Sediment Transport Induced by Raindrops Impacting Shallow Flows

A theory for RIFT, the transport process that results from raindrops impacting shallow flows, is presented. The theory relies on the observation that, after being lifted from the soil surface, a particle moves downstream a distance that depends on flow velocity and the time the particle remains suspended in the flow. The theory indicates that sediment transport rates increase linearly with rainfall intensity and flow velocity when entrainment by flow is absent. Laboratory experiments where sand was eroded by rain-impacted flow provide support for the theory. In addition to influencing the downstream motion of particles detached by raindrop impacts, surface-water flows absorb raindrop energy. Consequently, interactions between flow depth and drop size were also examined through the laboratory experiments. This resulted in a mathematical model of RIFT that accounts for the interactions between raindrops and flow on the sediment transport rate. When applied to experimental data, the model showed that the time-averaged effect of rainfall on sediment transport by rain-impacted flow is independent of the manner by which the rain is applied

Computational Bayesian maximum entropy solution of a stochastic advection-reaction equation in the light of site-specific information

This work presents a computational formulation of the Bayesian maximum entropy (BME) approach to solve a stochastic partial differential equation (PDE) representing the advection-reaction process across space and time. The solution approach provided by BME has some important features that distinguish it from most standard stochastic PDE techniques. In addition to the physical law, the BME solution can assimilate other sources of general and site-specific knowledge, including multiple-point nonlinear space/time statistics, hard measurements, and various forms of uncertain (soft) information. There is no need to explicitly solve the moment equations of the advection-reaction law since BME allows the information contained in them to consolidate within the general knowledge base at the structural (prior) stage of the analysis. No restrictions are posed on the shape of the underlying probability distributions or the space/time pattern of the contaminant process. Solutions of nonlinear systems of equations are obtained in four space/time dimensions and efficient computational schemes are introduced to cope with complexity. The BME solution at the prior stage is in excellent agreement with the exact analytical solution obtained in a controlled environment for comparison purposes. The prior solution is further improved at the integration (posterior) BME stage by assimilating uncertain information at the data points as well as at the solution grid nodes themselves, thus leading to the final solution of the advection-reaction law in the form of the probability distribution of possible concentration values at each space/time grid node. This is the most complete way of describing a stochastic solution and provides considerable flexibility concerning the choice of the concentration realization that is more representative of the physical situation. Numerical experiments demonstrated a high solution accuracy of the computational BME approach. The BME approach can benefit from the use of parallel processing (the relevant systems of equations can be processed simultaneously at each grid node and multiple integrals calculations can be accelerated significantly, etc.)

Study Protocol – Improving Access to Kidney Transplants (IMPAKT): A detailed account of a qualitative study investigating barriers to transplant for Australian Indigenous people with end-stage kidney disease

<p>Abstract</p> <p>Background</p> <p>Indigenous Australians are slightly more than 2% of the total Australian population however, in recent years they have comprised between 6 and 10% of new patients beginning treatment for end-stage kidney disease (ESKD). Although transplant is considered the optimal form of treatment for many ESKD patients there is a pronounced disparity between the rates at which Indigenous ESKD patients receive transplants compared with their non-Indigenous counterparts. The IMPAKT (Improving Access to Kidney Transplants) Interview study investigated reasons for this disparity through a large scale, in-depth interview study involving patients, nephrologists and key decision-making staff at selected Australian transplant and dialysis sites.</p> <p>Methods</p> <p>The design and conduct of the study reflected the multi-disciplinary membership of the core IMPAKT team. Promoting a participatory ethos, IMPAKT established partnerships with a network of hospital transplant units and hospital dialysis treatment centres that provide treatment to the vast majority of Indigenous patients across Australia. Under their auspices, the IMPAKT team conducted in-depth interviews in 26 treatment/service centres located in metropolitan, regional and remote Australia. Peer interviewing supported the engagement of Indigenous patients (146), and nephrologists (19). In total IMPAKT spoke with Indigenous and non-Indigenous patients (241), key renal nursing and other (non-specialist) staff (95) and a small number of relevant others (28). Data analysis was supported by QSR software. At each site, IMPAKT also documented educational programs and resources, mapped an hypothetical ‘patient journey’ to transplant through the local system and observed patient care and treatment routines.</p> <p>Discussion</p> <p>The national scope, inter-disciplinary approach and use of qualitative methods in an investigation of a significant health inequality affecting Indigenous people is, we believe, an Australian first. An exceptionally large cohort of Indigenous participants provided evaluative comment on their health services in relation to dialysis and transplant. Additionally, the data includes extensive parallel commentary from a cohort of specialists, nurses and other staff. The study considers a ‘patient journey’ to transplant within a diverse range of Australian treatment centre/workplace settings. The IMPAKT Interview study protocol may contribute to improvements in multi-disciplinary, flexible design health services research with hard to reach or vulnerable populations in Australia and elsewhere.</p

Ten principles relevant to health research among Indigenous Australian populations

Writing in the Journal about Indigenous health in 2011, Sir Michael Marmot suggested that the challenge was to conduct research, and to ultimately apply findings from that research, to enable Indigenous Australians to lead more flourishing lives that they would have reason to value.1 As committed Indigenous health researchers in Australia, we reflect Marmot&rsquo;s ideal &mdash; to provide the answers to key questions relating to health that might enable Indigenous Australians to live the lives that they would choose to live.As a group, we have over 120 collective years&rsquo; experience in Indigenous health research. Over this time, particularly in recent years as ethical guidelines have come into play, there have been many examples of research done well. However, as the pool of researchers is constantly replenished, we hold persisting concerns that some emerging researchers may not be well versed in the principles of best practice regarding research among Indigenous Australian populations. Implementing any research methodology among Indigenous Australian groups will work best when the following 10 principles are met. These principles are reflected in the many documents related to working and researching with Indigenous Australians; for example, the National Health and Medical Research Council (NHMRC) ethical guidelines for research among Aboriginal and Torres Strait Islander people.2 In this article, we set out these principles in one short, accessible document

Cancer testis antigen and interleukin expression correlates with survival in small bowel neuroendocrine tumors

View full abstracthttps://openworks.mdanderson.org/leading-edge/1042/thumbnail.jp

Inhibition of Striatal Soluble Guanylyl Cyclase-cGMP Signaling Reverses Basal Ganglia Dysfunction and Akinesia in Experimental Parkinsonism

There is clearly a necessity to identify novel non-dopaminergic mechanisms as new therapeutic targets for Parkinson's disease (PD). Among these, the soluble guanylyl cyclase (sGC)-cGMP signaling cascade is emerging as a promising candidate for second messenger-based therapies for the amelioration of PD symptoms. In the present study, we examined the utility of the selective sGC inhibitor 1H-[1], [2], [4] oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ) for reversing basal ganglia dysfunction and akinesia in animal models of PD.The utility of the selective sGC inhibitor ODQ for reversing biochemical, electrophysiological, histochemical, and behavioral correlates of experimental PD was performed in 6-OHDA-lesioned rats and mice chronically treated with MPTP.We found that one systemic administration of ODQ is sufficient to reverse the characteristic elevations in striatal cGMP levels, striatal output neuron activity, and metabolic activity in the subthalamic nucleus observed in 6-OHDA-lesioned rats. The latter outcome was reproduced after intrastriatal infusion of ODQ. Systemic administration of ODQ was also effective in improving deficits in forelimb akinesia induced by 6-OHDA and MPTP.Pharmacological inhibition of the sGC-cGMP signaling pathway is a promising non-dopaminergic treatment strategy for restoring basal ganglia dysfunction and attenuating motor symptoms associated with PD