SummaryDespite their growing popularity as models of visual functions, it remains unclear whether rodents are capable of deploying advanced shape-processing strategies when engaged in visual object recognition. In rats, for instance, pattern vision has been reported to range from mere detection of overall object luminance to view-invariant processing of discriminative shape features. Here we sought to clarify how refined object vision is in rodents, and how variable the complexity of their visual processing strategy is across individuals. To this aim, we measured how well rats could discriminate a reference object from 11 distractors, which spanned a spectrum of image-level similarity to the reference. We also presented the animals with random variations of the reference, and processed their responses to these stimuli to derive subject-specific models of rat perceptual choices. Our models successfully captured the highly variable discrimination performance observed across subjects and object conditions. In particular, they revealed that the animals that succeeded with the most challenging distractors were those that integrated the wider variety of discriminative features into their perceptual strategies. Critically, these strategies were largely preserved when the rats were required to discriminate outlined and scaled versions of the stimuli, thus showing that rat object vision can be characterized as a transformation-tolerant, feature-based filtering process. Overall, these findings indicate that rats are capable of advanced processing of shape information, and point to the rodents as powerful models for investigating the neuronal underpinnings of visual object recognition and other high-level visual functions.

Twenty-first century projections for the Mediterranean water properties have been analyzed using the largest ensemble of regional climate models (RCMs) available up to now, the Med-CORDEX ensemble. It is comprised by 25 simulations, 10 historical and 15 scenario projections, from which 11 are ocean-atmosphere coupled runs and 4 are ocean forced simulations. Three different emissions scenarios are considered: RCP8.5, RCP4.5 and RCP2.6. All the simulations agree in projecting a warming across the entire Mediterranean basin by the end of the century as a result of the decrease of heat losses to the atmosphere through the sea surface and an increase in the net heat input through the Strait of Gibraltar. The warming will affect the whole water column with higher anomalies in the upper layer. The temperature change projected by the end of the century ranges between 0.81 and 3.71 °C in the upper layer (0-150 m), between 0.82 and 2.97 °C in the intermediate layer (150-600 m) and between 0.15 and 0.18 °C in the deep layer (600 m-bottom). The intensity of the warming is strongly dependent on the choice of emission scenario and, in second order, on the choice of Global Circulation Model (GCM) used to force the RCM. On the other hand, the local structures reproduced by each simulation are mainly determined by the regional model and not by the scenario or the global model. The salinity also increases in all the simulation due to the increase of the freshwater deficit (i.e. the excess of evaporation over precipitation and river runoff) and the related increase in the net salt transport at the Gibraltar Strait. However, in the upper layer this process can be damped or enhanced depending upon the characteristics of the inflowing waters from the Atlantic. This, in turn, depends on the evolution of salinity in the Northeast Atlantic projected by the GCM. Thus a clear zonal gradient is found in most simulations with large positive salinity anomalies in the eastern basin and a freshening of the upper layer of the western basin in most simulations. The salinity changes projected for the whole basin range between 0 and 0.34 psu in the upper layer, between 0.08 and 0.37 psu in the intermediate layer and between − 0.05 and 0.33 in the deep layer. These changes in the temperature and salinity modify in turn the characteristics of the main water masses as the new waters become saltier, warmer and less dense along the twenty-first century. There is a model consensus that the intensity of the deep water formation in the Gulf of Lions is expected to decrease in the future. The rate of decrease remains however very uncertain depending on the scenario and model chosen. At the contrary, there is no model consensus concerning the change in the intensity of the deep water formation in the Adriatic Sea and in the Aegean Sea, although most models also point to a reduction.

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Changes in 7 climate indices related to temperature or precipitation in Serbia were estimated for the reference period and for the future period 2071-2100, as derived from the results of the coupled regional climate model EBU-POM. In order to verify the appropriateness of the EBU-POM to simulate regional climate in the future, changes in the indices of intensive events were studied on the basis of the model data and daily series of temperature and precipitation observations from 17 meteorological stations in Serbia for the reference period. The results show an overall increase in the surface air temperature of about 2 and 4°C and a decrease in seasonal precipitation sums of about 13 and 6 mm for the A1B and A2 scenarios, respectively. It is likely that the number of days with absolute maximum temperature > 30°C (tropical days) will increase, while the total number of days with absolute minimum temperature < 0°C (frost days) will decrease in the future. A shorter duration of the frost period and a longer duration of dry and vegetation periods over the Serbian region is expected. KEY WORDS: Climate indices · Regional climate model · A1B scenario · A2 scenario · Serbia Resale or republication not permitted without written consent of the publisherClim Res 49: [73][74][75][76][77][78][79][80][81][82][83][84][85][86] 2011 The changes in climate extremes in the Mediterranean basin are seen in the increase in heavy precipitation and rise in extreme temperatures (Goubanova & Li 2007). Recently, Gao & Giorgi (2008) showed a widespread decrease in winter precipitation over most of the EM and warming during summer over the Balkans and western Turkey (5-6°) for future climate conditions (2071-2100) under the emission scenarios A2 and B2. Önol & Semazzi (2009), using the ICTP-RegCM3, investigated the role of global warming in modulating the future climate for the time frame 2071-2100 based on the A2 scenario over the EM. The major results were that, during summer, temperatures will increase by about 7°C over the Balkan countries (including Serbia), while changes for the rest of the region will be within the range of 3-4°C.To analyze events far from the mean climate range, but more likely to occur than outlying extremes, various precipitation and temperature indices have been introduced. They have been used to evaluate the present climate, starting with the work of Karl et al. (1996). Such work has been continued by, e.g., Frich et al. (2002) and Alexander et al. (2006). Klein Tank & Können (2003), Kostopoulou & Jones (2005), and Moberg et al. (2006) have focused on regional climate changes for the present climate. But climate indices can also be very helpful in indicating the consequences of various scenarios of climate change. Meehl et al. (2004), analyzing global simulations of the NCAR/Energy Parallel Climate Model for the climate of the 20th and 21st centuries found a general decrease in the number of frost days. Oikonomou et al. (2008) found longer dry spells, with reduced rainfall intensity over the EM for...

ABSTRACT:We considered shifts in the Köppen climate zones and the corresponding impact on the crop yields in Serbia by comparing (1) the results of downscaling with the ECMWF Hamburg Atmospheric Model 5 (ECHAM5) and regional Eta Belgrade University (EBU)-Princeton Ocean Model (POM) model for the A1B and A2 scenarios over 2001-2030 and 2071-2100 and (2) the present climate simulations for the period 1961−1990. We analyzed the EBU-POM regional climate model complexity by calculating the corresponding metrics. The yields of winter wheat, maize and soybeans were evaluated with the Decision Support System for Agrotechnology Transfer (DSSAT) model.In the future, the Köppen climate zones of Serbia will shift in coverage percentage and altitude from the present climate simulations toward warmer and drier climate zones. The calculated climate indices feature changes in the following parameters: increases in the mean annual temperature, growing season temperature, number of growing degree days (higher than 5 ∘ C) and the frequency of tropical days; and decreases in the mean annual precipitation, growing season precipitation and frequency of frost days. Yields of crops (winter wheat, maize and soybeans) will increase on average under both scenarios, with the exception of maize in non-irrigated conditions and under the A2 scenario.