69 research outputs found
Taxonomic history of the iguanian lizard Liolaemus Pictus major Boulenger, with a revalidation of Liolaemus capillitas Hulse
Núñez (2004) examined the syntypes of Liolaemus pictus major Boulenger in the British Museum of Natural History and concluded, without supporting data, that this taxon is a senior synonym of Liolaemus capillitas Hulse. We show that the evidence does not support Núñez’s (2004) proposal. We first document the complex taxonomic history of L. p. major, the lack of a precise or even definitive type locality, and the implications of the latter on subsequent checklists and research. Second, we note differences between Boulenger’s (1885) type description of L. p. major and Hulse’s (1979) type description of L. capillitas. Third, we show that the syntypes of L. p. major photographed by Núñez (2004) do not exhibit the character states of L. capillitas. We conclude that L. capillitas is not a synonym of L. p. major. Based on the available evidence, the syntypes of L. p. major are probably assignable to Liolaemus elongatus from populations occurring in Patagonia (southern Argentina or adjacent Chile). However, the precise identity of the syntypes requires additional study and perhaps a type locality restriction or redefinition of L. elongatus, which is itself in a state of flux.Núñez (2004) examinó los sintipos de Liolaemus pictus major Boulenger en el Museo Británico de Historia Naturale y concluyó, sin datos que lo sostengan, que este taxón es un sinónimo señor de Liolaemus capillitas Hulse. Nosotros mostramos que la evidencia disponible no apoya la propuesta de Núñez (2004). Primero documentamos la compleja historia de L. p. major, la carencia de una localidad tipo o la restricción de una, y las implicancias de esto último en subsecuentes checklists e investigaciones. Segundo, notamos diferencias entre la descripción tipo de Boulenger (1885) de L. p. major y la descripción tipo de L. capillitas de Hulse (1979). Tercero, mostramos que los sintipos de L. p. major fotografiados por Núñez (2004) no exhiben los caracteres presentes en L. capillitas. Concluimos que L. capillitas no es un sinónimo L. p. major. Basados en la evidencia disponible, los sintipos de L. p. major son aparentemente asignables a Liolaemus elongatus de poblaciones que se encuentran en la Patagonia (sur de Argentina o adyacentes en Chile). De todos modos, la identidad precisa de los sintipos requerirá de estudio adicional y quizás la restricción de una localidad o la redefinición de L. elongatus, especie que por sà misma se encuentra pobremente definida.Fil: Espinoza, Robert E.. California State University; Estados UnidosFil: Lobo Gaviola, Fernando Jose. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Salta. Instituto de Bio y Geociencias del Noroeste Argentino; Argentina; Argentina. Universidad Nacional de Salta. Facultad de Cs.naturales. Catedra de Anatomia Comparada; ArgentinaFil: Etheridge, Richard. San Diego State University; Estados Unido
Long-Term Optical Monitoring of Eta Carinae. Multiband light curves for a complete orbital period
The periodicity of 5.5 years for some observational events occurring in Eta
Carinae manifests itself across a large wavelength range and has been
associated with its binary nature. These events are supposed to occur when the
binary components are close to periastron. To detect the previous periastron
passage of Eta Car in 2003, we started an intensive, ground-based, optical,
photometric observing campaign. We continued observing the object to monitor
its photometric behavior and variability across the entire orbital cycle. Our
observation program consisted of daily differential photometry from CCD images,
which were acquired using a 0.8 m telescope and a standard BVRI filter set at
La Plata Observatory. The photometry includes the central object and the
surrounding Homunculus nebula. We present up-to-date results of our observing
program, including homogeneous photometric data collected between 2003 and
2008. Our observations demonstrated that Eta Car has continued increasing in
brightness at a constant rate since 1998. In 2006, it reached its brightest
magnitude (V ~ 4.7) since about 1860s. The object then suddenly reverted its
brightening trend, fading to V = 5.0 at the beginning of 2007, and has
maintained a quite steady state since then. We continue the photometric
monitoring of Eta Car in anticipation of the next "periastron passage",
predicted to occur at the beginning of 2009.Comment: Accepted by A&A. The paper contains 3 figures and 2 table
Detection of high-velocity material from the wind-wind collision zone of Eta Carinae across the 2009.0 periastron passage
We report near-IR spectroscopic observations of the Eta Carinae massive
binary system during 2008-2009 using VLT/CRIRES. We detect a strong, broad
absorption wing in He I 10833 extending up to -1900 km/s across the 2009.0
spectroscopic event. Archival HST/STIS ultraviolet and optical data shows a
similar high-velocity absorption (up to -2100 km/s) in the UV resonance lines
of Si IV 1394, 1403 across the 2003.5 event. UV lines from low-ionization
species, such as Si II 1527, 1533 and C II 1334, 1335, show absorption up to
-1200 km/s, indicating that the absorption with v from -1200 to -2100 km/s
originates in a region markedly faster and more ionized than the nominal wind
of the primary star. Observations obtained at the OPD/LNA during the last 4
spectroscopic cycles (1989-2009) also display high-velocity absorption in He I
10833 during periastron. Based on the OPD/LNA dataset, we determine that
material with v < -900 km/s is present in the phase range 0.976 < phi < 1.023
of the spectroscopic cycle, but absent in spectra taken at phi < 0.947 and phi
> 1.049. Therefore, we constrain the duration of the high-velocity absorption
to be 95 to 206 days (or 0.047 to 0.102 in phase). We suggest that the
high-velocity absorption originates from shocked gas in the wind-wind collision
zone, at distances of 15 to 45 AU in the line-of-sight to the primary star.
Using 3-D hydrodynamical simulations of the wind-wind collision zone, we find
that the dense high-velocity gas is in the line-of-sight to the primary star
only if the binary system is oriented in the sky so that the companion is
behind the primary star during periastron, corresponding to a longitude of
periastron of omega ~ 240 to 270 degrees. We study a possible tilt of the
orbital plane relative to the Homunculus equatorial plane and conclude that our
data are broadly consistent with orbital inclinations in the range i=40 to 60
degrees.Comment: 18 pages, 15 figures, accepted for publication in A&A;
high-resolution PDF version available also at
http://www.mpifr.de/staff/jgroh/etacar.htm
Sección 4: Vulnerabilidad socioeconómica del sector pesquero argentino al cambio climático
En primer lugar se caracterizan los aspectos más relevantes de las dimensiones económica y social del sector pesquero argentino. Luego se realizó un análisis de la vulnerabilidad socioeconómica del sector pesquero argentino, sobre la base de las propuestas del IPCC (2014), Allison et al. (2009) y Blasiak et al. (2017).Fil: Gaviola, Saúl Ricardo. Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP); Argentina.Fil: Verón, E. Universidad Nacional de Mar del Plata. Facultad de Humanidades; Argentina.Fil: Prosdocimi, L. Ministerio de Agricultura GanaderÃa y Pesca. SubsecretarÃa de Agricultura, GanaderÃa y Pesca; Argentina.Fil: De la Garza, J. Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP); Argentina.Fil: MartÃnez, P. Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP); Argentina.Fil: Navarro, G. Ministerio de Agricultura GanaderÃa y Pesca. SubsecretarÃa de Agricultura, GanaderÃa y Pesca; Argentina.Fil: Pájaro, M. Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP); Argentina.Fil: Piedrabuena, C. Ministerio de Agricultura GanaderÃa y Pesca. SubsecretarÃa de Agricultura, GanaderÃa y Pesca; Argentina.Fil: Rotta, Lautaro Daniel. Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP); Argentina
Converting simulated total dry matter to fresh marketable yield for field vegetables at a range of nitrogen supply levels
Simultaneous analysis of economic and environmental performance of horticultural crop production requires qualified assumptions on the effect of management options, and particularly of nitrogen (N) fertilisation, on the net returns of the farm. Dynamic soil-plant-environment simulation models for agro-ecosystems are frequently applied to predict crop yield, generally as dry matter per area, and the environmental impact of production. Economic analysis requires conversion of yields to fresh marketable weight, which is not easy to calculate for vegetables, since different species have different properties and special market requirements. Furthermore, the marketable part of many vegetables is dependent on N availability during growth, which may lead to complete crop failure under sub-optimal N supply in tightly calculated N fertiliser regimes or low-input systems. In this paper we present two methods for converting simulated total dry matter to marketable fresh matter yield for various vegetables and European growth conditions, taking into consideration the effect of N supply: (i) a regression based function for vegetables sold as bulk or bunching ware and (ii) a population approach for piecewise sold row crops. For both methods, to be used in the context of a dynamic simulation model, parameter values were compiled from a literature survey. Implemented in such a model, both algorithms were tested against experimental field data, yielding an Index of Agreement of 0.80 for the regression strategy and 0.90 for the population strategy. Furthermore, the population strategy was capable of reflecting rather well the effect of crop spacing on yield and the effect of N supply on product grading
Eta Carinae -- Physics of the Inner Ejecta
Eta Carinae's inner ejecta are dominated observationally by the bright
Weigelt blobs and their famously rich spectra of nebular emission and
absorption lines. They are dense (n_e ~ 10^7 to 10^8 cm^-3), warm (T_e ~ 6000
to 7000 K) and slow moving (~40 km/s) condensations of mostly neutral (H^0)
gas. Located within 1000 AU of the central star, they contain heavily
CNO-processed material that was ejected from the star about a century ago.
Outside the blobs, the inner ejecta include absorption-line clouds with similar
conditions, plus emission-line gas that has generally lower densities and a
wider range of speeds (reaching a few hundred km/s) compared to the blobs. The
blobs appear to contain a negligible amount of dust and have a nearly dust-free
view of the central source, but our view across the inner ejecta is severely
affected by uncertain amounts of dust having a patchy distribution in the
foreground. Emission lines from the inner ejecta are powered by photoionization
and fluorescent processes. The variable nature of this emission, occurring in a
5.54 yr event cycle, requires specific changes to the incident flux that hold
important clues to the nature of the central object.Comment: This is Chapter 5 in a book entitled: Eta Carinae and the Supernova
Impostors, Kris Davidson and Roberta M. Humphreys, editors Springe
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