Is behavioral ecology important for understanding and predicting population dynamics?

Population ecology is a discipline that studies changes in the number and composition (age, sex) of the individuals that form a population. Many of the mechanisms that generate these changes are associated with individual behavior, for example how individuals defend their territories, find mates or disperse. Therefore, it is important to model population dynamics considering the potential influence of behavior on the modeled dynamics. This study illustrates the diversity of behaviors that influence population dynamics describing several methods that allow integrating behavior into population models and range from simpler models that only consider the number of individuals to complex individual-based models that capture great levels of detail. A series of examples shows the importance of explicitly considering behavior in population modeling to avoid reaching erroneous conclusions. This integration is particularly relevant for conservation, as incorrect predictions regarding the dynamics of populations of conservation interest can lead to inadequate assessment and management. Improved predictions can favor effective protection of species and better use of the limited financial and human conservation resources

One strategy does not fit all: determinants of urban adaptation in mammals

Urbanisation exposes wildlife to new challenging conditions and environmental pressures. Some mammalian species have adapted to these novel environments, but it remains unclear which characteristics allow them to persist. To address this question, we identified 190 mammals regularly recorded in urban settlements worldwide, and used phylogenetic path analysis to test hypotheses regarding which behavioural, ecological and life history traits favour adaptation to urban environments for different mammalian groups. Our results show that all urban mammals produce larger litters; whereas other traits such as body size, behavioural plasticity and diet diversity were important for some but not all taxonomic groups. This variation highlights the idiosyncrasies of the urban adaptation process and likely reflects the diversity of ecological niches and roles mammals can play. Our study contributes towards a better understanding of mammal association to humans, which will ultimately allow the design of wildlife-friendly urban environments and contribute to mitigate human-wildlife conflicts

Temporal changes of the flare activity of Proxima Cen

We study temporal variations of the emission lines of Halpha, Hepsilon, H and K Ca II, D1 and D2 Na I, 4026 and 5876 A He I in the HARPS spectra of Proxima Centauri across an extended time of 13.2 years, from May 27, 2004, to September 30, 2017. Aims. We analyse the common behaviour and differences in the intensities and profiles of different emission lines in flare and quiet modes of Proxima activity. Methods. We compare the pseudo-equivalent widths (pEW) and profiles of the emission lines in the HARPS high-resolution (R ~ 115,000) spectra observed at the same epochs. Results. All emission lines show variability with a timescale of at least 10 min. The strength of all lines except He I 4026 A correlate with \Halpha. During strong flares the `red asymmetry' appears in the Halpha emission line indicating the infall of hot condensed matter into the chromosphere with velocities greater than 100 km/s disturbing chromospheric layers. As a result, the strength of the Ca II lines anti-correlates with Halpha during strong flares. The He I lines at 4026 and 5876 A appear in the strong flares. The cores of D1 and D2 Na I lines are also seen in emission. During the minimum activity of Proxima Centauri, Ca II lines and Hepsilon almost disappear while the blue part of the Na I emission lines is affected by the absorption in the extending and condensing flows. Conclusions. We see different behaviour of emission lines formed in the flare regions and chromosphere. Chromosphere layers of Proxima Cen are likely heated by the flare events; these layers are cooled in the `non-flare' mode. The self-absorption structures in cores of our emission lines vary with time due to the presence of a complicated system of inward and outward matter flows in the absorbing layers.Comment: 22 pages, 12 Figures, accepted by A

Fluctuations in a coupled-oscillator model of the cardiovascular system

We present a model of the cardiovascular system (CVS) based on a system of coupled oscillators. Using this approach we can describe several complex physiological phenomena that can have a range of applications. For instance, heart rate variability (HRV), can have a new deterministic explanation. The intrinsic dynamics of the HRV is controlled by deterministic couplings between the physiological oscillators in our model and without the need to introduce external noise as is commonly done. This new result provides potential applications not only for physiological systems but also for the design of very precise electronic generators where the frequency stability is crucial. Another important phenomenon is that of oscillation death. We show that in our CVS model the mechanism leading to the quenching of the oscillations can be controlled, not only by the coupling parameter, but by a more general scheme. In fact, we propose that a change in the relative current state of the cardiovascular oscillators can lead to a cease of the oscillations without actually changing the strength of the coupling among them. We performed real experiments using electronic oscillators and show them to match the theoretical and numerical predictions. We discuss the relevance of the studied phenomena to real cardiovascular systems regimes, including the explanation of certain pathologies, and the possible applications in medical practice

Dynamic analysis using finite elements to calculate the critical wear section of the contact wire in suburban railway overhead conductor rails

The purpose of this study is to determine the critical wear levels of the contact wire of the catenary on metropolitan lines. The study has focussed on the zones of contact wire where localised wear is produced, normally associated with the appearance of electric arcs. To this end, a finite element model has been developed to study the dynamics of pantograph-catenary interaction. The model includes a zone of localised wear and a singularity in the contact wire in order to simulate the worst case scenario from the point of view of stresses. In order to consider the different stages in the wire wear process, different depths and widths of the localised wear zone were defined. The results of the dynamic simulations performed for each stage of wear let the area of the minimum resistant section of the contact wire be determined for which stresses are greater than the allowable stress. The maximum tensile stress reached in the contact wire shows a clear sensitivity to the size of the local wear zone, defined by its width and depth. In this way, if the wear measurements taken with an overhead line recording vehicle are analysed, it will be possible to calculate the potential breakage risk of the wire. A strong dependence of the tensile forces of the contact wire has also been observed. These results will allow priorities to be set for replacing the most critical sections of wire, thereby making maintenance much more efficient. The results obtained show that the wire replacement criteria currently borne in mind have turned out to be appropriate, although in some wear scenarios these criteria could be adjusted even more, and so prolong the life cycle of the contact wire

A system of three transiting super-Earths in a cool dwarf star

We present the detection of three super-Earths transiting the cool star LP415-17, monitored by K2 mission in its 13th campaign. High resolution spectra obtained with HARPS-N/TNG showed that the star is a mid-late K dwarf. Using spectral synthesis models we infer its effective temperature, surface gravity and metallicity and subse- quently determined from evolutionary models a stellar radius of 0.58 R Sun. The planets have radii of 1.8, 2.6 and 1.9 R Earth and orbital periods of 6.34, 13.85 and 40.72 days. High resolution images discard any significant contamination by an intervening star in the line of sight. The orbit of the furthest planet has radius of 0.18 AU, close to the inner edge of the habitable zone. The system is suitable to improve our understanding of formation and dynamical evolution of super-Earth systems in the rocky - gaseous threshold, their atmospheres, internal structure, composition and interactions with host stars.Comment: Accepted for publication in MNRAS Letter