Controlability of higher order linear systems

Theory and equations on complete controllability of higher order linear system

Design-Based Treatment of Unit Nonresponse by the Calibration Approach

The use of nonresponse calibration weighting is considered in a complete design-based frameworkto account for the cases in which nonresponse is a fixed characteristic of the units, just like the interest variable. Approximate expressions of design-based bias and variance of the calibration estimator are derived and some estimators of the sampling variance are proposed. The choice of auxiliary variables is discussed from theoretical and practical point of view. The results of an extensive simulation study demonstrate how the reliability of the procedure is mainly determined by the capability of selecting auxiliary variables in such a way that their relationship with the interest variable is similar for both the respondent and nonrespondent sub-populations.auxiliary variables, calibration estimator, variance estimator, simulation study.

La Piezosurgery come metodica alternativa alla strumentazione rotante tradizionale nell'estrazione di ottavi inferiori inclusi. Revisione della letteratura

La presente dissertazione si occupa di esporre la validità della piezosurgery nell'estrazione di ottavi inclusi inferiori come alternativa alla strumentazione rotante tradizionale. Ne vengono illustrati vantaggi e svantaggi con particolare attenzione al tempo impiegato per l'intervento, alla riduzione delle complicanze e al miglioramento del decorso postoperatorio, il tutto sulla base di una revisione sistematica che la letteratura propone su questo argomento corredata dall' esposizione di una serie di casi clinici

Studying the targeting of frustule-associated proteins in the centric diatom Thalassiosira pseudonana

Diatoms are unicellular and photosynthetic organisms of highest ecological relevance. They are very well known because of their ability to exploit the dissolved silica available in the water to synthetize a modified cell wall, called the frustule. The frustule has a specific morphology for each species, and its formation process is complex and strictly intertwined with cell division, and therefore with the cell cycle. The diatom T. pseudonana has a strongly silicified frustule and is the first diatom species whose genome was sequenced, in 2004; since then, it has been the subject of many biomineralization studies and several proteins involved in the formation of the frustule, such as the silaffins and the cingulins, have been described, characterized, and localized in vivo. These proteins are believed to enter the secretory pathway at the ER, from which are then transported via vesicles to the Golgi, and from there to the silica deposition vesicle (SDV). When the synthesis of the frustule components inside the SDV is completed, its content is exocytosed outside of the cell. The only published study on the targeting of frustule proteins in T. pseudonana had identified short stretches of amino acids called pentalysine clusters (PLC) as potential targeting signal to the frustule of silaffins. Here, I have investigated the targeting of two cingulin representatives (CinW2 and CinY2) and one silaffins (Sil3) following different approaches: first, I have studied whether the presence of PLC-like regions in cingulins (called lysine-enriched regions (or LERs)) indicate that these regions play a similar role as it was for the PLC of silaffins; I have also studied if it was possible to identify a clear valve- or girdle band-targeting signal and, in that case, if this signal could be used to direct a valve-protein to the girdle or vice versa; second, since there is a remarkable difference in the gene expression between frustule-associated protein-encoding genes, I have investigated if the transcriptional regulation of the genes can affect the targeting of the encoded proteins; in parallel, I have obtained preliminary results regarding the isolation of the promoters of sil3, cinW2, cinY2. Additionally, I have identified unknown frustule proteins based on the presence of a PLC-like regions as well as a new discovered motif

EIN2 and COI1 control the antagonism between ethylene and jasmonate in adventitious rooting of Arabidopsis thaliana thin cell layers

Auxins induce adventitious roots (ARs) in numerous culture-systems, and indole-3-butyric acid (IBA) is frequently the best AR-inducer. Vitamin requirements vary according to species, explant, and culture-conditions. Arabidopsis thaliana thin cell layers (AtTCLs) are uncapable of AR-formation on hormone-free medium containing thiamine and myo-inositol, whereas ARs are induced when IBA (10 μM), with/without kinetin (Kin, 0.1 μM), is added. The research frst aim was to determine whether a synergism between IBA and myo-inositol and thiamine was necessary for AR-formation. Results showed that IBA induced AR-formation without myo-inositol and thiamine, but better when both vitamins were also present. Deciphering hormonal action on AR formation under optimal vitamin content would be essential for improving the AR process. Ethylene (ET)/jasmonic acid (JA) signaling cross-talk has been demonstrated as being involved in AR-formation in IBA+Kincultured AtTCLs, by using ein3eil1 and coi1-16 mutants. ETHYLENE INSENSITIVE3 (EIN3)/EIN3-LIKE1 (EIL1) are positive regulators of ethylene (ET)-signaling, whereas CORONATINE INSENSITIVE1 (COI1) is involved in JA-signaling. The ETHYLENE INSENSITIVE2 (EIN2) protein activates EIN3/EIL1 in ET-presence. To understand whether EIN2 was also involved, the AR-response of ein2-1 and coi1-16 TCLs was evaluated adding the ET-precursor 1-aminocyclopropane1-carboxylic acid (ACC, 0.1 μM) and/or the JA-donor methyl jasmonate (JAMe, 0.01 μM) to IBA+vitamins-containing medium. AR-formation was enhanced by JAMe, reduced by ACC, but unchanged by JAMe+ACC in the wild type TCLs, whereas remained similarly low in ein2-1 and coi1-16 under all treatments. Collectively, these results demonstrate that the antagonism between JA and ET in AR-formation from AtTCLs involves a cross-talk by EIN2 and COI1

Fish parasites resolve the paradox of missing coextinctions.

Models of coextinction identify parasites as one of the most menaced ecological groups. The number of host species a parasite uses should strongly affect its risk of coextinction. The naïve expectation is that the lower the number, the higher is the parasite's risk of being left with no hosts. Here we analyse the coextinction risk of 12,141 fish parasite species and find that highly specific parasites are not the most endangered, because they tend to use hosts with low vulnerability to extinction. This unexpected result may explain why the number of documented host-parasite coextinctions is much lower than predicted by theoretical studies. © 2013 Macmillan Publishers Limited. All rights reserved