1,127 research outputs found
Alarm guard systems for the prevention of damage produced by ungulates in a chestnut grove of Middle Italy
ArticleWildlife populations, in particular
ungulates and carnivores, have had a significant
increase in most Italian regions over the last decades and for this reason ecosystems and
agricultural and forest productions are threatened by damage produced by wildlife. In order to
evaluate effective met
hodologies and technologies to mitigate the impact of this phenomenon,
innovative protection systems, such as electronic acoustic alarm guard sensors, were tested. These
devices are able to randomly produce a significant number of sounds and light projecti
ons. At the
same time, camera traps were used, as a support instrument to show the presence or absence of
wild fauna. Video analysis has provided information on the effectiveness of security systems, on
the most suitable methods of installation and managem
ent of devices and their ecological impact.
Experimental trials were carried out in a chestnut grove located in an Apennine area of the Middle
Italy during the harvesting period (autumn). The results obtained have shown that these
technologies seem to be
particularly suitable for crops that concentrate production in a short time
(e.g. vine and chestnut) and in areas not excessively large. Widespread use of devices could
mitigate the conflict between public bodies involved in the management of wildlife and
farmers
Immunotherapy in endometrial cancer: new scenarios on the horizon
This extensive review summarizes clinical evidence on immunotherapy and targeted therapy currently available for endometrial cancer (EC) and reports the results of the clinical trials and ongoing studies. The research was carried out collecting preclinical and clinical findings using keywords such as immune environment, tumor infiltrating lymphocytes, programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1) expression, immune checkpoint inhibitors, anti-PD-1/PD-L1 antibodies and others’ on PubMed. Finally, we looked for the ongoing immunotherapy trials on ClinicalTrials.gov. EC is the fourth most common malignancy in women in developed countries. Despite medical and surgical treatments, survival has not improved in the last decade and death rates have increased for uterine cancer in women. Therefore, identification of clinically significant prognostic risk factors and formulation of new rational therapeutic regimens have great significance for enhancing the survival rate and improving the outcome in patients with advanced or metastatic disease. The identification of genetic alterations, including somatic mutations and microsatellite instability, and the definition of intracellular signaling pathways alterations that have a major role in in tumorigenesis is leading to the development of new therapeutic options for immunotherapy and targeted therapy
Identification and Characterization of BRCA1 and BRCA2 Founder Mutations
A large number of cancer predisposing BRCA1/BRCA2 mutations have been reported, with a wide variety among populations. In some restricted groups, specific germline mutations in these tumor suppressor genes have been found with high predominance, due to a founder effect. We focused our review on the Italian founder mutations. The first Italian BRCA1 founder mutation, 5083del19, was found in Calabria: the presence of common allele in all carriers of this mutation (also in families with Calabrian origin living in other parts of Italy) confirmed its founder effect. The same BRCA1 mutation was identified in the Sicilian population, but only the haplotype analysis can reveal the common ancestor of these groups. Another BRCA1 founder mutation, 4843delC, was found in Sicily. Four distinct BRCA1 mutations are attributable to families original from Tuscany: 3348delAG, 3285delA, 1499insA and 5183delTGT; the latter has been shown to be a founder mutation from North-Eastern Italy. The first BRCA2 mutation was identified in Sardinia, 8765delAG, a mutation already described as a founder mutation in Jewish-Yemenite families and also in French-Canadian population but with independent origins of carriers in these three populations. BRCA2 3951del3 and BRCA1 917delTT have been described as founder mutations in Middle Sardinia and in South and Middle Sardinia, respectively. Studies regarding prevalence and penetrance of founder mutations can allow to quantify the degree of homogeneity within a population and can surely help the geneticist and oncologist to simplify their choices in the genetic testing on high-risk families, on the basis of their ethnical origin
A low-frequency view of mixed-morphology supernova remnant VRO 42.05.01, and its neighbourhood
Context. Mixed-morphology supernova remnants (MM SNRs) are a mysterious class of objects that display thermal X-ray emission within their radio shell. They are an older class of SNRs, and as such are profoundly affected by the environment into which they evolve. VRO 42.05.01 is a MM SNR of puzzling morphology in the direction of the Galactic anticentre.
Aims. Low-frequency radio observations of supernova remnants are sensitive to synchrotron electrons accelerated in the shock front. We aim to compare the low-frequency emission to higher frequency observations to understand the environmental and shock acceleration conditions that have given rise to the observed properties of this source.
Methods. We present a LOFAR High Band Antenna map centred at 143 MHz of the region of the Galactic plane centred at l = 166°, b = 3.5° at 143 MHz, with a resolution of 148" and an rms noise of 4.4 mJy bm−1. Our map is sensitive to scales as large as 6°. We compared the LOw Frequency ARay (LOFAR) observations to archival higher frequency radio, infrared, and optical data to study the emission properties of the source in different spectral regimes. We did this both for the SNR and for OA 184, an H II region within our field of view.
Results. We find that the radio spectral index of VRO 42.05.01 increases at low radio frequencies; i.e. the LOFAR flux is higher than expected from the measured spectral index value at higher radio frequencies. This observed curvature in the low-frequency end of the radio spectrum occurs primarily in the brightest regions of the source, while the fainter regions present a roughly constant power-law behaviour between 143 MHz and 2695 MHz. We favour an explanation for this steepening whereby radiative shocks have high compression ratios and electrons of different energies probe different length scales across the shocks, therefore sampling regions of different compression ratios
The LOFAR view of intergalactic magnetic fields with giant radio galaxies
Context. Giant radio galaxies (GRGs) are physically large radio sources that extend well beyond their host galaxy environment. Their polarization properties are affected by the poorly constrained magnetic field that permeates the intergalactic medium on megaparsec scales. A low frequency (< 200 MHz) polarization study of this class of radio sources is now possible with LOFAR. Aims. Here we investigate the polarization properties and Faraday rotation measure (RM) of a catalog of GRGs detected in the LOFAR Two-meter Sky Survey. This is the first low frequency polarization study of a large sample of radio galaxies that were selected on their physical size. We explore the magneto-ionic properties of their under-dense environment and probe intergalactic magnetic fields using the Faraday rotation properties of their radio lobes. LOFAR is a key instrument for this kind of analysis because it can probe small amounts of Faraday dispersion (< 1 rad m-2), which are associated with weak magnetic fields and low thermal gas densities. Methods. We used RM synthesis in the 120-168 MHz band to search for polarized emission and to derive the RM and fractional polarization of each detected source component. We study the depolarization between 1.4 GHz and 144 MHz using images from the NRAO VLA Sky Survey. We investigate the correlation of the detection rate, the RM difference between the lobes, and the depolarization with different parameters as follows: the angular and linear size of the sources and the projected distance from the closest foreground galaxy cluster. In our sample, we also included 3C 236, which is one of the largest radio galaxies known. Results. From a sample of 240 GRGs, we detected 37 sources in polarization, all of which have a total flux density above 56 mJy. We detected significant RM differences between the lobes, which would be inaccessible at gigahertz frequencies, with a median value of ∼1 rad m-2. The fractional polarization of the detected GRGs at 1.4 GHz and 144 MHz is consistent with a small amount of Faraday depolarization (a Faraday dispersion < 0.3 rad m-2). Our analysis shows that the lobes are expanding into a low-density (< 10-5 cm-3) local environment that is permeated by weak magnetic fields (< 0.1 μG) with fluctuations on scales of 3-25 kpc. The presence of foreground galaxy clusters appears to influence the polarization detection rate up to 2R500. In general, this work demonstrates the ability of LOFAR to quantify the rarefied environments in which these GRGs exist and highlights them as an excellent statistical sample to use as high precision probes of magnetic fields in the intergalactic medium and the Milky Way
Galactic interstellar filaments as probed by LOFAR and Planck
Recent Low Frequency Array (LOFAR) observations at 115-175 MHz of a field at
medium Galactic latitudes (centered at the bright quasar 3C196) have shown
striking filamentary structures in polarization that extend over more than 4
degrees across the sky. In addition, the Planck satellite has released full sky
maps of the dust emission in polarization at 353GHz. The LOFAR data resolve
Faraday structures along the line of sight, whereas the Planck dust
polarization maps probe the orientation of the sky projected magnetic field
component. Hence, no apparent correlation between the two is expected. Here we
report a surprising, yet clear, correlation between the filamentary structures,
detected with LOFAR, and the magnetic field orientation, probed by the Planck
satellite. This finding points to a common, yet unclear, physical origin of the
two measurements in this specific area in the sky. A number of follow-up multi-
frequency studies are proposed to shed light on this unexpected finding.Comment: 6 pages, 4 figures, accepted for publication in MNRAS Letter
LOFAR MSSS: Flattening low-frequency radio continuum spectra of nearby galaxies
Accepted for publication in Astronomy and AstrophysicsAims. The shape of low-frequency radio continuum spectra of normal galaxies is not well understood, the key question being the role of physical processes such as thermal absorption in shaping them. In this work we take advantage of the LOFAR Multifrequency Snapshot Sky Survey (MSSS) to investigate such spectra for a large sample of nearby star-forming galaxies. Methods. Using the measured 150 MHz flux densities from the LOFAR MSSS survey and literature flux densities at various frequencies we have obtained integrated radio spectra for 106 galaxies characterised by different morphology and star formation rate. The spectra are explained through the use of a three-dimensional model of galaxy radio emission, and radiation transfer dependent on the galaxy viewing angle and absorption processes. Results. Our galaxies' spectra are generally flatter at lower compared to higher frequencies: the median spectral index α low measured between ≈ 50 MHz and 1.5 GHz is -0.57 ± 0.01 while the high-frequency one α high, calculated between 1.3 GHz and 5 GHz, is -0.77 ± 0.03. As there is no tendency for the highly inclined galaxies to have more flattened low-frequency spectra, we argue that the observed flattening is not due to thermal absorption, contradicting the suggestion of Israel & Mahoney (1990, ApJ, 352, 30). According to our modelled radio maps for M 51-like galaxies, the free-free absorption effects can be seen only below 30 MHz and in the global spectra just below 20 MHz, while in the spectra of starburst galaxies, like M 82, the flattening due to absorption is instead visible up to higher frequencies of about 150 MHz. Starbursts are however scarce in the local Universe, in accordance with the weak spectral curvature seen in the galaxies of our sample. Locally, within galactic disks, the absorption effects are distinctly visible in M 51-like galaxies as spectral flattening around 100-200 MHz in the face-on objects, and as turnovers in the edge-on ones, while in M 82-like galaxies there are strong turnovers at frequencies above 700 MHz, regardless of viewing angle. Conclusions. Our modelling of galaxy spectra suggests that the weak spectral flattening observed in the nearby galaxies studied here results principally from synchrotron spectral curvature due to cosmic ray energy losses and propagation effects. We predict much stronger effects of thermal absorption in more distant galaxies with high star formation rates. Some influence exerted by the Milky Way's foreground on the spectra of all external galaxies is also expected at very low frequencies.Peer reviewedFinal Accepted Versio
Syntactic Markovian Bisimulation for Chemical Reaction Networks
In chemical reaction networks (CRNs) with stochastic semantics based on
continuous-time Markov chains (CTMCs), the typically large populations of
species cause combinatorially large state spaces. This makes the analysis very
difficult in practice and represents the major bottleneck for the applicability
of minimization techniques based, for instance, on lumpability. In this paper
we present syntactic Markovian bisimulation (SMB), a notion of bisimulation
developed in the Larsen-Skou style of probabilistic bisimulation, defined over
the structure of a CRN rather than over its underlying CTMC. SMB identifies a
lumpable partition of the CTMC state space a priori, in the sense that it is an
equivalence relation over species implying that two CTMC states are lumpable
when they are invariant with respect to the total population of species within
the same equivalence class. We develop an efficient partition-refinement
algorithm which computes the largest SMB of a CRN in polynomial time in the
number of species and reactions. We also provide an algorithm for obtaining a
quotient network from an SMB that induces the lumped CTMC directly, thus
avoiding the generation of the state space of the original CRN altogether. In
practice, we show that SMB allows significant reductions in a number of models
from the literature. Finally, we study SMB with respect to the deterministic
semantics of CRNs based on ordinary differential equations (ODEs), where each
equation gives the time-course evolution of the concentration of a species. SMB
implies forward CRN bisimulation, a recently developed behavioral notion of
equivalence for the ODE semantics, in an analogous sense: it yields a smaller
ODE system that keeps track of the sums of the solutions for equivalent
species.Comment: Extended version (with proofs), of the corresponding paper published
at KimFest 2017 (http://kimfest.cs.aau.dk/
Novel P53 mutations detected by FAMA in colorectal cancers
Background: The aim of the study was to identify p53 gene mutations by FAMA (fluorescence-assisted mismatch
analysis) in colorectal cancers.
Patients and methods: Analytical scanning of the p53 gene (exons 5\u20139) was performed in colon cancer samples
from 44 consecutive patients by FAMA. FAMA is a semiautomatic scanning approach based on the chemical cleavage
of the mismatch in fluorescently labeled heteroduplex DNA, obtained from the combination of a normal and a mutated
allele. FAMA has already shown optimal levels of diagnostic accuracy and sensitivity in detecting gene mutations
(nucleotide substitutions, insertions/deletions) both at the germline and somatic level. The peculiar feature of FAMA is
its ability to detect and localize mutations, by a redundant pattern of signals due to fluorescent DNA fragments
generated by chemical cleavage. Moreover, previous data have demonstrated that normal contaminating DNA from
stromal cells in the sample does not affect the sensitivity of the procedure, leading to the identification of the mutation
even when the ratio mutant/normal allele is 10%.
Results: Eighteen mutations (12 missense, one nonsense, two deletions, three nucleotide substitutions at the level of
the splice-junctions) and two polymorphisms were detected by FAMA in 17 patients (39%) and then confirmed by
automated sequence analysis. Six of 18 mutations (33%) were not previously reported for colon cancer samples and
two of 18 lesions (11%) were identified as novel p53 mutations.
Conclusions: Analytical scanning of the p53 gene by FAMA in DNA from colon cancer samples provides a sensitive,
accurate and specific diagnostic procedure for routine clinical application
Polarized point sources in the LOFAR Two-meter Sky Survey: A preliminary catalog
The polarization properties of radio sources at very low frequencies (h45m–15h30m right ascension, 45°–57° declination, 570 square degrees). We have produced a catalog of 92 polarized radio sources at 150 MHz at 4.′3 resolution and 1 mJy rms sensitivity, which is the largest catalog of polarized sources at such low frequencies. We estimate a lower limit to the polarized source surface density at 150 MHz, with our resolution and sensitivity, of 1 source per 6.2 square degrees. We find that our Faraday depth measurements are in agreement with previous measurements and have significantly smaller errors. Most of our sources show significant depolarization compared to 1.4 GHz, but there is a small population of sources with low depolarization indicating that their polarized emission is highly localized in Faraday depth. We predict that an extension of this work to the full LOTSS data would detect at least 3400 polarized sources using the same methods, and probably considerably more with improved data processing
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