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Abstract Janzen’s hypothesis (1967; American Naturalist) predicts that tropical habitats with reduced thermal seasonality would select for species with narrow thermal tolerance, thereby limiting dispersal among sites of different elevations showing little overlap in temperature. These predictions have so far been tested by confronting tropical and temperate mountain communities, leaving unresolved the question of their generalization to habitats with low thermal seasonality outside the tropics. We provide the first extension of Janzen’s hypothesis to temperate habitats, by testing for differences in thermal tolerance and elevational range among congeneric alpine spiders (Araneae: Linyphiidae: Troglohyphantes) occurring along a steep gradient of decreasing thermal seasonality with increasing cave depth. Using species from the same temperate region rather than from distinct biogeographic regions avoids confounding the effects of short‐ and long‐term climatic variability on thermal tolerance and elevational range extent. Following Jansen’s assumptions, we predicted that cave habitats with low thermal seasonality would select for narrow thermal tolerance. Also, specialized subterranean species would exhibit both narrower elevational range extents and smaller realized thermal niche breadths. Initially, we showed that thermal seasonality and the overlap in temperature across caves were considerably lower in deep than in shallow cave habitats. Then, we measured thermal tolerance and used morphological traits to quantify the degree of specialization to subterranean life of 11 spider species. We found that thermal tolerance decreased with increasing subterranean specialization. Deep subterranean species reached their critical temperature at 1–4°C above their habitat temperature, whereas shallow subterranean species withstood a twofold larger temperature increase. At last, we demonstrated that a species’ elevational range extent and the variation of temperature encountered across its range decreased with increasing specialization to deep subterranean life. Our integrative work, being grounded in organismal and habitat measures, represents the first generalization of Janzen’s framework to caves and provides a conceptual framework to disentangle the effect of long‐term climate variability on subterranean biodiversity patterns. Extending Janzen’s thoughts to a broader range of ecosystems is key to understanding how the ecological specialization–dispersal trade‐off may constrain the response of species to climate change. A free Plain Language Summary can be found within the Supporting Information of this article.

The EU DEMO Plant Electrical System (PES) main scopes are to supply all the plant electrical loads and to deliver to the Power Transmission Grid (PTG) the net electrical power generated. The studies on the PES during the Pre- Concept Design (PCD) Phase were mainly addressed to understand the possible issues, related to the special features both of the power generated, with respect to a power plant of the same size, and of the power to be supplied to the electrical loads. For this purpose, the approach was to start the design of the different PES components adopting technologies already utilized in fusion experiments and in Nuclear Power Plants (NPP) to verify their applicability and identify possible limits when scaled to the DEMO size and applied to the specific pulsed operating conditions. This work is not completed, however several issues have been already identified related to the pulsed operation of the turbine generator, the large amount of recirculation power, the very high peaks of active power required for the plasma formation and control, the huge reactive power demand, if thyristor converter technology was adopted to supply the superconducting coils, etc.. The paper gives an overview on the features and scope of the PES and its subsystems, on the main achievements during the Pre- Concept Design (PCD) Phase, on the challenges for the development of the conceptual design in the next framework program and on the plan to face them.

Infrared to visible upconversion (UC) is a promising way to enhance the efficiency of silicon based solar cells. In this paper, the spectral conversion and recovery of sub-band gap photons of the solar spectrum, from NIR-IR to the VIS-NIR wavelength region, is investigated in two fluorides hosts doped with trivalent erbium ions (Er3+). The efficiency gain due to upconversion in silicon solar cells is compared for single crystal samples of BaY2F8:Er3+ and LiYF4:Er3+ in a dedicated upconverter solar cell device (UCSCD) with monochromatic excitation in the 1.5 mu m spectral region. The highest external quantum efficiency due to upconversion was found for the UCSCD using the BaY2F8:30 at% Er3+ single crystal, reaching an EQE of 6.8 +/- 0.2% for (1.10 +/- 0.12).10(5) W m(-2) spectral irradiance at 1494 nm. We present a comprehensive spectroscopic study of the crystal samples also taking into account the effects of the different crystal symmetry as well as the different phonon energies. Our findings enable us to explain the higher efficiency of the BaY2F8:Er3+ compared to the LiYF4:Er3+ upconverter in terms of both static and dynamic properties. (C) 2016 Elsevier B.V. All rights reserved.

We report on flexible photovoltaic cell fabricated on polymeric substrate optimized for indoor energy harvesting. We have fabricated small area modules (up to 30 cm(2)) obtained by monolithic integration of a-Si:H p-i-n solar cells deposited by PECVD at low temperature with excellent mechanical strength, high ability of folding and very good stability. The photovoltaic thin film module is optimized for indoor light generated by indoor lamps and has efficiency as high as 9.1% on aperture area even at less than 100 lx of light intensity (under F12 fluorescent lamp spectrum). The optimized system can be used to energize thin film batteries and can be assembled in a flexible system associated with a wireless sensor network or other electronic devices. (C) 2014 Elsevier B.V. All rights reserved.

Abstract. Phytoplankton calcifiers contribute to global carbon cycling through their dual formation of calcium carbonate and particulate organic carbon (POC). The carbonate might provide an efficient export pathway for the associated POC to the deep ocean, reducing the particles' exposure to biological degradation in the upper ocean and increasing the particle settling rate. Previous work has suggested ballasting of POC by carbonate might increase in a warming climate, in spite of increasing carbonate dissolution rates, because calcifiers benefit from the widespread nutrient limitation arising from stratification. We compare the biogeochemical responses of three models containing (1) a single mixed phytoplankton class, (2) additional explicit small phytoplankton and calcifiers, and (3) additional explicit small phytoplankton and calcifiers with a prognostic carbonate ballast model, to two rapid changes in atmospheric CO2. The first CO2 scenario represents a rapid (151-year) transition from a stable icehouse climate (283.9 ppm) into a greenhouse climate (1263 ppm); the second represents a symmetric rapid transition from a stable greenhouse climate into an icehouse climate. We identify a slope change in the global net primary production response with a transition point at about 3.5 ∘C global mean sea surface temperature change in all models, driven by a combination of physical and biological changes. We also find that in both warming and cooling scenarios, the application of a prognostic carbonate ballast model moderates changes in carbon export production, suboxic volume, and nitrate sources and sinks, reducing the long-term model response to about one-third that of the calcifier model without ballast. Explicit small phytoplankton and calcifiers, and carbonate ballasting, increase the physical separation of nitrate sources and sinks through a combination of phytoplankton competition and lengthened remineralization profile, resulting in a significantly higher global nitrate inventory in this model compared to the single phytoplankton type model (15 % and 32 % higher for icehouse and greenhouse climates). Higher nitrate inventory alleviates nitrate limitation, increasing phytoplankton sensitivity to changes in physical limitation factors (light and temperature). This larger sensitivity to physical forcing produces stronger shifts in ocean phosphate storage between icehouse and greenhouse climates. The greenhouse climate is found to hold phosphate and nitrate deeper in the ocean, despite a shorter remineralization length scale than the icehouse climate, because of the longer residence times of the deep water masses. We conclude the global biogeochemical impact of calcifiers extends beyond their role in global carbon cycling, and that the ecological composition of the global ocean can affect how ocean biogeochemistry responds to climate forcing.

AMADEUS es un proyecto europeo que investiga materiales y dispositivos de estado sólido para almacenar energía a muy alta temperatura. Usando aleados de silicio como materiales de cambio de fase se alcanzan calores latentes superiores a 1000 kWh/m3, propiciando la obtención de altísimas densidades energéticas. Dichos aleados suponen temperaturas de almacenamiento por encima de los 1000 ºC, muy por encima de las de los sistemas actuales de acumulación térmica. El artículo describe las actividades del proyecto y sus primeros resultados, explicando los principales retos de este nuevo sistema que combina la acumulación de energía en forma de calor en silicio fundido con dispositivos de estado sólido termiónicos y termofotovoltaicos para la posterior conversión en electricidad. AMADEUS is a H2020 project that researches on materials and solid-state devices for very high temperature energy storage and conversion. By exploring silicon-based alloys as new phase change materials (PCMs), latent heat higher than 1000 kWh/m3 is achievable, which implies a very high energy density. In addition, silicon-based PCMs lead to storage temperatures well beyond 1000 ºC, well beyond that of current state-of-the-art thermal energy storage (TES). This paper describes the project R&D activities and first results, and comments on challenges towards a new kind of systems combining latent heat energy storage in molten silicon with thermionic and thermophotovoltaic solid state heat-to-power conversion.

Over the past 20 years, the focus of forest science on air pollution has moved from forest decline to a holistic framework of forest health, and from the effects on forest production to the ecosystem services provided by forest ecosystems. Hence, future research should focus on the interacting factorial impacts and resulting antagonistic and synergistic responses of forest trees and ecosystems. The synergistic effects of air pollution and climatic changes, in particular elevated ozone, altered nitrogen, carbon and water availability, must be key issues for research. Present evidence suggests air pollution will become increasingly harmful to forests under climate change, which requires integration amongst various stressors (abiotic and biotic factors, including competition, parasites and fire), effects on forest services (production, biodiversity protection, soil protection, sustained water balance, socio-economical relevance) and assessment approaches (research, monitoring, modeling) to be fostered.