Experimental assessment of a pebble reflector and pebble flow in a small scale recirculating pebble bed.

The erosion behaviour of a pebble reflector was examined using small scale, three-dimensional, pebble-bed models and the split-bed technique. An exponential-type change in the reflector-fuel interface angle was indicated. The levelled value was about 13° after recirculation of 30 - 40 bed inventories. Data on downflow and upflow air tests with small-scale, recirculating pebble beds are also presented. These data indicated a variation in pebble discharge ratio of some 20 per cent relative to the non-airflow case

Survival of adult AIDS patients in a reference hospital of a metropolitan area in Brazil Sobrevivência de pacientes adultos com Aids em hospital de referência no Nordeste brasileiro

OBJECTIVE: To evaluate the influence of sociodemographic, clinical, and epidemiological factors in AIDS patients survival in a reference hospital. METHODS: A sample of 502 adult AIDS patients out of 1,494 AIDS cases registered in a hospital in Fortaleza, Brazil, was investigated between 1986 and 1998. Sixteen cases were excluded due to death at the moment of the AIDS diagnosis and 486 were analyzed in the study. Socioeconomic and clinical epidemiological were the variables studied. Statistical analysis was conducted using the Kaplan-Meier survival analysis and the Cox proportional hazards model. RESULTS: Three hundred and sixty two out of the 486 patients studied took at least one antiretroviral drug and their survival was ten times longer than those who did not take any drug (746 and 79 days, respectively, p <0.001). Patients who took two nucleoside reverse transcriptase inhibitors (NRTI) plus protease inhibitor were found to have higher survival rates (p <0.001). The risk of dying in the first year was significantly lower for patients who took NRTI and a protease inhibitor compared to those who took only NRTI. In addition, this risk was much lower from the second year on (0.10; 95%CI: 0.42-0.23). The risk of dying in the first year was significantly higher for less educated patients (15.58; 95%CI: 6.64-36.58) and those who had two or more systemic diseases (3.03; 95%CI: 1.74-5.25). After the first year post-diagnosis, there was no risk difference for these factors. CONCLUSIONS: Higher education revealed to exert a significant influence in the first-year survival. Antiretroviral drugs had a greater impact in the survival from the second year on. A more aggressive antiretroviral therapy started earlier could benefit those patients.<br>OBJETIVO: Avaliar, em um hospital de referência, a influência de fatores sociodemográficos e clínico-epidemiológicos na sobrevivência de pacientes com Aids. MÉTODOS:Foi estudada uma amostra de 486 adultos com Aids atendidos em hospital de referência no Ceará, entre 1986 e 1998. Foram avaliadas as variáveis socioeconômicas e clínico-epidemiológicas. A análise foi realizada pelo método Kaplan-Meier e por regressão de Cox. RESULTADOS: Dos 486 pacientes estudados, 362 utilizaram pelo menos uma droga anti-retroviral e tiveram sobrevida dez vezes maior que os que não a utilizaram (746 e 79 dias, respectivamente; p<0,001). O risco de morrer, no primeiro ano, foi significativamente menor (0,25; IC95%: 0,12-0,50) para os que fizeram uso de dois inibidores de transcriptase reversa ou HAART e menor a partir do segundo ano (0,10; IC95%:0,42-0,23) em relação aos que não os usaram. Indivíduos sem nível universitário (15,58; IC95%:6,64-36,58) e que apresentaram duas ou mais doenças sistêmicas (3,03; IC95%:1,74-5,25) tiveram risco significativamente maior de morrer no primeiro ano. Após o primeiro ano, não se observou diferença. CONCLUSÃO: O melhor nível socioeconômico, medido indiretamente pela escolaridade, demonstrou grande influência na sobrevivência no primeiro ano. As drogas anti-retrovirais tiveram mais impacto na sobrevivência a partir do segundo ano, assim como igualaram o risco de morrer de pacientes com duas ou mais doenças sistêmicas àqueles que não tiveram nenhuma no mesmo período. Concluiu-se que uma introdução mais precoce e mais agressiva dos anti-retrovirais poderia beneficiar os pacientes