112 Hits in 0.96 sec

Citizen COmputing for Pulsar Searches: CICLOPS [article]

Matteo Bachetti
2020 arXiv   pre-print
Most periodicity search algorithms used in pulsar astronomy today are highly efficient and take advantage of multiple CPUs or GPUs. The bottlenecks are usually represented by the operations that require an informed choice from an expert eye. A typical case is the presence of radio-frequency interferences in the data, that often mimic the periodic signals of pulsars, and require visual inspection of hundreds or thousands of pulsar "candidates" satisfying a number of preselected criteria. CICLOPS
more » ... is a citizen science project designed to transform the search for pulsars into an entertaining 3D video game. We build a distributed computing platform, running calculations with the user's CPUs and GPUs and using the unique human abilities in pattern recognition to find the best candidate pulsations.
arXiv:2012.12629v1 fatcat:quhwc5pcdzcpxgjlon7y2vsk4q

Hard X-ray flares and spectral variability in NGC 4395 ULX1 [article]

Tanuman Ghosh, Vikram Rana, Matteo Bachetti
2022 arXiv   pre-print
Tools like HEN-DRICS (Bachetti 2018) and PRESTO (Ransom 2011) are employed for these tasks. However, no significant pulsation is detected in any epoch.  ...  Indeed a number of ULXs were found to have neutron star accretors, confirming this super-Eddington interpretation (Bachetti et al. 2014; Fürst et al. 2016; Israel et al. 2017a,b; Brightman et al. 2018  ... 
arXiv:2202.01432v1 fatcat:a7xuqo4pfzfdnlxiwfjwlzm4ke

Timing Calibration of the NuSTAR X-ray Telescope [article]

Matteo Bachetti
2020 arXiv   pre-print
The presence of two identical detectors in NuSTAR allows to partly work around the problem (Bachetti et al. 2015; Bachetti & Huppenkothen 2018) .  ...  NuSTAR TIME TAGGING DETAILS The method used to assign photon arrival times on the spacecraft for NuSTAR detector events is described in detail in Madsen et al. (2015) ; Bachetti et al. (2015) .  ... 
arXiv:2009.10347v2 fatcat:hqti7l7jdzf4vgptqnhecqmnqe

The Moving Hotspots model for kHz QPOs in accreting neutron stars [article]

Matteo Bachetti Cornell University)
2010 arXiv   pre-print
3D MHD simulation of accretion onto neutron stars have shown in the last few years that the footprint (hotspot) of the accretion flow changes with time. Two different kinds of accretion, namely the funnel flow and the equatorial accretion produced by instabilities at the inner disk, produce different kinds of motion of the hotspot. The funnel flow produces hotspots that move around the magnetic pole, while instabilities produce other hotspots that appear randomly and move along the equator or
more » ... ightly above. The angular velocities of the two hotspots are different, the equatorial one being higher and both close to the Keplerian velocity in the inner region. Modeling of the lightcurves of these hotspots with Monte Carlo simulations show that the signatures produced in power specra by them, if observed, are QPOs plus low frequency components. Their frequencies, general behavior and features describe correctly most of the properties of kHz QPOs, if we assume the funnel flow hotspots as the origin of the lower kHz QPO and instabilities as the origin of the upper kHz QPO.
arXiv:1011.0142v1 fatcat:elauy5poc5gytcrzaydkysq6yq

Impact of Nutritional Supplementation on Canine Dermatological Disorders

Andrea Marchegiani, Alessandro Fruganti, Andrea Spaterna, Elena Dalle Vedove, Benedetta Bachetti, Marcella Massimini, Francesco Di Pierro, Alessandra Gavazza, Matteo Cerquetella
2020 Veterinary Sciences  
Nutritional supplements, also known as complementary feeds, are products administered with the aim of furnishing health benefits, regardless of nutritional needs. They have been used since ancient times in veterinary dermatology, and a number of studies have focused on investigating the health benefits of some ingredients found in commercially available complementary feed for dogs. The aim of this paper is to review the literature available on the use of nutritional supplementation for the
more » ... ement of canine skin diseases, critically appraising the clinical efficacy of such interventions and summarizing the current state of knowledge. This review highlights how these feeds can be considered useful in the management of dermatological disorders and outlines their beneficial effects in the prevention of dietary deficiencies and treatment of diseases, alone, or in addition to conventional pharmacological therapy. In recent years, nutritional supplements have found increasing potential application in veterinary medicine, and the scientific proofs of their beneficial effects are described in this review.
doi:10.3390/vetsci7020038 pmid:32260299 pmcid:PMC7355824 fatcat:2y5e522o45dyhdcywsw6zcvavq

A multi-wavelength pipeline for pulsar observations

Maura Pilia, Alessio Trois, Matteo Bachetti, Alberto Pellizzoni, Elise Egron, Maria Noemi Iacolina, Sara Loru
2017 Proceedings of the International Astronomical Union  
AbstractThe Astronomical Observatory in Cagliari (OAC) is a growing facility with a group devoted to pulsar studies across the electromagnetic spectrum. Taking advantage of this expertise we have worked to provide a suite of multi-wavelength software and databases for the observations of pulsars and compact Galactic objects at the Sardinia Radio Telescope (SRT, Bolli et al. 2015, Prandoni et al. 2017).
doi:10.1017/s1743921317008687 fatcat:gjp3mvap65h3zapwmbmqk2tmhq

Functional Conservation and Genetic Divergence of Chordate Glycinergic Neurotransmission: Insights from Amphioxus Glycine Transporters

Matteo Bozzo, Simone Costa, Valentina Obino, Tiziana Bachetti, Emanuela Marcenaro, Mario Pestarino, Michael Schubert, Simona Candiani
2021 Cells  
Glycine is an important neurotransmitter in vertebrates, performing both excitatory and inhibitory actions. Synaptic levels of glycine are tightly controlled by the action of two glycine transporters, GlyT1 and GlyT2, located on the surface of glial cells and neurons, respectively. Only limited information is available on glycinergic neurotransmission in invertebrates, and the evolution of glycinergic neurotransmission is poorly understood. Here, by combining phylogenetic and gene expression
more » ... lyses, we characterized the glycine transporter complement of amphioxus, an important invertebrate model for studying the evolution of chordates. We show that amphioxus possess three glycine transporter genes. Two of these (GlyT2.1 and GlyT2.2) are closely related to GlyT2 of vertebrates, whereas the third (GlyT) is a member of an ancestral clade of deuterostome glycine transporters. GlyT2.2 expression is predominantly non-neural, whereas GlyT and GlyT2.1 are widely expressed in the amphioxus nervous system and are differentially expressed, respectively, in neurons and glia. Vertebrate glycinergic neurons express GlyT2 and glia GlyT1, suggesting that the evolution of the chordate glycinergic system was accompanied by a paralog-specific inversion of gene expression. Despite this genetic divergence between amphioxus and vertebrates, we found strong evidence for conservation in the role glycinergic neurotransmission plays during larval swimming, the implication being that the neural networks controlling the rhythmic movement of chordate bodies may be homologous.
doi:10.3390/cells10123392 pmid:34943900 pmcid:PMC8699752 fatcat:44oxqcfkofghxi2jnp2b3s2qca

Stingray: A Modern Python Library for Spectral Timing

Daniela Huppenkothen, Matteo Bachetti, Abigail L. Stevens, Simone Migliari, Paul Balm, Omar Hammad, Usman Mahmood Khan, Himanshu Mishra, Haroon Rashid, Swapnil Sharma, Evandro Martinez Ribeiro, Ricardo Valles Blanco
2019 Astrophysical Journal  
.; Bachetti, M.; Stevens, A. L.; Migliari, S.; Balm, P.; Hammad, O.; Khan, U. M.; Mishra, H.; Rashid, H.; Sharma, S.  ...  HENDRICS (Bachetti 2015a ; see also Section 9) provides prebuilt data analysis workflows using stingray core functionality.  ...  Please note that as laid out in Huppenkothen & Bachetti (2017) , these distribution are not appropriate for use on (averaged) cross spectra.  ... 
doi:10.3847/1538-4357/ab258d fatcat:wlnzmemi2zhg7prmi3s3nhhxni

Extending the Z^2_n and H statistics to generic pulsed profiles [article]

Matteo Bachetti
2021 arXiv   pre-print
Software: Stingray (Huppenkothen et al. 2016, 2019), HENDRICS (Bachetti 2018), astropy (Astropy Collaboration et al. 2018), PINT (Luo et al. 2019), ATNF pulsar catalogue (Manchester et al. 2005), PRESTO  ... 
arXiv:2012.11397v2 fatcat:a7aaahqy2ndihdyzdeh27u35im

3D MHD Simulations of accreting neutron stars: evidence of QPO emission from the surface [article]

Matteo Bachetti, Luciano Burderi Università degli Studi di Cagliari,
2009 arXiv   pre-print
3D Magnetohydrodynamic simulations show that when matter accretes onto neutron stars, in particular if the misalignment angle is small, it does not constantly fall at a fixed spot. Instead, the location at which matter reaches the star moves. These moving hot spots can be produced both during stable accretion, where matter falls near the magnetic poles of the star, and unstable accretion, characterized by the presence of several tongues of matter which fall on the star near the equator, due to
more » ... ayleigh-Taylor instabilities. Precise modeling with Monte Carlo simulations shows that those movements could be observed as high frequency Quasi Periodic Oscillations. We performed a number of new simulation runs with a much wider set of parameters, focusing on neutron stars with a small misalignment angle. In most cases we observe oscillations whose frequency is correlated with the mass accretion rate Ṁ. Moreover, in some cases double QPOs appear, each of them showing the same correlation with Ṁ.
arXiv:0912.0234v1 fatcat:vjbkuj6tejg5flw3cgizch6nsu

stingray: A modern Python library for spectral timing

Daniela Huppenkothen, Matteo Bachetti, Abigail Stevens, Simone Migliari, Paul Balm, Omar Hammad, Usman Khan, Himanshu Mishra, Haroon Rashid, Swapnil Sharma, Evandro Ribeiro, Ricardo Blanco
2019 Journal of Open Source Software  
.; Bachetti, M.; Stevens, A. L.; Migliari, S.; Balm, P.; Hammad, O.; Khan, U. M.; Mishra, H.; Rashid, H.; Sharma, S.  ...  HENDRICS (Bachetti 2015a ; see also Section 9) provides prebuilt data analysis workflows using stingray core functionality.  ...  Please note that as laid out in Huppenkothen & Bachetti (2017) , these distribution are not appropriate for use on (averaged) cross spectra.  ... 
doi:10.21105/joss.01393 fatcat:e7mywjsoevfq5eu5botjtag5ha

Photospheric Radius Expansion and a double-peaked type-I X-ray burst from GRS 1741.9-2853 [article]

Sean N. Pike, Fiona A. Harrison, John A. Tomsick, Matteo Bachetti, Douglas J. K. Buisson, Javier A. García, Jiachen Jiang, R. M. Ludlam, Kristin K. Madsen
2021 arXiv   pre-print
We analyzed the cospectrum, the real part of the crossspectrum, due to its advantages described by Bachetti et al. (2015) , namely the fact that it eliminates contributions to the power spectrum introduced  ... 
arXiv:2106.13312v1 fatcat:4nk53ig7vbfuxn4qzziop26hi4

Modelling high-resolution spatially-resolved Supernova Remnant spectra with the Sardinia Radio Telescope [article]

Sara Loru, Alberto Pellizzoni, Elise Egron, Noemi Iacolina, Simona Righini, Marco Marongiu, Sara Mulas, Giulia Murtas, Davide Simeone, Maura Pilia, Matteo Bachetti, Alessio Trois (+2 others)
2016 arXiv   pre-print
Supernova Remnants (SNRs) exhibit spectra featured by synchrotron radio emission arising from the relativistic electrons, and high-energy emission from both leptonic (Bremsstrahlung and Inverse Compton) and hadronic processes (π^0 mesons decay) which are a direct signature of cosmic rays acceleration. Thanks to radio single-dish imaging observations obtained in three frequency bands (1.6, 7, 22 GHz) with the Sardinia Radio Telescope (, we can model different SNR regions
more » ... y. Indeed, in order to disentangle interesting and peculiar hadron contributions in the high-energy spectra (gamma-ray band) and better constrain SNRs as cosmic rays emitters, it is crucial to fully constrain lepton contributions first through radio-observed parameters. In particular, the Bremsstrahlung and Inverse Compton bumps observed in gamma-rays are bounded to synchrotron spectral slope and cut-off in the radio domain. Since these parameters vary for different SNR regions and electron populations, spatially-resolved radio spectra are then required for accurate multi-wavelength modelling.
arXiv:1609.03875v1 fatcat:5w4qvykzrbeldmxpt6auuigyqq

Alexander Disease Modeling in Zebrafish: An In Vivo System Suitable to Perform Drug Screening

Simona Candiani, Silvia Carestiato, Andreas F. Mack, Daniele Bani, Matteo Bozzo, Valentina Obino, Michela Ori, Francesca Rosamilia, Miriam De Sarlo, Mario Pestarino, Isabella Ceccherini, Tiziana Bachetti
2020 Genes  
Alexander disease (AxD) is a rare astrogliopathy caused by heterozygous mutations, either inherited or arising de novo, on the glial fibrillary acid protein (GFAP) gene (17q21). Mutations in the GFAP gene make the protein prone to forming aggregates which, together with heat-shock protein 27 (HSP27), αB-crystallin, ubiquitin, and proteasome, contribute to form Rosenthal fibers causing a toxic effect on the cell. Unfortunately, no pharmacological treatment is available yet, except for symptom
more » ... uction therapies, and patients undergo a progressive worsening of the disease. The aim of this study was the production of a zebrafish model for AxD, to have a system suitable for drug screening more complex than cell cultures. To this aim, embryos expressing the human GFAP gene carrying the most severe p.R239C under the control of the zebrafish gfap gene promoter underwent functional validation to assess several features already observed in in vitro and other in vivo models of AxD, such as the localization of mutant GFAP inclusions, the ultrastructural analysis of cells expressing mutant GFAP, the effects of treatments with ceftriaxone, and the heat shock response. Our results confirm that zebrafish is a suitable model both to study the molecular pathogenesis of GFAP mutations and to perform pharmacological screenings, likely useful for the search of therapies for AxD.
doi:10.3390/genes11121490 pmid:33322348 fatcat:rjwnn42frrfinap4i562yugocq

Short- and Long-Term Morbidity and Mortality in the Population Exposed to Dioxin after the "Seveso Accident"

2003 Industrial Health  
The early effects of 2,3,7,8-tetrachlorodibenzo-para-dioxin (TCDD) exposure in the population involved in the Seveso, Italy, incident in 1976, have been examined in numerous studies. Chloracne was the only effect linked with sufficient certainty to dioxin exposure. The possible longterm consequences were investigated with mortality and cancer incidence studies. Mortality and morbidity findings during the 20-year period following the accident showed increased risk from lymphoemopoietic neoplasm,
more » ... digestive system cancer (rectum in males, and biliary tract among females, in particular) and respiratory system cancer (lung, among males). In the incidence analyses, also thyroid gland and pleura cancer appeared suggestively increased. Soft tissue sarcomas showed an increase in the largest, yet least exposed, exposure sub-cohort. Several hypotheses associating non-cancer effects with dioxin exposure were corroborated by findings in the Seveso population: this was the case with cardiovascular effects (possibly linked to both chemical exposure and stressful disaster experience), endocrine effects (diabetes among females) and reproductive effects: exposure of men to TCDD was linked to a lowered male/female sex ratio in their offspring. The results of many Seveso studies point to possible gender effects, in accordance with animal models. Notwithstanding the acknowledged study limitations (lack of individual exposure markers, short latency, and small population size for certain cancer types), results of previous experimental and epidemiological studies, along with mechanistic knowledge on dioxin toxicity, support the hypotheses that the observed excesses might be associated with dioxin exposure. The mortality and cancer incidence follow-up of the Seveso cohort are continuing.
doi:10.2486/indhealth.41.127 pmid:12916742 fatcat:swkofnmbvbgrzaqkljp35tiqky
« Previous Showing results 1 — 15 out of 112 results