Loft features reveal the functioning of the young pigeon’s navigational system

It is thought that young homing pigeons are able to use information acquired en route for their initial homeward orientation. However, the cues involved and mechanisms utilised are under discussion. Blocking light-dependent route-specific information during the first leg of an outward journey detour, together with analysis of pigeons that were raised under different loft conditions, allowed us to correctly evaluate the functioning of this mechanism and, more generally, the navigational map of birds. Pigeons from the same stock were raised and kept in two different lofts. The birds in the experimental groups were transported to the release sites via detours, and light-dependent information was denied during the first half of the outward journey (no compass information was available). Control birds were transported by the most direct route and had access to all available information. In general, the results showed that the low-loft birds preferred to use magnetic compass cues, whereas the high-loft birds preferred to use navigational map cues to collect information of the first part of the outward journey. The impairments observed in the homing performances of the experimental groups highlight the reliability of information collected inside the map area. Relevant to an understanding of the route-reversal mechanism was the evidence that this mechanism is able to function in the absence of compass information (birds raised in a wind-exposed loft show a detour effect). In systems where directional information could be provided by multiple sources, processing and extracting accurate course trajectories through a common mechanism may prove more efficient and reliable.     

The effects of anaerobic reactor post-treatments by rapid filtration systems and conventional techniques

Environmental Science and Pollution Research - Although anaerobic reactors are an excellent alternative in the treatment of domestic effluents, they have the disadvantage of requiring...     

Environmental photochemical fate of pesticides ametryn and imidacloprid in surface water (Paranapanema River,São Paulo,Brazil)

In addition to direct photolysis studies, in this work the second-order reaction rate constants of pesticides imidacloprid (IMD) and ametryn (AMT) with hydroxyl radicals (HO^●), singlet oxygen (¹O₂), and triplet excited states of chromophoric dissolved organic matter (³CDOM^*) were determined by kinetic competition under sunlight. IMD and AMT exhibited low photolysis quantum yields: (1.23?±?0.07)?×?10^–2 and (7.99?±?1.61)?×?10^–3 mol Einstein^?1, respectively. In contrast, reactions with HO^● radicals and ³CDOM* dominate their degradation, with ¹O₂ exhibiting rates three to five orders of magnitude lower. The values of k_IMD,HO● and k_AMT,HO● were (3.51?±?0.06)?×?10⁹ and (4.97?±?0.37)?×?10⁹ L mol^?1 s^?1, respectively, while different rate constants were obtained using anthraquinone-2-sulfonate (AQ2S) or 4-carboxybenzophenone (CBBP) as CDOM proxies. For IMD this difference was significant, with k_IMD,3AQ2S*?=?(1.02?±?0.08)?×?10⁹ L mol^?1 s^?1 and k_IMD,3CBBP*?=?(3.17?±?0.14)?×?10⁸ L mol^?1 s^?1; on the contrary, the values found for AMT are close, k_AMT,3AQ2S*?=?(8.13?±?0.35)?×?10⁸ L mol^?1 s^?1 and k_AMT,3CBBP*?=?(7.75?±?0.80)?×?10⁸ L mol^?1 s^?1. Based on these results, mathematical simulations performed with the APEX model for typical levels of water constituents (NO₃^?, NO₂^?, CO₃^2?, TOC, pH) indicate that the half-lives of these pesticides should vary between 24.1 and 18.8 days in the waters of the Paranapanema River (São Paulo, Brazil), which can therefore be impacted by intensive agricultural activity in the region.

     

Degradation features of pesticides: a review on (metallo)porphyrin-mediated catalytic processes

Environmental Science and Pollution Research - Pesticides have been used to kill pests such as insects, fungi, rodents, and unwanted plants. Since these compounds are potentially toxic to the...     

Morphological responses and tolerance of a tree native to the Brazilian Cerrado Astronium fraxinifolium Schott to boron toxicity

Environmental Science and Pollution Research - The indiscriminate use of fertilizers and chemical pesticides can lead to boron contamination of the soil. Decontamination in general is expensive and...     

From Waste to Reuse: Manufacture of Ecological Composites Based on Biopolyethylene/wood Powder with PE-g-MA and Macaíba Oil

Journal of Polymers and the Environment - This work aimed to investigate the biopolyethylene (BioPE)/wood powder (WP) composites compatibilized with polyethylene-grafted maleic anhydride (PE-g-MA),...     

Encapsulation of Nerol Oil in Polycaprolactone Polymer and Stability Evaluation

Journal of Polymers and the Environment - The objective of this study was to obtain and characterize Nerol essential oil encapsulated in PCL. The miniemulsion and solvent evaporation method was...     

Influence of a Catalyst in Obtaining a Post-consumer Pet-Based Alkyd Resin that Meets Circular Economy Principles

Journal of Polymers and the Environment - The paper studied the influence of a catalyst, comparing it with its traditional counterparts, in the process of obtaining a polyethylene terephthalate...     

Hexavalent Chromium Sorption by Modified Cellulose Macro and Nanofibers Obtained from Eucalyptus Residues

Journal of Polymers and the Environment - Exposure to potentially toxic metallic elements (PTME) released in watercourses by industries results in irreversible damage to living beings or even...     

Screening for Selected Human Pharmaceuticals and Cocaine in the Urban Streams of Manaus,Amazonas, Brazil

Pharmaceuticals and illicit drugs are contaminants that are generally ubiquitous in wastewater treatment plant effluents with their release into the environment being well understood in North America, Europe, and Asia. There is, however, less information on the release of human pharmaceuticals and illicit drugs from regions undergoing rapid land use, economical, and social changes, such as Brazil. This encompasses many areas in the tropical zone where releases of emerging contaminants may impact pristine, bio‐diversity rich ecosystems. In this study, the occurrence of human pharmaceuticals and the illicit drug cocaine was determined in the Rio Negro and two of its tributaries that receive large amounts of untreated sewage, the Igarapé Mindu and the Igarapé do 40, passing through the city of Manaus, Brazil. In addition to cocaine and its metabolite, benzoylecognine, propranolol, diclofenac, amitriptyline, carbamazepine, carbamazepine‐epoxide, citalopram, metoprolol, carisoprolol, and sertraline were all detected in two urban tributaries at low ng/l concentrations similar to those typically found in urban surface waters. Concentrations in the Rio Negro were typically lower than detection limits due to the large level of dilution, although traces of a range of pharmaceuticals were detected in the Rio Negro in proximity of the confluence of the urban streams. The data represent new information on the emissions of pharmaceuticals from a newly industrialized region of Brazil.