Evaluation of Satellite Retrievals of Chlorophyll-a in the Arabian Gulf

The Arabian Gulf is a highly turbid, shallow sedimentary basin whose coastal areas have been classified as optically complex Case II waters (where ocean colour sensors have been proved to be unreliable). Yet, there is no such study assessing the performance and quality of satellite ocean-colour datasets in relation to ground truth data in the Gulf. Here, using a unique set of in situ Chlorophyll-a measurements (Chl-a; an index of phytoplankton biomass), collected from 24 locations in four transects in the central Gulf over six recent research cruises (2015–2016), we evaluated the performance of VIIRS and other merged satellite datasets, for the first time in the region. A highly significant relationship was found (r = 0.795, p < 0.001), though a clear overestimation in satellite-derived Chl-a concentrations is evident. Regardless of this constant overestimation, the remotely sensed Chl-a observations illustrated adequately the seasonal cycles. Due to the optically complex environment, the first optical depth was calculated to be on average 6–10 m depth, and thus the satellite signal is not capturing the deep chlorophyll maximum (DCM at ~25 m). Overall, the ocean colour sensors’ performance was comparable to other Case II waters in other regions, supporting the use of satellite ocean colour in the Gulf. Yet, the development of a regional-tuned algorithm is needed to account for the unique environmental conditions of the Gulf, and ultimately provide a better estimation of surface Chl-a in the region

Harmonic Distortion Reduction of Transformer-Less Grid-Connected Converters by Ellipsoidal-Based Robust Control

A photovoltaic generator connected to a large network and supplying a nonlinear load (source of harmonics) injects distorted current into the grid. This manuscript presents an invariant-ellipsoid set design of a robust controlled active power filter to inject current into the large grid with minimum total harmonic distortion (THD). The nonlinear load current is considered an external disturbance to minimize its effect on the injected grid current. Moreover, the large grid is modeled as a fixed voltage source in a series with a Thevenin impedance whose value changes within an interval. Using the invariant-ellipsoid technique, the problem is cast as a robust disturbance-rejection tracking control. The volume of the ellipsoid is minimized, which results in minimizing the effect of disturbance on system performance and keeping the trajectories as close as possible to the origin. The design is cast into a set of nonlinear matrix inequalities that are linearized by fixing a scalar. The resulting convex optimization is solved iteratively by linear matrix inequalities (LMIs). The simulation and experimental findings show that the proposed design is successful in reducing THD injected into the grid when grid impedance is uncertain and variable loads are applied (balanced and unbalanced cases)

EVALUATION OF THE APPLICABILITY OF A TURBULENT WAKE INLET BOUNDARY CONDITION

With the objective of reducing the computational cost of the iterative processes of aerodynamic components design, tests were carried out to study under what conditions, and with what difference, only part of the calculation domain can be solved using as input information obtained from complete simulations already solved. An experimental study of an airfoil exposed to the wake interference of an upstream airfoil at a Reynolds number of 150,000 was used to verify the solutions of the Reynolds-Averaged Navier-Stokes equations solved applying the k-ω Shear Stress Transport model for turbulence closure. A Grid Convergence Index study was performed to verify if the solution of the equations for the adopted discretization leads to results within the asymptotic range. With the physical coherence of the numerical methodology verified, comparisons between the simulations with the domain comprising the two airfoils and the domain comprising only the downstream airfoil were performed. Computational time reductions in the order of 40% are observed. The differences in the aerodynamic coefficients for the two types of simulation are presented as a function of distances non-dimensionalized by the characteristic length of the body that disturbs the flow forming the wake, showing that the difference between the two methods was inversely proportional to the distance between the two bodies. Behavior that was maintained until a point where the simulation diverges, equivalent to 25% of the characteristic length of the body that generates the wake

Model-based Predictions of the Influence of Circadian Clock Genes Knock-Outs on the Cell Cycle

The existence of links between the cell division cycle and the circadian clock has been recently discovered. In this research report, we perform a small in silico analysis of how mutations on the clock genes composing the mammalian circadian clock affect the phenotype of the cell cycle. For this purpose, we use a coupled model of the mammalian circadian clock and the mammalian cell cycle where the latter one is entrained by the former one via a common protein kinase WEE1. Our in silico experiments exploit the modeling environment BIOCHAM

Herpes simplex virus ICP27 protein directly interacts with the nuclear pore complex through NUP62, inhibiting host nucleocytoplasmic transport pathways

The herpes simplex virus ICP27 protein is important for the expression and nuclear export of viral mRNAs. Although several binding sites have been mapped along the ICP27 sequence for various RNA and protein partners including the transport receptor TAP of the host cell nuclear transport machinery, several aspects of ICP27 trafficking through the nuclear pore complex remain unclear. We investigated if ICP27 could interact directly with the nuclear pore complex itself, finding that ICP27 directly binds the core nucleoporin Nup62. This is confirmed through co-immunoprecipitation and in vitro binding assays with purified components. Mapping with ICP27 deletion and point mutants further shows that the interaction requires sequences in both the N and C-termini of ICP27. Expression of wildtype ICP27 protein inhibited both classical, importin α/β-dependent and transportin dependent nuclear import. In contrast, an ICP27 point mutant that does not interact with Nup62 had no such inhibitory effect. We suggest that ICP27 association with Nup62 provides additional binding sites at the nuclear pore for ICP27 shuttling thus supporting ICP27-mediated transport. We propose that ICP27 competes with some host cell transport receptors for binding, resulting in inhibition of those host transport pathways

Wearing the Blue Tie: A study on the lived experience of Year 12 prefects in an Australian independent school

This thesis is a phenomenological study of the lived experience of 13 Year 12 students appointed as prefects (a formal leadership position) at an independent (non-government) school in urban Australia. Five staff members also provided details of their experience of prefects' student leadership. Whilst leadership has been studied extensively, student leadership has received relatively little attention. Two research questions were addressed: (1) How do student leaders experience being prefects? and, (2) How do teachers and school administrators experience student leadership? The first research question had three subsidiary questions: (i) How do prefects understand leadership? (ii) How do students experience the selection process, training and support they receive in their role as prefects? (iii) What impact does being a prefect have on the students themselves, and their relationships with their peers and teachers? Two subsidiary questions supported the second research question: (i) How do teachers experience the selection process, training and support of the prefects? (ii) How do teachers view the activities of the prefects? Synergetic focus groups, where groups self-facilitated a discussion rather than had a moderator, were used to gather data of the participants' experience of student leadership. Student participants also provided written anecdotes and artistic representations of their experiences of student leadership. A five-step process was used to analyse the data obtained from the participants. After listening to sound recordings of the sessions and reading the transcripts, units of meaning were identified from the data and grouped into clusters. Themes and meta-themes were then identified and linked to the research questions. The four meta-themes which emerged from the student data were:(i) traits of leaders, (ii) understandings of leadership, (iii) selection, training and functioning of prefects, and iv) the experience of being a prefect. Two meta-themes,(i) selection and training of prefects and (ii) understanding student leadership, emerged from the staff data. Recommendations to the school included that the training and supervision of prefects should be ongoing and that a more formalised mentoring program should be provided. Future research could consider how young people who are not leaders experience the leadership of their peers

O percevejo bronzeado Thaumastocoris peregrinus: uma ameaça à eucaliptocultura mundial.

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