11 research outputs found
Variabilit? naturale e legata a fattori antropici nei siti lacustri studiati
The natural variability of the biotic components, in particular of those showing seasonal cycles, often leads to significant changes of biomass as well as specific composition. This means that the choice of sampling frequency and distribution during the year may be crucial when assessing the ecological quality of a waterbody, starting from the structure of biotic communities. Among the four biological quality elements used to classify the lakes, three of them (phytoplankton, macrophytes and macroinvertebrates) show a marked seasonality and/or a certain degree of spatial variability. This document has the aim to evaluate how the metrics used are sensitive to the natural variability, especially respect to their response to the pressure gradients. The analysis was carried out on data collected during the project and is limited to phytoplankton and macrophytes, because the examination of autumn samples of macroinvertebrates, is still in progress. Regarding phytoplankton, three metrics defined by Italian national legislation (composition indices, chlorophyll and biovolume) were analyzed, comparing the variability due to anthropogenic origin (expressed by the gradient of total phosphorus) with the natural one (seasonal variations on different time scales) and estimating the uncertainty in the classification using different sampling frequencies. In the case of macrophytes, monitoring methods and classification were analyzed respect to their accuracy in assessing if the variability between sites, explained by a different anthropogenic pressure, is actually greater than the variance within the individual lake. In addition, we want to determine if the sampling effort, as established by the monitoring protocols, is adequate to the needs of the classification. Our analysis showed that the variability of phytoplankton metrics reflects the trophic gradient and is more significant than that explained by seasonal fluctuations, demonstrating the robustness of the indicators used. Moreover, the phytoplankton assemblages reveal a high stability in interannual patterns of succession. Conversely, the general formulation of the macrophytic index may need to be redefined to better understand the differences in ecological quality between lakes. Furthermore, as concerns macrophytes, a significant reduction of the sampling effort does not seem to be possible without compromising the quality of classification, while, as regards phytoplankton, it would be acceptable to reduce the number of annual samples from 6 to 4 without compromising the result of the classification, while observing the seasonality, because our analysis suggests that phytoplankton samples concentrated in a single season lead to increased uncertainty in the classification.La variabilit? naturale delle componenti biotiche, in modo particolare di quelle che mostrano cicli su base stagionale, porta a cambiamenti spesso significativi della composizione specifica e della biomassa. Questo significa che la scelta della frequenza di campionamento e la distribuzione dei prelievi nel corso dell\u27anno possono rappresentare dei fattori critici quando si tratta di valutare la qualit? ecologica a partire dalla struttura delle comunit? biotiche. Delle quattro componenti biologiche usate per classificare i laghi, tre (fitoplancton, macrofite e macroinvertebrati) mostrano una spiccata stagionalit? e/o una certa variabilit? spaziale. Il presente documento ? stato redatto con lo scopo di valutare quanto le metriche utilizzate siano sensibili alla variabilit? di origine naturale, soprattutto in relazione alla loro risposta rispetto ai gradienti di pressione. L?analisi ? stata condotta sui dati raccolti nel corso del progetto ed ? limitata al fitoplancton ed alle macrofite, poich? l?esame dei campioni autunnali dei macroinvertebrati ? tuttora in corso. Per quanto riguarda il fitoplancton sono state analizzate tre metriche indicate dalla normativa nazionale (indici di composizione, clorofilla e biovolume), confrontandone la variabilit? di origine antropica (espressa dal gradiente di fosforo totale) con quella naturale (stagionalit? su diverse scale temporali) e stimando l?incertezza nella classificazione con frequenze di prelievo diverse. Nel caso delle macrofite, i metodi di monitoraggio e di classificazione sono stati analizzati rispetto alla loro accuratezza nel valutare se la variabilit? tra ambienti, dovuta alla diversa pressione antropica, sia effettivamente maggiore rispetto alla varianza all?interno del singolo lago. Inoltre, si vuole valutare se lo sforzo di campionamento, previsto dai protocolli di monitoraggio, sia adeguato alle esigenze della classificazione. La nostra analisi ha messo in evidenza che la variabilit? delle metriche fitoplanctoniche rispecchia il gradiente trofico ed ? pi? significativa rispetto a quella spiegata dalle fluttuazioni stagionali, dimostrando la robustezza degli indicatori utilizzati e che le associazioni fitoplanctoniche rilevano un grande stabilit? negli schemi di successione interannuali. Viceversa, la formulazione generale dell?indice macrofitico potrebbe necessitare di una ridefinizione per meglio cogliere le differenze di qualit? ecologica tra i laghi. Inoltre, nel caso delle macrofite, una riduzione significativa dello sforzo di campionamento non pare possibile senza compromettere la qualit? della classificazione, mentre, per quanto riguarda il fitoplancton, sarebbe accettabile ridurre il numero dei prelievi annuali da 6 a 4 senza compromettere il risultato della classificazione, rispettando comunque la stagionalit?, poich? prelievi di fitoplancton concentrati in una sola stagione determinano una maggiore incertezza nella classificazione
Analisi della relazione tra le concentrazione di azoto e la composizione delle comunit? acquatiche
This report presents an analysis of the relationships between environmental variables and organisms belonging to the four biotic communities used to define the lake\u27s ecological quality, according to provisions of the Italian legislation (D.Lgs. 260, November 2010) and the European Water Framework 2000/6. The data analyzed were collected during the sampling surveys carried out within InHabit Project in 13 water bodies, 7 in Piedmont and 6 in Sardinia respectively. In particular, the aim of the study was to evaluate the possible effects of nitrogen on biotic communities. Phytoplankton community shown the clearer responses: according to the result of multivariate analysis, total nitrogen and ammonium nitrogen are among the most significant factors explaining the relationships among phytoplankton orders, species and environmental variables. In particular, cyanobacteria increased considerably with increasing availability of ammonium nitrogen. Conversely, high concentrations of this compound suppress the development of diatoms. Other algal groups show a nonlinear response with respect to nitrogen, with a possible limitation under low levels of nitrogen and an inhibition at higher levels. A comparative analysis, carried out to evaluate the response to the gradient of total phosphorus, shows that this nutrient is not as selective as nitrogen in controlling the structure of the algal assemblage in different environmental conditions. Other biotic communities did not show a clear relationship with nitrogen, but they rather responded to the trophic gradient as a whole: responses by macroinvertebrates seem, especially in the analysis of functional groups, complex and difficult to discriminate, highlighting a possible shifting of the food web towards the presence of large carnivores at high trophic status. Regarding the fish, the results show that nitrogen alone does not seem to be an important controlling factor for the fish communities. However together with the phosphorus, is one of the main elements controlling both biomass and size of the fish fauna, as well as the presence of tolerant, omnivorous or benthofagous species. In conclusion, the results of our analysis highlight the need for a greater emphasis on nitrogen inputs, which, especially in cases of nitrogen carried by atmospheric deposition, may even affect lake ecosystems relatively distant from direct impacts of human activities, thus altering the structure of biotic communities.A partire dai dati raccolti con le campagne di campionamento effettuate nell?ambito del progetto InHabit, questo documento presenta un?analisi delle relazioni tra le variabili ambientali e gli organismi appartenenti alle quattro comunit? biotiche utilizzate per la definizione della qualit? ecologica degli ambienti lacustri, secondo quanto previsto dal D.Lgs. 260 del novembre 2010, che recepisce la Direttiva Europea sulle Acque 2000/60. I campionamenti sono stati condotti in 13 ambienti lacustri, 7 in Piemonte e 6 in Sardegna. In particolare, lo scopo del lavoro ? stato valutare i possibili effetti sulla comunit? biotiche di concentrazioni variabili dei composti azotati inclusi tra le variabili considerate. La comunit? che mostra le risposte pi? chiare ? quella fitoplanctonica: come risulta dall?analisi multivariata, sia azoto ammoniacale che azoto totale compaiono tra le variabili significative per spiegare l?ordinamento di ordini e specie fitoplanctoniche. Tra questi, sono soprattutto i cianobatteri che aumentano sensibilmente all?aumentare della disponibilit? di azoto ammonicale. Al contrario, elevate concentrazioni di questo composto deprimono lo sviluppo delle diatomee. Altri gruppi algali mostrano una risposta non lineare rispetto ai composti azotati, con una possibile limitazione a bassi livelli di azoto ed una inibizione a livelli troppo elevati. L?analisi della risposta rispetto al gradiente di fosforo totale, mostra che questo nutriente non ? selettivo come l?azoto nel controllare la struttura delle associazioni algali in diverse condizioni ambientali. Le altre comunit? non hanno mostrato una relazione evidente con i composti azotati, ma, piuttosto, con il gradiente trofico complessivo: le risposte evidenziate dalla fauna macroinvertebrata, sembrano, soprattutto nell?analisi dei gruppi funzionali, complesse e difficili da discriminare, evidenziando un possibile spostamento degli equilibri della rete trofica verso i carnivori in presenza di elevati livelli trofici. Relativamente alla fauna ittica, i risultati mostrano che da solo l?azoto non sembra essere un fattore di controllo importante per la comunit? ittiche. Tuttavia insieme al fosforo, ? uno degli elementi principali a cui si associano positivamente la biomassa e le dimensioni della fauna ittica, nonch? la presenza di specie tolleranti, onnivore o bentofaghe. In conclusione, i risultati della nostra analisi, sottolineano ulteriormente la necessit? di porre una maggiore attenzione agli apporti di azoto, che, soprattutto nei casi di azoto veicolato da deposizioni atmosferiche, potrebbero interessare anche ecosistemi lacustri relativamente distanti da impatti diretti delle attivit? antropiche, alterandone la struttura delle comunit? biotiche
Effetti dell\u27inquinamento da azoto nei laghi e nei fiumi e suggerimento per il miglioramento dei PdG
This report summarizes the finding of the InHabit project on the importance of atmospheric nitrogen deposition in affecting the chemical composition of lake water and in eventually altering the biological communities living in them. Previous deliverables (I2d5, Id26 and I2d7) have shown that; 1. in both regions studied in the InHabit project (Piedmont and Sardinia), atmospheric deposition of nitrogen compounds is relevant; 2. the flux of nitrogen from the atmosphere to the ecosystem is markedly larger in Piedmont than in Sardinia; 3. models of the dynamic behavior of nitrogen in forested catchments indicates that Piedmon soils are mainly N-saturated, so that nitrogen carried by atmospheric deposition can be released form forest soil to the surface water; 4. in Sardinia, soil are less saturated, but a part of the deposited nitrogen is still carried to surface water; 5. trend analysis of deposition and stream water revealed that nitrogen deposition is stable or slightly decreasing in recent years, both in atmospheric deposition and in stream water; 6. the importance relative importance of N deposition is relevant for sites in or close to reference conditions; 7. the relationships between environmental variables and organisms belonging to the four biotic communities used to define the lake\u27s ecological quality, according to provisions of the Italian legislation (D.Lgs. 260, November 2010) and the European Water Framework 2000/60 differ depending on the biological quality element considered; 8. phytoplankton community shows the clearer responses: according to the result of multivariate analysis, total nitrogen and ammonium nitrogen are among the most significant factors explaining the relationships among phytoplankton orders, species and environmental variables. In particular, cyanobacteria increased considerably with increasing availability of ammonium nitrogen. Conversely, high concentrations of this compound suppress the development of diatoms. On the basis of those results, which are summarized in this deliverable, we focused on the effect of different levels of nitrogen in lakes with low phosphorus concentration, slightly affected by direct trophic pressure and close to the reference conditions. The comparison between two lakes in Piedmont with low P concentration and high N concentration with two reservoirs in Sardinia with low levels of both nutrients shows that the formers are dominated by diatoms and the latter by dynophytes. Two reservoirs in Piedmont with high N levels are also dominated by diatoms. In spite of the small number of lakes studied, it seems that dynophytes are more fitted to low N lakes, probably because of their ability to use an heterotrophic metabolism, while lakes in reference conditions are generally considered to be dominated by oligotrophic diatoms, Our findings call for deeper studies on reference conditions in the Mediterranean ecoregion, because they suggest that lakes not affected by direct trophic pressure, i.e. reference lakes, may host different diatom communities depending on the amount of nitrogen deposition they receive
Consistency of property estimators in distillation column control
This paper addresses the problem of input selection in inferential control of multicomponent distillation columns by introducing the concept of consistency. An estimator is consistent when a feedback (multivariable) control system that uses the estimates of the controlled variables guarantees low closed-loop steady-state offset in the true unmeasured controlled variables when disturbances enter the system (and/or set-point changes are considered). A definition of this property is given, and the relations between the estimator consistency and the closed-loop steady-state offset are derived for both single-input-single-output and multi-input-multioutput systems. A multicomponent distillation column case study is presented to show that the selection of the most "precise" inputs does not necessarily guarantee the lowest closed-loop offset in the presence of disturbances, whereas the use of less precise but more "consistent" inputs leads to a well-designed estimator that guarantees a lower closed-loop steady-state offset
How to Use Simplified Dynamics in Model Predictive Control of Superfractionators
In this paper, issues associated with the application of model predictive control algorithms to the product quality control of superfractionator columns are addressed. Full-order and reduced- order (pseudo-ramp) models are compared in different predictive control algorithms, and the effects of different disturbance models on the closed-loop performance are emphasized. The results show that the reduced-order model, which is easier to identify, can give excellent results when it is used along with an effective disturbance model and can be implemented with a relatively small sampling time. The results also show that the output disturbance model typically used by industrial algorithms, is the source of poor closed-loop performance, and although the input disturbance model represents a better choice, the rotation factor disturbance model used with the reduced model can represent a simple and relatively effective practical alternative
Reduction of plasma fibrinolytic activity following high-dose cyclophosphamide is neutralized in vivo by GM-CSF administration.
Use of Modified Functional Assays for Activated Protein C Resistance in Patients with Basally Prolonged aPTT
Banca dati delle informazioni biologiche e di qualit?. Parte 2: Laghi
A relational database was set up to host biological, chemical and hydromorphological data produced within the InHabit project. To avoid proprietary software or data format, we build the database using PostgreSQL, an Open Source Relational Database Management system. The data base contains information on lake water chemistry and the four biological quality elements quoted in the Annex V of the Directive 2000/60/EC (Water Framework Directive) for lakes: phytoplankton, macrophytes, benthic macroinvertebrates and fishes. The database was tested using the data collected within the InHabit project up to October 2011, but some data which are still awaiting improvement in taxonomic resolution or data validation will be uploaded to the database in the next months. At the moment, data on fishes, macrophytes and benthic macroinvertebrates are included for 2 lake and 6 reservoirs, 6 lakes and 7 reservoirs and 4 lakes and 3 reservoirs, respectively. In all cases they contain the full set of field data, but for benthic macroinvertebrates the taxonomic resolution can still be improved. Phytoplankton data are included up to the October 2011 sampling, as later samples are still being counted and data validated.Questo rapporto descrive la banca dati relazionale predisposta per i dati provenienti dai laghi all?interno del progetto InHabit. Per evitare l?uso di software proprietario, la banca dati ? stata allestita usando il software PostgreSQL, un gestore di database relazionali disponibile con licenza Open Source. La banca dati ? predisposta per contenere i dati relativi alla chimica delle acque e agli elementi di qualit? biologica previsti dalla Direttiva 2000/60/EC (Direttiva Quadro sulle Acque), e cio? fitoplancton, macrofite, fauna macrobentonica e pesci. La banca dati ? stata testata utilizzando i dati raccolti fino ad ottobre 2011, anche se alcuni dati di campagna sono ancora in fase di validazione o di approfondimento tassonomico e saranno quindi caricati nella banca dati nei prossimi mesi. Al momento di scrivere questo rapporto, la banca dati contiene i dati completi relativi alle macrofite, al macrobenthos e ai pesci rispettivamente per 7, 13 e 8 laghi, anche se nel caso del macrobenthos sono previsti ancora alcuni approfondimenti sistematici. Nel caso del fitoplancton, invece, i dati caricati nella banca dati si riferiscono solo ai primi mesi di campionamento, fino ad ottobre, in quanto per i rimanenti campioni devono ancora essere completati i conteggi e le procedure di validazione dei dati