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 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 Beaver and state transition in Yellowstone

2017 ◽  
Vol 40 ◽  
pp. 23-30
Author(s):  
Marjorie L. Brooks
Keyword(s):  
Cervus Elaphus ◽  
State Transition ◽  
Castor Canadensis ◽  
Keystone Species ◽  
Experimental System ◽  
Environmental Research ◽  
Colorado State University ◽  
Resource Limitations ◽  
Underlying Mechanisms ◽  
Sustained Recovery

Extirpation of wolves from the Greater Yellowstone Ecosystem (GYE) in the 1920shypothetically triggered a behaviorally-mediated trophic cascade in which elk (Cervus elaphus), released from the fear of wolf (Canis lupus) predation, over-browsed riparian zones. Eventually, vast areas of meadow-wetland complexes transitioned to grass-lodgepole systems. The importance of beaver (Castor canadensis) in wetland losses has received less attention. Beaver abandoned most of the GYE by the 1950s, possibly due to resource limitations. Researchers from Colorado State University established an experimental system for Long Term Environmental Research in Biology (LTREB) along several streams in the Lamar Valley of Yellowstone sixteen years ago. To evaluate effects of hydrologic changes and elk browsing on productivity of willows (Salix spp.) and state transition, they built small experimental dams with browsing exclosures. In 2015, beaver began recolonizing the region. I am investigating how their biologic as well as hydrologic impacts affect the underlying mechanisms of state transition: nutrient cycling, productivity, and stream respiration. I posit that beaver are keystone species, meaning that the sustained recovery of wetland-meadow complexes is unlikely without the higher levels of riparian productivity triggered by the biological influence of beaver.   Featured photo by Ben Amaral on Unsplash. https://unsplash.com/photos/rohY54N6auU

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.

Response Interference as a Mechanism Underlying Implicit Measures

2008 ◽  
Vol 24 (4) ◽  
pp. 218-225 ◽  
Author(s):  
Bertram Gawronski ◽  
Roland Deutsch ◽  
Etienne P. LeBel ◽  
Kurt R. Peters
Keyword(s):  
Task Performance ◽  
Psychological Research ◽  
Implicit Measures ◽  
Mediation Model ◽  
Response Interference ◽  
Relevant Evidence ◽  
Moderated Mediation Model ◽  
Stimulus Features ◽  
Underlying Mechanisms

Over the last decade, implicit measures of mental associations (e.g., Implicit Association Test, sequential priming) have become increasingly popular in many areas of psychological research. Even though successful applications provide preliminary support for the validity of these measures, their underlying mechanisms are still controversial. The present article addresses the role of a particular mechanism that is hypothesized to mediate the influence of activated associations on task performance in many implicit measures: response interference (RI). Based on a review of relevant evidence, we argue that RI effects in implicit measures depend on participants’ attention to association-relevant stimulus features, which in turn can influence the reliability and the construct validity of these measures. Drawing on a moderated-mediation model (MMM) of task performance in RI paradigms, we provide several suggestions on how to address these problems in research using implicit measures.

The More You Say, the Less They Hear

2015 ◽  
Vol 27 (4) ◽  
pp. 159-169 ◽  
Author(s):  
Elsbeth D. Asbeek Brusse ◽  
Marieke L. Fransen ◽  
Edith G. Smit
Keyword(s):  
Hearing Protection ◽  
Entertainment Education ◽  
Mediating Role ◽  
Attitude Measures ◽  
Underlying Mechanisms

Abstract. This study examined the effects of disclosure messages in entertainment-education (E-E) on attitudes toward hearing protection and attitude toward the source. In addition, the (mediating) role of the underlying mechanisms (i.e., transportation, identification, and counterarguing) was studied. In an experiment (N = 336), three different disclosure messages were compared with a no-disclosure condition. The results show that more explicit disclosure messages negatively affect transportation and identification and stimulate the generation of counterarguments. In addition, the more explicit disclosure messages affect both attitude measures via two of these processes (i.e., transportation and counterarguing). Less explicit disclosure messages do not have this effect. Implications of the findings are discussed.

Autophagy Modulators and Neuroinflammation

2020 ◽  
Vol 27 (6) ◽  
pp. 955-982 ◽  
Author(s):  
Kyoung Sang Cho ◽  
Jang Ho Lee ◽  
Jeiwon Cho ◽  
Guang-Ho Cha ◽  
Gyun Jee Song
Keyword(s):  
Neurodegenerative Disorders ◽  
Neurological Disorders ◽  
Mammalian Cells ◽  
Critical Role ◽  
Therapeutic Agents ◽  
Mechanisms Of Action ◽  
Scientific Interest ◽  
Therapeutic Tools ◽  
Underlying Mechanisms

Background: Neuroinflammation plays a critical role in the development and progression of various neurological disorders. Therefore, various studies have focused on the development of neuroinflammation inhibitors as potential therapeutic tools. Recently, the involvement of autophagy in the regulation of neuroinflammation has drawn substantial scientific interest, and a growing number of studies support the role of impaired autophagy in the pathogenesis of common neurodegenerative disorders. Objective: The purpose of this article is to review recent research on the role of autophagy in controlling neuroinflammation. We focus on studies employing both mammalian cells and animal models to evaluate the ability of different autophagic modulators to regulate neuroinflammation. Methods: We have mostly reviewed recent studies reporting anti-neuroinflammatory properties of autophagy. We also briefly discussed a few studies showing that autophagy modulators activate neuroinflammation in certain conditions. Results: Recent studies report neuroprotective as well as anti-neuroinflammatory effects of autophagic modulators. We discuss the possible underlying mechanisms of action of these drugs and their potential limitations as therapeutic agents against neurological disorders. Conclusion: Autophagy activators are promising compounds for the treatment of neurological disorders involving neuroinflammation.

Inflammatory Biomarkers in Atrial Fibrillation

2019 ◽  
Vol 26 (5) ◽  
pp. 837-854 ◽  
Author(s):  
Effimia Zacharia ◽  
Nikolaos Papageorgiou ◽  
Adam Ioannou ◽  
Gerasimos Siasos ◽  
Spyridon Papaioannou ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Plasma Levels ◽  
Large Scale ◽  
Inflammatory Biomarkers ◽  
Inflammatory Pathways ◽  
Inflammatory State ◽  
Anti Inflammatory ◽  
Underlying Mechanisms

During the last few years, a significant number of studies have attempted to clarify the underlying mechanisms that lead to the presentation of atrial fibrillation (AF). Inflammation is a key component of the pathophysiological processes that lead to the development of AF; the amplification of inflammatory pathways triggers AF, and, in tandem, AF increases the inflammatory state. Indeed, the plasma levels of several inflammatory biomarkers are elevated in patients with AF. In addition, the levels of specific inflammatory biomarkers may provide information regarding to the AF duration. Several small studies have assessed the role of anti-inflammatory treatment in atrial fibrillation but the results have been contradictory. Large-scale studies are needed to evaluate the role of inflammation in AF and whether anti-inflammatory medications should be routinely administered to patients with AF.

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