1,363 research outputs found
MetaBETA: Model and Implementation
Object-oriented programming languages are excellent for expressing abstractions in many application domains. The object-oriented programming methodology allows real-world concepts to modelled in an easy and direct fashion and it supports refinement of concepts. However, many object-oriented languages and their implementations fall short in two areas: dynamic extensibility and reflection.Dynamic extensibility is the ability to incorporate new classes into an application at runtime. Reflection makes it possible for a language to extend its own domain, e.g., to build type-orthogonal functionality. MetaBETA is an extension of the BETA language that supports dynamic extensibility and reflection. MetaBETA has a metalevel interface that provides access to the state of a running application and to the default implementation of language primities.This report presents the model behind MetaBETA. In particular, we discuss the execution model of a MetaBETA program and how type- orthogonal abstractions can be built. This includes precentation of dynamic slots, a mechanism that makes is possible ectend objects at runtime. The other main area covered in this report is the implementation of MetaBETA. The central component of the architecture is a runtime system, which is viewed as a virtual machine whose baselevel interface implements the functionality needed by the programming language
Operation of a Microfabricated Planar Ion-Trap for Studies of a Yb-Rb Hybrid Quantum System
In order to study interactions of atomic ions with ultracold neutral atoms,
it is important to have sub-m control over positioning ion crystals.
Serving for this purpose, we introduce a microfabricated planar ion trap
featuring 21 DC electrodes. The ion trap is controlled by a home-made FPGA
voltage source providing independently variable voltages to each of the DC
electrodes. To assure stable positioning of ion crystals with respect to
trapped neutral atoms, we integrate into the overall design a compact mirror
magneto optical chip trap (mMOT) for cooling and confining neutral Rb
atoms. The trapped atoms will be transferred into an also integrated chipbased
Ioffe-Pritchard trap potential formed by a Z-shaped wire and an external bias
magnetic field.We introduce the hybrid atom-ion chip, the microfabricated
planar ion trap and use trapped ion crystals to determine ion lifetimes, trap
frequencies, positioning ions and the accuracy of the compensation of
micromotion.Comment: 10 pages, 13 figure
FPGA based Speech Separation using IPD Features
The problem of speaker separation is an established field in science and goes back to the cocktail party problem defined in 1953. For decades, methods have been improved and developed, but the computational complexity is rarely considered just as the possibility to use hardware acceleration mechanisms. For this reason, this paper addresses the research question: how speaker separation can be realized on embedded systems by exploiting parallelization and intelligent hardware/software partitioning. For this purpose, a concept is described which uses an FPGA for parallelization to separate a speech signal from an intended direction providing a constant throughput rate. The implementation results show the independence of FPGA resources except BRAM size, proving the scalability of the concept, just as the real-time capabilities
PREOVULATORY CHANGES AND OVULATION IN CATTLE UNDERGOING SPONTANEOUS OR CLOPROSTENOL-INDUCED LUTEOLYSIS
The follicular population, diameter of the ovulatory and subordinate follicles, corpus luteum (CL) size, concentration of progesterone and estradiol-17p were studied following spontaneous or cloprostenol-induced luteolysis. A total of 14 heifers received cloprostenol treatment on Day 9-11 of the cycle to synchronize their estrus. Subsequently, they were divided into two groups, one group which was allowed to undergo spontaneous luteolysis and the other group in which estrus was induced from days 9 to 12. In the induced-group, transrectal ultrasonography were performed daily started two days prior to injection until the onset of estrus. In the spontaneous-group, ultrasonography was done daily from day 15 until the onset of estrus. In both groups scanning were performed every 4 h from the onset of estrus until ovulation was ascertained. Small (SF, 2-4 mm), medium (MF.5-9 mm ) and large (LF,>9mm) size follicles were recorded. The diameter of largest and subordinate follicles were measured and blood were drawn from jugular vein at approximately around scanning and the plasma were used for measurement of progesterone (P4) and estradiol-17p (E2) concentration. There was no different in term of number of SF, MF and LF (P>0.05) between the two groups. Similarly, no effect of side (left vs. right ovary) and CL position (ipsi- vs contralateral to the ovary) was found (P>0.05). However, it was demonstrated that mean number of ovulatory follicles was higher (PO.01) in the spontaneously ovulating group while the regressing-CL size was larger in the cloprostenol induced animals (
Effect of montelukast on platelet activating factor- and tachykinin induced mucus secretion in the rat
Background: Platelet activating factor and tachykinins (substance P, neurokinin A, neurokinin B) are important mediators contributing to increased airway secretion in the context of different types of respiratory diseases including acute and chronic asthma. Leukotriene receptor antagonists are recommended as add-on therapy for this disease. The cys-leukotriene-1 receptor antagonist montelukast has been used in clinical asthma therapy during the last years. Besides its inhibitory action on bronchoconstriction, only little is known about its effects on airway secretions. Therefore, the aim of this study was to evaluate the effects of montelukast on platelet activating factor- and tachykinin induced tracheal secretory activity.
Methods: The effects of montelukast on platelet activating factor- and tachykinin induced tracheal secretory activity in the rat were assessed by quantification of secreted 35SO4 labelled mucus macromolecules using the modified Ussing chamber technique.
Results: Platelet activating factor potently stimulated airway secretion, which was completely inhibited by the platelet activating factor receptor antagonist WEB 2086 and montelukast. In contrast, montelukast had no effect on tachykinin induced tracheal secretory activity.
Conclusion: Cys-leukotriene-1 receptor antagonism by montelukast reverses the secretagogue properties of platelet activating factor to the same degree as the specific platelet activating factor antagonist WEB 2086 but has no influence on treacheal secretion elicited by tachykinins. These results suggest a role of montelukast in the signal transduction pathway of platelet activating factor induced secretory activity of the airways and may further explain the beneficial properties of cys-leukotriene-1 receptor antagonists
One-sample log-rank tests with consideration of reference curve sampling variability
The one-sample log-rank test is the method of choice for single-arm Phase II
trials with time-to-event endpoint. It allows to compare the survival of the
patients to a reference survival curve that typically represents the expected
survival under standard of care. The classical one-sample log-rank test,
however, assumes that the reference survival curve is deterministic. This
ignores that the reference curve is commonly estimated from historic data and
thus prone to statistical error. Ignoring sampling variability of the reference
curve results in type I error rate inflation. For that reason, a new one-sample
log-rank test is proposed that explicitly accounts for the statistical error
made in the process of estimating the reference survival curve. The test
statistic and its distributional properties are derived using martingale
techniques in the large sample limit. In particular, a sample size formula is
provided. Small sample properties regarding type I and type II error rate
control are studied by simulation. A case study is conducted to study the
influence of several design parameters of a single-armed trial on the inflation
of the type I error rate when reference curve sampling variability is ignored.Comment: 24 pages, 2 pictures, 1 supplementary fil
Aerosol optical depth retrieval from the EarthCARE Multi-Spectral Imager: the M-AOT product
The Earth Explorer mission Earth Clouds, Aerosols and Radiation Explorer (EarthCARE) will not only provide profile information on aerosols but also deliver a horizontal context to it through measurements by its Multi-Spectral Imager (MSI). The columnar aerosol product relying on these passive signals is called M-AOT (MSI-Aerosol Optical Thickness). Its main parameters are aerosol optical thickness (AOT) at 670 nm over ocean and valid land pixels and at 865 nm over ocean. Here, the algorithm and assumptions behind it are presented. Further, first examples of product parameters are given based on applying the algorithm to simulated EarthCARE test data and Moderate Resolution Imaging Spectroradiometer (MODIS) Level-1 data. Comparisons to input fields used for simulations, to the official MODIS aerosol product, to AErosol RObotic NETwork (AERONET) and to Maritime Aerosol Network (MAN) show an overall reasonable agreement. Over ocean, correlations are 0.98 (simulated scenes), 0.96 (compared to MYD04) and 0.9 (compared to MAN). Over land, correlations are 0.62 (simulated scenes), 0.87 (compared to MYD04) and 0.77 (compared to AERONET). A concluding discussion will focus on future improvements that are necessary and envisioned to enhance the product
Natural History of Pediatric Low-Grade Glioma Disease – First Multi-State Model Analysis
Background: Pediatric low-grade glioma [PLGG] is often a chronic progressive disease requiring multiple treatments, i.e. surgery, chemotherapy and irradiation. The multi-state model [MSM] allows an extended analysis of disease-states, that patients may undergo, incorporating competing risks over the course of time. Purpose: We studied disease-state-probabilities of the German SIOP-LGG 2004 cohort from the initial state "diagnosis" to the final state "death". Transient "disease-states" incorporated successive surgical and non-surgical treatments. We evaluated clinical risk factors for highly progressive disease requiring multiple interventions and death. Results: We identified 22 states within 1587 patients (median follow-up 6.3 years). For robust statistical calculation, we reduced the model to 7 states and eventually to three levels of disease-progressiveness: non, low and highly progressive. Five years after diagnosis state-probabilities were: 0.11 no therapy, 0.49 one and 0.11 two or more surgeries only, 0.19 one and 0.06 two or more non-surgical interventions with or without prior surgery. At this time point higher probability for highly progressive disease was found in infants (0.30), supratentorial-midline location (0.17) and diffuse astrocytoma WHO-grade II (0.12). Neurofibromatosis type-1 patients were most likely not to be treated (0.36) or to have received only non-surgical therapy (0.45). Two years after diagnosis 3-year predictions for highly progressive disease and death increased with the number of interventions patients underwent in the first 2 years after diagnosis. Conclusion: In this first MSM analysis we delineated a refined description of PLGG disease course over time, identifying three levels of progressiveness. Growth behavior in the first two years predicted future progressiveness and death
Acquisition Concept for Inter-Satellite Communication Terminals on CubeSats
Free Space Optical (FSO) communication is gaining ground in satellite industry and an ideal
supplement to classical radio data transmission. It offers solutions for global, high-rate and secure
communication channels with compact designs and high cost- and performance-efficiency. Thus,
German Aerospace Center (DLR) develops laser communication terminals for CubeSats and small
satellites.
DLR has a long heritage in developing FSO terminals for Low Earth Orbit (LEO) satellites in the
Direct To Earth (DTE) scenario. The next step is to transfer this technology to Inter-Satellite Links
(ISL). This paper presents DLR’s current development of an ISL laser communication terminal for
CubeSats “CubeISL”. The optical terminal of CubeISL relies on the basic development of the
“OSIRIS4CubeSat” (O4C) payload. To establish a link between the corresponding CubeISLterminals, DLR developed a search algorithm to acquire the laser of the partner terminal on the other
satellite. The paper discusses the possibilities of different concepts based on the current design.
CubeISL will be demonstrated in a mission with two 6U CubeSats. Beside the technical description
of the payload design and the search and acquisition algorithm, the paper will also give an overview
and an outlook to this demonstrator missio
- …