518 research outputs found
New incision rates on the Colorado River system based on cosmogenic burial dating of terraces : implications for a transient knickpoint at Lees Ferry and differential uplift of the Rocky Mountains
The Green and Colorado Rivers comprise the drainage system of the western slope of the Colorado Rockies and Colorado Plateau. Comparison of river profiles and rates of incision between these rivers provides a natural laboratory for resolving controls on river evolution. Disequilibrium profiles in both rivers are evident by numerous knickpoints and convexities. By compiling existing age constraints and applying cosmogenic burial dating techniques to previously undated bedrock strath terraces, we determine spatial and temporal patterns of incision and profile evolution over the last 10 Ma. In several cases, incision rates are faster below knickpoints than above, suggesting that knickpoints are dynamically evolving and likely migrating upstream. Reconstruction of paleo-profiles from the 640 ka Lava Creek B terrace suggests rates of knickpoint migration of \u3e150 m/ka in soft rock. Hard bedrock often coincides with knickzones and appears to slow knickpoint migration (\u3c50 m/ka). Semi-steady average incision rates of 150 m/Ma over the last ten million years on the upper Colorado has resulted in 1.6 km of incision. The Lees Ferry knickpoint (ca. 950 m elevation) is interpreted to be an upstream-migrating knickpoint initiated by integration of the system through Grand Canyon at about 6 Ma. A burial date of 1.5 +/-0.13 Ma, on a 190-m-high strath terrace 169 km above the knickpoint indicates a rate of 126 m/Ma and is three times older than a cosmogenic surface age of the same terrace. Thus high terraces dated by surface techniques are misleading. This plus a compilation of available incision rates across Lee\u27s Ferry knickpoint show moderate rates of 150- 175 m/Ma below Lees Ferry, ca. 100- 130 m/Ma above the knickpoint in long term rates and 230-300 m/Ma above the knickpoint in very low and young terraces with lower rates farther upstream (e.g. 100 m/Ma on the San Juan and 150 m/Ma near Grand Mesa). Previous authors noted convex features in tributaries above the knickpoint are at elevations between 1200 and 1400 m suggesting they are all responding to a change in incision rate on the Colorado River. Thus longitudinal profiles and incision rates are consistent with diffuse knickpoint propagation extending perhaps 300 km above Lees Ferry on very short time scales. Very high short term rates of 300-500 m/Ma over ~500 ka at Lee\u27s Ferry, and upstream of the knickpoint (e.g. Navajo Mountain, Fremont River and Trachyte Creek) partly result from minimum estimates of age but still may suggest incision rates had increased ca. 500 ka due to knickpoint propagation following slower average incision in the last 1-2 Ma. A new cosmogenic burial isochron date of 1.48 +/-0.12 Ma on an abandoned meander 60 m above the river in upper Desolation Canyon gives an incision rate of 40 m/Ma. Thus, the Green River below Canyon of Lodore displays much slower incision rates relative to a similar distance upstream on the Colorado River. The combination of higher gradient, higher discharge, and higher incision rates over the last several million years, for the upper Colorado River relative to the Green, is interpreted to be due to differential rock uplift of the Colorado Rockies relative to the Canyonlands and Uinta Basin regions. This may be driven by mantle bouyancy associated with the Aspen Anomaly of central Colorado. The overall conclusions of this paper are that: 1) differential incision across the Lees Ferry and Desolation knickpoints records upstream-propagating incision transients in a disequilibrium river system; 2) the upper Colorado River system is incising faster than the Green River over the last several million years due to rock uplift of the Colorado Rockies relative to the central Colorado Plateau
Parallel implementation of maximum parsimony search algorithm on multicore CPUs
Phylogenetics is the study of the evolutionary relationships among species. It is derived from the ancient greek words, phylon meaning race , and genetikos, meaning relative to birth . An important methodology in phylogenetics is a cladistics methodology (parsimony) applied to the study of taxonomic classification. Modern study includes as source data aspects of molecular biology, such as the DNA sequence of homologous (orthologous) genes. The algorithms used attempt to reconstruct evolutionary relationships in the form of phylogenetic trees, based on the available morphological data, behavioral data, and usually DNA sequence data (Fitch W. M., 1971). The topic of this thesis is the parallel implementation of an existing algorithm called Maximum Parsimony, a search for a guaranteed optimal tree(s) based the fewest number of mutations required for tree construction. The algorithm grows linearly with the increase in DNA sequence length and combinatorially with the number of organisms studied (Felsenstein J. , The number of evolutionary trees., 1978). The algorithm may take hours to complete. The limitations of the current implementations such as PAUP are that they are limited to just one core on the CPU, even if 8 are available. This parallel implementation may use as many cores as are available. The method of research is to replicate the accuracy of existing serial software, parallelize the algorithm to many cores without losing accuracy, optimize by various methods, then attempt to port to other hardware architectures. Some time is spent on the implementation of the algorithms onto GPUs and Clusters. The results are that, while this implementation matches the accuracy of the current standard, and speeds up in parallel, it does not presently match the speed of PAUP for reasons yet to be determined
Searching for high-redshift centimeter-wave continuum, line and maser emission using the Square Kilometer Array
We discuss the detection of redshifted line and continuum emission at radio
wavelengths using a Square Kilometer Array (SKA), specifically from
low-excitation rotational molecular line transitions of CO and HCN (molecular
lines), the recombination radiation from atomic transitions in almost-ionized
hydrogen (radio recombination lines; RRLs), OH and water maser lines, as well
as from synchrotron and free-free continuum radiation and HI 21-cm line
radiation. The detection of radio lines with the SKA offers the prospect to
determine the redshifts and thus exact luminosities for some of the most
distant and optically faint star-forming galaxies and active galactic nuclei
(AGN), even those galaxies that are either deeply enshrouded in interstellar
dust or shining prior to the end of reionization. Moreover, it provides an
opportunity to study the astrophysical conditions and resolved morphologies of
the most active regions in galaxies during the most active phase of star
formation at redshift z~2. A sufficiently powerful and adaptable SKA correlator
will enable wide-field three-dimensional redshift surveys at chosen specific
high redshifts, and will allow new probes of the evolution of large-scale
structure (LSS) in the distribution of galaxies. The detection of molecular
line radiation favours pushing the operating frequencies of SKA up to at least
26 GHz, and ideally to 40 GHz, while very high redshift maser emissions
requires access to about 100 MHz. To search for LSS the widest possible
instantaneous field of view would be advantageous.Comment: 12 pages, 2 figures. To appear in "Science with the Square Kilometer
Array," eds. C. Carilli and S. Rawlings, New Astronomy Reviews (Elsevier:
Amsterdam
Development of a Desktop Reference for Medication Assisted Treatment (MAT)
This project was to develop a physician desktop reference to assist with medication assisted treatment (MAT) for opioid use disorder. It was developed in conjunction with MAT team members and family medicine physicians to serve as a reference of both commonly needed medical information and local contact information for community resources.https://scholarworks.uvm.edu/fmclerk/1594/thumbnail.jp
Associations between the Adult ADHD Self-Report Rating Scale and the Test of Differential Inhibition and Attention
Attention-Deficit/Hyperactivity Disorder (ADHD) ranks among the most common mental health disorders in adults (APA, 2013). ADHD assessment is complicated by heterogenous symptoms, gender and age differences in diagnosis, variability in symptom manifestation across the lifespan, and comorbidity with other psychiatric disorders and medical conditions (Asherson, 2016; Willcut, 2012; Williamson & Johnston, 2015). The stop-signal task (SST) identifies ADHD clinical groups in children and adults (Lifffijt et al., 2005), yet it remains unclear whether SST performance reflects general deficits in attention (Alderson et al., 2007) or a selective deficit in motor response inhibition (Aron & Poldrack, 2005). Studies of SST often involve lower cognitive complexity without the additional inhibitory load produced by interference control (Uno et al., 2006). Currently, there is no research on SST with interference control in the adult population. The aim of this study was to assess the diagnostic utility of response inhibition metrics in the adult population on tasks with greater central processing demands. Forty-nine adults completed the Adult ADHD Self-Report Scale â V1.1 Symptoms Checklist and the Test of Differential Inhibition and Attention (TDIA). Results from hierarchical multiple linear regression analyses showed that TDIA metrics associated with motor response inhibition significantly predicted self-reported symptoms of inattention, hyperactivity-impulsivity, and combined ADHD, over and above metrics representing general attention. This study supports the clinical utility of SST with interference control in identifying ADHD in adults. Furthermore, the results support a conceptual model of ADHD wherein response control deficits are primary to the executive dysfunction associated with the disorder. Possible explanations for these results, limitations of the study, and future directions are explored
ELDER LAWâMY LIFE, MY CHOICE
As the most recent past president of the National Academy of Elder Law Attorneys (NAELA) I have been involved in elder law for over thirty years, even before there was a sub-practice of estate planning called elder law. In fact, for estate planning, I recall when the primary document a client needed was a will. The required document has expanded and now includes a will, health proxy, power of attorney, a POLST form (Physicianâs Order for Life Sustaining Treatment), sometimes a living will, and other various documents a client may desire, such as a cremation order, a pre-arranged burial, and the like.
Many years ago, it was also the norm that many wished to be kept alive by machines, or did not take a stand as to their preference, with many families refusing to talk about it. It was also the norm that most people were buried and not cremated. Times have changed, and the pendulum has swung the other way in many cases. I remember how my mother was ill for many years, and it was determined that all measures would be taken to keep her alive, even at the end of her life when there was absolutely no chance of recovery
Mauve Assembly Metrics
Summary: High-throughput DNA sequencing technologies have spurred the development of numerous novel methods for genome assembly. With few exceptions, these algorithms are heuristic and require one or more parameters to be manually set by the user. One approach to parameter tuning involves assembling data from an organism with an available high-quality reference genome, and measuring assembly accuracy using some metrics
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