WorldWideScience

Sample records for risky business asteroid

  1. Risky Business

    Science.gov (United States)

    Yarbrough, Katherine

    2015-01-01

    During my internship I worked on two major projects, recommending improvements for the Center's Risk Management Workshop and helping with the strategic planning efforts for Safety and Mission Assurance (S&MA). The risk management improvements is the key project I worked on this semester through my internship, while the strategic planning is the secondary assignment. S&MA Business Office covers both aspects in its delegation, getting both spans some of the work done in the office. A risk is a future event with a negative consequence that has some probability of occurring. Safety and Mission Assurance identifies, analyzes, plans, and tracks risk. The directorate offers the Center a Risk Management Workshop, and part of the ongoing efforts of S&MA is to make continuous improvements to the RM Workshop. By using the Project Management Institute's (PMI) Standard for Risk Management, I performed a gap analysis to make improvements for our materials. I benchmarked the PMI's Risk Management Standard, compared our Risk Management Workshop materials to PMI's standard, and identified any gaps in our material. My major findings were presented to the Business Office of S&MA for a decision on whether or not to incorporate the improvements. These suggestions were made by attending JSC working group meetings, Health, Safety and Environment (HSE) panel reviews and various risk review meetings. The improvements provide better understanding of risk management processes and enhanced risk tracking knowledge and skills. Risk management is an integral part of any engineering discipline, getting exposed to this section of engineering will greatly help shape my career in the future. Johnson Space Center is a world leader in risk management processes; learning risk management here gives me a huge advantage over my peers, as well as understanding decision making in the context of risk management will help me to be a well-rounded engineer. Strategic planning is an area I had not previously

  2. Social enterprise. Risky business.

    Science.gov (United States)

    2007-02-15

    The skills needed to run a social enterprise are similar to those needed for conventional business. Accounts for social enterprises will have a 'double bottom line', showing social benefit as well as profit. Finding a good mentor is vital, as is setting out a clear vision and values in your business plan.

  3. A Risky Business?

    DEFF Research Database (Denmark)

    Blasco, Maribel

    2003-01-01

    The paper looks at initiatives taken by the Mexican Employers' Confederation (COPARMEX)aimed at promoting collaboration among civil society associations around the issue of publicsafety. Insecurity in the form of robbery, assault and kidnapping causes huge losses to business inMexico. It is argued...... that business leaders are seeking to create consensus and form alliancesamong civil society around the topic of insecurity, both to combat crime but also as a strategy tostrengthen links with civil society and improve the image of business, which has suffered due to theincreasing resonance of anti...

  4. A Risky Business?

    OpenAIRE

    Blasco, Maribel

    2003-01-01

    The paper looks at initiatives taken by the Mexican Employers’ Confederation (COPARMEX) aimed at promoting collaboration among civil society associations around the issue of public safety. Insecurity in the form of robbery, assault and kidnapping causes huge losses to business in Mexico. It is argued that business leaders are seeking to create consensus and form alliances among civil society around the topic of insecurity, both to combat crime but also as a strategy to strength...

  5. Risky business: how insurance companies gamble with your health coverage.

    Science.gov (United States)

    Denny, J

    1993-01-01

    Under a patchwork of state laws and virtually no federal oversight, a decade of risky investments, questionable business dealings, lavish spending, and help-yourself ethics in the insurance industry is playing a hidden role in the crisis in affordable medical coverage. Skyrocketing medical costs are the main culprit, but financial losses have put pressure on insurers to raise premiums and cancel risky policyholders. The losses also are a major factor in the sharp increase in life/health insurance company failures, which can leave policyholders stranded.

  6. Risky business: When humor increases and decreases status.

    Science.gov (United States)

    Bitterly, T Bradford; Brooks, Alison Wood; Schweitzer, Maurice E

    2017-03-01

    Across 8 experiments, we demonstrate that humor can influence status, but attempting to use humor is risky. The successful use of humor can increase status in both new and existing relationships, but unsuccessful humor attempts (e.g., inappropriate jokes) can harm status. The relationship between the successful use of humor and status is mediated by perceptions of confidence and competence. The successful use of humor signals confidence and competence, which in turn increases the joke teller's status. Interestingly, telling both appropriate and inappropriate jokes, regardless of the outcome, signals confidence. Although signaling confidence typically increases status and power, telling inappropriate jokes signals low competence and the combined effect of high confidence and low competence harms status. Rather than conceptualizing humor as a frivolous or ancillary behavior, we argue that humor plays a fundamental role in shaping interpersonal perceptions and hierarchies within groups. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  7. Risky business.

    Science.gov (United States)

    Baram, M

    1996-10-01

    In prior studies by high-level commissions, emphasis was given to improving the scientific basis and institutional procedures for risk assessment and risk regulation within existing statutory frameworks. Recommendations have led to slow but steady progress. This study is considerably different. It emphasizes a public health approach for efficient use of resources in a new flexible framework for risk management, reductionist approaches to risk assessment and characterization, increased public involvement, and various methods for managing such public involvement. It provides a mix of aspirations and concepts, procedures, and "shop floor rules" for putting the new system of risk management into practice. Concerns remain, however, that bright lines and other rules are at odds with the report's professed aspirations for meaningful public involvement; that ad hoc institutional arrangements for putting each risk in a situational context may not be an efficient use of public and private resources; that techniques for managing stakeholder involvement will be seen as manipulative and may even increase public mistrust and anxieties about risk; and that reductionism by the regulatory clients of risk assessment could diminish progress in the environmental health sciences. Says Lucier, "The goal of risk assessment should be to prevent environmentally or occupationally mediated diseases or injury. This point is not made sufficiently clear in the commission's report. Nevertheless, the report does an admirable job of attempting to merge science, common sense, public perception, public health, economics, and stakeholder interests into a regulatory policy strategy." He continues, "The merging of these diverse inputs will never be easy and should never be overly prescriptive. The complete integration of all relevant information into the risk assessment and risk management process will require greater reliance on expert judgment to make decisions that are timely, that are based on appropriate peer review, that are consistent with public health priorities, that do not create unnecessary regulatory burdens, and that are understandable by the public." The commission's report provides an alternative vision of risk management that incorporates popular political and social trends. Thorough evaluation of the report's recommendations will, at the very least, focus scrutiny on current risk assessment and risk management practices and perhaps produce better solutions.

  8. Risky Business.

    Science.gov (United States)

    Smith, Sean

    2001-01-01

    Illustrates how schools and universities can control their insurance costs in an unfavorable economic climate. Cost control strategies discussed include risk retention, loss control, procedural documentation, and pooled resources. (GR)

  9. Risky Business and the American Climate Prospectus: Economic Risks of Climate Change in the United States"

    Science.gov (United States)

    Gordon, K.; Houser, T.; Kopp, R. E., III; Hsiang, S. M.; Larsen, K.; Jina, A.; Delgado, M.; Muir-Wood, R.; Rasmussen, D.; Rising, J.; Mastrandrea, M.; Wilson, P. S.

    2014-12-01

    The United States faces a range of economic risks from global climate change - from increased flooding and storm damage, to climate-driven changes in crop yields and labor productivity, to heat-related strains on energy and public health systems. The Risky Business Project commissioned a groundbreaking new analysis of these and other climate risks by region of the country and sector of the economy. The American Climate Prospectus (ACP) links state-of-the-art climate models with econometric research of human responses to climate variability and cutting edge private sector risk assessment tools, the ACP offers decision-makers a data driven assessment of the specific risks they face. We describe the challenge, methods, findings, and policy implications of the national risk analysis, with particular focus on methodological innovations and novel insights.

  10. ASTEROIDS

    Directory of Open Access Journals (Sweden)

    Željko Andreić

    2016-02-01

    Full Text Available Asteroids are the largest minor bodies in the Solar System. Nowadays they are in the research focus due to several facts about them: first, a subclass of asteroids can collide with Earth, and consequences of such a collision are dramatic. Second, they are now seen as source of materials that are becoming scarce on Earth, and they will be needed in future space constructions anyway. Third, they are holding clues about the origin and evolution of the Solar System. In this article, a short overview of current knowledge about asteroids is presented. Last, but not least, as several Croatian scientists were recently honored by naming an asteroid after them, a short overview of the naming process is given.

  11. ASTEROIDS

    OpenAIRE

    Željko Andreić

    2016-01-01

    Asteroids are the largest minor bodies in the Solar System. Nowadays they are in the research focus due to several facts about them: first, a subclass of asteroids can collide with Earth, and consequences of such a collision are dramatic. Second, they are now seen as source of materials that are becoming scarce on Earth, and they will be needed in future space constructions anyway. Third, they are holding clues about the origin and evolution of the Solar System. In this article, a short overv...

  12. Politics, policy & risky business

    OpenAIRE

    Brockdorff, Noellie; Bajada, Claude

    2016-01-01

    As a child, Prof. Noellie Brockdorff was fascinated by the robots that inhabited the world of Isaac Asimov’s novels. She wanted to know why humans are different to robots. So why are human beings not perfectly rational creatures like robots? Dr Claude Bajada finds out more.

  13. How to establish knowledge sharing from the very first moment in critical and risky Business Model Innovation project

    DEFF Research Database (Denmark)

    Lindgren, Peter; Ulldall, Lena; Aagaard, Annabeth

    Joint action and knowledge sharing are fundamental aspects of business model innovation for businesses to meet the complex Business Model Innovation challenges; for example, think about 12 business jointly innovating on the establishment of a new concept of a balanced energy plant project where...

  14. How to establish knowledge sharing from the very first moment in critical and risky Business Model Innovation project

    DEFF Research Database (Denmark)

    Lindgren, Peter; Ulldall, Lena; Aagaard, Annabeth

    Joint action and knowledge sharing are fundamental aspects of business model innovation for businesses to meet the complex Business Model Innovation challenges; for example, think about 12 business jointly innovating on the establishment of a new concept of a balanced energy plant project where...... the business have to work in symbioses; 5 interdiciplinary groups innovating on 5 very different and complex businesses business model challenge and 22 independent business collaborative innovation on the establishment of a new Business Model Innovation incubator platform. Yet, cognitive science and best...... first moment of the meeting between the involved different participants – who often are unknown to each other. It lays the fundament for knowledge sharing and learning to the Business Model Innovation project – and the ground for whether the BMI project will succeed and be implemented. The paper aims...

  15. Asteroid structure

    Science.gov (United States)

    Asphaug, E.

    2014-07-01

    Even before the first space missions to asteroids, in the mid-1990s, it was known that asteroids have weird structures. Photometry indicated complicated shapes, and the pioneering radar investigations by Ostro and colleagues followed by adaptive optics campaigns and flybys showed odd binary forms, and confirmed the common presence of satellites, and indications of highly varying surface roughness. Some asteroids turned out to be dominated by a single major cratering event, while others showed no evidence of a major crater, or perhaps for global crater erasure. The first space mission to orbit an asteroid, NEAR, found a mixture of heavily cratered terrains and geomorphically active 'ponds', and indicated evidence for global seismicity from impact. The next mission to orbit an asteroid, Hayabusa, found what most agree is a rubble pile, with no major craters and an absence of fines. There is to date no direct evidence of asteroid interior geology, other than measurements of bulk density, and inferences made for mass distribution asymmetry based on dynamics, and inferences based on surface lineaments. Interpolating from the surface to the interior is always risky and usually wrong, but of course the answer is important since we are someday destined to require this knowledge in order to divert a hazardous asteroid from impact with the Earth. Even considering the near-subsurface, here we remain as ignorant as we were about the Moon in the early 1960s, whether the surface will swallow us up in dust, or will provide secure landing and anchoring points. Laboratory experimentation in close to zero-G is still in its early stages. Adventures such as mining and colonization will surely have to wait until we better know these things. How do we get from here to there? I will focus on 3 areas of progress: (1) asteroid cratering seismology, where we use the surface craters to understand what is going on inside; (2) numerical modeling of collisions, which predicts the internal

  16. Strategies for a risky business: How drug dealers manage customers, suppliers and competitors in Italy, Slovenia and Germany.

    Science.gov (United States)

    Tzvetkova, Marina; Pardal, Mafalda; Disley, Emma; Rena, Alice; Talic, Sanela; Forberger, Sarah

    2016-05-01

    A growing body of literature aims to improve understanding of the operations of drug trafficking markets through conducting interviews with dealers and traffickers. Insight into how these individuals conduct business can provide evidence to inform the efforts by policy makers, law enforcement and practitioners to disrupt illicit markets. This paper aims to make a contribution to this evidence base by extending the number of European countries in which interviews have been conducted with incarcerated drug dealers and traffickers. It draws on interviews with 135 men convicted of offences related to the distribution or sale of heroin or cocaine and imprisoned in Italy, Slovenia and Germany. The research was conducted as part of the Reframing Addictions Project (ALICE-RAP) funded by the European Commission. The sample was diverse. It included a range of nationalities and some individuals who were members of organised crime groups. The majority of the interviewees were dealers who sold at the retail and street level, but there were some who were importers and wholesalers. Most dealers in each of the three countries reported having more than one regular supplier, and were able to respond to periods of over and under supply without losing customers. Supply arrangements varied in terms of frequency and quantities bought. Dealers engaged in repeated transactions and their relationships with customers were based on trust and reputation. Dealers aimed to sell to regular customers and to provide drugs of good quality. While dealers sought to maximise their profits by cutting drugs with cutting agents, the quality of drugs that they sold could affect their reputation and thus their profits and position in the market. Lastly, while there are some significant differences in the approach between those involved in organised crime groups and those who are not, and between street dealers and those operating at higher levels of the market, there were striking similarities in terms of

  17. Asteroid mining

    Science.gov (United States)

    Gertsch, Richard E.

    1992-01-01

    The earliest studies of asteroid mining proposed retrieving a main belt asteroid. Because of the very long travel times to the main asteroid belt, attention has shifted to the asteroids whose orbits bring them fairly close to the Earth. In these schemes, the asteroids would be bagged and then processed during the return trip, with the asteroid itself providing the reaction mass to propel the mission homeward. A mission to one of these near-Earth asteroids would be shorter, involve less weight, and require a somewhat lower change in velocity. Since these asteroids apparently contain a wide range of potentially useful materials, our study group considered only them. The topics covered include asteroid materials and properties, asteroid mission selection, manned versus automated missions, mining in zero gravity, and a conceptual mining method.

  18. Foundation Degrees: A Risky Business?

    Science.gov (United States)

    Rowley, Jennifer

    2005-01-01

    Purpose: Foundation degrees, the new proposal for sub-degree vocational education in the UK, are characterised by innovation both in their design (curriculum, teaching, learning and assessment) and in the marketplace for which they are designed. This article argues that the development and delivery of foundation degrees carry a high level of risk,…

  19. Risky Business: Students and Smartphones

    Science.gov (United States)

    Jones, Beth H.; Chin, Amita Goyal; Aiken, Peter

    2014-01-01

    The increase in smartphone adoption has been no less than astounding. Unfortunately, the explosive growth has been accompanied by a rash of security problems. A contributing factor to the growing security problem is a lack of education, training, and awareness. In addition, "bring your own device" (BYOD) policies often leave security…

  20. Risky Business: Students and Smartphones

    Science.gov (United States)

    Jones, Beth H.; Chin, Amita Goyal; Aiken, Peter

    2014-01-01

    The increase in smartphone adoption has been no less than astounding. Unfortunately, the explosive growth has been accompanied by a rash of security problems. A contributing factor to the growing security problem is a lack of education, training, and awareness. In addition, "bring your own device" (BYOD) policies often leave security…

  1. Asteroid Redirect

    OpenAIRE

    De Aquino, Fran

    2017-01-01

    Asteroids are a great threat to mankind. Here we will show that it is possible to redirect them from their trajectories by means of a strong gravitational repulsion, produced by the gravitational interaction between the asteroid and a Gravitational Spacecraft positioned close to the asteroid.

  2. Asteroid Photometry

    CERN Document Server

    Li, Jian-Yang; Buratti, Bonnie J; Takir, Driss; Clark, Beth Ellen

    2015-01-01

    Asteroid photometry has three major applications: providing clues about asteroid surface physical properties and compositions, facilitating photometric corrections, and helping design and plan ground-based and spacecraft observations. The most significant advances in asteroid photometry in the past decade were driven by spacecraft observations that collected spatially resolved imaging and spectroscopy data. In the mean time, laboratory measurements and theoretical developments are revealing controversies regarding the physical interpretations of models and model parameter values. We will review the new developments in asteroid photometry that have occurred over the past decade in the three complementary areas of observations, laboratory work, and theory. Finally we will summarize and discuss the implications of recent findings.

  3. Asteroid taxonomy

    Science.gov (United States)

    Tholen, David J.; Barucci, M. Antonietta

    1989-01-01

    The spectral reflectivity of asteroid surfaces over the wavelength range of 0.3 to 1.1 micron can be used to classify these objects into several broad groups with similar spectral characteristics. The three most recently developed taxonomies group the asteroids into 9, 11, or 14 different clases, depending on the technique used to perform the analysis. The distribution of the taxonomic classes shows that darker and redder objects become more dominant at larger heliocentric distances, while the rare asteroid types are found more frequently among the small objects of the planet-crossing population.

  4. Asteroids IV

    Science.gov (United States)

    Michel, Patrick; DeMeo, Francesca E.; Bottke, William F.

    Asteroids are fascinating worlds. Considered the building blocks of our planets, many of the authors of this book have devoted their scientific careers to exploring them with the tools of our trade: ground- and spacebased observations, in situ space missions, and studies that run the gamut from theoretical modeling efforts to laboratory work. Like fossils for paleontologists, or DNA for geneticists, they allow us to construct a veritable time machine and provide us with tantalizing glimpses of the earliest nature of our solar system. By investigating them, we can probe what our home system was like before life or even the planets existed. The origin and evolution of life on our planet is also intertwined with asteroids in a different way. It is believed that impacts on the primordial Earth may have delivered the basic components for life, with biology favoring attributes that could more easily survive the aftermath of such energetic events. In this fashion, asteroids may have banished many probable avenues for life to relative obscurity. Similarly, they may have also prevented our biosphere from becoming more complex until more recent eras. The full tale of asteroid impacts on the history of our world, and how human life managed to emerge from myriad possibilities, has yet to be fully told. The hazard posed by asteroid impacts to our civilization is low but singular. The design of efficient mitigation strategies strongly relies on asteroid detection by our ground- and spacebased surveys as well as knowledge of their physical properties. A more positive motivation for asteroid discovery is that the proximity of some asteroids to Earth may allow future astronauts to harvest their water and rare mineral resources for use in exploration. A key goal of asteroid science is therefore to learn how humans and robotic probes can interact with asteroids (and extract their materials) in an efficient way. We expect that these adventures may be commonplace in the future

  5. Small asteroid system evolution

    OpenAIRE

    Jacobson, Seth A.

    2014-01-01

    Observations with radar, photometric and direct imaging techniques have discovered that multiple asteroid systems can be divided clearly into a handful of different morphologies, and recently, the discovery of small unbound asteroid systems called asteroid pairs have revolutionized the study of small asteroid systems. Simultaneously, new theoretical advances have demonstrated that solar radiation dictates the evolution of small asteroids with strong implications for asteroid internal structur...

  6. Small asteroid system evolution

    OpenAIRE

    Jacobson, Seth A.

    2014-01-01

    Observations with radar, photometric and direct imaging techniques have discovered that multiple asteroid systems can be divided clearly into a handful of different morphologies, and recently, the discovery of small unbound asteroid systems called asteroid pairs have revolutionized the study of small asteroid systems. Simultaneously, new theoretical advances have demonstrated that solar radiation dictates the evolution of small asteroids with strong implications for asteroid internal structur...

  7. Search for Asteroid-Asteroid Encounters

    Directory of Open Access Journals (Sweden)

    Luis A. Mammana

    2001-01-01

    Full Text Available Earlier studies about asteroids did not consider mutual interactions since they assume a negligible asteroid mass. In 1966 Hertz took into account for the first time the gravitational effects produced by an asteroid on another for mass determination. This gravitational action becomes relevant for enough effective encounters. The most efficient gravitational interaction is that produced in a large time interval and for small distances. For each particular caseful it is relevant to perform a care analysis in order to determinate the feasibility in the mass determination and improved orbital elements. In the present paper we performed a search of asteroid-asteroid encounters occurred in the twenty century for the first 3000 numbered asteroids . Of all encounters we have selected only those asteroid pairs in which one of the asteroids has a diameter larger than 200 km and the other one (the smaller an observational interval of at least ten years.

  8. Manuel Ocaña: risky business

    OpenAIRE

    2007-01-01

    El volumen Excepto 18 muestra argumentos de trabajo de la práxis de la oficina de Manuel Ocaña y su metodología de investigación aplicada a la trasladación del simbolismo en la forma arquitectónica. SIN FINANCIACIÓN No data (2007) UEM

  9. The Risky Business of Doctoral Management

    Science.gov (United States)

    McWilliam, Erica; Sanderson, Don; Evans, Terry; Lawson, Alan; Taylor, Peter G.

    2006-01-01

    Universities are under no less pressure to adopt risk management strategies than other public and private organisations. The risk management of doctoral education is a particularly important issue given that a doctorate is the highest academic qualification a university offers and stakes are high in terms of assuring its quality. However, intense…

  10. An ISU study of asteroid mining

    Science.gov (United States)

    Burke, J. D.

    1991-01-01

    During the 1990 summer session of the International Space University, 59 graduate students from 16 countries carried out a design project on using the resources of near-earth asteroids. The results of the project, whose full report is now available from ISU, are summarized. The student team included people in these fields: architecture, business and management, engineering, life sciences, physical sciences, policy and law, resources and manufacturing, and satellite applications. They designed a project for transporting equipment and personnel to a near-earth asteroid, setting up a mining base there, and hauling products back for use in cislunar space. In addition, they outlined the needed precursor steps, beginning with expansion of present ground-based programs for finding and characterizing near-earth asteroids and continuing with automated flight missions to candidate bodies. (To limit the summer project's scope the actual design of these flight-mission precursors was excluded.) The main conclusions were that asteroid mining may provide an important complement to the future use of lunar resources, with the potential to provide large amounts of water and carbonaceous materials for use off earth. However, the recovery of such materials from presently known asteroids did not show an economic gain under the study assumptions; therefore, asteroid mining cannot yet be considered a prospective business.

  11. Risky Behavior, Ecstasy, and Education

    Science.gov (United States)

    Callier, Heather H.

    2011-01-01

    Ecstasy is a risky behavior that continues to be a concern in the education system today. The review of the Ecstasy literature focused on the definition of risky behavior, prevalence, and other basis aspects of Ecstasy; discovering life events that are associated with Ecstasy use, the function of this behavior, interventions for substance abuse,…

  12. Asteroid Mining and Prospecting

    OpenAIRE

    Esty, Thomas

    2013-01-01

    There has been a recent increase in interest in the idea of mining asteroids, as seen from the founding of multiple companies who seek to make this science fiction idea science fact. We analyzed a number of prior papers on asteroids to make an estimate as to whether mining asteroids is within the realm of possibility. Existing information on asteroid number, composition, and orbit from past research was synthesized with a new analysis using binomial statistics of the number of probes that wou...

  13. Human factors in cybersecurity; examining the link between Internet addiction, impulsivity, attitudes towards cybersecurity, and risky cybersecurity behaviours.

    Science.gov (United States)

    Hadlington, Lee

    2017-07-01

    The present study explored the relationship between risky cybersecurity behaviours, attitudes towards cybersecurity in a business environment, Internet addiction, and impulsivity. 538 participants in part-time or full-time employment in the UK completed an online questionnaire, with responses from 515 being used in the data analysis. The survey included an attitude towards cybercrime and cybersecurity in business scale, a measure of impulsivity, Internet addiction and a 'risky' cybersecurity behaviours scale. The results demonstrated that Internet addiction was a significant predictor for risky cybersecurity behaviours. A positive attitude towards cybersecurity in business was negatively related to risky cybersecurity behaviours. Finally, the measure of impulsivity revealed that both attentional and motor impulsivity were both significant positive predictors of risky cybersecurity behaviours, with non-planning being a significant negative predictor. The results present a further step in understanding the individual differences that may govern good cybersecurity practices, highlighting the need to focus directly on more effective training and awareness mechanisms.

  14. Asteroid thermophysical modeling

    CERN Document Server

    Delbo, Marco; Emery, Joshua P; Rozitis, Ben; Capria, Maria Teresa

    2015-01-01

    The field of asteroid thermophysical modeling has experienced an extraordinary growth in the last ten years, as new thermal infrared data became available for hundreds of thousands of asteroids. The infrared emission of asteroids depends on the body's size, shape, albedo, thermal inertia, roughness and rotational properties. These parameters can therefore be derived by thermophysical modeling of infrared data. Thermophysical modeling led to asteroid size estimates that were confirmed at the few-percent level by later spacecraft visits. We discuss how instrumentation advances now allow mid-infrared interferometric observations as well as high-accuracy spectro-photometry, posing their own set of thermal-modeling challenges.We present major breakthroughs achieved in studies of the thermal inertia, a sensitive indicator for the nature of asteroids soils, allowing us, for instance, to determine the grain size of asteroidal regoliths. Thermal inertia also governs non-gravitational effects on asteroid orbits, requir...

  15. Divorce as risky behavior.

    Science.gov (United States)

    Light, Audrey; Ahn, Taehyun

    2010-11-01

    Given that divorce often represents a high-stakes income gamble, we ask how individual levels of risk tolerance affect the decision to divorce. We extend the orthodox divorce model by assuming that individuals are risk averse, that marriage is risky, and that divorce is even riskier. The model predicts that conditional on the expected gains to marriage and divorce, the probability of divorce increases with relative risk tolerance because risk averse individuals require compensation for the additional risk that is inherent in divorce. To implement the model empirically, we use data for first-married women and men from the 1979 National Longitudinal Survey of Youth to estimate a probit model of divorce in which a measure of risk tolerance is among the covariates. The estimates reveal that a 1-point increase in risk tolerance raises the predicted probability of divorce by 4.3% for a representative man and by 11.4% for a representative woman. These findings are consistent with the notion that divorce entails a greater income gamble for women than for men.

  16. Asteroid exploration and utilization

    Science.gov (United States)

    Radovich, Brian M.; Carlson, Alan E.; Date, Medha D.; Duarte, Manny G.; Erian, Neil F.; Gafka, George K.; Kappler, Peter H.; Patano, Scott J.; Perez, Martin; Ponce, Edgar

    1992-01-01

    The Earth is nearing depletion of its natural resources at a time when human beings are rapidly expanding the frontiers of space. The resources possessed by asteroids have enormous potential for aiding and enhancing human space exploration as well as life on Earth. Project STONER (Systematic Transfer of Near Earth Resources) is based on mining an asteroid and transporting raw materials back to Earth. The asteroid explorer/sample return mission is designed in the context of both scenarios and is the first phase of a long range plan for humans to utilize asteroid resources. Project STONER is divided into two parts: asteroid selection and explorer spacecraft design. The spacecraft design team is responsible for the selection and integration of the subsystems: GNC, communications, automation, propulsion, power, structures, thermal systems, scientific instruments, and mechanisms used on the surface to retrieve and store asteroid regolith. The sample return mission scenario consists of eight primary phases that are critical to the mission.

  17. Tracking a Very Near Earth Asteroid

    Science.gov (United States)

    Bruck, R.; Rashid, S.; Peppard, T.

    2013-09-01

    The potential effects of an asteroid passing within close proximity to the Earth were recently realized. During the February 16, 2013 event, Asteroid 2012 DA14 passed within an estimated 27,700 kilometers of the earth, well within the geosynchronous (GEO) orbital belt. This was the closest known approach of a planetoid of this size, in modern history. The GEO belt is a region that is filled with critical communications satellites which provide relays for essential government, business and private datum. On the day of the event, optical instruments at Detachment 3, 21OG, Maui GEODSS were able to open in marginal atmospheric conditions, locate and collect metric and raw video data on the asteroid as it passed a point of near heliocentric orbital propinquity to the Earth. Prior to the event, the Joint Space Operations Center (JSpOC) used propagated trajectory data from NASA's Near Earth Object Program Office at the Jet Propulsion Laboratory to assess potential collisions with man-made objects in Earth orbit. However, the ability to actively track this asteroid through the populated satellite belt not only allowed surveillance for possible late orbital perturbations of the asteroid, but, afforded the ability to monitor possible strikes on all other orbiting bodies of anthropogenic origin either not in orbital catalogs or not recently updated in those catalogs. Although programmed only for tracking satellites in geocentric orbits, GEODSS was able to compensate and maintain track on DA14, collecting one hundred and fifty four metric observations during the event.

  18. Applied Astronomy: Asteroid Prospecting

    Science.gov (United States)

    Elvis, M.

    2013-09-01

    In the age of asteroid mining the ability to find promising ore-bearing bodies will be valuable. This will give rise to a new discipline- "Applied Astronomy". Just as most geologists work in industry, not in academia, the same will be true of astronomers. Just how rare or common ore-rich asteroids are likely to be, and the skills needed to assay their value, are discussed here, with an emphasis on remote - telescopic - methods. Also considered are the resources needed to conduct extensive surveys of asteroids for prospecting purposes, and the cost and timescale involved. The longer-term need for applied astronomers is also covered.

  19. Near-Sun asteroids

    Science.gov (United States)

    Emel'yanenko, V. V.

    2017-01-01

    As follows from dynamical studies, in the course of evolution, most near-Earth objects reach orbits with small perihelion distances. Changes of the asteroids in the vicinity of the Sun should play a key role in forming the physical properties, size distribution, and dynamical features of the near-Earth objects. Only seven of the discovered asteroids are currently moving along orbits with perihelion distances q orbits farther from the Sun. In this study, we found asteroids that have been recently orbiting with perihelion distances q orbits for hundreds to tens of thousands of years. To carry out astrophysical observations of such objects is a high priority.

  20. Measuring risky adolescent cycling behaviour.

    Science.gov (United States)

    Feenstra, Hans; Ruiter, Robert A C; Schepers, Jan; Peters, Gjalt-Jorn; Kok, Gerjo

    2011-09-01

    Adolescents are at a greater risk of being involved in traffic accidents than most other age groups, even before they start driving cars. This article aims to determine the factor structure of a self-report questionnaire measuring adolescent risky cycling behaviour, the ACBQ (Adolescent Cycling Behaviour Questionnaire). The questionnaire's structure was based on the widely used Driver Behaviour Questionnaire (DBQ). A sample of secondary school students (N = 1749; age range: 13-18 years) filled out the questionnaire. Factor analysis revealed a three-factor structure underlying the questionnaire, which was confirmed on two equally large portions of the entire sample. These three underlying factors were identified as errors, common violations and exceptional violations. The ACBQ is a useful instrument for measuring adolescents' risky cycling behaviour.

  1. Space weathering of asteroids

    CERN Document Server

    Shestopalov, D I; Cloutis, E A

    2012-01-01

    Analysis of laboratory experiments simulating space weathering optical effects on atmosphereless planetary bodies reveals that the time needed to alter the spectrum of an ordinary chondrite meteorite to resemble the overall spectral shape and slope of an S-type asteroid is about ~ 0.1 Myr. The time required to reduce the visible albedo of samples to ~ 0.05 is ~ 1 Myr. Since both these timescales are much less than the average collisional lifetime of asteroids larger than several kilometers in size, numerous low-albedo asteroids having reddish spectra with subdued absorption bands should be observed instead of an S-type dominated population. It is not the case because asteroid surfaces cannot be considered as undisturbed, unlike laboratory samples. We have estimated the number of collisions occurring in the time of 105 yr between asteroids and projectiles of various sizes and show that impact-activated motions of regolith particles counteract the progress of optical maturation of asteroid surfaces. Continual r...

  2. The Asteroid Impact Mission

    Science.gov (United States)

    Carnelli, Ian; Galvez, Andres; Mellab, Karim

    2016-04-01

    The Asteroid Impact Mission (AIM) is a small and innovative mission of opportunity, currently under study at ESA, intending to demonstrate new technologies for future deep-space missions while addressing planetary defense objectives and performing for the first time detailed investigations of a binary asteroid system. It leverages on a unique opportunity provided by asteroid 65803 Didymos, set for an Earth close-encounter in October 2022, to achieve a fast mission return in only two years after launch in October/November 2020. AIM is also ESA's contribution to an international cooperation between ESA and NASA called Asteroid Impact Deflection Assessment (AIDA), consisting of two mission elements: the NASA Double Asteroid Redirection Test (DART) mission and the AIM rendezvous spacecraft. The primary goals of AIDA are to test our ability to perform a spacecraft impact on a near-Earth asteroid and to measure and characterize the deflection caused by the impact. The two mission components of AIDA, DART and AIM, are each independently valuable but when combined they provide a greatly increased scientific return. The DART hypervelocity impact on the secondary asteroid will alter the binary orbit period, which will also be measured by means of lightcurves observations from Earth-based telescopes. AIM instead will perform before and after detailed characterization shedding light on the dependence of the momentum transfer on the asteroid's bulk density, porosity, surface and internal properties. AIM will gather data describing the fragmentation and restructuring processes as well as the ejection of material, and relate them to parameters that can only be available from ground-based observations. Collisional events are of great importance in the formation and evolution of planetary systems, own Solar System and planetary rings. The AIDA scenario will provide a unique opportunity to observe a collision event directly in space, and simultaneously from ground-based optical and

  3. Asteroids - NeoWs API

    Data.gov (United States)

    National Aeronautics and Space Administration — NeoWs (Near Earth Object Web Service) is a RESTful web service for near earth Asteroid information. With NeoWs a user can: search for Asteroids based on their...

  4. 2015 Barcelona Asteroid Day

    CERN Document Server

    Gritsevich, Maria; Palme, Herbert

    2017-01-01

    This volume is a compilation of the research presented at the International Asteroid Day workshop which was celebrated at Barcelona on June 30th, 2015. The proceedings discuss the beginning of a new era in the study and exploration of the solar system’s minor bodies. International Asteroid Day commemorates the Tunguska event of June 30th, 1908. The workshop’s goal was to promote the importance of dealing proactively with impact hazards from space. Multidisciplinary experts contributed to this discussion by describing the nature of comets and asteroids along with their offspring, meteoroids. New missions to return material samples of asteroids back to Earth such as Osiris-REx and Hayabusa 2, as well as projects like AIM and DART which will test impact deflection techniques for Potentially Hazardous Asteroids encounters were also covered. The proceedings include both an outreach level to popularize impact hazards and a scientific character which covers the latest knowledge on these topics, as well as offeri...

  5. Riski- ja kriisiviestintä sosiaalisessa mediassa

    OpenAIRE

    Ruokamo, Katri; Ruonala, Minna

    2014-01-01

    Tämän opinnäytetyön aiheena on riski- ja kriisiviestintä sosiaalisessa mediassa. Työ on toiminnallinen opinnäytetyö ja sen tarkoituksena oli luoda ohjeistus sosiaalisen median riski- ja kriisiviestintään toimeksiantajayritykselle. Työn pääasiallisena tavoitteena oli selvittää riski- ja kriisiviestinnän oikeaoppisia toimintatapoja sosiaalisen median viestintään. Osatavoitteina olivat riskien kartoitus toimeksiantajalle sekä hyvän ja huonon riski- ja kriisiviestinnän erojen määrittely. Työssä k...

  6. Enteral Nutrition and Care of Risky Newborns

    Directory of Open Access Journals (Sweden)

    Ebru Kilicarslan Toruner

    2013-09-01

    Full Text Available Making appropriate and effective enteral feeding is decreasing the morbidity and mortality rates of risky newborns. Most important problems during enteral feeding in risky newborns are realizing the enteral feeding needs late, not following enteral feeding protocols and errors in medical practices (misconnections etc.. The aim of this review article is to describe the gastrointestinal development, nutrition requirements, enteral nutrition, feeding intolerance and care of risky newborns. Increasing the awareness of health care professionals about this topic is promoted the quality of care in risky newborns. [J Contemp Med 2013; 3(3.000: 227-233

  7. Learning to Avoid Risky Actions

    OpenAIRE

    Malfaz, María; Miguel A. Salichs

    2011-01-01

    When a reinforcement learning agent executes actions that can cause frequent damage to itself, it can learn, by using Q-learning, that these actions must not be executed again. However, there are other actions that do not cause damage frequently but only once in a while, for example, risky actions such as parachuting. These actions may imply punishment to the agent and, depending on its personality, it would be better to avoid them. Nevertheless, using the standard Q-learning algorithm, the a...

  8. Geography of the asteroid belt

    Science.gov (United States)

    Zellner, B. H.

    1978-01-01

    The CSM classification serves as the starting point on the geography of the asteroid belt. Raw data on asteroid types are corrected for observational biases (against dark objects, for instance) to derive the distribution of types throughout the belt. Recent work on family members indicates that dynamical families have a true physical relationship, presumably indicating common origin in the breakup of a parent asteroid.

  9. The Active Asteroids

    CERN Document Server

    Jewitt, Dave

    2011-01-01

    Some asteroids eject dust, unexpectedly producing transient, comet-like comae and tails. First ascribed to the sublimation of near-surface water ice, mass losing asteroids (also called "main-belt comets") can in fact be driven by a surprising diversity of mechanisms. In this paper, we consider eleven dynamical asteroids losing mass, in nine of which the ejected material is spatially resolved. We address mechanisms for producing mass loss including rotational instability, impact ejection, electrostatic repulsion, radiation pressure sweeping, dehydration stresses and thermal fracture, in addition to the sublimation of ice. In two objects (133P and 238P) the repetitive nature of the observed activity leaves ice sublimation as the only reasonable explanation while, in a third ((596) Scheila), a recent impact is the cause. Another impact may account for activity in P/2010 A2 but this tiny object can also be explained as having shed mass after reaching rotational instability. Mass loss from (3200) Phaethon is proba...

  10. The Asteroid Impact Mission (AIM): Studying the geophysics of small binaries, measuring asteroid deflection and studying impact physics

    Science.gov (United States)

    Kueppers, Michael; Michel, Patrick; AIM Team

    2016-10-01

    Binary asteroids and their formation mechanisms are of particular interest for understanding the evolution of the small bodies in the solar system. Also, hazards to Earth from impact of near-Earth asteroids and their mitigation have drawn considerable interest over the last decades.Those subjects are both addressed by ESA's Asteroid Impact mission, which is part of the Asteroid Impact & Deflection Assessment (AIDA) currently under study in collaboration between NASA and ESA. NASA's DART mission will impact a projectile into the minor component of the binary near-Earth asteroid (65803) Didymos in 2022. The basic idea is to demonstrate the effect of the impact on the orbital period of the secondary around the primary. ESA's AIM will monitor the Didymos system for several months around the DART impact time.AIM will be launched in aurumn 2020. It is foreseen to arrive at Didymos in April 2022. The mission takes advantage of a close approach of Didymos to Earth. The next opportunity would arise in 2040 only.AIM will stay near Didymos for approximately 6 months. Most of the time it will be placed on the illuminated side of the system, at distances of approximately 35 km and 10 km. AIM is expected to move away from Didymos for some time around the DART impact.The reference payload for AIM includes two visual imagers, a hyperspectral camera, a lidar, a thermal infrared imager, a monostatic high frequency radar, and a bistatic low frequency radar. In addition, AIM will deploy a small lander on the secondary asteroid, and two cubesats that will be used for additional, more risky investigations close to or on the surface of the asteroid.Major contributions from AIM are expected in the study of the geophysics of small asteroids (including for the first time, radar measurements of an interior structure), the formation of binary asteroids, the momentum enhancement factor from the DART impact (through measuring the mass and the change of orbit of the seondary), and impact physics

  11. Manuel's asteroid disruption technique.

    Science.gov (United States)

    John, Manuel; Ipe, Abraham; Jacob, Ivan

    2015-06-01

    A seventy-year-old male presented with dense asteroid hyalosis in both eyes. He had undergone cataract extraction in one eye 3 years ago, and the other eye had immature cataract. Both the autorefractor and dilated streak retinoscopy did not give readings and subjective visual improvement could not be achieved. Immediately following YAG posterior capsulotomy and anterior vitreous asteroid disruption, the vision improved to 20/20 with recordable auto refractor and streak retinoscopy values. Our initial experience indicates that the treatment is simple, safe and effective but needs controlled and prospective studies to confirm its long-term safety.

  12. Crowdsourcing Business Model Innovation

    DEFF Research Database (Denmark)

    Waldner, Florian; Poetz, Marion

    Successfully adapting existing business models or developing new ones significantly influences a firm?s ability to generate profits and develop competitive advantages. However, business model innovation is perceived as a complex, risky and uncertain process and its success strongly depends...... on whether or not firms are capable of understanding and addressing their customers? needs. This study explores how crowdsourcing-based search approaches can contribute to the process of business model innovation. Drawing on data from a crowdsourcing initiative designed to develop ideas for new business...... models in the podcast industry, we provide first exploratory insights into the value of crowdsourcing for innovating a firm?s business model, and discuss which characteristics of crowd-contributors increase the quantity and quality of the outcome....

  13. Asteroid science by Gaia

    Science.gov (United States)

    Muinonen, Karri; Cellino, Alberto; Dell Oro, Aldo; Tanga, Paolo; Delbo, Marco; Mignard, Francois; Thuillot, William; Berthier, Jerome; Carry, Benoit; Hestroffer, Daniel; Granvik, Mikael; Fedorets, Grigori

    2016-07-01

    Since the start of its regular observing program in summer 2014, the Gaia mission has carried out systematic photometric, spectrometric, and astrometric observations of asteroids. In total, the unique capabilities of Gaia allow for the collection of an extensive and homogeneous data set of some 350,000 asteroids down to the limiting magnitude of G = 20.7 mag. The Gaia performance remains excellent over the entire available brightness range. Starting from 2003, a working group of European asteroid scientists has explored the main capabilities of the mission, defining the expected scientific impact on Solar System science. These results have served as a basis for developing the Gaia data reduction pipeline, within the framework of the Data Processing and Analysis Consortium (DPAC). We describe the distribution of the existing and forecoming Gaia observations in space and time for different categories of objects. We illustrate the peculiar properties of each single observation, as these properties will affect the subsequent exploitation of the mission data. We will review the expected performances of Gaia, basically as a function of magnitude and proper motion of the sources. We will further focus on the areas that will benefit from complementary observational campaigns to improve the scientific return of the mission, and on the involvement of the planetary science community as a whole in the exploitation of the Gaia survey. We will thus describe the current and future opportunities for ground-based observers and forthcoming changes brought by Gaia in some observational approaches, such as stellar occultations by transneptunian objects and asteroids. We will show first results from the daily, short-term processing of Gaia data, all the way from the onboard data acquisition to the ground-based processing. We illustrate the tools developed to compute predictions of asteroid observations, we discuss the procedures implemented by the daily processing, and we illustrate

  14. Asteroid Control and Resource Utilization

    Science.gov (United States)

    Paterson, G.; Radice, G.; Sanchez, J.-P.

    Asteroids are materials rich small solar system bodies which are prime candidates for rendezvous and mining. Up until now much attention has been focused on methods of destroying or deflecting potentially hazardous asteroids from colliding with the Earth. Recently however the concept of asteroid capture has been suggested whereby the asteroid is returned to an orbit close to the Earth before mining can begin. This paper aims to provide a comprehensive introduction to the field for new researchers and to put forward a number of novel strategies for asteroid control.

  15. NASA's Asteroid Redirect Mission (ARM)

    Science.gov (United States)

    Abell, P. A.; Mazanek, D. D.; Reeves, D. M.; Chodas, P. W.; Gates, M. M.; Johnson, L. N.; Ticker, R. L.

    2017-01-01

    Mission Description and Objectives: NASA's Asteroid Redirect Mission (ARM) consists of two mission segments: 1) the Asteroid Redirect Robotic Mission (ARRM), a robotic mission to visit a large (greater than approximately 100 meters diameter) near-Earth asteroid (NEA), collect a multi-ton boulder from its surface along with regolith samples, and return the asteroidal material to a stable orbit around the Moon; and 2) the Asteroid Redirect Crewed Mission (ARCM), in which astronauts will explore and investigate the boulder and return to Earth with samples. The ARRM is currently planned to launch at the end of 2021 and the ARCM is scheduled for late 2026.

  16. Risky traffic behaviour among young adolescents.

    NARCIS (Netherlands)

    2012-01-01

    Adolescence is the period between childhood and adulthood. Compared with older adolescents (18-24 years old), young adolescents (10-17 years old) exhibit more risky behaviour. Because of their physical and mental development, young adolescents are attracted to risky challenges, they are more

  17. Risky traffic behaviour among young adolescents.

    NARCIS (Netherlands)

    2012-01-01

    Adolescence is the period between childhood and adulthood. Compared with older adolescents (18-24 years old), young adolescents (10-17 years old) exhibit more risky behaviour. Because of their physical and mental development, young adolescents are attracted to risky challenges, they are more suscep

  18. Threat Mitigation: The Asteroid Tugboat

    CERN Document Server

    Schweickart, R; Durda, D; Hut, P; Chapman, Clark; Durda, Dan; Hut, Piet; Schweickart, Russell

    2006-01-01

    The Asteroid Tugboat (AT) is a fully controlled asteroid deflection concept using a robotic spacecraft powered by a high efficiency, electric propulsion system (ion or plasma) which docks with and attaches to the asteroid, conducts preliminary operations, and then thrusts continuously parallel to the asteroid velocity vector until the desired velocity change is achieved. Based on early warning, provided by ground tracking and orbit prediction, it would be deployed a decade or more prior to a potential impact. On completion of the initial rendezvous with the near-Earth object (NEO) the AT would first reduce the uncertainty in the orbit of the asteroid via Earth tracking of its radio transponder while it is station keeping with the asteroid. If on analysis of tracking data a deflection is required the AT would execute a reconnaissance phase collecting and processing information about the physical characteristics of the asteroid to support subsequent operations. The AT would then dock at the appropriate pole (i....

  19. The Asteroid Frontier

    Science.gov (United States)

    Mcfadden, Lucyann A.

    2012-01-01

    There are many ways of studying the Asteroid Frontier as a scientist. In my career, I have used large telescopes atop a 14,000 ft mountain top observatory in Hawaii, used the Hubble Space Telescope in orbit around the Earth, traveled to Antarctica to collect meteorites sitting on the ice waiting for them to be recovered by scientists for scientific investigation, walked the desert with 50 students from University of Khartoum searching for fragments of an asteroid that collided with earth, exploded in the upper atmosphere and rained fragments on the desert floor. Most recently, I have looked at one of the largest Main Belt Asteroids named (4) Vesta through the eyes of a robotic spacecraft named Dawn, exploring the asteroid frontier. I will share my adventures, place the thrill of scientific exploration through NASA's solar system exploration program in context and provide opportunities for students to engage in NASA's exciting missions to expand scientific understanding of Earth and the Universe in which we live

  20. Asteroids, meteorites, and comets

    CERN Document Server

    Elkins-Tanton, Linda T

    2010-01-01

    Asteroids, Comets, and Meteorites provides students, researchers, and general readers with the most up-to-date information on this fascinating field. From the days of the dinosaurs to our modern environment, this book explores all aspects of these cosmic invaders.

  1. Asteroid Kinetic Impactor Missions

    Science.gov (United States)

    Chesley, Steven

    2015-08-01

    Asteroid impact missions can be carried out as a relatively low-cost add-ons to most asteroid rendezvous missions and such impact experiments have tremendous potential, both scientifically and in the arena of planetary defense.The science returns from an impactor demonstration begin with the documentation of the global effects of the impact, such as changes in orbit and rotation state, the creation and dissipation of an ejecta plume and debris disk, and morphological changes across the body due to the transmission of seismic waves, which might induce landslides and toppling of boulders, etc. At a local level, an inspection of the impact crater and ejecta blanket reveals critical material strength information, as well as spectral differences between the surface and subsurface material.From the planetary defense perspective, an impact demonstration will prove humankind’s capacity to alter the orbit of a potentially threatening asteroid. This technological leap comes in two parts. First, terminal guidance systems that can deliver an impactor with small errors relative to the ~100-200 meter size of a likely impactor have yet to be demonstrated in a deep space environment. Second, the response of an asteroid to such an impact is only understood theoretically due to the potentially significant dependence on the momentum carried by escaping ejecta, which would tend to enhance the deflection by tens of percent and perhaps as much as a factor of a few. A lack of validated understanding of momentum enhancement is a significant obstacle in properly sizing a real-world impactor deflection mission.This presentation will describe the drivers for asteroid impact demonstrations and cover the range of such concepts, starting with ESA’s pioneering Don Quijote mission concept and leading to a brief description of concepts under study at the present time, including the OSIRIS-REx/ISIS, BASiX/KIX and AIM/DART (AIDA) concepts.

  2. Reducing risky driver behaviour through the implementation of a driver risk management system

    Directory of Open Access Journals (Sweden)

    Rose Luke

    2014-03-01

    Full Text Available South Africa has one of the highest incidences of road accidents in the world. Most accidents are avoidable and are caused by driver behaviour and errors. The purpose of this article was to identify the riskiest driver behaviours in commercial fleets in South Africa, to determine the business impact of such behaviour, to establish a framework for the management of risky driver behaviour and to test the framework by applying a leading commercial driver behaviour management system as a case study. The case study comprised three South African commercial fleets. Using data from these fleets, critical incident triangles were used to determine the ratio data of risky driver behaviour to near-collisions and collisions. Based on managing the riskiest driver behaviours as causes of more serious incidents and accidents, the results indicated that through the implementation of an effective driver risk management system, risky incidents were significantly reduced.

  3. Risky driving and lifestyles in adolescence.

    Science.gov (United States)

    Bina, Manuela; Graziano, Federica; Bonino, Silvia

    2006-05-01

    Several studies have shown that risky driving is especially prevalent among young drivers and recent research has pointed out that driving in adolescence should be investigated in the more general context of adolescent development. The first aim of this contribution was to analyze involvement in risky driving in a normative sample of 645 Italian adolescents, boys and girls, aged 14-17, through a self-report questionnaire. A second aim was to evaluate the association between risky driving and lifestyle, defined as involvement in other health risk behaviors and leisure activities. The main results showed that many adolescents drove cars and motorcycles without the required driving license and the most frequent offences were speeding and failure to maintain a safe braking distance. Gender and age differences were also investigated. Results concerning the association between risky driving and lifestyle showed that risky driving was not an isolated behavior. Boys who displayed risky driving practices were more likely to adopt a lifestyle characterized by high involvement in antisocial behaviors, tobacco smoking, comfort eating and time spent in non-organized activities with friends. Girls involved in risky driving were more likely to be involved in other risk-taking behaviors, antisocial behaviors and drug use.

  4. Capture of Asteroids and Transport of Asteroid Materials to Earth

    Science.gov (United States)

    Chiu, Hong-Yee; no Team

    2014-01-01

    Recently there has been much discussion on the capture of asteroids or mining the asteroids. While the technology might be years away, in this paper we will discuss an energy efficient method to transport either a small asteroid or materials gathered from asteroids to the Earth. In particular, I will concentrate on a large and nearby asteroid, 8 Flora in the Flora Family. Generally, asteroids are located between 2 to 3 AU (astronomical unit) from the Earth, and in transporting materials from asteroids to the Earth, an energy equivalent of the gravitational potential energy difference between the Earth and the asteroids to the Sun. This amount of potential energy is a sizable fraction of the orbital kinetic energy of the Earth around the Sun. This amount of energy is considerable. In this paper I propose to use the planet Mars as a medium to remove much of the gravitational energy difference. In the case of the asteroid 8 Flora, it is only necessary to decelerate the asteroid mate- rials by a small decrement, of the order of 3 km/sec. This decrement could even be achieved (pending on the availability of technology) by mechanical devices such as catapults on 8 Flora. It is also proposed to separate a pair of contact asteroid binaries by using impulse propulsion, and to propel one component of the separated asteroids to pass by Mars to be decelerated to reach the Earth orbit and captured by the Earth or the Moon. The plausibility of this ambitious project will be discussed. The author is NASA-GSFC Astrophysicist, Retired.

  5. EURONEAR - Data Mining of Asteroids and Near Earth Asteroids

    OpenAIRE

    Vaduvescu, O.; Curelaru, L.; Birlan, M.; Bocsa, G.; Serbanescu, L.; Tudorica, A.; Berthier, J.

    2009-01-01

    Besides new observations, mining old photographic plates and CCD image archives represents an opportunity to recover and secure newly discovered asteroids, also to improve the orbits of Near Earth Asteroids (NEAs), Potentially Hazardous Asteroids (PHAs) and Virtual Impactors (VIs). These are the main research aims of the EURONEAR network. As stated by the IAU, the vast collection of image archives stored worldwide is still insufficiently explored, and could be mined for known NEAs and other a...

  6. Active Asteroids: Main-Belt Comets and Disrupted Asteroids

    CERN Document Server

    Hsieh, Henry H

    2015-01-01

    The study of active asteroids has attracted a great deal of interest in recent years since the recognition of main-belt comets (which orbit in the main asteroid belt, but exhibit comet-like activity due to the sublimation of volatile ices) as a new class of comets in 2006, and the discovery of the first disrupted asteroids (which, unlike MBCs, exhibit comet-like activity due to a physical disruption such as an impact or rotational destabilization, not sublimation) in 2010. In this paper, I will briefly discuss key areas of interest in the study of active asteroids.

  7. Asteroid family ages

    CERN Document Server

    Spoto, Federica; Knezevic, Zoran

    2015-01-01

    A new family classification, based on a catalog of proper elements with $\\sim 384,000$ numbered asteroids and on new methods is available. For the $45$ dynamical families with $>250$ members identified in this classification, we present an attempt to obtain statistically significant ages: we succeeded in computing ages for $37$ collisional families. We used a rigorous method, including a least squares fit of the two sides of a V-shape plot in the proper semimajor axis, inverse diameter plane to determine the corresponding slopes, an advanced error model for the uncertainties of asteroid diameters, an iterative outlier rejection scheme and quality control. The best available Yarkovsky measurement was used to estimate a calibration of the Yarkovsky effect for each family. The results are presented separately for the families originated in fragmentation or cratering events, for the young, compact families and for the truncated, one-sided families. For all the computed ages the corresponding uncertainties are pro...

  8. Asteroid Impact Monitoring

    Science.gov (United States)

    Milani, A.

    2006-06-01

    Some asteroids and comets with Earth-crossing orbit may impact our planet, thus we need to be able to identify the cases which could have a dangerous close approach within a century. This must be done as soon as such an asteroid is discovered, allowing for follow up observations which might contradict the impact possibility, and in the worst case to organize mitigation, possibly including deflection. The mathematical problem of predicting possible impacts, even with very low probabilities, has been solved by our group in the last few years. This paper presents the basic theory of these impact prediction, and discusses how they are practically used in the impact monitoring systems now operational, in particular the CLOMON2 robot of the Universities of Pisa and Valladolid.

  9. Asteroid impact monitoring

    Directory of Open Access Journals (Sweden)

    Milani A.

    2006-01-01

    Full Text Available Some asteroids and comets with Earth-crossing orbit may impact our planet, thus we need to be able to identify the cases which could have a dangerous close approach within a century. This must be done as soon as such an asteroid is discovered, allowing for follow up observations which might contradict the impact possibility, and in the worst case to organize mitigation, possibly including deflection. The mathematical problem of predicting possible impacts, even with very low probabilities, has been solved by our group in the last few years. This paper presents the basic theory of these impact prediction, and discusses how they are practically used in the impact monitoring systems now operational, in particular the CLOMON2 robot of the Universities of Pisa and Valladolid.

  10. Asteroid Surface Geophysics

    CERN Document Server

    Murdoch, Naomi; Schwartz, Stephen R; Miyamoto, Hideaki

    2015-01-01

    The regolith-covered surfaces of asteroids preserve records of geophysical processes that have occurred both at their surfaces and sometimes also in their interiors. As a result of the unique micro-gravity environment that these bodies posses, a complex and varied geophysics has given birth to fascinating features that we are just now beginning to understand. The processes that formed such features were first hypothesised through detailed spacecraft observations and have been further studied using theoretical, numerical and experimental methods that often combine several scientific disciplines. These multiple approaches are now merging towards a further understanding of the geophysical states of the surfaces of asteroids. In this chapter we provide a concise summary of what the scientific community has learned so far about the surfaces of these small planetary bodies and the processes that have shaped them. We also discuss the state of the art in terms of experimental techniques and numerical simulations that...

  11. Multiple origins of asteroid pairs

    CERN Document Server

    Jacobson, Seth A

    2015-01-01

    Rotationally fissioned asteroids produce unbound daughter asteroids that have very similar heliocentric orbits. Backward integration of their current heliocentric orbits provides an age of closest proximity that can be used to date the rotational fission event. Most asteroid pairs follow a predicted theoretical relationship between the primary spin period and the mass ratio of the two pair members that is a direct consequence of the YORP-induced rotational fission hypothesis. If the progenitor asteroid has strength, asteroid pairs may have high mass ratios with possibly fast rotating primaries. However, secondary fission leaves the originally predicted trend unaltered. We also describe the characteristics of pair members produced by four alternative routes from a rotational fission event to an asteroid pair. Unlike direct formation from the event itself, the age of closest proximity of these pairs cannot generally be used to date the rotational fission event since considerable time may have passed.

  12. Crowdsourcing business model innovation

    DEFF Research Database (Denmark)

    Waldner, Florian; Poetz, Marion Kristin; Bogers, Marcel

    2016-01-01

    Successfully adapting existing business models or developing new ones significantly influences a firm’s ability to generate profits and develop competitive advantages. However, business model innovation is perceived as a complex, risky and uncertain process and its success strongly depends...... the perspective of classic strategy making literature, suggest that, at least under certain conditions, crowdsourcing might constitute a promising method to alleviate the process of successful business model innovation....... on whether or not the firm is capable of understanding and addressing their customers’ needs. We conduct a quantitative exploratory case study to investigate how crowdsourcing-based search approaches among user communities can contribute to developing business model innovation. Drawing on data from...

  13. Silicates in Alien Asteroids

    Science.gov (United States)

    2009-01-01

    This plot of data from NASA's Spitzer Space Telescopes shows that asteroid dust around a dead 'white dwarf' star contains silicates a common mineral on Earth. The data were taken primarily by Spitzer's infrared spectrograph, an instrument that breaks light apart into its basic constituents. The yellow dots show averaged data from the spectrograph, while the orange triangles show older data from Spitzer's infrared array camera. The white dwarf is called GD 40.

  14. The Rafita asteroid family

    Science.gov (United States)

    Aljbaae, S.; Carruba, V.; Masiero, J. R.; Domingos, R. C.; Huaman, M.

    2017-01-01

    The Rafita asteroid family is an S-type group located in the middle main belt, on the right side of the 3J:-1A mean-motion resonance. The proximity of this resonance to the family left side in semi-major axis caused many former family members to be lost. As a consequence, the family shape in the (a, 1/D) domain is quite asymmetrical, with a preponderance of objects on the right side of the distribution. The Rafita family is also characterized by a leptokurtic distribution in inclination, which allows the use of methods of family age estimation recently introduced for other leptokurtic families such as Astrid, Hansa, Gallia, and Barcelona. In this work we propose a new method based on the behavior of an asymmetry coefficient function of the distribution in the (a, 1/D) plane to date incomplete asteroid families such as Rafita. By monitoring the time behavior of this coefficient for asteroids simulating the initial conditions at the time of the family formation, we were able to estimate that the Rafita family should have an age of 490 ± 200 Myr, in good agreement with results from independent methods such as Monte Carlo simulations of Yarkovsky and Yorp dynamical induced evolution and the time behaviour of the kurtosis of the sin (i) distribution. Asteroids from the Rafita family can reach orbits similar to 8% of the currently known near Earth objects. ≃1% of the simulated objects are present in NEO-space during the final 10 Myr of the simulation, and thus would be comparable to objects in the present-day NEO population.

  15. Silicates in Alien Asteroids

    Science.gov (United States)

    2009-01-01

    This plot of data from NASA's Spitzer Space Telescopes shows that asteroid dust around a dead 'white dwarf' star contains silicates a common mineral on Earth. The data were taken primarily by Spitzer's infrared spectrograph, an instrument that breaks light apart into its basic constituents. The yellow dots show averaged data from the spectrograph, while the orange triangles show older data from Spitzer's infrared array camera. The white dwarf is called GD 40.

  16. Modeling of Fragmentation of Asteroids

    Science.gov (United States)

    Agrawal, Parul; Prabhu, Dinesh K.; Carlozzi, Alexander; Hart, Kenneth; Bryson, Katie; Sears, Derek

    2015-01-01

    The objective of this study is to understand fragmentation and fracture of a given asteroid and mechanisms of break-up. The focus of the present work is to develop modeling techniques for stony asteroids in 10m-100m range to answer two questions: 1) What is the role of material makeup of an asteroid in the stress distribution? 2)How is stress distribution altered in the presence of pre-existing defects?

  17. Comet or Asteroid?

    Science.gov (United States)

    1997-11-01

    When is a minor object in the solar system a comet? And when is it an asteroid? Until recently, there was little doubt. Any object that was found to display a tail or appeared diffuse was a comet of ice and dust grains, and any that didn't, was an asteroid of solid rock. Moreover, comets normally move in rather elongated orbits, while most asteroids follow near-circular orbits close to the main plane of the solar system in which the major planets move. However, astronomers have recently discovered some `intermediate' objects which seem to possess properties that are typical for both categories. For instance, a strange object (P/1996 N2 - Elst-Pizarro) was found last year at ESO ( ESO Press Photo 36/96 ) which showed a cometary tail, while moving in a typical asteroidal orbit. At about the same time, American scientists found another (1996 PW) that moved in a very elongated comet-type orbit but was completely devoid of a tail. Now, a group of European scientists, by means of observations carried out at the ESO La Silla observatory, have found yet another object that at first appeared to be one more comet/asteroid example. However, continued and more detailed observations aimed at revealing its true nature have shown that it is most probably a comet . Consequently, it has received the provisional cometary designation P/1997 T3 . The Uppsala-DLR Trojan Survey Some time ago, Claes-Ingvar Lagerkvist (Astronomical Observatory, Uppsala, Sweden), in collaboration with Gerhard Hahn, Stefano Mottola, Magnus Lundström and Uri Carsenty (DLR, Institute of Planetary Exploration, Berlin, Germany), started to study the distribution of asteroids near Jupiter. They were particularly interested in those that move in orbits similar to that of Jupiter and which are located `ahead' of Jupiter in the so-called `Jovian L4 Lagrangian point'. Together with those `behind' Jupiter, these asteroids have been given the names of Greek and Trojan Heroes who participated in the famous Trojan war

  18. Implicit attitudes towards risky and safe driving

    DEFF Research Database (Denmark)

    Martinussen, Laila Marianne; Sømhovd, Mikael Julius; Møller, Mette;

    ; further, self-reports of the intention to drive safely (or not) are socially sensitive. Therefore, we examined automatic preferences towards safe and risky driving with a Go/No-go Association Task (GNAT). The results suggest that (1) implicit attitudes towards driving behavior can be measured reliably...... with the GNAT; (2) implicit attitudes towards safe driving versus towards risky driving may be separable constructs. We propose that research on driving behavior may benefit from routinely including measures of implicit cognition. A practical advantage is a lesser susceptibility to social desirability biases......, compared to self-report methods. Pending replication in future research, the apparent dissociation between implicit attitudes towards safe versus risky driving that we observed may contribute to a greater theoretical understanding of the causes of unsafe and risky driving behavior....

  19. Risky Business: Reducing Moral Hazard in Airlift Operations

    Science.gov (United States)

    2012-06-01

    twenty 120mm mortars , and an unconfirmed number of 82mm mortars , several Katyusha rocket launchers, and at least thirty-six 37mm anti-aircraft guns.24...the French had brought in 10 US-supplied M24 Chaffee tanks, twenty-four 105mm howitzers, four 155mm howitzers, and a heavy mortar company, all by air...name “to invoke an image of cascading bombs and shells.”8 Having recognized the buildup of NVA forces and selected a means of defense, planning for

  20. Risky Business: Exploring Adolescent Risk-Taking Behavior

    Science.gov (United States)

    Wyatt, Tammy Jordan; Peterson, Fred L.

    2005-01-01

    Ongoing behavioral research has documented the growing prevalence of adolescent health risk behaviors, such as tobacco use, sexual activity, alcohol and other substance use, nutritional behavior, physical inactivity, and intentional injury. Newer youth risk behaviors, such as pathological gambling, are emerging as threats to public health. Risk,…

  1. The risky business of educational choice in the meritocratic society

    DEFF Research Database (Denmark)

    Karlson, Kristian Bernt; Holm, Anders

    2015-01-01

    families differ in the extent by which they have the resources required for navigating the risks associated with making these choices, educational inequality may persist in spite of educational expansion. Analyzing class differences in adolescents’ educational expectations for two Danish cohorts born...

  2. Risky business. Organizations tackle infection control during construction.

    Science.gov (United States)

    Burmhal, Beth

    2003-06-01

    Construction projects, no matter how minor, can be dangerous for patients who are especially sensitive to infection. Guidelines from three prominent organizations are finally helping hospitals understand how to prevent infections during those projects.

  3. Risky Business: An Ecological Analysis of Intimate Partner Violence Disclosure

    Science.gov (United States)

    Alaggia, Ramona; Regehr, Cheryl; Jenney, Angelique

    2012-01-01

    Objective: A multistage, mixed-methods study using grounded theory with descriptive data was conducted to examine factors in disclosure of intimate partner violence (IPV). Method: In-depth interviews with individuals and focus groups were undertaken to collect data from 98 IPV survivors and service providers to identify influential factors.…

  4. Risky Business: Whose "Right Thing" Are We Talking about?

    Science.gov (United States)

    Monseau, Virginia R.

    2008-01-01

    Questioning the dichotomy of right and wrong, Virginia R. Monseau explores the tensions that arise from choices teachers make when trying to "do the right thing." From warning teachers about difficult students to presenting sensitive materials that challenge student belief systems, Monseau advises educators to pay close attention,…

  5. Risky Business: Reducing Moral Hazard in Airlift Operations

    Science.gov (United States)

    2015-01-01

    be an overstatement, JPADS does employ a computer that uses a global positioning system signal to calculate the position of the cargo in the air and...asserting the im- portance of flexibility among LOCs, it seems to counter this somewhat by allowing for a sole source of sustainment without a balanced

  6. Risky Business: Mental Illness, Disclosure and the TAFE Student

    Science.gov (United States)

    Venville, Annie

    2010-01-01

    This paper meets at the crossroads of personal experience and public policy. The personal is the experience of learning as described by five TAFE students with a mental illness. The public policy context is the increased political pressure on Australia's major vocational training providers to increase workforce participation of people with mental…

  7. Risky Business: The Market for Unprotected Commercial Sex.

    Science.gov (United States)

    Gertler, Paul; Shah, Manisha; Bertozzi, Stefano M.

    2005-01-01

    While condoms are an effective defense against the transmission of HIV, large numbers of sex workers are not using them. We argue that some sex workers are willing to take the risk because clients are willing to pay more to avoid using condoms. Using data from Mexico, we estimate that sex workers received a 23 percent premium for unprotected sex.…

  8. Risky business: challenges and successes in military radiation risk communication.

    Science.gov (United States)

    Melanson, Mark A; Geckle, Lori S; Davidson, Bethney A

    2012-01-01

    Given the general public's overall lack of knowledge about radiation and their heightened fear of its harmful effects, effective communication of radiation risks is often difficult. This is especially true when it comes to communicating the radiation risks stemming from military operations. Part of this difficulty stems from a lingering distrust of the military that harkens back to the controversy surrounding Veteran exposures to Agent Orange during the Vietnam War along with the often classified nature of many military operations. Additionally, there are unique military exposure scenarios, such as the use of nuclear weapons and combat use of depleted uranium as antiarmor munitions that are not found in the civilian sector. Also, the large, diverse nature of the military makes consistent risk communication across the vast and widespread organization very difficult. This manuscript highlights and discusses both the common and the distinctive challenges of effectively communicating military radiation risks, to include communicating through the media. The paper also introduces the Army's Health Risk Communication Program and its role in assisting in effective risk communication efforts. The authors draw on their extensive collective experience to share 3 risk communication success stories that were accomplished through the innovative use of a matrixed, team approach that combines both health physics and risk communication expertise.

  9. Risky business: effectiveness of state market-based health programs.

    Science.gov (United States)

    Stream, Christopher; Myers, Nathan

    2010-02-01

    Since the 1990s, state governments have been leaders of health care reform. Today, approximately 47 million people are without health insurance. As health care costs and uninsurance levels continue to rise, states are pursuing a variety of government- and market-based strategies to address this growing social problem. Health care research has indicated that state-based programs have proven to be successful in extending access to coverage. However, the question remains as to whether the market-based programs have had a positive impact on state health care. Advocates for market-based state health programs argue that the reforms benefit the greater good because they serve an economic development function by improving the economic productivity and overall health of state citizens. Whether market-based policies are accomplishing these goals is a matter of debate. This study examines the effects of the various market-based state policies. The evidence generated by this research sheds light on the societal effectiveness of market-based health care strategies used by state governments. The results of our analysis indicate that programs enacted by states to promote increased access to medical care have developmental effects beyond the client population directly served.

  10. Risky business: failure to prevent and failure to communicate.

    Science.gov (United States)

    Moore, Dorothy L; Ste-Marie, Micheline

    2009-01-01

    Healthcare-associated infections (HAIs), important threats to patient safety, are considered differently from other adverse events. Gardam and his colleagues discuss several reasons for this and outline approaches that may bring about changes in attitudes and enhance HAI prevention. We comment on the potential preventability of HAIs, the need for improved communication strategies and the different vision of the role of infection control personnel suggested by Gardam et al. Recent developments in infection control structure and management and patient safety in Quebec are summarized.

  11. "Risky Business": The College Transition, Loneliness, and Alcohol Consumption

    Science.gov (United States)

    McBroom, Elizabeth M.; Fife, Eric M.; Nelson, C. Leigh

    2008-01-01

    A total of 296 students at a large southeastern university completed a series of measures designed to assess the connection between loneliness and alcohol use in the first college year. Results showed a somewhat surprising negative relationship between loneliness and alcohol consumption: As loneliness decreased, consumption increased. The…

  12. Risky business: sexual and asexual reproduction in variable environments.

    Science.gov (United States)

    Robson, A J; Bergstrom, C T; Pritchard, J K

    1999-04-21

    Patterns of reproductive uncertainty can have an important influence on population dynamics. There is a crucial distinction between what we describe here as aggregate uncertainty (in which reproductive output in each generation is correlated among the individuals in a population) and idiosyncratic risk (in which reproductive output is independent across individuals). All else being equal, populations experiencing idiosyncratic risk enjoy a higher asymptotic growth rate than do those experiencing aggregate uncertainty. Therefore individuals in populations of the former type will have a competitive advantage over individuals in populations of the latter type. Applying this distinction to models of randomly fluctuating environments, we point out that genetic variation among offspring can serve to reduce aggregate uncertainty, transforming it into a more idiosyncratic form of risk. We show that this transformation underlies the dynamics observed in several previous models of the role of outcrossing in the evolution of sex.

  13. Risky Business: Understanding Student Intellectual Risk Taking in Management Education

    Science.gov (United States)

    Dachner, Alison M.; Miguel, Rosanna F.; Patena, Rachel A.

    2017-01-01

    The demands of today's ever-changing work environment often require that employees engage in intellectual risk taking (IRT) by being resourceful, trying new things, and asking questions even at the risk of making a mistake or feeling inadequate. This research seeks to identify variables that increase student IRT. Controlling for individual…

  14. Risky Business: Development, Communication and Use of Hydroclimatic Forecasts

    Science.gov (United States)

    Lall, U.

    2012-12-01

    Inter-seasonal and longer hydroclimatic forecasts have been made increasingly in the last two decades following the increase in ENSO activity since the early 1980s and the success in seasonal ENSO forecasting. Yet, the number of examples of systematic use of these forecasts and their incorporation into water systems operation continue to be few. This may be due in part to the limited skill in such forecasts over much of the world, but is also likely due to the limited evolution of methods and opportunities to "safely" use uncertain forecasts. There has been a trend to rely more on "physically based" rather than "physically informed" empirical forecasts, and this may in part explain the limited success in developing usable products in more locations. Given the limited skill, forecasters have tended to "dumb" down their forecasts - either formally or subjectively shrinking the forecasts towards climatology, or reducing them to tercile forecasts that serve to obscure the potential information in the forecast. Consequently, the potential utility of such forecasts for decision making is compromised. Water system operating rules are often designed to be robust in the face of historical climate variability, and consequently are adapted to the potential conditions that a forecast seeks to inform. In such situations, there is understandable reluctance by managers to use the forecasts as presented, except in special cases where an alternate course of action is pragmatically appealing in any case. In this talk, I review opportunities to present targeted forecasts for use with decision systems that directly address climate risk and the risk induced by unbiased yet uncertain forecasts, focusing especially on extreme events and water allocation in a competitive environment. Examples from Brazil and India covering surface and ground water conjunctive use strategies that could potentially be insured and lead to improvements over the traditional system operation and resource allocation are provided.

  15. Child Maltreatment and Risky Sexual Behavior.

    Science.gov (United States)

    Thompson, Richard; Lewis, Terri; Neilson, Elizabeth C; English, Diana J; Litrownik, Alan J; Margolis, Benyamin; Proctor, Laura; Dubowitz, Howard

    2017-02-01

    Risky sexual behavior is a serious public health problem. Child sexual abuse is an established risk factor, but other forms of maltreatment appear to elevate risky behavior. The mechanisms by which child maltreatment influence risk are not well understood. This study used data from 859 high-risk youth, followed through age 18. Official reports of each form of maltreatment were coded. At age 16, potential mediators (trauma symptoms and substance use) were assessed. At age 18, risky sexual behavior (more than four partners, unprotected sex, unassertiveness in sexual refusal) was assessed. Neglect significantly predicted unprotected sex. Substance use predicted unprotected sex and four or more partners but did not mediate the effects of maltreatment. Trauma symptoms predicted unprotected sex and mediated effects of emotional maltreatment on unprotected sex and on assertiveness in sexual refusal and the effects of sexual abuse on unprotected sex. Both neglect and emotional maltreatment emerged as important factors in risky sexual behavior. Trauma symptoms appear to be an important pathway by which maltreatment confers risk for risky sexual behavior. Interventions to reduce risky sexual behavior should include assessment and treatment for trauma symptoms and for history of child maltreatment in all its forms.

  16. AIDA: Asteroid Impact & Deflection Assessment

    Science.gov (United States)

    Cheng, A. F.; Galvez, A.; Carnelli, I.; Michel, P.; Rivkin, A.; Reed, C.

    2012-12-01

    To protect the Earth from a hazardous asteroid impact, various mitigation methods have been proposed, including deflection of the asteroid by a spacecraft impact. AIDA, consisting of two mission elements, the Double Asteroid Redirection Test (DART) and the Asteroid Impact Monitoring (AIM) mission, is a demonstration of asteroid deflection. To date, there has been no such demonstration, and there is major uncertainty in the result of a spacecraft impact onto an asteroid, that is, the amount of deflection produced by a given momentum input from the impact. This uncertainty is in part due to unknown physical properties of the asteroid surface, such as porosity and strength, and in part due to poorly understood impact physics such that the momentum carried off by ejecta is highly uncertain. A first mission to demonstrate asteroid deflection would not only be a major step towards gaining the capability to mitigate an asteroid hazard, but in addition it would return unique information on an asteroid's strength, other surface properties, and internal structure. This information return would be highly relevant to future human exploration of asteroids. We report initial results of the AIDA joint mission concept study undertaken by the Johns Hopkins Applied Physics Laboratory and ESA with support from NASA centers including Goddard, Johnson and Jet Propulsion Laboratory. For AIDA, the DART spacecraft impactor study is coordinated with an ESA study of the AIM mission, which would rendezvous with the same asteroid to measure effects of the impact. Unlike the previous Don Quijote mission study performed by ESA in 2005-2007, DART envisions an impactor spacecraft to intercept the secondary member of a binary near-Earth asteroid. DART includes ground-based observations to measure the deflection independently of the rendezvous spacecraft observations from AIM, which also measures deflection and provides detailed characterization of the target asteroid. The joint mission AIDA

  17. EURONEAR - Data Mining of Asteroids and Near Earth Asteroids

    CERN Document Server

    Vaduvescu, O; Birlan, M; Bocsa, G; Serbanescu, L; Tudorica, A; Berthier, J

    2009-01-01

    Besides new observations, mining old photographic plates and CCD image archives represents an opportunity to recover and secure newly discovered asteroids, also to improve the orbits of Near Earth Asteroids (NEAs), Potentially Hazardous Asteroids (PHAs) and Virtual Impactors (VIs). These are the main research aims of the EURONEAR network. As stated by the IAU, the vast collection of image archives stored worldwide is still insufficiently explored, and could be mined for known NEAs and other asteroids appearing occasionally in their fields. This data mining could be eased using a server to search and classify findings based on the asteroid class and the discovery date as "precoveries" or "recoveries". We built PRECOVERY, a public facility which uses the Virtual Observatory SkyBoT webservice of IMCCE to search for all known Solar System objects in a given observation. To datamine an entire archive, PRECOVERY requires the observing log in a standard format and outputs a database listing the sorted encounters of ...

  18. Photometric Study of Selected Asteroids

    Science.gov (United States)

    Shevchenko, Vasilij G.; Velichko, Feodor P.; Checha, Vitaly A.; Krugly, Yurij N.

    2014-07-01

    We performed photometric observations for eleven asteroids. New rotation periods were determined for five asteroids: 2812 Scaltriti (7.596 h), 4716 Urey (6.2 h), 7446 Hadrianus (3.402 h), (26657) 2000 SX293 (2.8 - 3.8 h), and (54063) 2000 GC136 (5.154 h).

  19. Directed Innovation of Business Models

    Directory of Open Access Journals (Sweden)

    Stelian Brad

    2016-06-01

    Full Text Available Business model innovation is an important issue to keep business competitive and increase company’s profits. Due to many market attractors, identification of appropriate paths of business model evolution is a painful and risky process. To improve decision’s effectiveness in this process, an architectural construct of analysis and conceptualization for business model innovation that combines directed evolution and blue ocean concepts is proposed in this paper under the name of directed innovation. It displays the key points where innovations would happen to direct adaptation of the business model towards sustainable competitiveness. Formulation of mature solutions is supported by inventive problem solving tools. The significance of the directed innovation approach is demonstrated in a case study dealing with business model innovation of a software company.

  20. Radar Observations of Asteroids

    Science.gov (United States)

    Ostro, S. J.

    2003-05-01

    During the past 25 years, radar investigations have provided otherwise unavailable information about the physical and dynamical properties of more than 200 asteroids. Measurements of the distribution of echo power in time delay and Doppler frequency provide two-dimensional images with spatial resolution as fine as a decameter. Sequences of delay-Doppler images can be used to produce geologically detailed three-dimensional models, to define the rotation state precisely, to constrain the internal density distribution, and to estimate the trajectory of the object's center of mass. Radar wavelengths (4 to 13 cm) and the observer's control of transmitted and received polarizations make the observations sensitive to near-surface bulk density and macroscopic structure. Since delay-Doppler positional measurements are orthogonal to optical angle measurements and typically have much finer fractional precision, they are powerful for refining orbits and prediction ephemerides. Radar astrometry can add decades or centuries to the interval over which an asteroid's close Earth approaches can accurately be predicted and can significantly refine collision probability estimates based on optical astrometry alone. In the highly unlikely case that a small body is on course for an Earth collision in this century, radar reconnaissance would almost immediately distinguish between an impact trajectory and a near miss and would dramatically reduce the difficulty and cost of any effort to prevent the collision. The sizes and rotation periods of radar-detected asteroids span more than four orders of magnitude. These observations have revealed both stony and metallic objects, elongated and nonconvex shapes as well as nearly featureless spheroids, small-scale morphology ranging from smoother than the lunar regolith to rougher than the rockiest terrain on Mars, craters and diverse linear structures, non-principal-axis spin states, contact binaries, and binary systems.

  1. Radar Investigations of Asteroids

    Science.gov (United States)

    Ostro, S.

    2004-05-01

    Radar investigations have provided otherwise unavailable information about the physical and dynamical properties of about 230 asteroids. Measurements of the distribution of echo power in time delay (range) and Doppler frequency (line-of-sight velocity) provide two-dimensional images with spatial resolution as fine as a decameter. Sequences of delay-Doppler images can be used to produce geologically detailed three-dimensional models, to define the rotation state precisely, to constrain the internal density distribution, and to estimate the trajectory of the object's center of mass. Radar wavelengths (4 to 13 cm) and the observer's control of transmitted and received polarizations make the observations sensitive to near-surface bulk density and macroscopic structure. Since delay-Doppler measurements are orthogonal to optical angle measurements and typically have much finer fractional precision, they are powerful for refining orbits and prediction ephemerides. Such astrometric measurements can add decades or centuries to the interval over which an asteroid's close Earth approaches can accurately be predicted and can significantly refine collision probability estimates based on optical astrometry alone. In the highly unlikely case that a small body is on course for an Earth collision in this century, radar reconnaissance would almost immediately distinguish between an impact trajectory and a near miss and would dramatically reduce the difficulty and cost of any effort to prevent the collision. The sizes and rotation periods of radar-detected asteroids span more than four orders of magnitude. The observations have revealed both stony and metallic objects, elongated and nonconvex shapes as well as nearly featureless spheroids, small-scale morphology ranging from smoother than the lunar regolith to rougher than the rockiest terrain on Mars, craters and diverse linear structures, non-principal-axis spin states, contact binaries, and binary systems.

  2. Asteroids and Comets

    CERN Document Server

    Fernandez, Yanga R; Howell, Ellen S; Woodney, Laura M

    2015-01-01

    Asteroids and comets are remnants from the era of Solar System formation over 4.5 billion years ago, and therefore allow us to address two fundamental questions in astronomy: what was the nature of our protoplanetary disk, and how did the process of planetary accretion occur? The objects we see today have suffered many geophysically-relevant processes in the intervening eons that have altered their surfaces, interiors, and compositions. In this chapter we review our understanding of the origins and evolution of these bodies, discuss the wealth of science returned from spacecraft missions, and motivate important questions to be addressed in the future.

  3. New Paradigms For Asteroid Formation

    CERN Document Server

    Johansen, Anders; Cuzzi, Jeffrey N; Morbidelli, Alessandro; Gounelle, Matthieu

    2015-01-01

    Asteroids and meteorites provide key evidence on the formation of planetesimals in the Solar System. Asteroids are traditionally thought to form in a bottom-up process by coagulation within a population of initially km-scale planetesimals. However, new models challenge this idea by demonstrating that asteroids of sizes from 100 to 1000 km can form directly from the gravitational collapse of small particles which have organised themselves in dense filaments and clusters in the turbulent gas. Particles concentrate passively between eddies down to the smallest scales of the turbulent gas flow and inside large-scale pressure bumps and vortices. The streaming instability causes particles to take an active role in the concentration, by piling up in dense filaments whose friction on the gas reduces the radial drift compared to that of isolated particles. In this chapter we review new paradigms for asteroid formation and compare critically against the observed properties of asteroids as well as constraints from meteo...

  4. Active Near Earth Asteroids

    Science.gov (United States)

    Jenniskens, Peter

    2015-08-01

    Past activity from Near Earth Asteroids is recorded in the meteoroid streams that cause our meteor showers. Automated meteoroid orbit surveys by photographic, low-light video, specular radar, and head-echo radar reflections are providing the first maps of meteor shower activity at different particle sizes. There are distinct differences in particle size distributions among streams. The underlaying mechanisms that created these streams are illuminated: fragmentation from spin-up or thermal stresses, meteoroid ejection by water vapor drag, and ejection of icy particles by CO and CO2 sublimation. The distribution of the meteoroid orbital elements probe the subsequent evolution by planetary perturbations and sample the range of dynamical processes to which Near Earth Asteroids are exposed. The non-stream "sporadic" meteors probe early stages in the evolution from meteoroid streams into the zodiacal dust cloud. We see that the lifetime of large meteoroids is generally not limited by collisions. Results obtained by the CAMS video survey of meteoroid orbits are compared to those from other orbit surveys. Since October 2010, over 200,000 meteoroid orbits have been measured. First results from an expansion into the southern hemisphere are also presented, as are first results from the measurement of main element compositions. Among the many streams detected so far, the Geminid and Sextantid showers stand out by having a relatively high particle density and derive from parent bodies that appear to have originated in the main belt.

  5. Asteroids Were Born Big

    CERN Document Server

    Morbidelli, Alessandro; Nesvorny, David; Levison, Harold F

    2009-01-01

    How big were the first planetesimals? We attempt to answer this question by conducting coagulation simulations in which the planetesimals grow by mutual collisions and form larger bodies and planetary embryos. The size frequency distribution (SFD) of the initial planetesimals is considered a free parameter in these simulations, and we search for the one that produces at the end objects with a SFD that is consistent with asteroid belt constraints. We find that, if the initial planetesimals were small (e.g. km-sized), the final SFD fails to fulfill these constraints. In particular, reproducing the bump observed at diameter D~100km in the current SFD of the asteroids requires that the minimal size of the initial planetesimals was also ~100km. This supports the idea that planetesimals formed big, namely that the size of solids in the proto-planetary disk ``jumped'' from sub-meter scale to multi-kilometer scale, without passing through intermediate values. Moreover, we find evidence that the initial planetesimals ...

  6. Managerial Stock Compensation and Risky Investment

    Directory of Open Access Journals (Sweden)

    Raluca Georgiana Nastasescu

    2009-06-01

    Full Text Available This study analyzes the relationship between the mix of CEO equity-based compensation, namely stock options and restricted stock, and firms' risky investment. In general, the theory suggests that long-term compensation aligns CEOs' and shareholders' interests by inducing the managers to undertake risky investment, which has a positive impact on longterm well-being of the firm. However, as my results show, it is important to distinguish between types of awards since they can have different effects on the riskiness of the firm. In this respect, I answer the question how are different types of stock based compensation related to the executives' determination to increase or not the intensity of the firm's risky investment? I find that awarding the CEOs preponderantly with stock options positively affects the firm's level of R&D investment. Conversely, a higher proportion of restricted stock in the CEO's compensation is related to lower investment in (risky R&D. The inverse relation of causality also holds. Firms that make intensive R&D investments are more likely to award their CEOs with more stock options relative to restricted stock. Overall, the results are consistent with the theoretical prediction, in that the managerial compensation scheme plays an important role in determining the level of R&D investment.

  7. Risky driving behaviors in Tehran, Iran.

    Science.gov (United States)

    Shams, Mohsen; Rahimi-Movaghar, Vafa

    2009-03-01

    Iran has one of the highest fatality rates due to road traffic crashes (RTC) in the world. The disability adjusted life years (DALYs) for RTC in Iran is more than 1,300,000 years, which is more than that for any other disease such as cardiovascular or cancer. We evaluated risky driving behaviors in Tehran, the capital of Iran. A retrospective analysis was conducted based on the data obtained from the Tehran Police Safety Driving Department. Offenses and crashes were studied in different municipal districts in Tehran from March 2006 to March 2007. The inclusion criteria were risky driving behaviors fined by the police. Nonbehavioral offences were excluded. There were 3,821,798 offenses in Tehran. Not wearing a seat belt was the most common (59%) example of risky driving behavior, followed by tailgating, not wearing motorcycle helmets, talking on the cell phone while driving, overtaking from the wrong side, speeding, not driving between the lanes, weaving in and out of traffic, left deviation, and changing lanes without signals. The most common causes of RTC in Tehran are speeding, overtaking from the wrong side, and the rapid changing of driving lanes. The study factors effective in preventing risky driving behaviors in Tehran is recommended. The consideration of specific characteristics of the municipal districts is necessary to reduce risky driving behaviors.

  8. Ion Beam Shepherd for Asteroid Deflection

    CERN Document Server

    Bombardelli, C

    2011-01-01

    We present a novel concept to impart a continuous thrust to an Earth threatening asteroid from a hovering spacecraft without need for physical attachment nor gravitational interaction with the asteroid. The concept involves an ion thruster placed at a distance of a few asteroid diameters directing a stream of quasi-neutral plasma against the asteroid surface resulting into a net transferred momentum. As the transmitted force is independent of the asteroid mass and size the method allows deflecting subkilometer asteroids with a spacecraft much lighter when compared to a gravity tractor spacecraft of equal deflection capability. The finding could make low-cost asteroid deflection missions possible in the coming years.

  9. Design study for asteroidal exploitation

    Science.gov (United States)

    Adams, Carl; Blissit, Jim; Jarrett, Dave; Sanner, Rob; Yanagawa, Koji

    1985-08-01

    A systematic approach to asteroidal exploitation for the 1990 to 2010 time frame is presented as an initial step toward expanding the use of space beyond the space station by providing a source of lower cost materials. With only a limited amount of information known about the asteroids, reconnaissance and exploration phases to determine the exact locations and compositions of several earth-approaching asteroids are required. Earth-based telescopes are used to locate and study the asteroids, while unmanned probes will return samples of asteroidal material to earth for analysis. After these phases are completed, the retrieval of a 35,000 metric ton piece of the asteroid Anteros is undertaken. A cargo transporter uses magnetoplasmadynamic (MPD) arcjets outbound and a mass-driver using asteroidal material inbound. A crew ship uses ion engines. Low thrust trajectories are used for both spacecraft. A materials processing facility will manufacture propellant pellets and retrieve non-propellant materials for spacecraft use. The cost is 1/10th that to transport the same materials from earth to high earth orbit. The project will cost 25 percent less if done in conjunction with a lunar and Martian base.

  10. Mine Planning for Asteroid Orebodies

    Science.gov (United States)

    Gertsch, L. S.; Gertsch, R. E.

    2000-01-01

    Given that an asteroid (or comet) has been determined to contain sufficient material of value to be potentially economic to exploit, a mining method must be selected and implemented. This paper discusses the engineering necessary to bring a mine online, and the opportunities and challenges inherent in asteroid mineral prospects. The very important step of orebody characterization is discussed elsewhere. The mining methods discussed here are based on enclosing the asteroid within a bag in some fashion, whether completely or partially. In general, asteroid mining methods based on bags will consist of the following steps. Not all will be required in every case, nor necessarily in this particular sequence. Some steps will be performed simultaneously. Their purpose is to extract the valuable material from the body of the asteroid in the most efficient, cost-effective manner possible. In approximate order of initiation, if not of conclusion, the steps are: 1. Tether anchoring to the asteroid. 2. Asteroid motion control. 3. Body/fragment restraint system placement. 4. Operations platform construction. 5. Bag construction. 6. Auxiliary and support equipment placement. 7. Mining operations. 8. Processing operations. 9. Product transport to markets.

  11. Double Asteroid Redirection Test (DART)

    Science.gov (United States)

    Cheng, A. F.

    2016-12-01

    The Asteroid Impact Deflection Assessment (AIDA) mission will be the first space experiment to demonstrate asteroid impact hazard mitigation by using a kinetic impactor. AIDA is a joint ESA-NASA cooperative project, consisting of the NASA Double Asteroid Redirection Test (DART) kinetic impactor mission and the ESA Asteroid Impact Mission (AIM) which is the rendezvous spacecraft. The AIDA target is the near-Earth binary asteroid 65803 Didymos. During the Didymos close approach to Earth in October, 2022, the DART spacecraft will impact the Didymos secondary at 6 km/s and deflect its trajectory, changing the orbital period of the binary. This change can be measured by Earth-based optical and radar observations. The primary goals of AIDA are to (1) perform a full-scale demonstration of asteroid deflection by kinetic impact; (2) measure the resulting deflection; and (3) validate and improve models for momentum transfer in high-speed impacts on an asteroid. The combined DART and AIM missions will provide the first measurements of momentum transfer efficiency from a kinetic impact at full scale on an asteroid, where the impact conditions of the projectile are known, and physical properties and internal structures of the target asteroid are also characterized. In addition to a measurable change in the binary orbit period, the DART kinetic impact is predicted to induce forced librations of the Didymos secondary of up to several degrees amplitude. It will furthermore make a crater that will be studied in detail by the AIM spacecraft, and it will release a volume of particulate ejecta that may be directly observable from Earth or even resolvable as a coma or an ejecta tail by ground-based telescopes. Updates will be given on DART status and study results.

  12. Asteroid Regolith Simulants: Development, Characteristics, and Testing

    Science.gov (United States)

    Britt, D. T.

    2015-12-01

    As part of a NASA Small Business Innovation Research (SBIR) award to the University of Central Florida and Deep Space Industries, we are developing a family of asteroid regolith simulants based on meteorite mineralogies but using terrestrial materials, to support NASAs exploration goals for asteroids. We are planning on developing five types of simulant based on the following meteorite types: CI-carbonaceous chondrite, CM-carbonaceous chondrite, Tagish Lake, L-ordinary chondrite, and iron. To the greatest extent reasonable (based on input costs and health/safety) we will duplicate the mineralogy, chemistry, oxidation state, hydration state, and particle size distribution found in regolith meteorites of each type. The major limitations on the fidelity of simulant will be health and safety issues for the users of the simulants. For example, much of the organic component of volatile-rich carbonaceous chondrites are in the form of Polycyclic Aromatic Hydrocarbons (PAHs). These are essentially combustion residues, possibly of complex regolith processing, with more carbon atoms than hydrogen. However, many PAHs are toxic, carcinogenic, and/or mutagenic. Several are banned in the European Union and California. This sort of material would endanger users, be impossible to distribute, and not make a useable regolith simulant. There are several reasonable, no-toxic alternatives to PAHs. We will report on the status of simulant development and the progress of our validation experiments.

  13. Images of an Activated Asteroid

    Science.gov (United States)

    Kohler, Susanna

    2016-08-01

    In late April of this year, asteroid P/2016 G1 (PANSTARRS) was discovered streaking through space, a tail of dust extending behind it. What caused this asteroids dust activity?Asteroid or Comet?Images of asteroid P/2016 G1 at three different times: late April, late May, and mid June. The arrow in the center panel points out an asymmetric feature that can be explained if the asteroid initially ejected material in a single direction, perhaps due to an impact. [Moreno et al. 2016]Asteroid P/2016 G1 is an interesting case: though it has the orbital elements of a main-belt asteroid it orbits at just under three times the EarthSun distance, with an eccentricity of e ~ 0.21 its appearance is closer to that of a comet, with a dust tail extending 20 behind it.To better understand the nature and cause of this unusual asteroids activity, a team led by Fernando Moreno (Institute of Astrophysics of Andalusia, in Spain) performed deep observations of P/2016 G1 shortly after its discovery. The team used the 10.4-meter Great Canary Telescope to image the asteroid over the span of roughly a month and a half.A Closer Look at P/2016 G1P/2016 G1 lies in the inner region of the main asteroid belt, so it is unlikely to have any ices that suddenly sublimated, causing the outburst. Instead, Moreno and collaborators suggest that the asteroids tail may have been caused by an impact that disrupted the parent body.To test this idea, the team used computer simulations to model their observations of P/2016 G1s dust tail. Based on their models, they demonstrate that the asteroid was likely activated on February 10 2016 roughly 350 days before it reached perihelion in its orbit and its activity was a short-duration event, lasting only ~24 days. The teams models indicate that over these 24 days, the asteroid lost around 20 million kilograms of dust, and at its maximum activity level, it was ejecting around 8 kg/s!Comparison of the observation from late May (panel a) and two models: one in which

  14. Human factors in cybersecurity; examining the link between Internet addiction, impulsivity, attitudes towards cybersecurity, and risky cybersecurity behaviours

    Directory of Open Access Journals (Sweden)

    Lee Hadlington

    2017-07-01

    Full Text Available The present study explored the relationship between risky cybersecurity behaviours, attitudes towards cybersecurity in a business environment, Internet addiction, and impulsivity. 538 participants in part-time or full-time employment in the UK completed an online questionnaire, with responses from 515 being used in the data analysis. The survey included an attitude towards cybercrime and cybersecurity in business scale, a measure of impulsivity, Internet addiction and a ‘risky’ cybersecurity behaviours scale. The results demonstrated that Internet addiction was a significant predictor for risky cybersecurity behaviours. A positive attitude towards cybersecurity in business was negatively related to risky cybersecurity behaviours. Finally, the measure of impulsivity revealed that both attentional and motor impulsivity were both significant positive predictors of risky cybersecurity behaviours, with non-planning being a significant negative predictor. The results present a further step in understanding the individual differences that may govern good cybersecurity practices, highlighting the need to focus directly on more effective training and awareness mechanisms.

  15. Structural Stability of Asteroids

    Science.gov (United States)

    Hirabayashi, Toshi

    This thesis develops a technique for analyzing the internal structure of an irregularly shaped asteroid. This research focuses on asteroid (216) Kleopatra, a few-hundred-kilometer-sized main belt asteroid spinning about its maximum moment of inertia axis with a rotation period of 5.385 hours, to motivate the techniques. While Ostro et al. [117] reported its dog bone-like shape, estimation of its size has been actively discussed. There are at least three different size estimates: Ostro et al., Descamps et al., and Marchis et al. Descamps et al. reported that (216) Kleopatra has satellites and obtained the mass of this object. This research consists of determination of possible failure modes of (216) Kleopatra and its subsequent detailed stress analysis, with each part including an estimation of the internal structure. The first part of this thesis considers the failure mode of Kleopatra and evaluates the size from it. Possible failure modes are modeled as either material shedding from the surface or plastic failure of the internal structure. The surface shedding condition is met when a zero-velocity curve with the same energy level as one of the dynamical equilibrium points attaches to the surface at the slowest spin period, while the plastic failure condition is characterized by extending the theorem by Holsapple (2008) that the yield condition of the averaged stress over the whole volume is identical to an upper bound for global failure. The prime result shows that while surface shedding does not occur at the current spin period and thus cannot result in the formation of the satellites, the neck may be situated near its plastic deformation state. From the failure condition, we also find that the size estimated by Descamps et al. (2011) is the most structurally stable. The second part of this thesis discusses finite element analyses with an assumption of an elastic-perfectly plastic material and a non-associated flow rule. The yield condition is modeled as the

  16. Smoking and Bone Healing - A Risky Surgical Combination

    Science.gov (United States)

    ... Risky Surgical Combination A A A | Print | Share Smoking and Bone Healing – A Risky Surgical Combination Imagine ... saying that they'd prefer patients to quit smoking. There hasn't been a great deal of ...

  17. Self - care strategies among risky profession workers

    Directory of Open Access Journals (Sweden)

    Katarína Vasková

    2015-01-01

    Full Text Available Taking care of oneself is crucial for maintaining one´s psychical and physical health. In the context of risky profession this topic can play an even more important role, because it can be the source of necessary information for improvement of coping capacity when one is confronted with crisis situations. The aim of the present study is to identify the most common forms of self-care among selected risky professions. In the second part is the attention focused on the comparison of the specificities of risky to non-risky professions in self-care. Methods: For data collection Self-regulation Self-care Questionnaire by authors Hricová and Lovaš (in press is used. The sample consists of two groups. In the first one participated 156 respondents, who worked in risky professions - namely police officers (60 at the age between 22 to 55 years (average age is 36.88, SD=9.49, fire fighters (46 at the age between 22 to 62 years (average age is 35.13, SD=8.31 and paramedics (50 at the age between 25 to 55 years (average age is 40.3, SD=6.62. 76.2% of the sample are men, 19.0% are women and 4,8% didn´t state their gender. The second sample consists of 161 participants who work in administrative, industry production or IT sphere. They were at the age between 23 to 61 years (average age is 38.01, SD=10.45. 74% of the sample are men and 21.7% are women. Results and discussion: Results confirmed the dominance of psychological self-care above physical among risky professions. To the forefront gets the need to live meaningful life, to fully use one´s skills and to be satisfied with one´s life and decisions. All this needs can be assigned to the necessity of sense, which could be seen as a result of everyday contact with critical and life threaten situations. Equally important sphere of self-care is the necessity of high-quality relationships, which doesn´t mean only relationships with family or friends. It is important to highlight also relationships with

  18. Near Earth Asteroid Scout Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In considering targets for human asteroid missions, there are several major factors that will make a significant difference in assessment of mission risks that...

  19. Solar wind tans young asteroids

    Science.gov (United States)

    2009-04-01

    A new study published in Nature this week reveals that asteroid surfaces age and redden much faster than previously thought -- in less than a million years, the blink of an eye for an asteroid. This study has finally confirmed that the solar wind is the most likely cause of very rapid space weathering in asteroids. This fundamental result will help astronomers relate the appearance of an asteroid to its actual history and identify any after effects of a catastrophic impact with another asteroid. ESO PR Photo 16a/09 Young Asteroids Look Old "Asteroids seem to get a ‘sun tan' very quickly," says lead author Pierre Vernazza. "But not, as for people, from an overdose of the Sun's ultraviolet radiation, but from the effects of its powerful wind." It has long been known that asteroid surfaces alter in appearance with time -- the observed asteroids are much redder than the interior of meteorites found on Earth [1] -- but the actual processes of this "space weathering" and the timescales involved were controversial. Thanks to observations of different families of asteroids [2] using ESO's New Technology Telescope at La Silla and the Very Large Telescope at Paranal, as well as telescopes in Spain and Hawaii, Vernazza's team have now solved the puzzle. When two asteroids collide, they create a family of fragments with "fresh" surfaces. The astronomers found that these newly exposed surfaces are quickly altered and change colour in less than a million years -- a very short time compared to the age of the Solar System. "The charged, fast moving particles in the solar wind damage the asteroid's surface at an amazing rate [3]", says Vernazza. Unlike human skin, which is damaged and aged by repeated overexposure to sunlight, it is, perhaps rather surprisingly, the first moments of exposure (on the timescale considered) -- the first million years -- that causes most of the aging in asteroids. By studying different families of asteroids, the team has also shown that an asteroid

  20. Asteroid named after CAS scientist

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ An asteroid has been named after CAS astronomy historian XI Zezong with the approval of the International Minor Planet Nomenclature Committee (IMPNC), announced China's National Astronomical Observatories at CAS (NAOC) on 17 August.

  1. Solar Radiation and Asteroidal Motion

    CERN Document Server

    Klacka, J

    2000-01-01

    Effects of solar wind and solar electromagnetic radiation on motion of asteroids are discussed. The results complete the statements presented in Vokrouhlick\\'{y} and Milani (2000). As for the effect of electromagnetic radiation, the complete equation of motion is presented to the first order in $v/c$ -- the shape of asteroid (spherical body is explicitly presented) and surface distribution of albedo should be taken into account. Optical quantities must be calculated in proper frame of reference.

  2. Children's Expressions of Exhilaration and Fear in Risky Play

    Science.gov (United States)

    Sandseter, Ellen Beate Hansen

    2009-01-01

    Children naturally seek and conduct exciting forms of play that involve a risk of physical injury (risky play). Even though several prior studies give descriptions of risky play, none of them deeply explore children's expressions of how they experience different kinds of risky play. This study aims to do that. The results from video observations…

  3. Risky and Cautious Decision Shifts in Small Groups.

    Science.gov (United States)

    Cline, Timothy R.; Cline, Rebecca J.

    1979-01-01

    Identifies and compares the patterns of communication of groups making risky and cautious decision shifts. Risky- and cautious-shift group discussions displayed nonrandom and statistically different distributional and sequential structures. Findings are discussed in terms of two explanations of the risky- shift phenomenon. (JMF)

  4. Is Utilitarianism Risky? How the Same Antecedents and Mechanism Produce Both Utilitarian and Risky Choices.

    Science.gov (United States)

    Lucas, Brian J; Galinsky, Adam D

    2015-07-01

    Philosophers and psychologists have long been interested in identifying factors that influence moral judgment. In the current analysis, we compare the literatures on moral psychology and decision making under uncertainty to propose that utilitarian choices are driven by the same forces that lead to risky choices. Spanning from neurocognitive to hormonal to interpersonal levels of analysis, we identify six antecedents that increase both utilitarian and risky choices (ventromedial prefrontal cortex brain lesions, psychopathology, testosterone, incidental positive affect, power, and social connection) and one antecedent that reduces these choices (serotonin activity). We identify the regulation of negative affect as a common mechanism through which the effects of each antecedent on utilitarian and risky choices are explained. By demonstrating that the same forces and the same underlying mechanism that produce risky choices also promote utilitarian choices, we offer a deeper understanding of how basic psychological systems underlie moral judgment. © The Author(s) 2015.

  5. Risky procurement with an insider bidder

    NARCIS (Netherlands)

    Boone, J.; Chen, R.; Goeree, J.K.

    2009-01-01

    Procurement auctions carry substantial risk when the value of the project is highly uncertain and known only to insiders. This paper reports the results from a series of experiments comparing the performance of three auction formats in such complex and risky settings. In the experiment, every bidder

  6. Romatoid Artritte Postural Denge ve Dusme Riski

    Directory of Open Access Journals (Sweden)

    Ahmet Inanir

    2013-02-01

    Full Text Available Amac: Bu calismanin amaci Romatoid Artritin denge ve dusme riski uzerine olan etkilerini degerlendirmektir. Gerec ve yontem: Calismaya toplam 70 olgu dahil edildi; bireylerin 35’i Romatoid artrit (11 erkek, 24 kadin, 35’i ise saglikli gonullulerden (16 erkek, 19 kadin olusmakta idi. Hastalar ve saglikli gonulluler denge ve dusme riski acisindan Biodekx Denge Sistemi (BDS ile degerlendirildi. Bulgular: Romatoid Artritli hastalarin yas ortalamasi 46.47±9.47 yil, kontrol grubunun ise 42.97±9.12 yil idi. Gruplar yas ve vucut kitle indeksi (VKI acisindan degerlendirildiginde istatistiksel olarak anlamli fark saptanmadi (sirasiyla, p=0.129, p=0.207. Gruplar Genel Stabilite Indeksi (GSI ve Antero-Posterior Stabilite Indeksi(APSI acisindan degerlendirildiginde istatistiksel olarak anlamli fark tespit edildi (sirasiyla, p<0.001 ve p=0.004. Benzer sekilde, Medio-Lateral Stabilite Indeksi (MLSI ve Dusme Riski Indeksi (DRI acisindan degerlendirildiginde de istatistiksel olarak anlamli fark saptandi (sirasiyla, p<0.001 ve p<0.001. Sonuc: Bu sonuclara gore, calismamizda Romatoid Artritin denge bozuklugu ve dusme riski ile iliskili oldugu ortaya konulmustur. [Cukurova Med J 2013; 38(1.000: 72-77

  7. Ambition: A Risky Adventure in Science Communication

    Science.gov (United States)

    McCaughrean, M.

    2016-03-01

    This article explores how the European Space Agency made a short science fiction film about the Rosetta mission to engage audiences in the core scientific and philosophical questions of the mission, and to manage expectations regarding the risky landing of Philae on the surface of Comet 67P/Churyumov-Gerasimenko.

  8. Risky behaviours among university students in Italy

    Directory of Open Access Journals (Sweden)

    Andrea Poscia

    2015-06-01

    Full Text Available BACKGROUND: The use of psychoactive substances is one of the most important public health issues. Tobacco, alcohol and illicit drugs are among the top risk factors for ill-health defined by World Health Organisation. The risky behaviours acquired in teenage can be magnified or decreased during university when a person starts having more awareness about the importance of own wellness. This paper describes the results of the project "Sportello Salute Giovani" ("Youth Health Information Desk" with respect to risky behaviours in a large sample of Italian university students. MATERIALS AND METHODS: 18 questions of the survey "Sportello Salute Giovani" dealing with risky behaviors, the use of psychoactive substances such as tobacco, alcohol and illicit drugs were included. Absolute and relative frequencies were calculated. Besides, chi square test were used to test the differences in sex, age class and socio-economic status. RESULTS: About 24% of the interviewed students currently smokes. 89% and 42.2% respectively drinks at least rarely or weekly beer, wine or spirits. About 40% of students smoked at least a joint and about 2% used other drugs (mostly cocaine. CONCLUSION: The "Sportello Salute Giovani" survey suggests that the frequency of risky behaviours in Italian university students is not reassuring, although they should be aware about the negative consequences on their and others health because of their educational level.

  9. Going for broke: dopamine influences risky choice.

    Science.gov (United States)

    Moschak, Travis M; Carelli, Regina M

    2014-10-01

    Dopamine neurons track reward by increasing or decreasing their firing rate when a reward is present or absent. In this issue of Neuron, Stopper et al. (2014) demonstrate that artificially eliminating these dopamine bursts or dips can alter risky decision-making.

  10. Parental Work Schedules and Adolescent Risky Behaviors

    Science.gov (United States)

    Han, Wen-Jui; Miller, Daniel P.; Waldfogel, Jane

    2010-01-01

    Using a large contemporary data set (the National Longitudinal Survey of Youth-Child Supplement), the authors examined the effects of parental work schedules on adolescent risky behaviors at age 13 or 14 and the mechanisms that might explain them. Structural equation modeling suggests mothers who worked more often at night spent significantly less…

  11. Anatomy of an Asteroid Breakup

    Science.gov (United States)

    Kohler, Susanna

    2017-05-01

    A team of scientists has observed the breakup of an asteroid as it orbits the Sun. In a new study, they reveal what theyve learned from their ground- and space-based observations of this disintegration.These Hubble images show the fragments of R3 in higher resolution over the span of October 2013 to February 2014. [Jewitt et al. 2017]Observations of DisintegrationActive asteroids are objects that move on asteroid-like orbits while displaying comet-like behavior. The cause of their activity can vary ranging from outgassing as the asteroid heats up in its solar approach, to expelled debris from a collision, to the entire asteroid flying apart because its spinning too fast.Led by David Jewitt (University of California at Los Angeles), a team of scientists has analyzed observations of the disintegrating asteroid P/2013 R3. The observations span two years and were made by a number of telescopes, including Hubble, Keck (in Hawaii), Magellan (in Chile), and the Very Large Telescope (in Chile).A schematic diagram of the different fragments of R3 and how they relate to each other. Black numbers estimate the fragment separation velocities; red numbers estimate the separation date. [Jewitt et al. 2017]Jewitt and collaborators then used these observations and a bit of modeling to understand what asteroid R3 was like originally, what its pieces are doing now, and what caused it to break up.Cause of the BreakupThe team found that P/2013 R3 broke up into at least 13 pieces, the biggest of which was likely no more than 100-200 meters in size. The original asteroid was probably less than 400 m in radius.By measuring the velocities of the fragments in the various observations, Jewitt and collaborators were able to work backward to determine when each piece broke off. They found that the fragmentation process was spread out over the span of roughly 5 months suggesting that the asteroids breakup wasnt impact-related (otherwise the fragmentation would likely have been all at once

  12. Refining the asteroid taxonomy by polarimetric observations

    Science.gov (United States)

    Belskaya, I. N.; Fornasier, S.; Tozzi, G. P.; Gil-Hutton, R.; Cellino, A.; Antonyuk, K.; Krugly, Yu. N.; Dovgopol, A. N.; Faggi, S.

    2017-03-01

    We present new results of polarimetric observations of 15 main belt asteroids of different composition. By merging new and published data we determined polarimetric parameters characterizing individual asteroids and mean values of the same parameters characterizing different taxonomic classes. The majority of asteroids show polarimetric phase curves close to the average curve of the corresponding class. We show that using polarimetric data it is possible to refine asteroid taxonomy and derive a polarimetric classification for 283 main belt asteroids. Polarimetric observations of asteroid (21) Lutetia are found to exhibit possible variations of the position angle of the polarization plane over the surface.

  13. Excluding interlopers from asteroid families

    Science.gov (United States)

    Novakovic, B.; Radovic, V.

    2014-07-01

    Introduction: Asteroid families are believed to have originated from catastrophic collisions among asteroids. They are a very important subject of Solar System investigation, because practically any research topic carried out in asteroid-related science sooner or later encounters problems pertaining to asteroid families. One basic problem encountered when dealing with families is to determine reliably the list of its members, i.e. to reduce the number of interlopers as much as possible. This is an important problem, because many conclusions derived from analyses of the physical properties of family members must be necessarily based on firm and well established membership. However, as the number of known asteroids increases fast it becomes more and more difficult to obtain robust list of members of an asteroid family. To cope with these challenges we are proposing a new approach that may help to significantly reduce presence of interlopers among the family members. This method should be particularly useful once additional information become available, including primarily spectro-photometric data. This is exactly the kind of information that will be provided by Gaia. Metodology: Families (and their members) have been commonly identified by analysing the distribution of asteroids in the space of proper orbital elements, using the Hierarchical Clustering Method (HCM) [1]. A well-known drawback of the HCM based on the single linkage rule is the so-called chaining phenomenon: first concentrations naturally tend to incorporate nearby groups, forming a kind of 'chain'. Thus, any family membership obtained by the pure HCM must unavoidably include some interlopers. The method we are proposing here could be used to identify these interlopers, with its main advantage being an ability to significantly reduce the chaining effect. The method consists of three main steps. First we determine an asteroid family members by applying the HCM to the catalogue of proper elements obtained

  14. Asteroid airburst altitude vs. strength

    Science.gov (United States)

    Robertson, Darrel; Wheeler, Lorien; Mathias, Donovan

    2016-10-01

    Small NEO asteroids (<Ø140m) may not be a threat on a national or global level but can still cause a significant amount of local damage as demonstrated by the Chelyabinsk event where there was over $33 million worth of damage (1 billion roubles) and 1500 were injured, mostly due to broken glass. The ground damage from a small asteroid depends strongly on the altitude at which they "burst" where most of the energy is deposited in the atmosphere. The ability to accurately predict ground damage is useful in determining appropriate evacuation or shelter plans and emergency management.Strong asteroids, such as a monolithic boulder, fail and create peak energy deposition close to the altitude at which ram dynamic pressure exceeds the material cohesive strength. Weaker asteroids, such as a rubble pile, structurally fail at higher altitude, but it requires the increased aerodynamic pressure at lower altitude to disrupt and disperse the rubble. Consequently the resulting airbursts have a peak energy deposition at similar altitudes.In this study hydrocode simulations of the entry and break-up of small asteroids were performed to examine the effect of strength, size, composition, entry angle, and speed on the resulting airburst. This presentation will show movies of the simulations, the results of peak burst height, and the comparison to semi-analytical models.

  15. Biopharma business models in Canada.

    Science.gov (United States)

    March-Chordà, I; Yagüe-Perales, R M

    2011-08-01

    This article provides new insights into the different strategy paths or business models currently being implemented by Canadian biopharma companies. Through a case-study methodology, seven biopharma companies pertaining to three business models were analyzed, leading to a broad set of results emerging from the following areas: activity, business model and strategy; management and human resources; and R&D, technology and innovation strategy. The three business models represented were: model 1 (conventional biotech oriented to new drug development, radical innovation and search for discoveries); model 2 (development of a technology platform, usually in proteomics and bioinformatics); and model 3 (incremental innovation, with shorter and less risky development timelines). Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Optimal Investment Strategy for Risky Assets

    OpenAIRE

    Sergei Maslov; Yi-Cheng Zhang

    1998-01-01

    We design an optimal strategy for investment in a portfolio of assets subject to a multiplicative Brownian motion. The strategy provides the maximal typical long-term growth rate of investor's capital. We determine the optimal fraction of capital that an investor should keep in risky assets as well as weights of different assets in an optimal portfolio. In this approach both average return and volatility of an asset are relevant indicators determining its optimal weight. Our results are parti...

  17. A Gravitational Tractor for Towing Asteroids

    CERN Document Server

    Lu, E T; Lu, Edward T.; Categories, Stanley G. Love

    2005-01-01

    We present a concept for a spacecraft that can controllably alter the trajectory of an Earth threatening asteroid using gravity as a towline. The spacecraft hovers near the asteroid with thrusters angled outward so the exhaust does not impinge on the surface. This deflection method is insensitive to the structure, surface properties, and rotation state of the asteroid.

  18. Benchmarking Asteroid-Deflection Experiment

    Science.gov (United States)

    Remington, Tane; Bruck Syal, Megan; Owen, John Michael; Miller, Paul L.

    2016-10-01

    An asteroid impacting Earth could have devastating consequences. In preparation to deflect or disrupt one before it reaches Earth, it is imperative to have modeling capabilities that adequately simulate the deflection actions. Code validation is key to ensuring full confidence in simulation results used in an asteroid-mitigation plan. We are benchmarking well-known impact experiments using Spheral, an adaptive smoothed-particle hydrodynamics code, to validate our modeling of asteroid deflection. We describe our simulation results, compare them with experimental data, and discuss what we have learned from our work. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-695540

  19. On the Astrid asteroid family

    CERN Document Server

    Carruba, V

    2016-01-01

    Among asteroid families, the Astrid family is peculiar because of its unusual inclination distribution. Objects at $a\\simeq$~2.764 au are quite dispersed in this orbital element, giving the family a "crab-like" appearance. Recent works showed that this feature is caused by the interaction of the family with the $s-s_C$ nodal secular resonance with Ceres, that spreads the inclination of asteroids near its separatrix. As a consequence, the currently observed distribution of the $v_W$ component of terminal ejection velocities obtained from inverting Gauss equation is quite leptokurtic, since this parameter mostly depends on the asteroids inclination. The peculiar orbital configuration of the Astrid family can be used to set constraints on key parameters describing the strength of the Yarkovsky force, such as the bulk and surface density and the thermal conductivity of surface material. By simulating various fictitious families with different values of these parameters, and by demanding that the current value of ...

  20. Dynamics of Rotationally Fissioned Asteroids

    Science.gov (United States)

    Jacobson, Seth A.; Scheeres, D. J.

    2010-10-01

    We present a model for near-Earth asteroid (NEA) rotational fission that results in the evolution of all observed types of NEA systems: synchronous binaries, asteroid pairs, doubly synchronous binaries, high-e binaries, ternary systems, and contact binaries. The model consists of "rubble pile” asteroid geophysics, the YORP and binary YORP effects, and mutual gravitational interactions. An NEA can be modeled as a ``rubble pile"--a collection of gravitationally bound boulders with a distribution of size scales and very little tensile strength between them. The YORP effect torques a "rubble pile” asteroid until the asteroid reaches its disruption spin limit, and then two collections of boulders will enter into orbit about each other determined by the largest distance between mass centers. This binary system dynamically evolves under the effects of non-spherical gravitational potentials, solar gravitational perturbations, and mutual body tides. The coupling between the spin states and orbit state chaotically drives the system into the observed asteroid classes with mass ratio, q, distinguishing two evolutionary tracks. High mass ratio systems, q>0.2, evolve tidally into doubly synchronous binaries and then continued to be evolved by BYORP. Low mass ratio systems, qfission, creating a chaotic ternary system. We call this new process secondary fission. The resulting triple system may eject one body or, more often, send one into a slow speed impact with the primary. These processes tend to stabilize the initially chaotic binaries to create synchronous binaries. These results emphasize the importance of the initial component size distribution and configuration within the parent body. This work is supported by NASA's PGG and OPR programs through grants: NNX08AL51G and NNX09AU23G.

  1. Project RAMA: Reconstructing Asteroids Into Mechanical Automata

    Science.gov (United States)

    Dunn, Jason; Fagin, Max; Snyder, Michael; Joyce, Eric

    2017-01-01

    Many interesting ideas have been conceived for building space-based infrastructure in cislunar space. From O'Neill's space colonies, to solar power satellite farms, and even prospecting retrieved near earth asteroids. In all the scenarios, one thing remained fixed - the need for space resources at the outpost. To satisfy this need, O'Neill suggested an electromagnetic railgun to deliver resources from the lunar surface, while NASA's Asteroid Redirect Mission called for a solar electric tug to deliver asteroid materials from interplanetary space. At Made In Space, we propose an entirely new concept. One which is scalable, cost effective, and ensures that the abundant material wealth of the inner solar system becomes readily available to humankind in a nearly automated fashion. We propose the RAMA architecture, which turns asteroids into self-contained spacecraft capable of moving themselves back to cislunar space. The RAMA architecture is just as capable of transporting conventional-sized asteroids on the 10-meter length scale as transporting asteroids 100 meters or larger, making it the most versatile asteroid retrieval architecture in terms of retrieved-mass capability. This report describes the results of the Phase I study funded by the NASA NIAC program for Made In Space to establish the concept feasibility of using space manufacturing to convert asteroids into autonomous, mechanical spacecraft. Project RAMA, Reconstituting Asteroids into Mechanical Automata, is designed to leverage the future advances of additive manufacturing (AM), in-situ resource utilization (ISRU) and in-situ manufacturing (ISM) to realize enormous efficiencies in repeated asteroid redirect missions. A team of engineers at Made In Space performed the study work with consultation from the asteroid mining industry, academia, and NASA. Previous studies for asteroid retrieval have been constrained to studying only asteroids that are both large enough to be discovered, and small enough to be

  2. Flying Through Dust From Asteroids

    Science.gov (United States)

    Kohler, Susanna

    2016-11-01

    How can we tell what an asteroid is made of? Until now, weve relied on remote spectral observations, though NASAs recently launched OSIRIS-REx mission may soon change this by landing on an asteroid and returning with a sample.But what if we could learn more about the asteroids near Earth without needing to land on each one? It turns out that we can by flying through their dust.The aerogel dust collector of the Stardust mission. [NASA/JPL/Caltech]Ejected CluesWhen an airless body is impacted by the meteoroids prevalent throughout our solar system, ejecta from the body are flung into the space around it. In the case of small objects like asteroids, their gravitational pull is so weak that most of the ejected material escapes, forming a surrounding cloud of dust.By flying a spacecraft through this cloud, we could perform chemical analysis of the dust, thereby determining the asteroids composition. We could even capture some of the dust during a flyby (for example, by using an aerogel collector like in the Stardust mission) and bring it back home to analyze.So whats the best place to fly a dust-analyzing or -collecting spacecraft? To answer this, we need to know what the typical distribution of dust is around a near-Earth asteroid (NEA) a problem that scientists Jamey Szalay (Southwest Research Institute) and Mihly Hornyi (University of Colorado Boulder) address in a recent study.The colors show the density distribution for dust grains larger than 0.3 m around a body with a 10-km radius. The distribution is asymmetric, with higher densities on the apex side, shown here in the +y direction. [Szalay Hornyi 2016]Moon as a LaboratoryTo determine typical dust distributions around NEAs, Szalay and Hornyi first look at the distribution of dust around our own Moon, caused by the same barrage of meteorites wed expect to impact NEAs. The Moons dust cloud was measured in situ in 2013 and 2014 by the Lunar Dust Experiment (LDEX) on board the Lunar Atmosphere and Dust Environment

  3. Spectral Classification of Asteroids by Random Forest

    Science.gov (United States)

    Huang, C.; Ma, Y. H.; Zhao, H. B.; Lu, X. P.

    2016-09-01

    With the increasing asteroid spectral and photometric data, a variety of classification methods for asteroids have been proposed. This paper classifies asteroids based on the observations of Sloan Digital Sky Survey (SDSS) Moving Object Catalogue (MOC) by using the random forest algorithm. With the training data derived from the taxonomies of Tholen, Bus, Lazzaro, DeMeo, and Principal Component Analysis, we classify 48642 asteroids according to g, r, i, and z SDSS magnitudes. In this way, asteroids are divided into 8 spectral classes (C, X, S, B, D, K, L, and V).

  4. AsteroidZoo: A New Zooniverse project to detect asteroids and improve asteroid detection algorithms

    Science.gov (United States)

    Beasley, M.; Lewicki, C. A.; Smith, A.; Lintott, C.; Christensen, E.

    2013-12-01

    We present a new citizen science project: AsteroidZoo. A collaboration between Planetary Resources, Inc., the Zooniverse Team, and the Catalina Sky Survey, we will bring the science of asteroid identification to the citizen scientist. Volunteer astronomers have proved to be a critical asset in identification and characterization of asteroids, especially potentially hazardous objects. These contributions, to date, have required that the volunteer possess a moderate telescope and the ability and willingness to be responsive to observing requests. Our new project will use data collected by the Catalina Sky Survey (CSS), currently the most productive asteroid survey, to be used by anyone with sufficient interest and an internet connection. As previous work by the Zooniverse has demonstrated, the capability of the citizen scientist is superb at classification of objects. Even the best automated searches require human intervention to identify new objects. These searches are optimized to reduce false positive rates and to prevent a single operator from being overloaded with requests. With access to the large number of people in Zooniverse, we will be able to avoid that problem and instead work to produce a complete detection list. Each frame from CSS will be searched in detail, generating a large number of new detections. We will be able to evaluate the completeness of the CSS data set and potentially provide improvements to the automated pipeline. The data corpus produced by AsteroidZoo will be used as a training environment for machine learning challenges in the future. Our goals include a more complete asteroid detection algorithm and a minimum computation program that skims the cream of the data suitable for implemention on small spacecraft. Our goal is to have the site become live in the Fall 2013.

  5. Reducing Risky Security Behaviours: Utilising Affective Feedback to Educate Users

    Directory of Open Access Journals (Sweden)

    Lynsay A. Shepherd

    2014-11-01

    Full Text Available Despite the number of tools created to help end-users reduce risky security behaviours, users are still falling victim to online attacks. This paper proposes a browser extension utilising affective feedback to provide warnings on detection of risky behaviour. The paper provides an overview of behaviour considered to be risky, explaining potential threats users may face online. Existing tools developed to reduce risky security behaviours in end-users have been compared, discussing the success rates of various methodologies. Ongoing research is described which attempts to educate users regarding the risks and consequences of poor security behaviour by providing the appropriate feedback on the automatic recognition of risky behaviour. The paper concludes that a solution utilising a browser extension is a suitable method of monitoring potentially risky security behaviour. Ultimately, future work seeks to implement an affective feedback mechanism within the browser extension with the aim of improving security awareness.

  6. Simultaneous Mass Determination for Gravitationally Coupled Asteroids

    Science.gov (United States)

    Baer, James; Chesley, Steven R.

    2017-08-01

    The conventional least-squares asteroid mass determination algorithm allows us to solve for the mass of a large subject asteroid that is perturbing the trajectory of a smaller test asteroid. However, this algorithm is necessarily a first approximation, ignoring the possibility that the subject asteroid may itself be perturbed by the test asteroid, or that the encounter’s precise geometry may be entangled with encounters involving other asteroids. After reviewing the conventional algorithm, we use it to calculate the masses of 30 main-belt asteroids. Compared to our previous results, we find new mass estimates for eight asteroids (11 Parthenope, 27 Euterpe, 51 Neimausa, 76 Freia, 121 Hermione, 324 Bamberga, 476 Hedwig, and 532 Herculina) and significantly more precise estimates for six others (2 Pallas, 3 Juno, 4 Vesta, 9 Metis, 16 Psyche, and 88 Thisbe). However, we also find that the conventional algorithm yields questionable results in several gravitationally coupled cases. To address such cases, we describe a new algorithm that allows the epoch state vectors of the subject asteroids to be included as solve-for parameters, allowing for the simultaneous solution of the masses and epoch state vectors of multiple subject and test asteroids. We then apply this algorithm to the same 30 main-belt asteroids and conclude that mass determinations resulting from current and future high-precision astrometric sources (such as Gaia) should conduct a thorough search for possible gravitational couplings and account for their effects.

  7. Astronomical Observations of Volatiles on Asteroids

    CERN Document Server

    Rivkin, Andrew S; Emery, Joshua P; Howell, Ellen S; Licandro, Javier; Takir, Driss; Vilas, Faith

    2015-01-01

    We have long known that water and hydroxyl are important components in meteorites and asteroids. However, in the time since the publication of Asteroids III, evolution of astronomical instrumentation, laboratory capabilities, and theoretical models have led to great advances in our understanding of H2O/OH on small bodies, and spacecraft observations of the Moon and Vesta have important implications for our interpretations of the asteroidal population. We begin this chapter with the importance of water/OH in asteroids, after which we will discuss their spectral features throughout the visible and near-infrared. We continue with an overview of the findings in meteorites and asteroids, closing with a discussion of future opportunities, the results from which we can anticipate finding in Asteroids V. Because this topic is of broad importance to asteroids, we also point to relevant in-depth discussions elsewhere in this volume.

  8. Astronomical observations of volatiles on asteroids

    Science.gov (United States)

    Rivkin, Andrew S.; Campins, Humberto; Emery, Joshua P.; Howell, Ellen S.; Licandro, Javier; Takir, Driss; Vilas, Faith; Michel, Patrick; DeMeo, Francesca E.; Bottke, William F.

    2015-01-01

    We have long known that water and hydroxyl are important components in meteorites and asteroids. However, in the time since the publication of Asteroids III, evolution of astronomical instrumentation, laboratory capabilities, and theoretical models have led to great advances in our understanding of H2O/OH on small bodies, and spacecraft observations of the Moon and Vesta have important implications for our interpretations of the asteroidal population. We begin this chapter with the importance of water/OH in asteroids, after which we will discuss their spectral features throughout the visible and near-infrared. We continue with an overview of the findings in meteorites and asteroids, closing with a discussion of future opportunities, the results from which we can anticipate finding in Asteroids V. Because this topic is of broad importance to asteroids, we also point to relevant in-depth discussions elsewhere in this volume.

  9. Asteroid taxonomic signatures from photometric phase curves

    CERN Document Server

    Oszkiewicz, D A; Wasserman, L H; Muinonen, K; Penttilä, A; Pieniluoma, T; Trilling, D E; Thomas, C A

    2012-01-01

    We explore the correlation between an asteroid's taxonomy and photometric phase curve using the H, G12 photometric phase function, with the shape of the phase function described by the single parameter G12. We explore the usability of G12 in taxonomic classification for individual objects, asteroid families, and dynamical groups. We conclude that the mean values of G12 for the considered taxonomic complexes are statistically different, and also discuss the overall shape of the G12 distribution for each taxonomic complex. Based on the values of G12 for about half a million asteroids, we compute the probabilities of C, S, and X complex membership for each asteroid. For an individual asteroid, these probabilities are rather evenly distributed over all of the complexes, thus preventing meaningful classification. We then present and discuss the G12 distributions for asteroid families, and predict the taxonomic complex preponderance for asteroid families given the distribution of G12 in each family. For certain ast...

  10. The empty primordial asteroid belt.

    Science.gov (United States)

    Raymond, Sean N; Izidoro, Andre

    2017-09-01

    The asteroid belt contains less than a thousandth of Earth's mass and is radially segregated, with S-types dominating the inner belt and C-types the outer belt. It is generally assumed that the belt formed with far more mass and was later strongly depleted. We show that the present-day asteroid belt is consistent with having formed empty, without any planetesimals between Mars and Jupiter's present-day orbits. This is consistent with models in which drifting dust is concentrated into an isolated annulus of terrestrial planetesimals. Gravitational scattering during terrestrial planet formation causes radial spreading, transporting planetesimals from inside 1 to 1.5 astronomical units out to the belt. Several times the total current mass in S-types is implanted, with a preference for the inner main belt. C-types are implanted from the outside, as the giant planets' gas accretion destabilizes nearby planetesimals and injects a fraction into the asteroid belt, preferentially in the outer main belt. These implantation mechanisms are simple by-products of terrestrial and giant planet formation. The asteroid belt may thus represent a repository for planetary leftovers that accreted across the solar system but not in the belt itself.

  11. A note on calculating the optimal risky portfolio

    OpenAIRE

    Reha H. Tütüncü

    2001-01-01

    Given a number of risky assets and a riskless asset, the set of efficient portfolios in the mean-variance optimization sense are combinations of the riskless asset and a unique optimal risky portfolio. This note shows how a simple modification of Markowitz' method of critical lines can be used to determine the optimal risky portfolio in a faster, more reliable, and more memory-efficient way than the standard approaches.

  12. The Asteroid Redirect Mission (ARM)

    Science.gov (United States)

    Abell, Paul; Gates, Michele; Johnson, Lindley; Chodas, Paul; Mazanek, Dan; Reeves, David; Ticker, Ronald

    2016-07-01

    To achieve its long-term goal of sending humans to Mars, the National Aeronautics and Space Administration (NASA) plans to proceed in a series of incrementally more complex human spaceflight missions. Today, human flight experience extends only to Low-Earth Orbit (LEO), and should problems arise during a mission, the crew can return to Earth in a matter of minutes to hours. The next logical step for human spaceflight is to gain flight experience in the vicinity of the Moon. These cis-lunar missions provide a "proving ground" for the testing of systems and operations while still accommodating an emergency return path to the Earth that would last only several days. Cis-lunar mission experience will be essential for more ambitious human missions beyond the Earth-Moon system, which will require weeks, months, or even years of transit time. In addition, NASA has been given a Grand Challenge to find all asteroid threats to human populations and know what to do about them. Obtaining knowledge of asteroid physical properties combined with performing technology demonstrations for planetary defense provide much needed information to address the issue of future asteroid impacts on Earth. Hence the combined objectives of human exploration and planetary defense give a rationale for the Asteroid Re-direct Mission (ARM). Mission Description: NASA's ARM consists of two mission segments: 1) the Asteroid Redirect Robotic Mission (ARRM), the first robotic mission to visit a large (greater than ~100 m diameter) near-Earth asteroid (NEA), collect a multi-ton boulder from its surface along with regolith samples, demonstrate a planetary defense technique, and return the asteroidal material to a stable orbit around the Moon; and 2) the Asteroid Redirect Crewed Mission (ARCM), in which astronauts will take the Orion capsule to rendezvous and dock with the robotic vehicle, conduct multiple extravehicular activities to explore the boulder, and return to Earth with samples. NASA's proposed

  13. Asteroid magnitudes, UBV colors, and IRAS albedos and diameters

    Science.gov (United States)

    Tedesco, Edward F.

    1989-01-01

    This paper lists absolute magnitudes and slope parameters for known asteroids numbered through 3318. The values presented are those used in reducing asteroid IR flux data obtained with the IRAS. U-B colors are given for 938 asteroids, and B-V colors are given for 945 asteroids. The IRAS albedos and diameters are tabulated for 1790 asteroids.

  14. Asteroids. Prospective energy and material resources

    Energy Technology Data Exchange (ETDEWEB)

    Badescu, Viorel (ed.) [Bucharest Polytechnic Univ. (Romania). Candida Oancea Institute

    2013-11-01

    Recent research on Prospective Energy and Material Resources on Asteroids. Carefully edited book dedicated to Asteroids prospective energy and material resources. Written by leading experts in the field. The Earth has limited material and energy resources while these resources in space are virtually unlimited. Further development of humanity will require going beyond our planet and exploring of extraterrestrial resources and sources of unlimited power. Thus far, all missions to asteroids have been motivated by scientific exploration. However, given recent advancements in various space technologies, mining asteroids for resources is becoming ever more feasible. A significant portion of asteroids value is derived from their location; the required resources do not need to be lifted at a great expense from the surface of the Earth. Resources derived from Asteroid not only can be brought back to Earth but could also be used to sustain human exploration of space and permanent settlements in space. This book investigates asteroids' prospective energy and material resources. It is a collection of topics related to asteroid exploration, and utilization. It presents past and future technologies and solutions to old problems that could become reality in our life time. The book therefore is a great source of condensed information for specialists involved in current and impending asteroid-related activities and a good starting point for space researchers, inventors, technologists and potential investors. Written for researchers, engineers, and businessmen interested in asteroids' exploration and exploitation.

  15. Asteroid exploration and utilization: The Hawking explorer

    Science.gov (United States)

    Carlson, Alan; Date, Medha; Duarte, Manny; Erian, Neil; Gafka, George; Kappler, Peter; Patano, Scott; Perez, Martin; Ponce, Edgar; Radovich, Brian

    1991-01-01

    The Earth is nearing depletion of its natural resources at a time when human beings are rapidly expanding the frontiers of space. The resources which may exist on asteroids could have enormous potential for aiding and enhancing human space exploration as well as life on Earth. With the possibly limitless opportunities that exist, it is clear that asteroids are the next step for human existence in space. This report comprises the efforts of NEW WORLDS, Inc. to develop a comprehensive design for an asteroid exploration/sample return mission. This mission is a precursor to proof-of-concept missions that will investigate the validity of mining and materials processing on an asteroid. Project STONER (Systematic Transfer of Near Earth Resources) is based on two utilization scenarios: (1) moving an asteroid to an advantageous location for use by Earth; and (2) mining an asteroids and transporting raw materials back to Earth. The asteroid explorer/sample return mission is designed in the context of both scenarios and is the first phase of a long range plane for humans to utilize asteroid resources. The report concentrates specifically on the selection of the most promising asteroids for exploration and the development of an exploration scenario. Future utilization as well as subsystem requirements of an asteroid sample return probe are also addressed.

  16. Business ethics

    OpenAIRE

    Duong, Thi

    2002-01-01

    The goal of this paper is to present examples of business ethics issues. What is business ethics, things concerned in this field are and why it is needed and important when doing business? The concept of business ethics has connotations to provision, rules and standards in directing the behavior of actors in the business. Business ethics involves compliance with the law, the implementation of ethical responsibilities of a business, the protection of the rights of those who are related to the ...

  17. The Asteroid 1998 QE2

    Science.gov (United States)

    Vodniza, Alberto Q.; Pereira, M. R.; Arecibo Observatory Team; JPL Target Asteroids Team

    2013-10-01

    This big asteroid was at 5.8 millions of kilometers from the Earth on May 31 (2013) and it has a diameter of 2.7 km. The radar images obtained by JPL showed that the period of rotation around its axis is close to five hours. Hills. K (2013) reported that the period is of 5.281 +/- 0.002 hours. On June 4 the team of Goldstone-Arecibo found a period of 4.75 +/- 0.01 hours. We also contributed with the light and phase curves to estimate the period by means of the telescope (with red filter). The radar imagery (JPL and Arecibo) revealed that 1998 QE2 has a moon, and we captured a mutual event (eclipse). From our Observatory, located in Pasto-Colombia, we captured several pictures, videos and astrometry data during several days. Our data was published by the Minor Planet Center (MPC) and also appears at the web page of NEODyS. The pictures of the asteroid were captured with the following equipment: CGE PRO 1400 CELESTRON (f/11 Schmidt-Cassegrain Telescope) and STL-1001 SBIG camera. We obtained the light curve of the body. Astrometry was carried out, and we calculated the orbital elements. We obtained the following orbital parameters: eccentricity = 0.5692181, semi-major axis = 2.41104631 A.U, orbital inclination = 12.82771 deg, longitude of the ascending node = 250.16876 deg, argument of perihelion = 345.61328 deg, mean motion = 0.26326658 deg/d, perihelion distance = 1.03863508 A.U, aphelion distance = 3.78345755 A.U. The asteroid has an orbital period of 3.74 years The parameters were calculated based on 191 observations (2013 May: 17-24) with mean residual = 0.162 arcseconds. A video of the asteroid from our Observatory was published on the main page of the “SPACEWEATHER” web: http://www.spaceweather.com/archive.php?view=1&day=21&month=05&year=2013 Note: The autors would like to thank to: Dr. Alessondra Springmann (Arecibo Observatory), Dr. Petr Pravec (Czech Republic), Dr. Lance Benner (JPL), Dr. Carl Hergenrother (Target Asteroids Team), and Dr. Dolores Hill

  18. Pubertal Development and Peer Influence on Risky Decision Making

    Science.gov (United States)

    Kretsch, Natalie; Harden, Kathryn Paige

    2014-01-01

    Adolescents engage in more risky behavior when they are with peers and show, on average, heightened susceptibility to peer influence relative to children and adults. However, individual differences in susceptibility to peer influence are not well understood. The current study examined whether the effect of peers on adolescents' risky decision…

  19. Social-cognitive correlates of risky adolescent cycling behavior

    Directory of Open Access Journals (Sweden)

    Ruiter Robert AC

    2010-07-01

    Full Text Available Abstract Background Bicycle use entails high safety and health risks especially for adolescents. Most safety education programs aimed at adolescents focus on accident statistics and risk perceptions. This paper proposes the investigation of the social-cognitive correlates of risky cycling behaviors of adolescents prior to developing safety education programs. Method Secondary school students aged 13 to 18 years (n = 1446 filled out questionnaires regarding bicycle behavior, risky intentions, accident experience, and social-cognitive determinants as suggested by the theory of planned behavior. Results Regression analysis revealed that the proximal variables (i.e., self-efficacy, attitudes towards drunk driving, personal norm regarding safekeeping of self and others, and compared risk were able to predict 17% of the variance of risky behavior and 23% of the variance of risky intentions. The full model explained respectively 29% and 37% of the variance in risky behavior and risky intentions. Adolescents with positive attitudes towards risky behavior and low sense of responsibility report risky behavior, even when having been (close to an accident. Conclusions Adolescents realize whether they are risk takers or not. This implies that the focus of education programs should not be on risk perceptions, but on decreasing positive attitudes towards alcohol in traffic and increasing sense of responsibility instead. Cognitions regarding near accidents should be studied, the role of safe cycling self-efficacy is unclear.

  20. Social-cognitive correlates of risky adolescent cycling behavior.

    Science.gov (United States)

    Feenstra, Hans; Ruiter, Robert A C; Kok, Gerjo

    2010-07-12

    Bicycle use entails high safety and health risks especially for adolescents. Most safety education programs aimed at adolescents focus on accident statistics and risk perceptions. This paper proposes the investigation of the social-cognitive correlates of risky cycling behaviors of adolescents prior to developing safety education programs. Secondary school students aged 13 to 18 years (n = 1446) filled out questionnaires regarding bicycle behavior, risky intentions, accident experience, and social-cognitive determinants as suggested by the theory of planned behavior. Regression analysis revealed that the proximal variables (i.e., self-efficacy, attitudes towards drunk driving, personal norm regarding safekeeping of self and others, and compared risk) were able to predict 17% of the variance of risky behavior and 23% of the variance of risky intentions. The full model explained respectively 29% and 37% of the variance in risky behavior and risky intentions. Adolescents with positive attitudes towards risky behavior and low sense of responsibility report risky behavior, even when having been (close to) an accident. Adolescents realize whether they are risk takers or not. This implies that the focus of education programs should not be on risk perceptions, but on decreasing positive attitudes towards alcohol in traffic and increasing sense of responsibility instead. Cognitions regarding near accidents should be studied, the role of safe cycling self-efficacy is unclear.

  1. Mediating Business

    DEFF Research Database (Denmark)

    "Mediating Business" is a study of the expansion of business journalism. Building on evidence from Denmark, Finland, Norway and Sweden, "Mediating Business" is a comparative and multidisciplinary study of one of the major transformations of the mass media and the realm of business - nationally...... and globally. The book explores the history of key innovations and innovators in the business press. It analyzes changes in the discourse of business journalism associated with the growth in business news and the development of new ways of framing business issues and events. Finally, it examines...... the organizational implications of the increased media visibility of business and, in particular, the development of corporate governance and media relations....

  2. Regular Motions of Resonant Asteroids

    Science.gov (United States)

    Ferraz-Mello, S.

    1990-11-01

    RESUMEN. Se revisan resultados analiticos relativos a soluciones regulares del problema asteroidal eliptico promediados en la vecindad de una resonancia con jupiten Mencionamos Ia ley de estructura para libradores de alta excentricidad, la estabilidad de los centros de liberaci6n, las perturbaciones forzadas por la excentricidad de jupiter y las 6rbitas de corotaci6n. ABSTRAC This paper reviews analytical results concerning the regular solutions of the elliptic asteroidal problem averaged in the neighbourhood of a resonance with jupiter. We mention the law of structure for high-eccentricity librators, the stability of the libration centers, the perturbations forced by the eccentricity ofjupiter and the corotation orbits. Key words: ASThROIDS

  3. Families classification including multiopposition asteroids

    Science.gov (United States)

    Milani, Andrea; Spoto, Federica; Knežević, Zoran; Novaković, Bojan; Tsirvoulis, Georgios

    2016-01-01

    In this paper we present the results of our new classification of asteroid families, upgraded by using catalog with > 500,000 asteroids. We discuss the outcome of the most recent update of the family list and of their membership. We found enough evidence to perform 9 mergers of the previously independent families. By introducing an improved method of estimation of the expected family growth in the less populous regions (e.g. at high inclination) we were able to reliably decide on rejection of one tiny group as a probable statistical fluke. Thus we reduced our current list to 115 families. We also present newly determined ages for 6 families, including complex 135 and 221, improving also our understanding of the dynamical vs. collisional families relationship. We conclude with some recommendations for the future work and for the family name problem.

  4. Colorimetry and magnitudes of asteroids

    Science.gov (United States)

    Bowell, E.; Lumme, K.

    1979-01-01

    In the present paper, 1500 UBV observations are analyzed by a new rather general multiple scattering theory which provided clear insight into previously poorly-recognized optical nature of asteroid surfaces. Thus, phase curves are shown to consist of a surface-texture controlled component, due to singly scattered light, and a component due to multiple scattering. Phase curve shapes can be characterized by a single parameter, the multiple scattering factor, Q. As Q increases, the relative importance of the opposition effect diminishes. Asteroid surfaces are particulate and strikingly similar to texture, being moderately porous and moderately rough on a scale greater than the wavelength of light. In concequence, Q (and also the phase coefficient) correlate well with geometric albedo, and there exists a purely photometric means of determining albedos and diameters.

  5. Comets and Asteroids with FIRST

    Science.gov (United States)

    Bockelée-Morvan, D.; Crovisier, J.

    2001-07-01

    The infrared and microwave domains have proved to be privileged tools to study the physical and chemical properties of small bodies of the Solar System. After a review of the recent results obtained on comets and asteroids in these wavelength ranges, we forecast the major outcomes that can be expected from their observations with the Herschel Space Observatory (hereafter referred as to FIRST, the former denomination). This prospect is focussed on: 1) observations of water rotational lines in comets to measure water outgassing and study water excitation in the coma and its kinematics; 2) observations of HDO in comets to constrain solar nebula models and formation scenarii of comets; 3) the study of surface properties of asteroids.

  6. A method to determine asteroid poles

    Science.gov (United States)

    Deangelis, G.

    1993-01-01

    The determination of spin axis and shape is well known to be of fundamental importance for studies about the rotational and physical properties of asteroids. In particular, knowledge that the pole coordinate distribution is random or not could indicate the probable non-Maxwellian distribution of asteroid spin axes, while the distribution in terms of size and shape could place important constraints on the theories about the collisional history of some individual asteroids, of asteroid families, and of the asteroid population as a whole. Many kinds of methods have been developed to determine pole coordinates. An EA method is presented, from which it is possible to obtain the solution with no trial poles, but with a simultaneous least square fit on both the E and A part. Results for rotational and shape parameters were obtained for 18 asteroids: the values of the obtained parameters are generally in close agreement with those of others.

  7. Selecting asteroids for a targeted spectroscopic survey

    CERN Document Server

    Oszkiewicz, D A; Tomov, T; Birlan, M; Geier, S; Penttilä, A; Polińska, M

    2014-01-01

    Asteroid spectroscopy reflects surface mineralogy. There are few thousand asteroids whose surfaces have been observed spectrally. Determining the surface properties of those objects is important for many practical and scientific applications, such as for example developing impact deflection strategies or studying history and evolution of the Solar System and planet formation. The aim of this study is to develop a pre-selection method that can be utilized in searching for asteroids of any taxonomic complex. The method could then be utilized im multiple applications such as searching for the missing V-types or looking for primitive asteroids. We used the Bayes Naive Classifier combined with observations obtained in the course of the Sloan Digital Sky Survey and the Wide-field Infrared Survey Explorer surveys as well as a database of asteroid phase curves for asteroids with known taxonomic type. Using the new classification method we have selected a number of possible V-type candidates. Some of the candidates we...

  8. Eccentricity distribution in the main asteroid belt

    CERN Document Server

    Malhotra, Renu

    2016-01-01

    The observationally complete sample of the main belt asteroids now spans more than two orders of magnitude in size and numbers more than 64,000 (excluding collisional family members). We undertook an analysis of asteroids' eccentricities and their interpretation with simple physical models. We find that Plummer's (1916) conclusion that the asteroids' eccentricities follow a Rayleigh distribution holds for the osculating eccentricities of large asteroids, but the proper eccentricities deviate from a Rayleigh distribution: there is a deficit of eccentricities smaller than $\\sim0.1$ and an excess of larger eccentricities. We further find that the proper eccentricities do not depend significantly on asteroid size but have strong dependence on heliocentric distance: the outer asteroid belt follows a Rayleigh distribution, but the inner belt is strikingly different. Eccentricities in the inner belt can be modeled as a vector sum of a primordial eccentricity vector of random orientation and magnitude drawn from a Ra...

  9. Mining the Apollo and Amor asteroids

    Science.gov (United States)

    Oleary, B.

    1977-01-01

    Earth-approaching asteroids could provide raw materials for space manufacturing. For certain asteroids the total energy per unit mass for the transfer of asteroidal resources to a manufacturing site in high earth orbit is comparable to that for lunar materials. For logistical reasons the cost may be many times less. Optical studies suggest that these asteroids have compositions corresponding to those of carbonaceous and ordinary chondrites, with some containing large quantities of iron and nickel; other are thought to contain carbon, nitrogen, and hydrogen, elements that appear to be lacking on the moon. The prospect that several new candidate asteroids will be discovered over the next few years increases the likelihood that a variety of asteroidal resource materials can be retrieved on low-energy missions.

  10. Asteroids prospective energy and material resources

    CERN Document Server

    2013-01-01

    The Earth has limited material and energy resources while these resources in space are virtually unlimited. Further development of humanity will require going beyond our planet and exploring of extraterrestrial resources and sources of unlimited power.   Thus far, all missions to asteroids have been motivated by scientific exploration. However, given recent advancements in various space technologies, mining asteroids for resources is becoming ever more feasible. A significant portion of asteroids value is derived from their location; the required resources do not need to be lifted at a great expense from the surface of the Earth.   Resources derived from Asteroid not only can be brought back to Earth but could also be used to sustain human exploration of space and permanent settlements in space.   This book investigates asteroids' prospective energy and material resources. It is a collection of topics related to asteroid exploration, and utilization. It presents past and future technologies and solutions t...

  11. Exospheres from Asteroids to Planets

    Science.gov (United States)

    Killen, Rosemary M.; Burger, Matthew H.; Farrell, William M.; DREAM2

    2016-10-01

    The study of exospheres can help us understand the long-term loss of volatiles from planetary bodies due to interactions of planets, satellites, and small bodies with the interplanetary medium (solar wind, meteors, and dust), solar radiation, internal forces including diffusion and outgassing, and surface effects like sticking and chemistry. Recent evidence for water and OH on the moon has spurred interest in processes involving chemistry and sequestration of volatile species at the poles and in voids. In recent years, NASA has sent spacecraft to asteroids including Vesta and Ceres, and ESA sent Rosetta to the asteroids Lutetia and Steins. OSIRIS-REX will return a sample from a primitive asteroid, Bennu, to Earth. It is possible that a Phobos-Deimos flyby will be a precursor to a manned mission to Mars. Exospheric particles are derived from the surface and to some extent from interplanetary dust and meteoroids. By comparing the exospheric compositions before and after major meteor shower events it may be possible to determine the extent to which the exosphere reflects the surface composition. Observation of an escaping exosphere, termed a corona, is challenging. We therefore have embarked on a parametrical study of exospheres as a function of basic controlling parameters such as the mass of the primary object, mass of the exospheric species, heliocentric distance, rotation rate of the primary, composition of the body (asteroid type or icy body). These parameters will be useful for mission planning as well as quick look data to determine the size and location of bodies likely to retain their exospheres and observability of exospheric species. We will also consider the sizes of small clusters that may be gravitationally bound to small bodies such as Phobos. In addition, it is of interest to be able to determine the extent of contamination of the pristine exosphere due to the spacecraft sent to make measurements, and the effect on the measurements of outgassing in the

  12. Recovering and Mining Asteroids with a Gas-Sealed Enclosure

    Science.gov (United States)

    Jenniskens, P.; Damer, B.; Norkus, R.; Pilotz, S.; Grigsby, B.; Adams, C.; Blair, B. R.

    2015-01-01

    The internal structure of weakly consolidated rubble piles and primitive asteroids can be studied closer to home, and such asteroids can be mined, if it is possible to create a gas-sealed enclosure around the asteroid.

  13. Storyboard GALILEO CRUISE SCIENCE OPPORTUNITIES describes asteroid encounters

    Science.gov (United States)

    1989-01-01

    Storyboard with mosaicked image of an asteroid and entitled GALILEO CRUISE SCIENCE OPPORTUNITIES describes asteroid objectives. These objectives include: first asteroid encounter; surface geology, composition size, shape, mass; and relation of primitive bodies to meteorites.

  14. Anchoring a lander on an asteroid using foam stabilization Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA has proposed several missions to land a craft on an asteroid and potentially to return samples from it. While large asteroids in the asteroid belt can exhibit a...

  15. Stabilities of asteroid orbits in resonances

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A map of the asteroid motion is studied carefully. An exponential diffusion law in the chaotic sea and an algebraic law in the mixed region are observed. The effects of perturbations on diffusion are also discussed. The fixed points, their stabilities and the diffusion properties of the map give qualitative explanations of the distribution of asteroids, i.e. the depletion and accumulation of asteroids in the outer main belt, particularly in the first order mean motion resonances with Jupiter.

  16. Asteroid families, dynamics and astrometry

    Science.gov (United States)

    Williams, J. G.; Gibson, J.

    1987-01-01

    The proper elements and family assignments for the 1227 Palomar-Leiden Survey asteroids of high quality were tabulated. In addition to the large table, there are also auxiliary tables of Mars crossers and commensurate objects, histograms of the proper element distributions, and a discussion. Probably the most important part of the discussion describes the Mars crossing boundary, how the closest distances of approach to Mars and Jupiter are calculated, and why the observed population of Mars crossers should bombard that planet episodically rather than uniformly. Analytical work was done to derive velocity distributions of family forming events from proper element distributions subject to assumptions which may be appropriate for cratering events. Software was developed for a microcomputer to permit plotting of the proper elements. Three orthogonal views are generated and stereo pairs can be printed when desired. This program was created for the study of asteroid families. The astrometry task is directed toward measuring and reducing positions on faint comets and the minor planets with less common orbits. The observational material is CCD frames taken with the Palomar 1.5 m telescope. Positions of 10 comets and 16 different asteroids were published on the Minor Planet Circulars.

  17. Near Earth Asteroid (NEA) Scout

    Science.gov (United States)

    Johnson, Les; Castillo-Rogez, Julie; Dervan, Jared; McNutt, Leslie

    2017-01-01

    NASA is developing solar sail propulsion for a near-term Near Earth Asteroid (NEA) reconnaissance mission that will lay the groundwork for the future use of solar sails. The NEA Scout mission will use the sail as primary propulsion allowing it to survey and image one NEA's of interest for future human exploration. NEA Scout will launch on the first mission of the Space Launch System (SLS) in 2018. After its first encounter with the Moon, NEA Scout will enter the sail characterization phase by the 86 square meter sail deployment. A mechanical Active Mass Translation (AMT) system, combined with the remaining ACS propellant, will be used for sail momentum management. The spacecraft will perform a series of lunar flybys to achieve optimum departure trajectory before beginning its two year-long cruise. About one month before the asteroid flyby, NEA Scout will start its approach phase using optical navigation on top of radio tracking. The solar sail will provide NEA Scout continuous low thrust to enable a relatively slow flyby of the target asteroid under lighting conditions favorable to geological imaging. Once complete, NASA will have demonstrated the capability to fly low-cost, high delta V CubeSats to perform interplanetary missions.

  18. Risky Driving Behaviours among Medical Students in Erbil, Iraq

    Directory of Open Access Journals (Sweden)

    Nazar P. Shabila

    2015-08-01

    Full Text Available Objectives: This study aimed to assess risky driving behaviours among medical students in Erbil, Iraq, and to explore the relationship between risky driving behaviours and perceptions of risky driving. Methods: This self-administered questionnaire-based survey was conducted from January to May 2014 among a random sample of 400 medical students at Hawler Medical University in Erbil. The questionnaire was designed to assess the frequency of engagement in 21 risky driving behaviours, the perceived risk of each behaviour and the preference for each behaviour as ranked on a 5-point scale. Results: A total of 386 students responded to the survey (response rate: 96.5%. Of these, 211 reported that they currently drove a vehicle (54.7%. Drivers most frequently engaged in the following behaviours: playing loud music (35.9%, speeding (30.4%, allowing front seat passengers to not wear seat belts (27.9% and using mobile phones (27.7%. Least frequent driving behaviours included not stopping at a red light (3.9%, driving while sleepy (4.4%, driving after a mild to moderate intake of alcohol (4.5% and drunk driving (6.4%. Mean risky driving behaviour scores were significantly higher among males (P 20-year-olds (P = 0.028. There was a significant positive relationship between the preference for risky behaviours and risky driving behaviours (beta = 0.44; P <0.001. Conclusion: Medical students in Erbil reported high frequencies of several serious risky driving behaviours. The preference for risky behaviours was found to be an important predictor of risky driving behaviours among medical students in Erbil.

  19. Geotechnical Tests on Asteroid Simulant Orgueil

    Science.gov (United States)

    Garcia, Alexander D'marco

    2017-01-01

    In the last 100 years, the global population has more than quadrupled to over seven billion people. At the same time, the demand for food and standard of living has been increasing which has amplified the global water use by nearly eight times from approximately 500 to 4000 cu km per yr from 1900 to 2010. With the increasing concern to sustain the growing population on Earth it is necessary to seek other approaches to ensure that our planet will have resources for generations to come. In recent years, the advancement of space travel and technology has allowed the idea of mining asteroids with resources closer to becoming a reality. During the duration of the internship at NASA Kennedy Space Center, several geotechnical tests were conducted on BP-1 lunar simulant and asteroid simulant Orgueil. The tests that were conducted on BP-1 was to practice utilizing the equipment that will be used on the asteroid simulant and the data from those tests will be omitted from report. Understanding the soil mechanics of asteroid simulant Orgueil will help provide basis for future technological advances and prepare scientists for the conditions they may encounter when mining asteroids becomes reality in the distant future. Distinct tests were conducted to determine grain size distribution, unconsolidated density, and maximum density. Once the basic properties are known, the asteroid simulant will be altered to different levels of compaction using a vibrator table to see how compaction affects the density. After different intervals of vibration compaction, a miniature vane shear test will be conducted. Laboratory vane shear testing is a reliable tool to investigate strength anisotropy in the vertical and horizontal directions of a very soft to stiff saturated fine-grained clayey soil. This test will provide us with a rapid determination of the shear strength on the undisturbed compacted regolith. The results of these tests will shed light on how much torque is necessary to drill

  20. The World of WarsRisky systems

    DEFF Research Database (Denmark)

    Harste, Gorm

      The world of the future will not be one without wars. The many hopes we have about a future peace governed by a more or less confederal state will not make wars obsolete. Regular wars and irregular wars will continue and probably on different subjects than we are used to. The paper proposes...... that the form of war will be more about temporalities, i.e. fast interchanges or, rather, more risky protracted wars of attrition and exhaustion and less on tactical well defined territories. The West can neither dominate such wars nor establish one world that is ruled or even governed. The risk is that we have...... the systems we have. They have their own path dependencies, their temporal bindings and their own stories to tell. In the worst case, they stick to an imaginary of almighty power - and then they lose. We tend to forget that our present past will be experienced and told differently in the future past...

  1. The Neuropsychology of Risky Sexual Behavior

    Science.gov (United States)

    Ross, J. Megan; Duperrouzel, Jacqueline; Vega, Melanie; Gonzalez, Raul

    2017-01-01

    Objective Engagement in risky sexual behavior (RSB) is a significant public health concern. A growing body of literature is elucidating the role of brain systems and neuropsychological constructs implicated in RSB, which may pave the way for novel insights and prevention efforts. Methods In this article, we review studies incorporating neuropsychology into the study of RSB across the lifespan. The review of the literature on the neuropsychology of RSB is separated into three different sections by age of participants. Background is presented on research associating RSB with neurocognitive processes and the brain systems involved. Given the overlap between RSBs and substance use, studies addressing these problems in tandem are also discussed. Results Neurocognitive constructs are implicated in RSB, including impulsivity, decision-making, and working memory. Discussion Thus far, evidence suggest that neuropsychological factors are associated with engagement in RSB. More research on the influence of neuropsychological factors on engagement in RSB is necessary and may help inform future prevention efforts. PMID:27173086

  2. How Risky Are Recessions for Top Earners?

    OpenAIRE

    Fatih Guvenen; Greg Kaplan; Jae Song

    2014-01-01

    How sensitive are the earnings of top earners to business cycles? And, how does the business cycle sensitivity of top earners vary by industry? We use a confidential dataset on earnings histories of US males from the Social Security Administration. On average, individuals in the top 1% of the earnings distribution are slightly more cyclical than the population average. But there are large differences across sectors: Top earners in Finance, Insurance, and Real Estate (FIRE) and Construction fa...

  3. Eccentricity distribution in the main asteroid belt

    Science.gov (United States)

    Malhotra, Renu; Wang, Xianyu

    2017-03-01

    The observationally complete sample of the main belt asteroids now spans more than two orders of magnitude in size and numbers more than 64 000 (excluding collisional family members). We undertook an analysis of asteroids' eccentricities and their interpretation with simple physical models. We find that a century old conclusion that the asteroids' eccentricities follow a Rayleigh distribution holds for the osculating eccentricities of large asteroids, but the proper eccentricities deviate from a Rayleigh distribution; there is a deficit of eccentricities smaller than ∼0.1 and an excess of larger eccentricities. We further find that the proper eccentricities do not depend significantly on asteroid size but have strong dependence on heliocentric distance; the outer asteroid belt follows a Rayleigh distribution, but the inner belt is strikingly different. Eccentricities in the inner belt can be modelled as a vector sum of a primordial eccentricity vector of random orientation and magnitude drawn from a Rayleigh distribution of parameter ∼0.06, and an excitation of random phase and magnitude ∼0.13. These results imply that when a late dynamical excitation of the asteroids occurred, it was independent of asteroid size and was stronger in the inner belt than in the outer belt. We discuss implications for the primordial asteroid belt and suggest that the observationally complete sample size of main belt asteroids is large enough that more sophisticated model-fitting of the eccentricities is warranted and could serve to test alternative theoretical models of the dynamical excitation history of asteroids and its links to the migration history of the giant planets.

  4. Gender Differences in the Factors Explaining Risky Behavior Online.

    Science.gov (United States)

    Sasson, Hagit; Mesch, Gustavo

    2016-05-01

    In searching for the social and cognitive antecedents of risky online behaviors, some studies have relied on the theory of planned behavior. According to the theory, three components serve as predictors of a given behavior-attitudes toward the behavior (beliefs that people hold about a given behavior), subjective norms (perceptions of what significant others think about the behavior) and perceived behavior control (perceptions about the ease or difficulty of engaging in a particular behavior). However, none of these studies considered the possibility that these factors work differently for boys and girls. We constructed models of the possible antecedents (attitudes, subjective norms and perceived behavior control) of risky behavior online and tested them using a representative sample of 495 sixth to eleventh grade students (46 % female) in a large city in Israel. We measured risky behavior online with items indicating the frequency of posting personal details, sending an insulting message and meeting face-to-face with a stranger met online. Structural equation modeling revealed that peers' subjective norms (beliefs that friends approve of engaging in risky online behaviors), parents' subjective norms (beliefs that parents accept involvement in risky online behaviors) and perceived behavior control were related to boys' risky behavior online, whereas for girls, only parents' subjective norms had such an association. Expanding the models to include other factors underscored that family factors were most strongly associated with girls' risky behavior online.

  5. Socioeconomic disadvantage and indicators of risky alcohol-drinking patterns.

    Science.gov (United States)

    Paljärvi, Tapio; Suominen, Sakari; Car, Josip; Koskenvuo, Markku

    2013-01-01

    The purpose was to establish how the association between socioeconomic disadvantage and risky drinking depends on the indicator of risky alcohol-drinking patterns. Alcohol-drinking Finnish men (n = 9316) and women (n = 11,888) aged 20-54 years at baseline participated in the Health and Social Support (HeSSup) postal survey in 1998. Socioeconomic disadvantage was measured by low educational level, history of previous unemployment among those currently employed, current unemployment, being on disability pension and history of experiencing financial hardships. Indicators of risky drinking were hazardous weekly intake (≥24 and ≥16 Finnish standard drinks for men and women, respectively), frequency of intoxications/drunkenness, hangovers and alcohol-induced pass-outs. The study participants were also followed up for 7 years for alcohol-specific hospitalizations and deaths. Socioeconomic gradient in risky drinking was observed across all indicators of risky drinking, but the gradient was relatively larger in patterns of risky drinking representing high-intensity drinking occasions such as alcohol-induced hangovers and pass-outs. No marked gender differences were observed. These results highlight the need to take into account the multidimensionality of risky alcohol-drinking patterns as a contributing factor in the socioeconomic gradient in alcohol use.

  6. Spitzer Survey of the Karin Cluster Asteroids

    NARCIS (Netherlands)

    Harris, Alan W.; Mueller, M.; Lisse, C.; Cheng, A.; Osip, D.

    2007-01-01

    The Karin cluster is one of the youngest known families of main-belt asteroids, dating back to a collisional event only 5.8 Myr ago. Using the Spitzer Space Telescope we have sampled the thermal continua of 17 Karin cluster asteroids, down to the smallest members discovered so far, in order to deriv

  7. The Steward Observatory asteroid relational database

    Science.gov (United States)

    Sykes, Mark V.; Alvarezdelcastillo, Elizabeth M.

    1992-01-01

    The Steward Observatory Asteroid Relational Database (SOARD) was created as a flexible tool for undertaking studies of asteroid populations and sub-populations, to probe the biases intrinsic to asteroid databases, to ascertain the completeness of data pertaining to specific problems, to aid in the development of observational programs, and to develop pedagogical materials. To date SOARD has compiled an extensive list of data available on asteroids and made it accessible through a single menu-driven database program. Users may obtain tailored lists of asteroid properties for any subset of asteroids or output files which are suitable for plotting spectral data on individual asteroids. A browse capability allows the user to explore the contents of any data file. SOARD offers, also, an asteroid bibliography containing about 13,000 references. The program has online help as well as user and programmer documentation manuals. SOARD continues to provide data to fulfill requests by members of the astronomical community and will continue to grow as data is added to the database and new features are added to the program.

  8. Spitzer Survey of the Karin Cluster Asteroids

    NARCIS (Netherlands)

    Harris, Alan W.; Mueller, M.; Lisse, C.; Cheng, A.; Osip, D.

    2007-01-01

    The Karin cluster is one of the youngest known families of main-belt asteroids, dating back to a collisional event only 5.8 Myr ago. Using the Spitzer Space Telescope we have sampled the thermal continua of 17 Karin cluster asteroids, down to the smallest members discovered so far, in order to

  9. [Asteroid hyalopathy (benson's disease): about a case].

    Science.gov (United States)

    Bienvenu, Yogolelo Asani; Angel, Musau Nkola; Leon, Kabamba Ngombe; Socrate, Kapalu Mwangala; Bruno, Iye Ombamba Kayimba; Gaby, Chenge Borasisi

    2017-01-01

    We here report a case of a 58 year-old diabetic male patient with asteroid hyalopathy, an affection rarely described in the literature. This study can help focus the attention of scientists on the pathologies of the vitreous disorders in diabetic patients as well as on other systemic diseases asteroid hyalopathy may be associated with.

  10. Periodic Motion near the Surface of Asteroids

    CERN Document Server

    Jiang, Yu; Li, Hengnian

    2015-01-01

    We are interested in the periodic motion and bifurcations near the surface of an asteroid. The gravity field of an irregular asteroid and the equation of motion of a particle near the surface of an asteroid are studied. The periodic motions around the major body of triple asteroid 216 Kleopatra and the OSIRIS REx mission target asteroid 101955 Bennu are discussed. We find that motion near the surface of an irregular asteroid is quite different from the motion near the surface of a homoplastically spheroidal celestial body. The periodic motions around the asteroid 101955 Bennu and 216 Kleopatra indicate that the geometrical shapes of the orbits are probably very sophisticated. There exist both stable periodic motions and unstable periodic motions near the surface of the same irregular asteroid. This periodic motion which is unstable can be resonant or non resonant. The period doubling bifurcation and pseudo period doubling bifurcation of periodic orbits coexist in the same gravity field of the primary of the t...

  11. Origin of igneous meteorites and differentiated asteroids

    Science.gov (United States)

    Scott, E.; Goldstein, J.; Asphaug, E.; Bottke, W.; Moskovitz, N.; Keil, K.

    2014-07-01

    Introduction: Igneously formed meteorites and asteroids provide major challenges to our understanding of the formation and evolution of the asteroid belt. The numbers and types of differentiated meteorites and non-chondritic asteroids appear to be incompatible with an origin by fragmentation of numerous Vesta-like bodies by hypervelocity impacts in the asteroid belt over 4 Gyr. We lack asteroids and achondrites from the olivine-rich mantles of the parent bodies of the 12 groups of iron meteorites and the ˜70 ungrouped irons, the 2 groups of pallasites and the 4--6 ungrouped pallasites. We lack mantle and core samples from the parent asteroids of the basaltic achondrites that do not come from Vesta, viz., angrites and the ungrouped eucrites like NWA 011 and Ibitira. How could core samples have been extracted from numerous differentiated bodies when Vesta's basaltic crust was preserved? Where is the missing Psyche family of differentiated asteroids including the complementary mantle and crustal asteroids [1]? Why are meteorites derived from far more differentiated parent bodies than chondritic parent bodies even though C and S class chondritic asteroids dominate the asteroid belt? New paradigm. Our studies of meteorites, impact modeling, and dynamical studies suggest a new paradigm in which differentiated asteroids accreted at 1--2 au less than 2 Myr after CAI formation [2]. They were rapidly melted by 26Al and disrupted by hit-and-run impacts [3] while still molten or semi-molten when planetary embryos were accreting. Metallic Fe-Ni bodies derived from core material cooled rapidly with little or no silicate insulation less than 4 Myr after CAI formation [4]. Fragments of differentiated planetesimals were subsequently tossed into the asteroid belt. Meteorite evidence for early disruption of differentiated asteroids. If iron meteorites were samples of Fe-Ni cores of bodies that cooled slowly inside silicate mantles over ˜50--100 Myr, irons from each core would have

  12. The Compositional Structure of the Asteroid Belt

    CERN Document Server

    DeMeo, Francesca E; Walsh, Kevin J; Chapman, Clark R; Binzel, Richard P

    2015-01-01

    The past decade has brought major improvements in large-scale asteroid discovery and characterization with over half a million known asteroids and over 100,000 with some measurement of physical characterization. This explosion of data has allowed us to create a new global picture of the Main Asteroid Belt. Put in context with meteorite measurements and dynamical models, a new and more complete picture of Solar System evolution has emerged. The question has changed from "What was the original compositional gradient of the Asteroid Belt?" to "What was the original compositional gradient of small bodies across the entire Solar System?" No longer is the leading theory that two belts of planetesimals are primordial, but instead those belts were formed and sculpted through evolutionary processes after Solar System formation. This article reviews the advancements on the fronts of asteroid compositional characterization, meteorite measurements, and dynamical theories in the context of the heliocentric distribution of...

  13. Measurement of Cohesion in Asteroid Regolith Materials

    Science.gov (United States)

    Kleinhenz, Julie; Gaier, James; Waters, Deborah; Harvey, Ralph; Zeszut, Zoe; Carreno, Brandon; Shober, Patrick

    2017-01-01

    There is increasing evidence that a large fraction of asteroids, and even Phobos, have such low densities (asteroids are thought to be made up of unconsolidated smaller particles of varying size referred to as rubble piles. Images of the asteroid Itokawa reinforce this hypothesis. What holds the rubble piles together? Gravitational forces alone are not strong enough to hold together rubble pile asteroids, at least not those that are rapidly spinning Van der Waals forces and or Electrostatic forces must therefore be responsible for holding them together. Previous work suggests that electrostatic forces, which are orders of magnitude stronger are far more likely. Charge build-up is a likely consequence of the interaction of airless bodies with the solar wind plasma, analogous to what has been proposed to occur on the moon. Objective: Experimentally measure cohesive forces relevant to those holding rubble pile asteroids together

  14. Business intelligence

    Directory of Open Access Journals (Sweden)

    Cebotarean Elena

    2011-02-01

    Full Text Available Business intelligence (BI refers to computer-based techniques used in spotting, digging-out, and analyzing business data, such as sales revenue by products and/or departments, or by associated costs and incomes. BI technologies provide historical, current, and predictive views of business operations. Common functions of business intelligence technologies are reporting, online analytical processing, analytics, data mining, business performance management, benchmarking, text mining, and predictive analytics. Business intelligence aims to support better business decision-making. Thus a BI system can be called a decision support system (DSS. Though the term business intelligence is sometimes used as a synonym for competitive intelligence, because they both support decision making, BI uses technologies, processes, and applications to analyze mostly internal, structured data and business processes while competitive intelligence gathers, analyzes and disseminates information with a topical focus on company competitors. Business intelligence understood broadly can include the subset of competitive intelligence.

  15. Asteroid spin-up fission systems

    Science.gov (United States)

    Pravec, P.

    2014-07-01

    Among asteroids smaller than about 15 km in diameter, there is a population of binary and multiple asteroid systems that show characteristics strongly suggesting their formation by spin-up fission. I will review the current observational data we have on the systems and compare them with predictions from theories of formation of asteroid systems. I will show that the best explanation of their observed properties is provided by the theory of fission of cohesionless (rubble-pile) asteroids spun up to the critical spin frequency by the YORP effect. Observed asteroid systems are of two kinds: bound and unbound. Bound asteroid systems typically consist of a larger primary and one or two smaller satellites. Unbound systems consist of two asteroids orbiting the Sun on highly similar orbits, again with one being typically larger (primary) and the other being smaller (secondary). These two groups are not exclusive; there exist systems with one or two bound and an unbound secondary. Our current sample consists of 133 bound asteroid systems (binaries or triples) with primary sizes between 0.12 and 13 km and of 178 asteroid pairs with similar primary sizes. Bound systems have been observed in heliocentric orbits from near the Earth to the outer main belt, while asteroid pairs are recognizable only in the main belt where their orbits are only slowly dispersed so the pairs can be identified for up to 2 Myr after formation. The leading observational techniques for discovery and characterization of asteroid systems are radar imagery (for near-Earth asteroid systems) and lightcurve photometry (for main-belt ones). The observed characteristics of asteroid systems suggesting their formation by rotational fission of parent rubble-pile asteroids after being spun up by the YORP effect are as follows. The angular momentum content of binary asteroids is close to critical. The orientations of satellite orbits are non-random; the orbital poles concentrate near the obliquities of 0 and 180

  16. Alcohol Can Be a Risky Guest At Holiday Parties

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_162488.html Alcohol Can Be a Risky Guest at Holiday Parties ... a part of the festivities. Unfortunately, so are alcohol-related accidents and deaths. Many people who attend ...

  17. Using Malaria Medication for Leg Cramps Is Risky

    Science.gov (United States)

    ... Products Vaccines, Blood & Biologics Articulos en Espanol Using Malaria Medication for Leg Cramps is Risky Printer-friendly ... approved only to treat a certain type of malaria (uncomplicated malaria) caused by the parasite Plasmodium falciparum. ...

  18. Meds May Curb Risky Behaviors for Kids with ADHD

    Science.gov (United States)

    ... Meds May Curb Risky Behaviors for Kids With ADHD Study found drug abuse, STDs and injuries were ... Despite concerns that the stimulants used to treat attention-deficit/hyperactivity disorder (ADHD) might raise the risk of drug abuse, ...

  19. Risky Drinking Can Put a Chill on Your Summer Fun

    Science.gov (United States)

    ... on Your Summer Fun Print version Risky Drinking Can Put a Chill on Your Summer Fun Summer ... adults involve the use of alcohol. 1 Swimmers can get in over their heads. Alcohol impairs judgment ...

  20. A comparison of risky sexual behaviours between circumcised and ...

    African Journals Online (AJOL)

    Keywords: Risky sexual behaviours, circumcised, uncircumcised men, 30-44 years, Botswana. ... male circumcision in the countries in this region2. As a result, many .... whether there are any preventive measures against HIV infection.

  1. Reconstructing HST Images of Asteroids

    Science.gov (United States)

    Storrs, A. D.; Bank, S.; Gerhardt, H.; Makhoul, K.

    2003-12-01

    We present reconstructions of images of 22 large main belt asteroids that were observed by Hubble Space Telescope with the Wide-Field/Planetary cameras. All images were restored with the MISTRAL program (Mugnier, Fusco, and Conan 2003) at enhanced spatial resolution. This is possible thanks to the well-studied and stable point spread function (PSF) on HST. We present some modeling of this process and determine that the Strehl ratio for WF/PC (aberrated) images can be improved to 130 ratio of 80 We will report sizes, shapes, and albedos for these objects, as well as any surface features. Images taken with the WFPC-2 instrument were made in a variety of filters so that it should be possible to investigate changes in mineralogy across the surface of the larger asteroids in a manner similar to that done on 4 Vesta by Binzel et al. (1997). Of particular interest are a possible water of hydration feature on 1 Ceres, and the non-observation of a constriction or gap between the components of 216 Kleopatra. Reduction of this data was aided by grant HST-GO-08583.08A from the Space Telescope Science Institute. References: Mugnier, L.M., T. Fusco, and J.-M. Conan, 2003. JOSA A (submitted) Binzel, R.P., Gaffey, M.J., Thomas, P.C., Zellner, B.H., Storrs, A.D., and Wells, E.N. 1997. Icarus 128 pp. 95-103

  2. Risky Arbitrage Strategies: Optimal Portfolio Choice and Economic Implications

    OpenAIRE

    Liu, Jun; Timmermann, Allan G

    2009-01-01

    We define risky arbitrages as self-financing trading strategies that have a strictly positive market price but a zero expected cumulative payoff. A continuous time cointegrated system is used to model risky arbitrages as arising from a mean-reverting mispricing component. We derive the optimal trading strategy in closed-form and show that the standard textbook arbitrage strategy is not optimal. In a calibration exercise, we show that the optimal strategy makes a sizeable difference in economi...

  3. Olivine-dominated Asteroids: Mineralogy and Origin

    CERN Document Server

    Sanchez, Juan A; Kelley, Michael S; Cloutis, Edward A; Bottke, William F; Nesvorný, David; Lucas, Michael P; Hardersen, Paul S; Gaffey, Michael J; Abell, Paul A; Corre, Lucille Le

    2013-01-01

    Olivine-dominated asteroids are a rare type of objects formed either in nebular processes or through magmatic differentiation. The analysis of meteorite samples suggest that at least 100 parent bodies in the main belt experienced partial or complete melting and differentiation before being disrupted. However, only a few olivine-dominated asteroids, representative of the mantle of disrupted differentiated bodies, are known to exist. Due to the paucity of these objects in the main belt their origin and evolution have been a matter of great debate over the years. In this work we present a detailed mineralogical analysis of twelve olivine-dominated asteroids. Within our sample we distinguish two classes, one that we call pure-olivine asteroids and another referred to as olivine-rich asteroids. For the pure-olivine asteroids the olivine chemistry was found to range from ~ Fo49 to Fo70, consistent with the values measured for brachinites and R chondrites. In the case of the olivine-rich asteroids we determined thei...

  4. Rotational Study of Ambiguous Taxonomic Classified Asteroids

    Science.gov (United States)

    Linder, Tyler R.; Sanchez, Rick; Wuerker, Wolfgang; Clayson, Timothy; Giles, Tucker

    2017-01-01

    The Sloan Digital Sky Survey (SDSS) moving object catalog (MOC4) provided the largest ever catalog of asteroid spectrophotometry observations. Carvano et al. (2010), while analyzing MOC4, discovered that individual observations of asteroids which were observed multiple times did not classify into the same photometric-based taxonomic class. A small subset of those asteroids were classified as having both the presence and absence of a 1um silicate absorption feature. If these variations are linked to differences in surface mineralogy, the prevailing assumption that an asteroid’s surface composition is predominantly homogenous would need to be reexamined. Furthermore, our understanding of the evolution of the asteroid belt, as well as the linkage between certain asteroids and meteorite types may need to be modified.This research is an investigation to determine the rotational rates of these taxonomically ambiguous asteroids. Initial questions to be answered:Do these asteroids have unique or nonstandard rotational rates?Is there any evidence in their light curve to suggest an abnormality?Observations were taken using PROMPT6 a 0.41-m telescope apart of the SKYNET network at Cerro Tololo Inter-American Observatory (CTIO). Observations were calibrated and analyzed using Canopus software. Initial results will be presented at AAS.

  5. Target Asteroids! Observing Campaigns for April through June 2017

    Science.gov (United States)

    Hergenrother, Carl; Hill, Dolores

    2017-04-01

    Asteroid campaigns to be conducted by the Target Asteroids! program during the April-June 2017 quarter are described. In addition to asteroids on the original Target Asteroids! list of easily accessible spacecraft targets, an effort has been made to identify other asteroids that are 1) brighter and easier to observe for small telescope users and 2) analogous to (101955) Bennu and (162173) Ryugu, targets of the OSIRIS-REx and Hayabusa-2 sample return missions.

  6. Dynamics of rotationally fissioned asteroids: Source of observed small asteroid systems

    CERN Document Server

    Jacobson, Seth A

    2014-01-01

    We present a model of near-Earth asteroid (NEA) rotational fission and ensuing dynamics that describes the creation of synchronous binaries and all other observed NEA systems including: doubly synchronous binaries, high- e binaries, ternary systems, and contact binaries. Our model only presupposes the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect, "rubble pile" asteroid geophysics, and gravitational interactions. The YORP effect torques a "rubble pile" asteroid until the asteroid reaches its fission spin limit and the components enter orbit about each other (Scheeres, D.J. [2007]. Icarus 189, 370-385). Non-spherical gravitational potentials couple the spin states to the orbit state and chaotically drive the system towards the observed asteroid classes along two evolutionary tracks primarily distinguished by mass ratio. Related to this is a new binary process termed secondary fission - the secondary asteroid of the binary system is rotationally accelerated via gravitational torques until it fissions, thu...

  7. Human Mission to Asteroids in the Context of Future Space Exploration Studies .

    Science.gov (United States)

    Messidoro, P.; Fenoglio, F.; Pasquinelli, M.; Gottlieb, J.

    The final goal, for the foreseeable future, of the Human Exploration of the Solar System is to land a crew on the Mars Surface (and to bring it back). A wide array of capabilities has to be developed and demonstrated before attempting such a risky endeavor; intermediate steps are therefore needed, also to comply with budget constraints. Human missions to Near Earth Objects (NEOs) and specifically Asteroids (NEAs) are among the most suitable candidates, thanks to high scientific interest, good opportunities for testing technologies and crew operations, and to mature Earth protection capabilities. In the following, a review of existing NEA Human mission concepts is provided and a new one, characterized by the exploitation of Nuclear Thermal Propulsion to reduce overall lift-off mass, is proposed.

  8. Difficult cases in photometric studies of asteroids

    Science.gov (United States)

    Marciniak, Anna; Pilcher, Frederick; Oszkiewicz, Dagmara; Bartczak, Przemysław; Santana-Ros, Toni; Kamiński, Krzysztof; Urakawa, Seitaro; Ogłoza, Waldemar; Fauvaud, Stéphane; Kankiewicz, Paweł; Kudak, Viktor; Żejmo, Michał; Nishiyama, Kota; Okumura, Shin-ichiro; Nimura, Tokuhiro; Hirsch, Roman; Konstanciak, Izabella; Tychoniec, Łukasz; Figas, Michał

    2016-06-01

    We present a photometric campaign targeted at asteroids that display both long periods of rotation and small amplitudes of brightness variations. Our aim is to debias available sample of spin and shape modelled asteroids and to correct previous wrong period determinations. Our newest findings are corrected period determinations for asteroids (279) Thule (P=23.896h ± 0.005 h), (673) Edda (P=22.340h ± 0.004 h), and (737) Arequipa (P=7.0259h ± 0.0003 h). Supporting lightcurves are presented in this paper.

  9. Spectroscopy of near-Earth asteroids

    DEFF Research Database (Denmark)

    Michelsen, René; Nathues, Andreas; Lagerkvist, Claes-Ingvar

    2006-01-01

    We present spectra and taxonomic classifications of 12 Near-Earth Asteroids (NEAs) and 2 inner Main Belt asteroids. The observations were carried out with the ESO 3.5 m NTT and the Danish 1.54 m telescope at La Silla, Chile. Eleven of the investigated NEAs belong to the S class while only one C......-type has been identified. Two NEAs were observed at phase angles larger than 60 degrees introducing significant phase reddening. In order to allow for comparisons between spectra of asteroids observed at different phase angles we make attempts to correct for this effect. However, it turned out...

  10. Spectroscopy of near-Earth asteroids

    DEFF Research Database (Denmark)

    Michelsen, René; Nathues, Andreas; Lagerkvist, Claes-Ingvar

    2006-01-01

    We present spectra and taxonomic classifications of 12 Near-Earth Asteroids (NEAs) and 2 inner Main Belt asteroids. The observations were carried out with the ESO 3.5 m NTT and the Danish 1.54 m telescope at La Silla, Chile. Eleven of the investigated NEAs belong to the S class while only one C......-type has been identified. Two NEAs were observed at phase angles larger than 60 degrees introducing significant phase reddening. In order to allow for comparisons between spectra of asteroids observed at different phase angles we make attempts to correct for this effect. However, it turned out...

  11. Asteroids@home - A BOINC distributed computing project for asteroid shape reconstruction

    CERN Document Server

    Durech, Josef; Vanco, Radim

    2015-01-01

    We present the project Asteroids@home that uses distributed computing to solve the time-consuming inverse problem of shape reconstruction of asteroids. The project uses the Berkeley Open Infrastructure for Network Computing (BOINC) framework to distribute, collect, and validate small computational units that are solved independently at individual computers of volunteers connected to the project. Shapes, rotational periods, and orientations of the spin axes of asteroids are reconstructed from their disk-integrated photometry by the lightcurve inversion method.

  12. Dynamics of rotationally fissioned asteroids: Source of observed small asteroid systems

    Science.gov (United States)

    Jacobson, Seth A.; Scheeres, Daniel J.

    2011-07-01

    We present a model of near-Earth asteroid (NEA) rotational fission and ensuing dynamics that describes the creation of synchronous binaries and all other observed NEA systems including: doubly synchronous binaries, high- e binaries, ternary systems, and contact binaries. Our model only presupposes the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect, "rubble pile" asteroid geophysics, and gravitational interactions. The YORP effect torques a "rubble pile" asteroid until the asteroid reaches its fission spin limit and the components enter orbit about each other (Scheeres, D.J. [2007]. Icarus 189, 370-385). Non-spherical gravitational potentials couple the spin states to the orbit state and chaotically drive the system towards the observed asteroid classes along two evolutionary tracks primarily distinguished by mass ratio. Related to this is a new binary process termed secondary fission - the secondary asteroid of the binary system is rotationally accelerated via gravitational torques until it fissions, thus creating a chaotic ternary system. The initially chaotic binary can be stabilized to create a synchronous binary by components of the fissioned secondary asteroid impacting the primary asteroid, solar gravitational perturbations, and mutual body tides. These results emphasize the importance of the initial component size distribution and configuration within the parent asteroid. NEAs may go through multiple binary cycles and many YORP-induced rotational fissions during their approximately 10 Myr lifetime in the inner Solar System. Rotational fission and the ensuing dynamics are responsible for all NEA systems including the most commonly observed synchronous binaries.

  13. ASIME 2016 White Paper: In-Space Utilisation of Asteroids: "Answers to Questions from the Asteroid Miners"

    OpenAIRE

    Graps, Amara L.; Blondel, Philippe; Bonin, Grant; Britt, Daniel; Centuori, Simone; Delbo, Marco; Drube, Line; Duffard, Rene; Elvis, Martin; Faber, Daniel; Frank, Elizabeth; Galache, JL; Green, Simon F.; Grundmann, Jan Thimo; Hsieh, Henry

    2016-01-01

    The aim of the Asteroid Science Intersections with In-Space Mine Engineering (ASIME) 2016 conference on September 21-22, 2016 in Luxembourg City was to provide an environment for the detailed discussion of the specific properties of asteroids, with the engineering needs of space missions that utilize asteroids. The ASIME 2016 Conference produced a layered record of discussions from the asteroid scientists and the asteroid miners to understand each other's key concerns and to address key scien...

  14. Business Center

    Science.gov (United States)

    Learn how to do business with EPA's Clean Air Markets, including registering to use the Emissions Collection and Monitoring Plan System (ECMPS), the CAMD Business System (CBS), and learn how to submit monitored emissions data.

  15. Business intelligence

    National Research Council Canada - National Science Library

    Cebotarean Elena

    2011-01-01

    Business intelligence (BI) refers to computer-based techniques used in spotting, digging-out, and analyzing business data, such as sales revenue by products and/or departments, or by associated costs and incomes...

  16. Water in Asteroid 4 Vesta

    Science.gov (United States)

    Taylor, G. J.

    2015-01-01

    Eucrite meteorites come from asteroid 4 Vesta, which was recently studied from orbit by NASA's Dawn mission. Adam Sarafian (Woods Hole Oceanographic Institute) and colleagues at Woods Hole, the University of Bristol, England, and the University of New Mexico measured the hydrogen concentration and deuterium/hydrogen (D/H) ratio in crystals of the mineral apatite (calcium phosphate) in eucrites. They found that the D/H ratio is in the same range as in carbonaceous chondrites, most samples of the Earth's mantle, and in samples of basaltic meteorites from Mars. Combined with measurements of the isotopic compositions of nitrogen and carbon, the data suggest that these volatile elements were added to Earth early in its history, probably during its formation. Other studies conclude that water with D/H like that in carbonaceous chondrites, Earth, Mars, and Vesta were likely inherited from interstellar ice that predates formation of the solar system.

  17. Business Plan

    OpenAIRE

    Radošinská, Jana

    2014-01-01

    Diploma thesis deals with the processing of a business plan to establish a tour operator, which will offer tours to Puerto Rico. Thesis is divided into theoretical and practical part. The theoretical part explains what is business and related terms. Defines the tourism business and the procedure for the establishment of tour operators. There are also theoretically explained individual chapters of a business plan. The practical part is dedicated to the establishment of tour operator, where is ...

  18. Progressive Business

    DEFF Research Database (Denmark)

    Christiansen, Christian O.

    2016-01-01

    Guest Post to the Society for U.S. Intellectual History Blog. Brief introduction to the book Progressive Business: An Intellectual History of the Role of Business in American Society, Oxford U.P., 2015.......Guest Post to the Society for U.S. Intellectual History Blog. Brief introduction to the book Progressive Business: An Intellectual History of the Role of Business in American Society, Oxford U.P., 2015....

  19. Playful Business

    DEFF Research Database (Denmark)

    Lund, Morten; Hansen, Poul H. Kyvsgård; Nielsen, Louise Møller

    2011-01-01

    ” The term business model can be defined as a business concept that has been put into practice. The increase in dynamics in markets, technology, economies etc. challenge the requirements to make consistent and synchronized decisions on which business models to develop and implement. Complexity...

  20. Business Law

    DEFF Research Database (Denmark)

    Föh, Kennet Fischer; Mandøe, Lene; Tinten, Bjarke

    Business Law is a translation of the 2nd edition of Erhvervsjura - videregående uddannelser. It is an educational textbook for the subject of business law. The textbook covers all important topic?s within business law such as the Legal System, Private International Law, Insolvency Law, Contract law...

  1. E-Business: The Business Officer's Business.

    Science.gov (United States)

    Olson, Mark A.

    2001-01-01

    Contends e-business is particularly the domain of college and university business officers, with today's officers facing an unprecedented opportunity to exercise a critical leadership role in the deployment of advanced information technology solutions on campus. Describes relevant issues and advances, and presents ten initiatives that business…

  2. Mineralogy and Surface Composition of Asteroids

    CERN Document Server

    Reddy, Vishnu; Thomas, Cristina A; Moskovitz, Nicholas A; Burbine, Thomas H

    2015-01-01

    Methods to constrain the surface mineralogy of asteroids have seen considerable development during the last decade with advancement in laboratory spectral calibrations and validation of our interpretive methodologies by spacecraft rendezvous missions. This has enabled the accurate identification of several meteorite parent bodies in the main asteroid belt and helped constrain the mineral chemistries and abundances in ordinary chondrites and basaltic achondrites. With better quantification of spectral effects due to temperature, phase angle, and grain size, systematic discrepancies due to non-compositional factors can now be virtually eliminated for mafic silicate-bearing asteroids. Interpretation of spectrally featureless asteroids remains a challenge. This paper presents a review of all mineralogical interpretive tools currently in use and outlines procedures for their application.

  3. Chelyabinsk: Portrait of an asteroid airburst

    Energy Technology Data Exchange (ETDEWEB)

    Kring, David A.; Boslough, Mark

    2014-09-01

    Video and audio from hundreds of smartphones and dashboard cameras combined with seismic, acoustic, and satellite measurements provide the first precise documentation of a 10 000-ton asteroid explosion.

  4. Colors of Dynamically Associated Asteroid Pairs

    CERN Document Server

    Moskovitz, Nicholas

    2012-01-01

    Recent dynamical studies have identified pairs of asteroids that reside in nearly identical heliocentric orbits. Possible formation scenarios for these systems include dissociation of binary asteroids, collisional disruption of a single parent body, or spin-up and rotational fission of a rubble-pile. Aside from detailed dynamical analyses and measurement of rotational light curves, little work has been done to investigate the colors or spectra of these unusual objects. A photometric and spectroscopic survey was conducted to determine the reflectance properties of asteroid pairs. New observations were obtained for a total of 34 individual asteroids. Additional photometric measurements were retrieved from the Sloan Digital Sky Survey Moving Object Catalog. Colors or spectra for a total of 42 pair components are presented here. The main findings of this work are: (1) the components in the observed pair systems have the same colors within the uncertainties of this survey, and (2) the color distribution of asteroi...

  5. Origins for the near-earth asteroids

    Science.gov (United States)

    Binzel, Richard P.; Xu, Shui; Bus, Schelte J.; Bowell, Edward

    1992-01-01

    Because of their short dynamical lifetimes, the population of near-earth asteroids (NEAs) must be resupplied. Two sources have been hypothesized: main-belt asteroids and extinct comet nuclei. A new survey of physical properties for less than 5 kilometers diameter main-belt asteroids reveals that their spin rate and shape distributions are similar to those of NEAs, as is fully consistent with a main-belt origin for most NEAs. Physical data on comet nuclei are limited. If the existing sample is representative of the comet population, analysis of the asteroid and comet samples constrains the fraction of comet nuclei to between 0 and 40 percent of the total NEA population.

  6. The Cratering History of Asteroid (21) Lutetia

    CERN Document Server

    Marchi, S; Vincent, J -B; Morbidelli, A; Mottola, S; Marzari, F; Kueppers, M; Besse, S; Thomas, N; Barbieri, C; Naletto, G; Sierks, H

    2011-01-01

    The European Space Agency's Rosetta spacecraft passed by the main belt asteroid (21) Lutetia the 10th July 2010. With its ~100km size, Lutetia is one of the largest asteroids ever imaged by a spacecraft. During the flyby, the on-board OSIRIS imaging system acquired spectacular images of Lutetia's northern hemisphere revealing a complex surface scarred by numerous impact craters, reaching the maximum dimension of about 55km. In this paper, we assess the cratering history of the asteroid. For this purpose, we apply current models describing the formation and evolution of main belt asteroids, that provide the rate and velocity distributions of impactors. These models, coupled with appropriate crater scaling laws, allow us to interpret the observed crater size-frequency distribution (SFD) and constrain the cratering history. Thanks to this approach, we derive the crater retention age of several regions on Lutetia, namely the time lapsed since their formation or global surface reset. We also investigate the influe...

  7. Asteroid models from the Lowell photometric database

    Science.gov (United States)

    Ďurech, J.; Hanuš, J.; Oszkiewicz, D.; Vančo, R.

    2016-03-01

    Context. Information about shapes and spin states of individual asteroids is important for the study of the whole asteroid population. For asteroids from the main belt, most of the shape models available now have been reconstructed from disk-integrated photometry by the lightcurve inversion method. Aims: We want to significantly enlarge the current sample (~350) of available asteroid models. Methods: We use the lightcurve inversion method to derive new shape models and spin states of asteroids from the sparse-in-time photometry compiled in the Lowell Photometric Database. To speed up the time-consuming process of scanning the period parameter space through the use of convex shape models, we use the distributed computing project Asteroids@home, running on the Berkeley Open Infrastructure for Network Computing (BOINC) platform. This way, the period-search interval is divided into hundreds of smaller intervals. These intervals are scanned separately by different volunteers and then joined together. We also use an alternative, faster, approach when searching the best-fit period by using a model of triaxial ellipsoid. By this, we can independently confirm periods found with convex models and also find rotation periods for some of those asteroids for which the convex-model approach gives too many solutions. Results: From the analysis of Lowell photometric data of the first 100 000 numbered asteroids, we derived 328 new models. This almost doubles the number of available models. We tested the reliability of our results by comparing models that were derived from purely Lowell data with those based on dense lightcurves, and we found that the rate of false-positive solutions is very low. We also present updated plots of the distribution of spin obliquities and pole ecliptic longitudes that confirm previous findings about a non-uniform distribution of spin axes. However, the models reconstructed from noisy sparse data are heavily biased towards more elongated bodies with high

  8. An Early Warning System for Asteroid Impact

    Science.gov (United States)

    Tonry, John L.

    2011-01-01

    Earth is bombarded by meteors, occasionally by one large enough to cause a significant explosion and possible loss of life. It is not possible to detect all hazardous asteroids, and the efforts to detect them years before they strike are only advancing slowly. Similarly, ideas for mitigation of the danger from an impact by moving the asteroid are in their infancy. Although the odds of a deadly asteroid strike in the next century are low, the most likely impact is by a relatively small asteroid, and we suggest that the best mitigation strategy in the near term is simply to move people out of the way. With enough warning, a small asteroid impact should not cause loss of life, and even portable property might be preserved. We describe an early warning system that could provide a week’s notice of most sizeable asteroids or comets on track to hit the Earth. This may be all the mitigation needed or desired for small asteroids, and it can be implemented immediately for relatively low cost. This system, dubbed Asteroid Terrestrial-Impact Last Alert System (ATLAS), comprises two observatories separated by about 100 km that simultaneously scan the visible sky twice a night. Software automatically registers a comparison with the unchanging sky and identifies everything that has moved or changed. Communications between the observatories lock down the orbits of anything approaching the Earth, within one night if its arrival is less than a week. The sensitivity of the system permits detection of 140 m asteroids (100 Mton impact energy) three weeks before impact and 50 m asteroids a week before arrival. An ATLAS alarm, augmented by other observations, should result in a determination of impact location and time that is accurate to a few kilometers and a few seconds. In addition to detecting and warning of approaching asteroids, ATLAS will continuously monitor the changing universe around us: most of the variable stars in our Galaxy, many microlensing events from stellar

  9. Modelling asteroid brightness variations. I - Numerical methods

    Science.gov (United States)

    Karttunen, H.

    1989-01-01

    A method for generating lightcurves of asteroid models is presented. The effects of the shape of the asteroid and the scattering law of a surface element are distinctly separable, being described by chosen functions that can easily be changed. The shape is specified by means of two functions that yield the length of the radius vector and the normal vector of the surface at a given point. The general shape must be convex, but spherical concavities producing macroscopic shadowing can also be modeled.

  10. Olivine-dominated asteroids: Mineralogy and origin

    OpenAIRE

    Sanchez, Juan A.; Reddy, Vishnu; Kelley, Michael S.; Cloutis, Edward A.; Bottke, William F.; Nesvorný, David; Lucas, Michael P.; Hardersen, Paul S.; Gaffey, Michael J.; Abell, Paul A.; Corre, Lucille Le

    2013-01-01

    Olivine-dominated asteroids are a rare type of objects formed either in nebular processes or through magmatic differentiation. The analysis of meteorite samples suggest that at least 100 parent bodies in the main belt experienced partial or complete melting and differentiation before being disrupted. However, only a few olivine-dominated asteroids, representative of the mantle of disrupted differentiated bodies, are known to exist. Due to the paucity of these objects in the main belt their or...

  11. Playful Business

    DEFF Research Database (Denmark)

    Lund, Morten; Hansen, Poul H. Kyvsgård; Nielsen, Louise Møller

    2011-01-01

    ” The term business model can be defined as a business concept that has been put into practice. The increase in dynamics in markets, technology, economies etc. challenge the requirements to make consistent and synchronized decisions on which business models to develop and implement. Complexity...... seems to be the crucial phenomenon that challenges most organizations. In order to deal with these challenges it seems to be relevant to include elements of games, simulations, and more open workshops. However, in order to deliver relevant clarifications such combined methods have to be facilitated...... efficiently. This paper describes initial experiences of facilitating business model mapping or business model innovation by game-like setups.”...

  12. Formation of asteroid pairs by rotational fission.

    Science.gov (United States)

    Pravec, P; Vokrouhlický, D; Polishook, D; Scheeres, D J; Harris, A W; Galád, A; Vaduvescu, O; Pozo, F; Barr, A; Longa, P; Vachier, F; Colas, F; Pray, D P; Pollock, J; Reichart, D; Ivarsen, K; Haislip, J; Lacluyze, A; Kusnirák, P; Henych, T; Marchis, F; Macomber, B; Jacobson, S A; Krugly, Yu N; Sergeev, A V; Leroy, A

    2010-08-26

    Pairs of asteroids sharing similar heliocentric orbits, but not bound together, were found recently. Backward integrations of their orbits indicated that they separated gently with low relative velocities, but did not provide additional insight into their formation mechanism. A previously hypothesized rotational fission process may explain their formation-critical predictions are that the mass ratios are less than about 0.2 and, as the mass ratio approaches this upper limit, the spin period of the larger body becomes long. Here we report photometric observations of a sample of asteroid pairs, revealing that the primaries of pairs with mass ratios much less than 0.2 rotate rapidly, near their critical fission frequency. As the mass ratio approaches 0.2, the primary period grows long. This occurs as the total energy of the system approaches zero, requiring the asteroid pair to extract an increasing fraction of energy from the primary's spin in order to escape. We do not find asteroid pairs with mass ratios larger than 0.2. Rotationally fissioned systems beyond this limit have insufficient energy to disrupt. We conclude that asteroid pairs are formed by the rotational fission of a parent asteroid into a proto-binary system, which subsequently disrupts under its own internal system dynamics soon after formation.

  13. Asteroid hyalosis--current state of knowledge.

    Science.gov (United States)

    Jabłońska, Anna; Ciszewska, Joanna; Kęcik, Dariusz

    2014-01-01

    The search query into the Cochrane Library, Medline, Web of Science, Embase, Scopus and ScienceDirect enabled selection of research papers addressing the issue of asteroid hyalosis published in English between 1963 and January 2014. Asteroid hyalosis is a degenerative condition of the vitreous in which small, creamy or white, spherical particles (asteroid bodies) are randomly diffused within the vitreous. They consist mainly of calcium and phosphorus and have a structure of hydroxy lapatite. In 80.2-92.0% of cases the condition affects one eye only and it occurs in 0.36-1.96% of population, mostly in patients over 50 years of age and in males. Hypercholesterolemia and hypertension are systemic risk factors, but asteroid hyalosis is postulated to occur more often in retinitis pigmentosa and Leber amaurosis caused by mutations in lecithin retinol acyltransferase gene. Asteroid hyalosis also causes calcification of some intraocular lenses--mostly silicone ones. Vitreous of patients with asteroid hyalosis shows reduced gel liquefaction and anomalous vitreoretinal adhesion.

  14. An Early Warning System for Asteroid Impact

    CERN Document Server

    Tonry, John L

    2010-01-01

    Earth is bombarded by meteors, occasionally by one large enough to cause a significant explosion and possible loss of life. Although the odds of a deadly asteroid strike in the next century are low, the most likely impact is by a relatively small asteroid, and we suggest that the best mitigation strategy in the near term is simply to move people out of the way. We describe an "early warning" system that could provide a week's notice of most sizable asteroids or comets on track to hit the Earth. This system, dubbed "Asteroid Terrestrial-impact Last Alert System" (ATLAS), comprises two observatories separated by about 100km that simultaneously scan the visible sky twice a night, and can be implemented immediately for relatively low cost. The sensitivity of ATLAS permits detection of 140m asteroids (100 Mton impact energy) three weeks before impact, and 50m asteroids a week before arrival. An ATLAS alarm, augmented by other observations, should result in a determination of impact location and time that is accura...

  15. Asteroid secular dynamics: Ceres' fingerprint identified

    CERN Document Server

    Novaković, Bojan; Tsirvoulis, Georgios; Knezević, Zoran

    2015-01-01

    Here we report on the significant role of a so far overlooked dynamical aspect, namely a secular resonance between the dwarf planet Ceres and other asteroids. We demonstrate that this type of secular resonance can be the dominant dynamical factor in certain regions of the main asteroid belt. Specifically, we performed a dynamical analysis of the asteroids belonging to the (1726) Hoffmeister family. To identify which dynamical mechanisms are actually at work in this part of the main asteroid belt, i.e. to isolate the main perturber(s), we study the evolution of this family in time. The study is accomplished using numerical integrations of test particles performed within different dynamical models. The obtained results reveal that the post-impact evolution of the Hoffmeister asteroid family is a direct consequence of the nodal secular resonance with Ceres. This leads us to the conclusion that similar effects must exist in other parts of the asteroid belt. In this respect, the obtained results shed light on an i...

  16. Asteroid Models from Multiple Data Sources

    CERN Document Server

    Durech, J; Delbo, M; Kaasalainen, M; Viikinkoski, M

    2015-01-01

    In the past decade, hundreds of asteroid shape models have been derived using the lightcurve inversion method. At the same time, a new framework of 3-D shape modeling based on the combined analysis of widely different data sources such as optical lightcurves, disk-resolved images, stellar occultation timings, mid-infrared thermal radiometry, optical interferometry, and radar delay-Doppler data, has been developed. This multi-data approach allows the determination of most of the physical and surface properties of asteroids in a single, coherent inversion, with spectacular results. We review the main results of asteroid lightcurve inversion and also recent advances in multi-data modeling. We show that models based on remote sensing data were confirmed by spacecraft encounters with asteroids, and we discuss how the multiplication of highly detailed 3-D models will help to refine our general knowledge of the asteroid population. The physical and surface properties of asteroids, i.e., their spin, 3-D shape, densit...

  17. The typological approach to the risky behavior of adolescents

    Directory of Open Access Journals (Sweden)

    Mitrović D.

    2006-01-01

    Full Text Available The main research problem is focused on the following question: Is it possible to identify specific patterns of interaction between precipitating and protective factors for the risky behavior among adolescents. The research was conducted on the sample of 204 adolescents of both genders (18 to 20 years old. Specific personality traits and socio-demographic characteristics are manifested as the most important precipitating and/or protective factors for the risky behavior. The frame of reference for personality assessment was the alternative five-factor model (Zuckerman, 2002, specified in the ZKPQ-50-CC questionnaire, and consisted of the five biologically determined personality traits: activity, aggressiveness/hostility, impulsive sensation seeking, neuroticism/anxiety and sociability. Latent dimensions of the risky behavior: risky activities and life - conditions, were extracted by applying the homogeneity analyses (HOMALS. The matrix of squared Euclidean distances (in the common space of factor scores on the principal components of ZKPQ questionnaire, scores on HOMALS dimensions and school grades was a subject of the Ward hierarchical cluster analysis method, extracting three clusters. According to the discriminant functions: risk proneness and pro-social activity, the clusters were identified: the group of pro-social oriented adolescents, the aloof group and the group of adolescents prone to risky behavior. The results have considerable implications for the prevention programs’ development and implementation.

  18. Acute stress does not affect risky monetary decision-making

    Directory of Open Access Journals (Sweden)

    Peter Sokol-Hessner

    2016-12-01

    Full Text Available The ubiquitous and intense nature of stress responses necessitate that we understand how they affect decision-making. Despite a number of studies examining risky decision-making under stress, it is as yet unclear whether and in what way stress alters the underlying processes that shape our choices. This is in part because previous studies have not separated and quantified dissociable valuation and decision-making processes that can affect choices of risky options, including risk attitudes, loss aversion, and choice consistency, among others. Here, in a large, fully-crossed two-day within-subjects design, we examined how acute stress alters risky decision-making. On each day, 120 participants completed either the cold pressor test or a control manipulation with equal probability, followed by a risky decision-making task. Stress responses were assessed with salivary cortisol. We fit an econometric model to choices that dissociated risk attitudes, loss aversion, and choice consistency using hierarchical Bayesian techniques to both pool data and allow heterogeneity in decision-making. Acute stress was found to have no effect on risk attitudes, loss aversion, or choice consistency, though participants did become more loss averse and more consistent on the second day relative to the first. In the context of an inconsistent previous literature on risk and acute stress, our findings provide strong and specific evidence that acute stress does not affect risk attitudes, loss aversion, or consistency in risky monetary decision-making.

  19. Acute stress does not affect risky monetary decision-making.

    Science.gov (United States)

    Sokol-Hessner, Peter; Raio, Candace M; Gottesman, Sarah P; Lackovic, Sandra F; Phelps, Elizabeth A

    2016-12-01

    The ubiquitous and intense nature of stress responses necessitate that we understand how they affect decision-making. Despite a number of studies examining risky decision-making under stress, it is as yet unclear whether and in what way stress alters the underlying processes that shape our choices. This is in part because previous studies have not separated and quantified dissociable valuation and decision-making processes that can affect choices of risky options, including risk attitudes, loss aversion, and choice consistency, among others. Here, in a large, fully-crossed two-day within-subjects design, we examined how acute stress alters risky decision-making. On each day, 120 participants completed either the cold pressor test or a control manipulation with equal probability, followed by a risky decision-making task. Stress responses were assessed with salivary cortisol. We fit an econometric model to choices that dissociated risk attitudes, loss aversion, and choice consistency using hierarchical Bayesian techniques to both pool data and allow heterogeneity in decision-making. Acute stress was found to have no effect on risk attitudes, loss aversion, or choice consistency, though participants did become more loss averse and more consistent on the second day relative to the first. In the context of an inconsistent previous literature on risk and acute stress, our findings provide strong and specific evidence that acute stress does not affect risk attitudes, loss aversion, or consistency in risky monetary decision-making.

  20. Risky attitudes towards road use in pre-drivers.

    Science.gov (United States)

    Waylen, Andrea E; McKenna, Frank P

    2008-05-01

    Motor vehicle accidents are one of the principal causes of adolescent disability or mortality and male drivers are more likely to be involved in road accidents than female drivers. In part such associations between driver age and sex have been linked to differences in risky behaviour (e.g. speed, violations) and individual characteristics (e.g. sensation seeking, deviant behaviour). The aim of this research is to determine whether associations between risky road user behaviour and individual characteristics are a function of driver behaviour or whether they are intrinsic and measurable in individuals too young to drive. Five hundred and sixty-seven pre-driver students aged 11-16 from three secondary schools completed questionnaires measuring enthusiasm for speed, sensation seeking, deviant behaviour and attitudes towards driver violations. Boys reported more risky attitudes than girls for all measures. Associations between sensation seeking, deviant behaviour and attitudes towards risky road use were present from early adolescence and were strongest around age 14, before individuals learn to drive. Risky attitudes towards road use are associated with individual characteristics and are observed in adolescents long before they learn to drive. Safe attitudes towards road use and driver behaviour should be promoted from childhood in order to be effective.

  1. Features and behavioral principles in the business context

    Directory of Open Access Journals (Sweden)

    Teaching Assistant

    2010-12-01

    Full Text Available In the contemporary market economy constant improvement of business environment is an important element in achieving business. Digital economy affects business growth, innovation and technological progress became also important instruments in the activity of any organization.Organizations are trying to find and develop intelligent tools and strategies for the new business models. Managers’ major concern is to find intelligent solutions for the business management. In our days being an entrepreneur it is a difficult choice. The entrepreneur must deal with difficult and risky situations which can affect his/her activities. The purpose of this paper is to present those elements which can less or more affect the existing business environment. Today is important how an entrepreneur acts on the potential market. Performance obtained by him/her depends on his ability to apply strategies and to use advanced information systems

  2. Business support within business incubators

    NARCIS (Netherlands)

    Ratinho, Tiago; Harms, Rainer; Groen, Arend J.

    2009-01-01

    Business incubators (BI) have been established worldwide as tools for company creation and small businesses support. BIs claim to help their tenants by providing them with the optimal conditions for increasing early stage survival. Practitioners and researchers agree that business support is a

  3. Lightcurves for Two Near-Earth Asteroids by Asteroids Observers (OBAS) - MPPD: 2016 April-May

    Science.gov (United States)

    Martinez, Vicente Mas; Silva, Gonzalo Fornas; Martinez, Angel Flores; Garceran, Alfonso Carreno; Mansego, Enrique Arce; Rodriguez, Pedro Brines; de Haro, Juan Lozano; Silva, Alvaro Fornas; Chiner, Onofre Rodrigo; Porta, David Herrero

    2016-10-01

    We report on the results of photometric analysis of two near-Earth asteroids (NEA) by Asteroids Observers (OBAS). This work is part of the Minor Planet Photometric Database (MPPD) project initiated by a group of Spanish amateur astronomers. We have managed to obtain a number of accurate and complete lightcurves as well as some additional incomplete lightcurves to help analysis at future oppositions.

  4. Sixteen Asteroids Lightcurves at Asteroids Observers (OBAS) - MPPD: 2016 June-November

    Science.gov (United States)

    Brines, Pedro; Lozano, Juan; Rodrigo, Onofre; Fornas, A.; Herrero, David; Mas, Vicente; Fornas, G.; Carreño, A.; Arce, Enrique

    2017-04-01

    We report on the photometric analysis result of sixteen main-belt asteroids (MBA) done by Asteroids Observers (OBAS). This work is part of the Minor Planet Photometric Database tasks, initiated by a group of Spanish amateur astronomers. We have managed to obtain a number of accurate and complete lightcurves as well as some additional incomplete lightcurves to help analysis at future oppositions.

  5. Eighteen Asteroids Lightcurves at Asteroides Observers (OBAS) - MPPD: 2016 March-May

    Science.gov (United States)

    Mansego, Enrique Arce; Rodriguez, Pedro Brines; de Haro, Juan Lozano; Chiner, Onofre Rodrigo; Silva, Alvaro Fornas; Porta, David Herrero; Martinez, Vicente Mas; Silva, Gonzalo Fornas; Garceran, Alfonso Carreno

    2016-10-01

    We report on the analysis of photometric observations of 18 main-belt asteroids (MBA) done by Asteroides Observers (OBAS). This work is part of the Minor Planet Photometric Database program initiated by a group of Spanish amateur astronomers. We have managed to obtain a number of accurate and complete lightcurves as well as some additional incomplete lightcurves to help analysis at future oppositions.

  6. Twenty-three Asteroids Lightcurves at Observadores de Asteroides (OBAS): 2015 October - December

    Science.gov (United States)

    Aznar Macias, Amadeo; Carreno Garcerain, Alfonso; Arce Mansego, Enrique; Brines Rodriguez, Pedro; Lozano de Haro, Juan; Fornas Silva, Alvaro; Fornas Silva, Gonzalo; Mas Martinez, Vicente; Rodrigo Chiner, Onofre

    2016-04-01

    We report on the photometric analysis results for 23 main-belt asteroids (MBA) done by Observadores de Asteroides (OBAS). This work is part of the Minor Planet Photometric Database that was initiated by a group of Spanish amateur astronomers. We have managed to obtain a number of accurate, complete lightcurves as well as some additional incomplete lightcurves to help analysis at future oppositions.

  7. International CJMT-1 Workshop on Asteroidal Science

    Science.gov (United States)

    Ip, Wing-Huen

    2014-03-01

    An international workshop on asteroidal science was held between October 16 and 17, 2012, at the Macau University of Science and Technology gathering together experts on asteroidal study in China, Japan, Macao and Taiwan. For this reason, we have called it CJMT-1 Workshop. Though small in sizes, the asteroids orbiting mainly between the orbit of Mars and of Jupiter have important influence on the evolution of the planetary bodies. Topics ranging from killer asteroids to space resources are frequently mentioned in news reports with prominence similar to the search for water on Mars. This also means that the study of asteroids is very useful in exciting the imagination and interest in science of the general public. Several Asian countries have therefore developed long-term programs integrating ground-based observations and space exploration with Japan being the most advanced and ambitious as demonstrated by the very successful Hayabusa mission to asteroid 25143 Itokawa. In this volume we will find descriptions of the mission planning of Hayabusa II to the C-type near-Earth asteroid, 1999 JU3. Not to be outdone, China's Chang-E 2 spacecraft was re-routed to a flyby encounter with asteroid 4179 Toutatis in December 2012. It is planned that in the next CJMT workshop, we will have the opportunity to learn more about the in-depth data analysis of the Toutatis observations and the progress reports on the Hayabusa II mission which launch date is set to be July 2014. Last but not least, the presentations on the ground-based facilities as described in this volume will pave the way for coordinated observations of asteroidal families and Trojan asteroids - across Asia from Taiwan to Uzbekistan. Such international projects will serve as an important symbol of good will and peaceful cooperation among the key members of this group. Finally, I want to thank the Space Science Institute, Macao University of Science and Technology, for generous support, and its staff members

  8. Lightcurve Survey of V-type Asteroids in the Inner Asteroid Belt

    CERN Document Server

    Hasegawa, Sunao; Mito, Hiroyuki; Sarugaku, Yuki; Ozawa, Tomohiko; Kuroda, Daisuke; Nishihara, Setsuko; Harada, Akari; Yoshida, Michitoshi; Yanagisawa, Kenshi; Shimizu, Yasuhiro; Nagayama, Shogo; Toda, Hiroyuki; Okita, Kouji; Kawai, Nobuyuki; Mori, Machiko; Sekiguchi, Tomohiko; Ishiguro, Masateru; Abe, Takumi; Abe, Masanao

    2013-01-01

    We have observed the lightcurves of 13 V-type asteroids ((1933) Tinchen, (2011) Veteraniya, (2508) Alupka, (3657) Ermolova, (3900) Knezevic, (4005) Dyagilev, (4383) Suruga, (4434) Nikulin, (4796) Lewis, (6331) 1992 $\\mathrm{FZ_{1}}$, (8645) 1998 TN, (10285) Renemichelsen, and (10320) Reiland). Using these observations we determined the rotational rates of the asteroids, with the exception of Nikulin and Renemichelsen. The distribution of rotational rates of 59 V-type asteroids in the inner main belt, including 29 members of the Vesta family that are regarded as ejecta from the asteroid (4) Vesta, is inconsistent with the best-fit Maxwellian distribution. This inconsistency may be due to the effect of thermal radiation Yarkovsky--O'Keefe--Radzievskii--Paddack (YORP) torques, and implies that the collision event that formed V-type asteroids is sub-billion to several billion years in age.

  9. Mitigation of Hazardous Comets and Asteroids

    Science.gov (United States)

    Belton, Michael J. S.; Morgan, Thomas H.; Samarasinha, Nalin H.; Yeomans, Donald K.

    2011-03-01

    Preface; 1. Recent progress in interpreting the nature of the near-Earth object population W. Bottke, A. Morbidelli and R. Jedicke; 2. Earth impactors: orbital characteristics and warning times S. R. Chesley and T. B. Spahr; 3. The role of radar in predicting and preventing asteroid and comet collisions with Earth S. J. Ostro and J. D. Giorgini; 4. Interior structures for asteroids and cometary nuclei E. Asphaug; 5. What we know and don't know about surfaces of potentially hazardous small bodies C. R. Chapman; 6. About deflecting asteroids and comets K. A. Holsapple; 7. Scientific requirements for understanding the near-Earth asteroid population A. W. Harris; 8. Physical properties of comets and asteroids inferred from fireball observations M. D. Martino and A. Cellino; 9. Mitigation technologies and their requirements C. Gritzner and R. Kahle; 10. Peering inside near-Earth objects with radio tomography W. Kofman and A. Safaeinili; 11. Seismological imvestigation of asteroid and comet interiors J. D. Walker and W. F. Huebner; 12. Lander and penetrator science for near-Earth object mitigation studies A. J. Ball, P. Lognonne, K. Seiferlin, M. Patzold and T. Spohn; 13. Optimal interpretation and deflection of Earth-approaching asteroids using low-thrust electric propulsion B. A. Conway; 14. Close proximity operations at small bodies: orbiting, hovering, and hopping D. J. Scheeres; 15. Mission operations in low gravity regolith and dust D. Sears, M. Franzen, S. Moore, S. Nichols, M. Kareev and P. Benoit; 16. Impacts and the public: communicating the nature of the impact hazard D. Morrison, C. R. Chapman, D. Steel and R. P. Binzel; 17. Towards a program to remove the threat of hazardous NEOs M. J. S. Belton.

  10. Using Dust from Asteroids as Regolith Microsamples

    Science.gov (United States)

    Cohen, B. A.; Klima, Rachel; Chabot, N. L.; Rivkin, A. S.

    2015-01-01

    Meteorite science is rich with compositional indicators by which we classify parent bodies, but few sample groups are definitively linked with asteroid spectra. More robust links need to be forged between meteorites and their parent bodies to understand the composition, diversity and distribution. A major link can be sample analysis of the parent body material and comparison with meteorite data. Hayabusa, the first sample return mission of the Japanese Aerospace Exploration Agency (JAXA), was developed to rendezvous with and collect samples from asteroid Itokawa and return them to Earth. Thousands of sub-100 micron particles were recovered, apparently introduced during the spacecraft impact into the surface of the asteroid, linking the asteroid Itokawa to LL chondrites [1]. Upcoming missions Hayabusa 2 and OSIRIS-REx will collect more significant sample masses from asteroids. In all these cases, the samples are or will be a collection of regolith particles. Sample return to earth is not the only method for regolith particle analysis. Dust is present around all airless bodies, generated by micrometeorite impact into their airless surfaces, which in turn lofts regolith particles into a "cloud" around the body. The composition, flux, and size-frequency distribution of dust particles can provide significant insight into the geological evolution of airless bodies [2]. For example, the Cassini Cosmic Dust Analyzer (CDA) detected salts in Enceladus' icy plume material, providing evidence for a subsurface ocean in contact with a silicate seafloor [3]. Similar instruments have flown on the Rosetta, LADEE, and Stardust missions. Such an instrument may be of great use in obtaining the elemental, isotopic and mineralogical composition measurement of dust particles originating from asteroids without returning the samples to terrestrial laboratories. We investigated the ability of a limited sample analysis capability using a dust instrument to forge links between asteroid

  11. Aqueous alteration on main-belt asteroids

    Science.gov (United States)

    Fornasier, S.; Lantz, C.; Barucci, M.; Lazzarin, M.

    2014-07-01

    The study of aqueous alteration is particularly important for unraveling the processes occurring during the earliest times in Solar System history, as it can give information both on the thermal processes and on the localization of water sources in the asteroid belt, and for the associated astrobiological implications. The aqueous alteration process produces the low temperature (< 320 K) chemical alteration of materials by liquid water which acts as a solvent and produces materials like phyllosilicates, sulphates, oxides, carbonates, and hydroxides. This means that liquid water was present in the primordial asteroids, produced by the melting of water ice by heating sources, very probably by ^{26}Al decay. Hydrated minerals have been found mainly on Mars surface, on primitive main-belt asteroids (C, G, B, F, and P-type, following the classification scheme by Tholen, 1984) and possibly also on few transneptunian objects. Reflectance spectroscopy of aqueous altered asteroids shows absorption features in the 0.6-0.9 and 2.5-3.5-micron regions, which are diagnostic of, or associated with, hydrated minerals. In this work, we investigate the aqueous alteration process on a large sample of 600 visible spectra of C-complex asteroids available in the literature. We analyzed all these spectra in a similar way to characterize the absorption-band parameters (band center, depth, and width) and spectral slope, and to look for possible correlations between the aqueous alteration process and the asteroids taxonomic classes, orbital elements, heliocentric distances, albedo, and sizes. We find that 4.6 % of P, 7.7 % of F, 9.8 % of B, 50.5 % of C, and 100 % of the G-type asteroids have absorption bands in the visible region due to hydrated silicates. Our analysis shows that the aqueous alteration sequence starts from the P-type objects, practically unaltered, and increases through the P → F → B → C → G asteroids, these last being widely aqueously altered, strengthening thus

  12. Disrupting Business

    DEFF Research Database (Denmark)

    Cox, Geoff; Bazzichelli, Tatiana

    Disruptive Business explores some of the interconnections between art, activism and the business concept of disruptive innovation. With a backdrop of the crisis of financial capitalism, austerity cuts in the cultural sphere, the idea is to focus on potential art strategies in relation to a broken...... economy. In a perverse way, we ask whether this presents new opportunities for cultural producers to achieve more autonomy over their production process. If it is indeed possible, or desirable, what alternative business models emerge? The book is concerned broadly with business as material for reinvention...

  13. Disrupting Business

    DEFF Research Database (Denmark)

    Cox, Geoff; Bazzichelli, Tatiana

    Disruptive Business explores some of the interconnections between art, activism and the business concept of disruptive innovation. With a backdrop of the crisis of financial capitalism, austerity cuts in the cultural sphere, the idea is to focus on potential art strategies in relation to a broken...... economy. In a perverse way, we ask whether this presents new opportunities for cultural producers to achieve more autonomy over their production process. If it is indeed possible, or desirable, what alternative business models emerge? The book is concerned broadly with business as material for reinvention...

  14. A Fast Ellipsoid Model for Asteroids Inverted From Lightcurves

    CERN Document Server

    Lu, Xiaoping; You, Zhong

    2012-01-01

    The research about asteroids attracts more and more attention recently, especially focusing on their physical structures, such as the spin axis, the rotation period and the shape. The long distance between Earth observers and asteroids makes it impossible to get the shape and other parameters of asteroids directly with the exception of the NEAs (Near Earth Asteroids) and others passed by some spacecrafts. Generally photometric measurement is still the main way to obtain the research data for asteroids now, i.e. the lightcurves recording the brightness and positions of asteroids. Supposing that the shape of the asteroid is a triaxial ellipsoid with a stable spinning status, a new method is present in this article to reconstruct the shape models of asteroids from the lightcurves, with the other physical parameters together. By applying a special curvature function, the method calculates the brightness integration on a unit sphere and Lebedev Quadrature is employed for the discretization. At last the method sear...

  15. A Search for Asteroids, Moons, and Rings Orbiting White Dwarfs

    CERN Document Server

    Di Stefano, Rosanne; Kawaler, Steven D

    2009-01-01

    Do white dwarfs host asteroid systems? Although several lines of argument suggest that white dwarfs may be orbited by large populations of asteroids, transits would provide the most direct evidence. We demonstrate that the Kepler mission has the capability to detect transits of white dwarfs by asteroids. Because white-dwarf asteroid systems, if they exist, are likely to contain many asteroids orbiting in a spatially extended distribution, discoveries of asteroid transits can be made by monitoring only a small number of white dwarfs, compatible with Kepler's primary mission, which is to monitor stars with potentially habitable planets. Possible future missions that survey ten times as many stars with similar sensitivity and minute-cadence monitoring can establish the characteristics of asteroid systems around white dwarfs, such as the distribution of asteroid sizes and semimajor axes. Transits by planets would be more dramatic, but the probability that they will occur is lower. Ensembles of planetary moons and...

  16. Human Robotic Systems (HRS): Robotic Technologies for Asteroid Missions Element

    Data.gov (United States)

    National Aeronautics and Space Administration — During 2014, the Robotic Technologies for Asteroid Missions activity has four tasks:Asteroid Retrieval Capture Mechanism Development and Testbed;Mission Operations...

  17. Rotational properties of Maria asteroid family

    CERN Document Server

    Kim, Myung-Jin; Moon, Hong-Kyu; Byun, Yong-Ik; Brosch, Noah; Kaplan, Murat; Kaynar, Suleyman; Uysal, Omer; Guzel, Eda; Behrend, Raoul; Yoon, Joh-Na; Mottola, Stefano; Hellmich, Stephan; Hinse, Tobias C; Eker, Zeki; Park, Jang-Hyun

    2013-01-01

    Maria family is regarded as an old-type (~3 +/- 1 Gyr) asteroid family which has experienced substantial collisional and dynamical evolution in the Main-belt. It is located nearby the 3:1 Jupter mean motion resonance area that supplies Near-Earth asteroids (NEAs) to the inner Solar System. We carried out observations of Maria family asteroids during 134 nights from 2008 July to 2013 May, and derived synodic rotational periods for 51 objects, including newly obtained periods of 34 asteroids. We found that there is a significant excess of fast and slow rotators in observed rotation rate distribution. The two-sample Kolmogorov-Smirnov test confirms that the spin rate distribution is not consistent with a Maxwellian at a 92% confidence level. From correlations among rotational periods, amplitudes of lightcurves, and sizes, we conclude that the rotational properties of Maria family asteroids have been changed considerably by non-gravitational forces such as the YORP effect. Using a lightcurve inversion method (Kaa...

  18. The Dynamical Evolution of the Asteroid Belt

    CERN Document Server

    Morbidelli, Alessandro; O'Brien, David P; Minton, David A; Bottke, William F

    2015-01-01

    The asteroid belt is the leftover of the original planetesimal population in the inner solar system. However, currently the asteroids have orbits with all possible values of eccentricities and inclinations compatible with long-term dynamical stability, whereas the initial planetesimal orbits should have been quasi-circular and almost co-planar. The total mass in the asteroid population is a small fraction of that existing primordially. Also, asteroids with different chemical/mineralogical properties are not ranked in an orderly manner with mean heliocentric distance as one could expect from the existence of a radial gradient of the temperature in the proto-planetary disk, but they are partially mixed. These properties show that the asteroid belt has been severely sculpted by one or a series of processes during its lifetime. This paper reviews the processes that have been proposed so far, discussing the properties that they explain and the problems that they are confronted with. Emphasis is paid to the interpl...

  19. Search for a Differentiated Asteroid Family

    Science.gov (United States)

    Thomas, Cristina A.; Lim, Lucy F.; Trilling, David E.; Moskovitz, Nicholas

    2014-08-01

    Dynamical asteroid families resulting from catastrophic disruptions represent the interiors of their former parent bodies. Differentiation of a large initially chondritic parent body is expected to produce an ``onion shell" object with a metal core, a thick olivine-rich mantle, and a thin basaltic crust. However, instead of the mineralogical diversity expected from the disruption of a differentiated parent body, most asteroid families tend to show similar spectra among the members. Moreover, spectra of metal-like materials and olivine-dominated assemblages have not been detected in asteroid families in the Main Belt and the expected mantle material is missing from the meteorite record. The deficit of olivine-rich mantle material in the meteorite record and in asteroid observations is known as the ``Missing Mantle" problem. For years the best explanation for the lack of mantle material has been the ``battered to bits" hypothesis that states that all differentiated parent bodies (aside from Vesta) were disrupted very early in the solar system and the resulting olivine-rich material was collisionally broken down until the object diameters fell below our observational limits. However, in a new, competing, hypothesis, Elkins-Tanton et al. (2013) has suggested that previous work has overestimated the amount of olivine produced by the differentiation of a chondritic parent body. We propose to obtain visible spectra of asteroids within the Massalia, Merxia, and Agnia S-type families to search for compositional variations that are indicators of differentiation and to quantitatively constrain the two competing ``Missing Mantle" hypotheses.

  20. Thermal Tomography of Asteroid Surface Structure

    CERN Document Server

    Harris, Alan

    2016-01-01

    Knowledge of the surface thermal inertia of an asteroid can provide insight into surface structure: porous material has a lower thermal inertia than rock. We develop a means to estimate thermal inertia values of asteroids and use it to show that thermal inertia appears to increase with spin period in the case of main-belt asteroids (MBAs). Similar behavior is found on the basis of thermophysical modeling for near-Earth objects (NEOs). We interpret our results in terms of rapidly increasing material density and thermal conductivity with depth, and provide evidence that thermal inertia increases by factors of 10 (MBAs) to 20 (NEOs) within a depth of just 10 cm. Our results are consistent with a very general picture of rapidly changing material properties in the topmost regolith layers of asteroids and have important implications for calculations of the Yarkovsky effect, including its perturbation of the orbits of potentially hazardous objects and those of asteroid family members after the break-up event. Eviden...

  1. Thermal Tomography of Asteroid Surface Structure

    Science.gov (United States)

    Harris, Alan W.; Drube, Line

    2016-12-01

    Knowledge of the surface thermal inertia of an asteroid can provide insight into its surface structure: porous material has a lower thermal inertia than rock. We develop a means to estimate thermal inertia values of asteroids and use it to show that thermal inertia appears to increase with spin period in the case of main-belt asteroids (MBAs). Similar behavior is found on the basis of thermophysical modeling for near-Earth objects (NEOs). We interpret our results in terms of rapidly increasing material density and thermal conductivity with depth, and provide evidence that thermal inertia increases by factors of 10 (MBAs) to 20 (NEOs) within a depth of just 10 cm. Our results are consistent with a very general picture of rapidly changing material properties in the topmost regolith layers of asteroids and have important implications for calculations of the Yarkovsky effect, including its perturbation of the orbits of potentially hazardous objects and those of asteroid family members after the break-up event. Evidence of a rapid increase of thermal inertia with depth is also an important result for studies of the ejecta-enhanced momentum transfer of impacting vehicles (“kinetic impactors”) in planetary defense.

  2. Space Rocks: A Series of Papers on Meteorites and Asteroids

    OpenAIRE

    Hooper, Nina Louise

    2016-01-01

    The subject of this work is the compositions of asteroids and meteorites. Studies of the composition of small Solar System bodies are fundamental to theories of planet formation. Meteorites, samples available for analysis in the lab, help constrain the timeline and conditions in the early Solar System. Asteroid reflectance spectra help define the links between asteroids and meteorites. Studies of the spectral types and sizes of asteroids test dynamical models. These studie...

  3. Characterization of the near-Earth Asteroid 2002NY40

    OpenAIRE

    Roberts, Jr., Lewis C.; Hall, Doyle T.; Lambert, John V.; Africano, John L.; Knox, Keith T.; Barros, Jacob K.; Hamada, Kris M.; Liang, Dennis; Sydney, Paul F.; Kervin, Paul

    2007-01-01

    In August 2002, the near-Earth asteroid 2002 NY40, made its closest approach to the Earth. This provided an opportunity to study a near-Earth asteroid with a variety of instruments. Several of the telescopes at the Maui Space Surveillance System were trained at the asteroid and collected adaptive optics images, photometry and spectroscopy. Analysis of the imagery reveals the asteroid is triangular shaped with significant self-shadowing. The photometry reveals a 20-hour period and the spectros...

  4. On the Discovery of the Asteroid 3784 Chopin

    Science.gov (United States)

    Elst, E. W.

    Le 31 octobre 1986 lords d'une campagne de recherche d'asteroides a l'observatoire de Haute Provence, un asteroide de septieme magnitude fut decouvert. A l'occasion de l'opposition consecutive en 1988, l'asteroide fut observe a nouveau a l'observatoire de Haute Provence, ce qui entraina la numerotation definitive. L'asteroide recoit le numero 3874 et le nom du grand compositeur polonais, Chopin.

  5. Asteroid Redirect Mission Proximity Operations for Reference Target Asteroid 2008 EV5

    Science.gov (United States)

    Reeves, David M.; Mazanek, Daniel D.; Cichy, Benjamin D.; Broschart, Steve B.; Deweese, Keith D.

    2016-01-01

    NASA's Asteroid Redirect Mission (ARM) is composed of two segments, the Asteroid Redirect Robotic Mission (ARRM), and the Asteroid Redirect Crewed Mission (ARCM). In March of 2015, NASA selected the Robotic Boulder Capture Option1 as the baseline for the ARRM. This option will capture a multi-ton boulder, (typically 2-4 meters in size) from the surface of a large (greater than approx.100 m diameter) Near-Earth Asteroid (NEA) and return it to cis-lunar space for subsequent human exploration during the ARCM. Further human and robotic missions to the asteroidal material would also be facilitated by its return to cis-lunar space. In addition, prior to departing the asteroid, the Asteroid Redirect Vehicle (ARV) will perform a demonstration of the Enhanced Gravity Tractor (EGT) planetary defense technique2. This paper will discuss the proximity operations which have been broken into three phases: Approach and Characterization, Boulder Capture, and Planetary Defense Demonstration. Each of these phases has been analyzed for the ARRM reference target, 2008 EV5, and a detailed baseline operations concept has been developed.

  6. Asteroid Impact and Deflection Assessment mission: the Double Asteroid Redirection Test (DART)

    Science.gov (United States)

    Cheng, A.; Michel, P.

    2015-10-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission will be the first space experiment to demonstrate asteroid impact hazard mitigation by using a kinetic impactor. AIDA is a joint ESA-NASA cooperative project, which includes the ESA Asteroid Impact Mission (AIM) rendezvous spacecraft and the NASA Double Asteroid Redirection Test (DART) mission. The AIDA target is the near-Earth binary asteroid 65803 Didymos, which will make an unusually close approach to Earth in October, 2022. The ~300-kg DART spacecraft is designed to impact the Didymos secondary at 6.5 km/s and demonstrate the ability to modify its trajectory through momentum transfer. The primary goals of AIDA are (i) to investigate the binary near-Earth asteroid (65803) Didymos, (ii) to demonstrate asteroid deflection by kinetic impact and to characterize the deflection. The primary DART objectives are to demonstrate a hypervelocity impact on the Didymos moon and to determine the resulting deflection from ground-based observatories. The DART impact on the Didymos secondary will cause a measurable change in the orbital period of the binary.

  7. Frequent Nonprescription Stimulant Use and Risky Behaviors in College Students: The Role of Effortful Control

    Science.gov (United States)

    Reid, Adam M.; Graziano, Paulo A.; Balkhi, Amanda M.; McNamara, Joseph P. H.; Cottler, Linda B.; Meneses, Evander; Geffken, Gary R.

    2015-01-01

    Objective: The goal of this study was to (a) investigate the association between nonprescription stimulant use (NPSU) and risky behaviors, including risky sex, driving, financial behaviors, and drug use and (b) collect preliminary evidence on mechanisms that may link NPSU to risky behaviors. Participants: A sample of 555 college students was…

  8. Expectation and cooperation in prisoner's dilemmas: The moderating role of game riskiness.

    Science.gov (United States)

    Ng, Gary Ting Tat; Au, Wing Tung

    2016-04-01

    This paper investigated the effect of risk orientation, game riskiness, and expectation of cooperation on cooperation in one-shot prisoner's dilemmas (PD). Participants in pairs played PD games that varied on game riskiness such that for half of the games cooperation was more risky than defection (more risky games) while for another half cooperation was less risky (less risky games). They estimated how likely it was that the other player was going to cooperate (expectation of cooperation) before they made their cooperation/defection decision on each game. Supporting the Goal/Expectation Hypothesis, we replicated the effect that expectation of cooperation enhanced cooperation. We also found that risk-seeking individuals cooperated more in more risky games whereas risk-averse individuals cooperated more in less risky games. More importantly, we found that game riskiness moderated the effect of expectation of cooperation on cooperation. The positive effect of expectation of cooperation on cooperation was stronger for more risky games than for less risky games. Our results illustrated how the relation between expectation and cooperation as stipulated by the Goal/Expectation Hypothesis was moderated by riskiness of the situations.

  9. Adolescents risky MP3-player listening and its psychosocial correlates

    NARCIS (Netherlands)

    Vogel, Ineke; Brug, Johannes; van der Ploeg, Catharina P. B.; Raat, Hein

    2011-01-01

    Analogue to occupational noise-induced hearing loss, MP3-induced hearing loss may be evolving into a significant social and public health problem. To inform prevention strategies and interventions, this study investigated correlates of adolescents' risky MP3-player listening behavior primarily infor

  10. Relationship Between Methamphetamine Use and Risky Sexual Behavior in Adolescents

    Directory of Open Access Journals (Sweden)

    Cheng-Fang Yen

    2004-04-01

    Full Text Available Substance abuse and risky sexual behavior have been identified as behaviors that can endanger adolescent psychosocial development. This study examined the relationship between methamphetamine (MAMP use and risky sexual behavior in adolescents. Risky sexual behavior was compared not only between MAMP users and non-users, but also between high-frequency and low-frequency MAMP users. We compared the sexual intercourse histories of 85 adolescents formally charged as MAMP users with those of 170 gender-matched adolescents with no record of MAMP use. MAMP usage characteristics were compared between users who had and those who had not experienced sexual intercourse. Previous sexual experience was more likely in MAMP users than in non-users. MAMP users were also more likely to have had a greater total number of sexual partners and were more likely to have had unplanned sex under the influence of alcohol. High-frequency MAMP use was associated with increased tendencies to engage in unprotected sex and to use MAMP before sexual intercourse. In general, the chance of sexual intercourse increased in proportion to frequency of MAMP use. Given the clear link between MAMP use and risky sexual behavior, risk-reduction programs directed at teen MAMP users are urgently needed.

  11. Brief Report: Associations between Emotional Competence and Adolescent Risky Behavior

    Science.gov (United States)

    Hessler, Danielle M.; Katz, Lynn Fainsilber

    2010-01-01

    The current study examines associations between emotional competence (i.e., awareness, regulation, comfort with expression) and adolescent risky behavior. Children from a longitudinal study participated at age 9 and 16 (N = 88). Semi-structured interviews were conducted with children about their emotional experiences and coded for areas of…

  12. Naturalistic study of the risky situations faced by novice riders.

    Science.gov (United States)

    Aupetit, Samuel; Gallier, Virginie; Riff, Jacques; Espié, Stéphane; Delgehier, Flavien

    2016-08-01

    This article sets out to identify the typical risky situations experienced by novice motorcyclists in the real world just after licensing. The procedure consists of a follow-up of six novices during their first two months of riding with their own motorbike instrumented with cameras. The novices completed logbooks on a daily basis in order to identify the risky situations they encountered, and were given face-to-face interviews to identify the context and their shortcomings during the reported events. Data show a large number of road configurations considered as risky by the riders (248 occurrences), especially during the first two weeks. The results revealed that a lack of hazard perception skills contributed to the majority of these incidents. These situations were grouped together to form clusters of typical incident scenarios on the basis of their similarities. The most frequent scenario corresponds to a lane change in dense traffic (15% of all incidents). The discussion shows how this has enhanced our understanding of novice riders' behaviour and how the findings can improve training and licensing. Lastly, the main methodological limitations of the study and some guidelines for improving future naturalistic riding studies are presented. Practitioner Summary: This article aims to identify the risky situations of novice motorcyclists in real roads. Two hundred forty-eight events were recorded and 13 incident scenarios identified. Results revealed that a lack of hazard perception contributed to the majority of these events. The most frequent scenario corresponds to a lane change in dense traffic.

  13. Locus of control and investment in risky assets

    NARCIS (Netherlands)

    Salamanca, N.; de Grip, A.; Fouarge, D.; Montizaan, R.M.

    2013-01-01

    Using representative household panel data, we show that the investment behavior of households is related to the economic locus of control of household heads. A household's internal locus of control in economic issues is positively related to its decision to hold risky assets as well as its share of

  14. Pessimism, Trauma, Risky Sex: Covariates of Depression in College Students

    Science.gov (United States)

    Swanholm, Eric; Vosvick, Mark; Chng, Chwee-Lye

    2009-01-01

    Objective: To explain variance in depression in students (N = 648) using a model incorporating sexual trauma, pessimism, and risky sex. Method: Survey data collected from undergraduate students receiving credit for participation. Results: Controlling for demographics, a hierarchical linear regression analysis [Adjusted R[superscript 2] = 0.34,…

  15. Distortion of Probability and Outcome Information in Risky Decisions

    Science.gov (United States)

    DeKay, Michael L.; Patino-Echeverri, Dalia; Fischbeck, Paul S.

    2009-01-01

    Substantial evidence indicates that information is distorted during decision making, but very few studies have assessed the distortion of probability and outcome information in risky decisions. In two studies involving six binary decisions (e.g., banning blood donations from people who have visited England, because of "mad cow disease"),…

  16. "It Is Riskier": Preschoolers' Reasoning of Risky Situations

    Science.gov (United States)

    Nikiforidou, Zoi

    2017-01-01

    Risk is a fundamental component of well-being and is interconnected with all aspects of child development. The aim of this paper is to explore children's (N = 50) own perspectives and perceptions of risky situations. Semi-structured interviews were conducted and images were used as prompts. Children aged five to six years were asked to identify…

  17. Business & Operations

    Science.gov (United States)

    Agron, Joe

    2007-01-01

    This article presents an interview with John D. Musso, executive director of the Association of School Business Officials (ASBO) International. Musso talks about trends and issues that will most affect school business and operations in 2007 and beyond. Despite the challenges facing school operations, he believes that the key to being successful at…

  18. Determination of pole orientations and shapes of asteroids

    Science.gov (United States)

    Magnusson, Per; Barucci, M. Antonietta; Drummond, Jack D.; Lumme, Kari; Ostro, Steven J.

    1989-01-01

    The principles of asteroid light-curve inversion are discussed together with basic principles involved in approaches for deriving asteroid pole and shape parameters from photometry data. The merits of various pole determination techniques are described and compared. Results obtained so far on the pole orientations and shapes of asteroids are presented.

  19. 78 FR 51750 - NASA Asteroid Initiative Idea Synthesis Workshop

    Science.gov (United States)

    2013-08-21

    ... SPACE ADMINISTRATION NASA Asteroid Initiative Idea Synthesis Workshop AGENCY: National Aeronautics and... for the agency's Asteroid Initiative. SUMMARY: The National Aeronautics and Space Administration announces a public conference to provide a status on the Agency's Asteroid Initiative planning and to enable...

  20. 78 FR 31977 - NASA Asteroid Initiative Call for Ideas

    Science.gov (United States)

    2013-05-28

    ... SPACE ADMINISTRATION NASA Asteroid Initiative Call for Ideas AGENCY: National Aeronautics and Space... announces a public forum to provide a status on the agency's asteroid initiative planning and to encourage...: This meeting will be streamed live online. Viewing options will be posted at www.nasa.gov/asteroid...

  1. 78 FR 64253 - NASA Asteroid Initiative Idea Synthesis Workshop

    Science.gov (United States)

    2013-10-28

    ... SPACE ADMINISTRATION NASA Asteroid Initiative Idea Synthesis Workshop AGENCY: National Aeronautics and... to the recent RFI for the agency's Asteroid Initiative. SUMMARY: The National Aeronautics and Space Administration announces that the agency will resume the NASA Asteroid Initiative Idea Synthesis public...

  2. Ivar asteroid rendezvous mission system scenario and trajectory design

    Institute of Scientific and Technical Information of China (English)

    崔平远; 李立涛; 崔祜涛; 栾恩杰; 吴伟仁; 田玉龙

    2003-01-01

    The asteroid exploration opportunities are searched and calculated with launch dates in 2006 to2010, and with asteroid Ivar 1627 as the target, the spacecraft and its subsystems are designed and analyzed,and the transfer trajectory is designed using △VEGA technology for the asteroid rendezvous. The design resultssatisfied the energy requirements for small explorers.

  3. Close Approaches of Potentially Hazardous Asteroids during Two Centuries

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Asteroids are the most important small bodies in the solar system and the near-earth asteroids (NEAs) are of especial concern to the world. The reasonis that they will make close approaches to the earth in the near future. We usea reasonable dynamical model and an efficient computing method to calculate the orbits of over 160 Potentially Hazardous Asteroids (PHAs) for two centuries.

  4. Dormant Comets in the Near-Earth Asteroid Population

    NARCIS (Netherlands)

    Mommert, Michael; Harris, Alan W.; Mueller, Michael; Hora, Joseph L.; Trilling, David E.; Knight, Matthew; Bottke, William F.; Thomas, Cristina; Delbo', Marco; Emery, Josh P.; Fazio, Giovanni; Smith, Howard A.

    2015-01-01

    The population of near-Earth objects comprises active comets and asteroids, covering a wide range of dynamical parameters and physical properties. Dormant (or extinct) comets, masquerading as asteroids, have long been suspected of supplementing the near-Earth asteroid (NEA) population. We present a

  5. Rock legends the asteroids and their discoverers

    CERN Document Server

    Murdin, Paul

    2016-01-01

    This book relates the history of asteroid discoveries and christenings, from those of the early pioneering giants of Hersehel and Piazzi to modern-day amateurs. Moving from history and anecdotal information to science, the book's structure is provided by the names of the asteroids, including one named after the author. Free from a need to conform to scientific naming conventions, the names evidence hero-worship, sycophancy, avarice, vanity, whimsy, erudition and wit, revealing the human side of astronomers, especially where controversy has followed the christening. Murdin draws from extensive historical records to explore the debate over these names. Each age reveals its own biases and preferences in the naming process. < Originally regarded as “vermin of the skies,” asteroids are minor planets, rocky scraps left over from the formation of the larger planets, or broken fragments of worlds that have collided. Their scientific classification as “minor” planets makes them seem unimportant, but over th...

  6. Defining a successful commercial asteroid mining program

    Science.gov (United States)

    Andrews, Dana G.; Bonner, K. D.; Butterworth, A. W.; Calvert, H. R.; Dagang, B. R. H.; Dimond, K. J.; Eckenroth, L. G.; Erickson, J. M.; Gilbertson, B. A.; Gompertz, N. R.; Igbinosun, O. J.; Ip, T. J.; Khan, B. H.; Marquez, S. L.; Neilson, N. M.; Parker, C. O.; Ransom, E. H.; Reeve, B. W.; Robinson, T. L.; Rogers, M.; Schuh, P. M.; Tom, C. J.; Wall, S. E.; Watanabe, N.; Yoo, C. J.

    2015-03-01

    This paper summarizes a commercial Asteroid Mining Architecture synthesized by the Senior Space Design Class at the University of Washington in Winter/Spring Quarters of 2013. The main author was the instructor for that class. These results use design-to-cost development methods and focused infrastructure advancements to identify and characterize a workable space industrialization architecture including space transportation elements, asteroid exploration and mining equipment, and the earth orbit infrastructure needed to make it all work. Cost analysis predicts that for an initial investment in time and money equivalent to that for the US North Slope Oil Field, the yearly world supply of Platinum Group Metals could be increased by 50%, roughly 1500 t of LOX/LH2 propellant/year would be available in LEO, and very low cost solar panels could be assembled at GEO using asteroidal materials. The investment also would have a discounted net present value return on investment of 22% over twenty years.

  7. AIDA: the Asteroid Impact & Deflection Assessment mission

    Science.gov (United States)

    Vincent, Jean-Baptiste

    2016-07-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission is a joint cooperation between European and US space agencies that consists of two separate and independent spacecraft that will be launched to a binary asteroid system, the near-Earth asteroid Didymos, to assess the possibility of deflecting an asteroid trajectory by using a kinetic impactor. The European Asteroid Impact Mission (AIM) is under Phase A/B1 study at ESA from March 2015 until summer 2016. AIM is set to rendez-vous with the asteroid system a few months prior to the impact by the US Double Asteroid Redirection Test (DART) spacecraft to fully characterize the smaller of the two binary components. AIM is a unique mission as it will be the first time that a spacecraft will investigate the surface, subsurface, and internal properties of a small binary near Earth asteroid. In addition it will perform various important technology demonstrations that can serve other space missions: AIM will release a set of CubeSats in deep space and a lander on the surface of the smaller asteroid and for the first time, deep-space inter-satellite linking will be demonstrated between the main spacecraft, the CubeSats, and the lander, and data will also be transmitted from interplanetary space to Earth by a laser communication system. The knowledge obtained by this mission will have great implications for our understanding of the history of the Solar System. Small asteroids are believed to result from collisions and other processes (e.g., spinup, shaking) that made them what they are now. Having direct information on their surface and internal properties will allow us to understand how these processes work and transform these small bodies as well as, for this particular case, how a binary system forms. So far, our understanding of the collisional process and the validation of numerical simulations of the impact process rely on impact experiments at laboratory scales. With DART, thanks to the characterization of the

  8. The Potentially Dangerous Asteroid (101955 Bennu

    Directory of Open Access Journals (Sweden)

    I. Włodarczyk

    2014-01-01

    searching for close approaches with the earth, which can lead to possible impacts up to 2200. With the A2 nongravitational parameter in the motion of the asteroid (101955 Bennu we computed possible impact solutions using different JPL planetary and lunar ephemerides and different number of additional massive perturbed asteroids. The possible impact path of risk for 2175 is presented. Additionally, we computed possible impact solutions using the normal places method of the selection of Bennu’s astrometric observations. Moreover, we computed time evolution of the mean orbital elements and the orbital nodes of Bennu 5 kyr in the backwards and 1 kyr in the future using the Yarkovsky effects. We computed the mean motion and secular orbital resonances of the Bennu. We also computed the influence of the JPL planetary and lunar ephemerides DE403, DE405, DE406, DE414, and DE423 on the close approaches of the asteroid (101955 Bennu with the earth.

  9. Measurement of Cohesion in Asteroid Regolith Materials

    Science.gov (United States)

    Kleinhenz, Julie E.; Gaier, James R.; Waters, Deborah L.; Harvey, Ralph; Zeszut, Zoe; Carreno, Brandon; Shober, Patrick

    2017-01-01

    A study has been initiated to examine cohesive forces in asteroid materials to contribute to a better understanding of low density bodies such as asteroids and Phobos, and assist in exploration missions involving interaction with their surface material. The test specimen used in this study was a lightly weathered CM2 meteorite which is spectroscopically similar to Type C (carbonaceous) asteroids, and thought to have representative surface chemistry. To account for sample heterogeneity, adhesion forces were measured between the CM2 sample and its five primary mineral phase components. These adhesive forces bound the range of cohesive force that can be expected for the bulk material. All materials were characterized using a variety of optical and spectroscopic methods. Adhesive forces on the order of 50 to 400 µN were measured using a torsion balance in an ultrahigh vacuum chamber. The mineral samples exhibited clearly different adhesive strengths in the following hierarchy: Serpentine > Siderite > Bronzite > Olivine ˜ Fe-Ni.

  10. SNC meteorites - Evidence against an asteroidal origin

    Science.gov (United States)

    Ashwal, L. D.; Warner, J. L.; Wood, C. A.

    1982-01-01

    About 1.3 billion years ago, on one or more distant planetary bodies, silicate melts formed and produced cumulate rocks which eventually made their way to earth. Nine of these rocks have been recovered. Three distinct groups are involved, including shergottites, nakhlites, and chassignites (abbreviated as SNC). The young crystallization ages and other chemical features of SNC meteorites have prompted several workers to suggest that the specimens may be samples of igneous rock, ejected from the surface of Mars during an impact event. Others have rejected the Martian origin of SNC meteorites in favor of a more traditional asteroidal parent body. The present investigation shows that the petrologic, geochemical, and isotopic evidence is inconsistent with an asteroidal origin for SNC meteorites. It is found that the characteristics of SNC meteorites argue convincingly against their origin in a planetary object as small as the largest asteroid. That these meteorites may be fragments of the Martian surface still remains the most likely possibility.

  11. Rotational properties of the Maria asteroid family

    Science.gov (United States)

    Kim, M.; Choi, Y.; Moon, H.; Byun, Y.; Brosch, N.; Kaplan, M.; Kaynar, S.; Uysal, O.; Guzel, E.; Behrend, R.; Yoon, J.; Mottola, S.; Hellmich, S.; Hinse, T.; Eker, Z.; Park, J.

    2014-07-01

    Introduction: The Maria family is regarded as an old-type (˜3 ± 1 Gyr) [1] asteroid family which has experienced substantial collisional and dynamical evolution in the main belt. It is located near the 3:1 Jupiter mean-motion resonance area that supplies near-Earth asteroids (NEAs) to the inner Solar System. Observations: We carried out observations of Maria family asteroids in 134 nights from July 2008 to May 2013 using 0.5-m to 2-m class telescopes at seven observatories in the northern hemisphere, and derived synodic rotational periods for 51 objects, including new periods for 34 asteroids [2]. Results: We found that there is a significant excess of fast and slow rotators in the observed rotation-rate distribution. From the correlations among rotational periods, the amplitudes of lightcurves, and the sizes, we conclude that the rotational properties of the Maria family asteroids have been changed considerably by non-gravitational forces such as the YORP effect. Using the lightcurve inversion method [3,4], we successfully determined pole orientations for 13 Maria members, and found an excess of prograde spins over retrograde spins with a ratio (N_p/N_r) of 3. This implies that the retrograde rotators could have been ejected by the 3:1 resonance into the inner Solar System since the formation of the Maria family. We estimate that approximately 37 to 75 Maria family asteroids larger than 1 km have entered the near-Earth space as per 100 Myr [2].

  12. A Proposed Unified Theory of Hydrated Asteroids

    Science.gov (United States)

    Rivkin, Andrew S.

    2016-10-01

    The last decade has seen tremendous growth in the study of hydrated and hydroxylated minerals (hereafter simply called "hydrated minerals") on asteroids. Several workers have used absorptions in the 3-µm region and a correlated absorption near 0.7 µm to determine not only the presence or absence of these minerals but gain insight into the compositions of asteroid surfaces. Spectra of hundreds of asteroids have been measured and published or presented at meetings, and we are in a position to use these newer datasets to globally assess the patterns and relationships we see, as previously done by Jones et al. (1990) and Takir et al. (2012). There are several points to be addressed by any such assessment. Several different band shapes are seen in the 3-µm region, only one of which is seen in the hydrated meteorites in our collections. However, each of the main 3-µm band shapes is represented among parent bodies of collisional families. There seems to be little correlation in general between asteroid spectral class and 3-µm band shape, save for the Ch meteorites which are overwhelmingly likely to share the same band shape as the CM meteorites. Ceres has an unusual but not unique band shape, which has thus far only been found on the largest asteroids. I will present an outline scenario for the formation and evolution of hydrated asteroids, where aqueous alteration serves to lithify some objects while other objects remain unlithified and still others differentiate and suffer collisional modification. While some details will no doubt be altered to account for better or new information, this scenario is offered as a starting point for discussion.

  13. Orbital Mechanics near a Rotating Asteroid

    Indian Academy of Sciences (India)

    Yu Jiang; Hexi Baoyin

    2014-03-01

    This study investigates the different novel forms of the dynamical equations of a particle orbiting a rotating asteroid and the effective potential, the Jacobi integral, etc. on different manifolds. Nine new forms of the dynamical equations of a particle orbiting a rotating asteroid are presented, and the classical form of the dynamical equations has also been found. The dynamical equations with the potential and the effective potential in scalar form in the arbitrary body-fixed frame and the special body-fixed frame are presented and discussed. Moreover, the simplified forms of the effective potential and the Jacobi integral have been derived. The dynamical equation in coefficient-matrix form has been derived. Other forms of the dynamical equations near the asteroid are presented and discussed, including the Lagrange form, the Hamilton form, the symplectic form, the Poisson form, the Poisson-bracket form, the cohomology form, and the dynamical equations on Kähler manifold and another complex manifold. Novel forms of the effective potential and the Jacobi integral are also presented. The dynamical equations in scalar form and coefficient-matrix form can aid in the study of the dynamical system, the bifurcation, and the chaotic motion of the orbital dynamics of a particle near a rotating asteroid. The dynamical equations of a particle near a rotating asteroid are presented on several manifolds, including the symplectic manifold, the Poisson manifold, and complex manifolds, which may lead to novel methods of studying the motion of a particle in the potential field of a rotating asteroid.

  14. Asteroidal Quadruples in non Rooted Path Graphs

    Directory of Open Access Journals (Sweden)

    Gutierrez Marisa

    2015-11-01

    Full Text Available A directed path graph is the intersection graph of a family of directed subpaths of a directed tree. A rooted path graph is the intersection graph of a family of directed subpaths of a rooted tree. Rooted path graphs are directed path graphs. Several characterizations are known for directed path graphs: one by forbidden induced subgraphs and one by forbidden asteroids. It is an open problem to find such characterizations for rooted path graphs. For this purpose, we are studying in this paper directed path graphs that are non rooted path graphs. We prove that such graphs always contain an asteroidal quadruple.

  15. Capturing near-Earth asteroids around Earth

    Science.gov (United States)

    Hasnain, Zaki; Lamb, Christopher A.; Ross, Shane D.

    2012-12-01

    The list of detected near-Earth asteroids (NEAs) is constantly growing. NEAs are likely targets for resources to support space industrialization, as they may be the least expensive source of certain needed raw materials. The limited supply of precious metals and semiconducting elements on Earth may be supplemented or even replaced by the reserves floating in the form of asteroids around the solar system. Precious metals make up a significant fraction NEAs by mass, and even one metallic asteroid of ˜1km size and fair enrichment in platinum-group metals would contain twice the tonnage of such metals already harvested on Earth. There are ˜1000 NEAs with a diameter of greater than 1 km. Capturing these asteroids around the Earth would expand the mining industry into an entirely new dimension. Having such resources within easy reach in Earth's orbit could provide an off-world environmentally friendly remedy for impending terrestrial shortages, especially given the need for raw materials in developing nations. In this paper, we develop and implement a conceptually simple algorithm to determine trajectory characteristics necessary to move NEAs into capture orbits around the Earth. Altered trajectories of asteroids are calculated using an ephemeris model. Only asteroids of eccentricity less than 0.1 have been studied and the model is restricted to the ecliptic plane for simplicity. We constrain the time of retrieval to be 10 years or less, based on considerations of the time to return on investment. For the heliocentric phase, constant acceleration is assumed. The acceleration required for transporting these asteroids from their undisturbed orbits to the sphere of influence of the Earth is the primary output, along with the impulse or acceleration necessary to effect capture to a bound orbit once the Earth's sphere of influence is reached. The initial guess for the constant acceleration is provided by a new estimation method, similar in spirit to Edelbaum's. Based on the

  16. Asteroid families - Physical properties and evolution

    Science.gov (United States)

    Chapman, Clark R.; Paolicchi, Paolo; Zappala, Vincenzo; Binzel, Richard P.; Bell, Jeffrey F.

    1989-01-01

    Asteroid families are considered to be fragments from collisional destruction of precursor bodies. However, results available on the inferred mineralogy, size distributions, and spins of family members do not confirm the expectations of the traditional model. Only a handful of nearly 100 proposed families, most of them populous, have distributions of inferred mineralogies consistent with simple cosmochemical models for parent bodies. It is suggested that most catastrophic collisions may not result in observable families, but rather in a spray of smaller particles, thus accounting for the small number of confirmed and consistent families, despite evidence for extensive collisional evolution of asteroids.

  17. Collisional evolution of the early asteroid belt

    Science.gov (United States)

    Gil-Hutton, Ricardo; Brunini, Adrián

    1999-04-01

    We present numerical results obtained by a simulation of the collisional process between asteroids and scattered comets from the Uranus-Neptune zone. This mechanism allows the use of single exponent incremental size distributions for the initial belt reaching a final distribution that matches the observed population very well. Since the cometary bombardment was extremely efficient removing mass from the primordial asteroid belt in a very short time, we always obtained belts with total masses less than 0.001 M ⊕ after ≈ 2×10 7 yrs. This result allows processes with an important initial mass preserving Vestas basaltic crust.

  18. Gravitational Capture of Asteroids by Gas Drag

    Directory of Open Access Journals (Sweden)

    E. Vieira Neto

    2009-01-01

    captured by the planet got its velocity reduced and could been trapped as an irregular satellite. It is well known that, depending on the time scale of the gas envelope, an asteroid will spiral and collide with the planet. So, we simulate the passage of the asteroid in the gas envelope with its density decreasing along the time. Using this approach, we found effective captures, and have a better understanding of the whole process. Finally, we conclude that the origin of the irregular satellites cannot be attributed to the gas drag capture mechanism alone.

  19. Manuel′s asteroid disruption technique

    Directory of Open Access Journals (Sweden)

    Manuel John

    2015-01-01

    Full Text Available A seventy-year-old male presented with dense asteroid hyalosis in both eyes. He had undergone cataract extraction in one eye 3 years ago, and the other eye had immature cataract. Both the autorefractor and dilated streak retinoscopy did not give readings and subjective visual improvement could not be achieved. Immediately following YAG posterior capsulotomy and anterior vitreous asteroid disruption, the vision improved to 20/20 with recordable auto refractor and streak retinoscopy values. Our initial experience indicates that the treatment is simple, safe and effective but needs controlled and prospective studies to confirm its long-term safety.

  20. NASA's Asteroid Redirect Mission: Overview and Status

    Science.gov (United States)

    Abell, Paul; Gates, Michele; Johnson, Lindley; Chodas, Paul; Brophy, John; Mazanek, Dan; Muirhead, Brian

    A major element of the National Aeronautics and Space Administration’s (NASA) new Asteroid Initiative is the Asteroid Redirect Mission (ARM). This concept was first proposed in 2011 during a feasibility study at the Keck Institute for Space Studies (KISS)[1] and is under consideration for implementation by NASA. The ARM involves sending a high-efficiency (ISP 3000 s), high-power (40 kW) solar electric propulsion (SEP) robotic vehicle that leverages technology developed by NASA’s Space Technology Mission Directorate (STMD) to rendezvous with a near-Earth asteroid (NEA) and return asteroidal material to a stable lunar distant retrograde orbit (LDRO)[2]. There are two mission concepts currently under study, one that captures an entire 7 - 10 meter mean diameter NEA[3], and another that retrieves a 1 - 10 meter mean diameter boulder from a 100+ meter class NEA[4]. Once the retrieved asteroidal material is placed into the LDRO, a two person crew would launch aboard an Orion capsule to rendezvous and dock with the robotic SEP vehicle. After docking, the crew would conduct two extra-vehicular activities (EVA) to collect asteroid samples and deploy instruments prior to Earth return. The crewed portion of the mission is expected to last approximately 25 days and would represent the first human exploration mission beyond low-Earth orbit (LEO) since the Apollo program. The ARM concept leverages NASA’s activities in Human Exploration, Space Technology, and Planetary Defense to accomplish three primary objectives and several secondary objectives. The primary objective relevant to Human Exploration is to gain operational experience with vehicles, systems, and components that will be utilized for future deep space exploration. In regard to Space Technology, the ARM utilizes advanced SEP technology that has high power and long duration capabilities that enable future missions to deep space destinations, such as the Martian system. With respect to Planetary Defense, the ARM

  1. Achieving optimal business performance through business practices ...

    African Journals Online (AJOL)

    Achieving optimal business performance through business practices: ... it is often articulated that best business practices produce superlative business performance. ... strategic planning practices, human resource management practices, risk ...

  2. Failure mode diagram of rubble pile asteroids: Application to (25143) asteroid Itokawa

    Science.gov (United States)

    Hirabayashi, Masatoshi; Scheeres, Daniel J.

    2016-01-01

    Proposing a diagram which shows the variation in asteroidal failure as a function of a spin period, later called the failure mode diagram, this paper considers the failure modes and conditions of asteroid (25143) Itokawa. This diagram is useful to describe when and where failure occurs in an asteroid. Assuming that Itokawa is homogeneous, we use a plastic finite element code to obtain the diagram for this object. The results show that if the bulk cohesive strength is less than 0.1 Pa, Itokawa experiences compressional failure on the neck surface at the current spin period 12.1 hours. At a spin period shorter than 4.5 hours, tension across the neck causes this asteroid to split into two components. It is also found that if the breakup spin period is longer than 5.2 hours, their motion is bounded. This implies that once Itokawa splits, the components may escape from one another.

  3. Hungaria asteroid region telescopic spectral survey (HARTSS) I: Stony asteroids abundant in the Hungaria background population

    Science.gov (United States)

    Lucas, Michael P.; Emery, Joshua P.; Pinilla-Alonso, Noemi; Lindsay, Sean S.; Lorenzi, Vania

    2017-07-01

    The Hungaria asteroids remain as survivors of late giant planet migration that destabilized a now extinct inner portion of the primordial asteroid belt and left in its wake the current resonance structure of the Main Belt. In this scenario, the Hungaria region represents a ;purgatory; for the closest, preserved samples of the asteroidal material from which the terrestrial planets accreted. Deciphering the surface composition of these unique samples may provide constraints on the nature of the primordial building blocks of the terrestrial planets. We have undertaken an observational campaign entitled the Hungaria Asteroid Region Telescopic Spectral Survey (HARTSS) to record near-infrared (NIR) reflectance spectra in order to characterize their taxonomy, surface mineralogy, and potential meteorite analogs. The overall objective of HARTSS is to evaluate the compositional diversity of asteroids located throughout the Hungaria region. This region harbors a collisional family of Xe-type asteroids, which are situated among a background (i.e., non-family) of predominantly S-complex asteroids. In order to assess the compositional diversity of the Hungaria region, we have targeted background objects during Phase I of HARTSS. Collisional family members likely reflect the composition of one original homogeneous parent body, so we have largely avoided them in this phase. We have employed NIR instruments at two ground-based telescope facilities: the NASA Infrared Telescope Facility (IRTF), and the Telescopio Nazionale Galileo (TNG). Our data set includes the NIR spectra of 42 Hungaria asteroids (36 background; 6 family). We find that stony S-complex asteroids dominate the Hungaria background population (29/36 objects; ∼80%). C-complex asteroids are uncommon (2/42; ∼5%) within the Hungaria region. Background S-complex objects exhibit considerable spectral diversity as band parameter measurements of diagnostic absorption features near 1- and 2-μm indicate that several

  4. Sensitivity of the Asteroid Redirect Robotic Mission (ARRM) to Launch Date and Asteroid Stay Time

    Science.gov (United States)

    Mcguire, Melissa L.; Burke, Laura M.; McCarty, Steven L.; Strange, Nathan J.; Qu, Min; Shen, Haijun; Vavrina, Matthew A.

    2017-01-01

    National Aeronautics and Space Administrations (NASAs) proposed Asteroid Redirect Mission (ARM) is being designed to robotically capture and then redirect an asteroidal boulder mass into a stable orbit in the vicinity of the moon, where astronauts would be able to visit and study it. The current reference trajectory for the robotic portion, ARRM, assumes a launch on a Delta IV H in the end of the calendar year 2021, with a return for astronaut operations in cislunar space in 2026. The current baseline design allocates 245 days of stay time at the asteroid for operations and boulder collection. This paper outlines analysis completed by the ARRM mission design team to understand the sensitivity of the reference trajectory to launch date and asteroid stay time.

  5. Business Law

    DEFF Research Database (Denmark)

    Föh, Kennet Fischer; Mandøe, Lene; Tinten, Bjarke

    Business Law is a translation of the 2nd edition of Erhvervsjura - videregående uddannelser. It is an educational textbook for the subject of business law. The textbook covers all important topic?s within business law such as the Legal System, Private International Law, Insolvency Law, Contract law......, Instruments of debt and other claims, Sale of Goods and real estate, Charges, mortgages and pledges, Guarantees, Credit agreements, Tort Law, Product liability and Insurance, Company law, Market law, Labour Law, Family Law and Law of Inheritance....

  6. Business Anthropology

    DEFF Research Database (Denmark)

    Moeran, Brian

    2015-01-01

    This essay outlines the overall scope and location of business anthropology within the overall field of the discipline. It outlines its foundations as an applied form of anthropology in early developments in the United States (in particular, in Western Electric's Hawthorne Project and the Human...... what a future program for business anthropology might look like and suggests four areas for theoretical development against a background of education, engagement, and comparative work. These are an examination of structures of power in, between, and dependent on business organizations of all kinds...

  7. Tidal stress and failure in the moon of binary asteroid systems: Application to asteroid (65803) Didymos

    Science.gov (United States)

    Sophal Pou, Laurent; Garcia, Raphael F.; Mimoun, David; Murdoch, Naomi; Karatekin, Ozgur

    2017-04-01

    Rocky remnants left over from the early formation of the Solar System, asteroids are a target of choice for planetary science since much about the history of planetary formation and small body evolution processes can be learnt by studying them. Here we consider the case of the binary asteroid (65803) Didymos, the target of several mission proposals e.g., AIM [1] and DART [2]. A mission to Didymos would be a great opportunity for in-situ geophysical investigation, providing information on the surface and interior of asteroids. Such studies would improve our knowledge of binary asteroid formation and subsequent evolution of asteroids, thus of the history of the Solar System. As Didymos is a binary asteroid [3] with the main 800-meter diameter asteroid named Didymain and a 150-meter sized moon named Didymoon, both are subject to tidal stress. Recent investigations suggest that Didymoon is tidally locked and moves in a retrograde motion around Didymain along an elliptic orbit with a 0.03 eccentricity at most. In the case of an eccentric orbit, the tidal stress varies periodically and may be strong enough to cause tidal quakes on Didymoon at some points of the orbit. For this study, we modelled Didymoon as a spherical, layered body with different internal structures: a homogeneous model, and two models with a 1-meter and 10-meter regolith layer on top of a stronger internal core. Simulations show that, for a cohesionless body with an internal friction angle of 30°, tidal stress is strong enough to cause failure at the surface of Didymoon. A maximal stress is reached around the poles and for a mean anomaly of 90°. These results would mean that if tidal quakes occur on Didymoon, then they are likely to happen at these locations. An extension of these results to an ellipsoidal model of Didymoon is also presented for comparison with the spherical case and for application to other bodies. [1]: P. Michel et al., Science case for the asteroid impact mission (aim): A

  8. Seven Near-Earth Asteroids at Asteroids Observers (OBAS) - MPPD: 2016 June-November

    Science.gov (United States)

    Lozano, Juan; Flores, Angel; Mas, Vicente; Fornas, Gonzalo; Rodrigo, Onofre; Brines, Pedro; Forna, Alvaro; Herrero, David; Carreño, Alfonso; Arce, Enrique

    2017-04-01

    We report on the results of photometric analysis on seven near-Earth asteroids (NEA) by Asteroides Observers (OBAS). This work is part of the Minor Planet Photometric Database effort that was initiated by a group of Spanish amateur astronomers. We have managed to obtain a number of accurate and complete lightcurves as well as some additional incomplete lightcurves to help analysis at future oppositions.

  9. Hungaria Asteroid Region Telescopic Spectral Survey (HARTSS): Stony Asteroids Abundant in the Background and Family Populations

    Science.gov (United States)

    Lucas, Michael P.; Emery, Joshua P.; Pinilla-Alonso, Noemi; Lindsay, Sean S.; Lorenzi, Vania

    2016-10-01

    The Hungaria region represents a "purgatory" for the closest, preserved samples of the material from which the terrestrial planets accreted. The Hungaria region harbors a collisional family of Xe-type asteroids, which are situated among a background of predominantly S-complex asteroids. Deciphering their surface composition may provide constraints on the nature of the primordial building blocks of the terrestrial planets. We hypothesize that planetesimals in the inner part of the primordial asteroid belt experienced partial- to full-melting and differentiation, the Hungaria region should retain any petrologically-evolved material that formed there.We have undertaken an observational campaign entitled the Hungaria Asteroid Region Telescopic Spectral Survey (HARTSS) to record near-infrared (NIR) spectra to characterize taxonomy, surface mineralogy, and potential meteorite analogs. We used NIR instruments at two ground-based facilities (NASA IRTF; TNG). Our data set includes spectra of 82 Hungaria asteroids (61 background; 21 family), 65 were observed during HARTSS. We compare S-complex background asteroids to calibrations developed via laboratory analyses of ordinary chondrites, and to our analyses (EPMA, XRD, VIS+NIR spectra) of 11 primitive achondrite (acapulcoite-lodranite clan) meteorites.We find that stony S-complex asteroids dominate the Hungaria background population (~80%). Background objects exhibit considerable spectral diversity, when quantified by spectral band parameter measurements, translates to a variety of surface compositions. Two main meteorite groups are represented within the Hungaria background: unmelted, nebular L chondrites (and/or L chondrites), and partially-melted primitive achondrites. H-chondrite mineralogies appear to be absent from the Hungaria background. Xe-type Hungaria family members exhibit spectral homogeneity, consistent with the hypothesis that the family was derived from the disruption of a parent body analogous to an enstatite

  10. Twenty-one Asteroid Lightcurves at Group Observadores de Asteroides (OBAS): Late 2015 to Early 2016

    Science.gov (United States)

    Aznar Macias, Amadeo; Carreno Garcerain, Alfonso; Arce Masego, Enrique; Brines Rodriguez, Pedro; Lozano de Haro, Juan; Fornas Silva, Alvaro; Fornas Silva, Gonzalo; Mas Martinez, Vicente; Rodrigo Chiner, Onofre; Herrero Porta, David

    2016-07-01

    We report on the photometric analysis result of 21 mainbelt asteroids (MBA) done by Observadores de Asteroides (OBAS). This work is part of the Minor Planet Photometric Database task initiated by a group of Spanish amateur astronomers. We have managed to obtain a number of accurate and complete lightcurves as well as additional incomplete lightcurves to help analysis at future oppositions. This is a compilation of lightcurves obtained during last quarter of 2015 and first quarter of 2016.

  11. Asteroid mass estimation using Markov-Chain Monte Carlo techniques

    Science.gov (United States)

    Siltala, Lauri; Granvik, Mikael

    2016-10-01

    Estimates for asteroid masses are based on their gravitational perturbations on the orbits of other objects such as Mars, spacecraft, or other asteroids and/or their satellites. In the case of asteroid-asteroid perturbations, this leads to a 13-dimensional inverse problem where the aim is to derive the mass of the perturbing asteroid and six orbital elements for both the perturbing asteroid and the test asteroid using astrometric observations. We have developed and implemented three different mass estimation algorithms utilizing asteroid-asteroid perturbations into the OpenOrb asteroid-orbit-computation software: the very rough 'marching' approximation, in which the asteroid orbits are fixed at a given epoch, reducing the problem to a one-dimensional estimation of the mass, an implementation of the Nelder-Mead simplex method, and most significantly, a Markov-Chain Monte Carlo (MCMC) approach. We will introduce each of these algorithms with particular focus on the MCMC algorithm, and present example results for both synthetic and real data. Our results agree with the published mass estimates, but suggest that the published uncertainties may be misleading as a consequence of using linearized mass-estimation methods. Finally, we discuss remaining challenges with the algorithms as well as future plans, particularly in connection with ESA's Gaia mission.

  12. Asteroid modeling for testing spacecraft approach and landing.

    Science.gov (United States)

    Martin, Iain; Parkes, Steve; Dunstan, Martin; Rowell, Nick

    2014-01-01

    Spacecraft exploration of asteroids presents autonomous-navigation challenges that can be aided by virtual models to test and develop guidance and hazard-avoidance systems. Researchers have extended and applied graphics techniques to create high-resolution asteroid models to simulate cameras and other spacecraft sensors approaching and descending toward asteroids. A scalable model structure with evenly spaced vertices simplifies terrain modeling, avoids distortion at the poles, and enables triangle-strip definition for efficient rendering. To create the base asteroid models, this approach uses two-phase Poisson faulting and Perlin noise. It creates realistic asteroid surfaces by adding both crater models adapted from lunar terrain simulation and multiresolution boulders. The researchers evaluated the virtual asteroids by comparing them with real asteroid images, examining the slope distributions, and applying a surface-relative feature-tracking algorithm to the models.

  13. Asteroid models from the Lowell Photometric Database

    CERN Document Server

    Durech, J; Oszkiewicz, D; Vanco, R

    2016-01-01

    We use the lightcurve inversion method to derive new shape models and spin states of asteroids from the sparse-in-time photometry compiled in the Lowell Photometric Database. To speed up the time-consuming process of scanning the period parameter space through the use of convex shape models, we use the distributed computing project Asteroids@home, running on the Berkeley Open Infrastructure for Network Computing (BOINC) platform. This way, the period-search interval is divided into hundreds of smaller intervals. These intervals are scanned separately by different volunteers and then joined together. We also use an alternative, faster, approach when searching the best-fit period by using a model of triaxial ellipsoid. By this, we can independently confirm periods found with convex models and also find rotation periods for some of those asteroids for which the convex-model approach gives too many solutions. From the analysis of Lowell photometric data of the first 100,000 numbered asteroids, we derived 328 new ...

  14. Spectroscopic Survey of X-type Asteroids

    CERN Document Server

    Fornasier, Sonia; Dotto, Elisabetta

    2011-01-01

    We present reflected light spectral observations from 0.4 to 2.5 micron of 24 asteroids chosen from the population of asteroids initially classified as Tholen X-type objects (Tholen, 1984). The X complex in the Tholen taxonomy comprises the E, M and P classes which have very different inferred mineralogies but which are spectrally similar to each other, with featureless spectra in visible wavelengths. The data were obtained during several observing runs in the 2004-2007 years at the NTT, TNG and IRTF telescopes. We find a large variety of near-infrared spectral behaviors within the X class, and we identify weak absorption bands in spectra of 11 asteroids. Our spectra, together with albedos published by Tedesco et al. (2002), can be used to suggest new Tholen classifications for these objects. In order to constrain the possible composition of these asteroids, we perform a least-squares search through the RELAB spectral database. Many of the best fits are consistent with meteorite analogue materials suggested i...

  15. Comet nucleus and asteroid sample return missions

    Science.gov (United States)

    1992-01-01

    Three Advanced Design Projects have been completed this academic year at Penn State. At the beginning of the fall semester the students were organized into eight groups and given their choice of either a comet nucleus or an asteroid sample return mission. Once a mission had been chosen, the students developed conceptual designs. These were evaluated at the end of the fall semester and combined into three separate mission plans, including a comet nucleus same return (CNSR), a single asteroid sample return (SASR), and a multiple asteroid sample return (MASR). To facilitate the work required for each mission, the class was reorganized in the spring semester by combining groups to form three mission teams. An integration team consisting of two members from each group was formed for each mission so that communication and information exchange would be easier among the groups. The types of projects designed by the students evolved from numerous discussions with Penn State faculty and mission planners at the Johnson Space Center Human/Robotic Spacecraft Office. Robotic sample return missions are widely considered valuable precursors to manned missions in that they can provide details about a site's environment and scientific value. For example, a sample return from an asteroid might reveal valuable resources that, once mined, could be utilized for propulsion. These missions are also more adaptable when considering the risk to humans visiting unknown and potentially dangerous locations, such as a comet nucleus.

  16. Rotation Properties of Small Jovian Trojan Asteroids

    Science.gov (United States)

    French, Linda M.; Stephens, Robert D.; James, David; Coley, Daniel R.; Warner, Brian D.; Rohl, Derrick

    2016-10-01

    Jovian Trojan asteroids are of interest both as objects in their own right (we have no spectral analogs among meteorite samples) and as possible relics of Solar System formation. Asteroid lightcurves can give information about processes that have affected a group of asteroids; they can also give information about the density of the objects when enough lightcurves have been collected. We have been carrying out a survey of Trojan lightcurve properties for comparison with small asteroids and with comets. In a recent paper (French et al. 2015) we presented evidence that a significant number of Trojans have rotation periods greater than 24 hours. We will report our latest results and compare them with results of sparsely-sampled lightcurves from the Palomar Transient Factory (Waszczak et al. 2015). LF, RS, and DR were visiting astronomers at Cerro Tololo Interamerican Observatory, operated by AURA under contract with the NSF, and with the SMARTS Consortium at CTIO. This research was sponsored by NSF Planetary Astronomy grant 1212115.ReferencesFrench, L.M. et al. 2015. Icarus 254, pp. 1-17.Waszczak, A. et al. 2015. A.J. 150, Issue 3, I.D. 35.

  17. NASA hits back in asteroid spat

    Science.gov (United States)

    Cartlidge, Edwin

    2016-07-01

    Nathan Myhrvold, chief executive of the company Intellectual Ventures and a former chief technology officer of Microsoft, is at loggerheads with a group of NASA astrophysicists over the latter's ability to accurately measure the properties of tens of thousands of asteroids in the solar system.

  18. A note on cement in asteroids

    CERN Document Server

    Bilalbegovic, G

    2016-01-01

    Cement mineral tobermorite was formed in hydrothermal experiments on alternation of calcium-aluminum-rich inclusions (CAIs) in carbonaceous chondrite meteorites. Unidentified bands at 14 microns were measured for CAIs and the matrix of the Allende meteorite sample, as well as for Hektor and Agamemnon asteroids. The presence of cement nanoparticles may explain the feature at 14 microns.

  19. Asteroid-Generated Tsunami and Impact Risk

    Science.gov (United States)

    Boslough, M.; Aftosmis, M.; Berger, M. J.; Ezzedine, S. M.; Gisler, G.; Jennings, B.; LeVeque, R. J.; Mathias, D.; McCoy, C.; Robertson, D.; Titov, V. V.; Wheeler, L.

    2016-12-01

    The justification for planetary defense comes from a cost/benefit analysis, which includes risk assessment. The contribution from ocean impacts and airbursts is difficult to quantify and represents a significant uncertainty in our assessment of the overall risk. Our group is currently working toward improved understanding of impact scenarios that can generate dangerous tsunami. The importance of asteroid-generated tsunami research has increased because a new Science Definition Team, at the behest of NASA's Planetary Defense Coordinating Office, is now updating the results of a 2003 study on which our current planetary defense policy is based Our group was formed to address this question on many fronts, including asteroid entry modeling, tsunami generation and propagation simulations, modeling of coastal run-ups, inundation, and consequences, infrastructure damage estimates, and physics-based probabilistic impact risk assessment. We also organized the Second International Workshop on Asteroid Threat Assessment, focused on asteroid-generated tsunami and associated risk (Aug. 23-24, 2016). We will summarize our progress and present the highlights of our workshop, emphasizing its relevance to earth and planetary science. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under Contract DE-AC04-94AL85000.

  20. Spectroscopic survey of M--type asteroids

    CERN Document Server

    Fornasier, S; Dotto, E; Migliorini, A; Ockert-Bell, M; Barucci, M A

    2010-01-01

    M-type asteroids, as defined in the Tholen taxonomy (Tholen, 1984), are medium albedo bodies supposed to have a metallic composition and to be the progenitors both of differentiated iron-nickel meteorites and enstatite chondrites. We carried out a spectroscopic survey in the visible and near infrared wavelength range (0.4-2.5 micron) of 30 asteroids chosen from the population of asteroids initially classified as Tholen M -types, aiming to investigate their surface composition. The data were obtained during several observing runs during the years 2004-2007 at the TNG, NTT, and IRTF telescopes. We computed the spectral slopes in several wavelength ranges for each observed asteroid, and we searched for diagnostic spectral features. We confirm a large variety of spectral behaviors for these objects as their spectra are extended into the near-infrared, including the identification of weak absorption bands, mainly of the 0.9 micron band tentatively attributed to orthopyroxene, and of the 0.43 micron band that may b...

  1. Asteroid Risk Assessment: A Probabilistic Approach.

    Science.gov (United States)

    Reinhardt, Jason C; Chen, Xi; Liu, Wenhao; Manchev, Petar; Paté-Cornell, M Elisabeth

    2016-02-01

    Following the 2013 Chelyabinsk event, the risks posed by asteroids attracted renewed interest, from both the scientific and policy-making communities. It reminded the world that impacts from near-Earth objects (NEOs), while rare, have the potential to cause great damage to cities and populations. Point estimates of the risk (such as mean numbers of casualties) have been proposed, but because of the low-probability, high-consequence nature of asteroid impacts, these averages provide limited actionable information. While more work is needed to further refine its input distributions (e.g., NEO diameters), the probabilistic model presented in this article allows a more complete evaluation of the risk of NEO impacts because the results are distributions that cover the range of potential casualties. This model is based on a modularized simulation that uses probabilistic inputs to estimate probabilistic risk metrics, including those of rare asteroid impacts. Illustrative results of this analysis are presented for a period of 100 years. As part of this demonstration, we assess the effectiveness of civil defense measures in mitigating the risk of human casualties. We find that they are likely to be beneficial but not a panacea. We also compute the probability-but not the consequences-of an impact with global effects ("cataclysm"). We conclude that there is a continued need for NEO observation, and for analyses of the feasibility and risk-reduction effectiveness of space missions designed to deflect or destroy asteroids that threaten the Earth. © 2015 Society for Risk Analysis.

  2. Asteroid thermal modeling: recent developments and applications

    NARCIS (Netherlands)

    Harris, A. W.; Mueller, M.

    2006-01-01

    A variety of thermal models are used for the derivation of asteroid physical parameters from thermal-infrared observations Simple models based on spherical geometry are often adequate for obtaining sizes and albedos when very little information about an object is available However sophisticated ther

  3. A note on cement in asteroids

    Science.gov (United States)

    Bilalbegović, G.

    2016-09-01

    Cement mineral tobermorite was formed in hydrothermal experiments on alternation of calcium-aluminum-rich inclusions (CAIs) in carbonaceous chondrite meteorites. Unidentified bands at 14 μm were measured for CAIs and the matrix of the Allende meteorite sample, as well as for Hektor and Agamemnon asteroids. The presence of cement nanoparticles may explain the feature at 14 μm.

  4. Asteroid thermal modeling: recent developments and applications

    NARCIS (Netherlands)

    Harris, A. W.; Mueller, M.

    2006-01-01

    A variety of thermal models are used for the derivation of asteroid physical parameters from thermal-infrared observations Simple models based on spherical geometry are often adequate for obtaining sizes and albedos when very little information about an object is available However sophisticated

  5. Early formation of evolved asteroidal crust.

    Science.gov (United States)

    Day, James M D; Ash, Richard D; Liu, Yang; Bellucci, Jeremy J; Rumble, Douglas; McDonough, William F; Walker, Richard J; Taylor, Lawrence A

    2009-01-08

    Mechanisms for the formation of crust on planetary bodies remain poorly understood. It is generally accepted that Earth's andesitic continental crust is the product of plate tectonics, whereas the Moon acquired its feldspar-rich crust by way of plagioclase flotation in a magma ocean. Basaltic meteorites provide evidence that, like the terrestrial planets, some asteroids generated crust and underwent large-scale differentiation processes. Until now, however, no evolved felsic asteroidal crust has been sampled or observed. Here we report age and compositional data for the newly discovered, paired and differentiated meteorites Graves Nunatak (GRA) 06128 and GRA 06129. These meteorites are feldspar-rich, with andesite bulk compositions. Their age of 4.52 +/- 0.06 Gyr demonstrates formation early in Solar System history. The isotopic and elemental compositions, degree of metamorphic re-equilibration and sulphide-rich nature of the meteorites are most consistent with an origin as partial melts from a volatile-rich, oxidized asteroid. GRA 06128 and 06129 are the result of a newly recognized style of evolved crust formation, bearing witness to incomplete differentiation of their parent asteroid and to previously unrecognized diversity of early-formed materials in the Solar System.

  6. Asteroids Lightcurves Analysis: 2015 October-December

    Science.gov (United States)

    Carbognani, Albino; Buzzi, Luca

    2016-04-01

    Eight asteroids, main-belt (MBA) and near-Earth (NEA), were observed in 2015 Oct-Dec: 6853 Silvanomassaglia, (112985) 2002 RS28, (155110) 2005 TB, (163899) 2003 SD220, (253106) 2002 UR3, (337866) 2001 WL15, 2015 XC, and 2015 WG9.

  7. Collisional Excavation of Asteroid (596) Scheila

    CERN Document Server

    Bodewits, D; Li, J -Y; Landsman, W B; Besse, S; A'Hearn, M F

    2011-01-01

    We observed asteroid (596) Scheila and its ejecta cloud using the Swift UV-optical telescope. We obtained photometry of the nucleus and the ejecta, and for the first time measured the asteroid's reflection spectrum between 290 - 500 nm. Our measurements indicate significant reddening at UV wavelengths (13% per 1000 {\\AA}) and a possible broad, unidentified absorption feature around 380 nm. Our measurements indicate that the outburst has not permanently increased the asteroid's brightness. We did not detect any of the gases that are typically associated with either hypervolatile activity thought responsible for cometary outbursts (CO+, CO2+), or for any volatiles excavated with the dust (OH, NH, CN, C2, C3). We estimate that 6 x 10^8 kg of dust was released with a high ejection velocity of 57 m/s (assuming 1 {\\mu}m sized particles). While the asteroid is red in color and the ejecta have the same color as the Sun, we suggest that the dust does not contain any ice. Based on our observations, we conclude that (59...

  8. Business Anthropology

    DEFF Research Database (Denmark)

    Moeran, Brian

    2015-01-01

    This essay outlines the overall scope and location of business anthropology within the overall field of the discipline. It outlines its foundations as an applied form of anthropology in early developments in the United States (in particular, in Western Electric's Hawthorne Project and the Human...... Relations School at Harvard University), as well as in the United Kingdom and elsewhere, before turning to five areas of research and practice: academic ethnographies of business practices, regional studies, case studies developed by practitioners, theoretical applications, and methods. The essay then asks...... what a future program for business anthropology might look like and suggests four areas for theoretical development against a background of education, engagement, and comparative work. These are an examination of structures of power in, between, and dependent on business organizations of all kinds...

  9. The Advanced Jovian Asteroid Explorer (AJAX)

    Science.gov (United States)

    Murchie, S. L.; Adams, E. Y.; Mustard, J. F.; Rivkin, A.; Peplowski, P. N.

    2015-12-01

    The Advanced Jovian Asteroid eXplorer (AJAX) is the first mission to characterize the geology, morphology, geophysical properties, and chemistry of a Trojan asteroid. The Decadal Survey outlined a notional New Frontiers class Trojan asteroid rendezvous mission to conduct geological, elemental composition, mineralogical, and geophysical investigations. AJAX, our Discovery mission proposal, addresses the Decadal Survey science goals by using a focused payload and an innovative mission design. By responding to the most important questions about the Trojan asteroids, AJAX advances our understanding of all of the Solar System. Are these objects a remnant population of the local primordial material from which the outer planets and their satellites formed, or did they originate in the Kuiper Belt? Landed measurements of major and minor elements test hypotheses for the Trojan asteroid origin, revealing the outer Solar System dynamical history. How and when were prebiotic materials delivered to the terrestrial planets? AJAX's landed measurements include C and H concentrations, necessary to determine their inventories of volatiles and organic compounds, material delivered to the inner Solar System during the Late Heavy Bombardment. What chemical and geological processes shaped the small bodies that merged to form the planets in our Solar System? AJAX investigates the asteroid internal structure, geology, and regolith by using global high-resolution stereo and multispectral imaging, determining density and estimating interior porosity by measuring gravity, and measuring regolith mechanical properties by landing. AJAX's science phase starts with search for natural satellites and dust lifted by possible cometary activity and shape and pole position determination. AJAX descends to lower altitudes for global mapping, and conducts a low flyover for high-resolution surface characterization and measurement of hydrogen abundance. Finally, it deploys a small landed package, which

  10. Reducing the Asteroid and Comet Impact Hazard

    Science.gov (United States)

    Crawford, David

    1998-10-01

    Of the 140 impact craters known on the surface of Earth, the most famous was created about 65 million years ago when a 10 km asteroid or comet came down in shallow water near the present day town of Chicxulub, Mexico. With a kinetic energy equivalent to 100 trillion tons of TNT, the impact event lofted enough debris onto globe-straddling trajectories to flash heat much of the surface of the Earth and then darken the skies for several years. Numerous investigations have demonstrated that such an event, which happens, on average, every 100 million years, caused extreme stress on Earth's climate and most likely led to the extinction of many species. Computational simulations demonstrate that more numerous asteroids or comets as small as 1 km in diameter, impacting, on average, every 300,000 years may be globally catastrophic. Indeed, the odds of an individual dying from a relatively frequent 1 km impacting object (about 1 in 10,000) are substantially greater than from the impact of an infrequent dinosaur killer (1 in 1,000,000). What can we do to reduce the hazard from impacting comets and asteroids? First, we should find what's out there with our name on it. Only about 10 percent of the potential Earth-crossing asteroids have been found. Even at the greatly increased detection rate of recent years, it will be several decades before we've found 90 percent of the Earth-crossers. Second, we should learn everything we can about the physical, compositional and mechanical properties of asteroids and comets. A recent computational study demonstrated that weakly bound asteroids (little more than rubble piles) are easier to break than deflect(E. Asphaug, S. J. Ostro, R. S. Hudson, D. J. Scheeres and W. Benz (1998), Nature, Vol. 393, pp. 437-440.). Is this an advantage or disadvantage? Third, we should study potential means of mitigating the hazard by deflecting the object while still in space or evacuating affected regions (such as coastlines) of the Earth. Because the

  11. 3-µm Spectroscopy of Asteroid 16 Psyche

    Science.gov (United States)

    Takir, Driss; Reddy, Vishnu; Sanchez, Juan; Shepard, Michael K.

    2016-10-01

    Asteroid 16 Psyche, an M-type asteroid, is thought to be one of the most massive exposed iron metal object in the asteroid belt. The high radar albedos of Psyche suggest that this differentiated asteroid is dominantly composed of metal. Psyche was previously found to be featureless in the 3-µm spectral region. However, in our study we found that this asteroid exhibits a 3-µm absorption feature, possibly indicating the presence of hydrated silicates.We have observed Psyche in the 3-µm spectral region, using the long-wavelength cross-dispersed (LXD:1.9-4.2 µm) mode of the SpeX spectrograph/imager at the NASA Infrared Telescope Facility (IRTF). For data reduction, we used the IDL (Interactive Data Language)-based spectral reduction tool Spextool (v4.1). Psyche was observed over the course of three nights with an apparent visual magnitude of ~9.50: 8 December 2015 (3 sets), 9 December 2015 (1 set), and 10 March 2016 (1 set). These observations have revealed that Psyche may exhibit a 3-µm absorption feature, similar to the sharp group in the 2.9-3.3-µm spectral range. Psyche also exhibits an absorption feature similar to the one in Ceres and Ceres-like group in the spectral 3.3-4.0-µm range. These 3-µm observational results revealed that Psyche may not be as featureless as once thought in the 3-µm spectral region.Evidence for the 3-µm band was found on the surfaces of many M-type asteroids and a number of plausible alternative interpretations for the presence of this 3-µm band were previously suggested. These interpretations include the presence of anhydrous silicates containing structural OH, the presence of fluid inclusions, the presence of xenolithic hydrous meteorite components on asteroid surfaces from impacts, solar wind-implanted H, or the presence of troilite. The detection of the Ceres-like feature in the 3.3-4.0-µm spectral range, however, would rule out some of these alternative interpretations, especially the solar wind-implanted H.

  12. The partial fission of fast spinning asteroids

    Science.gov (United States)

    Tardivel, Simon; Sanchez, Paul; Scheeres, Daniel J.

    2016-10-01

    The spin rates of asteroids systematically change over time due the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect. Above a certain spin rate that depends on the body's density, regions of an asteroid can enter in tension, with components held to the body by cohesive forces. When the body fails, deformation or fission can occur. Catastrophic fission leading to complete disruption has been directly observed in active asteroid P/2013 R3. Partial fission, the loss of only part of the body, has been proposed as a mechanism for the formation of binaries and is explored here.The equatorial cavities of (341843) 2008 EV5 and of (185851) 2000 DP107 (a binary system) are consistent with a localized partial fission of the body (LPSC 2016 #1036). The examination of the gravity field of these bodies reveals that a mass placed within these cavities could be shed. In this mechanism, the outward pull of inertial forces creates an average stress at the cavity interface of ≈1 Pa for 2008 EV5 and ≈3 Pa for 2000 DP107 at spin periods of ≈3.15 h for the assumed densities of 1.3 g/cm3.This work continues the study of this partial, localized fission. Specifically, it addresses the issue of the low cohesion necessary to the mechanism. These cohesion values are typically lower than global strength values inferred on other asteroids (10 - 200 Pa), meaning that partial fission may occur prior to larger-scale deformations. Yet, several processes can explain the discrepancy, as they can naturally segregate particles by size. For instance, landslides or granular convection (Brazil nut effect) could bring larger boulders to the equator of the body, while finer particles are left at higher latitudes or sink to the center. Conversely, failure of the interior could bring boulders to the surface. The peculiar profile shape of these asteroids, shared by many binaries (e.g. 1999 KW4, 1996 FG3) may also be a clue of this heterogeneity, as this "spin top" shape is obtained in simulations with

  13. Massive identification of asteroids in three-body resonances

    Science.gov (United States)

    Smirnov, Evgeny A.; Shevchenko, Ivan I.

    2013-01-01

    An essential role in the asteroidal dynamics is played by the mean motion resonances. Two-body planet-asteroid resonances are widely known, due to the Kirkwood gaps. Besides, so-called three-body mean motion resonances exist, in which an asteroid and two planets participate. Identification of asteroids in three-body (namely, Jupiter-Saturn-asteroid) resonances was initially accomplished by Nesvorný and Morbidelli (Nesvorný D., Morbidelli, A. [1998]. Astron. J. 116, 3029-3037), who, by means of visual analysis of the time behaviour of resonant arguments, found 255 asteroids to reside in such resonances. We develop specialized algorithms and software for massive automatic identification of asteroids in the three-body, as well as two-body, resonances of arbitrary order, by means of automatic analysis of the time behaviour of resonant arguments. In the computation of orbits, all essential perturbations are taken into account. We integrate the asteroidal orbits on the time interval of 100,000 yr and identify main-belt asteroids in the three-body Jupiter-Saturn-asteroid resonances up to the 6th order inclusive, and in the two-body Jupiter-asteroid resonances up to the 9th order inclusive, in the set of ˜250,000 objects from the "Asteroids - Dynamic Site" (AstDyS) database. The percentages of resonant objects, including extrapolations for higher-order resonances, are determined. In particular, the observed fraction of pure-resonant asteroids (those exhibiting resonant libration on the whole interval of integration) in the three-body resonances up to the 6th order inclusive is ≈0.9% of the whole set; and, using a higher-order extrapolation, the actual total fraction of pure-resonant asteroids in the three-body resonances of all orders is estimated as ≈1.1% of the whole set.

  14. OSIRIS-REx, Returning the Asteroid Sample

    Science.gov (United States)

    Ajluni, Thomas, M.; Everett, David F.; Linn, Timothy; Mink, Ronald; Willcockson, William; Wood, Joshua

    2015-01-01

    This paper addresses the technical aspects of the sample return system for the upcoming Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) asteroid sample return mission. The overall mission design and current implementation are presented as an overview to establish a context for the technical description of the reentry and landing segment of the mission.The prime objective of the OSIRIS-REx mission is to sample a primitive, carbonaceous asteroid and to return that sample to Earth in pristine condition for detailed laboratory analysis. Targeting the near-Earth asteroid Bennu, the mission launches in September 2016 with an Earth reentry date of September 24, 2023.OSIRIS-REx will thoroughly characterize asteroid Bennu providing knowledge of the nature of near-Earth asteroids that is fundamental to understanding planet formation and the origin of life. The return to Earth of pristine samples with known geologic context will enable precise analyses that cannot be duplicated by spacecraft-based instruments, revolutionizing our understanding of the early Solar System. Bennu is both the most accessible carbonaceous asteroid and one of the most potentially Earth-hazardous asteroids known. Study of Bennu addresses multiple NASA objectives to understand the origin of the Solar System and the origin of life and will provide a greater understanding of both the hazards and resources in near-Earth space, serving as a precursor to future human missions to asteroids.This paper focuses on the technical aspects of the Sample Return Capsule (SRC) design and concept of operations, including trajectory design and reentry retrieval. Highlights of the mission are included below.The OSIRIS-REx spacecraft provides the essential functions for an asteroid characterization and sample return mission: attitude control propulsion power thermal control telecommunications command and data handling structural support to ensure successful

  15. PRIMitive Asteroids Spectroscopic Survey - PRIMASS: First Results

    Science.gov (United States)

    de Leon, Julia; Pinilla-Alonso, Noemi; Campins, Humberto; Lorenzi, Vania; Licandro, Javier; Morate, David; Tanga, Paolo; Cellino, Alberto; Delbo, Marco

    2015-11-01

    NASA OSIRIS-REx and JAXA Hayabusa 2 sample-return missions have targeted two near-Earth asteroids: (101955) Bennu and (162173) 1999 JU3, respectively. These are primitive asteroids that are believed to originate in the inner belt, where five distinct sources have been identified: four primitive collisional families (Polana, Erigone, Sulamitis, and Clarissa), and a population of low-albedo and low-inclination background asteroids. Identifying and characterizing the populations from which these two NEAs might originate will enchance the science return of the two missions.With this main objective in mind, we initiated in 2010 a spectroscopic survey in the visible and the near-infrared to characterize the primitive collisional families in the inner belt and the low-albedo background population. This is the PRIMitive Asteroids Spectroscopic Survey - PRIMASS. So far we have obtained more than 200 spectra using telescopes located at different observatories. PRIMASS uses a variety of ground based facilities. Most of the spectra have been obtained using the 10.4m Gran Telescopio Canarias (GTC), and the 3.6m Telescopio Nazionale Galileo (TNG), both located at the El Roque de los Muchachos Observatory (La Palma, Spain), and the 3.0m NASA Infrared Telescope Facility on Mauna Kea (Hawai, USA).We present the first results from our on-going survey (de Leon et al. 2015; Pinilla-Alonso et al. 2015; Morate et al. 2015), focused on the Polana and the Erigone primitive families, with visible and near-infrared spectra of more than 200 objects, most of them with no previous spectroscopic data. Our survey is already the largest database of primitive asteroids spectra, and we keep obtaining data on the Sulamitis and the Clarissa families, as well as on the background low-albedo population.

  16. Near Earth Asteroid Characterization for Threat Assessment

    Science.gov (United States)

    Dotson, Jessie; Mathias, Donovan; Wheeler, Lorien; Wooden, Diane; Bryson, Kathryn; Ostrowski, Daniel

    2017-01-01

    Physical characteristics of NEAs are an essential input to modeling behavior during atmospheric entry and to assess the risk of impact but determining these properties requires a non-trivial investment of time and resources. The characteristics relevant to these models include size, density, strength and ablation coefficient. Some of these characteristics cannot be directly measured, but rather must be inferred from related measurements of asteroids and/or meteorites. Furthermore, for the majority of NEAs, only the basic measurements exist so often properties must be inferred from statistics of the population of more completely characterized objects. The Asteroid Threat Assessment Project at NASA Ames Research Center has developed a probabilistic asteroid impact risk (PAIR) model in order to assess the risk of asteroid impact. Our PAIR model and its use to develop probability distributions of impact risk are discussed in other contributions to PDC 2017 (e.g., Mathias et al.). Here we utilize PAIR to investigate which NEA characteristics are important for assessing the impact threat by investigating how changes in these characteristics alter the damage predicted by PAIR. We will also provide an assessment of the current state of knowledge of the NEA characteristics of importance for asteroid threat assessment. The relative importance of different properties as identified using PAIR will be combined with our assessment of the current state of knowledge to identify potential high impact investigations. In addition, we will discuss an ongoing effort to collate the existing measurements of NEA properties of interest to the planetary defense community into a readily accessible database.

  17. Geologic History of Asteroid 4 Vesta

    Science.gov (United States)

    Mittlefehldt, David W.

    2014-01-01

    Some types of meteorites - most irons, stony irons, some achondrites - hail from asteroids that were heated to the point where magmatism occurred within a very few million years of the formation of the earliest solids in the solar system. The largest clan of achondrites, the howardite, eucrite and diogenite (HED) meteorites, represent the crust of their parent asteroid]. Diogenites are cumulate harzburgites and orthopyroxenites from the lower crust whilst eucrites are basalts, diabases and cumulate gabbros from the upper crust. Howardites are impact-engendered breccias mostly of diogenites and eucrites. There remains only one large asteroid with a basaltic crust, 4 Vesta, which is thought to be the source of the HED clan. Differentiation models for Vesta are based on HED compositions. Proto-Vesta consisted of chondritic materials containing Al-26, a potent, short-lived heat source. Inferences from compositional data are that Vesta was melted to high degree (=50%) allowing homogenization of the silicate phase and separation of a metallic core. Convection of the silicate magma ocean allowed equilibrium crystallization, forming a harzburgitic mantle. After convective lockup occurred, melt collected between the mantle and the cool thermal boundary layer and underwent fractional crystallization forming an orthopyroxene-rich (diogenite) lower crust. The initial thermal boundary layer of chondritic material was replaced by a mafic upper crust through impact disruption and foundering. The mafic crust thickened over time as additional residual magma intrudes and penetrates the mafic crust forming plutons, dikes, sills and flows of cumulate and basaltic eucrite composition. This magmatic history may have taken only 2-3 Myr. This magma ocean scenario is at odds with a model of heat and magma transport that indicates that small degrees of melt would be rapidly expelled from source regions, precluding development of a magma ocean. Constraints from radiogenic Mg-26 distibutions

  18. Multi-system influences on adolescent risky sexual behavior.

    Science.gov (United States)

    Chen, Angela Chia-Chen; Thompson, Elaine Adams; Morrison-Beedy, Dianne

    2010-12-01

    We examined multi-system influences on risky sexual behavior measured by cumulative sexual risk index and number of nonromantic sexual partners among 4,465 single, sexually experienced adolescents. Hierarchical Poisson regression analyses were conducted with Wave I-II data from the National Longitudinal Study of Adolescent Health. Individual and family factors predicted both outcome measures. Neighborhood set predicted cumulative sexual risk index only, and peer factors predicted the number of nonromantic sexual partners only. School set did not predict either outcome. There were significant associations among risky sexual behavior, drug use, and delinquent behaviors. The results highlight the need for multifaceted prevention programs that address relevant factors related to family, peer and neighborhood influence as well as individual factors among sexually active adolescents. Copyright © 2010 Wiley Periodicals, Inc.

  19. Enhanced Gravity Tractor Derived from the Asteroid Redirect Mission for Deflecting Hypothetical Asteroid 2017 PDC

    Science.gov (United States)

    Mazanek, Daniel D.; Reeves, David M.; Abell, Paul A.; Shen, Haijun; Qu, Min

    2017-01-01

    The Asteroid Redirect Mission (ARM) concept would robotically visit a hazardous-size near-Earth asteroid (NEA) with a rendezvous spacecraft, collect a multi-ton boulder and regolith samples from its surface, demonstrate an innovative planetary defense technique known as the Enhanced Gravity Tractor (EGT), and return the asteroidal material to a stable orbit around the Moon, allowing astronauts to explore the returned material in the mid-2020s. Launch of the robotic vehicle to rendezvous with the ARM reference target, NEA (341843) 2008 EV5, would occur in late 2021 [1,2]. The robotic segment of the ARM concept uses a 40 kW Solar Electric Propulsion (SEP) system with a specific impulse (Isp) of 2600 s, and would provide the first ever demonstration of the EGT technique on a hazardous-size asteroid and validate one method of collecting mass in-situ. The power, propellant, and thrust capability of the ARM robotic spacecraft can be scaled from a 40 kW system to 150 kW and 300 kW, which represent a likely future power level progression. The gravity tractor technique uses the gravitational attraction of a station-keeping spacecraft with the asteroid to provide a velocity change and gradually alter the trajectory of the asteroid. EGT utilizes a spacecraft with a high-efficiency propulsion system, such as Solar Electric Propulsion (SEP), along with mass collected in-situ to augment the mass of the spacecraft, thereby increasing the gravitational force between the objects [3]. As long as the spacecraft has sufficient thrust and propellant capability, the EGT force is only limited by the amount of in-situ mass collected and can be increased several orders of magnitude compared to the traditional gravity tractor technique in which only the spacecraft mass is used to generate the gravitational attraction force. This increase in available force greatly reduces the required deflection time. The collected material can be a single boulder, multiple boulders, regolith, or a

  20. Preventing Risky Drinking in Veterans Treated with Prescription Opioids

    Science.gov (United States)

    2017-04-01

    RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE April 2017 2. REPORT TYPE ANNUAL 3. DATES COVERED 1April2016 - 31March2017 4. TITLE AND...engaging in risky drinking are at heightened risk for drug interactions, including overdose and other negative effects, particularly if they are also...messages. We propose to conduct a study in which returning OEF/OIF individuals and other veterans receiving medical care at the Philadelphia VAMC (N

  1. Reducing Risky Alcohol Use: What Health Care Systems Can Do.

    Science.gov (United States)

    Quinn, Amity E; Brolin, Mary; Stewart, Maureen T; Evans, Brooke; Horgan, Constance

    2016-04-27

    Risky, non-dependent alcohol use is prevalent in the United States, affecting 25% of adults (Centers for Disease Control and Prevention, 2014b). Massachusetts has higher rates of alcohol use and binge drinking than most states (Substance Abuse and Mental Health Services Administration, 2015). Serious physical, social, and economic consequences result. Excessive alcohol use contributes to cancer, cardiovascular disease, sleep disorders, birth defects, motor vehicle injuries, and suicide, and it complicates management of chronic illnesses (Green, McKnight-Eily, Tan, Mejia, & Denny, 2016; Laramee et al., 2015; Mokdad, Marks, Stroup, & Gerberding, 2004; Rehm et al., 2009). Excessive alcohol use is one of the top causes of death, and over 240 alcohol-related deaths occur daily in the US (Mokdad et al., 2004; Stahre, Roeber, Kanny, Brewer, & Zhang, 2014). In comparison, 78 people die from an opioid overdose each day (Centers for Disease Control and Prevention, 2016). Excessive drinking is estimated to cost over $249 billion annually in the US and $5.6 billion in the Commonwealth (Sacks, Gonzales, Bouchery, Tomedi, & Brewer, 2015). This issue brief describes the scope of the risky drinking problem in the US and associated costs and consequences. The brief then examines the evidence base for tools to address risky drinking and outlines policy strategies that health care system stakeholders may employ to address further this critical public health issue. Screening and brief intervention (SBI) is an evidence-based, cost-effective practice to address risky alcohol use, typically using a short validated screening tool followed by a brief counseling session if a patient screens positive. Research shows SBI conducted in primary care outpatient settings significantly reduces alcohol use (Bertholet, Daeppen, Wietlisbach, Fleming, & Burnand, 2005b; Bien, Miller, & Tonigan, 1993; Kaner et al., 2009; Saitz, 2010a), hospitalizations (Fleming, Barry, Manwell, Johnson, & London, 1997b

  2. IMPACT OF ASPIRATIONS ON RISK JUDGMENT AND ON RISKY CHOICES

    Directory of Open Access Journals (Sweden)

    Joanna Sokołowska

    2012-06-01

    Full Text Available The presented experiments are aimed at determining: (1 whether risk perception and risk acceptance are two distinct psychological processes and (2 how aspirations affect each process. It has been tested whether risk is independent of and preferences are depend on aspirations. In Experiment 172 employees of a high-tech company were presented with pairs of risky projects. The aspiration level was de fined as the target return on the project and was set through an explicit instruction. In Experiment 2 93 bridge players were presented with pairs of contracts – one a sure thing and the other a risky one. The aspiration level was related to the team IMP points after the first part of a knockout tournament and was set through an instruction. In both experiments with a between-subject design, two different aspiration levels were set for each group. All respondents were asked to judge riskiness of presented options and to select one. The results indicate that risk perception is insensitive to changes in aspirations, but preferences are. This supports distinctness of risk perception and risk cceptance.

  3. A Mixture IRT Analysis of Risky Youth Behavior

    Directory of Open Access Journals (Sweden)

    Holmes eFinch

    2011-05-01

    Full Text Available The study reported in this manuscript used a mixture item response model with data from the Youth Risk Behavior Survey 2009 (N = 16,410 to identify subtypes of adolescents at-risk for engaging in unhealthy behaviors, and to find individual survey items that were most effective at identifying such students within each subtype. The goal of the manuscript is twofold: 1 To demonstrate the utility of the mixture item response theory model for identifying subgroups in the population and for highlighting the use of group specific item response parameters and 2 To identify typologies of adolescents based on their propensity for engaging in sexually and substance use risky behaviors. Results indicate that 4 classes of youth exist in the population, with differences in risky sexual behaviors and substance use. The first group had a greater propensity to engage in risky sexual behavior, while group 2 was more likely to smoke tobacco and drink alcohol. Group 3 was the most likely to use other substances, such as marijuana, methamphetamine, and other mind altering drugs, and group 4 had the lowest propensity for engaging in any of the sexual or substance use behaviors included in the survey. Finally, individual items were identified for each group that can be most effective at identifying individuals at greatest risk. Further proposed directions of research and the contribution of this analysis to the existing literature are discussed.

  4. Managing risks in business model innovation processes

    DEFF Research Database (Denmark)

    Taran, Yariv; Boer, Harry; Lindgren, Peter

    2010-01-01

    ) innovation is a risky enterprise, many companies are still choosing not to apply any risk management in the BM innovation process. The objective of this paper is to develop a better understanding of how risks are handled in the practice of BM innovation. An analysis of the BM innovation experiences of two......Companies today, in some industries more than others, invest more capital and resources just to stay competitive, develop more diverse solutions, and increasingly start thinking more radically when considering their business models. However, despite the understanding that business model (BM...... industrial companies shows that both companies are experiencing high levels of uncertainty and complexity during their innovation processes and are, consequently, struggling to find new processes for handling the risks involved. Based on the two companies’ experiences, various testable propositions are put...

  5. Regolith Levitation on Small Fast Rotating Asteroids

    Science.gov (United States)

    Campo Bagatin, Adriano; Moreno, Fernando; Molina, Antonio

    2014-11-01

    A number of NEAs larger than few hundred meters are found with relatively high spin rates (from ~2.2 to less than 4 hr, depending on composition). On those bodies, local acceleration near their equator may be directed outwards, as in the case of the primaries of binary asteroids Didymos and 1996 FG3. They both are potential targets of future space missions. What are the effects of high spin states on regolith material at low asteroidal latitudes?NEAs come from the asteroid belt and are believed to be mostly gravitational aggregates at D > 0.5 - 1 km due to their former collisional evolution history (Campo Bagatin et al, 2001). Once in the inner Solar System, NEAs may undergo spin up evolution through YORP causing their components to disperse, shed mass or fission and eventually form binary, multiple systems or asteroid pairs (Walsh et al, 2008, Jacobson and Scheers, 2010, Pravec et al, 2009 and 2010). The end state of those events is often an object spinning above any Chandrasekhar stability limit, kept together by friction (Holsapple, 2007) and sometimes characterized by an equatorial “bulge”, as shown by radar images (Ostro et al, 2006).The centrifugal force acting on surface particles at equatorial latitudes may overcome the gravitational pull of the asteroid itself, and particles may leave its suface. Centrifugal is an apparent contact force, and as soon as particles lift off they mainly move under the gravitational field of the asteroid and the satellite, they may levitate for some time, land on the surface and repeat this cycle over and over. We are studying the motion of particles in the 1 μm to 10 cm range in the non-inertial reference frame of the rotating primary, accounting for centrifugal and Coriolis apparent forces as well as the gravitational fields of the primary, the secondary, the Sun and the radiation forces by the Sun itself. The main features of this effect are presented in the case of Didymos and 1996 FG3.

  6. Risky business: trauma exposure and rate of posttraumatic stress disorder in African American children and adolescents.

    Science.gov (United States)

    Hunt, Kristin L; Martens, Patricia M; Belcher, Harolyn M E

    2011-06-01

    Demographics, parental risk factors, and experiencing interpersonal trauma (domestic violence, community violence, and physical and sexual abuse) are related to childhood posttraumatic stress disorder (PTSD). Little is known about these factors and the risk of PTSD in African American children. This study examined associations between PTSD symptoms and gender, age, parent mental illness, parent substance abuse, and interpersonal trauma in African American children. Participants were 257 children and adolescents, ages 8-17 years (M = 11.7, SD = 2.5), who received outpatient mental health treatment. Being female and witnessing domestic violence was associated with more PTSD symptoms. Exposure to community violence and physical abuse increased the odds of clinically significant PTSD symptomatology by more than 2 times. The rate of PTSD (16%) was lower in the current study than in other same-age study populations (25%-40%). Risk factors and identification strategies for PTSD are discussed.

  7. Risky Business: Why DoD Needs a New Risk Management Paradigm

    Science.gov (United States)

    2013-08-01

    DoDI) 5000.2—“Operation of the Defense Acquisi-tion System”—the DoD’s “ Bible ” for Program Management (PM), uses the word “risk” 67 times within its 80...RM.” The answer to the first ques- tion is the basis for this article. The lack of guidance on RM in the DoD acquisition “ Bible ” is indicative of a

  8. Risky Business: Fundamentals for a Security Consensus in 1990’s and Beyond

    Science.gov (United States)

    1992-06-01

    INDIVIDUAL 22b. TELEPHONE (Include Area Code) 22c. OFFICE SYMBOL OBERT C. WHITE, JR., COL, MI 717/245-3044 AWCA DO Form 1473, JUN 86 Previous editions...8217Faustian Bargain’?" Toward Minimum Deterrence: How Low Can We Go?, ed. Peter Gizewski. Ottawa: Canadian Centre for Arms Control and Disarmament, 1991

  9. Risky business: factor analysis of survey data - assessing the probability of incorrect dimensionalisation.

    Directory of Open Access Journals (Sweden)

    Cees van der Eijk

    Full Text Available This paper undertakes a systematic assessment of the extent to which factor analysis the correct number of latent dimensions (factors when applied to ordered-categorical survey items (so-called Likert items. We simulate 2400 data sets of uni-dimensional Likert items that vary systematically over a range of conditions such as the underlying population distribution, the number of items, the level of random error, and characteristics of items and item-sets. Each of these datasets is factor analysed in a variety of ways that are frequently used in the extant literature, or that are recommended in current methodological texts. These include exploratory factor retention heuristics such as Kaiser's criterion, Parallel Analysis and a non-graphical scree test, and (for exploratory and confirmatory analyses evaluations of model fit. These analyses are conducted on the basis of Pearson and polychoric correlations. We find that, irrespective of the particular mode of analysis, factor analysis applied to ordered-categorical survey data very often leads to over-dimensionalisation. The magnitude of this risk depends on the specific way in which factor analysis is conducted, the number of items, the properties of the set of items, and the underlying population distribution. The paper concludes with a discussion of the consequences of over-dimensionalisation, and a brief mention of alternative modes of analysis that are much less prone to such problems.

  10. Risky business: factor analysis of survey data - assessing the probability of incorrect dimensionalisation.

    Science.gov (United States)

    van der Eijk, Cees; Rose, Jonathan

    2015-01-01

    This paper undertakes a systematic assessment of the extent to which factor analysis the correct number of latent dimensions (factors) when applied to ordered-categorical survey items (so-called Likert items). We simulate 2400 data sets of uni-dimensional Likert items that vary systematically over a range of conditions such as the underlying population distribution, the number of items, the level of random error, and characteristics of items and item-sets. Each of these datasets is factor analysed in a variety of ways that are frequently used in the extant literature, or that are recommended in current methodological texts. These include exploratory factor retention heuristics such as Kaiser's criterion, Parallel Analysis and a non-graphical scree test, and (for exploratory and confirmatory analyses) evaluations of model fit. These analyses are conducted on the basis of Pearson and polychoric correlations. We find that, irrespective of the particular mode of analysis, factor analysis applied to ordered-categorical survey data very often leads to over-dimensionalisation. The magnitude of this risk depends on the specific way in which factor analysis is conducted, the number of items, the properties of the set of items, and the underlying population distribution. The paper concludes with a discussion of the consequences of over-dimensionalisation, and a brief mention of alternative modes of analysis that are much less prone to such problems.

  11. Risky Business: The Global Threat Network and the Politics of Contraband

    Science.gov (United States)

    2014-05-01

    the coup and civil war in Mali.19 Other well-documented examples include the Revolutionary Armed Forces of Colombia (FARC) and the Abu Sayyaf group in...throes of civil wars in failed states, others involved in subversive campaigns against capable governments along with a fair share of sovereign...of Poverty and Inequality: A Review Focusing on Developing Countries,” Revista Desarrollo y Sociedad (September 1999), 61–99. 74 Ibid. 75 E. Britt

  12. The risky business of dopamine agonists in Parkinson disease and impulse control disorders

    NARCIS (Netherlands)

    Claassen, D.O.; van den Wildenberg, W.P.M.; Ridderinkhof, K.R.; Jessup, C.K.; Harrison, M.B.; Wooten, G.F.; Wylie, S.A.

    2011-01-01

    Risk-taking behavior is characterized by pursuit of reward in spite of potential negative consequences. Dopamine neurotransmission along the mesocorticolimbic pathway is a potential modulator of risk behavior. In patients with Parkinson's disease (PD), impulse control disorder (ICD) can result from

  13. Is cell culture a risky business? Risk analysis based on scientist survey data.

    Science.gov (United States)

    Shannon, Mark; Capes-Davis, Amanda; Eggington, Elaine; Georghiou, Ronnie; Huschtscha, Lily I; Moy, Elsa; Power, Melinda; Reddel, Roger R; Arthur, Jonathan W

    2016-02-01

    Cell culture is a technique that requires vigilance from the researcher. Common cell culture problems, including contamination with microorganisms or cells from other cultures, can place the reliability and reproducibility of cell culture work at risk. Here we use survey data, contributed by research scientists based in Australia and New Zealand, to assess common cell culture risks and how these risks are managed in practice. Respondents show that sharing of cell lines between laboratories continues to be widespread. Arrangements for mycoplasma and authentication testing are increasingly in place, although scientists are often uncertain how to perform authentication testing. Additional risks are identified for preparation of frozen stocks, storage and shipping.

  14. Risky business or not? FIFOs, sexual risk taking and the Australian mining industry.

    Science.gov (United States)

    O'Mullan, Cathy; Debattista, Joseph; Browne, Matthew

    2016-04-01

    Issue addressed The fly-in, fly-out (FIFO) and drive-in, drive-out (DIDO) models of mining in Australia have led to concerns about adverse health and psychosocial impacts. Despite speculation that increased levels of sexually transmitted infections (STIs) in Australia, including HIV, are associated with FIFO/DIDO work, we know little about sexual risk-taking behaviours in mining populations. This study explores differences in sexual risk taking and perceptions of risk between FIFO/DIDO miners and residential miners. Methods A cross-sectional survey was administered to a sample (n=444) of male miners working in Queensland, Australia. The self-completed survey contained 49 questions relating to knowledge, attitudes and behaviour and included demographic information and specific items related to sex and relationships. Results FIFO/DIDO status was not associated with any differential sexual risk-taking behaviours, except for an increased probability of reporting 'ever being diagnosed with an STI'; 10.8% of FIFO/DIDO respondents versus 3.6% of others (x(2) (1)=4.43, P=0.35). Conclusions Our results appear to counter anecdotal evidence that FIFO/DIDO miners engage in higher sexual risk behaviours when compared with residential miners. So what? Anecdotal evidence linking the rise of sexually transmitted infections with the FIFO/DIDO mining workforce could drive costly and unnecessary approaches to prevention. Further research, surveillance and monitoring are required to inform health promotion interventions.

  15. Risky business: Lived experience mental health practice, nurses as potential allies.

    Science.gov (United States)

    Byrne, Louise; Happell, Brenda; Reid-Searl, Kerry

    2017-06-01

    Mental health policy includes a clear expectation that consumers will participate in all aspects of the design and delivery of mental health services. This edict has led to employment roles for people with lived experience of significant mental health challenges and service use. Despite the proliferation of these roles, research into factors impacting their success or otherwise is limited. This paper presents findings from a grounded theory study investigating the experiences of Lived Experience Practitioners in the context of their employment. In-depth interviews were conducted with 13 Lived Experience Practitioners. Risk was identified as a core category, and included sub-categories: vulnerability, 'out and proud', fear to disclose, and self-care. Essentially participants described the unique vulnerabilities of their mental health challenges being known, and while there were many positives about disclosing there was also apprehension about personal information being so publically known. Self-care techniques were important mediators against these identified risks. The success of lived experience roles requires support and nurses can play an important role, given the size of the nursing workforce in mental health, the close relationships nurses enjoy with consumers and the contribution they have made to the development of lived experience roles within academia. © 2016 Australian College of Mental Health Nurses Inc.

  16. Risky Business: Sustainability and Industrial Land Use across Seattle’s Gentrifying Riskscape

    Directory of Open Access Journals (Sweden)

    Troy D. Abel

    2015-11-01

    Full Text Available This paper examines the spatial and temporal trajectories of Seattle’s industrial land use restructuring and the shifting riskscape in Seattle, WA, a commonly recognized urban model of sustainability. Drawing on the perspective of sustainability as a conflicted process, this research explored the intersections of urban industrial and nonindustrial land use planning, gentrification, and environmental injustice. In the first part of our research, we combine geographic cluster analysis and longitudinal air toxic emission comparisons to quantitatively investigate socioeconomic changes in Seattle Census block-groups between 1990, 2000, and 2009 coupled with measures of pollution volume and its relative potential risk. Second, we qualitatively examine Seattle’s historical land use policies and planning and the growing tension between industrial and nonindustrial land use. The gentrification, green cities, and growth management conflicts embedded within sustainability/livability lead to pollution exposure risk and socioeconomic vulnerability converging in the same areas and reveal one of Seattle’s significant environmental challenges. Our mixed-method approach can guide future urban sustainability studies to more effectively examine the connections between land use planning, industrial displacement, and environmental injustice. Our results also help sustainable development practitioners recognize that a more just sustainability in Seattle and beyond will require more planning and policy attention to mitigate obscured industrial land use conflicts.

  17. Risky Business: Risk Management, Loss Prevention and Insurance Procurement for Colleges and Universities. NACUA Publication Series.

    Science.gov (United States)

    Bennett, Barbara

    No matter what type of insurance or how much actual coverage an individual college or university obtains, it will always pay for its own losses one way or another. This pamphlet is intended to assist colleges and universities to meet that challenge by providing administrators with a structure for analyzing and managing risks and determining the…

  18. Risky Business : Political Instability and Greenfield Foreign Direct Investment in the Arab World

    NARCIS (Netherlands)

    M.J. Burger (Martijn); E.I. Ianchovichina (Elena); B. Rijkers (Bob)

    2013-01-01

    textabstractWhich foreign direct investments are most affected by political instability? Analysis of quarterly greenfield investment flows into countries in the Middle East and North Africa from 2003 to 2012 shows that adverse political shocks are associated with significantly reduced investment inf

  19. The Case of Freedom of Expression in Egypt: The Risky Business of Expressing an Opinion

    DEFF Research Database (Denmark)

    Elsayed, Ahmed Mohamed Abdelfattah

    2013-01-01

    committing it. Furthermore, in an unprecedented move against non-Arabic press, it had been reported that the government pressure led to the shutdown of ‘Egypt Independent’ a private newspaper published in English. Despite that laws related to freedom of expression and media had hardly changed from Mubarak...... to Morsi, this paper aims to track down the behavioral changes in implementing these laws under both Presidents....

  20. Problematizing "Risk" and the Principalship: The Risky Business of Managing Risk in Schools

    Science.gov (United States)

    Starr, Karen

    2012-01-01

    Over the past two decades, risk in education has stimulated increasing attention and prominence, with principals bearing responsibility and liability for "managing" risk in schools. As a consequence, compulsory risk compliance regimes have become increasingly complex, technical and time-consuming. This article focuses on the responses of…

  1. Facebook and Issues of Professionalism in Undergraduate Nursing Education: Risky Business or Risk Worth Taking?

    Science.gov (United States)

    Killam, Laura Anne; Carter, Lorraine; Graham, Rob

    2013-01-01

    The purpose of this exploratory investigation was to share the strengths, challenges, and tensions of using Facebook in an undergraduate nursing program. The observations presented have emerged from information shared by study participants and the professional insights of the three researcher-authors who represent perspectives from nursing,…

  2. The Case of Freedom of Expression in Egypt: The Risky Business of Expressing an Opinion

    DEFF Research Database (Denmark)

    Elsayed, Ahmed Mohamed Abdelfattah

    2013-01-01

    committing it. Furthermore, in an unprecedented move against non-Arabic press, it had been reported that the government pressure led to the shutdown of ‘Egypt Independent’ a private newspaper published in English. Despite that laws related to freedom of expression and media had hardly changed from Mubarak...

  3. Ethics of birth at the limits of viability: the risky business of prediction.

    Science.gov (United States)

    Shinwell, Eric S

    2015-01-01

    Infants born at the limits of viability present neonatologists in particular and society in general with difficult challenges. Ethical and legal considerations establish a framework for action, although this varies between countries, departments and individuals and shows dynamic changes over time. This brief review includes a vignette telling a familiar story. In this case, the parents ask searching questions and the caring, knowledgeable neonatologist uses up-to-date information to offer empathic and thoughtful guidance - a challenge for all.

  4. Risky Business: Risk Tolerance in U.S. Army Special Forces

    Science.gov (United States)

    2014-06-01

    extrinsic rewards like a monetary bonus, but include intrinsic ... intrinsic and extrinsic rewards . In military units, intrinsic rewards are considered more important than extrinsic rewards . Intrinsic rewards can include...peer recognition, additional tasks, increased responsibility, increased autonomy, and trust. Extrinsic rewards can include good

  5. Risky Business: Applying Ethical Standards to Social Media Use with Vulnerable Populations

    Directory of Open Access Journals (Sweden)

    Hillary Rose Dolinsky

    2015-07-01

    Full Text Available Social media is changing how those in the helping professions offer clinical, medical, or educational services, provide referrals, administer therapeutic interventions, and conduct research. Non-profits and government organizations working with vulnerable populations need to consider the possibility of ethical mistakes when using social media. A comparison of Facebook strategies used with the National Youth in Transition Database (NYTD mandate to engage and locate current and former youth in the child welfare system was conducted. Facebook practices and strategies were examined based on the National Association of Social Workers (NASW Code of Ethics and the Association of Social Work Boards (ASWB Standards for Technology and Social Work Practice. The ethical standards examined include: obtaining consent, preserving confidentiality, verifying youth identity online, and avoiding disclosure of foster care affiliation. Findings demonstrate the importance of providing guidelines and best practices when adopting social media tools for interacting with vulnerable populations.

  6. Conscious and unconscious thought in risky choice: Testing the capacity principle and the appropriate weighting principle of Unconscious Thought Theory

    Directory of Open Access Journals (Sweden)

    Nathaniel James Siebert Ashby

    2011-10-01

    Full Text Available Daily we make decisions ranging from the mundane to the seemingly pivotal that shape our lives. Assuming rationality, all relevant information about one’s options should be thoroughly examined in order to make the best choice. However, some findings suggest that under specific circumstances thinking too much has disadvantageous effects on decision quality and that it might be best to let the unconscious do the busy work. In three studies we test the capacity assumption and the appropriate weighting principle of unconscious thought theory using a classic risky choice paradigm and including a ‘deliberation with information’ condition. Although we replicate an advantage for unconscious thought over ‘deliberation without information’, we find that ‘deliberation with information’ equals or outperforms unconscious thought in risky choices. These results speak against the generality of the assumption that unconscious thought has a higher capacity for information integration and show that this capacity assumption does not hold in all domains. We furthermore show that ‘deliberate thought with information’ leads to more differentiated knowledge compared to unconscious thought which speaks against the generality of the appropriate weighting assumption.

  7. Reverse Asteroids: Searching for an Effective Tool to Combat Asteroid Belt Misconceptions

    Science.gov (United States)

    Summers, F.; Eisenhamer, B.

    2014-12-01

    The public 'knows' that asteroid belts are densely packed and dangerous for spaceships to cross. Visuals from "Star Wars" to, unfortunately, the recent "Cosmos" TV series have firmly established this astronomical misconception. However, even scientifically correct graphics, such as the Minor Planet Center's plot of the inner solar system, reinforces that view. Each pixel in the image is more than a million kilometers in width, making an accurate representation of the object density impossible.To address this widespread misconception, we are investigating an educational exercise built around a computer interactive that we call "Reverse Asteroids". In the arcade classic video game, the asteroids came to the player's spaceship. For our reverse implementation, we consider an inquiry-based activity in which the spaceship must go hunting for the asteroids, using a database of real objects in our solar system. Both 3D data visualization and basic statistical analysis play crucial roles in bringing out the true space density within the asteroid belt, and perhaps a reconciliation between imagination and reality. We also emphasize that a partnership of scientists and educators is fundamental to the success of such projects.

  8. Asteroids - the modern challenge of celestial dynamics

    Science.gov (United States)

    Dikova, Smiliana

    2002-11-01

    Among the most powerful statements in Science are those that mark absolute limits to knowledge. For example, Relativity and Quantum Theory touched the limits of speed and accuracy. Deterministic Chaos - the new scientific paradigma of our days, also falls in this class theories. Chaos means complexity in space and unpredictability in time. It shows the limit of our basic counting system and leads to a limited predictability of the long time dynamical evolution. Perhaps for that reason, in 1986 Sir James Lighthill remarked for all physicists: "We collectively wish to apologize for having misled the general educated public by spreading ideas about the determinism of systems satisfying Newton's laws of motion that, after 1960, were proved incorrect." Our main thesis is that Asteroid Dynamics is the arena where the drama Chaos versus predictability is initiated and developed. The aim of the present research is to show the way in which Deterministic Chaos restricts the long term dynamical predictability of asteroid motions.

  9. Computation of Asteroid Proper Elements: Recent Advances

    Science.gov (United States)

    Knežević, Z.

    2017-06-01

    The recent advances in computation of asteroid proper elements are briefly reviewed. Although not representing real breakthroughs in computation and stability assessment of proper elements, these advances can still be considered as important improvements offering solutions to some practical problems encountered in the past. The problem of getting unrealistic values of perihelion frequency for very low eccentricity orbits is solved by computing frequencies using the frequency-modified Fourier transform. The synthetic resonant proper elements adjusted to a given secular resonance helped to prove the existence of Astraea asteroid family. The preliminary assessment of stability with time of proper elements computed by means of the analytical theory provides a good indication of their poorer performance with respect to their synthetic counterparts, and advocates in favor of ceasing their regular maintenance; the final decision should, however, be taken on the basis of more comprehensive and reliable direct estimate of their individual and sample average deviations from constancy.

  10. The Bering small vehicle asteroid mission concept

    DEFF Research Database (Denmark)

    Michelsen, Rene; Andersen, Anja; Haack, Henning

    2004-01-01

    targets. The dilemma obviously being the resolution versus distance and the statistics versus DeltaV requirements. Using advanced instrumentation and onboard autonomy, we have developed a space mission concept whose goal is to map the flux, size, and taxonomy distributions of asteroids. The main focus......The study of asteroids is traditionally performed by means of large Earth based telescopes, by means of which orbital elements and spectral properties are acquired. Space borne research, has so far been limited to a few occasional flybys and a couple of dedicated flights to a single selected target....... Although the telescope based research offers precise orbital information, it is limited to the brighter, larger objects, and taxonomy as well as morphology resolution is limited. Conversely, dedicated missions offer detailed surface mapping in radar, visual, and prompt gamma, but only for a few selected...

  11. Is 1220 Crocus a precessing, binary asteroid?

    Science.gov (United States)

    Binzel, R. P.

    1985-01-01

    Photoelectric data of the asteroid 1220 Crocus over a 13 night period in 1984 revealed the presence of two separate periods. The light curves were indicative of a precessing body, but not one in free precession due to motions induced by a collision. Closer examinations revealed periods of 30.7 and 7.9 hr with amplitudes of 0.87 and 0.15 mag, respectively. An analysis of the source of an external torque which could be causing a forced precession led to the hypothesis that 1220 Crocus has a satellite. Verification of the binary asteroid configuration will depend on more detailed light curves, the possible modulation of the shorter period by the longer, and possible use of the Space Telescope.

  12. Is 1220 Crocus a precessing, binary asteroid?

    Science.gov (United States)

    Binzel, R. P.

    1985-07-01

    Photoelectric data of the asteroid 1220 Crocus over a 13 night period in 1984 revealed the presence of two separate periods. The light curves were indicative of a precessing body, but not one in free precession due to motions induced by a collision. Closer examinations revealed periods of 30.7 and 7.9 hr with amplitudes of 0.87 and 0.15 mag, respectively. An analysis of the source of an external torque which could be causing a forced precession led to the hypothesis that 1220 Crocus has a satellite. Verification of the binary asteroid configuration will depend on more detailed light curves, the possible modulation of the shorter period by the longer, and possible use of the Space Telescope.

  13. Asteroid absolute magnitudes and slope parameters

    Science.gov (United States)

    Tedesco, Edward F.

    1991-01-01

    A new listing of absolute magnitudes (H) and slope parameters (G) has been created and published in the Minor Planet Circulars; this same listing will appear in the 1992 Ephemerides of Minor Planets. Unlike previous listings, the values of the current list were derived from fits of data at the V band. All observations were reduced in the same fashion using, where appropriate, a single basis default value of 0.15 for the slope parameter. Distances and phase angles were computed for each observation. The data for 113 asteroids was of sufficiently high quality to permit derivation of their H and G. These improved absolute magnitudes and slope parameters will be used to deduce the most reliable bias-corrected asteroid size-frequency distribution yet made.

  14. New CCD photometry of asteroid (1028) Lydina

    Institute of Scientific and Technical Information of China (English)

    Yi-Bo Wang; Xiao-Bin Wang

    2012-01-01

    New CCD photometric observations for asteroid (1028) Lydina,carried out with the 1-m and 2.4-m telescopes at Yunnan Observatory from 2011 December 19 to 2012 February 3,are presented.Using the new light curves,the rotation period of 11.680±0.001 hours is derived with the Phase Dispersion Minimization (PDM) method.In addition,using the Amplitude-Aspect method,the elementary results of the pole orientation of asteroid (1028) Lydina are obtained:λp= 111°+4°-4°,βp= 31°+4°-5°.Meanwhile,the axial ratios of the tri-axial ellipsoid are estimated:a/b = 1.77+0.10-0.08and b/c = 1.17+0.07-0.09.

  15. Equilibrium figures of inhomogeneous synchronous binary asteroids

    Science.gov (United States)

    Descamps, P.

    2010-06-01

    The present paper deals with the application of the classical theory of equilibrium figures of two rotating liquid masses to the case where bodies exhibit a radially stratified internal density distribution so that they can be considered as inhomogeneous bodies. The derived ellipsoidal shape solutions are applied to five real systems of equal-sized synchronous asteroids. Furthermore, internal inhomogeneity puts strong constraints on the surface grain density. A satisfactory model fit is achieved with internal densities of asteroids steadily increasing outwards. In particular, from such an approach we derived grain densities of the considered systems in agreement with their mineralogical composition inferred from reflectance spectroscopy. According to this new approach, 4492 Debussy, presently of unknown spectral type, is predicted to appear as a C-type object with a grain density on the order of 2 g/cm 3.

  16. Effective stability of the Trojan asteroids

    CERN Document Server

    Skokos, C; Skokos, Ch.

    2001-01-01

    We study the spatial circular restricted problem of three bodies in the light of Nekhoroshev theory of stability over large time intervals. We consider in particular the Sun-Jupiter model and the Trojan asteroids in the neighborhood of the Lagrangian point $L_4$. We find a region of effective stability around the point $L_4$ such that if the initial point of an orbit is inside this region the orbit is confined in a slightly larger neighborhood of the equilibrium (in phase space) for a very long time interval. By combining analytical methods and numerical approximations we are able to prove that stability over the age of the universe is guaranteed on a realistic region, big enough to include one real asteroid. By comparing this result with the one obtained for the planar problem we see that the regions of stability in the two cases are of the same magnitude.

  17. Catalogue of ISO LWS observations of asteroids

    CERN Document Server

    Hormuth, Felix

    2009-01-01

    (Abridged) The Long Wavelength Spectrometer (LWS) onboard the Infrared Space Observatory (ISO) observed the four large main-belt asteroids (1) Ceres, (2) Pallas, (4) Vesta, and (10) Hygiea multiple times. The photometric and spectroscopic data cover the wavelength range between 43 and 197 um, and are a unique dataset for future investigations and detailed characterisations of these bodies. The standard ISO archive products, produced through the last post-mission LWS pipeline, were still affected by instrument artefacts. Our goal was to provide the best possible data products to exploit the full scientific potential of these observations. We performed a refined reduction of all measurements, corrected for various instrumental effects, and re-calibrated the data. We outline the data reduction process and give an overview of the available data and the quality of the observations. We apply a thermophysical model to the flux measurements to derive far-IR based diameter and albedo values of the asteroids. The measu...

  18. Chang'e-2 spacecraft observations of asteroid 4179 Toutatis

    Science.gov (United States)

    Ji, Jianghui; Jiang, Yun; Zhao, Yuhui; Wang, Su; Yu, Liangliang

    2016-01-01

    On 13 December 2012, Chang'e-2 completed a successful flyby of the near-Earth asteroid 4179 Toutatis at a closest distance of 770 meters from the asteroid's surface. The observations show that Toutatis has an irregular surface and its shape resembles a ginger-root of a smaller lobe (head) and a larger lobe (body). Such bilobate shape is indicative of a contact binary origin for Toutatis. In addition, the high-resolution images better than 3 meters provide a number of new discoveries about this asteroid, such as an 800-meter depression at the end of the large lobe, a sharply perpendicular silhouette near the neck region, boulders, indicating that Toutatis is probably a rubble-pile asteroid. Chang'e-2 observations have significantly revealed new insights into the geological features and the formation and evolution of this asteroid. In final, we brief the future Chinese asteroid mission concept.

  19. Chang'e-2 spacecraft observations of asteroid 4179 Toutatis

    CERN Document Server

    Ji, Jianghui; Zhao, Yuhui; Wang, Su; Yu, Liangliang

    2015-01-01

    On 13 December 2012, Chang'e-2 completed a successful flyby of the near-Earth asteroid 4179 Toutatis at a closest distance of 770 meters from the asteroid's surface. The observations show that Toutatis has an irregular surface and its shape resembles a ginger-root of a smaller lobe (head) and a larger lobe (body). Such bilobate shape is indicative of a contact binary origin for Toutatis. In addition, the high-resolution images better than 3 meters provide a number of new discoveries about this asteroid, such as an 800-meter depression at the end of the large lobe, a sharply perpendicular silhouette near the neck region, boulders, indicating that Toutatis is probably a rubble-pile asteroid. Chang'e-2 observations have significantly revealed new insights into the geological features and the formation and evolution of this asteroid. In final, we brief the future Chinese asteroid mission concept.

  20. Asteroid Deflection Using a Spacecraft in Restricted Keplerian Motion

    CERN Document Server

    Ketema, Yohannes

    2016-01-01

    A method for asteroid deflection that makes use of a spacecraft moving back and forth on a segment of an appropriate Keplerian orbit about the asteroid is described and evaluated. It is shown that, on average, the spacecraft describing such a trajectory can exert a significantly larger force on the asteroid than e.g. a stationary gravity tractor, thereby reducing the time needed to effect a desired velocity change for the asteroid. Furthermore, the current method does not require canted thrusters on the spacecraft (unlike a stationary gravity tractor), markedly reducing the amount of fuel needed to create a given change in the asteroid velocity. In addition, the method allows for the simultaneous use of several spacecraft, further strengthening the overall tugging effect on the asteroid, and distributing the thrust requirement among the spacecraft.

  1. Radar observations of the asteroid 2011 UW158

    Science.gov (United States)

    Ipatov, A. V.; Bondarenko, Yu. S.; Medvedev, Yu. D.; Mishina, N. A.; Marshalov, D. A.; Benner, L. A.

    2016-12-01

    In July 2015 intercontinental bistatic radar observations of the potentially dangerous asteroid 2011 UW158 during its close approach to the Earth were carried out. The asteroid was illuminated at a frequency of 8.4 GHz with the 70-m DSS-14 antenna of the Goldstone Deep Space Communications Complex, while the signal reflected from the asteroid was received with the 32-m radio telescopes of the Quasar VLBI network at the Zelenchukskaya and Badary Observatories. The spectra of the reflected radio signals were obtained. The sizes and rotation period of the asteroid consistent with photometric observations and the ratio of the powers of the reflected signals with left- and right-hand circular polarizations were determined. The derived values suggest that the asteroid has an inhomogeneous surface and a prolate shape. The observations of the Doppler shift of the reflected signal frequency were obtained, which allowed the orbital parameters of the asteroid to be improved.

  2. Small Business Size Standards

    Data.gov (United States)

    Small Business Administration — Certain government programs, such as SBA loan programs and contracting opportunities, are reserved for small business concerns. In order to qualify, businesses must...

  3. Small Business Development Center

    Data.gov (United States)

    Small Business Administration — Small Business Development Centers (SBDCs) provide assistance to small businesses and aspiring entrepreneurs throughout the United States and its territories. SBDCs...

  4. 3382 Cassidy: A Short Period Asteroid

    Science.gov (United States)

    Risley, Ethan

    2013-04-01

    The asteroid 3382 Cassidy was observed from the Etscorn Campus Observatory (ECO, 2012) at New Mexico Institute of Mining and Technology in Socorro, NM, on nine nights over a span of 43 days in 2012 September-November. A bimodal synodic period of 4.254 ± 0.002 h and an amplitude of 0.15 ± 0.02 mag were obtained.

  5. Polarimetry of M-type asteroids

    Science.gov (United States)

    Gil-Hutton, R.

    2007-03-01

    Aims:Results of a polarimetric program at Complejo Astronómico El Leoncito (Casleo), San Juan, Argentina are presented. The aim of this campaign is to estimate the polarimetric properties of asteroids belonging to the X taxonomic class. In this paper results of the campaign for M-type objects are presented. Methods: The data have been obtained with Casprof and Torino polarimeters at the 2.15 m telescope. The Casprof polarimeter is a two-hole aperture polarimeter with rapid modulation and the Torino polarimeter is an instrument that allows simultaneous measurement of polarization in the U-, B-, V-, R-, and I-bands. Results: The campaign began in 2000, and data on a sample of 26 M-type asteroids were obtained. Most of these objects were polarimetricaly observed for the first time. Combining these data with those available in the literature, an estimate of the polarimetric parameters and albedo for 12 objects is presented. Furthermore, the data show that asteroids 21 Lutetia and 77 Frigga have a large inversion angle and 441 Bathilde a deep polarization minimum, implying a controversial taxonomic classification as M-type for these objects. Also, the polarimetric parameters estimated for the M-type asteroids showing in their spectra the 3 μm band and classified as W-type by Rivkin et al. (1995, Icarus, 117, 90; 2000, ApJ, 145, 351) could be different from those without that feature. Based on observations carried out at the Complejo Astronómico El Leoncito, operated under agreement between the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina, and the National Universities of La Plata, Córdoba and San Juan.

  6. Consequences of Predicted or Actual Asteroid Impacts

    Science.gov (United States)

    Chapman, C. R.

    2003-12-01

    Earth impact by an asteroid could have enormous physical and environmental consequences. Impactors larger than 2 km diameter could be so destructive as to threaten civilization. Since such events greatly exceed any other natural or man-made catastrophe, much extrapolation is necessary just to understand environmental implications (e.g. sudden global cooling, tsunami magnitude, toxic effects). Responses of vital elements of the ecosystem (e.g. agriculture) and of human society to such an impact are conjectural. For instance, response to the Blackout of 2003 was restrained, but response to 9/11 terrorism was arguably exaggerated and dysfunctional; would society be fragile or robust in the face of global catastrophe? Even small impacts, or predictions of impacts (accurate or faulty), could generate disproportionate responses, especially if news media reports are hyped or inaccurate or if responsible entities (e.g. military organizations in regions of conflict) are inadequately aware of the phenomenology of small impacts. Asteroid impact is the one geophysical hazard of high potential consequence with which we, fortunately, have essentially no historical experience. It is thus important that decision makers familiarize themselves with the hazard and that society (perhaps using a formal procedure, like a National Academy of Sciences study) evaluate the priority of addressing the hazard by (a) further telescopic searches for dangerous but still-undiscovered asteroids and (b) development of mitigation strategies (including deflection of an oncoming asteroid and on- Earth civil defense). I exemplify these issues by discussing several representative cases that span the range of parameters. Many of the specific physical consequences of impact involve effects like those of other geophysical disasters (flood, fire, earthquake, etc.), but the psychological and sociological aspects of predicted and actual impacts are distinctive. Standard economic cost/benefit analyses may not

  7. Simulations of asteroid impacts on water

    Science.gov (United States)

    Gisler, G. R.; Weaver, R. P.; Gittings, M. L.

    2002-05-01

    We have performed a series of two-dimensional and three-dimensional simulations of asteroid impacts into an ocean using the SAGE code from Los Alamos National Laboratory and Science Applications International Corporation. The SAGE code is a compressible Eulerian hydrodynamics code using continuous adaptive mesh refinement for following discontinuities with a fine grid while treating the bulk of the simulation more coarsely. We have used realistic equations of state for the atmosphere, sea water, the oceanic crust and mantle. In two dimensions, we threw asteroid impactors at 20 km/s vertically through an exponential atmosphere into a 5 km deep ocean. The impactors were composed of mantle material (3.32 g/cc) with diameters of 250m, 500m, and 1000m, chosen to compare with the previous work of Crawford and Mader. We also performed some runs with asteroids composed of iron (7.8 g/cc). Because some of the iron asteroids produced craters that penetrated the basalt crust, we included a layer of mantle material in all simulations. A vertical impact produces a large underwater cavity with nearly vertical walls followed by a collapse starting from the bottom and subsequent vertical jetting. Tsunamis up to a kilometer in initial height were generated and followed out to 100 km from the point of impact. In the three-dimensional run, an impactor of iron was thrown at 20 km/s at an angle of 45 degrees. Differences between this run and the vertical two-dimensional runs will be discussed.

  8. Alien Asteroid Belt Compared to our Own

    Science.gov (United States)

    2005-01-01

    [figure removed for brevity, see original site] Figure 1: Band of Light Comparison This artist's concept illustrates what the night sky might look like from a hypothetical alien planet in a star system with an asteroid belt 25 times as massive as the one in our own solar system (alien system above, ours below; see Figure 1). NASA's Spitzer Space Telescope found evidence for such a belt around the nearby star called HD 69830, when its infrared eyes spotted dust, presumably from asteroids banging together. The telescope did not find any evidence for a planet in the system, but astronomers speculate one or more may be present. The movie begins at dusk on the imaginary world, when HD 69830, like our Sun, has begun to set over the horizon. Time is sped up to show the onset of night and the appearance of a brilliant band of light. This light comes from dust in a massive asteroid belt, which scatters sunlight. In our solar system, anybody observing the skies on a moonless night far from city lights can see the sunlight that is scattered by dust in our asteroid belt. Called zodiacal light and sometimes the 'false dawn,' this light appears as a dim band stretching up from the horizon when the Sun is about to rise or set. The light is faint enough that the disk of our Milky Way galaxy remains the most prominent feature in the sky. (The Milky Way disk is shown perpendicular to the zodiacal light in both pictures.) In contrast, the zodiacal light in the HD 69830 system would be 1,000 times brighter than our own, outshining even the Milky Way.

  9. CCD Photometry of Asteroid (147) Protogeneia

    Institute of Scientific and Technical Information of China (English)

    Xi-Liang Zhang; Xiao-Bin Wang; Li-Yun Zhang

    2006-01-01

    We measured the light-curve of the asteroid (147) Protogeneia in November 2004, with a CCD detector attached to the 1-meter telescope at the Yunnan Observatory, China. The synodic period and maximum amplitude of (147) at this apparition are 7.852 hours and 0.25 mag, respectively. The value of a/b for (147), from a preliminary estimation, is not less than 1.26:1.

  10. Asteroids in the service of humanity

    CERN Document Server

    Crawford, Ian A

    2013-01-01

    There are at least three compelling reasons for the human race to initiate a major programme to explore and better understand the 'minor planets' of the Solar System: (1) Enhancing scientific knowledge; (2) Mitigating the impact hazard; and (3) Utilizing extraterrestrial resources. Strong synergies exist between all three. Moreover, all these activities would benefit from greater international cooperation in space exploration by the World's space agencies, and the recognition that asteroids are important targets for human and robotic exploration.

  11. Curation of Osiris-REx Asteroid Samples

    Science.gov (United States)

    Righter, K.; Nakamura-Messenger, K.; Lauretta, D. S.

    2013-01-01

    The New Frontiers mission, OSIRIS-REx, will encounter carbonaceous asteroid 101955 Bennu (1999 RQ36; [1]) in 2018, collect a sample and return it to Earth and deliver it to NASA-JSC for curation in 2023. The mission curation plan is being developed and an overview will be given, including the main elements of contamination control, sample recovery, cleanroom construction, and curation support once the sample is returned to Earth.

  12. International Asteroid Search Campaign: An Educational Outreach Program in Astronomy for High Schools and Colleges

    Science.gov (United States)

    Miller, J. P.; Juliano, D.; Davis, J. W.; Holmes, R. E.; Devore, H.; Raab, H.; Pennypacker, C. R.; White, G. L.; Gould, A.

    2008-03-01

    The International Asteroid Search Campaign is an Internet-based program for high schools and colleges. Schools receive images, analyzed by students searching for asteroids and NEOs. Students have 71 asteroid discoveries and 1376 NEO observations.

  13. Example Solar Electric Propulsion System asteroid tours using variational calculus

    Science.gov (United States)

    Burrows, R. R.

    1985-01-01

    Exploration of the asteroid belt with a vehicle utilizing a Solar Electric Propulsion System has been proposed in past studies. Some of those studies illustrated multiple asteroid rendezvous with trajectories obtained using approximate methods. Most of the inadequacies of those approximations are overcome in this paper, which uses the calculus of variations to calculate the trajectories and associated payloads of four asteroid tours. The modeling, equations, and solution techniques are discussed, followed by a presentation of the results.

  14. Asteroid Detection Results Using the Space Surveillance Telescope

    Science.gov (United States)

    2015-10-18

    Distribution Statement A: Approved for public release, distribution unlimited. Asteroid Detection Results Using the Space Surveillance Telescope...USA ABSTRACT From 1998-2013, MIT Lincoln Laboratory operated a highly successful near-Earth asteroid search program using...two 1-m optical telescopes located at the MIT Lincoln Laboratory Experimental Test Site (ETS) in Socorro, N.M. In 2014, the Lincoln Near-Earth Asteroid

  15. Design of MGA trajectories for main belt asteroid

    Institute of Scientific and Technical Information of China (English)

    崔祜涛; 乔栋; 崔平远; 栾恩杰

    2003-01-01

    Asteroid exploration is one of the most sophisticated missions currently being investigated. Gravityassist trajectories have proven valuable in interplanetary missions such as the Pioneer, Voyager and Galileo. In this paper, we design interplanetary trajectory for main belt asteroid exploration mission with the Mars gravityassist (MGA) using "pork chop" plots and patched-conic theory and give some initial valuable trajectory parameters on main belt asteroid exploration mission with MGA.

  16. Solar System evolution from compositional mapping of the asteroid belt.

    Science.gov (United States)

    DeMeo, F E; Carry, B

    2014-01-30

    Advances in the discovery and characterization of asteroids over the past decade have revealed an unanticipated underlying structure that points to a dramatic early history of the inner Solar System. The asteroids in the main asteroid belt have been discovered to be more compositionally diverse with size and distance from the Sun than had previously been known. This implies substantial mixing through processes such as planetary migration and the subsequent dynamical processes.

  17. Exploring adolescents' perceptions of risky behaviour using the mobile phone / N. Gois De Gouveia.

    OpenAIRE

    De Gouveia, Natalie Gois

    2013-01-01

    The aim of this study was to examine adolescent perceptions of risky behaviour using a mobile phone. This research may contribute to creating an awareness of risky and healthy adolescent uses of mobile phones. Anonymous sketches were collected from Grade 10 learners depicting their understanding of risky behaviour using the mobile phone. Thereafter, 12 learners agreed, through informed consent, to participate in semi-structured interviews. All participants considered the mobile phone an i...

  18. How Beliefs about HIV Status Affect Risky Behaviors: Evidence from Malawi

    OpenAIRE

    De Paula, A.; Shapira, G.; Todd, P. E.

    2008-01-01

    This paper examines how beliefs about own HIV status affect decisions to engage in risky sexual behavior, as measured by having extramarital sex and/or multiple sex partners. The empirical analysis is based on a panel survey of males from the 2006 and 2008 rounds of the Malawi Diffusion and Ideational Change Project (MDICP). The paper develops a behavioral model of the belief-risky behavior relationship and estimates the causal effect of beliefs on risky behavior using the Arellano and Carras...

  19. Adolescents' Neural Processing of Risky Decisions: Effects of Sex and Behavioral Disinhibition.

    Directory of Open Access Journals (Sweden)

    Thomas J Crowley

    Full Text Available Accidental injury and homicide, relatively common among adolescents, often follow risky behaviors; those are done more by boys and by adolescents with greater behavioral disinhibition (BD.Neural processing during adolescents' risky decision-making will differ in youths with greater BD severity, and in males vs. females, both before cautious behaviors and before risky behaviors.81 adolescents (PATIENTS with substance and conduct problems, and comparison youths (Comparisons, assessed in a 2 x 2 design (Comparisons x Male:Female repeatedly decided between doing a cautious behavior that earned 1 cent, or a risky one that either won 5 or lost 10 cents. Odds of winning after risky responses gradually decreased. Functional magnetic resonance imaging captured brain activity during 4-sec deliberation periods preceding responses. Most neural activation appeared in known decision-making structures. PATIENTS, who had more severe BD scores and clinical problems than Comparisons, also had extensive neural hypoactivity. Comparisons' greater activation before cautious responses included frontal pole, medial prefrontal cortex, striatum, and other regions; and before risky responses, insula, temporal, and parietal regions. Males made more risky and fewer cautious responses than females, but before cautious responses males activated numerous regions more than females. Before risky behaviors female-greater activation was more posterior, and male-greater more anterior.Neural processing differences during risky-cautious decision-making may underlie group differences in adolescents' substance-related and antisocial risk-taking. Patients reported harmful real-life decisions and showed extensive neural hypoactivity during risky-or-cautious decision-making. Males made more risky responses than females; apparently biased toward risky decisions, males (compared with females utilized many more neural resources to make and maintain cautious decisions, indicating an important

  20. Children's Risky Play from an Evolutionary Perspective: The Anti-Phobic Effects of Thrilling Experiences

    OpenAIRE

    Ellen Beate Hansen Sandseter; Leif Edward Ottesen Kennair

    2011-01-01

    This theoretical article views children's risky play from an evolutionary perspective, addressing specific evolutionary functions and especially the anti-phobic effects of risky play. According to the non-associative theory, a contemporary approach to the etiology of anxiety, children develop fears of certain stimuli (e.g., heights and strangers) that protect them from situations they are not mature enough to cope with, naturally through infancy. Risky play is a set of motivated behaviors tha...

  1. The small binary asteroid (939) Isberga

    CERN Document Server

    Carry, B; Scheirich, P; Pravec, P; Molnar, L; Mottola, S; Carbognani, A; Jehin, E; Marciniak, A; Binzel, R P; DeMeo, F E; Birlan, M; Delbo, M; Barbotin, E; Behrend, R; Bonnardeau, M; Colas, F; Farissier, P; Fauvaud, M; Fauvaud, S; Gillier, C; Gillon, M; Hellmich, S; Hirsch, R; Leroy, A; Manfroid, J; Montier, J; Morelle, E; Richard, F; Sobkowiak, K; Strajnic, J; Vachier, F

    2014-01-01

    In understanding the composition and internal structure of asteroids, their density is perhaps the most diagnostic quantity. We aim here to characterize the surface composition, mutual orbit, size, mass, and density of the small main-belt binary asteroid (939) Isberga. For that, we conduct a suite of multi-technique observations, including optical lightcurves over many epochs, near-infrared spectroscopy, and interferometry in the thermal infrared. We develop a simple geometric model of binary systems to analyze the interferometric data in combination with the results of the lightcurve modeling. From spectroscopy, we classify Ibserga as a Sq-type asteroid, consistent with the albedo of 0.14$^{+0.09}_{-0.06}$ (all uncertainties are reported as 3-$\\sigma$ range) we determine (average albedo of S-types is 0.197 $\\pm$ 0.153, Pravec et al., 2012, Icarus 221, 365-387). Lightcurve analysis reveals that the mutual orbit has a period of 26.6304 $\\pm$ 0.0001 h, is close to circular, and has pole coordinates within 7 deg...

  2. Spacewatch discovery of near-Earth asteroids

    Science.gov (United States)

    Gehrels, Tom

    1992-01-01

    Our overall scientific goal is to survey the solar system to completion - that is, to find the various populations and to study their statistics, interrelations, and origins. The practical benefit to SERC is that we are finding Earth-approaching asteroids that are accessible for mining. Our system can detect Earth-approachers in the 1-km size range even when they are far away, and can detect smaller objects when they are moving rapidly past Earth. Until Spacewatch, the size range of 6-300 meters in diameter for the near-Earth asteroids was unexplored. This important region represents the transition between the meteorites and the larger observed near-Earth asteroids. One of our Spacewatch discoveries, 1991 VG, may be representative of a new orbital class of object. If it is really a natural object, and not man-made, its orbital parameters are closer to those of the Earth than we have seen before; its delta V is the lowest of all objects known thus far. We may expect new discoveries as we continue our surveying, with fine-tuning of the techniques.

  3. The preventive destruction of a hazardous asteroid

    Science.gov (United States)

    Aleksandrova, A. G.; Galushina, T. Yu.; Prishchepenko, A. B.; Kholshevnikov, K. V.; Chechetkin, V. M.

    2016-06-01

    One means of countering a hazardous asteroid is discussed: destruction of the object using a nuclear charge. Explosion of such an asteroid shortly before its predicted collision would have catastrophic consequences, with numerous highly radioactive fragments falling onto the Earth. The possibility of exploding the asteroid several years before its impact is also considered. Such an approach is made feasible because the vast majority of hazardous objects pass by the Earth several times before colliding with it. Computations show that, in the 10 years following the explosion, only a negligible number of fragments fall onto the Earth, whose radioactivity has substantially reduced during this time. In most cases, none of these fragments collides with the Earth. Thus, this proposed method for eliminating a threat from space is reasonable in at least two cases: when it is not possible to undergo a soft removal of the object from the collisional path, and to destroy objects that are continually returning to near-Earth space and require multiple removals from hazardous orbits.

  4. A Probabilistic Asteroid Impact Risk Model

    Science.gov (United States)

    Mathias, Donovan L.; Wheeler, Lorien F.; Dotson, Jessie L.

    2016-01-01

    Asteroid threat assessment requires the quantification of both the impact likelihood and resulting consequence across the range of possible events. This paper presents a probabilistic asteroid impact risk (PAIR) assessment model developed for this purpose. The model incorporates published impact frequency rates with state-of-the-art consequence assessment tools, applied within a Monte Carlo framework that generates sets of impact scenarios from uncertain parameter distributions. Explicit treatment of atmospheric entry is included to produce energy deposition rates that account for the effects of thermal ablation and object fragmentation. These energy deposition rates are used to model the resulting ground damage, and affected populations are computed for the sampled impact locations. The results for each scenario are aggregated into a distribution of potential outcomes that reflect the range of uncertain impact parameters, population densities, and strike probabilities. As an illustration of the utility of the PAIR model, the results are used to address the question of what minimum size asteroid constitutes a threat to the population. To answer this question, complete distributions of results are combined with a hypothetical risk tolerance posture to provide the minimum size, given sets of initial assumptions. Model outputs demonstrate how such questions can be answered and provide a means for interpreting the effect that input assumptions and uncertainty can have on final risk-based decisions. Model results can be used to prioritize investments to gain knowledge in critical areas or, conversely, to identify areas where additional data has little effect on the metrics of interest.

  5. Dynamical evolution of the Cybele asteroids

    CERN Document Server

    Carruba, Valerio; Aljbaae, Safwan; Huaman, Mariela Espinoza

    2015-01-01

    The Cybele region, located between the 2J:-1A and 5J:-3A mean-motion resonances, is adjacent and exterior to the asteroid main belt. An increasing density of three-body resonances makes the region between the Cybele and Hilda populations dynamically unstable, so that the Cybele zone could be considered the last outpost of an extended main belt. The presence of binary asteroids with large primaries and small secondaries suggested that asteroid families should be found in this region, but only relatively recently the first dynamical groups were identified in this area. Among these, the Sylvia group has been proposed to be one of the oldest families in the extended main belt. In this work we identify families in the Cybele region in the context of the local dynamics and non-gravitational forces such as the Yarkovsky and stochastic YORP effects. We confirm the detection of the new Helga group at $\\simeq$3.65~AU, that could extend the outer boundary of the Cybele region up to the 5J:-3A mean-motion resonance. We o...

  6. How to find metal-rich asteroids

    CERN Document Server

    Harris, Alan W

    2014-01-01

    The metal content of asteroids is of great interest, not only for theories of their origins and the evolution of the solar system but, in the case of near-Earth objects (NEOs), also for impact mitigation planning and endeavors in the field of planetary resources. However, since the reflection spectra of metallic asteroids are largely featureless, it is difficult to identify them and relatively few are known. We show how data from the Wide-field Infrared Survey Explorer (WISE)/NEOWISE thermal-infrared survey and similar surveys, fitted with a simple thermal model, can reveal objects likely to be metal rich. We provide a list of candidate metal-rich NEOs. Our results imply that future infrared surveys with the appropriate instrumentation could discover many more metal-rich asteroids, providing valuable data for assessment of the impact hazard and the potential of NEOs as reservoirs of vital materials for future interplanetary space activities and, eventually perhaps, for use on Earth.

  7. Formation and Evolution of Binary Asteroids

    CERN Document Server

    Walsh, Kevin J

    2015-01-01

    Satellites of asteroids have been discovered in nearly every known small body population, and a remarkable aspect of the known satellites is the diversity of their properties. They tell a story of vast differences in formation and evolution mechanisms that act as a function of size, distance from the Sun, and the properties of their nebular environment at the beginning of Solar System history and their dynamical environment over the next 4.5 Gyr. The mere existence of these systems provides a laboratory to study numerous types of physical processes acting on asteroids and their dynamics provide a valuable probe of their physical properties otherwise possible only with spacecraft. Advances in understanding the formation and evolution of binary systems have been assisted by: 1) the growing catalog of known systems, increasing from 33 to nearly 250 between the Merline et al. (2002) Asteroids III chapter and now, 2) the detailed study and long-term monitoring of individual systems such as 1999 KW4 and 1996 FG3, 3...

  8. Naming asteroids for the popularisation of astronomy

    Science.gov (United States)

    Naranjo, O. A.

    2008-06-01

    We give a detailed description of how the naming of asteroids was used as a prize in competitions run by educational institutions and museums. There were two events, one in Venezuela and one in Brazil, which used this as an attractive alternative method for the popularisation of astronomy. The first competition, named Bautizo Espacial (Space Baptism), consisted of scientific stories written by high school students. The second, called Grande Desafio (Big Challenge), was a competition where teams of students were challenged to design and build prototype equipment to fight forest fires. Nationally, both events received wide publicity through newspapers, radio, TV and web pages, reaching many people in both countries. As part of both the events, several activities promoting the public knowledge of astronomy were held. The asteroids that were named in these competitions are just some of the many discovered in a search programme developed by the Group of Theoretical Astrophysics of University of Los Andes in Mérida, Venezuela (Grupo de Astrofisica Teórica de la Universidad de Los Andes) as a mainstream research programme. Finally, Asteroids for the Popularisation of Astronomy has been formally proposed to the IAU as a worldwide programme during the celebration of the International Year of Astronomy in 2009 (IYA2009).

  9. Progress in clinical research of asteroid hyalosis

    Directory of Open Access Journals (Sweden)

    Xiao-Xue Liu

    2017-08-01

    Full Text Available Asteroid Hyalosis(AHis a common clinical disease, which has been considered a benign disorder as it rarely impairs visual acuity. It was often discovered when the patient was treated for other eye diseases. The mechanism was unclear. Its characteristic B-ultrasound property makes the B-ultrasound a very helpful diagnostic technique. In the case of the patients with other fundus diseases associated with AH, optical coherence tomography(OCTand fluorescein angiography(FAmay be used to reduce the interference from asteroid bodies, therefore improve the fundus visibility. Recent studies have shown that AH can incorporate with many other eye diseases. For example, in patients with cataracts, asteroid hyalosis can cause surface calcification of silicone plate intraocular lenses, which in most cases may lead to the need for explantation of the calcified intraocular lenses. The efficacy of pars plana vitrectomy(PPV, the removal of some, or all, of the eye's vitreous humor for AH remains controversial. In this paper, we provide a review of the recent literature on AH disease: the etiology, diagnosis and treatment. We hope to thus improve the awareness and outcomes of AH disease.

  10. How Many Ore-Bearing Asteroids?

    CERN Document Server

    Elvis, Martin

    2013-01-01

    A simple formalism is presented to assess how many asteroids contain ore, i.e. commercially profitable material, and not merely a high concentration of a resource. I apply this formalism to two resource cases: platinum group metals (PGMs) and water. Assuming for now that only Ni-Fe asteroids are of interest for PGMs, then 1% of NEOs are rich in PGMs. The dearth of ultra-low delta-v (= US$1 B and the population of near-Earth objects (NEOs) larger than 100 m diameter is ~20,000 (Mainzer et al. 2011) the total population of PGM ore-bearing NEOs is roughly 10. I stress that this is a conservative and highly uncertain value. For example, an order of magnitude increase in PGM ore-bearing NEOs occurs if delta-v can as large as 5.7 km s-1. Water ore for utilization in space is likely to be found in ~1/1100 NEOs. NEOs as small as 18 m diameter can be water-ore-bodies because of the high richness of water (~20%) expected in ~25% of carbonaceous asteroids, bringing the number of water-ore-bearing NEOs to ~9000 out of th...

  11. The Cratering History of Asteroid (2867) Steins

    CERN Document Server

    Marchi, S; Kueppers, M; Marzari, F; Davidsson, B; Keller, H U; Besse, S; Lamy, P; Mottola, S; Massironi, M; Cremonese, G

    2010-01-01

    The cratering history of main belt asteroid (2867) Steins has been investigated using OSIRIS imagery acquired during the Rosetta flyby that took place on the 5th of September 2008. For this purpose, we applied current models describing the formation and evolution of main belt asteroids, that provide the rate and velocity distributions of impactors. These models coupled with appropriate crater scaling laws, allow the cratering history to be estimated. Hence, we derive Steins' cratering retention age, namely the time lapsed since its formation or global surface reset. We also investigate the influence of various factors -like bulk structure and crater erasing- on the estimated age, which spans from a few hundred Myrs to more than 1Gyr, depending on the adopted scaling law and asteroid physical parameters. Moreover, a marked lack of craters smaller than about 0.6km has been found and interpreted as a result of a peculiar evolution of Steins cratering record, possibly related either to the formation of the 2.1km ...

  12. Business Intelligence

    OpenAIRE

    Strejčková, Lucie

    2006-01-01

    Cílem této bakalářské práce je seznámení s Business Intelligence a zpracování vývojového trendu, který ovlivňuje podobu řešení Business Intelligence v podniku ? Business Activity Monitoring. Pro zpracování tohoto tématu byla použita metoda studia odborných pramenů, a to jak v českém, tak v anglickém jazyce. Hlavním přínosem práce je ucelený, v českém jazyce zpracovaný materiál pojednávající o Business Activity Monitoring. Práce je rozdělena do šesti hlavních kapitol. Prvních pět je věnováno p...

  13. Business link

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Baotou Hongbo technology Co.,Ltd was registered in Baotou Rare Earth High-Tech Development Zone in 2008.The company is integrated with scientific research and development,production and trade business.Main products include individual and mixed light rare earth salts,oxides and metals,phosphors and so on.

  14. Business Intelligence

    OpenAIRE

    Strejčková, Lucie

    2001-01-01

    Cílem této bakalářské práce je seznámení s Business Intelligence a zpracování vývojového trendu, který ovlivňuje podobu řešení Business Intelligence v podniku ? Business Activity Monitoring. Pro zpracování tohoto tématu byla použita metoda studia odborných pramenů, a to jak v českém, tak v anglickém jazyce. Hlavním přínosem práce je ucelený, v českém jazyce zpracovaný materiál pojednávající o Business Activity Monitoring. Práce je rozdělena do šesti hlavních kapitol. Prvních pět je věnováno p...

  15. Business History

    DEFF Research Database (Denmark)

    Hansen, Per H.

    2012-01-01

    This article argues that a cultural and narrative perspective can enrich the business history field, encourage new and different questions and answers, and provide new ways of thinking about methods and empirical material. It discusses what culture is and how it relates to narratives. Taking...

  16. Business Leksikon

    DEFF Research Database (Denmark)

    Nielsen, Sandro

    2002-01-01

    This review article deals with a specialised dictionary recently introduced to the Danish market. It covers traditional business subjects and is designed for semi-experts and laypeople. Through Danish definitions and English, French and German equivalents, it aims at fulfilling the functions text...

  17. Scary Business

    DEFF Research Database (Denmark)

    Platts, Todd; Clasen, Mathias

    2017-01-01

    Despite horror films representing business ventures intended to turn profit, box office analyses of the genre have remained rare in scholarly literature. Our study fills that gap through an examination of 117 horror films that reached the top 100 in domestic grosses in the North American film...

  18. Unfinished Business

    Science.gov (United States)

    Tuckett, Alan

    2011-01-01

    Adult learning is not a tidy business: adults fit learning into the spaces left by the other demands on complex lives, and into the spaces left in administrative structures overwhelmingly designed for other people. No simple metric can capture adults' diverse purposes and achievements, and no single programme can capture the full range of things…

  19. Business Blooming

    Institute of Scientific and Technical Information of China (English)

    MARK GRAHAM

    2008-01-01

    @@ Florist Sebastien Lathuile was in no doubt of the business potential in Shanghai from the moment he arrived on a personal visit, some five years ago. The Frenchman returned immediately home to London,where he had been working,put his flat on the market, and began making plans to set up in the east-coast city.

  20. Photometry and models of selected main belt asteroids: IX. Introducing interactive service for asteroid models (ISAM)

    DEFF Research Database (Denmark)

    Marciniak, A.; Bartczak, P.; Santana-Ros, T.

    2012-01-01

    from other observing/modelling techniques, we created an on-line service where we allow the inversion models to be orientated interactively. Results. Our sample of objects is quite representative, containing both relatively fast and slow rotators with highly and lowly inclined spin axes. With this work...... occultations, or space probe imaging. Aims. During our ongoing work to increase the set of asteroids with known spin and shape parameters, there appeared a need for displaying the model plane-of-sky orientations for specific epochs to compare models from different techniques. It would also be instructive...... to be able to track how the complex lightcurves are produced by various asteroid shapes. Methods. Basing our analysis on an extensive photometric observational dataset, we obtained eight asteroid models with the convex lightcurve inversion method. To enable comparison of the photometric models with those...

  1. Polarization of asteroid (387) Aquitania: the newest member of a class of large inversion angle asteroids

    CERN Document Server

    Masiero, Joseph

    2008-01-01

    We present new imaging polarimetric observations of two Main Belt asteroids, (234) Barbara and (387) Aquitania, taken in the first half of 2008 using the Dual-Beam Imaging Polarimeter on the University of Hawaii 2.2 meter telescope, located on Mauna Kea, Hawaii. Barbara had been previously shown to exhibit a very unusual polarization-phase curve by Cellino, et al. (2006). Our observations confirm this result and add Aquitania to the growing class of large inversion angle objects. Interestingly, these asteroids show spinel features in their IR spectra suggesting a mineralogical origin to the phase angle-dependent polarimetric features. As spinel is associated with calcium-aluminum-rich inclusions and carbonaceous chondrites, these large inversion angle asteroids may represent some of the oldest surfaces in the solar system. Circular as well as linear polarization measurements were obtained but circular polarization was not detected.

  2. A fast ellipsoid model for asteroids inverted from lightcurves

    Institute of Scientific and Technical Information of China (English)

    Xiao-Ping Lu; Hai-Bin Zhao; Zhong You

    2013-01-01

    Research about asteroids has recently attracted more and more attention,especially focusing on their physical structures,such as their spin axis,rotation period and shape.The long distance between observers on Earth and asteroids makes it impossible to directly calculate the shape and other parameters of asteroids,with the exception of Near Earth Asteroids and others that have passed by some spacecrafts.Photometric measurements are still generally the main way to obtain research data on asteroids,i.e.the lightcurves recording the brightness and positions of asteroids.Supposing that the shape of the asteroid is a triaxial ellipsoid with a stable spin,a new method is presented in this article to reconstruct the shape models of asteroids from the lightcurves,together with other physical parameters.By applying a special curvature function,the method calculates the brightness integration on a unit sphere and Lebedev quadrature is employed for the discretization.Finally,the method searches for the optimal solution by the Levenberg-Marquardt algorithm to minimize the residual of the brightness.By adopting this method,not only can related physical parameters of asteroids be obtained at a reasonable accuracy,but also a simple shape model of an ellipsoid can be generated for reconstructing a more sophisticated shape model.

  3. The Nature of C Asteroid Regolith from Meteorite Observations

    Science.gov (United States)

    Zolensky, M.; Mikouchi, T.; Hagiya, K.; Ohsumi, K.; Komatsu, M.; Jenniskens, P.; Le, L.; Yin, Q.-Z; Kebukawa, Y.; Fries, M.

    2013-01-01

    Regolith from C (and related) asteroid bodies are a focus of the current missions Dawn at Ceres, Hayabusa 2 and OSIRIS REx. An asteroid as large as Ceres is expected to be covered by a mature regolith, and as Hayabusa demonstrated, flat and therefore engineeringly-safe ponded deposits will probably be the sampling sites for both Hayabusa 2 and OSIRIS REx. Here we examine what we have learned about the mineralogy of fine-grained asteroid regolith from recent meteorite studies and the examination of the samples harvested from asteroid Itokawa by Hayabusa.

  4. What is the Relationship between Risky Outdoor Play and Health in Children? A Systematic Review

    Directory of Open Access Journals (Sweden)

    Mariana Brussoni

    2015-06-01

    Full Text Available Risky outdoor play has been associated with promoting children’s health and development, but also with injury and death. Risky outdoor play has diminished over time, concurrent with increasing concerns regarding child safety and emphasis on injury prevention. We sought to conduct a systematic review to examine the relationship between risky outdoor play and health in children, in order to inform the debate regarding its benefits and harms. We identified and evaluated 21 relevant papers for quality using the GRADE framework. Included articles addressed the effect on health indicators and behaviours from three types of risky play, as well as risky play supportive environments. The systematic review revealed overall positive effects of risky outdoor play on a variety of health indicators and behaviours, most commonly physical activity, but also social health and behaviours, injuries, and aggression. The review indicated the need for additional “good quality” studies; however, we note that even in the face of the generally exclusionary systematic review process, our findings support the promotion of risky outdoor play for healthy child development. These positive results with the marked reduction in risky outdoor play opportunities in recent generations indicate the need to encourage action to support children’s risky outdoor play opportunities. Policy and practice precedents and recommendations for action are discussed.

  5. The discrepancy between risky and riskless utilities: a matter of framing?

    Science.gov (United States)

    Stalmeier, P F; Bezembinder, T G

    1999-01-01

    Utilities differ according to whether they are derived from risky (gamble) and riskless (visual analog scale, time-tradeoff) assessment methods. The discrepancies are usually explained by assuming that the utilities elicited by risky methods incorporate attitudes towards risk, whereas riskless utilities do not. In (cumulative) prospect theory, risk attitude is conceived as consisting of two components: a decision-weight function (attentiveness to changes in, or sensitivity towards, chance) and a utility function (sensitivity towards outcomes). The authors' data suggest that a framing effect is a hitherto unrecognized and important factor in causing discrepancies between risky and riskless utilities. They collected risky evaluations with the gamble method, and riskless evaluations with difference measurement. Risky utilities were derived using expected-utility theory and prospect theory. With the latter approach, sensitivity towards outcomes and sensitivity towards chance are modeled separately. When the hypothesis that risky utilities from prospect theory coincide with riskless utilities was tested, it was rejected (n = 8, F(1,7) = 132, p = 0.000), suggesting that a correction for sensitivity towards chance is not sufficient to resolve the difference between risky and riskless utilities. Next, it was assumed that different gain/loss frames are induced by risky and riskless elicitation methods. Indeed, identical utility functions were obtained when the gain/loss frames were made identical across methods (n = 7), suggesting that framing was operative. The results suggest that risky and riskless utilities are identical after corrections for sensitivity towards chance and framing.

  6. What is the Relationship between Risky Outdoor Play and Health in Children? A Systematic Review.

    Science.gov (United States)

    Brussoni, Mariana; Gibbons, Rebecca; Gray, Casey; Ishikawa, Takuro; Sandseter, Ellen Beate Hansen; Bienenstock, Adam; Chabot, Guylaine; Fuselli, Pamela; Herrington, Susan; Janssen, Ian; Pickett, William; Power, Marlene; Stanger, Nick; Sampson, Margaret; Tremblay, Mark S

    2015-06-08

    Risky outdoor play has been associated with promoting children's health and development, but also with injury and death. Risky outdoor play has diminished over time, concurrent with increasing concerns regarding child safety and emphasis on injury prevention. We sought to conduct a systematic review to examine the relationship between risky outdoor play and health in children, in order to inform the debate regarding its benefits and harms. We identified and evaluated 21 relevant papers for quality using the GRADE framework. Included articles addressed the effect on health indicators and behaviours from three types of risky play, as well as risky play supportive environments. The systematic review revealed overall positive effects of risky outdoor play on a variety of health indicators and behaviours, most commonly physical activity, but also social health and behaviours, injuries, and aggression. The review indicated the need for additional "good quality" studies; however, we note that even in the face of the generally exclusionary systematic review process, our findings support the promotion of risky outdoor play for healthy child development. These positive results with the marked reduction in risky outdoor play opportunities in recent generations indicate the need to encourage action to support children's risky outdoor play opportunities. Policy and practice precedents and recommendations for action are discussed.

  7. The Role of Impulsivity in the Relation Between Negative Affect and Risky Sexual Behaviors.

    Science.gov (United States)

    Jardin, Charles; Sharp, Carla; Garey, Lorra; Zvolensky, Michael J

    2017-04-03

    While risky sexual behavior associates with negative affect, and impulsivity often increases during negative affective states, little is known about the interrelations of these factors. This study examined whether impulsivity explained the relation between negative affect and risky sex among college students. Negative affect exhibited an indirect effect via impulsivity on number of sexual partners for both males and females, and on inconsistent condom use for females, but not males. Results suggest risky sex may serve to regulate negative affect, proposing the importance of negative affect in future strategies to reduce risky sex among young adults.

  8. Thermal History of Near-Earth Asteroids: Implications for OSIRIS-REx Asteroid Sample Return

    Science.gov (United States)

    Springmann, Alessondra; Lauretta, Dante S.

    2016-10-01

    The connection between orbital and temperature history of small Solar System bodies has only been studied through modeling. The upcoming OSIRIS-REx asteroid sample return mission provides an opportunity to connect thermal modeling predictions with laboratory studies of meteorites to predict past heating and thus dynamical histories of bodies such as OSIRIS-REx mission target asteroid (101955) Bennu. Bennu is a desirable target for asteroid sample return due to its inferred primitive nature, likely 4.5 Gyr old, with chemistry and mineralogy established in the first 10 Myr of solar system history (Lauretta et al. 2015). Delbo & Michel (2011) studied connections between the temperature and orbital history of Bennu. Their results suggest that the surface of Bennu (assuming no regolith turnover) has a 50% probability of being heated to 500 K in the past. Further, the Delbo & Michel simulations show that the temperature within the asteroid below the top layer of regolith could remain at temperatures ~100 K below that of the surface. The Touch-And-Go Sample Acquisition Mechanism on OSIRIS-REx could access both the surface and near surface regolith, collecting primitive asteroid material for study in Earth-based laboratories in 2023. To quantify the effects of thermal metamorphism on the Bennu regolith, laboratory heating experiments on carbonaceous chondrite meteorites with compositions likely similar to that of Bennu were conducted from 300-1200 K. These experiments show mobilization and volatilization of a suite of labile elements (sulfur, mercury, arsenic, tellurium, selenium, antimony, and cadmium) at temperatures that could be reached by asteroids that cross Mercury's orbit. We are able to quantify element loss with temperature for several carbonaceous chondrites and use these results to constrain past orbital histories of Bennu. When OSIRIS-REx samples arrive for analysis we will be able to measure labile element loss in the material, determine maximum past

  9. BUSINESS ECOSYSTEMS VS BUSINESS DIGITAL ECOSYSTEMS

    OpenAIRE

    Marinela Lazarica

    2006-01-01

    E-business is often described as the small organisations’ gateway to global business and markets. The adoption of Internet-based technologies for e-business is a continuous process, with sequential steps of evolution. The latter step in the adoption of Internet-based technologies for business, where the business services and the software components are supported by a pervasive software environment, which shows an evolutionary and self-organising behaviour are named digital business ecosyste...

  10. BUSINESS ETHICS STANDARDS AND HOTEL BUSINESS

    OpenAIRE

    Ivica Batinić

    2014-01-01

    By implementing certain standards in business, especially the standards of business ethics, each entity in the hotel industry emphasize its specificity and recognition, while giving a guestconsumer security and a guarantee that they will get desired quality. In today's global world, business ethics has become an indispensable part of the hotel business practices and prerequisite for achieving business success. Business ethics receives strategic significance because ...

  11. Synchronizing Business & Systems with Business Objects

    OpenAIRE

    Saha, Pallab; Srinivasan, R.

    2001-01-01

    More and more businesses are becoming highly dependent on their information systems (IS) to operate and manage themselves. This necessitates a formal methodology to express business concepts, business processes and events that both business managers and IS professionals can understand and communicate with. The result of this understanding can be quick correction of business systems and operations that are more efficient. This paper introduces the concepts and uses of business objects and outl...

  12. Rotation Induced Disruption of Cohesive Asteroids

    Science.gov (United States)

    Sanchez Lana, Diego; Scheeres, D. J.

    2013-10-01

    We use a Soft-Sphere Discrete Element Method (SSDEM) code to study the evolution of self-gravitating cohesive granular aggregates that are spun to disruption as a proxy to "rubble-pile" asteroids. Calculations have shown that the fine regolith in asteroids and molecular Van der Waals forces together may act as a cohesive matrix that provides enough structural strength to hold small NEAs together even at the observed high spin rates. With this in mind we have implemented cohesive forces between the large 10 m) particles that form our aggregates; its strength being controlled by the mean particle size of the matrix. The addition of rolling friction also has allowed us to obtain cohesionless aggregates with friction angles of at least 35° as measured by the Drucker-Prager yield criterion. A series of experiments were run with the code, keeping the size, density and number of grains constant while increasing the cohesive strength of the matrix holding the grains in place. It can be shown, through a scaling analysis, that when the cohesive strength between rubble pile components is increased by a factor of f, that the effective size of the asteroid being modeled will decrease by a factor of 1/√f. To evaluate this we ran a series of 12 cases with increasing cohesive strength, effectively modeling rubble piles of size from 0.1 km up to 100 km with a constant cohesive strength of 25 Pa. Some of our main results are as follows: 1. results from simulations are compatible with a simple model of asteroid strength that predicts, in the cohesion dominated case, that the spin rate for fission is inversely proportional to the size of the asteroid; 2. aggregates may disrupt by shedding or fission, depending on the cohesive strength and the size of the aggregate (shape and heterogeneity factors have not yet been considered); 3. disruption by fission is more likely for small aggregates than for larger aggregates with the same cohesive strength. Further results with spherical and a

  13. Risky Zoographies: The Limits of Place in Avian Flu Management

    Directory of Open Access Journals (Sweden)

    Natalie Porter

    2012-11-01

    Full Text Available Global anxieties about avian influenza stem from a growing recognition that highly-virulent, highly-mobile disease vectors infiltrate human spaces in ways that are difficult to perceive, and even more difficult to manage. This article analyses a participatory health intervention in Việt Nam to explore how avian influenza threats challenge long-held understandings of animals’ place in the environment and society. In this intervention, poultry farmers collaborated with health workers to illustrate maps of avian flu risks in their communities. Participant-observation of the risk-mapping exercises shows that health workers treated poultry as commodities, and located these animals in environments that could be transformed and dominated by humans. However, these maps did not sufficiently represent the physical and social landscapes where humans and poultry coexist in Việt Nam. As such, farmers located poultry in environments dominated by risky nonhuman forces such as winds, waterways, and other organisms. I argue that these divergent risk maps demonstrate how ecological factors, interpersonal networks, and global market dynamics combine to engender a variety of interspecies relationships, which in turn shape the location of disease risks in space. I develop the term risky zoographies to signal the emergence of competing descriptions of animals and their habitats in zoonotic disease contexts. This concept suggests that as wild animals, livestock products, and microbial pathogens continue to globalise, place-based health interventions that limit animals to particular locales are proving inadequate. Risky zoographies signal the inextricability of nonhuman animals from human spaces, and reveal interspecies interactions that transect and transcend environments.

  14. Job characteristics, well-being and risky behaviour amongst pharmacists.

    Science.gov (United States)

    Phipps, Denham L; Walshe, Kieran; Parker, Dianne; Noyce, Peter R; Ashcroft, Darren M

    2016-12-01

    Healthcare practitioners' fitness to practise has often been linked to their personal and demographic characteristics. It is possible that situational factors, such as the work environment and physical or psychological well-being, also have an influence on an individual's fitness to practise. However, it is unclear how these factors might be linked to behaviours that risk compromising fitness to practise. The aim of this study was to examine the association between job characteristics, well-being and behaviour reflecting risky practice amongst a sample of registered pharmacists in a region of the United Kingdom. Data were obtained from a cross-sectional self-report survey of 517 pharmacists. These data were subjected to principal component analysis and path analysis, with job characteristics (demand, autonomy and feedback) and well-being (distress and perceived competence) as the predictors and behaviour as the outcome variable. Two aspects of behaviour were found: Overloading (taking on more work than one can comfortably manage) and risk taking (working at or beyond boundaries of safe practice). Separate path models including either job characteristics or well-being as independent variables provided a good fit to the data-set. Of the job characteristics, demand had the strongest association with behaviour, while the association between well-being and risky behaviour differed according to the aspect of behaviour being assessed. The findings suggest that, in general terms, situational factors should be considered alongside personal factors when assessing, judging or remediating fitness to practise. They also suggest the presence of different facets to the relationship between job characteristics, well-being and risky behaviour amongst pharmacists.

  15. BUSINESS ECOSYSTEMS VS BUSINESS DIGITAL ECOSYSTEMS

    Directory of Open Access Journals (Sweden)

    Marinela Lazarica

    2006-05-01

    Full Text Available E-business is often described as the small organisations’ gateway to global business and markets. The adoption of Internet-based technologies for e-business is a continuous process, with sequential steps of evolution. The latter step in the adoption of Internet-based technologies for business, where the business services and the software components are supported by a pervasive software environment, which shows an evolutionary and self-organising behaviour are named digital business ecosystems. The digital business ecosystems are characterized by intelligent software components and services, knowledge transfer, interactive training frameworks and integration of business processes and e-government models.

  16. Your resting brain CAREs about your risky behavior.

    Directory of Open Access Journals (Sweden)

    Christine L Cox

    Full Text Available BACKGROUND: Research on the neural correlates of risk-related behaviors and personality traits has provided insight into mechanisms underlying both normal and pathological decision-making. Task-based neuroimaging studies implicate a distributed network of brain regions in risky decision-making. What remains to be understood are the interactions between these regions and their relation to individual differences in personality variables associated with real-world risk-taking. METHODOLOGY/PRINCIPAL FINDINGS: We employed resting state functional magnetic resonance imaging (R-fMRI and resting state functional connectivity (RSFC methods to investigate differences in the brain's intrinsic functional architecture associated with beliefs about the consequences of risky behavior. We obtained an individual measure of expected benefit from engaging in risky behavior, indicating a risk seeking or risk-averse personality, for each of 21 participants from whom we also collected a series of R-fMRI scans. The expected benefit scores were entered in statistical models assessing the RSFC of brain regions consistently implicated in both the evaluation of risk and reward, and cognitive control (i.e., orbitofrontal cortex, nucleus accumbens, lateral prefrontal cortex, dorsal anterior cingulate. We specifically focused on significant brain-behavior relationships that were stable across R-fMRI scans collected one year apart. Two stable expected benefit-RSFC relationships were observed: decreased expected benefit (increased risk-aversion was associated with 1 stronger positive functional connectivity between right inferior frontal gyrus (IFG and right insula, and 2 weaker negative functional connectivity between left nucleus accumbens and right parieto-occipital cortex. CONCLUSIONS/SIGNIFICANCE: Task-based activation in the IFG and insula has been associated with risk-aversion, while activation in the nucleus accumbens and parietal cortex has been associated with both

  17. Risky Cerebrovascular Anatomic Orientation: Implications for Brain Revascularization.

    Science.gov (United States)

    Nagm, Alhusain; Horiuchi, Tetsuyoshi; Yanagawa, Takao; Hongo, Kazuhiro

    2016-12-01

    This study documents a risky vascular anatomic orientation that might play an important role in the postoperative hemodynamics following anterior cerebral artery (ACA) revascularization. A 71-year-old woman presented with uncontrollable frequent right lower limb transient ischemic attacks (TIAs) attributed to a left cerebral ischemic lesion due to severe left ACA stenosis. She underwent successful left-sided superficial temporal artery-ACA bypass using interposed vascular graft. The patient awoke satisfactory from anesthesia; however, on postoperative day 1, she developed right-sided hemiparesis. Extensive postoperative investigations disclosed that watershed shift infarction was considered the etiology for this neurologic deterioration.

  18. Deflection by kinetic impact: Sensitivity to asteroid properties

    Science.gov (United States)

    Bruck Syal, Megan; Michael Owen, J.; Miller, Paul L.

    2016-05-01

    Impacting an asteroid with a spacecraft traveling at high speed delivers an impulsive change in velocity to the body. In certain circumstances, this strategy could be used to deflect a hazardous asteroid, moving its orbital path off of an Earth-impacting course. However, the efficacy of momentum delivery to asteroids by hypervelocity impact is sensitive to both the impact conditions (particularly velocity) and specific characteristics of the target asteroid. Here we numerically model asteroid response to kinetic impactors under a wide range of initial conditions, using an Adaptive Smoothed Particle Hydrodynamics code. Impact velocities spanning 1-30 km/s were investigated, yielding, for a particular set of assumptions about the modeled target material, a power-law dependence consistent with a velocity-scaling exponent of μ = 0.44. Target characteristics including equation of state, strength model, porosity, rotational state, and shape were varied, and corresponding changes in asteroid response were documented. The kinetic-impact momentum-multiplication factor, β, decreases with increasing asteroid cohesion and increasing porosity. Although increased porosity lowers β, larger porosities result in greater deflection velocities, as a consequence of reduced target masses for asteroids of fixed size. Porosity also lowers disruption risk for kinetic impacts near the threshold of disruption. Including fast (P = 2.5 h) and very fast (P = 100 s) rotation did not significantly alter β but did affect the risk of disruption by the impact event. Asteroid shape is found to influence the efficiency of momentum delivery, as local slope conditions can change the orientation of the crater ejecta momentum vector. These results emphasize the need for asteroid characterization studies to bracket the range of target conditions expected at near-Earth asteroids while also highlighting some of the principal uncertainties associated with the kinetic-impact deflection strategy.

  19. BAOBAB (Big And Outrageously Bold Asteroid Belt) Project

    Science.gov (United States)

    Mcfadden, L. A.; Thomas, C. A; Englander, J. A.; Ruesch, O.; Hosseini, S.; Goossens, S. J.; Mazarico, E. M.; Schmerr, N.

    2017-01-01

    One of the intriguing results of NASA's Dawn mission is the composition and structure of the Main Asteroid Belt's only known dwarf planet, Ceres [1]. It has a top layer of dehydrated clays and salts [2] and an icy-rocky mantle [3,4]. It is widely known that the asteroid belt failed to accrete as a planet by resonances between the Sun and Jupiter. About 20-30 asteroids >100 km diameter are probably differentiated protoplanets [5]. 1) how many more and which ones are fragments of protoplanets? 2) How many and which ones are primordial rubble piles left over from condensation of the solar nebula? 3) How would we go about gaining better and more complete characterization of the mass, interior structure and composition of the Main Belt asteroid population? 4) What is the relationship between asteroids and ocean worlds? Bulk parameters such as the mass, density, and porosity, are important to characterize the structure of any celestial body, and for asteroids in particular, they can shed light on the conditions in the early solar system. Asteroid density estimates exist but currently they are often based on assumed properties of taxonomic classes, or through astronomical survey data where interactions with asteroids are weak at best resulting in large measurement uncertainty. We only have direct density estimates from spacecraft encounters for a few asteroids at this time. Knowledge of the asteroids is significant not only to understand their role in solar system workings, but also to assess their potential as space resources, as impact hazards on Earth, or even as harboring life forms. And for the distant future, we want to know if the idea put forth in a contest sponsored by Physics Today, to surface the asteroids into highly reflecting, polished surfaces and use them as a massively segmented mirror for astrophysical exploration [6], is feasible.

  20. Asteroid Redirect Crewed Mission Nominal Design and Performance

    Science.gov (United States)

    Condon, Gerald; williams, Jacob

    2014-01-01

    In 2010, the President announced that, in 2025, the U.S. intended to launch a human mission to an asteroid [1]. This announcement was followed by the idea of a Capability Driven Framework (CDF) [2], which is based on the idea of evolving capabilities from less demanding to more demanding missions to multiple possible destinations and with increased flexibility, cost effectiveness and sustainability. Focused missions, such as a NASA inter-Center study that examined the viability and implications of sending a crew to a Near Earth Asteroid (NEA) [3], provided a way to better understand and evaluate the utility of these CDF capabilities when applied to an actual mission. The long duration of the NEA missions were contrasted with a concept described in a study prepared for the Keck Institute of Space Studies (KISS) [4] where a robotic spacecraft would redirect an asteroid to the Earth-Moon vicinity, where a relatively short duration crewed mission could be conducted to the captured asteroid. This mission concept was included in the National Aeronautics and Space Administration (NASA) fiscal year 2014 budget request, as submitted by the NASA Administrator [5]. NASA studies continued to examine the idea of a crewed mission to a captured asteroid in the Earth-Moon vicinity. During this time was an announcement of NASA's Asteroid Grand Challenge [6]. Key goals for the Asteroid Grand Challenge are to locate, redirect, and explore an asteroid, as well as find and plan for asteroid threats. An Asteroid Redirect Mission (ARM) study was being conducted, which supports this Grand Challenge by providing understanding in how to execute an asteroid rendezvous, capture it, and redirect it to Earth-Moon space, and, in particular, to a distant retrograde orbit (DRO). Subsequent to the returning of the asteroid to a DRO, would be the launch of a crewed mission to rendezvous with the redirected asteroid. This report examines that crewed mission by assessing the Asteroid Redirect Crewed

  1. Albedo and Diameter Distributions of Asteroid Families Using the Spitzer Asteroid Catalog

    NARCIS (Netherlands)

    Enga, Marie-Therese; Trilling, D.; Mueller, M.; Wasserman, L.; Sykes, M.; Blaylock, M.; Stansberry, J.; Bhattacharya, B.; Spahr, T.

    2009-01-01

    The Spitzer Asteroid Catalog contains flux measurements of asteroidsserendipitously observed in publicly available Spitzer data. At present,this catalog contains some 10,000 measurements at 24 microns only, andwill ultimately contain 100,000 measurements or more. These measurements, along with with

  2. Albedo and Diameter Distributions of Asteroid Families Using the Spitzer Asteroid Catalog

    NARCIS (Netherlands)

    Enga, Marie-Therese; Trilling, D.; Mueller, M.; Wasserman, L.; Sykes, M.; Blaylock, M.; Stansberry, J.; Bhattacharya, B.; Spahr, T.

    2009-01-01

    The Spitzer Asteroid Catalog contains flux measurements of asteroidsserendipitously observed in publicly available Spitzer data. At present,this catalog contains some 10,000 measurements at 24 microns only, andwill ultimately contain 100,000 measurements or more. These measurements, along with with

  3. Photometry and models of selected main belt asteroids. IX. Introducing interactive service for asteroid models (ISAM)

    NARCIS (Netherlands)

    Marciniak, A.; Bartczak, P.; Santana-Ros, T.; Michalowski, T.; Antonini, P.; Behrend, R.; Bembrick, C.; Bernasconi, L.; Borczyk, W.; Colas, F.; Coloma, J.; Crippa, R.; Esseiva, N.; Fagas, M.; Fauvaud, M.; Fauvaud, S.; Ferreira, D. D. M.; Hein - Bertelsen, R.P.; Higgins, D.; Hirsch, R.; Kajava, J. J. E.; Kaminski, K.; Kryszczynska, A.; Kwiatkowski, T.; Manzini, F.; Michalowski, J.; Michalowski, M. J.; Paschke, A.; Polinska, M.; Poncy, R.; Roy, R.; Santacana, G.; Sobkowiak, K.; Stasik, M.; Starczewski, S.; Velichko, F.; Wucher, H.; Zafar, T.

    Context. The shapes and spin states of asteroids observed with photometric techniques can be reconstructed using the lightcurve inversion method. The resultant models can then be confirmed or exploited further by other techniques, such as adaptive optics, radar, thermal infrared, stellar

  4. Investigating the origin of the asteroids and early findings on Vesta historical studies in asteroid research

    CERN Document Server

    Cunningham, Clifford J

    2017-01-01

    This book assesses the origin of asteroids by analyzing the discovery of Vesta in 1807. Wilhelm Olbers, who discovered Vesta, suggested that the asteroids were the result of a primordial planet’s explosion. Cunningham studies that idea in detail through the writings of Sir David Brewster in Scotland, the era's most prolific writer about the asteroids. He also examines the link between meteorites and asteroids, revealing a synergy between Ernst Chladni, Romantic symbolism, and the music of the spheres. Vesta was a lightning rod for controversy throughout the nineteenth century with observers arguing over its size and color, and the astounding notion that it was self-luminous. It was also a major force for change, as new methods in the field of celestial mechanics were developed to study the orbital perturbations it is subject to. A large selection of private correspondence and scientific papers complete the first comprehensive historical study of Vesta ever published. With a synoptic look at the four astero...

  5. Using drama to target risky behaviours in Papua New Guinea.

    Science.gov (United States)

    Sommi, S S; Peter, W; Bisai, N

    2000-06-01

    This paper discusses the collaborative work between Papua New Guinea Institute of Medical Research, Lae, and the Seeds Performing Arts Theatre, which adopted the approach of using drama to target risky behaviors in the country. In a baseline study on knowledge, behavior and practice among target groups, results showed that general knowledge about sexually transmitted disease and HIV/AIDS is very poor in these groups. In addition, there is a continued practice of risky behaviors, which could lead to HIV infection among these groups. In view of such, drama presentations were undertaken to disseminate information to specific audiences. Scripts and songs were written and a flip chart was created to show the statistics on HIV/AIDS. In addition, role playing, which included references to factors facilitating the transmission of HIV was given. In 1998, a total of performances were given to over 3000 people: 12 for transport industry and sex workers, and 2 for general communities. Moreover, two other local theater groups were trained on HIV/AIDS topics.

  6. PERCEPTIONS OF BEER ADVERTISING AND RISKY DRINKING AMONG STUDENTS

    Directory of Open Access Journals (Sweden)

    Ślaski, Sławomir

    2014-09-01

    Full Text Available Aim. The main purpose of the research was to determine whether individuals at risk of drinking are people particularly susceptible to the effects of alcohol and viewing ads can be an incentive for re–consumption of alcohol. Material and method. The study group (40 persons were selected from 30 0 students, who used alcohol in a risky manner, and the control group (40 persons was selected, where alcohol was used with a little risk, or not at all. To assess the subjects selected product – beer (in the form of advertising leaflets, which was recently introduced into the Polish market. The Attitudes Questionnaire to view the Product was used in the study and contained scales: cognitive, emotional and behavioral component. To study perception of advertising the Advertising Scale was applied. To identify groups of people who use alcohol in a risky way, AUDIT Test was used. Results and conclusions. People at risk of drinking, liked beer more than those not at risk of addiction, and more often drink beer, have a more positive attitude towards the advertising of beer in emotional sphere, the above estimate of beer advertising in terms of potency, better evaluate the advertising of beer in terms of positive mood caused by it, and better evaluate beer advertising and its effectiveness in term of impact.

  7. Absolute magnitudes of asteroids and a revision of asteroid albedo estimates from WISE thermal observations

    Science.gov (United States)

    Pravec, Petr; Harris, Alan W.; Kušnirák, Peter; Galád, Adrián; Hornoch, Kamil

    2012-09-01

    We obtained estimates of the Johnson V absolute magnitudes (H) and slope parameters (G) for 583 main-belt and near-Earth asteroids observed at Ondřejov and Table Mountain Observatory from 1978 to 2011. Uncertainties of the absolute magnitudes in our sample are estimates reported by asteroid surveys. With our photometric H and G data, we revised the preliminary WISE albedo estimates made by Masiero et al. (Masired, J.R. et al. [2011]. Astrophys. J. 741, 68-89) and Mainzer et al. (Mainzer, A. et al. [2011b]. Astrophys. J. 743, 156-172) for asteroids in our sample. We found that the mean geometric albedo of Tholen/Bus/DeMeo C/G/B/F/P/D types with sizes of 25-300 km is pV = 0.057 with the standard deviation (dispersion) of the sample of 0.013 and the mean albedo of S/A/L types with sizes 0.6-200 km is 0.197 with the standard deviation of the sample of 0.051. The standard errors of the mean albedos are 0.002 and 0.006, respectively; systematic observational or modeling errors can predominate over the quoted formal errors. There is apparent only a small, marginally significant difference of 0.031 ± 0.011 between the mean albedos of sub-samples of large and small (divided at diameter 25 km) S/A/L asteroids, with the smaller ones having a higher albedo. The difference will have to be confirmed and explained; we speculate that it may be either a real size dependence of surface properties of S type asteroids or a small size-dependent bias in the data (e.g., a bias towards higher albedos in the optically-selected sample of asteroids). A trend of the mean of the preliminary WISE albedo estimates increasing with asteroid size decreasing from D ∼ 30 down to ∼5 km (for S types) showed in Mainzer et al. (Mainzer, A. et al. [2011a]. Astrophys. J. 741, 90-114) appears to be mainly due to the systematic bias in the MPCORB absolute magnitudes that progressively increases with H in the corresponding range H = 10-14.

  8. A Targeted Search for Trojan Asteroids in Kepler Lightcurves

    Science.gov (United States)

    Bordenave, David; Ballard, Sarah

    2015-01-01

    'Trojan' asteroids, or asteroids trapped in stable gravitational positions preceding and trailing a planet in its orbit, accompany almost every planet of our Solar System. They were captured into their current locations in the early stages of our solar system's formation, and their presence hints at the dynamical history of bodies orbiting the Sun. However, we have no reason to assume that our own planets are alone in possessing Trojan asteroids. NASA's Kepler mission, launched in 2009, has been instrumental in the recent search for exoplanets. It has identified thousands of new worlds to date. However, exo-Trojan asteroids have as-yet eluded detection. If asteroids are captured at both Lagrangian points, their folded transit signature is not strictly periodic (since transits occur 1/6th of the planetary period before and after transit), and may be missed by traditional search algorithms. Our targeted search, at the predicted times of transit, is best suited for identifying candidate Trojans. Moreover, we have focused our investigation upon the set of Kepler Objects of Interest (KOIs) that we predict will be most fruitful for Trojan detection. However, if we are unable to detect these Trojan asteroids, we will be able to set limiting constraints on the presence of asteroids in exoplanetary systems. Observations of these Trojan asteroids, or the lack thereof, would give insight to the evolution and migration models of these systems.

  9. Compositional differences between meteorites and near-Earth asteroids.

    Science.gov (United States)

    Vernazza, P; Binzel, R P; Thomas, C A; DeMeo, F E; Bus, S J; Rivkin, A S; Tokunaga, A T

    2008-08-14

    Understanding the nature and origin of the asteroid population in Earth's vicinity (near-Earth asteroids, and its subset of potentially hazardous asteroids) is a matter of both scientific interest and practical importance. It is generally expected that the compositions of the asteroids that are most likely to hit Earth should reflect those of the most common meteorites. Here we report that most near-Earth asteroids (including the potentially hazardous subset) have spectral properties quantitatively similar to the class of meteorites known as LL chondrites. The prominent Flora family in the inner part of the asteroid belt shares the same spectral properties, suggesting that it is a dominant source of near-Earth asteroids. The observed similarity of near-Earth asteroids to LL chondrites is, however, surprising, as this meteorite class is relatively rare ( approximately 8 per cent of all meteorite falls). One possible explanation is the role of a size-dependent process, such as the Yarkovsky effect, in transporting material from the main belt.

  10. Density and Macroporosity Distribution of Near Earth Asteroids

    Science.gov (United States)

    Dotson, Jessie L.; Mathias, Donovan

    2017-01-01

    The density of near earth asteroids is a fundamental property which can illuminate the structure of the asteroid, provide clues about it’s collisional history and is key in assessing the hazard of an impact of an NEA with Earth. A low density can be indicative of a rubble pile structure whereas a higher density can imply a monolith and/or a higher metal content. Unfortunately, measuring the density of asteroids is extremely difficult, has only been attempted for a tiny fraction of NEAs and usually results in measurements with large uncertainties. In the absence of density measurements for a specific object, understanding the range and distribution of likely densities can allow for probabilistic assessments of the population and facilitate estimates of the range of reasonable masses for a specific object. We have developed a candidate macroporosity distribution for near earth asteroids based on measurements of meteorite densities and asteroid densities. The macroporosity of an asteroid can be used to aid extrapolation from meteorite physical properties to asteroid physical properties. In addition, we discuss estimating an asteroid density distribution from the macroporosity distribution.

  11. Independent sets in asteroidal triple-free graphs

    NARCIS (Netherlands)

    Broersma, Haitze J.; Kloks, Ton; Kloks, A.J.J.; Kratsch, Dieter; Müller, Haiko

    1997-01-01

    An asteroidal triple is a set of three vertices such that there is a path between any pair of them avoiding the closed neighborhood of the third. A graph is called AT-free if it does not have an asteroidal triple. We show that there is an O(n 2 · (¯m+1)) time algorithm to compute the maximum

  12. Taxonomic Classification of Asteroids via Broadband Near-Infrared Photometry

    NARCIS (Netherlands)

    Petersen, Eric; Thomas, C.; Trilling, D.; Emery, J.; Delbo, M.; Mueller, M.; Dave, R.

    2010-01-01

    For faint asteroids, it is not practical to obtain near-infrared spectra. However, it may be possible to use broadband photometry to infer spectral classifications and study composition. As a test of this, we processed SpeX near-infrared asteroid spectral data to simulate colors that would be obtain

  13. Modeling Asteroid Dynamics using AMUSE: First Test Cases

    NARCIS (Netherlands)

    Frantseva, Kateryna; Mueller, Michael; van der Tak, Floris; Helmich, Frank P.

    2015-01-01

    We are creating a dynamic model of the current asteroid population. The goal is to reproduce measured impact rates in the current Solar System, from which we'll derive delivery rates of water and organic material by tracing low-albedo C-class asteroids (using the measured albedo distribution from WI

  14. Physical Properties of Near-Earth Asteroid 2011 MD

    NARCIS (Netherlands)

    Mommert, M.; Farnocchia, D.; Hora, J. L.; Chesley, S. R.; Trilling, D. E.; Chodas, P. W.; Mueller, M.; Harris, A. W.; Smith, H. A.; Fazio, G. G.

    2014-01-01

    We report on observations of near-Earth asteroid 2011 MD with the Spitzer Space Telescope. We have spent 19.9 h of observing time with channel 2 (4.5 {\\mu}m) of the Infrared Array Camera and detected the target within the 2{\\sigma} positional uncertainty ellipse. Using an asteroid thermophysical mod

  15. Optimised low-thrust mission to the Atira asteroids

    Science.gov (United States)

    Di Carlo, Marilena; Romero Martin, Juan Manuel; Ortiz Gomez, Natalia; Vasile, Massimiliano

    2017-04-01

    Atira asteroids are recently-discovered celestial bodies characterised by orbits lying completely inside the heliocentric orbit of the Earth. The study of these objects is difficult due to the limitations of ground-based observations: objects can only be detected when the Sun is not in the field of view of the telescope. However, many asteroids are expected to exist in the inner region of the Solar System, many of which could pose a significant threat to our planet. In this paper, a small, low-cost, mission to visit the known Atira asteroids and to discover new Near Earth Asteroids (NEA) is proposed. The mission is realised using electric propulsion. The trajectory is optimised to maximise the number of visited asteroids of the Atira group using the minimum propellant consumption. During the tour of the Atira asteroids an opportunistic NEA discovery campaign is proposed to increase our knowledge of the asteroid population. The mission ends with a transfer to an orbit with perihelion equal to Venus's orbit radius. This orbit represents a vantage point to monitor and detect asteroids in the inner part of the Solar System and provide early warning in the case of a potential impact.

  16. Earth-approaching asteroids: Populations, origin, and compositional types

    Science.gov (United States)

    Shoemaker, E. M.; Helin, E. F.

    1978-01-01

    Origin, physical properties, and discovery history of smaller asteroids are reviewed. They appear to link the main belt objects, namely the comets and meteorites. Physical observations suggest that a wide variety of compositional types are represented among the near-earth asteroids; the apparent rarity of carbonaceous objects is stated.

  17. Modeling Asteroid Dynamics using AMUSE: First Test Cases

    NARCIS (Netherlands)

    Frantseva, Kateryna; Mueller, Michael; van der Tak, Floris; Helmich, Frank P.

    2015-01-01

    We are creating a dynamic model of the current asteroid population. The goal is to reproduce measured impact rates in the current Solar System, from which we'll derive delivery rates of water and organic material by tracing low-albedo C-class asteroids (using the measured albedo distribution from

  18. Physical Properties of Near-Earth Asteroid 2011 MD

    NARCIS (Netherlands)

    Mommert, M.; Farnocchia, D.; Hora, J. L.; Chesley, S. R.; Trilling, D. E.; Chodas, P. W.; Mueller, M.; Harris, A. W.; Smith, H. A.; Fazio, G. G.

    2014-01-01

    We report on observations of near-Earth asteroid 2011 MD with the Spitzer Space Telescope. We have spent 19.9 h of observing time with channel 2 (4.5 {\\mu}m) of the Infrared Array Camera and detected the target within the 2{\\sigma} positional uncertainty ellipse. Using an asteroid thermophysical

  19. Modeling Asteroid Dynamics using AMUSE: First Test Cases

    NARCIS (Netherlands)

    Frantseva, Kateryna; Mueller, Michael; van der Tak, Floris; Helmich, Frank P.

    2015-01-01

    We are creating a dynamic model of the current asteroid population. The goal is to reproduce measured impact rates in the current Solar System, from which we'll derive delivery rates of water and organic material by tracing low-albedo C-class asteroids (using the measured albedo distribution from WI

  20. Near Earth Asteroids: A Classification System According to Their Shapes

    Science.gov (United States)

    Acevedo, R. D.; Rocca, M.; Rabassa, J.; Ponce, J. F.; Stinco, S.

    2012-09-01

    A new way to classify Near Earth Asteroids (NEAs) according to their shapes is proposed. This classification is based on the asteroid roundness and sphericity in the same way that it is used in geological sciences to describe clasts in mechanical sedimentary rocks.

  1. Lightcurve Analysis of the Near-Earth Asteroid 6063 Jason

    Science.gov (United States)

    Warner, Brian D.; Aznar Macias, Amadeo; Benishek, Vladimir; Oey, Julian; Gross, Roger

    2017-10-01

    CCD photometric observations of the near-Earth asteroid 6063 Jason were made in 2017 June. A collaboration of five observers at widely-separated longitudes proved critical in finding a synodic period of 48.6 h, nearly commensurate with an Earth day, and confirming that the asteroid is most likely tumbling.

  2. Volcanic processes on early-forming asteroids.

    Science.gov (United States)

    Wilson, L.; Keil, K.

    2011-12-01

    A variety of meteorite groups represent samples of asteroids that formed while 26Al was still the dominant heat source in Solar System materials. These bodies differentiated to varying degrees beyond the temperature of FeNi-FeS melting, with sufficient silicate melting to allow metal core formation. The silicate melts segregated upward from the interiors to suffer various fates: intrusion at shallow levels, eruption onto the surface, or ejection into space in explosive eruptions in which the eruption speed exceeded the escape speed. These three styles of plutonic/volcanic activity were not mutually exclusive; their relative importance was a function of asteroid size and composition, with the major compositional factor being the total available volatile inventory. Much research has been concerned with whether silicate melts were extracted from the mantle during the period of mantle heating or while the mantle was cooling after reaching its peak temperature and degree of partial melting (a "magma ocean" stage). Traditionally, the relevant arguments have been based on the petrology and geochemistry of the meteorites sampling these bodies. Instead, we focus on the fluid dynamic aspects of eruption and intrusion processes and show how these impose additional limitations on various aspects of the igneous activity. For example, 40% melting of bodies the size of 4 Vesta (~250 km radius) and the Ureilite Parent Body (UPB, ~100 km radius) over the course of a 0.5 Ma heating period represent melt volume production rates of ~350 and 20 cubic meters per second, respectively, in each of what we demonstrate should have been ~4 volcanic provinces on each body. All differentiated asteroids must of necessity have had a surface layer ~10 km thick at sub-solidus temperatures controlled by conductive cooling. To erupt magma at the surface (or intrude magma at very shallow depth) through such a crust would have required the propagation of dikes within which the combination of dike width

  3. Why we need asteroid sample return mission?

    Science.gov (United States)

    Barucci, Maria Antonietta

    2016-07-01

    Small bodies retain evidence of the primordial solar nebula and the earliest solar system processes that shaped their evolution. They may also contain pre-solar material as well as complex organic molecules, which could have a major role to the development of life on Earth. For these reasons, asteroids and comets have been targets of interest for missions for over three decades. However, our knowledge of these bodies is still very limited, and each asteroid or comet visited by space mission has revealed unexpected scientific results, e.g. the structure and nature of comet 67P/Churyumov-Gerasimenko (67P/C-G) visited by the Rosetta mission. Only in the laboratory can instruments with the necessary precision and sensitivity be applied to individual components of the complex mixture of materials that forms a small body regolith, to determine their precise chemical and isotopic composition. Such measurements are vital for revealing the evidence of stellar, interstellar medium, pre-solar nebula and parent body processes that are retained in primitive material, unaltered by atmospheric entry or terrestrial contamination. For those reasons, sample return missions are considered a high priority by a number of the leading space agencies. Abundant within the inner Solar System and the main impactors on terrestrial planets, small bodies may have been the principal contributors of the water and organic material essential to create life on Earth. Small bodies can therefore be considered to be equivalent to DNA for unravelling our solar system's history, offering us a unique window to investigate both the formation of planets and the origin of life. A sample return mission to a primitive Near-Earth Asteroid (NEA) has been study at ESA from 2008 in the framework of ESA's Cosmic Vision (CV) programme, with the objective to answer to the fundamental CV questions "How does the Solar System work?" and "What are the conditions for life and planetary formations?". The returned material

  4. Business modelling agility: Turning ideas into business

    NARCIS (Netherlands)

    Heikkila, J.; Heikkila, M.; Bouwman, W.A.G.A.

    2015-01-01

    Business Model Innovation is attracting more and more attention from business as well as from academics. Business Model Innovation deals with both technological and knowledge related changes that either may disrupt or sustain existing product/market strategies. Timing of Business Model Innovation

  5. Business modelling agility: Turning ideas into business

    NARCIS (Netherlands)

    Heikkila, J.; Heikkila, M.; Bouwman, W.A.G.A.

    2015-01-01

    Business Model Innovation is attracting more and more attention from business as well as from academics. Business Model Innovation deals with both technological and knowledge related changes that either may disrupt or sustain existing product/market strategies. Timing of Business Model Innovation bo

  6. A business case method for business models

    NARCIS (Netherlands)

    Meertens, Lucas Onno; Starreveld, E.; Iacob, Maria Eugenia; Nieuwenhuis, Lambertus Johannes Maria; Shishkov, Boris

    2013-01-01

    Intuitively, business cases and business models are closely connected. However, a thorough literature review revealed no research on the combination of them. Besides that, little is written on the evaluation of business models at all. This makes it difficult to compare different business model

  7. The Micro-mechanics of Asteroid Dust

    Science.gov (United States)

    Sanchez Lana, Diego Paul; Scheeres, Daniel J.

    2016-10-01

    Current understanding is that small asteroids in the Solar System are gravitational aggregates that are held together by gravitational, cohesive and adhesive forces. Though the mechanics of how gravitational forces work is very well understood, the same cannot be said about the other two.In our earlier research we used a Discrete-Element-Method simulation code to calculate the tensile strength of an assemblage of cohesive particles and found that the main geometrical factor controlling bulk strength was the average size of the particles (Sanchez and Scheeres 2014, MAPS). Specifically, the smaller the average size, the greater the tensile strength as r^-1, as though the magnitude of the van der Waals force applied decrease with the radius of the grains (r), the number of contacts per unit area increases with r^-2. This dependency has been corroborated by some observational evidence of the global strength of granular asteroids; however, our simulations were carried out with spherical particles and therefore in these simulations it is impossible to consider more than one contact per pair of particles. Other parameters such as different chemical composition and wider size distribution of the grains, changes in porosity and number of contacts per particle (coordination number) were not taken into direct account either. The study of each one of these parameters is of interest, and our research has started to explore the effect of these on the net cohesive force found in an asteroid's regolith and interior.Our initial study will simulate the effect of a wider size distribution in the granular material, comparing this with theoretical predictions. This parameter can cause a change in porosity and coordination number of the grains. This will have a measurable effect in the tensile strength of the aggregate and will provide a first look into the strength of a more realistic cohesive granular media. The results of this research will be shown at the conference.

  8. New active asteroid 313P/Gibbs

    Energy Technology Data Exchange (ETDEWEB)

    Jewitt, David; Hui, Man-To; Li, Jing [Department of Earth, Planetary and Space Sciences, UCLA, 595 Charles Young Drive East, Los Angeles, CA 90095-1567 (United States); Agarwal, Jessica [Max Planck Institute for Solar System Research, Max-Planck-Str. 2, D-37191 Katlenburg-Lindau (Germany); Peixinho, Nuno [Unidad de Astronomía, Fac. de Ciencias Básicas, Universidad de Antofagasta, Avda. U. de Antofagasta 02800, Antofagasta (Chile); Weaver, Harold [The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, Maryland, MD 20723 (United States); Mutchler, Max [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Larson, Stephen, E-mail: jewitt@ucla.edu [Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Blvd. Tucson AZ 85721-0092 (United States)

    2015-02-01

    We present initial observations of the newly discovered active asteroid 313P/Gibbs (formerly P/2014 S4), taken to characterize its nucleus and comet-like activity. The central object has a radius ∼0.5 km (geometric albedo 0.05 assumed). We find no evidence for secondary nuclei and set (with qualifications) an upper limit to the radii of such objects near 20 m, assuming the same albedo. Both aperture photometry and a morphological analysis of the ejected dust show that mass-loss is continuous at rates ∼0.2–0.4 kg s{sup −1}, inconsistent with an impact origin. Large dust particles, with radii ∼50–100 μm, dominate the optical appearance. At 2.4 AU from the Sun, the surface equilibrium temperatures are too low for thermal or desiccation stresses to be responsible for the ejection of dust. No gas is spectroscopically detected (limiting the gas mass-loss rate to <1.8 kg s{sup −1}). However, the protracted emission of dust seen in our data and the detection of another episode of dust release near perihelion, in archival observations from 2003, are highly suggestive of an origin by the sublimation of ice. Coincidentally, the orbit of 313P/Gibbs is similar to those of several active asteroids independently suspected to be ice sublimators, including P/2012 T1, 238P/Read, and 133P/Elst–Pizarro, suggesting that ice is abundant in the outer asteroid belt.

  9. Categorising Risky Play--How Can We Identify Risk-Taking in Children's Play?

    Science.gov (United States)

    Sandseter, Ellen Beate Hansen

    2007-01-01

    There is a growing debate on the balance between making sure our children are safe versus letting the children play in physically and emotionally stimulating and challenging environments. The focus is now on children's right to do risky play. There are no studies categorising risky play. The present study has aimed to do this. Qualitative…

  10. Child Abuse, Early Maladaptive Schemas, and Risky Sexual Behavior in College Women

    Science.gov (United States)

    Roemmele, Melissa; Messman-Moore, Terri L.

    2011-01-01

    Previous research suggests that individuals abused as children are more likely to engage in risky sexual behavior during adulthood. The present study examined early maladaptive schemas as mediators of the child abuse-risky sexual behavior relationship among 653 college women. Self-report surveys assessed three forms of child abuse: Sexual,…

  11. Genetic and environmental influences on risky sexual behaviour and its relationship with personality

    NARCIS (Netherlands)

    Zietsch, B.P.; Verweij, K.J.H.; Bailey, J.M.; Wright, M.J.; Martin, N.G.

    2010-01-01

    Risky sexual behaviour is a major health issue in society, and it is therefore important to understand factors that may predispose individuals to such behaviour. Research suggests a link between risky sexual behaviour and personality, but the basis of this link remains unknown. Hans Eysenck proposed

  12. The Evolutionary Basis of Risky Adolescent Behavior: Implications for Science, Policy, and Practice

    Science.gov (United States)

    Ellis, Bruce J.; Del Giudice, Marco; Dishion, Thomas J.; Figueredo, Aurelio Jose; Gray, Peter; Griskevicius, Vladas; Hawley, Patricia H.; Jacobs, W. Jake; James, Jenee; Volk, Anthony A.; Wilson, David Sloan

    2012-01-01

    This article proposes an evolutionary model of risky behavior in adolescence and contrasts it with the prevailing developmental psychopathology model. The evolutionary model contends that understanding the evolutionary functions of adolescence is critical to explaining why adolescents engage in risky behavior and that successful intervention…

  13. Child Abuse, Early Maladaptive Schemas, and Risky Sexual Behavior in College Women

    Science.gov (United States)

    Roemmele, Melissa; Messman-Moore, Terri L.

    2011-01-01

    Previous research suggests that individuals abused as children are more likely to engage in risky sexual behavior during adulthood. The present study examined early maladaptive schemas as mediators of the child abuse-risky sexual behavior relationship among 653 college women. Self-report surveys assessed three forms of child abuse: Sexual,…

  14. From Racial Discrimination to Risky Sex: Prospective Relations Involving Peers and Parents

    Science.gov (United States)

    Roberts, Megan E.; Gibbons, Frederick X.; Gerrard, Meg; Weng, Chih-Yuan; Murry, Velma M.; Simons, Leslie G.; Simons, Ronald L.; Lorenz, Frederick O.

    2012-01-01

    This study investigated how early experience with racial discrimination affected the subsequent risky sexual behaviors of a diverse sample of African American youths (N = 745). The analyses focused on 3 risk-promoting factors thought to mediate the hypothesized discrimination--risky sex relation: negative affect, affiliation with deviant peers,…

  15. The Role of Religiosity in the Relationship between Parents, Peers, and Adolescent Risky Sexual Behavior

    Science.gov (United States)

    Landor, Antoinette; Simons, Leslie Gordon; Simons, Ronald L.; Brody, Gene H.; Gibbons, Frederick X.

    2011-01-01

    Research has documented a negative relationship between religion and risky sexual behavior. Few studies, however, have examined the processes whereby religion exerts this effect. The present study develops and tests a model of various mechanisms whereby parental religiosity reduces the likelihood of adolescents' participation in risky sexual…

  16. The Evolutionary Basis of Risky Adolescent Behavior: Implications for Science, Policy, and Practice

    Science.gov (United States)

    Ellis, Bruce J.; Del Giudice, Marco; Dishion, Thomas J.; Figueredo, Aurelio Jose; Gray, Peter; Griskevicius, Vladas; Hawley, Patricia H.; Jacobs, W. Jake; James, Jenee; Volk, Anthony A.; Wilson, David Sloan

    2012-01-01

    This article proposes an evolutionary model of risky behavior in adolescence and contrasts it with the prevailing developmental psychopathology model. The evolutionary model contends that understanding the evolutionary functions of adolescence is critical to explaining why adolescents engage in risky behavior and that successful intervention…

  17. Identifying Mediators of the Influence of Family Factors on Risky Sexual Behavior

    Science.gov (United States)

    Simons, Leslie Gordon; Burt, Callie Harbin; Tambling, Rachel Blyskal

    2013-01-01

    Participation in risky sexual behaviors has many deleterious consequences and is a source of concern for parents as well as practitioners, researchers, and public policy makers. Past research has examined the effect of family structure and supportive parenting on risky sexual behaviors among emerging adults. In the present study, we attempt to…

  18. Peer Rejection, Affiliation with Deviant Peers, Delinquency, and Risky Sexual Behavior

    Science.gov (United States)

    Lansford, Jennifer E.; Dodge, Kenneth A.; Fontaine, Reid Griffith; Bates, John E.; Pettit, Gregory S.

    2014-01-01

    Risky sexual behavior poses significant health risks by increasing sexually transmitted infections and unintended pregnancies. Previous research has documented many factors related to risky sexual behavior. This study adds to the literature by proposing a prospective, developmental model of peer factors related to risky sexual behavior. Developmental pathways to risky sexual behavior were examined in a sample of 517 individuals (51% female; 82% European American, 16% African American, 2% other) followed from age 5 to 27. Structural equation models examined direct and indirect effects of peer rejection (assessed via peer nominations at ages 5, 6, 7, and 8), affiliation with deviant peers (assessed via self-report at ages 11 and 12), and delinquency (assessed via maternal report at ages 10 and 16) on risky sexual behavior (assessed via self-report at age 27). More peer rejection during childhood, affiliation with deviant peers during pre- adolescence, and delinquency in childhood and adolescence predicted more risky sexual behavior through age 27, although delinquency at age 16 was the only risk factor that had a significant direct effect on risky sexual behavior through age 27 above and beyond the other risk factors. Peer rejection was related to subsequent risk factors for girls but not boys. Peer risk factors as early as age 5 shape developmental pathways through childhood and adolescence and have implications for risky sexual behavior into adulthood. PMID:25150986

  19. Period Determination of Six Main Belt Asteroids

    Science.gov (United States)

    Ferrero, Andrea

    2014-07-01

    Observations of six main-belt asteroids (MBA) produced lightcurve parameters of: 487 Venetia, P = 13.34 ± 0.01 h, A = 0.20 mag; 684 Hildburg, P = 15.89 ± 0.01 h, A = 0.22 mag; 772 Tanete, P = 8.629 ± 0.001 h, A = 0.18 mag.; 1181 Lilith, P = 15.04 ± 0.01 h, A = 0.11 mag.; 1246 Chaka, P = 25.44 ± 0.01 h, A = 0.25 mag.; and 2834 Christy Carol, P = 12.79 ± 0.01 h, A = 0.39 mag.

  20. NASA's Near Earth Asteroid Scout Mission

    Science.gov (United States)

    Johnson, Les; McNutt, Leslie; Castillo-Rogez, Julie

    2017-01-01

    NASA is developing solar sail propulsion for a near-term Near Earth Asteroid (NEA) reconnaissance mission and laying the groundwork for their future use in deep space science and exploration missions. The NEA Scout mission, funded by NASA's Advanced Exploration Systems Program and managed by NASA MSFC, will use the sail as primary propulsion allowing it to survey and image one or more NEA's of interest for possible future human exploration. NEA Scout uses a 6U cubesat (to be provided by NASA's Jet Propulsion Laboratory), an 86 m2 solar sail and will weigh less than 14 kilograms. The solar sail for NEA Scout will be based on the technology developed and flown by the NASA NanoSail-D and The Planetary Society's Lightsail-A. Four 7 m stainless steel booms wrapped on two spools (two overlapping booms per spool) will be motor deployed and pull the sail from its stowed volume. The sail material is an aluminized polyimide approximately 3 microns thick. NEA Scout will launch on the Space Launch System (SLS) first mission in 2018 and deploy from the SLS after the Orion spacecraft is separated from the SLS upper stage. The NEA Scout spacecraft will stabilize its orientation after ejection using an onboard cold-gas thruster system. The same system provides the vehicle Delta-V sufficient for a lunar flyby. After its first encounter with the moon, the 86 m2 sail will deploy, and the sail characterization phase will begin. A mechanical Active Mass Translation (AMT) system, combined with the remaining ACS propellant, will be used for sail momentum management. Once the system is checked out, the spacecraft will perform a series of lunar flybys until it achieves optimum departure trajectory to the target asteroid. The spacecraft will then begin its two year-long cruise. About one month before the asteroid flyby, NEA Scout will pause to search for the target and start its approach phase using a combination of radio tracking and optical navigation. The solar sail will provide

  1. Impulsive orbit control for spacecraft around asteroid

    Institute of Scientific and Technical Information of China (English)

    崔祜涛; 崔平远; 栾恩杰

    2003-01-01

    An impulse feedback control law to change the mean orbit elements of spacecraft around asteroid is presented. First, the mean orbit elements are transferred to the osculating orbit elements at the burning time.Then, the feedback control law based on Gauss' s perturbation equations of motion is given. And the impulse control for targeting from the higher circulation orbit to the specified periapsis is developed. Finally, the numerical simulation is performed and the simulation results show that the presented impulse control law is effective.

  2. Microspine Gripping Mechanism for Asteroid Capture

    Science.gov (United States)

    Merriam, Ezekiel G.; Berg, Andrew B.; Willig, Andrew; Parness, Aaron; Frey, Tim; Howell, Larry L.

    2016-01-01

    This paper details the development and early testing of a compliant suspension for a microspine gripper device for asteroid capture or micro-gravity percussive drilling. The microspine gripper architecture is reviewed, and a proposed microspine suspension design is presented and discussed. Prototyping methods are discussed, as well as testing methods and results. A path forward is identified from the results of the testing completed thus far. Key findings include: the microspine concept has been established as a valid architecture and the compliant suspension exhibits the desired stiffness characteristics for good gripping behavior. These developments will aid in developing the capability to grasp irregularly shaped boulders in micro-gravity.

  3. The Nearest of the Near Earth Asteroids

    Science.gov (United States)

    Kortenkamp, Stephen J.

    2014-11-01

    While the orbits of many known near-Earth objects (NEOs) may cross that of Earth, very few NEOs actually approach near to Earth itself. In fact, the majority of NEOs spend most of their orbital periods in the asteroid belt beyond Mars. However, there is a subset of NEOs on orbits which allow for repeated close-encounters with Earth. These objects are locked in a co-orbital resonance with Earth, orbiting the sun in exactly one year. This unusual one-to-one resonance causes the NEOs to appear to be orbiting Earth and gives them their name; quasi-satellites.Despite their close proximity to Earth, only recently have the first quasi-satellites of Earth been detected. These are the asteroids 2003 YN107, 2004 GU9, and 2006 FV35. We carried out N-body computer simulations of these asteroids as well as a larger theoretical population. We demonstrate that quasi-satellite asteroids always remain exceptionally close to Earth, typically just 20-60 times farther than the moon, and undergo two close-encounters with Earth each year. Furthermore, quasi-satellites that eventually escape the resonance can have extremely deep low-velocity close-encounters with Earth as they leave the resonance, some coming well inside the orbit of the moon.When weak drag forces are included in the simulations quasi-satellite objects evolve onto more Earth-like orbits and spiral closer and closer to Earth. This dramatically reduces the relative velocity and distance of closest approach between Earth and the quasi-satellite object. Under the influence of weak drag quasi-satellites objects can develop effective encounter velocities of just a few hundred meters per second, often much less. These low encounter velocities lead to a strong enhancement in Earth’s gravitationally enhanced impact cross-section compared to close-encounters of non-resonant objects with similar initial orbital elements.This research is supported by NASA grant NNX14AN23G.

  4. Space Weathering Trends Among Carbonaceous Asteroids

    CERN Document Server

    Kaluna, Heather M; Meech, Karen J

    2015-01-01

    We present visible spectroscopic and albedo data of the 2.3 Gyr old Themis family and the 15 km) and small (< 15 km) Themis members suggest these phyllosilicate feature and albedo trends result from regolith variations as a function of diameter. Observations of the Beagle asteroids show a small, but notable fraction of members with phyllosilicate features. The presence of phyllosilicates and the dynamical association of the main-belt comet 133P/Elst-Pizarro with the Beagle family imply the Beagle parent body was a heterogenous mixture of ice and aqueously altered minerals.

  5. Two new basaltic asteroids in the Outer Main Belt

    CERN Document Server

    Duffard, R

    2007-01-01

    The identification of other basaltic objects in the asteroid belt is mandatory to explain the diversity in the collection of basaltic meteorites. This diversity requires more than one differentiated parent body, a fact that is consistent with the diversity of differentiated parent bodies implied by the iron meteorites. Based on a list of previously identified candidate basaltic (V-type) asteroids, two asteroids in the outer main belt, (7472) Kumakiri and (10537) 1991 RY16, were spectroscopically observed during an observational run in Calar Alto Observatory, Spain. We confirm the V-type character of these two asteroids that, together with (1459) Magnya, become the only known traces of basaltic found in the outer main belt up to now. We also demonstrate that the searching for candidate V-type asteroids using a photometric survey, like the Sloan Digital Sky Survey, produces reliable results.

  6. Asteroid fission, binaries and the small main belt population

    Science.gov (United States)

    Rossi, A.; Jacobson, S.; Marzari, F.; Scheeres, D.

    2011-10-01

    Using a Monte Carlo method we model the spin evolution of small Main Belt asteroids under the joint effects of YORP and collisions. Our simulations allow us to estimate the fraction of asteroids undergoing rotational fission in different size ranges. When an asteroid reaches its disruption spin limit we determine the outcome of its subsequent evolution based on accumulated statistics on their evolution based on numerical integrations (i.e., binary or ternary formation, binary disruption, etc..). Our aim is to predict the percentage of binary asteroids and their properties in the Belt, the number of objects like P/2010 A2 per year and the effects of YORP-induced fission on the overall asteroid size distribution at the small size end.

  7. Mining the CFHT Legacy Survey for known Near Earth Asteroids

    CERN Document Server

    Vaduvescu, O; Birlan, M; Toma, R; Badea, M; Dumitru, D; Opriseanu, C; Vidican, D; 10.1002/asna.201011550

    2011-01-01

    The Canada-France-Hawaii Legacy Survey (CFHTLS) comprising about 25 000 MegaCam images was data mined to search for serendipitous encounters of known Near Earth Asteroids (NEAs) and Potentially Hazardous Asteroids (PHAs). A total of 143 asteroids (109 NEAs and 34 PHAs) were found on 508 candidate images which were field corrected and measured carefully, and their astrometry was reported to Minor Planet Centre. Both recoveries and precoveries (apparitions before discovery) were reported, including data for 27 precovered asteroids (20 NEAs and 7 PHAs) and 116 recovered asteroids (89 NEAs and 27 PHAs). Our data prolonged arcs for 41 orbits at first or last opposition, refined 35 orbits by fitting data taken at one new opposition, recovered 6 NEAs at their second opposition and allowed us to ameliorate most orbits and their Minimal Orbital Intersection Distance (MOID), an important parameter to monitor for potential Earth impact hazard in the future.

  8. The Asteroid Catalog Using AKARI IRC Slow-Scan Observations

    CERN Document Server

    Hasegawa, Sunao; Kuroda, Daisuke; Takita, Satoshi; Usui, Fumihiko

    2012-01-01

    We present an asteroidal catalog from the mid-infrared wavelength region using the slow-scan observation mode obtained by the Infrared Camera (IRC) on-board the Japanese infrared satellite AKARI. An archive of IRC slow-scan observations comprising about 1000 images was used to search for serendipitous encounters of known asteroids. We have determined the geometric albedos and diameters for 88 main-belt asteroids, including two asteroids in the Hilda region, and compared these, where possible, with previously published values. Approximately one-third of the acquired data reflects new asteroidal information. Some bodies classified as C or D-type with high albedo were also identified in the catalog.

  9. Jovian Early Bombardment: planetesimal erosion in the inner asteroid belt

    CERN Document Server

    Turrini, Diego; Magni, Gianfranco

    2012-01-01

    The asteroid belt is an open window on the history of the Solar System, as it preserves records of both its formation process and its secular evolution. The progenitors of the present-day asteroids formed in the Solar Nebula almost contemporary to the giant planets. The actual process producing the first generation of asteroids is uncertain, strongly depending on the physical characteristics of the Solar Nebula, and the different scenarios produce very diverse initial size-frequency distributions. In this work we investigate the implications of the formation of Jupiter, plausibly the first giant planet to form, on the evolution of the primordial asteroid belt. The formation of Jupiter triggered a short but intense period of primordial bombardment, previously unaccounted for, which caused an early phase of enhanced collisional evolution in the asteroid belt. Our results indicate that this Jovian Early Bombardment caused the erosion or the disruption of bodies smaller than a threshold size, which strongly depen...

  10. An automatic approach to exclude interlopers from asteroid families

    Science.gov (United States)

    Radović, Viktor; Novaković, Bojan; Carruba, Valerio; Marčeta, Dušan

    2017-09-01

    Asteroid families are a valuable source of information to many asteroid-related researches, assuming a reliable list of their members could be obtained. However, as the number of known asteroids increases fast it becomes more and more difficult to obtain a robust list of members of an asteroid family. Here, we are proposing a new approach to deal with the problem, based on the well-known hierarchical clustering method. An additional step in the whole procedure is introduced in order to reduce a so-called chaining effect. The main idea is to prevent chaining through an already identified interloper. We show that in this way a number of potential interlopers among family members is significantly reduced. Moreover, we developed an automatic online-based portal to apply this procedure, i.e. to generate a list of family members as well as a list of potential interlopers. The Asteroid Families Portal is freely available to all interested researchers.

  11. 5m Main Belt Asteroid Population Estimation Using Vesta Imagery

    Science.gov (United States)

    Rynders, Michael; Trilling, David E.

    2016-10-01

    The Main Belt is the largest source of Near-Earth asteroids, but objects 2 pixels in diameter that were counted in a 33km 2 region to give a crater density. By knowing the crater density and making some reasonable assumptions about the orbital distribution of asteroids and the age of Vesta's surface, an estimate of the population of small asteroids in the inner main belt was made. It was found that the inner region of the main asteroid belt contains approximately 20 billion asteroids larger than 5 m. These results agree well with the measured inner Main Belt Size distribution derived by the Wide-field Infrared Survey Explorer, WISE (Masiero et al. 2011).

  12. Asteroid spin-axis longitudes from the Lowell Observatory database

    CERN Document Server

    Bowell, E; Wasserman, L H; Muinonen, K; Penttilä, A; Trilling, D E

    2013-01-01

    By analyzing brightness variation with ecliptic longitude and using the Lowell Observatory photometric database, we estimate spin-axis longitudes for more than 350 000 asteroids. Hitherto, spin-axis longitude estimates have been made for fewer than 200 asteroids. We investigate longitude distributions in different dynamical groups and asteroid families. We show that asteroid spin-axis longitudes are not isotropically distributed as previously considered. We find that the spin-axis longitude distribution for main-belt asteroids is clearly non-random, with an excess of longitudes from the interval 30{\\deg}-110{\\deg} and a paucity between 120{\\deg}-180{\\deg}. The explanation of the non-isotropic distribution is unknown at this point. Further studies have to be conducted to determine if the shape of the distribution can be explained by observational bias, selection effects, a real physical process or other mechanism.

  13. Visual and near-IR spectrophotometry of asteroids

    Science.gov (United States)

    Lebofsky, Larry A.

    1991-01-01

    We have been continuing our studies of the spectral properties of dark asteroids in the solar system. From these studies we expect to learn about the distribution of volatile materials, such as water in clay materials (water of hydration) and how the asteroids may relate to the comets. Our most recent work has been concentrating on simultaneous visual and near infrared photometry near Earth, main belt, and trojan asteroids. We have made observations of some unusual asteroids such as Chiron, which has recently shown cometary activity, and 944 Hidalgo, which has a comet-like orbit. We have also begun studies of the small, dark satellites of Mars and Jupiter in order to understand better how they may relate to the steroids. Could they actually be captured asteroids or comets?

  14. Landslides and Mass Shedding on Spinning Spheroidal Asteroids

    CERN Document Server

    Scheeres, D J

    2014-01-01

    Conditions for regolith landslides to occur on spinning, gravitating spheroidal asteroids and their aftermath are studied. These conditions are developed by application of classical granular mechanics stability analysis to the asteroid environment. As part of our study we determine how slopes evolve across the surface of these bodies as a function of spin rate, the dynamical fate of material that exceeds the angle of repose, and an analysis of how the shape of the body may be modified based on these results. We find specific characteristics for body surfaces and shapes when spun near the surface disruption limit and develop what their observable implications are. The small, oblate and rapidly spinning asteroids such as 1999 KW4 Alpha and 2008 EV5 exhibit some of these observable traits. The detailed mechanisms outlined here can also provide insight and constraints on the recently observed active asteroids such as P/2013 P5, and the creation of asteroidal meteor streams.

  15. Scaling forces to asteroid surfaces: The role of cohesion

    CERN Document Server

    Scheeres, D J; Sanchez, P; Swift, M

    2010-01-01

    The scaling of physical forces to the extremely low ambient gravitational acceleration regimes found on the surfaces of small asteroids is performed. Resulting from this, it is found that van der Waals cohesive forces between regolith grains on asteroid surfaces should be a dominant force and compete with particle weights and be greater, in general, than electrostatic and solar radiation pressure forces. Based on this scaling, we interpret previous experiments performed on cohesive powders in the terrestrial environment as being relevant for the understanding of processes on asteroid surfaces. The implications of these terrestrial experiments for interpreting observations of asteroid surfaces and macro-porosity are considered, and yield interpretations that differ from previously assumed processes for these environments. Based on this understanding, we propose a new model for the end state of small, rapidly rotating asteroids which allows them to be comprised of relatively fine regolith grains held together b...

  16. A comparison of family interventions to address adolescent risky behaviors: a literature review.

    Science.gov (United States)

    Kao, Tsui-Sui; Gibbs, Marilyn Beth; Clemen-Stone, Susan; Duffy, Sonia

    2013-05-01

    The purpose of this integrative review is to describe, compare, and synthesize traditional and computer-based family interventions that aim to change adolescents' risky sexual behaviors and substance abuse. Family interventions have been shown to generate protective effects for preventing adolescents from risky behaviors. It is not clear, however, whether there are significant differences or similarities in the designs and effects of traditional and computer-based family interventions. An integrative literature review was conducted to describe and compare the designs and effects of traditional and computer-based family interventions. Both interventions have generated significant effects on reducing risky behavior among adolescents. Interventions guided by theory, tailored to participants' culture/gender, and which included sufficient boosting dosages in their designs demonstrated significant short- or long-term effects in terms of reducing adolescents' risky behaviors. Regardless of delivery method, well-designed family interventions are noted to maximize familial protective effects and reduce risky behaviors.

  17. Business Model Innovation

    OpenAIRE

    Dodgson, Mark; Gann, David; Phillips, Nelson; Massa, Lorenzo; Tucci, Christopher

    2014-01-01

    The chapter offers a broad review of the literature at the nexus between Business Models and innovation studies, and examines the notion of Business Model Innovation in three different situations: Business Model Design in newly formed organizations, Business Model Reconfiguration in incumbent firms, and Business Model Innovation in the broad context of sustainability. Tools and perspectives to make sense of Business Models and support managers and entrepreneurs in dealing with Business Model ...

  18. [Socioeconomic status and risky health behaviors in Croatian adult population].

    Science.gov (United States)

    Pilić, Leta; Dzakula, Aleksandar

    2013-03-01

    Based on the previous research, there is strong association between low socioeconomic status (SES) and high morbidity and mortality rates. Even though association between SES and risky health behaviors as the main factors influencing health has been investigated in Croatian population, some questions are yet to be answered. The aim of this study was to investigate the presence of unhealthy diet, physical inactivity, smoking and excessive drinking in low, middle, and high socioeconomic group of adult Croatian population included in the cohort study on regionalism of cardiovascular health risk behaviors. We also investigated the association between SES measured by income, education and occupation, as well as single SES indicators, and risky health behaviors. We analyzed data on 1227 adult men and women (aged 19 and older at baseline) with complete data on health behaviors, SES and chronic diseases at baseline (2003) and 5-year follow up. Respondents were classified as being healthy or chronically ill. SES categories were derived from answers to questions on monthly household income, occupation and education by using two-step cluster analysis algorithm. At baseline, for the whole sample as well as for healthy respondents, SES was statistically significantly associated with unhealthy diet (whole sample/healthy respondents: p = 0.001), physical inactivity (whole sample/healthy respondents p = 0.44/ p = 0.007), and smoking (whole sample/healthy respondents p < 0.001/p = 0.002). The proportion of respondents with unhealthy diet was greatest in the lowest social class, smokers in the middle and physically inactive in the high social class. During the follow up, smoking and physical inactivity remained statistically significantly associated with SES. In chronically ill respondents, only smoking was statistically significantly associated with SES, at baseline and follow up (p = 0.001/p = 0.002). The highest share of smokers was in the middle social class. Results of our

  19. The Albedo Distribution of Near Earth Asteroids

    CERN Document Server

    Wright, Edward L; Masiero, Joseph; Grav, Tommy; Bauer, James

    2016-01-01

    The cryogenic WISE mission in 2010 was extremely sensitive to asteroids and not biased against detecting dark objects. The albedos of 428 Near Earth Asteroids (NEAs) observed by WISE during its fully cryogenic mission can be fit quite well by a 3 parameter function that is the sum of two Rayleigh distributions. The Rayleigh distribution is zero for negative values, and follows $f(x) = x \\exp[-x^2/(2\\sigma^2)]/\\sigma^2$ for positive x. The peak value is at x=\\sigma, so the position and width are tied together. The three parameters are the fraction of the objects in the dark population, the position of the dark peak, and the position of the brighter peak. We find that 25.3% of the NEAs observed by WISE are in a very dark population peaking at $p_V = 0.03$, while the other 74.7% of the NEAs seen by WISE are in a moderately dark population peaking at $p_V = 0.168$. A consequence of this bimodal distribution is that the Congressional mandate to find 90% of all NEAs larger than 140 m diameter cannot be satisfied by...

  20. Galileo photometry of asteroid 243 Ida

    Science.gov (United States)

    Helfenstein, P.; Veverka, J.; Thomas, P.C.; Simonelli, D.P.; Klaasen, K.; Johnson, T.V.; Fanale, F.; Granahan, J.; McEwen, A.S.; Belton, M.; Chapman, C.

    1996-01-01

    Galileo imaging observations over phase angles 19.5?? to 109.8?? are combined with near-opposition Earth-based data to derive the photometric properties of Ida. To first order these properties are uniform over the surface and well modeled at ?? = 0.55 ??m by Hapke parameters ????0 = 0.22, h = 0.020, B0 = 1.5, g = -0.33, and ?? = 18?? with corresponding geometric albedo p = 0.21??0.030.01 and Bond albedo AB = 0.081??0.0170.008. Ida's photometric properties are more similar to those of "average S-asteroids" (P. Helfenstein and J. Veverka 1989, Asteroids II, Univ. of Arizona Press, Tucson) than are those of 951 Gaspra. Two primary color units are identified on Ida: Terrain A exhibits a spectrum with relatively shallower 1-??m absorption and a relatively steeper red spectral slope than average Ida, while Terrain B has a deeper 1-??m absorption and a less steep red slope. The average photometric properties of Ida and Terrain A are similar while those of Terrain B differ mostly in having a slightly higher value of ????0 (0.22 versus 0.21), suggesting that Terrain B consists of slightly brighter, more transparent regolith particles. Galileo observations of Ida's satellite Dactyl over phase angles 19.5?? to 47.6?? suggest photometric characteristics similar to those of Ida, the major difference being Dactyl's slightly lower albedo (0.20 compared to 0.21). ?? 1990 Academic Press, Inc.