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Radiative transfer models used in remote sensing and hazard assessment of volcanic ash require knowledge of ash optical parameters. Here we characterize the bulk and glass compositions of a representative suite of volcanic ash samples with known complex refractive indices (n+ ik, where nis the real part and kis the imaginary part). Using a linear regression model, we develop a new parameterization allowing the complex refractive index of volcanic ash to be estimated from ash SiO2content or ratio of nonbridging oxygens to tetrahedrally coordinated cations (NBO/T). At visible wavelengths, ncorrelates better with bulk than with glass composition (both SiO2and NBO/T), and kcorrelates better with SiO2content than with NBO/T. Over a broader spectral range (0.4–19 μm), bulk correlates better than glass composition, and NBO/T generally correlates better than SiO2content for both parts of the refractive index. In order to understand the impacts of our new parameterization on satellite retrievals, we compared Infrared Atmospheric Sounding Interferometer satellite (wavelengths 3.62–15.5 μm) mass loading retrievals using our new approach with retrievals that assumed a generic (Eyjafjallajökull) ash refractive index. There are significant differences in mass loading using our calculated indices specific to ash type rather than a generic index. Where mass loadings increase, there is often improvement in retrieval quality (corresponding to cost function decrease). This new parameterization of refractive index variation with ash composition will help to improve remote‐sensing retrievals for the rapid identification of ash and quantitative analysis of mass loadings from satellite data on operational timescales. This study shows that refractive index correlates with bulk and glass major oxide compositions of volcanic ash over a broad spectral rangeA parameterization of complex refractive index is developed based on the silica content and NBO/T of volcanic ash using the correlation foundMass loading retrievals using the parameterization show significant differences compared to those using a generic complex refractive index

Airborne volcanic ash poses a significant danger to aircraft, but is difficult to quantify accurately using satellite data, while sulphur dioxide is much easier to detect accurately, but is much less of a direct hazard to aviation. This paper investigates the reliability of using SO2as a proxy for the location of volcanic ash, using an SO2retrieval from the Infrared Atmospheric Sounding Interferometer (IASI) and ash detections from IASI and the Advanced Along Track Scanning Radiometer (AATSR). Using a numerical “missed ash fraction” applied to the eruptions of Eyjafjallajökull in 2010 and Puyehue‐Cordón Caulle in 2011 reveals that the SO2flag typically misses ∼30% of the detectable ash. Furthermore, the missed ash fraction is found to be highly variable, both between the two eruptions and over the course of each eruption, with values of over 80% found on some days. The detection threshold of the AATSR ash flag is also investigated using radiative transfer calculations, allowing the threshold of the IASI flag to be inferred, and these are related to the ash contamination levels. SO2cannot be used as a proxy for the location of volcanic ash plumesFor aviation safety satellite detection of ash is not sufficient on its ownA quantitative comparison of ash and SO2collocation has been carried out

The remote sensing of volcanic ash plumes from space can provide a warning of an aviation hazard and knowledge on eruption processes and radiative effects. In this paper new algorithms are presented to provide volcanic plume properties from measurements by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), the Advanced Along Track Scanning Radiometer (AATSR) and the Spinning Enhanced Visible and Infrared Imager (SEVIRI). A challenge of remote sensing is to provide near-real-time methods to identify, and so warn of, the presence of volcanic ash. To achieve this, a singular vector decomposition method has been developed for the MIPAS instrument on board the Environmental Satellite. This method was applied to observations of the ash clouds from the eruptions of Nabro and the Puyehue–Cordón Caulle in 2011 and led to a sensitive volcanic signal flag which was capable of tracking changes in the volcanic signal spectra as the plume evolved. A second challenge for remote sensing is to identify the ash plume height. This is a critical parameter for the initialization of algorithms that numerically model the evolution and transport of a volcanic plume. As MIPAS is a limb sounder, the identification of ash also provides an estimate of height provided the plume is above about 6 km. This is complemented by a new algorithm, Stereo Ash Plume Height Retrieval Algorithm, that identifies plume height using the parallax between images provided by Along Track Scanning Radiometer-type instruments. The algorithm was tested on an image taken at 14:01 GMT on 6 June 2011 of the Puyehue–Cordón Caulle eruption plume and gave a height of 11.9±1.4 km, which agreed with the value derived from the location of the plume shadow (12.7±1.8 km). This plume height was similar to the height observed by MIPAS (12 ± 1.5 km) at 02:56 GMT on 6 June. The quantitative use of satellite imagery and the full exploitation of high-resolution spectral measurements of ash depends upon knowing the optical properties of the observed ash. Laboratory measurements of ash from the 1993 eruption of Mt Aso, Japan have been used to determine the refractive indices from 1 to 20 µm. These preliminary measurements have spectral features similar to ash values that have been used to date, albeit with slightly different positions and strengths of the absorption bands. The refractive indices have been used to retrieve ash properties (plume height, optical depth and ash effective radius) from AATSR and SEVIRI instruments using two versions of Oxford-RAL Retrieval of Aerosol and Cloud (ORAC) algorithm. For AATSR a new ash cloud type was used in ORAC for the analysis of the plume from the 2011 Eyjafjallajökull eruption. For the first c. 500 km of the plume ORAC gave values for plume height of 2.5–6.5 km, optical depth 1–2.5 and effective radius 3–7 µm, which are in agreement with other observations. A weakness of the algorithm occurs when underlying cloud invalidates the assumption of a single cloud layer. This is rectified in a modified version of ORAC applied to SEVIRI measurements. In this case an extra model of a cloud underlying the ash plume was included in the range of applied models. In cases where the plume overlay cloud, this new model worked well, showing good agreement with correlative Cloud–Aerosol Lidar with Orthogonal Polarization observations.

Conventional reinforcers phasically stimulate dopamine transmission in the nucleus accumbens shell. This property undergoes one-trial habituation consistent with a role of nucleus accumbens shell dopamine in associative learning. Experimental studies with place- and taste-conditioning paradigms confirm this role. Addictive drugs share with conventional reinforcers the property of stimulating dopamine transmission in the nucleus accumbens shell. This response, however, undergoes one-trial habituation in the case of conventional reinforcers but not of drugs. Resistance to habituation allows drugs to repetitively activate dopamine transmission in the shell upon repeated self-administration. This process abnormally facilitates associative learning, leading to the attribution of excessive motivational value to discrete stimuli or contexts predictive of drug availability. Addiction is therefore the expression of the excessive control over behavior acquired by drug-related stimuli as a result of abnormal strenghtening of stimulus-drug contingencies by nondecremental drug-induced stimulation of dopamine transmission in the nucleus accumbens shell.

Certain endogenously occurring 3α-hydroxylated, 5-reduced pregnane steroids act at a specific site on the GABAA receptor complex (GRC) to modulate the effects of GABA at its receptor. Modulators that potentiate GABA at the GABAA receptor often possess anxiolytic properties. The anxiolytic potential of four 5-reduced, 3α, 20-pregnanediols, differing only in the stereochemical orientation of the steroid A-ring and the 20-hydroxyl group, were tested in the Vogel test following intracerebroventricular (ICV) administration. The effects of these pregnanediols were compared to those of their 20-ketone analogues, 3α-hydroxy-5α-pregnan-20-one (3α,5α-P) and 3α-hydroxy-5β-pregnan-20-one (3α,5β-P). All four pregnanediols tested significantly enhanced punished drinking at doses ranging from 10 to 60 µg. The rank order of potency based on the minimum effective dose (MED) observed was 5α-pregnan-3α,20α-diol=5β-pregnan-3α,20α-diol > 5β-pregnan-3α,20β-diol > 5α-pregnan-3α,20β-diol. 3α,5β-P and 3α,5α-P enhanced punished responding when administered at 2.5 and 5 µg, respectively. 3β,5α-P which is inactive at the GRC was also inactive (up to 100 µg) in the Vogel test. The benzodiazepine control diazepam was efficacious when administered at 2.5 µg. 5α-Pregnan-3α,20α-diol was further tested in the mouse elevated plus-maze model following systemic administration where it was found to be active in a dose range of 10–40 mg/kg IP. These results raise the possibility that in addition to 3α,5α-P and 3α,5β-P, some of their endogenously occurring pregnanediol metabolites may also influence physiological processes related to anxiety via the GRC.

The effect of two 5HT3 antagonists, ICS 205-930 and MDL 72222, on drug-induced place aversion was studied in a two-compartment apparatus with a procedure including a pre-test for spontaneous preference. Naloxone (0.8 mg/kg SC), phencyclidine (2.5 mg/kg SC) and picrotoxin (2.0 mg/kg IP) paired with the preferred compartment elicited a significant place aversion. ICS 205-930 and MDL 72222 failed to modify spontaneous place preference when paired with both compartments. ICS 205-930 (30 µg/kg SC) paired with the preferred and, in other experiments, with the non-preferred compartment, also failed to modify spontaneous preference. ICS 205-930 (7.5, 15 and 30 µg/kg SC), paired with both compartments, dose-dependently reduced the place aversion induced by naloxone (0.8 mg/kg SC), phencyclidine (2.5 mg/kg SC) and picrotoxin (2.0 mg/kg IP). MDL 72222 (30 µg/kg SC) paired with both compartments had a similar effect. The result indicate that 5HT, via 5HT3 receptors, plays a role in the aversive properties of drug stimuli.

The effect of two potent and specific antagonists of 5HT3 receptors, ICS 205-930 and MDL 72222, on the reinforcing properties of amphetamine, morphine and nicotine was studied in rats. Durg-induced reinforcement was assessed by measuring drug-conditioned place preference. ICS 205-930 and MDL 72222 dose-dependently reduced the place preference induced by morphine (1.0 mg/kg SC). At doses of 0.030 mg/kg SC the two antagonists completely blocked morphine-induced place preference while doses of 0.015 mg/kg SC significantly reduced it. ICS 205-930 and MDL 72222 at doses of 0.030 mg/kg SC also prevented the place preference induced by nicotine (0.6 mg/kg SC). In contrast, ICS 205-930 and MDL 72222 up to doses of 0.030 mg/kg SC failed to modify the place preference elicited by amphetamine (1.0 mg/kg SC). The results indicate that 5HT3 receptors are specifically involved in the reinforcing properties of morphine and nicotine.

The influence of the D1 antagonist SCH 23390 on the motivational properties of rewarding (morphine, nicotine and diazepam) and aversive (naloxone, phencyclidine and picrotoxin) drugs was studied in the rat in a two-compartment place-conditioning paradigm, which included a pre-conditioning test for spontaneous place-preference. The specific D1 dopamine-receptor antagonist SCH 23390 (0.05 mg/kg SC), paired with both compartments or, separately, with the preferred or with the non-preferred compartment, failed to affect the spontaneous unconditioned preference of the animal. Pairing of morphine (1.0 mg/kg SC), nicotine (0.6 mg/kg SC) or diazepam (1.0 mg/kg IP) with the less preferred compartment induced significant preference for that compartment. Pairing of SCH 23390 (0.05 mg/kg SC) with both compartments completely blocked the place-preference induced by morphine, nicotine and diazepam. Naloxone (0.8 mg/kg SC), phencyclidine (2.5 mg/kg SC) or picrotoxin (2.0 mg/kg IP) paired with the preferred compartment elicited place-aversion. Pairing of SCH 23390 (0.05 mg/kg SC) with both compartments abolished also the place-aversion induced by naloxone, phencyclidine and picrotoxin. The results indicate that blockade of dopamine transmission blocks the motivational properties of rewarding as well as aversive stimuli. It is suggested that neuroleptics rather than simply blocking the rewarding impact of positive reinforcers (anhedonia, lack of pleasure) exert a more general influence on conditioned behaviour by blocking the affective impact of negative as well as positive reinforcers (apathy, lack of motivation).

AbstractA few DNA based approaches have been developed to trace animal products from the farm to the consumer “fork”. These approaches make use of the animal DNA that can be recovered during all steps of the production chain directly as part of the products that are obtained from them. This direct link between the animals and the products can be assessed using DNA markers like, for example, single nucleotide polymorphisms and microsatellites, for individual or population based (breed) traceability systems. However, these methods, in general, rely on the possibility to constitute banks of animal biological samples for critical/important steps of the production chain and analyse a large number of samples (individual traceability) or to identify breed/population multilocus informative markers or few specific mutations that can distinguish the breed/population of origin (breed traceability). Here we developed a new traceability and authentication system that makes use of the DNA contained in an added material to the animal originated products, establishing a link between alien DNA and the products, thus without the need to know/sample the animals that originated the products and having the possibility to operate at different levels in the production chain. The added material is of natural origin and can be or cannot be normally part of the final transformed animal products, but in all cases it does not alter the products themselves. We tested this new system in the dry-cured ham production chain using plant originated products (wheat flour) to mark/label the legs. The wheat flours, derived from unique lines (23) that were previously chosen and genetically characterized with a set of 7 specific microsatellites, were mixed to the ink commonly used to mark the green legs or to the fat preparation (whose recipe can include wheat or rice flour) used to grease the hams. The corresponding wheat DNA was identified after several months of seasoning on the hams by means of microsatellite analysis and the observed genotypes were always as expected from the wheat lines that were used to produce the tracers. This new system for product traceability and authentication revealed to be affordable and easy to apply to animal products and can be used to “label” the productions at different levels (consortium, the farm of origin of the animals, the year/month of production, etc.). Modifications of this system can be applied to several other food products. Patent pending.