122 research outputs found
δ13C tracing of dissolved inorganic carbon sources in major world rivers
δ13C tracing of dissolved inorganic carbon sources in major world river
An integrative approach to understanding mussel community structure: Linking biodiversity, environmental context and physiology.
The focus of my third chapter is an integration of the physiology information collected in chapter two to address how species dominance of two distinct thermal guilds (thermally-tolerant and thermally-sensitive) influences gross primary production. I manipulated temperature (15, 25, and 35° C) and species dominance of five mussel species (A. ligamentina, A. plicata and Q. pustulosa, M. nervosa, and O. reflexa) using 1101 re-circulating stream mesocosms housed in an environmentally-controlled room. I quantified individual-based measures of resource acquisition (oxygen consumption, body condition index) and ecosystem services (ammonia and phosphorus excretion rates) for each species. In addition, I quantified gross primary production in the water column, benthos, and the entire stream mesocosm. Gross primary production was highest at 35° C and was positively related to both A. ligamentina and A. plicata dominance with communities. However, species dominance differentially influenced gross primary production of different compartments within the mesocosms with A. plicata (a thermally-tolerant species) positively influencing benthic production, and A. ligamentina (a thermally-sensitive species) positively influencing water column production. Species interactions within treatments were context dependent with A. ligamentina positively influencing A. plicata, M. nervosa, and O. reflexa at 25° C and negatively influencing M. nervosa and O. reflexa at 35° C. In addition to influencing resource acquisition, species dominance also influenced species-specific nutrient excretion rates and subsequently water-column nutrient levels.The research detailed in my second chapter built upon observed patterns of alternating species dominance by asking if different mussel species performed differently under a variety of thermal regimes. To address this question, I acclimated eight mussel species (Lampsilis cardium, Fusconaia flava, Actinonaias ligamentina, Megalonaias nervosa, Amblema plicata, Quadrula pustulosa, Obliquaria reflexa, and Truncilla truncata) to four temperatures (5, 15, 25, and 35° C). I quantified resource acquisition (clearance rate and oxygen consumption), assimilation (glycogen, body condition index, and Q10 rates of anabolism and catabolism), and ecosystem services (ammonia and phosphorus excretion rates, and biodeposition rates) using temperature-controlled respirometers. The results of this experiment demonstrate that although mussels are generally categorized as "filter feeders", there are distinct guilds within this functional group associated with their response to temperature. Megalonaias nervosa, Amblema plicata, Obliquaria reflexa, and Fusconaia flava are thermally-tolerant species assimilating energy at 35° C and increasing the magnitude of services (nutrient excretion, clearance and biodeposition rates) they contribute to ecosystems. Alternatively, A. ligamentina, L. cardium, Q. pustulosa , and Truncilla truncata appear to be thermally-sensitive with increased rates of catabolism at 35° C. However, the functional responses of thermally-sensitive species appeared to differ with some species decreasing filtration activity and increasing rates of nutrient excretion and others increasing both filtration and nutrient excretion rates. Extrapolating these data to real mussel communities highlighted the importance of the relative dominance between thermally-sensitive and tolerant-species under differing environmental contexts. Furthermore, shifts in community structure would be predicted to influence the nature of filtration, biodeposition and nutrient dynamics under current models of climate change.My first chapter integrated biodiversity partitioning techniques with mussel community data across twenty one mussel beds to determine if mussel community biomass could be explained by patterns of species richness or species dominance. This partitioning approach tested the null hypothesis that biomass accrual within mussel beds is equal at all sites. The results of this work demonstrated that mussel biomass is largely explained by complementarity, which indicates that either niche partitioning or facilitation between mussel species is occurring. This conclusion was further supported by the fact that complementarity was highest in species rich, thermally variable mussel beds. In addition, numerically rarer species were in better condition (reduced oxygen consumption rates and higher body condition indices) in species-rich, thermally variable mussel beds which suggests that there is an energetic benefit to living in species rich communities.The research detailed in my dissertation broadens our understanding of the biodiversity-ecosystem function paradigm using long-lived invertebrates in a freshwater ecosystem. Freshwater mussels (Unionoidea) are a globally threatened fauna with 70% of taxa considered threatened, yet little is known concerning their functional role. In addition to species extinctions, the overall biomass of both abundant and rare unionid species is declining in most rivers, and this loss of filter-feeding biomass is predicted to impact river function
759–5 Use of an Interactive Electronic Whiteboard to Teach Clinical Cardiology Decision Analysis to Medical Students
We used innovative state-of-the-art computer and collaboration technologies to teach first-year medical students an analytic methodology to solve difficult clinical cardiology problems to make informed medical decisions. Clinical examples included the decision to administer thrombolytic therapy considering the risk of hemorrhagic stroke, and activity recommendations for athletes at risk for sudden death. Students received instruction on the decision-analytic approach which integrates pathophysiology, treatment efficacy, diagnostic test interpretation, health outcomes, patient preferences, and cost-effectiveness into a decision-analytic model.The traditional environment of a small group and blackboard was significantly enhanced by using an electronic whiteboard, the Xerox LiveBoard™. The LiveBoard features an 80486-based personal computer, large (3’×4’) display, and wireless pens for input. It allowed the integration of decision-analytic software, statistical software, digital slides, and additional media. We developed TIDAL (Team Interactive Decision Analysis in the Large-screen environment), a software package to interactively construct decision trees, calculate expected utilities, and perform one- and two-way sensitivity analyses using pen and gesture inputs. The Live Board also allowed the novel incorporation of Gambler, a utility assessment program obtained from the New England Medical Center. Gambler was used to obtain utilities for outcomes such as non-disabling hemorrhagic stroke. The interactive nature of the LiveBoard allowed real-time decision model development by the class, followed by instantaneous calculation of expected utilities and sensitivity analyses. The multimedia aspect and interactivity were conducive to extensive class participation.Ten out of eleven students wanted decision-analytic software available for use during their clinical years and all students would recommend the course to next year's students. We plan to experiment with the electronic collaboration features of this technology and allow groups separated by time or space to collaborate on decisions and explore the models created
A human embryonic kidney 293T cell line mutated at the Golgi -mannosidase II locus
Disruption of Golgi -mannosidase II activity can result in type II congenital dyserythropoietic anemia and can induce lupus-like autoimmunity in mice. Here, we isolate a mutant human embryonic kidney (HEK) 293T cell line, called Lec36, that displays sensitivity to ricin that lies between the parental HEK 293T cells, whose secreted and membrane-expressed proteins are dominated by complex-type glycosylation, and 293S Lec1 cells, which only produce oligomannose-type N-linked glycans. The stem cell marker, 19A, was transiently expressed in the HEK 293T Lec36 cells, and in parental HEK 293T cells with and without the potent Golgi -mannosidase II inhibitor, swainsonine. Negative-ion nano-electrospray ionization mass spectra of the 19A N-linked glycans from HEK 293T Lec36 and swainsonine-treated HEK 293T cells were qualitatively indistinguishable and, as shown by collision-induced dissociation spectra, dominated by hybrid-type glycosylation. Nucleotide sequencing revealed mutations in each allele of MAN2A1, the gene encoding Golgi -mannosidase II: a point mutation in one allele mapping to the active site and an in-frame deletion of twelve-nucleotides in the other. Expression of wild-type but not the mutant MAN2A1 alleles in Lec36 cells restored processing of the 19A reporter glycoprotein to complex-type glycosylation. The Lec36 cell line will be useful for expressing therapeutic glycoproteins with hybrid-type glycans and provides a sensitive host for detecting mutations in human MAN2A1 causing type II congenital dyserythropoietic anemia
Gramene: a bird's eye view of cereal genomes
Rice, maize, sorghum, wheat, barley and the other major crop grasses from the family Poaceae (Gramineae) are mankind's most important source of calories and contribute tens of billions of dollars annually to the world economy (FAO 1999, ; USDA 1997, ). Continued improvement of Poaceae crops is necessary in order to continue to feed an ever-growing world population. However, of the major crop grasses, only rice (Oryza sativa), with a compact genome of ∼400 Mbp, has been sequenced and annotated. The Gramene database () takes advantage of the known genetic colinearity (synteny) between rice and the major crop plant genomes to provide maize, sorghum, millet, wheat, oat and barley researchers with the benefits of an annotated genome years before their own species are sequenced. Gramene is a one stop portal for finding curated literature, genetic and genomic datasets related to maps, markers, genes, genomes and quantitative trait loci. The addition of several new tools to Gramene has greatly facilitated the potential for comparative analysis among the grasses and contributes to our understanding of the anatomy, development, environmental responses and the factors influencing agronomic performance of cereal crops. Since the last publication on Gramene database by D. H. Ware, P. Jaiswal, J. Ni, I. V. Yap, X. Pan, K. Y. Clark, L. Teytelman, S. C. Schmidt, W. Zhao, K. Chang et al. [(2002), Plant Physiol., 130, 1606–1613], the database has undergone extensive changes that are described in this publication
Gramene: a bird's eye view of cereal genomes
Rice, maize, sorghum, wheat, barley and the other major crop grasses from the family Poaceae (Gramineae) are mankind's most important source of calories and contribute tens of billions of dollars annually to the world economy (FAO 1999, ; USDA 1997, ). Continued improvement of Poaceae crops is necessary in order to continue to feed an ever-growing world population. However, of the major crop grasses, only rice (Oryza sativa), with a compact genome of ∼400 Mbp, has been sequenced and annotated. The Gramene database () takes advantage of the known genetic colinearity (synteny) between rice and the major crop plant genomes to provide maize, sorghum, millet, wheat, oat and barley researchers with the benefits of an annotated genome years before their own species are sequenced. Gramene is a one stop portal for finding curated literature, genetic and genomic datasets related to maps, markers, genes, genomes and quantitative trait loci. The addition of several new tools to Gramene has greatly facilitated the potential for comparative analysis among the grasses and contributes to our understanding of the anatomy, development, environmental responses and the factors influencing agronomic performance of cereal crops. Since the last publication on Gramene database by D. H. Ware, P. Jaiswal, J. Ni, I. V. Yap, X. Pan, K. Y. Clark, L. Teytelman, S. C. Schmidt, W. Zhao, K. Chang et al. [(2002), Plant Physiol., 130, 1606–1613], the database has undergone extensive changes that are described in this publication
Gramene: a bird's eye view of cereal genomes
Rice, maize, sorghum, wheat, barley and the other major crop grasses from the family Poaceae (Gramineae) are mankind's most important source of calories and contribute tens of billions of dollars annually to the world economy (FAO 1999, ; USDA 1997, ). Continued improvement of Poaceae crops is necessary in order to continue to feed an ever-growing world population. However, of the major crop grasses, only rice (Oryza sativa), with a compact genome of ∼400 Mbp, has been sequenced and annotated. The Gramene database () takes advantage of the known genetic colinearity (synteny) between rice and the major crop plant genomes to provide maize, sorghum, millet, wheat, oat and barley researchers with the benefits of an annotated genome years before their own species are sequenced. Gramene is a one stop portal for finding curated literature, genetic and genomic datasets related to maps, markers, genes, genomes and quantitative trait loci. The addition of several new tools to Gramene has greatly facilitated the potential for comparative analysis among the grasses and contributes to our understanding of the anatomy, development, environmental responses and the factors influencing agronomic performance of cereal crops. Since the last publication on Gramene database by D. H. Ware, P. Jaiswal, J. Ni, I. V. Yap, X. Pan, K. Y. Clark, L. Teytelman, S. C. Schmidt, W. Zhao, K. Chang et al. [(2002), Plant Physiol., 130, 1606–1613], the database has undergone extensive changes that are described in this publication
On-farm pig dispatch methods employed in Brazil and stockpeople attitudes on their use
This study surveyed the on-farm dispatching methods used at pig farms, the characteristics of stockpeople operating them, in terms of training and management, and their opinions and attitudes about the efficiency and safety of the applied procedures. Independently of the pig type, the most used dispatching methods at the surveyed Brazilian farms were concussion (90%) and electrocution (5%). Both methods were reported as being efficient and safe for on-farm pig dispatching by most stockpeople (83%). However, 33% of all stockpeople reported they would prefer to use alternative methods, i.e., anesthetics (23%) or electrocution (32%). Only 7% of the stockpeople received training resulting in a more efficient application of the method (P < 0.05). Most stockpeople (96%) declared to feel uncomfortable with the dispatching procedure they use. This discomfort lasted for half a day or longer in 22% of them. The results of this survey suggest that the application of dispatching methods at pig farms may result in animal welfare issues related to the effectiveness of the methods and the attitudes of stockpeople
The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe
The preponderance of matter over antimatter in the early Universe, the
dynamics of the supernova bursts that produced the heavy elements necessary for
life and whether protons eventually decay --- these mysteries at the forefront
of particle physics and astrophysics are key to understanding the early
evolution of our Universe, its current state and its eventual fate. The
Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed
plan for a world-class experiment dedicated to addressing these questions. LBNE
is conceived around three central components: (1) a new, high-intensity
neutrino source generated from a megawatt-class proton accelerator at Fermi
National Accelerator Laboratory, (2) a near neutrino detector just downstream
of the source, and (3) a massive liquid argon time-projection chamber deployed
as a far detector deep underground at the Sanford Underground Research
Facility. This facility, located at the site of the former Homestake Mine in
Lead, South Dakota, is approximately 1,300 km from the neutrino source at
Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino
charge-parity symmetry violation and mass ordering effects. This ambitious yet
cost-effective design incorporates scalability and flexibility and can
accommodate a variety of upgrades and contributions. With its exceptional
combination of experimental configuration, technical capabilities, and
potential for transformative discoveries, LBNE promises to be a vital facility
for the field of particle physics worldwide, providing physicists from around
the globe with opportunities to collaborate in a twenty to thirty year program
of exciting science. In this document we provide a comprehensive overview of
LBNE's scientific objectives, its place in the landscape of neutrino physics
worldwide, the technologies it will incorporate and the capabilities it will
possess.Comment: Major update of previous version. This is the reference document for
LBNE science program and current status. Chapters 1, 3, and 9 provide a
comprehensive overview of LBNE's scientific objectives, its place in the
landscape of neutrino physics worldwide, the technologies it will incorporate
and the capabilities it will possess. 288 pages, 116 figure
Recommended from our members
Gramene: a bird's eye view of cereal genomes
Rice, maize, sorghum, wheat, barley and the other
major crop grasses from the family Poaceae
(Gramineae) are mankind’s most important source
of calories and contribute tens of billions of dollars
annually to the world economy (FAO 1999, http://www.fao.org; USDA 1997, http://www.usda.gov).
Continued improvement of Poaceae crops is necessary
in order to continue to feed an ever-growing
world population. However, of the major crop grasses,
only rice (Oryza sativa), with a compact genome
of ~400 Mbp, has been sequenced and annotated.
The Gramene database (http://www.gramene.org)
takes advantage of the known genetic colinearity
(synteny) between rice and the major crop plant
genomes to provide maize, sorghum, millet, wheat,
oat and barley researchers with the benefits of an
annotated genome years before their own species
are sequenced. Gramene is a one stop portal for
finding curated literature, genetic and genomic datasets
related to maps, markers, genes, genomes and
quantitative trait loci. The addition of several new
tools to Gramene has greatly facilitated the potential
for comparative analysis among the grasses and
contributes to our understanding of the anatomy,
development, environmental responses and the factors
influencing agronomic performance of cereal
crops. Since the last publication on Gramene database
by D. H. Ware, P. Jaiswal, J. Ni, I. V. Yap, X. Pan,
K. Y. Clark, L. Teytelman, S. C. Schmidt, W. Zhao,
K.Changet al. [(2002), Plant Physiol., 130, 1606–1613], the database has undergone extensive changes that
are described in this publication.This is the publisher’s final pdf. The published article is copyrighted by the author(s) and published by Oxford University Press. The published article can be found at: http://nar.oxfordjournals.org/
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