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.

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

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

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

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.

A ancoragem ortodôntica tem sido motivo de preocupação para os ortodontistas desde o inicio da prática ortodôntica. Os dispositivos transitórios de ancoragem esquelética (miniparafuso) definiram um novo conceito de ancoragem em Ortodontia. A colocação dos dispositivos em uma região extra-alveolar mandibular permite o uso de parafusos de maior diâmetro que podem ser inseridos paralelamente à inclinação axial de molares inferiores sem interferir com as raízes dos dentes que serão movimentados. Na literatura são descritos diferentes tipos faciais que diferem na predominância em relação ao padrão de crescimento facial vertical ou horizontal configurando conformações ósseas mandibulares distintas entre os tipos faciais. Desta forma, o objetivo deste estudo é avaliar se há diferença na espessura do osso vestibular na região do shelf mandibular entre os tipos faciais. Para este estudo retrospectivo foi selecionada uma amostra composta por 84 tomografias computadorizadas por feixe cônico (TCFC) de indivíduos dos gêneros masculino e feminino, adultos, com idade entre 18 e 40 anos. As imagens foram avaliadas no software Dolphin® (versão 11.0, Dolphin Imaging and Management Solutions, Chatsworth, CA - EUA). As tomografias foram divididas em três grupos de acordo com o tipo facial, determinado por meio de reconstruções bidimensionais em norma lateral para realização do traçado da análise cafalométrica proposta por Bjork-Jarabak, sendo: 28 do tipo facial hiperdivergente (Grupo1), 28 do tipo facial neutro (Grupo 2) e 28 do tipo facial hipodivergente (Grupo 3). Para atender aos objetivos do estudo, as medidas foram realizadas nas seguintes regiões: 1- Vestibular da raiz mesial do primeiro molar inferior dos lados esquerdo e direito; 2 - Vestibular da raiz distal do primeiro molar inferior dos lados esquerdo e direito; 3 - Vestibular entre o primeiro e segundo molar inferior dos lados esquerdo e direito; 4 - Vestibular da raiz mesial do segundo molar inferior dos lados esquerdo e direito; 5 - Vestibular da raiz distal do segundo molar inferior dos lados esquerdo e direito. As medidas foram realizadas a 3, 6 e 9 milímetros a partir da junção amelocementária (JAC) dos primeiros e segundos molares, em direção apical, no corte axial, estendendo-se do ponto médio das raízes mesial e distal até a borda mais externa da cortical óssea alveolar adjacente. Os resultados mostraram que, com relação à idade e gênero, não houve diferença estatisticamente significativa entre os grupos. As medidas do Grupo 1 mostraram que na vestibular da raiz distal do 2º molar a 9mm da JAC apresentaram, em média, valores maiores de 5mm, sendo considerada possível de instação de miniparafuso nesta região, em ambos os lados. No grupo 2 observou-se espaço suficiente para instalação de miniparafuso na vestibular da raiz distal do 2º molar a 6 mm e 9 mm da JAC. Para o Grupo 3 observou-se medidas acima de 5 mm na vestibular da raiz mesial dos segundos molares a 9 mm da JAC e na vestibular da raiz distal a 6 mm e 9 mm da JAC. Baseados nos resultados obtidos, consideramos que existe uma diferença de espessura entre os tipos faciais e que este fator deve ser considerado durante o planejamento para instalação de miniparafusos de ancoragem ortodôntica, no entando para todos os grupos a região mais adequada é na vestibular da raiz distal dos segundos molares inferiores. / Orthodontic anchorage has been of concern to orthodontists since the beginning of orthodontic practice. The transitory anchorage devices (miniscrew) have defined a new concept of anchorage in Orthodontics. Placement of the devices in a mandibular extra alveolar region allows the use of larger diameter screws that can be inserted parallel to the axial inclination of lower molars without interfering with the roots of the teeth that will be moved. The literature describes different facial types that differ in the predominance in relation to the vertical or horizontal facial growth pattern, configuring different mandibular bone conformations between the facial types. Thus, the objective of this study is to evaluate if there is difference in the thickness of the buccal bone in the MBS region between the facial types. For this retrospective study, a sample composed of 84 Cone Beam Computed Tomography (CBCT) of males and females adults, aged between 18 and 40 years, was selected. The images were evaluated in Dolphin® software (version 11.0, Dolphin Imaging and Manegement Solutions, Chatsworth, CA - USA). CT scans were divided into three groups according to the facial type, pre-determined by two-dimensional reconstructions in lateral norm for tracing cephalometric analysis proposed for Bjork-Jarabak\'s: 28 of the hyperdivergent facial type (Group 1), 28 of the neutral facial type (Group 2) and 28 of the hypodivergent facial type (Group 3). To respond the objectives of the study, the measurements were performed in the following regions: 1- Mesial root vestibular of the first lower molar of the left and right sides; 2 - Vestibular of the distal root of the first lower molar of the left and right sides; 3 - Vestibular between the first and second lower molars of the left and right sides; 4 - Vestibular mesial root of the second lower molar of the left and right sides; 5 - Vestibular of the distal root of the second lower molar of the left and right sides. Measurements were made at 3, 6 and 9 millimeters from the amelocemental junction of the first and second molars, apically in the axial cut, extending from the midpoint of the mesial and distal roots to the external border of the alveolar cortical bone adjacent. The results showed that, regarding age and gender, there was no significant statistical difference between the groups. The measurements of Group 1 showed that in the distal root of the 2nd molar to 9mm of the JAC presented, in average, values greater than 5mm, being considered possible of insertion of miniscrew in this region, in both sides. In group 2, sufficient space was observed for the installation of a miniscrew in the distal root of the 2nd molar to 6 mm and 9 mm of the JAC. For Group 3, measurements above 5 mm in the mesial root of the 2nd molars were observed at 9 mm from the JAC and in the distal root of 2nd to 6 mm and 9 mm of the JAC. Based on the results obtained, we consider that there is a difference in thickness between the facial types and that this factor should be considered during the planning for installation of orthodontic miniscrew, whereas for all groups the most suitable region is the vestibular of the distal root of second molars.

The purpose of this project was to evaluate the antioxidant activity in vitro and its effects at the oxidative stability of mechanically deboned poultry meat (MDPM) of five natural extracts. It was studied: the yerba mate (Ilex paraguariensis), the marcela (Achyrocline satureioides), a mixture of yerba mate (50%) and marcela (50%), green tea (Camellia sinensis) and propolis without alcohol. The synthetic antioxidant BHA (Butylated Hydroxianisole) was used as a positive control and the meat treated with no antioxidant was used as negative control. Natural extracts were evaluated in vitro for quantification of phenolic and flavonols total content, for antioxidant activity, by DPPH radicalscavenging, Phosphomolybdenum complex and Reducing Power assay methods. All antioxidants were mixed separately in different and equal portions of mechanically deboned poultry meat, as follow: 0.50% of yerba mate, marcela and the mixture, 0.05% of green tea, 0.10% of própolis without alcohol and 0.02% of BHA. Samples of MDPM were packed and storage at 0 to +4ºC for 10 days. The samples were evaluated each two days and the pH, TBARS and peroxide index were measured, as well as the Total Mesophilic Aerobic counts, Total Coliforms, E. coli, Lactic Bacteria, Clostridium perfringens, Salmonella spp and Staphylococcus aureus. Surface and internal colour ( L*, a*, b*) were measured and pictures of each treatment were done. Green tea extract showed the higher (p<0.05) phenolics contents and the higher (p<0.05) antioxidant activity in vitro compared to the other extracts. Yerba mate extract showed the higher (p<0.05) flavonols content. Propolis without alcohol extract showed the lowest (p<0.05) phenolics, flavonols and antioxidant activity in vitro. Marcela had the best oxidative inhibitory effect at the MDPM, with the lowest TBARS values. Propolis extract showed the best performance for the meat colour stability. Natural antioxidant addition do not interfere at MDPM pH and peroxide values. Salmonella spp was not detected in any of the samples evaluated and the results found to Staphylococcus aureus were in agreement with the Brazilian Mechanically Deboned Meat Legislation. The mixture of extracts showed the lowest (p<0.05) media for Total Mesophilic Aerobic counts. Propolis extract showed the lowest media count for Total Coliforms, E. coli and Clostridium perfringens. Yerba mate extract showed the lowest media count for Lactic Bacteria. The use of natural antioxidants should provide benefits in relation to the MDPM lipid oxidation and the microbiological growth inhibition. More researchs are necessary, looking for a better understanding about the action mechanisms of these extracts. / Este trabalho teve como objetivo avaliar cinco extratos naturais em relação a sua atividade antioxidante in vitro e na Carne Mecanicamente Separada (CMS) de frango. Foram estudadas a erva mate (Ilex paraguariensis), a marcela (Achyrocline satureioides), uma mistura de erva mate (50%) com marcela (50%), o chá verde (Camellia sinensis) e o própolis sem álcool. O antioxidante sintético BHA foi utilizado como controle positivo e o tratamento sem adição de antioxidante como controle negativo. Nos extratos naturais foram identificados o conteúdo total de fenólicos, flavonóides e a atividade antioxidante pelos métodos do DPPH, Fosfomolibdênio e do Poder de Redução. Todos os extratos foram aplicados separadamente em porções distintas e iguais de Carne Mecanicamente Separada (CMS) de frango, sendo os percentuais de aplicação de 0,50% de erva mate, marcela e da mistura, 0,05% de chá verde, 0,10% do própolis sem álcool e 0,02% de BHA. A CMS de frango foi mantida sob refrigeração de 0 a +4ºC durante 10 dias. As amostras foram avaliadas a cada dois dias, em relação ao pH, índice de TBARS, índice de peróxido, em relação a contagem média de Aeróbios Mesófilos Totais, Coliformes Totais, E. coli, Bactérias lácticas, Clostridium perfringens, Salmonella spp e Staphylococcus aureus. A cor objetiva (L*, a*, b*) foi medida na superfície e na parte interna da CMS de frango assim como o registro em foto de cada tratamento. O extrato de chá verde apresentou o maior (p<0,05) conteúdo de fenólicos e a maior (p<0,05) atividade antioxidante in vitro em relação aos demais extratos. O extrato de erva mate apresentou o maior (p<0,05) conteúdo de flavonóides. O extrato de própolis sem álcool apresentou os menores (p<0,05) conteúdos de fenólicos, de flavonóides e a menor atividade antioxidante in vitro. O extrato de marcela teve o melhor efeito na inibição da oxidação lipídica da CMS de frango, apresentando os menores valores médios de TBARS. O extrato de própolis sem álcool manteve por mais tempo a estabilidade da cor da carne. A adição dos antioxidantes naturais não interferiu no pH e nem no índice de peróxido da CMS de frango. Não foi detectada a presença de Salmonella spp e os resultados de Staphylococcus aureus ficaram dentro dos padrões estabelecidos pela Legislação. O tratamento com a mistura de extratos de erva mate e de marcela apresentou a menor (p<0,05) contagem média de Aeróbios Mesófilos Totais em relação aos demais tratamentos. O extrato de própolis sem álcool apresentou a menor contagem média de Coliformes totais, E. coli e Clostridium perfringens. O extrato de erva mate apresentou a menor contagem média de Bactérias lácticas. O uso de antioxidantes naturais pode trazer benefícios em relação a inibição da população microbiana da CMS de frango. Mais estudos são necessários visando um melhor entendimento dos mecanismos de ação desses extratos na carne mecanicamente separada (CMS) de frango.