Planet transit and stellar granulation detection with interferometry

Aims. We used realistic three-dimensional (3D) radiative hydrodynamical (RHD) simulations from the Stagger-grid and synthetic images computed with the radiative transfer code Optim3D to provide interferometric observables to extract the signature of stellar granulation and transiting planets. Methods. We computed intensity maps from RHD simulations for twelve interferometric instruments covering wavelengths ranging from optical to infrared. The stellar surface asymmetries in the brightness distribution mostly affect closure phases. We compared the closure phases of the system star with a transiting planet and the star alone and considered the impact of magnetic spots constructing a hypothetical starspots image. Results. All the simulations show departure from the axisymmetric case at all wavelengths. We presented two possible targets (Beta Com and Procyon) and found that departures up to 16 deg can be detected on the 3rd lobe and higher. In particular, MIRC is the most appropriate instrument because it combines good UV coverage and long baselines. Moreover, we explored the impact of convection on interferometric planet signature for three prototypes of planets. It is possible to disentangle the signature of the planet at particular wavelengths (either in the infrared or in the optical) by comparing the closure phases of the star at difference phases of the planetary transit. Conclusions. The detection and characterisation of planets must be based on a comprehensive knowledge of the host star; this includes the detailed study of the stellar surface convection with interferometric techniques. In this context, RHD simulations are crucial to reach this aim. We emphasize that interferometric observations should be pushed at high spatial frequencies by accumulating observations on closure phases at short and long baselines.Comment: accepted in Astronomy and Astrophysics, 13 pages. Some figures have reduced resolution to decrease the size of the output file. Please contact [email protected] to have the high resolution version of the pape

A numerical study of infinitely renormalizable area-preserving maps

It has been shown in (Gaidashev et al, 2010) and (Gaidashev et al, 2011) that infinitely renormalizable area-preserving maps admit invariant Cantor sets with a maximal Lyapunov exponent equal to zero. Furthermore, the dynamics on these Cantor sets for any two infinitely renormalizable maps is conjugated by a transformation that extends to a differentiable function whose derivative is Holder continuous of exponent alpha>0. In this paper we investigate numerically the specific value of alpha. We also present numerical evidence that the normalized derivative cocycle with the base dynamics in the Cantor set is ergodic. Finally, we compute renormalization eigenvalues to a high accuracy to support a conjecture that the renormalization spectrum is real

Мессояха – газогидратная залежь, роль и значение

Описаны геология и технологии эксплуатации Мессояхского газогидратного месторождения. Опыт его разработки показывает: газогидратные залежи (ГГЗ) следует активно вводить в разработку; каждая ГГЗ требует “персональной” технологии разработки; необходимо глубоко, на молекулярном уровне изучать свойства гидратонасыщенных пород и флюида, который в них содержится; необходимы принципиально новые технологии разработки ГГЗ и транспорта гидратного газа.Охарактеризовано геологічну будову й технологію розробки Мессояхського газогідратного родовища. Досвід його розробки засвідчив: газогідратні поклади (ГГП) слід активно вводити у розробку; кожна ГГП вимагає індивідуальних технологій розробки; необхідно глибоко, на молекулярному рівні вивчати властивості гідратонасичених порід та флюїда, що в них міститься; потрібно створювати принципово нові технології розробки ГГП та транспорту гідратного газу.Geology and technology of Messoyakhska field developing are discribed. Experience clearly shows: development of gas hydrate fields should be actively promoted; each gas hydrates field requires a specific development technology; it is necessary to research at the molecular level the properties of hydrate saturated rocks and is required; develop a fundamentally new technologies of hydrated gas production is vital

До 85-річчя Ісаака Бенціоновича Клеймана

У 2006 р. виповнилося 85 років одному з найшановніших археологів Одеси, відомому досліднику стародавньої Тіри Ісааку Бенціоновичу Клейману

Dynamics of the Universal Area-Preserving Map Associated with Period Doubling: Hyperbolic Sets

It is known that the famous Feigenbaum-Coullet-Tresser period doubling universality has a counterpart for area-preserving maps of {\fR}^2. A renormalization approach has been used in \cite{EKW1} and \cite{EKW2} in a computer-assisted proof of existence of a "universal" area-preserving map $F_*$ -- a map with orbits of all binary periods 2^k, k \in \fN. In this paper, we consider maps in some neighbourhood of $F_*$ and study their dynamics. We first demonstrate that the map $F_*$ admits a "bi-infinite heteroclinic tangle": a sequence of periodic points $\{z_k\}$, k \in \fZ, |z_k| \converge{{k \to \infty}} 0, \quad |z_k| \converge{{k \to -\infty}} \infty, whose stable and unstable manifolds intersect transversally; and, for any N \in \fN, a compact invariant set on which $F_*$ is homeomorphic to a topological Markov chain on the space of all two-sided sequences composed of $N$ symbols. A corollary of these results is the existence of {\it unbounded} and {\it oscillating} orbits. We also show that the third iterate for all maps close to $F_*$ admits a horseshoe. We use distortion tools to provide rigorous bounds on the Hausdorff dimension of the associated locally maximal invariant hyperbolic set: $$ 0.7673 \ge {\rm dim}_H(\cC_F) \ge \varepsilon \approx 0.00044 e^{-1797}.$

Open versus laparoscopically-assisted oesophagectomy for cancer: a multicentre randomised controlled phase III trial - the MIRO trial

<p>Abstract</p> <p>Background</p> <p>Open transthoracic oesophagectomy is the standard treatment for infracarinal resectable oesophageal carcinomas, although it is associated with high mortality and morbidity rates of 2 to 10% and 30 to 50%, respectively, for both the abdominal and thoracic approaches. The worldwide popularity of laparoscopic techniques is based on promising results, including lower postoperative morbidity rates, which are related to the reduced postoperative trauma. We hypothesise that the laparoscopic abdominal approach (laparoscopic gastric mobilisation) in oesophageal cancer surgery will decrease the major postoperative complication rate due to the reduced surgical trauma.</p> <p>Methods/Design</p> <p>The MIRO trial is an open, controlled, prospective, randomised multicentre phase III trial. Patients in study arm A will receive laparoscopic-assisted oesophagectomy, i.e., a transthoracic oesophagectomy with two-field lymphadenectomy and laparoscopic gastric mobilisation. Patients in study arm B will receive the same procedure, but with the conventional open abdominal approach. The primary objective of the study is to evaluate the major postoperative 30-day morbidity. Secondary objectives are to assess the overall 30-day morbidity, 30-day mortality, 30-day pulmonary morbidity, disease-free survival, overall survival as well as quality of life and to perform medico-economic analysis. A total of 200 patients will be enrolled, and two safety analyses will be performed using 25 and 50 patients included in arm A.</p> <p>Discussion</p> <p>Postoperative morbidity remains high after oesophageal cancer surgery, especially due to major pulmonary complications, which are responsible for 50% of the postoperative deaths. This study represents the first randomised controlled phase III trial to evaluate the benefits of the minimally invasive approach with respect to the postoperative course and oncological outcomes in oesophageal cancer surgery.</p> <p>Trial Registration</p> <p><a href="http://www.clinicaltrials.gov/ct2/show/NCT00937456">NCT00937456</a> (ClinicalTrials.gov)</p

Absence of VHL gene alteration and high VEGF expression are associated with tumour aggressiveness and poor survival of renal-cell carcinoma

International audienceBACKGROUND: The von Hippel-Lindau gene (VHL) alteration, a common event in sporadic clear-cell renal-cell carcinoma (CCRCC), leads to highly vascularised tumours. Vascular endothelial growth factor (VEGF) is the major factor involved in angiogenesis, but the prognostic significance of both VHL inactivation and VEGF expression remain controversial. The aims of this study were to analyse the relationship between VHL genetic and epigenetic alterations, VHL expression and VEGF tumour or plasma expression, and to analyse their respective prognostic value in patients with CCRCC. METHODS: A total of 102 patients with CCRCC were prospectively analysed. Alterations in VHL were determined by sequencing, Multiplex Ligation-dependent Probe Amplification (MLPA) and methylation-specific MLPA. Expression of pVHL and VEGF was determined by immunohistochemistry. Plasma VEGF was measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: VHL mutation, deletion and promoter methylation were identified in 70, 76 and 14 cases, respectively. Overall, at least one VHL-gene alteration occurred in 91 cases (89.2%). Both VEGF tumour and plasma expression appeared to be decreased in case of VHL alteration. Median progression-free survival and CCRCC-specific survival were significantly reduced in patients with wild-type VHL or altered VHL and high VEGF expression, which, therefore, represent two markers of tumour aggressiveness in CCRCC. CONCLUSION: Stratifying CCRCCs according to VHL and VEGF status may help tailor therapeutic strategy

The influence of early aging on eye movements during motor simulation

Movement based interventions such as imagery and action observation are used increasingly to support physical rehabilitation of adults during early aging. The efficacy of these more covert approaches is based on an intuitively appealing assumption that movement execution, imagery and observation share neural substrate; alteration of one influences directly the function of the other two. Using eye movement metrics this paper reports findings that question the congruency of the three conditions. The data reveal that simulating movement through imagery and action observation may offer older adults movement practice conditions that are not constrained by the age-related decline observed in physical conditions. In addition, the findings provide support for action observation as a more effective technique for movement reproduction in comparison to imagery. This concern for imagery was also seen in the less congruent temporal relationship in movement time between imagery and movement execution suggesting imagery inaccuracy in early aging