Cooperative behavior and social organization of the Swallow-tailed Manakin (Chiroxiphia caudata)

Summary The mating system of the Swallow-tailed Manakin (Chiroxiphia caudata) is a type of non-resource based polygyny in which males aggregate at traditional sites or leks to perform cooperative displays. Each lek and all its contained courts are used communally by a group of 4–6 males. Within the group a linear dominance hierarchy exists. Position in the hierarchy persists within and between years and at all courts and is inherited in linear sequence. The dominant male of the group behaves as a sentinel calling repeatedly from a high perch in an attempt to attract females to a court.When a female arrives, two or three males engage in a cooperative precopulatory dance, the Jump Display. This is followed by a Solo Precopulatory Display performed by a single male who, if successful, will copulate with the female. With rare exception, the dominant male performs all Solo Displays and all copulations.Display sequences that include both a Jump Display and Solo Precopulatory Display are more likely to lead to copulation than those consisting of only one part. Thus, the subordinates who help the dominant perform the dance are expending energy that increases his fitness without receiving any immediate benefit themselves. Several factors that may have contributed to the evolution of the mating system and cooperative displays of this species are considered.     

Cellulose degradation by Lulworthia floridana and other lignicolous marine fungi

Gravimetric analyses of cellulose (Solka Floc) utilization by representative marine Ascomycetes, including Lulworthia floridana, Lindra sp., Torpedospora sp. and Halosphaeria mediosetigera, have shown noteworthy activity based on loss of weight of cellulose by the various fungi. Particularly striking activity is evidenced by L. floridana and Torpedospora sp., with >50% cellulose degradation after 3 weeks of fungal growth. Comparable studies with the deuteromycete, Dendryphiella salina, showed >50% loss within 6 days. Dissimilar responses by various L. floridana isolates are noted. Intensive degradative activity at pH's of 6 to 8 is common along with negligible amounts of cellulase (Cx units). Adsorption of the enzyme to the mycelia or to the cellulose particles in the medium is suggested. Earlier laboratory analyses of fungal degradation of Manila cordage compare favorably with present gravimetric studies and support field observations on the significance of fungal infestation of wood, particularly that incited by the Lulworthia floridana group.This work was supported by Grant GM 12482 from the National Institute of Health and Office of Naval Research Contract No. 137-792 to the Institute of Marine Sciences, University of Miami. Contribution No. 950 from the Institute of Marine Sciences, University of Miami.     

Distribution and leaching of methyl iodide in soil following emulated shank and drip application

Methyl iodide (MeI) is a promising alternative to methyl bromide in soil fumigation. The pest-control efficacy and ground water contamination risks of MeI as a fumigant are highly related to its gas-phase distribution and leaching after soil application. In this study, the distribution and leaching of MeI in soil following shank injection and subsurface drip application were investigated. Methyl iodide (200 kg ha(-1)) was directly injected or drip-applied at a 20-cm depth into Arlington sandy loam (coarse-loamy, mixed, thermic Haplic Durixeralfs) columns (12-cm i.d., 70-cm height) tarped with virtually impermeable film. Concentration profiles of MeI in the soil air were monitored for 7 d. Methyl iodide diffused rapidly after soil application, and reached a 70-cm depth within 2 h. Relative to shank injection, drip application inhibited diffusion, resulting in significantly lower concentration profiles in the soil air. Seven days after MeI application, fumigated soil was uncapped, aerated for 7 d, and leached with water. Leaching of MeI was significant from the soil columns under both application methods, with concentrations of >10 mug L(-1) in the early leachate. The leaching was greater following shank injection than drip application, with an overall potential of 33 g ha(-1) for shank injection and 19 g ha(-1) for drip application. Persistent residues of MeI remaining in soils after leaching were 50 to 240 ng kg(-1), and the contents were slightly higher following shank injection than drip application. The results suggest that fumigation with MeI may pose a risk of ground water contamination in vulnerable areas.     

Temporal changes in soil partitioning and bioaccessibility of arsenic, chromium, and lead

The hazard imposed by trace element contaminants within soils is dependent on their ability to migrate into water systems and their availability for biological uptake. The degree to which a contaminant may dissociate from soil solids and become available to a target organism (i.e., bioaccessibility) is therefore a determining risk factor. We used a physiologically based extraction test (PBET) to estimate the bioaccessible fraction of arsenic-, chromium-, and lead-amended soil. We investigated soils from the A and B horizons of the Melton Valley series, obtained from Oak Ridge National Laboratory site, to address temporal changes in bioaccessibility. Additionally, common extractions that seek to define reactive pools of metals were employed and their correlation to PBET levels evaluated. With the exception of Pb amended to the A horizon, all other treatments exhibited an exponential decrease in bioaccessibility with incubation time. The bioaccessible fraction was less than 0.2 mg kg(-1) within 30 d of incubation for As and Cr in the A horizon and for As and Pb within the B horizon; Cr in the B horizon declined to nearly 0.3 mg kg(-1) within 100 d of aging. The exchangeable fraction declined with incubation period and, with the exception of Pb, was highly correlated with the decline in bioaccessibility. Our results demonstrate limited bioaccessibility in all but one case and the need to address both short-term temporal changes and, most importantly, the soil physiochemical properties. They further reveal the importance of incubation time on the reactivity of such trace elements.     

Release of Cryptosporidium and Giardia from dairy cattle manure: physical factors

Various physical factors affecting the release rate of naturally occurring Cryptosporidium parvum oocysts and Giardia duodenalis cysts from dairy manure disks to sprinkled water were studied. The investigated factors included temperature (5 or 23 degrees C), manure type (calf manure, a 50% calf and 50% cow manure mixture, and a 10% calf and 90% cow manure mixture), and water application method (mist or drip) and flow rate. Effluent concentrations of manure and (oo)cysts were always several orders of magnitude below their initial concentration in the manure, decreased gradually, and exhibited persistent concentration tailing. Release of manure and (oo)cysts were found to be related by a constant factor, the so-called release efficiency of (oo)cysts. A previously developed (oo)cyst release model that included these release efficiencies provided a satisfactory simulation of the observed release. An effect of temperature on the release of manure and (oo)cysts was not apparent. The manure and (oo)cyst release rates from cow manure decreased faster than those from calf manure, and (oo)cyst release efficiencies from cow manure were higher than those from calf manure. In comparison with mist application, dripping water resulted in higher release rates of manure and (oo)cysts and in higher (oo)cyst release efficiencies due to the increased mechanical forces associated with droplet impact. Mist application at a higher flow rate resulted in faster release, but did not affect the (oo)cyst release efficiencies. The data and modeling approach described herein provide insight and an enhanced ability to describe the influence of physical factors on (oo)cyst release.     

Spatial distribution of 3H, 90Sr, 137Cs and (239,240)Pu in surface waters of the Pacific and Indian Oceans--GLOMARD database

The data stored in the IAEA's Global Marine Radioactivity Database (GLOMARD) developed in the framework of the IAEA's project "Worldwide Marine Radioactivity Studies (WOMARS)" have been evaluated for Pacific and Indian Ocean surface waters. Four anthropogenic radionuclides-- 3H, 90Sr, 137Cs and (239,240)Pu --have been chosen as the most representative of anthropogenic radioactivity in the marine environment, comprising beta, gamma and alpha-emitters which are the most frequently analysed in the marine environment and which have (with the exception of tritium) the highest potential contribution to radiation doses to humans via seafood consumption. For the purposes of this study, the Pacific and Indian Oceans were divided into latitudinal boxes for which average radionuclide concentrations were estimated for the year 2000. The highest concentrations have been observed in the Japan Sea/East Sea and the North-West Pacific Ocean, the lowest in the Southern Ocean.     

Minor and trace elements in the shell of Patella aspera (Röding 1798)

Specimens of the limpet Patella aspera were collected from a clean, coastal marine site and a contaminated estuary on the south coast of Portugal. The shells were analysed individually for their minor (Mg, Sr) and trace element (Fe, Mn, Zn) content. Mean concentrations of these elements in the shell of P. aspera were 4651, 1318, 35.8, 29.9 and 5.5 microg g(-1), respectively. The elemental concentrations exhibited both a marked intra- and inter-population variability. Despite the variability within individual populations, significant differences in the trace element composition were apparent between the shells taken from the two sites. Small shells (< 2 g) provided the best resolution between sites for both manganese and iron. Differences in zinc were best resolved for larger shells. The shell of P. aspera has an extraordinarily high magnesium concentration, which is insensitive to gross salinity differences, and a trace metal assemblage that can be interpreted in terms of environmental exposure. On these grounds, it is recommended that the shell of P. aspera is a tissue for potential use in environmental trace metal monitoring.     

Investing in safety an analytical precautionary principle

PROBLEM: Governments and businesses must respond to increasing safety requirements and balance the associated costs with productivity and competing pressures. METHOD: A real options approach has been introduced for decision making in the private sector; this approach is adapted for regulatory decisions that can involve irreversible and uncertain safety impacts, social costs that differ from private costs, and differences in perception among the stakeholders. RESULT AND IMPACT ON INDUSTRY AND GOVERNMENT: The outcome is an economic decision gage that determines if it is optimal to invest in safety even if the estimated costs significantly exceed the estimated benefits. Applications potentially include safety decisions related to aviation, ground transportation, pipelines, nuclear facilities, natural disaster planning, and terrorism, among others.     

Land treatment and the toxicity response of soil contaminated with wood preserving waste

Soils contaminated with wood preserving wastes, including pentachlo-rophenol (PCP) and creosote, are treated at field-scale in an engineered prepared-bed system consisting of two one-acre land treatment units (LTUs). The concentration of selected indicator compounds of treatment performance included PCP, pyrene, and total carcinogenic polycyclic aromatic hydrocarbons (TCPAHs) was monitored in the soil by taking both composited soil samples at multiple points in time, and discrete soil samples at two points in time. The mean concentration of the indicator compounds and the 95-percent confidence interval (CI) of the composite and discrete samples agreed relatively well, and first-order degradation rate kinetics satisfactorily represented the mean chemical concentration loss of indicator compounds in the LTU. Toxicity of the soil, as measured by Microtox^TM assay of the soil extracts, indicated that toxicity reduction corresponded with indicator compound disappearance. No toxicity effects were observed with time in treated layers of soil (lifts) buried beneath highly contaminated lifts of newly applied soil. This indicated that vertical migration of soluble contaminants from such lifts had little effect on the microbial activity in the underlying treated soil.     

Green Symbolism in the Genetic Modification Debate

The character of the current controversy over geneticallymodified (GM) agriculture, typified by protesters' use of emotivesymbolism, has been largely inspired by the Green movement'snon-governmental organizations and political parties. This articleexplores the deeper philosophical and spiritual motivations of the Greenmovement, to inquire why it is implacably opposed to GM agriculture. TheGreen movement's anti-capitalism, exemplified by the hate-symbol statusof Monsanto as the company pioneering GM crops, is viewed within thewider context of alienation in the modern era. A complex of meanings isseen in Frankenstein as the focal symbol of GM protests, includingperceptions of risk, fears of the remixing of living identities seen ingenetic engineering, and resentment at the spiritual nihilism of thereduction of life to the digital code of DNA. By contrast, RobertGoodin's Green Theory of Value, which postulates the deep psychologicalimportance of nature in locating the self in a meaningful context largerthan ourselves, can explain the power of the Green symbol of thethreatened environment, Gaia. The advent of GM agriculture seems toimply that capitalism and technology can now enframe nature itself,leaving a world devoid of natural myth or meaning, with no escape fromthe alienation and nihilism of modernity. The central question posed forprotagonists of the GM debate is whether their agenda is based on thesepowerful but mythical conceptions of the environment, or whetherpreservation of the real environment is their primary ethic.