Hemichordates as a model system for investigating intertidal zonation in soft sediments

Intertidal zonation of organisms is well studied on rocky shores but less so in soft sediment communities. On rocky shores, biotic factors such as predation often set the lower bound of a zone, while abiotic factors set the upper bound. Here I describe the zonation of hemichordate worms at two field sites in Maine and Virginia. In Virginia, Saccoglossus kowalevskii occurs in the mid-intertidal zone at densities up to 500 m-2. In Maine, two hemichordate species, Saccoglossus bromophenolosus and Protoglossus graveolens, co-occur at densities approaching 100 m-2. Hemichordates have chemical defenses that appear to deter fish, but not crustacean, predators. Six species of crustaceans and two species of predatory polychaetes were fed all three species of hemichordate. Crustaceans readily consumed hemichordates, while the polychaetes did not. In predator choice experiments, hermit crabs preferred hemichordates over the tissue of blue mussels, while green crabs preferred mussel tissue. These results suggest that, consistent with the rocky intertidal paradigm, the lower bound of the hemichordate zone could be set by crustacean predators, at least some of which appear to prefer hemichordates over palatable alternatives

Allosteric modulators targeting CNS muscarinic receptors

Muscarinic acetylcholine receptors are G protein-coupled receptors (GPCRs) which are broadly expressed in the central nervous system (CNS) and other tissues in the periphery. They emerge as important drug targets for a number of diseases including Alzheimer's disease, Parkinson's disease, and schizophrenia. Muscarinic receptors are divided into five subtypes (M1-M5) of which M1-M4 have been crystalized. All subtypes possess at least one allosteric binding site which is located in the extracellular region of the receptor on top of the ACh (i.e. orthosteric) binding site. The former can be specifically targeted by chemical compounds (mostly small molecules) and binding of such allosteric modulators affects the affinity and/or efficacy of orthosteric ligands. This allows highly specific modulation of GPCR function and, from a drug discovery point of view, may be advantageous in terms of subtype selectivity and biased signaling. There is a plethora of allosteric modulators for all five muscarinic receptor subtypes. This review presents the basic principles of allosteric modulation of GPCRs on both the molecular and structural level focusing on allosteric modulators of the muscarinic receptor family. Further we discuss dualsteric (i.e. bitopic orthosteric/allosteric) ligands emphasizing their potential in modulating muscarinic receptor dynamics and signaling. The common mechanisms of muscarinic receptor allosteric modulation have been proven to be generalizable and are at play at many, if not all GPCRs. Given this paradigmatic role of muscarinic receptors we suggest that also new developments in muscarinic allosteric modulation may also be extended to other members of the GPCR superfamily

Methodology development for evaluation of selective-fidelity rotorcraft simulation

This paper addressed the initial step toward the goal of establishing performance and handling qualities acceptance criteria for realtime rotorcraft simulators through a planned research effort to quantify the system capabilities of 'selective fidelity' simulators. Within this framework the simulator is then classified based on the required task. The simulator is evaluated by separating the various subsystems (visual, motion, etc.) and applying corresponding fidelity constants based on the specific task. This methodology not only provides an assessment technique, but also provides a technique to determine the required levels of subsystem fidelity for a specific task

Aviation technology research plan rotary wing program development and evaluation of performance

Issued as Progress reports [nos. 1-2], and Final report, Project no. E-16-M08Final report has title: Aviation technology research plan rotary wing program development and evaluation of performanceFinal report has co-author: J.V.R. Prasa

Scalar Representation and Conjugation of Set-Valued Functions

To a function with values in the power set of a pre-ordered, separated locally convex space a family of scalarizations is given which completely characterizes the original function. A concept of a Legendre-Fenchel conjugate for set-valued functions is introduced and identified with the conjugates of the scalarizations. Using this conjugate, weak and strong duality results are proven.Comment: arXiv admin note: substantial text overlap with arXiv:1012.435

TrueGrid: Code the table, tabulate the data

Spreadsheet systems are live programming environments. Both the data and the code are right in front you, and if you edit either of them, the effects are immediately visible. Unfortunately, spreadsheets lack mechanisms for abstraction, such as classes, function definitions etc. Programming languages excel at abstraction, but most mainstream languages or integrated development environments (IDEs) do not support the interactive, live feedback loop of spreadsheets. As a result, exploring and testing of code is cumbersome and indirect. In this paper we propose a method to bring both worlds closer together, by juxtaposing ordinary code and spreadsheet-like grids in the IDE, called TrueGrid. Using TrueGrid spreadsheet cells can be programmed with a fully featured programming language. Spreadsheet users then may enjoy benefits of source code, including added abstractions, syntax highlighting, version control, etc. On the other hand, programmers may leverage the grid for interactive exploring and testing of code. We illustrate these benefits using a prototype implementation of True- Grid that runs in the browser and uses Javascript as a programming language

Systematic Review: The Effects of Nonpharmacological and Pharmacological Measures in Neonates with Neonatal Abstinence Syndrome

With the increasing incidence of drug addiction among pregnant women, neonatal abstinence syndrome (NAS) has become a significant problem in the United States and has led to increased hospital costs, longer lengths of stay, and more serious health problems in neonates. This systematic review will explore the evidence about outcome differences for neonates with NAS that receive breastfeeding, rooming-in, and acupuncture in addition to pharmacological agents when compared to infants only receiving pharmacological agents. Twenty-one articles, retrieved from the databases PubMed and CINAHL and published between the years 2000-2017, were described in an integrated review, analyzed with critical appraisal, and synthesized for this systematic review. In general, researchers have found that breastfeeding, rooming-in, and acupuncture have positive effects of decreasing the need for pharmacological treatment, NAS symptoms, hospital costs, and length of hospital stay for infants with NAS when used in conjunction with pharmacologic agents

SRPT Scheduling for Web Servers

This note briey summarizes some results from two papers: [4] and [23]. These papers pose the following question: Is it possible to reduce the expected response time of every request at a web server, simply by changing the order in which we schedule the requests? In [4] we approach this question analytically via an M/G/1 queue. In [23] we approach the same question via implementation involving an Apache web server running on Linux

Evaporation of Lennard-Jones Fluids

Evaporation and condensation at a liquid/vapor interface are ubiquitous interphase mass and energy transfer phenomena that are still not well understood. We have carried out large scale molecular dynamics simulations of Lennard-Jones (LJ) fluids composed of monomers, dimers, or trimers to investigate these processes with molecular detail. For LJ monomers in contact with a vacuum, the evaporation rate is found to be very high with significant evaporative cooling and an accompanying density gradient in the liquid domain near the liquid/vapor interface. Increasing the chain length to just dimers significantly reduces the evaporation rate. We confirm that mechanical equilibrium plays a key role in determining the evaporation rate and the density and temperature profiles across the liquid/vapor interface. The velocity distributions of evaporated molecules and the evaporation and condensation coefficients are measured and compared to the predictions of an existing model based on kinetic theory of gases. Our results indicate that for both monatomic and polyatomic molecules, the evaporation and condensation coefficients are equal when systems are not far from equilibrium and smaller than one, and decrease with increasing temperature. For the same reduced temperature $T/T_c$, where $T_c$ is the critical temperature, these two coefficients are higher for LJ dimers and trimers than for monomers, in contrast to the traditional viewpoint that they are close to unity for monatomic molecules and decrease for polyatomic molecules. Furthermore, data for the two coefficients collapse onto a master curve when plotted against a translational length ratio between the liquid and vapor phase.Comment: revised version, 15 pages, 15 figures, to appear in J. Chem. Phy

New Approaches to HSCT Multidisciplinary Design and Optimization

The successful development of a capable and economically viable high speed civil transport (HSCT) is perhaps one of the most challenging tasks in aeronautics for the next two decades. At its heart it is fundamentally the design of a complex engineered system that has significant societal, environmental and political impacts. As such it presents a formidable challenge to all areas of aeronautics, and it is therefore a particularly appropriate subject for research in multidisciplinary design and optimization (MDO). In fact, it is starkly clear that without the availability of powerful and versatile multidisciplinary design, analysis and optimization methods, the design, construction and operation of im HSCT simply cannot be achieved. The present research project is focused on the development and evaluation of MDO methods that, while broader and more general in scope, are particularly appropriate to the HSCT design problem. The research aims to not only develop the basic methods but also to apply them to relevant examples from the NASA HSCT R&D effort. The research involves a three year effort aimed first at the HSCT MDO problem description, next the development of the problem, and finally a solution to a significant portion of the problem