A Hybrid N-body--Coagulation Code for Planet Formation

We describe a hybrid algorithm to calculate the formation of planets from an initial ensemble of planetesimals. The algorithm uses a coagulation code to treat the growth of planetesimals into oligarchs and explicit N-body calculations to follow the evolution of oligarchs into planets. To validate the N-body portion of the algorithm, we use a battery of tests in planetary dynamics. Several complete calculations of terrestrial planet formation with the hybrid code yield good agreement with previously published calculations. These results demonstrate that the hybrid code provides an accurate treatment of the evolution of planetesimals into planets.Comment: Astronomical Journal, accepted; 33 pages + 11 figure

Synthetic long oligonucleotides to generate artificial templates for use as positive controls in molecular assays: drug resistance mutations in influenza virus as an example

<p>Abstract</p> <p>Background</p> <p>Positive controls are an integral component of any sensitive molecular diagnostic tool, but this can be affected, if several mutations are being screened in a scenario of a pandemic or newly emerging disease where it can be difficult to acquire all the necessary positive controls from the host. This work describes the development of a synthetic oligo-cassette for positive controls for accurate and highly sensitive diagnosis of several mutations relevant to influenza virus drug resistance.</p> <p>Results</p> <p>Using influenza antiviral drug resistance mutations as an example by employing the utility of synthetic paired long oligonucleotides containing complementary sequences at their 3' ends and utilizing the formation of oligonucleotide dimers and DNA polymerization, we generated ~170bp dsDNA containing several known specific neuraminidase inhibitor (NAI) resistance mutations. These templates were further cloned and successfully applied as positive controls in downstream assays.</p> <p>Conclusion</p> <p>This approach significantly improved the development of diagnosis of resistance mutations in terms of time, accuracy, efficiency and sensitivity, which are paramount to monitoring the emergence and spread of antiviral drug resistant influenza strains. Thus, this may have a significantly broader application in molecular diagnostics along with its application in rapid molecular testing of all relevant mutations in an event of pandemic.</p

New coil concept for endoluminal MR imaging: Initial results in staging of gastric carcinoma in correlation with Histopathology

Our aim was to conduct a prospective study to evaluate staging accuracy of a new coil concept for endoluminal magnetic resonance imaging (MRI) on ex vivo gastric carcinomas. Twenty-eight consecutive patients referred to surgery with a clinically proven primary gastric malignancy were included. Surgical specimens were examined with a foldable and self-expanding loop coil (8-cm diameter) at 1.5 Tesla immediately after total gastrectomy. T1- and T2-weighted and opposed-phase sequences (axial, frontal sections; 3- to 4-mm slice thickness) were acquired. Investigators blinded to any patient information analyzed signal intensity of normal gastric wall, gastric tumor, and lymph nodes. Findings were compared with histopathological staging. On surgical specimens, 2–5 gastric wall layers could be visualized. All gastric tumors (26 carcinomas, two lymphomas) were identified on endoluminal MR data (100%). Overall accuracy for T staging was 75% (18/24); sensitivity to detect serosal involvement was 80% and specificity 89%. N staging correlated in 58% (14/24) with histopathology (N+ versus N−). The endoluminal coil concept is feasible and applicable for an ex vivo setting. Endoluminal MR data provided sufficient detail for gastric wall layer differentiation, and therefore, identification of T stages in gastric carcinoma is possible. Further investigations in in vivo settings should explore the potential of our coil concept for endoluminal MR imaging

A New Hybrid N-Body-Coagulation Code for the Formation of Gas Giant Planets

We describe an updated version of our hybrid N-body-coagulation code for planet formation. In addition to the features of our 2006-2008 code, our treatment now includes algorithms for the 1D evolution of the viscous disk, the accretion of small particles in planetary atmospheres, gas accretion onto massive cores, and the response of N-bodies to the gravitational potential of the gaseous disk and the swarm of planetesimals. To validate the N-body portion of the algorithm, we use a battery of tests in planetary dynamics. As a first application of the complete code, we consider the evolution of Pluto-mass planetesimals in a swarm of 0.1-1 cm pebbles. In a typical evolution time of 1-3 Myr, our calculations transform 0.01-0.1 solar mass disks of gas and dust into planetary systems containing super-Earths, Saturns, and Jupiters. Low mass planets form more often than massive planets; disks with smaller alpha form more massive planets than disks with larger alpha. For Jupiter-mass planets, masses of solid cores are 10-100 Earth masses.Comment: revised version; 52 pages, 1 table, 19 figures; accepted in Ap

Ueber den Ausnahmefall einer doppelten Bahnbestimmung aus drei vollständigen geocentrischen Beobachtungen

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Auditory model-based selection of the most informative experimental conditions

Identifying the causes of a person's hearing impairment is a challenging task. Even though a broad range of measurement techniques exist, links between the results of one or several listening tests and possible pathologies need to be found. Drawing conclusions from measurement results that were influenced by pathologies in this highly non-linear auditory system remains very difficult. In addition, measurement time is restricted, especially in clinical settings. A central but difficult goal is to maximize the diagnostic information that is collectable within a certain time frame. Computer models simulating auditory processing and possible impairments could be employed to assist in such diagnostics. By using the model-based experiment-steering approach introduced in Hermann and Dietz (2021, Acta Acustica, 5:51, doi: 10.1051/aacus/2021043), the current study demonstrates its applicability using five young, normal-hearing subjects. In the model-based selection procedure, those stimuli providing the most information about the model parameters were identified in parallel to the measurement, and subsequently presented to the participant. The same binaural tone-in-noise detection task was conducted with two measurement procedures: A standard adaptive staircase procedure and the model-based selection procedure. For this proof of concept, an existing auditory processing model was adopted. Its four free parameters enabled the characterization of the subjects' 250 Hz channel. The model parameters best predicting the subject's sensitivity to a diotic and various dichotic conditions, were obtained using a maximum-likelihood approach. On average, the same accuracy of model parameter estimation was reached 2.5 times faster with the model-steered procedure compared to the standard adaptive procedure. Difficulties regarding the choice of a reliable model and issues to be considered when deciding on reasonable discretization steps of the model parameters are discussed. Although the physiological causes of an individual's results cannot be diagnosed with this procedure, a characterization in terms of functional parameters is possible