Influence of threshold value in the use of statistical methods for groundwater vulnerability assessment

Statistical techniques can be used in groundwater pollution problems to determine the relationships among observed contamination (impacted wells representing an occurrence of what has to be predicted), environmental factors that may influence it and the potential contamination sources. Determination of a threshold concentration to discriminate between impacted or non impacted wells represents a key issue in the application of these techniques. In this work the effects on groundwater vulnerability assessment by statistical methods due to the use of different threshold values have been evaluated. The study area (Province of Milan, northern Italy) is about 2000 km² and groundwater nitrate concentration is constantly monitored by a net of about 300 wells. Along with different predictor factors three different threshold values of nitrate concentration have been considered to perform the vulnerability assessment of the shallow unconfined aquifer. The likelihood ratio model has been chosen to analyze the spatial distribution of the vulnerable areas. The reliability of the three final vulnerability maps has been tested showing that all maps identify a general positive trend relating mean nitrate concentration in the wells and vulnerability classes the same wells belong to. Then using the kappa coefficient the influence of the different threshold values has been evaluated comparing the spatial distribution of the resulting vulnerability classes in each map. The use of different threshold does not determine different vulnerability assessment if results are analyzed on a broad scale, even if the smaller threshold value gives the poorest performance in terms of reliability. On the contrary, the spatial distribution of a detailed vulnerability assessment is strongly influenced by the selected threshold used to identify the occurrences, suggesting that there is a strong relationship among the number of identified occurrences, the scale of the maps representing the predictor factors and the model efficiency in discriminating different vulnerable areas.     

Außenwandkonstruktionen für Schwimmhallen

Die kontinuierlich steigenden Anforderungen an die allgemeinen Komfortbedingungen in Verbindung mit einer immer weiter wachsenden Nachfrage nach den unterschiedlichsten Wellness‐Angeboten führen sowohl im Hotel‐ und Touristikgewerbe als auch im privaten Bereich zu umfangreichen Neu‐ und Umbaumaßnahmen. Bei öffentlichen Schwimmhallen liegt das Hauptaugenmerk dabei auf geeigneten Maßnahmen zur Steigerung der Energie‐Effizienz bei gleichzeitiger Modernisierung und Attraktivierung der entsprechenden Gebäudeteile. Nun handelt es sich bei diesen Gebäuden oder Gebäudeteilen um bauliche Einrichtungen, deren Nutzung beispielsweise als Schwimmhalle, als Whirlpoolraum oder als Saunavorraum eine gegenüber den konventionellen Randbedingungen von Aufenthaltsräumen deutlich erhöhte Feuchtebelastung bedingt: Es liegen hier nicht nur gegenüber Wohngebäuden deutlich erhöhte Temperaturen und Luftfeuchten – und damit eine völlig andere Größenordnung der Wasserdampfpartialdrücke der Raumluft – sondern auch grundsätzlich andere Nutzungs‐ und Betriebszeiten vor. Damit ergibt sich dann, dass der dauerhaft schaden‐ und mängelfreie Betrieb einer solchen Einrichtung eine entsprechend angepasste Baukonstruktion der umgebenden Bauteile und somit eine spezielle fachliche Betrachtung der bauphysikalischen Randbedingungen erfordert. Während für die konventionelle Wohn‐ oder Büronutzung eines Gebäudes die bauklimatisch anzusetzenden Randbedingungen (sowie die korrespondierenden Nachweisverfahren) normativ geregelt sind und die Auswirkungen auf die entsprechende bauliche Realisierung damit mehr oder weniger geläufig sind, fehlen diese Erkenntnisse im Bereich der Feuchträume im Allgemeinen und der Schwimmhallen im Besonderen weitestgehend. External wall constructions for indoor swimming pools. The continually increasing requirements for general comfort conditions combined with an ever growing demand for the widest range of wellness facilities result in numerous new‐build and extension projects in the hotel and tourist trade as well as in private homes (example see fig. 1). With public swimming pools the focus of attention is on suitable measures to increase the energy efficiency of the relevant parts of buildings and to modernise and make them more attractive at the same time. With these buildings or parts of buildings we are dealing with buildings used as swimming pools, jacuzzis or saunas and much more exposed to the effects of moisture compared to the normal boundary conditions of recreational areas: Not only are the temperatures and humidity content much higher and therefore the partial pressures of the water vapour in the air indoors on a completely different scale, but they are generally open and used at different times. This means that the long‐term operation of such a building free of damage and shortcomings requires a correspondingly suitable construction of the surrounding components and thus a special expert assessment of the building physics boundary conditions. Whereas the boundary conditions relating to the temperature and moisture in the building (and the corresponding methods) to be applied to residential or office buildings are regulated by standards and the effects on the corresponding construction of the building in practice are therefore more or less familiar, there is a general lack of this information for indoor areas with high humidity in general and swimming pools in particular.     

Occurrence of major and trace elements in powdered milk from Argentina

The concentrations of major and trace elements in Argentinean commercial powdered milk samples were determined with inductively coupled plasma mass spectrometry. Also the daily intake (DI) was calculated for adults and infants. The concentrations of B, Mg, Na, K and Ca were significantly higher in skimmed milk. Cu, Mo, Fe, Mn and Zn were significantly higher in infant formula. All the DIs were below the tolerable upper intake levels. The mean As concentration (26.0 ± 8.6 ng/g) in the powdered skimmed milk samples was slightly higher than in the others. Mean Pb concentrations ranged from 4.1 ± 2.1 to 13.5 ± 8.2 ng/g. The highest mean U concentration was 7.8 ± 2.6 ng/g for whole milk. This study contributes to the knowledge of major and trace elements in powdered milk and its contribution to the diet in Argentina.     

Peptides from water buffalo cheese whey induced senescence cell death via ceramide secretion in human colon adenocarcinoma cell line

Scope: Milk proteins are a source of bioactive peptides. Recent studies have indicated that protein‐derived peptides released in buffalo cheese acid whey exert a cytomodulatory effect in human epithelial colon cancer (CaCo2) cells. The aim of the present study was to explain the molecular mechanism involved in the response of CaCo2 cells to oxidative stress in the presence of peptide fractions of buffalo cheese whey, purified and characterized by mass spectrometry. Methods and results: We demonstrated that treatment of CaCo2 treated with H₂O₂ (H‐CaCo2) cells with a partially purified peptide sub‐fraction (f3) from buffalo cheese acid whey induced a reduction of mitochondrial superoxide anion with subsequent decrease in heat shock protein 70 and 90 expression. Moreover, we observed a 5‐fold decrease in cyclin A expression and cell cycle arrest in G1/G0 phases. These responses were associated with increased activity of alkaline phosphatase and beta‐galactosidase, markers of differentiation and senescence respectively. Conclusions: The structural characterization of the active peptide fraction and the elucidation of the effects induced by its treatment on H‐CaCo2 cells in vitro demonstrated an activity of this peptide sub‐fraction in the modulation of cell cycle, thus suggesting potential application for the development of nutraceuticals as well as health‐promoting functional foods.     

Property specification patterns at work: verification and inconsistency explanation

Innovations in Systems and Software Engineering - Property specification patterns (PSPs) have been proposed to ease the formalization of requirements, yet enable automated verification thereof. In...     

The influence of vehicle front-end design on pedestrian ground impact

Accident data have shown that in pedestrian accidents with high-fronted vehicles (SUVs and vans) the risk of pedestrian head injuries from the contact with the ground is higher than with low-fronted vehicles (passenger cars). However, the reasons for this remain poorly understood. This paper addresses this question using multibody modelling to investigate the influence of vehicle front height and shape in pedestrian accidents on the mechanism of impact with the ground and on head ground impact speed. To this end, a set of 648 pedestrian/vehicle crash simulations was carried out using the MADYMO multibody simulation software. Impacts were simulated with six vehicle types at three impact speeds (20, 30, 40 km/h) and three pedestrian types (50th % male, 5th % female, and 6-year-old child) at six different initial stance configurations, stationary and walking at 1.4 m/s.     

Coded transmissions for space links affected by solar scintillation: Baseband analysis

A thorough analysis of the behavior of error‐correcting codes over space links affected by solar scintillation is presented. The relevant channel parameters are fixed through the development of a model based on real missions' data. Both telecommand and telemetry links are considered in fast and slow fading conditions. Besides classical coherent modulation schemes, the possibility to use noncoherent modulation schemes is considered, to eliminate the problem of phase tracking. For the case of channels with very slow fading, the use of external interleavers or erasure coding is proposed to cope with error bursts.