Mercury Levels in Marine and Estuarine Fishes of Florida 1989–2001. 2nd edition revised

The Florida Fish and Wildlife Conservation Commission’s Florida Marine Research Institute (FWC-FMRI) has examined total mercury levels in muscle tissue from a variety of economically and ecologically important species as part of an ongoing study to better understand mercury contamination in marine fishes.The FWC-FMRI Mercury Program is one of the most comprehensive programs in the United States for monitoring mercury levels in marine and estuarine fishes. Because mercury, a toxic metallic element, has been shown to bioaccumulate in fish tissue, humans consuming fish can potentially consume significant levels of mercury.We examined the concentration of total mercury in 6,806 fish, representing 108 species from 40 families. Species represented all major trophic groups, from primary consumers to apex predators.The majority of individuals we examined contained low concentrations of mercury, but concentrations in individual fish varied greatly within and among species. Species with very low mean or median mercury concentrations tended to be planktivores, detritivores, species that feed on invertebrates, or species that feed on invertebrates and small fish prey.Apex predators typically had the highest mercury concentrations. In most species, mercury concentration increased as fish size increased. Sampling in Florida waters is continuing, and future research relating mercury levels to fish age, feeding ecology, and the trophic structure of Florida’s marine and estuarine ecosystems will help us better understand concentrations of this element in marine fishes. (64pp.

Spacecraft Requirements Development and Tailoring

Spacecraft design is managed through the use of design requirements. Requirements are flowed from the highest level, the overall spacecraft, to systems, subsystems and ultimately individual components. Through the use of requirements, each part of the spacecraft will perform the functions that are required of it and will interface to the rest of the spacecraft. Functional requirements are used to make sure every component performs as expected and interface requirements ensure that each component works within the larger design environment where it operates. Writing good requirements is difficult and the verification of requirements can be expensive and time consuming. Because of this difficulty and expense, it is important that each requirement truly be required and critical to the overall performance of the vehicle. It is also important that requirements can be changed or eliminated as the system matures to minimize verification cost and schedule. The Capsule Parachute Assembly System (CPAS) Project is developing the parachute system for the NASA Multi-Purpose Crew Vehicle (MPCV) Orion Spacecraft. Throughout the development and qualification cycle for CPAS, requirements have been evaluated, added, eliminated, or more generically, tailored, to ensure that the system performs as required while minimizing the verification cost to the Program. One facet of this tailoring has been to delete requirements that do not add value to the overall spacecraft or are not needed. A second approach to minimize the cost of requirement verification has been to evaluate requirements based on the actual design as it has matured. As the design of the parachute system has become better understood, requirements that are not applicable have been eliminated. This paper will outline the evolution of CPAS requirements over time and will show how careful and considered changes to requirements can benefit the technical solution for the overall system design while allowing a Project to control costs

Geospatial modeling approach to monument construction using Michigan from A.D. 1000–1600 as a case study

Building monuments was one way that past societies reconfigured their landscapes in response to shifting social and ecological factors. Understanding the connections between those factors and monument construction is critical, especially when multiple types of monuments were constructed across the same landscape. Geospatial technologies enable past cultural activities and environmental variables to be examined together at large scales. Many geospatial modeling approaches, however, are not designed for presence-only (occurrence) data, which can be limiting given that many archaeological site records are presence only. We use maximum entropy modeling (MaxEnt), which works with presence-only data, to predict the distribution of monuments across large landscapes, and we analyze MaxEnt output to quantify the contributions of spatioenvironmental variables to predicted distributions. We apply our approach to co-occurring Late Precontact (ca. A.D. 1000–1600) monuments in Michigan: (i) mounds and (ii) earthwork enclosures. Many of these features have been destroyed by modern development, and therefore, we conducted archival research to develop our monument occurrence database. We modeled each monument type separately using the same input variables. Analyzing variable contribution to MaxEnt output, we show that mound and enclosure landscape suitability was driven by contrasting variables. Proximity to inland lakes was key to mound placement, and proximity to rivers was key to sacred enclosures. This juxtaposition suggests that mounds met local needs for resource procurement success, whereas enclosures filled broader regional needs for intergroup exchange and shared ritual. Our study shows how MaxEnt can be used to develop sophisticated models of past cultural processes, including monument building, with imperfect, limited, presence-only data

A Comparison of Student Achievement, As Measured by Marks Received, in Residence and Extension Courses at The University of New Mexico

Differences in opinion [arise] regarding the comparative quality of academic performance of students enrolled in residence and those in extension. However, no objective study has yet been made at the University of New Mexico comparing the academic performances of students in extension with that made by resident students, hence those differences of opinion have not been reconciled. In order to shed some light on the issue, this problem has been undertaken. The purpose of this study is to compare the academic achievement as measured by grade-point averages of (1) students in residence with their achievement in correspondence courses; (2) students in residence with their achievement in extension classes; (3) students in extension classes with their achievement as measured by grade-point averages of the same students in all three conditions of enrollment, namely, residence, extension classes, and correspondence courses

Palm phytoliths of mid-elevation Andean forests

Palms are one of the most common tropical plant groups. They are widespread across lowland tropical forests, but many are found in higher altitudes have more constrained environmental ranges. The limited range of these species makes them particularly useful in paleoecological and paleoclimate reconstructions. Palms produce phytoliths, or silica structures, which are found in their vegetative parts (e.g., wood, leaves, etc.). Recent research has shown that several palms in the lowland tropical forests produce phytoliths that are diagnostic to the sub-family or genus-level. Here we characterize Andean palm phytoliths, and determine whether many of these species can also be identified by their silica structures. All of our sampled Andean palm species produced phytoliths, and we were able to characterize several previously unclassified morphotypes. Some species contained unique phytoliths that did not occur in other species, particularly Ceroxylon alpinium, which is indicative of specific climatic conditions. The differences in the morphologies of the Andean species indicate that palm phytolith analysis is particularly useful in paleoecological reconstructions. Future phytolith analyses will allow researchers to track how these palm species with limited environmental ranges have migrated up and down the Andean slopes as a result of past climatic change. The phytolith analyses can track local-scale vegetation dynamics, whereas pollen, which is commonly used in paleoecological reconstructions, reflects regional-scale vegetation change

Computer-guided concentration-controlled trials in autoimmune disorders

A randomized concentration-controlled clinical trial (RCCCT) is an alternate experimental design to the standard dose-controlled study. In a RCCCT, patients are randomly assigned to predefined plasma or blood drug concentration ranges (low, medium, and high). With the caveat that concentration ranges are sufficiently separated, this design should enhance the ability to discover important concentration response relationships. FK-506, a potent and promising immunosuppressive agent for prevention and treatment of graft rejection, has shown significant clinical activity in some immune-mediated disorders. To implement the RCCCT design, a novel FK-506 intelligent dosing system (IDS) was used to guide all doses to prospectively achieve the target concentration range specified in the study protocol. Patients enrolled in these trials suffered from a variety of autoimmune disorders, including multiple sclerosis, primary biliary cirrhosis, psoriasis, autoimmune chronic active hepatitis, and nephrotic syndrome. We observed excellent predictive performance of the IDS for all patients. The accuracy (mean prediction error) of the IDS was −0.022 ng/ml and the precision (standard deviation of the prediction error) was 0.119 ng/ml. Thus, the IDS is both accurate and reproducible for autoimmune patients. We conclude that the RCCCT design, guided by an accurate and precise IDS, is an informative and cost-effective approach for evaluation of efficacy and safety of effective but highly toxic agents. © 1993 Raven Press, Ltd., New York

The Relative Abundance and Feeding Habits of Juvenile Kingfish (Sciaenidae: Menticirrhus) in a Gulf of Mexico Surf Zone

We describe seasonal and diel occurrence patterns, density, dietary progressions, and trophic relationships of Menticirrhus littoralis, M. americanus and M. saxatitis collected from the Horn Island, Mississippi, surf zone. Menticirrhus littoralis was the most abundant species (62.7%), followed by M. americanus (21.8%) and M. saxatitis (15.5%). Densities were highest during spring and summer and decreased markedly during the winter. Species showed diel changes in abundance, with abundance increasing during dusk and dawn for M. littoralis, and during the day for M. americanus and M. saxatilis. All three species showed ontogenetic progressions in diet, with siphon tips from Donax spp., cumaceans and mysids being most important to smaller (\u3c80 mm SL) M. littoralis and M. americanus; cumaceans, mysids and amphipods were most important to smaller M. saxatitis. Larger individuals of all three species fed more on whole Donax, polychaetes, Emerita talpoida, brachyurans, and fishes. Both intra- and interspecific dietary overlap was greatest for the smaller size groups of juveniles and declined with growth. Dietary overlap between 20 mm size classes was greatest for intra- compared to interspecific comparisons