Search results for " Raptor"
showing 10 items of 20 documents
Ecological specialization to fluctuating resources prevents long-distance migratory raptors from becoming sedentary on islands
2013
[Background]: The adaptive transition between behavioral strategies, such as the shift from migratoriness to sedentariness, remains an outstanding question in evolutionary ecology. Density-dependent variation in the age of first breeding has been proposed as a feasible mechanism through which long-lived migratory birds with deferred sexual maturity should become sedentary to persist on islands. Although this pattern seems to hold for most raptors and herons, a few exceptions have been identified. One of these exceptions is the Eleonora's falcon, a long-distance migratory bird, which shows one of the most peculiar adaptations in the timing of reproduction and food requirements among raptors.…
Rateless codes mitigation technique in a turbulent indoor Free Space Optics link
2014
Free Space Optics (FSO) links are affected by several impairments and, among them, optical turbulence is the most important factor that can degrade the link quality. Due to the presence of this phenomenon, the signal irradiance detected by the receiver fluctuates, thus causing erasure errors and fading events. In this work, we present an indoor Free Space Optics link, in which several turbulence conditions are generated by using two heating elements. We show that the generated turbulence causes erasure errors and packet losses during the data transmission, and we also compare the statistical distribution of the samples with the theoretical models. Moreover, we demonstrate how the applicatio…
The first inventory of birds of prey in sicilian museum collections (Italy)
2020
Natural History Museums are places of scientific dissemination and informal education, and have a fundamental role in scientific research and in preserving the historical heritage of a territory and its biodiversity. The island of Sicily, thanks to its geographic position as an inter-continental bridge in the Mediterranean, presents a notable ornithological diversity, with both sedentary species and species that migrate between Africa and Europe. For this reason, and thanks to a strong hunting tradition, Sicilian collections also depict the avifaunal assemblage historically present in the region, particularly for birds of prey, the group we focus on because of its particular ecological char…
Understanding the coexistence of competing raptors by Markov chain analysis enhances conservation of vulnerable species.
2016
Understanding ecological interactions among protected species is crucial for correct management to avoid conflicting outcomes of conservation planning. The occurrence of a superior competitor may drive the exclusion of a subordinate contestant, as in Sicily where the largest European population of the lanner falcon is declining because of potentially competing with the peregrine falcon. We measured the coexistence of these two ecologically equivalent species through null models and randomization algorithms on body sizes and ecological niche traits. Lanners and peregrines are morphologically very similar (Hutchinson ratios <1.3) and show 99% diet overlap, and both of these results predict …
Optical wireless GEO satellite-to-ground downlinks: rateless codes as solution for scintillation fading
2013
Scintillation fading can corrupt a satellite-to-ground optical wireless links with burst errors. Rateless codes, suitable for erasure channel, are able to eliminate or to reduce these communication errors. We analyzed the performances of three different rateless codes in a simulated Geo satellite-to-ground downlink.
Non-Invasive Sex Determination of Nestlings and Adult Bonelli’s Eagles Using Morphometrics
2023
Biometric analysis allows the sexing of most vertebrates, particularly birds. Birds of prey, and, especially, the Bonelli’s eagle (Aquila fasciata), show reverse sexual dimorphism (i.e., females are usually larger than males). In contrast to blood sampling, the use of morphometrics allows sex determination using a non-invasive method, and, therefore, it facilitates fieldwork. By means of a linear discriminant analysis of biometric variables, we obtained different equations that allow the sexing of nestlings and adult Bonelli’s eagles. We sampled 137 Bonelli’s eagles, 82 nestlings and 55 adults in eastern Spain during the period 2015–2022. The sexes obtained after lin…
The role of natural science collections in the biomonitoring of environmental contaminants in apex predators in support of the EU’s zero pollution am…
2022
Movalli, Paola et al.
Packet loss recovery in an indoor Free Space Optics link using rateless codes
2014
Free Space Optics (FSO) systems present some important advantages if compared to Radio Frequency links, but they can be affected by several impairments that degrade the link quality and availability. In particular, due to temporary interruptions of the line-of-sight condition between the transmitter and the receiver, packet loss can occur during data transmission. In this work, we present an indoor Free Space Optics link, in which we have systematically generated interruptions of the beam. We demonstrate how the application of the most recent rateless codes, i.e., RaptorQ codes, can strongly improve the link quality by reducing packet loss. In particular, results show that the Packet Error …
Performance Investigation of Fountaine Codes on a Simulated Terrestrial Free Space Optical Channel
2012
Correlated channel model for terrestrial Free Space Optics: performance analysis of rateless codes
2012
We describe a novel correlated channel model able to predict random temporal fluctuations of optical signal irradiance caused by scintillation. With regards to the same channel, we also report simulation results on the error mitigation performance of Luby-Transform and Raptor codes.