Properties of the integrated spectrum of serendipitous 2XMM catalogue sources

Our analysis is aimed at characterizing the properties of the integrated spectrum of active galactic nuclei (AGNs) such as the ubiquity of the Fe K{\alpha} emission in AGNs and the dependence of the spectral parameters on the X-ray luminosity and redshift. We selected 2646 point sources from the 2XMM catalogue at high galactic latitude (|BII| > 25 degrees) and with the sum of EPIC-PN and EPIC-MOS 0.2-12 keV counts greater than 1000. Redshifts were obtained for 916 sources from the NED. The final sample consists of 507 AGN. Individual source spectra have been summed in the observed frame to compute the integrated spectra in different redshift and luminosity bins over the range 0<z<5. Detailed analysis of these spectra has been performed. We find that the narrow Fe K{\alpha} line at 6.4 keV is significantly detected up to z=1. The line equivalent width decreases with increasing X-ray luminosity in the 2-10 keV band (''IT effect''). The anti-correlation is characterized by the relation log(EWFe) = (1.66 +/- 0.09) + (-0.43 +/- 0.07) log(LX,44), where EWFe is the rest frame equivalent width of the neutral iron K{\alpha} line in eV and LX,44 is the 2-10 keV X-ray luminosity in units of 10^{44} erg s^{-1}. The equivalent width is nearly independent of redshift up to z ~ 0.8 with an average value of 101+/-40 (rms dispersion) eV in the luminosity range 43.5<= logLX <= 44.5. Our analysis also confirmed the hardening of the spectral indices at low luminosities implying a dependence of obscuration on luminosity. We confirm that the neutral narrow Fe K{\alpha} line is an almost ubiquitous feature of AGNs. We find compelling evidence for the ''IT effect'' over a redshift interval larger than probed in any previous study. We detect no evolution of the average rest frame equivalent width of the Fe K{\alpha} line with redshift.Comment: 10 pages, 7 figures, 2 Tables. A&A in pres

Modelli interpretativi della distribuzione delle brughiere pedemontane ai fini gestionali.

Lo studio vuole contribuire alla conoscenza delle brughiere pedemontane a Calluna vulgaris (brugo) dell\u2019Italia settentrionale, ai fini di individuare elementi rilevanti per la gestione e la conservazione. L\u2019area di studio \ue8 compresa nella porzione collinare e planiziale della provincia di Como e in un breve tratto di quella di Milano. Sono stati impiegati i Generalized Linear Models per individuare quali tra le variabili ambientali interpretino pi\uf9 adeguatamente la distribuzione delle brughiere. Il modello finale indica un\u2019influenza positiva della geomorfologia (rilievi prealpini e depositi mindeliani), del bioclima (indice di Gams), della ricorrenza degli incendi e negativa del suolo (ultisols). La superficie potenzialmente occupata dalle brughiere corrisponde a circa il 7% del territorio attualmente a bosco, a prato oppure coltivato; tuttavia le brughiere si estendono oggi su meno dell\u20191% di questa superficie. La copertura della canopy influisce negativamente sulla presenza delle brughiere, con valori di Leaf Area Index tra 1.5-2.3, rilevanti una progressiva riduzione nella frequenza di brugo. Si desume pertanto il complessivo carattere relittuale di questo tipo di vegetazione, da ricollegarsi al diffuso abbandono della gestione tradizionale.Emerge in definitiva la necessit\ue0 di dare ampio impulso ad attivit\ue0 che sostengono la conservazione e il ripristino delle brughiere

Rest-frame stacking of 2XMM catalog sources : Properties of the Fe Kalpha line

The aim of this work is to characterize the average Fe K emission properties of active galactic nuclei (AGNs) in the source rest-frame. We selected a sample of 248 AGNs from the 2XMM catalog, covering a wide redshift range 0 < z < 5 and with the EPIC-PN net 2-10 keV rest-frame counts >=200 and power law photon indices in the range 1.5-2.2. We employed two fully independent rest-frame stacking procedures to compute the mean Fe K profile. The counting statistics for the integrated spectrum is comparable to the one available for the best studied local Seyferts. To identify the artifacts possibly introduced by the stacking procedure, we have carried out simulations. We report that the average Fe K line profile in our sample is best represented by a combination of a narrow and a broad line. The equivalent widths of the narrow and broad (parametrized with a diskline) components are ~30 eV and ~100 eV, respectively. We also discuss the results of more complex fits and the implications of the adopted continuum modeling on the broad line parameters and its detection significance.Comment: 13 pages, 13 figures, Accepted for publication in A&

Biomasse da praterie seminaturali come fonte di energia: un fuoco di paglia?

Biomass from seminatural grasslands as energy source: flash in the pan? - The aim of the study is to evaluate the potentiality of four seminatural herbaceous communities (grasslands of Arrhenatherion, Nardo-Agrostion tenuis, Bromion erecti and Polygono-Trisetion alliances) in the Prealpine Lombardy. We quantified the biomass production (stubble height 5 cm), the main bioenergetic features, such as ash, carbon, hydrogen and nitrogen content, and the Higher Heating Value. Biomass values vary greatly, with means between 513 (Arrhenatherion) to 227 g m-2 (Bromion erecti). The mean ash content ranges between 4.3-7.7% and mean HHV from 18.3 to 19.6 MJ kg-1. The mean energy per unit area varies between 4.5-9.5 MJ m-2.We suggest that the management of seminatural grasslands could provide biomass suitable for bioenergy production instead of common energy crops and at the same time promote conservation of habitats and their biodiversity, mostly in protected areas

Physical activity programs for balance and fall prevention in elderly: A systematic review

BACKGROUND: Due to demographic changes the world's population is progressively ageing. The physiological decay of the elderly adult may lead to a reduction in the ability to balance and an increased risk of falls becoming an important issue among the elderly. In order to counteract the decay in the ability to balance, physical activity has been proven to be effective. The aim of this study is to systematically review the scientific literature in order to identify physical activity programs able to increase balance in the elderly. METHODS: This review is based on the data from Medline-NLM, Pubmed, ScienceDirect, and SPORTDiscuss and includes randomized control trials that have analyzed balance and physical activity in healthy elderly over 65 years of age during the last decade. A final number of 8 manuscripts were included in the qualitative synthesis, which comprised 200 elderly with a mean age of 75.1 ± 4.4 years. The sample size of the studies varied from 9 to 61 and the intervention periods from 8 to 32 weeks. RESULTS: Eight articles were considered eligible and included in the quantitative synthesis. The articles investigated the effects of resistance and aerobic exercise, balance training, T-bow© and wobble board training, aerobic step and stability ball training, adapted physical activity and Wii Fit training on balance outcomes. Balance measures of the studies showed improvements between 16% and 42% compared to baseline assessments. CONCLUSIONS: Balance is a multifactorial quality that can be effectively increased by different exercise training means. It is fundamental to promote physical activity in the aging adult, being that a negative effect on balance performance has been seen in the no-intervention control groups

La vegetazione dell\u2019istituenda Riserva Naturale \u201cOasi di Lacchiarella\u201d (Parco Agricolo Sud Milano).

\uc8 stata studiata dal punto di vista fitosociologico la vegetazione della Riserva naturale Oasi di Lacchiarella. Sono state individuate 34 cenosi vegetali, ascrivibili a 12 classi fitosociologiche: Lemnetea, Potametea, Phragmiti-Magnocaricetea, Bidentetea tripartiti, Stellarietea mediae, Oryzetea sativae, Molinio- Arrhenatheretea,Galio-Urticetea, Alnetea glutinosae, Salicetea purpureae, Rhamno-Prunetea e Querco-Fagetea. Il grado di naturalit\ue0 e il valore floristico-vegetazionale \ue8 nel complesso basso, anche nelle formazioni boschive. Le cenosi si dispongono secondo un gradiente ecologico di umidit\ue0, caratterizzato da un progressivo svincolamento dalla falda. Le cenosi di piante infestanti o ruderali seguono una propria linea dinamico-evolutiva, pressoch\ue9 indipendente da quella di interramento dei corsi d\u2019acqua; entrambe comunque convergono verso le formazioni boschive

Finite elements prediction of thermal stresses in work roll of hot rolling mills

AbstractA simplified numerical approach based on finite elements to compute thermal stresses occurring in work roll of hot rolling mills is here proposed. To decrease both the complexity of the analysis and the computational effort, this approach implements a plane finite element model of the work roll alone, loaded on its surface by the rotating thermal actions due to the cyclic sequence of the conductive heating caused by the contact with hot strip and cooling provided by water jets. Results from thermal analysis are preliminary compared to an analytical solution available in the literature and then applied as thermal input in the subsequent mechanical finite elements simulations, which provide thermal stress in the work roll and the elastic-plastic evolution of elements, close to the work roll surface

Relevance of lactate level detection in migrane and fibromyalgia

The aim of this study was to determine the blood lactate levels in healthy and pathological subjects, particularly with migraine and fibromyalgia. Moreover we investigated the possible correlation between lactate concentration, postural stability and balance disorders; the composition of the groups were: migraine (n = 25; age 49.7 +/- 12.5), fibromyalgia (n = 10; age 43.7 +/- 21.2), control group (n = 16 age 28.52 +/- 2.4). The results showed that patients with fibromyalgia (FG) had higher lactate levels compared to migraine (MG) and control group (CG) (mean +/- sd: FG = 1.78 +/- 0.9 mmol/L; MG = 1.45 +/- 1 mmol/L; CG = 0,85 +/- 0,07 mmol/L). The same situation was highlighted about the sway path length with eyes closed (FG = 518 +/- 195 mm; MG = 465 +/- 165 mm; CG = 405 +/- 94,72 mm) and with eyes open (FG = 430 +/- 220 mm; MG = 411 +/- 143 mm; CG = 389 +/- 107 mm). This can be explained by the fact that energy-intensive postural strategies must be used to optimize both static and dynamic coordination, in particular with repeated contractions of tonic oxidative muscle cells responsible for postural control

Deep transfer learning for machine diagnosis: From sound and music recognition to bearing fault detection

Today’s deep learning strategies require ever‐increasing computational efforts and demand for very large amounts of labelled data. Providing such expensive resources for machine diagnosis is highly challenging. Transfer learning recently emerged as a valuable approach to address these issues. Thus, the knowledge learned by deep architectures in different scenarios can be reused for the purpose of machine diagnosis, minimizing data collecting efforts. Existing research provides evidence that networks pre‐trained for image recognition can classify machine vibrations in the time‐frequency domain by means of transfer learning. So far, however, there has been little discussion about the potentials included in networks pre‐trained for sound recognition, which are inherently suited for time‐frequency tasks. This work argues that deep architectures trained for music recognition and sound detection can perform machine diagnosis. The YAMNet convolutional network was designed to serve extremely efficient mobile applications for sound detection, and it was originally trained on millions of data extracted from YouTube clips. That framework is employed to detect bearing faults for the CWRU dataset. It is shown that transferring knowledge from sound and music recognition to bearing fault detection is successful. The maximum accuracy is achieved using a few hundred data for fine‐tuning the fault diagnosis model