Interpreting the simultaneous variability of near-IR continuum and line emission in young stellar objects

We present new near-infrared (IR) spectra (0.80-1.35um) of the pre-Main Sequence source PV Cep taken during a monitoring program of eruptive variables we are conducting since some years. Simultaneous photometric and spectroscopic observations are systematically carried out during outburst and quiescence periods. By correlating extinction-free parameters, such as HI recombination lines and underlying continuum, it is possible to infer on the mechanism(s) responsible for their origin. Accretion and mass loss processes have a dominant role in determining the PV Cep irregular variability of both continuum and line emission. The potentialities of the observational modality are also discussed.Comment: accepted by Astrophysics and Space Scenc

MTG: resolution enhancement for MW measurements from geostationary orbits

The purpose of this study is to develop and evaluate image processing techniques that improve the spatial resolution of the channels already selected in the preliminary studies for "Geostationary Observatory for Microwave Atmospheric Soundings (GOMAS)". Reference high resolution multifrequency brightness temperatures scenarios have been derived by applying radiative transfer calculation to the spatially and microphysically detailed output of meteorological events simulated by the University of Wisconsin - Non-hydrostatic Model System. Two approaches, Wiener filter and SIR algorithm, have been applied to low frequency channels to enhance the resolution of antenna temperatures, exploiting the oversampling available for GOMAS channels observational strategy. Quite similar improvements have been obtained by applying the two techniques, even if SIR algorithm has provided generally better performances at computation time's expense

Image Based Modeling Technique for Pavement Distress surveys: a Specific Application to Rutting

Image-based modeling (IBM) is a well-known technique to obtain high quality 3D models based on multi view images. IBM started being used in several applications such as inspection, identification of objects and visualization, due to the user-friendly approach, the low cost and highly automated technique. This paper focuses on the investigation of the potential application of IBM in the diagnosis of road pavement distresses and in particular rutting. Indeed, the evaluation of the rutting distress is a fundamental step to define the whole state of a pavement as demonstrated by the calculation of Present Serviceability Index (PSI). Currently, the permanent deformation is measured monitoring visually the rut depth with the approximations that this procedure involves. Nevertheless, the exact measure of the rut depth is necessary to evaluate precisely the cause and the severity of this distress and be effective in the maintenance and rehabilitation of the pavement structure. The objective of this study is to apply the IBM technique on a laboratory rutted sample, in order to verify the accuracy of the method in determining the rut depth. To achieve this, a comparison has been made between the 3D model obtained with IBM and the one obtained with blue led 3D scan (Artec Spider) of the same rutted asphalt concrete. The metric accuracy of the model is then defined and its validity is assessed, in terms of distress diagnosis

Evidence for T Tauri-like emission in the EXor V1118 Ori from near-IR and X-ray data

We present a near-IR study of the EXor variable V1118 Ori, performed by following a slightly declining phase after a recent outburst. In particular, the near-IR (0.8 - 2.3 micron) spectrum, obtained for the first time, shows a large variety of emission features of the HI and HeI recombination and CO overtone. By comparing the observed spectrum with a wind model, a mass loss rate value is derived along with other parameters whose values are typical of an accreting T Tauri star. In addition, we have used X-ray data from the XMM archive, taken in two different epochs during the declining phase monitored in IR. X-ray emission (in the range 0.5 - 10 keV) permits to derive several parameters which confirm the T Tauri nature of the source. In the near-IR the object maintains a low visual extinction during all the activity phases, confirming that variable extinction does not contribute to brightness variations. The lack of both a significant amount of circumstellar material and any evidence of IR cooling from collimated jet/outflow driven by the source, indicates that, at least this member of the EXor class, is in a late stage of the Pre-Main Sequence evolution. In the X-ray regime, an evident fading is present, detected in the post-outburst phase, that cannot be reconciled with the presence of any absorbing material. This circumstance, combined with the persistence (in the pre- and post-outburst phases) of a temperature component at about 10 MK, suggests that accretion has some influence in regulating the coronal activity

Does degradation from selective logging and illegal activities differently impact forest resources? A case study in Ghana

Degradation, a reduction of the ecosystem’s capacity to supply goods and services, is widespread in tropical forests and mainly caused by human disturbance. To maintain the full range of forest ecosystem services and support the development of effective conservation policies, we must understand the overall impact of degradation on different forest resources. This research investigates the response to disturbance of forest structure using several indicators: soil carbon content, arboreal richness and biodiversity, functional composition (guild and wood density), and productivity. We drew upon large field and remote sensing datasets from different forest types in Ghana, characterized by varied protection status, to investigate impacts of selective logging, and of illegal land use and resources extraction, which are the main disturbance causes in West Africa. Results indicate that functional composition and the overall number of species are less affected by degradation, while forest structure, soil carbon content and species abundance are seriously impacted, with resources distribution reflecting the protection level of the areas. Remote sensing analysis showed an increase in productivity in the last three decades, with higher resiliency to change in drier forest types, and stronger productivity correlation with solar radiation in the short dry season. The study region is affected by growing anthropogenic pressure on natural resources and by an increased climate variability: possible interactions of disturbance with climate are also discussed, together with the urgency to reduce degradation in order to preserve the full range of ecosystem functions

Myrtucommulone from Myrtus communis exhibits potent anti-inflammatory effectiveness in vivo.

Myrtucommulone a nonprenylated acylphloroglucinol contained in the leaves of myrtle (Myrtus communis), has been reported to suppress the biosynthesis of eicosanoids by inhibition of 5-lipoxygenase and cyclooxygenase-1 in vitro and to inhibit the release of elastase and the formation of reactive oxygen species in activated polymorphonuclear leukocytes. Here, in view of the ability of MC to suppress typical proinflammatory cellular responses in vitro, we have investigated the effects of MC in in vivo models of inflammation. MC was administered to mice intraperitoneally, and paw edema and pleurisy were induced by the subplantar and intrapleural injection of carrageenan, respectively. MC (0.5, 1.5, and 4.5 mg/kg i.p.) reduced the development of mouse carrageenan-induced paw edema in a dose-dependent manner. Moreover, MC (4.5 mg/kg i.p. 30 min before and after carrageenan) exerted anti-inflammatory effects in the pleurisy model. In particular, 4 h after carrageenan injection in the pleurisy model, MC reduced: 1) the exudate volume and leukocyte numbers; 2) lung injury (histological analysis) and neutrophil infiltration (myeloperoxidase activity); 3) the lung intercellular adhesion molecule-1 and P-selectin immunohistochemical localization; 4) the cytokine levels (tumor necrosis factor-α and interleukin-1 β in the pleural exudate and their immunohistochemical localization in the lung; 5) the leukotriene B 4, but not prostaglandin E2, levels in the pleural exudates; and 6) lung peroxidation (thiobarbituric acid-reactant substance) and nitrotyrosine and poly (ADP-ribose) immunostaining. In conclusion, our results demonstrate that MC exerts potent anti-inflammatory effects in vivo and offer a novel therapeutic approach for the management of acute inflammation. Copyright © 2009 by The American Society for Pharmacology and Experimental Therapeutics

On the 2015 outburst of the EXor variable star V1118 Ori

After a long-lasting period of quiescence of about a decade, the source V1118 Ori, one of the most representative members of the EXor variables, is now outbursting. Since the initial increase of the near-infrared flux of about 1 mag (JHK bands) registered on 2015 September 22, the source brightness has remained fairly stable. We estimate DeltaV about 3 mag with respect to the quiescence phase. An optical/near-IR low-resolution spectrum has been obtained with the Large Binocular Telescope instruments MODS and LUCI2, and compared with a spectrum of similar spectral resolution and sensitivity level taken during quiescence. Together with the enhancement of the continuum, the outburst spectrum presents a definitely higher number of emission lines, in particular HI recombination lines of the Balmer, Paschen, and Brackett series, along with bright permitted lines of several species, forbidden atomic lines, and CO ro-vibrational lines. Both mass accretion and mass loss rates have significantly increased (by to about an order of magnitude, mass accretion rate = 1.2-4.8 10^-8 M_sun/yr, mass loss rate = 0.8-2 10^-9 M_sun/yr) with respect to the quiescence phase. If compared with previous outbursts, the present one appears less energetic. Alternatively, it could already be in the fading phase (with the maximum brightness level reached when the source was not visible), or, viceversa, still in the rising phase.Comment: Accepted ApJ Letter

A long-lasting quiescence phase of the eruptive variable V1118 Ori

V1118 Ori is an eruptive variable belonging to the EXor class of Pre-Main Sequence stars whose episodic outbursts are attributed to disk accretion events. Since 2006, V1118 Ori is in the longest quiescence stage ever observed between two subsequent outbursts of its recent history. We present near-infrared photometry of V1118 Ori carried out during the last eight years, along with a complete spectroscopic coverage from 0.35 to 2.5 um. A longterm sampling of V1118 Ori in quiescence has never been done, hence we can benefit from the current circumstance to determine the lowest values (i.e. the zeroes) of the parameters to be used as a reference for evaluating the physical changes typical of more active phases. A quiescence mass accretion rate between 1--3 $\times$ 10$^{-9}$ M_{\sun} yr$^{-1}$ can be derived and the difference with previous determinations is discussed. From line emission and IR colors analysis a visual extinction of 1-2 mag is consistently derived, confirming that V1118 Ori (at least in quiescence) is a low-extinction T Tauri star with a bolometric luminosity of about 2.1 L_{\sun}. An anti-correlation exists between the equivalent width of the emission lines and the underlying continuum. We searched the literature for evaluating whether or not such a behaviour is a common feature of the whole class. The anti-correlation is clearly recognizable for all the available EXors in the optical range (H$\beta$ and H$\alpha$ lines), while it is not as much evident in the infrared (Pa$\beta$ and Br$\gamma$ lines). The observed anti-correlation supports the accretion-driven mechanism as the most likely to account for continuum variations.Comment: 6 figures, 5 tables, accepted on Ap

Protective role of PI3-kinase-Akt-eNOS signalling pathway in intestinal injury associated with splanchnic artery occlusion shock.

Background and purpose: Endothelial NO synthase (eNOS) is a dynamic enzyme tightly controlled by co- and post-translational lipid modifications, phosphorylation and regulated by protein-protein interactions. Here we have pharmacologically modulated the activation of eNOS, at different post-translational levels, to assess the role of eNOS-derived NO and of these regulatory mechanisms in intestinal injury associated with splanchnic artery occlusion (SAO) shock. Experimental approach: SAO shock was induced by clamping both the superior mesenteric artery and the celiac trunk for 45 min followed by 30 min of reperfusion. During ischemia, 15 min prior to reperfusion, mice were given geldanamycin, an inhibitor of hsp90 recruitment to eNOS, or LY-294002 an inhibitor of phosphatidylinositol 3-kinase (PI3K), an enzyme that initiates Akt-catalysed phosphorylation of eNOS on Ser 1179. After 30 min of reperfusion, samples of ileum were taken for histological examination or for biochemical studies. Key results: Either LY-294002 or geldanamycin reversed the increased activation of eNOS and Akt observed following SAO shock. These molecular effects were mirrored in vivo by an exacerbation of the intestinal damage. Histological damage also correlated with neutrophil infiltration, assessed as myeloperoxidase activity, and with an increased expression of the adhesion proteins: ICAM-I, VCAM, P-selectin and E-selectin. Conclusions and implications: Overall these results suggest that activation of the Akt pathway in ischemic regions of reperfused ileum is a protective event, triggered in order to protect the intestinal tissue from damage induced by ischaemia/reperfusion through a fine tuning of the endothelial NO pathway. © 2007 Nature Publishing Group All rights reserved

Up-regulation of prostaglandin biosynthesis by leukotriene C4 in elicited mice peritoneal macrophages activated with lipopolysaccharide/interferon-gamma

Leukotrienes (LT) and prostaglandins (PG) are proinflammatory mediators generated by the conversion of arachidonic acid via 5-lipoxygenase (5-LO) and cyclooxygenase (COX) pathways. It has long been proposed that the inhibition of the 5-LO could enhance the COX pathway leading to an increased PG generation. We have found that in in vitro models of inflammation, such as mice-elicited peritoneal macrophages activated with lipopolysaccharide (LPS)/interferon- γ (IFN-γ), the deletion of the gene encoding for 5-LO or the enzyme activity inhibition corresponded to a negative modulation of the COX pathway. Moreover, exogenously added LTC4, but not LTD4, LTE 4, and LTB4, was able to increase PG production in stimulated cells from 5-LO wild-type and knockout mice. LTC4 was not able to induce COX-2 expression by itself but rather potentiated the action of LPS/IFN-γ through the extracellular signal-regulated kinase-1/2 activation, as demonstrated by the use of a specific mitogen-activated protein kinase (MAPK) kinase inhibitor. The LT-induced increase in PG generation, as well as MAPK activation, was dependent by a specific ligand-receptor interaction, as demonstrated by the use of a cys-LT1 receptor antagonist, although also a direct action of the antagonist used, on PG generation, cannot be excluded. Thus, the balance between COX and 5-LO metabolites could be of great importance in controlling macrophage functions and consequently, inflammation and tumor promotion