scholarly journals South east villages in the province of Buenos Aires, an approach to the study of its population dynamics

Huellas ◽  
2019 ◽  
Vol 23 (2) ◽  
pp. 169-190
Author(s):  
Claudia Andrea Mikkelsen ◽  
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Guillermo Ángel Velázquez ◽  
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...  
Phytotaxa ◽  
2016 ◽  
Vol 272 (3) ◽  
pp. 173 ◽  
Author(s):  
ANABELLA AGUILERA ◽  
JIŘĺ KOMÁREK ◽  
RICARDO O. ECHENIQUE

The genus Anabaenopsis comprises about 20 morphospecies distributed in plankton of tropical, subtropical and temperate regions during warm periods. The morphological diversity and population dynamics of Anabaenopsis species from one artificial shallow lake from the Province of Buenos Aires, Argentina, was studied during summer 2005 and 2006; and from April 2012 to May 2014. The most common and abundant species were identified as A. elenkinii and A. cf. cunningtonii (first report in Argentina). Anabaenopsis circularis and A. milleri (first report in the American continent and Argentina) were less common, whereas A. nadsonii was rarely observed. Almost all species contributed to algal blooms during warm periods. However, some species were registered even under the lowest temperatures recorded (7.5 °C) and sustained biovolume also during winter (A. milleri, A. elenkinii and A. cf. cunningtonii). These results indicate that some species of the genus are capable of growing at temperatures much lower than 20°C. The species richness noted in this study suggests that there is likely much more diversity remaining on this genus to be reported in Argentina.


2020 ◽  
Vol 41 (4) ◽  
pp. 559-564
Author(s):  
Paige E. Howell ◽  
Erin Muths ◽  
Brent H. Sigafus ◽  
Blake R. Hossack

Abstract American bullfrogs (Lithobates catesbeianus) are significant invaders in many places and can negatively impact native species. Despite their impact and wide distribution, little is known about their demography. We used five years of capture mark-recapture data to estimate annual apparent survival of post-metamorphic bullfrogs in a population on the Buenos Aires National Wildlife Refuge in their invaded range in Arizona, U.S.A. This population is a potential source of colonists into breeding ponds used by the federally threatened Chiricahua leopard frog (L. chiricahuensis). Results from robust-design Cormack-Jolly-Seber models suggested that survival of bullfrogs was influenced by sex and precipitation but not body condition. Survival was higher for females (mean = 0.37; 95% , 0.72) than males (mean = 0.17; 95% , 0.49), and declined with reduced annual precipitation (mean = −0.36, 95%  = −2.09, 0.84). These survival estimates can be incorporated into models of population dynamics and to help predict spread of bullfrogs.


1982 ◽  
Vol 99 ◽  
pp. 605-613
Author(s):  
P. S. Conti

Conti: One of the main conclusions of the Wolf-Rayet symposium in Buenos Aires was that Wolf-Rayet stars are evolutionary products of massive objects. Some questions:–Do hot helium-rich stars, that are not Wolf-Rayet stars, exist?–What about the stability of helium rich stars of large mass? We know a helium rich star of ∼40 MO. Has the stability something to do with the wind?–Ring nebulae and bubbles : this seems to be a much more common phenomenon than we thought of some years age.–What is the origin of the subtypes? This is important to find a possible matching of scenarios to subtypes.


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