Male–female socio-spatial relationships and reproduction in wild chimpanzees

Recent research on primates and other taxa has shown that the relationships individuals form with members of the same sex affect their reproductive success. Evidence showing that intersexual relationships also influence reproduction, however, is more equivocal. Here, we show that male chimpanzees living in an exceptionally large community display long-term tendencies to associate with particular females. These association patterns are likely to arise because individuals of both sexes selectively range in specific areas of the communal territory, with males inheriting the ranging patterns of their mothers. These differentiated male–female socio-spatial relationships involved males of widely varying ranks, and their effect on reproduction is as strong as that of male dominance rank, which in turn is as strong a predictor of reproductive success at Ngogo as in other smaller chimpanzee communities. These results show that male–female socio-spatial relationships can play a large role in chimpanzee male reproductive strategies, although they probably neither weaken nor strengthen the relationship between male dominance rank and reproductive success. Our results linking male–female socio-spatial relationships to reproduction in chimpanzees suggest that the gap between the social and mating systems of humans and their closest living relatives may not be as large as previously thought.     

Infrared Measurement of Fluorocarbons,Carbon Tetrachloride,Carbonyl Sulfide,And Other Atmospheric Trace Gases

A cryogenic procedure for concentrating trace gases in the atmosphere has been developed and applied to the ambient air at Research Triangle Park, NC, Atlantic Beach, NC, and New York City. The concentrated gases have been analyzed by long path infrared absorption spectroscopy, with a detectability down to partial pressures of 10^?11 atmospheres. Carbonyl sulfide has been detected at partial pressures in the range 1 × 10^?10 atm. to 3 × 10^?10 atm. Carbon tetrachloride was always detected with a rather narrow partial pressure range of 0.7 × 10^?10 atm. to 1.1 × 10^?10 atm. Fluorocarbon-11 values ranged from about 1.3 × 10^?10 atm. at Research Triangle Park to 8 × 10^?10 atm. at New York City. Fluo-rocarbon-12 covered the range 1.8 × 10^?10 atm. to 1.0 × 10^?9 atm. Hydrocarbon pollutants varied widely in concentration, but were always detected, even in the clean rural air.     

Biochemical responses during starvation and subsequent recovery in postlarval Pacific white shrimp,Penaeus vannamei

Postlarval shrimp, Penaeus vannamei Boone, 1931, were held individually in cages and exposed to two feeding regimes. One group was starved for 12 d and then fed during the following 12 d. A second group was fed throughout the 24 d study. Four individuals were sampled from each of the two groups on Days 0, 1, 2, 4, 8, 12, 13, 14, 16, 20, and 24. Molting and growth among the starved-fed postlarvae stopped after 2 d starvation, while fed postlarvae increased significantly in size throughout the 24 d study. Among the starved-fed postlarvae, water content increased rapidly in response to starvation. DNA and sterol concentrations increased significantly during starvation due to selective catabolism of cellular components. After 12 d, RNA concentration was not significantly different between the fed and starved-fed postlarvae, but became significantly higher in the starved-fed postlarvae 48 h after feeding resumed. Triacylglycerol reserves were severely depleted during the first day of starvation, while protein concentrations began to decrease after the second day of starvation. RNA, protein, and the polyamines spermidine and spermine, when expressed as a ratio to DNA, decreased in response to starvation. Concentrations of all measured parameters in the starved-fed postlarvae returned to levels similar to those in the fed group 8 to 12 d after feeding resumed. Results of this study suggest that triacylglycerol provides energy during short periods of starvation, while protein is utilized during prolonged starvation. The ratios of RNA:DNA, protein:DNA, spermidine:DNA, spermine:DNA, two unidentified amine compounds, and percent water content are all useful indicators of prolonged nutritional stress in postlarval P. vannamei.     

The evolution of female social relationships in nonhuman primates

Considerable interspecific variation in female social relationships occurs in gregarious primates, particularly with regard to agonism and cooperation between females and to the quality of female relationships with males. This variation exists alongside variation in female philopatry and dispersal. Socioecological theories have tried to explain variation in female-female social relationships from an evolutionary perspective focused on ecological factors, notably predation and food distribution. According to the current “ecological model”, predation risk forces females of most diurnal primate species to live in groups; the strength of the contest component of competition for resources within and between groups then largely determines social relationships between females. Social relationships among gregarious females are here characterized as Dispersal-Egalitarian, Resident-Nepotistic, Resident-Nepotistic-Tolerant, or Resident-Egalitarian. This ecological model has successfully explained differences in the occurrence of formal submission signals, decided dominance relationships, coalitions and female philopatry. Group size and female rank generally affect female reproduction success as the model predicts, and studies of closely related species in different ecological circumstances underscore the importance of the model. Some cases, however, can only be explained when we extend the model to incorporate the effects of infanticide risk and habitat saturation. We review evidence in support of the ecological model and test the power of alternative models that invoke between-group competition, forced female philopatry, demographic female recruitment, male interventions into female aggression, and male harassment. Not one of these models can replace the ecological model, which already encompasses the between-group competition. Currently the best model, which explains several phenomena that the ecological model does not, is a “socioecological model” based on the combined importance of ecological factors, habitat saturation and infanticide avoidance. We note some points of similarity and divergence with other mammalian taxa; these remain to be explored in detail. Received: 30 September 1996 / Accepted after revision: 20 July 1997     

Reactive oxygen species responsible for the enhanced desorption of dodecane in modified Fenton's systems.

The enhanced treatment of sorbed contaminants has been documented in modified Fenton's reactions; contaminants are desorbed and degraded more rapidly than they desorb by fill-and-draw or gas-purge desorption. The reactive species responsible for this process was investigated using dodecane as a model sorbent. Hydroxyl radical, hydroperoxide anion, and superoxide radical anion were generated separately to evaluate their roles in enhanced dodecane desorption. Dodecane desorption from silica sand over 180 minutes was negligible in gas-purge systems and in the hydroxyl radical and hydroperoxide anion systems. In contrast, enhanced desorption of dodecane occurred in superoxide systems, with >80% desorption over 180 minutes. Scavenging of superoxide eliminated the enhanced desorption of dodecane in both superoxide and modified Fenton's systems, confirming that superoxide is the desorbing agent in modified Fenton's reactions. Conditions that promote superoxide generation in Fenton's reactions may enhance their effectiveness for in situ subsurface remediation of sorbed hydrophobic contaminants.     

Fate of selenium in biofortification of wheat on calcareous soil: an isotopic study

Selenium (Se) biofortification of staple cereal crops can improve the Se nutritional status of populations. A field trial employing an enriched stable isotope of Se (⁷⁷Se) was undertaken over three consecutive cropping seasons in a coarse-textured, calcareous soil in Gilgit-Baltistan, Pakistan. The objectives were to (1) assess the feasibility and efficiency of Se biofortification, (2) determine the fate of residual Se, and (3) assess the consequences for dietary Se intake. Isotopically enriched ⁷⁷Se (⁷⁷Se_Fert) was applied, either as selenate or as selenite, at three levels (0, 10, and 20 g ha^?1) to a wheat crop. Residual ⁷⁷Se_Fert availability was assessed in subsequent crops of maize and wheat without further ⁷⁷Se_Fert addition. Loss of ⁷⁷Se_Fert was c.35% by the first (wheat) harvest, for both selenium species, attributable to the practice of flood irrigation and low adsorption capacity of the soil. No ⁷⁷Se_Fert was detectable in subsequent maize or wheat crops. The remaining ⁷⁷Se_Fert in soil was almost entirely organically bound and diminished with time following a reversible (pseudo-)first-order trend. Thus, repeat applications of Se would be required to adequately biofortify grain each year. In contrast to native soil Se, there was no transfer of ⁷⁷Se_Fert to a recalcitrant form. Grain from control plots would provide only 0.5 µg person^?1 day^?1 of Se. By contrast, a single application of 20 g ha^?1 Se^VI could provide c. 47 µg person^?1 day^?1 Se in wheat, sufficient to avoid deficiency when combined with dietary Se intake from other sources (c. 25 µg day^?1).

     

A passive sampler for hydrogen sulfide

The silver nitrate/fluorescein mercuric acetate fluorimetric method for the measurement of atmospheric hydrogen sulfide has been adapted to passive sampling. Standard samplers have been tested and used in both indoor and outdoor environments. Sampler performance was not dependent on construction materials or sunlight intensity and gave similar results to active sampling. Two case studies were carried out, one in the Horniman Museum and its associated storage and study building, London, UK, and the other in the vicinity of a pulp and paper mill and geothermal area North Island, New Zealand. The detection limit of the samplers (50 ppt average for a one-week exposure) provides the opportunity to make measurements in a variety of locations provided exposure times are sufficiently long, i.e., up to one month in areas of low hydrogen sulfide concentration.     

Herbicide loading to shallow ground water beneath Nebraska's Management Systems Evaluation Area

Better management practices can counter deterioration of ground water quality. From 1991 through 1996 the influence of improved irrigation practices on ground water pesticide contamination was assessed at the Nebraska Management Systems Evaluation Area. Three 13.4-ha corn (Zea mays L.) fields were studied: a conventional furrow-irrigated field, a surge-irrigated field and a center pivot-irrigated field, and a center pivot-irrigated alfalfa (Medicago sativa L.) field. The corn fields received one identical banded application of Bicep (atrazine [6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4,-diamine] + metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamidel) annually; the alfalfa field was untreated. Ground water samples were collected three times annually from 16 depths of 31 multilevel samplers. Six years of sample data indicated that a greater than 50% reduction in irrigation water on the corn management fields lowered average atrazine concentrations in the upper 1.5 m of the aquifer downgradient of the corn fields from approximately 5.5 to <0.5 microg L(-1). Increases in deethylatrazine (DEA; 2-chloro-4-amino-6-isopropylamino-s-triazine) to atrazine molar ratios indicated that reducing water applications enhanced microbial degradation of atrazine in soil zones. The occurrence of peak herbicide loading in ground water was unpredictable but usually was associated with heavy precipitation within days of herbicide application. Focused recharge of storm runoff that ponded in the surge-irrigated field drainage ditch, in the upgradient road ditch, and at the downgradient end of the conventionally irrigated field was a major mechanism for vertical transport. Sprinkler irrigation technology limited areas for focused recharge and promoted significantly more soil microbial degradation of atrazine than furrow irrigation techniques and, thereby, improved ground water quality.     

Phosphorus sorption by sediments in a southeastern coastal plain in-stream wetland

A close relationship has been reported between sediment organic C (SedOC) content and its P sorption capacity (P(max)) and total P (TP) concentration. Phosphorus sorbed to organically complexed cations is a proposed explanation for this relationship. The objectives of this study were (i) to determine relationships between in-stream wetland SedOC content and both the sediment's P(max) and TP concentrations, and (ii) to ascertain the role of both organically complexed and oxalate-extractable cations on the sediment P(max) and TP values. The sediment's oxalate-extractable Fe (Fe(ox)) and Al (Al(ox)) contents were determined using acidified ammonium oxalate, while sodium pyrophosphate was used to extract organically complexed cations (Al(pryo), Ca(pyro), Fe(pyro), Mg(pyro), and Mn(pyro)). Both the sediment's P(max) and TP contents were strongly correlated with its SedOC concentration (r(2) > 0.90, P < 0.001). Only the Al(ox) contents were significantly correlated with TP and P(max), suggesting that amorphous Al forms have an important role in P sorption. All five pyrophosphate-extracted cations were significantly correlated with SedOC contents. Regression analyses showed that the Al(pyro) accounted for 88% of the variation in sediment P(max) values, whereas a combination of Al(pyro) and Ca(pyro) accounted for 98% of the variation in sediment TP concentrations. Additionally, Al and Ca chelated by SedOC compounds also have an important role in P binding and indicate that a linkage exists between the wetlands SedOC and P(max) content and its ability to accumulate TP. This study identified that two different mechanisms have significant roles in regulating P sorption by sediments in a southeastern Coastal Plain in-stream wetland.     

Water quality parameters controlling the photodegradation of two herbicides in surface waters of the Columbia Basin,Washington

The water quality parameters nitrate-nitrogen, dissolved organic carbon, and suspended solids were correlated with photodegradation rates of the herbicides atrazine and 2,4-D in samples collected from four sites in the Columbia River Basin, Washington, USA. Surface water samples were collected in May, July, and October 2010 and analyzed for the water quality parameters. Photolysis rates for the two herbicides in the surface water samples were then evaluated under a xenon arc lamp. Photolysis rates of atrazine and 2,4-D were similar with rate constants averaging 0.025 h⁻¹ for atrazine and 0.039 h⁻¹ for 2,4-D. Based on multiple regression analysis, nitrate-nitrogen was the primary predictor of photolysis for both atrazine and 2,4-D, with dissolved organic carbon also a predictor for some sites. However, at sites where suspended solids concentrations were elevated, photolysis rates of the two herbicides were controlled by the suspended solids concentration. The results of this research provide a basis for evaluating and predicting herbicide photolysis rates in shallow surface waters.