Design of a 77-GHz LC-VCO With a Slow-Wave Coplanar Stripline-Based Inductor

International audienc

Sistema tracionador de intervenção compreendendo um umbilical

PETROBRASUniversidade Federal do Rio Grande do SulEngenhariaInformáticaDepositad

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

Canagliflozin and renal outcomes in type 2 diabetes and nephropathy

BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodium–glucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to <90 ml per minute per 1.73 m2 of body-surface area and albuminuria (ratio of albumin [mg] to creatinine [g], >300 to 5000) and were treated with renin–angiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of <15 ml per minute per 1.73 m2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P<0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P<0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years

Caractérisation expérimentale et modélisation cyclostationnaire des sources de bruit BF dans les composants semiconducteurs pour la CAO des circuits MMIC non linéaires

Ce travail concerne le développement de moyens de caractérisation expérimentale du bruit BF des composants semiconducteurs. Pour pouvoir extraire les sources de bruit en courant équivalentes aux accès du transistor lorsque celui-ci est soumis à un fort courant DC, nous proposons une méthode basée sur la caractérisation expérimentale de sa dynamique BF, ainsi que des fluctuations de tensions à ses bornes. Dans un deuxième temps, nous avons étudié le bruit BF des diodes et transistors, lorsque ceux-ci sont soumis à un régime de travail fort signal. L instrumentation retenue pour cette étude a été préalablement utilisée dans la mesure du bruit 1/f des résistances au carbone, afin de démontrer ses potentialités. Les résultats obtenus sur des composants semiconducteurs ont mis en évidence le caractère cyclostationnaire des sources de bruit BF.This work concerns the development of an experimental technique to characterize the low-frequency noise of semiconductor devices. In order to extract the equivalent short-circuit current noise sources of a transistor operated under high DC current densities, we propose a method based on the experimental determination of the low-frequency dynamics of the device, followed by the measurement of the voltage fluctuations across its terminals. We also studied the behavior of the low-frequency noise of diodes and transistors, when those devices are forced into large-signal operation. The instrumentation retained for this study had been previously used to measure the 1/f noise of carbon resistors, as a mean of exploring the potentialities of the setup. The results obtained from resistors, diodes and transistos give a strong evidence of the clyclostationary properties of the low-frequency noise.LIMOGES-BU Sciences (870852109) / SudocSudocFranceF

A Methodology to Characterize the Low-Frequency Noise of InP Based Transistors

International audienceThis paper describes a methodology to measure the low-frequency noise of InP-based transistors. These transistors have demonstrated transition frequencies (ft) greater than 200 GHz, generally achieved at current densities in excess of 200 kA/cm2. Depending on the DC current gain, this may represent base currents of some mA. For the first time, curves of Sib, Sic and Sibic for base currents of up to 3 mA are demonstrated, in excellent agreement with those obtained from one-port measurements. This is only possible with an accurate experimental characterisation of the small-signal parameters of the transistor, which are frequency-dependent due to self-heating

Dual approach for bipolar transistor thermal impedance determination

International audienceThis paper presents a dual approach for a coherent determination and validation of heterostructure bipolar transistor (HBT) thermal impedance. This study relies both on an experimental characterization method and a 3D finite element simulation approach. One section reminds briefly the experimental approach. Another describes the 3D device modeling used for the physics-based thermal simulation. Thereafter, details on the reduction method used for the numerical computation of the thermal impedance are given. As complement to pure thermal simulation, an electrothermal distributed model is proposed and gives an interpretation of the distributed effects in multi-finger devices