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The United States Naval Academy (USNA) STEM Center for Education and Outreach addresses an urgent Navy and national need for more young people to pursue careers in STEM fields through world-wide outreach to 17,000 students and 900 teachers per year. To achieve this mission, the STEM Center has developed a hands-on and inquiry-based methodology to be used with K-12 educators at professional development workshops and with students through camps, festivals and fairs, and STEM days.According to recent data, math and computer science (CS) are the fastest growing fields among STEM careers (US Bureau of Labor Statistics, 2016). The Computer Science for All initiative (2016) urges communities to bring more computer science education into the classroom to meet the rapidly rising need for more CS graduates. As a result, the USNA STEM Center has developed a number of unplugged (without a computer) cybersecurity modules to promote engagement and increase awareness. Topic areas include encryption, networking and social media, viruses and malware, programming, hardware components, authentication and authorization, and hacking.This article describes the methodology for developing unplugged computer science activities and adapting computer science undergraduate curriculum for K-12 educators and students as an introduction to complex computer science topics.

Background: Delays in endovascular therapy can lead to worse outcomes in stroke patients. Interfacility delays when transferring patients to thrombectomy-capable hospitals are common. We sought to identify causes of such delays and create a standardized transfer process to improve transfer times. Methods: A 15-hospital system formed a multidisciplinary team to assess the current state of DIDO processes from data on previous transfers, evaluate current transfer algorithms, and analyze baseline performance. Individual hospital transfer algorithms were compared. Results: Data was analyzed for 47 patients transferred from 12 facilities to thrombectomy-capable centers from June 2017 to July 2018 who received ischemic stroke treatment. 71% were from a metro area within 50 miles of a thrombectomy-capable hospital and 29% were from outside the metro area, up to 400 miles away. 80% were transported by air by 9 different agencies. DIDO times were: 27% less than 90 min; 27% 90 to 120 min; 44% greater than 120 min. There was minimal opportunity for improvement based on: day of week, NIHSS, and treatment with alteplase. Areas for improvement include: timeliness of door to CT (x-=13 vs 35 min), time to CT read (x-=8 vs 16 min), time to alteplase (x-=48 vs 115 min), and time to transfer (x-=125 vs 148 min), time from arrival to consult with thrombectomy capable centers (x-= 53 vs 86 min), time from consult to dispatch (x-=19 vs 26 min), and time of transfer agency on scene (x-=22 vs 37 min) for metro vs rural hospitals. Conclusions: Identified causes of delays include decision to transfer and initiation of dispatch to coordinate transport. A difference in timeliness initial diagnosis and treatment of patients outside metro areas was identified. Last known well (LKW) to arrival for transferred patients revealed a need to educate sending facilities on the expanded treatment windows- only 3 patients had a LKW to arrival time greater than 4.5 hours.

Using a flexible hydrodynamic foil that pitches to produce thrust, the most pertinent aspects of a fish-like propulsion system are replicated in a controlled environment. The pitching and flexing combination creates a hydroelastic coupling in which the fluid and flexible foil simultaneously affect each other's behavior. The project investigated relationships for the propulsors’ thrust and efficiency performance to gain a better understanding of the dynamic interaction with the surrounding fluid. The analysis was conducted through reduction of the measured force and torque data. The experiments took place in a large recirculating water channel, using full span flexible propulsor models and a higher Reynolds number than previous flexible propulsor experiments. The propulsor pitched about a fixed axis at its quarter chord, with a six-axis load cell measuring the forces and torques on the shaft. The efficiency of the propulsor and the Coefficients of Thrust and Lift are presented as functions of both Strouhal Number and Stiffness Coefficient. The ensemble data will facilitate the engineering of fish-like propulsion systems for future application of this technology.

BackgroundStent retriever thrombectomy (SRT) in acute thromboembolic stroke can result in post-thrombectomy subarachnoid hemorrhage (PTSAH). Intraprocedural findings associated with PTSAH are not well defined.ObjectiveTo identify angiographic findings and procedural factors during SRT that are associated with PTSAH.Materials and methodsThis was a retrospective, observational cohort study of consecutive patients with middle cerebral artery (MCA) acute ischemic stroke treated with SRT. Inclusion criteria were: (1) age ≥18 years; (2) thromboembolic occlusion of the MCA; (3) at least one stent retriever pass beginning in an M2 branch; (4) postprocedural CT or MRI scan within 24 hours; (5) non-enhanced CT Alberta Stroke Program Early CT Score >5. Exclusion criteria included multi-territory stroke before SRT.ResultsEighty-five patients were enrolled; eight patients had PTSAH (group 1) and 77 did not (group 2). Baseline demographic and clinical characteristics were comparable between the two groups. In group 1, a significantly greater proportion of patients had more than two stent retriever passes (62.5% vs 18.2%, P=0.01), a stent retriever positioned ≥2 cm along an M2 branch (100% vs 30.2%, P=0.002), and the presence of severe iatrogenic vasospasm before SRT pass (37.5% vs 5.2%, P=0.02). One patient with PTSAH and associated mass effect deteriorated clinically.ConclusionsAn increased number of stent retriever passes, distal device positioning, and presence of severe vasospasm were associated with PTSAH. Neurological deterioration with PTSAH can occur.

The United States Navy monitors the dose its radiation workers receive using the DT-702/PD thermoluminescent dosimeter, which consists of the Harshaw 8840 holder and the four-element Harshaw 8841 card. There were two main objectives of this research. In the first objective, the dosimeters were exposed to 100 Gy using electron and x-ray beams and found to respond approximately 30-40% lower than the delivered dose. No significant effect on the under-response was found when dose rate, radiation type, dosimeter position on the phantom, and dosimeter material were varied or when the card was irradiated while enclosed in its holder. Since the current naval policy is to remove from occupational use any thermoluminescent dosimeter with an accumulated deep dose equivalent of 0.05 Sv or greater, the functionality of the dosimeter was also investigated at deep dose equivalents of 0.05, 0.15, and 0.25 Sv using 60Co and 137Cs sources as the second main objective. All dosimeters were annealed following exposure and then exposed to 5.0 mSv from a 90Sr source. In all cases, the dosimeters responded within 3% of the delivered dose, indicating that the dosimeters remained functional as defined by naval dosimetry requirements. However, the anneal time required to clear the thermoluminescent dosimeter's reading was found to increase approximately as the cube root with the delivered dose.

This project was funded by the National Oceanographic Partnership Program [National Science Foundation via the Office of Naval Research N00014-11-1-0113]. C. Spencer Garborg was supported by a Grove City College Swezey Student Fellowship to Erik Anderson. Mark Johnson was funded by a Marie Curie-Sklodowska grant from the European Union. All supplemental data files are available from the Dryad Digital Repository (doi:10.5061/dryad.4j4m1). Bio-logging tags are an important tool for the study of cetaceans, but superficial tags inevitably increase hydrodynamic loading. Substantial forces can be generated by tags on fast-swimming animals, potentially affecting behavior and energetics or promoting early tag removal. Streamlined forms have been used to reduce loading, but these designs can accelerate flow over the top of the tag. This non-axisymmetric flow results in large lift forces (normal to the animal) that become the dominant force component at high speeds. In order to reduce lift and minimize total hydrodynamic loading this work presents a new tag design (Model A) that incorporates a hydrodynamic body, a channel to reduce fluid speed differences above and below the housing and wing to redirect flow to counter lift. Additionally, three derivatives of the Model A design were used to examine the contribution of individual flow control features to overall performance. Hydrodynamic loadings of four models were compared using computational fluid dynamics (CFD). The Model A design eliminated all lift force and generated up to ~30 N of downward force in simulated 6 m/s aligned flow. The simulations were validated using particle image velocimetry (PIV) to experimentally characterize the flow around the tag design. The results of these experiments confirm the trends predicted by the simulations and demonstrate the potential benefit of flow control elements for the reduction of tag induced forces on the animal. Publisher PDF

This work was supported by NOPP with NSF funds through ONR Grant N00014-11-1-0113. MJ was supported by NOPP and the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland). MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions. Bio-logging tags are widely used to study the behavior and movements of marine mammals with the tacit assumption of little impact to the animal. However, tags on fast-swimming animals generate substantial hydrodynamic forces potentially affecting behavior and energetics adversely, or promoting early removal of the tag. In this work, hydrodynamic loading of three novel tag housing designs are compared over a range of swimming speeds using computational fluid dynamics (CFD). Results from CFD simulation were verified using tag models in a water flume with close agreement. Drag forces were reduced by minimizing geometric disruptions to the flow around the housing, while lift forces were reduced by minimizing the frontal cross-sectional area of the housing and holding the tag close to the attachment surface. Hydrodynamic tag design resulted in an experimentally measured 60% drag force reduction in 5.6 m/s flow. For all housing designs, off-axis flow increased the magnitude of the force on the tag. Experimental work with a common dolphin (Delphinus delphis) cadaver indicates that the suction cups used to attach the types of tags described here provide sufficient attachment force to resist failure to predicted forces at swimming speeds of up to 10 m/s. Publisher PDF

Cetaceans evolved flippers that are unique in both size and shape probably due to selection pressures associated with foraging and body size. Flippers function as control surfaces for maneuverability and stability. Flippers of cetaceans and engineered hydrofoils are similar with streamlined cross-sections and wing-like planforms, which affect lift, drag and hydrodynamic efficiency. Scale models of the flippers from large-bodied (body length >6 m) cetaceans (fin whale, killer whale, sperm whale) were constructed from computed tomography (CT) scans of flippers. Flipper planforms were highly tapered for the fin whale, a rounded, paddle-like design for the killer whale, and a square geometry for the sperm whale. Hydrodynamic properties of the models at varying angles of attack (–40o to 40 o ) were determined in a water tunnel with a multi-axis load cell. The flippers were found to have hydrodynamic characteristics similar to engineered wings. Differences in flipper morphology of large-bodied cetaceans and their hydrodynamic performance are associated with the requirements of aquatic locomotion involved with ecology of the whales. The flippers of the killer whale provided the greatest maneuverability, whereas the flippers of the fin whale had low drag for lunging and the flippers of the sperm whale provided lift for diving. Cetaceans are characterized by a number of common features that are associated with hydrodynamic performance for swimming. These features include a streamlined, elongate body, propulsion by oscillation of wing-like caudal flukes, lack of external hindlimbs, and forelimbs that have been modified into flippers (Fish 1998b, 2004; Thewissen 1998; Reeves et al. 2002; Woodward et al. 2006; Sanchez and Berta 2010). The flippers function hydrodynamically as control surfaces that manipulate flow to generate forces for maneuverability, stability and maintenance of trim (Fish

OBJECTIVE: The prevalence of autism spectrum disorder is steadily increasing and placing more demands on already overburdened diagnostic and treatment systems. A thoughtful, systematic reorganization of autism service delivery may reduce delays and better meet the growing need. METHODS: Two clinical centers in the Autism Intervention Research Network on Physical Health, Cincinnati Children’s Hospital Medical Center (CCHMC) and Nationwide Children’s Hospital (NCH), undertook a year-long access improvement project to reduce delays to care by using system analysis to identify sources of delay and to target changes by using a set of defined access principles. Although both sites addressed access, they focused on slightly different targets (reducing number of patients with autism spectrum disorders waiting for follow-up appointments at NCH and reducing delay to new diagnosis at CCHMC). RESULTS: Both sites achieved dramatic improvements in their complex, multidisciplinary systems. A 94% reduction in number of patients on the waitlist from 99 to 6 patients and a 22% reduction in median delay for a new ongoing care appointment were realized at NCH. A 94% reduction in third next available appointment for new physician visits for children 3 to 5 years old was realized at CCHMC. CONCLUSIONS: This article demonstrates that 2 different clinical systems improved access to care for autism diagnosis and follow-up care by identifying sources of delay and using targeted changes based on a set of access change principles. With appropriate guidance and data analysis, improvements in access can be made.

The biomimetic approach seeks technological advancement through a transfer of technology from natural technologies to engineered systems. The morphology of the wing-like flipper of the humpback whale has potential for marine applications. As opposed to the straight leading edge of conventional hydrofoils, the humpback whale flipper has a number of sinusoid-like rounded bumps, called tubercles, which are arranged periodically along the leading edge. The presence of the tubercles modifies the water flow over the wing-like surface, creating regions of vortex generation between the tubercles. These vortices interact with the flow over the tubercle and accelerate that flow, helping to maintain a partially attached boundary layer. This hydrodynamic effect can delay stall to higher angles of attack, increases lift, and reduces drag compared to the post-stall condition of conventional wings. As the humpback whale functions in the marine environment in a Reynolds regime similar to some engineered marine systems, the use of tubercles has the potential to enhance the performance of wing-like structures. Specific applications of the tubercles for marine technology include sailboat masts, fans, propellers, turbines, and control surfaces, such as rudders, dive planes, stabilizers, spoilers, and keels.

This paper presents the experimental measurement of lift and drag as well as the determination of the onset of cavitation on rudders with leading-edge protuberances (tubercles) that are operating at low to moderate Reynolds Numbers in water. The leading-edge shape used for the rudders in this study is derived from our earlier work concerning the analysis of the leading-edge morphology found on the pectoral flippers of humpback whales. While humpback whales do not swim at speeds that induce cavitation, engineered control surfaces based on this bio-inspired control surface modification might operate in cavitation conditions. This point motivates our present work to investigate the onset of cavitation on small aspect ratio rudders with tubercles. Our findings are that (i) the presence of leading-edge tubercles accelerates the onset of cavitation, (ii) the tubercles can modify the location of the onset of cavitation, (iii) the tubercle geometry has an influence on the rudder's hydrodynamic performance, (iv) for the lower Reynolds Numbers considered in this paper, the tubercles decrease lift and increase drag for angles of attack between 15 and 22 deg, (v) for angles above 22 deg, rudders with tubercles generate more lift than smooth rudders, and (vi) for the higher Reynolds Numbers investigated, the difference in performance between the smooth and tubercled rudders diminishes, suggesting the existence of a critical Reynolds Number for a given tubercle geometry beyond which tubercles have no significant effect on hydrodynamic performance.

The ability to control the flow of water around the body dictates the performance of marine mammals in the aquatic environment. Morphological specializations of marine mammals afford mechanisms for passive flow control. Aside from the design of the body, which minimizes drag, the morphology of the appendages provides hydrodynamic advantages with respect to drag, lift, thrust, and stall. The flukes of cetaceans and sirenians and flippers of pinnipeds possess geometries with flexibility, which enhance thrust production for high efficiency swimming. The pectoral flippers provide hydrodynamic lift for maneuvering. The design of the flippers is constrained by performance associated with stall. Delay of stall can be accomplished passively by modification of the flipper leading edge. Such a design is exhibited by the leading edge tubercles on the flippers of humpback whales (Megaptera novaeangliae). These novel morphological structures induce a spanwise flow field of separated vortices alternating with regions of accelerated flow. The coupled flow regions maintain areas of attached flow and delay stall to high angles of attack. The delay of stall permits enhanced turning performance with respect to both agility and maneuverability. The morphological features of marine mammals for flow control can be utilized in the biomimetic design of engineered structures for increased power production and increased efficiency.

P REVIOUS studies on increasing airfoil lift and improving stall characteristics have addressed various passive and active approaches to modifying the leading and trailing edge shapes. The passive approaches have covered such methods as rippling the trailing edge, applying serrated-edge Gurney flaps, or modifying the leading-edge (LE) profile [1,2]. Other efforts have effectively eliminated the dynamic stall of an NACA 0012 airfoil by perturbing the LE contour as little as 0.5–0.9%of the chord [3]. Levshin et al. [4] demonstrated that sinusoidal LE planforms on an NACA 63-021 airfoil section decreased maximum lift, but extended the stall angle by almost 9 deg. The larger amplitude sinusoids created “softer” stall characteristics by maintaining attached flow at the peaks despite separated flow in the troughs. These tests were performed to simulate the effects of LE tubercles on humpback whale (Megaptera novaeangliae) flippers. Prior work by the authors also reported wind tunnel measurements for idealized scale models of humpback whale flippers [5]. One model had a smooth leading edge and a secondmodel had sinusoidal bumps (tubercles) along the leading edge for the outer 2 3 of the span. It was found that the addition of tubercles to a 3-D idealized flipper increased the maximum lift coefficient while reducing the drag coefficient over a portion of the operational envelope. It is thought that the tubercles on the flipper leading-edge enhance the whale’s ability to maneuver to catch prey [6]. Though the work to date regarding sinusoidal or serrated leading-edge planforms is largely motivated by marine mammal locomotion, the effects of extending the stall point for lifting surfaces at similar Reynolds numbers (Re) may have application to small-UAV (unmanned aerial vehicle) design and the inevitable laminar stall problems [7]. However other relevant applications might benefit from the effects of simulated tubercles such as stall alleviation/separation control on sailboat centerboards or wind turbines, where an expanded operating envelope could improve the overall effectiveness of the blade [8,9]. In the present work, a better understanding is sought of the mechanism of the improvements measured in previous experiments, with a greater applicability in mind. The authors seek to determine whether the performance improvements resulted from enhancements to the sectional characteristics of wings with tubercles (i.e., essentially 2-D effects), or from Reynolds number effects on a tapered planform, or from other 3-D effects such as spanwise stall progression.

The humpback whale (Megaptera novaeangliae) is exceptional among the baleen whales in its ability to undertake acrobatic underwater maneuvers to catch prey. In order to execute these banking and turning maneuvers, humpback whales utilize extremely mobile flippers. The humpback whale flipper is unique because of the presence of large protuberances or tubercles located on the leading edge which gives this surface a scalloped appearance. We show, through wind tunnel measurements, that the addition of leading-edge tubercles to a scale model of an idealized humpback whale flipper delays the stall angle by approximately 40%, while increasing lift and decreasing drag.

Access to health care, the timely use of personal health services to achieve the best possible health outcomes, remains a fundamental problem for children in the United States. To date, research and interventions addressing children’s access to care have largely focused on policy-level features of the health care system (such as health insurance and geographic availability of providers) with some, although limited, success. Ultimately, access to health care implies entry into the health care system. Practice scheduling systems are the point of entry to primary care health services for children and thus directly determine access to care in pediatric and family medicine practices. Here we explore the rationale for improving access to care for children from an additional angle: through improving practice scheduling systems. It is our hypothesis that some of the most promising contemporary interventions to improve children’s access involve improving primary care scheduling systems. These approaches should complement successful policy-level interventions to improve access to care for children.

We study the propulsive dynamics of a thin foil pitching about its quarter chord and allowed to passively plunge. Specifically, we focus on the effect of variations in translational spring stiffness on propulsor plunge and on the minimum oscillation frequency required to produce positive thrust. Our numerical simulation utilizes a two-dimensional hydroelasticity model of the propulsor–fluid system in a constant velocity free stream. The pitch is forced at the quarter chord by a drive shaft and the dynamics of the fluid–structure interaction coupled to the strength of a translational spring determines the plunge amplitude. We use an unsteady two-dimensional vortex lattice method to model the hydrodynamics of the propulsor producing thrust in a potential flow field. The phase relationship between the driving angle and the plunge displacement is discussed, along with the effects of changing spring stiffness on thrust and efficiency. We show that passive plunge reduces the critical frequency for positive thrust production. This allows simple one-actuator input to compete with more complicated two-actuator systems.

Abstract —The genetic analysis of hypertension has revealed complex and inconsistent results, making it difficult to draw clear conclusions regarding the impact of specific genes on blood pressure regulation in diverse human populations. Some of the confusion from previous studies is probably due to undetected gene-gene interactions. Instead of focusing on the effects of single genes on hypertension, we examined the effects of interactions of alleles at 4 candidate loci. Three of the loci are in the renin-angiotensin-system, angiotensinogen, ACE, and angiotensin II type 1 receptor, and they have been associated with hypertension in at least 1 previous study. The fourth locus studied is a previously undescribed locus, named FJ. In total, 7 polymorphic sites at these loci were analyzed for their association with hypertension in 51 normotensive and 126 hypertensive age-matched individuals. There were no significant differences between the 2 phenotypic classes with respect to either allele or genotype frequencies. However, when we tested for nonallelic associations (linkage disequilibrium), we found that of the 120 multilocus comparisons, 16 deviated significantly from random in the hypertensive class, but there were no significant deviations in the normotensive group. These findings suggest that genetic interactions between multiple loci rather than variants of a single gene underlie the genetic basis of hypertension in our study subjects. We hypothesize that such interactions may account for the inconsistent findings in previous studies because, unlike our study, prior studies almost always examined single-locus effects and did not consider the effects of variation at other potentially interacting loci.

Purpose: Current literature has limited information on the natural history of the stroke cohort eligible for mechanical thrombectomy. The placebo group from the PROACT II study is often used as a historical control, despite differences in entry criteria. Reported herein are data in a stroke cohort eligible for mechanical thrombectomy but untreated due to unavailability or inability to initiate endovascular treatment within the 8-hr window due to delayed presentation. The goal is to compare the functional independence rate with the PROACT placebo group. Methods: The FIRST Trial is a prospective, multicenter, natural history study of a stroke cohort eligible for but untreated by mechanical thrombectomy presenting within 8 hrs of symptom onset from a large vessel occlusion and a NIHSS of at least 10. The primary endpoint is functional outcome at 90 days as defined by a mRS 0-2. Results are reported from an interim analysis. Results: Fifty-nine (59) patients were enrolled and met study criteria for this interim analysis. The mean age was 68.2 ± 17 years; median NIHSS was 18 (5-34). Target vessel occlusions were in the ICA (35.7%), MCA (60.7%), and other (3.6%). At admission, the TIMI 0-1 rate was 89% (49/55), and the TICI 0-1 rate was 89% (48/54). Of these, only 10% (3/30) showed spontaneous recanalization (TIMI 2-3 or TICI 2a-3). Eleven of 55 (20%) patients achieved a good 90-day outcome, and 24 of 59 (40.7%) died. The serious adverse event rate was 52.6% (30/57), including respiratory failure (8 cases) and pneumonia (4 cases). A total of 6 (10%) patients suffered intracerebral hemorrhage (ICH). Below is a comparison of the MCA cohort vs. PROACT II placebo patients. Conclusion: Compared with PROACT II placebo patients, the stroke cohort eligible for mechanical thrombectomy who were untreated have a lower rate of recanalization and worse outcome. These results indicate it may not be appropriate to use the PROACT placebo patients as historical controls for mechanical thrombectomy trials.

Biology is a source of inspiration for many functional aspects of engineered systems. Fish can provide guidance for the design of animal-like robots, which have soft elastic bodies that are a continuum of actuator, sensor, and information processor. Fish respond to minute pressure changes in water, generating thrust and gaining lift from obstacles in the current, altering the shape of body and fins and using sensory nerves in their muscles to control them. Dielectric Elastomer (DE) artificial muscles offer a mechanism for a fish muscle actuator. DE devices have already been shown to outperform natural muscle in terms of active stress, strain, and speed[1-3]. DE's also have multi-functional capabilities that include actuation, sensing, logic and even energy harvesting, all achievable through appropriate control of charge[4, 5]. But DE actuators must be designed so that they provide enough torque to drive the tail and develop useful forward thrust.

When radiolabeled precursors and autoradiography are used to investigate turnover of protein components in photoreceptive cone outer segments (COSs), the labeled components—primarily visual pigment molecules (opsins)—are diffusely distributed along the COS. To further assess this COS labeling pattern, we derive a simplified mass-transfer model for quantifying the contributions of advective and diffusive mechanisms to the distribution of opsins within COSs of the frog retina. Two opsin-containing regions of the COS are evaluated: the core axial array of disks and the plasmalemma. Numerical solutions of the mass-transfer model indicate three distinct stages of system evolution. In the first stage, plasmalemma diffusion is dominant. In the second stage, the plasmalemma density reaches a metastable state and transfer between the plasmalemma and disk region occurs, which is followed by an increase in density that is qualitatively similar for both regions. The final stage consists of both regions slowly evolving to the steady-state solution. Our results indicate that autoradiographic and cognate approaches for tracking labeled opsins in the COS cannot be effective methodologies for assessing new disk formation at the base of the COS.

The addition of protuberances, inspired by the humpback whale flipper, on the leading edge of lift producing foils has been shown to improve hydrodynamic performance under a certain range of flow conditions. Specifically, finite wing models have displayed delayed stall characteristics at higher angles of attack and increased maximum lift coefficients without significant hydrodynamic penalties. The objective of this project was to investigate the impact that leading edge protuberances (i.e. tubercles) have on the effectiveness of marine tidal turbine blades, especially at lower tidal flow speeds. The experimental results obtained utilizing three different blade designs (baseline and two tubercle modified) are compared. All blades were designed with a 3-D computer aided design software package and manufactured utilizing rapid prototype techniques. The tests were conducted in the 120 ft tow tank at the U.S. Naval Academy using an experimental apparatus that measured flow speed and electrical power generated. Results for power coefficients are presented for a range of tip speed ratios. Cut-in velocity was also used to evaluated the blade designs. For all test criteria, the tubercle modified blades outperformed the smooth leading edge baseline design blades at the lower test velocities, and did not show degraded performance at the higher velocities tested.Copyright © 2011 by ASME

When a phenomenon in nature is mimicked for practical applications, it is often done so in an idealized fashion, such as representing the shape found in nature with convenient, piece-wise smooth mathematical functions. The aim of idealization is to capture the advantageous features of the natural phenomenon without having to exactly replicate it, and it is often assumed that the idealization process does in fact capture the relevant geometry. We explored the consequences of the idealization process by creating exact scale models of cetacean flippers using CT scans, creating corresponding idealized versions and then determining the hydrodynamic characteristics of the models via water tunnel testing. We found that the majority of the idealized models did not exhibit fluid dynamic properties that were drastically different from those of the real models, although multiple consequences resulting from the idealization process were evident. Drag performance was significantly improved by idealization. Overall, idealization is an excellent way to capture the relevant effects of a phenomenon found in nature, which spares the researcher from having to painstakingly create exact models, although we have found that there are situations where idealization may have unintended consequences such as one model that exhibited a decrease in lift performance.

SUMMARYCetaceans (whales, dolphins and porpoises) have evolved flippers that aid in effective locomotion through their aquatic environments. Differing evolutionary pressures upon cetaceans, including hunting and feeding requirements, and other factors such as animal mass and size have resulted in flippers that are unique among each species. Cetacean flippers may be viewed as being analogous to modern engineered hydrofoils, which have hydrodynamic properties such as lift coefficient, drag coefficient and associated efficiency. Field observations and the collection of biological samples have resulted in flipper geometry being known for most cetacean species. However,the hydrodynamic properties of cetacean flippers have not been rigorously examined and thus their performance properties are unknown. By conducting water tunnel testing using scale models of cetacean flippers derived via computed tomography (CT) scans, as well as computational fluid dynamic (CFD) simulations, we present a baseline work to describe the hydrodynamic properties of several cetacean flippers. We found that flippers of similar planform shape had similar hydrodynamic performance properties. Furthermore, one group of flippers of planform shape similar to modern swept wings was found to have lift coefficients that increased with angle of attack nonlinearly, which was caused by the onset of vortex-dominated lift. Drag coefficient versus angle of attack curves were found to be less dependent on planform shape. Our work represents a step towards the understanding of the association between performance, ecology, morphology and fluid mechanics based on the three-dimensional geometry of cetacean flippers.

A convective heat transfer enhancement technique and the experimental methods used to quantify the improvement in heat transfer and subsequent differential pressure are introduced. The enhancement technique employed time varying magnetic fields produced in a pipe to cause the ferromagnetic particles of a particle laden fluid (mineral oil and iron filings) to be attracted to and released from a heated pipe wall. The ferromagnetic particles acted not only to advect heat from the pipe wall into the bulk fluid but they also significantly modified the flow field, disrupted the boundary layer, allowed cooler fluid to reach the high temperature pipe wall, increased thermal energy transfer directly to the fluid, and contributed to the overall improvement in heat transfer rate. The experimental method utilized to quantify an increased effectiveness of convective heat transfer used an apparatus designed to replicate an internally cooled fin, whose surface temperature was measured with an IR camera. These temperature measurements were utilized to calculate the convective heat transfer coefficient (h) of the fluid within the pipe. The enhancement technique demonstrated a 267% increase in heat transfer coefficient with only a corresponding 48% increase in flow differential pressure for an electromagnetic switching frequency of 2 Hz. It is also found that there were optimum magnetic field switching frequencies for both enhancement and differential pressure magnitudes.

A convective heat transfer enhancement technique and the experimental method used to quantify the improvement in heat transfer are introduced. The enhancement technique employs time varying magnetic fields produced in a pipe to cause the ferromagnetic particles of a particle laden fluid (mineral oil and iron filings) to be attracted to and released from the pipe wall. The magnetic field remains energized long enough to attract particles to the wall and allow the heat to be quickly transferred to the highly thermally conductive particles. The released particles utilize their large surface area when dispersed to efficiently transfer heat to the bulk fluid. The ferromagnetic particles act not only to advect heat into the bulk fluid, but they also disrupt the boundary layer, allowing cooler fluid to reach the high temperature pipe wall, increase thermal energy transfer directly to the fluid and contribute to the overall improvement in heat transfer rate. The experimental method utilized to quantify increased effectiveness of convective heat transfer uses an experimental apparatus designed to replicate an internally cooled fin. The pipe test section acts as an internally cooled fin whose surface temperature is measured with an IR camera. These temperature measurements are then utilized to calculate the convective heat transfer coefficient (h) of the fluid within the pipe. The enhancement technique demonstrated a 250% increases in heat transfer coefficient for the experimental parameters tested.Copyright © 2007 by ASME

Objective.Appointment delays impede access to primary health care. By reducing appointment delays, open access (OA) scheduling may improve access to and the quality of primary health care. The objective of this pilot study was to assess the potential impact of OA on practice and patient outcomes by using pilot-study data from 4 North Carolina primary care practices.Methods.We conducted an interrupted time-series pilot study of 4 North Carolina primary care practices (2 family medicine and 2 pediatric practices) participating in a quality-improvement (QI) collaborative from May 2001 to May 2002. The year-long collaborative comprised 25 practices and consisted of three 2-day meetings led by expert faculty, monthly data feedback, and monthly conference calls. Our main outcome measures were appointment delays, appointment no-shows, patient satisfaction, continuity of care, and staff satisfaction during the 12-month study period.Results.Providers in all 4 practices successfully implemented OA. On average, providers reduced their delay to the third available preventive care appointment from 36 to 4 days. No-show rates declined (first quarter [Q1] rate: 16%; fourth quarter [Q4] rate: 11%; no-show reduction: 5% [95% confidence interval: 1%, 10%]), and overall patient satisfaction improved (Q1: 45% rated overall visit quality as excellent; Q4: 61% rated overall visit quality as excellent; change in satisfaction: 16% [95% confidence interval: 0.2%, 30%]). Continuity of care followed a similar pattern of improvement, but the change was not statistically significant. Staff satisfaction neither improved nor declined.Conclusions.This pilot study suggests that primary care practices can implement OA successfully by using QI-collaborative methods. These results provide preliminary evidence that OA may improve practice and patient outcomes in primary care. These analyses should be repeated in larger groups of practices with longer follow-up.

From Kooyman’s 1963 wind-up kitchen timer TDR, multi-sensor tags have evolved significantly over the last twenty years. These advancements, including high fidelity acoustics, have been driven by improved sensing and electronics technology, and resulted in highly integrated mechatronics systems for the study of free ranging animals. In the next decade, these tags will continue to improve, and promising work has begun in three key areas: (i) new sensors; (ii) expanding uses of existing sensors; and (iii) increasing attachment duration and reliability. The addition of rapid acquisition GPS and the inclusion of gyroscopes to separate the dynamic acceleration of the animal from gravitational acceleration, are underway but not widely available to the community. Existing sensors could be used for more and different applications, e.g., measuring ambient ocean noise. Tags attached to pinnipeds in the Southern Ocean, for example, could provide noise measurements from remote areas. Finally, attachment duration has been limiting for cetaceans because the suction cups typically used do not reliably stay attached for more than a day. We will present data on engineering efforts to improve attachments: (i) improved tag hydrodynamics; (ii) incorporating bio-compatible glues; and (iii) micro structuring tag components to utilize hydrostatic forces and enhance adhesion.

Introduction/Purpose Current literature has only limited information on the natural history of the stroke cohort eligible for mechanical thrombectomy. This has contributed to the uncertainties over the benefits of mechanical thrombectomy devices since they were approved either by single arm trials or with another device as active control. The aim of FIRST is to gather real world control data to reference results from mechanical thrombectomy trials in the proper context. Materials and Methods The FIRST Trial is a prospective, multicentre, single arm natural history study of a stroke cohort eligible for but untreated by endovascular therapy presenting within 8 hours of symptom onset from a large vessel occlusion and a NIHSS score ≥10. Patients should be ineligible or refractory to lytic therapy. The primary endpoint is 90-day functional outcome as defined by a mRS 0–2. Results For this interim analysis, 61 enrolled patients met study criteria. The mean age was 67.7 ± 15.7 years; median NIHSS score was 18 (IQR14–22). Target vessel occlusions were located in the ICA (28%), MCA (67%), and other (5%). At admission, the TIMI 0–1 rate was 98% (59/60), and the TICI 0–1 rate was 98% (58/59). Of these, only 10% (4/41) and 12% (5/41) showed spontaneous recanalisation (TIMI 2–3 or TICI 2a-3). Twelve of 54 (22%) patients achieved a good 90-day outcome, and 25 of 61 (41%) died. The serious adverse event rate within 24 hours of stroke onset was 54% (33/61), including cerebral oedema (8 cases) and respiratory failure (4 cases). Eleven (18%) patients suffered intracerebral haemorrhage. 33 (56%) were refractory to IV rtPA. Compared with PROACT II placebo patients, the stroke cohort eligible for mechanical thrombectomy who were untreated have different baseline characteristics, a lower recanalisation rate, and worse outcome. The graph shows a comparison of 90-day good outcome in the FIRST vs Penumbra System Trials, trichotomised by pre-ASPECTS scores. Conclusion Large vessel acute ischaemic stroke is a malignant disease wherein 78% of patients will either die or suffer long-term disabilities if untreated. When compared to the same stroke cohort without treatment, IA intervention with the Penumbra System consistently showed treatment effects. There are substantial differences in entry criteria and clinical outcomes between the FIRST and PROACT 2 patient populations. These results suggest it is not appropriate to use the PROACT placebo patients as historical controls for mechanical thrombectomy trials. FIRST data may serve as a benchmark for future trials. Disclosures V. Janardhan: None. L. Carlson: None. R. Gianatasio: None. S. Chen: None. P. Bhuva: None. M. Murray: None. M. Vijayappa: None. P. Hansen: None. R. Cheung: None. T. Leung: None. I. Grunwald: 6; C; Penumbra, Inc. H. Hernandez: 5; C; Penumbra, Inc. L. Barraza: 5; C; Penumbra, Inc. H. Buell: 5; C; Penumbra, Inc. S. Kuo: 5; C; Penumbra, Inc. A. Bose: 4; C; Penumbra, Inc. 5; C; Penumbra, Inc. S. Sit: 4; C; Penumbra, Inc. 5; C; Penumbra, Inc.

The principal neutralization determinant (PND) of human immunodeficiency virus type 1 envelope glycoprotein gp120 contains a conserved GPG sequence. The effects of a 29-amino-acid deletion of most of the PND, a 3-amino-acid deletion in the GPG sequence, and 16 single-amino-acid substitutions in the GPG sequence were determined in a transient expression assay. All mutant envelope glycoproteins were expressed at levels comparable to that of the wild-type envelope, and mutations in the GPG sequence did not affect processing to gp120 or, except for the 29-amino-acid deletion, binding to CD4. Of all of the mutants, only the GHG and GFG mutants induced formation of syncytia similar in size and number to those induced by the wild-type envelope. When the envelope expression level was increased 10-fold or more, several additional mutants (APG, GAG, GSG, GQG, GVG, and GPF) also induced syncytium formation. Transfection with infectious proviral molecular clones containing the GHG, GFG, APG, GAG, GSG, or GPF mutations induced production of viral particles; however, only the GPG, GHG, and GFG viruses produced active infections in CD4-bearing cells. Furthermore, whereas the wild-type virus was efficiently neutralized by PND polyclonal and monoclonal antibodies, the GHG- and GFG-containing viruses were not. These results show that mutations in the GPG sequence found within the PND do not affect envelope expression and do not significantly affect CD4 binding or production of viral particles but that they do affect the ability of the envelope to induce syncytia and those of the viral particles to infect CD4 cells and be neutralized by PND antibodies.