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Journal articles on the topic 'Migratory divide'

Author: Grafiati

Published: 4 June 2021

Last updated: 14 February 2022

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1

Toews, David P. L., Kira E. Delmore, Matthew M. Osmond, Philip D. Taylor, and Darren E. Irwin. "Migratory orientation in a narrow avian hybrid zone." PeerJ 5 (April 18, 2017): e3201. http://dx.doi.org/10.7717/peerj.3201.

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Background Zones of contact between closely related taxa with divergent migratory routes, termed migratory divides, have been suggested as areas where hybrid offspring may have intermediate and inferior migratory routes, resulting in low fitness of hybrids and thereby promoting speciation. In the Rocky Mountains of Canada there is a narrow hybrid zone between Audubon’s and myrtle warblers that is likely maintained by selection against hybrids. Band recoveries and isotopic studies indicate that this hybrid zone broadly corresponds to the location of a possible migratory divide, with Audubon’s warblers migrating south-southwest and myrtle warblers migrating southeast. We tested a key prediction of the migratory divide hypothesis: that genetic background would be predictive of migratory orientation among warblers in the center of the hybrid zone. Methods We recorded fall migratory orientation of wild-caught migrating warblers in the center of the hybrid zone as measured by video-based monitoring of migratory restlessness in circular orientation chambers. We then tested whether there was a relationship between migratory orientation and genetic background, as measured using a set of species-specific diagnostic genetic markers. Results We did not detect a significant association between orientation and genetic background. There was large variation among individuals in orientation direction. Mean orientation was towards the NE, surprising for birds on fall migration, but aligned with the mountain valley in which the study took place. Conclusions Only one other study has directly analyzed migratory orientation among naturally-produced hybrids in a migratory divide. While the other study showed an association between genetic background and orientation, we did not observe such an association in yellow-rumped warblers. We discuss possible reasons, including the possibility of a lack of a strong migratory divide in this hybrid zone and/or methodological limitations that may have prevented accurate measurements of long-distance migratory orientation.

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2

IRWIN, DARREN E. "Incipient ring speciation revealed by a migratory divide." Molecular Ecology 18, no. 14 (2009): 2923–25. http://dx.doi.org/10.1111/j.1365-294x.2009.04211.x.

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3

Battey, C. J., Ethan B. Linck, Kevin L. Epperly, et al. "A Migratory Divide in the Painted Bunting (Passerina ciris)." American Naturalist 191, no. 2 (2018): 259–68. http://dx.doi.org/10.1086/695439.

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4

Delmore, Kira E., and Darren E. Irwin. "Hybrid songbirds employ intermediate routes in a migratory divide." Ecology Letters 17, no. 10 (2014): 1211–18. http://dx.doi.org/10.1111/ele.12326.

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5

Delmore, Kira E., James W. Fox, and Darren E. Irwin. "Dramatic intraspecific differences in migratory routes, stopover sites and wintering areas, revealed using light-level geolocators." Proceedings of the Royal Society B: Biological Sciences 279, no. 1747 (2012): 4582–89. http://dx.doi.org/10.1098/rspb.2012.1229.

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Migratory divides are contact zones between breeding populations that use divergent migratory routes and have been described in a variety of species. These divides are of major importance to evolution, ecology and conservation but have been identified using limited band recovery data and/or indirect methods. Data from band recoveries and mitochondrial haplotypes suggested that inland and coastal Swainson's thrushes ( Catharus ustulatus ) form a migratory divide in western North America. We attached light-level geolocators to birds at the edges of this contact zone to provide, to our knowledge, the first direct test of a putative divide using data from individual birds over the entire annual cycle. Coastal thrushes migrated along the west coast to Mexico, Guatemala and Honduras. Some of these birds used multiple wintering sites. Inland thrushes migrated across the Rocky Mountains, through central North America to Columbia and Venezuela. These birds migrated longer distances than coastal birds and performed a loop migration, navigating over the Gulf of Mexico in autumn and around this barrier in spring. These findings support the suggestion that divergent migratory behaviour could contribute to reproductive isolation between migrants, advance our understanding of their non-breeding ecology, and are integral to development of detailed conservation strategies for this group.

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6

von Rönn, Jan A. C., Aaron B. A. Shafer, and Jochen B. W. Wolf. "Disruptive selection without genome-wide evolution across a migratory divide." Molecular Ecology 25, no. 11 (2016): 2529–41. http://dx.doi.org/10.1111/mec.13521.

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7

Alvarado, Allison H., Trevon L. Fuller, and Thomas B. Smith. "Integrative tracking methods elucidate the evolutionary dynamics of a migratory divide." Ecology and Evolution 4, no. 17 (2014): 3456–69. http://dx.doi.org/10.1002/ece3.1205.

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8

Rolshausen, Gregor, Keith A. Hobson, and H. Martin Schaefer. "Spring arrival along a migratory divide of sympatric blackcaps (Sylvia atricapilla)." Oecologia 162, no. 1 (2009): 175–83. http://dx.doi.org/10.1007/s00442-009-1445-3.

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9

Delmore, Kira E., Haley L. Kenyon, Ryan R. Germain, and Darren E. Irwin. "Phenotypic divergence during speciation is inversely associated with differences in seasonal migration." Proceedings of the Royal Society B: Biological Sciences 282, no. 1819 (2015): 20151921. http://dx.doi.org/10.1098/rspb.2015.1921.

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Differences in seasonal migration might promote reproductive isolation and differentiation by causing populations in migratory divides to arrive on the breeding grounds at different times and/or produce hybrids that take inferior migratory routes. We examined this question by quantifying divergence in song, colour, and morphology between sister pairs of North American migratory birds. We predicted that apparent rates of phenotypic differentiation would differ between pairs that do and do not form migratory divides. Consistent with this prediction, results from mixed effects models and Ornstein–Uhlenbeck models of evolution showed different rates of divergence between these groups; surprisingly, differentiation was greater among non-divide pairs. We interpret this finding as a result of variable rates of population blending and fusion between partially diverged forms. Ancient pairs of populations that subsequently fused are now observed as a single form, whereas those that did not fuse are observable as pairs and included in our study. We propose that fusion of two populations is more likely to occur when they have similar migratory routes and little other phenotypic differentiation that would cause reproductive isolation. By contrast, pairs with migratory divides are more likely to remain reproductively isolated, even when differing little in other phenotypic traits. These findings suggest that migratory differences may be one among several isolating barriers that prevent divergent populations from fusing and thereby increase the likelihood that they will continue differentiating as distinct species.

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10

Guillaumet, Alban, Brian Dorr, Guiming Wang, et al. "Determinants of local and migratory movements of Great Lakes double-crested cormorants." Behavioral Ecology 22, no. 5 (2011): 1096–103. http://dx.doi.org/10.1093/beheco/arr096.

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Abstract We investigated how individual strategies combine with demographic and ecological factors to determine local and migratory movements in the double-crested cormorants (Phalacrocorax auritus). One hundred and forty-five cormorants were captured from 14 nesting colonies across the Great Lakes area and fitted with satellite transmitters. We first tested the hypotheses that sexual segregation, density-dependent effects, and the intensity of management operations influenced home range size during the breeding season. The influence of these factors appeared to be limited in part due to random variability in foraging and dispersal decisions at individual and colony levels. We also designed a statistical framework to investigate the degree and determinants of migratory connectivity. Our analyses revealed a significant migratory connectivity in cormorants, although we also observed a nonnegligible amount of individual variability and flexibility. Our data were most consistent with the existence of a migratory divide across the Great Lakes, with western populations using mainly the Mississippi Flyway and eastern populations the Atlantic Flyway. Previous and current studies suggest that the divide cannot be explained by past divergence in isolation, a way to diminish travel cost, or the Appalachians constituting an ecological barrier per se but is rather the consequence of the distribution of suitable stopover and nonbreeding areas. However, a parallel migration system and no migratory divide could not be entirely ruled out with present data.

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11

SANTIAGO-ALARCON, D., R. BLOCH, G. ROLSHAUSEN, H. M. SCHAEFER, and G. SEGELBACHER. "Prevalence, diversity, and interaction patterns of avian haemosporidians in a four-year study of blackcaps in a migratory divide." Parasitology 138, no. 7 (2011): 824–35. http://dx.doi.org/10.1017/s0031182011000515.

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SUMMARYMigratory birds contribute to the movement of avian parasites between distant locations, thereby influencing parasite distribution and ecology. Here we analyse the prevalence, diversity and interaction patterns of Haemosporida parasites infecting Blackcap (Sylvia atricapilla) populations in a recently established migratory divide of southwestern Germany across 4 years. We hypothesize that the temporal and spatial isolation provided by 2 sympatric Blackcap breeding populations (migratory divide) might modify ecological interactions and thus create differences in the structure of the parasite community according to migratory route. We used a fragment of the mitochondrial DNA cytochromebgene to determine haemosporidian haplotypes. We detected an overall infection prevalence of 70·3% (348 out of 495 blackcaps sampled from 2006 to 2009), and prevalence rates were significantly different among years and seasons. We observed a total of 27 parasite haplotypes infecting blackcaps, from them 6 new rareHaemoproteushaplotypes were found in 2 mixed infections.H. parabelopolskyihaplotypes SYAT01 (35·7%) and SYAT02 (20·8%) comprised most of the infections. An association analysis suggests that SYAT01 and SYAT02 are interacting negatively, implying that they are either competing directly for host resources, or indirectly by eliciting a cross-immune response. Molecular data show no clear difference between the parasite communities infecting blackcaps with different migratory routes, despite some temporal and spatial isolation between the two sympatric blackcap populations.

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12

Bearhop, S. "Assortative Mating as a Mechanism for Rapid Evolution of a Migratory Divide." Science 310, no. 5747 (2005): 502–4. http://dx.doi.org/10.1126/science.1115661.

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13

Bensch, Staffan, Tord Andersson, and Susanne Akesson. "Morphological and Molecular Variation across a Migratory Divide in Willow Warblers, Phylloscopus trochilus." Evolution 53, no. 6 (1999): 1925. http://dx.doi.org/10.2307/2640451.

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14

Bensch, Staffan, Tord Andersson, and Susanne Åkesson. "MORPHOLOGICAL AND MOLECULAR VARIATION ACROSS A MIGRATORY DIVIDE IN WILLOW WARBLERS,PHYLLOSCOPUS TROCHILUS." Evolution 53, no. 6 (1999): 1925–35. http://dx.doi.org/10.1111/j.1558-5646.1999.tb04573.x.

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15

Bobek, Miroslav, Radek Hampl, Lubomír Peške, František Pojer, Jaroslav Šimek, and Stanislav Bureš. "African Odyssey project - satellite tracking of black storksCiconia nigrabreeding at a migratory divide." Journal of Avian Biology 39, no. 5 (2008): 500–506. http://dx.doi.org/10.1111/j.0908-8857.2008.04285.x.

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16

Hobson, Keith A., Kevin J. Kardynal, Steven L. Van Wilgenburg, et al. "A Continent-Wide Migratory Divide in North American Breeding Barn Swallows (Hirundo rustica)." PLOS ONE 10, no. 6 (2015): e0129340. http://dx.doi.org/10.1371/journal.pone.0129340.

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17

Rolshausen, Gregor, Gernot Segelbacher, Keith A. Hobson, and H. Martin Schaefer. "Contemporary Evolution of Reproductive Isolation and Phenotypic Divergence in Sympatry along a Migratory Divide." Current Biology 19, no. 24 (2009): 2097–101. http://dx.doi.org/10.1016/j.cub.2009.10.061.

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18

Hobson, Keith A., Kevin J. Kardynal, Steven L. Van Wilgenburg, et al. "Correction: A Continent-Wide Migratory Divide in North American Breeding Barn Swallows (Hirundo rustica)." PLOS ONE 10, no. 7 (2015): e0133104. http://dx.doi.org/10.1371/journal.pone.0133104.

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19

Ruegg, Kristen. "GENETIC, MORPHOLOGICAL, AND ECOLOGICAL CHARACTERIZATION OF A HYBRID ZONE THAT SPANS A MIGRATORY DIVIDE." Evolution 62, no. 2 (2008): 452–66. http://dx.doi.org/10.1111/j.1558-5646.2007.00263.x.

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20

Hermes, Claudia, Raeann Mettler, Diego Santiago-Alarcon, Gernot Segelbacher, and H. Martin Schaefer. "Spatial Isolation and Temporal Variation in Fitness and Condition Facilitate Divergence in a Migratory Divide." PLOS ONE 10, no. 12 (2015): e0144264. http://dx.doi.org/10.1371/journal.pone.0144264.

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21

Delmore, Kira E., Benjamin M. Van Doren, Greg J. Conway, et al. "Individual variability and versatility in an eco-evolutionary model of avian migration." Proceedings of the Royal Society B: Biological Sciences 287, no. 1938 (2020): 20201339. http://dx.doi.org/10.1098/rspb.2020.1339.

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Seasonal migration is a complex and variable behaviour with the potential to promote reproductive isolation. In Eurasian blackcaps ( Sylvia atricapilla ), a migratory divide in central Europe separating populations with southwest (SW) and southeast (SE) autumn routes may facilitate isolation, and individuals using new wintering areas in Britain show divergence from Mediterranean winterers. We tracked 100 blackcaps in the wild to characterize these strategies. Blackcaps to the west and east of the divide used predominantly SW and SE directions, respectively, but close to the contact zone many individuals took intermediate (S) routes. At 14.0° E, we documented a sharp transition from SW to SE migratory directions across only 27 (10–86) km, implying a strong selection gradient across the divide. Blackcaps wintering in Britain took northwesterly migration routes from continental European breeding grounds. They originated from a surprisingly extensive area, spanning 2000 km of the breeding range. British winterers bred in sympatry with SW-bound migrants but arrived 9.8 days earlier on the breeding grounds, suggesting some potential for assortative mating by timing. Overall, our data reveal complex variation in songbird migration and suggest that selection can maintain variation in migration direction across short distances while enabling the spread of a novel strategy across a wide range.

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22

Helbig, A. "Genetic basis, mode of inheritance and evolutionary changes of migratory directions in palaearctic warblers (Aves: Sylviidae)." Journal of Experimental Biology 199, no. 1 (1996): 49–55. http://dx.doi.org/10.1242/jeb.199.1.49.

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The genetic basis, mode of inheritance and recent evolutionary changes of migratory directions in birds are discussed on the basis of published and new experimental evidence. Displacement experiments with wild-caught migrants and orientation tests with hand-reared passerines illustrate that inexperienced young birds possess genetic information about the direction and approximate distance of migration, but not about the geographic location of the winter quarters. Hand-raised blackcaps Sylvia atricapilla from east and west of the Central European migratory divide, when tested under identical conditions, exibited population-specific migratory directions in orientation cages. Cross-breeding of birds from these two populations demonstrated an intermediate mode of inheritance of this behavioural character. New data on the orientation of an F2 generation suggest that the directional information is encoded by only a few major genes. Migratory adaptations may have evolved recently, in some cases rapidly, as is illustrated by the establishment of a new migration route of central European blackcaps to winter quarters in the British Isles. This new route is shown (in a captive breeding experiment) to be based on a novel, genetically programmed westnorthwesterly migratory direction. It must have spread from almost zero to 7-11 % frequency in parts of central Europe within only three decades. The novel direction is also inherited phenotypically intermediately; its rapid evolution may be mediated by assortative mating based on differential arrival times at the breeding grounds. The evolutionary flexibility of migratory adaptations is discussed in relation to changes in the environment, both natural and accelerated by man.

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23

Ruegg, K., E. C. Anderson, and H. Slabbekoorn. "Differences in timing of migration and response to sexual signalling drive asymmetric hybridization across a migratory divide." Journal of Evolutionary Biology 25, no. 9 (2012): 1741–50. http://dx.doi.org/10.1111/j.1420-9101.2012.02554.x.

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24

Terraube, J., F. Mougeot, T. Cornulier, A. Verma, A. Gavrilov, and B. Arroyo. "Broad wintering range and intercontinental migratory divide within a core population of the near-threatened pallid harrier." Diversity and Distributions 18, no. 4 (2011): 401–9. http://dx.doi.org/10.1111/j.1472-4642.2011.00830.x.

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25

Svensson, L. M. E., K. C. Ruegg, C. H. Sekercioglu, and R. N. M. Sehgal. "WIDESPREAD AND STRUCTURED DISTRIBUTIONS OF BLOOD PARASITE HAPLOTYPES ACROSS A MIGRATORY DIVIDE OF THE SWAINSON'S THRUSH (CATHARUS USTULATUS)." Journal of Parasitology 93, no. 6 (2007): 1488–95. http://dx.doi.org/10.1645/ge-1064.1.

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26

Bensch, Staffan, Susanne Åkesson, and Darren E. Irwin. "The use of AFLP to find an informative SNP: genetic differences across a migratory divide in willow warblers." Molecular Ecology 11, no. 11 (2008): 2359–66. http://dx.doi.org/10.1046/j.1365-294x.2002.01629.x.

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27

Procházka, Petr, Steven L. Van Wilgenburg, Júlio M. Neto, Reuven Yosef та Keith A. Hobson. "Using stable hydrogen isotopes (δ2H) and ring recoveries to trace natal origins in a Eurasian passerine with a migratory divide". Journal of Avian Biology 44, № 6 (2013): 541–50. http://dx.doi.org/10.1111/j.1600-048x.2013.00185.x.

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28

Delmore, Kira E., Sariel Hübner, Nolan C. Kane, et al. "Genomic analysis of a migratory divide reveals candidate genes for migration and implicates selective sweeps in generating islands of differentiation." Molecular Ecology 24, no. 8 (2015): 1873–88. http://dx.doi.org/10.1111/mec.13150.

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29

Dallimer, M., P. J. Jones, J. M. Pemberton, and R. A. Cheke. "Lack of genetic and plumage differentiation in the red-billed quelea Quelea quelea across a migratory divide in southern Africa." Molecular Ecology 12, no. 2 (2003): 345–53. http://dx.doi.org/10.1046/j.1365-294x.2003.01733.x.

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30

Procházka, Petr, Vojtěch Brlík, Elizabeth Yohannes, et al. "Across a migratory divide: divergent migration directions and non-breeding grounds of Eurasian reed warblers revealed by geolocators and stable isotopes." Journal of Avian Biology 49, no. 6 (2018): jav—012516. http://dx.doi.org/10.1111/jav.01769.

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31

Chamberlain, C. P., S. Bensch, X. Feng, S. Åkesson, and T. Andersson. "Stable isotopes examined across a migratory divide in Scandinavian willow warblers ( Phylloscopus trochilus trochilus and Phylloscopus trochilus acredula ) reflect their African winter quarters." Proceedings of the Royal Society of London. Series B: Biological Sciences 267, no. 1438 (2000): 43–48. http://dx.doi.org/10.1098/rspb.2000.0964.

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32

Lee, Christina Y., and Victoria L. Bautch. "Ups and Downs of Guided Vessel Sprouting: The Role of Polarity." Physiology 26, no. 5 (2011): 326–33. http://dx.doi.org/10.1152/physiol.00018.2011.

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Blood vessel networks expand to meet oxygen demands via sprouting angiogenesis. This process is heterogeneous but not random; as sprouts form and extend, neighboring endothelial cells do not sprout but divide. Sprouting is regulated by local sprout guidance cues produced by the vessels themselves, as well as extrinsic cues. Endothelial cells in developing vessels orient in several axes to establish migratory polarity, apical-basolateral polarity, and planar cell polarity. Although little is known about how polarity axes are set up or maintained, they are important for vessel formation and function. This review focuses on the current knowledge of how blood vessel sprouting is regulated and guided, the role of endothelial cell polarity in forming vessels, and how these processes affect vessel function and are potentially perturbed in pathologies with vascular components.

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33

Braun, Lorraine, Al B. Ewen, and Cedric Gillott. "THE LIFE CYCLE AND ULTRASTRUCTURE OF MALAMEBA LOCUSTAE (KING AND TAYLOR) (AMOEBIDAE) IN THE MIGRATORY GRASSHOPPER MELANOPLUS SANGUINIPES (F.) (ACRIDIDAE),." Canadian Entomologist 120, no. 8-9 (1988): 759–72. http://dx.doi.org/10.4039/ent120759-8.

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AbstractThe life history and ultrastructure of the protozoan Malameba locustae (King and Taylor) were studied in the migratory grasshopper Melanoplus sanguinipes (F.) using feeding and injection studies. Insects fed cysts developed infection in the Malpighian tubules 5–6 days later; no trophozoites were observed in haemolymph samples taken 2–20 days post-feeding. After excystment, a few trophozoites entered the midgut epithelium and many were located near the basement membrane of the epithelial cells, where they appeared to degenerate. Trophozoites were not seen to divide in the midgut epithelium, and apparently did not damage this tissue. Trophozoites injected directly into the haemocoel could not be recovered even 4 h after injection, and the Malpighian tubules did not become infected. It was concluded that trophozoites did not penetrate the midgut to enter the haemocoel or move through the haemocoel to infect the Malpighian tubules, but instead probably entered the tubules directly from the gut. Trophozoite ultrastructure in midgut and Malpighian tubules, and cyst wall deposition were described.

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34

Hager, G., and C. N. David. "Pattern of differentiated nerve cells in hydra is determined by precursor migration." Development 124, no. 2 (1997): 569–76. http://dx.doi.org/10.1242/dev.124.2.569.

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The nervous system of the fresh water polyp hydra is built up as a nerve net spread over the whole body, with higher densities in the head and the foot. In adult hydra, as a result of continuous growth, new nerve cell differentiation takes place continuously. The pattern of nerve cell differentiation and the role of nerve cell precursor migration in establishing the pattern have been observed in vivo by vitally labelling precursor cells with DiI. The results indicate that nerve cell precursors arise directly from stem cells, complete a final cell cycle and divide, giving rise to two daughter cells, which differentiate into nerve cells. A subpopulation of the nerve cell precursors are migratory for a brief interval at the onset of the terminal cell cycle, then complete the cell cycle and divide at the site of differentiation. Labelling small patches of tissue in the head, body column and peduncle/foot with DiI indicated that formation of nerve cell precursors was nearly constant at all three positions. However, at least half of the labelled precursors in the body column migrated to the head or foot before differentiating; by contrast, precursors in head and foot differentiated in situ without significant migration. This redistribution leads to a net increase of nerve cell precursors in head and foot compared to body column and thus to the higher density of nerve cells in these regions.

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35

Literák, Ivan, Petr Kafka, Josef Vrána, and František Pojer. "Migration of Black Storks Ciconia nigra at a migratory divide: two different routes used by siblings from one nest and two different routes used by one individual." Ringing & Migration 32, no. 1 (2017): 19–24. http://dx.doi.org/10.1080/03078698.2017.1332260.

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DE PINHO, JOÃO BATISTA, MÔNICA ARAGONA, KARLO YOSHIHIRO PIOTO HAKAMADA, and MIGUEL ÂNGELO MARINI. "Migration patterns and seasonal forest use by birds in the Brazilian Pantanal." Bird Conservation International 27, no. 3 (2017): 371–87. http://dx.doi.org/10.1017/s0959270916000290.

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SummaryThe use of forest habitats and migratory patterns are still unclear for tropical birds. Some are described herein for the Pantanal wetlands of Brazil. Thus, our aim was to describe different patterns of forest habitat use by birds and classify the birds’ migration patterns for the northern Pantanal region, Brazil. From September 1999 to December 2003, we sampled four forest types, during which we collected standardised data with mist-net captures and point counts, with additional ad lib. observations. We recorded 214 bird species: 113 (52.8%) were total habitat generalists; 41 (19.2%) were forest generalists; 19 (8.9%) were flooded habitat specialists; and 28 (13.1%) were not classified due to the low number of records; three other categories of habitat use divide the remaining 6% of records. About half of the species showed some migratory behaviour, these were classified by us according to the season they spent in the area: 121 species (56.5%) as residents, 28 (13.1%) as run-off and dry migrants, 11 (5.1%) as run-off (winter) migrants, eight (3.7%) as dry (breeding) migrants, eight (3.7%) as dry and flooding (summer) migrants, eight (3.7%) as flooding migrants, three (1.4%) as flooding and run-off migrants, and 27 (12.6%) as uncommon. We constructed community occupancy models with six of the eight patterns of migration described; flooding migrants and run-off migrants were not modelled since the few species recorded also had very few detections. As expected, the model confirmed that species from all six tested migration patterns arrive and depart from the Pantanal across the seasons. Contrary to most Neotropical forests, there was a high percentage (43.5%) of non-resident species. The results show the need of investing heavily in preserving different landscape units within the Pantanal, but also in the surrounding Cerrado region, in order to conserve resident and short distance intra-tropical migrants.

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Ben-Rafael, Eliezer, and Miriam Ben-Rafael. "Linguistic landscapes in an era of multiple globalizations." Linguistic Landscape. An international journal 1, no. 1-2 (2015): 19–37. http://dx.doi.org/10.1075/ll.1.1-2.02ben.

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This paper focuses on linguistic landscapes in present-day urban settings. These spaces consist of numberless establishments riddled with versatile texts or ‘LL items’. They are foci of both the development of globalization that conquers the world through commercial globe-encompassing networks, and of massive migrations from underprivileged countries to privileged ones. In each such city, one distinguishes major ‘downtowns’ and secondary ones in neighbourhoods, whose variety reflects a complex composition. LL investigations help understand how far and in what ways dissonant cleavages divide the public space. Chaos is the rule in this urban landscape, but where it illustrates some permanence and recurrence, it becomes familiar and the feeling of disorder may leave room for a notion of gestalt. Turning from here to the empirical investigation of LLs in Brussels, Berlin, and Tel-Aviv, we ask, as far as LLs can say: (1) if globalization causes the weakening of allegiances to all-societal symbols in favour of supra-national ones; (2) if migratory movements toward megapolises express themselves in the creation of segregated LLs or, on the contrary, indicate some ‘melting’ tendencies of the new populations into society’s mainstream; and (3) to what extent these questions elicit the same answers in different places or contribute to different configurations.

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38

Mauerhofer, Volker. "Activities of Environmental Convention-Secretariats: Laws, Functions and Discretions." Sustainability 11, no. 11 (2019): 3116. http://dx.doi.org/10.3390/su11113116.

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Multilateral Environmental Agreements—MEAs—are indispensable legal frameworks for environmental sustainability and also define the operating rules of their implementation bodies (“Secretariats”). The contribution assesses in how far the norms defining Secretariats’ functions differ and also reflect on actual functions for three MEAs, namely (1) the Convention on International Trade in Endangered Species of Wild Fauna and Flora-CITES (1973), (2) the Convention on Biological Diversity—CBD (1992), and (3) the Convention on Migratory Species—CMS (1979). It does so by comparative legal interpretation of the main norms of these MEAs laying down the functions of its respective Secretariats as well as an in-depth review of academic literature about these functions. The results for these three conventions divide into nine functional areas and show an unexpectedly wide range of different functions laid down in the conventions as well as extensive variety in the discretion for many of these functional areas. Some potential explanations of these formal differences are provided. The paper further finds that actually executed functions may not be fully covered by the underlying legal norms but rather by “flexible” highest governing bodies of MEAs and concludes that occasionally an unusual legislative style was chosen, and shows potential solutions and future research directions.

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Yu, Wei, Lucy E. O'Brien, Fei Wang, Henry Bourne, Keith E. Mostov, and Mirjam M. P. Zegers. "Hepatocyte Growth Factor Switches Orientation of Polarity and Mode of Movement during Morphogenesis of Multicellular Epithelial Structures." Molecular Biology of the Cell 14, no. 2 (2003): 748–63. http://dx.doi.org/10.1091/mbc.e02-06-0350.

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Epithelial cells form monolayers of polarized cells with apical and basolateral surfaces. Madin-Darby canine kidney epithelial cells transiently lose their apico-basolateral polarity and become motile by treatment with hepatocyte growth factor (HGF), which causes the monolayer to remodel into tubules. HGF induces cells to produce basolateral extensions. Cells then migrate out of the monolayer to produce chains of cells, which go on to form tubules. Herein, we have analyzed the molecular mechanisms underlying the production of extensions and chains. We find that cells switch from an apico-basolateral polarization in the extension stage to a migratory cell polarization when in chains. Extension formation requires phosphatidyl-inositol 3-kinase activity, whereas Rho kinase controls their number and length. Microtubule dynamics and cell division are required for the formation of chains, but not for extension formation. Cells in the monolayer divide with their spindle axis parallel to the monolayer. HGF causes the spindle axis to undergo a variable “seesaw” motion, so that a daughter cells can apparently leave the monolayer to initiate a chain. Our results demonstrate the power of direct observation in investigating how individual cell behaviors, such as polarization, movement, and division are coordinated in the very complex process of producing multicellular structures.

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Gow, Elizabeth A., and Karen L. Wiebe. "Males migrate farther than females in a differential migrant: an examination of the fasting endurance hypothesis." Royal Society Open Science 1, no. 4 (2014): 140346. http://dx.doi.org/10.1098/rsos.140346.

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Patterns of migration including connectivity between breeding and non-breeding populations and intraspecific variation in the distance travelled are important to study because they can affect individual fitness and population dynamics. Using data from 182 band recoveries across North America and 17 light-level geolocators, we examined the migration patterns of the northern flicker ( Colaptes auratus ), a migratory woodpecker. This species is unusual among birds because males invest more in parental care than females. Breeding latitude was positively correlated to migration distance because populations in the north appeared to travel farther distances than southern populations to find wintering locations with little snow cover. Connectivity was strong for populations west and east of the Continental Divide. Contrary to the three main hypotheses for intraspecific variation in migration distance, females wintered, on average, farther north than males, although there was overlap throughout their non-breeding range. This pattern contradicts those of other species found to date and is most consistent with the fasting endurance hypothesis if investment in parental care depletes the energy reserves of male flickers more than females. We thus propose a new factor, parental effort, which may influence optimal wintering areas and migration strategies within birds, and encourage future experimental studies to test the relationship between parental care roles and migration strategies of the sexes.

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Langewiesche, Renate, and Martina Lubyova. "Migration, mobility and the free movement of persons: an issue for current and future EU members." Transfer: European Review of Labour and Research 6, no. 3 (2000): 450–67. http://dx.doi.org/10.1177/102425890000600309.

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This article, in addition to providing information on and discussing lines of argumentation and probable developments, proposes an 'integrated' approach to the issue of migration. Public debate in some of the European Union (EU) member countries gives the impression of a deep East-West divide as far as migration movements are concerned. It is often feared that opening the EU towards the East will, by way of the expected migratory flows and low-wage competition, result in massive distortions on west European labour markets, accompanied by job losses and pressure on wages. Policy-makers and the public at large in applicant countries in Central and Eastern Europe (CEECs) resent calls in some EU Member States for transitional periods for the free movement of persons, excluding the freedom of the new member's citizens to move in the enlarged Single Market. We hold that it is too short-sighted to look at the two sides merely as 'antagonists': First, a look at current data and projections about future developments should be conducive to dispel the diffuse fears in the current EU of being inundated by east European labour migrants once these countries accede. Secondly, flanking policy instruments, such as structural and regional policies, the fostering of social partnership in the CEECs and the introduction of active labour market strategies, all of which are still more or less in a stage of infancy, as well as close cooperation in Justice and Home Affairs will have to play their full role before and after accession, in order to mitigate possible negative effects in certain segments of the labour market. This paper also gives some insights into labour migration and the effects of the application of EU border control requirements in a number of accession countries, an aspect greatly overlooked in debates within the current EU

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Copenhaver, P. F. "Origins, migration and differentiation of glial cells in the insect enteric nervous system from a discrete set of glial precursors." Development 117, no. 1 (1993): 59–74. http://dx.doi.org/10.1242/dev.117.1.59.

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The enteric nervous system (ENS) of the moth, Manduca sexta, consists of two primary cellular domains and their associated nerves. The neurons of the anterior domain occupy two small peripheral ganglia (the frontal and hypocerebral ganglia), while a second population of neurons occupies a branching nerve plexus (the enteric plexus) that spans the foregut-midgut boundary. Previously, we have shown these two regions arise by separate programs of neurogenesis: cells that form the anterior enteric ganglia are generated from three discrete proliferative zones that differentiate within the foregut epithelium. In contrast, the cells of the enteric plexus (the EP cells) emerge from a neurogenic placode within the posterior lip of the foregut. Both sets of neurons subsequently undergo an extended period of migration and reorganization to achieve their mature distributions. We now show that prior to the completion of neurogenesis, an additional class of precursor cells is generated from the three proliferative zones of the foregut. Coincident with the onset of neuronal migration, this precursor class enters a phase of enhanced mitotic activity, giving rise to a population of cells that continue to divide as the ENS matures. Using clonal analyses of individual precursors, we demonstrate that the progeny of these cells become distributed along the same pathways taken by the migratory neurons; subsequently, they contribute to an ensheathing layer around the branches of the enteric plexus and the enteric ganglia. We conclude that this additional precursor class, which shares a common developmental origin with the enteric neurons, gives rise to a distinct population of peripheral glial cells. Moreover, the distribution of enteric glial cells is achieved by their migration and differentiation along the same pathways that are formed during the preceding phases of neuronal migration.

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Højrup, P., S. O. Andersen, and P. Roepstorff. "Primary structure of a structural protein from the cuticle of the migratory locust, Locusta migratoria." Biochemical Journal 236, no. 3 (1986): 713–20. http://dx.doi.org/10.1042/bj2360713.

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The complete amino acid sequence of a structural protein isolated from pharate cuticle of the locust Locusta migratoria was determined. The protein has an unusual amino acid composition: 42% of the residues are alanine and only 14 of the 20 common amino acid residues are present. The primary structure consists of regions enriched in particular amino acid residues. The N-terminal region and a region close to the C-terminus are enriched in glycine. The rest of the protein is dominated by alanine, except for two short regions enriched in hydrophilic residues. Almost all the proline residues are situated in the alanine-rich regions in a conserved sequence ‘A-A-P-A/V’. An internal duplication has taken place covering most of the protein except for the glycine-rich regions. Owing to the unusual features of the protein a combination of automated Edman degradations and plasma-desorption m.s. was used to determine the complete sequence. The protein does not show sequence homology to other proteins, but proteins divided into regions enriched in the same kind of amino acid residues have been isolated from other insect structures.

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MØLLER, A. P., L. Z. GARAMSZEGI, J. M. PERALTA-SÁNCHEZ, and J. J. SOLER. "Migratory divides and their consequences for dispersal, population size and parasite-host interactions." Journal of Evolutionary Biology 24, no. 8 (2011): 1744–55. http://dx.doi.org/10.1111/j.1420-9101.2011.02302.x.

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Scordato, Elizabeth S. C., Chris C. R. Smith, Georgy A. Semenov, et al. "Migratory divides coincide with reproductive barriers across replicated avian hybrid zones above the Tibetan Plateau." Ecology Letters 23, no. 2 (2019): 231–41. http://dx.doi.org/10.1111/ele.13420.

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Handerson Joseph. "The haitian migratory system in the guianas: beyond borders." Diálogos 24, no. 2 (2020): 198–258. http://dx.doi.org/10.4025/dialogos.v24i2.54154.

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The Guianas are an important migratory field in the Caribbean migratory system, whereby goods, objects, currencies, and populations circulate for different reasons: geographical, cultural proximity, climatic, geopolitical and socioeconomic factors. From the 1960s and 1970s, Haitian migration increased in the Guianas. Five decades later, after the January 2010 earthquake, the migratory spaces were intensified in the region, Brazil became part of them as a country of residence and transit to reach French Guiana and Suriname. In 2013, the routes were altered. Some migrants started to use the Republic of Guyana to enter Brazil through the border with Roraima, in the Amazon, or to cross the border towards Suriname and French Guiana. This article is divided into two levels. First, it describes the way in which migrants' practices and trajectories intersect national borders in the Guianas. Then, it analyzes the migratory system, documents and papers, and the problems that the different Haitian migratory generations raise in space and time. The ethnographic research is based on the Triple Border Brazil, Colombia and Peru, but also in Suriname, French Guiana and Haiti.

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Moens, Maurice, and Yunliang Peng. "Host resistance and tolerance to migratory plant-parasitic nematodes." Nematology 5, no. 2 (2003): 145–77. http://dx.doi.org/10.1163/156854103767139653.

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AbstractPlant-parasitic nematodes are divided according to their feeding strategy into three major groups: sedentary endoparasites, migratory endoparasites and ectoparasites. Compared to what is known about sedentary endoparasitic nematode species, resistant and tolerant relationships between the nematodes from the latter two groups and their hosts are much less documented. However, methods for screening and evaluation of the resistance and tolerance of plants to migratory plant-parasitic nematodes have been well developed and sources of resistance and tolerance to these nematodes have been found. Advances have been made in breeding resistance to migratory plant-parasitic nematodes in rice, alfalfa, banana, pine trees, grape, woody fruits and other crops. Although accessions immune to stem, leaf and bud nematodes are found quite frequently, host resistance to migratory root-parasitic nematodes has been detected less frequently and generally only partly reduces nematode multiplication. Host tolerance to migratory nematodes is important even for resistant varieties and therefore is gaining attention. An insufficient degree of resistance and tolerance, their variability with the environment, and their linkage to undesired agricultural or horticultural characters are commonly observed. Polygenic bases for plant resistance and tolerance to migratory nematodes have been demonstrated by genetic and biochemical observations and make breeding even more complicated than that for resistance to sedentary plant-parasitic nematodes. These factors, with the presence of different nematode species in the field and community and population differences in pathogenicity, hinder the availability of host resistance and tolerance and offer a big challenge.

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Pustovalova, Margarita, Lina Alhaddad, Taisia Blokhina, et al. "The CD44high Subpopulation of Multifraction Irradiation-Surviving NSCLC Cells Exhibits Partial EMT-Program Activation and DNA Damage Response Depending on Their p53 Status." International Journal of Molecular Sciences 22, no. 5 (2021): 2369. http://dx.doi.org/10.3390/ijms22052369.

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Ionizing radiation (IR) is used for patients diagnosed with unresectable non-small cell lung cancer (NSCLC). However, radiotherapy remains largely palliative due to the survival of specific cell subpopulations. In the present study, the sublines of NSCLC cells, A549IR (p53wt) and H1299IR (p53null) survived multifraction X-ray radiation exposure (MFR) at a total dose of 60 Gy were investigated three weeks after the MFR course. We compared radiosensitivity (colony formation), expression of epithelial-mesenchymal transition (EMT) markers, migration activity, autophagy, and HR-dependent DNA double-strand break (DSB) repair in the bulk and entire CD44high/CD166high CSC-like populations of both parental and MFR survived NSCLC cells. We demonstrated that the p53 status affected: the pattern of expression of N-cadherin, E-cadherin, Vimentin, witnessing the appearance of EMT-like phenotype of MFR-surviving sublines; 1D confined migratory behavior (wound healing); the capability of an irradiated cell to continue to divide and form a colony of NSCLC cells before and after MFR; influencing the CD44/CD166 expression level in MFR-surviving NSCLC cells after additional single irradiation. Our data further emphasize the impact of p53 status on the decay of γH2AX foci and the associated efficacy of the DSB repair in NSCLC cells survived after MFR. We revealed that Rad51 protein might play a principal role in MFR-surviving of p53 null NSCLC cells promoting DNA DSB repair by homologous recombination (HR) pathway. The proportion of Rad51 + cells elevated in CD44high/CD166high population in MFR-surviving p53wt and p53null sublines and their parental cells. The p53wt ensures DNA-PK-mediated DSB repair for both parental and MFR-surviving cells irrespectively of a subsequent additional single irradiation. Whereas in the absence of p53, a dose-dependent increase of DNA-PK-mediated non-homologous end joining (NHEJ) occurred as an early post-irradiation response is more intensive in the CSC-like population MFR-surviving H1299IR, compared to their parental H1299 cells. Our study strictly observed a significantly higher content of LC3 + cells in the CD44high/CD166high populations of p53wt MFR-surviving cells, which enriched the CSC-like cells in contrast to their p53null counterparts. The additional 2 Gy and 5 Gy X-ray exposure leads to the dose-dependent increase in the proportion of LC3 + cells in CD44high/CD166high population of both parental p53wt and p53null, but not MFR-surviving NSCLC sublines. Our data indicated that autophagy is not necessarily associated with CSC-like cells’ radiosensitivity, emphasizing that careful assessment of other milestone processes (such as senescence and autophagy-p53-Zeb1 axis) of primary radiation responses may provide new potential targets modulated for therapeutic benefit through radiosensitizing cancer cells while rescuing normal tissue. Our findings also shed light on the intricate crosstalk between autophagy and the p53-related EMT, by which MFR-surviving cells might obtain an invasive phenotype and metastatic potential.

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Segura, Elodie, Jenny Valladeau-Guilemond, Marie-Hélène Donnadieu, Xavier Sastre-Garau, Vassili Soumelis, and Sebastian Amigorena. "Characterization of resident and migratory dendritic cells in human lymph nodes." Journal of Experimental Medicine 209, no. 4 (2012): 653–60. http://dx.doi.org/10.1084/jem.20111457.

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Dendritic cells (DCs) initiate adaptive immune responses in lymph nodes (LNs). In mice, LN DCs can be divided into resident and tissue-derived populations, the latter of which migrate from the peripheral tissues. In humans, different subsets of DCs have been identified in the blood, spleen, and skin, but less is known about populations of resident and migratory tissue-derived DCs in LNs. We have analyzed DCs in human LNs and identified two populations of resident DCs that are present in all LNs analyzed, as well as in the spleen and tonsil, and correspond to the two known blood DC subtypes. We also identify three main populations of skin-derived migratory DCs that are present only in skin-draining LNs and correspond to the DC subsets found in the skin. Resident DCs subsets induce both Th1 and Th2 cytokines in naive allogeneic T lymphocytes, whereas the corresponding blood subsets failed to induce efficient Th2 polarization. LN-resident DCs also cross-present antigen without in vitro activation, whereas blood DCs fail to do so. Among migratory DCs, one subset was poor at both CD4+ and CD8+ T cell activation, whereas the other subsets induced only Th2 polarization. We conclude that in humans, skin-draining LNs host both resident and migratory DC subsets with distinct functional abilities.

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Stöcker-Segre, Sabine, and Daniel Weihs. "Impact of Environmental Changes on Migratory Bird Survival." International Journal of Ecology 2014 (2014): 1–15. http://dx.doi.org/10.1155/2014/245849.

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We present a mathematical model that studies and simulates the interconnection between energetic and ecological aspects of bird migration. By comparing model predictions with experimental data, we show that it can be used to assess the impact of changing environmental conditions in breeding, wintering, and stop-over sites on migratory success. We relate in particular to the European white stork (Ciconia ciconia) and its Eastern migration route and discuss questions concerning the timing, stopover, and feeding behavior en route. Opinions concerning the importance of resource availability and resource quality en route are divided. Whereas some studies have shown that storks gain weight in the wintering site, but almost do not feed en route, others stress the importance of the quality of stop-over locations. We address these questions and simulate the development of stork populations for changing environmental conditions. We demonstrate that resource availability and competition for breeding sites are crucial factors determining the timing of spring migration and the length of stop-over periods. Analyzing the robustness of migration strategies with respect to changing environmental conditions, we show that birds will shorten their stay in stop-over places of poor resource availability rather than prolonging it in the attempt to gain time for accumulating fat reserves.

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