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The potentially hazardous asteroid 99942 Apophis will have a very close approach to the Earth in 2029. The encounter on its own may provide measurements of Earth's effects on Apophis' surface and also contribute to the improvement of some physical characteristics of the asteroid. In a previous work, we assumed the existence of a hypothetical disc of particles around Apophis before the 2029 encounter, and identified the particles that would escape from the gravity domain of Apophis due to the Earth's gravitational perturbation during the close encounter. In the current work, we investigate the possibility of a meteor activity originating from this event. We study the orbital evolution of these particles computing the MOIDs of the particles with respect to the Earth for the following 200 yr. Our results are not favourable for a meteor activity on Earth. However, a meteoroid activity on the Moon might happen during the encircling period after 88 yr of the 2029 encounter. [ABSTRACT FROM AUTHOR]

The asteroid 99942 Apophis is a Near Earth Asteroid, which was just recently removed from the Potentially Hazardous Asteroids list, since there is no risk of collision with the Earth for the next 100 years. Although, its importance to dynamical astronomy remains evidenced due to other further close encounters that will happen. In the current work, we analyze the dynamics of a hypothetical disc with massless particles around Apophis that produce a complex structure in terms of possible fates (survivors, collisions, and ejections). The gravitational potential due to the highly irregular shape of Apophis produces asymmetries in the dynamics around it. Commensurabilities between the particle's orbital motion frequencies and Apophis' spin generate resonances that dominate the observed complex structure. The results show that the orbital evolution in the third dimension is affected by a combination of the resonances and the gravitational field elongated asymmetry, which helps explain most structure details. [ABSTRACT FROM AUTHOR]

The aim of this work is to verify the stability of the proposed orbital solutions for the third moonlet (Delta) taking into account a realistic gravitational potential for the central body of the quadruple system (Alpha). We also aim to estimate the location and size of a stability region inside the orbit of Gamma. First, we created a set of test particles with intervals of semimajor axis, eccentricities, and inclinations that covers the region interior to the orbit of Gamma, including the proposed orbit of Delta and a wide region around it. We considered three different models for the gravitational potential of Alpha: irregular polyhedron, ellipsoidal body, and oblate body. For a second scenario, Delta was considered a massive spherical body and Alpha an irregular polyhedron. Beta and Gamma were assumed as spherical massive bodies in both scenarios. The simulations showed that a large region of space is almost fully stable only when Alpha was modelled simply as an oblate body. For the scenario with Delta as a massive body, the results did not change from those as mass-less particles. Beta and Gamma do not play any relevant role in the dynamics of particles interior to the orbit of Gamma. Delta's predicted orbital elements are fully unstable and far from the nearest stable region. The primary instability source is Alpha's elongated shape. Therefore, in the determination of the orbital elements of Delta, it must be taken into account the gravitational potential of Alpha assuming, at least, an ellipsoidal shape. [ABSTRACT FROM AUTHOR]

Background: ESR1 mutations have been identified as mechanism for endocrine resistance and are also associated with a decreased overall survival. We assessed ESR1 mutations in circulating tumor DNA (ctDNA) for impact on outcome to taxane-based chemotherapy in advanced breast cancer patients. Methods: ESR1 mutations were determined in archived plasma samples from patients treated with paclitaxel and bevacizumab (AT arm, N = 91) in the randomized phase II ATX study. Samples collected at baseline (n = 51) and at cycle 2 (n = 13, C2) were analyzed using a breast cancer next-generation sequencing panel. This study was powered to detect a benefit in progression-free survival (PFS) at six months for patients treated with paclitaxel/bevacizumab compared to historical trials with fulvestrant. PFS, overall survival (OS), and ctDNA dynamics were exploratory analyses. Results: PFS at six months was 86% (18/21) in patients with an ESR1 mutation detected and 85% (23/27) in wildtype ESR1 patients. In our exploratory analysis, median progression-free survival (PFS) was 8.2 months [95% CI, 7.6–8.8] for ESR1 mutant patients versus 8.7 months [95% confidence interval (CI), 8.3–9.2] for ESR1 wildtype patients [p = 0.47]. The median overall survival (OS) was 20.7 months [95% CI, 6.6–33.7] for ESR1 mutant patients versus 28.1 months [95% confidence interval (CI), 19.3–36.9] for ESR1 wildtype patients [p = 0.27]. Patients with ≥ two ESR1 mutations had a significantly worse OS, but not PFS, compared to those who did not [p = 0.003]. Change in ctDNA level at C2 was not different between ESR1 and other mutations. Conclusions: Presence of ESR1 mutations in baseline ctDNA might not be associated with inferior PFS and OS in advanced breast cancer patients treated with paclitaxel/bevacizumab. [ABSTRACT FROM AUTHOR]

Exomoons are a missing piece of exoplanetary science. Recently, two promising candidates were proposed, Kepler-1625 b-I and Kepler-1708 b-I. While the latter still lacks a dynamical analysis of its stability, Kepler-1625 b-I has already been the subject of several studies regarding its stability and origin. Moreover, previous works have shown that this satellite system could harbour at least two stable massive moons. Motivated by these results, we explored the stability of co-orbital exomoons using the candidates Kepler-1625 b-I and Kepler-1708 b-I as case studies. To do so, we performed numerical simulations of systems composed of the star, planet, and the co-orbital pair formed by the proposed candidates and another massive body. For the additional satellite, we varied its mass and size from a Mars-like to the case where both satellites have the same physical characteristics. We investigated the co-orbital region around the Lagrangian equilibrium point L 4 of the system, setting the orbital separation between the satellites from θmin = 30° to θmax = 90°. Our results show that stability islands are possible in the co-orbital region of Kepler-1708 b-I as a function of the co-orbital companion's mass and angular separation. Also, we identified that resonances of librational frequencies, especially the 2:1 resonance, can constrain the mass of the co-orbital companion. On the other hand, we found that the proximity between the host planet and the star makes the co-orbital region around Kepler-1625 b-I unstable for a massive companion. Finally, we provide TTV profiles for a planet orbited by co-orbital exomoons. [ABSTRACT FROM AUTHOR]

The first proposed Brazilian mission to deep space, the ASTER mission, has the triple asteroid system (153591) 2001 SN263 as a target. One of the mission's main goals is to analyse the physical and dynamical structures of the system to understand its origin and evolution. This work aims to analyse how the asteroid's irregular shape interferes with the stability around the system. The results show that the irregular shape of the bodies plays an important role in the dynamics nearby the system. For instance, the perturbation due to the (153591) 2001 SN263 Alpha's shape affects the stability in the (153591) 2001 SN263 Gamma's vicinity. Similarly, the (153591) 2001 SN263 Beta's irregularity causes a significant instability in its nearby environment. As expected, the prograde case is the most unstable, while the retrograde scenario presents more stability. Additionally, we investigate how the solar radiation pressure perturbs particles of different sizes orbiting the triple system. We found that particles with a 10–50 cm radius could survive the radiation pressure for the retrograde case. Meanwhile, to resist solar radiation, the particles in prograde orbit must be larger than the particles in retrograde orbits, at least one order of magnitude. [ABSTRACT FROM AUTHOR]

Since it was proposed, the exomoon candidate Kepler-1625 b-I has changed the way we see satellite systems. Because of its unusual physical characteristics, many questions about the stability and origin of this candidate have been raised. Currently, we have enough theoretical studies to show that if Kepler-1625 b-I is indeed confirmed, it will be stable. Regarding its origin, previous works indicated that the most likely scenario is capture, although conditions for in situ formation have also been investigated. In this work, we assume that Kepler-1625 b-I is an exomoon and study the possibility of an additional, massive exomoon being stable in the same system. To model this scenario, we perform N -body simulations of a system including the planet, Kepler-1625 b-I, and one extra Earth-like satellite. Based on previous results, the satellites in our system will be exposed to tidal interactions with the planet and to gravitational effects owing to the rotation of the planet. We find that the satellite system around Kepler-1625 b is capable of harbouring two massive satellites. The extra Earth-like satellite can be stable in various locations between the planet and Kepler-1625 b-I, with a preference for regions inside |$25\, R_{\rm p}$|⁠. Our results suggest that the strong tidal interaction between the planet and the satellites is an important mechanism to ensure the stability of satellites in circular orbits closer to the planet, while the 2:1 mean motion resonance between the Earth-like satellite and Kepler-1625 b-I would provide stability for satellites in wider orbits. [ABSTRACT FROM AUTHOR]

The 99942 Apophis close encounter with Earth in 2029 may provide information about asteroid's physical characteristics and measurements of Earth's effects on the asteroid surface. In this work, we analysed the surface and the nearby dynamics of Apophis. The possible effects of its 2029 encounter on the surface and environment vicinity are also analysed. We consider a 340 m polyhedron with a uniform density (1.29, 2.2, and 3.5 g cm−3). The slope angles are computed, as well their variation that arises during the close approach. Such variation reaches 4° when low densities are used in our simulations and reaches 2° when the density is high. The zero-velocity curves, the equilibrium points, and their topological classification are obtained. We found four external equilibrium points and two of them are linearly stable. We also perform numerical simulations of bodies orbiting the asteroid, taking into account the irregular gravitational field of Apophis and two extra scenarios of perturbations: the solar radiation pressure and the Earth's perturbation during the close approach. The radiation pressure plays an important role in the vicinity of the asteroid, only cm-sized particles survived for the time of integration. For densities of 2.2 and 3.5 g cm−3, a region of 5 cm radius particles survived for 30 yr of the simulation, and for 1.29 g cm−3, only particles with 15 cm of radius survived. The ejections and collisions are about 30–50 times larger when the close encounter effect is added but around 56–59 per cent of particles still survive the encounter. [ABSTRACT FROM AUTHOR]

Didymos and Dimorphos are primary and secondary, respectively, asteroids who compose a binary system that make up the set of Near Earth Asteroids (NEAs). They are targets of the Double Asteroid Redirection Test (DART), the first test mission dedicated to study of planetary defense, for which the main goal is to measure the changes caused after the secondary body is hit by a kinect impactor. The present work intends to conduct a study, through numerical integrations, on the dynamics of massless particles distributed in the vicinity of the two bodies. An approximate shape for the primary body was considered as a model of mass concentrations (mascons) and the secondary was considered as a massive point. Our results show the location and size of stable regions, and also their lifetime. [ABSTRACT FROM AUTHOR]

The (153591) 2001 SN263 asteroid system, a target of the first Brazilian interplanetary space mission, is one of the known three triple systems within the population of near-Earth asteroids. One of the mission objectives is to collect data about the formation of this system. The analysis of these data will help in the investigation of the physical and dynamical structures of the components (Alpha, Beta, and Gamma) of this system, in order to find vestiges related to its origin. In this work, we assume the irregular shape of the 2001 SN263 system components as uniform-density polyhedra and computationally investigate the gravitational field generated by these bodies. The goal is to explore the dynamical characteristics of the surface and environment around each component. Then, taking into account the rotational speed, we analyse their topographic features through the quantities geometric altitude, tilt, geopotential, slope, and surface accelerations among others. Additionally, the investigation of the environment around the bodies made it possible to construct zero-velocity curves, which delimit the location of equilibrium points. The Alpha component has a peculiar number of 12 equilibrium points, all of them located very close to its surface. In the cases of Beta and Gamma, we found four equilibrium points not so close to their surfaces. Then, performing numerical experiments around their equilibrium points, we identified the location and size of just one stable region, which is associated with an equilibrium point around Beta. Finally, we integrated a spherical cloud of particles around Alpha and identified the location on the surface of Alpha where the particles have fallen. [ABSTRACT FROM AUTHOR]

Radar observations show that (16) Psyche is one of the largest and most massive asteroids of the M-class located in the main belt, with a diameter of approximately 230 km. This fact makes Psyche a unique object since observations indicated an iron-nickel composition. It is believed that this body may be what was left of a metal core of an early planet that would have been fragmented over millions of years due to violent collisions. In this work, we study a variety of dynamical aspects related to the surface, as well as, the environment around this asteroid. We use computational tools to explore the gravitational field generated by this body, assuming constant values for its density and rotation period. We then determine a set of physical and dynamical characteristics over its entire surface. The results include the geometric altitude, geopotential altitude, tilt, slope, among others. We also explore the neighborhood around the asteroid (16) Psyche, so that the location and linear stability of the equilibrium points were found. We found four external equilibrium points, two of them linearly stable. We confirmed the stability of these points by performing numerical simulations of massless particles around the asteroid, which also showed an asymmetry in the size of the stable regions. In addition, we integrate a cloud of particles in the vicinity of (16) Psyche in order to verify in which regions of its surface the particles are most likely to collide. [ABSTRACT FROM AUTHOR]

Interestingly, 80% of ST2/BN2 patients reached an early molecular response (EMR) and the 2 ST2/BN2 patients who did not achieve an EMR after 1 cycle of therapy are still in complete remission. Also in the validation cohort, patients with <2.5Log SB 10 sb hGE and/or assigned to cluster BN2 and ST2 presented an excellent outcome with a 40-month PFS and OS of 73.2% and 79.7%, compared to 39.2% and 44.8% for other patients, respectively (both I p i = 0.001) (Figure 1B). B Introduction: b The quantification of circulating tumor DNA (ctDNA) on the liquid biopsy at the time of diagnosis allows to stratify the outcome of diffuse large B-cell lymphoma (DLBCL) patients but its integration with molecular clustering has not been evaluated so far. [Extracted from the article]

The recently discovered ring around the dwarf planet (136108) Haumea is located near the 1:3 resonance between the orbital motion of the ring particles and the spin of Haumea. In the current work, we study the dynamics of individual particles in the region where the ring is located. Using the Poincaré surface of section technique, the islands of stability associated with the 1:3 resonance are identified and studied. Throughout its existence, this resonance is shown to be doubled, producing pairs of periodic and quasi-periodic orbits. The fact of being doubled introduces a separatrix, which generates a chaotic layer that reduces the size of the stable regions of the 1:3 resonance significantly. The results also show that there is a minimum equivalent eccentricity (e 1 |$\colon$| 3) required for the existence of such a resonance. This value seems to be too high to keep a particle within the borders of the ring. On the other hand, the Poincaré surface of sections shows the existence of much larger stable regions, but associated with a family of first-kind periodic orbits. They exist with equivalent eccentricity values lower than e 1 |$\colon$| 3, covering a large radial distance, which encompasses the region of Haumea's ring. Therefore, this analysis suggests that Haumea's ring is in a stable region associated with a first-kind periodic orbit instead of the 1:3 resonance. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effects of pasture allowances on forage production, milk yield and composition, and grazing behaviour of Holstein cows during autumn. Thirty-six Holstein cows calving in the autumn were allocated to blocks considering: calving date, bodyweight, and body score. Treatments consisted of three pasture allowances as follows: high (HA; 38.4 kg DM/cow.day), medium (MA; 30.3 kg DM/cow.day), and low (LA; 26.8 kg DM/cow.day) pasture allowances. Forage mass and forage height pre-grazing were similar (P > 0.05) for all grazing targets. Pasture-use efficiency was affected (P < 0.05) by the pasture allowance. The highest and lowest efficiency was obtained with treatments LA and HA, respectively. The neutral detergent fibre content of forage harvesting was affected (P < 0.05) by the pasture allowance, with average of 44.8, 47.0, and 49.4 to HA, MA, and LA, respectively. There was an effect of pasture allowances (P < 0.05) on the milk yield per hectare and milk yield per cow. The highest production was observed in LA (438 L/ha.day) and the lowest in HA (314 L/ha.day). The percentage of milk fat, milk protein, and milk fat (g/cow.day) did not differ (P > 0.05) among pasture allowances. There was effect (P < 0.05) of pasture allowance with higher grazing time (369 min) and lower rumination time (23.3 min) observed to HA. Pasture allowances affected (P < 0.05) the total number of bites/day and bites/min, but did not affect (P > 0.05) bite mass. The pasture managements with low (26.8 kg DM/cow.day) pasture allowances provided better conditions for milk yield per area, likely due to the better grazing efficiency. However, pasture allowance provide little measurable changes on grazing behaviour. This experiment deals with grazing management effects on milk production and grazing behaviour of dairy cows, which is an area of interest to those involved in pasture-based dairy industries. This study aimed to evaluate the effects of pasture allowances on forage production, milk yield and composition, and grazing behaviour, so that the pasture managements with low pasture allowances provided better conditions for milk yield per area and provide little measurable changes on grazing behaviour. Thus, farmers may increase stocking rate to reach higher milk production when lactating dairy cows graze mixed pasture swards. However, the impact of higher stocking rates on the persistence of pasture species needs to be investigated. [ABSTRACT FROM AUTHOR]

The technique of mutual approximations accurately gives the central instant of the maximum apparent approximation of two moving natural satellites in the plane of the sky. This can be used in ephemeris fitting to infer the relative positions of satellites with high precision. Only mutual phenomena – occultations and eclipses – can achieve better results. However, mutual phenomena only occur every six years in the case of Jupiter. Mutual approximations do not have this restriction and can be observed at any time in the year as long as the satellites are visible. In this work, we present 104 central instants determined from the observations of 66 mutual approximations between the Galilean moons carried out at different sites in Brazil and France during the period 2016–2018. For 28 events, we have at least two independent observations. All telescopes were equipped with a narrow-band filter centred at 889 nm with a width of 15 nm to eliminate the scattered light from Jupiter. The telescope apertures ranged between 25 and 120 cm. For comparison, the precision of the positions obtained with classical CCD astrometry is about 100 mas, for mutual phenomena it can be 10 mas or less, and the average internal precision obtained with mutual approximations is 11.3 mas. This new type of simple, yet accurate, observations can significantly improve the orbits and ephemeris of Galilean satellites and thus it can be very useful for the planning of future space missions to the Jovian system. [ABSTRACT FROM AUTHOR]

In this paper, analytical attitude propagators for spin-stabilized satellites are analyzed. For this purpose, external torques are introduced in the motion equations such as solar radiation pressure torque, aerodynamic torque, gravity gradient torque, and magnetic residual and eddy current torques. For the magnetic torques, it used both the dipole and quadripole Earth's magnetic field models. The obtained analytical solution is applied and compared with actual data for Brazilian data collection satellites SCD1 and SCD2. The results, when a daily data update is applied, based on the INPE-Brazilian Institute for Space Research supplied data, show a good agreement of all involved parameters with the actual deviations in the parameter values within the precision required for the satellite mission. This permits to conclude that the used theory is suitable for the studied problem. Thus, the propagators presented in this work can be applied to predict the rotational motion of spin-stabilized artificial satellites, particularly for SCD1 and SCD2 satellites over the considered time period. [ABSTRACT FROM AUTHOR]

Purpose: To diagnose cholesteatoma when it is not visible through tympanic perforation, imaging techniques are necessary. Recently, the combination of computed tomography and magnetic resonance imaging has proven effective to diagnose middle ear cholesteatoma. In particular, diffusion weighted images have integrated the conventional imaging for the qualitative assessment of cholesteatoma. Accordingly, the aim of this study was to obtain a quantitative analysis of cholesteatoma calculating the apparent diffusion coefficient value. So, we investigated whether it could differentiate cholesteatoma from other inflammatory tissues both in a preoperative and in a postoperative study.Methods: This study included 109 patients with clinical suspicion of primary or residual/recurrent cholesteatoma. All patients underwent preoperative computed tomography and magnetic resonance imaging with diffusion sequences before primary or second-look surgery to calculate the apparent diffusion coefficient value.Results: We found that the apparent diffusion coefficient values of cholesteatoma were significantly lower than those of non cholesteatoma. In particular, the apparent diffusion coefficient median value of the cholesteatoma group (0.84 × 10− 3 mm2/s) differed from the inflammatory granulation tissue (2.21 × 10− 3 mm2/s) group (p < 2.2 × 10− 16). Furthermore, we modeled the probability of cholesteatoma by means of a logistic regression and we determined an optimal cut-off probability value of ~ 0.86 (specificity = 1.0, sensitivity = 0.97), corresponding to an apparent diffusion coefficient cut-off value of 1.37 × 10− 3 mm2/s.Conclusions: Our study has demonstrated that apparent diffusion coefficient values constitute a valuable quantitative parameter for preoperative differentiation of cholesteatomas from other middle ear inflammatory diseases and for postoperative diagnosis of recurrent/residual cholesteatomas. [ABSTRACT FROM AUTHOR]

Previous literature has highlighted the mechanisms of molecular toxicity induced by substances such as arsenic, cadmium, chromium, nickel, lead, barium and PCBs. The research was carried out on 20 volunteers, all the patients gave their consent to the research: the aim of the study was to evaluate the presence of metals and PCBs in these different matrices (blood and hair), correlating the biochemical data to pathological conditions present, and also to the area in which patients resided. Various quantitative determinations were carried out on samples of blood and hair for 14 heavy metals and on blood samples for 12 PCBs. For the 11 patients the results indicated that blood levels for half of the 14 displayed heavy metals measured considerably higher compared to the reference values, whilst the levels measured in hair evidenced some positive values significantly higher than the maximum reference. Of the 12 PCBs assayed in blood some showed higher positive values compared to the maximum tabular reference (although there is no clear reference quantified in theWHO-2005 report). In the 9 healthy patients heavy metals in the blood were within the expected target range, with those showing positive results (≤ 3 out of 14 heavy metals for each patient) having values only slightly higher than the reference maximum. The levels of 14 heavy metals measured in hair were below thresholds, and levels for the 12 PCBs measured in blood showed negativity or positivity with values close to the minimum benchmarks. The analyses carried out on biological matrices have uncovered important and significant differences between healthy and unhealthy subjects, both qualitative and quantitative differences with respect to heavy metals and PCBs. All patients with head and neck cancer enlisted for the study had heavy metal and PCB blood levels at least twice the maximum reference level. The levels of heavy metals in hair were at least double the maximum reference. In contrast, all healthy volunteers enrolled showed no significant levels for either metals or PCBs. [ABSTRACT FROM AUTHOR]

In general, small bodies of the Solar system, e.g. asteroids and comets, have a very irregular shape. This feature affects significantly the gravitational potential around these irregular bodies, which hinders dynamical studies. The Poincaré surface of section technique is often used to look for stable and chaotic regions in two-dimensional dynamic cases. In this work, we show that this tool can be useful for exploring the surroundings of irregular bodies such as the asteroid 4179 Toutatis. Considering a rotating system with a particle, under the effect of the gravitational field computed three dimensionally, we define a plane in the phase space to build the Poincaré surface of section. Despite the extra dimension, the sections created allow us to find trajectories and classify their stabilities. Thus, we have also been able to map stable and chaotic regions, as well as to find correlations between those regions and the contribution of the third dimension of the system to the trajectory dynamics as well. As examples, we show details of periodic (resonant or not) and quasi-periodic trajectories. [ABSTRACT FROM AUTHOR]

This paper presents the comparison between the numerical and analytical results of a spacecraft attitude propagation for a spin-stabilized satellite. Some external torques are introduced in the equations of the motion and the comparisons are done considering that these torques are acting together, which are: gravity gradient, aerodynamic, solar radiation, magnetic residual and eddy current. In the numerical approach it is used the quaternion to represent the attitude. This numerical approach can be applied for any kind of satellite. The analytical approach is applied directly for a spin-stabilized satellite and the equations of motion are described in terms of the spin velocity, spin axis right ascension and declination angles. An analytical solution of these equations is presented and valid for one orbit period. Applications are developed considering the Brazilian spin-stabilized satellites SCD1 and SCD2. The comparisons are important to validate some simplifications that are required in the analytical approach. The results show that the average components of the external torque are sufficient to observe the main influence of the considered torques. [ABSTRACT FROM AUTHOR]