The cross-scale interplay between social and biophysical context and the vulnerability of irrigation-dependent societies: archaeology's longterm perspective. Ecology and Society 15(3): 31.

X-ray diffraction and infrared absorption spectra show that the spicules of the common tropical ascidian, Herdmania momus, are mineralized with vaterite. These are the first strictly marine organisms known to normally precipitate vaterite. The biomineralization of vaterite may constitute another link between the urochordates and vertebrates. The vaterite of ascidian spicules immersed in natural seawater remains mineralogically unchanged for 1 year, which indicates that vaterite may be preserved transiently in marine sediments.

Sildenafil citrate, marketed as Viagra s , for the treatment of erectile dysfunction, has a proven record of safety in humans as predicted by the results of extensive pharmacological and toxicological testing in animals and in vitro, and confirmed by pharmacokinetic exposure data. The aim of this paper is to review succinctly the main findings resulting from these experiments. Daily doses of sildenafil, within and far beyond the human therapeutic range, were given to dogs and rodents for up to 1 and 2 y, respectively. Plasma analyses were conducted to determine the exposure to sildenafil. We found species-specific effects in dogs (Beagle pain syndrome), mice (marked intestinal dilatation) and rats (adaptive reversible hepatocellular hypertrophy associated with secondary thyroid hypertrophy). All these effects in rodents and dogs have no relevance to humans. Morphometric thickness measurements of the retinal layers carried out in response to clinical observations of visual disturbances in humans indicated no difference between treated and control rats and dogs after up to 24 months of treatment. There was no evidence of histopathologic damage to any structures of the visual pathway. Sildenafil had no effects on fertility, no teratogenic potential, was not genotoxic and has no carcinogenic potential. In rats and dogs, safety ratios were 40:1 and 28:1, respectively, in terms of exposure over 24 h (AUC 24 h ) and 19:1 and 8:1, respectively, in terms of peak plasma concentration (C max ). These safety ratios illustrate the separation between exposure to sildenafil of animals at large nontoxic doses and the much smaller human therapeutic exposure. This profile highlights the very low risk of human toxicity for sildenafil. The favourable results of the nonclinical safety evaluation of sildenafil in established animal models have been confirmed by many years of clinical experience during the development and marketing of sildenafil.

During the middle Sedentary period (ca. A.D. 1000-1070) in the deserts of southern and central Arizona, crowds from near and far regularly gathered at the centers of Hohokam villages to participate in ritual ballcourt festivities. These events were ideal venues for barter and exchange, leading some theorists to hypothesize that periodic marketplaces were associated with the ritual ballgames. Recent ceramic provenance and vessel-form evidence from the Phoenix basin have shown that the production of decorated and utilitarian pots was highly concentrated during this time and large numbers of bowls and jars were evenly distributed to far flung consumers. These findings have supported the marketplace hypothesis, suggesting that an efficient and reliable mechanism was available for moving large numbers of commodities across the region. The high volume of ceramic transactions, however, seems to have placed the Hohokam case beyond the capabilities of nascent marketplaces documented from ethnohistoric and ethnographic evidence. In this paper, we support the idea that market-place barter was a central component of the Hohokam economy by presenting new ceramic data from the lower Salt River valley, which temporally links the demise of the ballcourt ceremonialism with a transformation in the organization of pottery production and distribution. We then examine some unusual circumstances pertaining to the Hohokam regional system that may help to explain how consumers could have so heavily depended on a network of horizontally organized, periodic marketplaces for basic necessities like earthenware containers.

No abstract

The solitary phlebobranch ascidian Corella inflata, originally described by Huntsman in 1912 but later synonymized with C. willmeriana Herdman, 1898, is now reinstated as a separate species based on comparative morphology of adults, sperm, and tadpoles. Corella inflata is probably largely or completely self-fertilizing, broods its eggs and embryos until well after hatching of the tadpole larvae, and is confined in its distribution to shallow-water (0.1–18 m depth) areas of northwestern Washington and British Columbia. Corella willmeriana appears to be both self- and cross-fertilizing, does not brood its eggs, and is more widespread in distribution, occurring from southern Alaska to southern California and at least as deep as 50 m; it is rarely encountered at the sea surface. The two Corella species differ morphologically from the European Corella parallelogramma and the Japanese C. japonica and C. japonica asamushi. Differential spawning latencies are discussed and the possibility that C. inflata evolved through stasipatric speciation is proposed.

Toxicants in polluted environments are often patchily distributed. Hence, rather than being passive absorbers of pollution, some organisms have evolved the ability to detect and avoid toxicants. We studied the avoidance behavior of Physella columbiana, an aquatic pulmonate snail, in a pond that has been polluted with heavy metals for more than 120 years. Populations of this snail are rare at reference sites and are only robust at heavy-metal-polluted sites. We hypothesized that the snails are able to persist because they have evolved the ability to minimize their exposure to metals by actively avoiding metals in their environment. Using a Y-maze flow tank, we tested the avoidance behavior of snails to heavy-metal-polluted sediments and single-metal solutions of cadmium, zinc, or lead. We also tested the avoidance behaviors of the snails' laboratory-reared offspring raised in nonpolluted conditions. In addition, we tested the avoidance behavior of a small population of snails from a reference pond. Although all the snails we tested were able to detect low concentrations of heavy metals, we found that snails from the polluted site were the most sensitive, that their offspring were somewhat less sensitive, and that snails from the reference site were the least sensitive. This suggests that the ability of polluted-site snails to avoid heavy metals is both genetic and environmental. The concentrations of metals avoided by the snails from the polluted site were below the levels found at hot spots within their natal pond. The snails may be able to persist at this site because they decrease their exposure by moving to less-polluted sections of the pond. One application of our findings is the use of aquatic snails and our Y-maze design as an inexpensive pollution detector. Environmental pollutants such as lead, zinc, and arsenic are a problem throughout the world. People in underdeveloped countries often lack sophisticated pollution detection devices. We have developed a behavioral assay of aquatic pollution that is easy to use, is extremely sensitive (detection below 10 ppb), and can be constructed for fewer than 100 US dollars. Pulmonate snails are widely distributed in tropical, subtropical, and temperate parts of the globe, and they are often common in polluted waters. For countries such as India and Bangladesh, which must test thousands of shallow wells for possible contamination with heavy metals, our assay would be a good initial test. Once snails detected metals, then those samples could be confirmed by spectrometers. We encourage scientists in underdeveloped nations to consider our assay as an option.

Abstract. The lesions associated with parasitic infestation in 1 156 wild-caught, laboratory-maintained nonhuman primates (Macaca fascicularis, Macaca mulatta, and Papio spp) are described. The two most common parasites seen were lung mites (Pneumonyssus spp) and nodular worms (Oesophagostomum spp). In addition, in cynomolgus monkeys (Macacafascicularis) only, Nochtia nochti was a frequent pathogen. The etiology of mineralized fibrotic nodules in the mesentery of cynomolgus monkeys was thought to be infection with Paragonimus westermani, the oriental lung fluke.The use of nonhuman primates in biological research has prompted a need for more information on the natural diseases of these species. At the same time, it has provided a means by which this information can be obtained in significant quantities. Many toxicological laboratories, including Huntingdon Research Centre, currently use wild-caught, laboratory-maintained primates, which present the pathologist with a wide variety of parasitic diseases. Since these primates have spent at least part of their lives in 'natural' surroundings, they have been exposed to the infections, intermediate hosts, and vectors of parasitic diseases prevailing in the areas of their capture and presumably their habitat.The documentation of these diseases and lesions is important for management and conservation of wild primate populations and for preventative medicine of captive ones. In the last ten to 20 years there has been a vast increase in interest and documentation in primate 12. 13. 15* 18-20-23.28 This paper reports the incidence of parasites and parasitic lesions found in 1 156 nonhuman primates used in toxicological studies. Materials and MethodsFour hundred seventy-two cynomolgus monkeys (Macaca fascicularis), 450 rhesus monkeys (Macaca mulatta), and 234 baboons (Papio spp) were obtained from a commercial s u p plier, housed individually, and kept in relative isolation of approximately 22°C. They were fed a standard dry diet preparation supplemented with bread, fresh fruit, and vegetables. Vitamins C and Blr were added to the drinking water, which was available ad libitum.The monkeys were from various toxicological experiments designed for drug safety evaluation, and both untreated control and treated groups were included in the survey. The monkeys ranged from 1.5 to 4 years of age and all were wildcaught and laboratory-maintained.All monkeys surviving their experimental procedure were killed by intravenous injection of sodium pentobarbitone ("Expiral," Abbott Laboratories, Queensborough, Kent, U.K.). All body systems were examined macroscopically and any lesions were noted and described. Representative portions of all organs and lesions were fixed in 10% neutral buffered formalin, embedded in parafin, sectioned at 5 pm, and stained with hematoxylin and eosin (HE).A full spectrum of parasitological techniques was not done due to the nature of the studies, and diagnoses were made by a combination of macroscopic observation and histological examination. ResultsThe inciden...