Brood mate eviction or brood mate acceptance by brood parasitic nestlings? An experimental study with the non-evictor great spotted cuckoo and its magpie host

Some avian brood parasitic nestlings are highly virulent, destroying all host eggs or nestmates, while others accept growing up together with host nestmates. The traditional idea was that all brood parasitic nestlings would benefit from being alone in the host nest. Thus, why do nestlings of some brood parasitic species accept the company of host offspring in the nest? The trade-off hypothesis suggests that brood parasites must balance the costs and benefits of killing host young because of two major potential costs: risk of nest desertion and loss of begging assistance. Here, we test this hypothesis in a non-evictor cuckoo species, the great spotted cuckoo Clamator glandarius and its main host, the magpie Pica pica, by manipulating brood size (1–3 nestlings) and brood composition (only cuckoo, only magpie or mixed) during three consecutive breeding seasons. None of the broods were abandoned by host parents, and cuckoo nestlings alone in the nest tended to grow faster (i.e. wing length). Thus, none of the predictions of the two potential costs on which the trade-off hypothesis is based apply to the great spotted cuckoo–magpie system. Our experimental study could not directly test why chick killing has not evolved in great spotted cuckoos, but the results point in the direction of several possibilities. We suggest that chick killing in great spotted cuckoos may not be adaptive mainly because another, less costly strategy (i.e. outcompeting host nestmates for food), is efficient for successful parasitism of magpie hosts.     

Great spotted cuckoo fledglings are disadvantaged by magpie host parents when reared together with magpie nestlings

The post-fledging period is a critical phase for juvenile survival, and parental care provided during this period is a key component of avian reproductive performance. Very little is known about the relationships between foster parents and fledglings of brood parasites. Here, we present the results of a 5-year study about the relationships between fledglings of the non-evictor brood parasitic great spotted cuckoo (Clamator glandarius) and its magpie (Pica pica) foster parents. Sometimes, great spotted cuckoo and magpie nestlings from the same nest can fledge successfully, but most often parasitic nestlings outcompete host nestlings and only cuckoos leave the nest. We have studied several aspects of cuckoo post-fledging performance (i.e. feeding behaviour, parental defence and fledgling survival) in experimental nests in which only cuckoos or both magpie and cuckoo nestlings survived until leaving the nest. The results indicate that great spotted cuckoo fledglings reared in mixed broods together with magpie nestlings were disadvantaged by magpie adults with respect to feeding patterns. Fledgling cuckoos reared in mixed broods were fed less frequently than those reared in only cuckoo broods, and magpie adults approached less frequently to feed cuckoos from mixed broods than cuckoos from only cuckoo broods. These results imply that the presence of host's own nestlings for comparison may be a crucial clue favouring the evolution of fledgling discrimination; and furthermore, that the risk of discrimination at the fledgling stage probably is an important selection pressure driving the evolution of the arms race between brood parasites and their hosts.     

Design of water utilization systems in process plants with a single contaminant

This paper illustrates necessary conditions of optimality for single component water-using networks in process plants. These necessary conditions correspond to the optimal water allocation planning (WAP) problem that considers wastewater reuse on the basis of a single contaminant and where the objective is to minimize the total water intake. The conditions under which degenerate solutions are possible are also identified. Examples are discussed. A method that can be implemented by hand is also provided.     

Spatial Relations Between Floodplain Environments and Land Use – Land Cover of a Large Lowland Tropical River Valley: Pánuco Basin, México

Large lowland river valleys include a variety of floodplain environments that represent opportunities and constraints for human activities. This study integrates extensive field observations and geomorphic data with analysis of satellite remote sensing data to examine spatial relations between land use/land cover (LULC) and floodplain environments in the lower Pánuco basin of eastern Mexico. The floodplain of the lower Pánuco basin was delineated by combining a digital elevation model with a satellite image of a large flood event. The LULC was classified by combining a hybrid classification strategy with image stratification, applied to 15-m-resolution ASTER data. A geomorphic classification of floodplain environments was performed using a dry-stage image (ASTER data) and a 1993 Landsat image acquired during a large flood event. Accuracy assessment was based on aerial photographs (1:38,000), global positioning satellite ground-truthing, and a Landsat 7ETM⁺ image from 2000, which resulted in an overall accuracy of 82.9% and a KHAT of 79.8% for the LULC classification. The geomorphic classification yielded 83.5% overall accuracy, whereas the KHAT was 81.5%. LULC analysis was performed for the entire floodplain and individually within four valley segments. The analysis indicates that the study area is primarily utilized for grazing and farming. Agriculture is primarily associated with coarse-grained (sandy/silty) natural levee and point bar units close to the river channel, whereas cattle grazing occurs in distal and lower-lying reaches dominated by cohesive fine-grained (clayey) deposits, such as backswamps. In the Pánuco valley, wetlands and lakes occur within backswamp environments, whereas in the Moctezuma segments, wetlands and lakes are associated with relict channels. This study reveals considerable variation in LULC related to spatial differences in floodplain environments and illustrates the importance of considering older anthropogenic influences on the landscape. The research design should be applicable for other large lowland coastal plain river valleys where agriculture is a major component of the floodplain landscape.     

Evaluation of the Impact of Acid Mine Drainage on the Chemistry and the Macrobenthos in the Carolina Stream (San Luis – Argentina)

The purpose of this study was to evaluate the impact of acid mine drainage on the chemistry and the macrobenthos of the Carolina stream (San Luis – Argentina). Samples were obtained in the years 1997–1998 at two sites: site C₁, located 200 m upstream of the drainage, and site C₂, located 800 m downstream. The system buffer capacity was evaluated in the non – contaminated site by means of the buffer index calculation. The physico – chemical changes observed as a consequence of the contribution of acid mine drainage (AMD) were: a decreasing of pH and an increase in the ionic concentration, especially sulfate and Fe coming from the oxidation produced by chemiolithotrophic bacteria. The values obtained indicated a low buffer capacity and a high intrinsic vulnerability of the system to resist the impact originated by the AMD, producing a remarkable decreasing of pH of the receiving stream. These changes caused modifications in the original benthic community that was replaced by organisms more tolerant to the acid stress. A reduction in the abundance and in the taxonomic richness of the benthic macroinvertebrates was observed when compared with the reference station. An increase in the proportion of Chironomidae and of Acari and a decrease in the proportion of the remaining taxa were observed. The most sensitive groups were Ephemeroptera, Trichoptera and Mollusca. The community was mostly affected by the following variables: pH, conductivity, sulfate and dissolved total Fe.     

Characterization of spent AA household alkaline batteries

The aim of this work is identification of the structural components of actual domestic spent alkaline AA batteries, as well as quantification of some of their characteristics. Weight, humidity, ash content, zinc and zinc oxide on anode, manganese on cathode and other metals, potassium hydroxide on the internal components and heating values for papers, anode and cathode were determined in several batteries. As expected, cathode, anode and the steel can container are the main contributors to the 23.5 g average weight of the batteries. Cathode is also the major contributor to the positive heating value of the batteries as well as to the heavy metals content. Mercury was detected in very low levels in these mercury-free batteries. Zinc and zinc oxide amounts in the anodes are highly variable. Results obtained were compared to information on alkaline batteries in the literature from 1993 to 1995; and a positive evolution in their manufacture is readily apparent. Data from the producer of batteries shows some small discrepancies relative to the results of this experimental work.     

A comparison of the comprehensive municipal solid waste management systems of the region of Prague and the principality of Asturias. the influence of collection systems and municipality size on the waste collection and the recycling rates

Journal of Material Cycles and Waste Management - The correct management of municipal solid waste (MSW) is a critical factor in the protection of the environment, as well as a source for the...     

An approach for restoration of the water quality with emphasis on the removal of organochlorine pesticides and eutrophic conditions in tropical rivers

This work deals with an approach for the water quality restoration with emphasis on the removal of organochlorine pesticides and eutrophic conditions in tropical rivers, causing influence on the management of the central-regional aqueduct, as a source of water supply for human consumption (4 million people) and industrial production in the states of Carabobo, Cojedes and Aragua, Venezuela, testing the phytoremediation techniques through Vetiveria zizanioides (VZ) species and coupled bioreactors, Sequencing Batch Reactor (SBR) followed by an Upflow Anaerobic Filter in Three Separate Stages (UAF-3SS). Five rivers are involved known as Chirgua, Paito Guacara, Ereigüe, and Tucutunemo, whose waters have been classified as hypereutrophic, and containing organochlorine pesticides (OCPs). As a sample, for Tucutunemo River, OCPs included to DDT (dichlorodiphenyltrichloroethane) and its isomers and DRINs (Aldrin, Endrin and Dieldrin) dissolved in water and sorbed on sediments, which were measured during the dry and rainy seasons in the period 2013 to 2016, in three monitoring stations distributed in a reach of 15 km. The results indicated that p.p′-DDT concentration dissolved in water was increased up to 10 times from rainy to dry seasons, indicating that a permanent use of it is being carried out by farmers in the agricultural activity development. Steady concentrations of the DTT isomers (e.g., p.p′-DDD and p.p′-DDE) and Aldrin isomers (e.g., Dieldrin) demonstrated that the anaerobic and aerobic biodegradation processes occurred along the river and between climatic seasons. At experimental scale, VZ hydroponic system developed over a period of 6 months for the removal of nutrients demonstrated moderately low to high removal efficiencies. With respect coupled bioreactors, each bioreactor has been experimentally tested, demonstrating satisfactory performance in Chemical Oxygen Demand (COD) removal from industrial wastewater containing recalcitrant and inhibitory substances (46%–98%), which was estimated in the influent ranging from 3500 to 5500 mg/L, evidencing that coupling of bioreactors might lead to a effluent COD complying with environmental regulations.     

Development of models for predicting toxicity from sediment chemistry by partial least squares-discriminant analysis and counter-propagation artificial neural networks

There is strong interest in developing tools to link chemical concentrations of contaminants to the potential for observing sediment toxicity that can be used in initial screening-level sediment quality assessments. This paper presents new approaches for predicting toxicity in sediments, based on 10-day survival tests with marine amphipods, from sediment chemistry, by means of the application of Partial Least Squares-Discriminant Analysis (PLS-DA) and Counter-propagation Artificial Neural Networks (CP-ANNs) to large historical databases of chemical and toxicity data. The exploration of the internal structure of the developed models revealed inherent limitations of predicting toxicity from common chemical analyses of bulk contaminant concentrations. However, the results obtained in the validation of these models combined relevant values of non-error classification rate, sensitivity and specificity of, respectively, 76, 87 and 73% with PLS-DA and 92, 75 and 97% with CP-ANNs, outperforming the results reported for previous approaches.