Do feather-degrading bacteria affect sexually selected plumage color?

Models of parasite-mediated sexual selection propose that males with more elaborate sexual traits will have fewer parasites. These models have generally been tested using metazoan or protozoan parasites of the blood, gut, or integument. Fewer studies have examined sexual ornaments in relation to bacterial infections. While most surface bacteria are harmless or beneficial, feather-degrading bacteria may have detrimental effects. In this study, we examined the relationships between overall bacterial load, feather-degrading bacterial load, and sexually selected carotenoid-based plumage color in a wild population of house finches (Carpodacus mexicanus). We found that males with the redder plumage preferred by females had similar overall bacterial loads, but lower feather-degrading bacterial loads, than males with less red plumage. These data suggest that plumage color can signal abundance of feather-degrading bacteria to potential mates. It remains unclear whether feather-degrading bacteria directly or indirectly affect plumage color, but the observed correlations suggest that feather-degrading bacteria may play some role in sexual selection.     

Assessing links between crop diversity and food self-sufficiency in three agroecological regions of Nepal

Increasing on-farm crop diversity is one agroecological approach to enhancing food self-sufficiency that helps small-scale farmers keep their food systems stable by reducing risks associated with stressors, such as a pest outbreaks or droughts. But understanding how crop diversity and food self-sufficiency are related is unknown. To explore this complex relation, this study presents household data (n = 1664) from Nepal to test the hypothesis that families with high crop diversity enjoy greater household food self-sufficiency. Data are presented for three districts that are representative of three distinct agroecological regions of the country: (1) Sarlahi, which is affluent, market-oriented, and on the plains; (2) Makwanpur District in the hills, which has well-developed integrated farm production; and (3) the mountainous District of Humla, which has the poorest quality environment and is the most remote. Results show that in the Humla District, families with greater crop diversity were more self-sufficient. In contrast, farmers in Makwanpur, who have already established a high degree of crop diversity based on vegetable production, do not benefit from additional crop diversity in terms of their ability to provide for themselves. Finally, data from Sarlahi show that families’ food self-sufficiency benefits from crop diversification. We conclude that boosting crop diversity is a viable strategy for maintaining stability in food systems, but this varies depending on the accessibility of a farm and, in particular, access to markets.     

Sorption studies of heavy metal ions on a novel chelating resin and its application in the stripping of mercury (II)

A chelating resin containing a stable thiol group was synthesised, using polystyrene as the starting material. The resin is stable towards conc. HCl, 0.1M HNO(3) and 0.1M NaOH. The resin shows affinity towards Ag(+), Hg(2+), Bi(3+), Pb(2+), Cu(2+), Zn(2+) and Cd(2+). Extraction of these metal ions as a function of pH, kinetics of exchange and breakthrough capacities is evaluated. The selectivity of the resin for the metal ions is in the order Ag(+) > Hg2+ > Cu2+ > Pb2+ > Cd2+ > Zn2+. The equilibrium constants for exchange and kinetics of exchange are favourable for the recovery of mercury from lean sources. Application of the resin in the stripping of mercury from chlor-alkali plant affluent, and in the enrichment of mercury from seawater, have been investigated. Mercury sorbed resin can be regenerated using 5% thiourea in 0.1M HCl.     

Mesozooplankton distribution near an active volcanic island in the Andaman Sea (Barren Island)

The study addresses the distribution and diversity of mesozooplankton near the active volcano-Barren Island (Andaman Sea) in the context of persistent volcanic signature and warm air pool existing for the last few months. Sampling was done from the stations along the west and east side of the volcano up to a depth of 1,000 m during the inter monsoon (April) of 2006. Existence of feeble warm air pool was noticed around the Island (Atm. Temp. 29°C). Sea surface temperature recorded as 29.9°C on the west and 29.6°C on the east side stations. High mesozooplankton biomass was observed in the study area than the earlier reports. High density and biomass observed in the surface layer decreased significantly to the deeper depths. Lack of correlation was observed between mesozooplankton biomass and density with chl. a. Twenty-three mesozooplankton taxa were observed with copepoda as the dominant taxa followed by chaetognatha. The relative abundance of chaetognatha considerably affected the copepod population density in the surface layer. A noticeable feature was the presence of cumaceans, a hyperbenthic fauna in the surface, mixed layer and thermocline layer on the western side station where the volcano discharges in to the sea. The dominant order of copepoda, the calanoida was represented by 52 species belonging to 17 families. The order poecilostomatoida also had a significant contribution. Copepods exhibited a clear difference in their distribution pattern in different depth layers. The families Calanidae and Pontellidae showed a clear dominance in the surface whereas small-sized copepods belonging to the families Clausocalanidae and Paracalanidae were observed as the predominant community in the mixed layer and thermocline layer depth. Families Metridinidae, Augaptilidae and Aetideidae were observed as dominant in deeper layers.     

Development of new computational machine learning models for longitudinal dispersion coefficient determination: case study of natural streams,United States

Environmental Science and Pollution Research - Natural streams longitudinal dispersion coefficient (Kx) is an essential indicator for pollutants transport and its determination is very important....     

Population exposure to airborne thorium at the high natural radiation areas in India

High natural radiation areas in the coastal and peninsular India were studied for airborne thorium and resultant population exposure due to inhalation. Four locations covering three states viz., Ayiramthengu and Neendakara in Kerala, Kudiraimozhi in Tamil Nadu and Bhimilipatnam in Andhra Pradesh were investigated. External gamma radiation fields 1 m above the monazite ore bodies ranged from 200 to 3000 nGy h^-1. Soil samples showed ²³²Th specific activity varying from 0·1 to 1·5 Bq g^-1 with surface alpha activity in the range of 1·0–12·5 Bq cm^-2. Suspended particulates in the samples ranged from 60–140 μg m^-3 with ²³²Th showing a wider variation of <0·03–0·3 mBq m^-3. There was poor correlation between suspended particulates and long-lived alpha airborne activity . The resuspension factors for ²³²Th were in the range of 1·5×10^-8–7·9×10^-7 cm^-1. Higher resuspension was correlated with dry sand dunes. The upper limits for Committed Effective Dose (CED) due to inhalation of airborne ²³²Th at the respective high natural radiation areas were estimated to range from 50±30 to 300±130 μSv (5–30 mrem) per year per adult member of public assuming an activity median aerodynamic diameter of 1 μm for the airborne particulates.     

Response of embryos of the sea urchin Strongylocentrotus purpuratus to aqueous petroleum waste includes the expression of a high molecular weight glycoprotein

The present study investigated the sublethal effects of the largest aqueous waste associated with offshore oil development, produced water (PW), on sea urchin embryo development. PW inhibited normal gastrulation in purple sea urchin (Strongylocentrotus purpuratus) embryos exposed at the hatching stage. The exposed embryos did not form complete archenterons, and secondary mesenchyme cells exhibited an unusual behavior with respect to the wall of the blastocoelic cavity. In addition, an abundance of extracellular matrix was observed in the blastocoelic cavities in the embryos exposed to higher concentrations of PW. An inhibition of the development of embryos through the pluteus stage was observed as a result of PW exposure. This was manifested by inhibition of normal spicule formation with concomitant abnormal pluteus morphology. To determine if a biochemical stress response occurs as a result of PW exposure, embryos at the early gastrula stage were exposed to PW for 2 h, followed by an additional 1 h in 3H-leucine and PW. These embryos expressed a 253 kDa protein as observed by one-dimensional SDS (sodium dodecyl sulfate) polyacrylamide gel electrophoresis and autoradiography. This protein could occasionally be observed in gels stained for protein, and was glycosylated as demonstrated by staining with periodic acid Schiff (PAS). The 70 to 73 kDa heat-shock proteins previously described in sea urchin embryos (and other organisms) as a result of stress were not synthesized as a result of PW exposure. Heat shock did not induce synthesis of the 253 kDa glycoprotein. Combined PW and heat-shock exposure elicited both the heat-shock response (73 kDa protein) as well as expression of the 253 kDa glycoprotein. These data demonstrate the use of expression of endogenous macromolecular markers to distinguish exposures of embryos to different perturbations. Arsenic (as sodium arsenite), a metal constituent of PW, also induced the 253 kDa glycoprotein in early gastrula-stage embryos. We suggest that this glycoprotein may be a marker for PW (and a metal constituent) exposure in sea urchin embryos, and may be related to morphological abnormalities.     

Chemical composition of fresh snow from Gulmarg, North India

The chemical composition and pH of 30 fresh snow samples collected during December 1986 to May 1987 at Gulmarg (34 degrees 03' N, 74 degrees 24' E, 2655 m above mean sea level), a remote place in north India, were studied. The snow samples were, by and large, alkaline in nature and were largely influenced by non-marine aerosols. The concentrations of cations (Ca(2+), K(+) and Mg(2+)) were more than the anions (SO(2-)(4) and NO(-)(3)). Factor analysis indicated that most of the ionic components were transported into the region during the period of measurements. The transport of ionic components could be attributed to the passage of western disturbances over this region. The comparison of concentrations of anions and cations in the snow samples at Gulmarg with those reported from a few countries in the west revealed that the composition of Gulmarg snow largely differs in the concentrations of cations rather than anions. Among the cations, the concentration of Ca(2+) was high at Gulmarg and this could be responsible for buffering the pH of snow in the alkaline range.