with standard qualities of soybean meal (SBM) show enteritis of the distal intestine as well as increased activity of trypsin in both luminal contents and wall tissue. Luminal trypsin activity may possibly be involved in immune related disorders of the intestine also in Atlantic salmon via activation of PAR 2. In the present study our aim was to investigate if PAR-2 play a role in SBM induced enteritis. We performed multiple alignments based on nucleic acid sequences of PAR-2 from various animals available from public databases, and designed primers for use in cloning of the Atlantic salmon PAR-2 transcript. We further cloned and characterized the full length sequence of Atlantic salmon PAR-2 and investigated the expression in both early and chronic stages of SBM induced enteropathy. Two full length versions of PAR-2 cDNA were identified and termed PAR-2a and PAR-2b. Expression of the two PAR-2 transcripts was detected in all 18 tissues examined, but most extensively in the intestine and gills. A significant up-regulation in the distal intestine was observed for the PAR-2a transcript after 1 day feeding diets containing SBM. After 3 weeks of feeding, PAR-2a was down-regulated compared to the fish fed control diets. These findings may indicate that PAR-2a participates in inflammatory responses in both the early and later stages of the SBM enteropathy. In the chronic stages of the enteropathy, down-regulation of PAR-2a may indicate a possible desensitization of the PAR-2a receptor. Expression of PAR-2b was not altered in the first 7 days of SBM feeding, but a significant up regulation was observed after 3 weeks, suggesting a putative role in chronic stages of SBM induced enteritis. The expression differences of the two PAR-2 transcripts in the feed trials may indicate that they have different roles in the SBM induced enteritis

Consistent changes in the intestinal microbiota of Atlantic salmon fed insect meal diets

Background Being part of fish's natural diets, insects have become a practical alternative feed ingredient for aquaculture. While nutritional values of insects have been extensively studied in various fish species, their impact on the fish microbiota remains to be fully explored. In an 8-week freshwater feeding trial, Atlantic salmon (Salmo salar) were fed either a commercially relevant reference diet or an insect meal diet wherein black soldier fly (Hermetia illucens) larvae meal comprised 60% of total ingredients. Microbiota of digesta and mucosa origin from the proximal and distal intestine were collected and profiled along with feed and water samples. Results The insect meal diet markedly modulated the salmon intestinal microbiota. Salmon fed the insect meal diet showed similar or lower alpha-diversity indices in the digesta but higher alpha-diversity indices in the mucosa. A group of bacterial genera, dominated by members of the Bacillaceae family, was enriched in salmon fed the insect meal diet, which confirms our previous findings in a seawater feeding trial. We also found that microbiota in the intestine closely resembled that of the feeds but was distinct from the water microbiota. Notably, bacterial genera associated with the diet effects were also present in the feeds. Conclusions We conclude that salmon fed the insect meal diets show consistent changes in the intestinal microbiota. The next challenge is to evaluate the extent to which these alterations are attributable to feed microbiota and dietary nutrients, and what these changes mean for fish physiology and health.publishedVersio

Convective quenching of stellar pulsations

Context: we study the convection-pulsation coupling that occurs in cold Cepheids close to the red edge of the classical instability strip. In these stars, the surface convective zone is supposed to stabilise the radial oscillations excited by the kappa-mechanism. Aims: we study the influence of the convective motions onto the amplitude and the nonlinear saturation of acoustic modes excited by kappa-mechanism. We are interested in determining the physical conditions needed to lead to a quenching of oscillations by convection. Methods: we compute two-dimensional nonlinear simulations (DNS) of the convection-pulsation coupling, in which the oscillations are sustained by a continuous physical process: the kappa-mechanism. Thanks to both a frequential analysis and a projection of the physical fields onto an acoustic subspace, we study how the convective motions affect the unstable radial oscillations. Results: depending on the initial physical conditions, two main behaviours are obtained: (i) either the unstable fundamental acoustic mode has a large amplitude, carries the bulk of the kinetic energy and shows a nonlinear saturation similar to the purely radiative case; (ii) or the convective motions affect significantly the mode amplitude that remains very weak. In this second case, convection is quenching the acoustic oscillations. We interpret these discrepancies in terms of the difference in density contrast: larger stratification leads to smaller convective plumes that do not affect much the purely radial modes, while large-scale vortices may quench the oscillations.Comment: 15 pages, 17 figures, 3 tables, accepted for publication in A&

Effect of diets containing a purified soybean trypsin inhibitor on growth performance, digestive proteases and intestinal histology in juvenile sea bream (Sparus aurata L.)

Juvenile sea bream were fed on diets containing 0.0, 2.0 or 4.0 g/kg of a soybean trypsin inhibitor (SBTI) for 30 days. The growth performance, total protease activity and intestinal histology were studied after 0,15 and 30 days of dietary treatment. No signi¢cant di¡erences were found in the weight gain, speci¢c growth rate (SGR) and feed conversion rate in fish fed on inhibitor-supplemented diets when compared with those fed on an inhibitor-free diet. Only the SGR at day 15 decreased signi¢cantly with protease inhibitor inclusion, although this effect was not observed at day 30. In relation to proteolytic activity at day 15, the total protease activity in the distal intestine decreased in ¢sh fed on inhibitor-supplemented diets. Zymograms of these extracts showed that the SBTI reduced the intensity of some proteolytic fractions in the distal intestine. A noticeable reduction in the protease activity of the intestinal content in fish fed onthe highest level of soybean inhibitor (4.0 g/kg) was also observed. However, at day 30, the inhibition e¡ect on these active bands was not detected, and the total protease activity was similar to that in ¢sh fed on an inhibitor-free diet. Histological examination revealed no perceptible differences in the intestinal structure between any of the diet groups. In addition, all ¢shweremaintained under experimentation for 10 more days and fed on an inhibitor-free diet to determine whether the possible effects caused by the protease inhibitor could be reverted.The administration of SBTI-supplemented diets did not affect sea bream growth performance or intestine histology after 30 days, and only a decrease in the total alkaline protease activity was found at day 15

A reusable observer pattern implementation using package templates

This is the authors ' version of the work. It is posted here by permission of ACM for your personal use

Optimization of the Balance between Protein, Lipid and Carbohydrate in Diets for Lumpfish (Cyclopterus lumpus)

The aim of this study was to investigate how the dietary balance between protein, lipid, and carbohydrate affects growth, welfare, and health with focus on immune responses, in lumpfish of body weight ranges 1.7-10 g and 15-50 g. A three-component mixture design, with simultaneous variation of the three macronutrients was applied. Growth, tissue and plasma nutrient composition, welfare, cataract frequency, and immune responses in leukocytes isolated from the fish head kidney were studied. Most responses were linear and driven by dietary lipid level, with minor effects of carbohydrate and protein. The growth in 1.7-10 g fish followed a special cubic model with no clear optimum. The fastest growth in the 15-50 g fish was obtained with the diet containing 55% protein, 17% fat, and 6% carbohydrate. The high dietary levels of lipid also gave high lipid levels in the tissues and a trend of improved welfare score, but there were no effects on cataract. The diets with minimum and maximum protein gave suboptimal immune responses in isolated head kidney cells of the 15-50 g fish, while the fastest growing fish showed normal immune responses. We propose that diets for lumpfish from 10-50 g body weight should contain approximately 55% protein, minimum 10% lipid, and maximum 10% carbohydrate. These diets will also be suitable for lumpfish of 1.7-10 g.publishedVersio