First observations and performance of the RPW instrument onboard the Solar Orbiter mission

The Radio and Plasma Waves (RPW) instrument on the ESA Solar Orbiter mission is designed to measure in situ magnetic and electric fields and waves from the continuum up to several hundred kHz. The RPW also observes solar and heliospheric radio emissions up to 16 MHz. It was switched on and its antennae were successfully deployed two days after the launch of Solar Orbiter on February 10, 2020. Since then, the instrument has acquired enough data to make it possible to assess its performance and the electromagnetic disturbances it experiences. In this article, we assess its scientific performance and present the first RPW observations. In particular, we focus on a statistical analysis of the first observations of interplanetary dust by the instrument’s Thermal Noise Receiver. We also review the electro-magnetic disturbances that RPW suffers, especially those which potential users of the instrument data should be aware of before starting their research work

Fine dust emissions from active sands at coastal Oceano Dunes, California

Sand dunes and other active sands generally have a low content of fine grains and, therefore, are not considered to be major dust sources in current climate models. However, recent remote sensing studies have indicated that a surprisingly large fraction of dust storms are generated from regions covered by sand dunes, leading these studies to propose that sand dunes might be globally relevant sources of dust. To help understand dust emissions from sand dunes and other active sands, we present in situ field measurements of dust emission under natural saltation from a coastal sand sheet at Oceano Dunes in California. We find that saltation drives dust emissions from this setting that are on the low end of the range in emissions produced by non-sandy soils for similar wind speed. Laboratory analyses of sand samples suggest that these emissions are produced by aeolian abrasion of feldspars and removal of clay-mineral coatings on sand grain surfaces. We further find that this emitted dust is substantially finer than dust emitted from non-sandy soils, which could enhance its downwind impacts on human health, the hydrological cycle, and climate.</p

Comparison of Helicobacter Pylori Genotypes Obtained from the Oropharynx and Stomach of the Same Individuals -A Pilot Study

R e c e i ve d M a rc h 3 , 2 0 12 ; A c c e p t e d Ju n e 2 5 , 2 0 1 2 . Key words: Helicobacter pylori -Real-time PCR -Genotyping -OropharynxStomach -Comparison Abstract: Helicobacter pylori has been recently detected in the oral cavity and oropharynx. However, the role it plays in oral and oropharyngeal pathogenesis remains unclear. The virulence of H. pylori strains can be distinguished according to the virulence factors genes carried. Our research has been focused on realtime PCR analysis of cagA and vacA genes of H. pylori strains in tonsils and tonsillar squamous cell cancer and their comparison with H. pylori strains obtained fro

Erratum: The solar orbiter radio and plasma waves (RPW) instrument (Astronomy and Astrophysics (2020) 642 (A12) DOI: 10.1051/0004-6361/201936214)

The erratum concerns Fig. 9 entitled "Antenna radio-electrical properties" for which some of the parameters are not correct. The new figure with new parameters is provided in Fig. 1 of this corrigendum. Fig. 1. Corrected Antenna radio-electrical properties. (Figure Presented)

Mandibular reconstruction : biomechanical strength analysis (FEM) based on a retrospective clinical analysis of selected patients

Restoration of mandible discontinuity defects continues as a challenge for maxillofacial surgeons. Despite the development of algorithms for reconstruction plates fixation and autogenous grafting techniques, complications are still encountered including screw loosening, bone resorption or delayed/incomplete union. The aim of the study was to analyze the possibility of obtaining bone union in the aspect of biomechanical conditions of two mandible reconstructions using an autogenous iliac crest bone graft stabilized with a reconstruction plate, and to attempt to predict patient outcomes based on strength parameters obtained by the finite element analysis. The authors of the present paper were trying to determine to what extent the reconstruction model and changes occurring in hard tissues of the bone and autogenous graft (simulated by changes in material properties) might help predict individual patient courses. The effort of reconstruction plates was defined using the values of the von Mises stress (σHMH) while the effort of bones was determined based on the values of strain intensity εint. The results of the above mentioned simulations are presented in the form of bar graphs and strain/stress distribution maps. Our strength analyses indicate that uncomplicated healing of grafts fixed with reconstruction plates requires that the initial loading of the stomatognatic system should not result in strain intensity exceeding 20–40 [×10–4]. This range of strain intensity evokes an increase in the mineral phase. The state of nonunion between the mandibular bone and the graft might result from prolonged periods of insufficient loading of the mandible during treatment

Estudio del Miedo en Pacientes Frente a la Extracción del Tercer Molar

Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Cirugía y Traumatología Bucomaxilofacial I. Buenos Aires, Argentina.Universidad de Buenos Aires. Facultad de Psicología. Maestría en Psicología Educacional. Buenos Aires, Argentina.Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Cirugía y Traumatología Bucomaxilofacial I. Buenos Aires, Argentina.Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Cirugía y Traumatología Bucomaxilofacial I. Buenos Aires, Argentina.Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Cirugía y Traumatología Bucomaxilofacial I. Buenos Aires, Argentina

Numerical Study of Shear Stress Distribution Over Sand Ripples Under Terrestrial and Martian Conditions

Flat sand beds subjected to wind stress are unstable, and the wind action results in two types of aeolian sand ripples: normal ripples and megaripples. The distinction between the two types is based on two characteristics: i) the normal ripple pattern usually has a wavelength of up to 30 cm, while the megaripple wavelength is on the order of meters; and ii) unimodal distributions of sand grain size lead to normal ripples, while bimodal distributions result in megaripples. On Mars, the distinction between the two types is more difficult to ascertain because the length scales of normal ripples and megaripples can overlap, and often, there is no detailed information regarding their grain size distribution. Unlike normal ripples, megaripples show transverse instability, whose mechanism remains elusive, resulting in a much larger sinuosity of the crestline than normal ripples. In this study, we investigate the megaripples’ transverse instability by using field measurements, wind tunnel experiments and numerical simulations of a three-dimensional ripple model. We show that (a) coarse grains accumulate at megaripple crests, with a corresponding reduction of the lateral sand transport along the crest, and (b) the transverse instability of megaripples is generated by a positive feedback between the height of the crest and the accumulation of coarse grains, with more grains accumulating on the higher portions of the crest. The outcomes of this positive feedback are that the thickness of the coarse grain armoring layer along the crest is not uniform and that it correlates with the crest height. In turn, these height differences drive the transverse instability such that higher portions of the ripple migrate more slowly than the lower sections, creating a wavy crestline. An analysis of Martian ripple images shows variations in the sinuosity index, suggesting that this characteristic can be useful in distinguishing between normal ripples and megaripples on Mars

The origin of the transverse instability of aeolian megaripples

Flat sand beds subjected to wind stress are unstable, and the wind action results in two types of aeolian sand ripples: normal ripples and megaripples. The distinction between the two types is based on two characteristics: i) the normal ripple pattern usually has a wavelength of up to 30 cm, while the megaripple wavelength is on the order of meters; and ii) unimodal distributions of sand grain size lead to normal ripples, while bimodal distributions result in megaripples. On Mars, the distinction between the two types is more difficult to ascertain because the length scales of normal ripples and megaripples can overlap, and often, there is no detailed information regarding their grain size distribution. Unlike normal ripples, megaripples show transverse instability, whose mechanism remains elusive, resulting in a much larger sinuosity of the crestline than normal ripples. In this study, we investigate the megaripples’ transverse instability by using field measurements, wind tunnel experiments and numerical simulations of a three-dimensional ripple model. We show that (a) coarse grains accumulate at megaripple crests, with a corresponding reduction of the lateral sand transport along the crest, and (b) the transverse instability of megaripples is generated by a positive feedback between the height of the crest and the accumulation of coarse grains, with more grains accumulating on the higher portions of the crest. The outcomes of this positive feedback are that the thickness of the coarse grain armoring layer along the crest is not uniform and that it correlates with the crest height. In turn, these height differences drive the transverse instability such that higher portions of the ripple migrate more slowly than the lower sections, creating a wavy crestline. An analysis of Martian ripple images shows variations in the sinuosity index, suggesting that this characteristic can be useful in distinguishing between normal ripples and megaripples on Mars