Radiographs and MRI of the Cervical Spine in Juvenile Idiopathic Arthritis: A Cross-Sectional Retrospective Study

Background: Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease among children. In some patients, cervical spine arthritis remains a serious and chronic manifestation of JIA. The aim of this study was to assess the frequency of cervical spine lesions on radiographs and MRI in JIA patients with clinical signs of cervical spine involvement and to verify if with the addition of MRI, the use of radiographs could be abandoned. Methods: This retrospective study evaluated consecutive 34 children (25 girls; aged 6–18 years, median 15.5 years) with JIA and with clinical involvement of cervical spine. In each patient, both radiographs and MRI of the cervical spine were performed. Imaging findings were correlated with clinical and laboratory data. Results: The cervical spine was affected in 35% of patients. The most frequent lesions were subaxial subluxations (SAS; 24%), apophyseal joint ankylosis (9%), and C1/C2 joint lesions (9%). Anterior atlanto-axial subluxation (AAS) was diagnosed only by radiography, and most of the SAS were seen on radiography, whereas only a few on MRI. Reversely, C1/C2 soft tissue involvement were seen on MRI only. Cervical spine involvement was associated with raised ESR (p = 0.012) and CRP (p = 0.014). Conclusions: The cervical spine lesions are still frequent complication of JIA affecting up to 35% of JIA patients. Most of them develop serious complications, such as AAS and ankylosis. Despite advantages of MRI in terms of the imaging of the atlanto-axial region radiography shows superiority in diagnosis of AAS and SAS.

TRANSIENT SIGNAL IN THE AXIAL DOMAIN OF THE ELECTRIC LINE FOR GEOELECTRIC CONDITIONS OF THE OFFSHORE AREA

The behavior of the transient process (TP) signal in the axial region of the electric line located in the water layer of the sea shelf is described.

Numerical simulation of heat transfer processes during single crystal growth by the Bridgman - Stockbarger method in fixed and rotating crucibles

Численно методом конечных элементов исследованы процессы кристаллизации кремния в плоскодонных неподвижных и равномерно вращающихся графитовых цилиндрических тиглях в режимах сопряженного конвективного теплообмена. Процессы кристаллизации кремния изучены при фиксированной скорости опускания тигля в холодную зону и различных скоростях его вращения. Опускание тигля имитировалось перемещением точки излома в распределении температуры на внешней стороне стенок тигля. Точка излома - это граница перехода от нагретого до начальной температуры участка стенки к области с заданным градиентом температуры. Использованы адаптивные сетки на треугольниках, отслеживающие положение фронта кристаллизации на каждом временном шаге. Использован пакет программ собственной разработки. The dependence of both spatial shape and intensity of the convective flow of silicon melt during the growth of a silicon ingot by the Bridgman-Stockbarger method was studied numerically by the finite element method. Stationary and uniformly rotating graphite crucible in conjugate convective heat transfer regines were examined. The simulation was carried out on the basis of dimensionless system of equations for the thermogravitational convection in the Boussinesq approximation using the bipolar approach. In the mixed convection regine, the system of equations was augmented by an equation for the azimuthal velocity. Adaptive grids on triangles were used to track the position of the crystal-melt interface at each time step. The calculations were carried out at a constant rate of lowering the crucible from the hot to the cold zone, equal to 2.81 cm/h, and at a constant temperature gradient equal to 35 K/cm. Lowering the crucible was simulated by moving the inflection point in the temperature distribution on the outside of the crucible walls. The range of angular velocities of crucible rotation from 0 to 10 rpm is considered. It is shown that as the angular velocity of crucible rotation in the axial region increases, both the velocity of the downward flow arising in the regines of thermogravitational convection gradually and the convective heat flux to the crystal-melt interface decrease. As a result, in the range of angular velocities from 2 to 10 rpm, the shape of the crystal-melt interface gradually approaches to the one typical for the thermal conductivity regime. It is shown that at the initial stage of the process at an angular velocity of 10 rpm in the axial region of the cooled crucible bottom, the nucleation of a single crystal is possible.

On magma supply and spreading modes at slow and ultraslow mid-ocean ridges

<p>The availability of magma is a key to understand mid-ocean ridge tectonics, and specifically the distribution of the two contrasted spreading modes displayed at slow and ultraslow ridges (volcanically-dominated, and detachment fault-dominated). The part of the plate divergence that is not accommodated by magma emplaced as gabbros or basaltic dikes is taken up by normal faults that exhume upper mantle rocks, in many instances all the way to the seafloor. </p><p>Magma is, however, more than just a material that is, or is not, available to fill the gap between two diverging plates. It is the principal carrier of heat into the axial region and as such it may contribute to thin the axial lithosphere, hence diminishing the volume of new plate material formed at each increment of plate separation. Magma as a heat carrier may also, however, if emplaced in the more permeable upper lithosphere, attract and fuel vigorous hydrothermal circulation and contribute instead to overcooling the newly formed upper plate (Cochran and Buck, JGR 2001). </p><p>Magma is also a powerful agent for strain localization in the axial region: magma and melt-crystal mushes are weak; gabbros that crystallize from these melts are weaker than peridotites because they contain abundant plagioclase; and hydrothermally-altered gabbros, and gabbro-peridotite mixtures, are weaker than serpentinites because of minerals such as chlorite and talc. As a result, detachment-dominated ridge regions that receive very little magma probably have a stronger axial lithosphere than detachment-dominated ridge regions that receive a little more magma. </p><p>Because magma has this triple role (building material, heat carrier, and strain localization agent), and because it is highly mobile (through porosity, along permeability barriers, in fractures and dikes), it is likely that variations in magma supply to the ridge, in time and space, and variations in where this magma gets emplaced in the axial plate, cause a greater diversity of spreading modes, and of the resulting slow and ultraslow lithosphere composition and structure, than suggested by the first order dichotomy between volcanically-dominated and detachment-dominated spreading. </p><p>In this talk I illustrate these points using results of recent studies at the Mid-Atlantic and Southwest Indian ridges.</p>

RELAP5-3D Sensitivity Studies of Incorporating Axial Boron Gradients Into a Heater Tube Experiment for Pool Boiling CHF Testing in TREAT

Nuclear reactor designs are governed by postulated accident events that may occur during their operational lifetime. One type of incident is a reactivity-initiated accident (RIA), during which a sudden surge of power in the fuel components within the core may result in the latter exceeding its cooling capabilities. This could lead to a departure from nucleate boiling (DNB) event which results in a significant decrease in heat transfer capabilities. Preventing the occurrence of a DNB crisis requires a fundamental understanding of the cladding-to-coolant heat transfer under fast transient conditions, as well as the governing hydrodynamic and design parameters that influence when the critical heat flux (CHF) will be exceeded. Presently, large uncertainties in computer models used to predict CHF have led to conservative safety limits governing light-water reactor (LWR) designs. The Idaho National Laboratory (INL) is currently leading a combined effort that takes advantage of the restart of the Transient Reactor Test (TREAT) facility, to better understand the mechanism of CHF under in-pile pool boiling conditions. The goal of this laboratory directed project is to use the unique capabilities of TREAT coupled with a non-fueled nuclear heated borated stainless-steel 304 tube experiment within an experimental capsule. The borated tube will induce CHF in the surrounding coolant when subjected to a power pulse within the TREAT. The impacts of rapid surface heating effects as well as radiation-induced surface activation (RISA) will be experimentally investigated. This feature is a continuation to previous thermal hydraulics analysis that was conducted to inform on a test matrix for the design of the borated heater experiment. The borated tube was used in place of a solid rod so that the center axial region can be instrumented to allow for better experimental analysis. Therefore, it is desirable to design this rodlet so that the maximum heat flux occurs at the center of the axial length of the rod. The work presented here analyzes the potential to integrate axial boron gradients within this tube to shape its power curve. Several generic axial power shapes were initially considered. Natural boron concentrations between 0.1–2.0 wt.% were analyzed and a power coupling factor (PCF) was calculated for each. A self-shielding study was conducted to develop radial power profiles for several boron concentrations. These were then applied to three different power pulses to determine how these two parameters influence the chosen axial heat flux curve. Variations in the initial coolant temperature were investigated. Lastly, how the shape of the generic curve is affected following a DNB event was also studied. Two different CHF cases were included within the scope of this analyses; one during which CHF was exceeding along the entire axial region of the rod, and another where the former occurred at the center region only. The behavior of the curve overtime was investigated.

On spreading modes and magma supply at slow and ultraslow mid-ocean ridges

<p> </p><p><span>The availability of magma is a key to understand mid-ocean ridge tectonics, and specifically the distribution of the two contrasted spreading modes displayed at slow and ultraslow ridges (volcanically-dominated, and detachment fault-dominated). The part of the plate divergence that is not accommodated by magma emplaced as gabbros or basaltic dikes is taken up by normal faults that exhume upper mantle rocks, in many instances all the way to the seafloor. </span></p><p><span>Magma is, however, more than just a material that is, or is not, available to fill the gap between two diverging plates. It is the principal carrier of heat into the axial region and as such it may contribute to thin the axial lithosphere, hence diminishing the volume of new plate material formed at each increment of plate separation. Magma as a heat carrier may also, however, if emplaced in the more permeable upper lithosphere, attract and fuel vigorous hydrothermal circulation and contribute instead to overcooling the newly formed upper plate (Cochran and Buck, JGR 2001). </span></p><p><span>Magma is also a powerful agent for strain localization in the axial region: magma and melt-crystal mushes are weak; gabbros that crystallize from these melts are weaker than peridotites because they contain abundant plagioclase; and hydrothermally-altered gabbros, and gabbro-peridotite mixtures, are weaker than serpentinites because of minerals such as chlorite and talc. As a result, detachment-dominated ridge regions that receive very little magma probably have a stronger axial lithosphere than detachment-dominated ridge regions that receive a little more magma. </span></p><p><span>Because magma has this triple role (building material, heat carrier, and strain localization agent), and because it is highly mobile (through porosity, along permeability barriers, in fractures and dikes), it is likely that variations in magma supply to the ridge, in time and space, and variations in where this magma gets emplaced in the axial plate, cause a greater diversity of spreading modes, and of the resulting slow and ultraslow lithosphere composition and structure, than suggested by the first order dichotomy between volcanically-dominated and detachment-dominated spreading. </span></p><p><span>In this talk I illustrate these points using results of recent studies at the Mid-Atlantic and Southwest Indian ridges.</span></p>

Earth Space, Planetary Geopolitics, and World Governments

Contrary to expansionist views, space around Earth, dominated by its gravitational attraction, is part of the planet, its astrosphere. While solar space is vast, the practical geography of Earth space is small because effective distances are so small. Analogies with terrestrial oceans and frontiers are very misleading. Space activities have amplified, not reduced, global closure. The applied propositions of geopolitics indicate the superiority of Clarke-Sagan over von Braun programs for achieving security. The deployment of ballistic missile space weapons has increased the probability of catastrophic nuclear war. Escaping nuclear vulnerability with a vast orbital Earth Net is unlikely to be successful. Orbital space is an axial region with integral tendencies, but realizing planetary military dominance is unlikely. Building Orbita of large orbital civil infrastructures will probably require or produce hierarchical world government. Anticipations of Earth identity-formation remain unrealized. Information satellites support a repressive planetary panopticon, but intensive expansion in microspace enables continued growth.

Architecture, process, and environmental diversity in a late Cretaceous slope channel system

ABSTRACT Arroyo San Fernando, on the Pacific coast of Baja California, Mexico, provides a superb view of the architecture of a Maastrichtian active margin slope channel system and the record of its evolution through a third-order sea-level cycle. The succession is organized into architectural building blocks (channel-complex sets) consisting of a channel belt with an axial region and a channel-belt margin of terraces and internal levees. The channel belt is confined by an external levee on one side and by an erosion surface into the slope on the other. Each channel-complex set can be subdivided into three stages of evolution: Stage I consists of highly amalgamated coarse-grained channel complexes, Stage II consists of gravelly meander belts with marginal and stratigraphically intervening thin-bedded turbidites, and Stage III consists of mudstones representing abandonment. This succession is associated with repeated and therefore predictable changes in architecture, facies distribution, inferred seafloor morphology, and sedimentary process. We describe variability in the sedimentology, ichnology, palynology, provenance, and inferred sedimentary processes between and within these architectural elements. Channel formation and fill are attributed to erosion, sediment transport, and deposition by turbidity currents and lesser debris flows. Ichnology indicates enhanced oxygenation and supply of organic material, substrate type, and turbidity within the channel belt; the axial region can be differentiated from the terraces by differing response to turbidity-current intensity. Levee environments show ichnological gradients away from the channel towards background slope. Palynology reflects confinement of the supply of terrigenous material to the channel belt, but is also indicative of stratification within the turbidity-currents, as is the distribution of heavy minerals. Provenance is from the extinct part of the continental-margin arc to the east, via high-gradient gravelly streams and across a steep shoreline, with direct supply of coastal material to deep water. Architectural hierarchy bears comparison with other slope channel systems, but in common with them the fill represents only a small fraction of the time that the system was active.

Study of stress-strain state during cross-wedge rolling with one tool

The peculiarity of cross-wedge rolling with one tool is the workpiece deformation with one tool and the fact that the workpiece is not supported with the tool from the opposite side. On both sides of the tool outside the contact with the workpiece, the workpiece is fixed with pairs of upper and lower tools, by means of which the axis of the workpiece is held in a constant position. Such conditions of rolling qualitatively change the deformation zone and, as a result, the stress-strain state.The change in the stress-strain state was qualitatively estimated by comparing the fields of slip lines in the traditional two-tools cross rolling and one-tool cross rolling. One-tool cross rolling increases the normal and average stress at the contact by 7.8–14.5 %, changes the average stress of the specimen from tensile to compressive one in the axial region. This circumstance significantly increases the resource of plasticity and allows rolling metals with limited plasticity without opening the axial cavity. Comparative studies of the stress-strain state from the traditional two-tools cross-wedge rolling and one-tool cross-wedge rolling in the axial region of the workpiece have been carried out by computer simulation.

Messorocaris, a new sanctacaridid-like arthropod from the middle Cambrian Wheeler Formation (Utah, USA)

The Drumian Wheeler Formation preserves one of the most diverse exceptionally preserved faunas of the Cambrian period. Here we describe Messorocaris magna gen. et sp. nov., a new non-biomineralizing arthropod from this formation tentatively assigned to the family Sanctacarididae. The new taxon exhibits a vaulted axial region, and wide pleural regions forming sickle-shaped lateral extensions in the trunk, a character particularly distinctive within the Sanctacarididae. This description provides an opportunity to stress the fact that the ‘Wheeler fauna’ encompasses two distinct assemblages, as confirmed by similarity analysis. These contemporaneous faunas lived at different bathymetries, and should be treated as separate entities.