Search results for "Stock"
showing 10 items of 878 documents
A version of Hake’s theorem for Kurzweil–Henstock integral in terms of variational measure
2019
Abstract We introduce the notion of variational measure with respect to a derivation basis in a topological measure space and consider a Kurzweil–Henstock-type integral related to this basis. We prove a version of Hake’s theorem in terms of a variational measure.
On Variational Measures Related to Some Bases
2000
Abstract We extend, to a certain class of differentiation bases, some results on the variational measure and the δ-variation obtained earlier for the full interval basis. In particular the theorem stating that the variational measure generated by an interval function is σ-finite whenever it is absolutely continuous with respect to the Lebesgue measure is extended to any Busemann–Feller basis.
Parasites as indicators of social structure and stock identity of marine mammals
1995
Abstract Introduction: the use of parasites as biological indicators of marine mammals has not yet received all the necessary attention. The aim of this review is to show the value of parasite data in studies of stock identity and social structure. Methods: the application of the technique to marine mammals is hampered by the lack of control over sampling conditions and the paucity of information about the biology of their parasites. Relevant criteria for, suitable parasite tags are discussed. Case studies: previous work on marine mammals is presented to illustrate the usefulness and limitations of parasite data. A study of pilot whales revealed that differences in helminth infections betwe…
Determinants of jaguar occupancy at the northern range edge
2020
Identifying factors promoting jaguar (Panthera onca) occupancy is crucial for planning effective conservation and management actions that can contribute to long-term population viability. We used camera-trapping and modeled factors affecting detection and occupancy for jaguars in Sonora at 149 sites during August-November 2008 and 2009. We measured 24 covariates presumed to affect detection (n = 6) and occupancy (n = 18) at camera sites, including sampling period and various habitat characteristics. We obtained 29 jaguar detections at 19 sites (naive occupancy = 0.12) in 5455 trap-days of effort. Jaguar detectability (p = 0.16 +/- 0.05) was negatively affected by human presence and varied b…
A population genetics view of animal domestication
2012
The fundamental shift associated with the domestication of plants and animals allowed for a dramatic increase in human population sizes and the emergence of modern society. Despite its importance and the decades of research devoted to studying it, questions regarding the origins and processes of domestication remain. Here, we review recent theoretical advances and present a perspective that underscores the crucial role that population admixture has played in influencing the genomes of domestic animals over the past 10000 years. We then discuss novel approaches to generating and analysing genetic data, emphasising the importance of an explicit hypothesis-testing approach for the inference of…
Natural recruitment contributes to high densities of grass carp Ctenopharyngodon idella (Valenciennes, 1844) in Western Europe
2015
Introductions of grass carp, well known for their potentially negative ecosystem effects, have been performed in several countries around the world. As the species was considered unable to reproduce naturally under non-native environmental conditions, little attention was initially given to its invasive potential. We studied an area in northern-Italy where, contrary to expectations, introductions that were performed in the early 80s still exert a considerable pressure on aquatic macrophytes. In order to reveal whether the observed population dynamics are the result of natural events or stocking we analysed the density, age- and size-structure of the grass carp population and the migration p…
Role of Antioxidants in Cooled Liquid Storage of Mammal Spermatozoa
2021
Cooled preservation of semen is usually associated with artificial insemination and genetic improvement programs in livestock species. Several studies have reported an increase in reactive oxidative species and a decrease in antioxidant substances and sperm quality parameters during long-term semen storage at refrigerated temperatures. The supplementation of antioxidants in extenders before refrigeration could reduce this detrimental effect. Various antioxidants have been tested, both enzymatic, such as superoxide dismutase and catalase, and non-enzymatic, such as reduced glutathione, vitamins E and C and melatonin. However, the problem of oxidative stress in semen storage has not been full…
Human and animal fascioliasis in andean regions of argentina: lymnaeid vectors and livestock reservoirs
2018
La fascioliasis es una enfermedad parasitaria zoonótica causada en América por Fasciola hepatica. Produce serias pérdidas económicas a la ganadería y es un importante problema en salud pública a nivel mundial. Las más altas prevalencias en humanos se hallan en regiones andinas. La especie de lymnaeido vector involucrada condiciona el escenario epidemiológico. En Argentina existía gran controversia acerca de las especies de lymnaeidos vectores presentes. Además de los bovinos, escasos estudios han considerado el rol que cumplirían otras especies domésticas y silvestres como reservorios. La fascioliasis humana ha sido considerada una enfermedad de escasa relevancia. El objetivo del presente t…
CONSIDERATIONS OVER A BIOGAS PLANT COMPONENTS
2014
This paper starts from the conviction that one of the main environmental problems of today’s society is the continuously increasing production of organic wastes. In many countries, sustainable waste management have become major political priorities in order to reduce pollution and greenhouse gas emissions and to avoid, as much as possible, global climate changes. This problem becomes more and more present in our country too. Production of biogas through anaerobic digestion of animal manure and slurries as well as of a wide range of digestible organic wastes, converts these substrates into renewable energy and offers a natural fertiliser for agriculture. That is why we consider that biogas p…
A review of methods to assess connectivity and dispersal between fish populations in the Mediterranean Sea
2013
Fish populations are linked to each other via dispersal of individuals as eggs, larvae, juveniles or adults. The understanding of this process, known as connectivity, has a pivotal role for the management of overexploited fish stocks and the development of accurate conservation strategies. Knowledge on connectivity and fish movements is considered fundamental toward the correct design of marine protected area (MPA) networks for the achievement of the benefits of protection. Connectivity patterns are still largely unknown worldwide. A general lack of knowledge is particularly evident for the Mediterranean Sea where few studies dealing with this topic have been carried out and some methods, c…