Weighted ICP Algorithm for Alignment of Stars from Scanned Astronomical Photographic Plates

ACM Computing Classification System (1998): I.2.8, I.2.10, I.5.1, J.2.Given the coarse celestial coordinates of the centre of a plate scan and the field of view, we are looking for a mapping between the stars extracted from the image and the stars from a catalogue, where the stars from both sources are represented by their stellar magnitudes and coordinates, relatively to the image centre. In a previous work we demonstrated the application of Iterative Closest Point (ICP) algorithm for the alignment problem where stars were represented only by their geometrical coordinates. ICP leads to translation and rotation of the initial points - a correction required for one set of stars to fit over the other. This paper extends the previous work by demonstrating significant improvement of ICP by using the stellar magnitudes as point weights. The improvement consists of great decrease of the iteration count until convergence, which helps in the case of highly “misaligned” initial states. The essential aspects of the ICP method like noise tolerance of false or missing stars are still in charge.This work is partially supported by the following projects: (1) Creative Development Support of Doctoral Students, Post-Doctoral and Young Researches in the Field of Computer Science, BG 051-PO-001-3.3.04/13, European Social Fund 2007–2013, Operational programme “Human resources development”, and (2) Astroinformatics, grant DO-02-275/2008 of the National Science Fund of the Bulgarian Ministry of Education, Youth and Science

Laparoscopic nephropexy: Treatment outcome and quality of life

INTRODUCTION: Surgical treatment of nephroptosis is rarely performed nowаdays and is done only in symptomatic patients. Here we present the results of our laparoscopic nephropexy in patients with symp­tomatic nephroptosis.MATERIALS AND METHODS: For a period from March 2014 to March 2015, a total of 8 women at an av­erage age of 54 years were operated on in our clinic . Four of the patients were with nephroptosis of the left kidney, three of the right one and one had bilateral nephroptosis. Most of the patients complained of pain and discomfort in active movement, only one individual had complaints consisting of intermittent macro­scopic hematuria. One patient had been operated on in the past by a classic open method of the same kidney. Preoperatively, for all patients, intravenous urography in supine and standing position was performed. All patients were operated on trans-peritoneally through 3 ports: 1x10 mm and 2x5 mm. The kidney was com­pletely mobilized and kidney fat was dissected. The upper and middle pole of the kidney were fixed to mus­culus psoas major, using a single non-absorbable suture and intracorporeal technique for tying.RESULT: All operations were performed with minimal blood loss, an average operating time of 45 minutes and a hospital stay of 4 days. No conversion was required in any of the cases. Postoperatively, patients were tracked and monitored by ultrasound examination. At 3 months we did IVP, which showed the correct loca­tion of the kidney. All patients remained asymptomatic for an average of 11 months after surgery.CONCLUSION: Laparoscopic transperitoneal nephropexy is a safe and effective procedure and a promising method for correction of symptomatic nephroptosis

Laparoscopic radical cystectomy - initial experience

Introduction: Radical cystectomy with extended pelvic lymph node dissection is the standard treatment for muscle-invasive bladder cancer. The aim of this study is to report our initial experience of our series of 22 patients who underwent laparoscopic radical cystectomy with different urinary diversion.Materials and Methods: Between March 2015 and March 2016, 22 patients underwentlaparoscopic radical cystectomy with different types of extracorporeal urinary diversion. Patients were aged 54 to 85 (average age 66.3) with different clinical stages of the disease.Transperitoneal laparoscopic radical cystectomy with five ports in all cases was performed with bilateral extended pelvic lymph node dissection.Results: In 5 cases we performed radical cystectomy with subsequent ureterocutaneostomy, in 7 cases we performed ileal conduit according to the method of Bricker, and in 10 cases we formed orthotopic bladder from ileal loop by the method of Hautmann. All operations were performed with an average blood loss of 270 ml, with an average operating time of 5 hours, and an average hospital stay of 7 days. No conversion was required in any case. The patients were observed postoperatively. Early complications (within 30 days) occurred in 2 patients, and late complications occurred in 3 patients.Conclusion: Laparoscopic radical cystectomy is possible, although technically difficult, with significant reduction in patient morbidity. With more experience and an improvement of the surgical technique, laparoscopic radical cystectomy with different types of derivation becomes an alternative surgical method for treating patients with localised muscle invasive bladder carcinoma

Numerical study of anharmonic vibrational decay in amorphous and paracrystalline silicon

The anharmonic decay rates of atomic vibrations in amorphous silicon (a-Si) and paracrystalline silicon (p-Si), containing small crystalline grains embedded in a disordered matrix, are calculated using realistic structural models. The models are 1000-atom four-coordinated networks relaxed to a local minimum of the Stillinger-Weber interatomic potential. The vibrational decay rates are calculated numerically by perturbation theory, taking into account cubic anharmonicity as the perturbation. The vibrational lifetimes for a-Si are found to be on picosecond time scales, in agreement with the previous perturbative and classical molecular dynamics calculations on a 216-atom model. The calculated decay rates for p-Si are similar to those of a-Si. No modes in p-Si reside entirely on the crystalline cluster, decoupled from the amorphous matrix. The localized modes with the largest (up to 59%) weight on the cluster decay primarily to two diffusons. The numerical results are discussed in relation to a recent suggestion by van der Voort et al. [Phys. Rev. B {\bf 62}, 8072 (2000)] that long vibrational relaxation inferred experimentally may be due to possible crystalline nanostructures in some types of a-Si.Comment: 9 two-column pages, 13 figure

Bridging the gap between omics and earth system science to better understand how environmental change impacts marine microbes

The advent of genomic-, transcriptomic- and proteomic-based approaches has revolutionized our ability to describe marine microbial communities, including biogeography, metabolic potential and diversity, mechanisms of adaptation, and phylogeny and evolutionary history. New interdisciplinary approaches are needed to move from this descriptive level to improved quantitative, process-level understanding of the roles of marine microbes in biogeochemical cycles and of the impact of environmental change on the marine microbial ecosystem. Linking studies at levels from the genome to the organism, to ecological strategies and organism and ecosystem response, requires new modelling approaches. Key to this will be a fundamental shift in modelling scale that represents micro-organisms from the level of their macromolecular components. This will enable contact with omics data sets and allow acclimation and adaptive response at the phenotype level (i.e. traits) to be simulated as a combination of fitness maximization and evolutionary constraints. This way forward will build on ecological approaches that identify key organism traits and systems biology approaches that integrate traditional physiological measurements with new insights from omics. It will rely on developing an improved understanding of ecophysiology to understand quantitatively environmental controls on microbial growth strategies. It will also incorporate results from experimental evolution studies in the representation of adaptation. The resulting ecosystem-level models can then evaluate our level of understanding of controls on ecosystem structure and function, highlight major gaps in understanding and help prioritize areas for future research programs. Ultimately, this grand synthesis should improve predictive capability of the ecosystem response to multiple environmental drivers

Probing competitive interactions in quaternary formulations

Hypothesis The interaction of amphiphilic block copolymers of the poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) (PEO–PPO–PEO) group with small molecule surfactants may be “tuned” by the presence of selected alcohols, with strong interactions leading to substantial changes in (mixed) micelle morphology, whilst weaker interactions lead to coexisting micelle types. Experiments The nature and the strength of the interactions between Pluronic P123 (EO20PO70EO20) and small molecule surfactants (anionic sodium dodecylsulfate, SDS, C12SO4Na), (cationic dodecyltrimethylammonium bromide, C12TAB) and (non-ionic polyoxyethylene(23)lauryl ether, Brij 35, C12EO23OH) is expected to depend on the partitioning of the short, medium and long chain alcohols (ethanol, hexanol and decanol respectively) and was probed using tensiometry, pulsed-gradient spin-echo nuclear magnetic resonance (PGSE-NMR) and small-angle neutron scattering (SANS). Findings The SANS data for aqueous P123 solutions with added alcohols were well described by a charged spherical core/shell model for the micelle morphology. The addition of the surfactants led to significantly smaller, oblate elliptical mixed micelles in the absence of alcohols. Addition of ethanol to these systems led to a decrease in the micelle size, whereas larger micelles were observed upon addition of the longer chain alcohols. NMR studies provided complementary estimates of the micelle composition, and the partitioning of the various components into the micelle

Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO