Estuarine fish communities of the eastern James-Hudson Bay coast

Synopsis Sampling in six estuaries of the east coast of James and Hudson Bays between 1973 and 1977 has revealed latitudinal differences in the composition of fish communities. Arctic and subarctic marine species are more prominent in estuaries of Hudson Bay. Fewer species are found northwards with 35 species in lower rivers and estuaries of James Bay and only 24 in those of Hudson Bay, for a total of 38 species. Climate, postglacial dispersion and restricted space are proposed as causes of the observed distribution of fishes. Send reprint request to this address     

Relative Efficiency of the Case-Control to the Cohort Design in Epidemiology

In deriving the efficiency of the stratified to the simple random sample design in survey research, the critical link between the designs is the population analysis of variance. Analogously, the efficiency of the case-control to the cohort design in epidemiologic research can be derived using Bayes' theorem as the essential connection between the designs. Prior information on the odds of the disease is also required. A numerical example using data from Fleiss' text is used to illustrate the result.     

Phosphate supplying power of rock phosphates in an oxisol

Summary The P-supplying power of triple superphosphate, three apatitic rock phospates and a calcined aluminum rock phosphate were tested by measuring the quantities of fertilizer P recovered in soybean and in four chemical extractants, after 3-day and 75-day periods of contact between soil and fertilizer.The triple superphosphate supplied the highest amounts of P, but it lost efficiency during the longer incubation period. The rock phosphates maintained their original efficiencies, probably as a result of a balance between P released from the fertilizer and P converted into non-labile forms.The following coefficients of correlation between P uptake by soybean from an acid oxisol and P extracted by chemical extractants, after the two incubation periods, were found: 0.902^** for 0.01M CaCl₂; 0.823^** for anion-exchange resin; 0.720^** for 0.03N NH₄F+0.025N HCl; –0.037 (n.s.) for 0.025N H₂SO₄+0.050N HCl.The acid NH₄F solubilized residual calcined aluminum phosphate particles, and double acid extracted P from residual apatite particles, thus accounting for their poorer performances in predicting availability of fertilizer P.The relative efficiencies of the rock phosphates could largely be predicted after an incubation period of only three days. This finding attests to the presence in these rock phosphates of an easily soluble fraction of P which is not indicative of the degree of reactiveness of the phosphate as a whole.on leave at the Agricultural University during 1977.     

Foraging behaviour of Scymnus coccivora Ayyar against cotton mealybug Phenacoccus solenopsis Tinsley

Predation is one of the significant biotic mortality factors reducing the insect pest population as functional response and the numerical response of the predator are the key factor regulating the population dynamics of predator prey species. This study is aimed to evaluate the functional response of all the developmental stages of Scymnus coccivora Ayyar (Coleoptera: Coccinellidae) against the different densities of cotton mealybug, Phenacoccus solenopsis (Tinsley) (Hemiptera: Pseudococcidae) and the numerical response of female predator. Experiments were carried out in controlled environment laboratory conditions at 25 ± 1 °C temperature, 60 ± 5% relative humidity and photoperiod of 16 h. Number of eggs consumed, number of eggs laid and the Efficiency of Conversion of Ingested food (ECI) were recorded daily. Results from the study revealed that all the developmental stages of S. coccivora exhibited a Type II response. Different parameters such as attack rate (a’), handling time (T_h) and the maximum rate of predation were estimated using Roger’s random attack equation and Holling Disc equation in which Rogers random attack equation was found best fit. Female has shown the highest attack rate (a’) followed by IV^th instar grub, male, III^rd, II^nd and I^st instar grub. With low handling time, IV^th instar grub has shown maximum predation rate of 76.40 per day followed by female (75.86), male (58.79), III^rd (22.84), II^nd (19.65) and I^st instar grub (15.39). The numerical response increase was curvilinearly related to different prey densities with the highest number of eggs (11.8 ± 3.44) produced at highest prey density (160). The Efficiency of Conversion of Ingested food (ECI) was highest (64.49 ± 8.03) at prey density of 10. Understanding the factors that lead to variation in functional response of predator in natural population will advance our understanding of the effects of predation on individual and the effectiveness of coccinellid predators as biocontrol agent against cotton mealybug.     

Sexual dimorphism of the human corpus callosum from three independent samples: Relative size of the corpus callosum

Three independent autopsy samples of brains without apparent neuropathology were studied to ascertain whether there was sexual dimorphism in the human corpus callosum (CC). Using planimetric measurements on midsagittal brain sections, several morphometric features of the CC were studied: total callosal area, maximum dorsoventral splenial width, the posterior one fifth of the total area of the CC (mostly splenium), and brain weight. Ratio data correcting for brain size were also studied. In all samples, absolute brain size was larger in males, and significantly so. Measurements of splenial dorsoventral width were higher in females than males, but not significantly, except in the Australian sample. Total callosal area was absolutely higher in the Australian female sample than in males, and almost equal in the two American samples, without statistically significant differences. The posterior one-fifth area (splenium) was larger for females in each of the samples. The variables which were corrected for brain size were usually significantly larger in females, although this pattern varied in each sample. The statistical pattern of sexual dimorphism for the human CC differs from that found in most other neural structures, such as the amygdaloid nucleus, cerebellum, hippocampus, and thalamus. The absolute sizes of these structures are always significantly larger in males. When corrected for brain size, the relative sizes are not significantly larger. The CC is the only structure to show a larger set of relative measures in females. © 1993 Wiley-Liss, Inc.     

Inventoring the fungi of Panama

Records of fungi in Panama scattered in literature are presented in a preliminary annotated checklist which is published in Panama. It includes 1807 species and subspecific taxa in 646 genera. The data allow to trace more than 100 years of history of mycology in Panama, presented here for the first time. The species richness is analyzed numerically with respect to the systematic position of the species and their ecology. Considering the numbers of records for different regions of Panama, a comparison with numbers of species published for some other neotropical countries, as well as recent experience collecting fungi in Panama, the incompleteness of the checklist is evident. Values of relative species richness of different systematic groups in Panama compared to values of the same groups as known worldwide, show that our knowledge is fragmentary in Panama especially for Agaricales, Uredinales, and some groups of microfungi. We are still in the pioneer phase of mycological investigation in Panama.     

Point Estimation on Relative Risk under Inverse Sampling

When the underlying disease is rare, to control the coefficient of variation for the sample proportion of cases, we may wish to apply inverse sampling. In this paper, we derive the uniformly minimum variance unbiased estimator (UMVUE) of relative risk and its variance in closed form under inverse sampling. On the basis of a Monte Carlo simulation, we demonstrate that using the UMVUE of relative risk can substantially reduce the mean-squared-error of using the maximum likelihood estimator, especially when the number of index cases in both comparison samples is small. For a given fixed total cost, we include a program that can be used to find the optimal allocation for the number of index cases to minimize the variance of the UMVUE as well.     

Trypanosoma gambiense: Blocking ability of parasite and macrophage homogenates on attachment during phagocytosis

This study deals with the ability of the parasite and macrophage homogenates, each fractionated into soluble and insoluble parts, to block the attachment of Trypanosoma gambiense on the macrophage in the process of phagocytosis. The soluble parasite fraction and the insoluble macrophage fraction both showed a high blocking ability. However, the ability of the parasite fraction was completely lost on trypsin digestion, while that of the macrophage was not changed at all. In addition, sonication of the macrophage did not change its blocking ability.     

Tracking soluble and nanoparticulated titanium released in vivo from metal dental implant debris using (single-particle)-ICP-MS

BackgroundThis work studies the presence of the Ti, Al and V metal ions and Ti nanoparticles released from the debris produced by the implantoplasty, a surgical procedure used in the clinic, in rat organs.MethodsThe sample preparation for total Ti determination was carefully optimized using microsampling inserts to minimize the dilution during the acid attack of the lyophilized tissues by a microwave-assisted acid digestion method. An enzymatic digestion method was optimized and applied to the different tissue samples in order to extract the titanium nanoparticles for the single-particle ICP-MS analysis.ResultsA statistically significant increase was found for Ti concentrations from control to experimental groups for several of the studied tissues, being and particularly significant in the case of brain and spleen. Al and V concentrations were detected in all tissues but they were not different when comparing control and experimental animals, except for V in brain. The possible presence of Ti-containing nanoparticles mobilized from the implantoplasty debris was tested using enzymatic digestions and SP-ICP-MS. The presence of Ti-containing nanoparticles was observed in all the analyzed tissues, however, differences on the Ti mass per particle were found between the blanks and the digested tissue and between control and experimental animals in some organs.ConclusionThe developed methodologies, both for ionic and nanoparticulated metal contents in rat organs, have shown the possible increase in the levels of Ti both as ions and nanoparticles in rats subjected to implantoplasty.