A computational model approach to assess the effect of climate change on the growth and development of tadpoles

All of the environmental conditions in nature act on an organism simultaneously. However, in experimental studies of the factors influencing metamorphosis, each factor needs to be examined individually in order to disentangle its specific effects. However, it is challenging to then build properly integrated models which include data on all of the different factors evaluated in different experiments. This study set out to develop a predictive model which could synthesize the results of several experiments on survival, development and growth of Natterjack toad (Epidalea calamita) tadpole guilds. The proposed Population Dynamic P System (PDP) model enables estimates of growth and development during the larval phase, under different environmental conditions, weather conditions, predator density, and pond characteristics and management. The architecture of the model allows the inclusion of an indefinite number of parameters and interactions, with all inputs interacting in parallel, and enables solutions to complex modeling approaches. Using the model with a range of field data, we found that the importance of predation pressure on Natterjack toad tadpole guilds exceeds the potential effects of variations in temperature and precipitation. The impact of introduced invasive predators therefore arguably poses the greatest threat to this species. This type of model holds promise as a reliable management and conservation tool for this and other species, especially where interactions between environmental factors make the impacts of individual factors difficult to predict

J. A. Goytisolo : Barcelona, entre Iulia i Julia

Publicat a Diari de Barcelona

A P System Modeling an Ecosystem Related to the Bearded Vulture

The Bearded Vulture is one of the rarest raptors in Europe and it is an endangered species. In this paper, we present a model of an ecosystem related with the Bearded Vulture which is located in the Catalan Pyrenees, by using P systems. The population dynamics constituted by the Bearded Vulture (that feeds almost exclusively on bones) and other five subfamilies that provide the bones they feed on, is studied. P systems provide a high level computational modeling framework which integrates the structural and dynamical aspects of ecosystems in a comprehensive and relevant way. P systems explicitly represent the discrete character of the components of an ecosystem by using rewriting rules on multisets of objects which represent individuals of the population and bones. The inherent stochasticity and uncertainty in ecosystems is captured by using probabilistic strategies. In order to give an experimental validation of the P system designed, we have constructed a simulator that allows us to analyze the evolution of the ecosystem with different initial conditions.Ministerio de Educación y Ciencia TIN2006-13425Junta de Andalucía TIC 58

A P System Based Model of an Ecosystem of Some Scavenger Birds

The Bearded Vulture (Gypaetus Barbatus) is an endangered species in Eu- rope that feeds almost exclusively on bone remains provided by wild and domestic ungu- lates. In [1], we presented a P system in order to study the evolution of these species in the Pyrenees (NE Spain). Here, we present a new model that overcomes some limitations of the previous work incorporating other scavenger species (predatory) and additional prey species that provide food for the scavenger intraguild and interact with the Bearded Vulture in the ecosystem. After the validation, the new model can be a useful tool for the study of the evolution and management of the ecosystem. P systems provide a high level computational modelling framework which integrates the structural and dynamical aspects of ecosystems in a compressive and relevant way. The inherent randomness and uncertainty in ecosystems is captured by using probabilistic strategies.Ministerio de Educación y Ciencia TIN2006-13425Junta de Andalucía P08–TIC-0420

P System Based Model of an Ecosystem of the Scavenger Birds

The Bearded Vulture (Gypaetus Barbatus) is an endangered species in Europe that feeds almost exclusively on bone remains provided by wild and domestic ungulates. In, we presented a P system in order to study the evolution of these species in the Pyrenees (NE Spain). Here, we present a new model that overcomes some limitations of the previous work incorporating other scavenger species (predatory) and additional prey species that provide food for the scavenger intraguild and interact with the Bearded Vulture in the ecosystem. After the validation, the new model can be a useful tool for the study of the evolution and management of the ecosystem. P systems provide a high level computational modelling framework which integrates the structural and dynamical aspects of ecosystems in a compressive and relevant way. The inherent stochasticity and uncertainty in ecosystems is captured by using probabilistic strategies.Ministerio de Educación y Ciencia TIN2006–13425Junta de Andalucía P08-TIC-0420

Synoptic weather patterns conducive to compound extreme rainfall–wave events in the NW Mediterranean

The NW Mediterranean coast is highly susceptible to the impacts of extreme rainstorms and coastal storms, which often lead to flash floods, coastal erosion, and flooding across a highly urbanised territory. Often, these storms occur simultaneously, resulting in compound events that intensify local impacts when they happen in the same location or spread impacts across the territory when they occur in different areas. These multivariate and spatially compound events present significant challenges for risk management, potentially overwhelming emergency services. In this study, we analysed the prevailing atmospheric conditions during various types of extreme episodes, aiming to create the first classification of synoptic weather patterns (SWPs) conducive to compound events involving heavy rainfall and storm waves in the Spanish NW Mediterranean. To achieve this, we developed a methodological framework that combines an objective synoptic classification method based on principal component analysis and k-means clustering with a Bayesian network. This methodology was applied to a dataset comprising 562 storm events recorded over 30 years, including 112 compound events. First, we used the framework to determine the optimal combination of domain size, classification variables, and number of clusters based on the synoptic skill to replicate local-scale values of daily rainfall and significant wave height. Subsequently, we identified SWPs associated with extreme compound events, which are often characterised by upper-level lows and trough structures in conjunction with Mediterranean cyclones, resulting in severe to extreme coastal storms combined with convective systems. The obtained classification demonstrated strong skill, with scores exceeding 0.4 when considering factors like seasonality or the North Atlantic Oscillation. These findings contribute to a broader understanding of compound terrestrial–maritime extreme events in the study area and have the potential to aid in the development of effective risk management strategies.</p

Modeling Population Growth of Pyrenean Chamois (Rupicapra p. pyrenaica) by Using P-Systems

P systems provide a high level computational modeling framework which integrates the structural and dynamic aspects of ecosystems in a comprehensive and relevant way. In previous works, several ecosystems modeled by using P systems were presented. The good results obtained encourage us to study new ecosystems such as the one presented in this paper. Pyrenean Chamois (Rupicapra p. pyrenaica) is an ungulate species inhabiting the Catalan Pyrenees. In recent years, several diseases have caused a drastic decrease in the number of individuals. Since they provide significant economic contributions in the area and constitutes an important food resource for obligate and facultative scavengers, it is very interesting to provide a model in order to facilitate the management of their ecosystems

A computational modeling for real ecosystems based on P systems

In this paper, a P systems based general framework for modeling ecosystems dynamics is presented. Particularly, ecosystems are specified by means of multienvironment P systems composed of a finite number of environments, each of them having an extended P system with active membranes. The semantics is of a probabilistic type and it is implemented by assigning each rule of the system a probabilistic constant which depends on the environment and the run time. As a case study, two real ecosystems are described: scavenger birds in the Catalan Pyrenees and the zebra mussel (Dreissena Polymorpha) in Ribarroja reservoir (Spain).Ministerio de Ciencia e Innovación TIN2009–13192Junta de Andalucía P08–TIC-0420

MATRIX16: A 16-Channel Low-Power TDC ASIC with 8 ps Time Resolution

This paper presents a highly configurable 16-channel TDC ASIC designed in a commercial 180 nm technology with the following features: time-of-flight and time-over-threshold measurements, 8.6 ps LSB, 7.7 ps jitter, 5.6 ps linearity error, up to 5 MHz of sustained input rate per channel, 9.1 mW of power consumption per channel, and an area of 4.57 mm2 . The main contributions of this work are the novel design of the clock interpolation circuitry based on a resistive interpolation mesh circuit and the capability to operate at different supply voltages and operating frequencies, thus providing a compromise between TDC resolution and power consumption. Keywords: TDC; time-to-digital converter; fast timing; PET; VLSI; ASIC; ToF; ToT; low power; frontend electronic