Firm Opacity Lies in the Eye of the Beholder

We classify and test empirical measures of firm opacity and document theoretical and empirical inconsistencies across these proxies by testing the relative opacity of banks versus non-banks. We evaluate the effectiveness of these proxies by observing the effect of two cleanly identified shocks to firm-specific information: credit rating initiation and inclusion in the S&P 500 index. Using a difference-in-difference approach, we compare firms that are newly rated and firms that are included in the S&P 500 index with a propensity matched sample of “unchanged” firms. We find that only the number of analysts and Amihud's illiquidity ratio provide consistent patterns across different estimation specifications and different econometric settings. These two proxies show that banks are more opaque than non-banks. Based on our tests, we recommend that these proxies be used as the primary measures of firm opacity

Principali patogeni e difesa

Olive as other woody perennial crops can be affected by several systemic pathogens, including bacteria, fungi and several vector-borne viruses. The most important olive diseases, caused by different pathogens, are described in this text. Pathogen biology, diagnostic technique and control strategies are reported for each disease. The main and widespread bacterial disease, caused by Pseudomonas savastanoi pv. savastanoi, is the olive knot. As concerns the most important and widespread fungal diseases, in this text are described the olive leaf spot, Verticillum wilt, cercosporiosis, anthracnose, fruit rot, parasitic brusca, root rot, sooty mold and wood rot. Infections caused by viruses are generally symptomless and do not result in diseased plants. Although, viruses do not cause detrimental disease on olive varieties, the infected olive trees represent a reservoir of virus inoculum for other crops, where these viruses are known to cause severe disease. Detection of these viruses represent an important critical step in the sanitary improvement of this crop. Recently, molecularbased assays have been effectively implemented to detect at least 8 of the 15 viruses known to infect this crop. Sanitation program using in vitro culture of shoot tip and thermotherapy have been recently described to recover virus-free plantlets.Realizzato nell'ambito del progetto "Ricerca ed Innovazione per l'Olivicoltura Meridionale", finanziato dal MiPAAFMiPAAF - Ministero delle politiche agricole alimentari e forestal

Supercritical water gasification of waste oils as a source of syngas

A huge amount of waste oil is produced worldwide. Also substantial amount of virgin oils is available that are interesting candidates for upgrading into syngas. Supercritical water gasification (SCWG) can be considered as an aqueous phase reforming process to produce syngas from oils. In this work, a variety of waste and virgin oils were gasified in a continuous down-flow autoclave reactor at supercritical conditions. Experiments were carried out at 430 °C and 660 °C, 25 MPa, with a residence time in the range 103-170 s, in order to investigate gasification and carbon efficiency, hydrogen yield and composition of the produced gas. All the analysed feedstocks were suspended in water at various concentrations before gasification. Pyrolysis bio-oil showed a gasification efficiency of 74 % and 86 % for mixtures with 3 and 10 oil/water wt ratio, respectively. Waste motor oil, suspended in water at a concentration of 1 % wt thanks to the use of surfactants, was successfully gasified with a gasification efficiency of 73 %. Virgin motor oil gasification efficiency higher than 60% had been obtained for both analysed concentrations (5 % wt and 10 % wt of oil). Gasification of rapeseed oil at 5 % wt showed a gasification efficiency close to 88 %. On the contrary, the gasification of sunflower oil at 430 °C showed that this temperature is not high enough to obtain acceptable gasification efficiencies that varied from 20 % to 15 % for concentrations of oil from 2 % wt to 8 % wt, respectively. The analysis of the gas composition, in all the studied cases, showed that the obtained gas stream was rich in H2, CH4 and CO2, with variable quantities of light hydrocarbons (C2H4, C2H6 and C3H8)

A mechanical analysis of variable angle-tow composite plates through variable kinematics models based on Carrera’s unified formulation

Variable Angle-Tow (VAT) laminates offer a promising alternative to straight fiber composites. By varying fibers orientation within the structure plane, ambitious design and performance goals can be achieved. However, the wider design space results in a more complex problem with more parameters to consider. Carrera’s Unified Formulation (CUF) has been used in previous works performing buckling, vibrational and stress analyses of VAT plates. Usually, one-dimensional (1D) CUF beam models are used, while two-dimensional (2D) plate models are obtained as a particular case of shells by considering a null curvature. In most cases, a linear law is considered to describe the variation of fibers orientation in the main plane of the structure. The purpose of this article is to extend the CUF 2D plate finite elements family to the mechanical analysis of composite laminated plate structures with curvilinear fibers. The main contribute consists in the development of a CUF FE model within the Reissner’s Mixed Variational Theorem (RMVT) context for an improved calculation of the out-of-plane stress components. Results show that RMVT can predict in-plane stresses and satisfy the though-the-thickness transverse stresses continuity due to inter-layer equilibrium. The accuracy of RMVT-based models is also investigated using two different approximation points distributions along the plates thickness

Nanomolar detection of the antitumor drug tamoxifen by flexible organic electrochemical devices

Organic Electrochemical Transistors (OECTs) represent a versatile tool successfully exploited in the field of Bioelectronics. In particular, OECTs have been used for the detection of a wide set of bioanalytes, often showing superior performance compared to that of commonly used sensors. In this study, we propose a flexible, disposable OECT, based on poly (3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) channels and few layers graphene (FLG) sheets gate electrodes, for the detection of Tamoxifen (TAM), an important antitumor drug widely used in breast cancer therapy. The optimal device operation conditions in terms of sensitivity and limit of detection (LOD) have been investigated too

PEDOT:PSS Morphostructure and ion-to-electron transduction and amplification mechanisms in organic electrochemical transistors

Organic electrochemical transistors (OECTs) represent a powerful and versatile type of organic-based device, widely used in biosensing and bioelectronics due to potential advantages in terms of cost, sensitivity, and system integration. The benchmark organic semiconductor they are based on is poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), the electrical properties of which are reported to be strongly dependent on film morphology and structure. In particular, the literature demonstrates that film processing induces morphostructural changes in terms of conformational rearrangements in the PEDOT:PSS in-plane phase segregation and out-of-plane vertical separation between adjacent PEDOT-rich domains. Here, taking into account these indications, we show the thickness-dependent operation of OECTs, contextualizing it in terms of the role played by PEDOT:PSS film thickness in promoting film microstructure tuning upon controlled-atmosphere long-lasting thermal annealing (LTA). To do this, we compared the LTA-OECT response to that of OECTs with comparable channel thicknesses that were exposed to a rapid thermal annealing (RTA). We show that the LTA process on thicker films provided OECTs with an enhanced amplification capability. Conversely, on lower thicknesses, the LTA process induced a higher charge carrier modulation when the device was operated in sensing mode. The provided experimental characterization also shows how to optimize the OECT response by combining the control of the microstructure via solution processing and the effect of postdeposition processing

A novel phytocannabinoid isolated from Cannabis sativa L. with an in vivo cannabimimetic activity higher than \u3949-tetrahydrocannabinol: \u3949-Tetrahydrocannabiphorol

(-)-Trans-Delta(9)-tetrahydrocannabinol (Delta(9)-THC) is the main compound responsible for the intoxicant activity of Cannabis sativa L. The length of the side alkyl chain influences the biological activity of this cannabinoid. In particular, synthetic analogues of Delta(9)-THC with a longer side chain have shown cannabimimetic properties far higher than Delta(9)-THC itself. In the attempt to define the phytocannabinoids profile that characterizes a medicinal cannabis variety, a new phytocannabinoid with the same structure of Delta(9)-THC but with a seven-term alkyl side chain was identified. The natural compound was isolated and fully characterized and its stereochemical configuration was assigned by match with the same compound obtained by a stereoselective synthesis. This new phytocannabinoid has been called (-)-trans-Delta(9)-tetrahydrocannabiphorol (Delta(9)-THCP). Along with Delta(9)-THCP, the corresponding cannabidiol (CBD) homolog with seven-term side alkyl chain (CBDP) was also isolated and unambiguously identified by match with its synthetic counterpart. The binding activity of Delta(9)-THCP against human CB1 receptor in vitro (K-i = 1.2 nM) resulted similar to that of CP55940 (K-i = 0.9 nM), a potent full CB1 agonist. In the cannabinoid tetrad pharmacological test, Delta(9)-THCP induced hypomotility, analgesia, catalepsy and decreased rectal temperature indicating a THC-like cannabimimetic activity. The presence of this new phytocannabinoid could account for the pharmacological properties of some cannabis varieties difficult to explain by the presence of the sole Delta(9)-THC

Aerosol Jet Printed Organic Memristive Microdevices Based on a Chitosan:PANI Composite Conductive Channel

In this study we show a chitosan:polyaniline (CPA)-based ink, responding to eco-biofriendly criteria, specifically developed for the manufacturing of the first organic memristive device (OMD) with an aerosol jet printed conductive channel. Our contribution is in the context of bioelectronics, where there is an increasing interest in emulating neuro-morphic functions. In this framework, memristive devices and systems have been shown to be well suited. In particular organic-based devices are envisaged as very promising in some applications, such as brain-machine interfacing, owing to specific properties of organics (e.g., biocompatibility, mixed ionic-electronic conduction). On the other hand, the research activities on flexible organic (bio)electronic devices and direct writing (DW) noncontact techniques increasingly overlap in the effort of achieving reliable applications benefiting from the rapid prototyping to accomplish a fast device optimization. In this context, ink-based techniques, such as aerosol jet printing (AJP), although particularly well suited to implement 3D-printed electronics due to advantages it offers in terms of a wide set of allowed printable materials, still require research efforts aimed at conferring printability to the desired precursors. The developed CPA composite was characterized by FTIR, DLS, and MALDI-TOF techniques, while the related aerosol jet printed films were studied by SEM and profilometry. Taking advantage of the intrinsic and stable electrical conductivity of CPA films, which do not necessarily require any acidic treatment to promote a sustained charge carrier conduction, 10 mu m short-channel OMDs were hence manufactured by interfacing the printed CPA layers with a solid polyelectrolyte (SPE). We accordingly demonstrated prototypes of stable and best performing OMD devices with downscaled features, showing well-defined counterclockwise hysteresis/rectification and an enhanced durability. These properties pave the way to further improving performance, as well as to realizing a direct integration of the devices into hardware neural networks by in-line fabrication routes