GaN LNAs for Robust Receiving Systems in Radar and Space Applications

In this contribution a series of integrated circuits and methodologies, purposely developed for application in microwave receiving subsystems, will be presented. The integrated circuits, realized in GaN integrated technologies by different suppliers, find their applications in telecom systems as well as in RADAR ones, mainly for space-based apparatuses. The respective performance, as well as the key design methods will be presented in the contribution for bandwidths ranging from S-Band up to K-Band

A particle model of rolling grain ripples under waves

A simple model is presented for the formation of rolling grain ripples on a flat sand bed by the oscillatory flow generated by a surface wave. An equation of motion is derived for the individual ripples, seen as "particles", on the otherwise flat bed. The model account for the initial apperance of the ripples, the subsequent coarsening of the ripples and the final equilibrium state. The model is related to physical parameters of the problem, and an analytical approximation for the equilibrium spacing of the ripples is developed. It is found that the spacing between the ripples scale with the square-root of the non-dimensional shear stress (the Shields parameter) on a flat bed. The results of the model are compared with measurements, and reasonable agreement between the model and the measurements is demonstrated.Comment: 9 pages incl. figures. Revised versio

Seismically induced ground effects of the 1805, 1930 and 1980 earthquakes in the Southern Apennines (Italy

Seismically induced environmental effects (in particular, surfacefaults, ground cracks, slope failures, liquefaction, soil compaction, hydrological changes, tsunamis) are assumed to provide fundamentalinformation on the earthquake size and its intensity field, crucial for a more efficient seismic hazard assessment. Accordingly, this study is aimed at substantiating this assumption by showing that the knowledge about ground effects acquired in recent earthquakes, when combined with that illustrated in historical documents, allows to buildan improved picture of historic seismic events, with respect to that usually provided by the solely damage-based macroseismic scales. In this perspective, the environmental effects are analysed and cataloguedof three of the most ruinous earthquakes in Southern Italy of the last two centuries: the July 26,1805, Molise event (XI MCS, M 6.8), the July 23, 1930, Irpinia event (X MCS, M 6.7), and the November 23, 1980 Campania-Basilicata event (X MSK, Ms 6.9). The distribution of the earthquake environmental effects, in particular their distance from the known or supposed causative fault, has been investigated to obtain a more detailed and comprehensive picture of the macroseismic field, a key parameter in seismic hazard assessment and seismic zonation. KEY WORDS: historical seismicity, intensity, ground effects, earthquak

Fatigue life under non-Gaussian random loading from various models

Fatigue test results on the 10HNAP steel under constant amplitude and random loading with non-Gaussian probability distribution function, zero mean value and wide-band frequency spectrum have been used to compare the life time estimation of the models proposed by Bannantine, Fatemi–Socie, Socie, Wang–Brown, Morel and Łagoda–Macha. Except the Morel proposal which accumulates damage step by step with a proper ethodology, all the other models use a cycle counting method. The rainflow algorithm is used to extract cycles from random histories of damage parameters in time domain. In the last model, where a strain energy density parameter is employed, additionally spectral method is evaluated for fatigue life calculation in the frequency domain. The best and very similar results of fatigue life assessment have been obtained using the models proposed by Socie and by Łagoda–Macha, both in time and frequency domains for the last one.With the support of the Commission of the European Communities under the FP5, GROWTH Programme, contract No. G1MA-CT-2002-04058 (CESTI)

Whole-Transcriptome Analysis Unveils the Synchronized Activities of Genes for Fructans in Developing Tubers of the Jerusalem Artichoke

Helianthus tuberosus L., known as the Jerusalem artichoke, is a hexaploid plant species, adapted to low-nutrient soils, that accumulates high levels of inulin in its tubers. Inulin is a fructose-based polysaccharide used either as dietary fiber or for the production of bioethanol. Key enzymes involved in inulin biosynthesis are well known. However, the gene networks underpinning tuber development and inulin accumulation in H. tuberous remain elusive. To fill this gap, we selected 6,365 expressed sequence tags (ESTs) from an H. tuberosus library to set up a microarray platform and record their expression across three tuber developmental stages, when rhizomes start enlarging (T-0), at maximum tuber elongation rate (T-3), and at tuber physiological maturity (T-m), in "VR" and "K8-HS142"clones. The former was selected as an early tuberizing and the latter as a late-tuberizing clone. We quantified inulin and starch levels, and qRT-PCR confirmed the expression of critical genes accounting for inulin biosynthesis. The microarray analysis revealed that the differences in morphological and physiological traits between tubers of the two clones are genetically determined since T-0 and that is relatively low the number of differentially expressed ESTs across the stages shared between the clones (93). The expression of ESTs for sucrose:sucrose 1-fructosyltransferase (1-SST) and fructan:fructan 1-fructosyltransferase (1-FFT), the two critical genes for fructans polymerization, resulted to be temporarily synchronized and mirror the progress of inulin accumulation and stretching. The expression of ESTs for starch biosynthesis was insignificant throughout the developmental stages of the clones in line with the negligible level of starch into their mature tubers, where inulin was the dominant polysaccharide. Overall, our study disclosed candidate genes underpinning the development and storage of carbohydrates in the tubers of two H. tuberosus clones. A model according to which the steady-state levels of 1-SST and 1-FFT transcripts are developmentally controlled and might represent a limiting factor for inulin accumulation has been provided. Our finding may have significant repercussions for breeding clones with improved levels of inulin for food and chemical industry

A natural saline soil as a model for understanding to what extent the concentration of salt affects the distribution of microorganisms

Soils preserve and sustain life. Their health and functioning are crucial for crop production and for the maintenance of major ecosystem services. Human induced salinity is one of the main soil threats that reduces soil fertility and affect crop yields. In recent times, great attention has been paid to the general shortage of arable land and to the increasing demand for ecological restoration of areas affected by salinization processes. Despite the diffuse interest on the effects of salinization on plants\u2019 growth, and all the derived socioeconomic issues, very few studies analyzed the ecology of the microbial species in naturally saline soils and the resilience of biological fertility in these extreme habitats. Microorganisms inhabiting such environments may share a strategy, may have developed multiple adaptations for maintaining their populations, and cope eventually to extreme conditions by altruistic or cooperative behaviors for maintaining their metabolism active. The understanding and the knowledge of the composition and distribution of microbial communities in natural hypersaline soils can be interesting for ecological reasons but also to develop new restoration strategy where soil fertility was compromised by natural accidents or human mismanagement. The aim of this research was to provide specific information on saline soils in Italy, stressing mainly their distribution, the socioeconomic issues and the understanding of the characterizing ecological processes. Moreover, natural saline soils were used as a model for understanding to what extent the concentration of salt can affect some basic microbial processes. In the present study, physical, chemical and microbiological soil properties were investigated in the shallower horizons of natural salt affected soils in Sicily (Italy), where some ecological contrasting variables acted as strong drivers in fungal and bacterial spatial distribution. Furthermore, the interface between biological and geochemical components in the surface of that peculiar habitat was investigated to evaluate the organization and diversity of the phototrophic and heterotrophic microorganisms. Sixteen soil samples from A horizons were collected according to a random sampling scheme. Bacterial and archaeal communities were characterized by their 16S rDNA genes with T-RFLP method. A total of 92 genera were identified from the 16S pyrosequencing analysis suggesting that cyanobacteria and communities of sulfur bacteria might directly or indirectly promote the formation of protective envelope. Some bacterial phyla appeared spread in the whole area, whatever the salinity gradient, while other groups showed a distribution linked to very compartmentalised soil properties, such as the presence of saline crusts in the soil surface. Results show that saline soils couldn\u2019t contain just one single microbial community selected to withstand extreme osmotic phenomena, but many communities that can be variously correlated to one or more environmental parameters having great importance for the maintenance of the overall homeostasis

Slip distributions on active normal faults measured from LiDAR and field mapping of geomorphic offsets: an example from L\u2019Aquila, Italy, and implications for modelling seismic moment release

Surface slip distributions for an active normal fault in central Italy have been measured using terrestrial laser scanning (TLS), in order to assess the impact of changes in fault orientation and kinematics when modelling subsurface slip distributions that control seismic moment release. The southeastern segment of the surface trace of the Campo Felice active normal fault near the city of L\u2019Aquila was mapped and surveyed using techniques from structural geology and using TLS to define the vertical and horizontal offsets of geomorphic slopes since the last glacial maximum (15 \ub13 ka). The fault geometry and kinematics measured from 43 sites and throw/heave measurements from geomorphic offsets seen on 250 scarp profiles were analysed using a modification of the Kostrov equations to calculate the magnitudes and directions of horizontal principal strain-rates. The map trace of the studied fault is linear, except where a prominent bend has formed to link across a former left-stepping relay-zone. The dip of the fault and slip direction is constant across the bend. Throw-rates since 15 \ub13 ka decrease linearly from the fault centre to the tip, except in the location of the prominent bend where higher throw rates are recorded. Vertical coseismic offsets for two palaeoearthquake ruptures seen as fresh strips of rock at the base of the bedrock scarp also increase within the prominent bend. The principal strain-rate, calculated by combining strike, dip, slip-direction and post 15 \ub13 ka throw, decreases linearly from the fault centre towards the tip; the strain-rate does not increase across the prominent fault bend. The above shows that changes in fault strike, whilst having no effect on the principal horizontal strain-rate, can produce local maxima in throw-rates during single earthquakes that persist over the timescale of multiple earthquakes (15 \ub13 ka). Detailed geomorphological and structural investigation of active faults is therefore a critical input in order to properly define fault activity for the purpose of accurate seismic hazard assessment. We discuss the implications of modelling subsurface slip distributions for earthquake ruptures through inversion of GPS, InSAR and strong motion data using planar fault approximations, referring to recent examples on the nearby Paganica fault that ruptured in the Mw 6.3 2009 L\u2019Aquila Earthquak

The behavior of rare soil gases in a seismically active area: the Fucino basin (central Italy)

Soil-gas (He, Rn) concentrations were performed to test their sensitivity for locating fault or fracture systems also when masked by non-cohesive lithologies, and to investigate about the gas-bearing properties of seismogenic faults. The Fucino basin (central Italy) was chosen as test site because it displays a network of surface and shallow-buried active faults within the valley floor that were partially reactivated during the 1915 Avezzano earthquake (Ms47.0). The highest radon values were found aligned along the most important faults bordering the eastern and the north-western sides of the plain. Moderately anomalous values of radon activity occur along the faults located in the depression of the historical lake. Highest helium values prevail in the western part of the plain, in correspondence of a horst structure inferred to be as the prolongation of the Vallelonga-Trasacco ridge. The study provides constraints on the spatial influence of tectonics and geology on deep-seated gas migration toward the surface