نتایج جستجو برای: local birds
تعداد نتایج: 572417 فیلتر نتایج به سال:
The development of a software system which can detect and identify the ight calls of migrating birds is reported. The system rst produces a spectrogram using a Discrete Fourier transform. Calls are detected in the spectrogram using an ad-hoc combination of local peak-nding and a connectedness measure. Attributes are extracted both globally from the call and from a window moved incrementally thr...
Classification of local chicken breeds based on their phenotypic and genetic characteristics is of interest. There is a risk of extinction for the local domestic breeds of chicken, so a great attention and efforts must go to the local genotypes in all areas of the kingdom of Saudi Arabia. However, many researches inferred that Saudi local chickens exhibited a large variation in body shape and f...
The study was designed to compare the growth performance, digestibility and concentration of phosphorous (P) and calcium (Ca) in blood plasma, tibia bone and excreta in juvenile birds fed different commercially available sources of inorganic P. Day-old Hubbard broiler chickens (180) were randomly assigned to one of 4 dietary treatments (A-D), replicated three times with 15 birds per cage. All d...
1. Ecological and population processes are affected by large-scale climatic fluctuations, and top predators such as seabirds can provide an integrative view on the consequences of environmental variability on ecosystems. Here, we examine the dynamics of a southern fulmar population in Antarctica over a 39-year period and evaluate the impact of environmental variability on the life history trait...
A new hybrid algorithm of Particle Swarm Optimization and Genetic Algorithm (PSOGA) is presented to get the optimum design of truss structures with discrete design variables. The objective function chosen in this paper is the total weight of the truss structure, which depends on upper and lower bounds in the form of stress and displacement limits. The Particle Swarm Optimization basically model...
b ackground: although there are about 520 species of birds in iran, but only some of them have been checked for ectoparasites so far.the aim of this study was to check some more available species of the birds of iran for lice. m ethods: this study was performed between 2008–2010 in northern iran. for this purpose we tried to check some of the wild bird species available and mostly not checked b...
a flock of birds sweeps the sky. One moment they are circling, another they dart to the left or drop to the ground. Each move is so beautiful that it appears choreo-graphed. Furthermore, the movements of the flock seem smoother than those of any one bird in the flock. Yet, the flock has no high-level controller or even a lead bird. The phenomenon is a result of what is often called " self-organ...
The utilization of birds as pets has been recognized as one of the principal threats to global avifauna. Most of the information about the use and sale of birds as pets has been limited to areas of high biodiversity and whose impacts of anthropic actions have been widely broadcast internationally, for example for the Amazon Forest and forest remnants of Southeast Asia. The Caatinga predominates...
Effects of agricultural intensification (AI) on biodiversity are often assessed on the plot scale, although processes determining diversity also operate on larger spatial scales. Here, we analyzed the diversity of vascular plants, carabid beetles, and birds in agricultural landscapes in cereal crop fields at the field (n = 1350), farm (n = 270), and European-region (n = 9) scale. We partitioned...
In birds, fat accumulation before and during migration has been shown to be endogenously controlled and tuned by, among other factors, the Earth's magnetic field. However, our knowledge about the influence of the geomagnetic field on the fuelling in migrating birds is still limited to just a few nocturnally migrating passerine species. In order to study if variations of the magnetic field can a...
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