Spatio-temporal variability of micro-, nano- and pico-phytoplankton in the Mediterranean Sea from satellite ocean colour data of SeaWiFS

Abstract. The seasonal and year-to-year variability of the phytoplankton size class (PSC) spatial distribution has been examined in the Mediterranean Sea by using the entire time series of Sea-viewing Wide Field-of-view Sensor (SeaWiFS) space observations (1998–2010). Daily maps of PSCs have been determined using an empirical model based on a synoptic relationship between surface chlorophyll a and diagnostic pigments referred to different taxonomic groups. The analysis of micro-, nano- and pico-phytoplankton satellite time series (1998–2010) describes, quantitatively, the algal assemblage structure over the basin and reveals that the main contribution to chlorophyll a in most of the Mediterranean Sea comes from the pico-phytoplankton component, especially in nutrient-poor environments. Regions with different and peculiar features are the Northwestern Mediterranean Sea, the Alborán Sea and several coastal areas, such as the North Adriatic Sea. In these areas, local interactions between physical and biological components modulate the composition of the three phytoplankton size classes. It results that, during the spring bloom season, micro-phytoplankton dominates in areas of intense vertical winter mixing and deep/intermediate water formation, while in coastal areas micro-phytoplankton dominates in all seasons because of the nutrient supply from the terrestrial inputs. In the Alborán Sea, where the Atlantic inflow modulates the nutrient availability, any predominance of one class over the other two has been observed. The nano-phytoplankton component instead remains widespread over the entire basin along the year, and its contribution to chlorophyll a is of the order of 30–40 %. The largest inter-annual signal occurs in the Northwestern Mediterranean Sea, driven by the year-to-year variation in intensity and extension of the spring bloom, followed by the Alborán Sea, in which the inter-annual variability is strongly modulated by the Atlantic inflow. In absence of sufficient in situ data of community composition, the satellite-based analysis demonstrated that pico-, nano- and micro-phytoplankton classes often coexist. The predominance of one group over the other ones is strongly dependent on the physical and biological processes occurring at the mesoscale. These processes directly influence the nutrient and light availability, which are the principal forcing for the algae growth

Modelling of a falling-film evaporator for adsorption chillers.

The objective of the present study was to develop a dynamic model to simulate a prototype falling-film evap-orator that is part of a single-bed adsorption chiller test bench located at the Department of Energy of the Politecnico di Milano. The model is based on the evaporator energy and mass balances and was calibrated and validated using experimental data coming from realistic operating conditions in a range of inlet chilled water temperatures (Tin,chw) from 15 to 25 °C. From the experimental data, it was obtained that the average overall heat transfer conductance (UA) was approximately 530 W/K for all temperatures during the quasi steady-state section of the process. A correlation to calculate the wetted surface through a variable called wettability factor (fwet) was developed from experimental data. The fwet factors were identified using the model and were in the range of 0.80 - 0.20 (Tin,chw= 15 °C) and 0.60 - 0.20 (Tin,chw= 25 °C). It was seen that, the higher the Tin,chw, the lower the fwet values. The UA and saturation temperature (Tref,sat) values from the model were in good accordance with experimental data during the quasi steady-state section of the process. Nevertheless, the final transition stage (i. e., a situation in which the evaporator's refrigerant pool is empty) required an additional hypothesis due to the uncertain process' dynamics. The mass and energy balances that are part of the hydrodynamics and heat transfer sections of the model use Nusselt's classic theory for falling-film

Controversies in the treatment of mild asthma. What novelties and practical implications?

Mild asthma is prevalent in childhood and causes as many as 30%–40% asthma exacerbations requiring emergency visits. The management of "intermittent" and "mild persistent" asthma phenotypes is still a matter of debate, even if the role of inhaled corticosteroids, both continuous and intermittent, is a cornerstone in this field. Recent updates of the guidelines on the strategies to manage these patients are coming, since the role of inflammation in these asthma phenotypes is crucial, as well as the potential side effect and risks of short-acting beta 2 agonists overuse, prescribed as the only "as-needed" treatments. In this paper, we overview the new (r)evolution regarding intermittent and mild persistent asthma management

X-ray-absorption fine-structure study of ZnSexTe1−x alloys

X-ray-absorption fine-structure experiments at different temperatures in ZnSexTe1−x (x=0, 0.1, 0.2, 0.55, 0.81, 0.93, 0.99, and 1.0) have been performed in order to obtain information about the structural relaxation and disorder effects occurring in the alloys. First and second neighbor distance distributions have been characterized at the Se and Zn K edges, using multiple-edge and multiple-scattering data analysis. The first neighbor distance distribution was found to be bimodal. The static disorder associated with the Zn–Te distance variance did not depend appreciably on composition. On the other hand, the static disorder associated with the Zn–Se distance increased as the Se content diminished. Using the bonding angle information provided by our experiments the point of view of the anion has been related to that of the cation. The resulting structural model indicates that Zn tetrahedra surrounding the anions remain essentially undistorted, but forced to tilt from their ideal zincblende orientation to accommodate the minority element. The main origin of structural disorder is [email protected] ; [email protected]

Depth profiling of melting and metallization in Si(111) and Si(001) surfaces

International audienc

Testing of an adsorption chiller prototype for data center cooling.

The main objective of this study is to present a novel adsorption chiller prototype (designed and realized by the company Sorption Technologies GmbH) that is suitable for cooling of data center servers. This prototype has been designed to fit into commercially-available data center racks. This adsorption prototype has been designed to cool down the rack servers by means of liquid cooling. Furthermore, an air-cooler heat exchanger is also integrated into the adsorption machine to cool down the rest of the rack components (i.e., patch panels, HDD). This way, the adsorption system is able to cool down all rack components. Phase-change chambers are integrated into the adsorption modules for direct evaporation/condensation, removing the need of large vacuum valves and allowing to have a more simpler and compact vacuum system. This also means that the refrigerant distribution is completely done in liquid phase. The prototype is installed at the Department of Energy at the Politecnico di Milano and testing will be carried out using cooling water temperatures in the range 25 – 30 °C and hot water temperatures in the range 55 – 65 °C

Poster: Continual Network Learning

We make a case for in-network Continual Learning as a solution for seamless adaptation to evolving network conditions without forgetting past experiences. We propose implementing Active Learning-based selective data filtering in the data plane, allowing for data-efficient continual updates. We explore relevant challenges and propose future research directions

Selective inhibition of genomic and non-genomic effects of thyroid hormone regulates muscle cell differentiation and metabolic behavior

Thyroid hormones (THs) are key regulators of different biological processes. Their action involves genomic and non-genomic mechanisms, which together mediate the final effects of TH in target tissues. However, the proportion of the two processes and their contribution to the TH-mediated effects are still poorly understood. Skeletal muscle is a classical target tissue for TH, which regulates muscle strength and contraction, as well as energetic metabolism of myofibers. Here we address the different contribution of genomic and non-genomic action of TH in skeletal muscle cells by specifically silencing the deiodinase Dio2 or the β3-Integrin expression via CRISPR/Cas9 technology. We found that myoblast proliferation is inversely regulated by integrin signal and the D2-dependent TH activation. Similarly, inhibition of the nuclear receptor action reduced myoblast proliferation, confirming that genomic action of TH attenuates proliferative rates. Contrarily, genomic and non-genomic signals promote muscle differentiation and the regulation of the redox state. Taken together, our data reveal that integration of genomic and non-genomic signal pathways finely regulates skeletal muscle physiology. These findings not only contribute to the understanding of the mechanisms involved in TH modulation of muscle physiology but also add insight into the interplay between different mechanisms of action of TH in muscle cells