Landscape changes and environmental quality: the evolution of land vulnerability and potential resilience to degradation in Italy

Resilience, considered as the ability of a system to absorb and compensate pressures derived from human and natural systems, is a topic of interest in the Mediterranean region whose landscape is the joint result of social, economic and environmental factors. The present study analyses the changes in the Italian landscape over two periods (1960–1990 and 1990–2010) of the last 50 years through a composite index of environmental resilience and vulnerability to land degradation. Results indicate that the spatial distribution of this index has been considerably changed from a relatively simple geography (mainly reflecting a latitude gradient) to a more complex pattern. The level of vulnerability of southern Italian land maintained quite stable while increasing significantly in Northern and Central Italy. The (potential) resilience level decreased over time in Central and Northern Italy while growing moderately in Southern Italy. This means that important processes of environmental changes impacting landscape resilience occurred with a different spatial trend in Italy. The composite index derived from vulnerability and potential resilience estimates at the regional scale revealed crucial to map over time the increase of surface land exposed to desertification risk. Results support the adoption of measures promoting a sustainable land management in environmentally vulnerable land with low potential to resilience.     

Explosibility of polyamide and polyester fibers

The current research is aimed at investigating the explosion behavior of hazardous materials in relation to aspects of particulate size. The materials of study are flocculent (fibrous) polyamide 6.6 (nylon) and polyester (polyethylene terephthalate). These materials may be termed nontraditional dusts due to their cylindrical shape which necessitates consideration of both particle diameter and length. The experimental work undertaken is divided into two main parts. The first deals with the determination of deflagration parameters for polyamide 6.6 (dtex 3.3) for different lengths: 0.3 mm, 0.5 mm, 0.75 mm, 0.9 mm and 1 mm; the second involves a study of the deflagration behavior of polyester and polyamide 6.6 samples, each having a length of 0.5 mm and two different values of dtex, namely 1.7 and 3.3. (Dtex or decitex is a unit of measure for the linear density of fibers. It is equivalent to the mass in grams per 10,000 m of a single filament, and can be converted to a particle diameter.) The explosibility parameters investigated for both flocculent materials include maximum explosion pressure (P_max), size-normalized maximum rate of pressure rise (K_St), minimum explosible concentration (MEC), minimum ignition energy (MIE) and minimum ignition temperature (MIT). ASTM protocols were followed using standard dust explosibility test equipment (Siwek 20-L explosion chamber, MIKE 3 apparatus and BAM oven). Both qualitative and quantitative analyses were undertaken as indicated by the following examples. Qualitative observation of the post-explosion residue for polyamide 6.6 indicated a complex interwoven structure, whereas the polyester residue showed a shiny, melt-type appearance. Quantitatively, the highest values of P_max and K_St were obtained at the shortest length and finest dtex for a given material. For a given length, polyester displayed a greater difference in P_max and K_St at different values of dtex than polyamide 6.6. Long ignition delay times were observed in the BAM oven (MIT measurements) for polyester, and video framing of explosions in the MIKE 3 apparatus (MIE measurements) enabled observation of secondary ignitions caused by flame propagation after the initial ignition occurring at the spark electrodes.     

A Parallel Graded-Mesh FDTD Algorithm for Human–Antenna Interaction Problems

The finite difference time domain method (FDTD) is frequently used for the numerical solution of a wide variety of electromagnetic (EM) problems and, among them, those concerning human exposure to EM fields. In many practical cases related to the assessment of occupational EM exposure, large simulation domains are modeled and high space resolution adopted, so that strong memory and central processing unit power requirements have to be satisfied. To better afford the computational effort, the use of parallel computing is a winning approach; alternatively, subgridding techniques are often implemented. However, the simultaneous use of subgridding schemes and parallel algorithms is very new. In this paper, an easy-to-implement and highly-efficient parallel graded-mesh (GM) FDTD scheme is proposed and applied to human–antenna interaction problems, demonstrating its appropriateness in dealing with complex occupational tasks and showing its capability to guarantee the advantages of a traditional subgridding technique without affecting the parallel FDTD performance.     

A study on the correlation between 13C/12C variations in tree rings and the growth pattern of trees

A specimen of Araucaria angustifolia from the south of Brazil was analyzed for ¹³C/¹²C variations in the cellulose of the tree rings. Those data, when compared with the growth pattern of the tree, showed a good correlation (r = ? 0.72) over a period of 200 years. A collection of six European trees was analyzed for the same effect and, although the expected inverse relation is evident from the graphical representation, the correlation coefficients are small. This is certainly due to the large scatter of δ¹³C data from those trees.     

The effect of floods on the transport of suspended sediments and contaminants: a case study from the estuary of the Dese River (Venice Lagoon, Italy)

A flood event was investigated in a measurement section of the estuary of the Dese River, the major tributary of the Venice Lagoon (mean annual discharge=7.5 m3/s), to observe the variations induced by the flow on the physico-chemistry of the water column and the transport of particles and pollutants. The flood was generated by a typical summer storm, which had a return period of 2 years. The study was based on the continuous recording of the discharge and the measurement of both current speed and physico-chemical variables along the vertical profile. Water samples were also collected for the analysis of total and dissolved heavy metals (As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Zn), and nutrients (TKN, N-NO3-, N-NO2-, N-NH3, total phosphorous, P-PO43-). The suspended particle matter (SPM) concentration increased in the water column during the flood, and the discharge versus SPM relationship showed a counterclockwise hysteresis. The occurrence of hysteresis was related to the delayed response of the load, deriving from the runoff on the basin soils with respect to materials mobilized from the streambed in the initial phases of the flood. The transport of most of the analysed heavy metals was driven by the SPM. The increase in concentration of this parameter significantly affected the amount of Fe, Cu, Pb, Cr, Ni, and partially Zn transported by the stream. Among nutrients, N-NO3- concentration also increased significantly during the flood, due to the runoff on agricultural surfaces. The study allowed describing the mechanisms of load generation with high flow magnitudes, highlighting the importance of floods in the transport of materials and pollutants from the drainage basin to the Venice Lagoon.     

Performance of a narrow buffer strip in abating agricultural pollutants in the shallow subsurface water flux

The performance of a narrow buffer strip in abating dissolved P, electrical conductivity and herbicides (terbuthylazine, alachlor, nicosulfuron, pendimethalin, linuron) in subsurface water coming from cropland was tested in an experiment carried out on the low plains of the Veneto Region (NE Italy). The experiment lasted from December 1997 to June 1999, monitoring subsurface water quality entering and exiting a buffer composed of a grass strip (5 m wide) and 1 m wide row of trees. Dissolved phosphorus concentrations were reduced by almost 100% passing through the buffer and in most cases exiting water satisfied the limit for avoiding eutrophication. A positive effect was also detected on ECW (reduced by 20%), while pH was not significantly altered. Herbicide concentration abatement varied between 60 and 90%, depending on the chemical and the time elapsed since application.     

Taxing overexploited open-access fisheries: the role of demand elasticity

The paper aims at identifying the effects exerted by a tax levy on an overexploited and previously unregulated fishery. The analysis is carried out by means of a dynamic model that includes fish stock and harvesting effort as state variables. Attention is focused on the role played by demand elasticity which is shown to affect both transients and equilibria.According to the analysis, a levy induces a contraction in effort, which is sharper in the short term. As a consequence, the fish population recovers and ultimately settles at a higher equilibrium level. Therefore, a larger amount of fish is caught in the long run and sold at a lower price than in the unregulated setting. The more inelastic the demand, the smaller both the equilibrium price for fish and the tax imposed.     

Lichen biomonitoring of trace metals in the Pistoia area (central northern Italy)

The epiphytic lichen Parmelia caperata (L.) Ach. was used as bioaccumulator of the heavy metals Cd, Cr, Cu, Hg, Ni, Pb and Zn in the environs of the town of Pistoia (central northern Italy). The concentrations of Cd, Cr, Ni, Hg and Pb were comparable with those found in areas not subject to atmospheric pollution. Copper and especially Zn were found in rather high concentrations. Fertilizers and pesticides were the main source of atmospheric contamination.     

Side biases in humans (Homo sapiens): three ecological studies on hemispheric asymmetries

Hemispheric asymmetries and side biases have been studied in humans mostly in laboratory settings, and evidence obtained in naturalistic settings is scarce. We here report the results of three studies on human ear preference observed during social interactions in noisy environments, i.e., discotheques. In the first study, a spontaneous right-ear preference was observed during linguistic exchange between interacting individuals. This lateral bias was confirmed in a quasi-experimental study in which a confederate experimenter evoked an ear-orienting response in bystanders, under the pretext of approaching them with a whispered request. In the last study, subjects showed a greater proneness to meet an experimenter’s request when it was directly addressed to the right rather than the left ear. Our findings are in agreement both with laboratory studies on hemispheric lateralization for language and approach/avoidance behavior in humans and with animal research. The present work is one of the few studies demonstrating the natural expression of hemispheric asymmetries, showing their effect in everyday human behavior.