903 research outputs found

    Cortical pain responses in human infants

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    Despite the recent increase in our understanding of the development of pain processing, it is still not known whether premature infants are capable of processing pain at a cortical level. In this study, changes in cerebral oxygenation over the somatosensory cortex were measured in response to noxious stimulation using real-time near-infrared spectroscopy in 18 infants aged between 25 and 45 weeks postmenstrual age. The noxious stimuli were heel lances performed for routine blood sampling; no blood tests were performed solely for the purpose of the study. Noxious stimulation produced a clear cortical response, measured as an increase in total hemoglobin concentration [HbT] in the contralateral somatosensory cortex, from 25 weeks (mean Delta[HbT] = 7.74 mu mol/L; SE, 1.10). Cortical responses were significantly greater in awake compared with sleeping infants, with a mean difference of 6.63 mu mol/L [95% confidence interval (CI) limits: 2.35, 10.91 mu mol/L; mean age, 35.2 weeks]. In awake infants, the response in the contralateral somatosensory cortex increased with age ( regression coefficient, 0.698 mu mol/L/week; 95% CI limits: 0.132, 1.265 mu mol/L/week) and the latency decreased with age (regression coefficient, -0.9861 mu mol/L/week; 95% CI limits: -1.5361, -0.4361 mu mol/L/week; age range, 25-38 weeks). The response was modality specific because no response was detected after non-noxious stimulation of the heel, even when accompanied by reflex withdrawal of the foot. We conclude that noxious information is transmitted to the preterm infant cortex from 25 weeks, highlighting the potential for both higher-level pain processing and pain-induced plasticity in the human brain from a very early age

    Transportation Systems with Autonomous Vehicles: Models and algorithms for equilibrium assignment

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    Abstract Technologies for connected, automated or autonomous vehicles (AVs) are fast developing, so that they seem ready for substituting in the near future privately owned non-autonomous traditional vehicles (TVs) and further supporting the spread of shared vehicles both for person and good transportation. On the other hand, it may easily be anticipated that the time needed to turn the existing stock of TVs into AVs will last several years during which mixed traffic is expected. A change so great may be not technology-driven only, but also requires a carefully analysis of its several impact through well designed enhancements of tools already available to the transportation systems modelers and planners. Such enhanced tools may be casted in the general framework of multi-user class assignment to transportation networks, concerning: (i) transportation network analysis, through level-of-service models distinguishing between non-autonomous vs. autonomous vehicles, presumably sharing same infrastructure; (ii) travel demand analysis, through behavioral choice modeling paradigms, including choice between AVs vs. TVs, owned vs. shared, as well as route choice behavior; (iii) steady-state equilibrium assignment. This paper describes models and algorithms to deal with steady-state equilibrium assignment; they are used to show to which extent existing methods can still be applied as well as which issues remain still open and worth of further research efforts

    Contact resistance and overlapping capacitance in flexible sub-micron long oxide thin-film transistors for above 100 MHz operation

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    In recent years new forms of electronic devices such as electronic papers, flexible displays, epidermal sensors, and smart textiles have become reality. Thin-film transistors (TFTs) are the basic blocks of the circuits used in such devices and need to operate above 100 MHz to efficiently treat signals in RF systems and address pixels in high resolution displays. Beyond the choice of the semiconductor, i.e., silicon, graphene, organics, or amorphous oxides, the junctionless nature of TFTs and its geometry imply some limitations which become evident and important in devices with scaled channel length. Furthermore, the mechanical instability of flexible substrates limits the feature size of flexible TFTs. Contact resistance and overlapping capacitance are two parasitic effects which limit the transit frequency of transistors. They are often considered independent, while a deeper analysis of TFTs geometry imposes to handle them together; in fact, they both depend on the overlapping length (LOV) between source/drain and the gate contacts. Here, we conduct a quantitative analysis based on a large number of flexible ultra-scaled IGZO TFTs. Devices with three different values of overlap length and channel length down to 0.5 Όm are fabricated to experimentally investigate the scaling behavior of the transit frequency. Contact resistance and overlapping capacitance depend in opposite ways on LOV. These findings establish routes for the optimization of the dimension of source/drain contact pads and suggest design guidelines to achieve megahertz operation in flexible IGZO TFTs and circuits

    Recomendação de adubação de aveia em Latossolo vermelho-amarelo em dois sistemas de plantio.

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    Upland rice under no-tillage preceded by crops for soil cover and nitrogen fertilization.

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    The grain yield of upland rice under no-tillage has been unsatisfactory and one reason could be the nitrate/ammonium balance in the soil. Cover crops and nitrogen fertilization can be used to change the nitrate/ammonium relation in the soil and improve conditions for the development of upland rice in the no-tillage (NT) system. The aim was to study the effect of cover crops and nitrogen sources on grain yield of upland rice under no tillage. The study was carried out on the Fazenda Experimental Lageado, in Botucatu, State of SĂŁo Paulo, Brazil, in an Oxisol area under no-tillage for six years. The experiment was arranged in a randomized block split-plot design with four replications. The plots consisted of six cover crop species (Brachiaria brizantha, B. decumbens, B. humidicola, B. ruziziensis, Pennisetum americanum, and Crotalaria spectabilis) and the split-plots of seven forms of N fertilizer management. Millet is the best cover crop to precede upland rice under NT. The best form of N application, as nitrate, is in split rates or total rate at topdressing or an ammonium source with or without a nitrification inhibitor, in split doses. When the cover crops C. spectabilis, B. brizantha, B. decumbens, B. humidicola, and B. ruziziensis preceded rice, they induced the highest grain yield when rice was fertilized with N as ammonium sulfate source + nitrification inhibitor in split rates or total dose at topdressing

    Teor de nitrogĂȘnio inorgĂąnico no solo em função de plantas de cobertura, fontes de nitrogĂȘnio e inibidor de nitrificação.

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    A utilização de plantas de cobertura pode alterar a relação NO3 -:NH4 + no solo, proporcionando maiores quantidades de NH4 + e podendo viabilizar o desenvolvimento de culturas que absorvem mais e preferem esta forma de nitrogĂȘnio (N), como o arroz. Objetivou-se avaliar a influĂȘncia da interação de plantas de cobertura e fontes de N, com e sem inibidor de nitrificação (dicianodiamida), em sistema plantio direto (SPD). O experimento foi realizado em 2009/2010, em Botucatu (SP), em Latossolo Vermelho distrofĂ©rrico cultivado por seis anos no SPD. O delineamento experimental foi em blocos casualizados, em esquema de parcela subdividida, com quatro repetiçÔes. As parcelas foram constituĂ­das por seis espĂ©cies de plantas de cobertura do solo (Urochloa brizantha, U. decumbens, U. humidicola, U. ruziziensis, Pennisetum americanum e Crotalaria spectabilis) e as subparcelas por sete formas de fertilização nitrogenada, aos 0 e 30 dias apĂłs a emergĂȘncia (DAE) do arroz [1 - controle, sem aplicação de nitrogĂȘnio; 2 - nitrato de cĂĄlcio (40 + 40 kg ha-1); 3 - nitrato de cĂĄlcio (0 + 80 kg ha-1); 4 - sulfato de amĂŽnio (40 + 40 kg ha-1); 5 - sulfato de amĂŽnio (0 + 80 kg ha-1); 6 - sulfato de amĂŽnio + dicianodiamida (40 + 40 kg ha-1); e 7 - sulfato de amĂŽnio + dicianodiamida (0 + 80 kg ha-1)]. O uso do inibidor de nitrificação e o cultivo de C. spectabilis proporcionaram maiores teores de amĂŽnio no solo. A aplicação da fonte amoniacal sem inibidor em dose total aos 30 DAE e com inibidor tanto parcelada quanto em dose total proporcionaram os maiores teores de nitrato no solo

    Improvement of contact resistance in flexible a-IGZO thin-film transistors by CF4/O2 plasma treatment

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    In this work, we analyze the effect of CF4/O2 plasma treatment on the contact interface between the amorphous Indium-Gallium-Zinc-Oxide (a-IGZO) semiconductor and Titanium-Gold electrodes. First, the influence of CF4/O2 plasma treatment is evaluated using transmission line structures and compared to pure O2 and CF4 plasma, resulting in a reduction of the contact resistance RC by a factor of 24.2 compared to untreated interfaces. Subsequently, the CF4/O2 plasma treatment is integrated in the a-IGZO thin-film transistor (TFT) fabrication process flow. We achieve a reduction of the gate bias dependent RC by a factor up to 13.4, which results in an increased current drive capability. Combined with an associated channel length reduction, the effective linear field-effect mobility is increased by up to 74.6% for the CF4/O2 plasma treated TFTs compared to untreated reference devices

    Soil Nitrate Level Variation under Intensive Nitrogen Fertilized Coastcross Pasture

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    Nitrate levels in soil profile after the first N application on coastcross pasture, grown on a dark red latosol (Hapludox), in SĂŁo Carlos, SP, Brazil, under tropical altitude climate, were measured at 7-day intervals, to monitor possible losses in depth. Soil nitrate rates varied with high rates of N-ammonium nitrate (200 kg ha-1 per cutting) in surface layers. Danger of environmental impact was low in the studied conditions
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