2,252 research outputs found
Estudios ornitológicos urbanos en Colombia: revisión de literatura
This paper reviews what has been published in peer-reviewed journals about birds in Colombian cities, complementing an important Latin American review article that was recently published. This review identifies 55 papers dealing with 12 Colombian cities which exceeds by 50 the the number of studies previously considered. Species lists and Ecological Studies are the most frequent studies. Medellín is the city with the most studies (26 papers), whereas Bogotá (nine), Cali and Popayán (four each) had fewer publications. Although our review detects important publications not previously considered, we conclude that urban ornithology in Colombia is still in its infancy considering the duration, number, quality, impact and depth of studies so far published.
PACS: 87.23.-n
MSC: 92D40Este artículo examina la información que se ha producido en revistas arbitradas sobre las aves de las ciudades colombianas, complementando un artículo de revisión Latinoamericano publicado recientemente. Esta revisión identifica un total de 55 artículos en doce ciudades colombianas, lo cual excede en 50 el número de estudios previamente considerado. Los Listados de Especies y los Estudios Ecológicos son los estudios más frecuentes. La ciudad donde más trabajos se han realizado es Medellín (26), seguid por Bogotá (nueve), Cali y Popayán (ambas con cuatro trabajos). Aunque nuestra revisión registra un número mayor de publicaciones de lo que se asumía previamente, concluimos que la ornitología urbana colombiana es todavía una área joven, en tiempo, número, calidad, impacto y profundidad de las investigaciones publicadas hasta el momento.
PACS: 87.23.-n
MSC: 92D4
Registros notables de la guagua loba Dinomys branickii (Rodentia: Dinomyidae) en Antioquia, Colombia.
The pacarana Dinomys branickii (Peters 1873), is the second largest rodent in Colombia and the only living representative of the Dinomyidae family. The species has a restricted distribution to the Andes Mountains.La guagua loba, Dinomys branickii (Peters 1873), es el segundo roedor más grande de Colombia y la única representante viviente de la familia Dinomyidae. La especie presenta una distribución restringida a la Cordillera de los Andes
Un caso potencial de depredación de puercoespín (Coendou sp.) por Ocelote (Leopardus pardalis) en La Reserva Natural La Mesenia-Paramillo, Jardín, Antioquia
Here we document evidence of the possible consumption of a porcupine (Coendou sp.) By an Ocelot in a montane forest southwest of Antioquia, Colombia. This represents a remarkable record regarding a new food item (Coendou sp.) In the Ocelot diet in high mountain areas in Colombia. The location of the records is located at 2,100 meters above sea level in the Western Cordillera, in the Natural Reserve La MeseniaParamillo, in the municipality of Jardín, southwest of AntioquiaAquí documentamos evidencia del posible consumo de un puercoespín (Coendou sp.) por un Ocelote en un bosque montano al suroeste de Antioquia, Colombia. Esto representa un registro notable en cuanto a un nuevo ítem alimentario (Coendou sp.) en la dieta del Ocelote en zonas de alta montaña en Colombia. La localidad de los registros está ubicada a 2.100 msnm en la Cordillera Occidental, en la Reserva Natural La MeseniaParamillo, del municipio de Jardín, al suroeste de Antioqui
Recruitment of the exotic weakfish at its southernmost limit in Europe: a preliminary assessment.
Since its first record in Europe as an exotic species back in 2009 at the Schelde estuary (Belgium), the weakfish Cynoscion regalis -native from North America East coast- has increased its presence in the Iberian Peninsula waters. Identified for the first time in the Guadalquivir River estuary (2011) and later in the Sado estuary (2014), C. regalis population is increasing in the Gulf of Cadiz and is becoming a fisheries resource. Its introduction into Europe probably occurred through maritime transatlantic trade. Morais et al (2017) suggested that weakfish could have been introduced through multiple independent ballast water release events. The Guadalquivir, Sado and Schelde estuaries show similar transoceanic ship traffic to upstream important commercial ports, supporting multiple direct or secondary transatlantic introductions among European ports. The first genetic studies suggest that C. regalis populations in southern European estuaries are connected and come from a single transoceanic commercial route. Currently, the Gulf of Cadiz maintains a well-established population with frequent catches by artisanal fishing, especially in coastal waters and the estuary, where it is sold in local markets of the surrounding cities.
The population in the area is constituted by mature specimens (ranging from 234 to 453 mm) that are using the estuary as a spawning area, where larvae and juvenile have also been found. In recent years, an increase in the abundance of larvae and juvenile has been observed through monthly samplings in the estuary, which indicates the culmination of the complete life cycle in the Gulf of Cadiz. These findings represent new evidence that the Guadalquivir estuary constitutes a remarkable nursery habitat for this species. This could have effects on native fauna and the ecosystem, which is why it is currently under study and evaluation (EcoInvadiz project) for helping the local Administration to establish, if needed, an appropriate management program
The Light Stop Scenario from Gauge Mediation
In this paper we embed the light stop scenario, a MSSM framework which
explains the baryon asymmetry of the universe through a strong first order
electroweak phase transition, in a top-down approach. The required low energy
spectrum consists in the light SM-like Higgs, the right-handed stop, the
gauginos and the Higgsinos while the remaining scalars are heavy. This spectrum
is naturally driven by renormalization group evolution starting from a heavy
scalar spectrum at high energies. The latter is obtained through a
supersymmetry-breaking mix of gauge mediation, which provides the scalars
masses by new gauge interactions, and gravity mediation, which generates
gaugino and Higgsino masses. This supersymmetry breaking also explains the \mu\
and B_\mu\ parameters necessary for electroweak breaking and predicts small
tri-linear mixing terms A_t in agreement with electroweak baryogenesis
requirements. The minimal embedding predicts a Higgs mass around its
experimental lower bound and by a small extension higher masses m_H\lesssim 127
GeV can be accommodated.Comment: 20 pages, 3 figures; v2: changes in the conventions; v3: more details
on the Higgs mass prediction, version published in JHE
Phenomenology of the nMSSM from colliders to cosmology
Low energy supersymmetric models provide a solution to the hierarchy problem
and also have the necessary ingredients to solve two of the most outstanding
issues in cosmology: the origin of dark matter and baryonic matter. One of the
most attractive features of this framework is that the relevant physical
processes are related to interactions at the weak scale and therefore may be
tested in collider experiments in the near future. This is true for the Minimal
Supersymmetric Standard Model (MSSM) as well as for its extension with the
addition of one singlet chiral superfield, the so-called nMSSM. It has been
recently shown that within the nMSSM an elegant solution to both the problem of
baryogenesis and dark matter may be found, that relies mostly on the mixing of
the singlet sector with the Higgs sector of the theory. In this work we review
the nMSSM model constraints from cosmology and present the associated collider
phenomenology at the LHC and the ILC. We show that the ILC will efficiently
probe the neutralino, chargino and Higgs sectors, allowing to confront
cosmological observations with computations based on collider measurements. We
also investigate the prospects for a direct detection of dark matter and the
constraints imposed by the current bounds of the electron electric dipole
moment in this model.Comment: 44 pp, 10 figures; Fig.9 replaced; discussion on CP violation
extended and references added; few minor additions in text about details of
the cut
Renormalization of the QED of self-interacting second order spin 1/2 fermions
We study the one-loop level renormalization of the electrodynamics of spin
1/2 fermions in the Poincar\'e projector formalism, in arbitrary covariant
gauge and including fermion self-interactions, which are dimension four
operators in this framework. We show that the model is renormalizable for
arbitrary values of the tree level gyromagnetic factor g within the validity
region of the perturbative expansion, \alpha g^2 << 1. In the absence of tree
level fermion self-interactions, we recover the pure QED of second order
fermions, which is renormalizable only for |g|=2. Turning off the
electromagnetic interaction we obtain a renormalizable Nambu-Jona-Lasinio-like
model with second order fermions in four space-time dimensions.Comment: 32 pages, 9 figures. Published versio
Habitat filtering and inferred dispersal ability condition across-scale species turnover and rarity in Macaronesian island spider assemblages
Publisher Copyright: © 2021 The Authors. Journal of Biogeography published by John Wiley & Sons Ltd.Aim: Habitat diversity has been linked to the diversity and structure of island communities, however, little is known about patterns and processes within habitats. Here we aim to determine the contributions of habitat type and inferred dispersal frequency to the differences in taxonomic structure between assemblages in the same island habitat. Location: The Macaronesian archipelagos (Azores, Madeira, the Canary Islands and Cabo Verde). Taxon: Spiders (Araneae). Methods: We established forest and dry habitat sites (each with five plots) on two islands per archipelago. We collected spiders using standardised sampling protocols. We tested the differences in beta diversity separately for each habitat and for each inferred category of ballooning (an aerial dispersal strategy) frequency across geographic scales through nested non-parametric permutational multivariate analyses of variance. We then tested whether ballooning and habitat influenced heterogeneity in species composition (dispersion in beta diversity) in the two habitat types. We analysed the effects of habitat and ballooning on species abundance distribution (SAD) and rarity by fitting Gambin models and evaluating the contribution of ballooning categories to SAD. Results: Communities of the same archipelago and habitat were taxonomically more similar, and beta diversity increased with geographic scale, being greater in dry habitats. There was greater species replacement among assemblages in dry habitats than in forests, with greater differences for rare ballooners. There were no differences in SAD between habitats although dry habitat sites seemed to harbour more species with low abundances (rare species) than forests. Main conclusions: Habitat type does not only condition the differences between spider assemblages of the same habitat but also the scale at which they occur. These differences may be determined by the heterogeneity in the physical structure of each habitat as well as how much this structure facilitates aerial dispersal (ballooning), and should be considered in theories/hypotheses on island community assembly as well as in conservation strategies.Peer reviewe
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