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The development of Next-Generation Sequencing (NGS) technologies has revolutionized multiple fields of Biology. The ability to sequence DNA and RNA in an automated, parallel and low-cost approach, was key to boost the applicability and acquisition efficiency of omics resources. In this context, the availability of these tools has become indispensable towards our understanding of biodiversity, deepening our knowledge on the distinct complexity levels, from cells to ecosystems. In this study we comprehensively characterised and annotated a whole-body transcriptome of Hediste diversicolor. This annelid worm species belongs to the family Nereididae and inhabits estuarine and lagoon areas on the Atlantic coasts of Europe and North America. Ecologically, this species plays an important role in benthic food webs. The ability of rework sediments through bioturbation activity makes this species essential to the estuarine mechanisms. Here, we used Illumina next-generation sequencing technology, to sequence a total 105 million (M) paired-end (PE) raw reads and produce the first multi-tissue transcriptome assembly of an adult of H. diversicolor. This transcriptome contains 69,335 transcripts with a N50 transcript length of 2,313 bp and a BUSCO gene completeness of 97.7% and 96% (S: 88.2%; D: 7.8%) in Eukaryota and Metazoa lineage-specific profile libraries. Our findings offer a valuable resource for multiple biological studies using this species., This research was partially supported by the ERA-NET BlueBio COFUND Project SIDESTREAM [Grant ID 68], co-funded through national funds provided by FCT [BLUEBIO/0005/2019]; Agencia Estatal de Investigación [PCI2020-111960], NRC – Norwegian Research Council [#311701]. A.G.S. was funded by the Portuguese Foundation for Science and Technology (FCT) under the Grant [SFRH/BD/137935/2018]. Additional strategic funding was provided by FCT [UIDP/04423/2020].

Ballan wrasse (Labrus bergylta) is in the limelight of aquaculture research due to the species role as cleaner fish in salmon aquaculture. A major drawback is that the salmon industry still depends on wild caught fish as there are still many unsolved challenges in ballan wrasse aquaculture, amongst them the determination of egg quality. We measured a range of different egg quality markers on 6 different batches of eggs from ballan wrasse. Additionally, we performed lipidomics on these eggs to test whether their lipid profiles relate to, and can be thereby used as, a predictor for egg quality. We identified relationships between several lipid species and physiological and morphological egg quality markers, and the lipids grouped into two groups. The first group consisted of a diverse blend of 32 lipids, and was positively correlated with size related measures while it was negatively related to measures describing metabolic activity. It consisted of phosphatidylcholines (PC), lysophosphatidylcholine (lysoPC), and triacylglicerids (TAG) and three different sphingomyelins (SM). The second group consisted of 24 lipid species, and showed the inverse pattern, positive relationships with metabolic activity and negative relationships to size related measures. This group of lipid species contained several phosphatidylethanolamines (PE) and free fatty acids. These lipid species may be proposed as key egg quality markers which ultimately can be used by the aquaculture industry to select high quality egg batches in hatcheries.

The use of cleaner fish, such as the ballan wrasse (Labrus bergylta), is important for combatting the sea lice problem in salmonid cage farming. Ballan wrasse is the only wrasse species that is cultivated, though only about 50% of the approx. 3 million ballan wrasse used in 2020 was produced by aquaculture. The major obstacle for large scale cultivation of ballan wrasse is the difficult first feeding phase and a lack of functional feeding protocols. Like most pelagic marine fish larvae, ballan wrasse do not accept inert diets as first feed, and feeding regimes based on rotifers and Artemia (brine shrimps) usually lead to mixed results and are far from being optimal nutrition for the larvae. In a 48-day start feeding experiment, we studied the feasibility of replacing rotifers by an Experimental cirriped diet or copepod nauplii (Acartia tonsa) and replacing Artemia by nauplii of the cirriped Semibalanus balanoides. Later, all treatments received the same formulated diets. We sampled larvae at each feed transition to analyze different response variables such as growth, morphometry, gene expression, lipidomics, histology, and microbiology. We found significant differences in survival rates and growth. Larvae fed copepods as the first diet had significantly higher survival rates than larvae start-fed on either rotifers or small experimental cirripeds, and this pattern was also reflected in early growth and bone development. Gut histology at the end of the experiment (48 days after hatching) showed a more developed intestinal tissue in the larval group fed copepods first and cirripeds as the second diet compared to the other larval groups. Gene expression at day 48 post hatch still revealed pronounced differences between the larval group first fed on rotifers and larvae from the other three feeding regimes which received natural, unenriched diets. Even weeks after receiving the same formulated diets, lipidomics analyses revealed that several lipid species correlated either negatively or positively with larval growth rates or mortality. Our results are a clear indication for nutritional programming, pointing towards the importance the first diet has for the further life of a fish.

Lumpfish (Cyclopterus lumpus) serves an important role as cleaner fish for removing salmon lice in salmon aquaculture. For this use, cultivated lumpfish are preferred over wild-caught fish to avoid overexploitation of natural stocks and provide a stable production of good quality eggs and larvae. To support this, high quality eggs containing the necessary building blocks to support high fertilization success, development into a normal embryo and high hatching success is needed. Ova from wild-caught and captive lumpfish females were collected and assessed to identify how wild and domesticated lumpfish differ in terms of ova lipid profiles, egg and larvae quality. Wild-caught lumpfish displayed higher fertilization and hatching success compared to captive lumpfish, whereas other biological variables like egg size, egg/larvae dry weight and respiration, and larval morphometry, were not significantly different between wild and captive lumpfish. Ova lipid profiles (total lipid, lipid classes, fatty acid composition and lipidomics) can separate egg batches based on their geographic origin of wild-caught females and composition of diets used for captive broodstock (lipid and carbohydrate content). Multivariate statistics were applied to identify lipid markers that can be used to predict the quality of lumpfish ova. Lumpfish ova lipidomic profiles covaried with several biological parameters, indicating that the former can be used to predict the latter. Lumpfish eggs were mostly composed of triacylglycerides (TAGs) with some phosphatidylethanolamines (PEs) and phosphatidylcholines (PCs), and their lipid profiles were more sensitive to the different origins, mother weight/size and fertilization success than variables such as eggs size or larvae morphometric measures. PC and PE content of lumpfish eggs were positively correlated to both hatching success and fertilization rates, thus the lipidomic profiles, with some key highlighted lipid species were putative predictors of egg quality. Ova lipid profiling and egg quality in wild and captive lumpfish, Cyclopterus lumpus (Linnaeus, 1758)

I introduce a general, Fisher-style randomization testing framework to conduct nearly exact inference about the lack of effect of a binary treatment in the presence of very few, large clusters when the treatment effect is identified across clusters. The proposed randomization test formalizes and extends the intuitive notion of generating null distributions by assigning placebo treatments to untreated clusters. I show that under simple and easily verifiable conditions, the placebo test leads to asymptotically valid inference in a very large class of empirically relevant models. Examples discussed explicitly are (i) least squares regression with cluster-level treatment, (ii) difference-in-differences estimation, and (iii) binary choice models with cluster-level treatment. A simulation study and an empirical example are provided. The proposed inference procedure is easy to implement and performs well with as few as three treated and three untreated clusters., Comment: 37 pages, 3 figures, 1 table

We evaluated the potential of the marine bristleworm Hediste diversicolor (Polychaeta) to recycle side streams from aquaculture and biogas production. Polychaetes were fed along a gradient from pure aquaculture sludge (SS) to pure solid biogas digestate (SBD) in 33% steps, with a positive control reared on fish feed (FF). Worms fed with FF showed the highest specific growth rate; there were no significant differences in growth rates among worms fed pure SS, pure SBD or their mixtures. While the diets differed ignificantly in protein concentrations, the worms showed comparable protein concentrations at the end of the 30 d rearing period (42−47% of dry weight). Lipid content in the worms was positively correlated with that in their diets. The worms on mixtures of SS and SBD with different ratios showed similar amino acid profiles. Fatty acid (FA) composition in the polychaetes reflected diet, where increased fractions of SBD resulted in an increase in long-chain polyunsaturated FAs, such as arachidonic (C20:4 n-6) and eicosapentaenoic (C20:5 n-3) acids, whereas increased ratios of SS increased docosapentaenoic (C22:5 n-3) and docosahexaenoic (C22:6 n-3) acids. These results suggest that polychaetes can recycle organic nutrients from aquaculture and biogas side streams into high-quality proteins and lipids, and can potentially serve as ingredients for aquafeeds. © The authors 2019. Open Access under Creative Commons by Attribution Licence. Use, distribution and reproduction are un - restricted. Authors and original publication must be credited

The use of cleaner fish is an environmentally-friendly approach to combat the salmon louse, threatening commercial salmon farming. Dynamic Energy Budget (DEB) modelling helps understand the bioenergetics of early life stages of the cleaner fish, and can thereby aid optimisation of their culturing. Here, we report on our attempts to parametrise DEBkiss models for the yolk-feeding stages of two cleaner fish species, ballan wrasse (Labrus bergylta) and lumpfish (Cyclopterus lumpus). A range of measurements was taken over early development, including biometry (using imaging), weight and composition, as well as measurements of respiration rate. Despite the previous success of applying the DEBkiss model to early life stages of Atlantic cod, the model failed to capture the patterns of yolk depletion for ballan wrasse. The main issues were related to substantial changes in the water content of both yolk and structure over development, and a stop of growth before disappearance of the yolk sac. These issues require further experimental work to address, especially more efficient proxies for the dry mass of yolk and structure, such that these compartments can be efficiently separated. Nevertheless, apart from the pattern of yolk depletion, the model provides a reasonable explanation of all traits simultaneously. This indicates that model modifications may only need to be minor. For lumpfish, the data set was quite limited for testing of the DEBkiss model, due to the opacity of the egg and the fact that there was only one time point with measurements post hatch. Nevertheless, the data are consistent with the model. The modelling results indicate that both cleaner-fish species may have very similar bioenergetic parameters (and quite similar to Atlantic cod as well); the conspicuous difference in early life history may be mainly caused by the larger yolk provisioning in the egg, and late hatching, in lumpfish. The DEBkiss model is a simple and promising tool for bioenergetics of fish early-life stages. However, its application and in-depth testing is currently limited by the difficulties of obtaining detailed measurements on these life stages.

The ectoparasitic salmon louse (Lepeophtheirus salmonis, Kroyer 1836) remains a major disease problem and cost driver in commercial Atlantic salmon (Salmo salar L) farming and is also implicated in the decline of wild salmon stocks. The parasite feeds on mucus and blood causing skin damage on its host (i.e. leads to reduced welfare and disease resistance). Underwater lights (UL) are being used regularly in open-cage salmon aquaculture to delay maturation and increase feeding rates during the dark season. The aim of this study has therefore been to supply basic experimental data on the responses of the infectious copepodid stage of L. salmonis to discrete underwater light sources with different light qualities and intensities. The collective movement of a copepodid population in response to light sources was tested in a laboratory-based machine vision system using automated image processing. Copepodids always moved towards the light source even at low light intensities (1.5 × 10−3 μmol m−2 s−1) within a broad spectrum of visible light as well as near-UV. It is therefore plausible that subsea light sources frequently used in salmon farming under certain conditions can attract salmon lice copepodids and increase infection pressure. Moreover, the findings of our study support that light traps may be used to catch planktonic salmon lice. The actual effect of underwater light sources on the local distribution of salmon lice should be tested by controlled plankton sampling or monitoring in the vicinity of light sources compared to the surrounding water.

Three different experiments were conducted to examine the oocyte development of the polychaete Hediste diversicolor in response to changing photoperiod and temperature at three different periods of oogenesis. In experiment I, worms collected during summer were reared under constant or decreasing photoperiod and temperatures to test the combined effects of the summer–autumn photoperiod and temperature transition on oogenesis. The result showed females collected during summer showed the highest oocyte growth when exposed to constant temperatures combined with decreasing photoperiod and decreasing temperature combined with constant photoperiod. In experiment II, worms collected in late autumn were under mimicked or shortened seasonal changes in photoperiod to evaluate the effect of accelerated change on oocyte growth. The result showed worms had 1.5 times faster oocyte growth rates when exposed to accelerated rate of change in photoperiod (2.5 times faster). In experiment III, worms collected in spring were exposed to different temperature regimes to examine the effect of raising temperature on the synchronization of oocyte growth and maturation. The results showed worms collected in spring showed increased temperatures will increase oocyte maturation synchronicity. It was concluded temperature and photoperiod transition can increase the oocyte development. Copyright © 2020 Wang, Hagemann, Malzahn, Handå, Uhre, Kjørsvik and Reitan. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

To achieve efficient and preventive measures against salmon lice (Lepeophtheirus salmonis Krøyer, 1838) infestation, a better understanding of behavioral patterns of the planktonic life stages is key. To investigate light responses in L. salmonis copepodites, a non-intrusive experimental system was designed to measure behavioral responses in a 12.5-l volume using machine vision technology and methodology. The experimental system successfully tracked the collective movement patterns of the sea lice population during exposure to different light stimuli emitted from alternating zones in the system. This system could further be used to study behavioral responses to different physical cues of various developmental stages of sea lice or other zooplankton., Summary: A suggested method for tracking large populations (n=200) of small (

Despite the possible increase in use of anionic polyacrylamide (APAM) in enhanced oil recovery operations, very little relevant information regarding ecotoxicity exists. The current study assessed acute and sub-lethal toxicity in sensitive early life stages (ELS) of Atlantic cod (Gadus morhua) exposed to 200 kDa APAM under controlled laboratory conditions. Two experiments (screening and long-term study) were conducted covering ecologically relevant endpoints (survival, hatching, growth, deformations, respiration and heart rate) in fish developing through embryogenesis, hatching, yolk-sac larvae stage and the first feeding period. The screening experiment was an 8-day exposure of embryos, whereas in the long-term experiments embryos and developing larvae were exposed continuously for 23 days. In the screening experiment, a significant reduction in embryonic heart rate was observed during exposure to 150 and 1500 mg APAM/L. However, we observed no effects on fitness-related endpoints (survival, hatching and growth) at concentrations up to 1500 mg L−1 APAM. Also, for the long-term exposure from late embryo to first feeding larvae stage, we observed reduced heart rate at 125 mg L−1. No consistent responses on survival, growth or respiration were observed except for the highest concentration tested (6000 mg L−1). Dispersion modelling based on expected and relevant discharged polymer concentrations and durations showed that predicted environmental concentrations were orders of magnitude lower than the concentrations tested in our experiments, indicating that 200 kDa APAM will have a limited probability of causing fitness-related effects on Atlantic cod ELS.

Motivated by the need for additional tools to disinfect discharge water from well boats, and to prevent distribution of salmon lice, the effect of ultrasonic cavitation on the planktonic stages of the salmon louse, nauplii and copepodids, as well as marine heterotrophic bacteria, and the marine green microalgae Tetraselmis suecica, has been investigated. Survival and morphology were registered after different exposure times. Efficacy of the ultrasonic cavitation treatments varied with exposure time. A reduction in survival was registered even for the shortest exposure time (5 seconds) for both naupliar and copepodid stages of the salmon louse (36.7 ± 11.5 and 67.20 ± 7.2% survival respectively). Survival reached zero after exposure times of 20 and 60 seconds for the nauplii and copepodid stages, respectively. A reduction in 70% was observed for bacteria at all exposure times (5 to 300 s), while a reduction of 95% was observed after 300 s for algal cells. The logged energy transfer to the samples was on average 17.5 J/s. In conclusion, cavitation treatment is destructive for the planktonic stages of salmon lice, and may contribute to reduce discharge of pathogens and parasites from well boats when adapted for this purpose and combined with existing water disinfection methods. Norges Forskningsråd

The objective of the current study was to determine the extent to which planktonic sea lice (Lepeophtheirus salmonis Krøyer, 1838 and Caligus elongatus Nordmann, 1832) were present in the biofouling on open-sea net pens used for commercial rearing of Atlantic salmon (Salmo salar L.), and to assess if biofouling organisms on nets act as barriers similar to salmon lice skirts. We have examined two possible interactions of biofouling and planktonic sea lice, the first was if biofouling could function as a microhabitat for planktonic sea lice, with resuspension of sea lice during net cleaning operations. The second interaction was if biofouling may cause a retaining effect on the transport of planktonic stages out of the net pen. These interactions were investigated at different commercial salmon farms. With only one sea louse found among the biofouling on nets and cleaner fish shelters, we found no indication that sea lice utilized biofouling as a reservoir. This was further supported by the lack of impact on the proportion of samples with sea lice and the average density of sea lice in the water following the release of biofouling material during in situ net cleaning. Furthermore, the presence of biofouling had no effect on the proportion of samples with sea lice or the average density of planktonic sea lice in the net pens. The presence of a lice skirt resulted, however, in a significantly higher proportion of samples with planktonic sea lice inside the net pen in one of the two sites utilizing lice skirts. The results of our study suggested that the presence of biofouling has no influence on the average density and proportion of samples with planktonic stages of sea lice and that planktonic sea lice do not inhabit biofouling. Copyright © 2020 Jevne, Øvrelid, Hagemann, Bloecher, Steinhovden, Båtnes, Olsen and Reitan. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms

Knowledge of broodstock manipulation, gametogenesis, artificial fertilization and larval nutrition is a prerequisite to reach a large‐scale production of the polychaete Hediste diversicolor. In this study, the characteristics of oogenesis and spermatogenesis and embryonic and larval development were observed. Moreover, the effect of temperature on embryonic development and effect of diets and sediment on earlier juvenile development were tested. Mature oocytes were characterized by a spherical shape with a diameter of about 200 μm. They showed radial symmetry with a large centric nucleus surrounded by four distinctive layers. Embryo cleavage started between 4 and 10 hr after fertilization, and developed to the swimming trochophore stage after 5–6 days after fertilization at 11°C. The rate of embryonic development increased with a temperature increase from 6.1 to 21.2°C. The trochophore larvae increased in length from day 9 and commenced differentiation into 3‐setiger stage larvae at day 12. The length growth of larvae until 7‐setiger stage was 0.43 mm/day when fed with fish feed, while those fed shellfish diet and smolt sludge both grew around 0.21–0.23 mm/day. The results suggest that fish feed is a superior diet compared to shellfish diets and smolt sludge for the early larval stage of H. diversicolor. © 2020 The Authors. Aquaculture Research published by John Wiley & Sons Ltd This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

We exploit exogenous variation in years of completed college induced by draft-avoidance behavior during the Vietnam War to examine the impact of college on adult mortality. Our estimates imply that increasing college attainment from the level of the state at the 25th percentile of the education distribution to that of the state at the 75th percentile would decrease cumulative mortality for cohorts in our sample by 8 to 10 percent relative to the mean. Most of the reduction in mortality is from deaths due to cancer and heart disease. We also explore potential mechanisms, including differential earnings and health insurance.

Mass production of copepod eggs in intensive systems has recently been demonstrated to be economically feasible; a few companies producing copepod eggs have been established. It is well documented that water physiochemical variables could significantly influence the hatching success of Acartia tonsa Dana, 1849 (Copepoda: Calanoida) eggs. This information is important to end users in order to achieve a predictable output of nauplii when hatching eggs for live feed production in marine larviculture. The effect of different wavelengths and intensities of light on the 48-h egg hatching success (HS) of fresh and cold-stored (2 °C) A. tonsa eggs were examined in the present study. No correlations were observed between HS and light environment for fresh or cold eggs when they were hatched at wavelengths between 400 and 630 nm and at light intensities of 0.0016, 1, 5 and 16 µE m−2 s−1. Fresh eggs displayed the highest HS and declined with the time of storage. However, eggs being of same age showed a similar HS regardless of the light intensity and wavelength, including when hatched in darkness. We suggest that A. tonsa eggs produced in intensive cultures can be hatched without any concern to the light environment.

Increased aquaculture production will result in increased amounts of waste produced, and these wastes are highly underexploited. Polychaetes might effectively consume such waste and transfer them into compounds as marine proteins and lipids. In our study, growth and nutritional composition of the polychaete worm Hediste diversicolor (O.F. Müller, 1776) were analyzed to evaluate i) the capability of H. diversicolor to utilize waste from land-based salmon smolt farms for growth and ii) the nutritional composition of H. diversicolor cultivated on salmon smolt waste. The worms were fed iso‑carbonic diets comprised of fish feed, smolt waste, microalgae paste, and a 1:5 mixture (based on carbon content) of microalgae paste and smolt waste for a period of 30 days. H. diversicolor reared on fish feed grew significantly faster (wet weight basis) than worms grown on the other diets (SGR = 0.025 d−1). Worms fed with the mixture of smolt waste and microalgae showed the lowest growth (SGR = 0.003 d−1), while no significant differences were found between worms cultivated on smolt waste and microalgae paste (0.012 d−1vs. 0.014 d−1, respectively). The lipid content in H. diversicolor ranged between 12 and 16% of DW for all treatments, whereof approximately 45% of the total fatty acids were comprised of polyunsaturated fatty acids (PUFA). Palmitic acid (C16:0) and eicosapentaenoic acid (C20:5 n-3; EPA) were found to be the most abundant fatty acids in the worms. Docosahexaenoic acid (C20:6 n-3; DHA) content increased significantly from 1.5% to 4.6–7.8% of the total fatty acids during the experiment for all treatments. The protein content ranged between 54 and 58% of DW, and the most abundant essential amino acids (EAA) were found to be lysine and leucine. We calculated that potential polychaete biomass produced via recycling smolt waste nutrients will account for 8% of smolt production, indicating that H. diversicolor can not only be successfully reared on waste sludge from land-based salmon smolt aquaculture, but they also contain high valuable compounds, and therefore can help to increase the protein and lipid availability meanwhile decreasing the environmental impact from aquaculture activities. © 2018 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/BY-NC-ND/4.0/).

Machine vision represents an accurate and easily verifiable method for observing live organisms and this technology is constantly evolving in terms of accessibility and cost. Motivated by the complexity of observing small-sized aquatic organisms in experimental systems, and the difficulties related to real-time observation, sampling and counting without interfering with the organisms, we here present a new method for observing behaviour and dispersion of non-sessile zooplankton organisms using a custom-made tank with an associated machine vision system. The system was used in an experiment where the aim was to assess the effect of sound and ultrasound on the phototactic behaviour of copepodite stages of the salmon louse (

The aim of this study was to compare the nutritional composition and effects of short periods with cultivated copepod nauplii versus rotifers in first-feeding. Atlantic cod (Gadus morhua) and ballan wrasse (Labrus bergylta) larvae were given four different dietary regimes in the earliest start-feeding period. One group was fed the copepod Acartia tonsa nauplii (Cop), a second fed enriched rotifers (RotMG), a third fed unenriched rotifers (RotChl) and a fourth copepods for the seven first days of feeding and enriched rotifers the rest of the period (Cop7). Cod larvae were fed Artemia sp. between 20 and 40 dph (days posthatching), and ballan wrasse between 36 and 40 dph, with weaning to a formulated diet thereafter. In addition to assessing growth and survival, response to handling stress was measured. This study showed that even short periods of feeding with cultivated copepod nauplii (7 days) had positive long-term effects on the growth and viability of the fish larvae. At the end of both studies (60 days posthatching), fish larvae fed copepods showed higher survival, better growth and viability than larvae fed rotifers. This underlines the importance of early larval nutrition.

The effects of light and short-term temperature elevation on the 48-h egg hatching success (HS) of cold-stored (2 °C) Acartia tonsa Dana (Copepoda: Calanoida) eggs were examined in the present study. The eggs can be stored for up to 7.5 months and maintain their high hatching rate under optimal conditions. Intensively produced eggs from the copepod A. tonsa may be hatched and used as an inoculum for producing copepod nauplii as live feed for fish larvae. The HS for eggs that were directly exposed to LED light declined rapidly after 1 month of storage (from 91 to 25 %), and these eggs did not hatch at all after 3 months of storage. The highest HS found was for eggs stored in complete darkness. The HS for eggs stored in normoxic (≥7 mg DO L−1) and anoxic (≤0.03 mg DO L−1) seawater was not affected by short-term temperature transitions from 2 °C up to 9 or 17 °C for a period of 12 or 24 h, when hatched 1 week post-exposure. The global mean HS for eggs stored in normoxic seawater was 85.9 % and significantly lower compared to eggs stored under anoxic conditions after 3 weeks of storage (91.8 %) (P = 0.001; SNK).

Mass cultivation of marine copepods as live feed requires predictable and uniform production of a standard product for the end users, the hatcheries. A previously undescribed large egg type, measuring a mean diameter of 106.5 mu m, was characterized and compared to normal eggs (82.3 mu m) from a continuous culture of Acartia tonsa. The large egg type was significantly larger than the normal eggs, and only 1 large out of approximately 100 000 normal-sized eggs was found. Mean egg densities was 1.34 +/- 0.16 g/cm(3) and 1.20 +/- 0.07 g/cm(3) for normal and large eggs, respectively. The hypothesis that large eggs were dormant, as indicated from the relatively low hatching success of 60%, within 48 h, was rejected as no significant difference was found in egg volume-specific respiration rates or histological analysis of the chorion between the two egg types. The nauplii hatched from large eggs were correspondingly large, and the copepods remained large when developing into adulthood. The fact that copepods hatched from large eggs were fertile indicates no chromosomal abnormalities and suggests that this egg type represents the upper tail end of eggs in a classical normal distribution of size vs. frequency. The next generations' eggs were not as large as the ones they originated from suggesting that the rare large eggs represent a maternal effect. The large size eggs do however pose an interesting selection potential for designing large species-specific live feed products in aquaculture. (C) 2014 Elsevier B.V. All rights reserved.

In this paper I provide simple and easily verifiable conditions under which a strong form of stochastic equicontinuity holds in a wide variety of modern time series models. In contrast to most results currently available in the literature, my methods avoid mixing conditions. I discuss several applications in detail.

In this paper, I introduce a simple test for the presence of the data-generating process among several non-nested alternatives. The test is an extension of the classical J test for non-nested regression models. I also provide a bootstrap version of the test that avoids possible size distortions inherited from the J test.

We exploit exogenous variation in college completion induced by draft-avoidance behavior during the Vietnam War to examine the impact of college completion on adult mortality. Our preferred estimates imply that increasing college completion rates from the level of the state with the lowest induced rate to the highest would decrease cumulative mortality by 28 percent relative to the mean. Most of the reduction in mortality is from deaths due to cancer and heart disease. We also explore potential mechanisms, including differential earnings, health insurance, and health behaviors, using data from the Census, ACS, and NHIS.

We exploit exogenous variation in college completion induced by draft-avoidance behavior during the Vietnam War to examine the impact of college completion on adult mortality. Our preferred estimates imply that increasing college completion rates from the level of the state with the lowest induced rate to the highest would decrease cumulative mortality by 28 percent relative to the mean. Most of the reduction in mortality is from deaths due to cancer and heart disease. We also explore potential mechanisms, including differential earnings, health insurance, and health behaviors, using data from the Census, ACS, and NHIS.

In this paper I introduce quantile spectral densities that summarize the cyclical behavior of time series across their whole distribution by analyzing periodicities in quantile crossings. This approach can capture systematic changes in the impact of cycles on the distribution of a time series and allows robust spectral estimation and inference in situations where the dependence structure is not accurately captured by the auto-covariance function. I study the statistical properties of quantile spectral estimators in a large class of nonlinear time series models and discuss inference both at fixed and across all frequencies. Monte Carlo experiments illustrate the advantages of quantile spectral analysis over classical methods when standard assumptions are violated., Comment: 50 pages

OBJECTIVE The impact of injection flow rates, mono- or biphasic injection mode, and scan delay on liver and portal vein enhancement with helical CT was evaluated. MATERIALS AND METHODS The liver of 75 consecutive patients was examined with helical CT before and after injection of 100 ml iopromide (30 g of iodine). Patients were randomly assigned to three protocols: (1) injection flow: 2 ml/s; (2) injection flow; 4 ml/s (60 ml) + 2 ml/s (40 ml); and (3) injection flow: 4 ml/s. Scanning started 40 s after the beginning of contrast material injection. A second scan was performed 70 s after contrast agent injection in Protocol 1. RESULTS Mean parenchymal contrast enhancement was highest with Protocol 3 (48.5 HU) followed by Protocols 2 (38.9 HU) and 1 (early: 21 HU; late: 30.7 HU), with all differences being significant (p < 0.01). Enhancement of the portal vein was significantly higher with Protocols 3 and 2 (121 and 118 HU) than with Protocol 1 (early: 64 HU; late: 75 HU). CONCLUSION Good enhancement of the liver parenchyma and the portal vessels can be obtained with 30 g of iodine if a monophasic injection with a flow rate of 4 ml/s is used.