Model current-mode control with ease and accuracy

Current-mode control (CMC) is widely used in dc-dc converters for high-performance applications. In spite of its implementation simplicity, the dynamics are complicated and designing the control loop can be challenging. Many research efforts in the last two decades have refined dynamic models that capture the most relevant aspects of the controller behavior. Today’s designers can choose from a vast pool of theoretical resources when developing a CMC solution. A new model is being proposed that maximizes the advantages of the most popular model, while improving on its weaknesses. This model is based on already existing models but outperforms them in the design practice

Effect of Carbon Dioxide Concentration on the Growth Response of Chlorella vulgaris Under Four Different Led Illumination

This experiment examined the growth response of Chlorella vulgaris exposed to CO2 concentrations increasing from ambient to 8.5% and under white, blue, red and red-blue lights after 15 days incubation. Biomass production increased with increasing CO2 concentrations under all light sources. The highest biomass production, 1.59 g L-1, was obtained when the algae were supplied with 8.5% CO2 and exposed to white light. Biomass production under blue, red and red+blue light was 1.53 g L-1, 0.45 g L-1 and 1.27 g L-1, respectively. The research suggests that C. vulgaris is not able to adapt production of its photosynthetic pigments to absorb light sources different that it is normally has evolved to

Deficiencias judiciales que se encuentran en los procesos adelantados por el delito de violencia intrafamiliar en el Derecho Penal en Colombia.

Es fundamental en la presente investigación revisar las deficiencias existentes en los procesos adelantados por la Fiscalía General de la Nación por el punible de violencia intrafamiliar, un proceso que ha tenido desde su creación polémica tanto social y política. Por ende, se requiere identificar la inconformidad de las partes del proceso que tiene como objetivo defender la integridad y la vida de los integrantes de la familia, de quienes hacen parte del núcleo familiar. Conforme a ello, se revisaran todos los documentos recuperados en diferentes fuentes del derecho, y los repositorios de universidades nacionales e internacionales.Facultad de Derecho Universidad Libre - Especialización en Derecho PenalIt is fundamental in the present investigation to review the existing deficiencies in the processes carried out by the Attorney General of the Nation for the punishable crime of intrafamily violence, a process that has had both social and political controversy since its creation. Therefore, it is necessary to identify the disagreement of the parties in the process that aims to defend the integrity and life of the family members, of those who are part of the family nucleus. Accordingly, all the documents recovered in different sources of law, and the repositories of national and international universities will be reviewed

Deficiencias judiciales que se encuentran en los procesos adelantados por el delito de violencia intrafamiliar en el Derecho Penal en Colombia.

Es fundamental en la presente investigación revisar las deficiencias existentes en los procesos adelantados por la Fiscalía General de la Nación por el punible de violencia intrafamiliar, un proceso que ha tenido desde su creación polémica tanto social y política. Por ende, se requiere identificar la inconformidad de las partes del proceso que tiene como objetivo defender la integridad y la vida de los integrantes de la familia, de quienes hacen parte del núcleo familiar. Conforme a ello, se revisaran todos los documentos recuperados en diferentes fuentes del derecho, y los repositorios de universidades nacionales e internacionales.Universidad Libre Facultad de Derecho - Especializacion en Derecho Penal y CriminologiaIt is fundamental in the present investigation to review the existing deficiencies in the processes carried out by the Attorney General of the Nation for the punishable crime of intrafamily violence, a process that has had both social and political controversy since its creation. Therefore, it is necessary to identify the disagreement of the parties in the process that aims to defend the integrity and life of the family members, of those who are part of the family nucleus. Accordingly, all the documents recovered in different sources of law, and the repositories of national and international universities will be reviewed

Instructive conductive 3D silk foam-based bone tissue scaffolds enable electrical stimulation of stem cells for enhanced osteogenic differentiation

Stimuli-responsive materials enabling the behaviour of the cells that reside within them to be controlled are vital for the development of instructive tissue scaffolds for tissue engineering. Herein we describe the preparation of conductive silk foam-based bone tissue scaffolds that enable the electrical stimulation of human mesenchymal stem cells to enhance their differentiation towards osteogenic outcomes

Quantification of Optic Disc Edema during Exposure to High Altitude Shows No Correlation to Acute Mountain Sickness

BACKGROUND: The study aimed to quantify changes of the optic nerve head (ONH) during exposure to high altitude and to assess a correlation with acute mountain sickness (AMS). This work is related to the Tuebingen High Altitude Ophthalmology (THAO) study. METHODOLOGY/PRINCIPAL FINDINGS: A confocal scanning laser ophthalmoscope (cSLO, Heidelberg Retina Tomograph, HRT3®) was used to quantify changes at the ONH in 18 healthy participants before, during and after rapid ascent to high altitude (4559 m). Slitlamp biomicroscopy was used for clinical optic disc evaluation; AMS was assessed with Lake Louise (LL) and AMS-cerebral (AMS-c) scores; oxygen saturation (SpO₂) and heart rate (HR) were monitored. These parameters were used to correlate with changes at the ONH. After the first night spent at high altitude, incidence of AMS was 55% and presence of clinical optic disc edema (ODE) 79%. Key stereometric parameters of the HRT3® used to describe ODE (mean retinal nerve fiber layer [RNFL] thickness, RNFL cross sectional area, optic disc rim volume and maximum contour elevation) changed significantly at high altitude compared to baseline (p<0.05) and were consistent with clinically described ODE. All changes were reversible in all participants after descent. There was no significant correlation between parameters of ODE and AMS, SpO₂ or HR. CONCLUSIONS/SIGNIFICANCE: Exposure to high altitude leads to reversible ODE in the majority of healthy subjects. However, these changes did not correlate with AMS or basic physiologic parameters such as SpO₂ and HR. For the first time, a quantitative approach has been used to assess these changes during acute, non-acclimatized high altitude exposure. In conclusion, ODE presents a reaction of the body to high altitude exposure unrelated to AMS

Cell tracking in cardiac repair: what to image and how to image

Stem cell therapies hold the great promise and interest for cardiac regeneration among scientists, clinicians and patients. However, advancement and distillation of a standard treatment regimen are not yet finalised. Into this breach step recent developments in the imaging biosciences. Thus far, these technical and protocol refinements have played a critical role not only in the evaluation of the recovery of cardiac function but also in providing important insights into the mechanism of action of stem cells. Molecular imaging, in its many forms, has rapidly become a necessary tool for the validation and optimisation of stem cell engrafting strategies in preclinical studies. These include a suite of radionuclide, magnetic resonance and optical imaging strategies to evaluate non-invasively the fate of transplanted cells. In this review, we highlight the state-of-the-art of the various imaging techniques for cardiac stem cell presenting the strengths and limitations of each approach, with a particular focus on clinical applicability

Com o diabo no corpo: os terríveis papagaios do Brasil colônia

Desde a Antiguidade, papagaios, periquitos e afins (Psittacidae) fascinaram os europeus por seu vivo colorido e uma notável capacidade de interação com seres humanos. A descoberta do Novo Mundo nada faria além de acrescentar novos elementos ao tráfico de animais exóticos há muito estabelecido pelos europeus com a África e o Oriente. Sem possuir grandes mamíferos, a América tropical participaria desse comércio com o que tinha de mais atrativo, essencialmente felinos, primatas e aves - em particular os papagaios, os quais eram embarcados em bom número. Contudo, a julgar pelos documentos do Brasil colônia, esses voláteis podiam inspirar muito pouca simpatia, pois nenhum outro animal - exceto as formigas - foi tantas vezes mencionado como praga para a agricultura. Além disso, alguns psitácidas mostravam-se tão loquazes que inspiravam a séria desconfiança de serem animais demoníacos ou possessos, pois só três classes de entidades - anjos, homens e demônios - possuíam o dom da palavra. Nos dias de hoje, vários representantes dos Psittacidae ainda constituem uma ameaça para a agricultura, enquanto os indivíduos muito faladores continuam despertando a suspeita de estarem possuídos pelo demônio. Transcendendo a mera curiosidade, essa crença exemplifica o quão intrincadas podem ser as relações do homem com o chamado “mundo natural”, revelando um universo mais amplo e multifacetado do que se poderia supor a princípio. Nesse sentido, a existência de aves capazes de falar torna essa relação ainda mais complexa e evidencia que as dificuldades de estabelecer o limite entre o animal e o humano se estendem além dos primatas e envolvem as mais inusitadas espécies zoológicas.Since ancient times, parrots and their allies (Psittacidae) have fascinated Europeans by their striking colors and notable ability to interact with human beings. The discovery of the New World added new species to the international exotic animal trade, which for many centuries had brought beasts to Europe from Africa and the Orient. Lacking large mammals, tropical America participated in this trade with its most appealing species, essentially felines, primates and birds - especially parrots - which were shipped in large numbers. It should be noted, however, that at times these birds were not well liked. In fact, according to documents from colonial Brazil, only the ants rank higher than parrots as the animals most often mentioned as agricultural pests. On the other hand, some of these birds were so chatty that people suspected them to be demonic or possessed animals, since only three classes of beings - angels, men and demons - have the ability to speak. Nowadays, several Psittacidae still constitute a threat to agriculture, and the suspicion that extremely talkative birds were demon possessed has also survived. More than a joke or a mere curiosity, this belief exemplifies how intricate man’s relationships with the “natural world” may be. In this sense, the existence of birds that are able to speak adds a further twist to these relationships, demonstrating that the problem of establishing a boundary between the animal and the human does not only involve primates, but also includes some unusual zoological species

Constraining authigenic and diagenetic processes in Fe-rich lacustrine sediments using proxies of paleoredox conditions

Paleoclimate reconstructions using lake sediments are based on the study of climate proxies. This thesis explores the potential of Fe-minerals to record climate-driven processes and their stability throughout burial and reevaluates Rock-Eval pyrolysis to asses organic matter-related proxies, using End-Member Analysis. We described the Fe-mineral assemblage through sequential extraction in a 100 meters-long core from lake Towuti, Indonesia, and from a 40 centimeters-long core from lake Fagnano, Argentina. We investigated the coevolution of chemical and isotopic signatures (δ56Fe) in reactive ferric (Fe-(oxyhydr)oxides) and ferrous (siderite and magnetite) phases. The isotopic correlation between ferric and ferrous phases in Towuti sediments reveals slow dissolution of Fe-oxides and the formation of diagenetic siderite. The high mobility of iron during diagenesis limits its use as a proxy for water column redox conditions. These transformations can substantially occur at the redox boundary, a few centimeters below the sediment surface, as in lake Fagnano