The reproduction of magnetic signatures is an important issue concerning the safety of ship traffic, as well as the identification and classification of vessels. Moreover, military applications of magnetic signatures and their reproduction refer to the activation or protection against activation of magnetic naval mines. Previous works on this subject focused on recording and replicating the signatures under the same conditions as those under which they were measured, e.g., on the same ship courses. In this article, much greater capabilities of the multi-dipole model are presented, including simultaneous identification of permanent and induced magnetism. Determining the dipole values using the data from cardinal directions gives the possibility of determining the magnetic field density at any trajectory (position), direction, or depth, with further reconstruction of the entire magnetic field on the basis of residual measurements. For the purpose of this article, a numerical test model of a corvette-type ship has been modelled in Opera simulation software for different geographical positions. The synthetic data from the simulator served as the data source for determining the parameters of the multi-dipole model and the reference data for the verification of the signatures reconstructed for other positions, directions, and depths than those used to determine the model parameters. To determine all permanent magnetization components, data sets were used for two different values of the external magnetic field vertical component. Finally, as a culmination of the demonstration of model universality, the entire magnetic field around the ship was reproduced for different control points on Earth, and for different courses and depths. Investigating the possibility of reconstructing the magnetic signature at a different geographic location than the place where the measurement was made for model synthesis is the main original issue considered in this paper. The authors of3 presented the system which uses a bottom looking sonar, a Real-time Tracking Gradiometer (RTG), and an Electro-Optic Imager (EOI). The above problem is serious and dangerous for all ferromagnetic ships. The main sources of the ship’s magnetic signature were described in5. There are several analytical models of the magnetic field generated by a sphere7 and a prolate ellipsoid8. The spheroidal harmonic expansion coefficients of the magnetic scalar potential have been applied in the mathematical model of a prolate spheroidal marine vessel11. The authors of these articles discussed several strategies to improve the estimation of model parameters based on the measured field data. They achieved a series expansion which describes the ship’s signature in its near field very accurately. When sufficient information is provided by near field measurements, then the far field can also be accurately represented. The disadvantage of that model is that it reproduces the signature only along the lines for which the measurements have been carried out. Modelling of the magnetic field of a given ship is complicated due to its shape and magnetic properties of ship’s steel. The ship constructed of ferromagnetic steel has two types of magnetization: induced12 and permanent. The ship's magnetic field can be modelled using a set of induced and permanent dipoles and then calculated using the FEM method15. In16, the ship’s multi-dipole model was compared with the physical model in North–South and South–North direction with good results. In17, the authors presented a multi-dipole magnetic model of the ship using the induced and permanent magnetic dipoles, and compared it with a real warship with good results. The authors of19 presented a multi-dipole model which allows to reproduce the ship’s magnetic signature for any direction and depth. That model was also compared with success with the real marine ship Zodiak20. The magnetic signature can be decomposed into parts referring to induced and permanent magnetization22. In21, the authors introduced an algorithm for this signature decomposition. The applied method was based on measuring the magnetic field in four cardinal magnetic directions of the ship: 0°, 90°, 180°, 270°. The permanent magnetization can be assumed independent on the external field, while the induced magnetization depends on the strength and direction of the Earth’s magnetic field. After introducing the effective permanent dipole moment by adding the induced vertical dipole moment to the permanent vertical dipole moment, the authors of21 solved an inverse problem and presented the ship’s magnetic signature for another direction in the same area.A ship constructed of ferromagnetic steel disturbs the Earth’s magnetic field. This disturbance is called the ship’s magnetic signature and due to it the ship can be destroyed by marine minesthe magnetic signatures can be reconstructed for an arbitrary direction of the ship,the magnetic signatures can be reconstructed for an arbitrary water depth, but greater than the measuring depth Important properties of the multi-dipole magnetic model which were recognized during the previous research performed by the authors of this article are:The ability to determine the level of magnetic field density at different depths and for different directions is a very important feature of the multi-dipole model. This property is also used to validate the model. When the values determined from the model (with parameters from a different geographic location and depth) coincide with the values determined from the reference source (measurement or FEM), the validity of the model can be confirmed.z- constant). In this article, the authors extend the analysis of the functionality of the multi-dipole model to include the potentially extremely useful feature of transferring a magnetic signature acquired in one geographic location to another. The analysis undertaken in this article is an original contribution to establishing the conditions under which signature transformation is possible. On the basis of the magnetic fields generated by the numerical model of a ship built in Opera 3D for six different points on Earth’s surface , the authors investigate the possibility to reconstruct the magnetic signatures. The simulations of ship’s magnetic fields were carried out in Simulia Opera 3D23 using the thin plate boundary condition24. Material isotropy of the ship was assumed in the numerical simulations. The knowledge about the ship’s magnetic signature at an arbitrary point can be used to design a degaussing system which would minimize the magnetic signature30.This virtual magnetic model reconstructs the ship’s magnetic field very well not only along specific lines but also at any point of the surface   by the n-th dipole with coordinates , the magnetic moments of the induced and permanent dipoles were calculated for the ship located in the region with the Earth's magnetic flux density vector components (Ez) Fig. . The magn-th dipole, and x, y, z) from the n-th dipole position with coordinates , i ∈  < 1, Np > , j ∈  < 1, Ni > , n ∈  < 1, Np + Ni > , where Np is the number of dipoles.The multi-dipole model distinguishes between permanent and induced dipoles. The parameters of all dipoles are calculated for ship’s course  formula  and form formula , respectThe total magnetic moment vector is:BEx, 0, BEz)  can be calculated as:The value of the Earth’s magnetic field is weak  and therefore changes of the magnetic field inside the ship steel remain on the linear part of the magnetization characteristic. The components of the induced magnetic moment of the dipole depend proportionally on the Earth’s magnetic field (Ez) Fig. . Thanks BE′. The permanent magnetic moments of the dipoles do not depend on the external field and direction. That makes it possible to reconstruct the ship’s magnetic signature at any point on Earth by scaling only the induced dipoles.Equations –10 allow24. The degree of magnetization of the ferromagnetic plates of the ship’s hull is unknown. The phenomenon of permanent magnetization of the ship’s steel is complex and the magnetization itself is constantly and slowly changing due to mechanical impacts of the ship against the water surface or against the quay. In this paper, coils inside the ship are used to simulate the permanent magnetization of the steel. A series of coils as shown in Fig. μr = 200 and thickness 1 cm of the ferromagnetic steel were assumed. This value is one of the typical values of ship steels. However, the effect of the relative magnetic permeability of steel on the magnetic signature is significant. The great advantage of the multi-dipole model is the selection of model parameters based only on synthetic or real magnetic data without the required ship shape and relative magnetic permeability values. For the purpose of verifying the proposed method of reconstructing the ship's magnetic signatures, an equal value of relative magnetic permeability of steel was assumed in the simulation.The numerical model of the ship was built in the Opera 3D program. This program, using the FEM method, has a very useful property for modelling of objects with relatively small thickness of ferromagnetic material. The thin plate boundary condition implemented in this program allows FEM-based modeling of ships with good shapesThe magnetic fields of the ship’s model at different points on Earth were calculated by introducing appropriate values of the external field. After subtracting the total magnetic field from the Earth's field, the ship’s magnetic signature at any point on Earth was obtained. The values of FEM parameters are given in Table Bx, By, Bz. The largest MFD values are present under the keel, but in order to correctly reconstruct the signature for a ship with both induced and permanent magnetism additionally, field values at the sides of the ship are usually measured as well. Such diverse origins of the data describing the field make it possible to obtain a robust model. The fields are crossed at PKS  lines—see Fig. 27.The data for a single scenario calculation refers to four cardinal directions  and fields with dimensions of 601 × 601 points  for all MFD components 18 and19. For the convenience of the reader, the optimization criterion is presented here as . Inside the criterion function, there is the sum of squares of model and source data differences for individual magnetic field components.The objective function J (11) defines the difference in matching the reference and model data in all considered directions, for paths P, K, S (9), over the length of 600 m, with the resolution of one meter for magnetic field components Proper determination of the parameters of the multi-dipole model requires acquiring data in the four magnetic directions 0°, 90°, 180° and 270°. For the ship's 0° and 180° courses, it is possible to obtain information on the ship's longitudinal magnetization, and for the 90° and 270° directions on transverse magnetization (30). Determining the dipole model parameters associated with vertical magnetization is more complex, as it requires obtaining the ship's magnetic data for two different vertical components of the external magnetic field (30). If the ship had only induced magnetization, then data obtained only under the keel would suffice. However, in practice, every ship has a permanent magnetization, so the minimum data needed to reconstruct the signature requires acquiring data under the keel and from the starboard and port sides.28 method, available in computing packages, has been tested for this purpose in many applications.Gradient and non-gradient methods can be used to solve this nonlinear optimization task. However, the latter require significantly longer computation time, hence the gradient approach is used in practice. The Trust Region Reflectivex, y, z space of the multi-dipole model. The space for the dipoles is assumed to be a cuboid described on the ship in the space limited by the ship's body as shown in Fig. 27.The solution to the optimization task has a form of six values for each of the induced and permanent dipoles. The first three parameters refer to the magnetic moment components, while the next three are the locations of the dipoles in the The correctness of the new approach to the reconstruction of ship’s magnetic signatures at any point on Earth was verified for cases without and with permanent ship’s magnetization. Three simulation scenarios S1, S2, and S3 were investigated, as shown in Table 28. Next, all induced magnetic moments of the dipoles were scaled according to formulas  were first achieved using the optimization methodformulas –9 for eaformulas  and inclformulas  of the EThe results of particular simulation scenarios can be compared qualitatively in the form of graph observations, and quantitatively using the RMSE (root mean square error) and MaxAbsError indicator values on the paths. The indicator RMSE provides the information about the average result, while MaxAbsError represents the maximum error along the considered path. Taken together, these indices make it possible to evaluate the signature reconstruction.The root mean square error is given by:modeli is the vector of N signature values at i-th position coordinate counted by the model, and refi is the vector of N reference signature values at the same position.and the MaxAbsError is given by:z = − 20 m) are available, for all cases, at27. Figure The ship’s magnetic signatures without permanent magnetization were calculated in Opera. The parameters of the multi-dipole model for each point V1 ÷ V6 were obtained from the data for four ship courses. After scaling the induced moments of the multi-dipole model, the magnetic signatures were compared at all points with those obtained from Opera. The magnetic signatures calculated in four directions under the ship keel  cells represent the scenarios considered unsuccessful.27. The RMSE and MaxAbsError indicators for all cases are given in Tables A more complicated, but also more practical problem concerns permanent magnetization of the ship. The magnetic signatures for four directions and for all points V1 ÷ V6 are available at27. The RMS and MaxAbsError indicators for all cases are given in Tables As shown in Chapter 4.2, the vertical components of the permanent magnetization dipoles cannot be correctly designated when the magnetic data is acquired with only one value of the constant vertical component of the external field. A correct approach in this case is to acquire the magnetic data in four magnetic directions for two different values of this component. Therefore, in addition to the data about the vertical component of the Earth’s magnetic field already collected at a given geographical location in four magnetic directions, additional data must be acquired for a different value of this component. Change in the value of the vertical component of the Earth's magnetic field can be executed by using a system of constant current coils generating a uniform vertical magnetic field around the vessel. In all cases presented in this Chapter, the magnetic data was added for the vertical component of the Earth field intensity changed by 20 A/m. The magnetic signatures for all cases are available atThe magnetic signatures at point V5 reconstructed based on the scaled model obtained at point V2 are shown in Fig. The multi-dipole model has the ability to reconstruct magnetic signatures for an arbitrary measurement direction and depth, not only for the directions and depths that were used when teaching the model, i.e., determining dipole parameters. Combining the ability, described in the article, to reconstruct the signature in a different geographic location than that in which the dipole parameters were determined with the ability to use an arbitrarily chosen depth and direction, a set of universal functions of the multi-dipole model is obtained. To illustrate the described properties, additional data sets were generated by the FEM with already known positions, but for other depths and directions of ship’s position. Details are shown in Table In this simulation calculation, the values of the dipole parameters determined for Scenario 3 (BZ_off) were used. In addition to these dipoles, the direction and depth parameters from Table A new universal approach to the reconstruction of ship’s magnetic signatures is described in the article. In this approach, the magnetic signatures of the ship are first acquired on the measuring range in four magnetic directions. After subtraction from the Earth magnetic field, the measured three components of the total magnetic field give the own magnetic field of the ship. Based on the measurements taken, the ship’s magnetic field can be replaced by the magnetic field of the virtual multi-dipole model, which allows to reconstruct the ship magnetic field for any course and for depths larger than the measuring depth. With the use of two different values of the vertical component of the external magnetic field, the values of the ship’s magnetic field vector components measured in four magnetic directions allow the parameters of the induced and permanent dipoles to be correctly determined. Once the induced dipoles of the multi-dipole model are appropriately rescaled, it is possible to accurately reconstruct the magnetic signatures of a ship situated anywhere on Earth. This method requires an arrangement of special coils with constant current to change the vertical component of the earth's magnetic field.The measurements of the ship’s magnetic field should not be made at the magnetic poles, because in these places it is difficult to reproduce the parameters of the multi-dipole model without a special coil system changing the horizontal components of the Earth magnetic field. Verification studies were conducted with synthetic data based on locations at various points on Earth. With the exception of points with features completely devoid of a horizontal component (magnetic poles), at all other points it was possible to successfully determine the dipole parameters and then use them to reconstruct the signature at any geographic position, ship course, and depth lower than the measuring depth. Thus, the versatility of the multi-dipole model has been confirmed through numerical experiments. It would be very fruitful to confront the obtained results with real field measurements.27. Any researcher can use the source data to verify the research results presented in the article and to search for new optimization algorithms in determining the parameters of the multi-dipole model. The dataset contains source synthetic magnetic data for a numerical model of a corvette-type ship. The data are provided for 6 locations around the world with different values of the Earth's magnetic field V1 ÷ V6. The attached data are in Matlab format. MAT, but the data can also be used in Octave software.An archive with a set of input and verification data is shared by the authors for further analysis


Basal cell carcinoma and squamous cell carcinoma are malignant epithelial tumors that frequently occur on the scalp. The reconstruction of large surgical breaches in which the scalp was removed leaving the bone bare has always been a difficult problem to solve.An 84-year-old patient in good general condition with an extensive surgical breach in the scalp comes to our observation where a sessile squamous cell carcinoma was removed 2 months ago in another hospital; The surgeon had removed the aponeurotic galea with bone exposure.There are numerous surgical solutions proposed: reconstruction by a secondary intention, grafts of dermal matrix, transposition flaps and finally an old technique that involves the perforation of the cranial theca. Dermal matrices cannot be used on bone as they still need blood support to facilitate the repair process. Local flaps could not be used as the skin was seriously photodamaged and treatment of this would further delay the repair. In our case the solutions adopted with other patients were not applicable, therefore we evaluated the literature to determine which solution could be adopted. We had experience with tissue perforation in large ulcers and position punch grafting to facilitate re-epithelialization therefore we also drew inspiration from this method.The technique adopted allowed an immediate reconstruction limiting the discomfort to the patient with few dressings and complete healing in about 1 month. Scalp, the graft is completely rooted in 3 month. •Large surgical breaches in the scalp removed leaving the bone bare have been a problem to solve.•Dermal matrices facilitate the engraftment of full-thickness grafts.•It is important that surgical procedures limit patient discomfort in the weeks following surgery. All services and hospitalization were taken care of by the National Health Service.Patient operated on in early September 2021 in another hospital for infiltrative squamous cell carcinoma of the scalp.The surgical beak with exposed bone was left open and after numerous unsuccessful medications, the patient came to our clinic at the end of October.After 3 days we admit him to the medical department to treat the injury with Vac therapy and prepare him for surgery which is performed after 5 days. The post-surgical hospital course was 1 week .Subsequently, the patient was treated in one of our outpatient services until he recovered completely.2An 84-year-old patient in good general condition with an extensive surgical breach in the scalp comes to our observation where a sessile squamous cell carcinoma was removed 2 months ago in another hospital; The surgeon had removed the aponeurotic galea with bone exposure.no significant improvements for two months, so much so that the patient turned to our department.The numerous dressings that had been done had achieved to The surrounding part of skin had significant photo damage with actinic lesions, some of which were evolving epitheliomatous.Histology had confirmed a squamous cell carcinoma of the skin NAS .Histologic examination revealed a moderately differentiated (G2) deeply invasive squamous cell carcinoma NOS with infiltrative margins and a tumour thickness >6 mm, without evidence of vascular and perineural invasion, in a background of actinic keratosis; the tumour infiltrated the underlying galea up to the edge of the inked margin. The maximum diameter of the tumour was 55 mm .The wound of about 7 cm in diameter was covered with purulent discharge .Fig. 1ExThe patient is hospitalized for intravenous antibiotic therapy and a wound dressing is performed every day with a non-alcoholic disinfectant solution. After removing the necrotic tissue and purulent secretion, it shows the initial suffering of the external cranial table.After 3 days of antibiotic coverage, an intermittent vacuum therapy at 80 mm hg is placed for one week to clean all the external skull table and stimulating granulation tissue at the periphery of the surgical wound.The granulation tissue is present only in some minute areas mainly in the periphery.The procedure was proposed by the dermosurgeon, author of this article, and shared with the anesthetist and neurosurgeon .The surgery is performed under general anesthesia. The surgical team is made up of a neurosurgeon and 2 dermal surgeons. The surgical time from the beginning of the cut to closure was 1 h and 10 min. An intraoperative antibiotic coverage was made with 2 g. of intravenous cefazolin and a post-surgical antibiotic coverage with 1 g of ampicillin and clavulanic acid every 8 h for 10 days.Approximately 15 holes of 4–5 mm in diameter are drilled using a high-speed cutting bur and subsequently a curettage to bloody the diploe to facilitate bleeding .Fig. 2a)The holes were drilled taking care not to injure the dura. The perforation was stopped when bleeding from the diploic spaces occurred.A dermal matrix Type 1 heterologous equine collagen and hyaluronic acid in sterile sponge plates 10 × 10 cm adaptable to the site, thickness about 2 mm is placed on bone tissue with bleeding breccias.The graft divided into 2 fragments removed from the thigh, degreased and thinned, positioned in the breach and fixed with staples and resorbable 3/0 surgical threads. The graft is fenestrated and medicated with greasy gauze and a moderate compression dressing .Fig. 3ThBleeding was limited and controlled with diathermocoagulation, it was not necessary to proceed with blood transfusions.The dressing is removed after 8 days and the stitches after 12 days.The patient was checked every week for the first month then every 2 weeks for 3 months.The graft is completely rooted .Fig. 4ScThe work has been reported in line with the SCARE criteria.3The reconstruction of the scalp, with the exposure of the bone, has always been a difficult problem to solve. There are numerous surgical solutions proposed: reconstruction by a secondary intention , grafts Secondary intention reconstruction takes a very long time and creates considerable inconvenience to the patient.The use of dermal matrices is similar to the previous solution with perhaps shorter times .Thin grafts are only a temporary solution and in any case it is necessary to create a blood supply condition.The milling of the cortical theca reduces the solidity of the theca itself, therefore we have identified in this old method a good solution with the variant of inserting a dermal matrix to immediately rebuild with a medium thickness graft .The presence of a tissue surrounding the surgical breach with numerous actinic lesions, some of which are in epitheliomatous evolution, excluded the possibility of practising transposition in the flap from neighburing areas with grafting in the site of donation of the flap.In the history of plastic surgery we find references of this technique dating back to the 18th century. The earliest reference we have found of this technique came from a study by Mellish  in 1904 In 1914 Flaherty  describeOver time, rotational flaps and microvascular flaps have become the gold standard for reconstruction of surgical breccias with an exposed skull table. Their main advantage was the lack of waiting time for wound granulation and the elimination of the need for repeated dressings.Furlanetti et al.  MentioneCalderoni et al.  also staIt was not easy to find a solution that would lead to a quick resolution of the problem that had been going on for months.Dermal matrices cannot be used on bone as they still need blood support to facilitate the repair process. Local flaps could not be used as the skin was seriously photodamaged and treatment of this would further delay the repair. In our case the solutions adopted with other patients were not applicable, therefore we evaluated the literature to determine which solution could be adopted. We had experience with tissue perforation in large ulcers and position punch grafting to facilitate re-epithelialization therefore we also drew inspiration from this method.Certainly the infectious risk in a technique such as the one adopted is possible. We must consider that the wound arrived covered in purulent material and that the brief pre-surgical treatment healed it.4The technique adopted allowed an immediate reconstruction limiting the discomfort to the patient with few dressings and complete healing in about 1 month. Scalp, the graft is completely rooted in 3 months. Control visit at 6 months .Minimally invasive surgery with reduced surgical times that does not identify significant contraindications other than those related to general anesthesia , Fig. 7.The patient was managed in a public hospital, a provincial reference center of the Piedmontese oncological network for skin cancer. All services and hospitalization were taken care of by the National Health Service.Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.Access to the ethics committee and its authorizations are not applicable in our case because the individual surgical and therapeutic techniques are consolidated and do not represent a study.No any sources of funding for your research.Each author contributed study concept and design, data collection, data analysis or interpretation, writing the paper.Mauro Carducci, MD.The ethics committee clearance was not necessary for e standard surgical treatment. Not applicable in our case because the individual surgical and therapeutic techniques used, are consolidated and do not represent a study of research.All the authors declare that they have no conflicts of interest.


We study the effects of rotations on a cold atom accelerometer onboard a Nadir pointing satellite. A simulation of the satellite attitude combined with a calculation of the phase of the cold atom interferometer allow us to evaluate the noise and bias induced by rotations. In particular, we evaluate the effects associated to the active compensation of the rotation due to Nadir pointing. This study was realized in the context of the preliminary study phase of the CARIOQA Quantum Pathfinder Mission. Their sensitivity and accuracy are expected to increase dramatically in microgravity, where the interrogation time is no longer limited by the size of the instrument3. This triggered a recent interest in developing this technology for space6 with potential applications in geodesy11, fundamental physics13, navigation and gravitational wave observation15. Opening the way to those developments, the CARIOQA Pathfinder Mission16 aims at realizing the first quantum accelerometer on a satellite. This space mission will consist in a single axis cold atom accelerometer designed to measure the non-gravitational acceleration along the velocity direction of a satellite on low Earth orbit. The mission is meant to realize key milestones for space atom interferometry and demonstrate unprecedented performances for quantum accelerometers.Quantum inertial sensors based on cold atom interferometry have reached a level of performances and maturity allowing for scientific and commercial use in various ground based applications17 that this rotation must be compensated to avoid a dramatic loss of contrast due to inhomogeneous Coriolis effect. In this article, we study the impact of rotation on the sensitivity and accuracy of the future CARIOQA cold atom accelerometer. We evaluate the phase of a rotating atom interferometer, with and without compensation, and identify a systematic effect related to rotation compensation. This systematic effect is then demonstrated experimentally. We realize a simulation of the attitude of a low orbit satellite to obtain angular velocity time series and we use those time series to estimate the noise associated to residual rotation fluctuations and to the rotation compensation system.Adapting cold atom accelerometers to low orbit environment requires to take into account residual fluctuating rotation of the satellite due to atmospheric and solar winds. Besides, various future missions (including CARIOQA) will require to operate in a Nadir pointing orbit, which implies a constant angular velocity in the mrad/s range. It has been identified20 embarked in a Nadir pointing satellite. The interferometer’s measurement axis is aligned with the velocity vector axis (x-axis). A mirror (M) used to retro-reflect the interferometer laser beams is rigidly fixed to the case of the satellite and constitutes the reference against which the acceleration of the free falling atom cloud (A) is measured. In this configuration, the instrument measures the non gravitational acceleration of the satellite along the x-axis. All positions are defined relative to the center of mass of the satellite O which is taken as the origin of a reference frame aligned with the satellite main axes  = (Ωx(t), Ωy(t), Ωz(t)) on O . The configuration considered is a three pulses Raman interferometer with double diffraction21. The total output phase difference can be expressed as a sum of the laser interaction phases during the interferometer:We evaluate the output phase of the interferometer in the presence of an acceleration along keff is defined by the orientation of the retroreflection mirror M. When the mirror is fixed in the satellite frame, keff is constant and we can write:rA(t) (resp. rB(t)) is the classical position of the atomic wave packet on the path A (respectively B) of the interferometer at time t.The effective laser wave vector a is the linear acceleration of the atoms relative to the satellite case, which corresponds to the non-gravitational acceleration of the satellite, and m is the atomic mass.We evaluate the classical trajectory of the atoms in the non Galilean satellite reference frame by solving the equations of motion using a polynomial ansatz with the Lagrangian:T:r0 =  is the initial position of the atoms and  their initial velocity in the satellite frame and Gx =  is the gradient of the component along x of the Earth’s gravity. Here Ω =  is the temporal mean of the time dependant angular velocity during the interferometer. Besides acceleration along the x-axis, this expression shows that the interferometer is sensitive to Coriolis (term 5) and centrifugal accelerations (term 6). In the context considered in this article, rotation rates are always smaller or on the order of 10−3 rad/s. As a consequence, the higher order terms are at least 3 orders of magnitude smaller than the terms in the above equation and will be ignored. For example, third order terms corresponding to the interplay between the gravity gradient and rotations (i.e. TΩyGxxz0) are on the order on 10−15 m s−2.Atomic wave packet positions are evaluated at each pulse and inserted in equation . We obtaN ≃ 1 mrad/s around the y-axis. Given the initial velocity spread of the atoms, Coriolis acceleration is expected to induce a phase inhomogeneity across the cloud and limit the instrument17. Even at a temperature as low as Te ≃ 100 pK, the interferometer contrast would drop drastically for interrogation times T larger than 1 s. The commonly accepted solution is to compensate the Nadir rotation by counter-rotating the retro-reflection mirror at the same rate during the interferometer23. The effective wave vector keff has then a fixed direction in the inertial frame but varies in the satellite frame. In this case equation  as the constant angular velocity of the mirror, and rM =  the position of its center of rotation. We also consider the possibility to rotate the incoming laser beam and define its angular velocity ΩI = . A geometrical calculation of the laser phase at position r =  as a function of the mirror and incoming beam orientation yieldsdM as the distance between the mirror’s reflection plane and its center of rotation M. θM (respectively θI) is the angle between the mirror’s reflection plane (resp. the incoming beam’s equiphase plane) and the z-axis , and for a differential measurement the rotation compensation phase can be expressed as:We observed experimentally this phase term (11) using a ground based cold atom gravity gradiometer. The experimental setup, described inT = 10 ms as a function of the angular velocity. The differential phase at ΩM = 0 was taken as a zero reference point in order to extract the angular velocity dependence only. The measurement is displayed in Fig. δv0 between the two clouds that causes a Coriolis effect Δϕcoriolis/(keffT2) = 2δv0ΩM. The green dashed line shows the result of a fit of the data with the sum of the quadratic and linear term, using δv0 as the only adjustable parameter. We obtain the value δv0 = 1.3 ± 0.11 mm/s. Residual dispersion of the measured phase around the expected value larger than statistical uncertainty can be due to laser phase profile inhomogeneity.Here we use single diffraction Bragg pulses, which explains a phase smaller by a factor of 2 compared to the calculation for double diffraction. In order to probe this result, we performed a differential phase measurement of the two interferometers of duration 17. The CARIOQA interferometer will rely on a delta kick collimated atom source similar to the one described in25, which effective temperature can be lowered to Θ = 4 × 10−11 K. Figure T increases, unless the residual angular velocity remains close to 1 μrad/s. This can be achieved by counter rotating the reference mirror, which implies a real time knowledge of the satellite’s angular velocity during the interferometer sequence to that level of stability, but also a control over the angle of the rotating mirror and incoming beam down to about a few microrad. An alternative or complementary technique, point source interferometry23 with a spatially resolved detection, can also be used to reveal the velocity dependent phase structure in the atomic cloud. However, in this process the quantum projection noise limited sensitivity is reduced by a least a factor The velocity spread of a finite temperature atom cloud induces a phase inhomogeneity that alters the contrast of the interferometerμrad/s, with an angular velocity compensation perfectly aligned around the y-axis, that follows the driven orbital angular velocity from the AOCS.For the following, we consider a rotation compensation with a shot to shot standard deviation of the angular velocity of 1 N = 105 atom, as expected for the CARIOQA instrument. The parameters used for this comparison are given in Table T which is the main variable parameter for the future mission. As the future performances depend strongly on T, we consider different values between 1 s and 5 s.Using the phase expression found in the section “The inhomogeneous Coriolis effect” and the attitude simulation described in the section “Methods”, we estimate the phase noise associated with residual (uncompensated) rotation noise of the satellite and compare it to the expected sensitivity of a quantum projection noise (QPN) limited atom interferometer with 25, we anticipate a delta kick collimated atom source with a residual initial mean velocity v0 of about 100 μm/s.The Centrifugal acceleration noise depends on the initial distance between the atom cloud and the center of mass of the satellite. The control over this value is expected to be limited by the knowledge of the center of mass’s position in the satellite frame, to about 1 mm. The Coriolis acceleration depends on the initial mean velocity of the atom cloud. From26. If we describe the rotation noise source by a power spectral density (PSD) S(f), the resulting RMS phase noise of the atom interferometer is calculated as:H(f) is the atom interferometer transfer function. For this simulation, we also took into account a potential loss of contrast due to the inhomogeneous Coriolis acceleration.The effect of time-dependent perturbations on the atom interferometer is modeled using the formalism of the sensitivity functionFigure M of x0 = OA), for two different distances between the atoms and the mirror (AM). The smallest possible distance for a t = 5 s interrogation time is AM = 6 cm. We also compare between the situation when only the reference mirror is rotated .As shown in the section “Introduction”, the nadir rotation compensation induces a phase shift to the interferometer if the center of rotation of the mirror (M) is not perfectly superimposed to the center of mass (O) of the satellite. A noise associated to this phase can appear because of an imperfect control of the rotating mirror’s angle and limit the sensitivity of the instrument. The usually considered technical solution for rotating the mirror is to use a piezoelectric tip-tilt platform. With this technique M is usually close to the mirror, which implies a distance of a few tens of centimeters between M and the initial position of atoms A. Based on commercially available systems, we anticipate a shot to shot jitter of the mean rotation rate Ωmentclass2pt{minimAM is more favorable. Rotating the incoming beam also allows to improve the sensitivity by a factor two . In the−7 m. s−2 if xM is a few centimeters. Satellite navigation relies on rocket fuel propulsion that may cause a long term drift of the position of the center of mass. Under the conditions considered, the measurement bias associated to mirror rotation is on the order of 10−7 m. s−2 with a variation of 10−9 m. s−2 per millimeter drift of the position of the center of mass. A precise modeling of the center of mass variations may be necessary to evaluate this systematic effect. Alternatively, a calibration of the bias term could be performed by varying the satellite’s total angular velocity.Besides the limitation on the sensitivity of the instrument, its accuracy and long term stability can be also limited by the rotation compensation system. The phase term associated to the rotation of the mirror and of the incoming beam can be as large as a few 10−10 m. s−2. Hz−1/2 in low orbit with a relatively standard attitude control system and state of the art ultra-cold atom technology. This was illustrated by a specific set of parameters, however future design studies may aim at better performances by either improving the AOCS or the cold atom system.In this article we evaluated the effect of rotations on the performances of a cold atom accelerometer in a low orbit Nadir pointing satellite for the future CARIOQA mission. A simulation of the satellite’s attitude along with a calculation of the interferometer’s phase allowed to specify some instrumental parameters such as the initial velocity of the atomic cloud, its positioning in the frame of the satellite and its temperature. We showed that it is possible to maintain the rotation related phase noise limit on the sensitivity of the instrument down to a few 10When the Nadir rotation is compensated, we identified a phase term due to an imperfect alignment between the rotation axis of the mirror and the center of mass of the satellite. This term can limit the sensitivity of the instrument, as well as its accuracy. The rotation compensation system has to be designed in accordance in the frame of the CARIOQA Quantum Pathfinder Mission, as well as in other future space atom interferometry missions.27. We used a 4 Hz gyrostellar attitude determination system28, composed of a star tracker consistent with the HYDRA equipement caracteristics, and a gyrometer consistent with the ASTRIX-NS. It consists in a simplified version of a gyrostellar Kalman filter with a low-pass second order filter on the star tracker measurements and a high-pass second order filter on the gyrometer measurements with the same cut-off frequency (the hybridization frequency). An estimation of the gyrometer default  was also added to the estimator part to improve the angular velocity estimation.We performed a Matlab/Simulink simulation of the future CARIOQA satellite attitude in order to obtain realistic angular velocity time series. Figure μrad/s level. A periodic variation of the commanded angular velocity around y-axis with an amplitude of about 3 μrad/s was added to take into account the orbit eccentricity.The resulting angular velocity time series are presented in Fig. Further information on research design is available in the Reporting Summary


To describe the level of knowledge of undergraduate students in Jordan toward COVID‐19 in children in respect of the clinical signs of the disease, modes of transmission, protection measures against the disease and satisfaction with governmental measures.A cross‐section was utilized in this study.An online survey questionnaire was utilized in this research study. All undergraduate students in Jordan were able to take part. The size of the sample was 799. Knowledge toward COVID‐19 among children was used to assess the participants' knowledge about COVID‐19.The findings indicate that the students had a good understanding of the clinical signs, mode of transmission and protection measures and were satisfied with governmental measures. According to the students' responses, the resource they used the most was social media followed by news channels. Our study also found that medical specialty students had more knowledge toward COVID‐19 than non‐medical. Therefore, this paper focuses on COVID‐19 in children for the following reasons: First, even though there is a low probability of children experiencing severe illness due to contracting COVID‐19 as compared to older adults, various subpopulations of children have an elevated possibility of developing a more severe form of the disease  to lower the incidence of COVID‐19 in the general population and particularly in children. Thus, it is essential to review the knowledge toward COVID‐19 among first, second, third, fourth, fifth and sixth year undergraduate students enrolled in Bachelor of Science (B.Sc.) programs at Jordanian private and public universities. Due to this gap in the literature, the researcher performed this study. Specifically, this study aimed at (a) describing the level of knowledge of undergraduate students in Jordan toward COVID‐19 in children in respect of the clinical signs of the disease, modes of transmission, protection measures against the disease and satisfaction with governmental measures.22.1A cross‐sectional design was employed to collect data from the participants.2.2All undergraduate students from all government and private universities in Jordan were eligible to participate in the study so long as they met the following inclusion criteria: (1) able to read and write in the Arabic language and (2) aged more than 18 years old. Students were excluded if they are not able to write and read the Arabic language. The quota sampling strategy used was based on the participant's age and gender to ensure that the sample was a broad representation of the general population in Jordan. The sample size of the study was calculated using G‐Power 3.1., Universitat Kiel, Germany (RRID:SCR_013726), based on convenience/quota sample method, small effect size, alpha of 0.05 and power of 0.95. The required minimum number of subjects was 750 More than 1000 questionnaires were sent out electronically to undergraduate students from all universities in Jordan. The authors used STROBE checklist to ensure meeting all the requirements for a cross‐sectional study  was used to assess the participants' knowledge about COVID‐19. This instrument was adopted from another study that used the instrument to measure the knowledge of parents about COVID‐19 in children  of Jordan University of Science and Technology (JUST) to conduct the study. Following receipt of IRB permission, the participants were recruited via online advertisement distributed on social media such as Facebook and Twitter. Anyone interested contacted the researchers to let them know they wanted to participate. The researcher sent them the consent form and the survey online via social media such as Facebook, Messenger, WhatsApp and other social media applications for people who sent that they met the inclusion criteria. To avoid bias, the link of the study was mentioned in the cover letter of the electronic survey that people who did not meet the inclusion criteria, and they should not participate in the study. More than 1000 questionnaires were sent to undergraduate students in public and private universities in Jordan.2.5Jordan University of Science and Technology IRB approved this study. The researcher approached eligible participants and issued them with detailed information regarding the objective of the study. This information included the following statements: “The researcher will utilize the information in assisting the community and the university; the researcher will keep the student information private; the researcher will not use any information in presentations or publications in a manner that will result in your [the student's] exposure to the Principal Investigator and the Office for Human Research Protection at (243/2020)”.2.6The Statistical Package for the Social Sciences version 25 was used for all statistical analyses . The results of the descriptive and bivariate analyses were deemed significant based on an alpha level of less than .05. The Kolmogorov–Smirnov test was used to evaluate the normality of all continuous variables. Any discrepant variables were transformed into more distributed scores. The subjects' responses were evaluated for each variable (measure). If each variable had 40% or more missing data, then the participants' responses for that measure were deleted list‐wise (10). Where the amount of missing data was below 40% this imputed from the mean of the responses to the items for each variable. Descriptive statistics were used to describe the research subjects' demographics and the total scores for each of the variables. Outliers were determined and eliminated prior to the data analysis.33.1A total of 1000 questionnaires were distributed, and 799 undergraduates filled in and returned the questionnaire. Therefore, the response rate was 79.9%. Out of the 799 participants, 528 were female (66.3%) and 263 were male (37.3%). The mean age of the participants was 21 years. See Table 3.2n = 520, 65%) followed by news channels . The least used source was other sources such as newspapers . See Table There are many resources from which to gain information regarding COVID‐19. According to the students' responses, the resource they used the most was social media n = 50, 65% fo3.3n = 720, 90.1%) was a clinical sign, followed by cough . Only a few reported that red eyes  constituted a clinical sign. As regards transmission, the three main modes that were recognized by the students were touching surfaces such as door handles and tables , coughing and sneezing , and shaking hands . See Table Information was collected regarding the students' knowledge about the signs and symptoms of COVID‐19 in children. Many correctly stated that fever  and that “Educating people about coronavirus in children is important to prevent the spread of the disease” . However, very few students answered “know how to apply social separation with family children” as an effective way to reduce the incidence of the disease . See Table n = 644, 87%). Also, most students supported the government measures that required that children should stay at home all the time  and that schools suspend their operations .Many measures can be taken to prevent the spread of COVID‐19. Students were asked to choose from multiple options for possible ways to prevent COVID‐19 in children. Almost all the students answered that “Quarantine for all family members (stay at home) to protect children”  to protect children” and “Educating people about COVID‐19 in children is important to prevent the spread of the disease.” On the contrary, only a few students answered that “Applying social separation with family children” is an effective way to combat the disease. Methods of lowering COVID‐19 transmission include personal and environmental actions, determining and separating incidences, tracing contacts and quarantining, implementing measures on social and physical distancing including the banning of mass gatherings, setting rules for international travel (Adalja et al., In our study, many students supported the government measure that requires that children should stay at home all the time to tackle the coronavirus epidemic. The WHO  has provOur findings contradict the results of previous literature, an assumption can be made that nonpharmacological strategies are useful from an individual perspective, for instance, fluid support, oxygen and ventilation support (Ali & Gatiti, 4.1One of the strengths of this study is using many students and recruiting them over social media to reach the highest number of students. The limitations of the study include using a cross‐sectional design, which limits the cause‐and‐effect relationship. Another limitation is using this study in Jordan, which limits the generalizability to other countries.5In summary, the students showed satisfactory‐level knowledge of COVID‐19 in children. The students had knowledge about the signs and symptoms of disease, ways of transmission, protection measures and satisfaction with measures to combat COVID‐19 in children, considering the importance of possessing knowledge about this ongoing global public health emergency.All authors participated in all steps of this study.This research did not receive a grant.The authors have no conflict of interest to disclose.


Eddy current (EC) testing has been selected as a standard candidate for detecting defects in conductive materials in the past few decades. Nevertheless, inventing EC probes capable of detecting minor defects has always been challenging for researchers due to the tradeoff between the probe dimensions and the strength of the EC generated on the surface of the test piece. Here, we use a copper core with a sophisticated design to converge the rotating EC at the tip of the copper core to detect small cracks in all directions in conductive materials. In this method, we can arbitrarily accommodate a large excitation coil so that a larger rotating uniform EC is generated in a small area of the test piece. Hence, the probe can detect cracks in all directions in conductive materials. It is an essential method for collecting information regarding defects in the maintenance field14.Small defects in structural components pose potential risks. Owing to the advantages of high speed, sensitivity, and efficiency15 noted that a straight-line pattern EC induced on the test piece surface can increase the signal-to-noise ratio (SNR). This technique is known as uniform eddy current (UEC) measurement in Japan. Meanwhile, this technique is called alternating current field measurement in America and Europe. Furthermore, the realization of self-differential and self-nulling characteristics for EC probes can reduce the effect of noise signals17. The typical UEC probe was invented by Hoshikawa and is called the Hoshi probe25. The structure of the Hoshi probe basically consists of a tangential rectangular excitation coil and a circular or rectangular detection coil. The principle of the UEC transducer is that when a defect exists in the material, it disrupts the distribution of the UEC and alters the magnetic flux through the detection coil.Hoshikawa et al.31. To date, UEC probes have had a disadvantage in detecting small defects because there is a requirement for a large excitation current intensity and thus a large structure of the probe for a strong EC to be generated on the test piece surface to increase the detection sensitivity. However, this affects the small defect detection ability because the induced EC distribution is too large compared to the size of small defects. In addition, instead of traditional ECT sensors, a highly sensitive flexible eddy current array sensor is also used to detect the surface microscopic defects34. Owing to the high-frequency conductivity measurement and large excitation amperage, the magnetic field diverges around the excitation coil and covers a large area resulting in high performance for micro-defects detection. Even so, flexible eddy current array probes usually have a small number of turns of copper wire. Therefore, flat coils need conductivity measurements at high frequencies to be able to achieve good performance . In this mode, there will be a lot of noise obviously and a shallow skin effect. Furthermore, to pursue the spatial resolution, a flexible eddy current array probe has a large spatial resolution, which will be disadvantageous when examining test pieces with a small area, especially as it cannot detect adjacent cracks. Therefore, in our previous study, an eddy current convergence (ECC) probe with a copper core having slits, hollows, and a plate fitted under the excitation coil was considered to create an extremely strong EC converging at the tip of the copper core36. Nevertheless, for the ECC probe of the previous work, the crack signal amplitude was significantly reduced when the EC lines were parallel to the crack length as compared to perpendicular to the crack length, leading to significantly affected evaluation of the crack's characteristics. A method to solve this problem is to use a pair of excitation cores with the same frequency and currents with a phase difference of 90° to generate a rotating EC on the surface of the specimen37. However, our previous study36 was hindered in creating EC rotation on the surface of the test piece because this rotation was not directly generated by the excitation coils but by the ECs converging at the tip of the copper core. In other words, to create a uniform rotating EC across the surface of the test piece, the ECs that converge at the tip of the copper core capable of uniform rotation must be controlled. Therefore, this study presents a novel rotating uniform eddy current convergence (RUECC) probe using a sophisticated design of a copper core that can create rotating ECs converging at the tip of the copper core, resulting in the generation of an extremely strong rotating EC on the test piece surface to detect small cracks in all directions. By adjusting the size and number of turns of the excitation coil and the structure of the copper core to produce ECs that converge at the tip of the copper core, the RUECC probe can overcome the disadvantage of ECC probes in the previous studies36. The ability to detect small defects in all directions with the probe is expected to significantly improve too. Besides, a circular detection coil adhering to self-nulling and self-differential characteristics and resulting in the RUECC probe eliminating noise signals . The finite element analysis was proformed to confirm the convergence of the eddy currents at the tip of the copper core. This study successfully obtained the RUECC at the tip of the copper core by manufacturing the copper core based on the finite element analysis results. Excellent defect detection ability was obtained with the special design of the copper core in comparison to the existing literature.To date, many researchers continue to investigate and develop new EC probes to achieve a high SNR to predict the size of increasingly minor defects. A ferrite core was applied as the core material of the excitation coil to increase the magnetic field amplitude and thus enhance the defect detection ability owing to its high permeabilityThe structures of the RUECC probe components are shown in Fig. x and y directions. The output amplitude signals were obtained by the single detection coil, processed with a two-phase lock-in amplifier (NF 5601B) and stored in a digital oscilloscope (Graphtec GL7000).The experimental setup is shown in Fig. 17 to enhance the sensitivity to the highest degree and to accurately assess the physical properties of cracks, especially for small cracks. However, two crack signal peaks were evident for the small cracks in specimen 2  and Path #6 (the length of cracks 4 mm deep in test specimen 2 was perpendicular to the x-axis) were obtained, as shown in Fig. To validate the crack detection ability of the RUECC probe in all directions to authenticate the rotating EC induced on the surface of the test piece by the RUECC probe, the measurement results of the RUECC probe in test piece 1 along Path #1 (the length of cracks 4 mm deep was perpendicular to the x-axis), Path #2 (the length of cracks 2 mm deep was perpendicular to the x-axis), Path #3 (the crack length was inclined 45° from the x-axis), and Path #4  were obtained, as shown in Fig. The overview measurement results show that the RUECC probe successfully detected all cracks in two test specimens. Based on the measurement result of paths #1 to #4 in test piece 1, It can be seen that the peak signal amplitude of cracks with a depth of 4 mm 40-4, 20-4) was twice that of cracks with a depth of 2 mm . Similarly, the maximum signal amplitude of cracks with a depth of 4 mm  was twice to that of cracks with a depth of 2 mm  was obtained by the measurement results of Paths #5 and #6 in test piece 2. For cracks with length 2 mm, since UECs was easier to divert cracks than crawling under cracks, the maximum signal amplitude was same between cracks with length 2 mm and depths 2 mm and 4 mm. This exhibits that the peak crack signal amplitude represents the crack depth. Moreover, the distance between two corner edges of the crack signal in test specimen 1 for a crack with a length of 40 mm  was twice that for a crack with a length of 20 mm . Likewise, the distance between the two corner edges of the signal crack for a crack in test piece 2 with a length of 10 mm  is double of a crack with a length of 5 mm . Hence, the distance between the two corner edges of the crack signal reflects the crack length. In addition, the distances between the two corner edges of the crack signals obtained for Path #4 (perpendicular to the crack length) were similar because all cracks had the same width of 0.5 mm. Therefore, the distance between two corner edges of the crack signal indicates the width of the crack when the obtained measurement results are perpendicular to the crack length. Although the output signal amplitude to 0.3 mV  when there is no crack under the RUECC probe, it is easy to distinguish the crack signal  are relatively similar, as shown in Fig.  x-axis, the probe had excellent sensitivity in its ability to detect cracks of different dimensions in all directions. This authenticated the ability to create strong converging ECs rotating at the tip of the copper core, leading to the generation of an extremely strong rotating EC on the surface of the test piece. Owing to this method, controlling the ECs generated on the test piece at the magnitude and direction to detect small cracks by adjusting the size and number of turns of the excitation coil and the structure of the copper core is straightforward. As a result, the RUECC probe can overcome the disadvantages of ECC probes in previous studies33 and possess the ability to detect small defects in all the directions with the probe with significant improvement.According to the measurement results, although there was a small effect on the results obtained with the RUECC probe when the crack length was approximately 45° from theTo authenticate the ability of ECs to converge at the tip of the copper core through the sophisticated design of the copper core and generate an RUEC on the test piece surface, the RUECC probe model with the same dimensions as in Fig. Figure T = 1/f and constant amplitude.Therefore, the total EC induced on the copper core is calculated by the equation:Figure Consider a particular case at time t = 0 when the amplitude of Pair #1 is zero while that of Pair #2 reaches its maximum value Fig. a,c. OwinT. Hence, the EMF generated on the circular detection coil also rotated, providing the ability to detect cracks in all directions.Figure 17. The output detection signal depends on the EMFs generated on the detection coil by the RUEC. The EMFs are generated in the interaction zone (the red dotted line) when the direction of the copper wire of the detection coil is parallel to the RUEC. There are two conditions: the balanced condition and unbalanced condition.Figure The balanced condition occurs when EMFs Supplementary Information 1.Supplementary Video 1.Supplementary Video 2.Supplementary Video 3.


Echinococcosis, also known as hydatid disease, is a zoonotic parasitic disease prevalent in pastoral areas, mainly involving the liver and lungs, and less frequently the bones and surrounding soft tissues. Diagnosis and treatment of bone hydatid disease is a challenge, and because of the insidious course of the disease, the lesions are often widely disseminated by the time patients seek medical attention.A 29-year-old woman presented with a painless mass that was gradually increasing in size in the cervical thorax. Imaging revealed an enlarged clavicle with multiple bone cortical defects and the existence of cysts in the soft tissues surrounding the clavicle, for which complete excision of the clavicle and the attached cysts was performed. There was no recurrence of the cyst within one year after the operation, and the patient felt well and had normal shoulder joint movement.Bone hydatid may appear in bones throughout the body, and cysts that leak from the bone into the surrounding soft tissues may spread at a relatively rapid rate. Prompt surgical removal of the affected bone and surrounding cysts is necessary for treatment. Echinococcosis is a zoonosis caused by parasitic infections of the genus Echinococcus, which may affect tissues and organs in various parts of the body. The infection rate of bone tissue is low, accounting for only 0.5% ~ 4% of the total number of cases, but it is very destructive . Spine, The patient was a 29-year-old female, a herder by occupation. The place of residence was a traditional husbandry area. About 3 months before admission, the patient developed a mass on the left neck with no obvious incentive, with a diameter of 2 cm and no obvious tenderness. The mass gradually increased within 3 months, and by the time of admission, the mass had grown to a size of 6 × 5 cm. One month after the appearance of the mass in the neck, the patient found that a mass with similar characteristics also appeared in front of the left shoulder joint, and gradually increased to an area of 5 × 4 cm on admission Fig. a. The paEchinococcosis is widely distributed in all continents except Antarctica. Western China has a wide distribution of traditional grazing areas and is a high prevalence area for the disease . Accordi


Scientific Reports 10.1038/srep09787, published online 10 April 2015Retraction of: The Editors have retracted this Article.1, which reports a different experiment by different authors. When asked by the Editors, the Authors were not able to provide the raw data and stated that the images in Figure 3(b) were obtained through a third party hired to perform some of the experiments for this study. Given the concerns about the veracity of the data, the Editors no longer have confidence in the results and conclusions presented in this Article.After the publication, the first author reached out to the Editors to point out that that the phase contrast microscopy image in Figure 3(b) appears to replicate panels that originally appeared in Figure 2(b) ofAll Authors agree to this retraction.


Non‐coplanar radiotherapy treatment techniques on C‐arm linear accelerators have the potential to reduce dose to organs‐at‐risk in comparison with coplanar treatment techniques. Accurately predicting possible collisions between gantry, table and patient during treatment planning is needed to ensure patient safety. We offer a freely available collision prediction tool using Blender, a free and open‐source 3D computer graphics software toolset. A geometric model of a C‐arm linear accelerator including a library of patient models is created inside Blender. Based on the model, collision predictions can be used both to calculate collision‐free zones and to check treatment plans for collisions. The tool is validated for two setups, once with and once without a full body phantom with the same table position. For this, each gantry‐table angle combination with a 2° resolution is manually checked for collision interlocks at a TrueBeam system and compared to simulated collision predictions. For the collision check of a treatment plan, the tool outputs the minimal distance between the gantry, table and patient model and a video of the movement of the gantry and table, which is demonstrated for one use case. A graphical user interface allows user‐friendly input of the table and patient specification for the collision prediction tool. The validation resulted in a true positive rate of 100%, which is the rate between the number of correctly predicted collision gantry‐table combinations and the number of all measured collision gantry‐table combinations, and a true negative rate of 89%, which is the ratio between the number of correctly predicted collision‐free combinations and the number of all measured collision‐free combinations. A collision prediction tool is successfully created and able to produce maps of collision‐free zones and to test treatment plans for collisions including visualisation of the gantry and table movement. Blender is a free and open‐source computer graphics software,22.1A model of a TrueBeam system was created in Blender. For this, measurements on a machine were taken with a tape measure and the machine was recreated using the integrated modelling tools inside Blender. A model for the gantry, the collimator, the table base and the table top was created. Additionally, the sensitive area of the laserguard of the TrueBeam was modelled using information from the TrueBeam manual as well as from measurements. The laserguard detects collisions using an infrared laser scanning device on a plane between the collimator and the patient. The sensitive area of the laserguard is V‐shaped with a notch in the middle.For the patient model, a patient library was generated based on average human proportions. For this, the proportions of a human base‐mesh was transformed using MakeHuman, a free and open‐source 3D character modelling software.2.21.x, y and z coordinates in the patient coordinate system. This difference is added to the table positions when the reference point is in the isocenter.The table positions are specified relative to a reference point on the head plate by measuring the difference between the treatment plan isocenter and the reference point in 2.The table positions are specified in absolute table values.To calculate the collision‐free zones, a python script using the Blender API was written, which simulates all possible gantry‐table angle combinations according to a specified resolution based on user input data. Using bounding volume hierarchies (BVHs), the script determines overlap of the 3D meshes of gantry and laserguard with the 3D meshes of the enveloping structures for table and patient model. Optionally, the user inputs safety margins in which case a collision is considered if the minimum distance between the 3D meshes is smaller than this margin. The initial table positions are specified with one of two ways:Because the table position varies between fractions, tolerances for pitch, roll and rotation and lateral, vertical and longitudinal table axes can be specified. The table position is shifted or rotated from its initial position plus and minus the specified tolerance in each axis. The tool then checks for collision also for each combination of tolerance shifts and rotations.A map with the predicted collision‐free zones is created as output. To ease the specification of the input data, a graphical user interface (GUI) is created using the scripting API of a research version of the Eclipse treatment planning system .2.31.Laserguard enabled, no patient model, head plate disabled, no additional margin, zero tolerance.2.Laserguard enabled, small male patient model with arms down, head plate enabled, no additional margin, zero tolerance.To validate the geometric model, collision predictions for each gantry‐table angle combination with a 2° resolution were generated for one initial table position with two different setups:On a TrueBeam, the table was moved to the initial table position and the table and gantry were rotated to each gantry‐table angle combination with a 2° resolution once with the table alone and once with an Alderson Radiation Phantom (ART) positioned on the table. Each of the gantry‐table angle combination was manually checked for a collision interlock either between the laserguard and the table or the gantry and the table.The predicted and measured collision interlocks were evaluated for each gantry‐table combination using the evaluation metrics shown in Table The number of TP, FN, FP and TN values over all gantry‐table combinations were determined and the true positive rate (TPR) and true negative rate (TNR) were calculated using the following equations. 2.4As a second application of the collision prediction tool, the fields of a treatment plan can be checked for collisions. The fields are checked for collision by giving the static or dynamic table angle and position, gantry angle and collimator angle as additional input. The tool then checks for collisions for the static position or along the dynamic path of the field using the same method as described above.For demonstration, a dynamic trajectory radiotherapy (DTRT) path with dynamic gantry rotation, table rotation and collimator rotation was created retrospectively for a head and neck (H&N) case using the method described by Fix et al.33.1A screenshot of the Blender model is shown in figure 3.2In Figure 3.3A DTRT path with a STD of 100 cm and a DTRT path with an extended STD of 110 cm were checked for collisions. The minimum distances between the gantry and the table and the gantry and the patient model are shown in Figures 4Using Blender, a model of a C‐arm linac was successfully created. Blender is a free and open‐source software, which allows broad access to a powerful computer graphics software toolset. The python API allows for easy automatization of simulations inside Blender. Using the python API, two applications for collision prediction were created. First, calculation of collision‐free zones, which allows to avoid unfeasible gantry‐table combinations during the treatment plan creation. Second, a plan check feature, which allows for checking a path of a treatment plan for specific table positions. This second feature is especially helpful, if the table position deviates from the expected position at the planning stage or if the plan was not created using the collision‐free maps. Additionally, tolerances for the table position can be considered in both applications. The tolerances allow to consider the daily table shifts in the collision prediction. In this work, the laserguard is integrated into the collision prediction tool using a model of the sensitive area of the laserguard, which is an advantage over collision prediction tools which use vendor provided data without any laserguardIn the collision check of plans feature, also videos of the simulation of the gantry and table movement are created, similar to the work of Suriyakumar et al and Wang et al.The Blender model was validated for one lateral, vertical and longitudinal table position by comparing predictions of collisions for all gantry‐table angle combinations to measurements. For a collision prediction tool, it is important, that the TPR is practically 100%, because otherwise collision might still occur which the tool did not predict. On the other hand, a low TNR indicates that the collision‐free space is reduced unnecessarily. In the balance, safety (a high TPR) is more preferred. In the validation, some false negatives did occur for collision interlocks with the laserguard but overall, the model is deemed adequate. The TNR is lower than the TPR due to some false positive areas around the smaller collision zones. This is mainly due to the complex shape of the collimator and the applicator mounting and the fact that the sensitive area of the laserguard has a notch, which is difficult to model correctly.In this work, the patient is modelled by relying on averaged data of human proportions and predefined patient positionings. Because of this simplification, collision interlocks between the patient and gantry might still occur with the custom positioning of the patient, such as having their arms in a different location, and not a wide enough margin around the patient model is applied. To model the patient more accurately, others have suggested to use a commercial 3D surface scanner.5In this work, a collision prediction tool using Blender is successfully developed. The prediction tool is able to predict collision zones as well as check treatment plans for collisions including laserguard and positioning variations. Additionally, videos of the gantry and table movement of treatment plans can be produced and minimum distances between gantry, table and patient model are visualised. The tool facilitates a smoother clinical workflow with less replannings due to collision interlocks.Michael K. Fix and Peter Manser concieved the initial idea. Gian Guyer, Silvan Mueller, Remo Schmid and Yanick Wyss performed the measurements for this study. Gian Guyer and Yanick Wyss created the tool and wrote the code. Gian Guyer, Silvan Mueller and Jenny Bertholet performed the validation. Marco F. M. Stampanoni, Peter Manser and Michael K. Fix supervised the project. Gian Guyer wrote the manuscript with critical feedback from all co‐authors.The authors declare no conflict of interest.Supplementary materialClick here for additional data file.


The coronal magnetic field near the solar surface is structured on scales associated with ‘supergranulation’ convection cells, whereby descending flows create intense fields. The energy density in these ‘network’ magnetic field bundles is a candidate energy source for the wind. Here we report measurements of fast solar wind streams from the Parker Solar Probe (PSP) spacecraft6 that provide strong evidence for the interchange reconnection mechanism. We show that the supergranulation structure at the coronal base remains imprinted in the near-Sun solar wind, resulting in asymmetric patches of magnetic ‘switchbacks’8 and bursty wind streams with power-law-like energetic ion spectra to beyond 100 keV. Computer simulations of interchange reconnection support key features of the observations, including the ion spectra. Important characteristics of interchange reconnection in the low corona are inferred from the data, including that the reconnection is collisionless and that the energy release rate is sufficient to power the fast wind. In this scenario, magnetic reconnection is continuous and the wind is driven by both the resulting plasma pressure and the radial Alfvénic flow bursts.The fast solar wind that fills the heliosphere originates from deep within regions of open magnetic field on the Sun called ‘coronal holes’. The energy source responsible for accelerating the plasma is widely debated; however, there is evidence that it is ultimately magnetic in nature, with candidate mechanisms including wave heating Measurements of fast solar wind streams from the Parker Solar Probe spacecraft provide strong evidence for the interchange reconnection mechanism being responsible for accelerating the fast solar wind. However, the footpoints of the previous PSP encounter were at high latitudes on the far side of the Sun, so that the magnetic structure of the cells and their connectivity to the spacecraft could not be determined, preventing a complete analysis of the source of the microstreams.Recent measurements from the NASA Parker Solar Probe (PSP) showed that the solar wind emerging from coronal holes is organized into ‘microstreams’ with an angular scale (5–10°) in the Carrington longitudeRS) of the photosphere. Figure 11, energetic ion12 and magnetic field measurements13 made near perihelion. An ion spectrogram in Fig. 15 whose duration decreases from around 10 h to around 2 h as the spacecraft approaches perihelion. Data in Fig. AHe = nα/np , which is similarly modulated. The high first ionization potential of helium requires that the alpha particle abundance is frozen-in at the base of the corona or in the chromosphere16, so these microstream structures are organized at the source of the wind itself. The radial component of the interplanetary magnetic field in Fig. 19 , PSP came within 12.3 solar radii  prediction35. With ambient temperatures of around 100 eV, the reconnection electric field is therefore around three orders of magnitude above the Dreicer runaway field. In this regime, collisions are too weak to limit electron acceleration, and collisionless processes dominate. The rate of magnetic energy release from interchange reconnection is given by VrB2/4π ≈ 5 × 105 ergs cm−2 s−1 using B = 4.5 G and Vr = 3 km s−1. This is comparable to that required to drive the high-speed wind, which is around 105–106 ergs cm−2 s−1.To address whether the rate of energy release is sufficient to drive, the wind we estimate the reconnection inflow rate 9 and illustrated in the schematic in Fig. 36. Reconnection between the closed magnetic flux of the Earth and ‘open’ flux in the solar wind is an analogue of coronal interchange reconnection.Thus through the PSP observations, the Solar Dynamics Observatory/Helioseismic and Magnetic Imager (SDO/HMI) surface magnetic field measurements and well-known characteristics of magnetic reconnection, we have established that interchange reconnection is sufficient to drive both the ambient base solar wind flow through the radial pressure drop and the microstream bursts that lie on top of this flow. Further tests of the reconnection scenario concern the structuring of the flow bursts and the production of energetic protons and alphas. A key observation reported in the E06 data16. Energy flux spectra of both species are shown in Fig. mimimi−1 estimate for VA based on the amplitude of the bursty flows measured at 13.4 Rs. That the two values of mi−1.Finally, the spectrum of energetic protons and alphas has been calculated from the interchange reconnection simulations. The simulation includes fully stripped alpha particles that are 5% by number, similar to the solar atmosphere39 and at the same time produces the turbulent velocity bursts that ride this outflow27. Extended Data Fig. 2 or other magnetic structures5 that can be dissipated higher in the coronal to further drive the bulk outflow37. However, the in situ data from reconnection in the Earth’s magnetosphere40 and at the heliospheric current sheet41 show strong local plasma energization rather than wave generation. The time asymmetry that characterizes the bursty flows9 and the spectral indices of the power-law distributions of energetic ions are in remarkably good agreement with the interchange reconnection simulation data, in which local plasma energization dominates waves and turbulence. Still, three-dimensional simulations with greater scale separation might show stronger magnetic turbulence. In either scenario, interchange reconnection is the likely energy drive mechanism of the fast solar wind. Recent remote-sensing measurements43 also support the interchange magnetic reconnection scenario. We note that structured microstreams and magnetic switchbacks are present throughout the inner heliosphere measured by the PSP and that the primary difference between the slow and fast solar wind may lie in the magnetic topology of the underlying coronal hole.The picture that emerges is that reconnection directly heats the ambient coronal plasma sufficiently to drive the bulk outflow17 was run using an Air Force Data Assimilative Photospheric Flux Transport–Global Oscillation Network Group (ADAPT–GONG) magnetogram46 from 21 November 2022, with a source surface height set to the canonical value of 2.5 RS19 by means of the open-source pfsspy47 software. The footpoint mapping from the PSP down to the solar surface followed the methodology48 comprising a ballistic heliosphere50 and the PFSS domain from 2.5 RS down to the photosphere51.To generate the footpoints shown in Figs. 52. This correspondence is clearly shown in Fig. The results for PSP E10 were distinct and compelling. As shown in Figs. 11 on PSP. The proton spectrum in Fig. We use proton and alpha particle measurements from the Solar Wind Electrons Alphas and Protons (SWEAP) instrument suiteBR at the perihelion of E10, as shown in Fig. BR over the first five PSP orbits have established an R−2 scaling for the field45, consistent with the conservation of the radial magnetic flux. However, deviations from this scaling are expected close to the Sun. Specifically, because closed flux occupies a substantial fraction of the solar surface, the open flux will be compressed into a reduced fraction of the solar surface, which will lead to greater compression of the magnetic field near the solar surface. A rough estimate of the increased magnetic field compression can be obtained by averaging the radial magnetic field obtained from the PFSS model during the E10 perihelion. The radial dependence of this averaged field is shown in Extended Data Fig. Rs, the outer boundary of the PFSS grid, down to just above the solar surface is around 26, which is well above the compression of around 6.25 from the R−2 dependence. Thus, we assume that the R−2 describes the radial dependence from R = 13.4 Rs to 2.5 Rs and take the compression of 26 from 2.5 Rs to just above the solar surface. The projection of the 600-nT field down to the solar surface is around 4.5 G, which is in reasonable agreement with the strength of the solar surface magnetic field shown in Fig. The strength of the magnetic field that drives interchange reconnection will control the rate of magnetic energy release and the spectra of energetic particles produced. Although the SDO/HMI observations make known the structure of the magnetic field in the low corona, these measurements do not show the strength of the magnetic field that is actually undergoing reconnection because there is substantial variation of the field strength along the surface. To estimate the strength of the magnetic field driving the flow bursts measured by the PSP, we project the measured magnetic field at the PSP and project this magnetic field down to the solar surface. The radial magnetic field 53). The MHD model is not adequate to explore the particle energization documented in the PSP data. We limit the calculations to a two-dimensional system with an initial magnetic geometry that leads to reconnection between open and closed flux low in the corona54. Because of constraints on the domain size possible with the PIC model, there is no gravity in the simulations, so the model does not describe the complete dynamics of the solar wind drive mechanism. In addition, line-tied boundary conditions are not imposed at the nominal coronal surface. Thus, the model is not a complete description of interchange reconnection in the low corona, but will provide information on the dynamics of collisionless reconnection, the structure of the outflow exhaust, the bulk heating and the spectra of accelerated particles. We include alpha particles (5% by number) so that the spectra of protons and alphas can be compared.Our estimate of the rate of interchange reconnection based on projections of the PSP observations back to the low corona suggest that reconnection there is deeply in the collisionless regime. To explore the structure of the interchange reconnection exhaust and the resulting energetic proton and alpha spectra measured at the PSP, we use the PIC model p3d  with a low plasma density (0.1 n0) and an adjacent region with higher density that is a cylindrical equilibrium. The detailed initial state has been described previously23, so the governing equations are not repeated here. The peak magnetic field of the cylindrical equilibrium is 0.76 B0 with a peak density of n0. The temperatures are uniform with Te = Tp = Ta = 0.06 mpVA0 the Alfvén speed based on B0, n0 and the proton mass mp. Thus, in the initial state, the plasma pressure is small compared with the magnetic pressure, as expected in the corona. The guide field Bz is non-zero everywhere with a profile that balances the pressure and tension forces. The strength of the guide field can be varied by choosing its value in the region of vertical flux. Its value does not substantially affect the overall structure and dynamics of reconnection shown in Fig. B0. Simulations with a weaker (stronger) guide field produced harder (softer) spectra.The initial state for the simulation consists of a band of vertical flux  and the proton inertial scale dp = L/163.84. As has been established in earlier papers, the results are not sensitive to these values34. The radius of the cylindrical magnetic field is 60 dp and the grid scales are 0.02 dp in both space directions, with around 400 particles per cell.The results of the simulation are presented in normalized units: times to the Alfvén transit time across the domain of scale length VA0 and mpVA0 where reconnection is taking place, be established. As described in the main text, we use two distinct approaches for estimating VA0. The first comes from the amplitude of the flow bursts measured by the PSP at 13.4 Rs, which have values of around 300 km s−1. The second comes from comparing the proton spectra from the simulation and that measured with SPAN-Ion. Specifically, we equate the low energy limit of the proton power-law spectrum from the simulation and the observations. This yields mpVA0 = 370 km s−1. Thus, the two approaches yield comparable values, which enables us to directly compare the simulation results with the observations. The spectral indices of around −8 for the proton and alpha energy fluxes from the simulation are independent of this normalization. That they are in approximate agreement with the observational data is strong support for the interchange reconnection model for these energetic particles. We further note that a simulation with half of the domain size (L = 81.92 dp) produced power-law spectra with similar spectral indices.Because the velocities and energies in the simulation are normalized to the Alfvén speeds 2 or other forms of magnetic structures5 are injected into the low corona and the heating associated with this turbulence produces the pressure required to drive the wind. As interchange reconnection is often invoked as the source of this turbulence, it is important to explore whether a substantial fraction of released magnetic energy appears as magnetic turbulence versus direct particle energization or bulk flow. Shown in Extended Data Fig. mpMany of the global models that have been used to explore the acceleration of the solar wind have been based on the assumption that Alfvén wavesAny methods, additional references, Nature Portfolio reporting summaries, source data, extended data, supplementary information, acknowledgements, peer review information; details of author contributions and competing interests; and statements of data and code availability are available at 10.1038/s41586-023-05955-3.