368 research outputs found
5G Wireless Network Slicing for eMBB, URLLC, and mMTC: A Communication-Theoretic View
The grand objective of 5G wireless technology is to support three generic
services with vastly heterogeneous requirements: enhanced mobile broadband
(eMBB), massive machine-type communications (mMTC), and ultra-reliable
low-latency communications (URLLC). Service heterogeneity can be accommodated
by network slicing, through which each service is allocated resources to
provide performance guarantees and isolation from the other services. Slicing
of the Radio Access Network (RAN) is typically done by means of orthogonal
resource allocation among the services. This work studies the potential
advantages of allowing for non-orthogonal sharing of RAN resources in uplink
communications from a set of eMBB, mMTC and URLLC devices to a common base
station. The approach is referred to as Heterogeneous Non-Orthogonal Multiple
Access (H-NOMA), in contrast to the conventional NOMA techniques that involve
users with homogeneous requirements and hence can be investigated through a
standard multiple access channel. The study devises a communication-theoretic
model that accounts for the heterogeneous requirements and characteristics of
the three services. The concept of reliability diversity is introduced as a
design principle that leverages the different reliability requirements across
the services in order to ensure performance guarantees with non-orthogonal RAN
slicing. This study reveals that H-NOMA can lead, in some regimes, to
significant gains in terms of performance trade-offs among the three generic
services as compared to orthogonal slicing.Comment: Submitted to IEE
Reliable Transmission of Short Packets through Queues and Noisy Channels under Latency and Peak-Age Violation Guarantees
This work investigates the probability that the delay and the peak-age of
information exceed a desired threshold in a point-to-point communication system
with short information packets. The packets are generated according to a
stationary memoryless Bernoulli process, placed in a single-server queue and
then transmitted over a wireless channel. A variable-length stop-feedback
coding scheme---a general strategy that encompasses simple automatic repetition
request (ARQ) and more sophisticated hybrid ARQ techniques as special
cases---is used by the transmitter to convey the information packets to the
receiver. By leveraging finite-blocklength results, the delay violation and the
peak-age violation probabilities are characterized without resorting to
approximations based on large-deviation theory as in previous literature.
Numerical results illuminate the dependence of delay and peak-age violation
probability on system parameters such as the frame size and the undetected
error probability, and on the chosen packet-management policy. The guidelines
provided by our analysis are particularly useful for the design of low-latency
ultra-reliable communication systems.Comment: To appear in IEEE journal on selected areas of communication (IEEE
JSAC
Modern technologies in Endodontics
AbstractAimIn Endodontics, a complete chemo-mechanical cleansing of the root canal system is essential to achieving success, which is gained through adequate tridimensional obturation of the endodontic space.Materials and methodsToday, thanks to modern technologies as Operative Microscope, ultrasonic tips, M-Wire Files, devices to activate irrigation and tridimensional obturation performed with thermo plasticized gutta-percha, satisfactory results can be obtained.ResultsThis study shows all the technologies that are available today to increase the chemo-mechanical cleansing and obturation of the entire and complicated endodontic system.ConclusionsThe positive results highlighted by these clinical cases demonstrate how the use of modern technologies are essential to avoid iatrogenic injury, and guarantee, on the other hand, safe and reproducible results
Modern technologies in Endodontics
Abstract Aim In Endodontics, a complete chemo-mechanical cleansing of the root canal system is essential to achieving success, which is gained through adequate tridimensional obturation of the endodontic space. Materials and methods Today, thanks to modern technologies as Operative Microscope, ultrasonic tips, M-Wire Files, devices to activate irrigation and tridimensional obturation performed with thermo plasticized gutta-percha, satisfactory results can be obtained. Results This study shows all the technologies that are available today to increase the chemo-mechanical cleansing and obturation of the entire and complicated endodontic system. Conclusions The positive results highlighted by these clinical cases demonstrate how the use of modern technologies are essential to avoid iatrogenic injury, and guarantee, on the other hand, safe and reproducible results
Territorial Ecosystem for circular economies: Eco3R research project
Among the transitional processes that could lead to building consistent sustainable solutions, circular economies practices (CE) are complex processes which must take into account diff erent topics such as stakeholder engagement, material fl ows opportunities, end of life expectations and EU limit perspectives or targets.
This paper introduces briefl y the concept of circular territorial ecosystems with respect to the Eco3r research project, carried on by the Politecnico of Turin (DAD) from 2020, in collaboration with CCS, the in-house providing company of 19 municipalities in the area of Turin. Some crucial data on waste management and the main project’s targets are presented. Some Eco3r projects’ outputs are outlined in order to show this local experiment can become a model to scale or replicate in other communities in Europe.
The paper is structured as follows: Section 1 describes the background problem with main data and critical issues regarding the case study; Section 2 is describing the target of the research project Eco3R and the scientifi c approach adopted; Section 3 is dedicated on the main output of Eco3R project and the discussion on the further research developments
Anaerobic Digestion of Olive Mill Wastewater in the Presence of Biochar
Biological treatments focused on stabilizing and detoxifying olive mill wastewater facilitate agronomic reuse for irrigation and fertilization. Anaerobic digestion is particularly attractive in view of energy recovery, but is severely hampered by the microbial toxicity of olive mill wastewater. In this work, the addition of biochar to the digestion mixture was studied to improve the stability and efficiency of the anaerobic process. Kinetics and yields of biogas production were evaluated in batch digestion tests with biochar concentrations ranging from 0 to 45 g L−1. The addition of biochar reduced sensibly the lag phase for methanogenesis and increased the maximum rate of biogas generation. Final yields of hydrogen and methane were not affected. Upon addition of biochar, soluble COD removal increased from 66% up to 84%, and phenolics removal increased from 50% up to 95%. Digestate phytotoxicity, as measured by seed germination tests, was reduced compared to raw wastewater. Addition of biochar further reduced phytotoxicity and, furthermore, a stimulatory effect was observed for a twenty-fold dilution. In conclusion, biochar addition enhances the anaerobic digestion of olive mill wastewaters by effectively reducing methanogenesis inhibition and digestate phytotoxicity, thus improving energy and biomass recovery
Biochar-based remediation of water and soils contaminated by organic compounds
Biochar is a carbonaceous material obtained by pyrolysis of vegetable biomasses. Due to its nature, biochar can be used as soil amendment to increase soil fertility and to mitigate climate change. In addition its particular porous structure and high specific surface area make it a very effective sorbent for organic and inorganic contaminant in soil and water. Therefore, the aim of this thesis was to evaluate the efficiency of poplar and conifer biochars in remediation of i) water and soil contaminated by phenanthrene (Phe) and pentachlorophenol (PCP) and ii) olive mill wastewater (OMW). Biochar from conifer removed more successfully contaminant molecules in Phe and PCP contaminated water solution also when it was confined in dialysis tube. Greater efficiency of conifer biochar was observed also in the treatment of contaminated soil leading to the consequent reduction of soil phytotoxicity. Conversely, biochar from poplar better performed the OMW remediation resulting in the reduction of total phenols (up to 72%) and phytotoxicity. Furthermore, soil amended with treated OMW showed beneficial changes in chemical and biochemical soil properties.
The aim of this thesis was also to establish an improved analysis method for black carbon metabolites measurements using ion chromatography in order to have information about the fate of black carbon (biochar) in soil. Black carbon metabolites are ubiquitous in soil like black carbon itself. However, black carbon concentration in soil is no good predictor about fate of black carbon degradation. Rather, physical, chemical and probably also biological soil properties yet to be identified, to control black carbon metabolism in soil
Nonsurgical management of complex endodontic cases with several periapical lesions: a case series
Abstract Aim Today, thanks to modern technologies as operative microscope, ultrasonic tips, devices to activate irrigation and tridimensional obturation performed with thermo plasticized gutta-percha, excellent results could be obtained. Materials and methods In this study, we present 5 patients with the presence of periapical lesions in molars and incisors with history of pain. Modern endodontic technologies were used. The rationale of using these technologies was to obtain a chemo-mechanical cleansing and obturation of the entire endodontic system and to gain the lesion resolution with a non-surgical approach. Results A success rate of 100% was obtained. Radiographs and clinical examinations were done until 10 years. All the cases highlighted the success achieved in the short and long term through the complete resolution of the lesions and therefore the reconstitution of the lamina dura. Conclusions The positive results highlighted by these clinical cases demonstrate how the use of modern technologies is essential to avoid iatrogenic damage and to gain safe and reproducible results
Raw meat based diet influences faecal microbiome and end products of fermentation in healthy dogs
Background: Dietary intervention studies are required to deeper understand the variability of gut microbial ecosystem in healthy dogs under different feeding conditions and to improve diet formulations. The aim of the study was to investigate in dogs the influence of a raw based diet supplemented with vegetable foods on faecal microbiome in comparison with extruded food.
Methods: Eight healthy adult Boxer dogs were recruited and randomly divided in two experimental blocks of 4 individuals. Dogs were regularly fed a commercial extruded diet (RD) and starting from the beginning of the trial, one group received the raw based diet (MD) and the other group continued to be fed with the RD diet (CD) for a fortnight. After 14 days, the two groups were inverted, the CD group shifted to the MD and the MD shifted to the CD, for the next 14 days. Faeces were collected at the beginning of the study (T0), after 14 days (T14) before the change of diet and at the end of experimental period (T28) for DNA extraction and analysis of metagenome by sequencing 16SrRNA V3 and V4 regions, short chain fatty acids (SCFA), lactate and faecal score.
Results: A decreased proportion of Lactobacillus, Paralactobacillus (P < 0.01) and Prevotella (P < 0.05) genera was observed in the MD group while Shannon biodiversity Index significantly increased (3.31 +/- 0.15) in comparison to the RD group (2.92 +/- 0.31; P < 0.05). The MD diet significantly (P < 0.05) decreased the Faecal Score and increased the lactic acid concentration in the feces in comparison to the RD treatment (P < 0.01). Faecal acetate was negatively correlated with Escherichia/Shigella and Megamonas (P < 0.01), whilst butyrate was positively correlated with Blautia and Peptococcus (P < 0.05). Positive correlations were found between lactate and Megamonas (P < 0.05), Escherichia/Shigella (P < 0.01) and Lactococcus (P < 0.01).
Conclusion: These results suggest that the diet composition modifies faecal microbial composition and end products of fermentation. The administration of MD diet promoted a more balanced growth of bacterial communities and a positive change in the readouts of healthy gut functions in comparison to RD diet
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