44 research outputs found

    Pollutants Increase Song Complexity and the Volume of the Brain Area HVC in a Songbird

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    Environmental pollutants which alter endocrine function are now known to decrease vertebrate reproductive success. There is considerable evidence for endocrine disruption from aquatic ecosystems, but knowledge is lacking with regard to the interface between terrestrial and aquatic ecosystems. Here, we show for the first time that birds foraging on invertebrates contaminated with environmental pollutants, show marked changes in both brain and behaviour. We found that male European starlings (Sturnus vulgaris) exposed to environmentally relevant levels of synthetic and natural estrogen mimics developed longer and more complex songs compared to control males, a sexually selected trait important in attracting females for reproduction. Moreover, females preferred the song of males which had higher pollutant exposure, despite the fact that experimentally dosed males showed reduced immune function. We also show that the key brain area controlling male song complexity (HVC) is significantly enlarged in the contaminated birds. This is the first evidence that environmental pollutants not only affect, but paradoxically enhance a signal of male quality such as song. Our data suggest that female starlings would bias their choice towards exposed males, with possible consequences at the population level. As the starling is a migratory species, our results suggest that transglobal effects of pollutants on terrestrial vertebrate physiology and reproduction could occur in birds

    Food supplements increase adult tarsus length, but not growth rate, in an island population of house sparrows (Passer domesticus)

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    <p>Abstract</p> <p>Background</p> <p>Variation in food supply during early development can influence growth rate and body size in many species. However, whilst the detrimental effects of food restriction have often been studied in natural populations, how young individuals respond to an artificial increase in food supply is rarely investigated. Here, we investigated both the short-term and long-term effects of providing house sparrow chicks with food supplements during a key period of growth and development and assessed whether providing food supplements had any persistent effect upon adult size (measured here as tarsus length).</p> <p>Results</p> <p>Male nestlings tended to reach higher mass asymptotes than females. Furthermore, brood size was negatively associated with a chick's asymptotic mass. However, providing food supplements had no influence upon the growth rate or the asymptotic mass of chicks. Adults that received food supplements as chicks were larger, in terms of their tarsus length, than adults that did not receive extra food as chicks. In addition, the variation in tarsus length amongst adult males that were given food supplements as chicks was significantly less than the variance observed amongst males that did not receive food supplements.</p> <p>Conclusions</p> <p>Our results demonstrate that the food supply chicks experience during a critical developmental period can have a permanent effect upon their adult phenotype. Furthermore, providing extra food to chicks resulted in sex-biased variance in a size-related trait amongst adults, which shows that the degree of sexual size dimorphism can be affected by the environment experienced during growth.</p

    Circadian rhythm of photosynthetic oxygen evolution in Kappaphycus alvarezii (Rhodophyta): dependence on light quantity and quality

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    The rate of oxygen evolution of the tropical red alga Kappaphycus alvarezii was measured for 6 days in the laboratory using a computer-aided method for long-term recording. In cool white light Kappaphacus exhibited a robust circadian rhythm of O2 evolution in the irradiance range of 100 to 1000 µmol m-2 s-1. With increasing irradiance the period of the free-running rhythm, tau, decreased in blue and increased in red light, but did not change significantly in green light. The accelerating or slowing action of blue or red light, respectively, points to two photoreceptors used in the light transduction pathway of the circadian oscillator controlling oxygen evolution or the light reactions of photosynthesis in Kappaphycus. No significant changes of tau were observed with increasing irradiance in cool white light, possibly due to the additive, opposing responses caused by blue and red light

    Progesterone supplementation in natural cycles improves live birth rates after embryo transfer of frozen-thawed embryos-a randomized controlled trial

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    STUDY QUESTION Does supplementation with vaginal tablets of progesterone after frozen-thawed embryo transfer in natural cycles improve the live birth rate? SUMMARY ANSWER Supplementation with vaginal tablets of progesterone after frozen-thawed embryo transfer in natural cycles significantly improves the number of live births. WHAT IS KNOWN ALREADY Progesterone supplementation during luteal phase and early pregnancy may improve the number of live births after frozen-thawed embryo transfer. However, due to the limited number of previous studies, being mainly retrospective, evidence is still limited. STUDY DESIGN, SIZE, DURATION This is a prospective randomized controlled trial, performed at two university clinics. In total, 500 subjects were randomized with a 1:1 allocation into two groups, during the period February 2013 to March 2018. Randomization was performed after a frozen embryo transfer in a natural cycle by use of opaque sealed envelopes. The primary outcome was live birth rate; secondary outcomes were pregnancy, biochemical pregnancy, clinical pregnancy and miscarriage rate, and if there was a possible association between the serum progesterone concentration on the day of embryo transfer and live birth rate. PARTICIPANTS/MATERIALS, SETTING, METHODS Women, receiving embryo transfer in natural cycles participated in the study. The embryos were frozen on Day 2, 3, 5 or 6. In total, 672 women having regular menstrual cycles were invited to participate in the study; of those, 500 agreed to participate and 488 were finally included in the study. Half of the study subjects received progesterone supplementation with progesterone vaginal tablets, 100 mg twice daily, starting from the day of embryo transfer. The other half of the subjects were not given any treatment. Blood samples for serum progesterone measurements were collected from all subjects on the day of embryo transfer. MAIN RESULTS AND THE ROLE OF CHANCE There were no differences in background characteristics between the study groups. In the progesterone supplemented group, 83 of 243 patients (34.2%) had a live birth, compared to 59 of 245 patients (24.1%) in the control group (odds ratio 1.635, 95% CI 1.102-2.428, P = 0.017*). The number of pregnancies was 104 of 243 (42.8%) and 83 of 245 (33.9%), respectively (odds ratio 1.465, 95% CI 1.012-2.108, P = 0.049*) and the number of clinical pregnancies was 91 of 243 (37.4%) and 70 of 245 (28.6%), respectively (odds ratio 1.497, 95% CI 1.024-2.188, P = 0.043*). There were no significant differences in biochemical pregnancy rate or miscarriage rate. There was no correlation between outcome and serum progesterone concentration. LIMITATIONS, REASONS FOR CAUTION The study was not blinded because placebo tablets were not available. Supplementation started on embryo transfer day, regardless of the age of the embryos, which resulted in a shorter supplementation time for Day 5/6 embryos compared to Day 2/3 embryos. WIDER IMPLICATIONS OF THE FINDINGS Supplementation with progesterone in natural cycles improved the number of live births after frozen-thawed embryo transfer and should therefore be considered for introduction in clinical routine. STUDY FUNDING/COMPETING INTEREST(S) The study was funded by Uppsala University, the Uppsala-Family Planning Foundation, and Ferring Pharmaceuticals AB, Malmo, Sweden. The authors have no personal conflicting interests to declare. DATE OF FIRST PATIENT'S ENROLMENT 18 February 2013

    Voices on Relocation and Aging in Place in Very Old Age--A Complex and Ambivalent Matter.

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    PURPOSE: This cross-national qualitative study explores how very old people reflect upon relocation and aging in place. DESIGN AND METHODS: Swedish and German data are utilized in this study. About 80 community-living participants, 80-89 years of age, were interviewed with open-ended questions at home by trained interviewers. The interviews were analyzed by using conventional qualitative content analyses. RESULTS: Reasoning about relocation or aging in place in very old age is a complex and ambivalent matter. A variety of reflections, emotions, and behaviors for and against a move are revealed. Reasons to move reflect the urge to maintain independence, to stay in control, and to avoid loneliness. This is mainly expressed reactively. Reasons not to move reflect a strong attachment to the home and neighborhood. Moreover, reasons not to move reflect practical aspect such as economy and strain, as well as fear of losing continuity of habits and routines. IMPLICATIONS: There is a need for society to develop counseling systems to meet very old people's ambivalence and practical considerations to move or not to move. Thus, the ambivalence to stay put or to relocate needs to be further explored from an applied perspective by also taking nonmovers into account

    Exploring Associations of Housing, Relocation, and Active and Healthy Aging in Sweden : Protocol for a Prospective Longitudinal Mixed Methods Study

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    Background: While housing and neighborhood features have the potential to impact opportunities for active aging, there is a lack of knowledge related to how older people reason regarding their housing situation and how housing and fulfillment of relocation are associated with active and healthy aging. Objective: The objectives of Prospective RELOC-AGE are to study housing choices and relocation and explore effects on active and healthy aging among men and women aged 55 years and older in Sweden considering relocation. Methods: The estimated sample (2800) will include people aged 55 years and older being listed for relocation at either of two housing companies: a local public housing company in Southern Sweden and a national condominium provider. Prospective RELOC-AGE has a 2-level longitudinal mixed methods design and includes quantitative surveys (implemented by a professional survey company) and a telephone interview for baseline data collection in 2021, with follow-ups with the same procedures in 2022 and 2023. The survey and interviews include questions related to present housing and neighborhood, relocation plans and expectations, a range of perspectives on active and healthy aging, and demographics. Linking to national registers will provide additional data on home help and health care use, objective housing, and neighborhood characteristics. To explore what housing attributes older adults considering relocation find important and to what extent when making their decisions on housing, we will develop a discrete choice experiment to be implemented with a subsample of participants. Further, a grounded theory approach will be applied to collect in-depth interview data from participants who have moved to another dwelling, within 6 months of the move. A follow-up interview 12 months later will focus on participants’ deepened experience over time in terms of fulfilled expectations and relocation experiences. Results: As of submission of this protocol (June 2021), recruitment has commenced with approximately 960 respondents to the survey and ongoing telephone interviews. We anticipate recruitment and data collection based on surveys and interviews to continue during 2021. Conclusions: Prospective RELOC-AGE has the capacity to generate new policy-relevant knowledge on associations of housing, relocation, and active and healthy aging. Such knowledge is relevant for the development of proactive approaches to housing in old age on the individual, group, and societal levels.peerReviewe

    Growth kinetics related to physiological parameters in young Saccorhiza dermatodea and Alaria esculenta sporophytes exposed to UV radiation

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    Young sporophytes of Saccorhiza dermatodea and Alaria esculenta cultured from Spitsbergen isolates were exposed in the laboratory to either only photosynthetically active radiation (PAR) or to a spectrum including UV-radiation (PAR+UVA+UVB) by use of cutoff glass filters. The plants were grown at 8±2°C and 16:8 h light-dark cycles with 6 h additional UV exposure in the middle of the light period. Growth was measured every 10 min using growth chambers with online video measuring technique for 18-21 days. Tissue morphology and absorption spectra were measured in untreated young sporophytes while tissue chlorophyll-a content and DNA damage were measured from treated thalli at the end of the experiment. Under UVR, growth rates of S. dermatodea were significantly reduced while A. esculenta have a potential to acclimate. Tissue chlorophyll-a contents in both species were not significantly different between treatments suggesting that these algae may acclimate to moderate UVR fluence. Higher DNA damage in S. dermatodea effectively diverted photosynthetic products for repair constraining growth. Tissue optics (opacity and translucence) was correlated to the tissue absorbance in the UVR region characteristics of phlorotannin, an important UV-absorbing compound in brown macroalgae. Growth rates of sporophytes of both species exposed to PAR without UV was similar during day and night. The results showed that both species can recruit and inhabit a similar coastal zone when appropriate strategies are expressed to minimize damage in response to the stress factor. © Springer-Verlag 2005
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