scholarly journals Orbital Dynamics and the Evolution of Planetary Habitability in the AU Mic System

2021 ◽  
Vol 163 (1) ◽  
pp. 20
Author(s):  
Stephen R. Kane ◽  
Bradford J. Foley ◽  
Michelle L. Hill ◽  
Cayman T. Unterborn ◽  
Thomas Barclay ◽  
...  
Keyword(s):  
Initial Conditions ◽  
Planetary Systems ◽  
Transitional Period ◽  
Dynamical Analysis ◽  
Habitable Zone ◽  
Long Term Stability ◽  
Formation And Evolution ◽  
Planetary Habitability

Abstract The diverse planetary systems that have been discovered are revealing the plethora of possible architectures, providing insights into planet formation and evolution. They also increase our understanding of system parameters that may affect planetary habitability, and how such conditions are influenced by initial conditions. The AU Mic system is unique among known planetary systems in that it is a nearby, young, multiplanet transiting system. Such a young and well-characterized system provides an opportunity for orbital dynamical and habitability studies for planets in the very early stages of their evolution. Here, we calculate the evolution of the Habitable Zone of the system through time, including the pre-main-sequence phase that the system currently resides in. We discuss the planetary atmospheric processes occurring for an Earth-mass planet during this transitional period, and provide calculations of the climate state convergence age for both volatile rich and poor initial conditions. We present results of an orbital dynamical analysis of the AU Mic system that demonstrate the rapid eccentricity evolution of the known planets, and show that terrestrial planets within the Habitable Zone of the system can retain long-term stability. Finally, we discuss follow-up observation prospects, detectability of possible Habitable Zone planets, and how the AU Mic system may be used as a template for studies of planetary habitability evolution.

scholarly journals Long-term orbital stability of exosolar planetary systems with highly eccentric orbits

2015 ◽  
Vol 11 (A29A) ◽  
pp. 38-39
Author(s):  
Kyriaki I. Antoniadou ◽  
George Voyatzis
Keyword(s):  
Phase Space ◽  
Orbital Stability ◽  
Planetary Systems ◽  
Dynamical Analysis ◽  
Hill Stability ◽  
Mean Motion Resonances ◽  
Term Stability ◽  
Long Term Stability ◽  
Eccentric Orbits

AbstractNowadays, many extrasolar planetary systems possessing at least one planet on a highly eccentric orbit have been discovered. In this work, we study the possible long-term stability of such systems. We consider the general three body problem as our model. Highly eccentric orbits are out of the Hill stability regions. However, mean motion resonances can provide phase protection and orbits with long-term stability exist. We construct maps of dynamical stability based on the computation of chaotic indicators and we figure out regions in phase space, where the long-term stability is guaranteed. We focus on regions where at least one planet is highly eccentric and attempt to associate them with the existence of stable periodic orbits. The values of the orbital elements, which are derived from observational data, are often given with very large deviations. Generally, phase space regions of high eccentricities are narrow and thus, our dynamical analysis may restrict considerably the valid domain of the system's location.

Long-Term Stability of Sutured Scleral Fixation of a Posterior Chamber Intraocular Lens With 10-0 Polypropylene for More Than 30 Years

2021 ◽  
pp. 247412642097887
Author(s):  
Gregg T. Kokame ◽  
Tarin T. Tanji ◽  
Jase N. Omizo
Keyword(s):  
Intraocular Lens ◽  
Posterior Chamber ◽  
Scleral Flap ◽  
Scleral Fixation ◽  
Polypropylene Suture ◽  
Long Term Stability ◽  
Posterior Chamber Intraocular Lens ◽  
Polypropylene Sutures

Purpose: We report the longest follow-up to our knowledge of stable scleral fixation of a posterior chamber intraocular lens (PC IOL) with 10-0 polypropylene sutures. Methods: A retrospective review is presented of a case with more than 30 years’ follow-up after performing sutured scleral fixation with 10-0 polypropylene suture using 2 sutures tied together under a scleral flap. One suture was a cow-hitch looped around the haptic, and the other suture was passed through the sclera to create the scleral fixation. Results: The scleral fixation with 10-0 polypropylene suture knots for both haptics of the PC IOL allowed central optic positioning with excellent vision for more than 30 years without suture breakage. Conclusions: Polypropylene sutures for scleral fixation of PC IOLs remained stable for more than 30 years with central positioning of the PC IOL, without exposure of the fixation suture knots through the conjunctiva, and without suture breakage.

Long term stability of the subcutaneous cardioverter defibrillator implanted by means of the intermuscular two incision technique

EP Europace ◽  
2021 ◽  
Vol 23 (Supplement_3) ◽  
Author(s):  
G Bisignani ◽  
A Bisignani ◽  
AL Cavaliere ◽  
M Lovecchio ◽  
S Valsecchi ◽  
...  
Keyword(s):  
Thoracic Wall ◽  
Fat Tissue ◽  
Cardioverter Defibrillator ◽  
Long Term Stability ◽  
Funding Sources ◽  
Incision Technique ◽  
Post Implantation ◽  
Funding Acknowledgements

Abstract Funding Acknowledgements Type of funding sources: None. Background To ensure effective defibrillation with the subcutaneous implantable cardioverter defibrillator (S-ICD), both the lead and the generator must be adequately positioned extrathoracically. We assessed the long-term adequacy of the S-ICD system position and its stability in a group of patients who received the S-ICD by means of the two-incision intermuscular technique. Methods The PRAETORIAN score uses chest radiography to provide feedback on S-ICD positioning, and identifies patients with high defibrillation thresholds. We compared radiographs taken immediately after implantation and on 12-month follow-up examination. Results We analyzed data from 38 patients with the S-ICD generator positioned in an intermuscular pocket. The median PRAETORIAN score was 38 [25th to 75th percentile: 30 to 60]. Two (5%) patients had a score of 90 (intermediate risk of conversion failure). The thickness of the adipose tissue between the coil and the sternum was ≤1 coil width in 72% of patients, the generator was on, or posterior to, the midline in 94% of patients, and the amount of fat tissue between the generator and the thoracic wall was less than the generator width in 78% of patients. No generator or electrode dislodgments were detected on analyzing radiographs collected at the 12-month visit. In all patients, assessment of the PRAETORIAN score confirmed the values calculated on post-implantation analysis. During follow-up, no ineffective therapies, sudden cardiac or device-related deaths occurred. Conclusions The position of the S-ICD system implanted using the two-incision intermuscular technique was adequate at the time of implantation and remained stable after 12 months.

scholarly journals Middle Ear Transducer: Long Term Stability of the Latest Generation T2

2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
Nils Kristian Prenzler ◽  
Eugen Kludt ◽  
Thomas Giere ◽  
Rolf Salcher ◽  
Thomas Lenarz ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Middle Ear ◽  
Observation Time ◽  
Term Stability ◽  
Long Term Stability ◽  
Average Observation ◽  
Technical Failures

Objectives/Hypothesis. Comparing long term stability of the Middle Ear Transducers (MET) of the 1st generation T1 (Otologics LLC) with the current generation T2 (Cochlear Ltd.) in all our clinical cases with standard incus coupling. Study Design. Retrospective chart review. Methods. 52 ears implanted with a MET device between 2008 and 2016 were analyzed retrospectively. All patients suffered from sensorineural hearing loss and the actuator was coupled to the body of the incus (standard coupling). 23 ears were implanted with the transducer T1 (Otologics LLC) between 2008 and 2011 and 29 ears were implanted with the current transducer T2 since 2011 (Otologics LLC/Cochlear Ltd.). Latest available in situ and bone conduction (BC) thresholds were exploited for a follow-up period of up to 7 years after first fitting. Long term stability of coupling and actuator performance was evaluated by tracking differences between in situ and BC thresholds. Results. In the T1 group, 9 out of 23 implants were still used by the patients at their last follow-up visit (average observation time 3.7 yrs.; min 1.0 yrs., max 7.4 yrs.). In 9 patients a technical failure identified by a decrease of in situ threshold of more than 15 dB compared to BC thresholds [Δ (in situ – BC)] lead to non-usage of the implant and 7 explantations. Five other explantations occurred due to medical reasons such as BC threshold decrease, infection, or insufficient speech intelligibility with the device. In the T2 group, 23 out of 29 implants were still used at the most current follow-up visit (average observation time 3.3 yrs.; min 1.0 yrs., max 4.8 yrs.). No technical failures were observed up to more than 4 years after implantation. Five T2 patients discontinued using the device due to insufficient benefit; two of these patients were explanted. One patient had to be explanted before the activation of the device due to disorders of wound healing. Nevertheless, a small but significant decrease of hearing loss corrected coupling efficiency [Δ (in situ – BC)] was seen in the T2 group. Conclusions. In contrast to the T1 transducers of the earlier generation of MET systems where technical failures occurred frequently, no technical failures were detected after 29 implantations with the current T2 transducers. However, a small but significant decline of transmission efficiency was observable even in the T2 implanted group.

scholarly journals Combining Techniques to Treat Isolated Deep Recession-Type Defects: A Case Report with Long-Term Stability

2021 ◽  
Vol 2021 ◽  
pp. 1-5
Author(s):  
João Carnio ◽  
Anna Tereza Carnio
Keyword(s):  
Case Report ◽  
Root Coverage ◽  
Case Presentation ◽  
Term Stability ◽  
Long Term Stability ◽  
Dental Procedures ◽  
Donor Area ◽  
Deep Recession

Introduction. The purpose of this case report was to show the clinical long-term stability of a successful two-step root coverage procedure. A combination of two single techniques was used to treat an isolated deep-wide defect. Case Presentation. A 28-year-old female patient was referred in order to treat a single recession defect at #22. Due to her fear of dental procedures and a poor economic situation, the team developed an alternative solution. They used a modified apically repositioned flap (MARF) to increase the donor area and then a laterally positioned flap (LPF) to treat the root defect. Clinical evaluation at the three-year follow-up revealed complete resolution of the defect, a gain in clinical attachment, excellent esthetic results, and minor morbidity to the patient. Conclusion. The combination of the MARF and the LPF procedures was able to successfully treat a single deep recession defect with some advantages over traditional techniques such as simplicity, ideal color match of tissues, and the absence of palatal donor tissue.

scholarly journals Close encounters with the Death Star: Interactions between collapsed bodies and the Solar System

2021 ◽  
Vol 648 ◽  
pp. L2 ◽  
Author(s):  
Václav Pavlík ◽  
Steven N. Shore
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Solar System ◽  
Planetary System ◽  
Planetary Systems ◽  
Symplectic Integrator ◽  
Orbital Parameters ◽  
Long Term Stability ◽  
Complete Disruption

Aims. We aim to investigate the consequences of a fast massive stellar remnant – a black hole (BH) or a neutron star (NS) – encountering a planetary system. Methods. We modelled a close encounter between the actual Solar System (SS) and a 2 M⊙ NS and a 10 M⊙ BH, using a few-body symplectic integrator. We used a range of impact parameters, orbital phases at the start of the simulation derived from the current SS orbital parameters, encounter velocities, and incidence angles relative to the plane of the SS. Results. We give the distribution of possible outcomes, such as when the SS remains bound, when it suffers a partial or complete disruption, and in which cases the intruder is able to capture one or more planets, yielding planetary systems around a BH or a NS. We also show examples of the long-term stability of the captured planetary systems.

scholarly journals Therapeutic Challenges for Elderly Patients with Primary Hyperparathyroidism

2019 ◽  
Vol 2019 ◽  
pp. 1-3 ◽  
Author(s):  
Kenneth Sluis ◽  
Hyon Kim ◽  
Yuling He ◽  
Beatrice Wong ◽  
Xiangbing Wang
Keyword(s):  
Primary Hyperparathyroidism ◽  
Chart Review ◽  
Treatment Options ◽  
Case Series ◽  
Retrospective Chart Review ◽  
Long Term Stability ◽  
Feasible Option ◽  
One Year

Primary hyperparathyroidism (PHPT) predominantly affects older adults, and parathyroidectomy can achieve definitive cure in symptomatic PHPT and asymptomatic meeting surgical criteria. As the population continues to age, the treatment of PHPT in octogenarians and nonagenarians presents a clinical conundrum. This case series presents the management of eight patients 85 years of age and older diagnosed with PHPT. A retrospective chart review of patients diagnosed with primary hyperparathyroidism were identified in a single institution. Those patients 85 years of age and older who were followed up for over one year were included in this case series. The literature on treatment options for this age group was also reviewed. Eight cases of PHPT patients aged 88 ± 2.5 years old with a follow-up average of 5.6 ± 4.4 years were reported in our case series. Six PHPT patients were medically managed and two PHPT patients underwent parathyroid resection. Most of the medically managed PHPT patients except for one had long-term stability of disease for over five years. The treatment of PHPT diagnosed in patients over 85 years of age presents a clinical challenge for which there is no clear consensus guideline. Our case series supports that medical therapy is a feasible option for PHPT patients over 85 years old.

scholarly journals Resolution of Abfraction-Associated Gingival Fenestration Utilizing Connective Tissue Grafting

2019 ◽  
Vol 2019 ◽  
pp. 1-4
Author(s):  
Braydon Haskell ◽  
J. Kobi Stern ◽  
Jordan Ghiassi ◽  
Andrew Kurialacherry ◽  
Sadja Gaud-Quintana ◽  
...  
Keyword(s):  
Connective Tissue ◽  
Root Surface ◽  
Case Presentation ◽  
Long Term Stability ◽  
Connective Tissue Graft ◽  
Uncertain Etiology ◽  
Noncarious Cervical Lesion ◽  
Oral Soft Tissue

Introduction. Gingival fenestration (GF) is a distinct clinical entity of uncertain etiology that is seldom documented in the literature. It has been associated mainly with submucosal mechanical irritants such as calculus that subsequently create an opening in the oral soft tissue, usually at facial anterior sites. Surgical correction may be indicated to address functional and/or esthetic concerns. Case Presentation. The patient, a 74-year-old male, presented to the clinic with a chief complaint of “something is poking through my gum.” Clinical exam revealed a gingival fenestration on the facial of tooth #11, associated with what appeared to be a pronounced noncarious cervical lesion (NCCL). Surgical treatment consisted of a connective tissue graft and odontoplasty of the sharp protruding edge of the root surface. Healing was uneventful with excellent closure of the fenestration and no evidence of recurrence after 18 months of follow-up. Conclusion. GF is a perforation of the mucosa typically associated with underlying sharp mechanical etiology. This report describes a fenestration that developed from a probable abfractive lesion, which later was successfully closed and exhibits long-term stability.

Treatment of severe mandibular deficiency following TMJ ankyloses by distraction osteogenesis and orthodontic treatment with microimplants

2021 ◽  
pp. 146531252110598
Author(s):  
Ho-Jin Kim ◽  
Hyo-Sang Park
Keyword(s):  
Distraction Osteogenesis ◽  
Term Treatment ◽  
Long Term Stability ◽  
Anterior Teeth ◽  
Mandibular Distraction Osteogenesis ◽  
Long Term Treatment ◽  
History Of ◽  
Mandibular Retrognathia

Severe mandibular deficiency caused by temporomandibular joint (TMJ) ankyloses produces functional and aesthetic problems that require complicated long-term treatment. In this case report, we describe the benefits of using microimplant mechanics for controlling the direction of distraction during distraction osteogenesis and for performing the movement of teeth. We also present its remarkable results and long-term stability. A 20-year-old girl presented with a convex profile due to severe mandibular retrognathia after a history of several TMJ surgeries for bilateral TMJ ankyloses. Mandibular distraction osteogenesis (MDO) was performed, and elastics were placed between the microimplants to control the direction of distraction. Subsequently, after retraction of the maxillary anterior teeth and distalisation of the whole mandibular dentition, the facial profile was markedly improved, and good interdigitation was obtained. The six-year follow-up retention and overall stability were satisfactory with good interdigitation and jaw function.

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