With practical importance to agriculture, one of the most interesting antagonisms in ion uptake by plants is that of potassium and magnesium. Magnesium deficiency is a rather old problem, which has ...already been studied over a long period of time (HUDIG and MEYER 1918, VAN ITALLIE 1937, SCHUFFELEN 1940, SMIT AND MULDER 1942). It has frequently been found to be associated with a disturbed balance between potassium and magnesium.The classical approach toward studies on ion relationships made use of plants grown in cultural media over a relatively long period of time. More recent studies employ short-term cultures in which the selective accumulation and excretion mechanisms of ions are examined in excised roots, other plant parts, or individual cells. Both techniques will be used in the present study.Inter-ionic influences on uptake under the "root-uptake" concept may be viewed within the framework of the commonly proposed carrier system for metabolic uptake. However, it must be stipulated in advance that not all ionic relationships found in carrier studies can be interpreted to be applicable to foliar tissues.For instance, Ca and Mg show an inverse relationship in the leaf in many plants, but are reported to pass over different sites (EPSTEIN and LEGGETT 1954 and MOORE et ah 1961). This can be said also for Mg and K uptake. A strong reciprocal relationship between K and Mg in leaves has been found in many plants, but in long-term experiments by SCHARRER and MENGEL (1958), K was found not to compete with Mg absorption in the roots of intact corn and sunflower plants.ZIMMERMANN (1947), JACOB (1955), SCHILLING (1957) and BAUMEISTER (1958) have presented reviews of studies on magnesium-potassium interactions. These reviews will be examined here inasfar as they touch upon the uptake of Mg by plants as influenced by the ionic composition of the cultural medium.The present review will deal with the absorption of Mg as influenced by cations and anions in general, and by certain ionic groups or individual ions. Special attention will be given to the effect of such relationships on crop yields and on the occurrence of Mg deficiency symptoms. Furthermore, absorption mechanisms, synergistic effects, and the protection of the integrity of selective ion transport systems, as studied in short-term experiments, will be reviewed.
Sixty nine open negative cavities (unilocular 29 and multilocular 40) in 57 pulmonary tuberculosis patients were radiologically followed up for 2-10 years after negative conversion of sputum. All ...cavities were tomographically classified according to the Iwasaki-Iwai's classification. (Fig. 1). The distribution of type of cavities was investigated annually after negative conversion of sputum. At 6 months after negative conversion of sputum, the proportion of A, B and C was small, that of D, E and H was 42%, and that of F and G was about 50%. At 1 year, the proportion of A, B and C became higher (about 30%), and that of F and G became lower (about 29%). The tendency continued until 4 years after negative conversion of sputum, and at 4 years, the proportion of A, B and C reached to 43% and that of F and G reduced to 10%. (Fig. 2a). Generally speaking, the wall of an unilocular cavity became thinner more rapidly, in about 2 years, than that of a multilocular cavity, in about 4 years. (Fig. 2b). No definite difference was recognized between the primary treatment group and the re-treatment group in the yearly changes of the cavitary wall. (Fig. 2c). The changes of cavity after reaching to each A, B, C, D, E, F, G or H were annually investigated. (Table 4 and 5). Most of cavity A and C remained unchanged. Cavity B and D showed further slight changes. No bacteriological relapse was observed among types A, B, C and D. Most of cavities E, F, G and H showed further changes, and the changes was most marked among H type and many showed diminution of cav itary size. A few relapse were observed among types E, F, G and H. In general, only a few cavities showed complete disappearance, inspissation or consolidation. Some of cavities of each type diminished in size, and a very few showed dilatation in, size. A few cavities were contaminated, by fungus infection. From the above results, it is recommended that effective chemotherapy should be continued in open negative cavity for at least 2 years in unilocular cavity and at least 4 years in multilocular cavity, so that the cavity wall become stable and preferably, as thin as in cavities of A and C. Moreover, caution should be paid for the contamination of fungus infection.
Stress relaxation tests were carried out for a P/M Al-8 mass%Fe alloy using a lever type creep machine at temperatures from 573 to 673 K. The way to estimate the strain rate just after the start of ...stress relaxation, \dotεr0, was discussed. The values of \dotεr0 were compared with the strain rate just before the relaxation test(steady-state creep rate), \dotεs, and the work hardening rate, h, and the recovery rate, r, were determined. The relation between the strain rate, \dotεr, and the actual stress of the specimen, (σ−σr), during the stress relaxation test, was almostly linear in a log-log plot except the early stage after the start of stress relaxation. The \dotεr0 was estimated by extrapolating the linear relation to the initial creep stress. The \dotεr0 was usually smaller than the \dotεs, which showed that the contribution of the effective stress to high temperature deformation could be neglected in the present alloy. The h did not depend on temperature and slightly or scarcely decreased with the increase in stress, while it tended to decrease rapidly in the high stress range above a critical stress, that is the Orowan stress. The r, on the other hand, largely depended on stress and temperature, and the activation energy for it was close to that determined from the temperature dependence of the steady state creep rate, \dotεs. Relation between \dotεr and actual stress (σ−σr) during the relaxation tests in the low stress region below the critical stress was very close to one between steady-state creep rate \dotεs and creep stress σc obtained by creep tests at each temperature. It is thought that the internal structure during the stress relaxation is close to one in the steady state creep deformation.
This study examines the spread of international terrorism from 1968 to 1974. Using Poisson and negative binomial probability models, a diffusion of international terrorism was found in the first ...segment of the time period (1968-1971) and contagion as a direct modeling process in the second (1973-1974). Accordingly, the theory of hierarchies in which the diplomatic status of a country predicts its degree of imitability was found to operate among Latin American countries during the second portion of the overall period, but not during the first. An inverse hierarchy is suggested as an explanation for the contagion of violence from Latin America and other third world countries to Western Europe. Autocorrelation functions were used to assess which forms of terrorism were most contagious in which regions.
A monitorização mensal de alanina aminotransferase (ALT) sérica de pacientes em hemodiálise e os testes sorológicos para exclusões de infecções por vírus da hepatite A (HAV), vírus da hepatite B ...(HBV), citomegalovirus (CMV) e vírus Epstein-Barr (EBV), permitiu-nos identificar 11 casos de hepatites não-A, não-B em 111 indivíduos avaliados durante o período de 12 meses e acompanhados por 2 anos. Foram observados 3 padrões de atividade de ALT: elevação em pico monofásico em 2, bifásico ou polifásico em 6 e em platô em 3 pacientes. Individíduos com padrão monofásico exibiram os níveis mais elevados de ALT. Cinco pacientes apresentaram normalização bioquímica persistente 4,8 meses em média após o início da elevação aguda e seis evoluíram com ascensão crônica de ALT durante o período de estudo. A hepatite não-A, não-B foi, predominantemente, assintomática e anictérica, sempre antecedida por transfusões sangüíneas e com maior incidência nos seis primeiros meses de terapia dialítica dos pacientes.
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