The influence of two estrogens on the sex and ovarian development of eastern oysters (Crassostrea virginica) maintained in a closed recirculating system

As a multi-million dollar industry, production of the eastern oyster Crassostrea virginica is significant to the economy of the nation’s coastal regions. The cost of commercial oyster aquaculture has higher inputs than the oyster fishery, but larger, better quality oysters can be produced for culture by the stable availability of triploid individuals. The goal of this project was to determine if the use of an estrogen, estradiol-17β or estradiol-3-benzoate, at a consistent environmental temperature would increase the percentage of females in a population, as well as ovarian development of eastern oysters. Ultimately, this could be applied to triploids to increase the number of viable oocytes produced for use in tetraploid induction. Tetraploids are used in direct triploid production to produce 100% triploid offspring when crossed with diploids. When estradiol-17β was administered to oysters obtained late in the spawning season (August), there was no significant change in sex distribution. The gonad-to-body ratios on day 10 were significantly greater than on day 14 (P \u3c 0.0001) and the stages of ovarian development in oysters treated with 150 ng differed from the other treatments (P = 0.002); significant differences were also seen between days 10 and 14 in this treatment (150 ng; P = 0.004). When estradiol-3-benzoate was administered to out-of-season oysters obtained in February prior to the spawning season, there was a significant difference in sex distribution from days 10 to 14 between the non-injected control (P = 0.030) and 37.5 ng treatment (P = 0.010). There was not enough gonadal tissue to calculate the gonad-to-body ratio, but there were no significant differences in the stages of ovarian development. Overall, the decrease in ovarian size over time is indicative of exogenous factors negatively affecting gonadal development. By increased management of factors such as high nutrient availability and decreased stress during transport and hormone administration could improve the response to estrogen treatment. Due to the short half-life of estrogens in vivo, a sustained-release system could also increase the treatment efficacy. Under the present conditions, there was not a clear, predictable effect of either estrogen on increasing gonadal development, maturity, or sex

An investigation into the limitations of low temperature district heating on traditional tenement buildings in Scotland

Domestic heating accounts for 64% of domestic energy usage in the UK, yet there are currently very few viable options for low carbon residential heating. The government’s carbon plan commits to improving the uptake of district heating connections in new build dwellings, but the greatest carbon saving can be made through targeting traditional housing stock. This paper aims to quantify the potential carbon and energy savings that can be made by connecting a traditional tenement building to a district heating scheme. The study uses a transient system simulation tool (TRNSYS) model to simulate the radiator system in a tenement block and shows that a significant benefit can be achieved by reducing the supply temperature; however, the minimum supply temperature is drastically limited by the building condition. Therefore, the study also critically compares the benefits of a lower supply temperature against minor refurbishments. It was found that improving building conditions alone could offer a 30% reduction in space heating energy consumption, while building improvements and integration of a river source heat pump could offer almost a 70% reduction. It is the recommendation of this study that a dwelling be improved as much as economically possible to achieve the greatest carbon and energetic savings

Bloodhound: Searching Out Malicious Input in Network Flows for Automatic Repair Validation

Many current systems security research efforts focus on mechanisms for Intrusion Prevention and Self-Healing Software. Unfortunately, such systems find it difficult to gain traction in many deployment scenarios. For self-healing techniques to be realistically employed, system owners and administrators must have enough confidence in the quality of a generated fix that they are willing to allow its automatic deployment. In order to increase the level of confidence in these systems, the efficacy of a 'fix' must be tested and validated after it has been automatically developed, but before it is actually deployed. Due to the nature of attacks, such verification must proceed automatically. We call this problem Automatic Repair Validation (ARV). As a way to illustrate the difficulties faced by ARV, we propose the design of a system, Bloodhound, that tracks and stores malicious network flows for later replay in the validation phase for self-healing softwar

Bloodhound: Searching Out Malicious Input in Network Flows for Automatic Repair Validation

Many current systems security research efforts focus on mechanisms for Intrusion Prevention and Self-Healing Software. Unfortunately, such systems find it difficult to gain traction in many deployment scenarios. For self-healing techniques to be realistically employed, system owners and administrators must have enough confidence in the quality of a generated fix that they are willing to allow its automatic deployment. In order to increase the level of confidence in these systems, the efficacy of a 'fix' must be tested and validated after it has been automatically developed, but before it is actually deployed. Due to the nature of attacks, such verification must proceed automatically. We call this problem Automatic Repair Validation (ARV). As a way to illustrate the difficulties faced by ARV, we propose the design of a system, Bloodhound, that tracks and stores malicious network flows for later replay in the validation phase for self-healing softwar

Molecular Photovoltaics and Nanocrystalline Junctions

Photosensitization of wide-band-gap semiconductors is a promising low-cost photovoltaic technology. We present herein recent advances in photovoltaic devices and related technologies which have been achieved at the Laboratory for Photonics and Interfaces of the EPFL. New photosensitizing molecules have been developed which exhibit an increased spectral response. Semiconductor oxide nanoparticles used in the formation of thin-film photoelectrodes self-organize in a cubic array. Additionally, prototypes of small devices powered by dye-sensitized photovoltaic devices are now appearing

A latitudinal cline in the efficacy of endogenous signals: evidence derived from retinal cone contraction in fish.

Like many physiological systems synchronised to the light:dark cycle, retinomotor movements in 'lower' vertebrates are controlled by both the ambient illumination and input from endogenous circadian oscillators. In the present study, we examine the relative influence of these two signals in various species of teleost fish with different latitudes of origin. We find equatorial species show very strong endogenous control. The cones of the glowlight tetra, for example, continue to go through undiminished cycles of contraction and relaxation that mirror the previous light:dark cycle for at least two weeks in continual darkness. To quantify the relative effectiveness of the ambient light compared with endogenous signals in causing cone contraction, the degree to which seven teleost species responded to light during the dark phase of their light:dark cycle was examined. In this situation the retina receives conflicting instructions; while the light is acting directly to cause light adaptation, any endogenous signal tends to keep the retinal elements dark adapted. The further from the equator a species originated, the more its cones contracted in response to such illumination, suggesting animals from higher latitudes make little use of endogenous oscillators and rely more on ambient illumination to control behaviours. Equatorial species, however, rely on internal pacemakers to a much greater degree and are relatively insensitive to exogenous light signals. Because these data are consistent with published observations in systems as diverse as melatonin synthesis in Arctic reindeer and the behaviour of regional populations of Drosophila, latitudinal clines in the efficacy of circadian oscillators may be a common feature among animals

Análisis de los factores que afectan la implementación de diversos métodos de financiación para proyectos de fuentes no convencionales de energía renovable (FNCER) en Colombia.

Esta investigación analiza múltiples factores que sirven como potenciadores para lograr una financiación y operación más amigable en términos económicos y de riesgo tanto para los desarrolladores de proyectos de energía basada en FNCER como para quienes intervienen en estos con recursos financieros y de riesgo. La favorabilidad de las condiciones climáticas y geográficas de Colombia, el músculo financiero y la experiencia de las grandes compañías de generación, los diferentes instrumentos de transferencia de riesgo como los derivados climáticos y la solidificación de métodos de financiación como el Project Finance y los Bonos Verdes son los puntos que son abordados en la investigación que contribuirían a la mitigación de los riesgos y dificultades de financiación que se perciben en los proyectos de generación de energía basados en FNCER.1. Revisión de la literatura ; Introducción ; Definición de variables ; Energías renovables en Colombia ; Financiación de proyectos de generación de energía renovable no convencional ; Estado del arte ; 2. Metodología ; Diseño de la investigación ; Fase 1; Fase 2 ; Fase 3 ; Variables de investigación ; 3. Resultados Obtenidos ; Análisis de la situación actual del sector energético en Colombia ; Análisis del rol de las empresas energéticas en el desarrollo de proyectos de energía sostenible en Colombia ; Análisis de los métodos de financiación e inversión aplicados para el desarrollo de proyectos de energía sostenible en Colombia ; Conclusiones Recomendaciones.Administrador de EmpresasPregrad

Fiscal policy and indeterminacy in models of endogenous growth

This paper investigates the dynamic behavior of two-sector models of endogenous growth with sector-specific external effects, and government expenditure financed by distortionary taxation. When this type of external effect is combined with a sufficient degree of capital taxation in a Lucas–Uzawa endogenous growth model, continua of equilibria will emerge in the region of the balanced growth paths. By contrast, indeterminacy is not possible when either sector-specific external effects or factor taxation are added to the model in isolation. In the second part of the paper, we demonstrate that if labor supply is endogenous, indeterminacy can be consistent with much lower degrees of increasing returns to scale. Furthermore, certain types of fiscal policy will be associated with multiple balanced growth paths and the existence of a poverty trap. Finally, in the last part of the paper, we demonstrate that if physical capital is employed in both sectors of the economy, indeterminacy will emerge for varying combinations of factor taxation and external effects, even when returns to scale are constant at the social level

Online Network Forensics for Automatic Repair Validation

Automated intrusion prevention and self-healing software are active areas of security systems research. A major hurdle for the widespread deployment of these systems is that many system administrators lack confidence in the quality of the generated fixes. Thus, a key requirement for future self-healing software is that each automatically-generated fix must be validated before deployment. Under the response rates required by self-healing systems, we believe such verification must proceed automatically. We call this process Automatic Repair Validation (ARV). We describe the design and implementation of Bloodhound, a system that tags and tracks information between the kernel and the application and correlates symptoms of exploits (such as memory errors) with high-level data (e.g., network flows). By doing so, Bloodhound can replay the flows that triggered the repair process against the newly healed application to help show that the repair is accurate (i.e., it defeats the exploit). We show through experimentation a performance impact of as little as 2.6%