Search results for "Conservation"
showing 10 items of 2328 documents
Diet composition and seasonal feeding patterns of a freshwater ringed seal (Pusa hispida saimensis)
2014
The Saimaa ringed seal (Pusa hispida saimensis) is one of the few freshwater seal populations worldwide. The major conservation issue of this critically endangered population is bycatch mortality. We used digestive tract content and stable isotopes (d 13 Ca ndd 15 N) to estimate the diet and seasonal feeding patterns for gaining better understanding of the seals feeding habits and potential conservation implications. The diet was similar across age groups. Altogether 15 fish species were identified and the most important were smelt (Osmerus eperlanus), ruff (Gymnocephalus cernuus), perch (Perca fluviatilis), vendace (Coregonus albula )a nd cyprinids. The high d 15 N values suggested that th…
Peri-implantitis-like medication-related osteonecrosis of the jaw: Clinical considerations and histological evaluation with confocal laser scanning m…
2021
Objective: In the recent years, an increasing number of peri-implant medication-related osteonecrosis of the jaw (PI-MRONJ) have been reported in literature, both in oncologic and osteoporotic patients. The aim of this study is to describe 19 cases of patients previously diagnosed as affected by peri-implantitis, who were treated for PI-MRONJ, with consideration on clinical and histopathological features. Materials and Methods: Patients included were affected by postmenopausal osteoporosis and were administered with different antiresorptive drugs. Due to the presence of clinical and radiological signs of peri-implantitis not healed after non-surgical periodontal treatment, they were referre…
Effects of Nile Tilapia (Oreochromis niloticus) on phytoplankton community structure and water quality: A short-term mesocosm study
2022
Nile tilapia is a highly invasive fish species, deliberately introduced into many lakes and reservoirs worldwide, sometimes resulting in significant ecosystem alterations. A short-term mesocosm experiment with and without Nile tilapia (Oreochromis niloticus) was designed to test the hypotheses that the presence of tilapia may affect phytoplankton community structure, increase nutrients availability in water column and deteriorate water quality. Nutrients, total suspended solids (TSS) and biomass of phytoplankton in different size classes (as Chl a) were measured. We found that tilapia increased the total nitrogen (TN), total dissolved nitrogen (TDN), NH4 + and TSS concentrations, deteriorat…
The comparative biological effects of spatial management measures in protecting marine biodiversity: a systematic review protocol
2015
Background: The global decline of marine biodiversity and the perceived need to protect marine ecosystems from irreparable alterations to ecosystem functioning and ecosystem service provision have produced an extensive range of spatial management measures (SMMs). The design of SMMs is a complex process often involving the integration of both conservation objectives and socio-economic priorities and the resultant trade-offs are highly dependent on the management regime in place. Future marine management is likely to involve greater use of different forms of protected areas with differing levels of protection, particularly for sites where there are multiple competing demands. Consequently, ev…
Plastic adjustments of biparental care behavior across embryonic development under elevated temperature in a marine ectotherm
2021
Abstract Phenotypic plasticity in parental care investment allows organisms to promptly respond to rapid environmental changes by potentially benefiting offspring survival and thus parental fitness. To date, a knowledge gap exists on whether plasticity in parental care behaviors can mediate responses to climate change in marine ectotherms. Here, we assessed the plasticity of parental care investment under elevated temperatures in a gonochoric marine annelid with biparental care, Ophryotrocha labronica, and investigated its role in maintaining the reproductive success of this species in a warming ocean. We measured the time individuals spent carrying out parental care activities across three…
Operative Gesichtspunkte bei der Diskussion des Weberschen Gesetzes
1977
The analysis of structures of argumentation in historical controversies is considered to be a basic contribution to the dynamics of theories. In this paper attention is drawn to the occurence of operational arguments in the history of physics. This is to be discussed especially in respect to the nineteenth-century debates on the consistency of Wilhelm Weber's electrodynamic law with the principle of conservation of energy.
Geographical assemblages of European raptors and owls
2008
Abstract In this work we look for geographical structure patterns in European raptors (Order: Falconiformes) and owls (Order: Strigiformes). For this purpose we have conducted our research using freely available tools such as statistical software and databases. To perform the study, presence–absence data for the European raptors and owl species (Class Aves) were downloaded from the BirdLife International website. Using the freely available “pvclust” R-package, we applied similarity Jaccard index and cluster analysis in order to delineate biogeographical relationships for European countries. According to the cluster of similarity, we found that Europe is structured into two main geographical…
Physics-Aware Machine Learning For Geosciences And Remote Sensing
2021
Machine learning models alone are excellent approximators, but very often do not respect the most elementary laws of physics, like mass or energy conservation, so consistency and confidence are compromised. In this paper we describe the main challenges ahead in the field, and introduce several ways to live in the Physics and machine learning interplay: encoding differential equations from data, constraining data-driven models with physics-priors and dependence constraints, improving parameterizations, emulating physical models, and blending data-driven and process-based models. This is a collective long-term AI agenda towards developing and applying algorithms capable of discovering knowled…
Self-dressing and radiation reaction in classical electrodynamics
2002
A canonical approach to self-dressing in classical electrodynamics is presented. A slowly moving, rigid charge distribution is assumed to be completely deprived of the transverse electric E⊥ at an initial time t1' and the development of this component of the field is studied for t > t1' by solving the coupled charge-field Hamilton equations of motion. The theory is specialized to charge distributions of spherical symmetry, and in particular the point-charge, the spherical shell of charge and the spherical volume of charge are considered. As for the dynamics of the charge, the radiation-reaction force during self-dressing is obtained and it is shown to be substantially different at short tim…
Topological charge selection rule for phase singularities
2009
We present a study of the dynamics and decay pattern of phase singularities due to the action of a system with a discrete rotational symmetry of finite order. A topological charge conservation rule is identified. The role played by the underlying symmetry is emphasized. An effective model describing the short range dynamics of the vortex clusters has been designed. A method to engineer any desired configuration of clusters of phase singularities is proposed. Its flexibility to create and control clusters of vortices is discussed.