1,000 research outputs found
Follow-up observations of X-ray emitting hot subdwarf star: the He-rich sdO BD +37{\deg} 1977
We report on the results of the first XMM-Newton satellite observation of the
luminous and helium-rich O-type subdwarf BD +37{\deg} 1977 carried out in April
2014. X-ray emission is detected with a flux of about 4*10^(-14) erg/cm2/s
(0.2-1.5 keV), corresponding to a f_X/f_bol ratio about 10^(-7); the source
spectrum is very soft, and is well fit by the sum of two plasma components at
different temperatures. Both characteristics are in agreement with what is
observed in the main-sequence early-type stars, where the observed X-ray
emission is due to turbulence and shocks in the stellar wind. A smaller but
still significant stellar wind has been observed also in BD +37{\deg} 1977;
therefore, we suggest that also in this case the detected X-ray flux has the
same origin.Comment: 6 pages. Accepted for publication by Astronomy and Astrophysic
Effect of morphology and defectiveness of graphene-related materials on the electrical and thermal conductivity of their polymer nanocomposites
In this work, electrically and thermally conductive poly (butylene
terephthalate) nanocomposites were prepared by in-situ ring-opening
polymerization of cyclic butylene terephthalate (CBT) in presence of a
tin-based catalyst. One type of graphite nanoplatelets (GNP) and two different
grades of reduced graphene oxide (rGO) were used. Furthermore, high temperature
annealing treatment under vacuum at 1700{\deg}C was carried out on both RGO to
reduce their defectiveness and study the correlation between the
electrical/thermal properties of the nanocomposites and the nanoflakes
structure/defectiveness. The morphology and quality of the nanomaterials were
investigated by means of electron microscopy, x-ray photoelectron spectroscopy,
thermogravimetry and Raman spectroscopy. Thermal, mechanical and electrical
properties of the nanocomposites were investigated by means of rheology,
dynamic mechanical thermal analysis, volumetric resistivity and thermal
conductivity measurements. Physical properties of nanocomposites were
correlated with the structure and defectiveness of nanoflakes, evidencing a
strong dependence of properties on nanoflakes structure and defectiveness. In
particular, a significant enhancement of both thermal and electrical
conductivities was demonstrated upon the reduction of nanoflakes defectiveness
Effect of processing conditions on the thermal and electrical conductivity of poly (butylene terephthalate) nanocomposites prepared via ring-opening polymerization
Successful preparation of polymer nanocomposites, exploiting graphene-related
materials, via melt mixing technology requires precise design, optimization and
control of processing. In the present work, the effect of different processing
parameters during the preparation of poly (butylene terephthalate)
nanocomposites, through ring-opening polymerization of cyclic butylene
terephthalate in presence of graphite nanoplatelets (GNP), was thoroughly
addressed. Processing temperature (240{\deg}C or 260{\deg}C), extrusion time (5
or 10 minutes) and shear rate (50 or 100 rpm) were varied by means of a full
factorial design of experiment approach, leading to the preparation of
polybutylene terephthalate/GNP nanocomposite in 8 different processing
conditions. Morphology and quality of GNP were investigated by means of
electron microscopy, X-ray photoelectron spectroscopy, thermogravimetry and
Raman spectroscopy. Molecular weight of the polymer matrix in nanocomposites
and nanoflake dispersion were experimentally determined as a function of the
different processing conditions. The effect of transformation parameters on
electrical and thermal properties was studied by means of electrical and
thermal conductivity measurement. Heat and charge transport performance
evidenced a clear correlation with the dispersion and fragmentation of the GNP
nanoflakes; in particular, gentle processing conditions (low shear rate, short
mixing time) turned out to be the most favourable condition to obtain high
conductivity values
Perfectionism or Perfectionisms in Orthorexia Nervosa
Purpose: Perfectionism is considered a transdiagnostic construct that characterises eating disorders (EDs) and obsessive-compulsive disorder (OCD) and that could also depict orthorexia nervosa (ON). The principal aim of this study was to investigate what dimensions of perfectionism mostly represent ON. Moreover, it was evaluated if dieting impacted the presence of orthorexic features and perfectionistic behaviour. Methods: The sample consisted of two groups-the "Diet" (n = 93), and the "No Diet" (n = 94) groups-composed of people with high and low orthorexic tendencies, respectively. Participants filled out self-report questionnaires to investigate orthorexic tendencies and different facets of perfectionism. Results: Analyses highlighted that people with high orthorexic tendencies showed higher perfectionistic features and that ON had a significant relationship with different facets of perfectionism. No interactions with diet were found. Therefore, no other differences were highlighted when the group type (Diet/No Diet) was considered. Conclusions: Regardless of diet, different facets of perfectionism characterise ON: perfectionism as a personality trait and perfectionism related to EDs and to obsessive-compulsive features. Our results evidenced that perfectionism could also be considered a useful construct in the conceptualization of orthorexia nervosa
New trends in teacher\u2019s education. Educational placement of the adopted child
In Italy, the number of adopted school-age children is increasing. According to the Commission of Intercountry Adoption (2013),
3106 children were adopted, 47.5% of them are between 5 and 9 years old. The present action-research aims at exploring the
spread of good approaches in schools in terms of welcoming of adopted children. For this purpose, 268 teachers of primary
schools were involved in analyzing the social representation about adopted children and their family. The results show a
simplified vision of the adoptive family, which is described as heroic family or, on the contrary, as a family with difficulty
Soil carbon budget account for the sustainability improvement of a Mediterranean vineyard area
Sustainable viticulture is suggested as an interesting strategy for achieving the objectives of global greenhouse gas (GHG) emission reduction in terms of mitigation and adaptation. However, knowledge and quantification of the contribution of sustainable vineyard management on climate change impact are needed. Although it is widely assessed by several authors that the agricultural stage has a great impact in the wine chain, very few studies have evaluated the greenhouse gas emission in this phase including the ability of soil to sequester carbon (C) or the off-farm C loss by erosion. This work aimed to provide a vineyard carbon budget (vCB) tool to quantify the impact of grape production on GHG emission including the effects of environmental characteristics and agricultural practices. The vCB was estimated considering four different soil management scenarios: conventional tillage (CT), temporary cover crop with a leguminous species in alternate inter-rows (ACC), temporary cover crop with a leguminous species (CC), permanent cover crop (PCC). The estimation of vCB was applied at territory level in a viticulture area in Sicily (2468 ha of vineyard) using empirical data. Results of the present study showed that the environmental characteristics strongly affect the sustainability of vineyard management; the highest contribution to total CO2 emission is, in fact, given by the C losses by erosion in sloping vineyards. Soils of studied vineyards are a source of CO2 due to the low C inputs and high mineralization rate, except for soil managed by CC which can sequester soil C, contributing positively to vCB. The highest total CO2 emission was estimated in vineyards under CT management (2.31 t ha−1y−1), followed by CC (1.27 t ha−1y−1), ACC (0.69 t ha−1y−1) and PCC (0.64 t ha−1y−1). Findings of vCB applied at territory level highlighted the key role of the evaluation of carbon budget (CB) on a larger scale to identify the CO2 emission in relation to climatic and environmental factors. The present study could contribute to provide suggestions to policymakers and farmers for reducing GHG emissions and promote more sustainable grape production practices
Understanding the role of soil erosion on co2-c loss using 13c isotopic signatures in abandoned Mediterranean agricultural land
Understanding soil water erosion processes is essential to evaluate the redistribution of soil organic carbon (SOC) within a landscape and is fundamental to assess the role of soil erosion in the global carbon (C) budget. The main aim of this study was to estimate the C redistribution and losses using 13C natural abundance. Carbon losses in soil sediment, dissolved organic carbon (DOC) and CO2 emission were determined. Four bounded parallel plots were installed on a 10% slope. In the upper part of the plots, C3soil was replaced with C4soil. The SOC and δ13C were measured after 145.2 mm rainfall in the upper (2 m far from C4strip), middle (4 m far from C4strip) lower (6 m far from C4strip) trams of the plot and in the sediments collected in the Gerlach collector at the lower part of the plot. A laboratory incubation experiment was performed to evaluate the CO2 emission rate of soils in each area. OC was mainly lost in the sediments as 2.08 g−2 of C was lost after 145.2 mm rainfall. DOC losses were only 5.61% of off-site OC loss. Three months after the beginning of the experiment, 15.90% of SOC in the upper tram of the plot had a C4 origin. The C4-SOC content decreased along the 6 m length of the plot, and in the sediments collected by the Gerlach collector. CO2 emission rate was high in the upper plot tram due to the high SOC content. The discrimination of CO2 in C3 and C4 portion permitted to increase our level of understanding on the stability of SOC and its resilience to decomposition. The transport of sediments along the plot increased SOC mineralization by 43%. Our study underlined the impact of rainfall in C losses in soil and water in abandoned Mediterranean agriculture fields and the consequent implications on the C balance
Protein cargo of salivary small extracellular vesicles as potential functional signature of oral squamous cell carcinoma
The early diagnosis of oral squamous cell carcinoma (OSCC) is still an investigative challenge. Saliva has been proposed as an ideal diagnostic medium for biomarker detection by mean of liquid biopsy technique. The aim of this pilot study was to apply proteomic and bioinformatic strategies to determine the potential use of saliva small extracellular vesicles (S/SEVs) as a potential tumor biomarker source. Among the twenty-three enrolled patients, 5 were free from diseases (OSCC_FREE), 6 were with OSCC without lymph node metastasis (OSCC_NLNM), and 12 were with OSCC and lymph node metastasis (OSCC_LNM). The S/SEVs from patients of each group were pooled and properly characterized before performing their quantitative proteome comparison based on the SWATH_MS (Sequential Window Acquisition of all Theoretical Mass Spectra) method. The analysis resulted in quantitative information for 365 proteins differentially characterizing the S/SEVs of analyzed clinical conditions. Bioinformatic analysis of the proteomic data highlighted that each S/SEV group was associated with a specific cluster of enriched functional network terms. Our results highlighted that protein cargo of salivary small extracellular vesicles defines a functional signature, thus having potential value as novel predict biomarkers for OSCC
- …