The distribution of individual heterozygosity in natural populations

Estimation of the distribution of the level of individual heterozygosity within natural populations is explored with both Monte-Carlo simulation studies and data from natural populations. Simulations indicate that heterozygosities estimated from as few as a dozen randomly chosen loci may, to some degree, reflect (r = 0.35) heterozygosity determined by 100 independent loci. The shape of the expected distribution of heterozygosity is heavily dependent upon levels of heterozygosity at the loci. Complete genetic data for 12 loci from 997 Fundulus heteroclitus are used to describe the distributions of heterozygosity for different localities, for age classes and for sexes. The distributions deviate from normality. Distributions from different localities are not different, but the distributions are heterogeneous among age classes at one of two localities and are heterogeneous between the sexes.     

Distribution-free regression analysis of grouped survival data

Methods based on regression models for logarithmic hazard functions, Cox models, are given for analysis of grouped and censored survival data. By making an approximation it is possible to obtain explicitly a maximum likelihood function involving only the regression parameters. This likelihood function is a convenient analog to Cox's partial likelihood for ungrouped data. The method is applied to data from a toxicological experiment.     

Cytosolic location of an endo-N-acetyl-beta-D-glucosaminidase activity in rat liver and kidney.

Endo-N-acetyl-beta-D-glucosaminidase activity towards an oligomannosidic type glycoamino acid substrate was found in the soluble fraction of rat liver and kidney. No evidence for a lysosomal form of the activity was found.     

MA 160 and EB 33 cell lines: HeLa cell contaminants,hybrids or prostatic epithelial cells?

Summary Studies of acid phosphates produced by cell lines MA 160 and EB 33 demonstrated immunochemically their prostatic origin. MA 160 and EB 33, rather than being HeLa contaminants, may be hybrids of prostatic epithelial and HeLa cells or true prostatic cell lines with chromosomal changes common to all long-term cultivated cell lines. This research was supported by NIH (Cancer) Research Grants Nos. 18748 and 16426; and Detroit General Hospital Research Corporation.     

Measurement of adriamycin (doxorubicin) and its metabolites in human plasma using reversed-phase high-performance liquid chromatography and fluorescence detection

We describe a method for measuring adriamycin and its major metabolite, adriamycinol, in plasma, using reversed-phase high-performance liquid chromatography and fluorescence detection. The lower limit of detection is approximately 1 ng/ml for both compounds; within-day coefficients of variation are 3.6% and 4.4% for adriamycin and adriamycinol, respectively. A slight modification of this procedure also allows measurement of aglycone metabolites.     

A Cannibal in the National Museum: The Early Career of Franz Boas in America

Franz Boas spent several weeks at Fort Rupert, British Columbia, at the end of 1894, when he saw the Kwakiutl hamatsa ritual in situ for the first time. Soon after his return east Boas posed for a series of photographs in the U.S. National Museum for a diorama of the hamatsa dance. These photographs, now published for the first time, are a sharp reminder of Boas' constant (and sometimes forced) collaboration with the limited number of anthropological institutions in America at the end of the century, and of his personal difficulties in establishing himself professionally in America.     

Persistence and Biodegradation of Spilled Residual Fuel on an Estuarine Beach

The enrichment of hydrocarbon-degrading bacteria and the persistence of petroleum hydrocarbons on an estuarine beach after a spill of residual fuel oil on 11 April 1973 in Upper Narragansett Bay, R.I. was investigated. A rapid enrichment occurred during days 4 to 16 after the oil spill and a significant population of hydrocarbon-degrading bacteria was maintained in the beach sand for at least a year. The concentration of petroleum hydrocarbons in the mid-tide area declined rapidly during the bacterial enrichment period, remained fairly constant throughout the summer, and then declined to a low concentration after 1 year. An increased concentration of branched and cyclic aliphatic hydrocarbons in the low-tide sediment 128 days after the spill suggested a migration of hydrocarbons during the summer. Hydrocarbon biodegradation was apparent during the winter months at a rate of less than 1 mug of hydrocarbon per g of dry sediment per day.     

Comparative adaptations of Aphanizomenon and Anabaena for nitrogen fixation under weak irradiance

1. In situ measurements of nitrogen fixation rates for Aphanizomenon in fertile Colorado lakes with low inorganic nitrogen concentrations demonstrated high efficiency of nitrogen fixation at low irradiance. 2. For study populations, rates of N₂ fixation in darkness and with alternating exposure to light and darkness were a higher percentage of light‐saturated rates for Aphanizomenon than for Anabaena, suggesting storage of reduced metabolites at high irradiance that are used subsequently by Aphanizomenon when cells are forced by mixing into zones of low irradiance. Also, saturation of N₂ fixation occurred over a lower range of irradiance for Aphanizomenon than for Anabaena. 3. High efficiency of N₂ fixation in Aphanizomenon at low or fluctuating irradiance is complementary to its previously demonstrated high efficiency of photosynthesis at low irradiance. Nitrogen fixation rate was also strongly related to DIN concentration; fixation was highest at low DIN (maximum < 5 μg L^?1) but was also most vulnerable to photoinhibition under such conditions. 4. The fixation capabilities of Aphanizomenon under weak or varying irradiance could explain its commonly observed domination over Anabaena when transparency is low and available nitrogen is scarce.     

Effect of recent changes in atomic bomb survivor dosimetry on cancer mortality risk estimates

The Radiation Effects Research Foundation has recently implemented a new dosimetry system, DS02, to replace the previous system, DS86. This paper assesses the effect of the change on risk estimates for radiation-related solid cancer and leukemia mortality. The changes in dose estimates were smaller than many had anticipated, with the primary systematic change being an increase of about 10% in gamma-ray estimates for both cities. In particular, an anticipated large increase of the neutron component in Hiroshima for low-dose survivors did not materialize. However, DS02 improves on DS86 in many details, including the specifics of the radiation released by the bombs and the effects of shielding by structures and terrain. The data used here extend the last reported follow-up for solid cancers by 3 years, with a total of 10,085 deaths, and extends the follow-up for leukemia by 10 years, with a total of 296 deaths. For both solid cancer and leukemia, estimated age-time patterns and sex difference are virtually unchanged by the dosimetry revision. The estimates of solid-cancer radiation risk per sievert and the curvilinear dose response for leukemia are both decreased by about 8% by the dosimetry revision, due to the increase in the gamma-ray dose estimates. The apparent shape of the dose response is virtually unchanged by the dosimetry revision, but for solid cancers, the additional 3 years of follow-up has some effect. In particular, there is for the first time a statistically significant upward curvature for solid cancer on the restricted dose range 0-2 Sv. However, the low-dose slope of a linear-quadratic fit to that dose range should probably not be relied on for risk estimation, since that is substantially smaller than the linear slopes on ranges 0-1 Sv, 0-0.5 Sv, and 0- 0.25 Sv. Although it was anticipated that the new dosimetry system might reduce some apparent dose overestimates for Nagasaki factory workers, this did not materialize, and factory workers have significantly lower risk estimates. Whether or not one makes allowance for this, there is no statistically significant city difference in the estimated cancer risk.