A network analysis on cloud gaming: Stadia, GeForce Now and PSNow

Cloud gaming is a new class of services that promises to revolutionize the videogame market. It allows the user to play a videogame with basic equipment while using a remote server for the actual execution. The multimedia content is streamed through the network from the server to the user. This service requires low latency and a large bandwidth to work properly with low response time and high-definition video. Three of the leading tech companies, (Google, Sony and NVIDIA) entered this market with their own products, and others, like Microsoft and Amazon, are planning to launch their own platforms in the near future. However, these companies released so far little information about their cloud gaming operation and how they utilize the network. In this work, we study these new cloud gaming services from the network point of view. We collect more than 200 packet traces under different application settings and network conditions for 3 cloud gaming services, namely Stadia from Google, GeForce Now from NVIDIA and PS Now from Sony. We analyze the employed protocols and the workload they impose on the network. We find that GeForce Now and Stadia use the RTP protocol to stream the multimedia content, with the latter relying on the standard WebRTC APIs. They result in bandwidth-hungry and consume up to 45 Mbit/s, depending on the network and video quality. PS Now instead uses only undocumented protocols and never exceeds 13 Mbit/s

Experimental Evaluation of Metallic Coating on Polymer by Cold Spray

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Deep optical observations of the central X-ray source in the Puppis A supernova remnant

X-ray observations reveiled a group of radio-silent isolated neutron stars (INSs) at the centre of young supernova remnants (SNRs), dubbed central compact objects or CCOs, with properties different from those of classical rotation-powered pulsars. In at least three cases, evidence points towards CCOs being low-magnetized INSs, born with slow rotation periods, and possibly accreting from a debris disc of material formed out of the supernova event. Understanding the origin of the diversity of the CCOs can shed light on supernova explosion and neutron star formation models. Optical/infrared (IR) observations are crucial to test different CCO interpretations. The aim of our work is to perform a deep optical investigation of the CCO RX J0822.0-4300 in the Puppis A SNR, one of the most poorly understood in the CCO family. By using as a reference the Chandra X-ray coordinates of RX J0822.0-4300, we performed deep optical observations in the B, V and I bands with the Very Large Telescope (VLT). We found no candidate optical counterpart within 3 sigma of the computed Chandra X-ray position down to 5 sigma limits of B~27.2, V~26.9, and I~25.6, the deepest obtained in the optical band for this source. These limits confirm the non-detection of a companion brighter than an M5 dwarf. At the same time, they do not constrain optical emission from the neutron star surface, while emission from the magnetosphere would require a spectral break in the optical/IR.Comment: 4 pages, 2 figures, Astronomy and Astrophysics, accepte

Advancing the interfacing performances of chronically implantable neural probes in the era of CMOS neuroelectronics

Tissue penetrating microelectrode neural probes can record electrophysiological brain signals at resolutions down to single neurons, making them invaluable tools for neuroscience research and Brain-Computer-Interfaces (BCIs). The known gradual decrease of their electrical interfacing performances in chronic settings, however, remains a major challenge. A key factor leading to such decay is Foreign Body Reaction (FBR), which is the cascade of biological responses that occurs in the brain in the presence of a tissue damaging artificial device. Interestingly, the recent adoption of Complementary Metal Oxide Semiconductor (CMOS) technology to realize implantable neural probes capable of monitoring hundreds to thousands of neurons simultaneously, may open new opportunities to face the FBR challenge. Indeed, this shift from passive Micro Electro-Mechanical Systems (MEMS) to active CMOS neural probe technologies creates important, yet unexplored, opportunities to tune probe features such as the mechanical properties of the probe, its layout, size, and surface physicochemical properties, to minimize tissue damage and consequently FBR. Here, we will first review relevant literature on FBR to provide a better understanding of the processes and sources underlying this tissue response. Methods to assess FBR will be described, including conventional approaches based on the imaging of biomarkers, and more recent transcriptomics technologies. Then, we will consider emerging opportunities offered by the features of CMOS probes. Finally, we will describe a prototypical neural probe that may meet the needs for advancing clinical BCIs, and we propose axial insertion force as a potential metric to assess the influence of probe features on acute tissue damage and to control the implantation procedure to minimize iatrogenic injury and subsequent FBR

Discovery of a 112 ms X-ray Pulsar in Puppis A: Further Evidence of Neutron Stars Weakly Magnetized at Birth

We report the discovery of 112-ms X-ray pulsations from RX J0822-4300, the compact central object (CCO) in the supernova remnant Puppis A, in two archival Newton X-Ray Multi-Mirror Mission observations taken in 2001. The sinusoidal light curve has a pulsed fraction of 11% with an abrupt 180 deg. change in phase at 1.2 keV. The observed phase shift and modulation are likely the result of emission from opposing thermal hot spots of distinct temperatures. Phase-resolved spectra reveal an emission feature at E(line) = 0.8 keV associated with the cooler region, possibly due to an electron cyclotron resonance effect similar to that seen in the spectrum of the CCO pulsar 1E 1207.4-5209. No change in the spin period of PSR J0821-4300 is detected in 7 months, with a 2 sigma upper limit on the period derivative less than 8.3E-15. This implies limits on the spin-down energy loss rate of less than 2.3E35 erg/s, the surface magnetic dipole field strength B_s < 9.8E11 G, and the spin-down age tau > 220 kyr. The latter is much longer than the SNR age, indicating that PSR J0821-4300 was born spinning near its present period. Its properties are remarkably similar to those of the two other known CCO pulsars, demonstrating the existence of a class of neutron stars born with weak magnetic fields related to a slow original spin. These results are also of importance in understanding the extreme transverse velocity of PSR J0821-4300, favoring the hydrodynamic instability mechanism in the supernova explosion.Comment: 5 pages, 4 figure, Latex, emulateapj style. To appear in the Astrophysical Journa

Spontaneous vertebral aspergillosis, the state of art: a systematic literature review

Objective: Vertebral aspergillosis are quite rare conditions, often misdiagnosed, that requires long-term antibiotic therapy and, sometimes, surgical treatments. The present investigations was aimed to investigate epidemiology, clinical-radiological aspects, treatment protocols, and outcomes of Aspergillus-mediated vertebral osteomyelitis. Methods: A systematic review of the pertinent English Literature according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was performed. The research was conducted on Cochrane library, MEDLINE, PubMed and Scopus using as search-terms “Aspergillus”, “vertebral osteomyelitis”, “spondylodiscitis”, “spine infection”. A case of vertebral apsergillosis conservatively managed was also reported. Results: Eighty-nine articles were included in our systematic review. Including the reported case, our analysis covered 112 cases of vertebral aspergillosis. Aspergillus fumigatus was isolated in 68 cases (61.2%), Aspergillus flavus in 14 (12.6%), Aspergillus terreus in 4 (3.6%), Aspergillus nidulans in 2 (1.8%). Seventy-three patients (65.7%) completely recovered at last follow-up evaluation; in 7 (6.3%) patients radiological signs of chronic infection were reported, whereas 32 (28.8%) patients died during the follow-up. Conclusion: This systematic review summarized the state of the art on vertebral aspergillosis, retrieving data on clinical features, diagnostic criteria and current limitations, treatment alternatives and their outcomes