Observational studies of gas in protoplanetary disks

The gas dominates the mass and dynamics of protoplanetary disks.However, very few observational constraints exist about the physical properties of the gas in the planet forming region of the disks. This thesis presents an ensemble of new observational projects aimed at studying the gas in the disks of selected nearby Herbig Ae/Be stars (HAEBES) and classical T Tauri stars (CTTS). In the first chapter we present a search for CO 4.7 micron ro-vibrational emission from HAEBES using ISAAC, ESO's first generation VLT near-infrared spectrograph. In the second chapter, we describe a project in which we intended to probe the outer cold gas of protoplanetary disks, by measuring gas absorption features of the disk superimposed on the optical spectra of close (< 1.5") visual companions of nearby HAEBES utilizing FORS2, ESO's VLT optical spectrograph. In the third chapter, we present a large observational effort to detect H2 fundamental rotational emission at 12.278 and 17.035 $\mu$m from HAEBES employing VISIR, ESO's new high-resolution mid-infrared spectrograph. In the fourth chapter, we describe the first results of a sensitive search for near-infrared H2 ro-vibrational emission at 2.1218, 2.2233 and 2.2477 micron in the CTTS LkHa 264 and the debris disk 49 Cet using CRIRES, ESO's new VLT near-infrared high-resolution spectrograph. From our observations (detections and non-detections), we derive important constraints on the physical properties of the studied disks (e.g. mass, column density, temperature, age, excitation mechanism, inclination). We show that high-resolution infrared spectroscopy is a crucial tool for future studies of the structure of protoplanetary disks

Effect of hydrogen bonding and complexation with metal ions on the fluorescence of luotonin A

Fluorescence characteristics of a biologically active natural alkaloid, luotonin A (LuA), were studied by steady-state and time-resolved spectroscopic methods. The rate constant of the radiationless deactivation from the singlet-excited state diminished by more than one order of magnitude when the solvent polarity was changed from toluene to water. Dual emission was found in polyfluorinated alcohols of large hydrogen bond donating ability due to photoinitiated proton displacement along the hydrogen bond. In CH 2Cl2, LuA produced both 1:1 and 1:2 hydrogen-bonded complexes with hexafluoro-2-propanol (HFIP) in the ground state. Photoexcitation of the 1:2 complex led to protonated LuA, whose fluorescence appeared at a long wavelength. LuA served as a bidentate ligand forming 1:1 complexes with metal ions in acetonitrile. The stability of the complexes diminished in the series of Cd2+ > Zn2+ > Ag+, and upon competitive binding of water to the metal cations. The effect of chelate formation on the fluorescent properties was revealed. © 2013 The Royal Society of Chemistry and Owner Societies

Inner disk clearing around the Herbig Ae star HD\,139614: Evidence for a planet-induced gap ?

Spatially resolving the inner dust cavity of the transitional disks is a key to understanding the connection between planetary formation and disk dispersal. The disk around the Herbig star HD 139614 is of particular interest since it presents a pretransitional nature with an au-sized gap, in the dust, that was spatially resolved by mid-IR interferometry. Using new NIR interferometric observations, we aim to characterize the 0.1-10~au region of the HD~139614 disk further and identify viable mechanisms for the inner disk clearing. We report the first multiwavelength radiative transfer modeling of the interferometric data acquired on HD~139614 with PIONIER, AMBER, and MIDI, complemented by Herschel/PACS photometries. We confirm a gap structure in the um-sized dust, extending from about 2.5 au to 6 au, and constrained the properties of the inner dust component: e.g., a radially increasing surface density profile, and a depletion of 10^3 relative to the outer disk. Since self-shadowing and photoevaporation appears unlikely to be responsible for the au-sized gap of HD~139614, we thus tested if dynamical clearing could be a viable mechanism using hydrodynamical simulations to predict the gaseous disk structure. Indeed, a narrow au-sized gap is expected when a single giant planet interacts with the disk. Assuming that small dust grains are well coupled to the gas, we found that a ~ 3~Mjup planet located at 4.5 au from the star could, in less than 1 Myr, reproduce most of the aspects of the dust surface density profile, while no significant depletion in gas occurred in the inner disk, in contrast to the dust. However, the dust-depleted inner disk could be explained by the expected dust filtration by the gap and the efficient dust growth/fragmentation in the inner disk regions. Our results support the hypothesis of a giant planet opening a gap and shaping the inner region of the HD~139614 disk.Comment: Version accepted in A&A, with typos corrections in the tex

A Low Dose of Pure Cannabidiol Is Sufficient to Stimulate the Cytotoxic Function of CIK Cells without Exerting the Downstream Mediators in Pancreatic Cancer Cells

Despite numerous studies conducted over the past decade, the exact role of the cannabinoid system in cancer development remains unclear. Though research has focused on two cannabinoid receptors (CB1, CB2) activated by most cannabinoids, CB2 holds greater attention due to its expression in cells of the immune system. In particular, cytokine-induced killer cells (CIKs), which are pivotal cytotoxic immunological effector cells, express a high-level of CB2 receptors. Herein, we sought to investigate whether inducing CIK cells with cannabidiol can enhance their cytotoxicity and if there are any possible counter effects in its downstream cascade of phosphorylated p38 and CREB using a pancreatic ductal adenocarcinoma cell line (PANC-1). Our results showed that IL-2 modulates primarily the expression of the CB2 receptor on CIK cells used during ex vivo CIK expansion. The autophagosomal-associated scaffold protein p62 was found to co-localize with CB2 receptors in CIK cells and the PANC-1 cell line. CIK cells showed a low level of intracellular phospho-p38 and, when stimulated with cannabidiol (CBD), a donor specific variability in phospho-CREB. CBD significantly decreases the viability of PANC-1 cells presumably by increasing the cytotoxicity of CIK cells. Taken together, in our preclinical in vitro study, we propose that a low effective dose of CBD is sufficient to stimulate the cytotoxic function of CIK without exerting any associated mediator. Thus, the combinatorial approach of non-psychogenic CBD and CIK cells appears to be safe and can be considered for a clinical perspective in pancreatic cancer

FEPDS: A Proposal for the Extraction of Fuzzy Emerging Patterns in Data Streams

Nowadays, most data is generated by devices that produce data continuously. These kinds of data can be categorised as data streams and valuable insights can be extracted from them. In particular, the insights extracted by emerging patterns are interesting in a data stream context as easy, fast, reliable decisions can be made. However, their extraction is a challenge due to the necessary response time, memory and continuous model updates. In this paper, an approach for the extraction of emerging patterns in data streams is presented. It processes the instances by means of batches following an adaptive approach. The learning algorithm is an evolutionary fuzzy system where previous knowledge is employed in order to adapt to concept drift. A wide experimental study has been performed in order to show both the suitability of the approach in combating concept drift and the quality of the knowledge extracted. Finally, the proposal is applied to a case study related to the continuous determination of the profiles of New York City cab customers according to their fare amount, in order to show its potential

Nodal sampling: a new image reconstruction algorithm for SMOS

Soil moisture and ocean salinity (SMOS) brightness temperature (TB) images and calibrated visibilities are related by the so-called G -matrix. Due to the incomplete sampling at some spatial frequencies, sharp transitions in the TB scenes generate a Gibbs-like contamination ringing and spread sidelobes. In the current SMOS image reconstruction strategy, a Blackman window is applied to the Fourier components of the TBs to diminish the amplitude of artifacts such as ripples, as well as other Gibbs -like effects. In this paper, a novel image reconstruction algorithm focused on the reduction of Gibbs -like contamination in TB images is proposed. It is based on sampling the TB images at the nodal points, that is, at those points at which the oscillating interference causes the minimum distortion to the geophysical signal. Results show a significant reduction of ripples and sidelobes in strongly radio-frequency interference contaminated images. This technique has been thoroughly validated using snapshots over the ocean, by comparing TBs reconstructed in the standard way or using the nodal sampling (NS) with modeled TBs. Tests have revealed that the standard deviation of the difference between the measurement and the model is reduced around 1 K over clean and stable zones when using NS technique with respect to the SMOS image reconstruction baseline. The reduction is approximately 0.7 K when considering the global ocean. This represents a crucial improvement in TB quality, which will translate in an enhancement of the retrieved geophysical parameters, particularly the sea surface salinity.Peer ReviewedPostprint (author's final draft

ACEWATER2 Regional database: hydro-climatology data-analysis

The report presents the architecture of a regional hydro-climatology information system, developed in the framework of the ACEWATER2 project, in order to support effective organization of information. Information includes both freely available large and regional scale data sources, as well as databases compiled by the CoEs (Centers of Excellence) and submitted as part of their scientific undertakings. The information system builds upon and specializes the JRC knowledge sharing platform Aquaknow (https://aquaknow.jrc.ec.europa.eu/), including: • at the system core, a relational database; its schema has been designed to store both detailed metadata and, where relevant (avoiding duplication of information otherwise accessible), data themselves. Metadata include, among others, datasets extended description, spatial extent, temporal frequency, reference Institutions/authors, credits and limitations, web links to access original data and/or any further documentation. Data can be stored as public or private, depending upon confidentialy and sharing policies; • user friendly facilities, supporting the end user in efficiently browsing, querying, uploading and downloading information (metadata and data). System access is limited to accredited audience, via password authentication. Dedicated groups for the three ACEWATER CoE networks (Western, Southern and Central-Eastern Africa) have been setup and scientists invited to register. Currently the system is operational and we submitted databases documented and, depending upon confidentiality and authorization issues, also stored. A general review and classification of freely available information at continenal, regional and local scale of interest to ACEWATER2 project, and particularly to selected study areas (Senegal, Gambia and Niger; Zambezi; Blue Nile and Lake Victoria), have been completed. Metadata and, where relevant, data themselves have been stored to the information system database. Information submitted by the CoE (a continuous ongoing process) is migrated to the database as well, depending upon sharing authorization and/or limitations. The report also documents the ongoing scientific research at JRC on climate variability analysis based on L-Moments statistics. In particular maps of estimated precipitation deficit for different return periods at the river basins of interest are presented and included in the database.JRC.D.2-Water and Marine Resource