83 research outputs found

    Genetic differentiation in an endangered and strongly philopatric, migrant shorebird

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    Populations living in fragmented habitats may suffer from loss of genetic variation and reduced between-patch dispersal, which are processes that can result in genetic differentiation. This occurs frequently in species with reduced mobility, whereas genetic differentiation is less common among mobile species such as migratory birds. The high dispersal capacity in the latter species usually allows for gene flow even in fragmented landscapes. However, strongly philopatric behaviour can reinforce relative isolation and the degree of genetic differentiation. The Southern Dunlin (Calidris alpina schinzii) is a philopatric, long-distance migratory shorebird and shows reduced dispersal between isolated breeding patches. The endangered population of the Southern Dunlin breeding at the Baltic Sea has suffered from habitat deterioration and fragmentation of coastal meadows. We sampled DNA across the entire population and used 12 polymorphic microsatellite loci to examine whether the environmental changes have resulted in genetic structuring and loss of variation. </p

    Maternally transferred thyroid hormones and life-history variation in birds

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    1. In vertebrates, thyroid hormones (THs) play an important role in the regulation of growth, development, metabolism, photoperiodic responses and migration. Maternally transferred THs are important for normal early phase embryonic development when embryos are not able to produce endogenous THs. Previous studies have shown that variation in maternal THs within the physiological range can influence offspring phenotype. 2. Given the essential functions of maternal THs in development and metabolism, THs may be a mediator of life-history variation across species. 3. We tested the hypothesis that differences in life histories are associated with differences in maternal TH transfer across species. Using birds as a model, we specifically tested whether maternally transferred yolk THs covary with migratory status, developmental mode and traits related to pace-of-life (e.g. basal metabolic rate, maximum life span). 4. We collected un-incubated eggs (n = 1-21 eggs per species, median = 7) from 34 wild and captive bird species across 17 families and six orders to measure yolk THs [both triiodothyronine (T3) and thyroxine (T4)], compiled life-history trait data from the literature and used Bayesian phylogenetic mixed models to test our hypotheses. 5. Our models indicated that both concentrations and total amounts of the two main forms of THs (T3 and T4) were higher in the eggs of migratory species compared to resident species, and total amounts were higher in the eggs of precocial species, which have longer prenatal developmental periods, than in those of altricial species. However, maternal yolk THs did not show clear associations with pace-of-life-related traits, such as fecundity, basal metabolic rate or maximum life span. 6. We quantified interspecific variation in maternal yolk THs in birds, and our findings suggest higher maternal TH transfer is associated with the precocial mode of development and migratory status. Whether maternal THs represent a part of the mechanism underlying the evolution of precocial development and migration or a consequence of such life histories is currently unclear. We therefore encourage further studies to explore the physiological mechanisms and evolutionary processes underlying these patterns.</p

    Unexpected diversity in socially synchronized rhythms of shorebirds

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    The behavioural rhythms of organisms are thought to be under strong selection, influenced by the rhythmicity of the environment. Such behavioural rhythms are well studied in isolated individuals under laboratory conditions, but free-living individuals have to temporally synchronize their activities with those of others, including potential mates, competitors, prey and predators. Individuals can temporally segregate their daily activities (for example, prey avoiding predators, subordinates avoiding dominants) or synchronize their activities (for example, group foraging, communal defence, pairs reproducing or caring for offspring). The behavioural rhythms that emerge from such social synchronization and the underlying evolutionary and ecological drivers that shape them remain poorly understood. Here we investigate these rhythms in the context of biparental care, a particularly sensitive phase of social synchronization where pair members potentially compromise their individual rhythms. Using data from 729 nests of 91 populations of 32 biparentally incubating shorebird species, where parents synchronize to achieve continuous coverage of developing eggs, we report remarkable within-and between-species diversity in incubation rhythms. Between species, the median length of one parent's incubation bout varied from 1-19 h, whereas period length-the time in which a parent's probability to incubate cycles once between its highest and lowest value-varied from 6-43 h. The length of incubation bouts was unrelated to variables reflecting energetic demands, but species relying on crypsis (the ability to avoid detection by other animals) had longer incubation bouts than those that are readily visible or who actively protect their nest against predators. Rhythms entrainable to the 24-h light-dark cycle were less prevalent at high latitudes and absent in 18 species. Our results indicate that even under similar environmental conditions and despite 24-h environmental cues, social synchronization can generate far more diverse behavioural rhythms than expected from studies of individuals in captivity. The risk of predation, not the risk of starvation, may be a key factor underlying the diversity in these rhythms.</p

    Unexpected diversity in socially synchronized rhythms of shorebirds

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    The behavioural rhythms of organisms are thought to be under strong selection, influenced by the rhythmicity of the environment1, 2, 3, 4. Such behavioural rhythms are well studied in isolated individuals under laboratory conditions1, 5, but free-living individuals have to temporally synchronize their activities with those of others, including potential mates, competitors, prey and predators6, 7, 8, 9, 10. Individuals can temporally segregate their daily activities (for example, prey avoiding predators, subordinates avoiding dominants) or synchronize their activities (for example, group foraging, communal defence, pairs reproducing or caring for offspring)6, 7, 8, 9, 11. The behavioural rhythms that emerge from such social synchronization and the underlying evolutionary and ecological drivers that shape them remain poorly understood5, 6, 7, 9. Here we investigate these rhythms in the context of biparental care, a particularly sensitive phase of social synchronization12 where pair members potentially compromise their individual rhythms. Using data from 729 nests of 91 populations of 32 biparentally incubating shorebird species, where parents synchronize to achieve continuous coverage of developing eggs, we report remarkable within- and between-species diversity in incubation rhythms. Between species, the median length of one parent’s incubation bout varied from 1–19 h, whereas period length—the time in which a parent’s probability to incubate cycles once between its highest and lowest value—varied from 6–43 h. The length of incubation bouts was unrelated to variables reflecting energetic demands, but species relying on crypsis (the ability to avoid detection by other animals) had longer incubation bouts than those that are readily visible or who actively protect their nest against predators. Rhythms entrainable to the 24-h light–dark cycle were less prevalent at high latitudes and absent in 18 species. Our results indicate that even under similar environmental conditions and despite 24-h environmental cues, social synchronization can generate far more diverse behavioural rhythms than expected from studies of individuals in captivity5, 6, 7, 9. The risk of predation, not the risk of starvation, may be a key factor underlying the diversity in these rhythms

    Salakavala selkäsärky

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    Thrombomodulin and catecholamines as post-mortem indicators of hypothermia

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    Abstract Hypothermia deaths pose a difficult challenge from the medico-legal point of view because no specific traces are left on the cadaver to be examined post-mortem. The concentrations of urinary catecholamines, adrenaline and noradrenaline increase in various stressful situations including cold stress, and high levels have been considered to be suggestive of lethal hypothermia. There is, however, a need for a better hypothermia indicator. A potential candidate could be thrombomodulin (TM), an endothelially expressed protein whose plasma concentration has been shown to elevate in response to hypothermia. TM and catecholamine levels were studied in short-term cold exposure (human subjects, n = 7), in mild and severe hypothermia with or without rewarming (rats, n = 96) and in hypothermia deaths compared with deaths from cardiovascular diseases, traumas and other causes (autopsy cases, total n = 552). Myocardial thrombomodulin transcript expression was increased in severely hypothermic rats, but was lower in hypothermia deaths than in other causes. The circulating TM level was transiently reduced in severe hypothermia. The myocardial and urinary TM protein levels were reduced in lethal hypothermia compared with other causes of death. TM and catecholamine levels correlated significantly in blood and urine both in living subjects and post-mortem examination. In severely hypothermic rats, there was an inverse relationship between plasma adrenaline concentration and myocardial thrombomodulin transcript level. The results suggest that TM expression and secretion are altered by hypothermia, possibly linked to the actions of catecholamines. Analysing the post-mortem catecholamine and TM levels provides evidence of ante-mortem cold stress in suspected hypothermia deaths. Further studies should be conducted in order to reveal the exact mechanisms behind the regulation of TM on cell level.Tiivistelmä Paleltumiskuolemat ovat oikeuslääketieteellisesti haastavia, koska vainajaan ei jää paleltumiseen viittaavia yksiselitteisiä löydöksiä. Virtsan katekoliamiinien, adrenaliinin ja noradrenaliinin, pitoisuudet kasvavat stressitilanteissa kuten kylmäaltistuksessa. Korkeita pitoisuuksia on pidetty paleltumiseen viittaavana tekijänä. Paremmalle paleltumista osoittavalle merkkiaineelle on kuitenkin selkeä tarve. Eräs mahdollinen merkkiaine voisi olla trombomoduliini (TM), joka on endoteelisolujen tuottama proteiini. Sen plasmapitoisuuden on aiemmin osoitettu nousevan alilämpöisyystilassa. TM- ja katekoliamiinitasoja tutkittiin lyhyessä kylmäaltistuksessa (koehenkilöt, n = 7) sekä lievässä ja vaikeassa alilämpöisyystilassa joko lämmityksen jälkeen tai ilman lämmitystä (rotat, n = 96). Lisäksi verrattiin paleltumisen, sydän- ja verisuonitautien, vammojen sekä muiden syiden aiheuttamia kuolemia (ruumiinavausaineisto, n = 552). Sydänlihaksen trombomoduliini-transkriptin taso oli kohonnut vaikeasti alilämpöisillä rotilla, mutta se oli matalampi paleltumiskuolemissa kuin muissa kuolemissa. Veren TM-taso oli hetkellisesti alentunut vaikeassa alilämpöisyystilassa. Sydänlihaksen ja virtsan TM-proteiinipitoisuudet olivat matalampia paleltumiskuolemissa kuin muissa kuolemansyissä. TM- ja katekoliamiinitasot korreloivat merkittävästi veressä ja virtsassa sekä koehenkilöillä ja -eläimillä että vainaja-aineistossa. Vaikeasti alilämpöisillä rotilla todettiin käänteinen suhde plasman adrenaliinipitoisuuden ja sydänlihaksen trombomoduliini-transkriptitason välillä. Tulosten perusteella alilämpöisyystila muuttaa TM:n ekspressiota ja erittymistä, mikä voi liittyä katekoliamiinien vaikutuksiin. Kuolemanjälkeisten TM- ja katekoliamiinitasojen määritys tuo lisänäyttöä kuolemaa edeltäneestä kylmävaikutuksesta epäiltäessä paleltumiskuolemaa. Lisätutkimuksia tarvitaan TM:n solutason säätelymekanismien selvittämiseksi

    A postcolonial deconstruction of diversity management and multiculturalism

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    Abstract Because issues of workplace diversity are strongly affected by historical power relations, this chapter adopts a postcolonial perspective to critically review the notion of multiculturalism that underlies the current paradigm of diversity. To search for alternative grounds for the theoretical development of diversity management, multiculturalism is investigated as an instrument of control deeply connected to broader institutionalized power structures. Drawing on key insights from postcolonialism, it is argued that embracing multiculturalism has resulted in diversity research that is inappropriate for addressing the complex realities of cultural encounters in which identities and otherness are constructed in contemporary organizations. The chapter demonstrates that by relying on multiculturalism, diversity becomes presented through simplistic and fixed categorizations of identity and culture that reinforce inequalities. Stressing the importance of considering culture from a new perspective, and an alternative approach for theorizing cultural diversity through the concept of the third space is introduced

    Hoidosta hautaan:lääketieteellisen hoidon aiheuttamat kuolemat ja niiden tutkinta

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    Tiivistelmä Hoitokuolemalla tarkoitetaan kuolemaa, johon johtanut tapahtumaketju on alkanut lääketieteellisestä hoidosta. Potilasturvallisuuden kannalta kuolema on vakavin haittatapahtuma. Hoitokuolemien määristä ei ole olemassa tarkkoja tilastotietoja, mihin vaikuttaa muun muassa määritelmien vaihtelevuus. Suomessa epäily hoitokuolemasta edellyttää oikeuslääketieteellistä kuolemansyynselvitystä, minkä lisäksi tutkinta jakaantuu eri viranomaisille valvonta-, oikeus- ja vahinkoprosesseihin. Oikeuslääketieteellisen ruumiinavausaineiston ja kuolintodistusten perusteella hoidon osuutta kuolemassa epäillään usein, mutta hoitokuolemaksi luokiteltuja tapauksia on suhteellisen vähän. Suurin osa niistä liittyy lääkehoitoon ja suuririskisiksi tiedettyihin toimenpiteisiin. Varsinaisten hoitovirheiden aiheuttamat kuolemat ovat todellisuudessa todennäköisesti aiempaa arvioitua harvinaisempia. Hoitokuolemaepäilyjen oikeuslääketieteellinen selvittäminen on tärkeää, jotta voidaan edistää potilasturvallisuutta sekä varmistaa vainajien, omaisten ja hoitohenkilökunnan oikeusturvan toteutuminen
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