1,293 research outputs found
Evolution of the Antarctic polar vortex in spring: Response of a GCM to a prescribed Antarctic ozone hole
The possible effect of the Antartic ozone hole on the evolution of the polar vortex during late winter and spring using a general circulation model (GCM) is examined. The GCM is a version of the NCAR Community Climate Model whose domain extends from the surface to the mesosphere and is similar to that described on Boville and Randel (1986). Ozone is not a predicted variable in the model. A zonally averaged ozone distribution is specified as a function of latitude, pressure and month for the radiation parameterization. Rather that explicitly address reasons for the formation of the ozone hole, researchers postulate its existence and ask what effect it has on the subsequent evolution of the vortex. The evolution of the model when an ozone hole is imposed is then discussed
Influencia do alumínio de um podzólico vermelho-amarelo do Acre sobre o crescimento das plantas.
Efeito de doses e modos de aplicação de uréia na produção de feijão
The effect of rate and method of urea application on the yield of common beans (Phaseolus vulgaris L., cv. IPA-1) was evaluated on a Red-Yellow Latosol (Psamentic Haplortox) of Arapiraca and on a Solodic Planosol (Ustalf) of Igaci, both sandy-clay-loams located in the State of Alagoas, Brazil. Rates of 30,60 and 90 kg N/ha were applied placing the urea totally in the furrow at planting time; totally sidedressed twenty days after planting, mixed or not with the soil; or 1/3 of the amount in the furrow at planting plus 2/3 sidedressed twenty days after planting, mixed or not with the soil. Bean yield responses to nitrogen followed quadratic equations. In the Red-Yellow Latosol response to nitrogen occurred up to the rate of 66 kg N/ha, while in the Solodic Planosol the yield increased up to the highest applied rate of 90 kg N/ha. The relative yield increase for each site was 22% and 16%, respectively. Sidedressed application of the total amount of urea resulted in the lowest yields, whereas split application and furrow fertilization were the best and equally effective methods. No significant yield increase was observed by mixing the urea with the soil.O efeito de doses e modos de aplicação de uréia na produção de feijão (Phaseolus vulgaris L., cv. IPA-1) foi avaliado em um latossolo vermelho-amarelo de Arapiraca (AL) e em um planossolo solódico de Igaci (AL), ambos franco-argilo-arenosos. Doses de 30, 60 e 90 kg/ha de N foram aplicadas totalmente no sulco de plantio, totalmente em cobertura aos vinte dias após o plantio com ou sem incorporação, e 1/3 no sulco de plantio mais 2/3 em cobertura com ou sem incorporação. A produção de feijão aumentou com a dose de nitrogênio segundo equações quadrátricas. No latossolo vermelho-amarelo, o feijão respondeu à aplicação de nitrogênio até a dose de 66 kg/ha de N, enquanto no planossolo solódico a produção aumentou até a dose maior de 90 kg/ha de N. Os aumentos respectivos de produção em cada local foram de 22% e 16%. A aplicação de uréia de uma só vez em cobertura conferiu as menores produções, enquanto o fracionamento da dose em duas aplicações, bem como a adição única no plantio, foram os melhores métodos e igualmente efetivos. Não houve aumento significativo da produção de feijão com a incorporação da uréia no solo
O alumínio trocável de um solo podzólico vermelho-amarelo no Acre e sua obsorção pelas plantas.
A Comparative Study of the Characteristics of High Technology Start-Up Firms
A sample of two hundred and twenty-five high technology start-up firms located nationwide provided a base for the analysis of characteristics of start-up success. The analysis provides insights into management capabilities which may be generalized to a larger population. For comparison purposes, the sample was divided into two groups: (1) those firms which have not received a venture capital infusion from a formal venture capital company and (2) those firms which have received one or more infusions of venture capital. Aspects of organizational climate, top management team approach, marketing strategy and focus, business planning and the intent to go public as a means of addressing future financing needs were examined. Hypothesis testing was accomplished through the employment of ANOVA and Chi-Square. Based upon the results of the testing of each of the hypotheses, the following conclusions are drawn: 1. Based upon those aspects examined, both the funded and unfunded firms embrace practices which strongly manifest those of an organic organization. The strong propensities toward both open communication channels and participatory decision making are indicative of the lack of formal structure present in these organizations. In addition, creativity is strongly supported, as it should be, by the notion that failure is viewed in a positive context as a necessary component of both being creative and making technological advancements. 2. The team approach to management is practiced by both funded and unfunded firms; although the venture capital funded firms have a higher quality top management team when quality is defined by aggregate primary past functional experience. The funded firm has a larger team which, in turn, brings more years of experience, a higher aggregate level of organizational responsibility, and more diversity of functional capability. This diversity provides balance in terms of complementary functional skills. Additional strength is added to the top management team of the funded firms due to a higher percentage of members whose prior experience is directly related to the functional capacity in which they now serve. Similarly, the funded firm is more likely to have management team members whose previous experience was in a firm whose core technology was the same or very similar to that of the start-up. 3. There do not appear to be significant differences between the venture capital funded and unfunded firms regarding the various marketing oriented characteristics. Both groups tend to be market driven with a solutions orientation. 4. The high technology start-up firm which has received venture capital funding is more likely to go public than the unfunded firm. 5. Business planning is practiced by the majority of all high technology start-up firms, although the funded firms do so to a greater extent. Not only do virtually all funded firms prepare business plans, but the plans themselves appear to be more extensive. Additionally; the primary purpose for which the funded firm prepares the plan is for venture capital acquisition. On the other hand, the unfunded firms perform business plan preparation to a lesser extent, but do so because of operating necessity. The results of this study have implications for the nascent entrepreneur in the high technology arena and researchers alike toward the end of providing a more complete understanding of some of the critical components essential to the success of a start-up
Economic survey of small slaughtering plants in Missouri
Report on Department of Agricultural Economics Research Project 150, 'Marketing Meat in Missouri'--P. [3].Digitized 2007 AES
Effective mass and band nonparabolicity in remote doped Si/Si0.8Ge0.2 quantum wells
The effective masses in remote doped Si/Si0.8Ge0.2/Si quantum wells having sheet densities, Ns in the range 2 × 1011–1.1 × 1012 cm – 2 have been determined from the temperature dependencies of the Shubnikov–de Haas oscillations. The values obtained increase with magnetic field and Ns. This behavior is taken as evidence for the nonparabolicity of the valence band and accounts for the discrepancies in previously reported masses. Self-consistent band structure calculations for a triangular confinement of the carriers have also been carried out and provide confirmation of the increase in mass with Ns. Theory and experiment give extrapolated Gamma point effective masses of 0.21 and 0.20 of the free-electron mass, respectively
Sorption-Enhanced Water-Gas Shift Reaction for Synthesis Gas Production from Pure CO: Investigation of Sorption Parameters and Reactor Configurations
A sorption-enhanced water-gas shift (SEWGS) system providing CO2-free synthesis gas (CO + H2) for jet fuel production from pure CO was studied. The water-gas shift (WGS) reaction was catalyzed by a commercial Cu/ZnO/Al2O3 catalyst and carried out with in-situ CO2 removal on a 20 wt% potassium-promoted hydrotalcite-derived sorbent. Catalyst activity was investigated in a fixed bed tubular reactor. Different sorbent materials and treatments were characterized by CO2 chemisorption among other analysis methods to choose a suitable sorbent. Cyclic breakthrough tests in an isothermal packed bed microchannel reactor (PBMR) were performed at significantly lower modified residence times than those reported in literature. A parameter study gave an insight into the effect of pressure, adsorption feed composition, desorption conditions, as well as reactor configuration on breakthrough delay and adsorbed amount of CO2. Special attention was paid to the steam content. The significance of water during adsorption as well as desorption confirmed the existence of different adsorption sites. Various reactor packing concepts showed that the interaction of relatively fast reaction and relatively slow adsorption kinetics plays a key role in the SEWGS process design at low residence time conditions
Nitrogen Dynamics from Decomposing Litter of \u3ci\u3ePanicum maximum\u3c/i\u3e with Different Nitrogen and Phosphorus Content in Brazilian Alfissol
The objective of this study was to measure the dynamics (immobilization and release) of N and to evaluate the effect of the initial chemical composition of four Panicum maximum cultivars grown in a Alfisol and fertilized with different levels of nitrogen (0, 80 e 160 kg ha-1 de N) and phosphorus (0 e 200 kg ha-1), on the release of the N from the litter using the litterbags technique. There was an increase in the litter initial concentration of N with time of decomposition. The Aruana and Vencedor cultivars released about 70 and 60% of N; respectively, during the decomposition of the litter from 0 (zero) to 336 days; the Tobiatã and Tanzânia cultivars released about 30 and \u3e30% of N from the concentration of the initial litter respectively. Nitrogen fertization increased the N release, up to 20% in the highest N level tested (160 kg ha-1 of N)
Treatment of invasive fungal infections in clinical practice: a multi-centre survey on customary dosing, treatment indications, efficacy and safety of voriconazole
Invasive fungal infections are frequent and often deadly complications in patients with malignant hematological diseases. Voriconazole is a third generation triazole antifungal with broad activity against most clinically relevant fungal pathogens. Clinical practice often deviates from insights gained from controlled randomized trials. We conducted a multi-centre survey to evaluate efficacy, safety, treatment indications and dosing of voriconazole outside clinical trials. Patients receiving voriconazole were documented via electronic data capturing. An analysis was conducted after submission of 100 episodes from September 2004 to November 2005. Voriconazole was administered for suspected or proven invasive fungal infection (IFI) (57%), as empirical treatment in patients with fever of unknown origin (21%) and secondary (19%) as well as primary (3%) prophylaxis of IFI. Investigators’ assessment of fungal infection often diverted from EORTC/MSG 2002 criteria. A favorable response was reported in 61.4% for suspected or proven IFI and 52.4% for empirical treatment. Mortality was 15%, 26.7% of which was attributable to IFI. Breakthrough fungal infections occurred in four (21.1%) patients with voriconazole as secondary prophylaxis. Toxicity and adverse events comprised elevated liver enzymes and visual disturbances. Although indications frequently deviated from clinical evidence and legal approval, voriconazole showed efficacy and safety, comparable to major controlled clinical trials. Data from this survey demonstrate the difficulty of putting drugs to their approved use in IFI
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