Amplified erosion above waterfalls and oversteepened bedrock reaches

None of the conventional bedrock erosion laws can predict incision immediately upslope of a waterfall lip where the flow is accelerating toward a freefall. Considering the expected increase in flow velocity and shear stress at the lip of a waterfall, we determine erosion amplification at a waterfall lip as [equation], where [equation] is the erosion rate at the upstream end of the flow acceleration zone above a waterfall, Fr is the Froude number at this setting, and n ranges between 0.5–1.7. This amplification expression suggests that erosion at the lip could be as much as 2–5 times higher relative to erosion at a normal setting with identical hydraulic geometry. Utilizing this erosion amplification expression in numerical simulations, we demonstrate its impact on reach-scale morphology above waterfalls. Amplified erosion at the lip of a waterfall can trigger the formation of an oversteepened reach whose length is longer than the flow acceleration zone, provided incision wave velocity (Vi) at the upstream edge of the flow acceleration zone is higher than the retreat velocity of the waterfall face. Such an oversteepened reach is expected to be more pronounced when Vi increases with increasing slope. The simulations also suggest that oversteepening can eventually lead to steady state gradients adjacent to a waterfall lip provided Vi decreases with increasing slope. Flow acceleration above waterfalls can thus account, at least partially, for prevalent oversteepened bedrock reaches above waterfalls. Using the cosmogenic isotope Cl-36, we demonstrate that incision wave velocity upstream of a waterfall at the Dead Sea western escarpment is probably high enough for freefall-induced oversteepening to be feasible

Femoral pseudoaneurysms after percutaneous access

The femoral artery has been the primary percutaneous-based arterial access site for coronary artery catheterizations for more than three decades. Noncardiac percutaneous-based procedures have also been performed primarily with femoral access and have increased in number exponentially by vascular specialists in past decades. Groin complications are infrequent in incidence after femoral arterial access for cardiac and peripheral diagnostic and interventional cases, with groin hematomas and pseudoaneurysms being the most common. Until ultrasound-based treatment modalities became the mainstay of treatment, vascular surgeons were the primary specialty managing pseudoaneurysms, but now other specialties also manage these cases. This review outlines the clinical implications and current issues relevant to understanding the ideal treatment strategy for this common complication

Effect of Iodine on Mercury Concentrations in Dental-unit Wastewater

Dental amalgam is a mixture of mercury, silver, tin, and copper. Mercury typically makes up about 50% of it. The amalgam is used to provide the dental patient with a strong durable filling. Some of the dental amalgam may end up in the dental wastewater along with the water used for rinsing. Iodine is often used to control bacteria in dental-unit fresh waterlines. Could Iodine effect mercury concentrations in the wastewater?ISTC partnered with researchers at the Naval Institute for Dental and Biomedical Research to answer that question. Full results appear in Stone, Mark E., et al (2006). "Effect of Iodine on Mercury Concentrations in Dental-unit Wastewater." Dental Materials 22(2), 119-124. https://doi.org/10.1016/j.dental.2005.04.009.Ope

Human African Trypanosomiasis in three Malawian districts

Human African Trypanosomiasis (HAT) is a neglected tropical disease (NTD). Surveillance in many of the endemic areas is often inadequate. Up to date information on the HAT situation in Malawi, where the disease is endemic in some districts, provides opportunity to raise the profile of the disease and interest in prevention and control. A retrospective study was conducted in three Malawian districts: Nkhotakota, Rumphi and Kasungu to describe the prevalence of HAT. Hospital laboratory registers from January 2000 to December 2006 were used. The calculated annual district prevalence of Trypanonosomiasis ranged from 0.29 cases per 100,000 population in 2000, to 0.58 cases per 100,000 population in 2003. Nkhotakota District had the highest case detection rate of trypanonosomiasis of 16.56 cases per 100,000 in 2002 and the lowest rate in 2004 of 5.23 cases per 100,000. From 2004 onwards a decline in cases detected was observed. In Rumphi district the highest number of cases (17.67 cases per 100,000 population) were identified in 2003 and the lowest rate of 1.29 cases per 100,000 in 2001. The rate (17.67 cases per 100,000) found in 2003 represented a 5-fold increase of 2002 (3.02 cases per 100,000). In Kasungu the detection rate ranged from 0 per 100,000 in 2001, 2003 and 2004 to 0.99 cases per 100,000 in 2005. The number of cases in this district has remained low including in 2006, when a detection rate of 0.16 cases per 100,000 was observed.  HAT is endemic in selected districts of Malawi. There is need to explore the feasibility of active disease surveillance and the establishment of permanent preventive and control measures

Survival of Dopaminergic Amacrine Cells after Near-Infrared Light Treatment in MPTP-Treated Mice

We examined whether near-infrared light (NIr) treatment (photobiomodulation) saves dopaminergic amacrine cells of the retina in an acute and a chronic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of Parkinson disease. For the acute model, BALB/c mice had MPTP (100 mg/kg) or saline injections over 30 hours, followed by a six-day-survival period. For the chronic model, mice had MPTP (200 mg/kg) or saline injections over five weeks, followed by a three-week-survival period. NIr treatment was applied either at the same time (simultaneous series) or well after (posttreatment series) the MPTP insult. There were four groups within each series: Saline, Saline-NIr, MPTP, and MPTP-NIr. Retinae were processed for tyrosine hydroxylase (TH) immunochemistry, and cell number was analysed. In the MPTP groups, there was a significant reduction in TH+ cell number compared to the saline controls; this reduction was greater in the acute (~50%) compared to the chronic (~30%) cases. In the MPTP-NIr groups, there were significantly more TH+ cells than in the MPTP groups of both series (~30%). In summary, we showed that NIr treatment was able to both protect (simultaneous series) and rescue (posttreatment series) TH+ cells of the retina from parkinsonian insult

An analysis of likes and dislikes for history and geography of 3360 sixth grade children

Thesis (Ed.M.)--Boston Universit

Simulation of reaction diffusion processes over biologically relevant size and time scales using multi-GPU workstations

AbstractSimulation of in vivo cellular processes with the reaction–diffusion master equation (RDME) is a computationally expensive task. Our previous software enabled simulation of inhomogeneous biochemical systems for small bacteria over long time scales using the MPD-RDME method on a single GPU. Simulations of larger eukaryotic systems exceed the on-board memory capacity of individual GPUs, and long time simulations of modest-sized cells such as yeast are impractical on a single GPU. We present a new multi-GPU parallel implementation of the MPD-RDME method based on a spatial decomposition approach that supports dynamic load balancing for workstations containing GPUs of varying performance and memory capacity. We take advantage of high-performance features of CUDA for peer-to-peer GPU memory transfers and evaluate the performance of our algorithms on state-of-the-art GPU devices. We present parallel efficiency and performance results for simulations using multiple GPUs as system size, particle counts, and number of reactions grow. We also demonstrate multi-GPU performance in simulations of the Min protein system in E. coli. Moreover, our multi-GPU decomposition and load balancing approach can be generalized to other lattice-based problems

Identification of a putative man-made object from an underwater crash site using CAD model superimposition

In order to identify an object in video, a comparison with an exemplar object is typically needed. In this paper, we discuss the methodology used to identify an object detected in underwater video that was recorded during an investigation into Amelia Earhart\u27s purported crash site. A computer aided design (CAD) model of the suspected aircraft component was created based on measurements made from orthogonally rectified images of a reference aircraft, and validated against historical photographs of the subject aircraft prior to the crash. The CAD model was then superimposed on the underwater video, and specific features on the object were geometrically compared between the CAD model and the video. This geometrical comparison was used to assess the goodness of fit between the purported object and the object identified in the underwater video