Resonantly-forced Eccentric Ringlets: Relationships between Surface Density, Resonance location, Eccentricity and Eccentricity-gradient

We use a simple model of the dynamics of a narrow-eccentric ring, to put some constraints on some of the observable properties of the real systems.In this work we concentrate on the case of the `Titan ringlet of Saturn'.Our approach is fluid-like, since our description is based on normal modes of oscillation rather than in individual particle orbits. Thus, the rigid precession of the ring is described as a global $m=1$ mode, which originates from a standing wave superposed on an axisymmetric background. An integral balance condition for the maintenance of the $m=1$ standing-wave can be set up, in which the differential precession induced by the oblateness of the central planet must cancel the contributions of self-gravity, the resonant satellite forcing and collisional effects. We expect that in nearly-circular narrow rings dominated by self-gravity, the eccentricity varies linearly across the ring. Thus, we take a first order expansion and we derive two integral relationships from the rigid-precession condition. These relate the surface density of the ring with the eccentricity at the center, the eccentricity gradient and the location of the secular resonance. These relationships are applied to the Titan ringlet of Saturn, which has a secular resonance with the satellite Titan in which the ring precession period is close to Titan's orbital period. In this case, we estimate the mean surface density and the location of the secular resonance.Comment: Accepted for publication in Celestial Mechanics and Dynamical Astronom

Migration and the formation of systems of hot super-Earths and Neptunes

The existence of extrasolar planets with short orbital periods suggests that planetary migration induced by tidal interaction with the protoplanetary disk is important. Cores and terrestrial planets may undergo migration as they form. In this paper we investigate the evolution of a population of cores with initial masses in the range 0.1-1 earth mass embedded in a disk. Mutual interactions lead to orbit crossing and mergers, so that the cores grow during their evolution. Interaction with the disk leads to orbital migration, which results in the cores capturing each other in mean motion resonances. As the cores migrate inside the disk inner edge, scatterings and mergers of planets on unstable orbits together with orbital circularization causes strict commensurability to be lost. Near commensurability however is usually maintained. All the simulations end with a population of typically between two and five planets, with masses depending on the initial mass. These results indicate that if hot super-Earths or Neptunes form by mergers of inwardly migrating cores, then such planets are most likely not isolated. We would expect to always find at least one, more likely a few, companions on close and often near-commensurable orbits. To test this hypothesis, it would be of interest to look for planets of a few to about 10 earth masses in systems where hot super-Earths or Neptunes have already been found.Comment: 29 pages, to be published in Ap

Gynecomastia and Chest Masculinization: An Updated Comprehensive Reconstructive Algorithm

Background: Gynecomastia is a common finding in males. Clinical aspect varies widely in world populations showing peculiar hallmarks according to different body shapes reflecting personal expectations; therefore, a surgical plan must be tailored on individual basis to all type of patients. Materials and Method: A total of 522 patients, treated for bilateral gynecomastia from January 2007 to January 2019, were included and reviewed in this retrospective study. Considering physical status BMI, muscular trophism, hypertrophy of the mammary region, nipple–areola disorder, gland and skin cover consistency, a four-tier classification system has been used to classify the deformity and to assess a surgical plan. In all cases, a subcutaneous mastectomy was performed under direct vision. Results: No recurrence of the deformity was observed as well as major complications such as necrosis, and high level of satisfaction was observed in all groups. No breast cancer was found at the histological examinations Operative time ranged from 25 minutes up to 120 minutes and hospitalization time ranged from 1 to 3 days. Conclusion: Since the physical status is strictly related to the clinical features of the disorder, a comprehensive classification system and a reconstructive algorithm are proposed. Level of Evidence IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/0026

Apse-alignment in narrow-eccentric ringlets and its implications for the EPSILON-ring of Uranus and the ring system of (10199) Chariklo

The discovery of ring systems around objects of the outer Solar System provides a strong motivation to apply theoretical models in order to better estimate their physical and orbital parameters, which can constrain scenarios for their origin. We review the criterion for maintaining apse-alignment across a ring and the balance between the energy input rate provided by a close by satellite and the internal dissipation rate occurring through ring particle collisions that is required to maintain ring eccentricity, as derived from the equations of motion governing the Lagrangian-displacements of the ring-particle orbits. We use the case of the epsilon-ring of Uranus, to calibrate our theoretical discussion and illustrate the basic dynamics governing these types of ring. In the case of the ring system of (10199) Chariklo, where the evidence that the rings are eccentric is not conclusive, we apply the theory of apse-alignment to derive information about the most plausible combination of values of the surface density and eccentricity-gradient, as well as the masses and locations of their postulated but -presently undetected-shepherd-satellites. When the balance conditions that we predict are applied to the ring system of (10199) Chariklo, we are able to estimate the minimum mass of a shepherd satellite required to prevent eccentricity decay, as a function of its orbital location, for two different models of dissipation. We conclude that the satellite mass required to maintain the m = 1 eccentric mode in the ring, would be similar or smaller than that needed to confine the rings radially.Comment: In press in ICARU

Photometry of the Oort Cloud comet C/2009 P1(Garradd): pre-perihelion observations at 5.7 and 2.5 AU

The aim of this paper is to contribute to the characterization of the general properties of the Long Period Comets (LPCs) family, and in particular to report on the dust environment of comet C/2009 P1 (Garradd). The comet was observed at two epochs pre-perihelion, at ~6 AU and at ~2.5 AU: broad-band images have been used to investigate its coma morphology and properties and to model the dust production rate. Comet C/2009 P1 (Garradd) is one of the most active and “dust producing” LPCs ever observed, even at the large heliocentric distance rh~6 AU. Its coma presents a complex morphology, with subtle structures underlying the classical fan-shaped tail, and, at rh~2.5 AU, also jet-like structures and spiralling outflows. In the reference aperture of radius ρ=5°×104 km, the R-Afρ is 3693±156 cm and 6368±412 cm, in August 2010 (rh~6 AU) and July 2011 (rh~2.5 AU), respectively. The application of a first order photometric model, under realistic assumptions on grain geometric albedo, power-law dust size distribution, phase darkening function and grain dust outflow velocity, yielded a measure of the dust production rate for the two epochs of observation of Qd=7.27×102 kg/s and Qd=1.37×103 kg/s, respectively, for a reference outflow dust velocity of vsmall=25 m/s for small (0.1–10 µm) grains and vlarge=1 m/s for large (10 µm–1 cm) grains. These results suggest that comet Garradd is one of the most active minor bodies observed in recent years, highly contributing to the continuous replenishment of the Interplanetary Dust Complex also in the outer Solar System, and pose important constraints on the mechanism(s) driving the cometary activity at large heliocentric distances

Balanced Scorecard sebagai Pengukuran Kinerja Koperasi Perikanan Segaraning Harum Kabupaten Badung

The Balanced scorecard is used to measure performance by observing the balance between financial and non financial side between short term and long term as well as involving the internal and external factors. The cooperative as a business entity is expected to implement the balanced scorecard to achieve the vision and mission of cooperation and improving the performance of cooperatives. The purpose of this research was to analyze the application of the four elements of the balanced scorecard which is expected to create cooperatives to compete with other economic institutions. This research was conducted with descriptive method to describe the application of the balanced scorecard element for a month in the Save unit borrow Cooperative Fisheries Segaraning Harum. The results showed the application of elements of a financial perspective using the current ratio, total assets to debt ratio rated very unhealthy and return on asset were judged enough healthy. Application of the elements of the perspective of customers using the level of customer satisfaction rated satisfied customer retention rate and are rated good. Application of the elements of the internal business processes perspective measured using Manufacturing Cycle Efficiency (MCE), namely the process of transaction deposits and loans rated has been running efficiently. Application of the elements of the learning and growth perspective employees using employee satisfaction level of votes satisfied the employee retention rate and are rated good Suggestionsfrom this researchthat thebalanced scorecardelementscan not only beusedas a measureof performancein theSegaraningHarumCooperative Fisheriesbutalsoas a strategy ofthe cooperative.Balancedscorecardshould begin tobe appliedas a measureof performanceineach ofthe cooperativein order to competewithother economicinstitutions. Apart fromcooperatives,the governmentis expected toissue a policythatbalanced scorecardused asa strategyrequired to beimplementedby the cooperative

A BRIEF DISSECTION GUIDE TO HUMAN THORAX

The purpose of this technical report is to present that, in summer 2018, a group of students from the University of Palermo did at the University of malta. The students have the experience to dissected a thorax under a guide to expert dissectors. This work would be also a small dissection guide for young students who want to learn the main bases of dissectio

Evolutionary Dynamics While Trapped in Resonance: A Keplerian Binary System Perturbed by Gravitational Radiation

The method of averaging is used to investigate the phenomenon of capture into resonance for a model that describes a Keplerian binary system influenced by radiation damping and external normally incident periodic gravitational radiation. The dynamical evolution of the binary orbit while trapped in resonance is elucidated using the second order partially averaged system. This method provides a theoretical framework that can be used to explain the main evolutionary dynamics of a physical system that has been trapped in resonance.Comment: REVTEX Style, Submitte