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We report an excellent realization of the highly non-classical incommensurate spin-density wave (SDW) state in the quantum frustrated antiferromagnetic insulator Cs$_2$CoBr$_4$. In contrast to the well-known Ising spin chain case, here the SDW is stabilized by virtue of competing planar in-chain anisotropies and frustrated interchain exchange. Adjacent to the SDW phase is a broad $m = 1/3$ magnetization plateau that can be seen as a commensurate locking of the SDW state into the up-up-down (UUD) spin structure. This represents the first example of long-sought SDW-UUD transition in triangular-type quantum magnets., Comment: 13 pages, 13 figures

Inelastic neutron scattering is used to investigate the temperature dependence of spin correlations in the 3-dimensional XY antiferromagnet $\mathrm{Ni}{({\mathrm{Cl}}_{1\ensuremath{-}x}{\mathrm{Br}}_{x})}_{2}\ifmmode\cdot\else\textperiodcentered\fi{}4\mathrm{SC}{({\mathrm{NH}}_{2})}_{2}, x=0.14(1)$, tuned close to the chemical-composition-induced soft-mode transition. The local dynamic structure factor shows $\ensuremath{\hbar}\ensuremath{\omega}/T$ scaling behavior characteristic of a quantum-critical point. The deviation of the measured critical exponent from spin wave theoretical expectations is attributed to disorder. Another effect of disorder is local excitations above the magnon band. Their energy, structure factor, and temperature dependence are well explained by simple strong-bond dimers associated with Br-impurity sites.

We have found an unusual competition of two frustration mechanisms in the 2D quantum antiferromagnet Cs2CoBr4. The key actors are the alternation of single-ion planar anisotropy direction of the individual magnetic Co2+ ions, and their arrangement in a distorted triangular lattice structure. In particular, the uniquely oriented Ising-type anisotropy emerges from the competition of easy-plane ones, and for a magnetic field applied along this axis one finds a cascade of five ordered phases at low temperatures. Two of these phases feature magnetization plateaux. The low-field one is supposed to be a consequence of a collinear ground state stabilized by the anisotropy, while the other plateau bears characteristics of an "up-up-down" state exclusive for lattices with triangular exchange patterns. Such coexistence of the magnetization plateaux is a fingerprint of competition between the anisotropy and the geometric frustration in Cs2CoBr4., Physical Review Research, 2 (4), ISSN:2643-1564

A Faraday force magnetometer is presented for measurements of magnetization at temperatures down to 100~mK and in magnetic fields up to 14~T. The specimen is mounted on a flexible cantilever forming a force-sensing capacitor in combination with a fixed back plate. Two different cantilever designs are presented. A torsion resistant cantilever allows to measure magnetization of highly anisotropic single crystal samples. Measurements of the metal organic quantum magnets (C$_5$H$_{12}$N)$_2$CuBr$_4$ (BPCB) and NiCl$_2$$\cdot$4 SC(NH$_2$)$_2$ (DTN) demonstrate the device's capabilities. Routinely, a specimen's magnetic moment is measured with a resolution better than $10^{-7}$ A$\,$m$^2$ ($10^{-4}$ emu). The device in miniaturized to fit is almost any cryostat.

A critical problem in atmospheric remote sensing is to perform systematic water vapor (WV) measurements in the lowest part of the troposphere (~5-6 km) on a global scale, which helps to improve both climate modeling and numerical weather prediction capabilities at short time scale. An innovative approach (the Normalized Differential Spectral Attenuation-NDSA) has been proposed capable to estimate the integrated water vapour (IWV) along microwave links crossing the troposphere based on attenuation measurements made in the Ku/K bands. Two ESA studies provided an exhaustive insight into all theoretical aspects of the NDSA technique applied to the case of two counter-rotating LEO satellites. The 2-years long SWAMM project, started in 2016 and funded by Tuscany Region, aims at implementing an instrument able to perform NDSA measurements at 19 GHz between a transmitter at ground and a receiver onboard a stratospheric platform. The features of the NDSA instrumentation (low cost, small weight and size) and the advantages brought by NDSA measurements in the configuration illustrated below make this approach particularly attractive for being exploited in Earth-HAPS links.

Measuring water vapor (WV) in the lowest troposphere (below 10 km) from space with sufficient accuracy is a still critical issue. However, it is well recognized WV measurements would help improving both climate modeling and numerical weather prediction capabilities at short time scale. To solve this problem, a novel approach (Normalized Differential Spectral Attenuation-NDSA) has been proposed, based on attenuation measurements made at Ku/K bands and capable to estimate the integrated water vapour (IWV) along microwave links crossing the troposphere. NDSA is based on the estimate of a parameter (called spectral sensitivity, S) related to the differential attenuation undergone by a pair of tone signals separated by a fractional band of less than 2%. It was demonstrated that S can be directly converted into IWV through linear relationships. Research studies, funded by ESA, provided an exhaustive insight into all theoretical aspects of the NDSA technique from space, but it still needs to be demonstrated with real measurements before moving toward space applications. The main goal of a recent project (SWAMM-Sounding Water Vapour by Attenuation Microwave Measurements), funded by Regione Toscana - Italy is to develop a low-cost radio link to perform the first NDSA measurements. Within the project the instrument is designed and built and preliminary tests based on a ground-to-ground link have been recently conducted to validate the concept. In this tests the transmitter was places on a mountain (around 200 m a.s.l.) and the receiver at about sea level for a link of around 80 Km. Project results, first measurements, retrieval tests and perspectives for moving toward a space configuration will be presented at the conference.

Data collected by weather radars, typically at S, C and X-band frequencies, and in particular those with dual-polarization capabilities are frequently used to investigate observations of precipitation events collected by satellite borne instruments, such as real or synthetic aperture radars operating at different frequencies. Satellite borne SAR aims at providing surface characteristics for different applications in "all weather" conditions. However, precipitation affects SAR images depending on the employed wavelength, and results in attenuation of surface backscattering, additional backscattering from sampled precipitation, geometric and radiometric distortion. At the 9.6 GHz frequency (X band) of the Italian Space Agency Cosmo Sky Med (CSK®) constellation (and by other SARs currently in orbit), attenuation induced by intense precipitation can be significant, masking features of the observed surface. Over land, attenuation prevails over increased backscattering due to precipitation sampled by radar beam, often negligible with respect to terrain backscattering, also influenced by the terrain wetting. Coincident dual polarization radar measurements allow to estimate X band specific attenuations at the frequency and incidence angle of SAR [1][2]. A classification of hydrometeors obtained from weather radar polarimetric signature of precipitation can be used to select the proper algorithms for specific attenuation [3]. Over the sea precipitation induces also changes in the sea NRCS that can be treated by resorting to rainfall fields retrieved by weater radar and a proper modelling [4][5]. Precipitation cases collected in 2 years by the CSK satellites over terrain and sea are analyzed through a model applied to simultaneous observations collected by C-band

By monitoring dopamine metabolism in rat pheochromocytoma derived PC12 cell cultures during extended treatment with manganese chloride, we assessed the functional changes occurring in a dopaminergic system during the development of manganese-induced damage. Besides eliciting a specific toxic effect on PC12 cells, manganese induced the complete disappearance of extracellular (free) but not intracellular (vesicle stored) dopamine and its metabolite 3,4-dihydroxyphenylacetic acid. This effect was observed also using low manganese concentrations (1 μM) and mainly occurred by non-enzymatic catechol oxidation since it was still evident in a cell free medium and it was fully prevented by ascorbic acid but not by reduced glutathione. The possibility of a mere “non-biological” action was ruled out by the observation of an irreversible effect of manganese as manifested by the cells' apparent inability to release dopamine or 3,4-dihydroxyphenylacetic acid into the culture medium even after complete manganese removal (post-manganese incubation). That a free radical mechanism was not involved in the genesis of this irreversible effect was shown by the fact that neither ascorbic acid, catalase, superoxide dismutase nor glutathione-peroxidas were able to prevent the decrease in catecholamine levels in the “post-manganese” incubation medium when added at the same time as the manganese. The results establish this PC12 cell system as an in vitro model for studying interactions between manganese and catechols and provide a detailed description of the nature of the neurochemical alterations that this heavy metal can induce in a dopaminergic system.

By testing the effect of spermine on N-methyl-D-aspartate (NMDA)-evoked [3H]noradrenaline release in rat hippocampal slices, we revealed a presynaptic spermine-sensitive NMDA receptor most probably localized on noradrenergic terminals. Spermine (1 mM), per se totally inactive, was able to reverse the tetrodotoxin-induced blockade of the NMDA effect, restoring tritium efflux to approximately 50% of the NMDA-evoked release measured in the absence of tetrodotoxin. This effect was partially antagonized by D(-)-2-amino-7-phosphonoheptanoic acid. Our results may help to elucidate the role that spermine exerts on excitatory amino acids receptors.