Is the Rayleigh-Sommerfeld diffraction always an exact reference for high speed diffraction algorithms?

In several areas of optics and photonics like wave propagation, digital holography, holographic microscopy, diffraction imaging, biomedical imaging and diffractive optics, the behavior of the electromagnetic waves has to be calculated with the scalar theory of diffraction by computational methods. Many of these high speed diffraction algorithms based on a fast Fourier transformation are in principle approximations of the Rayleigh-Sommerfeld Diffraction (RSD) theory. However, to investigate their numerical accuracy, they should be compared with and verified by RSD. All numerical simulations are in principle based on a sampling of the analogue continuous field. In this article we demonstrate a novel validity condition for the well-sampling in RSD, which makes a systematic treatment of sampling in RSD possible. We show the fundamental restrictions due to this condition and the anomalies caused by its violation. We also demonstrate that the restrictions are completely removed by a sampling below the Abbe resolution limit. Furthermore, we present a very general unified approach for applying the RSD outside its validity domain by the combination of a forward and reverse calculation

On the Universality of Matrix Models for Random Surfaces

We present an alternative procedure to eliminate irregular contributions in the perturbation expansion of c=0-matrix models representing the sum over triangulations of random surfaces, thereby reproducing the results of Tutte [1] and Brezin et al. [2] for the planar model. The advantage of this method is that the universality of the critical exponents can be proven from general features of the model alone without explicit determination of the free energy and therefore allows for several straightforward generalizations including cases with non-vanishing central charge c< 1.Comment: 9 pages, 3 figure

The Complexity of Satisfiability for Sub-Boolean Fragments of ALC

The standard reasoning problem, concept satisfiability, in the basic description logic ALC is PSPACE-complete, and it is EXPTIME-complete in the presence of unrestricted axioms. Several fragments of ALC, notably logics in the FL, EL, and DL-Lite family, have an easier satisfiability problem; sometimes it is even tractable. All these fragments restrict the use of Boolean operators in one way or another. We look at systematic and more general restrictions of the Boolean operators and establish the complexity of the concept satisfiability problem in the presence of axioms. We separate tractable from intractable cases.Comment: 17 pages, accepted (in short version) to Description Logic Workshop 201

Nitrogen and phosphorus leakage in ecological recycling agriculture

In this report we quantify nitrogen and phosphorus leakage on three farms in the BERAS project. The study is based on direct measurements of nitrogen and phosphorus concentration in drainage water and water flow measurements

A Fourier-based Solving Approach for the Transport of Intensity Equation without Typical Restrictions

The Transport-of-Intensity equation (TIE) has been proven as a standard approach for phase retrieval. Some high efficiency solving methods for the TIE, extensively used in many works, are based on a Fourier-Transform (FT). However, to solve the TIE by these methods several assumptions have to be made. A common assumption is that there are no zero values for the intensity distribution allowed. The two most widespread Fourier-based approaches have further restrictions. One of these requires the uniformity of the intensity distribution and the other assumes the collinearity of the intensity and phase gradients. In this paper, we present an approach, which does not need any of these assumptions and consequently extends the application domain of the TIE

Coping with creeping catastrophes: national political systems and the challenge of slow-moving policy problems

No abstract available

Efficacy of a New Postpartum Transition Protocol for Avoiding Pregnancy

Introduction: The postpartum period is a challenging time for family planning, especially for women who breastfeed. Breastfeeding delays the return of menses (lactational amenorrhea), but ovulation often occurs before first menses. For this reason, a protocol was developed to assist women in identifying their return of fertility postpartum to avoid pregnancy. Methods: In this prospective, 12-month, longitudinal cohort study, 198 postpartum women aged 20 to 45 years (mean age, 30.2 years) were taught a protocol for avoiding pregnancy with either online or in-person instruction. A hand-held fertility monitor was used to identify the fertile period by testing for urinary changes in estrogen and luteinizing hormone, and the results were tracked on a web site. During lactational amenorrhea, urine testing was done in 20-day intervals. When menses returned, the monitor was reset at the onset of each new menstrual cycle. Participants were instructed to avoid intercourse during the identified fertile period. Kaplan-Meier survival analysis was used to calculate unintentional pregnancy rates through the first 12 months postpartum. Results: There were 8 unintended pregnancies per 100 women at 12 months postpartum. With correct use, there were 2 unintended pregnancies per 100 women at 12 months. Conclusion: The online postpartum protocol may effectively assist a select group of women in avoiding pregnancy during the transition to regular menstrual cycles

Effectiveness of an Online Natural Family Planning Program for Breastfeeding Women

Objective To analyze the effectiveness of an online, nurse-managed natural family planning (NFP) program among breastfeeding women and subgroups of these women. Design Longitudinal comparative cohort study. Setting A university-based online NFP education program and menstrual cycle charting system. Participants Women (N = 816) with a mean age of 30.3 years (standard deviation = 4.5) who registered to use the online NFP system and indicated they were breastfeeding. Methods Participants tracked their fertile times with an electronic hormone fertility monitor (EHFM), cervical mucus monitoring, or both. All unintended pregnancies were evaluated by professional nurses. Results The correct use pregnancy rates were 3 per 100 users over 12 cycles of use, and typical rates were 14 per 100 at 12 cycles of use. At 12 cycles of use, total pregnancy rates were 16 per 100 for electronic hormone fertility monitor users (n = 380), 81 per 100 among mucus-only users (n = 45), and 14 per 100 for electronic hormone fertility monitor plus mucus users (n = 391). Conclusion Use of a nurse-managed online NFP program for women can be effective to help women avoid pregnancy while breastfeeding, especially with correct and consistent use

Sparsity Invariant CNNs

In this paper, we consider convolutional neural networks operating on sparse inputs with an application to depth upsampling from sparse laser scan data. First, we show that traditional convolutional networks perform poorly when applied to sparse data even when the location of missing data is provided to the network. To overcome this problem, we propose a simple yet effective sparse convolution layer which explicitly considers the location of missing data during the convolution operation. We demonstrate the benefits of the proposed network architecture in synthetic and real experiments with respect to various baseline approaches. Compared to dense baselines, the proposed sparse convolution network generalizes well to novel datasets and is invariant to the level of sparsity in the data. For our evaluation, we derive a novel dataset from the KITTI benchmark, comprising 93k depth annotated RGB images. Our dataset allows for training and evaluating depth upsampling and depth prediction techniques in challenging real-world settings and will be made available upon publication