Biology and Fishery for Atlantic Thread Herring, Opisthonema oglinum, along the North Carolina Coast

Thread herrings, Opisthonema spp., are small, nearshore, pelagic clupeid fishes that form dense, surface schools in tropical to subtropical coastal waters. Ecologically, thread herrings form an important forage base for many large, predatory fishes (Finucane and Vaught, 1986). Commercially, thread herrings are targeted by artisanal to moderate-sized seine fisheries off the coasts of Ecuador and Peru (Patterson and Santos, 1992), Costa Rica (Stevenson and Carranza, 1981), Venezuela, the continental margins of the Caribbean, the Gulf of Mexico, and near the islands of Cuba, Hispaniola, Puerto Rico, Jamaica, and Trinidad (Reintjes, 1978). Most of the catch is reduced to fish meal and fish oil (Patterson and Santos, 1992), although minor quantities are used for human consumption (Reintjes, 1978)

The Bait Purse-seine Fishery for Atlantic Menhaden, Brevoortia tyrannus, in the Virginia Portion of Chesapeake Bay

Through the mid 1990’s, the bait purse-seine fishery for Atlantic menhaden, Brevoortia tyrannus, in the Virginia portion of Chesapeake Bay was essentially undocumented. Beginning in 1995, captains of Virginia bait vessels maintained deck logs of their daily fishing activities; concurrently, we sampled the bait landings for size and age composition of the catch. Herein, we summarize 15 years (1995–2009) of data from the deck logbooks, including information on total bait landings by purse seine, proportion of fishing to nonfishing days, proportion of purse-seine sets assisted by spotter pilots, nominal fishing effort, median catches, and temporal and areal trends in catch. Age and size composition of the catch are described, as well as vessel and gear characteristics and disposition of the catch

Stock assessment of the Atlantic menhaden, Brevoortia tyrannus, fishery

A stock assessment of the Atlantic menhaden, Brevoortia tyrannus, fishery was conducted with purse-seine landings data from 1940 to 1984 and port sampling data from 1955 to 1984. These data were analyzed to determine growth rates, maximum sustainable yield (MSY), spawner-recruit relationships, and yield per recruit. Virtual population analysis was used to estimate stock size, year class size, and fishing mortality rates. Surplus production models produced estimates of MSY from 450 to 490 kmt compared with yields of 416to 436 kmt based roughly on maximum recruitment from a weak spawner-recruit relationship. Recruitment to age-I ranged from 1.2 to 14.8 billion fish for year classes 1955-81. Recent mean recruitment to age-I for the 1975-81 year classes averaged 5.7 billion fish and compared favorably with the mean of 7.7 billion age-I fish recruited during the late 1950's. Mean recruitment from recent years suggests possible coastwide yields of 416 to 481 kmt. Continued dominance of late age-2 spawners among the spawning stock is of concern, since the stock is at greater risk through poor recruitment if recent favorable environmental conditions change. Yield-per-recruit estimates ranged from 46 g to 59 g since 1970. The high dependency of the modern fishery on prespawners has increased concerns about fluctuations in year-to-year availability and catches. To increase yield and enhance the stability of the resource, the number of age classes contributing significantly to the fishery should be increased, creating a butTer against future poor recruitment years and lessening the year-to-year fluctuations in landings. (PDF file contains 24 pages.

Manned Mars mission cost estimate

The potential costs of several options of a manned Mars mission are examined. A cost estimating methodology based primarily on existing Marshall Space Flight Center (MSFC) parametric cost models is summarized. These models include the MSFC Space Station Cost Model and the MSFC Launch Vehicle Cost Model as well as other modes and techniques. The ground rules and assumptions of the cost estimating methodology are discussed and cost estimates presented for six potential mission options which were studied. The estimated manned Mars mission costs are compared to the cost of the somewhat analogous Apollo Program cost after normalizing the Apollo cost to the environment and ground rules of the manned Mars missions. It is concluded that a manned Mars mission, as currently defined, could be accomplished for under $30 billion in 1985 dollars excluding launch vehicle development and mission operations

Polyimide from bis(n-isoprenyl)s of aryl diamides

A process and polyimide product formed by the reaction of a bismaleimide with a bis(amidediene) is disclosed wherein the bis(amidediene) is formed by reacting an excess of an acid chloride with 1,4-N,N'-diisoprenyl 2,3,5,6-tetramethy1 benzene

Mammalian Diversity and Distribution in Human-Altered Tropical Landscapes

Habitat loss at the hands of human enterprise continues to drive the global decline in biodiversity. While much attention has been placed on the use of protected areas as a means of conservation, there is an increasing need to understand the capacity of unprotected, human-altered landscapes to provide refugia and connectivity at larger spatial scales. This study evaluates the mammalian diversity that persists under alternative land management regimes and degrees of landscape change in south-central Sumatra, Indonesia. Species occurrence data compiled from extensive field surveys across 1600km2 form the basis for analyses of community composition and speciesspecific responses to the current landscape. Results indicate that species richness declined with increased landscape alteration. The lowest observed species numbers were in areas of industrial scale oil palm production rather than scrub habitats or degraded forest. Endangered mammals that persisted in the wider matrix were extirpated from the oil palm dominated areas. Comparisons between the ecological traits shared by persistent versus locally extirpated species revealed that in the initial stages of landscape change there is the capacity to support large specialist species with slow life histories. As landscape degradation continues to an agricultural matrix only habitat and diet generalists persisted. Tests of species-specific responses to landscape alteration focussed on the occurrence patterns of Sumatran tigers (Panthera tigris sumatrae) and four principal prey species. Measures of human prevalence derived from survey data and a novel application of occupancy estimation techniques, identified significant negative responses to higher levels of landscape development. Satellite derived measures of habitat connectivity and localised landcover degradation found that connectivity to areas of least disturbed forest was more important for reclusive species such as tapir (Tapirus indicus) and red muntjac (Muntiacus muntjak), while the occurrence of the wide-ranging tiger was more strongly influenced by local landcover degradation. The capacity of human altered landscapes to contribute to the conservation of mammalian communities is closely allied to the availability of degraded forests rather than alternative human altered landcovers. Given that these areas of forest are increasingly subject to degradation and conversion, spatial planning and proactive management are required to safeguard these resources

Structured Codes Improve the Bennett-Brassard-84 Quantum Key Rate

A central goal in information theory and cryptography is finding simple characterizations of optimal communication rates under various restrictions and security requirements. Ideally, the optimal key rate for a quantum key distribution (QKD) protocol would be given by a single-letter formula involving optimization over a single use of an effective channel. We explore the possibility of such a formula for the simplest and most widely used QKD protocol, Bennnett-Brassard-84 with one-way classical postprocessing. We show that a conjectured single-letter formula is false, uncovering a deep ignorance about good private codes and exposing unfortunate complications in the theory of QKD. These complications are not without benefit—with added complexity comes better key rates than previously thought possible. The threshold for secure key generation improves from a bit error rate of 0.124 to 0.129

Droplet evaporation losses during sprinkler irrigation: an overview

A detailed understanding regarding the evaporation losses in sprinkler irrigation is important for developing as well as adopting appropriate water conservation strategies. To explain this phenomenon many theoretical and experimental studies have been conducted since the 1950‟s. Notwithstanding all these efforts, the contribution of droplet evaporation to the total evaporation losses during sprinkler irrigation is still a controversial issue in the irrigation community. There is a substantial difference among researchers regarding the magnitudes of the different components of the total evaporation in sprinkler irrigation especially droplet evaporation losses. Field studies reported that the droplet evaporation losses ranged from 2 – 45%, whereas theoretical studies indicated that it is less than 1%. This is due largely to the limitations of the traditional measurement methods. However, it is likely that these limitations can be overcome and accurate measurements obtained using the eddy covariance (ECV) technique

Radiotherapy Ergonomic Patient Positioning System

External beam radiotherapy is a powerful tool to combat cancer, but requires precise positioning of patients. The standard practice involves patients lying on treatment tables within immobilization equipment. These systems have limited clearance between treatment sources and the patient that can be uncomfortable or claustrophobic for patients. Patients may move when uncomfortable, leading to improper dose delivery, possibly causing painful side effects or further cancers. We present an alternative, open configuration patient positioning solution for more ergonomic setup options with competitive positioning capabilities compared to conventional systems. Our ergonomic positioning system consists of a seat for patients on a scissor lift for vertical positioning, a gantry system for horizontal positioning, all assembled onto a rotating base for treatment of tumors from any angle. Motion up to ±25 cm in 3D was achieved by controlling stepper motors with a Raspberry Pi computer. Computer-aided design was performed to complete finite element analysis on all load-bearing structures to ensure a maximum load of 200 lbs. The design developed allows new treatment configurations with static radiation sources while the positioning system moves at a distance, which allows greater flexibility in patient positioning. Replacing conventional treatment tables enables patients to be seated during treatment, which could improve patient comfort for more comfortable immobilization and more effective radiotherapy.https://scholarscompass.vcu.edu/capstone/1215/thumbnail.jp