290 research outputs found
Time Aware Knowledge Extraction for Microblog Summarization on Twitter
Microblogging services like Twitter and Facebook collect millions of user
generated content every moment about trending news, occurring events, and so
on. Nevertheless, it is really a nightmare to find information of interest
through the huge amount of available posts that are often noise and redundant.
In general, social media analytics services have caught increasing attention
from both side research and industry. Specifically, the dynamic context of
microblogging requires to manage not only meaning of information but also the
evolution of knowledge over the timeline. This work defines Time Aware
Knowledge Extraction (briefly TAKE) methodology that relies on temporal
extension of Fuzzy Formal Concept Analysis. In particular, a microblog
summarization algorithm has been defined filtering the concepts organized by
TAKE in a time-dependent hierarchy. The algorithm addresses topic-based
summarization on Twitter. Besides considering the timing of the concepts,
another distinguish feature of the proposed microblog summarization framework
is the possibility to have more or less detailed summary, according to the
user's needs, with good levels of quality and completeness as highlighted in
the experimental results.Comment: 33 pages, 10 figure
Strong modulation of optical properties in black phosphorus through strain-engineered rippling
Controlling the bandgap through local-strain engineering is an exciting
avenue for tailoring optoelectronic materials. Two-dimensional crystals are
particularly suited for this purpose because they can withstand unprecedented
non-homogeneous deformations before rupture: one can literally bend them and
fold them up almost like a piece of paper. Here, we study multi-layer black
phosphorus sheets subjected to periodic stress to modulate their optoelectronic
properties. We find a remarkable shift of the optical absorption band-edge of
up to ~0.7 eV between the regions under tensile and compressive stress, greatly
exceeding the strain tunability reported for transition metal dichalcogenides.
This observation is supported by theoretical models which also predict that
this periodic stress modulation can yield to quantum confinement of carriers at
low temperatures. The possibility of generating large strain-induced variations
in the local density of charge carriers opens the door for a variety of
applications including photovoltaics, quantum optics and two-dimensional
optoelectronic devices.Comment: 16 pages main text + 13 pages S
Oral platelet gel supernatant plus supportive medical treatment versus supportive medical treatment in the management of radiation-induced oral mucositis: a matched explorative active control trial by propensity analysis
OBJECTIVES:: In this active control trial, the rate of radio-induced WHO grade 3/4 oral mucositis and the change in quality of life, assessed by OMWQ-HN, were measured in subjects with head and neck cancer treated by platelet gel supernatant (PGS) and supportive medical treatment versus subjects treated by supportive medical treatment alone. MATERIALS AND METHODS:: Eighty patients with nonmetastatic head and neck cancer underwent curative or adjuvant radiotherapy. All patients underwent supportive medical treatment and/or PGS at the beginning and during radiotherapy. Sixteen patients received PGS in association with supportive medical treatment. To obtain 2 groups virtually randomized for important clinical characteristics subjects were matched, by propensity analysis, with a group of subjects (64 patients) treated with supportive medical treatment alone. RESULTS:: Subjects treated with standard supportive treatment experienced significant higher WHO grade 3/4 toxicity (55%; 35/64) than subjects treated by PGS (13%; 3/16). The reduced toxicity found in PGS group paralleled with the evidence that they developed later symptoms with respect to controls. The Cox proportional hazard model indicated that patients treated with standard supportive medical treatment experienced 2.7-fold increase (hazard ratio=2.7; 95% confidence interval, 1.3-5.7) in the occurrence of WHO grade 3/4 toxicity. PGS group significantly experienced higher quality of life than control groups as measured by OMWQ-HN. A significant decrease in the opioid analgesics usage was found in the PGS group. CONCLUSIONS:: These preliminary data should be interpreted with caution and could serve as a framework around which to design future trials
A New Orbiting Deployable System for Small Satellite Observations for Ecology and Earth Observation
In this paper, we present several study cases focused on marine, oceanographic, and
atmospheric environments, which would greatly benefit from the use of a deployable system for
small satellite observations. As opposed to the large standard ones, small satellites have become an
effective and affordable alternative access to space, owing to their lower costs, innovative design
and technology, and higher revisiting times, when launched in a constellation configuration. One
of the biggest challenges is created by the small satellite instrumentation working in the visible
(VIS), infrared (IR), and microwave (MW) spectral ranges, for which the resolution of the acquired
data depends on the physical dimension of the telescope and the antenna collecting the signal. In
this respect, a deployable payload, fitting the limited size and mass imposed by the small satellite
architecture, once unfolded in space, can reach performances similar to those of larger satellites.
In this study, we show how ecology and Earth Observations can benefit from data acquired by
small satellites, and how they can be further improved thanks to deployable payloads. We focus on
DORA—Deployable Optics for Remote sensing Applications—in the VIS to TIR spectral range, and
on a planned application in the MW spectral range, and we carry out a radiometric analysis to verify
its performances for Earth Observation studies
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than detected with the Pierre Auger
Observatory between 1 January 2004 and 31 December 2013. The measured spectrum
confirms a flux suppression at the highest energies. Above
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
eV.Comment: Replaced with published version. Added journal reference and DO
Epigenetic Silencing of Peroxisome Proliferator-Activated Receptor γ Is a Biomarker for Colorectal Cancer Progression and Adverse Patients' Outcome
The relationship between peroxisome proliferator-activated receptor γ (PPARG) expression and epigenetic changes occurring in colorectal-cancer pathogenesis is largely unknown. We investigated whether PPARG is epigenetically regulated in colorectal cancer (CRC) progression. PPARG expression was assessed in CRC tissues and paired normal mucosa by western blot and immunohistochemistry and related to patients' clinicopathological parameters and survival. PPARG promoter methylation was analyzed by methylation-specific-PCR and bisulphite sequencing. PPARG expression and promoter methylation were similarly examined also in CRC derived cell lines. Chromatin immunoprecipitation in basal conditions and after epigenetic treatment was performed along with knocking-down experiments of putative regulatory factors. Gene expression was monitored by immunoblotting and functional assays of cell proliferation and invasiveness. Methylation on a specific region of the promoter is strongly correlated with PPARG lack of expression in 30% of primary CRCs and with patients' poor prognosis. Remarkably, the same methylation pattern is found in PPARG-negative CRC cell lines. Epigenetic treatment with 5′-aza-2′-deoxycytidine can revert this condition and, in combination with trichostatin A, dramatically re-activates gene transcription and receptor activity. Transcriptional silencing is due to the recruitment of MeCP2, HDAC1 and EZH2 that impart repressive chromatin signatures determining an increased cell proliferative and invasive potential, features that can experimentally be reverted. Our findings provide a novel mechanistic insight into epigenetic silencing of PPARG in CRC that may be relevant as a prognostic marker of tumor progression
Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory
The Auger Engineering Radio Array (AERA) is part of the Pierre Auger
Observatory and is used to detect the radio emission of cosmic-ray air showers.
These observations are compared to the data of the surface detector stations of
the Observatory, which provide well-calibrated information on the cosmic-ray
energies and arrival directions. The response of the radio stations in the 30
to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of
the incoming electric field. For the latter, the energy deposit per area is
determined from the radio pulses at each observer position and is interpolated
using a two-dimensional function that takes into account signal asymmetries due
to interference between the geomagnetic and charge-excess emission components.
The spatial integral over the signal distribution gives a direct measurement of
the energy transferred from the primary cosmic ray into radio emission in the
AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air
shower arriving perpendicularly to the geomagnetic field. This radiation energy
-- corrected for geometrical effects -- is used as a cosmic-ray energy
estimator. Performing an absolute energy calibration against the
surface-detector information, we observe that this radio-energy estimator
scales quadratically with the cosmic-ray energy as expected for coherent
emission. We find an energy resolution of the radio reconstruction of 22% for
the data set and 17% for a high-quality subset containing only events with at
least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO
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