Antimatter research in Space

Two of the most compelling issues facing astrophysics and cosmology today are to understand the nature of the dark matter that pervades the universe and to understand the apparent absence of cosmological antimatter. For both issues, sensitive measurements of cosmic-ray antiprotons and positrons, in a wide energy range, are crucial. Many different mechanisms can contribute to antiprotons and positrons production, ranging from conventional reactions up to exotic processes like neutralino annihilation. The open problems are so fundamental (i.e.: is the universe symmetric in matter and antimatter ?) that experiments in this field will probably be of the greatest interest in the next years. Here we will summarize the present situation, showing the different hypothesis and models and the experimental measurements needed to lead to a more established scenario.Comment: 10 pages, 7 figures, Invited talk at the 18th European Cosmic Ray Symposium, Moscow, July 2002, submitted to Journal of Physics

A reanalysis of the atmospheric boundary layer field experiment(SPCFLUX93) at San Pietro Capofiume (Italy)

A fortnight field experiment was carried out at San Pietro Capofiume(Po Valley, Italy)during the month of June, 1993, and was named SPCFLUX93. This location was chosen as representative of the Po Valley. The SPCFLUX93 experiment was devised according to the results of some previous measurements carried out in mountainous areas of South Europe (i.e. ALPEX—ALPine EXperiment, PYREX—PYRenean Experiment), and aimed to represent a prototype for further field observations. The dataset of the SPCFLUX93 experiment consisted of: i)meteorological and chemical data collected continuously with slow-response sensors in the atmospheric surface layer and into the soil; ii)data coming from fastresponse instrumentation (sonic anemometers and fluxmeter); iii) radiosoundings carried out with free and tethered balloons; iv)con tinuous vertical wind soundings with a Mini-Sodar. The aim of the SPCFLUX93 field experiment was to investigate the following topics: atmospheric turbulence, dry and wet atmospheric total deposition, energy balance, thermal wave propagation in the soil. Few years later, the atmospheric and hydrological scientific community conduced an extensive programme, the Mesoscale Alpine Programme (MAP), on weather and climate in mountainous regions. This programme considered many aspects of alpine meteorology, ranging from high-resolution numerical modelling to experimental campaigns performed on both sides of the Alps, with the aim to better understand the interaction processes of atmospheric fluxes with the orography. Many puzzling problems were posed by the complexity of these interactions; among them, the perturbations on the boundary layer structure caused by the airflows that cross the Alps and reach the Po Valley would still require more experimental observations and theoretical studies. These considerations prompted us to reanalyze the SPCFLUX93 dataset. In this paper, a layout of the field experiment (including the instrumentation details, the experimental relevant dataset and database composed by meteorological standard data, vertical profile data, ultrasonic anemometer data, and chemical data)is presented; the collected data are described; the details of the mesoscale meteorological situation over San Pietro Capofiume during the experiment are presented; finally, some analyses on the data are shown, and the main results coming from the several applications carried out using the dataset are illustrated or summarized. In particular, the most interesting results are related to the following topics: the characteristics of the turbulence in the surface layer (using the fast-response data), the validation of land surface schemes (using the surface observations), the evaluation of mixed layer depth (using radon flux data)and the estimate of deposition velocity

Anticoagulant pseudothrombocytopenia with platelet satellitism

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The primordial environment of super massive black holes: large scale galaxy overdensities around z∼6z\sim6 QSOs with LBT

We investigated the presence of galaxy overdensities around four $z\sim6$ QSOs, namely SDSS J1030+0524 (z = 6.28), SDSS J1148+5251 (z = 6.41), SDSS J1048+4637 (z = 6.20) and SDSS J1411+1217 (z = 5.95), through deep $r$-, $i$- and $z$- band imaging obtained with the wide-field ($\sim23'\times25'$) Large Binocular Camera (LBC) at the Large Binocular Telescope (LBT). We adopted color-color selections within the $i-z$ vs $r-z$ plane to identify samples of $i$-band dropouts at the QSO redshift and measure their relative abundance and spatial distribution in the four LBC fields, each covering $\sim8\times8$ physical Mpc at $z\sim6$. The same selection criteria were then applied to $z$-band selected sources in the $\sim$1 deg$^2$ Subaru-XMM Newton Deep Survey to derive the expected number of dropouts over a blank LBC-sized field ($\sim$0.14 deg$^2$). The four observed QSO fields host a number of candidates larger than what is expected in a blank field. By defining as $i$-band dropouts objects with $z_{AB}1.4$ and undetected in the $r$-band, we found 16, 10, 9, 12 dropouts in SDSS J1030+0524, SDSS J1148+5251, SDSS J1048+4637, and SDSS J1411+1217, respectively, whereas only 4.3 such objects are expected over a 0.14 deg$^2$ blank field. This corresponds to overdensity significances of 3.3, 1.9, 1.7, 2.5$\sigma$, respectively. By considering the total number of dropouts in the four LBC fields and comparing it with what is expected in four blank fields of 0.14 deg$^2$ each, we find that high-z QSOs reside in overdense environments at the $3.7\sigma$ level. This is the first direct and unambiguous measurement of the large scale structures around $z\sim6$ QSOs. [shortened]Comment: 12 pages, 8 figures. Accepted for publication in A&

Domestic heating: Can hemp-hurd derived pellet be an alternative?

Among the renewable sources, residual woody biomass from agricultural crops is becoming of great interest due to its lower environmental impact and one of the most growing agricultural sector, of the last decade, is the hemp industry which generates several kind of byproducts. In this paper, a blend of 50% of hemp-hurd and 50% of fir sawdust was pulverized and pelletized. The pellets were burned into a domestic pellet stove (9 kWth maximum nominal thermal power output) at different biomass flowrates. To compare results with a commercial-grade pellet, the tests were repeated by fueling the same stove with A2-grade pellets. Results shown that the pellet mixture 50/50 of fir sawdust and hemp-hurd is suitable for the commercial pellet stove used and that the slightly higher amount of ashes (2.7%), compared to pellet A2 (<1.2%), can be handled by the self-cleaning fire chamber. Comparable results were also obtained in regards with the stove global efficiency which ranged from 90.8-92.3% for the hemp pellets and 91-94% for the A2. A significant difference was noted in the biomass flowrate where, during the tests with hemp-hurd pellets a lower value was obtained (-20%) compared to A2. This resulted into lower power input in the stove and lower performances at the same nominal power output

Sustainable PHBV/CuS Composite Obtained from Waste Valorization for Wastewater Purification by Visible Light-Activated Photocatalytic Activity

The persistency of antimicrobial compounds in the water cycle accelerates the issue of antimicrobial resistance. Therefore, effective wastewater remediation approaches, which can be implemented on a large scale, are urgently required. This study aims at preparing a sustainable organic/inorganic composite material that can photo-catalyze the degradation of organic pollutants in wastewater by using visible light. Specifically, films and porous composites are composed of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) as supporting material, and copper sulfide (CuS) as active photocatalyst. It is noteworthy that the proposed composite can be fully produced from waste valorization, since PHBV is a polymer, which can be obtained by fermentation of vegetable wastes, and CuS is synthesized from industrial sulfur wastes. The produced composites show remarkable capabilities in the photodegradation of tetracycline and methylene blue, selected as model organic pollutants. Moreover, the PHBV/CuS composites can be reused multiple times with minimal loss in photocatalytic efficiency. The suggested approach is not only sustainable and cost-effective, but also solves issues occurring in the application of the photodegradation techniques currently reported, such as the consumption of fossil-based chemicals and photocatalyst removal from the purified water using with expensive procedures

Fully Biobased Polyhydroxyalkanoate/Tannin Films as Multifunctional Materials for Smart Food Packaging Applications

Fully biobased and biodegradable materials have attracteda growinginterest in the food packaging sector as they can help to reduce thenegative impact of fossil-based plastics on the environment. Moreover,the addition of functionalities to these materials by introducingactive molecules has become an essential requirement to create modernpackaging able to extend food's shelf-life while informingthe consumer about food quality and freshness. In this study, we presentan innovative bioplastic formulation for food packaging based on poly-(hydroxybutyrate-co-valerate) (PHBV) and tannins as multifunctional additives.As a proof of concept, PHBV/tannin films were prepared by solventcasting, increasing the tannin content from 1 to 10 per hundred ofresin (phr). Formic acid was used to reach a homogeneous distributionof the hydrophilic tannins into hydrophobic PHBV, which is remarkablychallenging by using other solvents. Thanks to their well-known properties,the effect of tannins on the antioxidant, UV protection, and gas barrierproperties of PHBV was evaluated. Samples containing 5 phr bioadditiverevealed the best combination of these properties, also maintaininggood transparency. Differential scanning calorimetry (DSC) investigationsrevealed that films are suitable for application from the fridge topotentially high temperatures for food heating (up to 200 degrees C).Tensile tests have also shown that Young's modulus (900-1030MPa) and tensile strength (20 MPa) are comparable with those of thecommon polymers and biopolymers for packaging. Besides the improvementof the PHBV properties for extending food's shelf-life, itwas also observed that PHBV/tannin could colorimetrically detect ammoniavapors, thus making this material potentially applicable as a smartindicator for food spoilage (e.g., detection of fish degradation).The presented outcomes suggest that tannins can add multifunctionalproperties to a polymeric material, opening up a new strategy to obtainan attractive alternative to petroleum-based plastics for smart foodpackaging applications

New sustainable routes for gas separation membranes: The properties of poly(hydroxybutyrate-co-hydroxyvalerate) cast from green solvents

The gas separation performance of biopolymers is still scarcely characterized, mostly because of their poor thermomechanical properties and high crystallinity which is associated to low permeability. In this work we characterize the gas transport in a poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) random copolymer, that has a relatively low crystallinity and good mechanical properties, combined with a renewable origin, biodegradability and biocompatibility. In the study we also compared several solvents for membrane casting, with different toxicity levels. We found that dimethyl carbonate allows the production of polymer films with transport properties similar to those obtained with the more toxic CHCl3, and it leads also to stable crystallinity of the samples over time. PHBV films show a size-sieving gas separation behaviour, as the permeability decreases significantly with the gas kinetic diameter. However, the strong energetic interactions of CO2 with the polymer matrix, confirmed by the Flory-Huggins model, induce a marked solubility-driven CO2/N2 and CO2/CH4 selectivity, which could make the material potentially interesting for CO2 removal processes

Gamma-ray observations of Cygnus X-1 above 100 MeV in the hard and soft states

We present the results of multi-year gamma-ray observations by the AGILE satellite of the black hole binary system Cygnus X-1. In a previous investigation we focused on gamma-ray observations of Cygnus X-1 in the hard state during the period mid-2007/2009. Here we present the results of the gamma-ray monitoring of Cygnus X-1 during the period 2010/mid-2012 carried out for which includes a remarkably prolonged `soft state' phase (June 2010 -- May 2011). Previous 1--10 MeV observations of Cyg X-1 in this state hinted at a possible existence of a non-thermal particle component with substantial modifications of the Comptonized emission from the inner accretion disk. Our AGILE data, averaged over the mid-2010/mid-2011 soft state of Cygnus X-1, provide a significant upper limit for gamma-ray emission above 100 MeV of F_soft < 20 x 10^{-8} ph/cm^2/s, excluding the existence of prominent non-thermal emission above 100 MeV during the soft state of Cygnus X-1. We discuss theoretical implications of our findings in the context of high-energy emission models of black hole accretion. We also discuss possible gamma-ray flares detected by AGILE. In addition to a previously reported episode observed by AGILE in October 2009 during the hard state, we report a weak but important candidate for enhanced emission which occurred at the end of June 2010 (2010-06-30 10:00 - 2010-07-02 10:00 UT) exactly in coincidence with a hard-to-soft state transition and before an anomalous radio flare. An appendix summarizes all previous high-energy observations and possible detections of Cygnus X-1 above 1 MeV.Comment: 16 pages, 12 figures, 1 table, accepted for publication in Ap