Variaus e nergeric particles in rh e space radia~ (íon environmenr C. 1.11 inreracr with silicon (Q cause undcsirable effects. When a single heavy ion strikes sili col1, ir loses irs energy by crea rin g frc e elcc rro n-hole pairs, resu]r ing in a dense ionized rrack in the local region. Protons and neurrons can cause nuclear imcracrions wh en pass ing through rhe material. The rccail a150 prod uces ionizar ian , which generates a tran sic nt current pulse (har can cau se an upset wh en ilHe rprered as a signal in eh e circuic. With technology sca ling imo deepsubmi cron dimens ions, the efreccs of energetic particle h its become a co nce rn even at sea levei, wh ere rhe major hi gh-e nergy radiarion source is atmospheric neurrons and prorons.A singlc partide can hit eirh er the sequentiaJ logic ar rhe combinarionallogic in th e silicon. When an energetic partide strikes one of a memory cell 's sens itive sires, the effect ca n produce an inversion in th e srored value-in oeher words, a bit Aip in rhe memory ceU. This is called a single-evem upset (SEU) .2 Whe n an energeri c particle hits a se nsitive site in rhe com bi national logic block, ir also generates a rransiem currem pulse. This phenomenon is
called a single-evem rran sieIH (SET).3 ForPublished by the IEEE Computer Society combinational logi c bloc ks with reg istered outputs, the SET can evemually appear at rh e inpur of th e Aip-Aops placed at the com b inationallogic ourpurs, u nless t he induced rransie m pulse is e it he r 10gica1l y or electricall y masked by t he logic inpurs. If interpreted as a valid signal in che register inpU[, rhi s SET ca n cause an in co rrect valu e to be srored in th e register, provoking a soft crro r.Conrinuous rechno logy evo lu ri o n and small e r rransiswr featu res have made so ft errors on dev ices more frequ ento D etecein g soft e rrors in combinarional a nd sequentia l logic is criti cai for avoiding erro rs in the c ircuir applicarion. Howeve r, t his eas k is co mplex becau se the intern a i ci rcu ir signals a re decrcasing to che same order of magni tud e as the transienr currenrs,generated by cha rgedpartide strikes.Researchers have proposed a bu ilr-in currem senso r (BIC S) connected to t he powe r lines for moniroring on-chip current variati ons provoked by pcrmanent faules, such as stu ckar fallles, a nd by soft erro rs in memoryelements.-4,5 However, to rh e besr of our knowledge. no one has yer proposed a BI CSbased method for derecring SETs in combinafional lo gic, a nd (his iss ue is gain ing importance in new rechn ologies. We propose an approach for using BI CS to derect transiem
Rock powders are low-cost potential sources of most of the nutrients required by higher plants for growth and development. However, slow dissolution rates of minerals represent an obstacle to the widespread use of rock powders in agriculture. Rhizosphere processes and biological weathering may further enhance mineral dissolution since the interaction between minerals, plants, and bacteria results in the release of macro- and micronutrients into the soil solution. Plants are important agents in this process acting directly in the mineral dissolution or sustaining a wide diversity of weathering microorganisms in the root environment. Meanwhile, root microorganisms promote mineral dissolution by producing complexing ligands (siderophores and organic acids), affecting the pH (via organic or inorganic acid production), or performing redox reactions. Besides that, a wide variety of rhizosphere bacteria and fungi could also promote plant development directly, synergistically contributing to the weathering activity performed by plants. The inoculation of weathering bacteria in soil or plants, especially combined with the use of crushed rocks, can increase soil fertility and improve crop production. This approach is more sustainable than conventional fertilization practices, which may contribute to reducing climate change linked to agricultural activity. Besides, it could decrease the dependency of developing countries on imported fertilizers, thus improving local development.
The generation and propagation of single event transients (SET) in logic gate chains is studied and modeled. Regarding SET generation, we investigate the dependence of the generated SET pulse width on the struck node capacitance. Rising node capacitance may lead to amplified pulse width, indicating that increasing load capacitance alone is not an option for radiation hardening. SET propagation in logic chains is also studied, and it is shown that significant broadening or attenuation of the propagated transient pulse width may be observed. It is shown that the chain design (propagation delay of high to low and low to high transitions) has a major impact on broadening or attenuation of the propagated transient pulse. For the first time a suitable model for SET broadening is provided.
Microorganisms associated with organic management are essential in nutrient transformation and release for plant use. The present study aimed to isolate, identify and characterize plant growth promoting diazotrophic rhizobacteria associated with sugarcane under organic management. Rhizospheres of organic sugarcane varieties IAC 911099 and CTC4 were sampled and inoculated onto nitrogen free NFb and Burk media. The isolated microorganisms were screened in vitro concerning their ability to produce plant growth promoting factors. Eighty-one bacteria were isolated; 45.6% were positive for the nifH gene and produced at least one of the evaluated plant growth promotion factors. The production of indole-3-acetic acid was observed in 46% of the isolates, while phosphate solubilization was observed in 86.5%. No isolates were hydrogen cyanide producers, while 81% were ammonia producers, 19% produced cellulases and 2.7%, chitinases. Microorganisms belonging to the Burkholderia genus were able to inhibit Fusarium moniliforme growth in vitro. Plant growth promoting microorganisms associated with organic sugarcane, especially belonging to Burkholderia, Sphingobium, Rhizobium and Enterobacter genera, can be environmentally friendly alternatives to improve sugarcane production.An Acad Bras Cienc (2018) 90 (4)
3814ARIANA A. RODRIGUES et al.
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