| 1. |
- Abalaka, Jacinta, et al.
(författare)
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Genetic diversity and population structure of the range restricted rock firefinch Lagonosticta sanguinodorsalis
- 2015
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Ingår i: Conservation Genetics. - : Springer Science and Business Media LLC. - 1566-0621 .- 1572-9737. ; 16:2, s. 411-418
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the degree of genetic population differentiation is important in conservation genetics for inferring gene flow between populations and for identifying small and isolated threatened populations. We evaluated the genetic variation within and between three populations of the rock firefinch (Lagonosticta sanguinodorsalis), a range restricted firefinch endemic to Nigeria and Cameroon. The populations were closely located (c. 100 km apart) within the species' core distribution in Central Nigeria. We found that the populations had similar levels of gene diversities (H (E) ) and low but significant inbreeding coefficients (F (IS) ). Despite the short distance between populations there was a weak but significant population structure, which indicates that the populations are somewhat isolated and affected by drift within the species' core distribution in Nigeria. The knowledge of the genetic status of the rock firefinch will serve as a foundation to future studies to help understand population demography and for managing and maintaining viable populations.
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| 2. |
- Iwajomo, Soladoye B., et al.
(författare)
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Intra-African movements of the African cuckoo Cuculus gularis as revealed by satellite telemetry
- 2018
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Ingår i: Journal of Avian Biology. - : Wiley. - 0908-8857. ; 49:1
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Tidskriftsartikel (refereegranskat)abstract
- Despite many bird species migrating regularly within the African continent, in response to rainfall and breeding opportunities, documented evidence of the spatiotemporal patterns of such movements is scarce. We use satellite telemetry to document the year round movement of an intra-African migrant breeding in the savannah zone of sub-Saharan Africa, the African cuckoo. After breeding in central Nigeria, the birds migrated to more forested sites in the Adamawa region of Cameroon (n = 2) and western Central African Republic (n = 1). Departure from the breeding ground coincided with deteriorating environmental conditions whereas arrival at the non-breeding sites matched period of increasing vegetation greenness. Migratory movements generally occurred during dark hours. In total, an average distance of 748 km in 66 d was covered during the post-breeding migration and 744 km in 27 d during return journey with considerable individual variation and with more stopover sites used during post-breeding migration. The diversity of migration routes followed suggests a relatively variable or flexible initial migration strategy, high individual route consistency as well as high fidelity for non-breeding grounds.
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| 3. |
- Lundbäck, Peter, et al.
(författare)
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A novel high mobility group box 1 neutralizing chimeric antibody attenuates drug-induced liver injury and postinjury inflammation in mice
- 2016
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Ingår i: Hepatology. - : Ovid Technologies (Wolters Kluwer Health). - 0270-9139 .- 1527-3350. ; 64:5, s. 1699-1710
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Tidskriftsartikel (refereegranskat)abstract
- Acetaminophen (APAP) overdoses are of major clinical concern. Growing evidence underlines a pathogenic contribution of sterile postinjury inflammation in APAP-induced acute liver injury (APAP-ALI) and justifies development of anti-inflammatory therapies with therapeutic efficacy beyond the therapeutic window of the only current treatment option, N-acetylcysteine (NAC). The inflammatory mediator, high mobility group box 1 (HMGB1), is a key regulator of a range of liver injury conditions and is elevated in clinical and preclinical APAP-ALI. The anti-HMGB1 antibody (m2G7) is therapeutically beneficial in multiple inflammatory conditions, and anti-HMGB1 polyclonal antibody treatment improves survival in a model of APAP-ALI. Herein, we developed and investigated the therapeutic efficacy of a partly humanized anti-HMGB1 monoclonal antibody (mAb; h2G7) and identified its mechanism of action in preclinical APAP-ALI. The mouse anti-HMGB1 mAb (m2G7) was partly humanized (h2G7) by merging variable domains of m2G7 with human antibody-Fc backbones. Effector function-deficient variants of h2G7 were assessed in comparison with h2G7 in vitro and in preclinical APAP-ALI. h2G7 retained identical antigen specificity and comparable affinity as m2G7. 2G7 treatments significantly attenuated APAP-induced serum elevations of alanine aminotransferase and microRNA-122 and completely abrogated markers of APAP-induced inflammation (tumor necrosis factor, monocyte chemoattractant protein 1, and chemokine [C-X-C motif] ligand 1) with prolonged therapeutic efficacy as compared to NAC. Removal of complement and/or Fc receptor binding did not affect h2G7 efficacy. Conclusion: This is the first report describing the generation of a partly humanized HMGB1-neutralizing antibody with validated therapeutic efficacy and with a prolonged therapeutic window, as compared to NAC, in APAP-ALI. The therapeutic effect was mediated by HMGB1 neutralization and attenuation of postinjury inflammation. These results represent important progress toward clinical implementation of HMGB1-specific therapy as a means to treat APAP-ALI and other inflammatory conditions. (Hepatology 2016;64:1699-1710).
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| 4. |
- Mao, Fang, et al.
(författare)
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Combinatorial Study of Gradient Ag-Al Thin Films : Microstructure, Phase Formation, Mechanical and Electrical Properties
- 2016
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 8:44, s. 30635-30643
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Tidskriftsartikel (refereegranskat)abstract
- A combinatorial approach is applied to rapidly deposit and screen Ag-Al thin films-to evaluate the mechanical, tribological, and electrical properties as a function of chemical composition. Ag-Al thin films with large continuous composition gradients (6-60 atom % Al) were deposited by a custom-designed combinatorial magnetron sputtering system. X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), scanning and transmission electron microscopy (SEM and TEM), X-ray photoelectron spectroscopy (XPS), nanoindentation, and four-point electrical resistance screening were employed to characterize the chemical composition, structure, and physical properties of the films in a time-efficient way. For low Al contents (<13 atom %), a highly (111)-textured fcc phase was formed. At higher Al contents, a (002)-textured hcp solid solution phase was formed followed by a fcc phase in the most At-rich regions. No indication of a mu phase was observed. The Ag-Al films with fcc-Ag matrix is prone to adhesive material transfer leading to a high friction coefficient (>1) and adhesive wear, similar to the behavior of pure Ag. In contrast, the hexagonal solid solution phase (from ca. 15 atom %Al) exhibited dramatically reduced friction coefficients (about 15% of that of the fcc phase) and dramatically reduced adhesive wear when tested against the pure Ag counter surface. The increase in contact resistance of the Ag Al films is limited to only 50% higher than a pure Ag reference sample at the low friction and low wear region (19-27 atom %). This suggests that a hcp Ag Al alloy can have a potential use in sliding electrical contact applications and in the future will replace pure Ag in specific electromechanical applications.
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| 5. |
- Olsson, Ola, et al.
(författare)
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Competition, seed dispersal and hunting : What drives germination and seedling survival in an Afrotropical forest?
- 2019
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Ingår i: AoB Plants. - : Oxford University Press (OUP). - 2041-2851. ; 11:2
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Tidskriftsartikel (refereegranskat)abstract
- Disentangling the contributions of different processes that influence plant recruitment, such as competition and seed dispersal, is important given the increased human-mediated changes in tropical forest ecosystems. Previous studies have shown that seedling communities in an Afrotropical rainforest in southeastern Nigeria are strongly affected by the loss of important seed-dispersing primates, including Cross River gorillas (Gorilla gorilla diehli), chimpanzee (Pan troglodytes elioti) and drill (Mandrillus leucophaeus). Here we study how germination and survival of tree seedlings are affected by competition and reduced seed dispersal in three contiguous forest reserves, in southeastern Nigeria, with similar mature tree species composition and structure. We use an experimental design aimed at manipulating the effect of competition among seedlings in three protected and three hunted sites within the reserves. We use a total of sixty 5 × 5 m plots of three types: plots cleared of all seedlings, plots selectively cleared of all primate-dispersed seedlings and control plots. All seedlings were identified, measured, assigned to dispersal mode and tagged, and after 1 year we evaluated survival, mortality and new recruits. We found that in hunted sites germination of abiotically dispersed species was over four times higher in cleared plots compared to control plots, whereas germination of primate-dispersed species was the same, which indicated that dispersal limitation was the dominant force in seedling recruitment in hunted sites. This was supported by the fact that the germination of all dispersal modes in the selectively cleared plots in protected sites was similar to the control plots in the same sites, but germination of abiotically dispersed species was significantly lower than in cleared plots in hunted sites. Competition among seedlings was mostly evident from the fact that 75 % more seedlings of primate-dispersed species germinated in cleared compared to control plots in protected sites. We conclude that inter-seedling competition may be irrelevant to seedling recruitment in hunted sites, where dispersal limitation appears to be a much stronger force shaping the seedling plant community, and thus hunting indirectly reverses the importance of competition and dispersal limitation in structuring seedling communities.
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| 6. |
- Richard, Ottvall, et al.
(författare)
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Strandängsfåglar Rapport från gemensamt delprogram täckande perioden 1988-2018
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Populationstrender för fåglar på havsstrandängar i sju län analyserades för perioden 1988–2018. För 27 arter där en trend kunde beräknas för hela perioden var bestånden minskande för 13 arter, ökande för 8 arter och för 6 arter fanns ingen säker förändring. Vid analys för perioden 2003–2018 kunde trender beräknas för 38 arter och bestånden var minskande för 18 arter, ökande för 10 arter och oförändrade för 10 arter. För några arter, t.ex. svärta och svartbent strandpipare, kunde inga trender beräknas för hela den analyserade perioden då ingen av arterna längre bokförs årligen vid inventeringarna.I stort sett har det gått bra för gäss, måsar, trutar och tärnor, men sämre för änder, vadare och sydlig gulärla. Svärta, sydlig kärrsnäppa och roskarl är på väg att försvinna från havsstrandängar. Svartbent strandpipare försvann under den analyserade perioden. Omkring hälften av strandängsarterna uppvisade populationsminskningar de senaste 15 åren, men det finns några ljusglimtar där trenderna inte är lika negativa i alla regioner. De hotade arterna brushane och rödspov har ökat från låga nivåer och på Öland går det överlag bättre för flera vadare än vad det gör i övriga regioner med havsstrandängar. Detta gäller dock inte strandskata, roskarl och storspov som fortsätter att minska även på Öland. Änder, med undantag av snatterand, uppvisar mer negativa trender på Öland och Gotland än i övriga regioner.Arter som ökade perioden 2003–2018 var grågås, vitkindad gås, snatterand, storskrake, brushane, silltrut (västlig – intermedius), skrattmås, silvertärna och småtärna. Arter utan säkra förändringar i antal var kanadagås, gräsand, kricka, större strandpipare, rödspov, skärfläcka, havstrut, fiskmås och fisktärna. Minskande arter var knölsvan, årta, stjärtand, skedand, vigg, ejder, småskrake, gravand, strandskata, tofsvipa, roskarl, enkelbeckasin, storspov, drillsnäppa, rödbena, sydlig kärrsnäppa, gråtrut och sydlig gulärla. Åtgärdsprogrammen för hotade vadare på strandängar föreslår biotopförbättrande åtgärder med återskapande av våtmarker som en viktig insats för att bevara vadare. En annan betydande insats är att kontrollera predatorer genom jakt. Sedan 2007 har våtmarker skapats och predatorer jagats på Öland. Dessutom drabbades ön av ett utbrott av rävskabb, vilket decimerade rävstammen kraftigt under flera år. Predationen på vadarnas ägg har minskat på Öland och det är möjligt att utvärdera populationstrenderna på Öland i jämförelse med de på Gotland där inga liknande åtgärder har genomförts under samma tidsperiod. Under perioden 2006–2018 uppvisade sju av 24 jämförbara arttrender en mer positiv trend på Öland, medan det omvända, att en mer positiv trend fanns på Gotland, inte observerades alls. Skedand, strandskata, tofsvipa, större strandpipare, enkelbeckasin, rödbena och småtärna hade samtliga en mer positiv trend på Öland. Stora sammanhängande arealer av havsstrandängar på Öland tillsammans med rävskabb och omfattande åtgärder med predatorkontroll och biotopförbättring kan vara de faktorer som ligger bakom den mer positiva bilden för några strandängsfåglar på Öland jämfört med Gotland.Storspov och roskarl är arter som inte tycks svara på åtgärder på häckningsplatserna. Detta indikerar att faktorer under fåglarnas flyttning eller i övervintringsområden kan ligga bakom observerade minskningar.
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| 7. |
- Sundberg, Sebastian, et al.
(författare)
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Arter försvinner i rekordtakt, men ljuspunkter finns
- 2018
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Annan publikation (populärvet., debatt m.m.)abstract
- Flera vetenskapliga studier visar att jordens arter nu försvinner i en takt som inte haft någon motsvarighet under de senaste 66 miljoner åren. Men det finns ljuspunkter i form av negativa trender som har vänts under senare år, inte minst i Sverige.
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