| 1. |
- Loman, Jon
(författare)
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Growth and development of larval Rana temporaria: Local variation and countergradient selection
- 2003
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Ingår i: Journal of Herpetology. - 0022-1511. ; 37:3, s. 595-602
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Tidskriftsartikel (refereegranskat)abstract
- I raised tadpoles of the Common Frog (Rana temporaria) from populations in eight source ponds in southern Sweden, in a common garden experiment at two densities. Tadpoles from different populations differed in development rate; those from source ponds with high tadpole densities developed faster than those from less crowded ponds. Thus, differences among ponds in tadpole performance, which were documented in previous field studies, must have a genetic or maternal component. This result of source pond crowding likely resulted from microevolution and is an example of countergradient selection. In contrast, I found no significant effect of source pond hydroperiod; tadpoles from temporary ponds grew and developed at a rate similar to those from permanent ponds. Tadpoles of R. temporaria can respond plastically to pond drying by increasing development rate. I suggest adaptive plasticity in development rate decreased selection by pond drying in natural ponds.
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| 2. |
- Entiauspe-Neto, O. M., et al.
(författare)
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Taxonomic Status of Two Simultaneously Described Apostolepis Cope, 1862 Species (Dipsadidae: Elapomorphini) from Caatinga Enclaves Moist Forests, Brazil
- 2020
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Ingår i: Journal of Herpetology. - : Society for the Study of Amphibians and Reptiles. - 0022-1511. ; 54:2, s. 225-234
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Tidskriftsartikel (refereegranskat)abstract
- Apostolepis mariae and Apostolepis thalesdelemai are two simultaneously described Elapomorphini snake species for two mountain ranges of Caatinga Enclaves moist forests in the state of Ceara, northeastern Brazil. Both species were differentiated from congeners and from one another based exclusively on external morphology. We examined the type specimens as well as a comprehensive series of specimens for both species and provide evidence for the recognition of both taxa as conspecific. We apply Article 24.2.1 of the International Code of Zoological Nomenclature (ICZN) that provides guidelines for taxonomic status precedence for both species based on the principle of the first reviser decision. Based on the ICZN code, we gave precedence for A. thalesdelemai over A. mariae. Finally, we provide a complementary diagnosis for A. thalesdelemai along with comments on its geographic distribution, natural history, and conservation.
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| 3. |
- Forsman, A
(författare)
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Body size and net energy gain in gape-limited predators: A model
- 1996
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Ingår i: JOURNAL OF HERPETOLOGY. - : SOC STUD AMPHIBIANS REPTILES. - 0022-1511. ; 30:3, s. 307-319
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- In snakes and other predators that swallow their food whole, gape size sets an upper limit to ingestible prey size. Individuals that vary in body size and swallowing capacity will therefore differ not only in energy requirements but also in rates of food
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| 4. |
- Forsman, Anders, et al.
(författare)
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Do Scale Anomalies Cause Differential Survival in Vipera berus?
- 1994
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Ingår i: Journal of Herpetology. - 0022-1511 .- 1937-2418. ; 28:4, s. 435-440
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Tidskriftsartikel (refereegranskat)abstract
- Many snake populations contain moderate to high frequencies of individuals with ventral scale anomalies, which are often associated with duplicated or fused vertebrae and ribs and are known to impair locomotion and growth. In an attempt to test whether such anomalies may influence survival, we examined their frequency among cage-reared juvenile adders, Vipera berus, and wild-caught individuals that presumably had been exposed to natural selection. Midbody ventral scale anomalies were significantlyless frequent among snakes exposed to selection than among cage-reared juveniles in one of three populations studied, indicating that they might indeed reduce survival. Furthermorem, idbody anomalies wereless common among large than among small wild-caught individuals, although not significantly so. The association between anomalies among captive mothers and their offspring was very weak, indicating low heritability of this trait. This low heritability might explain why scale anomalies are common in adder populations in spite of the apparent selection against anomalous individuals. We also found the proportion of anomalous offspring to increase with litter size, suggesting a trade-off between number and quality of young.
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| 5. |
- Gustafson, Daniel H., et al.
(författare)
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Pond Quality Determinants of Occurrence Patterns of Great Crested Newts (Triturus cristatus)
- 2009
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Ingår i: Journal of Herpetology. - 0022-1511 .- 1937-2418. ; 43:2, s. 300-310
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Tidskriftsartikel (refereegranskat)abstract
- We used principal component analysis and logistic regression to evaluate the effect of 11 pond water quality variables on the presence and absence of Great Crested Newts (Triturus cristatus) in a cluster of 29 ponds in south-central Sweden. Variables of importance for the patterns observed were comprised into four principal components. Using logistic regression analysis and Akaike's Information Criteria (AIC) we found that the best model explaining the distribution of Great Crested Newts included three of the principal components. Temperature and nutrient levels (nitrogen and phosphorus) were important in distinguishing between ponds with and without Great Crested Newts, whereas other physical variables were less important. Ponds with newts had higher temperatures and nutrient levels than ponds where the species was absent. Our results also suggest that the Great Crested Newt selects ponds with low nutrient levels for breeding, whereas they may be present in ponds with higher nutrient levels. Although this study was performed in a single area with a limited sample the results raise several issues of general importance for the management and conservation of Great Crested Newts in pond landscapes.
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| 6. |
- Kahrl, Ariel F., et al.
(författare)
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Consistent Differences in Sperm Morphology and Testis Size between Native and Introduced Populations of Three Anolis Lizard Species
- 2017
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Ingår i: Journal of Herpetology. - : Society for the Study of Amphibians and Reptiles. - 0022-1511 .- 1937-2418. ; 51:4, s. 532-537
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Tidskriftsartikel (refereegranskat)abstract
- Sperm morphology can be highly variable among individuals and across species, but less is known about its variation among populations. Within the past 20-80 yr, several species of Anolis lizards have been introduced to Miami, Florida, USA from different source islands in the Caribbean, thereby permitting comparisons of sperm morphology between native and introduced populations of multiple species. We collected sperm samples from native populations of Anolis sagrei (Bahamas), Anolis distichus (Dominican Republic), and Anolis cristatellus (Puerto Rico) and compared them to samples from introduced populations of each species that are now sympatric in Miami. In each of these three species, lizards from introduced populations had sperm with shorter tails and larger midpieces relative to lizards from native populations. We also measured testis size in A. distichus and A. cristatellus and found that introduced populations of each species had smaller testes for a given body size relative to their native counterparts. The consistency of these differences across species argues against random genetic drift as an explanation, suggesting instead that sperm morphology and testis size may exhibit predictable phenotypic plasticity or genetic adaptation in response to the process of introduction and/or the shared local environment in Florida. Though these population differences in male reproductive physiology and morphology may be repeatable, their underlying causes require further study.
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| 7. |
- Önfelt, Björn, et al.
(författare)
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Cutting edge : Membrane nanotubes connect immune cells
- 2004
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Ingår i: Journal of Immunology. - : The American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 173:3, s. 1511-1513
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Tidskriftsartikel (refereegranskat)abstract
- We present evidence that nanotubular highways, or membrane nanotubes, facilitate a novel mechanism for intercellular communication in the immune system. Nanotubes were seen to connect multiple cells together and were readily formed between a variety of cell types, including human peripheral blood NK cells, macrophages, and EBV-transformed B cells. Nanotubes could be created upon disassembly of the immunological synapse, as cells move apart. Thus, nanotubular networks could be assembled from transient immunological synapses. Nanotubes were seen to contain GFP-tagged cell surface class I MHC protein expressed in one of the connected cells. Moreover, GPI-conjugated to GFP originating from one cell was transferred onto the surface of another at the connection with a nanotube. Thus, nanotubes can traffic cell surface proteins between immune cells over many tens of microns. Determining whether there are physiological functions for nanotubes if an intriguing new goal for cellular immunology.
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| 8. |
- Chantraine, Baptiste, et al.
(författare)
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Floer theory for Lagrangian cobordisms
- 2020
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Ingår i: Journal of differential geometry. - : INT PRESS BOSTON, INC. - 0022-040X .- 1945-743X. ; 114:3, s. 393-465
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Tidskriftsartikel (refereegranskat)abstract
- In this article we define intersection Floer homology for exact Lagrangian cobordisms between Legendrian submanifolds in the contactisation of a Liouville manifold, provided that the Chekanov-Eliashberg algebras of the negative ends of the cobordisms admit augmentations. From this theory we derive several long exact sequences relating the Morse homology of an exact Lagrangian cobordism with the bilinearised contact homologies of its ends. These are then used to investigate the topological properties of exact Lagrangian cobordisms.
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| 9. |
- Kozlov, Vladimir, et al.
(författare)
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On the Benjamin-Lighthill conjecture for water waves with vorticity
- 2017
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Ingår i: Journal of Fluid Mechanics. - : CAMBRIDGE UNIV PRESS. - 0022-1120 .- 1469-7645. ; 825, s. 961-1001
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Tidskriftsartikel (refereegranskat)abstract
- We consider the nonlinear problem of steady gravity-driven waves on the free surface of a two-dimensional flow of an inviscid, incompressible fluid (say, water). The water motion is supposed to be rotational with a Lipschitz continuous vorticity distribution, whereas the flow of finite depth is assumed to be unidirectional. We verify the Benjamin-Lighthill conjecture for flows with values of Bernoullis constant close to the critical one. For this purpose it is shown that a set of near-critical waves consists only of Stokes and solitary waves provided their slopes are bounded by a constant. Moreover, the subset of waves with crests located on a fixed vertical is uniquely parametrised by the flow force, which varies between its values for the supercritical and subcritical shear flows of constant depth. There exists another parametrisation for this set; it involves wave heights varying between the constant depth of the subcritical shear flow and the height of a solitary wave.
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| 10. |
- Longinetti, Elisa, et al.
(författare)
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Trajectories of cognitive processing speed and physical disability over 11 years following initiation of a first multiple sclerosis disease-modulating therapy
- 2024
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Ingår i: Journal of Neurology, Neurosurgery and Psychiatry. - : BMJ Publishing Group Ltd. - 0022-3050 .- 1468-330X. ; 95:2, s. 134-141
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: We analysed the COMparison Between All immunoTherapies for Multiple Sclerosis (NCT03193866), a Swedish nationwide observational study in relapsing-remitting multiple sclerosis (RRMS), to identify trajectories of processing speed and physical disability after disease-modulating therapy (DMT) start.METHODS: Using a group-modelling approach, we assessed trajectories of processing speed with oral Symbol Digit Modalities Test (SDMT) and physical disability with Expanded Disability Status Scale, from first DMT start among 1645 patients with RRMS followed during 2011-2022. We investigated predictors of trajectories using group membership as a multinomial outcome and calculated conditional probabilities linking membership across the trajectories.RESULTS: We identified 5 stable trajectories of processing speed: low SDMT scores (mean starting values=29.9; 5.4% of population), low/medium (44.3; 25.3%), medium (52.6; 37.9%), medium/high (63.1; 25.8%) and high (72.4; 5.6%). We identified 3 physical disability trajectories: no disability/stable (0.8; 26.8%), minimal disability/stable (1.6; 58.1%) and moderate disability (3.2; 15.1%), which increased to severe disability. Older patients starting interferons were more likely than younger patients starting rituximab to be on low processing speed trajectories. Older patients starting teriflunomide, with more than one comorbidity, and a history of pain treatment were more likely to belong to the moderate/severe physical disability trajectory, relative to the no disability one. There was a strong association between processing speed and physical disability trajectories.CONCLUSIONS: In this cohort of actively treated RRMS, patients' processing speed remained stable over the years following DMT start, whereas patients with moderate physical disability deteriorated in physical function. Nevertheless, there was a strong link between processing speed and disability after DMT start.
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