Sensitivity of ENSO characteristics to a new interactive flux correction scheme in a coupled GCM

A fast coupled global climate model (CGCM) is used to study the sensitivity of El Niño Southern Oscillation (ENSO) characteristics to a new interactive flux correction scheme. With no flux correction applied our CGCM reveals typical bias in the background state: for instance, the cold tongue in the tropical east Pacific becomes too cold, thus degrading atmospheric sensitivity to variations of sea surface temperature (SST). Sufficient atmospheric sensitivity is essential to ENSO. Our adjustment scheme aims to sustain atmospheric sensitivity by counteracting the SST drift in the model. With reduced bias in the forcing of the atmosphere, the CGCM displays ENSO-type variability that otherwise is absent. The adjustment approach employs a one-way anomaly coupling from the ocean to the atmosphere: heat fluxes seen by the ocean are based on full SST, while heat fluxes seen by the atmosphere are based on anomalies of SST. The latter requires knowledge of the model's climatological SST field, which is accumulated interactively in the spin-up phase ("training"). Applying the flux correction already during the training period (by utilizing the evolving SST climatology) is necessary for efficiently reducing the bias. The combination of corrected fluxes seen by the atmosphere and uncorrected fluxes seen by the ocean implies a restoring mechanism that counteracts the bias and allows for long stable integrations in our CGCM. A suite of sensitivity runs with varying training periods is utilized to study the effect of different levels of bias in the background state on important ENSO properties. Increased duration of training amplifies the coupled sensitivity in our model and leads to stronger amplitudes and longer periods of the Nino3. 4 index, increased emphasis of warm events that is reflected in enhanced skewness, and more pronounced teleconnections in the Pacific. Furthermore, with longer training durations we observe a mode switch of ENSO in our model that closely resembles the observed mode switch related to the mid-1970s "climate shift". © 2010 The Author(s)

Characterizing the transmission potential of zoonotic infections from minor outbreaks.

The transmission potential of a novel infection depends on both the inherent transmissibility of a pathogen, and the level of susceptibility in the host population. However, distinguishing between these pathogen- and population-specific properties typically requires detailed serological studies, which are rarely available in the early stages of an outbreak. Using a simple transmission model that incorporates age-stratified social mixing patterns, we present a novel method for characterizing the transmission potential of subcritical infections, which have effective reproduction number R<1, from readily available data on the size of outbreaks. We show that the model can identify the extent to which outbreaks are driven by inherent pathogen transmissibility and pre-existing population immunity, and can generate unbiased estimates of the effective reproduction number. Applying the method to real-life infections, we obtained accurate estimates for the degree of age-specific immunity against monkeypox, influenza A(H5N1) and A(H7N9), and refined existing estimates of the reproduction number. Our results also suggest minimal pre-existing immunity to MERS-CoV in humans. The approach we describe can therefore provide crucial information about novel infections before serological surveys and other detailed analyses are available. The methods would also be applicable to data stratified by factors such as profession or location, which would make it possible to measure the transmission potential of emerging infections in a wide range of settings

Skeletally Dugundji spaces

We introduce and investigate the class of skeletally Dugundji spaces as a skeletal analogue of Dugundji space. The main result states that the following conditions are equivalent for a given space $X$: (i) $X$ is skeletally Dugundji; (ii) Every compactification of $X$ is co-absolute to a Dugundji space; (iii) Every $C^*$-embedding of the absolute $p(X)$ in another space is strongly $\pi$-regular; (iv) $X$ has a multiplicative lattice in the sense of Shchepin \cite{s76} consisting of skeletal maps

Expected Duration of Adverse Pregnancy Outcomes after Zika Epidemic.

Evidence is increasing that Zika virus-related adverse outcomes can occur throughout pregnancy. Mathematical modeling analysis using reported outcome data suggests that surveillance for these outcomes should begin as soon as an outbreak is detected and should continue for 40 weeks after the outbreak ends

Nonlocal communication with photoinduced structures at the surface of a polymer film

Nonlocal communication between two laser light beams is experimented in a photochromic polymer thin films. Information exchange between the beams is mediated by the self-induction of a surface relief pattern. The exchanged information is related to the pitch and orientation of the grating. Both are determined by the incident beam. The process can be applied to experiment on a new kind of logic gates.Comment: 7 pages, 4 figures, 2 table

Multistate polarization addressing using one single beam in an azo polymer film

Peculiar light-matter interactions can break the rule that a single beam polarization can address only two states in an optical memory device. Multistate storage of a single beam polarization is achieved using self-induced surface diffraction gratings in a photo-active polymer material. The grating orientation follows the incident light beam polarization direction. The permanent self-induced surface relief grating can be readout in real time using the same laser beam.Comment: 11 pages,3 figure

The representativity index of a simple monitoring network with regular theoretical shapes and its practical application for the existing groundwater monitoring network of the Tychy-Urbanowice landfills, Poland

The representativity index Ru is a measure used in assessing the chemical status of groundwater based on monitoring studies. This index is designed to describe the spatial homogeneity of the monitoring network. The general formula for calculating the index Ru includes the following parameters: average distance to the nearest monitoring point, number of monitoring points, and size of the test area. Calculations to determine the representativity index for four different shapes of the theoretical test study with the same area and the same number of monitoring points have been done. These calculations suggest that the index value depends on the shape and the position of these points, and it is less dependent on the size of the surface. An assessment of the representativeness of the monitoring network for the different numbers and configurations of the piezometers around the Tychy-Urbanowice landfills based on the mentioned index has been done as well. The best and the worst configurations of the monitoring network for these landfill sites in mathematical terms have been presented in this paper. The results are surprising: the highest index value is obtained with a single measurement point. The calculations were performed with the area of landfill and the area limited by the range of piezometers as the exclusive test area. To choose the optimal test area, representativity indicator was calculated also for the monitoring network around waste landfills, including the buffer network behind the piezometers. The difference in the values of the representativity indicator for subsequent variants is astounding. The representativity index for the same monitoring network is about 20 % higher if we consider the test area limited by external piezometers, and higher by another 20 %, taking into account the 95-m buffer zone behind piezometers. Due to increase of the representativity index value with a different width of buffer zone, the mathematical calculations of the monitoring network’s representativeness should be supported by an analysis of the geological structure and hydrogeological conditions occurring in the analyzed area