36 research outputs found

    Probing the accretion/ejection flows in AGN by characterizing Fe K emission/absorption line variability with residual maps

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    La dinamica e la geometria del materiale nelle vicinanze di un SMBH negli AGN sono ancora incerte, sia per quanto riguarda gli inflow sia per gli outflow, che possono essere responsabili del feedback da AGN sulla galassia ospite. L'analisi spettrale temporalmente risolta è fondamentale per studiare questi fenomeni e la banda energetica 4-10 keV è quella più adatta, in quanto vi si trova la riga di fluorescenza del ferro a 6.4 keV e, possibilmente, righe risonanti in assorbimento del ferro blueshiftate, indicative di venti da disco ultra-veloci. L'analisi adottata in questo lavoro di tesi si basa sulla tecnica dell'Excess Map, introdotta da Iwasawa et al. (2004). Lunghe esposizioni sono sezionate in intervalli temporali e ogni spettro risultante viene fittato con un semplice modello di continuo. I residui positivi sono quindi utilizzati per costruire un'immagine nel piano tempo vs. energia al fine di massimizzare la rivelazione di possibili strutture spettrali e derivarne l'evoluzione temporale. Laddove nelle Excess Map solo i residui positivi venivano considerati, tramite la nostra tecnica, denominata Residual Map, anche i residui negativi, legati a possibili strutture in assorbimento, vengono individuati e analizzati. Nel lavoro si è selezionato un campione di galassie di Seyfert 1 osservate con il satellite XMM-Newton, che garantisce la massima sensibilità nell'intervallo spettrale di interesse. Dal catalogo 3XMM-DR7 si sono scelte le sorgenti più brillanti nelle bande di interesse, NGC3783 e Mrk 509, e IRAS13224-3809, ossia quella con l'osservazione più lunga al momento disponibile, ma ad un livello di flusso inferiore. Nel lavoro ci si è focalizzati su un'osservazione particolarmente interessante tra quelle relative a NGC3783; in questa la riga del Ferro K_alpha mostra quattro picchi intervallati da circa 5-10 ks, corrispondenti ai tempi orbitali di un hot spot co-ruotante con il disco di accrescimento a distanze di circa 9-30 Rg

    Probing the innermost regions of AGN via time-resolved spectral analysis

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    The dynamics and geometry of the material inflowing and outflowing close to the supermassive black hole in active galactic nuclei are still uncertain. X-rays are the most suitable way to study the AGN innermost regions because of the Fe Kα emission line, a proxy of accretion, and Fe absorption lines produced by outflows. Winds are typically classified as Warm Absorbers (slow and mildly ionized) and Ultra Fast Outflows (fast and highly ionized). Transient Obscurers -optically thick winds that produce strong spectral hardening in X-rays, lasting from days to months- have been observed recently. Emission and absorption features vary on time-scales from hours to years, probing phenomena at different distances from the SMBH. In this work, we use time-resolved spectral analysis to investigate the accretion and ejection flows, to characterize them individually and search for correlations. We analyzed XMM-Newtomn data of a set of the brightest Seyfert 1 galaxies that went through an obscuration event: NGC 3783, NGC 3227, NGC 5548, and NGC 985. Our aim is to search for emission/absorption lines in short-duration spectra (∼ 10ks), to explore regions as close as the SMBH as the statistics allows for, and possibly catch transient phenomena. First we run a blind search to detect emission/absorption features, then we analyze their evolution with Residual Maps: we visualize simultaneously positive and negative residuals from the continuum in the time-energy plane, looking for patterns and relative time-scales. In NGC 3783 we were able to ascribe variations of the Fe Kα emission line to absorptions at the same energy due to clumps in the obscurer, whose presence is detected at >3σ, and to determine the size of the clumps. In NGC 3227 we detected a wind at ∼ 0.2c at ∼ 2σ, briefly appearing during an obscuration event

    Probing accretion/ejection flows in AGN by characterizing Fe K emission/absorption lines variability with residual maps

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    The dynamics and geometry of the material close to the SMBH in AGN are still largely uncertain, both as regards the inflows via accretion disk and the outflows.The latter phenomena may have a fundamental role in the AGN feedback on the host galaxy, so it is important to understand their properties and extent. A simultaneous investigation of inflows and outflows may highlight some kind of correlation, that shall help to unravel the driving mechanisms of massive winds from the disk, still an open issue. Time-resolved spectral analysis is a key tool to investigate these phenomena.The 4.0-10.0 keV energy band is the most suitable for these aims, because it includes the Fe Kα fluorescence emission line at 6.4 keV, a fundamental proxy of the motions around the SMBH, and possibly Fe resonant absorption lines, features that indicate the presence of massive, relativistic (<v>∼0.1c) disk winds (Ultra Fast Outflows, Tombesi et al. 2010), observed in about 50% of local AGN for which good quality data exist. We use a technique, Residual maps, that couples time and spectral analysis to the two X-ray brightest Seyfert 1 observed to date: NGC 3783 and Mrk 509. It allows to identify spectral features and trace their evolution in time. Residual maps can be used to detect potentially interesting time intervals, on which a deep spectral analysis can be (and will be) carried out to characterize the physical phenomena in act

    Anxiety, concerns and COVID-19: Cross-country perspectives from families and individuals with neurodevelopmental conditions

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    BACKGROUND: The COVID-19 pandemic had a major impact on the mental health and well-being of children with neurodevelopmental conditions (NDCs) and of their families worldwide. However, there is insufficient evidence to understand how different factors (e.g., individual, family, country, children) have impacted on anxiety levels of families and their children with NDCs developed over time. METHODS: We used data from a global survey assessing the experience of 8043 families and their children with NDCs (mean of age (m) = 13.18 years, 37% female) and their typically developing siblings (m = 12.9 years, 45% female) in combination with data from the European Centre for Disease Prevention and Control, the University of Oxford, and the Central Intelligence Agency (CIA) World Factbook, to create a multilevel data set. Using stepwise multilevel modelling, we generated child-, family- and country-related factors that may have contributed to the anxiety levels of children with NDCs, their siblings if they had any, and their parents. All data were reported by parents. RESULTS: Our results suggest that parental anxiety was best explained by family-related factors such as concerns about COVID-19 and illness. Children’s anxiety was best explained by child-related factors such as children’s concerns about loss of routine, family conflict, and safety in general, as well as concerns about COVID-19. In addition, anxiety levels were linked to the presence of pre-existing anxiety conditions for both children with NDCs and their parents. CONCLUSIONS: The present study shows that across the globe there was a raise in anxiety levels for both parents and their children with NDCs because of COVID-19 and that country-level factors had little or no impact on explaining differences in this increase, once family and child factors were considered. Our findings also highlight that certain groups of children with NDCs were at higher risk for anxiety than others and had specific concerns. Together, these results show that anxiety of families and their children with NDCs during the COVID-19 pandemic were predicted by very specific concerns and worries which inform the development of future toolkits and policy. Future studies should investigate how country factors can play a protective role during future crises

    Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

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    Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10&nbsp;years; 78.2% included were male with a median age of 37&nbsp;years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020

    Intimate Partner Violence Screening in the Prenatal Period: Variation by State, Insurance, and Patient Characteristics

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    Objective To measure the proportion of women screened for IPV during prenatal care; to assess the predictors of prenatal IPV screening. Methods We use the CDC’s 2012 Pregnancy Risk Assessment Monitoring System, representative of births in 24 states and New York City (N = 28,581). We calculated descriptive and logistic regressions, weighted to deal with state-clustered observations. Results 49.2% of women in our sample reported being screened for IPV while pregnant. There were higher screening rates among women of color, and those who had not completed high school, never been married, received WIC benefits, initiated prenatal care in the first trimester, and were publicly insured. State screening rates varied (29.9–62.9%). Among states, mandated perinatal depression screening or training was positively associated with IPV screening. 3.6% of women in our sample reported prenatal IPV but were not screened during pregnancy. Conclusions for Practice Current efforts have not led to universal screening. We need to better understand when and why providers do not screen pregnant patients for IPV

    Effects of Lippia citriodora Leaf Extract on Lipid and Oxidative Blood Profile of Volunteers with Hypercholesterolemia: A Preliminary Study

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    Lippia citriodora is a plant traditionally used for its anti-inflammatory, antioxidant and antispasmodic effects, as well as for additional biological activities proven in cell culture, animal studies and a small number of human clinical trials. The plant has also shown a marked improvement in blood lipid profile in some animal species. In the present preliminary study, we investigated the effect of a leaf extract on lipid and oxidative blood profile of hypercholesterolemic volunteers. Twelve adults received Lippia citriodora extract caps, containing 23% phenylpropanoids, (100 mg, once a day) for 16 weeks. Selected blood lipids and plasma oxidative markers were measured at baseline and after 4, 8 and 16 weeks of treatment. Compared with baseline, total cholesterol levels significantly decreased and high-density lipoprotein cholesterol increased, while low-density lipoprotein cholesterol and triglycerides showed only a downward trend. Oxidative status was improved due to a decrease in the concentration of total oxidant status, reactive oxygen metabolites and malondialdehyde, and a significant increase in ferric reducing ability of plasma, vitamin A and vitamin E. These preliminary results suggest that dietary supplementation with Lippia citriodora extract can improve the lipid profile, enhance blood antioxidant power, and could be a valuable natural compound for the management of human hypercholesterolemia

    Application of Sebum Lipidomics to Biomarkers Discovery in Neurodegenerative Diseases

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    Lipidomics is strategic in the discovery of biomarkers of neurodegenerative diseases (NDDs). The skin surface lipidome bears the potential to provide biomarker candidates in the detection of pathological processes occurring in distal organs. We investigated the sebum composition to search diagnostic and, possibly, prognostic, biomarkers of Alzheimer’s disease (AD) and Parkinson’s disease (PD). The observational study included 64 subjects: 20 characterized as “probable AD with documented decline”, 20 as “clinically established PD”, and 24 healthy subjects (HS) of comparable age. The analysis of sebum by GCMS and TLC retrieved the amounts (µg) of 41 free fatty acids (FFAs), 7 fatty alcohols (FOHs), vitamin E, cholesterol, squalene, and total triglycerides (TGs) and wax esters (WEs). Distributions of sebum lipids in NDDs and healthy conditions were investigated with multivariate ANOVA-simultaneous component analysis (ASCA). The deranged sebum composition associated with the PD group showed incretion of most composing lipids compared to HS, whereas only two lipid species (vitamin E and FOH14:0) were discriminant of AD samples and presented lower levels than HS sebum. Thus, sebum lipid biosynthetic pathways are differently affected in PD and AD. The characteristic sebum bio-signatures detected support the value of sebum lipidomics in the biomarkers search in NDDs
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