Experimental study of the surface marine atmospheric boundary layer over Aegean Greece

Micrometeorological measurements within the surface Marine Atmospheric Boundary Layer (MABL) took place at the shoreline of island of Karpathos, at the South East end of the Aegean Sea (Karpathio Pelagos), during summer 2012. Α meteorological mast was installed at a distance less than 30m from the shoreline, instrumented with a sonic anemometer and a fast krypton hygrometer at 14.5m height with a sampling frequency of 10Hz, in order to measure the turbulent transport of mass and energy of the surface MABL. At the same mast slow response sensors (1Hz) were also installed providing vertical profiles of wind speed and direction, temperature and humidity at three levels (3, 8 and 12 m). Satellite sea surface temperature images were also obtained. The spacial and temporal scales of the Aegean Pelagos have not been studied in the past while it is expected to present differences compared with those measured over oceans or open seas. It is worth to mention that this study is a follow-up of a previous study which took place during summer 2011 at Skyros island, northern Aegean provided similar measurements but with different fetch. During Karpathos campaign, more than of 120 hours stationary surface MABL observations of near neutral wind flows were recorded. The vertical profiles of temperature reveal the presence of a coastal internal boundary layer, mostly below 8m height. Eddy correlation analysis is used to study the turbulent fluxes of mass and energy. According to first results on the stable MABL, momentum fluxes depend on stability and give increasing values with the wind speed. The estimated values are higher, almost by a factor of two, compared to typical values measured over the ocean. These increased values could be attributed to a developed sea state since wind stress is greater over young and developing wave fields. Sensible heat flux is found to be increased with stability and rather independent from wind speed while moisture flux seems to not be dependent neither to stability or wind speed. Some part of the records present upward heat fluxes under near neutral conditions and mostly for positive sea-air temperature differences, possibly associated with sea spray or mesoscale heterogeneity of the sea surface temperature. Ongoing investigation of the turbulent exchanges is expected to provide a more thorough insight on the coupling processes between the surface MABL and Aegean sea

Flux measurements in the surface marine Atmospheric Boundary Layer over the Aegean Sea, Greece

Micro-meteorological measurements within the surface Marine Atmospheric Boundary Layer took place at the shoreline of two islands at northern and south-eastern Aegean Sea of Greece. The primary goal of these experimental campaigns was to study the momentum, heat and humidity fluxes over this part of the north-eastern Mediterranean Sea, characterized by limited spatial and temporal scales which could affect these exchanges at the air–sea interface. The great majority of the obtained records from both sites gave higher values up to factor of two, compared with the estimations from the most widely used parametric formulas that came mostly from measurements over open seas and oceans. Friction velocity values from both campaigns varied within the same range and presented strong correlation with the wind speed at 10 m height while the calculated drag coefficient values at the same height for both sites were found to be constant in relation with the wind speed. Using eddy correlation analysis, the heat flux values were calculated (virtual heat fluxes varied from −60 to 40 W/m2) and it was found that they are affected by the limited spatial and temporal scales of the responding air–sea interactionmechanism. Similarly, the humidity fluxes appeared to be strongly influenced by the observed intense spatial heterogeneity of the sea surface temperature

Experimental study of the turbulent structure of the surface marine Atmospheric Boundary Layer over the Aegean Pelagos under etesian winds

In order to study the physical processes of the turbulent transportation of mass and energy within the surface Marine Atmospheric Boundary Layer over the Aegean Pelagos, field measurements were conducted on the island of Skyros, mainly under the etesian winds, during summer 2011. Α meteorological mast was installed close to the shoreline, instrumented with fast anemometer (sonic) and hydrometer measuring the three components of the wind, the virtual temperature and water vapor at 10m height with a sampling frequency of 20Hz. At the same mast slow response sensors were measuring wind speed and direction, temperature and humidity at three levels (2, 6 and 10 m). Weak stable to near neutral flows were recorded during the experimental period. The eddy correlation analysis re-vealed the momentum and heat fluxes values which are presented and discussed. The estimated values are related both with stability and wind speed variations

Arachnoid cysts: the role of the BLADE technique

Background: This study aims at demonstrating the ability of BLADE sequences to reduce or even eliminate all the image artifacts as well as verifying the significance of using this technique in certain pathological conditions

The innate sensor ZBP1-IRF3 axis regulates cell proliferation in multiple myeloma

Multiple myeloma is a malignancy of plasma cells (PC) initiated and driven by primary and secondary genetic events. Nevertheless, myeloma PC survival and proliferation might be sustained by non-genetic drivers. Z-DNA-binding protein 1 (ZBP1; also known as DAI) is an interferon-inducible, Z-nucleic acid sensor that triggers RIPK3-MLKL-mediated necroptosis in mice. ZBP1 also interacts with TBK1 and the transcription factor IRF3 but the function of this interaction is unclear, and the role of ZBP1-IRF3 axis in cancer is not known. Here we show that ZBP1 is selectively expressed in late B cell development in both human and mouse cells and it is required for optimal T-cell-dependent humoral immune responses. In myeloma PC, interaction of constitutively expressed ZBP1 with TBK1 and IRF3 results in IRF3 phosphorylation. IRF3 directly binds and activates cell cycle genes, in part through co-operation with the PC lineage-defining transcription factor IRF4, and thereby promoting myeloma cell proliferation. This generates a novel, potentially therapeutically targetable and relatively selective myeloma cell addiction to the ZBP1-IRF3 axis. Our data also show a non-canonical function of constitutive ZBP1 in human cells and expand our knowledge of the role of cellular immune sensors in cancer biology

Do Empowered Front-Line Employees Perform Better? A Non-linear Approach and the Role of Service Complexity

This study re-examines the influence of front-line service employee empowerment on their performance, following a non-linear approach and integrating the role of service complexity. For that purpose, data were collected through a quantitative survey on 240 front-line employees in two major UK cities (London, Leeds). The study’s results indicate that empowerment has a significant impact on their performance and that this impact is non-linear (quadratic). Specifically, the relationship between empowerment and performance is negative for low-level empowerment and positive for high-level empowerment. In addition, the study’s results show that the nature of this relationship is different for different levels of service complexity. Specifically, for low-complexity services, the relationship between empowerment and performance was found quadratic, whereas for high-complexity services the relationship was found positive and linear. Based on the study’s main conclusions important implications for both academics and practitioners are presented

MAF functions as a pioneer transcription factor that initiates and sustains myelomagenesis

Deregulated expression of lineage-affiliated transcription factors (TFs) is a major mechanism of oncogenesis. However, how the deregulation of nonlineage affiliated TF affects chromatin to initiate oncogenic transcriptional programs is not well-known. To address this, we studied the chromatin effects imposed by oncogenic MAF as the cancer-initiating driver in the plasma cell cancer multiple myeloma. We found that the ectopically expressed MAF endows myeloma plasma cells with migratory and proliferative transcriptional potential. This potential is regulated by the activation of enhancers and superenhancers, previously inactive in healthy B cells and plasma cells, and the cooperation of MAF with the plasma cell-defining TF IRF4. Forced ectopic MAF expression confirms the de novo ability of oncogenic MAF to convert transcriptionally inert chromatin to active chromatin with the features of superenhancers, leading to the activation of the MAF-specific oncogenic transcriptome and the acquisition of cancer-related cellular phenotypes such as CCR1-dependent cell migration. These findings establish oncogenic MAF as a pioneer transcription factor that can initiate as well as sustain oncogenic transcriptomes and cancer phenotypes. However, despite its pioneer function, myeloma cells remain MAF-dependent, thus validating oncogenic MAF as a therapeutic target that would be able to circumvent the challenges of subsequent genetic diversification driving disease relapse and drug resistance

Low- and high-fidelity modeling of sandwich-structured composite response to bird strike, as tools for a digital-twin-assisted damage diagnosis

EU, H2020 Smart, Green and Integrated Transport, Aviation program under the acronym EXTREME (Project reference 636549)

On the fatigue life prediction of CFRP laminates using the Electrical Resistance Change method

International audienceThe electromechanical response (Electrical Resistance Change method) as a damage index of quasi-isotropic Carbon Fiber Reinforced (CFRPs) laminates under fatigue loading was investigated. The effect of dispersed Multi-Wall Carbon Nanotubes (MWCNT) into the epoxy matrix was additionally evaluated and compared with neat epoxy CFRPs. The longitudinal resistance change of the specimens was monitored throughout the fatigue experiment. Three different stress levels were tested. The frequency and the ratio (R) of the minimum applied load (stress) to the maximum applied load (stress) were kept constant for the different stress levels. The temperature of the specimen was also monitored throughout the process in order to deduce its effect on the electrical resistance of the specimen. The electrical behavior of the quasi-isotropic CFRP deviated from the commonly observed electrical response of unidirectional or cross-ply CFRPs due to the presence of the 45 layers. During initial stages of loading the resistance drops and afterwards it follows a positive slope up to final fracture. This repeatable pattern was observed for both the neat and the CNT-doped specimens, with the latter having smoother electrical recordings. The effect of temperature was calculated to be limited for the specific material and test/measurement configuration. The electromechanical response was correlated to stiffness degradation and acoustic emission findings enabling the identification of the specific regions during the fatigue life referring to specific mechanisms of damage accumulation. More specifically the experimental results revealed that the occurrence of the initial drop of the electrical resistance is linked with the occurrence of the Characteristic Damage State (CDS), associated with a specific percentage of stiffness reduction. This finding was used in order to predict the remaining life independently from the applied stress level with a high degree of confidence, assuming a constant stress level throughout the whole lifetime. The remaining life prediction for the CNT-doped specimens had higher coefficient of confidence (R)