spherical mass
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Author(s):  
Rachna Dhingra ◽  
Gurbax Singh ◽  
Kuldeep Kumar ◽  
Vignesh A. K. ◽  
Pavail Singh ◽  
...  

<p class="abstract">Lingual thyroid is defined as an ectopic thyroid gland tissue located in the midline of the tongue base. Patients with lingual thyroid tissue usually present with symptoms such as dysphagia, choking, haemorrhage, dyspnea and occasionally life threatening airway obstruction. Lingual thyroid is a rare anomaly with an incidence of 1 in 3000 of the thyroid cases seen, with overall prevalence of 1 in 100,000. Here we presented a case with complaint of difficulty in swallowing and foreign body sensation throat. The intraoral examination showed spherical mass with 2 cm of diameter, covered with intact mucosa, located midline at base of tongue. She was diagnosed clinically as lingual thyroid and evaluated further. By proper transdisciplinary approach correct diagnosis can be made and patient can be managed. In present case, thyroid profile, USG neck and thyroid scintigraphy helped in diagnosis. Patient was managed medically with tablet levothyroxine which relieved her symptoms. Surgical management was not considered as patient improved with levothyroxine and surgical excision would have made patient further hypothyroid as there was no thyroid gland in neck.</p>


2021 ◽  
Vol 2090 (1) ◽  
pp. 012161
Author(s):  
F S Bortoli ◽  
R N Duarte ◽  
R C Souza ◽  
N S Magalhaes ◽  
C Frajuca ◽  
...  

Abstract The resonant-mass gravitational wave detector SCHENBERG is a spherical detector that operates with a central frequency close to 3200 Hz and a bandwidth around 200 Hz. It has a spherical mass that works as an antenna whose weight is 1150 kg and is connected to the outer environment by a suspension system designed to attenuate local noise due to seism as well as other sources; the sphere is suspended by its center of mass. When a gravitational wave passes by the detector, the antenna is expected to vibrate. This motion should be monitored by six parametric microwave transducers whose output signals will be digitally analyzed. In order to determine the detector performance better, it is necessary to obtain the vibration frequencies of the sphere with a better precision. To achieve such a goal the sphere with the holes to mount the transducers and the central hole from which the sphere is suspended is simulated in a finite element method program when the gravity is applied to the sphere and the deformation is kept. After that the vibration normal modes of the sphere are calculated and they are compared to the experimental results.


2021 ◽  
Vol 24 (5) ◽  
pp. E860-E862
Author(s):  
Xianfeng Cheng ◽  
Dawei Shen ◽  
Jie Zhang ◽  
Tao Zhang

Aortic valve myxoma is a rare benign cardiac neoplasm. The association of aortic valve myxoma with cardiogenic shock and acute myocardial infarction has been reported in few observations. We report the case of a 19-year-old male patient, who underwent chest pain for two weeks, then further examinations indicated a soft spherical mass on the left coronary cusp. The patient had sporadic cardiogenic shock and acute myocardial infarction during the preoperative preparation, and we carried out emergency effective cardiopulmonary resuscitation (CPR), followed by emergency surgical operation for aortic valve tumor. Postoperative pathology showed it was a myxoma. The patient recovered smoothly and was discharged on postoperative day 7. Cardiogenic shock and acute myocardial infarction are very nonspecific, and we should be aware that patients with cardiogenic shock and acute myocardial infarction possibly suffer from aortic valve myxoma.


Golden metric tensors exterior to hypothetical distribution of mass whose field varies with time and radial distance have been used to construct the coefficient of affine connections that invariably was used to obtained the Einstein’s equations of motion for test particles of non-zero rest masses. The expression for the variation of time on a clock moving in this gravitational field was derived using the time equation of motion. The test particles in this field under the condition of pure polar motion have an inverse square dependence velocity which depends on radial distance. Our result indicates that despite using the golden metric tensor, the inverse square dependence of the velocity on radial distance has not been changed.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jingjing Wang ◽  
Jing Li ◽  
Xiao Zhang ◽  
Xiaobo Zhang ◽  
Yueyong Xiao

Abstract Background The primitive neuroectodermal tumors (PNETs) are a family of highly malignant tumors with a multidirectional differential potential. The tumors are characterized by aggressive small round tumor cells that originate from the spinal cord of the central and sympathetic nervous systems. Cases involving the pericardium are extremely rare. Herein, we present a case of peripheral primitive neuroectodermal tumor (pPNET) that originated in the pericardium. Case presentation A 23-year-old woman presented with cough and progressive dyspnea for 1 month, followed by eyelid and facial edema for 10 days, without any apparent cause. Significantly elevated tumor markers were detected in her blood. A cardiac ultrasound revealed a 74 mm × 61 mm spherical mass that was attached to the left pericardium, as well as massive pericardial effusion. Positron emission tomography-CT (PET-CT) showed focal hypermetabolism in the left pericardium. Via histopathology and immunohistochemistry, the spherical mass was identified as PNETS. The patient was successfully treated with a combination of surgical resection via thoracotomy and postoperative chemotherapy, and she was disease-free for 7 years at follow-up. Unfortunately, at 7 years after the treatment, the patient’s pPNET recurred. Positron emission tomography-MRI (PET-MRI) and 64-slice coronary CTA revealed that the aorta and multiple coronary arteries were involved. Subsequently, the patient refused a heart transplant and voluntarily left the hospital. Conclusions This paper reports on a rare and recurrent case of PNET in the parietal pericardium. With respect to the different biologic characteristics and prognoses of pPNETs (compared to other known pericardium tumors), it is essential to consider this entity as a differential diagnosis in pericardium tumors.


2021 ◽  
Author(s):  
Charles McGruder

Abstract The Schwarzschild and Kerr metrics are solutions of Einstein field equations of general relativity representing the gravitational fields of a non-rotating spherical mass and a rotating black hole respectively. Unlike the Kerr field, the gravitational redshift in the Schwarzschild field is well known. We employ the concept of stationary clocks to derive the gravitational redshift in the Kerr field demonstrating that frame dragging plays no role. We then calculate the Kerr gravitational redshift for the earth, sun, white dwarfs and neutron stars and compare them with the Schwarzschild gravitational redshift, showing that the gravitational redshift on earth and from the sun does not differ from the Schwarzschild gravitational redshift. For extreme cases of rapidly rotating white dwarfs and neutron stars there is a significant difference between the two gravitational redshifts. Unlike the Schwarzschild gravitational redshift, the Kerr gravitational redshift has to date not been put on a firm observational basis. We point out that the gravitational redshift in the Kerr field possess a latitude dependency, which cannot be confirmed through solar or terrestrial observations, but can be on rapidly rotating white dwarfs and neutron stars


Author(s):  
G.V. Gorr

The problem of the motion of a gyrostat with a fixed point and a variable gyrostatic moment under the action of gravity force is considered. A new method for integrating the equations of motion of a system consisting of a carrier body and three rotors that rotate around the main axes is proposed. The method can be attributed to the method of variation of the constant in the function for the gyrostatic moment, which linearly depends on the vector of vertical. In case of a constant multiplier, the gyrostatic moment satisfies the Poisson equation, and its variation is found from the integral of areas. The original equations have been reduced to a fifth-order system. New solutions of these equations are obtained in the case of a spherical mass distribution for the gyrostat and for the precessional motions of a carrier body. An explicit form of the gyrostatic moment is established for the case of three invariant relations.


2021 ◽  
Vol 16 (3) ◽  
Author(s):  
Monika Sati ◽  
K.C. Petwal

In the present manuscript, we endeavour to review and develop the black hole solutions in general relativity. We emphasize here the Schwarzschild solution in Einstein’s field equation, which describes the gravitational field outside a spherical mass. The paper aims to obtain certain results, including the description of the Einstein field equation with stationary and static solutions and components of the metric that turns out to be time independent, some experiments on the Schwarzschild - Penrose diagram, the Kerr-Newman solution for rotating black holes, and the Reissner- Nordstrom solution for static and charged black holes.


2020 ◽  
Vol 500 (4) ◽  
pp. 5436-5452
Author(s):  
M A Price ◽  
J D McEwen ◽  
L Pratley ◽  
T D Kitching

ABSTRACT To date weak gravitational lensing surveys have typically been restricted to small fields of view, such that the flat-sky approximation has been sufficiently satisfied. However, with Stage IV surveys (e.g. LSST and Euclid) imminent, extending mass-mapping techniques to the sphere is a fundamental necessity. As such, we extend the sparse hierarchical Bayesian mass-mapping formalism presented in previous work to the spherical sky. For the first time, this allows us to construct maximum a posteriori spherical weak lensing dark-matter mass-maps, with principled Bayesian uncertainties, without imposing or assuming Gaussianty. We solve the spherical mass-mapping inverse problem in the analysis setting adopting a sparsity promoting Laplace-type wavelet prior, though this theoretical framework supports all log-concave posteriors. Our spherical mass-mapping formalism facilitates principled statistical interpretation of reconstructions. We apply our framework to convergence reconstruction on high resolution N-body simulations with pseudo-Euclid masking, polluted with a variety of realistic noise levels, and show a significant increase in reconstruction fidelity compared to standard approaches. Furthermore, we perform the largest joint reconstruction to date of the majority of publicly available shear observational data sets (combining DESY1, KiDS450, and CFHTLens) and find that our formalism recovers a convergence map with significantly enhanced small-scale detail. Within our Bayesian framework we validate, in a statistically rigorous manner, the community’s intuition regarding the need to smooth spherical Kaiser-Squires estimates to provide physically meaningful convergence maps. Such approaches cannot reveal the small-scale physical structures that we recover within our framework.


2020 ◽  
Vol 7 (2) ◽  
pp. 16-19
Author(s):  
Lucas W L ◽  
Joseph I K ◽  
Chifu E Ndikilar ◽  
Yakubu N

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