Birth and Evolution of the Virgin River: ~1 km of post-5 Ma uplift of the western Colorado Plateau

The uplift history of the Colorado Plateau has been debated for over a century with still no unified hypotheses for the cause, timing, and rate of uplift. 40Ar/39Ar dating of semi-continuous basaltic volcanism over the past ~6 Ma within the Virgin River drainage system, southwest Utah and southern Nevada, provides a way to calibrate differential river incision and compare patterns of basaltic migration, mantle velocity structure, channel steepness, lithology, incision history and the birth and evolution of the Virgin River. New detrital sanidine ages constrain the arrival of the Virgin River across the Virgin Mountains to a maximum depositional age of 5.9 Ma. Incision magnitudes and rates of the Virgin River show a stair-step increase in bedrock incision as the river crosses multiple N-S trending normal faults. Average calculated rates are 23 m/Ma in the Lake Mead block, 85 m/Ma in the combined St. George and Hurricane blocks, and 338 m/Ma in the Zion block. Block-to-block differential incision adds cumulatively such that the Zion block has been deeply incised ~1 km (~315 m/Ma) over 3.6 Ma relative to the Colorado River confluence. We test two hypotheses: 1) observed differential incision magnitudes and rates along the Virgin River system are a measure of mantle-driven differential uplift of the Colorado Plateau relative to sea level over the past ~5 Ma. 2) Observed differential river incision relates to river integration across previously uplifted topography and differential rock types with no post 5 Ma uplift. Strong correlations exist between high channel steepness (ksn) and low mantle velocities throughout the Virgin River drainage while weaker correlations exist between high ksn and resistant lithologies. Basaltic volcanism, which has migrated at a rate of ~18 km/Ma parallel to the Virgin River between ~13 and 0.5 Ma suggests a possible mantle-driven mechanism for the combined observations of differential uplift across faults and additional young Colorado Plateau epeirogenic uplift tracked by headward river propagation. Thus, we interpret the Virgin River to be a \u3c 4.5 Ma disequilibrium river system responding to ongoing upper mantle modification and related basalt extraction, which is driving ~ 1 km of young uplift of the western Colorado Plateau

ARXPS-studies ofcˆ-axis textured YBa2Cu3Ox-films

YBa2Cu3Ox sputter deposited cold on MgO grows in O2 annealing epitaxially to a transparent, superconducting film with Tc 80K. The unscraped surfaces of these films are smooth showing XPS lines changing with photoelectron take-off angle. This enhanced data base allows to separate the different chemical compounds (hydroxide, peroxide, carbonate, carboxyle, cuprate, graphite ...) and to obtain their spatial distribution. This yields the compounds, their amount and distribution making up the cinder growing with O2-anneal at internal and external surfaces. The cinder stoichiometry gives insights in the chemistry going on in O2 annealing. Below the cinder the signature ofcˆ-axis oriented YBa2Cu3Ox is identified, showing that a Ba-oxide layer forms the stable surface. This coats insulating CuO2 and Y-oxide layers yielding so an intrinsic dead layer

First-Year Student Perceptions of a Community College Success Course: A Phenomenological Approach

The use of college success courses by community colleges in recent years has had a significant impact on the academic success of their first-year students. Although studies have shown increases in grade point averages and retention rates for students enrolled in success courses, few have examined student perspectives of these courses. The intention of this study was to gain an understanding of the student perceptions of college success courses and how they shaped their college experiences. By using a phenomenological method of inquiry, the researcher interviewed six community college students enrolled in a college success course. The participants were students of first-year status of which three were on academic probation and three were in good academic standing. Results showed that participants perceived the course to be instrumental in improving their self-image, abilities to forge relationships, academic competence and student engagement. Participants discussed the impact college success courses had on the development of their sense of belonging and academic aptitude and how these factors helped shape their college transition

COVID-19 as a nonprofit workplace crisis: Seeking insights from the nonprofit workers’ perspective

Due to the COVID-19 pandemic, nonprofit organizations face increased demands for services alongside decreased revenues and must make tough choices on how to weather these stressors. Alongside these organizational changes, COVID-19 impacts nonprofit workers and could be a career shock for these individuals, potentially altering how they think of their work and career intentions, even jeopardizing their commitment to the sector. Therefore, this paper outlines a research agenda to understand how the pandemic impacts nonprofit workers and their commitment to working in the sector. Several areas for future research are identified including human resource policy, leadership development, generational differences, gender effects, nonprofit graduate education, and mission-specific work effects

Sharing Classical Secrets with Continuous Variable Entanglement Composable Security and Network Coding Advantage

Secret sharing is a multiparty cryptographic primitive that can be applied to a network of partially distrustful parties for encrypting data that is both sensitive it must remain secure and important it must not be lost or destroyed . When sharing classical secrets as opposed to quantum states , one can distinguish between protocols that leverage bipartite quantum key distribution QKD and those that exploit multipartite entanglement. The latter class are known to be vulnerable to so called participant attacks and, while progress has been made recently, there is currently no analysis that quantifies their performance in the composable, finite size regime, which has become the gold standard for QKD security. Given this and the fact that distributing multipartite entanglement is typically challenging one might well ask is there any virtue in pursuing multipartite entanglement based schemes? Here, we answer this question in the affirmative for a class of secret sharing protocols based on continuous variable graph states. We establish security in a composable framework and identify a network topology, specifically a bottleneck network of lossy channels, and parameter regimes within the reach of present day experiments for which a multipartite scheme outperforms the corresponding QKD based method in the asymptotic and finite size setting. Finally, we establish experimental parameters where the multipartite schemes outperform any possible QKD based protocol. This is one of the first concrete compelling examples of multipartite entangled resources achieving a genuine advantage over point to point protocols for quantum communication and represents a rigorous, operational benchmark to assess the usefulness of such resource

Improved profile fitting and quantification of uncertainty in experimental measurements of impurity transport coefficients using Gaussian process regression

The need to fit smooth temperature and density profiles to discrete observations is ubiquitous in plasma physics, but the prevailing techniques for this have many shortcomings that cast doubt on the statistical validity of the results. This issue is amplified in the context of validation of gyrokinetic transport models (Holland et al 2009 Phys. Plasmas 16 052301), where the strong sensitivity of the code outputs to input gradients means that inadequacies in the profile fitting technique can easily lead to an incorrect assessment of the degree of agreement with experimental measurements. In order to rectify the shortcomings of standard approaches to profile fitting, we have applied Gaussian process regression (GPR), a powerful non-parametric regression technique, to analyse an Alcator C-Mod L-mode discharge used for past gyrokinetic validation work (Howard et al 2012 Nucl. Fusion 52 063002). We show that the GPR techniques can reproduce the previous results while delivering more statistically rigorous fits and uncertainty estimates for both the value and the gradient of plasma profiles with an improved level of automation. We also discuss how the use of GPR can allow for dramatic increases in the rate of convergence of uncertainty propagation for any code that takes experimental profiles as inputs. The new GPR techniques for profile fitting and uncertainty propagation are quite useful and general, and we describe the steps to implementation in detail in this paper. These techniques have the potential to substantially improve the quality of uncertainty estimates on profile fits and the rate of convergence of uncertainty propagation, making them of great interest for wider use in fusion experiments and modelling efforts.United States. Dept. of Energy. Office of Fusion Energy Sciences (Award DE-FC02-99ER54512)United States. Dept. of Energy. Office of Science (Contract DE-AC05-06OR23177)United States. Dept. of Energy. Office of Advanced Scientific Computing Research (Award DE-SC0007099

Impact of Experimental Hookworm Infection on the Human Gut Microbiota

The interactions between gastrointestinal parasitic helminths and commensal bacteria are likely to play a pivotal role in the establishment of host-parasite cross-talk, ultimately shaping the development of the intestinal immune system. However, little information is available on the impact of infections by gastrointestinal helminths on the bacterial communities inhabiting the human gut. We used 16S rRNA gene amplification and pyrosequencing to characterize, for the first time to our knowledge, the differences in composition and relative abundance of fecal microbial communities in human subjects prior to and following experimental infection with the blood-feeding intestinal hookworm, Necator americanus. Our data show that, although hookworm infection leads to a minor increase in microbial species richness, no detectable effect is observed on community structure, diversity or relative abundance of individual bacterial species

Harnessing symmetry protected topological order for quantum memories

Spin chains with symmetry protected edge modes are promising candidates to realize intrinsically robust physical qubits that can be used for the storage and processing of quantum information. In any experimental realization of such physical systems, weak perturbations in the form of induced interactions and disorder are unavoidable and can be detrimental to the stored information. At the same time, the latter may in fact be beneficial; for instance, by deliberately inducing disorder which causes the system to localize. We explore the potential of using an XZX cluster Hamiltonian to encode quantum information into the local edge modes and comprehensively investigate the influence of both many body interactions and disorder on their stability over time, adding substance to the narrative that many body localization may stabilize quantum information. We recover the edge state at each time step, allowing us to reconstruct the quantum channel that captures the locally constrained out of equilibrium time evolution. With this representation in hand, we analyze how well classical and quantum information are preserved over time as a function of disorder and interactions. We find that the performance of the edge qubits varies dramatically between disorder realizations. Whereas some show a smooth decoherence over time, a sizable fraction is rapidly rendered unusable as memories. We also find that the stability of the classical information a precursor for the usefulness of the chain as a quantum memory depends strongly on the direction in which the bit is encoded. When employing the chain as a genuine quantum memory, encoded qubits are most faithfully recovered for low interaction and high disorde

Vaginal biogenic amines: biomarkers of bacterial vaginosis or precursors to vaginal dysbiosis?

Bacterial vaginosis (BV) is the most common vaginal disorder among reproductive age women. One clinical indicator of BV is a "fishy" odor. This odor has been associated with increases in several biogenic amines (BAs) that may serve as important biomarkers. Within the vagina, BA production has been linked to various vaginal taxa, yet their genetic capability to synthesize BAs is unknown. Using a bioinformatics approach, we show that relatively few vaginal taxa are predicted to be capable of producing BAs. Many of these taxa (Dialister, Prevotella, Parvimonas, Megasphaera, Peptostreptococcus, and Veillonella spp.) are more abundant in the vaginal microbial community state type (CST) IV, which is depleted in lactobacilli. Several of the major Lactobacillus species (L. crispatus, L. jensenii, and L. gasseri) were identified as possessing gene sequences for proteins predicted to be capable of putrescine production. Finally, we show in a small cross sectional study of 37 women that the BAs putrescine, cadaverine and tyramine are significantly higher in CST IV over CSTs I and III. These data support the hypothesis that BA production is conducted by few vaginal taxa and may be important to the outgrowth of BV-associated (vaginal dysbiosis) vaginal bacteria