An insight into the reproductive biology of the bearded goby Sufflogobius bibarbatus

Preliminary results obtained from histological analyses of the male reproductive organs, supplemented with field and behavioural data, indicate that Sufflogobius bibarbatus, a small, slow growing gobiid exhibiting low fecundity, which plays an important role in the food web off Namibia, where large areas of the shelf are hypoxic, spawns demersally. Large males defend benthic nests, possibly at the edge of the hypoxic shelf. Male reproductive strategy appears to be flexible, and tentative evidence to suggest that polygyny and sneaking may also occur is presented.Web of Scienc

Good parenting may not increase reproductive success under environmental extremes

For species exhibiting parental care, the way in which parents adjust care behaviour to compensate for environmental change potentially influences offspring survival and, ultimately, population viability. Using the three‐spined stickleback (Gasterosteus aculeatus) – a species in which males provide parental care by building and tending a nest and fanning the eggs – we examined how low dissolved oxygen (DO) levels affect paternal care, embryo development and survival. While levels of nest tending were unaffected by DO level, we found that larger males fanned their embryos more under low oxygen conditions. This resulted in faster rates of embryo development within the clutches of these larger males, but reduced embryo survival at 7d post‐fertilisation compared to clutches of smaller males. Our results suggest that although parents may attempt to compensate for environmental change via alterations to care behaviour, their ability to do so can be dependent on parental phenotype. This sets up the potential for oxygen levels to act on the strength and direction of selection within populations. We discuss possible explanations for the surprising result that supposedly adaptive changes in care behaviour by large males (i.e. increased fanning) led to reduced embryo survival at 7d post‐fertilisation, and whether, as a consequence, acute environmental conditions may have the potential to overwhelm selection on sexual traits

Paternal care, filial cannibalism and sexual conflict in the sand goby, Pomatoschistus minutus

Natural and sexual selection and sexual conflict are forces shaping the evolution of reproductive behaviour, while constrained by factors like environment, physiology and life-history trade-offs. Parental care is costly both in terms of time and energy. In fish, filial cannibalism is a strategy for caring males to compensate for some of the energy loss. Human impact like eutrophication also alters the basics for animals living in that environment. It is fundamental to any species to adjust its behaviour to a changing environment. Studying sand goby males, I found trade-offs both regarding parental care allocations, like ventilation vs. predator defence, and investment in present vs. future reproductive success. Paternal sand gobies exposed to water with low oxygen levels increased their fanning effort but did not compensate by eating more eggs, even though an increased current parental effort should affect future reproductive success negatively. Investigating if patterns of filial cannibalism change with time of season, I found no correlation. Theory predicts that it should pay more to eat eggs early, when future mating potential is higher than late in the season. However, as early hatching fry are likely to gain higher fitness through larger size the next breeding season, this may provide an opposing selection pressure. In species with male care the only way a female can affect the level of post-spawning care is by choosing a good mate. A female preference to spawn in nests that already contain eggs of other females has been interpreted as a means to avoid filial cannibalism through a dilution effect or to decrease the costs of search time. Yet, in my study females did not avoid filial cannibalism by preferring large clutches to small ones. Oxygenation of the eggs might be a key factor, since both large and small females preferred spawning in nests with small clutches. Thus, as in most animals, trade-offs clearly govern the reproductive behaviour of sand gobies

Ventilation or nest defense—parental care trade-offs in a fish with male care

Brood guarding animals face many critical trade-offs. Sand goby males (Pomatoschistus minutus) build nests with larger openings during low oxygen conditions, presumably to enhance ventilation. However, this may make the nest easier for egg predators to detect and harder for guarding males to defend. Manipulating oxygen level and predator presence (a small crab) for small and large males, we found support for a parental trade-off between fanning and nest defense. An increased fanning activity resulted in less time for guarding. Small males and males in low oxygen showed a higher fanning expenditure than large males and males in high oxygen, but surprisingly, filial cannibalism did not differ between these groups. Males built larger nest openings in low than high oxygen. However, males in both high and low oxygen treatments reduced their nest opening size in the presence of a predator, again indicating an important trade-off between ventilation and nest defens

Architecture Framework for Blockchain Implementation

Background: The release of Nakamoto’s whitepaper, describing the inner workings of Bitcoin, triggered a vast interest in blockchain’s core. In resent years, an elevated technological fascination is evident in the large number of new blockchain platforms, tokens and technological solutions aiming to solve the technology’s shortcomings. An enabler of high security, transparency, and auditability, blockchain has been envisioned as the missing piece of the foreseen IoT breakthrough. Industries outside cryptocurrencies are starting to show an elevated interest in the technology. Objective: To facilitate future blockchain implementations, an architecture framework is derived with appropriate viewpoints, models and corresponding guidelines that software architects are recommended to consider. Methods: The framework is empirically constructed following a design science research methodology over three cycles. Challenging scenarios and guidelines are gathered from a workshop with five case company participants, 14 interviews, and a structured literature review including 229 primary studies of which 17 are thoroughly perused. Two industry evaluation sessions with case company representatives assess the framework. An interviewee survey sent out to study participants and a SAPSA conference talk with subsequent feedback from impartial industry representatives further evaluate the work. Results: Beyond well known viewpoints traditionally used in architecture frameworks, five new viewpoints can be derived from the findings. The applicability viewpoint addresses the pronounced difficulty of finding an appropriate use case and using blockchain properly. The ecosystem viewpoint addresses the current scarcity of blockchain expertise and the means by which developers can be supported in their smart contract development. The infrastructure viewpoint highlights how the system’s topology and platform parameters affect its performance, scalability and transaction throughput. The legal viewpoint helps architects taking informed decisions in the light of current legal developments with an accent on network liability and private data management. Lastly, the end user viewpoint attend to the identified prioritization of technological aspects over customer value. Conclusions: The framework need further refinement, e.g. through the addition of extra viewpoints from other frameworks. Nevertheless, the ambition to establish initial implementation practices is satisfied. The viewpoints and their respective guidelines are anticipated to be of industrial value, based on evaluations provided by the case company and other industry representatives

Hand-Arm Vibrations’ Association with Myocardial Infarction

This study found no association between exposure to hand-arm vibrations (HAV) and myocardial infarction. Data was gathered from the Swedish National Cohort on Work and Health and consists of all individuals born in Sweden from 1930 to 1990, with demographic, occupational, and MI data available between 1968 and 2017. All workers in Sweden with an occupational code between 1985 and 2013 were matched to the job-exposure matrix on occupational exposures. The model was adjusted for demographic data and other occupational exposures. The hazard ratio with a 95% confidence interval was 1.01 (0.92–1.11) for those exposed above the daily equivalent HAV level of 5 m/s2

Emotional Distress as a Predictor of Statin Non-adherence among Swedish First-Time Myocardial Infarction Patients, 2006–2013

Background: Emotional distress (depression and anxiety) has been known to affect mortality after a myocardial infarction (MI). One possible mechanism is through medication non-adherence. Few studies have investigated the link between statin adherence and emotional distress, and results are not consistent. We aimed to explore whether emotional distress affects adherence among first-time MI patients younger than 75 years old receiving a prescription for the first time. Methods: We identified first-MI individuals younger than 75 years from the SWEDEHEART national quality registers discharged with a statin prescription. The main exposure was the anxiety/depression portion of the EQ-5D from Interview 1 (6-10 weeks post -MI) and Interview 2 (12-14 months post -MI). We calculated adherence from the Swedish Prescribed Drugs Register during three observation periods (OP): [1] Interview 1 to Interview 2, [2] one year post Interview 2, and [3] two years post Interview 1. Results: Emotional distress at Interview 1 was not associated with statin adherence for OP1 (RR: 0.99, 95% CI: 0.98, 1.01). Emotional distress at Interview 2 was associated with lower adherence one year later (RR: 0.95, 95% CI: 0.93, 0.98). Emotional distress at Interview 1 was associated with a small decrease in adherence in the complete OP for adherence (RR: 0.98, 95% CI: 0.96, 0.99). Conclusion: Emotional distress was marginally, but independently, associated with lower adherence to statin two years after the MI. Our study suggests that emotional distress may be an important factor for long-term statin adherence, and, thus, may play a clinically important role in long-term outcome