Quiescent X-ray variability in the neutron star Be/X-ray transient GRO J1750-27

The Be/X-ray transient GRO J1750-27 exhibited a type-II (giant) outburst in 2015. After the source transited to quiescence, we triggered our multi-year Chandra monitoring programme to study its quiescent behaviour. The programme was designed to follow the cooling of a potentially heated neutron-star crust due to accretion of matter during the preceding outburst, similar to what we potentially have observed before in two other Be/X-ray transients, namely 4U 0115+63 and V 0332+53. However, unlike for these other two systems, we do not find any strong evidence that the neutron-star crust in GRO J1750-27 was indeed heated during the accretion phase. We detected the source at a rather low X-ray luminosity (~10^33 erg/s) during only three of our five observations. When the source was not detected it had very low-luminosity upper limits (<10^32 erg/s; depending on assumed spectral model). We interpret these detections and the variability observed as emission likely due to very low-level accretion onto the neutron star. We also discuss why the neutron-star crust in GRO J1750-27 might not have been heated while the ones in 4U 0115+63 and V 0332+53 possibly were.Comment: 13 pages, 6 figures, 5 tables. Accepted for A&

Gap inversion in one-dimensional Andreev crystals

We study a periodic arrangement of magnetic regions in a one-dimensional superconducting wire. Due to the local exchange field, each region supports Andreev bound states that hybridize forming Bloch bands in the subgap spectrum of what we call the Andreev crystal (AC). As an illustration, ACs with ferromagnetic and antiferromagnetic alignment of the magnetic regions are considered. We relate the spectral asymmetry index of a spin-resolved Hamiltonian to the spin polarization and identify it as the observable that quantifies the closing and reopening of the excitation gap. In particular, antiferromagnetic ACs exhibit a sequence of gapped phases separated by gapless Dirac phase boundaries. Heterojunctions between antiferromagnetic ACs in neighboring phases support spin-polarized bound states at the interface. In a close analogy to the charge fractionalization in Dirac systems with a mass inversion, we find a fractionalization of the interface spin.Comment: 6 pages, 4 figure

Borehole climatology: a discussion based on contributions from climate modeling

Progress in understanding climate variability through the last millennium leans on simulation and reconstruction efforts. Exercises blending both approaches present a great potential for answering questions relevant both for the simulation and reconstruction of past climate, and depend on the specific peculiarities of proxies and methods involved in climate reconstructions, as well as on the realism and limitations of model simulations. This paper explores research specifically related to paleoclimate modeling and borehole climatology as a branch of climate reconstruction that has contributed significantly to our knowledge of the low frequency climate evolution during the last five centuries. The text flows around three main issues that group most of the interaction between model and geothermal efforts: the use of models as a validation tool for borehole climate reconstructions; comparison of geothermal information and model simulations as a means of either model validation or inference about past climate; and implications of the degree of realism on simulating subsurface climate on estimations of future climate change. The use of multi-centennial simulations as a surrogate reality for past climate suggests that within the simplified reality of climate models, methods and assumptions in borehole reconstructions deliver a consistent picture of past climate evolution at long time scales. Comparison of model simulations and borehole profiles indicate that borehole temperatures are responding to past external forcing and that more realism in the development of the soil model components in climate models is desirable. Such an improved degree of realism is important for the simulation of subsurface climate and air-ground interaction; results indicate it could also be crucial for simulating the adequate energy balance within climate change scenario experiments

Pyhtään kunnan kuljetusten optimointi ja tarkistustyökalu

Pyhtään kunta on yli 5 000 asukkaan maalaiskunta Kymenlaaksossa Kaakkois-Suomessa. Kunnan toimeksiantona selvitettiin kuljetusten parantamismahdollisuudet. Pyhtään kunnan kuljetusselvitys koostui neljästä eri kuljetusosa-alueesta: koulukuljetuksesta, vammaispalvelusta, ruokakuljetuksesta ja Pyhtään palvelulinjasta. Selvityksen pääpaino oli koulukuljetuksissa. Tavoitteina oli löytää kuljetuksista kustannussäästöjä, selvittää vuoroliikenteen pysyvyys ja rakentaa tarkistustyökalu. Selvitystyö koostui myös Suomen lainsäädännön tarkastelusta, kuljetusten nykytilan selvittämisestä ja niiden mahdollisesta yhdistämisestä sekä koulukuljetuskustannusten laskemisesta. Työmenetelmät olivat tiedon keruu ja analysointi, yhteydenotot ja haastattelut sekä tarkistustyökalun luominen MS Excel -taulukkolaskentaohjelmalla. Työn tuloksena syntyivät koulukuljetuskartat ja ehdotus koulukuljetusportfolion laatimisesta sekä kaksi tarkistustyökalua. Lisäksi selvitystyössä päädyttiin siihen, että koulukuljetuskustannusten nousu on johtunut epäonnistuneesta kilpailutuksesta.The municipality of Pyhtää has over 5000 inhabitants and is located in Southern Finland. The aim of this thesis was to make a report to the municipality of Pyhtää, Finland. The report consisted of four different fields of transportation: school transport, services for the disabled, transport of perishable foodstuff and service line of Pyhtää. The main subject was the school transportation. The aims of the thesis were to find cost savings, clarify the permanence of bus lines and create a control tool to the municipality’s personnel. The report also consisted of Finnish legislation, monitoring the present state of transport, drawing the route maps from the school transportation and counting the transportation costs. The methods were finding and analyzing the available information, contacting and interviewing involved parties. The control tool was built with MS Office Excel –program. The results of the thesis were the school transport’s route maps, suggestion to create a portfolio from the school transportation and two different versions of the control tool. In addition the thesis concluded that the cost of the school transportation has increased from the unsuccessful tendering

Effects of bottom boundary placement on subsurface heat storage: Implications for climate model simulations

A one-dimensional soil model is used to estimate the influence of the position of the bottom boundary condition on heat storage calculations in land-surface components of General Circulation Models (GCMs). It is shown that shallow boundary conditions reduce the capacity of the global continental subsurface to store heat by as much as 1.0 x 10²³ Joules during a 110-year simulation with a 10 m bottom boundary. The calculations are relevant for GCM projections that employ land-surface components with shallow bottom boundary conditions, typically ranging between 3 to 10 m. These shallow boundary conditions preclude a large amount of heat from being stored in the terrestrial subsurface, possibly allocating heat to other parts of the simulated climate system. The results show that climate models of any complexity should consider the potential for subsurface heat storage whenever choosing a bottom boundary condition in simulations of future climate change

Adaptive anti-predatory responses of European rabbits exposed to different predation pressure

Prey species develop anti-predatory strategies as a response to minimising the risk of being predated. However, how the European rabbit (Oryctolagus cuniculus) adapts to different predator pressure is not fully known. Here, we studied the adaptive anti-predatory responses of European rabbits exposed to different terrestrial predation pressure. To do this, we took advantage of a rabbit translocation programme in the Sierra Norte Natural Park of Sevilla (SW Spain), where rabbits from the same donor population were translocated in plots with and without terrestrial predator exclusion fences (aerial predation was not excluded in any of the plots). This presented an ideal opportunity to observe whether the behaviour of individuals from the same population adapts to situations with different predator pressure; thus, their behaviour was evaluated through direct observations. Although most rabbits were observed close to cover, differences in distance to cover, group size and behaviour were observed between fenced and unfenced plots. Overall, both adult and juvenile rabbits moved further from cover in the unfenced plot than in the fenced plot. Most of the observations in the unfenced plot corresponded to rabbits in pairs or alone; whereas in the fenced plot, rabbits were primarily in pairs or in larger groups. Our findings suggest that in the unfenced plot, rabbits that moved further from cover were often part of larger groups (≥ 4 rabbits); whereas in the fenced plot, it was rabbits in smaller groups (< 4 rabbits). Rabbits in the unfenced plot were alert and running more frequently than rabbits in the fenced one; in the latter, these rabbits were mostly feeding. Other relaxed behaviours such us grooming or resting were more frequent close to cover. In summary, our results highlight rabbits' capacity to promptly adjust behaviour in response to predation risk, exhibiting adaptive anti-predatory responses tailored to different predation pressures. These insights contribute to understanding the nuanced dynamics of prey species' responses to diverse predation scenarios

Multi-expert analysis and validation of objective vascular tortuosity measurements

The conference was held in Belgrade, Serbia, 3-5 September 2018.[Absctract]: The retinal vascular tortuosity is a commonly used parameter for the early diagnosis of several diseases that affects the circulatory system. The manual analysis of fundus images for the tortuosity characterization is a time-consuming and subjective task that presents a high inter-rater variability. Thus, automatic image processing methods allow the efficient computation of objective and stable parameters for the issue. The validation of these methods is crucial to ensure an objective and reliable environment for the retinal experts. This paper describes a multi-expert analysis that measures the clinical performance as well as a validation procedure of the computational tortuosity module of the Sirius framework, a computer-aided diagnosis platform for analyzing retinal images.This research has been economically supported by the Instituto de Salud Carlos III, Government of Spain and FEDER funds of the European Union through the PI14/02161 and the DTS15/00153 research projects and by the Ministerio de Econom´ıa y Competitividad, Government of Spain through the DPI2015-69948-R research project. Also, this work has received financial support from the European Union (European Regional Development Fund - ERDF) and the Xunta de Galicia, Centro singular de investigaci´on de Galicia accreditation 2016-2019, Ref. ED431G/01; and Grupos de Referencia Competitiva, Ref. ED431C 2016-047.Xunta de Galicia; ED431G/01Xunta de Galicia; ED431C 2016-04

Consistent accretion-induced heating of the neutron-star crust in MXB 1659-29 during two different outbursts

Monitoring the cooling of neutron-star crusts heated during accretion outbursts allows us to infer the physics of the dense matter present in the crust. We examine the crust cooling evolution of the low-mass X-ray binary MXB 1659-29 up to ~505 days after the end of its 2015 outburst (hereafter outburst II) and compare it with what we observed after its previous 1999 outburst (hereafter outburst I) using data obtained from the Swift, XMM-Newton, and Chandra observatories. The observed effective surface temperature of the neutron star in MXB 1659-29 dropped from ~92 eV to ~56 eV from ~12 days to ~505 days after the end of outburst II. The most recently performed observation after outburst II suggests that the crust is close to returning to thermal equilibrium with the core. We model the crust heating and cooling for both its outbursts collectively to understand the effect of parameters that may change for every outburst (e.g., the average accretion rate, the length of outburst, the envelope composition of the neutron star at the end of the outburst) and those which can be assumed to remain the same during these two outbursts (e.g., the neutron star mass, its radius). Our modelling indicates that all parameters were consistent between the two outbursts with no need for any significant changes. In particular, the strength and the depth of the shallow heating mechanism at work (in the crust) were inferred to be the same during both outbursts, contrary to what has been found when modelling the cooling curves after multiple outburst of another source, MAXI J0556-332. This difference in source behaviour is not understood. We discuss our results in the context of our current understanding of cooling of accretion-heated neutron-star crusts, and in particular with respect to the unexplained shallow heating mechanism.Comment: Submitted to A&A. The supplementary video can be found at https://www.youtube.com/watch?v=OpJ053zq9-

Warming will affect phytoplankton differently: evidence through a mechanistic approach

Although the consequences of global warming in aquatic ecosystems are only beginning to be revealed, a key to forecasting the impact on aquatic communities is an understanding of individual species' vulnerability to increased temperature. Despite their microscopic size, phytoplankton support about half of the global primary production, drive essential biogeochemical cycles and represent the basis of the aquatic food web. At present, it is known that phytoplankton are important targets and, consequently, harbingers of climate change in aquatic systems. Therefore, investigating the capacity of phytoplankton to adapt to the predicted warming has become a relevant issue. However, considering the polyphyletic complexity of the phytoplankton community, different responses to increased temperature are expected. We experimentally tested the effects of warming on 12 species of phytoplankton isolated from a variety of environments by using a mechanistic approach able to assess evolutionary adaptation (the so-called ratchet technique). We found different degrees of tolerance to temperature rises and an interspecific capacity for genetic adaptation. The thermal resistance level reached by each species is discussed in relation to their respective original habitats. Our study additionally provides evidence on the most resistant phytoplankton groups in a future warming scenario

Computational assessment of the retinal vascular tortuosity integrating domain-related information

[Abstract] The retinal vascular tortuosity presents a valuable potential as a clinical biomarker of many relevant vascular and systemic diseases. Commonly, the existent approaches face the tortuosity quantification by means of fully mathematical representations of the vessel segments. However, the specialists, based on their diagnostic experience, commonly analyze additional domain-related information that is not represented in these mathematical metrics of reference. In this work, we propose a novel computational tortuosity metric that outperforms the mathematical metrics of reference also incorporating anatomical properties of the fundus image such as the distinction between arteries and veins, the distance to the optic disc, the distance to the fovea, and the vessel caliber. The evaluation of its prognostic performance shows that the integration of the anatomical factors provides an accurate tortuosity assessment that is more adjusted to the specialists’ perception.Instituto de Salud Carlos II; DTS18/00136Ministerio de Ciencia, Innovación y Universidades; DPI2015-69948-RMinisterio de Ciencia, Innovación y Universidades; RTI2018-095894-B-I00Xunta de Galicia; ED431G/01Xunta de Galicia; ED431C 2016-04