Egg distribution, bottom topography and small-scale cod population structure in a coastal marine system

Coastal marine species with pelagic egg and larval stages, such as the Atlantic cod Gadus morhua, can be structured into genetically distinct local populations on a surprisingly small geographic scale considering their dispersal potential. Mechanisms responsible for such small-scale genetic structure may involve homing of adults to their natal spawning grounds, but also local retention of pelagic eggs and larvae. For example, spawning within sheltered fjord habitats is expected to favour local retention of early life stages. Here, we studied the distribution of cod eggs along inshore-offshore transects in 20 Norwegian fjords. The general pattern exhibited across all fjords was a higher concentration of cod eggs inside the fjords than further offshore. In particular, fjords with shallow sills (model threshold 37 m) show an abrupt reduction in egg density over the sill. This study provides empirical support for an offspring retention hypothesis, which may help to explain the maintenance of local population structure in pelagic marine systems

A Cohort Study on Meniscal Lesions among Airport Baggage Handlers

Meniscal lesions are common and may contribute to the development of knee arthrosis. A few case-control and cross-sectional studies have identified knee-straining work as risk factors for meniscal lesions, but exposure-response relations and the role of specific exposures are uncertain, and previous results may be sensitive to reporting and selection bias. We examined the relation between meniscal lesions and cumulative exposure to heavy lifting in a prospective register-based study with complete follow-up and independent information on exposure and outcome. We established a cohort of unskilled men employed at Copenhagen Airport or in other companies in the metropolitan Copenhagen area from 1990 to 2012 (the Copenhagen Airport Cohort). The cohort at risk included 3,307 airport baggage handlers with heavy lifting and kneeling or squatting work tasks and 63,934 referents with a similar socioeconomic background and less knee-straining work. Baggage handlers lifted suitcases with an average weight of approximately 15 kg, in total approximately five tonnes during a 9-hour workday. The cohort was followed in the National Patient Register and Civil Registration System. The outcome was a first time hospital diagnosis or surgery of a meniscal lesion. Baggage handlers had a higher incidence of meniscal lesions than the referents. Within baggage handlers spline regression showed that the incidence rate ratio was 1.91 (95% confidence interval: 1.29-2.84) after five years as a baggage handler and then decreased slowly to reach unity after approximately 30 years, adjusted for effects of potential confounders. This relation between baggage handling and meniscal lesions was present for work on the apron which involves lifting in a kneeling or squatting position, but not in the baggage hall, which only involves lifting in standing positions. The results support that long-term heavy lifting in a kneeling or squatting position is a risk factor for the development of symptomatic meniscal lesions

Baggage handler seniority and musculoskeletal symptoms:is heavy lifting in awkward positions associated with the risk of pain?

OBJECTIVES: Heavy lifting is associated with musculoskeletal disorders but it is unclear whether it is related to acute reversible effects or to chronic effects from cumulated exposure. The aim of this study was to examine whether musculoskeletal symptoms in Danish airport baggage handlers were associated with their seniority as baggage handler, indicating chronic effects from cumulated workload. METHODS: We established a group of baggage handlers employed at Copenhagen Airport during the period 1983–2012 (n=3092) and a reference group of men in other unskilled occupations with less heavy work (n=2478). Data regarding work history, lifestyle and musculoskeletal symptoms were collected using a self-administered questionnaire (response rate 70.1% among baggage handlers and 68.8% among the reference group). RESULTS: The ORs of self-reported musculoskeletal symptoms during the last 12 months in the neck/upper back, lower back, shoulders, elbows, wrists, hips and knees were significantly higher in baggage handlers than in the reference group. These differences were explained by significant linear effects of baggage handler seniority for six anatomical regions. Adjustment for age, body mass index, smoking and leisure-time physical activity did not change these results. The findings were stable over age strata and among present and former baggage handlers. CONCLUSIONS: The risk of musculoskeletal symptoms in six anatomical regions increased with increasing seniority as a baggage handler. This is consistent with the assumption that cumulated heavy lifting may cause chronic or long-lasting musculoskeletal symptoms. However, we cannot exclude that other factors related to baggage handler seniority may explain some of the associations

Population dynamics and resting egg production in Daphnia: Interactive effects of mercury, population density and temperature

Toxicity studies on freshwater organisms are commonly conducted by quantifying effects on asexual (clonal) reproductive rates in Daphnia, whereas studies of effects on sexual reproductive rates remain relatively rare. Sexual reproduction in Daphnia and the associated production of resting eggs allows them to survive unfavorable environmental conditions and is thus a crucial component of their long-term fitness. It also maintains genetic diversity within Daphnia populations and hence their potential for adaptation to new environmental conditions. This aspect of their biology may therefore be important to consider in toxicity studies. The aim of this study was to investigate for the first time how mercury (Hg) affects sexual versus asexual reproduction in Daphnia under varying environmental conditions. Specifically, we experimentally tested the interactive effects of Hg and temperature on the population dynamics of Daphnia magna. For this purpose, we exposed D. magna to environmentally relevant concentrations (0 μg/L, 0.5 μg/L and 2 μg/L) of Hg (in the form of mercury (II) chloride) found in stream water and measured biomass growth rate resulting from asexual reproduction, and resting egg production resulting from sexual reproduction. This was done at both 17 °C and 24 °C. Biomass growth rate did not vary across Hg treatments and depended mainly on temperature and population density. Density dependence of biomass growth rate was indeed more pronounced at 24 °C than at 17 °C, as resource limitation from intraspecific competition was further exacerbated by the rise in feeding rates with temperature. Density dependence of resting egg production was unaffected by Hg and temperature, but resting egg production was higher under Hg exposure at low temperature. These findings show that depending on environmental conditions, rates of sexual reproduction in D. magna may respond to metal exposure at lower concentrations than those impacting population growth during the asexual phase

Metode for lokalisering og verdisetting av gyteplasser i fjorder med dype terskler, åpne havbukter og sund

Marine mapping of spawning areas for coastal cod have become increasingly important. Previous mapping have considered aggregations of mature cod. In this study we also evaluate distribution of cod eggs and their passive pelagic movement after spawning. This presents future methodology for mapping important areas in the spawning process. This study clearly shows the importance of incorporating egg distribution and water current

Pohjoismaiden keskuspankit tulevassa Euroopassa

EY-integraatio vaikuttaa merkittävästi Pohjoismaiden keskuspankki en toimintaan riippumatta siitä, minkälaisiin integraatioratkaisuihin lopulta päädytään. Muutospaineet johtuvat siitä, etteivät Pohjoismaat voi olla ottamatta huomioon lähialueidensa kehitystä. EY-maiden talouspoliittiset ratkaisut tulevat tulevaisuudessa hyvin pitkälle määräämään Pohjoismaiden talouspolitiikan lähtökohdat riippumatta institutionaalisista puitteista. Euroopan talous- ja rahaliiton (EMU) vuonna 1994 alkavan toisen vaiheen aikana EY-maiden ja EY:n jäseniksi pyrkivien maiden on käynnistettävä prosessi, joka tähtää kansallisten keskuspankki en täydelliseen riippumattomuuteen. Jo tässä vaiheessa vaaditaan julkisen sektorin keskuspankkirahoituksen kieltämistä. Myös pankkivaltuuston asemaa on tarkasteltava uudelta pohjalta ja keskuspankkien pääjohtajien nimittämiseen ja erottamiseen liittyviä säännöksiä on myös tarkistettava. Maastrichtin sopimuksen perusteella ei voida hahmottaa yksityiskohtaista kuvaa siitä, miten yhteistä rahapolitiikkaa harjoitetaan EMUn kolmannessa vaiheessa. Monet seikat viittaavat kuitenkin siihen, että kansalliset keskuspankit ovat mukana yhteisen raha- ja valuuttapolitiikan toteuttamisessa. EMUn toteutuminen vaikuttaa keskuspankki en rahoitus suhteisiin ja niiden taseiden rakenteeseen