16 research outputs found

    Fishes and other aquatic species in the Byzantine literature. Classification, terminology and scientific names.

    Get PDF
    Fishes and other aquatic species were substantial food in the every day life of Byzantine people. The predomination of Christianity contributed to the increased consumption of fishes and other seafood compared to the meat of land animals and chicken. More than a hundred ten names of fishes and about thirty names of other aquatic organisms are found in the sources of the Byzantine literature. Most frequent references are found in the medical texts of the Byzantine doctors, where, fishes are classified in categories depending on their physiology and origin, because, according to the writers, these are determining factors for the evaluation of the nutritional value of each species.The purpose of this study is to present the terminology of the fishes and the various aquatic species that are found in the Byzantine sources and to identify, in parallel, each species with its current scientific name.  Fishes and other aquatic species were substantial food in the every day life of Byzantine people. The predomination of Christianity contributed to the increased consumption of fishes and other seafood compared to the meat of land animals and chicken. More than a hundred ten names of fishes and about thirty names of other aquatic organisms are found in the sources of the Byzantine literature. Most frequent references are found in the medical texts of the Byzantine doctors, where, fishes are classified in categories depending on their physiology and origin, because, according to the writers, these are determining factors for the evaluation of the nutritional value of each species.The purpose of this study is to present the terminology of the fishes and the various aquatic species that are found in the Byzantine sources and to identify, in parallel, each species with its current scientific name. 

    NASA's Planned Return to the Moon: Global Access and Anytime Return Requirement Implications on the Lunar Orbit Insertion Burns

    Get PDF
    Lunar orbit insertion LOI is a critical maneuver for any mission going to the Moon. Optimizing the geometry of this maneuver is crucial to the success of the architecture designed to return humans to the Moon. LOI burns necessary to meet current NASA Exploration Constellation architecture requirements for the lunar sortie missions are driven mainly by the requirement for global access and "anytime" return from the lunar surface. This paper begins by describing the Earth-Moon geometry which creates the worst case (delta)V for both the LOI and the translunar injection (TLI) maneuvers over the full metonic cycle. The trajectory which optimizes the overall (delta)V performance of the mission is identified, trade studies results covering the entire lunar globe are mapped onto the contour plots, and the effects of loitering in low lunar orbit as a means of reducing the insertion (delta)V are described. Finally, the lighting conditions on the lunar surface are combined with the LOI and TLI analyses to identify geometries with ideal lighting conditions at sites of interest which minimize the mission (delta)V

    Dual Mission Scenarios for the Human Lunar Campaign - Performance, Cost and Risk Benefits

    Get PDF
    Scenarios for human lunar operations with capabilities significantly beyond Constellation Program baseline missions are potentially feasible based on the concept of dual, sequential missions utilizing a common crew and a single Ares I/CEV (Crew Exploration Vehicle). For example, scenarios possible within the scope of baseline technology planning include outpost-based sortie missions and dual sortie missions. Top level cost benefits of these dual sortie scenarios may be estimated by comparison to the Constellation Program reference two-mission-per-year lunar campaign. The primary cost benefit is the accomplishment of Mission B with a "single launch solution" since no Ares I launch is required. Cumulative risk to the crew is lowered since crew exposure to launch risks and Earth return risks are reduced versus comparable Constellation Program reference two-mission-per-year scenarios. Payload-to-the-lunar-surface capability is substantially increased in the Mission B sortie as a result of additional propellant available for Lunar Lander #2 descent. This additional propellant is a result of EDS #2 transferring a smaller stack through trans-lunar injection and using remaining propellant to perform a portion of the lunar orbit insertion (LOI) maneuver. This paper describes these dual mission concepts, including cost, risk and performance benefits per lunar sortie site, and provides an initial feasibility assessment

    Lunar Lander Offloading Operations Using a Heavy-Lift Lunar Surface Manipulator System

    Get PDF
    This study investigates the feasibility of using a heavy-lift variant of the Lunar Surface Manipulator System (LSMS-H) to lift and handle a 12 metric ton payload. Design challenges and requirements particular to handling heavy cargo were examined. Differences between the previously developed first-generation LSMS and the heavy-lift version are highlighted. An in-depth evaluation of the tip-over risk during LSMS-H operations has been conducted using the Synergistic Engineering Environment and potential methods to mitigate that risk are identified. The study investigated three specific offloading scenarios pertinent to current Lunar Campaign studies. The first involved offloading a large element, such as a habitat or logistics module, onto a mobility chassis with a lander-mounted LSMS-H and offloading that payload from the chassis onto the lunar surface with a surface-mounted LSMS-H. The second scenario involved offloading small pressurized rovers with a lander-mounted LSMS-H. The third scenario involved offloading cargo from a third-party lander, such as the proposed ESA cargo lander, with a chassis-mounted LSMS-H. In all cases, the analyses show that the LSMS-H can perform the required operations safely. However, Chariot-mounted operations require the addition of stabilizing outriggers, and when operating from the Lunar surface, LSMS-H functionality is enhanced by adding a simple ground anchoring system

    An Initial Comparison of Selected Earth Departure Options for Solar Electric Propulsion Missions

    No full text
    Earth departure options such as the location for deployment, aggregation, and crew rendezvous as well as the type of propulsion leveraged for each mission phase effect overall mission performance metrics such as number of critical maneuvers, mass of propellant to achieve departure, and initial mass required in low Earth orbit. This paper identifies and compares a subset of tactical options for deployment, crew rendezvous, and Earth departure that leverage electric propulsion and hybrid chemical electric propulsion with a goal of improving system efficiency. Departure maneuver specific limitations and penalties are then identified for missions to specific targets for human interplanetary missions providing a better understanding of the impact of decisions related to aggregation and rendezvous locations as well as Earth departure maneuvers on overall system performance

    The importance of addressing gender inequality in efforts to end vertical transmission of HIV

    No full text
    Issues: The recently launched “Global Plan towards the Elimination of New HIV Infections among Children by 2015 and Keeping their Mothers Alive” sets forth ambitious targets that will require more widespread implementation of comprehensive prevention of vertical HIV transmission (PMTCT) programmes. As PMTCT policymakers and implementers work toward these new goals, increased attention must be paid to the role that gender inequality plays in limiting PMTCT programmatic progress. Description: A growing body of evidence suggests that gender inequality, including gender-based violence, is a key obstacle to better outcomes related to all four components of a comprehensive PMTCT programme. Gender inequality affects the ability of women and girls to protect themselves from HIV, prevent unintended pregnancies and access and continue to use HIV prevention, care and treatment services. Lessons Learned: In light of this evidence, global health donors and international bodies increasingly recognize that it is critical to address the gender disparities that put women and children at increased risk of HIV and impede their access to care. The current policy environment provides unprecedented opportunities for PMTCT implementers to integrate efforts to address gender inequality with efforts to expand access to clinical interventions for preventing vertical HIV transmission. Effective community- and facility-based strategies to transform harmful gender norms and mitigate the impacts of gender inequality on HIV-related outcomes are emerging. PMTCT programmes must embrace these strategies and expand beyond the traditional focus of delivering ARV prophylaxis to pregnant women living with HIV. Without greater implementation of comprehensive, gender transformative PMTCT programmes, elimination of vertical transmission of HIV will remain elusive
    corecore