628 research outputs found
Integrative bioinformatics and omics data source interoperability in the next-generation sequencing era-Editorial
With the advent of high-throughput and next-generation sequencing (NGS) technologies [1], huge amounts of \u2018omics\u2019 data (i.e. data from genomics, proteomics, pharmacogenomics, metagenomics, etc.) are continuously produced. Combining and integrating diverse omics data types is important in order to investigate the molecular machinery of complex diseases, with the hope for better disease prevention and treatment [2]. Experimental data repositories of omics data are publicly available, with the main aim of fostering the cooperation among research groups and laboratories all over the world. However, despite their openness, the effective integrated use of available public sources is hampered by the heterogeneity, complexity and large size of data stored therein
Causality estimates among brain cortical areas by Partial Directed Coherence: simulations and application to real data
The problem of the definition and evaluation of brain connectivity has become a central one in neuroscience during the latest years, as a way to understand the organization and interaction of cortical areas during the execution of cognitive or motor tasks. Among various methods established during the years, the Partial Directed Coherence (PDC) is a frequency-domain approach to this problem, based on a multivariate autoregressive modeling of time series and on the concept of Granger causality. In this paper we propose the use of the PDC method on cortical signals estimated from high resolution EEG recordings, a non invasive method which exhibits a higher spatial resolution than conventional cerebral electromagnetic measures. The principle contributions of this work are the results of a simulation study, testing the performances of PDC, and a statistical analysis (via the ANOVA, analysis of variance) of the influence of different levels of Signal to Noise Ratio and temporal length, as they have been systematically imposed on simulated signals. An application to high resolution EEG recordings during a foot movement is also presented
Studying the WHIM with Gamma Ray Bursts
We assess the possibility to detect and characterize the physical state of
the missing baryons at low redshift by analyzing the X-ray absorption spectra
of the Gamma Ray Burst [GRB] afterglows, measured by a micro calorimeters-based
detector with 3 eV resolution and 1000 cm2 effective area and capable of fast
re-pointing, similar to that on board of the recently proposed X-ray satellites
EDGE and XENIA. For this purpose we have analyzed mock absorption spectra
extracted from different hydrodynamical simulations used to model the
properties of the Warm Hot Intergalactic Medium [WHIM]. These models predict
the correct abundance of OVI absorption lines observed in UV and satisfy
current X-ray constraints. According to these models space missions like EDGE
and XENIA should be able to detect about 60 WHIM absorbers per year through the
OVII line. About 45 % of these have at least two more detectable lines in
addition to OVII that can be used to determine the density and the temperature
of the gas. Systematic errors in the estimates of the gas density and
temperature can be corrected for in a robust, largely model-independent
fashion. The analysis of the GRB absorption spectra collected in three years
would also allow to measure the cosmic mass density of the WHIM with about 15 %
accuracy, although this estimate depends on the WHIM model. Our results suggest
that GRBs represent a valid, if not preferable, alternative to Active Galactic
Nuclei to study the WHIM in absorption. The analysis of the absorption spectra
nicely complements the study of the WHIM in emission that the spectrometer
proposed for EDGE and XENIA would be able to carry out thanks to its high
sensitivity and large field of view.Comment: 16 pages, 16 figures, accepted for publication by Ap
Role of perfusion CT in the evaluation of metastatic nodal tumor response after radiochemotherapy in head and neck cancer: preliminary findings
OBJECTIVE: To assess changes of CT perfusion parameters (ΔPCTp) of cervical lymph node metastases from head and neck
cancer (HNC) before and after radiochemotherapy (RT-CT) and their association with nodal tumor persistence.
PATIENTS AND METHODS: Eligibility criteria included HNC (Stage III-IV) candidates for RT-CT. Patients underwent perfusion CT (PCT) at baseline 3 weeks and 3 months after RT-CT. Blood volume (BV), blood flow (BF), mean transit time (MTT) and permeability surface (PS) were calculated. PET/CT examination was also performed at baseline and 3 months after treatment
for metabolic assessment.
RESULTS: Between July 2012 and May 2016, 27 patients were evaluated. Overall, only 3 patients (11%) experienced tumor persistence in the largest metastatic lymph node. A significant reduction of all PCTp values (p<0.0001), except MTT (from 6.3 to 5.7 s; p=0.089), was observed at 3 weeks post-RT-CT compared to baseline. All PCTp values including MTT were significantly lower at 3-month follow-up compared to baseline (p<0.05). Moreover, a statistical significant association was observed between nodal tumor persistence and high BF values (p=0.045) at 3 months after treatment that did not occur for the other parameters.
CONCLUSIONS: Our preliminary findings show that all PCTp except MTT are significantly reduced after RT-CT. High BF values at 3 months post-RTCT are predictive of nodal tumor persistence
Xmm-Newton Observations of the Diffuse X-ray Background
We analyzed two XMM-Newton observations in the direction of the high density,
high latitude, neutral hydrogen cloud MBM20 and of a nearby low density region
that we called the Eridanus hole. The cloud MBM20 is at a distance evaluated
between 100 and 200 pc from the Sun and its density is sufficiently high to
shield about 75% of the foreground emission in the 3/4 keV energy band.The
combination of the two observations makes possible an evaluation of the OVII
and OVIII emission both for the foreground component due to the Local
Bubble,and the background one, due primary to the galactic halo.The two
observations are in good agreement with each other and with ROSAT observations
of the same part of the sky and the OVII and OVIII fluxes are OVII=3.89+/-0.56
photons cm^-2 s^-1 sr^-1, OVIII=0.68+/-0.24 photons cm^-2 s^-1 sr^-1 for MBM20
and OVII=7.26+/-0.34 photons cm^-2 s^-1 sr^-1,OVIII=1.63+/-0.17 photons cm^-2
s^-1 sr^-1 for the Eridanus hole. The spectra are in agreement with a simple
three component model, one unabsorbed and one absorbed plasma component, and a
power law, without evidence for any strong contamination from ion exchange in
the solar system. Assuming that the two plasma components are in thermal
equilibrium we obtain a temperature of 0.096 keV for the foreground component
and 0.197 keV for the background one. Assuming the foreground component is due
solely to Local Bubble emission we obtain a lower and upper limit for the
plasma density of 0.0079 cm^-3 and 0.0095 cm^-3 and limits of 16,200 cm^-3 K
and 19,500 cm^-3 K for the plasma pressure, in good agreement with theoretical
predictions. Similarly, assuming that the absorbed plasma component is due to
Galactic halo emission, we obtain a plasma density ranging from 0.0009 cm^-3 to
0.0016 cm^-3, and a pressure ranging from 3.0*10^3 to 6.7*10^3 cm^-3 K.Comment: 31 pages, 5 figures, Accepted for publication in Ap
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