scholarly journals Unlocking the biogeochemical role of beaver in state-transition of landscapes in Yellowstone's northern range: Tantalizing insights, initial results, and evolving research design

2019 ◽  
Vol 42 ◽  
pp. 70-79
Author(s):  
Marjorie L. Brooks
Keyword(s):  
Repeated Measures ◽  
Nutrient Dynamics ◽  
State Transition ◽  
Genetic Identification ◽  
Environmental Research ◽  
State Transitions ◽  
Greater Yellowstone Ecosystem ◽  
Field Samples ◽  
Greater Yellowstone

Extirpation of wolves from the Greater Yellowstone Ecosystem in the 1920s hypothetically triggered a trophic cascade in which herbivores over-browsed riparian zones once released from the fear of wolf (Canis lupus) predation. Eventually, vast meadow-wetland complexes transitioned to grass-lodgepole systems. By 1954, beaver (Castor canadensis) virtually abandoned the Greater Yellowstone Ecosystem. In 2000, Colorado State University established experimental dams with browsing exclosures for Long Term Environmental Research in Biology (LTREB) on three streams in Lamar Valley to compare hydrologic effects of pseudo-beaver dams and browsing on willow (Salix spp.) productivity and state transitions. In 2015, beaver began recolonizing the region. I investigate how the biogeochemical role of beaver versus their hydrologic influence affects the underlying mechanisms of state transition: nutrient cycling, productivity, and stream respiration. Analyses of the 2017 field samples showed that beaver streams trend toward higher nutrient levels and higher variances than the LTREB sites. These trends continued in 2018 and 2019. The data tentatively support the role of beaver as keystone species in state transitions. Interannual modeling of nutrient dynamics, comparisons of stream metabolism, and genetic identification of microbial communities are underway. Similarly, analyses of the repeated measures collected across the month of July 2019 are underway.   Featured photo from figure 1 in report.

scholarly journals Unlocking the biogeochemical role of beaver in state-transition of landscapes in Yellowstone's northern range

2018 ◽  
Vol 41 ◽  
pp. 55-64
Author(s):  
Marjorie L. Brooks
Keyword(s):  
State Transition ◽  
Castor Canadensis ◽  
Keystone Species ◽  
Environmental Research ◽  
State Transitions ◽  
Greater Yellowstone Ecosystem ◽  
Field Samples ◽  
Greater Yellowstone ◽  
Underlying Mechanisms

Extirpation of wolves from the Greater Yellowstone Ecosystem in the 1920s hypothetically triggered a trophic cascade in which browsers, released from wolf (Canis lupus) predation, over-browsed riparian zones. Eventually, vast meadow-wetland complexes transitioned to grass-lodgepole systems. By 1954, beaver (Castor canadensis) virtually abandoned the Greater Yellowstone Ecosystem. In 2000, Colorado State University established experimental dams with browsing exclosures for Long Term Environmental Research in Biology (LTREB) on three streams in Lamar Valley to compare hydrologic effects of pseudo-beaver dams and browsing on willow (Salix spp.) productivity and state transitions. In 2015, beaver began recolonizing the region. I investigated how the biogeochemical role of beaver versus their hydrologic influence affects the underlying mechanisms of state transition: nutrient cycling, productivity, and stream respiration. Analyses of the 2017 field samples show that beaver streams trend toward higher nutrient levels and higher variances than the LTREB sites. The data tentatively support the role of beaver as keystone species in state transitions, although more data are needed. The unexpected and late May notice from the NPS to obtain an independent research permit—approved late August—curtailed my 2018 research to a brief field bout in September. Analysis of 2018 samples is underway.   Featured photo from Figure 1 in report.

scholarly journals Studies of Parasitic Wasps (Hymenoptera: Braconidae) in Association with Mountain Pine Beetle Outbreak

2012 ◽  
Vol 35 ◽  
pp. 81-90
Author(s):  
Larry Haimowitz ◽  
Scott Shaw
Keyword(s):  
Bark Beetle ◽  
Mountain Pine Beetle ◽  
Parasitoid Wasps ◽  
Greater Yellowstone Ecosystem ◽  
Local Diversity ◽  
Mountain Pine ◽  
Pine Beetle ◽  
Greater Yellowstone ◽  
New Distribution

A survey of parasitoid wasps (Hymenoptera: Braconidae) in Grand Teton National Park reveals undiscovered (but not unexpected) diversity, as well as changes in diversity associated with the bark beetle epidemic and the unusually warm, dry year. Our 2012 survey found nearly the same number of Braconidae subfamilies (18 vs 19) as a 2002 survey (Shaw 2002); a remarkable amount of diversity given that the 2002 survey was based upon five times as many specimens. Eleven species found in this study are new distribution records for the Greater Yellowstone Ecosystem (GYE), which points to much undiscovered local diversity. Differences from previous studies are possibly due to the unusual warmth and dryness of spring 2012, along with some influence from beetle kill. We provide a list of parasitoids and predators associated with mountain pine beetle (Dendroctonus ponderosae Hopkins) in the Greater Yellowstone Ecosystem (GYE), a stepping stone for further research to determine the role of natural enemies in bark beetle outbreak dynamics in the GYE.

Schizophrenia as a Disorder of Cerebral State Transition

1986 ◽  
Vol 20 (2) ◽  
pp. 167-178 ◽  
Author(s):  
J. J. Wright ◽  
R. R. Kydd
Keyword(s):  
State Transition ◽  
Finite State Machines ◽  
The State ◽  
State Transitions ◽  
Brain State ◽  
State Machines ◽  
Electrocortical Activity ◽  
Wave Nature ◽  
Finite State

This paper offers a speculative consideration of the schizophrenic process in the light of recent findings concerning the wave nature of electrocortical activity. These findings indicate that changes of brain state can be described in the terminology of finite-state machines, and both the instantaneous states and the state transitions can be specified. It is suggested that the mental phenomena of schizophrenia may be reducible to events (some specific type of instability) which could be observed by appropriate analytic techniques applied to EEG. Present empirical EEG findings in schizophrenics are reviewed in this light, and the role of dopamine blockade in treatment is also considered.

scholarly journals Metabolic–Epigenetic Axis in Pluripotent State Transitions

Epigenomes ◽  
2019 ◽  
Vol 3 (3) ◽  
pp. 13 ◽  
Author(s):  
Cristina D’Aniello ◽  
Federica Cermola ◽  
Eduardo J. Patriarca ◽  
Gabriella Minchiotti
Keyword(s):  
Pluripotent Stem Cells ◽  
Pluripotent Stem Cell ◽  
State Transition ◽  
Adult Life ◽  
State Transitions ◽  
Chromatin Modifications ◽  
Epigenetic Changes ◽  
Epigenetic Remodeling ◽  
Induced Pluripotent

Cell state transition (CST) occurs during embryo development and in adult life in response to different stimuli and is associated with extensive epigenetic remodeling. Beyond growth factors and signaling pathways, increasing evidence point to a crucial role of metabolic signals in this process. Indeed, since several epigenetic enzymes are sensitive to availability of specific metabolites, fluctuations in their levels may induce the epigenetic changes associated with CST. Here we analyze how fluctuations in metabolites availability influence DNA/chromatin modifications associated with pluripotent stem cell (PSC) transitions. We discuss current studies and focus on the effects of metabolites in the context of naïve to primed transition, PSC differentiation and reprogramming of somatic cells to induced pluripotent stem cells (iPSCs), analyzing their mechanism of action and the causal correlation between metabolites availability and epigenetic alteration.

scholarly journals Ecology of the Greater Yellowstone Ecosystem

2011 ◽  
Vol 34 ◽  
pp. 195-195
Author(s):  
Scott Carleton
Keyword(s):  
Species Composition ◽  
National Parks ◽  
Life Histories ◽  
Greater Yellowstone Ecosystem ◽  
Data Sets ◽  
Individual Tree ◽  
Successional Stages ◽  
Greater Yellowstone

During June, 2010 six wildlife students from Laramie, WY traveled to Grand Teton and Yellowstone National Parks for a 10 day course on the Ecology of the Greater Yellowstone Ecosystem. The course focused on the vegetation, animals, geology, and management challenges concerning the parks. For each of the components, a student gave a brief introduction to the class on the topic we would be exploring that day. Students learned to identify trees using dichotomous keys and then spent the day in the field performing vegetation transects in recently burned to mature forests within the parks. Students then used their data sets to make inferences into species composition and the process of succession across the landscape. Students learned about individual tree life histories. including the role of serotiny in early forest successional stages following a fire.

Performance Evaluation Tests for Environmental Research (Peter): Evaluation of 114 Measures

1986 ◽  
Vol 63 (2) ◽  
pp. 683-708 ◽  
Author(s):  
Alvah C. Bittner ◽  
Robert C. Carter ◽  
Robert S. Kennedy ◽  
Mary M. Harbeson ◽  
Michele Krause
Keyword(s):  
Performance Evaluation ◽  
Repeated Measures ◽  
Time Course ◽  
Environmental Studies ◽  
Acceptable Level ◽  
Environmental Research ◽  
Human Capabilities ◽  
Task Definition ◽  
And Task

The goal of the Performance Evaluation Tests for Environmental Research (PETER) Program was to identify a set of measures of human capabilities for use in the study of environmental and other time-course effects. 114 measures studied in the PETER Program were evaluated and categorized into four groups based upon task stability and task definition. The Recommended category contained 30 measures that clearly obtained total stabilization and had an acceptable level of reliability efficiency. The Acceptable-But-Redundant category contained 15 measures. The 37 measures in the Marginal category, which included an inordinate number of slope and other derived measures, usually had desirable features which were outweighed by faults. The 32 measures in the Unacceptable category had either differential instability or weak reliability efficiency. It is our opinion that the 30 measures in the Recommended category should be given first consideration for environmental research applications. Further, it is recommended that information pertaining to preexperimental practice requirements and stabilized reliabilities should be utilized in repeated-measures environmental studies.

scholarly journals Defining Sustainability in the Greater Yellowstone Ecosystem

2018 ◽  
Vol 11 (1) ◽  
pp. 32 ◽  
Author(s):  
Ryan D. Bergstrom
Keyword(s):  
National Parks ◽  
Decision Makers ◽  
Greater Yellowstone Ecosystem ◽  
Community Stakeholders ◽  
Gateway Communities ◽  
Starting Point ◽  
Greater Yellowstone ◽  
Effective Decision Making ◽  
Collective Resource ◽  
Time In Residence

Because of the normative and subjective nature of the terms sustainability and sustainable development, solutions tend to be applicable for specific regions but not the whole of society. Thus, it is imperative understand better how community stakeholders and decision makers define the concept of sustainability. Not only will greater understanding of such definitions add to our understanding of nature-society relations, but also in certain contexts, this understanding may help to promote realistic and effective decision-making at local levels. The objective of this study was to determine how amenity-driven gateway communities surrounding Yellowstone and Grand Teton National parks define, conceptualize, and perceive sustainability, and if those perceptions varied between time in residence, community of origin, or role within the community. Thirty-five key informant interviews were conducted with decision makers within the Greater Yellowstone Ecosystem to meet the study objectives. Throughout study communities, definitions of sustainability focused on the environment, the economy, and multi-generational thinking, and it is believed that these similarities can be the starting point for communication and collaboration among gateway communities, the long-term sustainability of their individual communities, and the collective resource upon which they all depend, the Greater Yellowstone Ecosystem.

scholarly journals Lead exposure in large carnivores in the greater Yellowstone ecosystem

2011 ◽  
Vol 76 (3) ◽  
pp. 575-582 ◽  
Author(s):  
Thomas A. Rogers ◽  
Bryan Bedrosian ◽  
Jon Graham ◽  
Kerry R. Foresman
Keyword(s):  
Lead Exposure ◽  
Greater Yellowstone Ecosystem ◽  
Large Carnivores ◽  
Greater Yellowstone

scholarly journals On Synchronizing Coupled Retinogeniculocortical Pathways: A Toy Model

2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
B. L. Mayer ◽  
L. H. A. Monteiro
Keyword(s):  
Neural Network ◽  
Visual Cortex ◽  
Corpus Callosum ◽  
Neuronal Activity ◽  
Network Topology ◽  
Cerebral Hemisphere ◽  
State Transition ◽  
Regular Lattice ◽  
Visual Cortices

A Newman-Watts graph is formed by including random links in a regular lattice. Here, the emergence of synchronization in coupled Newman-Watts graphs is studied. The whole neural network is considered as a toy model of mammalian visual pathways. It is composed by four coupled graphs, in which a coupled pair represents the lateral geniculate nucleus and the visual cortex of a cerebral hemisphere. The hemispheres communicate with each other through a coupling between the graphs representing the visual cortices. This coupling makes the role of the corpus callosum. The state transition of neurons, supposed to be the nodes of the graphs, occurs in discrete time and it follows a set of deterministic rules. From periodic stimuli coming from the retina, the neuronal activity of the whole network is numerically computed. The goal is to find out how the values of the parameters related to the network topology affect the synchronization among the four graphs.

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