Stability of multiplanet systems in binaries

When exploring the stability of multiplanet systems in binaries, two parameters are normally exploited: the critical semimajor axis ac computed by Holman and Wiegert (1999) within which planets are stable against the binary perturbations, and the Hill stability limit Delta determining the minimum separation beyond which two planets will avoid mutual close encounters. Our aim is to test whether these two parameters can be safely applied in multiplanet systems in binaries or if their predictions fail for particular binary orbital configurations. We have used the frequency map analysis (FMA) to measure the diffusion of orbits in the phase space as an indicator of chaotic behaviour. First we revisited the reliability of the empirical formula computing ac in the case of single planets in binaries and we find that, in some cases, it underestimates by 10-20% the real outer limit of stability. For two planet systems, the value of Delta is close to that computed for planets around single stars, but the level of chaoticity close to it substantially increases for smaller semimajor axes and higher eccentricities of the binary orbit. In these configurations ac also begins to be unreliable and non linear secular resonances with the stellar companion lead to chaotic behaviour well within ac, even for single planet systems. For two planet systems, the superposition of mean motion resonances, either mutual or with the binary companion, and non linear secular resonances may lead to chaotic behaviour in all cases. We have developed a parametric semiempirical formula determining the minimum value of the binary semimajor axis, for a given eccentricity of the binary orbit, below which stable two planet systems cannot exist.Comment: Accepted on A&

Experimental evidence of guided resonances in photonic crystals with aperiodically-ordered supercells

We report on the first experimental evidence of guided resonances (GRs) in photonic crystal slabs based on aperiodically-ordered supercells. Using the Ammann-Beenker (quasiperiodic, 8-fold symmetric) tiling geometry, we present our study on the fabrication, experimental characterization, and full-wave numerical simulation of two representative structures (with different filling parameters) operating at near-infrared wavelengths (1300-1600 nm). Our results show a fairly good agreement between measurements and numerical predictions, and pave the way for the development of new strategies (based, e.g., on the lattice symmetry breaking) for GR engineering.Comment: 10 pages, 5 figures (minor revisions

The Actual Future is Open

Open futurism is the indeterministic position according to which the future is \u2018open\u2019, i.e., there is now no fact of the matter as to what future contingent events will actually obtain. Many open futurists hold a branching conception of time, in which a variety of possible futures exist. This paper introduces two challenges to branching-time open futurism, which are similar in spirit to a challenge posed by Fine to (standard) tense realism. The paper argues that, to address the new challenges, (branching-time) open futurists must (1) adopt an objective, non-perspectival notion of actuality and (2) subscribe to an A-theoretic, dynamic conception of reality. Moreover, given a natural understanding of \u201cactual future\u201d, (3) it is perfectly sensible for open futurists to hold that a unique, objectively actual future exists, contrary to a common assumption in the current debate. The paper also contends that recognising the existence of a unique actual future helps open futurists to avoid potential misconceptions

Obstructive sleep apnoea syndrome (OSAS): effects on the vestibular system

Aim of the present study was to evaluate the effects of obstructive sleep apnoea syndrome (OSAS) on the peripheral and central vestibular system, by means of a case series prospective study at the University referral centre of Otolaryngology Head and Neck Surgery; 45 consecutive patients suffering from OSAS were compared with a control group of 30 volunteer subjects selected from among the department employees. Severity of the disease was evaluated by means of cardio-respiratory function monitoring during sleep; the apnoea-hypopnoea index was calculated. Both groups underwent: 1) head and neck examination; 2) fibre-optic examination; 3) pure tone audiometry; 4) evaluation of eye movement disorders using oculomotility tests recorded with the help of video-nystagmography; 5) caloric vestibular responses recorded with video-nystagmography; 6) auditory brainstem response. Results, when evaluating our data, showed that the peripheral vestibular system may become asymmetric due to hypoxic damage while the central vestibular system corrects this disequilibrium

A numerical approach for the analysis of deformable journal bearings

This paper presents a numerical approach for the analysis of hydrodynamic radial journal bearings. The effect of shaft and housing elastic deformation on pressure distribution within oil film is investigated. An iterative algorithm that couples Reynolds equation with a plane finite elements structural model is solved. Temperature and pressure effects on viscosity are also included with the Vogel-Barus model. The deformed lubrication gap and the overall stress state were calculated. Numerical results are presented with reference to atypical journal bearing configuration at two different inlet oil temperatures. Obtained results show the great influence of elastic deformation of bearing components on oil pressure distribution, compared with results for ideally rigid components obtained by Raimondi and Boyd solution

Bipolar Quantum Molecular Resonance versus Blunt Dissection tonsillectomy

Bipolar Quantum Molecular Resonance versus Blunt Dissection tonsillectomy. Objectives: This study compared a quantum molecular resonance tonsillectomy (QMRT) to a standard blunt dissection tonsillectomy (BDT) for effectiveness and safety. Methodology: From January 2011 to September 2012, we recruited 80 children (ages 3 to 16 y) with paediatric obstructive sleep apnoea syndrome and/or recurrent tonsillitis. Patients were randomly assigned to receive QMRT (N = 40) or BDT (N = 40). The operating time and blood loss during surgery were evaluated. During the first postoperative week, the patients' parents completed a questionnaire to evaluate bleeding, ear and neck pain, nausea, vomiting, interrupted sleep, oral liquid intake or discomfort in fluid assumption, and analgesic consumption. Results: The average tonsillectomy duration was significantly shorter in the QMRT group (22.07 min \ub1 9.05) than in the BDT group (35.12 min \ub1 13.32; p < 0.000005). The average blood loss during tonsillectomy was significantly lower for the QMRT group (5.62 ml \ub1 7.44) than for the BDT group (43 ml \ub1 33.20; p < 000000001). However, the BDT group reported significantly lower pain scores than the QMRT group on days 2 (p < 0.05), 5 (p < 0.05), and 6 (p < 0.05); on other days, the groups were not significantly different. The BDT group reported two early and one late bleeding episodes; the QMRT group recorded only two late bleeding episodes. Conclusions: QMRT significantly reduced the operating time and intra-operative blood loss. No significant differences were found between the two techniques in postoperative pain or bleeding

Management of benign paroxysmal positional vertigo of lateral semicircular canal by Gufoni's manoeuvre

Benign paroxysmal positional vertigo (BPPV) of lateral semicircular canal (LSC) is one of the rarer forms of BPPV as compared to posterior semicircular canal BPPV. Various particle repositioning manoeuvres have been described in the literature as a mode of treating this condition Purpose: Evaluation and discussion of the procedure of the Gufoni\u2019s manoeuvre and its advantages in the treatment of BPPV of LSC Material and methods: Prospective study of 58 patients affected by LSC BPPV who where office-treated with Gufoni\u2019s manoeuvre Results: Seventy-nine percent of the patients so treated had complete resolution of symptons, and 6,9% did not show any improvement in their symptoms. The remaining 13,8% had a conversion into posterior semicircular canal BPPV during treatment and were successfully treated with Epley\u2019s or Semont\u2019s manoeuvre. Conclusions: Gufoni\u2019s manoeuvre is effective in treating patients suffering from BPPV of LSC; it is simple to perform; there are not many movements to execute, it needs low timeof positioning, and positions are comfortable to the patien

Uvulopalatopharyngoplasty with tonsillectomy in the treatment of severe OSAS

Objective: To establish the efficacy of uvulopalatopharyngoplasty with tonsillectomy for treating selected patients with severe obstructive sleep apnea syndrome Methodology: Retrospective study of patients who underwent clinical/instrumental evaluation and surgical treatment. Setting: University ENT division with a tertiary snoring referral center Participants: Twenty-two patients with normal body mass index affected by severe obstructive sleep apnea syndrome- Main outcome measures: Pre and post operative cardiopulmonary monitoring during sleep, daytime sleepiness evaluation, post treatment complication recording. Results: Complete response to therapy was obtained in 78% of patients. Four patients had relief of symptoms but retained apnea-hypopnea index scores greater than 5 Conclusions: Uvulopalatopharyngoplasty associated with tonsillectomy can be employed safely to treat patients with normal body mass index who suffer from severe obstructive sleep apne