Environmental NMR: Fast-field-cycling Relaxometry

Fast-field-cycling (FFC) NMR relaxometry deals with the variation of the spin–lattice relaxation times (T1) in a complex system, as the strength of the applied magnetic field is changed. Information about molecular dynamics can be achieved. Until now, only model theories for FFC NMR relaxometry have been developed for polymer and material sciences. Just a few applications have been performed in the environmental sciences. These mainly deal with soil porosity, rock permeability, biomass transformations, and natural organic matter dynamics. Further, FFC NMR relaxometry can also be applied to monitor the environmental fate of contaminants, to understand the dynamics of nutrients at the soil–plant interface, and to evaluate reaction mechanisms in heterogeneous catalysis for the development of green reactions. This article summarizes the advances of the technique in environmental investigations and describes the tools used to monitor dynamics of organic and inorganic molecules in environmental compartments

Effects of human disturbance on reproductive success and population viability of<i>Serapias cordigera</i>(Orchidaceae)

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Global Social Science: Dislocation of the Abyssal Line and Post-Abyssal Epistemologies and Practices

The essay deals with the hypothesis of a global process of dislocation of the “abyssal line”, adopting the concept of “abyssal exclusions” by Boaventura de Sousa Santos. The Portuguese sociologist, inspired in particular by the postcolonial and the decolonial debate, defines abyssal exclusion as a specific type of socio-political “absence” linked to “colonial sociability”, the “invisibilization” of those excluded through a specific process that places subaltern social groups outside the social contract. This perspective proves useful today to frame the development of new forms of social exclusion that reproduce the South within the North. This exploitation is still legitimated by specific forms of “cultural violence”: inferiorization of the alterities and the disavowal of non-western declinations of social order or social justice. This refers in particular to some social experiences that we will analyze including forms of sociability emerging across Europe between those denied asylum, and situations where forms of exploitation due to the colonial sociability live side by side with forms of labor exploitation due to the weakening of social protection in European welfare. systems. But the essay explores how these abyssal absences could also be analyzed as “social emergences”: strategies of existence that manipulate the radical exclusion. Starting from the hypothesis that a dislocation of the abyssal line is underway, the essay proposes a type of research aimed at shedding light on these social experiences through “post-abyssal” epistemologies and research practices

Molecular identification of mycorrhizal fungi in Dactylorhiza sambucina (Orchidaceae)

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Numerical Methods for the Nonlocal Wave Equation of the Peridynamics

In this paper we will consider the peridynamic equation of motion which is described by a second order in time partial integro-differential equation. This equation has recently received great attention in several fields of Engineering because seems to provide an effective approach to modeling mechanical systems avoiding spatial discontinuous derivatives and body singularities. In particular, we will consider the linear model of peridynamics in a one-dimensional spatial domain. Here we will review some numerical techniques to solve this equation and propose some new computational methods of higher order in space; moreover we will see how to apply the methods studied for the linear model to the nonlinear one. Also a spectral method for the spatial discretization of the linear problem will be discussed. Several numerical tests will be given in order to validate our results

Sorption Thermodynamics of CO2, H2O, and CH3OH in a Glassy Polyetherimide: A Molecular Perspective

In this paper, the sorption thermodynamics of low-molecular-weight penetrants in a glassy polyetherimide, endowed with specific interactions, is addressed by combining an experimental approach based on vibrational spectroscopy with thermodynamics modeling. This modeling approach is based on the extension of equilibrium theories to the out-of-equilibrium glassy state. Specific interactions are accounted for in the framework of a compressible lattice fluid theory. In particular, the sorption of carbon dioxide, water, and methanol is illustrated, exploiting the wealth of information gathered at a molecular level from Fourier-transform infrared (FTIR) spectroscopy to tailor thermodynamics modeling. The investigated penetrants display a different interacting characteristic with respect to the polymer substrate, which reflects itself in the sorption thermodynamics. For the specific case of water, the outcomes from molecular dynamics simulations are compared with the results of the present analysis

Drilling down hotspots of infraspecific diversity to bring them into on-ground conservation of threatened species

Unprecedented rates of biodiversity loss raise the urgency for preserving species ability to cope with ongoing global changes. An approach in this direction is to target intra-specific hotspots of genetic diversity as conservation priorities. However, these hotspots are often identified by sampling at a spatial resolution too coarse to be useful in practical management of threatened species, hindering the long-appealed dialog between conservation stakeholders and conservation genetic researchers. Here, we investigated the spatial and temporal variation in species presence, genetic diversity, as well as potential risk factors, within a previously identified hotspot of genetic diversity for the endangered Apennine yellow-bellied toad Bombina pachypus. Our results show that this hotspot is neither a geographically homogeneous nor a temporally stable unit. Over a time-window spanning 10–40 years since previous assessments, B. pachypus populations declined in large portions of their hotspot, and their genetic diversity levels decreased. Considering the demographic trend, genetic and epidemiological data, and models of current and future climatic suitability, populations at the extreme south of the hotspot area still qualify for urgent in-situ conservation actions, whereas northern populations would be better managed through a mix of in-situ and ex-situ actions. Our results emphasize that identifying hotspots of genetic diversity, albeit an essential step, does not suffice to warrant on-ground conservation of threatened species. Hotspots should be analyzed at finer geographic and temporal scales, to provide conservation stakeholders with key knowledge to best define conservation priorities, and to optimize resource allocation to alternative management practices

Second spectrum of charge carrier density fluctuations in graphene due to trapping/detrapping processes

We investigate the second spectrum of charge carrier density fluctuations in graphene within the McWorther model, where noise is induced by electron traps in the substrate. Within this simple picture, we obtain a closed-form expression including both Gaussian and non-Gaussian fluctuations. We show that a very extended distribution of switching rates of the electron traps in the substrate leads to a carrier density power spectrum with a non-trivial structure on the scale of the measurement bandwidth. This explains the appearance of a $1/f$ component in the Gaussian part of the second spectrum, which adds up to the expected frequency-independent term. Finally, we find that the non-Gaussian part of the second spectrum can become quantitatively relevant by approaching extremely low temperatures.Comment: 10 pages, 2 figure