University of Georgia

About: University of Georgia is a education organization based out in Athens, Georgia, United States. It is known for research contribution in the topics: Population & Gene. The organization has 41934 authors who have published 93622 publications receiving 3713212 citations. The organization is also known as: UGA & Franklin College.

Low symbiont diversity in southern Great Barrier Reef corals, relative to those of the Caribbean

Abstract: The specific identity of endosymbiotic dinoflagellates (Symbiodinium spp.) from most zooxanthellate corals is unknown. In a survey of symbiotic cnidarians from the southern Great Barrier Reef (GBR), 23 symbiont types were identified from 86 host species representing 40 genera. A majority (>85%) of these symbionts belong to a single phylogenetic clade or subgenus (C) composed of closely related (as assessed by sequence data from the internal transcribed spacer region and the ribosomal large subunit gene), yet ecologically and physiologically distinct, types. A few prevalent symbiont types, or generalists, dominate the coral community of the southern GBR, whereas many rare and/or specific symbionts, or specialists, are found uniquely within certain host taxa. The comparison of symbiont diversity between southern GBR and Caribbean reefs shows an inverse relationship between coral diversity and symbiont diversity, perhaps as a consequence of more-rapid diversification of Caribbean symbionts. Among clade C types, generalists C1 and C3 are common to both Caribbean and southern GBR symbiont assemblages, whereas the rest are regionally endemic. Possibly because of environmental changes in the Caribbean after geographic isolation through the Quaternary period, a high proportion of Caribbean fauna associate with symbiont taxa from two other distantly related Symbiodinium clades (A and B) that rarely occur in Pacific hosts. The resilience of Porites spp. and the resistance of Montipora digitata to thermal stress and bleaching are partially explained by their association with a thermally tolerant symbiont type, whereas the indiscriminant widespread bleaching and death among certain Pacific corals, during El Nino Southern Oscillation events, are influenced by associations with symbionts possessing higher sensitivity to thermal stress.

The stability of attachment security from infancy to adolescence and early adulthood: general introduction.

Abstract: Current attachment theory hypothesizes that attachment security during infancy influences individual differences in adult representations of attachment. We present three long-term longitudinal studies using three different samples relevant to this hypothesis. Each study assesses infant attachment by using the Ainsworth Strange Situation and adult attachment by using the Berkeley Adult Attachment Interview (AAI). Attachment security was significantly stable in the first two studies. Discontinuity in all three studies was related to negative life events and circumstances. Comparison of the results across these complementary studies affords a degree of replication and sheds light on alternative interpretations. Various mechanisms underlying the stability and instability of attachment security are discussed.

A micro‐pipette method for soil mechanical analysis

Abstract: Determination of soil texture, particularly the clay (<2 μm) fraction, is an important measurement in most soil investigations. In this study a modified method for mechanical analysis was evaluated that eliminated the need for bulky laboratory equipment and long settling times associated with standard pipette and hydrometer methods. Termed a “micro‐pipette”; method, the modified procedure uses 2 to 4 g soil with 40 mL of dilute dispersant, shaken overnight in 50 mL centrifuge tubes. Clay is determined by sampling 2.5 mL using an adjustable volume pipettor from a depth of 2.5 cm after approximately 2 h of settling, as calculated from Stokes’ law. The dried suspension weight is used to compute clay content after correction for salt content of the dispersant. Sand can be determined by sieving at 50 μm after clay analysis, with silt calculated by difference. Using 12 soils with a range of particle sizes, the proposed method was found to give textural values nearly identical to those found with the st...

U-Commerce: Expanding the Universe of Marketing

Abstract: This article introduces several new concepts that lay the conceptual foundation for thinking about next-generation marketing based on ubiquitous networks. U-commerce, orUber-commerce, is predicated on the characteristics of network ubiquity, universality, uniqueness, and unison. It is proposed that the keys to managing network-driven firms are the concepts of u-space and attention analysis. The implications for next-generation marketing in the u-space are explored, with a research agenda identified for scholars and managerial implications recognized for practitioners.

Bacterial Community Structure Associated with a Dimethylsulfoniopropionate-Producing North Atlantic Algal Bloom

Abstract: The bacteria associated with oceanic algal blooms are acknowledged to play important roles in carbon, nitrogen, and sulfur cycling, yet little information is available on their identities or phylogenetic affiliations. Three culture-independent methods were used to characterize bacteria from a dimethylsulfoniopropionate (DMSP)-producing algal bloom in the North Atlantic. Group-specific 16S rRNA-targeted oligonucleotides, 16S ribosomal DNA (rDNA) clone libraries, and terminal restriction fragment length polymorphism analysis all indicated that the marine Roseobacter lineage was numerically important in the heterotrophic bacterial community, averaging >20% of the 16S rDNA sampled. Two other groups of heterotrophic bacteria, the SAR86 and SAR11 clades, were also shown by the three 16S rRNA-based methods to be abundant in the bloom community. In surface waters, the Roseobacter, SAR86, and SAR11 lineages together accounted for over 50% of the bacterial rDNA and showed little spatial variability in abundance despite variations in the dominant algal species. Depth profiles indicated that Roseobacter phylotype abundance decreased with depth and was positively correlated with chlorophyll a, DMSP, and total organic sulfur (dimethyl sulfide plus DMSP plus dimethyl sulfoxide) concentrations. Based on these data and previous physiological studies of cultured Roseobacter strains, we hypothesize that this lineage plays a role in cycling organic sulfur compounds produced within the bloom. Three other abundant bacterial phylotypes (representing a cyanobacterium and two members of the α Proteobacteria) were primarily associated with chlorophyll-rich surface waters of the bloom (0 to 50 m), while two others (representing Cytophagales and δ Proteobacteria) were primarily found in deeper waters (200 to 500 m).