Theileria parva: taking control of host cell proliferation and survival mechanisms.

The intracellular parasite Theileria parva infects and transforms bovine T-cells, inducing their uncontrolled proliferation and spread in non-lymphoid as well as lymphoid tissues. This parasite-induced transformation is the predominant factor contributing to the pathogenesis of a lymphoproliferative disease, called East Coast fever. T. parva-transformed cells become independent of antigenic stimulation or exogenous growth factors. A dissection of the signalling pathways that are activated in T. parva-infected cells shows that the parasite bypasses signalling pathways that normally emanate from the T-cell antigen receptor to induce continuous proliferation. This review concentrates on the influence of the parasite on the state of activation of the mitogen-activated protein kinase (MAPK), NF-kappaB and phosphoinositide-3-kinase (PI3-K) pathways in the host cell. Of the MAPKs, JNK, but not ERK or p38, is active, inducing constitutive activation of the transcription factors AP-1 and ATF-2. A crucial step in the transformation process is the persistent activation of the transcription factor NF-kappaB, which protects T. parva-transformed cells from spontaneous apoptosis accompanying the transformation process. Inhibitor studies also suggest an important role for the lipid kinase, PI-3K, in the continuous proliferation of T. parva-transformed lymphocytes.

Pond head level control in a run-of-river hydro power plant using fuzzy controller

The run-of-river hydro power plant usually have low or nil water storage capacity, and therefore an adequate control strategy is required to keep the water level constant in pond. This paper presents a novel technique based on TSK fuzzy controller to maintain the pond head constant. The performance is investigated over a wide range of hill curve of hydro turbine. The results are compared with PI controller as discussed in [1].

Control en modo corriente y tensión eficaz con lazo de offset para inversor monofásico embarcado en aviones adecuado para funcionamiento en paralelo y conexión trifásica

La incorporación de un lazo de tensión eficaz de (RMS) es una posibilidad atractiva para el control de inversores de potencia de una manera sencilla. Si se combina con un control en modo corriente usando una sonda de efecto Hall, el ruido de modo común de la etapa de potencia transmitido al control puede ser reducido, mejorando la distorsión armónica total (THD) y manteniendo la posibilidad de operación en paralelo. Además, al estar el control de tensión definido sobre baja frecuencia (DC), obtener una gran ganancia a la frecuencia de interés (0Hz) es sencilla con control basado en PI, lo cual garantiza una onda de tensión de salida a 400Hz sin error, a costa de un peor desempeño ante transitorios y ante cargas no lineales. Sin embargo, la implementación de una estrategia de control de esta naturaleza puede provocar la aparición de offset en la salida. Por otra parte, el esquema oculta la información de la fase de la onda de tensión de salida, necesaria para sincronizar tres módulos monofásicos en un montaje trifásico. En este artículo el diseño e implementación del sistema completo es abordado, resolviendo los inconvenientes mencionados mediante un tercer lazo analógico de control para el offset y un algoritmo de sincronización implementado en una FPGA.

Current Mode with RMS Voltage and Offset Control Loops for a Single-Phase Aircraft Inverter Suitable for Parallel and 3-Phase Operation Modes

Rms voltage regulation may be an attractive possibility for controlling power inverters. Combined with a Hall Effect sensor for current control, it keeps its parallel operation capability while increasing its noise immunity, which may lead to a reduction of the Total Harmonic Distortion (THD). Besides, as voltage regulation is designed in DC, a simple PI regulator can provide accurate voltage tracking. Nevertheless, this approach does not lack drawbacks. Its narrow voltage bandwidth makes transients last longer and it increases the voltage THD when feeding non-linear loads, such as rectifying stages. On the other hand, the implementation can fall into offset voltage error. Furthermore, the information of the output voltage phase is hidden for the control as well, making the synchronization of a 3-phase setup not trivial. This paper explains the concept, design and implementation of the whole control scheme, in an on board inverter able to run in parallel and within a 3-phase setup. Special attention is paid to solve the problems foreseen at implementation level: a third analog loop accounts for the offset level is added and a digital algorithm guarantees 3-phase voltage synchronization.

Power-frequency control of hydropower plants with long penstocks in isolated systems with wind generation

In this paper the power-frequency control of hydropower plants with long penstocks is addressed. In such configuration the effects of pressure waves cannot be neglected and therefore commonly used criteria for adjustment of PID governors would not be appropriate. A second-order Π model of the turbine-penstock based on a lumped parameter approach is considered. A correction factor is introduced in order to approximate the model frequency response to the continuous case in the frequency interval of interest. Using this model, several criteria are analysed for adjusting the PI governor of a hydropower plant operating in an isolated system. Practical criteria for adjusting the PI governor are given. The results are applied to a real case of a small island where the objective is to achieve a generation 100% renewable (wind and hydro). Frequency control is supposed to be provided exclusively by the hydropower plant. It is verified that the usual criterion for tuning the PI controller of isolated hydro plants gives poor results. However, with the new proposed adjustment, the time response is considerably improved

Frequency control support of a wind-solar isolated system by a hydropower plant with long tail-race tunnel

Pumped storage hydro plants (PSHP) can provide adequate energy storage and frequency regulation capacities in isolated power systems having significant renewable energy resources. Due to its high wind and solar potential, several plans have been developed for La Palma Island in the Canary archipelago, aimed at increasing the penetration of these energy sources. In this paper, the performance of the frequency control of La Palma power system is assessed, when the demand is supplied by the available wind and solar generation with the support of a PSHP which has been predesigned for this purpose. The frequency regulation is provided exclusively by the PSHP. Due to topographic and environmental constraints, this plant has a long tail-race tunnel without a surge tank. In this configuration, the effects of pressure waves cannot be neglected and, therefore, usual recommendations for PID governor tuning provide poor performance. A PI governor tuning criterion is proposed for the hydro plant and compared with other criteria according to several performance indices. Several scenarios considering solar and wind energy penetration have been simulated to check the plant response using the proposed criterion. This tuning of the PI governor maintains La Palma system frequency within grid code requirements.

31P NMR magnetization transfer study of the control of ATP turnover in Saccharomyces cerevisiae.

31P NMR magnetization transfer measurements have been used to measure the steady state flux between Pi and ATP in yeast cells genetically modified to overexpress an adenine nucleotide translocase isoform. An increase in Pi -> ATP flux and apparent ratio of moles of ATP synthesized/atoms of oxygen consumed (P:O ratio), when these cells were incubated with glucose, demonstrated that the reactions catalyzed by the translocase and F1F0 ATP synthase were readily reversible in vivo. However, when the same cells were incubated with ethanol alone, translocase overexpression had no effect on the measured Pi -> ATP flux or apparent P:O ratio, suggesting that the synthase was now operating irreversibly. This change was accompanied by an increase in the intracellular ADP concentration. These observations are consistent with a model proposed for the kinetic control of mitochondrial ATP synthesis, which was based on isotope exchange measurements with isolated mammalian mitochondria [LaNoue, K. F., Jeffries, F. M. H. & Radda, G. K. (1986) Biochemistry 25, 7667-7675].

Interfaz software/hardware entre Raspberry Pi y FPGA Spartan-6 y su aplicación a simulación dirigida por eventos

Hoy día vivimos en la sociedad de la tecnología, en la que la mayoría de las cosas cuentan con uno o varios procesadores y es necesario realizar cómputos para hacer más agradable la vida del ser humano. Esta necesidad nos ha brindado la posibilidad de asistir en la historia a un acontecimiento sin precedentes, en el que la cantidad de transistores era duplicada cada dos años, y con ello, mejorada la velocidad de cómputo (Moore, 1965). Tal acontecimiento nos ha llevado a la situación actual, en la que encontramos placas con la capacidad de los computadores de hace años, consumiendo muchísima menos energía y ocupando muchísimo menos espacio, aunque tales prestaciones quedan un poco escasas para lo que se requiere hoy día. De ahí surge la idea de comunicar placas que se complementan en aspectos en las que ambas se ven limitadas. En nuestro proyecto desarrollaremos una interfaz s oftware/hardware para facilitar la comunicación entre dos placas con distintas prestaciones, a saber, una Raspberry Pi modelo A 2012 y una FPGA Spartan XSA3S1000 con placa extendida XStend Board V3.0. Dicha comunicación se basará en el envío y recepción de bits en serie, y será la Raspberry Pi quien marque las fases de la comunicación. El proyecto se divide en dos partes: La primera parte consiste en el desarrollo de un módulo para el kernel de Linux, que se encarga de gestionar las entradas y salidas de datos de la Raspberry Pi cuando se realizan las pertinentes llamadas de write o read. Mediante el control de los GPIO y la gestión de las distintas señales, se realiza la primera fase de la comunicación. La segunda parte consiste en el desarrollo de un diseño en VHDL para la FPGA, mediante el cual se pueda gestionar la recepción, cómputo y posterior envío de bits, de forma que la Raspberry Pi pueda disponer de los datos una vez hayan sido calculados. Ambas partes han sido desarrolladas bajo licencias libres (GPL) para que estén disponibles a cualquier persona interesada en el desarrollo y que deseen su reutilización.

Control and navigation of a rover for agricultural purposes

L’obiettivo di questa tesi è di descrivere e implementare via software un modello di rover autonomo per uso in ambito agricolo. La scelta di questo argomento deriva dal fatto che al laboratorio CASY dell’Università di Bologna è stato commissionato un robot che possa aiutare piccoli imprenditori agricoli a essere competitivi con i più grandi. Le funzionalità che il robot avrà, una volta ultimato, andranno dal tagliare l’erba allo spruzzare fertilizzante sugli alberi da frutto. Questa tesi si interessa del progetto del sistema di navigazione. Inizialmente viene introdotto il modello cinematico e in particolare la configurazione differential drive in cui il rover rientra. Successivamente viene elaborato un sistema di controllo basato sulla linearizzazione statica del feedback. Una volta completati il modello e il sistema di controllo si procede con la generazione di traiettoria: vengono analizzati e confrontati alcuni algoritmi per l’inseguimento di una traiettoria definita tramite waypoint. Infine è presentato un algoritmo per la navigazione all’interno di un campo di filari di alberi da frutto. Le uniche informazioni esterne disponibili in questo contesto sono le rilevazioni di sensori di distanza frontali e laterali, in quanto un GPS sarebbe troppo impreciso per gli scopi. Questa tesi costituisce la base per ulteriori sviluppi del progetto. In particolare la realizzazione di un programma di supervisione che stabilisca la modalità di moto da attuare e programmi specifici per le varie funzionalità agricole del rover.

Robust multivariable control of complex biological processes

This paper addresses advanced control of a biological nutrient removal (BNR) activated sludge process. Based on a previously validated distributed parameter model of the BNR activated sludge process, we present robust multivariable controller designs for the process, involving loop shaping of plant model, robust stability and performance analyses. Results from three design case studies showed that a multivariable controller with stability margins of 0.163, 0.492 and 1.062 measured by the normalised coprime factor, multiplicative and additive uncertainties respectively give the best results for meeting performance robustness specifications. The controller robustly stabilises effluent nutrients in the presence of uncertainties with the behaviour of phosphorus accumulating organisms as well as to effectively attenuate major disturbances introduced as step changes. This study also shows that, performance of the multivariable robust controller is superior to multi-loops SISO PI controllers for regulating the BNR activated sludge process in terms of robust stability and performance and controlling the process using inlet feed flowrate is infeasible. (C) 2003 Elsevier Ltd. All rights reserved.

APP controls the formation of PI(3,5)P2 vesicles through its binding of the PIKfyve complex

Phosphoinositides are signalling lipids that are crucial for major signalling events as well as established regulators of membrane trafficking. Control of endosomal sorting and endosomal homeostasis requires phosphatidylinositol-3-phosphate (PI(3)P) and phosphatidylinositol-3,5-bisphosphate (PI(3,5)P2), the latter a lipid of low abundance but significant physiological relevance. PI(3,5)P2 is formed by phosphorylation of PI(3)P by the PIKfyve complex which is crucial for maintaining endosomal homeostasis. Interestingly, loss of PIKfyve function results in dramatic neurodegeneration. Despite the significance of PIKfyve, its regulation is still poorly understood. Here we show that the Amyloid Precursor Protein (APP), a central molecule in Alzheimer’s disease, associates with the PIKfyve complex (consisting of Vac14, PIKfyve and Fig4) and that the APP intracellular domain directly binds purified Vac14. We also show that the closely related APP paralogues, APLP1 and 2 associate with the PIKfyve complex. Whether APP family proteins can additionally form direct protein–protein interaction with PIKfyve or Fig4 remains to be explored. We show that APP binding to the PIKfyve complex drives formation of PI(3,5)P2 positive vesicles and that APP gene family members are required for supporting PIKfyve function. Interestingly, the PIKfyve complex is required for APP trafficking, suggesting a feedback loop in which APP, by binding to and stimulating PI(3,5)P2 vesicle formation may control its own trafficking. These data suggest that altered APP processing, as observed in Alzheimer’s disease, may disrupt PI(3,5)P2 metabolism, endosomal sorting and homeostasis with important implications for our understanding of the mechanism of neurodegeneration in Alzheimer’s disease.

LPJ-LMfire simulations for Europe for the Last Glacial Maximum and preindustrial control, link to netCDF files

This data sets contains LPJ-LMfire dynamic global vegetation model output covering Europe and the Mediterranean for the Last Glacial Maximum (LGM; 21 ka) and for a preindustrial control simulation (20th century detrended climate). The netCDF data files are time averages of the final 30 years of the model simulation. Each netCDF file contains four or five variables: fractional cover of 9 plant functional types (PFTs; cover), total fractional coverage of trees (treecover), population density of hunter-gatherers (foragerPD; only for the "people" simulations), fraction of the gridcell burned on 30-year average (burnedf), and vegetation net primary productivity (NPP). The model spatial resolution is 0.5-degrees For the LGM simulations, LPJ-LMfire was driven by the PMIP3 suite of eight GCMs for which LGM climate simulations were available. Also provided in this archive is the result of an LPJ-LMfire run that was forced by the average climate of all GCMs (the "GCM-mean" files), and the average of each of the individual LPJ-LMfire runs over the eight LGM scenarios individually (the "LPJ-mean" files). The model simulations are provided that include the influence of human presence on the landscape (the "people" files), and in a "world without humans" scenario (the "natural" files). Finally this archive contains the preindustrial reference simulation with and without human influence ("PI_reference_people" and "PI_reference_nat", respectively). There are therefore 22 netCDF files in this archive: 8 each of LGM simulations with and without people (total 16) and the "GCM mean" simulation (2 files) and the "LPJ mean" aggregate (2 files), and finally the two preindustrial "control" simulations ("PI"), with and without humans (2 files). In addition to the LPJ-LMfire model output (netCDF files), this archive also contains a table of arboreal pollen percent calculated from pollen samples dated to the LGM at sites throughout (lgmAP.txt), and a table containing the location of archaeological sites dated to the LGM (LGM_archaeological_site_locations.txt).

Control of the innate immune response by the mevalonate pathway.

Deficiency in mevalonate kinase (MVK) causes systemic inflammation. However, the molecular mechanisms linking the mevalonate pathway to inflammation remain obscure. Geranylgeranyl pyrophosphate, a non-sterol intermediate of the mevalonate pathway, is the substrate for protein geranylgeranylation, a protein post-translational modification that is catalyzed by protein geranylgeranyl transferase I (GGTase I). Pyrin is an innate immune sensor that forms an active inflammasome in response to bacterial toxins. Mutations in MEFV (encoding human PYRIN) result in autoinflammatory familial Mediterranean fever syndrome. We found that protein geranylgeranylation enabled Toll-like receptor (TLR)-induced activation of phosphatidylinositol-3-OH kinase (PI(3)K) by promoting the interaction between the small GTPase Kras and the PI(3)K catalytic subunit p110δ. Macrophages that were deficient in GGTase I or p110δ exhibited constitutive release of interleukin 1β that was dependent on MEFV but independent of the NLRP3, AIM2 and NLRC4 inflammasomes. In the absence of protein geranylgeranylation, compromised PI(3)K activity allows an unchecked TLR-induced inflammatory responses and constitutive activation of the Pyrin inflammasome.