4,535 research outputs found
Sedimentation in an artificial lake -Lake Matahina, Bay of Plenty
Lake Matahina, an 8 km long hydroelectric storage reservoir, is a small (2.5 km2), 50 m deep, warm monomictic, gorge-type lake whose internal circulation is controlled by the inflowing Rangitaiki River which drains a greywacke and acid volcanic catchment. Three major proximal to distal subenvironments are defined for the lake on the basis of surficial sediment character and dominant depositional process: (a) fluvial-glassy, quartzofeld-spathic, and lithic gravel-sand mixtures deposited from contact and saltation loads in less than 3 m depth; (b) (pro-)deltaic-quartzofeldspathic and glassy sand-silt mixtures deposited from graded and uniform suspension loads in 3-20 m depth; and (c) basinal-diatomaceous, argillaceous, and glassy silt-clay mixtures deposited from uniform and pelagic suspension loads in 20-50 m depth. The delta face has been prograding into the lake at a rate of 35-40 m/year and vertical accretion rates in pro-delta areas are 15-20 cm/year. Basinal deposits are fed mainly from river plume dispersion involving overflows, interflows, and underflows, and by pelagic settling, and sedimentation rates behind the dam have averaged about 2 cm/year. Occasional fine sand layers in muds of basinal cores attest to density currents or underflows generated during river flooding flowing the length of the lake along a sublacustrine channel marking the position of the now submerged channel of the Rangitaiki River
Proteomic analysis of E. coli using 2D HPLC and MALDI-TOF mass spectrometry
Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Includes bibliographical references (leaves 12-13).In this post-genomic era, researchers are striving to find new ways to use the enormous amounts of data that have been collected. One obvious way is with proteomics, the large-scale identification of expressed proteins. We have developed a novel method for identifying proteins using two dimensions of non-denaturing high performance liquid chromatography (HPLC) and matrix assisted laser desorption ionization time of flight (MALDI-TOF) mass spectrometry. The first dimension of separation uses an anion exchange column and each of those fractions is run through the second dimension, a hydrophobic interaction column. The proteins were then dialyzed, denatured, and digested with trypsin before being subjected to mass spectrometry. Identifications were made based on the peptide masses. Using this method we have made 2012 protein identifications, 310 of which are unique. These numbers are comparable to other forms of proteomics such as 2-D gels
Collaborative Research: Gymnosperms on the Tree of Life: Resolving the Phylogeny of Seed Plants
An award is made to Sarah Mathews (Lead PI), Jianhua Li (Co-PI), Harvard University; Reed S. Beaman (PI), Nico Cellinese (Co-PI), Yale University; Christopher S. Campbell (PI), University of Maine; Richard C. Cronn (Collaborator), USDA Forest Service; Sean W. Graham (Co-PI), University of British Columbia; Stefanie M. Ickert-Bond (PI), University of Alaska; Dean G. Kelch (PI), University of California-Berkeley and California State Herbarium; Aaron I. Liston (PI), Oregon State University; Linda A. Raubeson (PI), Central Washington University; Gar W. Rothwell (PI), Gene Mapes (Co-PI), Ohio University; Andrea E. Schwarzbach (PI), University of Texas-Brownsville; Dennis W. Stevenson (PI), New York Botanical Garden; Ruth A. Stockey (Co-PI), University of Alberta to construct sequence-based phylogenetic hypotheses for all living gymnosperms and for seed plants overall, and morphology-based hypotheses to include ALL living species of gymnosperms (conifers, cycads, Gingko, and Gnetales) including examples from the fossil record, along with exemplar angiosperms (flowering plants). Nuclear, plastid and mitochondrial sequences will be utilized in the analysis along with the morphological characters to allow the rich record of fossil gymnosperms to be included. All of the data (molecular, morphological, voucher, etc.) will be submitted to standardized and accessible databases through an enhanced version of the web-based informatics tool TOLKIN (Tree Of Life Knowledge and Information Network, www.tolkin.org). The evolution of the seed marks one of the most important innovations in the history of land plants and led to greater mating control and to enhanced survival and dispersal capabilities. Seed bearing plants dominate the landscape; today, forests and grasslands are among our most important resources. Understanding the origin(s) of seeds is basic to understanding seed plant phylogeny. Obtaining the needed phylogenetic framework is not a trivial undertaking and the multi-faceted approach is designed to address the inherent complexity of the problem, incorporating approaches not considered by all projects (e.g., including all gymnosperms, serious attention to the fossil data). While phylogenetic inference will be the main focus of the project, data will bear significantly on the understanding of historic patterns of biotic change at the global level, and will provide insight into the origins of many important plant traits, including those that are the basis of breeding programs in horticulture and forestry. In addition to training students, workshops for K-12 teachers will be held at several botanic gardens
Molecular Phylogenetic Studies in Rosaceae
This project will investigate the evolutionary relationships within the large and important rose family. This group of plants contains numerous commercially valuable fruits (apples, pears, strawberries, cherries, peaches, plums, blackberries, and raspberries) and many horticulturally significant plants (roses, cotoneaster, lady\u27s mantle, bridle-wreath, flowering quince, fire-thorn, cinqfoil, and others). Despite the large and important role that these plants play in our daily lives and scientific interest, we do not have a clear view of the evolutionary relationships of members of the family. A primary reason for this situation is that insufficient evidence has been accumulated to adequately address the problem. A primary aim of Dr. Campbell\u27s project is to gather DNA sequence data to provide a reliable chronicle of evolutionary history in this group. These data will be compared with structural, chemical, and other data that have been accumulated by Dr. Campbell and other researchers to create an overall picture of evolutionary relationships in the family. Such knowledge will establish a framework for studies of key groups within the family, provide insights into the evolution of interesting features in the family (such as the fruits), and contribute to our overall understanding or plant evolution
REVSYS: Systematics of Amelanchier (Rosaceae)
Amelanchier contains about 20 species of trees and shrubs of the North Temperate Zone. These plants bear attractive flowers, their fruits are important to wildlife, and they are valued horticulturally. Shadbushes and serviceberries, as these plants are commonly called, are native to every state of the United States except Hawaii. It has been a challenge to define the species of Amelanchier because hybridization is frequent, and novel kinds of plants created by hybridization can be widely dispersed. Some forms of shadbushes are easy to distinguish while others differ from one another in minute ways. The goal of this research is to define species in this genus based on extensive field and laboratory data. This research will provide a new classification of species in an ecologically important group of plants. Results will be disseminated in the scientific literature and on our web site (http://biology.umaine.edu/Amelanchier/) for botanists, horticulturists, wildlife ecologists, conservation biologists, land-use managers, and others. Training of undergraduate and graduate students in plant systematics (classification) is essential to maintaining our capacity to understand and communicate about plant species. This research will provide outreach through workshops to give K-12 teachers exercises in pollination biology for their students
Mlh2 is an accessory factor for DNA mismatch repair in Saccharomyces cerevisiae.
In Saccharomyces cerevisiae, the essential mismatch repair (MMR) endonuclease Mlh1-Pms1 forms foci promoted by Msh2-Msh6 or Msh2-Msh3 in response to mispaired bases. Here we analyzed the Mlh1-Mlh2 complex, whose role in MMR has been unclear. Mlh1-Mlh2 formed foci that often colocalized with and had a longer lifetime than Mlh1-Pms1 foci. Mlh1-Mlh2 foci were similar to Mlh1-Pms1 foci: they required mispair recognition by Msh2-Msh6, increased in response to increased mispairs or downstream defects in MMR, and formed after induction of DNA damage by phleomycin but not double-stranded breaks by I-SceI. Mlh1-Mlh2 could be recruited to mispair-containing DNA in vitro by either Msh2-Msh6 or Msh2-Msh3. Deletion of MLH2 caused a synergistic increase in mutation rate in combination with deletion of MSH6 or reduced expression of Pms1. Phylogenetic analysis demonstrated that the S. cerevisiae Mlh2 protein and the mammalian PMS1 protein are homologs. These results support a hypothesis that Mlh1-Mlh2 is a non-essential accessory factor that acts to enhance the activity of Mlh1-Pms1
TB99: Flora of Oxford County, Maine
This is a study of the vascular plants occurring in Oxford County, Maine. Plants with vascular or conductive tissue (kingdom Plantae, division Tracheophyta) include the ferns and their allies (horsetails and lycopods) and the seed-bearing plants. Our aim has been to determine which plants occur in the county and, based on herbarium collections and observations, their habitat preferences, frequency of occurrence, and geographic distribution. We have also endeavored to explain the nature of the flora first in terms of the various factors which influence its composition and second by grouping the plants into the most important natural associations.https://digitalcommons.library.umaine.edu/aes_techbulletin/1106/thumbnail.jp
Association is not causation: treatment effects cannot be estimated from observational data in heart failure
Aims:
Treatment âeffectsâ are often inferred from non-randomized and observational studies. These studies have inherent biases and limitations, which may make therapeutic inferences based on their results unreliable. We compared the conflicting findings of these studies to those of prospective randomized controlled trials (RCTs) in relation to pharmacological treatments for heart failure (HF).
Methods and results:
We searched Medline and Embase to identify studies of the association between non-randomized drug therapy and all-cause mortality in patients with HF until 31 December 2017. The treatments of interest were: angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, beta-blockers, mineralocorticoid receptor antagonists (MRAs), statins, and digoxin. We compared the findings of these observational studies with those of relevant RCTs. We identified 92 publications, reporting 94 non-randomized studies, describing 158 estimates of the âeffectâ of the six treatments of interest on all-cause mortality, i.e. some studies examined more than one treatment and/or HF phenotype. These six treatments had been tested in 25 RCTs. For example, two pivotal RCTs showed that MRAs reduced mortality in patients with HF with reduced ejection fraction. However, only one of 12 non-randomized studies found that MRAs were of benefit, with 10 finding a neutral effect, and one a harmful effect.
Conclusion:
This comprehensive comparison of studies of non-randomized data with the findings of RCTs in HF shows that it is not possible to make reliable therapeutic inferences from observational associations. While trials undoubtedly leave gaps in evidence and enrol selected participants, they clearly remain the best guide to the treatment of patients
Key Points in Preparation for Oregon Legislative Session (2024): Examining the Multifaceted Impacts of Drug Decriminalization on Public Safety, Law Enforcement, and Prosecutorial Discretion
These findings are part of a 3-year study to examine the impacts of possession of PCS law changes on: (1) law enforcement discretion, (2) prosecutorial decision-making, (3) courts/sentencing, and (4) public safety. The key findings, unless noted, represent statewide trends and impacts. Prior to M110, other statewide changes in policy, law, and historical events such as the COVID-19 lockdown/court backlog and public defense crisis also had important impacts on enforcement, prosecution/sentencing, and public safety outcomes. As such, data collected during the early implementation of M110 is not likely a reliable predictor of its ultimate impact. The data reported on below is through 1 â 2 years post-M110. Although it sheds light on important questions, it is too early to draw any definitive conclusions about long-term impacts of M110. Link to Year One Report: https://archives.pdx.edu/ds/psu/4011
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