Oregon State University

About: Oregon State University is a education organization based out in Corvallis, Oregon, United States. It is known for research contribution in the topics: Population & Gene. The organization has 28192 authors who have published 64044 publications receiving 2634108 citations. The organization is also known as: Oregon Agricultural College & OSU.

Quantitative determination of perfluorochemicals in sediments and domestic sludge.

Abstract: Perfluorochemicals (PFCs) are the subject of increasingly intense environmental research. Despite their detection both in biota and in aqueous systems, little attention has been paid to the possible presence of this class of compounds in solid environmental matrixes. The limited available data indicate that some PFCs such as perfluorooctane sulfonate (PFOS) may strongly sorb to solids, and sewage sludge is widely suspected as a major sink of PFCs entering municipal waste streams. A quantitative analytical method was developed that consists of liquid solvent extraction of the analytes from sediments and sludge, cleanup via solid-phase extraction, and injection of the extracts with internal standards into a high-performance liquid chromatography (HPLC) system coupled to a tandem mass spectrometer (LC/MS/MS). The limits of detections of the method were analyte and matrix dependent, but ranged from 0.7 to 2.2 ng/g and 0.041 to 0.246 ng/g (dry weight) for sludge and sediment, respectively. A demonstration of t...

Genome-Wide Profiling and Analysis of Arabidopsis siRNAs

Abstract: Eukaryotes contain a diversified set of small RNA-guided pathways that control genes, repeated sequences, and viruses at the transcriptional and posttranscriptional levels. Genome-wide profiles and analyses of small RNAs, particularly the large class of 24-nucleotide (nt) short interfering RNAs (siRNAs), were done for wild-type Arabidopsis thaliana and silencing pathway mutants with defects in three RNA-dependent RNA polymerase (RDR) and four Dicer-like (DCL) genes. The profiling involved direct analysis using a multiplexed, parallel-sequencing strategy. Small RNA-generating loci, especially those producing predominantly 24-nt siRNAs, were found to be highly correlated with repetitive elements across the genome. These were found to be largely RDR2- and DCL3-dependent, although alternative DCL activities were detected on a widespread level in the absence of DCL3. In contrast, no evidence for RDR2-alternative activities was detected. Analysis of RDR2- and DCL3-dependent small RNA accumulation patterns in and around protein-coding genes revealed that upstream gene regulatory sequences systematically lack siRNA-generating activities. Further, expression profiling suggested that relatively few genes, proximal to abundant 24-nt siRNAs, are regulated directly by RDR2- and DCL3-dependent silencing. We conclude that the widespread accumulation patterns for RDR2- and DCL3-dependent siRNAs throughout the Arabidopsis genome largely reflect mechanisms to silence highly repeated sequences.

Meltwater Pulse 1A from Antarctica as a Trigger of the Bølling-Allerød Warm Interval

Abstract: Meltwater pulse 1A (mwp-1A) was a prominent feature of the last deglaciation, which led to a sea-level rise of approximately 20 meters in less than 500 years. Concurrent with mwp-1A was the onset of the Bolling-Allerod interstadial event (14,600 years before the present), which marked the termination of the last glacial period. Previous studies have been unable to reconcile a warm Northern Hemisphere with mwp-1A originating from the Laurentide or Fennoscandian ice sheets. With the use of a climate model of intermediate complexity, we demonstrate that with mwp-1A originating from the Antarctic Ice Sheet, consistent with recent sea-level fingerprinting inferences, the strength of North Atlantic Deep Water (NADW) formation increases, thereby warming the North Atlantic region and providing an explanation for the onset of the Bolling-Allerod warm interval. The established mode of active NADW formation is then able to respond to subsequent freshwater forcing from the Laurentide and Fennoscandian ice sheets, setting the stage for the Younger Dryas cold period.

Amenity migration: diverse conceptualizations of drivers, socioeconomic dimensions, and emerging challenges

Abstract: Rural communities throughout the postindustrial world are in the midst of a significant transition, sometimes referred to as rural restructuring, as traditional land uses, economic activities, and social arrangements transition to those associated with “post-productivist” or “multifunctional” landscapes. Amenity migration, the movement of people based on the draw of natural and/or cultural amenities, can be thought of as both driver and implication of this transition, resulting in significant changes in the ownership, use, and governance of rural lands, as well as in the composition and socioeconomic dynamics of rural communities. In concert with other social, economic and political processes, amenity migration is contributing to the fundamental transformation of rural communities throughout the world. This paper presents a review of the social science literature related to the concept of amenity migration, focusing on the ways in which it has been conceptualized, theorized, and documented by different communities of scholars. We then profile and summarize diverse perspectives on drivers and socioeconomic impacts, highlighting emerging challenges and opportunities related to this type of migration occurring at multiple scales and in multiple sites. The paper also identifies and discusses particular areas where further research is needed.