Interspecific observational memory in a non-caching Parus species,the great tit Parus major

Scatter-hoarding passerine birds have become a model system for research on spatial memory capacity. This research has focussed on two families, the Corvidae (crows, jays, nutcrackers, etc.) and the Paridae (titmice and chickadees). Corvids are considered to have highly developed cognitive skills that sometimes have been compared with the great apes. Even though pilfering, or stealing of caches made by others, is common among scatter-hoarding birds, the ability to memorize positions of caches made by others has only been demonstrated in some species of corvids. In parids, the ability to memorize positions of caches made by others has not been demonstrated. In a laboratory experiment, we allowed caged great tits to observe caching marsh tits and found that they remembered caching locations both 1 and 24 h after observation. This is the first time observational spatial learning of this type explicitly has been demonstrated in a parid. This ability is surprising since the great tit is not itself a food hoarder, meaning that it may not have the special memory adaptations in the brain that specialized food hoarders possess. Also, the memorization process in an observing pilferer may differ from the memorization that hoarders make of own caches. For example, the typical close inspection of the cache that hoarding parids do after caching will usually not be possible from a distance. Also, the visual perspective of the observing scrounger may be different from that of the hoarder, meaning that some understanding of allocentric space may be required.     

Climate change impacts on the leaching of a heavy metal contamination in a small lowland catchment

The Keersop catchment (43km(2)) in the south of The Netherlands has been contaminated by the emissions of four zinc ore smelters. The objective of this study was to assess the effects of future projected climate change on the hydrology and the leaching of heavy metals (i.e. Cd and Zn) in the catchment. The numerical, quasi-2D, unsaturated zone Soil Water Atmosphere Plant model was used with 100-year simulated daily time series of precipitation and potential evapotranspiration. The time series are representative of stationary climates for the periods 1961-1990 ("baseline") and 2071-2100 ("future"). The time series of future climate were obtained by downscaling the results of eight regional climate model (RCM) experiments, driven by the SRES A2 emissions scenario, using change factors for a series of climate statistics and applying them to stochastic weather generator models. The time series are characterized by increased precipitation in winter, less precipitation in summer, and higher air temperatures (between 2°C and 5°C) throughout the year. Future climate scenarios project higher evapotranspiration rates, more irrigation, less drainage, lower discharge rates and lower groundwater levels, due to increased evapotranspiration and a slowing down of the groundwater system. As a result, lower concentrations of Cd and Zn in surface water are projected. The reduced leaching of heavy metals, due to drying of the catchment, showed a positive impact on a limited aspect of surface water quality.     

Effects of 2,4-dichlorophenoxyacetic acid formulation on medulla spinalis of Poecilia reticulata: A histopathological study

This study investigated the possible effects of a commonly used foliar herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) formulation on medulla spinalis of lebistes. Fish were exposed to 2,4-D (15, 30, 45 mg L⁻¹), behavioral changes were monitored. Fish were fixed, histopathological examination was carried out on sections taken from the upper parts of the fish body. Histopathology showed increase in neuronal loss, swelling indicating formation of intracellular edema, vacuolization noticed as the formation of vacuoles within or adjacent to cells, deformation in the Nissl granules, pyknosis and gliosis in medulla spinalis. Behavioral changes were decreased general activity, grouping, shortness in breath, sudden rotations and jumping, loss of equilibrium and colour. In conclusion, this commercial formulation of 2,4-D is considerably neurotoxic to lebistes. Fish constitute the last link in the chain of the feeding cycle in aquatic eco-system, number of studies investigating acute and chronic neurotoxicity of various herbicides in fish should be increased.     

Degassing of H/He, CFCs and SF6 by denitrification: Measurements and two-phase transport simulations

The production of N₂ gas by denitrification may lead to the appearance of a gas phase below the water table prohibiting the conservative transport of tracer gases required for groundwater dating. We used a two-phase flow and transport model (STOMP) to study the reliability of ³H/³He, CFCs and SF₆ as groundwater age tracers under agricultural land where denitrification causes degassing. We were able to reproduce the amount of degassing (R² = 69%), as well as the ³H (R² = 79%) and ³He (R² = 76%) concentrations observed in a ³H/³He data set using simple 2D models. We found that the TDG correction of the ³H/³He age overestimated the control ³He/³He age by 2.1 years, due to the accumulation of ³He in the gas phase. The total uncertainty of degassed ³H/³He ages of 6 years (± 2 σ) is due to the correction of degassed ³He using the TDG method, but also due to the travel time in the unsaturated zone and the diffusion of bomb peak ³He. CFCs appear to be subject to significant degradation in anoxic groundwater and SF₆ is highly susceptible to degassing. We conclude that ³H/³He is the most reliable method to date degassed groundwater and that two-phase flow models such as STOMP are useful tools to assist in the interpretation of degassed groundwater age tracer data.     

Freshwater crayfish Astacus leptodactylus (Eschscholtz, 1823) accumulates and depurates copper

Cu accumulation and depuration in various tissues of the crayfish Astacus leptodactylus was investigated. Adult specimens were exposed to 0.5, 2.5 and 5.0 mg Cu/L under static conditions for three weeks. At the end of the 3rd week the specimens were divided into three groups and left in dechlorinated water for either 1, 2 or 3 weeks for depuration. After 7, 14 and 21 days, four crayfish from each group were instantaneously sacrificed. All crayfish were dissected into their hepatopancreas, gill, abdominal muscle and exoskeleton tissues for evaluation of Cu accumulation in each. The following accumulation pattern was obtained in decreasing order; hepatopancreas > gills > exoskeleton > abdominal muscles with values of 94.13, 84.86, 66.13 and 11.43 mg/L, respectively. The observed Cu depuration throughout the study was found to be time-dependent. Based on the present work we conclude that crayfish has a great potential for rapid accumulation and depuration of Cu in fresh water.     

Determination of potential allergenic fungal flora and its clinical reflection in suburban elementary schools in Izmir

In this research, in order to determine mean fungus counts, indoor and outdoor air samples were taken in five elementary school buildings located in the city center of Seferihisar, Izmir (45 km from Izmir) within a 1-year period between March and April 2004, and between January and February 2005 representing similar climatic characteristics. Five samples, three from three classes where 5–8, 10–12, and 12–15 age group students attended, one from the corridors, and one from outside the buildings in all the schools, were taken for each period. Within the period of the study, in indoor and outdoor air samples, 7,122 microfungus colonies were counted. Sixty-four species were identified that belong to 17 genera as a result of the identification of isolates obtained. Skin prick tests were applied to 55 out of a total of 117 teachers by the clinicians. According to these test results, 24 teachers were sensitive to at least one agent. Results revealed that, in terms of mold counts, the difference between the schools and the difference between the times (periods) were statistically significant (p?< 0.05).     

Characterization and COD fractionation of domestic wastewaters

Results of a comprehensive study are reported for wastewater characterization in relation to modelling and design of biological nutrient removal systems for the Metropolitan Area of Istanbul. Domestic sewage quality was experimentally assessed in terms of major polluting parameters. Size distribution and calculation of significant ratios such as BOD5:COD and COD:N were used to evaluate the merit of candidate physical, chemical and biological treatment alternatives. COD fractionation was effected to assess biological treatability and to yield the necessary process components to the recent modelling approaches.