Prediction of severe thunderstorm events with ensemble deep learning and radar data

The problem of nowcasting extreme weather events can be addressed by applying either numerical methods for the solution of dynamic model equations or data-driven artificial intelligence algorithms. Within this latter framework, the most used techniques rely on video prediction deep learning methods which take in input time series of radar reflectivity images to predict the next future sequence of reflectivity images, from which the predicted rainfall quantities are extrapolated. Differently from the previous works, the present paper proposes a deep learning method, exploiting videos of radar reflectivity frames as input and lightning data to realize a warning machine able to sound timely alarms of possible severe thunderstorm events. The problem is recast in a classification one in which the extreme events to be predicted are characterized by a an high level of precipitation and lightning density. From a technical viewpoint, the computational core of this approach is an ensemble learning method based on the recently introduced value-weighted skill scores for both transforming the probabilistic outcomes of the neural network into binary predictions and assessing the forecasting performance. Such value-weighted skill scores are particularly suitable for binary predictions performed over time since they take into account the time evolution of events and predictions paying attention to the value of the prediction for the forecaster. The result of this study is a warning machine validated against weather radar data recorded in the Liguria region, in Italy

The drivers and functions of rock juggling in otters

This is the final version. Available on open access from the Royal Society via the DOI in this recordData accessibility: Data and code for rock juggling frequency, hunger and food puzzles can be accessed through the Dryad Digital Repository: https://doi.org/10.5061/dryad.rn8pk0p64. Tables of post hoc test results for puzzle order have been uploaded as part of the electronic supplementary material.Object play refers to the seemingly non-functional manipulation of inanimate items when in a relaxed state. In juveniles, object play may help develop skills to aid survival. However, why adults show object play remains poorly understood. We studied potential drivers and functions of the well-known object play behaviour of rock juggling in Asian small-clawed (Aonyx cinereus) and smooth-coated (Lutrogale perspicillata) otters. These are closely related species, but Asian small-clawed otters perform extractive foraging movements to exploit crabs and shellfish while smooth-coated otters forage on fish. We thus predicted that frequent rock jugglers might be better at solving extractive foraging puzzles in the first species, but not the latter. We also assessed whether species, age, sex and hunger correlated with rock juggling frequency. We found that juvenile and senior otters juggled more than adults. However, rock juggling frequency did not differ between species or sexes. Otters juggled more when ‘hungry’, but frequent jugglers did not solve food puzzles faster. Our results suggest that rock juggling may be a misdirected behaviour when hungry and may facilitate juveniles’ motor development, but it appears unrelated to foraging skills. We suggest future studies to reveal the ontogeny, evolution and welfare implications of this object play behaviour.Royal Societ

Route to non-Gaussian statistics in convective turbulence

Motived by the work of Li and Meneveau (Phys. Rev. Lett. 95, 164502 (2005)), we propose and solve a model for the Lagrangian evolution of both longitudinal and transverse velocity and temperature increments for Boussinesq convection. From this model, the short-time evolution of an initially imposed Gaussian joint probability density function (PDF) of both velocity and temperature increments is computed analytically and the trend to non-Gaussian statistics shown in a quantitative way. Predictions for moments of the joint PDF are obtained and their behavior analyzed with respect to known experimental and numerical results. The obtained results do not depend on the model free parameters, a fact in favor of their robustness

Non-invasive Multidisciplinary Approach to the Study of Reproduction and Calf Development in Bottlenose Dolphin (Tursiops truncatus): The Rimini Delfinario Experience

Reproduction is a fundamental biological process that occurs only when all other vital needs are satisfied. In cetaceans reproduction takes place completely in water. From courtship and mating to calf weaning, every step of the reproductive process occurs under the water\u2019s surface. This complicates data acquisition in wild populations, making captive observations a useful complement to wild studies. By allowing close examination of phenomena, studies in captive environments are able to collect long-term data on known subjects, and sample, in detail, complete behavioural sequences while monitoring physiological or acoustic patterns. Studies of reproduction in bottlenose dolphins (Tursiops truncatus) were initiated at Rimini Delfinario (Italy) in 1995. Four bottlenose dolphin births (in 1995, 1997, 2003 and 2007) have occurred since the start of this research. Due to evidence suggesting that mother and calf associations are closest in the first year of the calf\u2019s life, mothers and calves were studied from birth to the end of the first year. Beginning in 1997, studies encompassed the behaviour and physiology of dolphin mothers during gestation. Here, we report results of interdisciplinary studies of reproductive processes in bottlenose dolphins, including aspects of behaviour, physiology, endocrinology, and acoustics. In an effort to reduce the potential for bias brought about by invasive sampling, we investigated methods of sampling expired air from the dolphin\u2019s blowhole as a means of monitoring steroid hormone levels. In summary, our research combines an interdisciplinary network with specialized professional alliances and offers a potentially crucial approach to the biological aspects of reproduction. At the same time, research findings presented here aim to help bridge the gap existing between captive and wild studies in favor of a common aim of conservation biology

Droplet condensation in two-dimensional Bolgiano turbulence

The evolution of microdroplets transported by a turbulent flow is considered. Droplets surrounded by moist air are able to grow by diffusion of water vapour on their surface. A two-dimensional model of dry Boussinesq thermal convection is considered in which the turbulent velocity field is driven by a temperature gradient. The evolution of the velocity, temperature, vapour fields and of droplet trajectories and radii is analysed by means of high-resolution direct numerical simulations. Despite the fact that the environment becomes drier and drier, a mean growth of droplets is obtained. The mechanism identified is based on the presence of correlations between the vapour field and droplet trajectories. Besides, a spreading of size distribution is observed, with the formation of droplets with very different sizes. Improvements with respect to previous models are discussed

Blowhole hormonal analysis: a new approach to the study of tursiops truncatus pregnancy?

INTRODUCTION Hormones and behaviour are reciprocally influenced. Monitoring hormones levels can therefore provide insights into the mechanistic aspects of behaviour. Hormones are usually extracted from blood samples or saliva, urine and faeces. In cetaceans, an alternative source may be found in blowhole samples, which can be collected non-invasively. Given the current scientific knowledge on pregnancy endocrinology in dolphins, specific aims of this trail were a) to set up and validate progesterone (P4) and cortisol determination procedures from blowhole samples and b) to determine the concentration and profile of progesterone and cortisol during Tursiops truncatus pregnancy. MATERIAL AND METHODS The study was conducted in the Rimini Delfinario (Italy) on a female monitored from July to September 2003 during the last three months of gestation. The observations were made once a week until the final week before delivery when samples were taken on three alternative days. The bottlenose dolphin was trained to blow into polypropylene sterile bottles with a screw closure. The samples were stored at –20°C until assayed. Concentrations of steroid hormones were determined by validated radioimmunoassays (Seren et al., 1974; Tamanini et al., 1983). RESULTS AND DISCUSSION Progesterone concentrations during the last 12 weeks of gestation always remained high and didn’t change throughout the observed period. However, during the final week progesterone values gradually decreased as the birth date approached and continued to fall until reaching the minimum 40 days after the event. As for cortisol, its concentrations were low until 10 days before the delivery when, as expected, they started to dramatically rise until reaching the maximum the day before the birth. In conclusion, since these results are analogous to those obtained from blood serum and milk in the same species and in other mammals under similar physiological conditions, blowhole samples could represent a suitable biological material in order to detect and quantify by RIA progesterone and cortisol levels during pregnancy. At the same time, the sampling method is easy to be applied and absolutely non-invasive for the animals