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991.
Deseada Parejo Étienne Danchin Nadia Silva Joel F. White Amélie N. Dreiss Jesús M. Avilés 《Behavioral ecology and sociobiology》2008,62(10):1569-1579
Sympatric species sharing requirements are competitors, but recent evidence suggests that heterospecifics may also be used
as a source of information. The heterospecific habitat copying hypothesis proposes that individuals of one species might use
information inadvertently produced by the breeding performance of individuals of other species to assess habitat quality whenever
the two species share needs. In this study, we provide the first experimental test of this hypothesis by examining whether
the manipulated reproductive success of blue tits (Cyanistes caeruleus) is used as heterospecific inadvertent social information (ISI) in breeding-habitat selection by sympatric great tits (Parus major). The reproductive success of blue tits was manipulated 1year at the scale of patches by transferring nestlings from decreased
to increased patches. No evidence was found of great tits using the reproductive success of blue tits as a source of heterospecific
ISI. However, dispersal decisions by adult great tits correlated with information on con- and heterospecific densities, which
constitute other sources of ISI. As density and breeding performance are tightly intertwined forms of information, the difficulty
in distinguishing between them might lead great tits to use heterospecific ISI more in the form of density than breeding performance
when making dispersal decisions. 相似文献
992.
In this work we have used fuzzy rule-based systems to elaborate a predator–prey type of model to study the interaction between aphids (preys) and ladybugs (predators) in citriculture, where the aphids are considered as transmitter agents of the Citrus Sudden Death (CSD). Simulations were performed and a graph was drawn to show the prey population, the potentiality of the predators, and a phase-plane. From this phase-plane, a classic model of the Holling–Tanner type is fitted and its parameters were found. Finally, we have studied the stability of the critical points of the Holling–Tanner model. 相似文献
993.
Densely occupied drainage basins and coastal zones in developing countries that are facing economic growth are likely to suffer from moderate to severe environmental impacts regarding different issues. The catchment basins draining towards the Atlantic coast from northeastern to southern Brazil include a wide range of climatic zones and diverse ecosystems. Within its borders lies the Atlantic rain forest, significant extensions of semiarid thorn forests (caatinga), vast tree and scrub woodlands (cerrado) and most of the 6670 km of the Brazilian coast and its marine ecosystems. In recent decades, human activities have increasingly advanced over these natural resources. Littoralization has imposed a burden on coastal habitats and communities. Most of the native vegetation of the cerrado and caatinga was removed and only 7% of the original Atlantic rainforest still exists. Estuaries, bays and coastal lagoons have been irreversibly damaged. Land uses, damming and water diversion have become the major driving forces for habitat loss and aquatic ecosystem modification. Regardless of the contrast between the drought-affected northeastern Brazil and the much more prosperous and industrialized southeastern/southern Brazil, the impacts on habitat and communities were found equally severe in both cases. Attempts to halt environmental degradation have not been effective. Instead of focusing on natural resources separately, it is suggested that more integrated environmental policies that focus on aquatic ecosystems integrity are introduced. 相似文献
994.
Medical wastes management in the south of Brazil 总被引:2,自引:0,他引:2
In developing countries, solid wastes have not received sufficient attention. In many countries, hazardous and medical wastes are still handled and disposed together with domestic wastes, thus creating a great health risk to municipal workers, the public and the environment. Medical waste management has been evaluated at the Vacacai river basin in the State of Rio Grande do Sul, Brazil. A total of 91 healthcare facilities, including hospitals (21), health centers (48) and clinical laboratories (22) were surveyed to provide information about the management, segregation, generation, storage and disposal of medical wastes. The results about management aspects indicate that practices in most healthcare facilities do not comply with the principles stated in Brazilian legislation. All facilities demonstrated a priority on segregation of infectious-biological wastes. Average generation rates of total and infectious-biological wastes in the hospitals were estimated to be 3.245 and 0.570 kg/bed-day, respectively. 相似文献
995.
Guppy (Poecilia reticulata) was selected to investigate the effects of chlorpyrifos on reproductive performances. Male and female guppy with proven fertility were selected from our own colony and the groups of fish (n=72/group) were exposed to pre-determined chlorpyrifos concentrations (0.002 microg/l, 2 microg/l) based on the 96-h LC50 for guppy. Mating behavior of males was recorded on the 2nd day of exposure. Offspring were counted and survival recorded on the 14th day. Gonopodial thrusts (8/15 min) in 0.002 microg/l and (4/15 min) in 2 microg/l were significantly different from the control group (11/15 min). Similarly, live birth reduced significantly to 8/female in 2 microg/l compared to 27/female in the control group. Survival of offspring after 14 days was reduced to 47% in the 2 microg/l group compared to 94% of survival in the control. Our findings demonstrate that low soluble concentrations of chlorpyrifos affect mating behavior, number of offspring and offspring survival of guppy. 相似文献
996.
997.
In order to contribute to a future waste management policy related to the presence of technologically enhanced natural occurring radioactive material (TENORM) in the Brazilian petroleum industry, the present work presents the chemical composition and the (226)Ra and (228)Ra content of sludge and scales generated during the offshore E and P petroleum activities in the Campos Basin, the primary offshore oil production region in Brazil. The (226)Ra and (228)Ra content on 36 sludge and scales samples were determined by gamma-spectrometry. Based on X-ray diffractometry results, a chemical analysis schema for these samples was developed. The results have shown that scales are 75% barium and strontium sulfates, with a mean (226)Ra and (228)Ra content of 106 kBq kg(-1) and 78 kBq kg(-1), respectively. On the other hand, sludge samples have a much more complex chemical composition than the scales. The (226)Ra and (228)Ra content in sludge also varies much more than the content observed in the scales samples and ranged from 0.36 to 367 kBq kg(-1) and 0.25 to 343 kBq kg(-1), respectively. 相似文献
998.
Cheeseman CR Monteiro da Rocha S Sollars C Bethanis S Boccaccini AR 《Waste management (New York, N.Y.)》2003,23(10):907-916
The <8 mm fraction of aged incinerator bottom ash from a commercial incinerator (energy from waste) plant has been collected at regular intervals, characterised and processed to form ceramic materials. Ashes were sieved, wet ball milled, dried, compacted and sintered at temperatures between 1080 and 1115 degrees C. Variations in the chemical composition and mineralogy of the milled ash, and the mineralogy, physical properties and leaching of sintered products have been assessed. Milling produces a raw material with consistent chemical and mineralogical composition with quartz (SiO(2)), calcite (CaCO(3)), gehlenite (Ca(2)Al(AlSi)O(7)) and hematite (Fe(2)O(3)) being the major crystalline phases present. Different batches also milled to give consistent particle size distributions. Sintering milled incinerator bottom ash at 1110 degrees C produced ceramics with densities between 2.43 and 2.64 g/cm(-3) and major crystalline phases of wollastonite (CaSiO(3)) and diopside (CaMgSi(2)O(6)). The sintered ceramics had reduced acid neutralisation capacity compared to the as-received ash and exhibited reduced leaching of Ca, Mg, Na and K under all pH conditions. The leaching of heavy metals was also significantly reduced due to encapsulation and incorporation into glassy and crystalline phases, with Cu and Al showing greatly reduced leaching under alkali conditions. 相似文献
999.
The immune system of vertebrates consists of several components that partly interact and complement each other. Therefore, the assessment of the overall effectiveness of immune defence requires the simultaneous measurement of different immune components. In this study, we investigated intraspecific variability of innate [i.e. natural antibodies (NAb) and complement] and acquired (i.e. leucocyte profiles) immunity and its relationship with fitness correlates (i.e. blood parasite load and reproductive success in adults and body mass and survival until fledging in nestlings) in the Eurasian kestrel Falco tinnunculus. Immunity differed between nestlings and adults and also between adult males and females. Adult kestrels with higher levels of complement were less parasitised by Haemoproteus, and males with higher values of NAbs showed a higher reproductive success. In nestlings, the H/L ratio was negatively related to body mass. Survival until fledging was predicted by all measured immunological variables of nestlings as well as by their fathers' level of complement. This is the first time that innate immunity is linked to survival in a wild bird. Thus, intraspecific variation in different components of immunity predicts variation in fitness prospects in kestrels, which highlights the importance of measuring innate immune components together with components of the acquired immunity in studies assessing the effectiveness of the immune system in wild animals. 相似文献
1000.
Cabreira SF Schultz CL Bittencourt JS Soares MB Fortier DC Silva LR Langer MC 《Die Naturwissenschaften》2011,98(12):1035-1040
Post-Triassic theropod, sauropodomorph, and ornithischian dinosaurs are readily recognized based on the set of traits that
typically characterize each of these groups. On the contrary, most of the early members of those lineages lack such specializations,
but share a range of generalized traits also seen in more basal dinosauromorphs. Here, we report on a new Late Triassic dinosaur
from the Santa Maria Formation of Rio Grande do Sul, southern Brazil. The specimen comprises the disarticulated partial skeleton
of a single individual, including most of the skull bones. Based on four phylogenetic analyses, the new dinosaur fits consistently
on the sauropodomorph stem, but lacks several typical features of sauropodomorphs, showing dinosaur plesiomorphies together
with some neotheropod traits. This is not an exception among basal dinosaurs, the early radiation of which is characterized
by a mosaic pattern of character acquisition, resulting in the uncertain phylogenetic placement of various early members of
the group. 相似文献