1,721,002 research outputs found
Algae as biomarkers, bioaccumulators and toxin producers
No full textUncontrolled accumulation of wastes in marine environments involves an increase in organic substances and/or nutrients, as well as toxicity. The consequences of this enrichment for the homeostasis of ecosystems are unpredictable. The best studied consequence of such enrichment is eutrophication (Conti, 1996). Natural or anthropogenic eutrophication is the enrichment of a water body in nutrients, utilizable by algae. Sources of these nutrients are the atmosphere, rivers, soil erosion and runoff from catchment areas, sewage, industrial effluents, fertilizers, and waste disposal from animal farms. Mathematical models predicting pollutant dispersion and pollutant bioavaibility may make a substantial contribution to the study of the marine pollution phenomena and may be a valuable tool for the description of the pollution flux (Benedini and Cicioni, 1992). Generally, mathematical models refer to the propagation and transport of particular pollutants originating from one-point contamination sources and also in this case need a broad spectrum of experimental data. This requirement is particularly true for sea ecosystems, owing to the large number of required variables and to the various effects on different species and ecosystems. For these reasons, biomonitoring programmes in sea environments are very important. Establishing the pollutant level in organisms may help to evaluate the possible toxicity for various species at different levels of the trophic chain
Variabilità di parametri di qualità microbiologica in schemi idrici scarsamente protetti
No full textassunto un grande interesse. Grandi investimenti vengono fatti in questo campo dai paesi membri della comunità europea e le più recenti normative, in particolare indirizzate a regolamentare i sistemi che distribuiscono acqua mediante reti idriche, spingono verso la costituzione di sistemi di gestione ad elevata qualità ambientale i quali vengono valutati principalmente dall’esame dell’acqua consegnata all’utenza.
Il presente articolo, sulla base dei riscontri teorici rilevati nella bibliografia scientifica esaminata, illustra i risultati di un’indagine condotta sugli impianti di uno schema idrico del Lazio mediante l’elaborazione dei dati raccolti durante un biennio di attività di monitoraggio della qualità delle acque trasportate nelle condotte e relativi ad un numero limitato di parametri microbiologici (coliformi e batteri eterotrofi). Questo studio segue una precedente indagine che ha riguardato l’analisi del processo di consumo di cloro libero nello stesso schema
Note tecnique sur la déterminations de la qualité sanitaire des bivalves comméstibles.
No full textIndagine conoscitiva sulla variabilità della qualità delle acque in schemi idrici scarsamente protetti
No full textSTUDIO DELLE POPOLAZIONI BATTERICHE E FITOPLANCTONICHE IN AREE MARINE COSTIERE RICEVENTI SCARICHI FOGNAI TRATTATI.
No full textSOME FEATURES OF A BLOOM OF OSCILLATORIA-RUBESCENS DC REGISTERED IN 2 ITALIAN RESERVOIRS
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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