Hydro-geomorphological modelling of ash-fall pyroclastic soils for debris flow initiation and groundwater recharge in Campania (southern Italy)

Carbonate mountain ranges surrounding volcanic centers in the Campania region of southern Italy are covered by discontinuous ash-fall pyroclastic deposits of variable thicknesses. The cover thickness and stratigraphy are relevant to hydrological controls on both rainfall-induced landslides and groundwater recharge. To improve understanding of the hydrologic regimes within the pyroclastic soil mantle, a hydrological monitoring station was installed upslope of a debris flow source area in the Sarno Mountains. Monitoring results demonstrate consistently unsaturated conditions, strong seasonal and inter-annual variations in pressure head, and delayed and damped dynamics at different depths related to rainfall and evapotranspiration patterns. Frequencies of recorded pressure head time series were analyzed to quantify the seasonal hydrological regime of the cover as a whole, as well as variations within individual soil horizons. For the whole ash-fall pyroclastic soil cover, variable seasonal frequencies of pressure head were recognized exceeding landslide alert and groundwater recharge threshold values. Analysis of frequencies for individual soil horizons showed a strongly delayed timing determining in winter and summer an opposite hydrological behavior between the shallowest and deepest soil horizons. A model that accounts for topographic variations in cover thickness and these hydrological regimes is proposed to quantify hydro-geomorphological controls on debris flows triggering and groundwater recharge. The model is based on the estimation of ash-fall pyroclastic soil thickness along slopes by the total thickness fallen in a given area and an inverse relationship with slope angle, allowing the assessment at the distributed scale over peri-volcanic mountainous areas. Moreover, it links the spatially variable thicknesses of ash-fall pyroclastic soils to the amount of soil water storage allowing the assessment of frequency of hydrological conditions leading to debris flow initiation and groundwater recharge

Word Length Perturbations in Certain Symmetric Presentations of Dihedral Groups

Given a finite group with a generating subset there is a well-established notion of length for a group element given in terms of its minimal length expression as a product of elements from the generating set. Recently, certain quantities called $\lambda_{1}$ and $\lambda_{2}$ have been defined that allow for a precise measure of how stable a group is under certain types of small perturbations in the generating expressions for the elements of the group. These quantities provide a means to measure differences among all possible paths in a Cayley graph for a group, establish a group theoretic analog for the notion of stability in nonlinear dynamical systems, and play an important role in the application of groups to computational genomics. In this paper, we further expose the fundamental properties of $\lambda_{1}$ and $\lambda_{2}$ by establishing their bounds when the underlying group is a dihedral group. An essential step in our approach is to completely characterize so-called symmetric presentations of the dihedral groups, providing insight into the manner in which $\lambda_{1}$ and $\lambda_{2}$ interact with finite group presentations. This is of interest independent of the study of the quantities $\lambda_{1},\; \lambda_{2}$. Finally, we discuss several conjectures and open questions for future consideration

Estimating annual groundwater recharge coefficient for karst aquifers of the southern Apennines (Italy)

Abstract. To assess the mean annual groundwater recharge of the karst aquifers in the southern Apennines (Italy), the estimation of the mean annual groundwater recharge coefficient (AGRC) was conducted by means of an integrated approach based on hydrogeological, hydrological, geomorphological, land use and soil cover analyses. Starting from the hydrological budget equation, the coefficient was conceived as the ratio between the net groundwater outflow and the precipitation minus actual evapotranspiration (P − ETR) for a karst aquifer. A large part of the southern Apennines, which is covered by a meteorological network containing 40 principal karst aquifers, was studied. Using precipitation and air temperature time series gathered through monitoring stations operating in the period 1926–2012, the mean annual P − ETR was estimated, and its distribution was modelled at a regional scale by considering the orographic barrier and rain shadow effects of the Apennine chain, as well as the altitudinal control. Four sample karst aquifers with available long spring discharge time series were identified for estimating the AGRC. The resulting values were correlated with other parameters that control groundwater recharge, such as the extension of outcropping karst rocks, morphological settings, land use and covering soil type. A multiple linear regression between the AGRC, lithology and the summit plateau and endorheic areas was found. This empirical model was used to assess the AGRC and mean annual groundwater recharge in other regional karst aquifers. The coefficient was calculated as ranging between 50 and 79%, thus being comparable with other similar estimations carried out for karst aquifers of European and Mediterranean countries. The mean annual groundwater recharge for karst aquifers of the southern Apennines was assessed by these characterizations and validated by a comparison with available groundwater outflow measurements. These results represent a deeper understanding of an aspect of groundwater hydrology in karst aquifers which is fundamental for the formulation of appropriate management models of groundwater resources at a regional scale, also taking into account mitigation strategies for climate change impacts. Finally, the proposed hydrological characterizations are also supposed to be useful for the assessment of mean annual runoff over carbonate mountains, which is another important topic concerning water management in the southern Apennines

Oral malodor in Special Care Patients: current knowledge

Epidemiological studies report that about 50% of the population may have oral malodor with a strong social and psychological impact in their daily life. When intra-oral causes are excluded, referral to an appropriate medical specialist is paramount for management and treatment of extra-oral causes. The intra-oral causes of halitosis are highly common, and the dentist is the central clinician to diagnose and treat them. Pseudohalitosis or halitophobia may occur and an early identification of these conditions by the dentist is important in order to avoid unnecessary dental treatments for patients who need psychological or psychiatric therapy. The organoleptic technique is still considered the most reliable examination method to diagnose genuine halitosis. Special needs patients are more prone than others to have oral malodor because of concurrent systemic or metabolic diseases, and medications. The present report reviews halitosis, its implications, and the management in special care dentistry

Coupled decadal variability of the North Atlantic Oscillation, regional rainfall and karst spring discharges in the Campania region (southern Italy)

Abstract. Thus far, studies on climate change have focused mainly on the variability of the atmospheric and surface components of the hydrologic cycle, investigating the impact of this variability on the environment, especially with respect to the risks of desertification, droughts and floods. Conversely, the impacts of climate change on the recharge of aquifers and on the variability of groundwater flow have been less investigated, especially in Mediterranean karst areas whose water supply systems depend heavily upon groundwater exploitation. In this paper, long-term climatic variability and its influence on groundwater recharge were analysed by examining decadal patterns of precipitation, air temperature and spring discharges in the Campania region (southern Italy), coupled with the North Atlantic Oscillation (NAO). The time series of precipitation and air temperature were gathered over 90 yr, from 1921 to 2010, using 18 rain gauges and 9 air temperature stations with the most continuous functioning. The time series of the winter NAO index and of the discharges of 3 karst springs, selected from those feeding the major aqueducts systems, were collected for the same period. Regional normalised indexes of the precipitation, air temperature and karst spring discharges were calculated, and different methods were applied to analyse the related time series, including long-term trend analysis using smoothing numerical techniques, cross-correlation and Fourier analysis. The investigation of the normalised indexes highlighted the existence of long-term complex periodicities, from 2 to more than 30 yr, with differences in average values of up to approximately ±30% for precipitation and karst spring discharges, which were both strongly correlated with the winter NAO index. Although the effects of the North Atlantic Oscillation (NAO) had already been demonstrated in the long-term precipitation and streamflow patterns of different European countries and Mediterranean areas, the results of this study allow for the establishment of a link between a large-scale atmospheric cycle and the groundwater recharge of carbonate karst aquifers. Consequently, the winter NAO index could also be considered as a proxy to forecast the decadal variability of groundwater flow in Mediterranean karst areas

Engineering geological 3D modeling and geotechnical characterization in the framework of technical rules for geotechnical design: the case study of the Nola’s logistic plant (southern Italy)

model is an essential step to optimize costs of the construction and limit risks from failure or damage due to unforeseen ground conditions. The modeling of ground conditions is a challenging issue to be tackled especially in the case of geological units with complex geometries and spatially variable geotechnical properties. In such a direction, coupled geological and geotechnical criteria are usually adopted to define engineering geological units. These concepts are considered by the current technical rules for geotechnical design such as the Eurocode 7 and in the national regulations which have followed it, known in Italy as “Norme Tecniche per le Costruzioni (NTC).” Notwithstanding this advanced regulatory framework, no comprehensive indications on methodological approaches were given for the 3D engineering geological modeling and geotechnical characterization of a design and construction site. In this paper, the case study of the highly heterogeneous and heteropic pyroclastic-alluvial stratigraphic setting of the Nola plain (Campania, southern Italy) characterizing the site of the Nola’s logistic plant is dealt with. The approaches are based on the engineering geological modeling analysis of a high number of stratigraphic, laboratory and in situ geotechnical data, collected for the design of the plant, and the use of a specialized modeling software providing advanced capabilities in spatial modeling of geological and geotechnical information, as well as in their visual representation. The results obtained, including also the analysis of statistical variability of geotechnical properties and the identification of representative geotechnical values, can be potentially considered a methodological approach, consistent with the current technical rules for geotechnical design as well as with fundamental concepts of engineering geological modeling and mapping

Testing evapotranspiration estimates based on MODIS satellite data in the assessment of the groundwater recharge of karst aquifers in southern Italy

In many Italian regions, and particularly in southern Italy, karst aquifers are the main sources of drinking water and play a crucial role in the socio-economic development of the territory. Hence, estimating the groundwater recharge of these aquifers is a fundamental task for the proper management of water resources, while also considering the impacts of climate changes. In the southern Apennines, the assessment of hydrological parameters that is needed for the estimation of groundwater recharge is a challenging issue, especially for the spatial and temporal inhomogeneity of networks of rain and air temperature stations, as well as the variable geomorphological features and land use across mountainous karst areas. In such a framework, the integration of terrestrial and remotely sensed data is a promising approach to limit these uncertainties. In this research, estimations of actual evapotranspiration and groundwater recharge using remotely sensed data gathered by the Moderate Resolution Imaging Spectrometer (MODIS) satellite in the period 2000–2014 are shown for karst aquifers of the southern Apennines. To assess the uncertainties affecting conventional methods based on empirical formulas, the values estimated by the MODIS dataset were compared with those calculated by Coutagne, Turc, and Thornthwaite classical empirical formulas, which were based on the recordings of meteorological stations. The annual rainfall time series of 266 rain gauges and 150 air temperature stations, recorded using meteorological networks managed by public agencies in the period 2000–2014, were considered for reconstructing the regional distributed models of actual evapotranspiration (AET) and groundwater recharge. Considering the MODIS AET, the mean annual groundwater recharge for karst aquifers was estimated to be about 448 mm·year−1 . In contrast, using the Turc, Coutagne, and Thornthwaite methods, it was estimated as being 494, 533, and 437 mm·year−1, respectively. The obtained results open a new methodological perspective for the assessment of the groundwater recharge of karst aquifers at the regional and mean annual scales, allowing for limiting uncertainties and taking into account a spatial resolution greater than that of the existing meteorological networks. Among the most relevant results obtained via the comparison of classical approaches used for estimating evapotranspiration is the good matching of the actual evapotranspiration estimated using MODIS data with the potential evapotranspiration estimated using the Thornthwaite formula. This result was considered linked to the availability of soil moisture for the evapotranspiration demand due to the relevant precipitation in the area, the general occurrence of soils covering karst aquifers, and the dense vegetation

Groundwater vulnerability of principal aquifers of the Campania region (southern Italy)

The assessment of groundwater vulnerability is an important aspect of territorial planning aimed at the management and protection of groundwater quality. This topic is particularly relevant for the Campania region (southern Italy) due to the abundance of groundwater resources and the strong dependence on them of current economic, social and environmental settings. The region is characterized by complex geological, structural and hydrogeological frameworks which make challenging and innovative the assessment of groundwater vulnerability with SINTACS, a parametric method officially recognized by the Italian environmental agencies. In order to apply results obtained to current regional regulations, groundwater vulnerability was estimated for the 80 principal aquifers, hosting respective groundwater bodies, as recognized by the application of the Directive 2000/60/EC. Among principal results, the alluvial and limestone (karst) aquifers, which are the most productive of the region, show the highest groundwater vulnerability, even with spatially variable conditions depending on local hydrogeological features

A comparison of methods for assessing groundwater vulnerability in karst aquifers: the case study of Terminio Mt. aquifer (Southern Italy)

The assessment of groundwater vulnerability to pollution is becoming even more important all over the world due to the increase of impacts of human activities on groundwater resources and the related risks to the human health, economics, and the environment. Owing to the variability of methods known for estimating groundwater vulnerability, basically depending on hydrogeological parameters considered and the scale of analysis, the comparison of results of different methods appears straightforward for identifying the best approach in a given hydrogeological condition and reference scale. In such a view, this work attempts to assess the groundwater vulnerability of the Terminio Mt. karst aquifer, by applying four different groundwater vulnerability methods, index-based, and comparing results in order to identify the best performing one in karst environments. The study aquifer, located in the Picentini Mts Regional Park (Campania region, southern Italy) represents a strategic drinking water resource since Roman times and hosts massive groundwater resources which outflow mainly from tapped basal and subordinately perched springs. The peculiar characters of the study karst aquifer, which favour direct infiltration and groundwater recharge processes, as well as the occurrence of industrial, agricultural and grazing activities, make it very vulnerable to groundwater pollution, thus requiring a proper and careful territorial management. Beside the most frequently and generally used methods for assessing groundwater vulnerability, such as the DRASTIC and SINTACS, also DAC and COP methods specifically designed for karst aquifers were applied and mutually compared. Results of SINTACS, DRASTIC and DAC methods show groundwater vulnerability maps of the Terminio Mt. karst aquifer as chiefly characterized by two classes of intrinsic groundwater vulnerability, varying between the medium and high degrees. Furthermore, high and extremely high values of groundwater vulnerability were found in areas controlled by the shallow depth of the water-table. Instead, the COP method resulted as the most effective in identifying the endorheic areas and the related karst morphologies as very high groundwater vulnerability zones, therefore the most suitable in capturing specific hydrogeological features of karst areas that control groundwater pollution and vulnerability. Results obtained will support decision tools aimed at the land use planning and protection of karst aquifers from pollution in karst areas

Effectiveness and compliance of an oscillating-rotating toothbrush in patients with dental implants: a randomized clinical trial

BackgroundThe aim of this randomized clinical trial was to assess the efficacy of an oscillating-rotating toothbrush in reducing plaque and inflammation around dental implants.MethodsEighty patients presenting dental implants were enrolled in this study and assigned randomly to two different groups: 40 patients in the test group and 40 in the control one. Each patient in the test group received an oscillating-rotating toothbrush while in the control group patients kept using the manual toothbrush. Furthermore, the test group received a special toothbrush head designed for dental implants and another one for natural teeth. Domiciliary oral hygiene instructions were given to both groups. Periodontal parameters like plaque index (PI), bleeding on probing (BoP), and probing pocket depth (PPD) were recorded at the baseline and after 1 and 3months.ResultsAt the end of the study, the difference of plaque and bleeding indices with the baseline was statistically significant for both test and control groups (P0.05). No significant differences were appreciated concerning the PPD.ConclusionsThe oscillating-rotating toothbrush can be successfully used for the plaque and bleeding control of the peri-implant tissues