Probabilistic Assessment of Radiation Risk for Astronauts in Space Missions

Accurate predictions of the health risks to astronauts from space radiation exposure are necessary for enabling future lunar and Mars missions. Space radiation consists of solar particle events (SPEs), comprised largely of medium energy protons, (less than 100 MeV); and galactic cosmic rays (GCR), which include protons and heavy ions of higher energies. While the expected frequency of SPEs is strongly influenced by the solar activity cycle, SPE occurrences themselves are random in nature. A solar modulation model has been developed for the temporal characterization of the GCR environment, which is represented by the deceleration potential, phi. The risk of radiation exposure from SPEs during extra-vehicular activities (EVAs) or in lightly shielded vehicles is a major concern for radiation protection, including determining the shielding and operational requirements for astronauts and hardware. To support the probabilistic risk assessment for EVAs, which would be up to 15% of crew time on lunar missions, we estimated the probability of SPE occurrence as a function of time within a solar cycle using a nonhomogeneous Poisson model to fit the historical database of measurements of protons with energy > 30 MeV, (phi)30. The resultant organ doses and dose equivalents, as well as effective whole body doses for acute and cancer risk estimations are analyzed for a conceptual habitat module and a lunar rover during defined space mission periods. This probabilistic approach to radiation risk assessment from SPE and GCR is in support of mission design and operational planning to manage radiation risks for space exploration

Time Serial Analysis of the Induced LEO Environment within the ISS 6A

Anisotropies in the low Earth orbit (LEO) radiation environment were found to influence the thermoluminescence detectors (TLD) dose within the (International Space Station) ISS 7A Service Module. Subsequently, anisotropic environmental models with improved dynamic time extrapolation have been developed including westward and northern drifts using AP8 Min & Max as estimates of the historic spatial distribution of trapped protons in the 1965 and 1970 era, respectively. In addition, a directional dependent geomagnetic cutoff model was derived for geomagnetic field configurations from the 1945 to 2020 time frame. A dynamic neutron albedo model based on our atmospheric radiation studies has likewise been required to explain LEO neutron measurements. The simultaneous measurements of dose and dose rate using four Liulin instruments at various locations in the US LAB and Node 1 has experimentally demonstrated anisotropic effects in ISS 6A and are used herein to evaluate the adequacy of these revised environmental models

Pre-engineering Spaceflight Validation of Environmental Models and the 2005 HZETRN Simulation Code

The HZETRN code has been identified by NASA for engineering design in the next phase of space exploration highlighting a return to the Moon in preparation for a Mars mission. In response, a new series of algorithms beginning with 2005 HZETRN, will be issued by correcting some prior limitations and improving control of propagated errors along with established code verification processes. Code validation processes will use new/improved low Earth orbit (LEO) environmental models with a recently improved International Space Station (ISS) shield model to validate computational models and procedures using measured data aboard ISS. These validated models will provide a basis for flight-testing the designs of future space vehicles and systems of the Constellation program in the LEO environment

Complement Inhibition Promotes Endogenous Neurogenesis and Sustained Anti-Inflammatory Neuroprotection following Reperfused Stroke

The restoration of blood-flow following cerebral ischemia incites a series of deleterious cascades that exacerbate neuronal injury. Pharmacologic inhibition of the C3a-receptor ameliorates cerebral injury by attenuating post-ischemic inflammation. Recent reports also implicate C3a in the modulation of tissue repair, suggesting that complement may influence both injury and recovery at later post-ischemic time-points.To evaluate the effect of C3a-receptor antagonism on post-ischemic neurogenesis and neurological outcome in the subacute period of stroke, transient focal cerebral ischemia was induced in adult male C57BL/6 mice treated with multiple regimens of a C3a receptor antagonist (C3aRA).Low-dose C3aRA administration during the acute phase of stroke promotes neuroblast proliferation in the subventricular zone at 7 days. Additionally, the C3a receptor is expressed on T-lymphocytes within the ischemic territory at 7 days, and this cellular infiltrate is abrogated by C3aRA administration. Finally, C3aRA treatment confers robust histologic and functional neuroprotection at this delayed time-point.Targeted complement inhibition through low-dose antagonism of the C3a receptor promotes post-ischemic neuroblast proliferation in the SVZ. Furthermore, C3aRA administration suppresses T-lymphocyte infiltration and improves delayed functional and histologic outcome following reperfused stroke. Post-ischemic complement activation may be pharmacologically manipulated to yield an effective therapy for stroke

Excitation of Large-amplitude Plasma-waves In A Plasma Filled Open Resonator

It is shown that resonant excitation of large amplitude (>or approximately=10^4 V cm^(-1) ) plasma waves is possible through the beating of two microwaves of nearly equal frequencies in an 'open' resonator filled with plasma of subcritical density. Detailed calculation are presented of the configuration, growth and saturation of the pump and plasma waves in the resonant cavity

Cap. 6 Settore Robotics (in Innovazione e Valore. Automotive, Robotics)

Il saggio inaugura una nuova sezione della Collana di Finanza Aziendale dell'Università di Roma "La Sapienza": Trends and Value, dedicata all’osservazione delle nuove tendenze innescate da innovazioni scientifiche, tecnologiche e industriali, capaci di provocare importanti e duraturi cambiamenti nei economici e sociali. Le imprese capaci di produrre innovazioni (nel senso più ampio) dovrebbero godere di vantaggi rispetto ai competitori e quindi – se quotate – essere maggiormente apprezzate dai mercati finanziari. Ci si chiede: quando emerge tale vantaggio competitivo? E’ rilevato prima dai risultati aziendali o dalle quotazioni dei titoli azionari delle società? Quanto dura il suo beneficio e quanto è difendibile? Il programma di ricerca, che qui si presenta con i suoi primi risultati, tenta di rispondere a tali domande indagando il tema, piuttosto ampio, delle relazioni tra innovazioni e valore delle imprese. Dalle analisi empiriche ci si attende che i gruppi societari leader nei rispettivi settori, che in molti casi sono anche gli agenti dell’innovazione, risultino anche i maggiori beneficiari – in termini di vantaggio competitivo e di prospettive di sviluppo – dei cambiamenti, rispetto altre imprese che si limitano a seguire tali orientamenti. I primi risultati relativi ai settori Automotive e Robotics non confermano sempre questa aspettativa.This essay opens a new section of the series of Corporate Finance of the "Sapienza" University of Rome, named "Trends and Value" and dedicated to the observation of new trends triggered by innovations in science, technology and industry, which cause significant and lasting changes in economy and society. Companies able to producing innovations should take advantages over competitors and then - if listed - be evaluated by the financial markets. But, the questions are: when emerges that competitive advantage? Is this advantage detectable before by the firm's performances or by the share prices of the firm? How long are its benefits and how is defensible? The research program, presented here, with its first results, try to answer these questions by investigating the relationship between innovation and firm’s value creation. The expectation of the empirical analysis is that the leaders in their respective sectors, which in many cases are also agents of innovation, prove also the biggest b

Developing of a New Atmospheric Ionizing Radiation (AIR) Model

As a result of the research leading to the 1998 AIR workshop and the subsequent analysis, the neutron issues posed by Foelsche et al. and further analyzed by Hajnal have been adequately resolved. We are now engaged in developing a new atmospheric ionizing radiation (AIR) model for use in epidemiological studies and air transportation safety assessment. A team was formed to examine a promising code using the basic FLUKA software but with modifications to allow multiple charged ion breakup effects. A limited dataset of the ER-2 measurements and other cosmic ray data will be used to evaluate the use of this code