9. The algal flora of the Primorsky Region, Russian Far East

A survey of the freshwater algal flora of the Primorsky Region, Russian Far East, is presented. During more than 70 years of investigations 1659 species (including varieties and forms 2276 taxa) belonging to 346 genera of different groups of algae have been recorded from this territory. The Primorsky Region is rich in habitats attractive to algae-rivers, lakes, reservoirs, and ponds. The details of the distribution of algae in different types of waterbodies have been examined. The algal flora of the region is comparable to the areas, and its taxonomical structure is typical for Eurasia. From this territory some new species and varieties have been described — Achnanthes chankensis, Cymbella ventricosa var. hankensis, Surirella alisoviana, and others. The flora includes some rare species — Fragilaria magocsyi, Perone dimorpha, and Heterothrix monochloron, and some endemics of Asia — Navicula scutelloides var. baicalensis, N. globulifera var. nipponica, Gomphonema sphaerophorum, and Surirella tientsinensis.     

Analysis and assessment of heavy metals pollution in soils around a Pb and Zn smelter in Baoji City,Northwest China

Soil heavy metal pollution from mining activities is potentially harmful to human health through the food chain. In this study, a total of 43 soil samples were collected from a depth of 0–20 cm from fields close to a Pb and Zn smelter. The samples were used to: 1) analyze the pollution level of heavy metals (Pb, Zn, Cr, and Cu) and spatial distribution pattern; 2) evaluate the degree of accumulation and enrichment, potential ecological risk, and human health risk; and 3) perform source apportionment in Fengxiang County, Shaanxi Province of China. The results showed that the concentration ranged from 43.67 to 189.55, 131.43 to 239.53, 74.77 to 112.25, and 24.69 to 37.71 mg·kg^?1 for Pb, Zn, Cr, and Cu, respectively, and the mean concentration for Pb, Zn, Cr, and Cu was 129.46, 192.85, 91.98 and 31.67 mg·kg^?1, respectively. The concentrations were greater than the Shaanxi Province background values, while they were lower than the second-level limits of Environmental Quality Standard for Soils of China (EQSS). The spatial distribution of heavy metal contents showed a banded in soil except Cu. The spatial distribution pattern and pollution assessment indexes (I_geo, EF) indicated that the investigated metals had been accumulated in the study areas, and implied significant influences from anthropogenic activities, local meteorological situation, and soil properties. The ecological risk assessment showed that the risks were relatively low (RI<150). Compared with the exposure risk for adults, that for children was significantly greater. The ingestion of heavy metals in the soils by humans was the main exposure pathway compared with the dermal exposure. There may be a risk of noncarcinogenic adverse health effects (HQ < 1, 0.377 ≤ HI≤1.553) on children, but the adults were unlikely to experience obvious adverse health effects (HQ < 1, HI < 1). The carcinogenic risk of Cr for adults and children was at an unacceptable level. The carcinogenic and noncarcinogenic risks were in the order of children > adults. The correlation analysis showed that Pb, Cr, and Cu have identical anthropogenic and natural sources, while Zn has another identical source. This study could provide a basis for the sustainable management of this region by reducing metal inputs and to protect soils from long-term heavy metal accumulation.     

Rare species habitat suitability assessment and reliability evaluation of an expert-based model: A case study of the insectivorous plant Pinguicula crystallina Sibth. et Smith subsp. hirtiflora (Ten.) Strid (Lentibulariaceae)

The development of habitat suitability models requires a large amount of data which are rarely available. In this case, researchers need to get information on the ecological features of the studied species, based on the opinion of experts or on the literature, to construct a qualitative model. However, such models cannot be rigorously evaluated, as in most cases absence points are not available. In this paper, we assess the habitat suitability for a vulnerable insectivorous plant, Pinguicula crystallina Sibth. et Smith subsp. hirtiflora (Ten.) Strid (Lentibulariaceae) in the Campania region. Our aim was to develop an expert-based, presence-only model in support of possible conservation actions. Topographic and geological features of this species suggested by the literature were used in our model. Both the Boyce index and field surveys were chosen to evaluate the model's reliability. During field surveys, 31 absence sites and 1 new presence site were identified, and differences between sites with regard to water chemistry and quality were investigated, water being an element in the species habitat. Factors that affect reliability of the model, such as the lack of a large amount of information on the species and the limited spatial resolution of geographical information system data, are discussed.     

Concomitant Information in Competing Risk Analysis

A competing risk model, accommodating both Type I censoring and random withdrawals, is expanded to incorporate concomitant information by allowing the parameters of the underlying distributions to be a linear function of two covariates. The model is developed for two competing risks, one following a Weibull distribution and the other a Rayleigh distribution, and random withdrawals following a Weibull distribution. A method is developed for testing the equality of the coefficients for a given covariate for each of the competing risks using MLE'.     

Neurofilament Proteins Are Distributed in a Diminishing Proximodistal Gradient Along Rat Sciatic Nerve

Neurofilament (NF) proteins are distributed in a diminishing proximodistal gradient along rat sciatic nerve when compared with total noncollagen or other proteins in nerve. About a twofold decline of NF proteins can be detected by quantitating nerve proteins that have been separated by gel electrophoresis. A similar decrease of immunoreactivity to each NF subunit is seen in distal nerve segments when noncollagen nerve proteins are immunoblotted. Parallel decreases occur in all three NF proteins, thereby maintaining neurofilament subunit stoichiometry along the neuraxis. The same NF gradient can be detected when the NF contents in nerve branches to the gluteus and gastrocnemius muscles are compared with each other and with those in nerve segments taken from the same proximodistal levels of the parent sciatic nerve. The gradient of NF proteins increases during postnatal development and is readily detected by postnatal day 16. During the same period of development, the heavy NF subunit appears for the first time and is rapidly incorporated throughout the sciatic nerve. Hence, the NF gradient becomes manifest during the development and maturation of the adult form of the axonal cytoskeleton. The basis for the proximodistal gradient of NF proteins in peripheral nerve is presently unknown. The extent of the gradient cannot be accounted for on the basis of diminishing numbers of nerve fibers or increasing amounts of other nerve proteins, e.g., collagen, in distal nerve. An alternative interpretation is that the gradient reflects a low level of NF protein turnover during axonal transport.