9 research outputs found

    ANALYSIS OF THE POPULATION DYNAMICS OF PLACIDA DENDRITICA AND CODIUM FRAGILE IN THE GULF OF MAINE AND A THEORETICAL DISCUSSION OF INVASIVE SPECIES

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    This dissertation examines several aspects of the biology and ecology of Codium fragile and Placida dendritica in the Gulf of Maine. Scientific interest in nonindigenous species was examined to determine if any patterns were evident that might indicate a change in the status of an invasive species. Interest in C. fragile had waned in recent years, the timing of which coincides with the decreased ecological dominance and apparent naturalization of the alga. Laboratory and field studies were combined to quantify the dynamics in the population of C. fragile and in the recruitment dynamics of P. dendritica. Results of laboratory research indicate a strong influence of temperature on the biology and physiology of P. dendritica; however, field research indicates that abundance of C. fragile may be a more significant driver of the recruitment of the sea slug than temperature. A mathematical model was reconciled the effects of temperature and algal abundance on larval recruitment to determine if recruitment P. dendritica can be accurately predicted from the two measurements. Calibration and testing of the model indicated that temperature was largely responsible for the individual reproductive output and duration of larval development, while the abundance of C. fragile likely has a greater influence on the timing of maximum recruitment each year

    Field and laboratory observations of two Gulf of Maine sacoglossans

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    The ecology of the sacoglossan Alderia modesta and its ability to retain active chloroplasts from the yellow-green alga Vaucheria spp. was examined with field and laboratory studies. Field surveys found no A. modesta, because Vaucheria spp. was absent or sparse in surveyed marshes. A grass removal experiment tested whether interspecific competition was causing the algal absence. The alga appeared in some plots, but did not promote A. modesta settlement. Absence of Vaucheria spp. is likely due to factors other than competition. Lack of animals prevented laboratory studies. Placida dendritica and its food Codium fragile ssp. fragile were then chosen for ecology and photosynthesis studies. Field surveys indicated year-round presence, greatest abundance in summer, and preferential larval settlement on larger C. fragile thalli. Photosynthetic potential was evaluated through oxygen consumption, growth, and phototaxis experiments. Oxygen consumption and growth showed inactive chloroplasts from C. fragile, but behavior indicated the possibility for active chloroplasts from other algal species

    Report on the 2013 Rapid Assessment Survey of Marine Species at New England Bays and Harbors

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    Introduced species (i.e., non-native species that have become established in a new location) have increasingly been recognized as a concern as they have become more prevalent in marine and terrestrial environments (Mooney and Cleland 2001; Simberloff et al. 2005). The ability of introduced species to alter population, community, and ecosystem structure and function, as well as cause significant economic damage is well documented (Carlton 1989, 1996b, 2000; Cohen and Carlton 1995; Cohen et al. 1995; Elton 1958; Meinesz et al. 1993; Occhipinti-Ambrogi and Sheppard 2007; Pimentel et al. 2005; Thresher 2000). The annual economic costs incurred from managing the approximately 50,000 introduced species in the United States alone are estimated to be over $120 billion (Pimentel et al. 2005). Having a monitoring network in place to track new introductions and distributional changes of introduced species is critical for effective management, as these efforts may be more successful when species are detected before they have the chance to become established. A rapid assessment survey is one such method for early detection of introduced species. With rapid assessment surveys, a team of taxonomic experts record and monitor marine species–providing a baseline inventory of native, introduced, and cryptogenic (i.e., unknown origin) species (as defined by Carlton 1996a)–and document range expansions of previously identified species. Since 2000, five rapid assessment surveys have been conducted in New England. These surveys focus on recording species at marinas, which often are in close proximity to transportation vectors (i.e., recreational boats). Species are collected from floating docks and piers because these structures are accessible regardless of the tidal cycle. Another reason for sampling floating docks and other floating structures is that marine introduced species are often found to be more prevalent on artificial surfaces than natural surfaces (Glasby and Connell 2001; Paulay et al. 2002). The primary objectives of these surveys are to: (1) identify native, introduced, and cryptogenic marine species, (2) expand on data collected in past surveys, (3) assess the introduction status and range extensions of documented introduced species, and (4) detect new introductions. This report presents the introduced, cryptogenic, and native species recorded during the 2013 survey

    Rationale, design, and methodology for the optimizing outcomes in women with gestational diabetes mellitus and their infants study

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    Background Women who are diagnosed with gestational diabetes mellitus (GDM) are at increased risk for developing prediabetes and type 2 diabetes mellitus (T2DM). To date, there have been few interdisciplinary interventions that target predominantly ethnic minority low-income women diagnosed with GDM. This paper describes the rationale, design and methodology of a 2-year, randomized, controlled study being conducted in North Carolina. Methods/Design Using a two-group, repeated measures, experimental design, we will test a 14- week intensive intervention on the benefits of breastfeeding, understanding gestational diabetes and risk of progression to prediabetes and T2DM, nutrition and exercise education, coping skills training, physical activity (Phase I), educational and motivational text messaging and 3 months of continued monthly contact (Phase II). A total of 100 African American, non-Hispanic white, and bilingual Hispanic women between 22–36 weeks of pregnancy who are diagnosed with GDM and their infants will be randomized to either the experimental group or the wait-listed control group. The first aim of the study is to determine the feasibility of the intervention. The second aim of study is to test the effects of the intervention on maternal outcomes from baseline (22–36 weeks pregnant) to 10 months postpartum. Primary maternal outcomes will include fasting blood glucose and weight (BMI) from baseline to 10 months postpartum. Secondary maternal outcomes will include clinical, adiposity, health behaviors and self-efficacy outcomes from baseline to 10 months postpartum. The third aim of the study is to quantify the effects of the intervention on infant feeding and growth. Infant outcomes will include weight status and breastfeeding from birth through 10 months of age. Data analysis will include general linear mixed-effects models. Safety endpoints include adverse event reporting. Discussion Findings from this trial may lead to an effective intervention to assist women diagnosed with GDM to improve maternal glucose homeostasis and weight as well as stabilize infant growth trajectory, reducing the burden of metabolic disease across two generations. Trial registration NCT0180943

    Report on the 2013: Rapid assessment survey of marine species at New England Bays and Harbors

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    Introduced species (i.e., non-native species that have become established in\ud a new location) have increasingly been recognized as a concern as they have\ud become more prevalent in marine and terrestrial environments (Mooney and\ud Cleland 2001; Simberloff et al. 2005). The ability of introduced species to alter\ud population, community, and ecosystem structure and function, as well as\ud cause significant economic damage is well documented (Carlton 1989, 1996b,\ud 2000; Cohen and Carlton 1995; Cohen et al. 1995; Elton 1958; Meinesz et al.\ud 1993; Occhipinti-Ambrogi and Sheppard 2007; Pimentel et al. 2005; Thresher\ud 2000). The annual economic costs incurred from managing the approximately\ud 50,000 introduced species in the United States alone are estimated to be over\ud $120 billion (Pimentel et al. 2005).\ud Having a monitoring network in place to track new introductions and\ud distributional changes of introduced species is critical for effective\ud management, as these efforts may be more successful when species are\ud detected before they have the chance to become established. A rapid\ud assessment survey is one such method for early detection of introduced\ud species. With rapid assessment surveys, a team of taxonomic experts\ud record and monitor marine species–providing a baseline inventory of\ud native, introduced, and cryptogenic (i.e., unknown origin) species (as\ud defined by Carlton 1996a)–and document range expansions of previously\ud identified species.\ud Since 2000, five rapid assessment surveys have been conducted in New\ud England. These surveys focus on recording species at marinas, which often\ud are in close proximity to transportation vectors (i.e., recreational boats).\ud Species are collected from floating docks and piers because these structures\ud are accessible regardless of the tidal cycle. Another reason for sampling floating\ud docks and other floating structures is that marine introduced species are often\ud found to be more prevalent on artificial surfaces than natural surfaces (Glasby\ud and Connell 2001; Paulay et al. 2002). The primary objectives of these surveys\ud are to: (1) identify native, introduced, and cryptogenic marine species,\ud (2) expand on data collected in past surveys, (3) assess the introduction status\ud and range extensions of documented introduced species, and (4) detect new\ud introductions. This report presents the introduced, cryptogenic, and native\ud species recorded during the 2013 survey.CZM through NOAA NA13NOS4190040MIT Sea Grant through NOAA NA10OAR4170086

    Connector development for hybrid masonry seismic structural systems

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    M.S. University of Hawaii at Manoa 2011.Includes bibliographical references.Hybrid masonry construction has relatively recently been developed as a means to provide a more efficient use of masonry infill walls by designing these walls to function as a part of a structure's lateral force resisting system, with current applications in low seismic regions (Seismic Design Categories A, B, and C). In regions of higher seismicity (Seismic Design Categories D and greater), there exists a much greater need for a clearer understanding of the mechanics of the interaction between the steel frame of a building and the masonry shear wall as well as the development of specific detailing requirements to provide for a ductile and somewhat predictable response in a seismic event of significant magnitude. The scope of this thesis is the investigation of the connection between the steel beam and the top of the masonry wall for a Type I hybrid masonry system, using a proposed steel connector plate through-bolted to the masonry wall bond beam, in order to provide preliminary guidelines and recommendations for the development of energy dissipating hybrid masonry connector plates. The first portion of this study focused on the development of connector plate designs to determine which provided the most stable, ductile cyclic response. The second portion of this study investigated the strength and limit states of the through-bolted connection to the masonry wall bond beam under shear loading. Based on these experiments, recommendations are provided for the most suitable connector plate designs as well as a general evaluation of the connection to the masonry wall and potential limit states to consider in future design applications. For a "rigid" connection between the steel frame and CMU wall, link connectors with a thickness greater than 0.5 inches is recommended, whereas fuse Type T was proven to be superior for a ductile, energy dissipating connector plate. ACI 530-08 design values for bolt shear yielding and masonry shear failure were determined to be the most appropriate limit states for determining an approximate design values for the thru-bolted CMU wall connections

    Getting the Hologenome Concept Right: an Eco-Evolutionary Framework for Hosts and Their Microbiomes

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    International audienceGiven the complexity of host-microbiota symbioses, scientists and philosophers are asking questions at new biological levels of hierarchical organization-what is a holobiont and hologenome? When should this vocabulary be applied? Are these concepts a null hypothesis for host-microbe systems or limited to a certain spectrum of symbiotic interactions such as host-microbial coevolution? Critical discourse is necessary in this nascent area, but productive discourse requires that skeptics and proponents use the same lexicon. For instance, critiquing the hologenome concept is not synonymous with critiquing coevolution, and arguing that an entity is not a primary unit of selection dismisses the fact that the hologenome concept has always embraced multilevel selection. Holobionts and hologenomes are incontrovertible, multipartite entities that result from ecological, evolutionary, and genetic processes at various levels. They are not restricted to one special process but constitute a wider vocabulary and framework for host biology in light of the microbiome

    Subcutaneous Implant-based Breast Reconstruction with Acellular Dermal Matrix/Mesh

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    BACKGROUND: The availability of acellular dermal matrix (ADM) and synthetic mesh products has prompted plastic surgeons to revisit subcutaneous implant-based breast reconstruction. The literature is limited, however, with regards to evidence on patient selection, techniques, and outcomes. METHODS: A systematic review of the Medline and Cochrane databases was performed for original studies reporting breast reconstruction with ADM or mesh, and subcutaneous implant placement. Studies were analyzed for level of evidence, inclusion/exclusion criteria for subcutaneous reconstruction, reconstruction characteristics, and outcomes. RESULTS: Six studies (186 reconstructions) were identified for review. The majority of studies (66.7%) were level IV evidence case series. Eighty percent of studies had contraindications for subcutaneous reconstruction, most commonly preoperative radiation, high body mass index, and active smoking. Forty percent of studies commenting on patient selection assessed mastectomy flap perfusion for subcutaneous reconstruction. Forty-five percent of reconstructions were direct-to-implant, 33.3% 2-stage, and 21.5% single-stage adjustable implant, with ADM utilized in 60.2% of reconstructions versus mesh. Pooled complication rates included: major infection 1.2%, seroma 2.9%, hematoma 2.3%, full nipple-areola complex necrosis 1.1%, partial nipple-areola complex necrosis 4.5%, major flap necrosis 1.8%, wound healing complication 2.3%, explantation 4.1%, and grade III/IV capsular contracture 1.2%. CONCLUSIONS: Pooled short-term complication rates in subcutaneous alloplastic breast reconstruction with ADM or mesh are low in preliminary studies with selective patient populations, though techniques and outcomes are variable across studies. Larger comparative studies and better-defined selection criteria and outcomes reporting are needed to develop appropriate indications for performing subcutaneous implant-based reconstruction
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