Experimental determination of the quasi-projectile mass with measured neutrons

The investigation of the isospin dependence of multifragmentation reactions relies on precise reconstruction of the fragmenting source. The criteria used to assign free emitted neutrons, detected with the TAMU Neutron Ball, to the quasi-projectile source are investigated in the framework of two different simulation codes. Overall and source-specific detection efficiencies for multifragmentation events are found to be model independent. The equivalence of the two different methods used to assign experimentally detected charged particles and neutrons to the emitting source is shown. The method used experimentally to determine quasi-projectile emitted free neutron multiplicity is found to be reasonably accurate and sufficiently precise as to allow for the study of well-defined quasi-projectile sources.Comment: 10 pages, 8 figures. To be submitted to Nucl. Instr. and Meth.

Asymmetry Dependence of the Nuclear Caloric Curve

A basic feature of the nuclear equation of state is not yet understood: the dependence of the nuclear caloric curve on the neutron-proton asymmetry. Predictions of theoretical models differ on the magnitude and even the sign of this dependence. In this work, the nuclear caloric curve is examined for fully reconstructed quasi-projectiles around mass A=50. The caloric curve extracted with the momentum quadrupole fluctuation thermometer shows that the temperature varies linearly with quasi-projectile asymmetry (N-Z)/A. An increase in asymmetry of 0.15 units corresponds to a decrease in temperature on the order of 1 MeV. These results also highlight the importance of a full quasi-projectile reconstruction in the study of thermodynamic properties of hot nuclei

Physical, Biochemical and Biological Characterization of Two Opposite Areas in the Southern Adriatic Sea (Mediterranean Sea)

The Drini and Manfredonia Gulfs were investigated in May 2008 and April 2009, respectively. The gulfs are located in the South Eastern (Gulf of Drini) and South Western (Gulf of Manfredonia) Adriatic Sea. The areas are partially influ- enced by two main Adriatic surface currents: the Eastern Adriatic Current-EAC that flows north-westward along the eastern side, and the Western Adriatic Current-WAC that flows south-eastward along the western side of the basin. The spatial variations of temperature, salinity, fluorescence, dissolved oxygen concentration, Coloured Dissolved Or- ganic Matter-CDOM, nutrients, chlorophyll a and phytoplankton composition parameters in the two areas were ob- served and compared. CDOM regulates the penetration of UV light into the sea and plays an important role in many hydrological and biogeochemical processes on the sea surface layer including primary productivity. The phytoplankton specific diversity of the Gulf of Manfredonia showed a spring community with dinoflagellates (21 taxa) as the main important fraction, coccolithophorales (6 taxa) and diatoms with 10 identified taxa. The phytoplankton distribution along the eastern coast showed a different biodiversity: a prevalence of dinoflagellates (58 taxa) included harmful mi- croalgae such as Alexandrium, Dinophysis and Lingulodinium genus. Diatoms were less abundant, among them Pseudo-nitzschia was also reported which could include some potentially toxic species. Nanoplankton are ever abun- dant in offshore waters and an exceptional bloom of cyanobacteria was registered in Buna-Boyana estuary due to strong industrial impact. The gulfs showed similar physical and biochemical characteristics despite the WAC carried out along the western Adriatic Sea the water rich in nutrients from the major northern Italian rivers. No correlations were found between CDOM and chlorophyll a in the two areas and this implied that, probably, the primary source of CDOM might come from terrestrial input rather than the biological production from phytoplankton. The Gulf of Drini is impacted by the runoff of the Buna-Bojana River that makes this gulf an eutrophic area despite the mostly eastern side of the Adri- atic being an oligotrophic basin

Is the southeastern Adriatic Sea coastal strip 1 an eutrophic area?

The aim of the present study is to understand and assess the eutrophic state of the Buna-Bojana river delta coastal strip, in the southeastern Adriatic Sea, and contrast it with the northern Po river dominated shelf area. We present and compare observations of chemical and physical state variables from the two areas of the Adriatic Sea and we also use a numerical model output to depict the circulation structures of the two areas. The area affected by the Po River discharge extends at least one hundred kilometres southward of the delta and approximately twenty kilometres offshore. Maximum chlorophyll concentrations follow closely the river waters. Similarly to the northern Adriatic Sea, the Buna/Bojana river discharge extends northward along the coasts for one hundred kilometres and shows large maxima in chlorophyll. The two coastal areas have opposite dominant dynamical processes: while the Po river affected area is a downwelling region, the Buna/Bojana is characterized by upwelling favourable winds. However, during the period of study, upwelling is not a dominant feature of the circulation and both the shelf slope current and the along shore currents in the southeastern Adriatic Sea are northward, the along shore current probably dominated by the river runoff. Under these conditions, primary productivity is high in both areas which allows us to conclude that river plume dynamics with the associated nutrient inputs control the eutrophication state of the coastal strip, regardless of the general hydrodynamics regime of the southeastern Adriatic Sea are

Crop rotations sustain cereal yields under a changing climate

Agriculture is facing the complex challenge of satisfying increasing food demands, despite the current and projected negative impacts of climate change on yields. Increasing crop diversity at a national scale has been suggested as an adaptive measure to better cope with negative climate impacts such as increasing temperatures and drought, but there is little evidence to support this hypothesis at the field scale. Using seven long-term experiments across a wide latitudinal gradient in Europe, we showed that growing multiple crop species in a rotation always provided higher yields for both winter and spring cereals (average +860 and +390 kg ha−1 per year, respectively) compared with a continuous monoculture. In particular, yield gains in diverse rotations were higher in years with high temperatures and scant precipitations, i.e. conditions expected to become more frequent in the future, rendering up to c. 1000 kg ha−1 per year compared to monocultures. Winter cereals yielded more in diverse rotations immediately after initiation of the experiment and kept this advantage constant over time. For spring cereals, the yield gain increased over time since diversification adoption, arriving to a yearly surplus of c. 500 kg ha−1 after 50-60 years with still no sign of plateauing. Diversified rotations emerge as a promising way to adapt temperate cropping systems and contribute to food security under a changing climate. However, novel policies need to be implemented and investments made to give means and opportunities for farmers to adopt diversified crop rotations

Phase-separation of binary fluids in shear flow: a numerical study

The phase-separation kinetics of binary fluids in shear flow is studied numerically in the framework of the continuum convection-diffusion equation based on a Ginzburg-Landau free energy. Simulations are carried out for different temperatures both in d=2 and in d=3. Our results confirm the qualitative picture put forward by the large-N limit equations studied in \cite{noi}. In particular, the structure factor is characterized by the presence of four peaks whose relative oscillations give rise to a periodic modulation of the behavior of the rheological indicators and of the average domains sizes. This peculiar pattern of the structure factor corresponds to the presence of domains with two characteristic thicknesses whose relative abundance changes with time.Comment: 6 pages, 11 figures in .gif forma

Exciton-plasmon states in nanoscale materials: breakdown of the Tamm-Dancoff approximation

Within the Tamm-Dancoff approximation ab initio approaches describe excitons as packets of electron-hole pairs propagating only forward in time. However, we show that in nanoscale materials excitons and plasmons hybridize, creating exciton--plasmon states where the electron-hole pairs oscillate back and forth in time. Then, as exemplified by the trans-azobenzene molecule and carbon nanotubes, the Tamm-Dancoff approximation yields errors as large as the accuracy claimed in ab initio calculations. Instead, we propose a general and efficient approach that avoids the Tamm--Dancoff approximation, and correctly describes excitons, plasmons and exciton-plasmon states

A comprehensive overview on Kratom

Kratom (Mitragyna speciosa Korth) is a tropical tree, indigenous to South East Asia. Historically, the plant is locally used as a stimulant, a remedy in traditional medicine and in social context. Imported to Western countries, Kratom is classified as a novel psychoactive substance (NPS). A systematic review of the literature on Mitragyna speciosa and its main constituents was carried by our international multidisciplinary group. Results were qualitatively analysed in three main areas of interest: in-vitro and preclinical data on pharmacology and behavioral effects, laboratoristic techniques for identification/characterization, epidemiological/toxicological reports on humans. At present, there is no systematic data on the prevalence of Kratom use in all the native countries, but it seems to be considerable. In South-East Asia, Kratom, even if banned, might be still considered a better option than other illicit drugs, an alternative opioid treatment, a “natural” remedy with no real social stigma attached to its consumption. In parallel, this ethno-drug seems to be popular in Western countries, largely unregulated, easily available on the Internet. Kratom pharmacology appears to be complex, with many alkaloids involved. The subjective effects in humans are very peculiar and seem to be dose-dependent, ranging from psycho-stimulant to sedative-narcotic. Available data on Kratom suggest caution: this psychoactive plant could exhibit a serious harmful potential. Kratom use seems to be associated with drug dependency, development of withdrawal symptoms, craving, serious adverse effects and life-threatening effects in a multidrug-intoxicating scenario. On the other hand, its anxyiolitic, antidepressant and analgesic properties deserve to be further studied

Stability and Electronic Properties of TiO2 Nanostructures With and Without B and N Doping

We address one of the main challenges to TiO2-photocatalysis, namely band gap narrowing, by combining nanostructural changes with doping. With this aim we compare TiO2's electronic properties for small 0D clusters, 1D nanorods and nanotubes, 2D layers, and 3D surface and bulk phases using different approximations within density functional theory and GW calculations. In particular, we propose very small (R < 0.5 nm) but surprisingly stable nanotubes with promising properties. The nanotubes are initially formed from TiO2 layers with the PtO2 structure, with the smallest (2,2) nanotube relaxing to a rutile nanorod structure. We find that quantum confinement effects - as expected - generally lead to a widening of the energy gap. However, substitutional doping with boron or nitrogen is found to give rise to (meta-)stable structures and the introduction of dopant and mid-gap states which effectively reduce the band gap. Boron is seen to always give rise to n-type doping while depending on the local bonding geometry, nitrogen may give rise to n-type or p-type doping. For under coordinated TiO2 surface structures found in clusters, nanorods, nanotubes, layers and surfaces nitrogen gives rise to acceptor states while for larger clusters and bulk structures donor states are introduced