Effects of Shoal Margin Collapses on the Morphodynamics of a Sandy Estuary

Shoal margin collapses of several million cubic meters have occurred in the Western Scheldt estuary, the Netherlands, on average five times a year over the last decades. While these collapses involve significant volumes of material, their effect on the channel-shoal morphology is unknown. We hypothesize that collapses dynamicize the channel-shoal interactions, which could impact the ecological functioning, flood safety, and navigation in the estuary. The objective is to investigate how locations, probability, type, and volume of shoal margin collapse affect the channel-shoal dynamics. We implemented an empirically validated parameterization for shoal margin collapses and tested its effect on simulated estuary morphological development in a Delft3D schematization of the Western Scheldt. Three sets of scenarios were analyzed for near-field and far-field effects on flow pattern and channel-shoal morphology: (1) an observed shoal margin collapse of 2014, (2) initial large collapses on 10 locations, and (3) continuous collapses predicted by our novel probabilistic model over a time span of decades. Results show that a single shoal margin collapse only affects the local dynamics in the longitudinal flow direction and dampen out within a year for typical volumes, whereas larger disturbances that reach the seaward or landward sill at tidal channel junctions grow. The direction of the strongest tidally averaged flow determined the redistribution of the collapsed sediment. We conclude that adding the process of shoal margin collapses increases the channel-shoal interactions and that in intensively dredged estuaries shoal margins oversteepen, amplifying the number of collapses, but because of dredging the natural morphological response is interrupted

Tissue Culture of Secondary Xylem Parenchyma of Four Species of Southern Pines

Callus was grown from increment core explants of longleaf pine (Pinus palustris Mill.), slash pine (P. elliottii Engelm.), loblolly pine (P. taeda L.), and shortleaf pine (P. echinata Mill.) trees that had 30-45 annual rings of sapwood. Callus emanated from vertical and horizontal resin canals and uniserate rays. It originated from epithelial cells and longitudinal and ray parenchyma cells. There was relatively little difference in the amount of callus produced from the outer to inner sapwood of longleaf and slash pines compared to the reduction that occurred in loblolly and shortleaf pines. Production was generally lower in the transition zone, especially in loblolly and shortleaf pines, and virtually nonexistent in the heartwood. Several current theories of heartwood formation are discussed in light of the results

The Human-Robot Interaction Operating System

In order for humans and robots to work effectively together, they need to be able to converse about abilities, goals and achievements. Thus, we are developing an interaction infrastructure called the "Human-Robot Interaction Operating System" (HRI/OS). The HRI/OS provides a structured software framework for building human-robot teams, supports a variety of user interfaces, enables humans and robots to engage in task-oriented dialogue, and facilitates integration of robots through an extensible API

Measurement and monitoring of electrocardiogram belt tension in premature infants for assessment of respiratory function

Background: Monitoring of the electrocardiogram (ECG) in premature infants with conventional adhesive-backed electrodes can harm their sensitive skin. Use of an electrode belt prevents skin irritation, but the effect of belt pressure on respiratory function is unknown. A strain gauge sensor is described which measures applied belt tension. Method: The device frame was comprised of an aluminum housing and slide to minimize the device weight. Velcro tabs connected housing and slide to opposite tabs located at the electrode belt ends. The slide was connected to a leaf spring, to which were bonded two piezoresistive transducers in a half-bridge circuit configuration. The device was tested for linearity and calibrated. The effect on infant respiratory function of constant belt tension in the normal range (30 g–90 g) was determined. Results: The mechanical response to a step input was second order (f_n = 401 Hz, ζ = 0.08). The relationship between applied tension and output voltage was linear in the range 25–225 gm of applied tension (r² = 0.99). Measured device sensitivity was 2.18 mV/gm tension using a 5 V bridge excitation voltage. When belt tension was increased in the normal range from 30 gm to 90 gm, there was no significant change in heart rate and most respiratory functions during monitoring. At an intermediate level of tension of 50 gm, pulmonary resistance and work of breathing significantly decreased. Conclusion: The mechanical and electrical design of a device for monitoring electrocardiogram electrode belt tension is described. Within the typical range of application tension, cardiovascular and respiratory function are not substantially negatively affected by electrode belt force

Coordinate Frames in Robotic Teleoperation

Abstract—An important mode of human-robot interaction is teleoperation, in which a human operator directly controls a robot via hardware such as a joystick or mouse. Such control is not always easy, however, as the viewpoint of the human, the alignment of the input device, and the local coordinate frame of the robot are rarely all aligned. These discrepancies force the user to reconcile the involved coordinate frames during teleoperation. Therefore, the choice of coordinate frames is critical since an unintuitive coordinate frame mapping will likely lead to higher mental workload and reduced efficiency. We discuss this concern, describe the various difficulties involved with natural remote teleoperation of a robot, and report experiments that demonstrate the effects of using different frames of reference on task performance and user mental workload. I

Diffusion theory and knowledge dissemination, utilization and integration

Many accomplishments of public health have been distributed unevenly among populations. This article reviews the concepts of applying evidence-based practice in public health in the face of the varied cultures and circumstances of practice in these varied populations. Key components of EBPH include: making decisions based on the best available scientific evidence, using data and information systems systematically, applying program planning frameworks, engaging the community and practitioners in decision making, conducting sound evaluation, and disseminating what is learned. The usual application of these principles has overemphasized the scientific evidence as the starting point, whereas this review suggests engaging the community and practitioners as an equally important starting point to assess their needs, assets and circumstances, which can be facilitated with program planning frameworks and use of local assessment and surveillance data

The EvoDevoCI: A Concept Inventory for Gauging Students’ Understanding of Evolutionary Developmental Biology

The American Association for the Advancement of Science 2011 report Vision and Change in Undergraduate Biology Education encourages the teaching of developmental biology as an important part of teaching evolution. Recently, however, we found that biology majors often lack the developmental knowledge needed to understand evolutionary developmental biology, or “evo-devo.” To assist in efforts to improve evo-devo instruction among undergraduate biology majors, we designed a concept inventory (CI) for evolutionary developmental biology, the EvoDevoCI. The CI measures student understanding of six core evo-devo concepts using four scenarios and 11 multiple-choice items, all inspired by authentic scientific examples. Distracters were designed to represent the common conceptual difficulties students have with each evo-devo concept. The tool was validated by experts and administered at four institutions to 1191 students during preliminary (n = 652) and final (n = 539) field trials. We used student responses to evaluate the readability, difficulty, discriminability, validity, and reliability of the EvoDevoCI, which included items ranging in difficulty from 0.22–0.55 and in discriminability from 0.19–0.38. Such measures suggest the EvoDevoCI is an effective tool for assessing student understanding of evo-devo concepts and the prevalence of associated common conceptual difficulties among both novice and advanced undergraduate biology majors

The EvoDevoCI: A Concept Inventory for Gauging Students’ Understanding of Evolutionary Developmental Biology

The American Association for the Advancement of Science 2011 report Vision and Change in Undergraduate Biology Education encourages the teaching of developmental biology as an important part of teaching evolution. Recently, however, we found that biology majors often lack the developmental knowledge needed to understand evolutionary developmental biology, or “evo-devo.” To assist in efforts to improve evo-devo instruction among undergraduate biology majors, we designed a concept inventory (CI) for evolutionary developmental biology, the EvoDevoCI. The CI measures student understanding of six core evo-devo concepts using four scenarios and 11 multiple-choice items, all inspired by authentic scientific examples. Distracters were designed to represent the common conceptual difficulties students have with each evo-devo concept. The tool was validated by experts and administered at four institutions to 1191 students during preliminary (n = 652) and final (n = 539) field trials. We used student responses to evaluate the readability, difficulty, discriminability, validity, and reliability of the EvoDevoCI, which included items ranging in difficulty from 0.22–0.55 and in discriminability from 0.19–0.38. Such measures suggest the EvoDevoCI is an effective tool for assessing student understanding of evo-devo concepts and the prevalence of associated common conceptual difficulties among both novice and advanced undergraduate biology majors