Variação de matéria seca e de nutrientes nas folhas e nos frutos, produção de ácido ascórbico e suco, em seis cultivares de citros, durante um ciclo

De uma plantação de citros, com os cultivares T. Cravo (Citrus reticulata Blanco), L.Hamlin (Citrus sinensis (L.) Osbeck), T. Murcott (Citrus reticulata Blanco x Citrus sinensis (L.) Osbeck), L. Natal (Citrus sinensis (L.) Osbeck, L. Valencia (Citrus sinensis (L.) Osbeck) e L. Pera (Citrus sinensis (L.) Osbeck), situada na "Fazenda Sete Lagoas", no município de Mogi-Guaçu (22° 22% 46° 56'W.Gr.), em Latossolo Vermelho amarelo, fase arenosa, foram coletados frutos 30 dias após florescimento, até a idade da coleta comercial. No material coletado, foram determinadas a variação da matéria seca, a concentração dos macro e micronutrientes nas folhas adjacentes ao fruto, a extração de macro e micronutríentes pelos frutos, a produção de suco (ml) por fruto e a concentração de ácido ascórbico (mg/100 ml de suco). Concluiu-se que: 1. O aumento da matéria seca, intensifica-se a partir do segundo mês apos o florescimento; 2. Com exceção da T. Cravo, ocorre uma diminuição na produção de matéria seca no final do ciclo; 3. A concentração dos macro e micronutrientes nas folhas apresenta oscilações durante o desenvolvimento do fruto; 4. A ordem decrescente de extração de nutrientes é: K, N, Ca, Mg, P = S, Fe, B, Zn, Mn, Cu; 5. A capacidade de exportação de nutrientes pelos cultivares é, em ordem decrescente: L. Pera, L. Hamlin = T. Cravo, T. Murcott, L. Valencia, L. Natal; 6. A quantidade de suco produzido por fruto, oscila entre 43 a 95 ml; 7. A concentração de ácido ascórbico (mg/100 ml de suco), varia entre 30 a 95

Detectable clonal mosaicism and its relationship to aging and cancer

In an analysis of 31,717 cancer cases and 26,136 cancer-free controls from 13 genome-wide association studies, we observed large chromosomal abnormalities in a subset of clones in DNA obtained from blood or buccal samples. We observed mosaic abnormalities, either aneuploidy or copy-neutral loss of heterozygosity, of >2 Mb in size in autosomes of 517 individuals (0.89%), with abnormal cell proportions of between 7% and 95%. In cancer-free individuals, frequency increased with age, from 0.23% under 50 years to 1.91% between 75 and 79 years (P = 4.8 × 10(-8)). Mosaic abnormalities were more frequent in individuals with solid tumors (0.97% versus 0.74% in cancer-free individuals; odds ratio (OR) = 1.25; P = 0.016), with stronger association with cases who had DNA collected before diagnosis or treatment (OR = 1.45; P = 0.0005). Detectable mosaicism was also more common in individuals for whom DNA was collected at least 1 year before diagnosis with leukemia compared to cancer-free individuals (OR = 35.4; P = 3.8 × 10(-11)). These findings underscore the time-dependent nature of somatic events in the etiology of cancer and potentially other late-onset diseases

Use of benefit-cost analysis in establishing Federal radiation protection standards: a review

This paper complements other work which has evaluated the cost impacts of radiation standards on the nuclear industry. It focuses on the approaches to valuation of the health and safety benefits of radiation standards and the actual and appropriate processes of benefit-cost comparison. A brief historical review of the rationale(s) for the levels of radiation standards prior to 1970 is given. The Nuclear Regulatory Commission (NRC) established numerical design objectives for light water reactors (LWRs). The process of establishing these numerical design criteria below the radiation protection standards set in 10 CFR 20 is reviewed. EPA's 40 CFR 190 environmental standards for the uranium fuel cycle have lower values than NRC's radiation protection standards in 10 CFR 20. The task of allocating EPA's 40 CFR 190 standards to the various portions of the fuel cycle was left to the implementing agency, NRC. So whether or not EPA's standards for the uranium fuel cycle are more stringent for LWRs than NRC's numerical design objectives depends on how EPA's standards are implemented by NRC. In setting the numerical levels in Appendix I to 10 CFR 50 and 40 CFR 190 NRC and EPA, respectively, focused on the costs of compliance with various levels of radiation control. A major portion of the paper is devoted to a review and critique of the available methods for valuing health and safety benefits. All current approaches try to estimate a constant value of life and use this to vaue the expected number of lives saved. This paper argues that it is more appropriate to seek a value of a reduction in risks to health and life that varies with the extent of these risks. Additional research to do this is recommended. (DC