The fate of amino acids adsorbed on mineral matter

We present here selected results recently obtained on the molecular characterization of amino acids adsorption on oxide minerals and their further polymerization by thermal activation, in the general frame of assessing Bernal's hypothesis on the origin of biopolymers on mineral surfaces. Adsorption mechanisms may be identified by a combination of vibrational spectroscopy, ¹³C solid-state NMR, and molecular modeling. Depending on a particular amino acid, the oxide surface investigated, and the water activity during adsorption (i.e., whether it is carried out from the gas phase or from an aqueous solution), contributions from electrostatic adsorption, outer-sphere and inner-sphere (coordination) complexes may be observed. These mechanisms result in significant adsorption selectivities from equimolar mixtures of different amino acids. Upon thermal activation at moderate temperatures (150-160 °C), clean polymerization events occur and can easily be observed by thermogravimetric analysis. There are some hints of selectivity in this step too. The water activity during thermal treatment plays an important role for the thermodynamics of polymerization.     

Cooperative evolutionary algorithm for space trajectory optimization

A hybrid evolutionary algorithm which synergistically exploits differential evolution, genetic algorithms and particle swarm optimization, has been developed and applied to spacecraft trajectory optimization. The cooperative procedure runs the three basic algorithms in parallel, while letting the best individuals migrate to the other populations at prescribed intervals. Rendezvous problems and round-trip Earth–Mars missions have been considered. The results show that the hybrid algorithm has better performance compared to the basic algorithms that are employed. In particular, for the rendezvous problem, a 100% efficiency can be obtained both by differential evolution and the genetic algorithm only when particular strategies and parameter settings are adopted. On the other hand, the hybrid algorithm always attains the global optimum, even though nonoptimal strategies and parameter settings are adopted. Also the number of function evaluations, which must be performed to attain the optimum, is reduced when the hybrid algorithm is used. In the case of Earth–Mars missions, the hybrid algorithm is successfully employed to determine mission opportunities in a large search space.     

Resonant Fly-by Missions to Near Earth Asteroids

The authors here propose a mission scenario, aimed at close exploration of a Near-Earth Asteroid, exploiting low-V resonant trajectories. These trajectories allow repeated fly-bys of a chosen target. A selection procedure, which has been used to find some interesting mission opportunities in the 2005-2015 time frame, is described and the corresponding detailed mission profiles are derived, using an indirect optimization method.     

High-frequency loading effects by the Ligurian Sea — a statistical investigation

In the present work we analyzed the high-frequency band of crustal tilts at Genoa in order to investigate indirect loading effects by the quarter-diurnal oceanic tides, as well as by an observed oceanic oscillation of 3.66 h which was previously ascribed to the proper oscillation of the Ligurian Sea. With this aim two hourly series of tidal observation recorded by an horizontal pendulum along a NS direction have been submitted to spectral analyses (1 May 1965-28 February 1966; 1 June 1966-31 December 1966).Power spectra revealed two peaks near the periods of 6.15 and 3.66 h and highly resolved Fourier spectra allowed us to detect the loading effects by the oceanic tides M₄, MS₄ and MK₄. As regards to the oscillation of 3.66 h we have found a spreading of spectral lines and non-significant values for the phases. This result provides a decisive verification of the existence of a proper oscillation of the Ligurian Sea regarded as a wide oscillating system with an open boundary from Nice (Côte d'Azur) to Calvi (Corsica).Finally, a spectral analysis performed on sea-level observations at Genoa revealed a complete correspondence between ocean and earth oscillations in the quarter-diurnal band and at the frequency of the longitudinal free oscillation of the Ligurian basin, with a mean amplitude ratio of about 1 mseca/mm.     

Stratospheric ozone depletion: a key driver of recent precipitation trends in South Eastern South America

On a hemispheric scale, it is now well established that stratospheric ozone depletion has been the principal driver of externally forced atmospheric circulation changes south of the Equator in the last decades of the 20th Century. The impact of ozone depletion has been felt over the entire hemisphere, as reflected in the poleward drift of the midlatitude jet, the southward expansion of the summertime Hadley cell and accompanying precipitation trends deep into the subtropics. On a regional scale, however, surface impacts directly attributable to ozone depletion have yet to be identified. In this paper we focus on South Eastern South America (SESA), a region that has exhibited one of the largest wetting trends during the 20th Century. We study the impact of ozone depletion on SESA precipitation using output from 6 different climate models, spanning a wide range of complexity. In all cases we contrast pairs of model integrations with and without ozone depletion, but with all other forcings identically specified. This allows for unambiguous attribution of the computed precipitation trends. All 6 climate models consistently reveal that stratospheric ozone depletion results in a significant wetting of SESA over the period 1960–1999. Taken as a whole, these model results strongly suggest that the impact of ozone depletion on SESA precipitation has been as large as, and quite possibly larger than, the one caused by increasing greenhouse gases over the same period.     

Capacity and economic efficiency in small-scale fisheries: Evidence from the Mediterranean Sea

To design an effective capacity management plan for small-scale fisheries one must understand what one is measuring and define its capacity. As recognized by some authors, overcapacity is a problem that generally affects small-scale fisheries just as much as it does other types of fishing. This study aims to estimate fishing capacity, technical efficiency, scale efficiency and capacity utilization in a particular small-scale fishery in the Mediterranean, i.e., the Northwest Sardinian fleet in Italy. A non-parametric approach using a data envelopment analysis (DEA) model was applied to a sample of trawls in order to estimate their economic capacity, and related measurements were taken. The capacity and efficiency with reference to two different alternative scenarios were also calculated.     

X‐ray luminosity functions of different morphological and X‐ray type AGN populations

Luminosity functions are one of the most important observational clues when studying galaxy evolution over cosmic time. In this paper we present the X‐ray luminosity functions for X‐ray detected AGN in the SXDS and GWS fields. The limiting fluxes of our samples are 9.0 ×10^–15 and 4.8 ×10^–16 erg cm^–2 s^–1 in the 0.5–7.0 keV band in the two fields, respectively. We carried out analysis in three X‐ray bands and in two redshift intervals up to z ≤ 1.4. Moreover, we derive the luminosity functions for different optical morphologies and X‐ray types. We confirm strong luminosity evolution in all three bands, finding the most luminous objects at higher redshift. However, no signs of density evolution are found in any tested X‐ray band. We obtain similar results for compact and early‐type objects. Finally, we observe the “Steffen effect”, where X‐ray type‐1 sources are more numerous at higher luminosities in comparison with type‐2 sources. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Unidata’s Common Data Model mapping to the ISO 19123 Data Model

Access to real-time distributed Earth and Space Science (ESS) information is essential for enabling critical Decision Support Systems (DSS). Thus, data model interoperability between the ESS and DSS communities is a decisive achievement for enabling cyber-infrastructure which aims to serve important societal benefit areas. The ESS community is characterized by a certain heterogeneity, as far as data models are concerned. Recent spatial data infrastructures implement international standards for the data model in order to achieve interoperability and extensibility. This paper presents well-accepted ESS data models, introducing a unified data model called the Common Data Model (CDM). CDM mapping into the corresponding elements of the international standard coverage data model of ISO 19123 is presented and discussed at the abstract level. The mapping of CDM scientific data types to the ISO coverage model is a first step toward interoperability of data systems. This mapping will provide the abstract framework that can be used to unify subsequent efforts to define appropriate conventions along with explicit agreed-upon encoding forms for each data type. As a valuable case in point, the content mapping rules for CDM grid data are discussed addressing a significant example.