486 research outputs found
Iron Abundance Diagnostics in High-Redshift QSOs
The abundance of alpha-process elements such as magnesium and carbon relative
to iron measured from the broad emission lines of QSOs can serve as a
diagnostic of the star formation and chemical enrichment histories of their
host galaxies.
We investigate the relationship between Fe/Mg and Fe/C abundance ratios and
the resulting Fe II / Mg II 2800A and Fe II / 1900A-blend flux ratios, both of
which have been measured in QSOs out to redshifts of approximately six. Using a
galactic chemical evolution model based on a starburst in a giant elliptical
galaxy, we find that these flux ratios are good tracers of the chemical
enrichment of the nuclei. However, the values of these ratios measured in
objects at redshifts of approximately six suggest that iron enrichment has
occurred more rapidly in these objects than predicted by the assumed elliptical
starburst model, under currently favored cosmologies.Comment: 2 pages, to appear in proceedings of IAU Symposium No. 222, The
Interplay Among Black Holes, Stars and ISM in Galacti Nucle
Chemical Abundances in AGN Environment: X-Ray/UV Campaign on the MRK 279 Outflow
We present the first reliable determination of chemical abundances in an AGN
outflow. The abundances are extracted from the deep and simultaneous FUSE and
HST/STIS observations of Mrk 279. This data set is exceptional for its high
signal-to-noise, unblended doublet troughs and little Galactic absorption
contamination. These attributes allow us to solve for the velocity-dependent
covering fraction, and therefore obtain reliable column densities for many
ionic species. For the first time we have enough such column densities to
simultaneously determine the ionization equilibrium and abundances in the flow.
Our analysis uses the full spectral information embedded in these
high-resolution data. Slicing a given trough into many independent outflow
elements yields the extra constraints needed for a physically meaningful
abundances determination. We find that relative to solar the abundances in the
Mrk 279 outflow are (linear scaling): carbon 2.2+/-0.7, nitrogen 3.5+/-1.1 and
oxygen 1.6+/-0.8. Our UV-based photoionization and abundances results are in
good agreement with the independent analysis of the simultaneous Mrk 279 X-ray
spectra. This is the best agreement between the UV and X-ray analyses of the
same outflow to date.Comment: 28 pages, 7 figures, accepted on 29 Nov 2006 for publication in the
ApJ (submission date: 27 Jul 2006
Signature of a polyamorphic transition in the THz spectrum of vitreous GeO2
The THz spectrum of density fluctuations, , of vitreous GeO
at ambient temperature was measured by inelastic x-ray scattering from ambient
pressure up to pressures well beyond that of the known -quartz to
rutile polyamorphic (PA) transition. We observe significant differences in the
spectral shape measured below and above the PA transition, in particular, in
the 30-80 meV range. Guided by first-principle lattice dynamics calculations,
we interpret the changes in the phonon dispersion as the evolution from a
quartz-like to a rutile-like coordination. Notably, such a crossover is
accompanied by a cusp-like behavior in the pressure dependence of the elastic
response of the system. Overall, the presented results highlight the complex
fingerprint of PA phenomena on the high-frequency phonon dispersion.Comment: 18 pages, 5 figure
Telepractice in the Communication Treatment of Individuals with Post-stroke Aphasia: Systematic Review
Telepractice, a branch of telehealth, which is the delivery of services to distant sites employing telecommunication, has been developing rapidly nowadays. Owing to the nature of the condition and treatment foci in aphasia, telepractice has been identified as a potential mode for intervention to persons with aphasia (PWA) in the field of speech-language pathology. Based on the American Speech-Language Hearing Association (2005), telepractice is considered a means to extend services to a wider context overcoming the barriers of transportation, costs, and limited availability of services. Thus, exploration of treatment accessibility to underserved populations in middle/low-income countries or rural areas via telepractice is warranted. The primary objectives of this study are to systematically review literature on telepractice of speech-language pathology services for PWA, with a focus to synthesize and analyze data that will be useful to low-income countries to consider telepractice as an alternate option and also to contribute to broaden the evidence base of aphasia practices via telepractice and include the newest available evidence.
A systematic review was conducted in this study following the guidelines of Cochrane Handbook (Higgins et al., 2020). The study utilized a systematic search based on PRISMA guidelines and included 11 articles following a thorough screen for eligibility. A pre-designed coding manual was utilized in order to extract relevant data. All the included studies evaluated the feasibility of telepractice in intervention and to investigate the effectiveness of treatment programs conducted via teletherapy. A majority of the participants (72%) included in the review are PWA secondary to strokes. The treatment areas studies targeted are word retrieval, language skills, communication skills and language and communication skills, with communication skills being the area covered in highest number of studies. The review found that telepractice in the targeted treatment programs is feasible and effective. However, the included articles lack strong methodological designs limiting the certainty of the evidence. Participant-perceived data indicated some advantages of telepractice, such as overcoming transport/cost barriers, receival of higher intensity of treatment, and facilitations for non-verbal strategies to improve language and communication skills. In addition, the results revealed that all but one of the included studies was completed in a high-income country. Most of the findings also lack adequate details on therapy receival and delivery setting dynamics from a standpoint of replicating the studies or in order to generalize the findings.
In conclusion, the current review shows limited evidence guidelines for the use of telepractice in rural and middle/low-income countries. There is a need to explore simple affordable technology options in telepractice and evaluate their effectiveness in low/middle-income contexts. Empirical data on efficacy of telepractice for PWA drawn from strong methodological designs should also be considered to encourage evidence-based clinical practice using telepractice in those contexts
InSight2: An Interactive Web Based Platform for Modeling and Analysis of Large Scale Argus Network Flow Data
Monitoring systems are paramount to the proactive detection and mitigation of problems in computer networks related to performance and security. Degraded performance and compromised end-nodes can cost computer networks downtime, data loss and reputation. InSight2 is a platform that models, analyzes and visualizes large scale Argus network flow data using up-to-date geographical data, organizational information, and emerging threats. It is engineered to meet the needs of network administrators with flexibility and modularity in mind. Scalability is ensured by devising multi-core processing by implementing robust software architecture. Extendibility is achieved by enabling the end user to enrich flow records using additional user provided databases. Deployment is streamlined by providing an automated installation script. State-of-the-art visualizations are devised and presented in a secure, user friendly web interface giving greater insight about the network to the end user
Heart rate variability and target organ damage in hypertensive patients
Background:
We evaluated the association between linear standard Heart Rate Variability (HRV) measures and vascular, renal and cardiac target organ damage (TOD).
Methods:
A retrospective analysis was performed including 200 patients registered in the Regione Campania network (aged 62.4 ± 12, male 64%). HRV analysis was performed by 24-h holter ECG. Renal damage was assessed by estimated glomerular filtration rate (eGFR), vascular damage by carotid intima-media thickness (IMT), and cardiac damage by left ventricular mass index.
Results:
Significantly lower values of the ratio of low to high frequency power (LF/HF) were found in the patients with moderate or severe eGFR (p-value < 0.001). Similarly, depressed values of indexes of the overall autonomic modulation on heart were found in patients with plaque compared to those with a normal IMT (p-value <0.05). These associations remained significant after adjustment for other factors known to contribute to the development of target organ damage, such as age. Moreover, depressed LF/HF was found also in patients with left ventricular hypertrophy but this association was not significant after adjustment for other factors.
Conclusions:
Depressed HRV appeared to be associated with vascular and renal TOD, suggesting the involvement of autonomic imbalance in the TOD. However, as the mechanisms by which abnormal autonomic balance may lead to TOD, and, particularly, to renal organ damage are not clearly known, further prospective studies with longitudinal design are needed to determine the association between HRV and the development of TOD
Federated Agentless Detection of Endpoints Using Behavioral and Characteristic Modeling
During the past two decades computer networks and security have evolved that, even though we use the same TCP/IP stack, network traffic behaviors and security needs have significantly changed. To secure modern computer networks, complete and accurate data must be gathered in a structured manner pertaining to the network and endpoint behavior. Security operations teams struggle to keep up with the ever-increasing number of devices and network attacks daily. Often the security aspect of networks gets managed reactively instead of providing proactive protection. Data collected at the backbone are becoming inadequate during security incidents. Incident response teams require data that is reliably attributed to each individual endpoint over time. With the current state of dissociated data collected from networks using different tools it is challenging to correlate the necessary data to find origin and propagation of attacks within the network. Critical indicators of compromise may go undetected due to the drawbacks of current data collection systems leaving endpoints vulnerable to attacks. Proliferation of distributed organizations demand distributed federated security solutions. Without robust data collection systems that are capable of transcending architectural and computational challenges, it is becoming increasingly difficult to provide endpoint protection at scale. This research focuses on reliable agentless endpoint detection and traffic attribution in federated networks using behavioral and characteristic modeling for incident response
Parental Substance Abuse As an Early Traumatic Event. Preliminary Findings on Neuropsychological and Personality Functioning in Young Drug Addicts Exposed to Drugs Early.
open5noParental substance use is a major risk factor for child development, heightening the risk of drug problems in adolescence and young adulthood, and exposing offspring to several types of traumatic events. First, prenatal drug exposure can be considered a form of trauma itself, with subtle but long-lasting sequelae at the neuro-behavioral level. Second, parents’ addiction often entails a childrearing environment characterized by poor parenting skills, disadvantaged contexts and adverse childhood experiences (ACEs), leading to dysfunctional outcomes. Young adults born from/raised by parents with drug problems and diagnosed with a Substance Used Disorder (SUD) themselves might display a particularly severe condition in terms of cognitive deficits and impaired personality function. This preliminary study aims to investigate the role of early exposure to drugs as a traumatic event, capable of affecting the psychological status of young drug addicts. In particular, it intends to examine the neuropsychological functioning and personality profile of young adults with severe SUDs who were exposed to drugs early in their family context. The research involved three groups, each consisting of 15 young adults (aged 18–24): a group of inpatients diagnosed with SUDs and exposed to drugs early, a comparison group of non-exposed inpatients and a group of non-exposed youth without SUDs. A neuropsychological battery (Esame Neuropsicologico Breve-2), an assessment procedure for personality disorders (Shedler-Westen Assessment Procedure-200) and the Symptom CheckList-90-Revised were administered. According to present preliminary results, young drug addicts exposed to drugs during their developmental age were characterized by elevated rates of neuropsychological impairments, especially at the expense of attentive and executive functions (EF); personality disorders were also common but did not differentiate them from non-exposed youth with SUDs. Alternative multi-focused prevention and intervention programs are needed for children of drug-misusing parents, addressing EF and adopting a trauma-focused approach.openParolin, Micol; Simonelli, Alessandra; Mapelli, Daniela; Sacco, M.; Cristofalo, P.Parolin, Micol; Simonelli, Alessandra; Mapelli, Daniela; Sacco, M.; Cristofalo, P
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