Effects of macrobenthos on sediment-water oxygen and ammonium fluxes. Final Report.

Sediments are an important location in determining the fate of nutrients entering the estuary. Role of sediments needs to be incorporated into water quality models. Purpose of this study was to estimate the portion of sediment oxygen consumption (SOC) and sediment ammonium (NH4+) release directly attributable to benthic invertebrates via the respiratory use of oxygen and catabolic release of ammonium. Samples were collected at 8 locations from August 1985 through November 1988. (PDF contains 45 pages

On Real-Time Synthetic Primate Vision

The primate vision system exhibits numerous capabilities. Some important basic visual competencies include: 1) a consistent representation of visual space across eye movements; 2) egocentric spatial perception; 3) coordinated stereo fixation upon and pursuit of dynamic objects; and 4) attentional gaze deployment. We present a synthetic vision system that incorporates these competencies.We hypothesize that similarities between the underlying synthetic system model and that of the primate vision system elicit accordingly similar gaze behaviors. Psychophysical trials were conducted to record human gaze behavior when free-viewing a reproducible, dynamic, 3D scene. Identical trials were conducted with the synthetic system. A statistical comparison of synthetic and human gaze behavior has shown that the two are remarkably similar

Enabling flexibility through strategic management of complex engineering systems

”Flexibility is a highly desired attribute of many systems operating in changing or uncertain conditions. It is a common theme in complex systems to identify where flexibility is generated within a system and how to model the processes needed to maintain and sustain flexibility. The key research question that is addressed is: how do we create a new definition of workforce flexibility within a human-technology-artificial intelligence environment? Workforce flexibility is the management of organizational labor capacities and capabilities in operational environments using a broad and diffuse set of tools and approaches to mitigate system imbalances caused by uncertainties or changes. We establish a baseline reference for managers to use in choosing flexibility methods for specific applications and we determine the scope and effectiveness of these traditional flexibility methods. The unique contributions of this research are: a) a new definition of workforce flexibility for a human-technology work environment versus traditional definitions; b) using a system of systems (SoS) approach to create and sustain that flexibility; and c) applying a coordinating strategy for optimal workforce flexibility within the human- technology framework. This dissertation research fills the gap of how we can model flexibility using SoS engineering to show where flexibility emerges and what strategies a manager can use to manage flexibility within this technology construct”--Abstract, page iii

Prevention of infection and disruption of the pathogen transfer chain in elective surgery

The COVID-19 pandemic has caused us all to stop our normal activities and consider how we can safely return to caring for our patients. There are many common practices (such as an increased use of personal protective equipment) which we are all familiar with that can be easily incorporated into our daily routines. Other actions, such as cleaning more surfaces with solutions such as dilute povidone iodine or changing the air filtration systems used within operating room theaters, may require more extensive efforts on our behalf. In this article, we have attempted to highlight some of the changes that arthroplasty surgeons may need to instigate when we are able to resume elective joint arthroplasty procedures in an effort to disrupt the chain of pathogen transfer

Time-Series Photometry of Stars in and around the Lagoon Nebula. I. Rotation Periods of 290 Low-Mass Pre-Main-Sequence Stars in NGC 6530

We have conducted a long-term, wide-field, high-cadence photometric monitoring survey of ~50,000 stars in the Lagoon Nebula \ion{H}{2} region. This first paper presents rotation periods for 290 low-mass stars in NGC 6530, the young cluster illuminating the nebula, and for which we assemble a catalog of infrared and spectroscopic disk indicators, estimated masses and ages, and X-ray luminosities. The distribution of rotation periods we measure is broadly uniform for 0.5 < P < 10 d; the short-period cutoff corresponds to breakup. We observe no obvious bimodality in the period distribution, but we do find that stars with disk signatures rotate more slowly on average. The stars' X-ray luminosities are roughly flat with rotation period, at the saturation level ($\log L_X / L_{\rm bol} \approx -3.3$). However, we find a significant positive correlation between $L_X / L_{\rm bol}$ and co-rotation radius, suggesting that the observed X-ray luminosities are regulated by centrifugal stripping of the stellar coronae. The period-mass relationship in NGC 6530 is broadly similar to that of the Orion Nebula Cluster (ONC), but the slope of the relationship among the slowest rotators differs from that in the ONC and other young clusters. We show that the slope of the period-mass relationship for the slowest rotators can be used as a proxy for the age of a young cluster, and we argue that NGC 6530 may be slightly younger than the ONC, making it a particularly important touchstone for models of angular momentum evolution in young, low-mass stars.Comment: 28 pages, 18 figures, Accepted for publication in ApJ. For a brief video explaining the key results of this paper, see http://www.youtube.com/user/OSUAstronomy#p/u/1/WarGh6GiWu

Enabling Flexibility through Forming and Evolving Systems of Systems

Flexibility is a highly desired attribute of many systems operating in changing or uncertain conditions. This paper presents a study of enabling flexibility through designing and operating systems of systems (SoSs). The paper analyzes flexibility mechanisms of SoSs and, accordingly, identifies needs for flexibility that SoSs can meet. Following that, it proposes a hierarchical network as a more flexible SoS architecture for complex or distributed large-scale systems. Then, decision problems for forming and evolving a SoS network are defined. A case that involves integrating distributed renewable energy sources with the main grid is presented to illustrate the implementation of the proposed methodology. Results from this study support the idea of acquiring and maintaining flexibility with SoSs. The paper also identifies research needs for advancing this particular use of SoSs

The secondary star and distance of the polar V1309 Ori

The first phase-resolved JHK light curves of the eclipsing polar (AM Herculis binary) V1309 Ori are presented and interpreted. We separate the contributions from the secondary star and from other sources with the aim of determining a photometric distance. Simple model calculations show that the accretion stream and the cyclotron source on the accreting white dwarf are minor contributors to the infrared light, allowing an accurate determination of spectral type and absolute flux of the secondary star. The unilluminated backside of the secondary star as seen in eclipse has spectral type dM0 to dM0+. Its dereddened magnitude is K = 13.58 at orbital phase phi = 0 (eclipse). Using the calibrated surface brightness of M-stars and the published mass of the secondary, M2 = 0.46 Msun, we obtain a distance d = 600 +/- 25 pc which scales as M2^(1/2). The radius of the Roche-lobe filling secondary exceeds the main-sequence radius of an M0 star by 21 +11/-6 %. The debated origin of the infrared light of V1309 Ori has been settled in favor of the secondary star as the main contributor and an accurate distance has been derived that will place estimates of the luminosity and synchronization time scale on a more secure basis.Comment: 5 pages, 3 figures, accepted for publication in Astronomy and Astrophysic

Evolution in the black hole mass-bulge mass relation: a theoretical perspective

We explore the growth of super-massive black holes and host galaxy bulges in the galaxy population using the Millennium Run LCDM simulation coupled with a model of galaxy formation. We find that, if galaxy mergers are the primary drivers for both bulge and black hole growth, then in the simplest picture one should expect the mBH-mbulge relation to evolve with redshift, with a larger black hole mass associated with a given bulge mass at earlier times relative to the present day. This result is independent of an evolving cold gas fraction in the galaxy population. The evolution arises from the disruption of galactic disks during mergers that make a larger fractional mass contribution to bulges at low redshift than at earlier epochs. There is no comparable growth mode for the black hole population. Thus, this effect produces evolution in the mBH-mbulge relation that is driven by bulge mass growth and not by black holes.Comment: 6 pages, 3 figures, minor revisions, replaced with accepted MNRAS versio