2,845 research outputs found
Agate Fossil Beds National Monument, Paleontological Resources Management Plan (Public Version)
Executive Summary
Since Agate Springs Ranch was founded by James H. Cook in 1887, exquisite examples of transitional Miocene mammalian fauna have been found along this stretch of the Niobrara River valley. Collectively these paleontological discoveries, along with the existing archeological and historical Native American collection, were the basis for establishing Agate Fossil Beds National Monument (AGFO) as a unit of the National Park System (NPS). The fossil remains from the Harrison and Anderson Ranch formations span a short, but important, time period within the Miocene Epoch. AGFO has provided science with an intimate look into North American mammalian evolution of the time that is matched nowhere else, with body fossils and trace fossils (burrows) of many mammals in excellent condition. Investigation of the paleontological resources at AGFO has been very limited since its establishment, but the opportunities for research and discovery are still substantial.
Public and academic interest in the Monument’s paleontological resources are considerable. Although there are existing legal authorities, policies and guidelines regarding the management of paleontological resources, at both the departmental and agency levels, more specific guidance would be helpful for the management of AGFO’s non-renewable fossils. This document has been prepared to provide more specific guidance and recommendations for paleontological resources management at AGFO.
The Introduction outlines the significance of AGFO’s paleontological resources and defines the purpose, need, and objectives for the Agate Fossil Beds National Monument Paleontological Resources Management Plan (PRMP). This plan also identifies the legal authorities, requirements, and mandates underpinning AGFO’s mission as a unit of the NPS, with special attention to authorities that address managing and preserving paleontological resources.
Background Geology and Paleontology provides a basic park geologic description, discusses the scope of AGFO’s paleontological resources, and summarizes past paleontological work performed at the Monument. This information includes historical information from periods both before and after authorization of the Monument as a unit of the NPS. This section also presents the paleontological significance of AGFO and its specimens, such as how AGFO’s taxa are cornerstones of North American geochronology and biostratigraphy.
Paleontological Resources Management begins by listing in greater detail the strategic objectives related to paleontological resources within the NPS and at AGFO. This section then proceeds to discuss the specific considerations related to paleontological resource inventories and monitoring along with management requirements (from policy and guidelines) specific to AGFO. This section discusses what a paleontology inventory is and why, when and how to conduct one; fundamentals of paleontological resource monitoring; the various types of threats to paleontological resources and how to mitigate them; and resource condition assessment and site monitoring protocols. It also addresses how to handle paleontological resources discovered or recovered during other park activities.
Paleontological Research Management presents NPS and AGFO research goals, how to evaluate the scientific significance of research, and how to weigh the significance of research against other park mandates, operations, and goals. The section also includes a description of the permitting process, recommended park-specific permit conditions, and rules for overseeing collection and excavation.
Museum Collections and Curation documents AGFO’s current paleontological collections, collections management and curation policies, AGFO’s photographic archives, collections from AGFO in external repositories, type specimens from AGFO, and Monument compliance with museum security policies.
Interpretation discusses goals and current implementation for how AGFO interprets its paleontological resources for the public. This includes: the primary themes for interpretation; the exhibits, tools and programs used by AGFO to interpret fossil resources; the target audiences for the interpretive programs; teaching good stewardship of paleontological resources; and a discussion of public accessibility to AGFO, its interpretive materials, and the paleontological resources.
Relation of Paleontological Resources to Other Park Programs provides an overview of how each park division may interact with paleontological resources and have their duties cross over with paleontological resource management related actions. It also discusses the potential impacts of paleontological resource management on other types of AGFO resources (archeological, biological, historical, and physical).
Paleontological Resource Data Management discusses various paleontological resource records, datasets, and other archives. AGFO’s paleontological archives and library, as well as their current status, are discussed along with an overview of the type of contents stored within them. The NPS Paleontology Program Archives and Library, and how to exchange data and records between them and the AGFO archives, are also described. This section also reviews geospatial data available to AGFO and issues of sensitivity and confidentially related to paleontological resource data and information.
Finally, the Summary, Conclusions, and Recommendations summarizes the work done on the AGFO PRMP, discusses ongoing and planned projects which assist in implementing the instructions and goals set out in this PRMP, and makes a variety of recommendations for future paleontological resource management at AGFO
Pleistocene/Holocene Cave Fossils From Grand Canyon National Park: Ice Age (Pleistocene) Flora, Fauna, Environments, and Climate of the Grand Canyon, Arizona
The Colorado Plateau is a distinct physiographic province in western North America covering an area of roughly 337,000 km2 (130,115 mi2) across parts of Arizona, Colorado, New Mexico, and Utah. Elevations range from about 360 m (1,180 ft) in the overall Grand Canyon (GC; which includes the Grand Canyon National Park, GRCA) river corridor to an average at the eastern South Rim of 2,072 m (6,800 ft) to 3,850 m (12,630 ft) on the nearby San Francisco Peaks at Flagstaff, Arizona, with an average elevation of 1,525 m (5,000 ft). The Colorado River of Grand Canyon is located along the southwestern portion of the Colorado Plateau in Arizona and is renowned for its dramatic display of geomorphic effects created by fluvial incision and its unique dry-preservation of fossils from the Ice Age (late Pleistocene and Holocene [Quaternary]; most recent 2.58 million years). Although there were at least 22 glacial-interglacial cycles during the Ice Age, this discussion is limited to the most recent episode (called the Wisconsinan Glaciation), which includes the transition to the modern climate (latest Pleistocene and Holocene; the most recent 50,000 years of geologic history)
Psychopathic traits modulate brain responses to drug cues in incarcerated offenders
Recent neuroscientific evidence indicates that psychopathy is associated with abnormal function and structure in limbic and paralimbic areas. Psychopathy and substance use disorders are highly comorbid, but clinical experience suggests that psychopaths abuse drugs for different reasons than non-psychopaths, and that psychopaths do not typically experience withdrawal and craving upon becoming incarcerated. These neurobiological abnormalities may be related to psychopaths\u27 different motivations for-and symptoms of-drug use. This study examined the modulatory effect of psychopathic traits on the neurobiological craving response to pictorial drug stimuli. Drug-related pictures and neutral pictures were presented and rated by participants while hemodynamic activity was monitored using functional magnetic resonance imaging. These data were collected at two correctional facilities in New Mexico using the Mind Research Network mobile magnetic resonance imaging system. The sample comprised 137 incarcerated adult males and females (93 females) with histories of substance dependence. The outcome of interest was the relation between psychopathy scores (using the Hare Psychopathy Checklist-Revised) and hemodynamic activity associated with viewing drug-related pictures vs. neutral pictures. There was a negative association between psychopathy scores and hemodynamic activity for viewing drug-related cues in the anterior cingulate, posterior cingulate, hippocampus, amygdala, caudate, globus pallidus, and parts of the prefrontal cortex. Psychopathic traits modulate the neurobiological craving response and suggest that individual differences are important for understanding and treating substance abuse
Glassy Transition and Aging in a Model without Disorder
We study the off-equilibrium relaxational dynamics of the Amit-Roginsky
field theory, for which the mode coupling approximation is exact. We
show that complex phenomena such as aging and ergodicity breaking are present
at low temperature, similarly to what is found in long range spin glasses. This
is a generalization of mode coupling theory of the structural glass transition
to off-equilibrium situations.Comment: 9 pages, 1 uuencoded figure, LaTex, preprint NORDITA 94/3
Prior exposure to stress allows the maintenance of an ecosystem cycle following severe acidification
Ecosystem processes vary temporally due to environmental fluctuations, such as when variation in solar energy causes diurnal cycles in primary production. This normal variation in ecosystem functioning may be disrupted and even lost if taxa contributing to functioning go extinct due to environmental stress. However, when communities are exposed to the stress at sub-lethal levels over several generations, they may be able to develop community-level stress tolerance via ecological (e.g. species sorting) or evolutionary (e.g. selection for tolerant genotypes) mechanisms and thus avoid the loss of stability, as defined by the resistance of a process. Community tolerance to a novel stressor is expected to increase the resistance of key processes in stressed ecosystems. In freshwater communities we tested whether prolonged prior exposure to an environmental stressor, i.e. acidification, could increase ecosystem stability when the communities were exposed to a subsequent press perturbation of more severe acidification. As a measure of ecosystem stability, we quantified the diurnal variation in dissolved oxygen (DO), and the resistance of the DO cycle and phytoplankton biomass. High-frequency data from oxygen loggers deployed in 12 mesocosms showed that severe acidification with sulfuric acid to pH 3 could cause a temporary (i.e. two-week long) loss of diurnal variation in dissolved oxygen concentration. The loss of diurnal variation was accompanied by a strong reduction in phytoplankton biomass. However, the pre-exposure to acidification for several weeks resulted in the maintenance of the diurnal cycle and higher levels of phytoplankton biomass, though they did not return to as rapidly to pre-exposure functioning as non-exposed mesocosms. These results suggest that ecosystem stability is intrinsically linked to community-wide stress tolerance, and that a history of exposure to the stressor may increase resistance to it, though at the cost of some resilience
Prior selection prevents the loss of an ecosystem cycle during acidification
Ecosystem processes vary temporally due to variation in environmental variables, such as when diurnal variation in sunlight causes diurnal cycles in net primary production. This variability can be characterized by its frequency and amplitude, used to define “normal” functioning of an ecosystem. Relatively little research has addressed how normal modes of variability, such as diurnal cycles, are lost or recovered, following anthropogenic stress. We conducted an aquatic mesocosm experiment to test whether prior application of environmental stress, in the form of moderate acidification, affected the diurnal cycle of dissolved oxygen when exposed to severe acidification. High-frequency data from sensor loggers deployed in 12 mesocosms showed that severe acidification caused a temporary loss of diurnal variation in dissolved oxygen concentration. However, pre-exposure to an acidic environment resulted in the persistence of the diurnal cycle. We hypothesize that pre-exposure shifted the community to acid tolerant genotypes and/or species of algae and other photosynthetic organisms. Our findings suggest that the stability of ecosystem cycles is intrinsically liked to the stress tolerance of the species assemblage
Response of non-equilibrium systems at criticality: Ferromagnetic models in dimension two and above
We study the dynamics of ferromagnetic spin systems quenched from infinite
temperature to their critical point. We show that these systems are aging in
the long-time regime, i.e., their two-time autocorrelation and response
functions and associated fluctuation-dissipation ratio are non-trivial scaling
functions of both time variables. This is exemplified by the exact analysis of
the spherical model in any dimension D>2, and by numerical simulations on the
two-dimensional Ising model. We show in particular that, for (waiting
time) (observation time), the fluctuation-dissipation ratio possesses a
non-trivial limit value , which appears as a dimensionless amplitude
ratio, and is therefore a novel universal characteristic of non-equilibrium
critical dynamics. For the spherical model, we obtain for
24 (mean-field regime). For the two-dimensional
Ising model we measure .Comment: 31 pages, 5 figure
Rare Complications of Cervical Spine Surgery: Pseudomeningocoele.
STUDY DESIGN: This study was a retrospective, multicenter cohort study.
OBJECTIVES: Rare complications of cervical spine surgery are inherently difficult to investigate. Pseudomeningocoele (PMC), an abnormal collection of cerebrospinal fluid that communicates with the subarachnoid space, is one such complication. In order to evaluate and better understand the incidence, presentation, treatment, and outcome of PMC following cervical spine surgery, we conducted a multicenter study to pool our collective experience.
METHODS: This study was a retrospective, multicenter cohort study of patients who underwent cervical spine surgery at any level(s) from C2 to C7, inclusive; were over 18 years of age; and experienced a postoperative PMC.
RESULTS: Thirteen patients (0.08%) developed a postoperative PMC, 6 (46.2%) of whom were female. They had an average age of 48.2 years and stayed in hospital a mean of 11.2 days. Three patients were current smokers, 3 previous smokers, 5 had never smoked, and 2 had unknown smoking status. The majority, 10 (76.9%), were associated with posterior surgery, whereas 3 (23.1%) occurred after an anterior procedure. Myelopathy was the most common indication for operations that were complicated by PMC (46%). Seven patients (53%) required a surgical procedure to address the PMC, whereas the remaining 6 were treated conservatively. All PMCs ultimately resolved or were successfully treated with no residual effects.
CONCLUSIONS: PMC is a rare complication of cervical surgery with an incidence of less than 0.1%. They prolong hospital stay. PMCs occurred more frequently in association with posterior approaches. Approximately half of PMCs required surgery and all ultimately resolved without residual neurologic or other long-term effects
Slow dynamics in critical ferromagnetic vector models relaxing from a magnetized initial state
Within the universality class of ferromagnetic vector models with O(n)
symmetry and purely dissipative dynamics, we study the non-equilibrium critical
relaxation from a magnetized initial state. Transverse correlation and response
functions are exactly computed for Gaussian fluctuations and in the limit of
infinite number n of components of the order parameter. We find that the
fluctuation-dissipation ratios (FDRs) for longitudinal and transverse modes
differ already at the Gaussian level. In these two exactly solvable cases we
completely describe the crossover from the short-time to the long-time
behavior, corresponding to a disordered and a magnetized initial condition,
respectively. The effects of non-Gaussian fluctuations on longitudinal and
transverse quantities are calculated in the first order in the
epsilon-expansion and reliable three-dimensional estimates of the two FDRs are
obtained.Comment: 41 pages, 9 figure
CRI iAtlas: an interactive portal for immuno-oncology research.
The Cancer Research Institute (CRI) iAtlas is an interactive web platform for data exploration and discovery in the context of tumors and their interactions with the immune microenvironment. iAtlas allows researchers to study immune response characterizations and patterns for individual tumor types, tumor subtypes, and immune subtypes. iAtlas supports computation and visualization of correlations and statistics among features related to the tumor microenvironment, cell composition, immune expression signatures, tumor mutation burden, cancer driver mutations, adaptive cell clonality, patient survival, expression of key immunomodulators, and tumor infiltrating lymphocyte (TIL) spatial maps. iAtlas was launched to accompany the release of the TCGA PanCancer Atlas and has since been expanded to include new capabilities such as (1) user-defined loading of sample cohorts, (2) a tool for classifying expression data into immune subtypes, and (3) integration of TIL mapping from digital pathology images. We expect that the CRI iAtlas will accelerate discovery and improve patient outcomes by providing researchers access to standardized immunogenomics data to better understand the tumor immune microenvironment and its impact on patient responses to immunotherapy
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