Food security among dryland pastoralists and agropastoralists: The climate, land-use change, and population dynamics nexus

During the last decades, pastoralist, and agropastoralist populations of the world’s drylands have become exceedingly vulnerable to regional and global changes. Specifically, exacerbated stressors imposed on these populations have adversely affected their food security status, causing humanitarian emergencies and catastrophes. Of these stressors, climate variability and change, land-use and management practices, and dynamics of human demography are of a special importance. These factors affect all four pillars of food security, namely, food availability, access to food, food utilization, and food stability. The objective of this study was to critically review relevant literature to assess the complex web of interrelations and feedbacks that affect these factors. The increasing pressures on the world’s drylands necessitate a comprehensive analysis to advise policy makers regarding the complexity and linkages among factors, and to improve global action. The acquired insights may be the basis for alleviating food insecurity of vulnerable dryland populations.info:eu-repo/semantics/acceptedVersio

Study of PM10 and PM2.5 levels in three European cities: Analysis of intra and inter urban variations

In the present paper, 1-year PM10 and PM 2.5 data from roadside and urban background monitoring stations in Athens (Greece), Madrid (Spain) and London (UK) are analysed in relation to other air pollutants (NO,NO2,NOx,CO,O3 and SO2)and several meteorological parameters (wind velocity, temperature, relative humidity, precipitation, solar radiation and atmospheric pressure), in order to investigate the sources and factors affecting particulate pollution in large European cities. Principal component and regression analyses are therefore used to quantify the contribution of both combustion and non-combustion sources to the PM10 and PM 2.5 levels observed. The analysis reveals that the EU legislated PM 10 and PM2.5 limit values are frequently breached, forming a potential public health hazard in the areas studied. The seasonal variability patterns of particulates varies among cities and sites, with Athens and Madrid presenting higher PM10 concentrations during the warm period and suggesting the larger relative contribution of secondary and natural particles during hot and dry days. It is estimated that the contribution of non-combustion sources varies substantially among cities, sites and seasons and ranges between 38-67% and 40-62% in London, 26-50% and 20-62% in Athens, and 31-58% and 33-68% in Madrid, for both PM10 and PM 2.5. Higher contributions from non-combustion sources are found at urban background sites in all three cities, whereas in the traffic sites the seasonal differences are smaller. In addition, the non-combustion fraction of both particle metrics is higher during the warm season at all sites. On the whole, the analysis provides evidence of the substantial impact of non-combustion sources on local air quality in all three cities. While vehicular exhaust emissions carry a large part of the risk posed on human health by particle exposure, it is most likely that mitigation measures designed for their reduction will have a major effect only at traffic sites and additional measures will be necessary for the control of background levels. However, efforts in mitigation strategies should always focus on optimal health effects

Clustering and forecasting of dissolved oxygen concentration on a river basin

The aim of this contribution is to combine statistical methodologies to geographically classify homogeneous groups of water quality monitoring sites based on similarities in the temporal dynamics of the dissolved oxygen (DO) concentration, in order to obtain accurate forecasts of this quality variable. Our methodology intends to classify the water quality monitoring sites into spatial homogeneous groups, based on the DO concentration, which has been selected and considered relevant to characterize the water quality. We apply clustering techniques based on Kullback Information, measures that are obtained in the state space modelling process. For each homogeneous group of water quality monitoring sites we model the DO concentration using linear and state space models, which incorporate tendency and seasonality components in different ways. Both approaches are compared by the mean squared error (MSE) of forecasts

Estimation of PM10-bound As, Cd, Ni and Pb levels by means of statistical modelling: PLSR and ANN approaches

Air quality assessment regarding metals and metalloids using experimental measurements is expensive and time consuming due to the cost and time required for the analytical determination of the levels of these pollutants. According to the European Union (EU) Air Quality Framework Directive (Directive 2008/50/EC), other alternatives, such as objective estimation techniques, can be considered for ambient air quality assessment in zones and agglomerations where the level of pollutants is below a certain concentration value known as the lower assessment threshold. These conditions occur in urban areas in Cantabria (northern Spain). This work aims to estimate the levels of As, Cd, Ni and Pb in airborne PM10 at two urban sites in the Cantabria region (Castro Urdiales and Reinosa) using statistical models as objective estimation techniques. These models were developed based on three different approaches: partial least squares regression (PLSR), artificial neural networks (ANNs) and an alternative approach consisting of principal component analysis (PCA) coupled with ANNs (PCA-ANN). Additionally, these models were externally validated using previously unseen data. The results show that the models developed in this work based on PLSR and ANNs fulfil the EU uncertainty requirements for objective estimation techniques and provide an acceptable estimation of the mean values. As a consequence, they could be considered as an alternative to experimental measurements for air quality assessment regarding the aforementioned pollutants in the study areas while saving time and resources.The authors gratefully acknowledge the financial support from the Spanish Ministry of Economy and Competitiveness through the Project CMT2010-16068. The authors also thank the Regional Environment Ministry of the Cantabria Government for providing the PM10 samples at the Castro Urdiales and Reinosa sites

Study of side impact of manifold thin-walled tubular structures

66 σ.Η εργασία στοχεύει στη διερεύνηση της πλευρικής κατάρρευσης συστοιχιών κυλινδρικών μεταλλικών σωλήνων. Η βασική διάταξη / συστοιχία (ίδια διάταξη – διαφορετικές διαστάσεις) είναι η 2x2 (τέσσερις σωλήνες ανά δύο κάθετα διασταυρούμενοι). Για αυτή τη διάταξη διερευνήθηκε η επίδραση διαφορετικών διαστάσεων σωλήνων. Επιπλέον, επιλέχθηκε σωλήνας συγκεκριμένων διαστάσεων ώστε να διερευνηθεί περαιτέρω η συμπεριφορά σε αντίστοιχη (πλευρική) καταπόνηση όλων των δυνατών συνδυασμών διάταξης / συστοιχίας (ίδιες διαστάσεις – διαφορετική διάταξη) από έναν έως τέσσερις σωλήνες. Παράλληλα επιχειρήθηκε η μοντελοποίηση με τη μέθοδο των πεπερασμένων στοιχείων (κώδικας LS-DYNA) όλων των παραπάνω περιπτώσεων πλευρικής καταπόνησης προκειμένου να διερευνηθεί η δυνατότητα πρόβλεψης της συμπεριφοράς των συγκεκριμένων διατάξεων.This study aims at exploring the lateral collapse of tubular structures. The main structure is 2x2 (4 tubes; 2 tubes mounted perpendicular to the length of the other 2 tubes). The combination effect of tubes of different sizes has been examined for this structure. Moreover tubes of a specific size have been chosen in order to examine further the behavior after side impact. In this case structures from 1-4 tubes have been tested. At the same time modeling with LS-Dyna code has been used for all the above cases of lateral compression in order to predict the way these structures collapse.Φωτεινή Α. Πασχαλίδο

The relocation of heraclion international airport. A holistic environmental approach

The accelerated development of the touristic industry and consequently the increased touristic flows towards the greater area of the city of Heraklion in the island of Crete (Greece), as well as the needs of the increased local population and the related economic activities have introduced the necessity for a new, contemporary international airport. The existing "Nikos Kazantzakis" airport, located almost within the urban area, cannot serve the day-by-day increase of air traffic, while its infrastructures are rather outdated and its capacity limited. Recently a relocation program has been investigated, proposing a new site for the airport, at the area of Kasteli, located 37 Km southeast of the city. The new International Airport will be located in a rather rural environment, currently characterized by agricultural activities. The relocation will provide the rural area with a new, modern motorway network, connecting the new airport facilities with the city of Heraklion and the rest of the island. Furthermore, this relocation will reduce the levels of both air pollution and environmental noise in the urban area of Heraklion, while the expected levels of air pollution and environmental noise at Kasteli are expected to comply with the relevant EU limits. Since the nuisance to the people and the environment from big infrastructures cannot be isolated, this paper aims to present a holistic approach, covering both the positive and the negative effects that this relocation is expected to introduce in both areas

Zinc sorption by kaolinite: Influence of pH, electrolyte, and initial Zn concentrations with simultaneous release of Mg, Ca, Mn, and Cu ions

The present study deals with: (a)The influence of pH values, different electrolyte concentrations (ionic strength) and different initial Zn concentrations on Zn sorption by kaolinite, (b)The possible fit of sorption data to known sorption isotherms. (Langmuir, Freundlich, Tempkin and Sposito), and (c) The simultaneous release of other ions (Mg, Ca, Mn, and Cu) as a result of Zn sorption by Kaolinite and its possible implications. Experiments were carried out by using five different initial Zn concentrations (from 4.05 X 10(-5) to 5.17 X 10(-4)), two different electrolyte concentrations (10(-3) and 10(-2) M KNO3) and different pH values (3.5 to 8.5). The results, in general, show an increase of Zn sorption as pH and initial Zn concentrations increase, with simultaneous decrease in electrolyte concentration. Langmuir equation was found to describe Zn sorption data better at pH 4.5 and 7.5 in the presence of 10(-2) and 10(-3) M KNO3. Maximum Zn sorption was found to be 498 and 921 mg kg(-1) at pH 7.0, in the presence of 10-2 and 10-3 M KNO3 respectively. The other equations (Freundlich, Tempkin and Sposito) were found to describe better the Zn sorption data in the presence of 10(-2) M KNO3 and with less success in the presence of 10-3 M KNO3. At constant Zn initial concentration, as pH increased and molarity of electrolite decreased there was a decrease in the amount of Mg, Ca, Mn, and Cu released in a result of Zn sorption by kaolinite. When the initial concentration of Zn increases, at different pH values from 4.0 to 8.0 with constant KNO3 concentration (10(-3) M), there is an overall increase in ion concentration (Mg, Ca, Mn, and Cu). At 10(-2) M KNO3 and with different initial Zn concentrations and pH values as described before, the following were observed. Increase of Cu release at pH 5.5 to 6.5, decrease at pH 4.0 and 7.0 and no change at pH 8.0. Increase of Mn release at pH 4.0 to 6.0 and 8.0 decrease at 6.5 and no release at pH 7.0. Increase of Ca release at pH 4.0 to 6.5 and 8.0 and decrease at pH 7.0. Decrease of Mg release at all studied pH values. These observations should probably be taken into account when availability of these ions to plants is studied

On the association between synoptic circulation and wildfires in the Eastern Mediterranean

In the present paper cluster analysis of 2-month air mass back-trajectories for three contrasting fire and non-fire events is conducted (high, low, and zero burnt area). The large fire event displays an air mass history dissimilar to other events whereby a 39-day period of warm and dry chiefly northerly anticyclonic conditions is evident, before a week of warmer predominantly southwesterly cyclonic activity, immediately prior to ignition. The pressure level of these anticyclonic air masses is above 800 hPa for more than 75 % of the trajectory length; this region is above the principal moisture transport regime of 800 hPa altitude. Analysis of variance on the mean rate of change of potential temperature identified weak statistically significant differences between two air mass pairs regarding the large fire: anticyclonic and cyclonic air masses in both cases (p = 0.038 and p = 0.020). Such regularity of type and occurrence, approach pressure levels and statistically significant differences are not evident for the small and non-fire event air masses. Such understanding is expected to permit appropriate steps to be undertaken including superior prediction and improved suppression strategy