Spatial multi-criteria decision analysis to predict suitability for African swine fever endemicity in Africa

Background African swine fever (ASF) is endemic in several countries of Africa and may pose a risk to all pig producing areas on the continent. Official ASF reporting is often rare and there remains limited awareness of the continent-wide distribution of the disease. In the absence of accurate ASF outbreak data and few quantitative studies on the epidemiology of the disease in Africa, we used spatial multi-criteria decision analysis (MCDA) to derive predictions of the continental distribution of suitability for ASF persistence in domestic pig populations as part of sylvatic or domestic transmission cycles. In order to incorporate the uncertainty in the relative importance of different criteria in defining suitability, we modelled decisions within the MCDA framework using a stochastic approach. The predictive performance of suitability estimates was assessed via a partial ROC analysis using ASF outbreak data reported to the OIE since 2005. Results Outputs from the spatial MCDA indicate that large areas of sub-Saharan Africa may be suitable for ASF persistence as part of either domestic or sylvatic transmission cycles. Areas with high suitability for pig to pig transmission (‘domestic cycles’) were estimated to occur throughout sub-Saharan Africa, whilst areas with high suitability for introduction from wildlife reservoirs (‘sylvatic cycles’) were found predominantly in East, Central and Southern Africa. Based on average AUC ratios from the partial ROC analysis, the predictive ability of suitability estimates for domestic cycles alone was considerably higher than suitability estimates for sylvatic cycles alone, or domestic and sylvatic cycles in combination. Conclusions This study provides the first standardised estimates of the distribution of suitability for ASF transmission associated with domestic and sylvatic cycles in Africa. We provide further evidence for the utility of knowledge-driven risk mapping in animal health, particularly in data-sparse environments.</p

Investigation of the machining process of spheroidal cast iron using cubic boron nitride (CBN) tools

This paper presents the experimental results of the turning of spheroidal iron (EN-GJS-500-7 grade) using L-CBN tools. The cutting process can be classified as a High Performance Cutting (HPC) due to a relatively high material removal rate of about 190 cm3/min. The investigations performed include fundamental process quantities and machined surface characteristics, i.e. componential cutting forces, specific cutting energy, average and maximum values of cutting temperature as well as temperature distribution in the cutting zone, tool wear progress visualized by appropriate wear curves and 2D/3D surface roughness parameters

Behavioral Interactions Of Opioid Agonists And Antagonists With Serotonergic Systems

Morphine interacts with brain serotonergic (5-HT) systems; these systems have been implicated in morphine analgesia and dependence (see Cervo et al., 1981). The 5-HT agonist quipazine induces analgesia in rats that is attenuated by naloxone and 5-HT antagonists (Minnema et al., 1980; Samanin et al., 1976). Behavioral disruption by the hallucinogens LSD, DMT and mescaline, mediated primarily through brain 5-HT effects (Rech and Commissaris, 1982), is potentiated by naloxone and naltrexone (Commissaris et al., 1980; Ruffing and Domino, 1981) and is variably antagonized or potentiated by morphine and methadone (Ruffing and Domino, 1981). Cyclazocine causes a disruption of operant behavior similar to that of the hallucinogens which is reversed in part by nalozone and the 5-HT antagonist metergoline, and to a greater extent by the combination of maloxone and metergoline (Henck et al., 1983). These studies indicate that indole and phenethylamine hallucinogens interact to some extent with brain opioid mechanisms as well as brain 5-HT components, whereas opioid drugs influence behavior in part by actions on 5-HT systems. We have extended these drug studies in an attempt to characterize interactions with 5-HT mechanisms and to identify the various types of opioid receptors involved

Naimark-Sacker Bifurcations in Linearly Coupled Quadratic Maps

We report exact analytical expressions locating the $0\to1$, $1\to2$ and $2\to4$ bifurcation curves for a prototypical system of two linearly coupled quadratic maps. Of interest is the precise location of the parameter sets where Naimark-Sacker bifurcations occur, starting from a non-diagonal period-2 orbit. This result is the key to understand the onset of synchronization in networks of quadratic maps.Comment: 6 pages, 3 figures (1 in color), submitted to Physica

Enhancing Performance of Nonfullerene Acceptors via Side-Chain Conjugation Strategy

A side-chain conjugation strategy in the design of nonfullerene electron acceptors is proposed, with the design and synthesis of a side-chain-conjugated acceptor (ITIC2) based on a 4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b′]di(cyclopenta-dithiophene) electron-donating core and 1,1-dicyanomethylene-3-indanone electron-withdrawing end groups. ITIC2 with the conjugated side chains exhibits an absorption peak at 714 nm, which redshifts 12 nm relative to ITIC1. The absorption extinction coefficient of ITIC2 is 2.7 × 105m−1 cm−1, higher than that of ITIC1 (1.5 × 105m−1 cm−1). ITIC2 exhibits slightly higher highest occupied molecular orbital (HOMO) (−5.43 eV) and lowest unoccupied molecular orbital (LUMO) (−3.80 eV) energy levels relative to ITIC1 (HOMO: −5.48 eV; LUMO: −3.84 eV), and higher electron mobility (1.3 × 10−3 cm2 V−1 s−1) than that of ITIC1 (9.6 × 10−4 cm2 V−1 s−1). The power conversion efficiency of ITIC2-based organic solar cells is 11.0%, much higher than that of ITIC1-based control devices (8.54%). Our results demonstrate that side-chain conjugation can tune energy levels, enhance absorption, and electron mobility, and finally enhance photovoltaic performance of nonfullerene acceptors

the path to silicon-singlet fission heterojunction devices

Singlet exciton fission is an exciton multiplication process that occurs in certain organic materials, converting the energy of single highly-energetic photons into pairs of triplet excitons. This could be used to boost the conversion efficiency of crystalline silicon solar cells by creating photocurrent from energy that is usually lost to thermalisation. An appealing method of implementing singlet fission with crystalline silicon is to incorporate singlet fission media directly into a crystalline silicon device. To this end, we developed a solar cell that pairs the electron-selective contact of a high-efficiency silicon heterojunction cell with an organic singlet fission material, tetracene, and a PEDOT:PSS hole extraction layer. Tetracene and n-type crystalline silicon meet in a direct organic–inorganic heterojunction. In this concept the tetracene layer selectively absorbs blue-green light, generating triplet pairs that can dissociate or resonantly transfer at the organo-silicon interface, while lower-energy light is transmitted to the silicon absorber. UV photoemission measurements of the organic–inorganic interface showed an energy level alignment conducive to selective hole extraction from silicon by the organic layer. This was borne out by current–voltage measurements of devices subsequently produced. In these devices, the silicon substrate remained well-passivated beneath the tetracene thin film. Light absorption in the tetracene layer created a net reduction in current for the solar cell, but optical modelling of the external quantum efficiency spectrum suggested a small photocurrent contribution from the layer. This is a promising first result for the direct heterojunction approach to singlet fission on crystalline silicon

Efficient Light Management by Textured Nanoimprinted Layers for Perovskite Solar Cells

Inorganic organic perovskites like methylammonium lead iodide have proven to be an effective class of materials for fabricating efficient solar cells. To improve their performance, light management techniques using textured surfaces, similar to those used in established solar cell technologies, should be considered. Here, we apply a light management foil created by UV nanoimprint lithography on the glass side of an inverted p i n perovskite solar cell with 16.3 efficiency. The obtained 1 mA cm 2 increase in the short circuit current density translates to a relative improvement in cell performance of 5 , which results in a power conversion efficiency of 17.1 . Optical 3D simulations based on experimentally obtained parameters were used to support the experimental findings. A good match between the simulated and experimental data was obtained, validating the model. Optical simulations reveal that the main improvement in device performance is due to a reduction in total reflection and that relative improvement in the short circuit current density of up to 10 is possible for large area devices. Therefore, our results present the potential of light management foils for improving the device performance of perovskite solar cells and pave the way for further use of optical simulations in the field of perovskite solar cell