Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Science, 1981. / Microfiche copy available in Archives and Science. / Vita. / Bibliography: leaves 95-96. / by Peter Reid Daifuku. / M.S.

This dissertation consists of two essays. The first provides evidence that the recent revival of shelf equity offers is related to changes in how firms use shelf registration. During 1990-2003 firms that make shelf filings have no immediate intent and low probability of issuance, lower pre-filing returns relative to non-shelf issuers, and often have been certified in prior SEOs. The evidence indicates that the way firms now use shelf offerings resolves the under-certification problem responsible for the shelf demise in the 1980s (Denis, 1991) and results in smaller market penalties and lower underwriter fees relative to non-shelf offerings. This allows firms with greater uncertainty to take advantage of the shelf option to defer or abandon offers. Additionally, firms often use universal shelf filings and choose between debt and equity offerings based on the prevailing relative market conditions. The second essay examines offer price discounting of traditional and shelf-registered seasoned equity offerings (SEOs). The results indicate that relative to traditional SEOs, shelf discounting during 1982 - June 2004 is similar in magnitude, is influenced by the same factors, and has increased similarly over time. Prior studies attribute the time-series increase of seasoned offer discounting to pre-offer short sale constraints (Rule 10b-21; adopted in 1988). This study provides insights about the effect of Rule 10b-21 by exploiting the fact that shelf-registered offerings were exempt from this regulation until September 2004. The analysis uses the shelf exemption as a control in testing the Rule's effect, and the elimination of the exemption as an "out-of-sample" test. The results suggest that Rule 10b-21 is not associated with the increase in seasoned offer discounts. The gradual increase in discounting over the past two decades is largely due to a shift in the composition of issuers toward firms that have greater stock volatility and pre-offer price uncertainty. / Ph. D.

The use of Pulsed Energy (Flashbasttm) Technology (PET) to extend the shelf life of fresh fish fillets was studied. Unskinned fillets from fresh sea trout (Cynoscion regalis) and hybrid striped bass (Morone chrysops x ~ saxatilis) were treated with 7.45 Joules/cm² of PET, stored individually in sterile polyethylene bags, and kept in ice for 21 days at 3°C. Sensory data showed no significant differences (pâ ¤ 0.05) in the appearance, odor, texture, or taste of cooked samples from treated and control fillets, regardless of species. Raw sea trout fillets developed "alien" odors upon treatment which disappeared within the first week of storage and were not detected in cooked samples. These off-odors were significant (pâ ¤ 0.05) in the freshwater species only during the first three days post-treatment. Microbiological analyses revealed that PET reduced bacteria growing on the flesh surface and skin at significantly higher (pâ ¤ 0.05) rates than those in the flesh. Total coliforms were the most susceptible bacteria to PET. / Ph. D.

Tesis por compendio / This PhD dissertation focuses on the development of renewable and biodegradable active films based on chemically-modified wheat gliadin proteins endowed with antimicrobial capacity owing to the incorporation of naturally-occurring bioactive compounds, namely cinnamaldehyde, natamycin, and lysozyme. Gliadin proteins were treated with cinnamaldehyde at acidic pH and films were produced by casting. The resulting protein-based films presented improved functional properties (mechanical, barrier, and water resistance), and biochemical evidence of the formation of a more compact network whose degree of cross-linking increased with the amount of cinnamaldehyde incorporated into the gliadin-ethanolic solution. Free cinnamaldehyde not participating in the cross-linked reaction remained entrapped in the protein matrix at low relative humidity conditions. The sensitivity of the films to moisture owing to the hydrophilic character of gliadins provided a trigger and control mechanism for the release of cinnamaldehyde in moderate and high relative humidity environments, similar to conditions occurring in packaged food products. The antimicrobial properties of the films developed were tested in vitro by vapor diffusion assays against common food spoilage fungi (Penicillium expansum and Aspergillus niger), showing great effectiveness. Application of these active films to the preservation of two foodstuffs, sliced bread and cheese spread, gave promising results, lengthening fungal growth lag phase and minimizing fungal growth extension. / Balaguer Grimaldo, MDLP. (2015). Development of active bioplastics based on wheat proteins and natural antimicrobials for food packaging applications [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/48520 / Premios Extraordinarios de tesis doctorales / Compendio

An enzyme-linked immunosorbent assay (ELISA) using polyclonal antibodies has been developed for the detection of the fluorescing group of Pseudomonas. The assay was used as a rapid test (6h) for predicting the shelf-life of pasteurized fluid milk. Milk samples were held at 7°C and tested weekly until determined to be unacceptable by daily sensory evaluation. Sterile milk samples were inoculated with target concentrations of 0 (control), 100, and 1000 cells/ml of Pseudomonas fluorescens on day 0. Samples were tested before and after preliminary incubations. Preliminary incubations conducted include milk alone and milk with broth (1:1) for 18h at 21°C. ELISA and plate counts were performed before and after preliminary incubation to determine the number of pseudomonads present and the relationship between ELISA and plate counts. These numbers were correlated to the shelf-life of each sample, as determined by sensory evaluation. Samples undergoing a preliminary incubation with only milk gave the best correlation to shelf-life (R=0.86). / Master of Science

The effects of packaging treatments, post harvest cooling delay and storage duration on color, texture, ascorbic acid content, weight loss and glucosinolate retention in crown-cut heads of broccoli were studied. Oxygen and CO2 levels inside shrink wrap packages were also monitored. Shrink wrap packaging had a significant positive effect on hue angle (p<0.05). Packaging and post harvest cooling delay had no effect on hue difference and total color difference. While post harvest cooling delay had no effect on texture, crown-cut heads of broccoli stored in shrink wrap packaging retained firmness significantly better than ice packaged heads of broccoli (p<0.05). Ascorbic acid was retained better in broccoli held in shrink wrap packages and cooling delay had a significant negative influence on ascorbic acid content (p<0.05). Packaging and post harvest cooling delay had a significant positive effect on weight loss (p<0.05). Broccoli stored in shrink wrap film lost about 3.7% of original weight while ice packaging resulted in about 17.4% weight loss (p<0.05). No consistent trends were observed in the levels of O2 and CO2 inside shrink wrap packages. An important glucosinolate, glucoraphanin was retained significantly better in shrink wrapped heads (p<0.05). Between two cultivars, shelf life of cv.Gypsy was better than cv.Everest with respect to color, ascorbic acid retention and weight loss. But cv.Everest retained texture (firmness) better after 35 days of storage. Overall results indicate that shrink wrap packaging and shorter post harvest cooling delays protect quality of broccoli. / Master of Science

Traditional plating methods for bacterial enumeration can be limited, but the development of high-throughput DNA sequencing, such as Oxford Nanopore Technologies (ONT), can provide rapid and highly specific alternative for species-level identification. In this study, ONT amplicon sequencing was applied to fresh broiler breast meat to identify their bacterial composition and monitor their dynamic changes. The sequencing data were complemented by sensory panels, physicochemical analysis, and traditional plating methods. Over time, the bacterial diversity decreased within and across samples. By the end of shelf-life, Pseudomonas fragi, Pseudomonas lundesis, and Brochothrix thermosphacta became the most prevalent species. These bacteria were associated with spoilage attributes that were reported in the sensory panels. This study demonstrated the effectiveness of Nanopore sequencing in determining the spoilage associated bacteria in chicken meat. Future research may focus on developing targeted interventions to mitigate the impact of these spoilage bacteria and extend the shelf life of chicken meat.

Cores, quarry exposures, and exploratory wells in the Paleogene Albemarle Basin, North Carolina sample the transition between the southern carbonate and northern siliciclastic provinces of the eastern U.S. continental shelf succession. The study area includes the relatively positive Cape Fear Arch on the Onslow Block to the south, and the slowly subsiding (1.5 cm/ky) Albemarle Block to the north. The Paleogene supersequence set boundary is a hardground on Cretaceous shoreface/shallow-shelf mollusk facies. It is overlain by a thin Paleocene sequence of deeper offshore, glauconitic fine sands to deep marine silt-shale. Five regionally mappable, vertically stacked Eocene sequences are 0 to 30 m thick and contain coastal sands, shoreface sandy-mollusk rudstones, offshore bryozoan grainstone-packstones and subwave base fine wackestone-packstone and marl. The Eocene sequences commonly are bounded by hardgrounds, overlain by thin local lowstand sands and consist of a thin transgressive unit (commonly absent), overlain by an upward shallowing highstand marine succession. On the arch, lowstand and transgressive units may be condensed into lags. The Lower Oligocene succession on the arch has a single marl to fine foram sand dominated sequence whereas downdip, two to three sequences are developed, capped by nearshore sandy molluscan facies. The Upper Oligocene is dominated by possibly three sequences composed of basal, thin sands up into variably sandy mollusk rudstone. Sequence development was influenced by differential movement of the basement blocks, coupled with increasing 3rd order eustatic sea level changes during global cooling. This was coupled with swell-wave and current sweeping of the shelf that effectively decreased available accommodation by 20 to 30 m, and generated the distinctive hardgrounds on sequence boundaries, and variable development of lowstand and transgressive system tracts. The well developed highstands reflect maximum accommodation allowing deposition of an upward shallowing succession that terminated at the depth of wave abrasion on the open shelf. The sequence stratigraphic development contrasts markedly with that from tropical shelves. / Master of Science

Coastal water quality is intricately linked to environmental factors, particularly meteorological and hydrological conditions. Weather conditions determine wind speed and direction, which in turn influence coastal currents, and these currents play a critical role in the transport and variability of water quality parameters. Understanding how these dynamic interactions impact water quality is essential for the effective management and preservation of coastal ecosystems. This dissertation investigates the effects of varying flow conditions on key water quality parameters in the Louisiana Continental Shelf, utilizing data from two research cruises. The study specifically focuses on how concentration variability and transport mechanisms of water quality indicators respond to different environmental conditions, including the passage of cold fronts and periods of non-frontal conditions. In this research, data were collected using a conductivity-temperature-depth (CTD) system and through the analysis of water samples to assess changes in nutrient concentrations, dissolved oxygen levels, chlorophyll-a, and Colored Dissolved Organic Matter (CDOM). These samples were collected under two distinct environmental conditions: following a cold front and during non-frontal conditions. Analytical methods were used to quantify the water quality parameters, while hydrodynamic modeling was applied to assess the transport and dispersion patterns of these indicators. The results show that cold fronts increase nutrient concentrations and decrease dissolved oxygen levels due to enhanced mixing and upwelling. The cold front activity also promotes southwestward transport of water quality parameters, driven by the region's hydrodynamic forces. Under stable weather conditions, nutrient and chlorophyll-a concentrations increase, but transport is limited, with reduced dispersion resulting from weaker hydrodynamic forces. CDOM component analysis revealed that cold front conditions lower CDOM concentrations and improve light penetration, while non-frontal conditions elevate CDOM concentrations, reducing light penetration and impacting aquatic ecosystem productivity. These findings enhance our understanding of how meteorological events, hydrological conditions, and water quality interact in coastal regions. The research demonstrates how weather conditions distinctly influence nutrient dynamics and CDOM behavior. These insights are crucial for developing effective water quality management strategies for the Louisiana Continental Shelf and similar coastal regions worldwide, supporting global efforts to mitigate challenges posed by climate change and human activity in coastal ecosystems.

Sweet potatoes are a worldwide staple crop and granola bars are popular with consumers. This study aims to create a granola bar utilizing sweet potatoes and to assess its changes over time. Initial formulations tested minimum and maximum concentration of sweet potato (SP) puree, formulations, cooking type and time/temperature, humectants and preservatives. Bars containing 30 and 45% SP butter were chosen. Changes over time and descriptive sensory evaluation were conducted every 14d for 70d, with four treatments: a control bar and a bar with a preservative, each held at 25°C and 47°C. Water activity and moisture decreased by 0.05 and 2% while microbial counts decreased and some textural attributes changed slightly after 70d. The bars contained about 140 Kcal, 2g protein and 3g fat, and over 1500ug vitamin A. Sensory panelists preferred the 45% bar, regardless of preservative. Water activity seems to be the limiting factor in shelf-life.