Browsing by Author "HAJEK, ER"

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    GROWING SEASONS IN CHILE - OBSERVATION AND PREDICTION
    (1979) HAJEK, ER; GUTIERREZ, JR
    Temperature data for 42 Chilean locations were analyzed and heat sums calculated (for base 5.degree. and 10.degree. C). The length, starting and ending dates of the growing seasons [for plants] were obtained. Temperature values normally found in Chilean climatological records, i.e., monthly and annual means, were related with temperature accumulations. In Chile it is possible to predict the accumulation of temperature from the annual mean temperature (r [correlation coefficient] = 0.995 P < 0.001, for base 5.degree. C and r = 0.984, P < 0.001, for base 10.degree. C) or from the mean monthly temperature of Jan. In this latter case, a good adjustment with an exponential curve is found (r = 0.76, P < 0.001, base 5.degree. C; r = 0.78, P < 0.001, base 10.degree. C). For Chile, temperature courses along the year were approximated by using a harmonic analysis. No significant differences were observed between predicted and observed values. By integrating the equations as a function of time, the accumulation of temperature and the length of growing seasons for different threshold temperatures can be determined. A significant relationship was found between these variables and the latitude, and gradients were obtained. Differences exist between littoral and continental stations in the extension of growing seasons and the accumulation of temperatures.
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    SEASONALITY OF CONCEPTION IN HUMAN-POPULATIONS IN CHILE
    (1981) HAJEK, ER; GUTIERREZ, JR; ESPINOSA, G
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    SEASONALITY OF MORTALITY IN HUMAN-POPULATIONS OF CHILE AS RELATED TO A CLIMATIC GRADIENT
    (1984) HAJEK, ER; GUTIERREZ, JR; ESPINOSA, GA
    Mortality of human populations in Chile was studied from a latitudinal and seasonal perspective, and related to climate and main diseases. Approximately 3,000,000 deaths were analyzed. Seasonality considered along a latitudinal and climatic gradient is almost absent in the northern portion of the country; in the central part peaks are evident in summer, at latitudes of 40.degree. S in winter and at 45.degree. S in winter and spring. Seasonality along the years of analysis shows a different behavior for the different zones of the country and no unique pattern is evident. A clear relationship between the air enthalpy and seasonality of mortality is detected. Circulatory diseases appear as the most important causes of deaths, exception made of latitude 40 where respiratory diseases are the significant causes of deaths. Age groups below 1 and above 65 yr are mostly affected.
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    TEMPERATURE EFFECT ON AUTOCHORY IN COLLIGUAYA-ODORIFERA (EUPHORBIACEAE)
    (1980) GILIBERTO, J; GUTIERREZ, JR; HAJEK, ER