1,721,042 research outputs found
Occlusion and Back Pain: Reality and Prejudice
No full textIt has often been suggested that patients with a temporomandibular disorder more often suffer from a cervical spine disorder and/or back pain and the aim of the paper is to review the international literature on the relationship between dental occlusion, body posture, and temporomandibular disorders related to
back pain. The three main research field found in literature are: the functional anatomy and physiology of the dental occlusionbody
posture relationship and their relationship with temporomandibular disorders, the validity of the instrumental devices to measure the dental occlusion-body posture and the correlation between the orofacial area and the cervical spine in the biopsychosocial approach for chronic pain. Literature showed that even if some associations have been found between occlusal factors and postural alterations, there is not enough scientific evidence to support a cause effect relation and also in the Evidence Based Medicine analysis, there is no evidence that support the relationship between occlusal features and the presence of back pain
Spiral Constellations for Phase Noise Channels
Full text linkIn this paper, we consider the design of spiral constellations for channels affected by phase noise. The strength of the proposed constellations resides both on the performance and on the extreme simplicity of the design. The symbols can in fact be expressed in analytical form, and are uniquely defined through a single parameter that accounts for the phase and thermal noise variances. The structure of the proposed constellations allows to easily determine the points that are closest to any point in the complex plane, therefore we also propose a low complexity detector that is suitable for phase noise channels in medium-high signal-to-noise ratio conditions. The performance of the proposed constellations are assessed in terms of information rate and error rate. Despite their simplicity, the new spiral constellations have excellent performance, especially when the constellation size grows large
Dental open bite caused by finger resolved by functional appliance
No full textThe Authors present the treatment of a skeletal and dental open bite by oral habit of finger sucking. The patient is treated with functonal appliance, getting the complete lost of oral habit and partially resolving the malocclusion
MAXILLARY DENTO-SKELETAL OUTCOMES AFTER EN MASSE ORTHOPEDIC FORWARD (CLASS III) AND BACKWARD (CLASS II) TRACTION IN GROWING SUBJECTS
No full textvengono messe a confronto due trazioni di verso opposto del mascellare, in avanti (classe III) ed in dietro (classe II), con risultati e valutazioni statistiche e clinich
Channel Characterisation for Underwater Optical Wireless Vertical Links
Full text linkWe provide a detailed description of depth-dependent effects that affect the propagation of light in underwater optical wireless communication links. Absorption and scattering properties of water are evaluated for realistic chlorophyll profiles versus depth for all the visible spectrum, with particular attention to the wavelengths corresponding to practically feasible laser sources. Results show which visible wavelength is the less affected by propagation loss in specific water conditions, thus being the most suitable to improve the performance of vertical links in underwater optical wireless communications. The developed model is useful also to optimise the distribution of optical channels in systems based on dense wavelength division multiplexing technology, according to the type of water and the depth reached in the vertical communication link
Do changes in spheno-occipital synchondrosis after rapid maxillary expansion affect the maxillomandibular complex?
No full textThis was to evaluate changes in spheno-occipital synchondrosis one year after rapid maxillary expansion (RME), in order to assess the influence that any change might have on sagittal and vertical skeletal cephalometric variables
Advanced techniques for spectrally efficient DVB-S2X systems
No full textWe investigate different techniques to improve the spectral efficiency of systems based on the DVB-S2 standard, when the transmitted signal bandwidth cannot be increased because it has already been optimized to the maximum value allowed by transponder filters. We will investigate and compare several techniques involving different sections of the transceiver scheme. The techniques that will be considered include the use of advanced detection algorithms, the adoption of time packing, and the optimization of the constellation and shaping pulses. The low-density parity-check codes recently proposed for the evolution of the DVB-S2 standard will be considered, as well as the adoption of iterative detection and decoding. Information-theoretical analysis will be followed by the study of practical modulation and coding schemes. Copyright © 2015 John Wiley & Sons, Ltd
A system level approach to the application of multiuser detection in multibeam satellite systems
No full textWe study the performance of a multibeam satellite
system under different frequency reuse schemes. We provide an
information theoretical framework to analyze the achievable rates
in two beams sharing the same frequency, based on single-user
and multiuser detection. We compare two alternative strategies
to serve two users in two beams, showing that interesting gains
are possible by using multiuser detection and a higher frequency
reuse scheme
Next Generation High-Rate Telemetry
No full textRecent investigations show that high-rate telemetry systems, based on the CCSDS 131.2-B-1 standard and employed in Earth observation missions, do not fully exploit the available capacity. We thus propose and discuss possible ways to improve the data return of these systems that can be considered for a revision of the current standard. Some of them are represented by a revision and/or an extension of the currently adopted modulation and coding formats. The remaining techniques are related to an enhancement of the transceiver architecture. Different bandwidth allocation strategies are also considered. The benefits of the proposed techniques are assessed by means of computer simulations with reference to a realistic scenario where a real nonlinear amplifier, real filters, and real impairments are considered
On the Use of Multiple Satellites to Improve the Spectral Efficiency of Broadcast Transmissions
Full text linkWe consider the use of multiple co-located satellites to improve the spectral efficiency of broadcast transmissions. In particular, we assume that two satellites transmit on overlapping geographical coverage areas, with overlapping frequencies. We first describe the theoretical framework based on network information theory and, in particular, on the theory for multiple access channels. The application to different scenarios will be then considered, including the bandlimited additive white Gaussian noise channel with average power constraint and different models for the nonlinear satellite channel. The comparison with the adoption of frequency division multiplexing and with the Alamouti space-time block coding is also provided. The main conclusion is that a strategy based on overlapped signals is the most convenient in the case of no power unbalance, although it requires the adoption of a multiuser detection strategy at the receiver
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