Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 6

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  mammals
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
EN
Gelatins from camel, bovine, and fish bones were successfully extracted by using chemical pretreatment and heating methods. The bones were demineralized for 3 days at ambient temperature using hydrochloric acid solutions (0.5–1 M), and the collagen was partially hydrolyzed by preheating in distilled water at 75–80°C for 3 h, followed by extraction temperature at 90°C for 1 h. Free-standing films of gelatin entrained with silver nanoparticles (Gel/AgNPs) at low concentrations (1.25, 2.5, and 5 mM) were synthesized as radiation dosimeters. A high-energy ultrasonic homogenizer was used to dissolve the gelatin in distilled water and to disperse the AgNPs in the gelatin. The nanocomposites’ morphology and crystallinity were investigated using scanning electron microscopy (SEM), optical absorption, and Fourier transform infrared (FTIR) spectroscopies. Dose enhancement was assessed using X-ray irradiations with beam energies below and above silver K-edge. The beam was configured by setting the X-ray generator at 15, 25.5, and 35 kV potential and a beam current of 1 mA. An X-ray detector is used to detect the number of electrons after passing through Gel/AgNPs samples. The use of AgNPs embedded in gelatin caused the enhancement of X-ray radiation absorption, and the highest percentage of linearity for the dosimeter was found to be 90% in the optical range of 395 nm to 425 nm. The preliminary results demonstrated that Gel/AgNPs material may be used in radiation dosimetry for low-energy radiotherapy sources.
EN
Noise generated by human activities has increased over the last decades as a result of human population growth, global transport and urbanization. The understanding of the effect of noise on different animal populations is mandatory to help making informed decisions in the field of natural resource management. While managers often focus on rare, charismatic species, it is important to examine the effects of noise on species that are common because abundant species have strong ecological impacts. This paper describes the influence of traffic noise on representatives of two orders of mammals: rodents and bats. I reviewed field and laboratory studies that inspected the influence of traffic noise on the following aspects of rodent and bat ecology: (1) activity and behaviour, (2) abundance and habitat use, and (3) foraging. Bats tended to be negatively affected by traffic noise, although certain species demonstrated a considerable degree of tolerance to this disturbance. The effects of traffic noise on rodents were more varied, but typically consisted of detrimental changes in vigilance-foraging trade-off. However, research on rodents appears biased towards social species which rely on alarm calls for protection.
3
Content available remote Dzikie ssaki Wielkiego Księstwa Litewskiego w pracach Jeana-Emmanuela Giliberta
EN
Among the many topics of lively scientific work that Jean Emmanuel Gilibert (1741-1814) conducted in Grodno and Vilnius, an important place is occupied by his observations of wild mammals. Royal patronage and care from Antoni Tyzenhauz, Treasurer of the Grand Duchy of Lithuania and the governor of Grodno, allowed Gilibert to keep and observe wild fauna captured by royal services in royal forests, including Białowieża Primeval Forest. Such was an origin of a female bison kept by Gilibert in Grodno. Its description, published in Indagatores naturae in Lithuania (Vilnius 1781) for decades became the primary source of information about the behaviour, food preferences and the anatomy of European bison. European science has just begun to take interest in European bison, therefore Gilibert’s account entered scientific circulation by way of French natural history encyclopaedias (mainly Georges Buffon’s Histoire naturelle) and works by Georges Cuvier or Étienne Geoffroy Saint-Hilaire. Apart from the description of European bison, Gilibert left an entire series of observations of wild mammals inhabiting the forests of the Grand Duchy of Lithuania. His accounts of moose were important in building a knowledge base for this species. In the first half of the 18th century, moose was known mainly from fantastic descriptions in Renaissance works and from prescriptions devoted to using moose hoof as the epilepsy treatment. Gilibert’s observations helped to overthrow such superstitions. Similarly, Gilibert’s first-hand information verified the widespread legends concerning brown bear (e.g. the belief that white bears, belonging to other species than polar bears, occur in Lithuania) . List of species kept and thoroughly watched by the scholar is much longer and includes lynx, wolf (and hybrids of wolves and dogs), beaver, badger, fox, hedgehog, and even white mouse. Also his comments on the species of mammals then absent in Lithuania but known either from farming or from the fur trade (wolverine, bobak marmot or steppe polecat). Also in these cases, Gilibert’s descriptions were often the first reliable information that entered the circulation in European science. His accounts were not free of errors and mistakes - but they resulted mainly from the pioneering role of his work. Some of his breeding experiments can arouse the reader’s sincere smile today, such as an attempt to feed a beaver with fish or serve cooked beans to a lynx In the margins of his mammal observations, Gilibert described also the place of their occurrence, extensive forests of the Grand Duchy of Lithuania. Read from the contemporary perspective, his thoughts are surprisingly relevant. In his praise of “primeval nature, free from human actions and not disturbed by accident or by the impatience of human desires” he sounds very similar to today’s eulogists of the primeval forest of Białowieża.
4
Content available remote Differences in global biomass and energy use between dinosaurs and mammals
EN
Estimates derived from the literature suggest that dinosaurs, even if they had a mammalian-type metabolism, produced globally much more biomass than mammals for the same amount of energy consumed. The average body mass of an individual dinosaur was several thousand times greater than in the case of mammals. Dinosaurs were one to several hundred times less numerous than mammals and, in comparison to mammals, the average number of individuals per dinosaur species was several to a dozen or so times lower than in mammals.
5
Content available remote Vistula River Valley as the ecological corridor for mammals
EN
River Vistula, one of the large (1047 km in length) European rivers preserved in semi-natural, dynamic condition, is recognized as important corridor that enables birds and fishes to migrate for long distances. To test whether the Vistula valley provides corridor function also for mammals, field surveys and habitat modelling for six target species: Bank vole Myodes glareolus, Yellow-necked mouse Apodemus flavicollis, Pine marten Martes martes, Beaver Castor fiber, Wild boar Sus scrofa, and Elk Alces alces, were under-taken in the 135 km long fragment of the valley from 529 (Warsaw) to 685 km (Włocławek). The data collected documented the occurrence of at least 51 mammals (5 Insectivora, 14 Chiroptera, 1 Lagomorpha, 16 Rodentia, 11 Carnivora, 4 Artiodactyla), and the higest species richness was noted in the fragment of river valley covered with mixed forests which makes up the protected area called Kampinos National Park. This protected area (385 km[^2]) contains coniferous and mixed forests, inland dunes, wetlands, and mosaic of extensively used meadows, pastures, alder forests and fields. The LARCH (Landscape Ecological Analysis and Rules for the Configuration of Habitat) (Van der Sluis and Romanowski 2005) model outputs indicated the potential for large viable populations of species analysed in the river valley. The LARCH SCAN analysis showed that habitats of modelled species were well connected and their local populations formed highly sustainable network. The spatial cohesion of habitats was generally highest in Kampinos NP and along the fragment of River Vistula from 580 to 618 km. It is concluded that high cohesion of habitats facilitates dispersion of animals and provides potential for gene flow among the populations in the valley. Riparian forests and islands are important for connecting the local populations of mammals of two river banks and are the key elements to provide functional continuity of the corridor along the river in places, where it is discontinued on one bank. The scenario analysis demonstrates potentially negative effects of river regulation and construction of two dams on viability of mammalian populations and spatial cohesion of their habitats. The future corridor function of the River Vistula valley depends mostly on preservation of it.s dynamic, semi-natural condition.
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.