The separation of contributions from different sources in the magnetic field signal measured at satellite altitude is an open challenge. An approach to this problem, using Principal Component ...Analysis, is here applied to geomagnetic external field series at Virtual Observatories (VOs). These series are computed from an enlarged data set of Swarm data covering all local times and all geomagnetic activity levels between January 2014 and December 2019. For each 30‐day time window, the Equivalent Source Dipole technique is used to reduce all measurements inside a cylinder to one single “observation” at its axis and 500 km altitude. Our results reveal a first principal mode with dipolar geometry and time variation following very closely the RC‐index of geomagnetic activity. They display a resolved second principal mode with annual periodicity and of approximately zonal quadrupolar radial pattern, reminiscent of results in a previous study using VO series from a filtered satellite data set and with lower time resolution. We resort to the recent comprehensive model CM6 to identify a possible source for this second mode. We propose that the dipolar mode is the expression of the magnetospheric ring current dynamics, at 30‐day time resolution, and the quadrupolar mode is the expression of the annual asymmetry between local summer and winter Sq current vortices. Two fainter modes could be related to the equinoctial amplification of Sq vortices and the ionospheric dynamo modulation by nonmigrating tides. We show that a more uniform local time sampling could contribute to better resolve ionospheric structures.
Key Points
Dense grid of external field series computed at Virtual Observatories from Swarm data, with 30‐day time resolution
Principal Component Analysis tools recover a dominant zonal dipolar mode with sub‐annual variability strongly correlated with geomagnetic activity indices
A less well‐resolved mode shows a nearly equatorial wavenumber‐4 structure that peaks at the equinoxes
Observations of the geomagnetic field taken at Earth’s surface and at satellite altitude are combined to construct continuous models of the geomagnetic field and its secular variation from 1957 to ...2020. From these parent models, we derive candidate main field models for the epochs 2015 and 2020 to the 13th generation of the International Geomagnetic Reference Field (IGRF). The secular variation candidate model for the period 2020–2025 is derived from a forecast of the secular variation in 2022.5, which results from a multi-variate singular spectrum analysis of the secular variation from 1957 to 2020.
We present a 1‐D electrical conductivity profile of the Earth's mantle down to 2000 km derived from L1b Swarm satellite magnetic field measurements from November 2013 to September 2014. We first ...derive a model for the main magnetic field, correct the data for a lithospheric field model, and additionally select the data to reduce the contributions of the ionospheric field. We then model the primary and induced magnetospheric fields for periods between 2 and 256 days and perform a Bayesian inversion to obtain the probability density function for the electrical conductivity as function of depth. The conductivity increases by 3 orders of magnitude in the 400–900 km depth range. Assuming a pyrolitic mantle composition, this profile is interpreted in terms of temperature variations leading to a temperature gradient in the lower mantle that is close to adiabatic.
Key Points
Eletromagnetic induction from satellite data
Electrical conductivity of the Earth's mantle
Temperature gradient of the lower mantle
The problem of noncooperative resource allocation in multicell uplink orthogonal frequency division multiple access (OFDMA) systems is considered in this paper. Noncooperative games for subcarrier ...allocation and transmit power control are considered, aiming at maximizing the users' SINRs and, most notably, the users' energy efficiency, measured in bit/Joule and representing the number of error-free delivered bits for each Joule of energy used for transmission. The theory of potential games is used to come up with several noncooperative games admitting Nash equilibrium points. Since the proposed resource allocation games exhibit a computational complexity that may be in some cases prohibitive, approximate, reduced-complexity, implementations are also considered. For comparison purposes, some considerations on social-optimum solutions are also discussed. Numerical results confirm that the proposed resource allocation schemes are effective in increasing the network energy efficiency (as compared to rate-maximizing schemes), thus permitting to optimize the use of the energy stored in the battery. Moreover, the proposed approximate implementations exhibit a performance very close to that of the exact procedures.
In December 2019, the International Association of Geomagnetism and Aeronomy (IAGA) Division V Working Group (V-MOD) adopted the thirteenth generation of the International Geomagnetic Reference Field ...(IGRF). This IGRF updates the previous generation with a definitive main field model for epoch 2015.0, a main field model for epoch 2020.0, and a predictive linear secular variation for 2020.0 to 2025.0. This letter provides the equations defining the IGRF, the spherical harmonic coefficients for this thirteenth generation model, maps of magnetic declination, inclination and total field intensity for the epoch 2020.0, and maps of their predicted rate of change for the 2020.0 to 2025.0 time period.
This paper considers the issue of spreading code allocation and receiver optimization in a CDMA-based multiuser data network. Assuming that non-linear serial interference cancellation is performed at ...the receiver, the problem of noncooperative SINR maximization with respect to each user's spreading code and uplink receiver is first considered. It is shown that iterative SINR maximization converges in a finite number of steps, and that the equilibrium resulting from noncooperative behavior is also Pareto-optimal. Next, the problem of optimal multiuser detection for a system using the above optimal spreading codes is also considered, and it is shown that, for such a system, maximum likelihood detection entails a computational complexity that is exponential in the ratio between the number of users and the system processing gain, thus providing huge savings with respect to the general case wherein the optimal receiver has a complexity exponential in the number of users. While initially considering a simple frequencyflat synchronous CDMA system, the obtained results are then extended to more general scenarios, such as asynchronous CDMA systems, multipath CDMA channels, and multiuser multiantenna systems. Finally, the issue of non-cooperative power minimization and choice of the spreading code subject to a QoS constraints is also considered, and comparisons with the corresponding cooperative solution are also discussed. Numerical results corroborate the validity of the theoretical analysis, and show that the use of non-linear interference cancellation coupled with waveform adaptation brings remarkable performance gains with respect to linear multiuser receivers.
Background Little is known about the dermoscopic features of keratinocyte skin cancer. Objective We sought to determine the dermoscopic features of facial actinic keratosis (AK), intraepidermal ...carcinoma (IEC), moderately to poorly differentiated invasive squamous cell carcinoma (SCC), and well-differentiated SCC of the keratoacanthoma type. Methods This was a retrospective analysis of dermoscopic images of histopathologically diagnosed keratinocyte skin cancer. Results A total of 243 (70 AK, 71 IEC, 78 SCC, and 24 keratoacanthomas) tumors of the face from 243 patients (mean age: 71.1 years; range: 44-94 years) were analyzed. The majority of patients had a fair skin type, history of melanoma or nonmelanoma skin cancer, and multiple AK. A red pseudonetwork was significantly associated with AK ( P < .001), whereas dotted/glomerular vessels, diffuse yellow opaque scales, and microerosions were significantly more prevalent among IEC ( P < .001). Hairpin vessels, linear-irregular vessels, targetoid hair follicles, white structureless areas, a central mass of keratin, and ulceration were significantly associated with invasive SCC ( P < .001 for all criteria). Similar patterns as in SCC were observed among keratoacanthomas. Limitations The retrospective design of our study and the lack of assessment of sensitivity and specificity of the dermoscopic criteria are limitations. Conclusions Based on our findings we propose a progression model of facial AK developing into IEC and invasive SCC.
CLEAR CELL ODONTOGENIC CARCINOMA: A CASE REPORT SCHUCH, LAUREN FRENZEL; NORONHA, MARIANA SATURNINO DO; ARRUDA, JOSÉ ALCIDES ALMEIDA DE ...
Oral surgery, oral medicine, oral pathology and oral radiology,
September 2020, 2020-09-00, Letnik:
130, Številka:
3
Journal Article
Recenzirano
A 50-year-old woman with a previous diagnosis of ameloblastoma was referred to the School of Dentistry Brazil complaining of a symptomatic lesion in the body and ramus mandibular. Her medical history ...was unremarkable. The intraoral examination demonstrated an exophytic tumor mass in the right posterior alveolar ridge. Computed tomography revealed a lesion with irregular margins extending from first premolar to distal to second molar of the left side of the mandible. A provisional diagnosis of recurrent ameloblastoma was considered, and an incisional biopsy was performed. Histopathologic evaluation of the specimen showed nests, follicles, and cords of epithelial clear cells. In occasional follicles the central cells showed a reticulum-like pattern, and some central cells showed keratinization. Peripheral cells presented palisading and reverse nuclear polarity. Necrosis, cellular, and nuclear pleomorphism were also observed. Final diagnosis of clear cell odontogenic carcinoma was established. The patient was referred for treatment and is being followed up.
Pleural empyema of extra pulmonary origin is uncommon and empyema secondary to a fistula between the urinary tract and thorax is extremely rare. We report a case of nephropleural fistula causing ...massive pleural empyema in a 64-year-old woman with a long history of urological problems, including nephrolitiasis and urinary tract infection. She was admitted with sepsis, fever, chills, tachypnea, productive cough and pyuria. At clinical examination, breath sounds were reduced over the left hemithorax. CT revealed a fistulous connection from the upper left calyceal group and the pleural space. Drainage of thoracic and perinephric collection was carried out, but nephrectomy and pleural decortication were required due to haemopurulent urine and decreased hemoglobin levels during the hospitalization. This case demonstrates the unusual and prolonged evolution of an obstructive hydroureteronephrosis complicated by pyonephrosis, culminating in retroperitoneal abscess that fistulized into the pleural space, leading to empyema.
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