A 5-micron-bright spot on Titan: evidence for surface diversity

Observations from the Cassini Visual and Infrared Mapping Spectrometer show an anomalously bright spot on Titan located at 80 degrees W and 20 degrees S. This area is bright in reflected light at all observed wavelengths, but is most noticeable at 5 microns. The spot is associated with a surface albedo feature identified in images taken by the Cassini Imaging Science Subsystem. We discuss various hypotheses about the source of the spot, reaching the conclusion that the spot is probably due to variation in surface composition, perhaps associated with recent geophysical phenomena.     

Preliminary meteorological results on Mars from the viking 1 lander

The results from the meteorology instruments on the Viking 1 lander are presented for the first 4 sols of operation. The instruments are working satisfactorily. Temperatures fluctuated from a low of 188 degrees K to an estimated maximum of 244 degrees K. The mean pressure is 7.65 millibars with a diurnal variation of amplitude 0.1 millibar. Wind speeds averaged over several minutes have ranged from essentially calm to 9 meters per second. Wind directions have exhibited a remarkable regularity which may be associated with nocturnal downslope winds and gravitational oscillations, or to tidal effects of the diurnal pressure wave, or to both.     

Plasma levels of cortisol and corticosteroid-binding globulin (CBG) and hepatic CBG mRNA expression in pre- and postnatal pigs

The relationships among hepatic corticosteroid-binding globulin (CBG) mRNA expression and plasma concentrations of cortisol and CBG was evaluated in fetal pigs (n=7-14 per age) on days 50, 70, 80, 90, and 104 of gestation and postnatal pigs (n=8 per age) on days 1, 3, 10, 20, 30, and 40 following birth. In fetal pigs, hepatic CBG mRNA expression was highest (P<0.01) on day 50 as compared to days 90 and 104, exhibiting an overall negative relationship (r=-0.63; P<0.01) with estimated gestation age. Plasma porcine CBG (pCBG) concentration was correlated (r=0.34; P<0.05) with hepatic CBG mRNA level. Plasma cortisol concentrations were not different over this same period. In postnatal pigs, hepatic CBG mRNA expression increased (P<0.01) from days 3 to 40. The pCBG concentration increased (P<0.01) from days 1 (6.1+/-3.4 microg/ml) to 10 (15.1+/-3.7 microg/ml), while plasma cortisol concentration remained constant. An understanding of the relation between hepatic CBG mRNA and circulating pCBG concentrations may provide insight into the mechanisms determining the bioavailability of cortisol necessary in prenatal development and the conservation of cortisol during postnatal development in the pig.     

Can waterbirds with different movement,dietary and foraging functional traits occupy similar ecological niches?

Context

Competitive interactions potentially play an important role in structuring bird communities. It is unclear how differences in functional traits influence the niche dimensions of highly mobile waterbird species, particularly when they co-exist in spatiotemporally heterogeneous communities.

Objectives

We investigated the inter-relationships between waterbird trait groupings (movement, dietary and foraging habitat) and environmental variable groupings (rainfall, land cover, vegetation structure and water quality). Specifically, we tested whether the scale of environmental variables filtered movement traits and whether these traits operated in conjunction with dietary and foraging habitat traits to form distinct ecological niches in waterbirds.

Methods

We conducted waterbird and environmental variable surveys in 60 sites, sampled seven times each at bimonthly intervals, in KwaZulu-Natal, South Africa. Trait-environment relationships were tested using a combination of RLQ and fourth-corner analyses.

Results

Several significant trait-environment relationships emerged in bivariate correlations and multivariate ordination space. Movement traits correlated with the scale of environmental variables; migrant and nomadic species responded to broad scale environmental variables. Vegetation structure and land cover were particularly important in explaining the abundance of species foraging in emergent vegetation. Three groups emerged along a gradient in multivariate ordination space providing evidence for ecological niche separation of waterbirds with different movement traits.

Conclusions

Our findings suggest that the scale of landscape resources can act as a filter of movement traits, and that in conjunction with dietary and foraging traits, waterbirds with different movement traits occupy distinct ecological niches.

     

Molecular and biological characterization of a naturally occurring recombinant subgroup B avian leukosis virus with a subgroup J-like long terminal repeat

Infection of broiler chickens with subgroup J avian leukosis virus (ALV) results in the induction of myeloid tumors. However, although egg-type chickens are susceptible to infection with ALV-J, the tumor incidence is very low, and on rare occasions the tumors observed are of the myeloid lineage. We recently described the isolation of an ALV (AF115-4) from commercial egg-type chickens suffering from myeloid leukosis. AF115-4 was initially identified as an ALV-J isolate based on PCR analysis of the long terminal repeat (LTR). However, further characterization of the viral envelope indicated that the virus is recombinant with subgroups B envelope and J LTR. Here we further characterize this recombinant virus at both the molecular and biological levels. We show that the AF115-4 isolate expresses a recombinant envelope glycoprotein encoded by a subgroup B gp85 region and a subgroup E gp37 region. The host range ofAF115-4 was analyzed using cells resistant to infection by subgroups A/B, J, or E; this shows that no ALV-J was present in the isolates obtained from the affected chickens. Additional antigenic characterization of AF115-4 using chicken sera specific for subgroups B or J indicated that no ALV-J was present in the samples examined. Inoculation of AF 115-4 into ALV-susceptible 1515 X 71 chickens resulted in the induction of lymphoid leukosis but not the expected myeloid leukosis affecting the commercial chickens. These results suggest that differences in the genetic makeup of the chickens from which AF115-4 was isolated and the line 1515 X 71 used in the present experiments may be responsible for the observed differences in pathogenicity. In addition, the results suggest that ALV-J continues to evolve by recombination, generating new viruses with different pathological properties.     

Field evaluation of reduced insecticide spray programs for managing plum curculio, Conotrachelus nenuphar (Coleoptera: Curculionidae), in Alabama peaches

BACKGROUND: Plum curculio (PC), Conotrachelus nenuphar (Herbst.), is an important pest of peaches in the southeastern United States. Commercially acceptable control of this insect is typically achieved by weekly or biweekly application of broad‐spectrum conventional insecticides, resulting in 6–12 sprays per season. Experiments were conducted in a peach orchard in Alabama during 2007–2009 to compare the conventional calendar‐based insecticide spray program involving weekly applications of phosmet with three different reduced spray programs using three targeted (well‐timed) insecticide sprays (TIS) of phosmet, permethrin or thiamethoxam applied in an alternated fashion. RESULTS: All three TIS programs significantly reduced PC damage at harvest compared with the untreated control in two of the three years (2008 and 2009). Fruit damage due to stink bugs, which are emerging pests of peaches in the region, was also significantly reduced in the TIS programs in both years. In a separate trial in which one of the TIS programs (three targeted sprays of phosmet) was evaluated in a larger peach block in 2009, percentage fruit damage due to PC increased from < 1% in June to ～4% in late July. CONCLUSION: All the TIS programs evaluated provided effective control of PC and represent potential alternatives to the conventional weekly spray program in peaches with concomitant reduction in insecticide usage and associated costs. However, an additional spray may be necessary for effective control of PC and stink bugs in late‐season peach varieties. Copyright © 2011 Society of Chemical Industry     

Genetic correlations among pulpwood and solid-wood selection traits in Eucalyptus globulus

New Forests - Eucalyptus globulus is widely grown for pulpwood production in temperate regions of the world. However, there is increasing interest in using it for solid-wood products. We studied...