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| 5. |
- Lutzenkirchen, J., et al.
(författare)
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The surface chemistry of sapphire-c: A literature review and a study on various factors influencing its IEP
- 2018
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Ingår i: Advances in Colloid and Interface Science. - : Elsevier BV. - 0001-8686 .- 1873-3727. ; 251, s. 1-25
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Forskningsöversikt (refereegranskat)abstract
- A wide range of isoelectric points (IEPs) has been reported in the literature for sapphire-c (alpha-alumina), also referred to as basal plane, (001) or (0001), single crystals. Interestingly, the available data suggest that the variation of IEPs is comparable to the range of IEPs encountered for particles, although single crystals should be much better defined in terms of surface structure. One explanation for the range of IEPs might be the obvious danger of contaminating the small surface areas of single crystal samples while exposing them to comparatively large solution reservoirs. Literature suggests that factors like origin of the sample, sample treatment or the method of investigation all have an influence on the surfaces and it is difficult to clearly separate the respective, individual effects. In the present study, we investigate cause-effect relationships to better understand the individual effects. The reference IEP of our samples is between 4 and 4.5. High temperature treatment tends to decrease the IEP of sapphire-c as does UV treatment. Increasing the initial miscut (i.e. the divergence from the expected orientation of the crystal) tends to increase the IEP as does plasma cleaning, which can be understood assuming that the surfaces have become less hydrophobic due to the presence of more and/or larger steps with increasing miscut or due to amorphisation of the surface caused by plasma cleaning. Pre-treatment at very high pH caused an increase in the IEP. Surface treatments that led to IEPs different from the stable value of reference samples typically resulted in surfaces that were strongly affected by subsequent exposure to water. The streaming potential data appear to relax to the reference sample behavior after a period of time of water exposure. Combination of the zeta potential measurements with AFM investigations support the idea that atomically smooth surfaces exhibit lower IEPs, while rougher surfaces (roughness on the order of nanometers) result in higher IEPs compared to reference samples. Two supplementary investigations resulted in either surprising or ambiguous results. On very rough surfaces (roughness on the order of micrometers) the IEP lowered compared to the reference sample with nanometer-scale roughness and transient behavior of the rough surfaces was observed. Furthermore, differences in the IEP as obtained from streaming potential and static colloid adhesion measurements may suggest that hydrodynamics play a role in streaming potential experiments. We finally relate surface diffraction data from previous studies to possible interpretations of our electroldnetic data to corroborate the presence of a water film that can explain the low IEP. Calculations show that the surface diffraction data are in line with the presence of a water film, however, they do not allow to unambiguously resolve critical features of this film which might explain the observed surface chemical characteristics like the dangling OH-bond reported in sum frequency generation studies. A broad literature review on properties of related surfaces shows that the presence of such water films could in many cases affect the interfacial properties. Persistence or not of the water film can be crucial. The presence of the water film can in principle affect important processes like ice-nucleation, wetting behavior, electric charging, etc. (C) 2017 Elsevier B.V. All rights reserved.
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| 9. |
- Landin-Olsson, M., et al.
(författare)
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Islet cell and thyrogastric antibodies in 633 consecutive 15- to 34-yr-old patients in the diabetes incidence study in Sweden
- 1992
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 41:8, s. 1022-1027
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Tidskriftsartikel (refereegranskat)abstract
- The effect of age on ICA and thyrogastric antibodies at diagnosis of IDDM was evaluated in 633 consecutively diagnosed Swedish diabetic patients aged 15-34 yr and in 282 volunteers of the same age. ICAs were present in 61% (383 of 633) of the patients and in 2% (5 of 282) of control subjects. When the initial classification was considered, ICAs were detected in 69% (327 of 473) of patients with IDDM, 23% (19 of 83) of those with NIDDM, 50% (36 of 72) of those with unclassifiable diabetes, and 20% (1 of 5) of those with secondary diabetes. The frequency of ICA fell significantly (P < 0.001) with age in IDDM patients from 77% (104/135) in those 15-19 yr old to 52% (50 of 96) in 30- to 34-yr-old IDDM patients. The low frequency of ICA in 30- to 34-yr-old IDDM patients was confined to men (42%, 28 of 66). The frequency of gastric (H+, K+-ATPase) antibodies was significantly (P < 0.05) higher in IDDM patients (10%, 47 of 449) than in patients with NIDDM (3%, 3 of 80) and unclassifiable diabetes (4%, 3 of 72). In conclusion, the frequency of ICA at the diagnosis of IDDM in young adult subjects decreases with increasing age, particularly in men. The frequent finding of ICA in patients considered to have NIDDM or unclassifiable diabetes indicates that misclassification of diabetes is frequent in young adult patients recently diagnosed with diabetes.
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| 13. |
- Ågren, Karin, et al.
(författare)
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Detection of currents and associated electric fields in Titan's ionosphere from Cassini data
- 2011
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Ingår i: Journal of Geophysical Research. - 0148-0227 .- 2156-2202. ; 116:4, s. A04313-
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Tidskriftsartikel (refereegranskat)abstract
- We present observations from three Cassini flybys of Titan using data from the radio and plasma wave science, magnetometer and plasma spectrometer instruments. We combine magnetic field and cold plasma measurements with calculated conductivities and conclude that there are currents of the order of 10 to 100 nA m (2) flowing in the ionosphere of Titan. The currents below the exobase (similar to 1400 km) are principally field parallel and Hall in nature, while the Pedersen current is negligible in comparison. Associated with the currents are perpendicular electric fields ranging from 0.5 to 3 mu V m (1).
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| 14. |
- Ah-King, M., et al.
(författare)
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Why is there no sperm competition in a pipefish with externally brooding males? Insights from sperm activation and morphology
- 2006
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Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 68:3, s. 958-962
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Tidskriftsartikel (refereegranskat)abstract
- Nerophis ophidion sperm activation and morphology were investigated with the aim of explaining the apparent lack of sperm competition in this syngnathid with externally brooding males. Nerophis ophidion sperm were activated by a mixture of ovarian fluid and sea water, but not by sea water alone. This indicated that sperm were not shed into the water but needed to be released near the eggs, which probably restrained sperm competition. (c) 2006 The Fisheries Society of the British Isles.
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| 17. |
- Aronsen, T., et al.
(författare)
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The operational sex ratio and density influence spatial relationships between breeding pipefish
- 2013
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Ingår i: Behavioral Ecology. - : Oxford University Press (OUP). - 1045-2249 .- 1465-7279. ; 24:4, s. 888-897
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Tidskriftsartikel (refereegranskat)abstract
- The operational sex ratio (ratio of sexually receptive males to females) has been extensively studied in behavioral ecology, whereas other demographic factors such as the effect of density on mating behavior have received less empirical attention. We manipulated mating competition by establishing breeding populations of the sex-role reversed broad-nosed pipefish (Syngnathus typhle) at 2 sex ratios (male biased or female biased) and 2 densities. We used mean crowding (m*) and the index of association (X) to measure spatial distributions within and between the sexes, respectively, and investigated how these measures reflect the predicted strength of mating competition. In general, female m* increased as fewer males were available for mating, which suggests increased intrasexual competition in the most competitive sex. However, male m* also increased as the operational sex ratio became more female biased, suggesting that m* did not reflect mating competition for males. Association between the sexes (X) was higher under male bias than female bias, probably because males were still available for mating under male bias. In addition, X decreased in the female-biased treatment as the operational sex ratio became even more female biased. Higher density increased m* in both sex ratios and sexes, although for both sexes in the female-biased high-density treatment the operational sex ratio did not influence m*, probably because femalefemale competition inhibits further crowding in this treatment. In this study, we show that the use of m* and X can be a useful tool in behavioral studies but their interpretation requires detailed information about the mating system. Therefore, we recommend caution with their broadscale application.
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| 20. |
- Bastholm Rahmner, Pia, et al.
(författare)
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Physicians perceptions of possibilities and obstacles prior to implementing a computerised drug prescribing support system
- 2004
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Ingår i: International journal of health care quality assurance incorporating leadership in helath services. - : Emerald. - 1366-0756 .- 2051-3135. ; 17:4, s. 173-179
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Tidskriftsartikel (refereegranskat)abstract
- Seeks to identify physicians' perceptions of possibilities and obstacles prior to implementing a computerised drug prescribing support system. Details a descriptive, qualitative study, with semi-structured individual interviews of 21 physicians in the Accident and Emergency Department of South Stockholm General Hospital. Identifies four descriptive categories for possibilities and obstacles. Concludes that gaining access to patient drug history enables physicians to carry out work in a professional way – a need the computerised prescription support system was not developed for and thus cannot fulfil. Alerts and producer-independent drug information are valuable in reducing workload. However, technical prerequisites form the base for a successful implementation. Time must be given to adapt to new ways of working.
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| 21. |
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| 22. |
- Berglund, A, et al.
(författare)
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Ornamentation predicts reproductive success in female pipefish
- 1997
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Ingår i: BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY. - : SPRINGER VERLAG. - 0340-5443. ; 40:3, s. 145-150
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- In the sex-role reversed pipefish Syngnathus typhle females compete for access to males and males are choosy. Females develop a temporary ornament when competing over mates with other females and when performing nuptial dances with males. This ornament is
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| 23. |
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| 24. |
- Borg, Åsa A., et al.
(författare)
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Presence of same sex individuals negatively affects egg maturation in female guppies (Poecilia reticulata)
- 2006
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Ingår i: Behaviour. - : Brill. - 0005-7959 .- 1568-539X. ; 143, s. 747-761
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Tidskriftsartikel (refereegranskat)abstract
- Competition with individuals of the same sex may affect reproduction, and the effect may depend on own competitive ability. We exposed individual guppy (Poecilia reticulata) females either to larger females, smaller females or held them alone for five weeks. All replicates had visual access to a sexually mature mate. At the end of the experiment, there were no significant differences in daily growth or mass between the three treatments. However, females held alone had a higher reproductive output (in terms of ovary weight and GSI) than females held with either larger or smaller companions. This was mainly caused by a higher number of fully developed eggs in the ovaries of these females. The total number of eggs (including all stages) did not differ between the treatments. We suggest that the 'extra' energy not used in reproduction in the competitive treatments might have been spent on interactions between the females. In guppies socialising with other females seems to impose a cost on female reproduction.
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| 25. |
- Brännäs, Kurt, et al.
(författare)
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Semiparametric estimation of heterogeneous count data models
- 1994
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Ingår i: European Journal of Operational Research. - : Elsevier BV. - 0377-2217 .- 1872-6860. ; 76:2, s. 247-258
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Tidskriftsartikel (refereegranskat)abstract
- Unobserved heterogeneity in a stochastic model is usually represented by a mixing distribution. In this paper a semiparametric estimator is adapted to over-dispersed Poisson regression models. No assumptions are needed about the estimated mixing distribution. The parameters of included explanatory variables are estimated at the same time. The applicability and promising properties of the method are illustrated. Empirically the estimator is applied to a coffee purchase model and to a business travel frequency model subject to zero truncation. The approach is useful, e.g., in marketing research where socio-demographic variables as well as marketing instruments can be included as explanatory variables.
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| 26. |
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| 27. |
- Devlin, Yuka, et al.
(författare)
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On site landfill leachate treatment : investigations into economical and environmental sustainable systmes for Northern Ireland
- 2017
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Ingår i: Ebook: Proceedings of 11th European Waste Water Management Conference.
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Konferensbidrag (populärvet., debatt m.m.)abstract
- This paper presents the potential for the Swedish Laqua system to be used as a sustainable method for on-site landfill leachate management in Northern Ireland, specifically the potential to use locally sourced filter materials from Northern Ireland as part of the filter system. Four carbon containing ashes and four types of peat were tested over a 24 hours period by a shaking test with untreated landfill leachate. Considering the results of this screening test, and the economical and sustainable supply of filter materials, one combination of ash and peat was selected to be column tested. Column testing with artificial leachate containing 7 organic pollutants (3 PAHs and 4 PCBs) and 9 inorganic pollutants showed that locally sourced filter materials effectively removed both organic and inorganic pollutants. A subsequent column test with landfill leachate for 13 weeks demonstrated it was feasible to apply the Laqua system with economical locally sourced filter materials.
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| 28. |
- Devlin, Yuka, et al.
(författare)
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On site landfill leachate treatment : investigations into economical and environmental sustainable systmes for Northern Ireland
- 2017
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents the potential for the Swedish Laqua system to be used as a sustainable method for on-site landfill leachate management in Northern Ireland, specifically the potential to use locally sourced filter materials from Northern Ireland as part of the filter system. Four carbon containing ashes and four types of peat were tested over a 24 hours period by a shaking test with untreated landfill leachate. Considering the results of this screening test, and the economical and sustainable supply of filter materials, one combination of ash and peat was selected to be column tested. Column testing with artificial leachate containing 7 organic pollutants (3 PAHs and 4 PCBs) and 9 inorganic pollutants showed that locally sourced filter materials effectively removed both organic and inorganic pollutants. A subsequent column test with landfill leachate for 13 weeks demonstrated it was feasible to apply the Laqua system with economical locally sourced filter materials.
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| 29. |
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| 30. |
- FITZPATRICK, S, et al.
(författare)
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ORNAMENTS OR OFFSPRING - COSTS TO REPRODUCTIVE SUCCESS RESTRICT SEXUAL SELECTION PROCESSES
- 1995
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Ingår i: BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY. - : ACADEMIC PRESS (LONDON) LTD. - 0024-4066. ; 55:3, s. 251-260
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- If, in their partner choice, males seek direct benefits (fecund females), the result will be selection for traits indicating female quality rather than for arbitrary (Fisherian) traits. However, the costs of developing and maintaining the sexually selecte
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| 31. |
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| 32. |
- Flanagan, Sarah P., et al.
(författare)
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Mate quality and the temporal dynamics of breeding in a sex-role-reversed pipefish, S. typhle
- 2017
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 71:1
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Tidskriftsartikel (refereegranskat)abstract
- The spatiotemporal dynamics of receptivity and breeding date, coupled with individual-level quality and attractiveness, are centrally important to mating system dynamics. These topics have been investigated in some detail in birds, but much less work has been devoted to other taxonomic groups, and almost no work has addressed spatiotemporal factors and individual quality in sex-role-reversed taxa. The broad-nosed pipefish, Syngnathus typhle, provides an excellent opportunity to investigate these ideas in a sex-role-reversed fish. Here, we addressed three questions related to mating dynamics in S. typhle: (1) Do higher-quality males arrive earlier on the breeding grounds and mate first? (2) Are early-breeding males in better condition than later-breeding males? And (3) do mating events involving higher-quality males produce better clutches than mating events involving lower-quality males? We collected data from a field study and a laboratory breeding experiment to address our hypotheses. Our results show that larger males mate earlier than smaller males and that pregnant males have higher measures of condition compared to non-pregnant males. Moreover, our laboratory results demonstrate that pairings between larger males and preferred females yielded more offspring than pairings involving smaller males. In summary, the spatiotemporal dynamics of S. typhle breeding patterns, combined with variation in individual quality, play an important role in shaping mating systems and should be incorporated in future analyses of mating behavior and sexual selection in this interesting sex-role-reversed pipefish. Significance statement The breeding patterns of a species can fluctuate over time due to a number of factors, one of which is individual quality. Although the effects of both the timing of reproduction and female quality on mating systems have been studied in some species, they have been investigated primarily in isolation. Here, we demonstrate that individual quality and the timing of reproduction interact to affect reproductive success in a wild population of sex-role-reversed fish.
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| 33. |
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| 34. |
- Freedman, Ben, et al.
(författare)
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Screening for Atrial Fibrillation A Report of the AF-SCREEN International Collaboration
- 2017
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Ingår i: Circulation. - : LIPPINCOTT WILLIAMS & WILKINS. - 0009-7322 .- 1524-4539. ; 135:19, s. 1851-
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Tidskriftsartikel (refereegranskat)abstract
- Approximately 10% of ischemic strokes are associated with atrial fibrillation (AF) first diagnosed at the time of stroke. Detecting asymptomatic AF would provide an opportunity to prevent these strokes by instituting appropriate anticoagulation. The AF-SCREEN international collaboration was formed in September 2015 to promote discussion and research about AF screening as a strategy to reduce stroke and death and to provide advocacy for implementation of country-specific AF screening programs. During 2016, 60 expert members of AF-SCREEN, including physicians, nurses, allied health professionals, health economists, and patient advocates, were invited to prepare sections of a draft document. In August 2016, 51 members met in Rome to discuss the draft document and consider the key points arising from it using a Delphi process. These key points emphasize that screen-detected AF found at a single timepoint or by intermittent ECG recordings over 2 weeks is not a benign condition and, with additional stroke factors, carries sufficient risk of stroke to justify consideration of anticoagulation. With regard to the methods of mass screening, handheld ECG devices have the advantage of providing a verifiable ECG trace that guidelines require for AF diagnosis and would therefore be preferred as screening tools. Certain patient groups, such as those with recent embolic stroke of uncertain source (ESUS), require more intensive monitoring for AF. Settings for screening include various venues in both the community and the clinic, but they must be linked to a pathway for appropriate diagnosis and management for screening to be effective. It is recognized that health resources vary widely between countries and health systems, so the setting for AF screening should be both country-and health system-specific. Based on current knowledge, this white paper provides a strong case for AF screening now while recognizing that large randomized outcomes studies would be helpful to strengthen the evidence base.
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| 35. |
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| 36. |
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| 37. |
- Henriksen, Eva, et al.
(författare)
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Can we bridge the gap between goals and practice through a common vision? : a study of politicians and managers’ understanding of the provisions of elderly care services
- 2003
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Ingår i: Health Policy. - 0168-8510 .- 1872-6054. ; 65:2, s. 129-137
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to identify and describe how local politicians and managers experience and understand problems and goals regarding the structures and processes involved in the care of the elderly. Qualitative methodology of a conceptual modelling workshop was used. Participants were healthcare politicians, local municipal politicians, and executive care managers. The main result was that all participants agreed on four key visions for the healthcare of the elderly: see the person, see the individual's resources, see the encounter, and see yourself. Other findings indicated that (a) care of older persons was governed by diverse interests, (b) the organisation lacked clear leadership and comprehensive goals, (c) the organisation was fragmented, and (d) there was a lack of skilled staff members to meet patient needs. Older persons were regarded as passive receivers of care or as objects that did not take an active part in health care decisions that affect them.
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| 38. |
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| 39. |
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| 40. |
- Jiang, Jingxiong, et al.
(författare)
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The effects of a 3-year obesity intervention in schoolchildren in Beijing
- 2007
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Ingår i: Child: Care, Health and Development. - : Wiley. - 0305-1862 .- 1365-2214. ; 33:5, s. 641-646
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Tidskriftsartikel (refereegranskat)abstract
- Background: Childhood obesity has become a health problem in urban areas in China. Intervention to reduce childhood obesity should be of high priority. School-based intervention programmes are needed to deal with the growing prevalence of childhood obesity in China. Methods: Five primary schools were selected randomly for this study in the Beijing urban area in China; two were allocated to the intervention group and three to the control group. A total of 2425 children (1029 children in intervention schools and 1396 children in control schools) took part in the study for 3 years. In the intervention group, children and their parents were involved in a programme of nutrition education and physical activity. Control school students followed their usual health and physical education curriculum with no extra intervention. Results: After the 3-year intervention, the prevalence of overweight and obesity were significantly lower in the intervention schools than in the control schools (overweight: 9.8% vs. 14.4%, P < 0.01; obesity: 7.9% vs. 13.3%, P < 0.01). The prevalence of overweight and obesity decreased by 26.3% and 32.5% in intervention schools respectively after intervention. The prevalence of overweight and obesity increased in control schools. There was also significant difference in body mass index between intervention and control schools (18.2 ± 2.6 vs. 20.3 ± 3.4, P < 0.01) after intervention. More non-obese children became obese in the control schools (7.0%) than in the intervention schools (2.4%) at end line (P < 0.01). Among the children who were obese at baseline, 49.2% remained obese at end line in intervention schools while 61.9% remained obese in control schools (P < 0.01). Conclusions: Our study showed that an intervention programme could be feasible in schools in Beijing, China. The prevalence of overweight and obesity was reduced in schoolchildren in Beijing through an intervention focused on nutrition education and physical activity. Overweight and obesity children as well as normal weight children and their parents should be involved in such an intervention programme.
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| 41. |
- Jones, Adam G., et al.
(författare)
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Clustered microsatellite mutations in the pipefish Syngnathus typhle
- 1999
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Ingår i: Genetics. - 0016-6731 .- 1943-2631. ; 152:3, s. 1057-1063
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Tidskriftsartikel (refereegranskat)abstract
- Clustered mutations are copies of a mutant allele that enter a population's gene pool together due to replication fi om a premeiotic germline mutation and distribution to multiple successful gametes of an individual. Although the phenomenon has been studied in Drosophila and noted in a few other species, the topic has received scant attention despite claims of being of major importance to population genetics theor). Here we capitalize upon the reproductive biology of male-pregnant pipefishes to document the occurrence of clustered microsatellite mutations and to estimate their rates and patterns from family data. Among a total of 3195 embryos genetically screened from 110 families, 40% of the 35 detected de novo mutant alleles resided in documented mutational clusters. Most of the microsatellite mutations appeared to involve small-integer changes ill repeat copy number, and they arose in approximately equal frequency in paternal and maternal germlines. These findings extend observations on clustered mutations to another organismal group and motivate a broader critique of the mutation cluster phenomenon. They also carry implications for the evolution of microsatellites with respect to mutational models and homoplasty among alleles.
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| 42. |
- Jones, Adam G., et al.
(författare)
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Mate quality influences multiple maternity in the sex-role-reversed pipefish Syngnathus typhle
- 2000
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Ingår i: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 90:2, s. 321-326
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Tidskriftsartikel (refereegranskat)abstract
- In the pipefish Syngnathus typhle, pregnant males provide all parental care. Females are able to produce more eggs than males can brood, and consequently females compete more intensely for mates than do males, a phenomenon defined as sex-role reversal. As the genetic mating system influences the operation of sexual selection, we investigate variation in one phenotypic component of mate quality, female body size, as a possible proximate influence on mating system variation in S. typhle. Breeding trials were employed, each consisting of a single receptive male with four adult females. In each replicate, a focal male was paired either with a set of small or with a set of large females. Males were allowed to mate freely, and after several weeks of brood development, maternity of the progeny was resolved using three microsatellite loci. Males with access either to small or to large females successfully mated with a mean of 2.1 or 1.3 females, respectively, a significant difference. Results indicate that variation in female size can affect the mating system and thereby influence sexual selection in pipefish. Thus, the high rate of multiple mating by S. typhle males in the wild may be explained in part by the extensive size variation in naturally occurring, sexually mature females.
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| 43. |
- Jones, Adam G., et al.
(författare)
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The Bateman gradient and the cause of sexual selection in a sex-role-reversed pipefish
- 2000
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 267:1444, s. 677-680
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Tidskriftsartikel (refereegranskat)abstract
- As a conspicuous evolutionary mechanism, sexual selection has received much attention from theorists and empiricists. Although the importance of the mating system to sexual selection has long been appreciated, the precise relationship remains obscure. In a classic experimental study based on parentage assessment using visible genetic markers, more than 50 years ago A. J. Bateman proposed that the cause of sexual selection in Drosophila is ‘the stronger correlation, in males (relative to females), between number of mates and fertility (number of progeny)’. Half a century later, molecular genetic techniques for assigning parentage now permit mirror–image experimental tests of the ‘Bateman gradient’ using sex–role–reversed species. Here we show that, in the male–pregnant pipefish Syngnathus typhle, females exhibit a stronger positive association between number of mates and fertility than do males and that this relationship responds in the predicted fashion to changes in the adult sex ratio. These findings give empirical support to the idea that the relationship between mating success and number of progeny, as characterized by the Bateman gradient, is a central feature of the genetic mating system affecting the strength and direction of sexual selection.
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| 44. |
- Jones, Adam G., et al.
(författare)
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The genetic mating system of a sex-role-reversed pipefish (Syngnathus typhle) : a molecular inquiry
- 1999
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 46:5, s. 357-365
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Tidskriftsartikel (refereegranskat)abstract
- In the pipefish Syngnathus typhle as in other species of Syngnathidae, developing embryos are reared on the male's ventral surface. Although much laboratory research has been directed toward understanding sexual selection in this sex-role-reversed species, few studies have addressed the mating behavior of S. typhle in the wild, and none has capitalized upon the power of molecular genetic assays. Here we present the first direct assessment of the genetic mating system of S. typhle in nature. Novel microsatellite loci were cloned and characterized from this species, and employed to assay entire broods from 30 pregnant, field-captured males. Genetic analysis of 1340 embryos revealed that 1-6 females (mean = 3.1) contributed to each brooded clutch, the highest rate of multiple maternity yet documented in any pipefish. Evidence of multiple mating by females was also detected. Thus, this population of S. typhle displays a polygynandrous mating system, a finding consistent with previous field and laboratory observations. Our results, considered together with similar studies of other syngnathid species, provide preliminary support for the hypothesis that the genetic mating system is related to the evolution of sexual dimorphism in the fish family Syngnathidae.
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| 45. |
- Jones, Adam G., et al.
(författare)
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The measurement of sexual selection using Bateman's principles : An experimental test in the sex-role-reversed pipefish Syngnathus typhle
- 2005
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Ingår i: Integrative and Comparative Biology. - : Oxford University Press (OUP). - 1540-7063 .- 1557-7023. ; 45:5, s. 874-884
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Tidskriftsartikel (refereegranskat)abstract
- Angus J. Bateman's classic study of sexual selection in Drosophila melanogaster has had a major influence on the development of sexual selection theory. In some ways, Bateman's study has served a catalytic role by stimulating debate on sex roles, sexual conflict and other topics in sexual selection. However, there is still considerable disagreement regarding whether or not "Bateman's principles" are helpful in the study of sexual selection. Here, we test the idea that Bateman's principles provide the basis for a useful method to quantify and compare mating systems. In this study, we focus on the sex-role-reversed pipefish Syngnathus typhle as a model system to study the measurement of sexual selection. We set up artificial breeding assemblages of pipefish in the laboratory and used microsatellite markers to resolve parentage. Three different sex-ratio treatments (female-biased, even and male-biased) were used to manipulate the expected intensity of sexual selection. Measures of the mating system based on Bateman's principles were calculated and compared to the expected changes in the intensity of sexual selection. We also compare the results of this study to the results of a similar study of Bateman's principles in the rough-skinned newt, a species with conventional sex roles. The results of this experiment show that measures of the mating system based on Bateman's principles do accurately capture the relative intensities of sexual selection in the different treatments and species. Thus, widespread use of Bateman's principles to quantify mating systems in nature would facilitate comparative studies of sexual selection and mating system evolution.
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| 46. |
- Jones, AG, et al.
(författare)
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The genetic mating system of a sex-role-reversed pipefish (Syngnathus typhle): a molecular inquiry
- 1999
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Ingår i: BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY. - : SPRINGER VERLAG. - 0340-5443. ; 46:5, s. 357-365
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- In the pipefish Syngnathus typhle as in other species of Syngnathidae, developing embryos are reared on the male's ventral surface. Although much laboratory research has been directed toward understanding sexual selection in this sex-role-reversed species
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| 47. |
- Jonsson, PM, et al.
(författare)
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Diabetes mellitus and health service utilization : a case-control study of outpatient visits 8 years after diagnosis
- 1996
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Ingår i: Diabetic Medicine. - 0742-3071 .- 1464-5491. ; 13, s. 1056-1063
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Tidskriftsartikel (refereegranskat)abstract
- All incident cases of diabetes mellitus in the age group 15 to 34 years have been prospectively registered in Sweden since January 1983. To analyse the utilization of outpatient services 8 years after disease onset, we selected the cases registered in 1983 and two controls per case from the general population, matched by age, gender, and county of residence. In 1991, retrospective data about utilization patterns during a 3-month period were collected via a mailed questionnaire, returned by 317 (72%) patients with diabetes and 586 (68%) controls. Seventy-four percent of the cases and 19% of the controls reported at least one visit to a hospital outpatient clinic, including accident and emergency departments. The odds ratio for one visit was 14 (95% CI 9.6-20), for two visits 11 (95% CI 7.0-18), and for three or more visits 8.9 (95% CI 5.6-14). Even when specialized diabetes clinics were excluded from the analysis, the cases had higher odds for visits to internal medicine clinics, to ophthalmology clinics, and to gynaecology clinics, but not for visits to surgical clinics or to accident and emergency departments. Of non-hospital outpatient services, only visits to nurse practitioners were reported by a higher percentage of diabetic responders. Twenty-seven percent of patients with diabetes, as compared to 9% of the controls, had visited both hospital and non-hospital outpatient offices. Females were overrepresented among diabetic high-consumers. The results indicate that most young to middle-aged Swedish persons with diabetes are monitored at hospital outpatient offices, but considerable overlap exists between hospital and non-hospital outpatient services. Further research is needed into the determinants of utilization patterns in diabetes, such as gender.
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| 48. |
- Krång, Anna Sara, 1972, et al.
(författare)
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Effects of manganese on chemically induced food search behaviour of the Norway lobster, Nephrops norvegicus (L.)
- 2006
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Ingår i: Aquatic Toxicology. - : Elsevier BV. - 0166-445X. ; 78:3, s. 284-291
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Tidskriftsartikel (refereegranskat)abstract
- The decapod Norway lobster, Nephrops norvegicus (L.), lives on muddy sediments rich in manganese (Mn). In hypoxic conditions, manganese is reduced and released from the sediment, so increased concentrations of dissolved Mn2+ become bioavailable. In excess, manganese acts as a neurotoxin and may inhibit vital functions of benthic organisms, such as muscle contraction. We investigated in a laboratory flume experiment, the effect of environmentally realistic concentrations of manganese (0.1 and 0.2 mM for 12 days) on the food search behaviour of N. norvegicus. We found that lobsters exposed to manganese had a more than doubled reaction time to food odour stimuli compared to the controls (p < 0.05). In addition, manganese exposure reduced the number of N. norvegicus reaching the food stimuli source. Compared to the controls where 86% reached the stimuli source, only about half of the lobsters exposed to 0.1 mM Mn and one-third of the lobsters exposed to 0.2 MM Mn reached the stimuli source (p < 0.05 and 0.001, respectively). There was no significant difference between treatments in the number of lobsters leaving their shelter or in the time from reaction until leaving the shelter and there was no difference in search time for those animals that eventually did locate the stimuli source. This study shows that environmentally realistic manganese concentrations affect parts of the food search behaviour of N. norvegicus, likely due to impaired chemosensory ability or reduced motivation for feeding. Thus, the ability of N. norvegicus to detect and find food can be reduced in areas with high manganese concentrations, with possible consequences on individual and population levels. (c) 2006 Elsevier B.V. All rights reserved.
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| 49. |
- Langhamer, Olivia, 1977, et al.
(författare)
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Effect of an offshore wind farm on the viviparous eelpout: Biometrics, brood development and population studies in Lillgrund, Sweden
- 2018
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Ingår i: Ecological Indicators. - : Elsevier BV. - 1470-160X .- 1872-7034. ; 84, s. 1-6
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Tidskriftsartikel (refereegranskat)abstract
- Sufficient, clean and secure energy is the main driver for a worldwide growing welfare and economic development of a society. Environmental concerns on the expansion of offshore renewable energy and its impact on marine organisms need to be scientifically assessed for risks and consequences. In order to observe the effects of an operating wind farm on fish, we studied the rather stationary and benthic-living fish species viviparous eelpout (Zoarces viviparous) as model indicator organisms. We compared local populations of viviparous eelpout in the Lillgrund Offshore Wind Farm (OWF) with natural sites in the Öresund strait in Sweden. Eelpout studies on population dynamics, biometrics, reproductive success and fry development were conducted in 2011 and 2012. Condition index, histosomatic index, gonadosomatic index were measured additionally. Our findings showed that Lillgrund OWF neither had an impact on the condition index (CI), nor on brood development of female viviparous eelpout. Furthermore, populations size estimates in Lillgrund indicated that eelpout neither specifically aggregated in nor avoided the offshore wind farm, and no clear reef effect attracting eelpout to the foundations and scour protections of the OWF was observed. Our conclusion is that the operating wind farm did not have any potentially negative effects, since we did not observe any negative effects neither on the individual health of eelpout nor of the reproductive performance. We suggest that eelpout which may also be used as an indicator species for the environmental status of Lillgrund, as well as for other offshore wind farms and marine renewable energy installations, both in the Baltic and coastal waters in northern Europe. © 2017 Elsevier Ltd
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